LOGAN WATER ALLIANCE JIMBOOMBA WWTP ... WWTP Capacity Assessment and Staging Plan Document Number:...

LOGAN WATER ALLIANCE

JIMBOOMBA WWTP CAPACITY ASSESSMENT & STAGING PLAN

TASK NUMBER: 90-12-53

MAY 2014

Jimboomba WWTP Capacity Assessment and Staging Plan

Document Number: 7600-000-P-REP-PL-8214

90-12-53 Date issued: 23/05/2014 of 94 Rev: 1

Approval Register

Date

Project Manager Submitted

Planning & Project Management Team Review

Program Review

Controlled Document – Change Register

Revision Section Changed Change Description Initial Date

A All Draft Report BM/LF 05/05/2014

B All Format draft for Program Review SS 07/05/2014

C 4.1, 6.2.1, Appendix B Reviewed and amended TP/LF 22/05/2014

1 Final Format SS 23/05/2014




TABLE OF CONTENTS

EXECUTIVE SUMMARY ................................................................................................................................. 8

1. INTRODUCTION ............................................................................................................................... 11

1.1 Objectives ...................................................................................................................................... 11

1.2 Scope ............................................................................................................................................. 11

1.3 Business Drivers ............................................................................................................................ 12

2. PLANNING CONTEXT ...................................................................................................................... 13

2.1 Background .................................................................................................................................... 13

2.2 Previous Studies ............................................................................................................................ 14

2.3 Existing Situation ........................................................................................................................... 15

3. METHODOLOGY .............................................................................................................................. 20

3.1 Key LCC Stakeholders .................................................................................................................. 21

3.2 Assumptions .................................................................................................................................. 22

3.2.1 Desired Standards of Service .................................................................................................... 22

3.2.2 General ...................................................................................................................................... 22

3.2.3 Cost Assumptions ...................................................................................................................... 22

4. WWTP EXTERNAL CONSTRAINING FACTORS............................................................................ 24

4.1 Jimboomba Wastewater Infrastructure and Flows ........................................................................ 24

4.1.1 Population and Flows ................................................................................................................ 24

4.1.2 Existing Wastewater Network .................................................................................................... 25

4.1.3 Future Wastewater Upgrades and Network Strategy ................................................................ 26

4.1.4 Catchment Growth and Pumped Flows ..................................................................................... 27

4.2 Effluent Disposal and Discharge Allowances ................................................................................ 28

4.2.1 Recycled Water Users and Requirements ................................................................................ 28

4.2.2 Future DA negotiations – Lagoon Overflow ............................................................................... 29

4.3 External Constraining Factors Summary ....................................................................................... 30

5. EXISTING WWTP CAPACITY AND PERFORMANCE .................................................................... 31

5.1 WWTP Overview ........................................................................................................................... 31

5.2 Hydraulic Assessment ................................................................................................................... 31

5.2.1 Hydraulic Infrastructure .............................................................................................................. 31

5.2.2 Observed Hydraulic Performance.............................................................................................. 33

5.2.3 Hydraulic Modelling Outcomes .................................................................................................. 34

5.3 Biological Assessment ................................................................................................................... 34

5.4 WWTP Capacity ............................................................................................................................ 35

6. PRELIMINARY OPTIONS DEVELOPMENT .................................................................................... 37

6.1 Upgrade Requirements .................................................................................................................. 37




6.2 Preliminary Options ....................................................................................................................... 37

6.2.1 Pumped Flow Management ....................................................................................................... 37

6.2.2 Inlet Works and Associated Considerations .............................................................................. 39

6.2.3 Treatment Process Options Considerations .............................................................................. 40

6.2.4 Chlorine Contact Tank Options .................................................................................................. 43

6.3 Preliminary Options Workshop Outcomes ..................................................................................... 43

6.4 Options for Further Development .................................................................................................. 44

7. DETAILED OPTION ANALYSIS ....................................................................................................... 47

7.1 Option 1 – Upgrade SBR and Peak Instantaneous Flows Balancing Tank .................................. 47

7.2 Option 2 – Upgrade SBR and Wet Weather Balancing Tank ........................................................ 50

7.3 Option 3 – Upgrade SBR and Wet Weather Bypass ..................................................................... 53

7.4 Option 4 – Duplicate SBR .............................................................................................................. 56

7.5 Option 5 – Parallel Package Plants ............................................................................................... 59

8. OPTION EVALUATION ..................................................................................................................... 62

8.1 Cost Analysis ................................................................................................................................. 62

8.1.1 Population Sensitivity Analysis .................................................................................................. 63

8.2 Multi Criteria Analysis .................................................................................................................... 64

8.3 Preferred Option and Staging ........................................................................................................ 66

8.3.1 Future considerations for the preferred option development ..................................................... 69

9. CAPITAL WORKS PROGRAM IMPLICATIONS .............................................................................. 70

10. CONCLUSION ................................................................................................................................... 71

11. RECOMMENDATIONS ..................................................................................................................... 72

12. REFERENCES .................................................................................................................................. 73

FIGURES

Figure 2-1: Jimboomba WWTP General Arrangement Plan ...................................................................... 17 Figure 2-2: Recycled Water User locations for Jimboomba WWTP .......................................................... 19 Figure 3-1: Task Methodology ................................................................................................................... 20 Figure 4-1: Jimboomba WWTP Current and Future Population Projections ............................................. 25 Figure 4-2: Jimboomba Wastewater Catchment ......................................................................................... 26 Figure 5-1: Jimboomba WWTP Aerial View ............................................................................................... 31 Figure 5-2: Jimboomba WWTP Infrastructure Schematic .......................................................................... 32 Figure 5-3: Jimboomba WWTP Future Loads and Current Capacity. ....................................................... 36 Figure 6-1: Jimboomba WWTP Pump Station Connection points with Current and Proposed flow

Monitoring ................................................................................................................................................. 40 Figure 7-1: Option 1 Infrastructure Schematic ........................................................................................... 49




Figure 7-2: Option 2 Infrastructure Schematic ........................................................................................... 52 Figure 7-3: Option 3 Infrastructure Schematic ........................................................................................... 55 Figure 7-4: Option 4 Infrastructure Schematic ........................................................................................... 58 Figure 7-5: Option 5 Infrastructure Schematic ........................................................................................... 61 Figure 8-1: Preferred Option Site Master Plan ........................................................................................... 68 Figure -B1: Jimboomba Wastewater Catchment ........................................................................................ 79 Figure -B2: Jimboomba Wastewater Configuration (Up to 2021) - Schematic ......................................... 79 Figure B-12-3: Stage A SPS73 – Duty / Assist Single Pump Operation (RM DN80, n = 100%) ............. 85 Figure B-12-4: Stage A SPS74 – Duty / Standby Single Pump Operation (RM DN150, n = 88%) ......... 85 Figure B-12-5: Stage B SPS73 – 2021 Duty / Standby Single Pump Operation (RM DN150, n = 90%) 87 Figure B-12-6: Stage B SPS74 – 2021 Duty / Standby Single Pump Operation (RM DN150, n = 95%) 87

TABLES

Table 0-1: Cost and Non-Cost Comparison Between Upgrade Options .................................................... 9 Table 2-1: Overview of Recycled Water Users and controls for Jimboomba WWTP Effluent ................. 18 Table 3-1: Consultation with Key LCC Stakeholders ................................................................................ 21 Table 4-1: Population projections and wastewater loads for the Jimboomba WWTP .............................. 24 Table 4-2: Pump Station Capacity – Existing and 2016 PWWF ............................................................... 27 Table 4-3: Jimboomba WWTP RWMP Critical and Quality Control Points and their respective critical

limits and alert levels ....................................................................................................................................... 28 Table 4-4: Jimboomba WWTP TN and TP performance 2010-2013, including adopted upgrade limits .. 29 Table 5-1: WWTP key infrastructure and their capacities ......................................................................... 33 Table 5-2: Indicative outcomes of simplstic hydraulic modelling .............................................................. 34 Table 6-1: Upgrade Requirements for Jimboomba WWTP ...................................................................... 37 Table 6-2: Upstream pump controls and resulting maximum WWTP inflow rates ................................... 38 Table 6-3: Preliminary Options Workshop Options Overview ................................................................... 44 Table 6-4: Overview of Developed Upgrade Options for Further Analysis ............................................... 46 Table 7-1: Option 1 - Description of Works ............................................................................................... 47 Table 7-2: Option 1 – Capital Cost Estimate, Staging and Schedule ....................................................... 48 Table 7-3: Option 1 – Benefits and Disadvantages .................................................................................. 48 Table 7-4: Option 2 - Description of Works ............................................................................................... 50 Table 7-5: Option 2 – Capital Cost Estimate, Staging and Schedule ....................................................... 51 Table 7-6: Option 2 – Benefits and Disadvantages .................................................................................. 51 Table 7-7: Option 3 - Description of Works ............................................................................................... 53 Table 7-8: Option 3 – Capital Cost Estimate, Staging and Schedule ....................................................... 54 Table 7-9: Option 3 – Benefits and Disadvantages .................................................................................. 54




Table 7-10: Option 4 - Description of works ................................................................................................ 56 Table 7-11: Option 4 – Capital Cost Estimate, Staging and Schedule ....................................................... 56 Table 7-12: Option 4 – Benefits and Disadvantages .................................................................................. 57 Table 7-13: Option 5 - Description of Works ............................................................................................... 59 Table 7-14: Option 5 – Capital Cost Estimate, Staging and Schedule ....................................................... 59 Table 7-15: Option 5 – Benefits and Disadvantages .................................................................................. 60 Table 8-1: Capital, Operational and NPV Cost Comparison Across Jimboomba WWTP Upgrade Options

................................................................................................................................................. 62 Table 8-2: Population Sensitivity Assessment – NPV Comparison .......................................................... 63 Table 8-3: MCA Framework and Weighting ............................................................................................. 64 Table 8-4: MCA Outcomes........................................................................................................................ 65 Table 8-5: Preferred Option Costs and NPV Compared with Option 4 .................................................... 66 Table 8-6: Preferred Option Itemised Works and Staging ........................................................................ 67 Table 9-1: Capital Works Program Amendments ..................................................................................... 70 Table B-1: Jimboomba Network Loadings – 2014 to 2021 Planning Horizons ......................................... 80 Table B-2: Pump Station Capacity – Existing and 2016 PWWF ............................................................... 83 Table B-3: Stage A Network Operation – Prior to Jimboomba WWTP Capacity Augmentation ............... 84 Table B-4: Stage B Network Operation – Post Jimboomba WWTP Capacity Augmentation ................... 86

APPENDICES

Appendix A Desired Standards of Service Appendix B Jimboomba Wastewater Catchment Pump Station Management Analysis Appendix C Jimboomba WWTP Performance Assessment and Existing SBR Upgrade Reports (Hartley,

2014) Appendix D Preliminary Options Matrix Appendix E Capital Cost and NPV




ABBREVIATIONS

ADWF Average Dry Weather Flow

BOD Biological Oxygen Demand

CED Common Effluent Drainage

CCT Chlorine Contact Tank

CWP Capital Works Program

DA Development Approval

DEHP Department of Environment and Heritage Protection

DSS Desired Standards of Service

EP Equivalent Population

FY Financial Year

HRT Hydraulic Retention Time

IDM Infrastructure Demand Model

LCC Logan City Council

LWA Logan Water Alliance

MCA Multi-Criteria Assessment

MLSS Mixed Liquor Suspended Solids

NPV Net Present Value

PDF Peak Dry Flow

PPS Private Pump Station

PWWF Peak Wet Weather Flow

RWMP Recycled Water Management Plan

SBR Sequencing Batch Reactor

SPS Sewerage Pump Station

TN Total Nitrogen

TP Total Phosphorus

TWL Top Water Level

VSD Variable Speed Drive

WWTP Wastewater Treatment Plant




EXECUTIVE SUMMARY

The Jimboomba Wastewater Treatment Plant (WWTP) currently services the township of Jimboomba.

Recent upgrades in the wastewater network have increased peak instantaneous flows to the WWTP,

disturbing the biological process of the plant and affecting the overall effluent quality. On occasions, the

process has been effectively ‘washed away’, resulting in poor effluent quality until the biological process can

recover. Since September 2013, blue-green algal blooms have consistently been sighted in the effluent

storage lagoon, attributed to poorer effluent quality. Blue-green algae sightings have restricted recycled

water use, which is the main form of effluent disposal.

Strategic Planning includes the construction of the proposed Cedar Grove WWTP by 2021; with network

growth to be accommodated at the Jimboomba WWTP up to this time; however, the Jimboomba WWTP is

currently operating at (or near) capacity. As the WWTP is intended as an ‘interim’ asset until construction of

Cedar Grove WWTP, any interim upgrades need to be considered to balance between adequate treatment

and capital expenditure.

This current planning study includes an assessment of the current capacity and performance of the

Jimboomba WWTP and identifies cost effective works to improve plant performance and increase plant

capacity in the short-term to facilitate forecast population growth up to 2021.

Jimboomba WWTP Capacity Assessment

The Jimboomba WWTP consists of an inlet works with coarse screening, a continuously fed, intermittently

decanted sequencing batch reactor (SBR), a chlorine contact tank (CCT), and an 18 ML recycled water

storage lagoon. The site also has two sludge lagoons and an onsite sludge dewatering facility. The treatment

plant is producing Class C effluent after the effluent storage lagoon, which is distributed to recycled water

users via their private infrastructure.

Based on biological and hydraulic assessments, the Jimboomba WWTP has a biological capacity of 1,500

EP and is limited to a flow of approximately 30 L/s in the SBR. Observed constraints at the plant include

MLSS (sludge) overflow from the SBR at plant inflows greater than around 30 L/s, whereas, the biological

capacity is limited to the tank volume and aeration capacity.

The inlet works are also constrained to approximately 35 L/s and the Chlorine Contact Tanks to 31 L/s (at a

9 minute hydraulic retention time).

Population, Flows and External Constraints

The population growth in Jimboomba is uncertain. An assessment of the previous planning estimates in the

Jimboomba WWTP Upgrade Project Development (LWA, 2011) and recent development applications and

changes result in a population estimated for 2021 of 2,730 EP. These estimates are yet to be verified against

the new Infrastructure Demand Model (still in progress). Due to the high proportion of CED systems in the

current network, the revised 2021 biological load is approximately 2,530 EP.




The LCC pump stations that discharge direct to the WWTP have no VSD or systemic controls and can be as

high as 49 L/s with the current infrastructure configuration, increasing to a maximum of 78 L/s through

planned upgrades and reconfigurations. This inflow is far above the treatment limit of the SBR at 30 L/s. A

range of pump station management strategies were investigated and the preferred and most practical option

is the management of pump stations to reduce peak instantaneous flows to the WWTP to 54 L/s:

· SPS73 and SPS74 include VSD flow limitations to restrict peak pumped flow to the minimum

required for adequate pipe velocity, while meeting PWWF

· Systemic controls between pump stations to ensure that the two LCC pump stations do not pump at

the same time, except in extreme wet weather events

Negotiations with DERM are underway for operational license modifications to allow lagoon effluent release

to Hendersons Creek during wet weather. Additional water quality and receiving environment restrictions are

anticipated, and are assumed as the same or better than current performance for this study.

Options Assessment

Five detailed upgrade options were developed, based on a future maximum pumped flow of 54 L/s and

contributing population of 2,600 EP by 2021:

· Option 1 – Upgrade SBR and Peak Instantaneous Flows Balancing Tank

· Option 2 – Upgrade SBR and Wet Weather Balancing Tank

· Option 3 – Upgrade SBR and Wet Weather Bypass to CCT

· Option 4 – Duplicate SBR

· Option 5 – Parallel Package Plant.

Options 1 to 3 involve increasing the SBR tank capacity, weir length and aeration capacity. The duplicate

SBR and parallel package plant options were anticipated to cater for both biological and hydraulic

requirements. All options include an upgrade to the inlet works and CCTs and also assume that pumped flow

management is adopted in the catchment, reducing peak instantaneous flows to 54 L/s.

Table 0-1 shows the cost and non-cost assessment between WWTP upgrade options.

Table 0-1: Cost and Non-Cost Comparison Between Upgrade Options

Option 1 –

Upgrade SBR and peak flow balancing tank

Option 2 – Upgrade SBR &

wet weather balancing tank

Option 3 – Upgrade SBR

and wet weather bypass

Option 4 – Duplicate SBR

Option 5 – Parallel

Package Plant

Capital cost (2014 $) $2.4m $2.6m $2.5m $2.6m $3.6m

NPV (over 25 year period) $12.7m $12.8m $12.6m $12.3m $13.9m




% Variation from lowest NPV 3.1% 4.2% 2.3% 0.0% 14.8%

Cost Rank 3 4 2 1 5

MCA Score (out of 10) 2.52 5.32 2.42 8.62 8.66

Non-Cost Rank 4 3 5 2 1

Based on the cost and non-cost considerations, duplicating the SBR to accommodate hydraulic and

biological increases (Option 4) is the preferred option, with a low capital and NPV cost, a high MCA scoring

and the flexibility to stage works with flow balancing during the initial stages.

The preferred option is a modified version of Option 4, which included the small balance tank, for balancing

instantaneous average day pumped flows, followed by duplication of the SBR to accommodate hydraulic and

biological increases. Due to the anticipated scheduling for design completion and construction funding, the

SBR upgrade is proposed to be completed in one stage. The duplicate SBR option also allows for some

flexibility in the construction of the transfer pipeline to the proposed Cedar Grove WWTP. The preferred

staging and capital works to be added to the capital works budget equates to a total of $2.8m for the upgrade

of Jimboomba WWTP:

· FY14/15 – inlet works upgrade and installation of an instantaneous peak flow balance tank ($0.37m)

· FY15/16 – new SBR unit and upgrade CCTs ($2.4m)

Recommendations

The Logan Water Alliance recommends that Logan City Council (LCC):

1. Adopt the construction of a duplicate SBR as the preferred upgrade strategy for the Jimboomba

WWTP, which incorporates the following works:

a. Stage 1 (FY14/15) – install new inlet works and fine screen with 30 kL flow balancing tank

b. Stage 2 (FY15/16) – commission a duplicate SBR and chlorine contact tanks

2. Proceed with the detailed design of the inlet works and 30 kL balance tank

3. Implement pump station management of the upstream LCC operated pump stations, which involves:

a. Stage A (pre-WWTP commissioning) – delaying SPS73 connection to 150 mm rising main,

VSD control and duty/standby operation of SPS74, and installing systemic control between

SPS73 and SPS74

b. Stage B (post WWTP upgrade) – VSD control, duty/standby operation and limiting flows to

minimum velocity requirements for SPS73 and SPS74




1. INTRODUCTION

The Jimboomba Wastewater Treatment Plant (WWTP) currently services the township of Jimboomba, which

forms part of the Logan South wastewater network.

Recent upgrades within the local wastewater network have increased the peak instantaneous flows that can

be transferred to the WWTP. The increased peak flows have disturbed the biological process of the

treatment plant and affected overall effluent quality. On occasions, the process has been effectively ‘washed

away’, resulting in poor effluent quality until the biological process can recover.

Since September 2013, blue-green algal blooms have consistently been sighted in the WWTP effluent

storage lagoon. These algae blooms have been attributed to the poorer effluent quality from increased flows

to the WWTP and also the detrimental effects from contamination by Hendersons Creek during a peak storm

event in January 2013. Blue-green algae sightings have restricted recycled water use, which is the main

form of effluent disposal.

The proposed Cedar Grove WWTP is scheduled for construction in 2021 and will replace the Jimboomba

WWTP; however, the Jimboomba WWTP is suspected to operating at or near capacity. A capacity

assessment is required to determine timing for interim upgrades before the transfer to Cedar Grove WWTP

can be constructed. As the Jimboomba WWTP is intended only to be an ‘interim’ asset, a balance between

adequate treatment upgrade and capital expenditure is imperative.

This planning report outlines the capacity assessment of the current Jimboomba WWTP and details upgrade

strategies to maintain adequate operation of the WWTP until the network flows are diverted to the proposed

Cedar Grove WWTP.

Objectives The objective of this planning study is to confirm the current capacity and performance of the Jimboomba

WWTP and to identify works required to improve plant performance and meet capacity projections prior to

the transfer of flows to the proposed Cedar Grove WWTP.

Scope

The scope for this planning study includes a number of processes:

· Review related planning documentation and monitoring data

· Review population forecasts in consultation with LCC Water Development Services

· Undertake site visit to identify constraints/opportunities with LCC Treatment Operators

· Identify process bottlenecks in terms of equivalent populations (EPs)

· Investigate short term solutions to relieve peak inflows to WWTP

· Identify minor works that can be undertaken to improve plant capacity

· Undertake a first principles cost estimation for all options

· Undertake population sensitivity analysis for identified options




· Undertake stakeholder workshop with LCC Planning, LCC Asset Management and LCC Treatment

· Select the preferred option in conjunction with key stakeholders

· Develop a master plan for WWTP site

· Prepare draft and final reports

The scope of this current study does not include the management and control of effluent.

Business Drivers The business drivers for undertaking works at the Jimboomba WWTP are identified as follows:

Growth A review of previous planning, the 2010 Infrastructure Demand Model (IDM) and current development

applications has indicated that the contributing catchment population to the Jimboomba WWTP is projected

to increase from approximately 1,680 EP (Equivalent Population) in 2014 to approximately 8,150 EP at

ultimate development (nominally 2051). This increase represents an average annual growth rate of

approximately 4.4%.

The catchment contains areas of common effluent drainage (CED) systems, which effectively reduces the

biological load (in EPs) to approximately 1,480 EP for the 2014 (current) system.

Previous planning has indicated that the WWTP has a capacity of approximately1,500 EP, and is anticipated

to reach this limit by 2015.

Compliance Compliance with the WWTP development approval (DA) (or operating licence) is part of the legal

requirement for operating the plant. LCC also has a general environmental duty to prevent or mitigate the

risk of environmental harm, as outlined in the Environment Protection Act 1994. The current DA does not

stipulate water quality limits for disposal, however, does indicate that recycled water guidelines needs to be

adhered to for safe practice of recycled water use. No releases to waterways are allowed under the current

DA.

The DA is currently under review for release of treated waters to the nearby Hendersons Creek during wet

weather. Any released flows will need to have no negative impact on the receiving waters.

Ineffective treatment due to biological overload, or alternatively hydraulic overload impacts such as sludge

and solids carryover from the treatment into the effluent, will likely decrease the stored effluent water quality.

This could negatively impact third party users of recycled water or future releases to Hendersons Creek.

Improvement Recent improvements to the SPS74 (JMSP2) pump flowrate in August 2013 and a lack of private pump

stations control, has resulted in high peak pumped flows to the plant during both wet and dry weather. These

high flow rates have impacted the inlet screen pit and caused biological process loss or ‘washout’ on several

occasions.

Managing these flow variations is essential to ensuring the existing and future WWTP processes are not

impacted.




2. PLANNING CONTEXT

Background

The Jimboomba WWTP services the Jimboomba village population of around 1,600 EP. During the 2008

Water Reform, Jimboomba WWTP was transferred to Logan City Council’s (LCC’s) jurisdiction from

Beaudesert Shire Council. It is now located in LCC’s Southern District.

Approximately 60% of the existing Jimboomba catchment is serviced via a common effluent drainage (CED)

system. The CED system involves primary settlement of wastewater in on-site septic tanks, before the

effluent is discharged to the treatment plant via reduced diameter mains, lowering the biological and

hydraulic load on the treatment plant by around 25%.

All wastewater from the catchment is currently pumped to the WWTP via four pump stations: SPS73, SPS74

and two private pump stations. Recent rising main upgrades at SPS74 in 2013 have increased the pumped

flowrate to the plant. Upgrades at SPS73 have recently been completed (but not commissioned) and will also

increase pumped flow to the WWTP.

All treated effluent flows historically have been used for land irrigation, primarily to the Hills College and Golf

Course. An additional recycled water user in a local horse paddock has also been approved. A minor amount

of effluent is also used to irrigate vegetation within the treatment plant boundaries. All effluent is stored in an

onsite effluent storage lagoon, prior to transfer. DA requirements only stipulate a level of quality that meets

local recycled water guidelines, with no unique quality limits for the Jimboomba WWTP. There is currently no

allowance in the DA for overflow from the lagoon into the adjacent Hendersons Creek, however, negotiations

for an overflow discharge with DEHP are being progressed.

A WWTP process refinement and tuning study was conducted in 2008/09 in conjunction with an upgrade and

irrigation strategy to accommodate estimated flow projections. Following this study, designs for a conversion

to an MBR was rejected in 2010 due to significant costs and acknowledgement that a high level of water

quality was not required for golf course irrigation purposes. The Jimboomba WWTP Upgrade – Project

Development planning study (LWA, 2012) included revised population projections, indicating that growth was

not as high as originally estimated and concluded that only minor operational improvements were required

until population growth reached plant capacity.

Strategic planning impacts within the area include a deferral of the transfer of the Jimboomba wastewater

catchment to Cedar Grove until 2021. Approximately $10m of infrastructure is required to complete the

transfer, prior to the decommissioning of Jimboomba WWTP.




Previous Studies Previous planning studies that provide background to this current planning study are outlined below:

n 90-10-87-001 - Jimboomba WWTP Upgrade Project Development (LWA, November 2011) – This

report identified that the plant currently has the capacity to treat a biological loading of 1,500 EP. The

Development Approval did not allow for discharge to water bodies. All effluent was stored at the effluent

storage lagoon located at the treatment plant or pumped to the Hills Education Foundation Irrigation

Lagoon. The effluent is currently treated to a Class C recycled water standard.

The outcomes of this study determined that:

- management of peak wet weather flows to the plant is required to protect the biological process

- only minor works and operational adjustments were required in the short term

- a conveyance solution from Jimboomba to the new Cedar Grove WWTP is the preferred servicing

strategy and would be required between 2015 and 2021

n LWA Work Package 7603 - Jimboomba WWTP Upgrade - In 2009 and 2010, the design of a upgrade

at Jimboomba WWTP was undertaken as part of Work Package 7603. The design proposed to upgrade

the plant to a Membrane Biological Reactor (MBR) process with a capacity of 2,600 EP. This design was

approximately 50% complete when it was identified that the Cedar Grove WWTP was likely to be the

preferred WWTP location for the Logan South wastewater network. The design was subsequently put on

hold until the Jimboomba WWTP Upgrade Project Development Report (November 2011) verified the

preferred servicing strategy for Jimboomba.

n LWA Work Package 7617 - Jimboomba Sewerage Rising Main Upgrade - The existing DN80 rising

mains from pump stations SPS73 and SPS74 were upgraded to DN150 in 2012 and the SPS74 rising

main was brought online by September 2013. Variable speed drives (VSDs) were proposed to be fitted to

these pump stations to provide flow control, though are yet to be completed. Due to uncertainty

surrounding the effects of increased flows to the plant on the biological process, it was recommended

that only SPS74 be switched over to the new DN150 main.

n 90-11-46 - Jimboomba WWTP Recycled Water Management Plan (LWA, 2013) – A legal document

outlines the recycled water users, key recycled water infrastructure, recycled water guidelines and any

adopted risk mitigation for the effluent disposal of Jimboomba WWTP. This document contains reference

to recycled water agreements between users and highlights guideline practices and key control

measures adopted by LCC.

n 90-12-42 - Jimboomba WWTP - Wet Weather Overflow Mitigation Strategy (LWA, ongoing) – The

review of wet weather overflows from the WWTP effluent (and irrigation storage) lagoon was driven by a

Show Cause notice from DEHP for uncontrolled overflow during dry weather, resulting from flooding of

the lagoon from Hendersons Creek and previous weeks of continuous rainfall. This study identified

controlled release measures to manage the lagoon levels during low irrigation periods. The DA with




DEHP is currently under revision to allow controlled release to Hendersons Creek during wet weather. A

number of options for wet weather storage were considered and discarded as part of this study.

n 90-12-33 - East Street Jimboomba Wastewater Conveyance - Detailed Planning and Preliminary Design (LWA, December 2013) – Planning for the conveyance of waste water flows from the

undeveloped south east of the catchment was revised in light of developer applications and delay of

Cedar Grove WWTP. The revised Jimboomba wastewater network operation was incorporated into

pumped flow estimates for this report.

n 90-12-21 - Revision of Logan South Wastewater Network Servicing Strategy (LWA, January 2014)

– This report re-examined the preferred servicing strategy for the Logan South wastewater network

based on new population forecasts provided by Economic Development Queensland for the Yarrabilba

and the Greater Flagstone Priority Development Areas. This study identified Jimboomba and Flagstone

WWTP capacities of 1,500 EP and 2,550 EP respectively. It concluded that conveyance to the new

Cedar Grove WWTP remains the preferred option for the Jimboomba Township; however, the

construction of the Cedar Grove WWTP could be deferred until 2021.

Existing Situation

Jimboomba Wastewater Catchment

As part of Work Package 7617 – Jimboomba Sewerage Upgrade, the existing DN80 rising mains from pump

stations SPS73 and SPS74 were upgraded to DN150. This rising main upgrade effectively increased the

pumping capacity at these two pump stations from approximately 6 L/s to 21 L/s (with one pump running at

each pump station).

Variable speed drives (VSDs) have been installed but not yet commissioned at these pump stations to

provide flow control and to reduce peak pumping to peak wet weather flow rates. At the time of SPS73 and

SPS74 rising main installation, only SPS74 was at capacity during wet weather events and therefore it was

connected to the new DN150 main. SPS73 is anticipated to be connected to its new rising main when

SCADA data indicates that it is unable to accommodate peak wet weather flows through the smaller

diameter rising main.

Overflow structures have been installed at both pump stations, with basic screening on SPS73 and a baffle

plate on SPS74 (pers. comms, L Bridgham, LCC, 14th April 2014).

Wastewater Treatment Plant (WWTP)

The Jimboomba WWTP consists of:

· a 20 mm bar-screen inlet works

· a single continuously fed sequence batch reactor (SBR) with intermittent decant

· a 17 kL chlorine contact tank (CCT)

· an 18 ML effluent storage lagoon




· two sludge lagoons

· a mobile fan press for sludge dewatering

The inlet screen is planned to be upgraded in 2014.

The WWTP is currently operates with 5 cycles per day and produces a standard quality effluent for a

continuously-fed SBR on dry weather days. Increased peak flows regularly disturb the biological process of

the plant affecting the overall effluent quality, particularly when the plant is in ‘settle’ mode, resulting in

settled sludge uplifting over the weir into the chlorine contact tanks.

Recent storm events (March 2013) have highlighted the impact of the upgraded peak instantaneous flows to

the WWTP. Consistent wet weather pumped flows to the WWTP above 30 L/s impacted the biological

process, causing the mixed liquor suspended solids (MLSS) to be ‘washed away’. The loss of MLSS due to

high flows has occurred on a number of occasions, and typically results in poor effluent quality until the

biological process recovers (approximately 2 weeks). In the March 2013 event, raw wastewater also backed

up from the inlet works through associated pipework and into the sludge storage lagoon, which was able to

contain the raw wastewater as it was almost empty at the time of the storm event. Shorter periods of high

flowrate pumping have occasionally resulted in near spills from the Inlet Screen Pit (November 2013).

Figure 2-1 shows the general arrangement plan of Jimboomba WWTP.




Figure 2-1: Jimboomba WWTP General Arrangement Plan




Recycled Water Storage and Users

All recycled water is disposed through local irrigation and generally meets recycled water guidelines and

requirements. Table 2-1 and Figure 2-2 outlines the current recycled water users for Jimboomba WWTP.

Table 2-1: Overview of Recycled Water Users and controls for Jimboomba WWTP Effluent

User 1 User 2 User 3

Proprietary Name Logan City Council Hills Educational Foundation Ltd Brisbane Property Pty Ltd

Land Parcel RP859595/28 RP859595/1 RP151380/2 SP203522/3

Recycled Water Permitted Use

WWTP open space irrigation

Golf course and school garden irrigation Horse paddock irrigation

Type of Irrigation Traveller irrigation Spray Irrigation Traveller irrigation Recycled Water Quality Requirement

Class C Recycled Water 95% of samples <1000 cfu/100 mL

Support Documentation Recycled Water management Plan: Exemption Guidelines – Appendix 1

Key on-site control measures

· Signage and colour coding

· Training and inductions

· Low throw sprinklers

· Vegetation barriers · Cease irrigation

during windy days

· Signage and colour coding · Staff training and awareness · Restricted access · Buffer zone (40 m) · Withholding period (no

access during or for 4 hours after irrigation)

· Midnight irrigation · No high pressure sprinklers

for school gardens · Algae control

· Signage and colour coding · Visitor training and

awareness · Fencing · Buffer zone (>50 m) · Cease irrigation during windy

days · Protect horse water trough · Restrict horses until grass

paddock is dry · Restrict use if any algal

blooms sighted Recycled Water Agreement in place NA Yes Yes




Figure 2-2: Recycled Water User locations for Jimboomba WWTP

The Golf Course (User 2) is supplied via a privately-owned pump station, which conveys effluent to the Hills

Golf Course lagoon on-site. The horse paddock (User 3) and WWTP site (User 1) is supplied via a separate

council-owned pump station located on the other side of the lagoon.

Recent consistent blue-green algae outbreaks have limited the use of recycled water for irrigation to local

horse paddocks due to the risk to livestock and public. The consistent outbreaks have been attributed to

poorer treatment quality which has likely occurred due to the recent catchment upgrades. LCC has installed

an algae management unit, consisting of a carbon filter, in the attempt to mitigate blue-green algae

outbreaks.

No overflow discharge is allowed in the current DA; however, negotiations with DEHP are planned to

incorporate this into the licence. Ideally, the changes will include discharge to the adjacent Hendersons

Creek during wet weather events when the creek is flowing. The discharge limits in a revised DA are

uncertain for overflow during wet weather, although it is expected that there may be quality limits and creek

dilution factors.




3. METHODOLOGY Figure 3-1 describes the methodology for this Task.

Stage 1 Background

•Review background information •Confirm project drivers including business case reviiew •Review existing population forecasts •Review historical WWTP monitoring data

Stage 2 Minor Works Options

Assessment

• Identify process bottlenecks • Investigate short term solutions to relieve peak flows • Identify minor works to improve plant capacity •Hold stakeholder workshop to confirm minor works augmentation strategy •Undertake population sesnitivity analysis for minor works augmentation strategy

Stage 3 Major Works Options

Assessment

•Develop detailed options for longer term augmentation strategy (next 10 – 15 years)

•Undertake first principles cost estimation for all options •Hold a stakeholder MCA workshop to discuss the costs, benefits and challenges of each option

•Agree preferred option and develop master plan for WWTP site

Figure 3-1: Task Methodology




Key LCC Stakeholders Table 3-1 summarises the key stakeholders that were consulted at various stages during this study. An

options workshop was held at Jimboomba WWTP with LCC stakeholders to identify potential options, and a

final MCA workshop was held at LWA office with LCC stakeholders. Regular meetings and site visits were

held with LCC plant operations to discuss project progress and to investigate option feasibility, and to

present findings of the investigation.

Table 3-1: Consultation with Key LCC Stakeholders

Function Name Position Level of Consultation

Water Business Daryl Ross Logan Water Business Manager · MCA workshop

Water Development Services Marco Bonotto

Water Development Services Program

Leader · MCA workshop

Treatment Imtiaj Ali Treatment Engineer

· Preliminary options workshop · Site Meetings · Receiving Environment Meeting · Ongoing consultation throughout the

duration of the Task · MCA workshop

Treatment Bill Smith Plant Operator

· Preliminary options workshop · Site Meetings · Ongoing consultation throughout the

duration of the Task · MCA workshop

M&E Operations Darshan Udayaratna

Mechanical & Electrical Operations Program

Leader · Pump Station Management Meeting

M&E Operations Lester Bridgham Mechanical & Electrical Supervisor · Pump Station Management Meeting

Water Product Quality Chris Pipe-Martin Product Quality

Program Leader -

· Preliminary options workshop · Receiving Environment Meeting · MCA workshop

Water Product Quality Amy Flynn

Environmental Management Systems

Officer

· Site Meetings · Preliminary options workshop · Receiving Environment Meeting · MCA workshop

Water Product Quality Kambez Akrami

Product Quality Systems Officer

· Receiving Environment Meeting · MCA workshop

Asset Management Darren Moore Water Asset

Management Program Leader

· MCA workshop




Asset Management Troy Kasper Water Cycle Planning Coordinator · MCA workshop

Water Cycle Planning Jackie Clutten Water Cycle Planning Coordinator · MCA workshop

Assumptions

3.1.1 Desired Standards of Service Logan City Council’s Desired Standards of Service (DSS) for Wastewater systems and treatment plants and

included within Appendix A.

3.1.2 General In addition to the DSS, the following general assumptions are adopted for this planning study:

Population and inflow:

· CED systems reduce biological and hydraulic loading by 25%

· No future CED systems to be incorporated to WWTP catchment

· 2010 IDM populations are adopted as a basis for further adjustment based on LCC development

information, taken from the report Jimboomba WWTP Upgrade Project Development (LWA,

November 2011) and adjusted.

Hydraulic assumptions:

· Inlet screen headloss equates to upstream overflow at the sludge lagoon at 37 L/s

· Site contributions to inlet pit flows are less than 1 L/s, thus not significant

Treatment assumptions:

· The existing SBR weir only lowers 0.45 m, not the full 0.6 m (as observed by LCC Operators)

· Alum dosing will be required for blue green algae management in future

· Alum and pH dosing assumed to be part of a package plant (so not itemised separately)

· All upgrades should produce effluent of similar standard or better to meet potential DEHP lagoon effluent release requirements (negotiations currently on hold).

3.1.3 Cost Assumptions Cost estimates were developed for all identified options and are based on the following assumptions:

Capital costs:

· Quotations from suppliers

· First principles estimates for civil works provided by LWA estimator (where appropriate)

· 30% contingency allowance




· All capital costs are shown in 2014 dollars and are provided in the appendices

Operational costs:

· cost of electricity = $0.15/kWh

· Maintenance costs = 1% of capital costs

· Yearly allowance of extra chemical use of $5,000 p.a.

· Labour allowance, at $50/hr, up to 3 days/week, dependant on upgrade operational complexity

· The Operational Cost Estimates are shown in 2014 dollars and are provided in the appendices

NPV Analysis:

· Net present value (NPV) assessments will be undertaken over a period of 25 years

· The discount rate applied is LWA standard 4.75%




4. WWTP EXTERNAL CONSTRAINING FACTORS This section details the upstream and downstream constraining factors that affect Jimboomba WWTP

process, including a review of the catchment contributing population (refer to Appendix B for more detail).

Jimboomba Wastewater Infrastructure and Flows

4.1.1 Population and Flows The Jimboomba WWTP operational records indicate that the WWTP currently receives approximately

241 kL/d average daily flow, increasing from 222 kL/d in 2012/13. The plant has also received peak daily

flows of 1027 kL/d within a 24 hour period (March 2014).

The updated IDM projections were not available for this current study; therefore, population projections for

the Jimboomba WWTP were adopted from the Jimboomba WWTP Upgrade Project Development (LWA,

November 2011). These estimates were adjusted to incorporate recent development applications and

planning changes, as detailed in Table 4-1 and Figure 4-1. The impact of the CED system (approximately

60% of the existing catchment) is a reduction of 25% biological load and 50% PWWF, also shown in Table

4-1 and Figure 4-1 below.

Table 4-1: Population projections and wastewater loads for the Jimboomba WWTP

2014 2016 2021 2026

Total EP 1,678 2,144 2,735 3,840

Total ADWF Load (kL/d) 335 430 548 767

Biological EP 1,480 1,940 2,530 3,630




Figure 4-1: Jimboomba WWTP Current and Future Population Projections

These population and flow estimates are slightly less conservative than the Logan South Wastewater

Servicing Plan (LWA, January 2014) which did not provide detail on division of EP across the catchment

pump stations flowing directly to the WWTP. Wastewater loads have been calculated based on the Logan

Water Desired Standards of Service (DSS) which incorporate the reduced loads and flow of the CED

systems.

4.1.2 Existing Wastewater Network The existing wastewater network consists of traditional gravity sewers, common effluent drainage (CED)

systems, five Council owned sewerage pump stations (SPS), two existing and one future private pump

stations (PPS). Figure 4-2 provides an overview of the Jimboomba wastewater catchment and its

infrastructure.

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TOTAL EP:

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PWWF (L/s)




Figure 4-2: Jimboomba Wastewater Catchment

The WWTP receives flows directly from SPS73, SPS74, Hills College PPS and the Johanna St Child Care

Centre PPS. An additional private pump station is planned for the catchment, which will be associated with a

future Stockland development (i.e. Stockland PPS).

The rising main arrangement associated with SPS73 and SPS74 is as follows:

· Pump station SPS73 transfers flows to the WWTP via a DN80 rising main. A new DN150 rising

main augmentation has been constructed, but is yet to be commissioned.

· Pump station SPS74 has recently been connected to an augmented DN150 rising main to increase

the capacity of the pump station due to its history of wet weather overflows.

4.1.3 Future Wastewater Upgrades and Network Strategy The East Street Jimboomba Wastewater Conveyance – Detailed Planning and Preliminary Design (LWA,

Jan 2014) Planning Report outlines the current adopted servicing strategy for Jimboomba. The high level

servicing strategy for the Jimboomba catchment is based on the transfer of flows to the planned regional

Cedar Grove WWTP in 2021. At this time the transfer infrastructure, consisting of a new pump station and

7.5 km of DN375 rising main, will be constructed to convey flows from Jimboomba to Cedar Grove allowing

the decommissioning of the Jimboomba WWTP. During the expected life of Jimboomba WWTP (i.e. up to

2021) the following catchment changes are anticipated:

1. Growth in the south east (i.e. near East Street) will require a new SPS76 to transfer flows to SPS74

until 2021, and a new SPS80 pumping flows to SPS73




2. SPS73 will be connected to its new DN150 rising main to increase capacity

3. Stockland development along the west of the Mount Lindsay Highway is likely to be completed in the

next few years. It is proposed to connect the Stockland private pump station to the disused SPS74

DN80 rising main

4.1.4 Catchment Growth and Pumped Flows Five pump stations will contribute flows directly to the Jimboomba WWTP between now and 2021. These

include:

· Two Council owned pump stations (i.e. SPS73 and SPS74)

· Three privately owned pump stations, which include two existing pump station assets (i.e. Hills

College and the Johanna St child care facility) and the future pump station to service the Stockland

development.

Table 4-2 shows the current pump station capacities compared to PWWF up to 2021.

Table 4-2: Pump Station Capacity – Existing and 2016 PWWF

Pump Station RM Nominal Diameter

Single Pump (Duty) Flow

Dual Pump (Duty / Assist)

Flow

2014 PWWF

2016 PWWF

2021 PWWF

[-] [mm] [L/s] [L/s] [L/s] [L/s] [L/s]

SPS73 80 6.7 1 7.0 1 7.6 8.4 10.9

SPS74 150 25.7 1 29.7 1 9.9 13.8 19.6

Hills College 100 8.3 3 - 3 2.0 2.0 2.0

Johanna St Child Care 50 2 2.4 4 4.0 5 0.2 0.3 0.3

Stockland 80 4.5 6 6 6 NA 1.8 2.1

Total 47.6 55 19.7 26.3 34.9 Notes: 1 – Capacity was based on pump station drawdown test with SPS73 connected to a DN80 rising main and SPS74 connected to the existing DN150 rising main 2 – A DN50 rising main has been assumed. This will need to be confirmed in the field. 3 – Flow rate based on ‘as constructed’ drawings and system resistance curves provided. No information provided as to pump configurations and a single pump configuration is assumed. 4 – Minimum flow based on a minimum 0.9 m/s velocity requirement and DN50 rising mains. The DN50 pipe would have a 45 mm internal diameter for an assumed PE pipeline. 5 - Maximum flow based on a maximum 2.5 m/s velocity requirement and assuming DN50 rising mains. The DN50 pipe would have a 45 mm internal diameter for an assumed PE pipeline. 6 - Minimum flow based on a minimum 0.9 m/s velocity requirement and DN80 rising mains. A maximum flow rate based on a maximum 2.5 m/s velocity requirement in a DN80 rising main is likely to concur high head loss and unlikely to meet this requirement. Therefore, the flow is unlikely to exceed 6 L/s.

The following can be deduced:

· The current capacity of SPS73 (i.e. PWWF 7.0 L/s) is below the expected DSS requirement in 2016

(i.e. PWWF 8.4 L/s). However, a review of actual SCADA suggests that flows into the pump station

are currently less than current projected flows.

· The current capacity of pump station SPS74 is well in excess of DSS requirements in 2016




· Drawdown test results used for this study show a close correlation with theoretical calculations for

SPS73, but a significant error is applicable in relation to SPS74 (refer Appendix B). Further

investigation is required to confirm asset characteristics for SPS74.

· The total peak flows entering the WWTP are estimated at 49 L/s (excluding Stockland at present

time). However, when SPS73 is connected to the 150 mm rising main and increases peak flows at

this pump station to 30 L/s (duty/assist operation), the total peak flows in 2021 could be as high as

78 L/s.

Effluent Disposal and Discharge Allowances

4.1.5 Recycled Water Users and Requirements The existing DA does not stipulate any nutrient or physical parameter limits and only indicates that relevant

guidelines should be adhered to for effluent disposal. No discharge to environment is allowed under this

licence.

A Recycled Water Management Plan (RWMP) and recycled water user agreements were collated in July

2013 to provide a framework for safe practice and use of effluent irrigation. The three main users are:

· Jimboomba WWTP onsite irrigation

· Hills Golf Course and College

· Adjacent horse paddocks

Of the three users, the onsite WWTP irrigation accounts for a comparatively minor amount of effluent

disposal.

The RWMP adopts limits outlined under Appendix 1 of the Recycled Water Exemption Guidelines. Key

critical and quality control points from the RWMP are outlined in Table 4-3.

Table 4-3: Jimboomba WWTP RWMP Critical and Quality Control Points and their respective critical limits and alert levels

Critical and Quality Control Points Critical Limits Alert Levels

E. coli count Water in the effluent storage pond: 1000 cfu/100mL*

Water leaving WWTP (outlet of chlorine contact tank): 100 cfu/100mL

Free chlorine residual (Minimum) Leaving WWTP (outlet of chlorine contact tank): 0.2 mg/L

Leaving WWTP (outlet of chlorine contact tank): 0.3 mg/L

Algal or cyanobacterial bloom 15,000 cells/mL Visual inspection results in suspicion of algal bloom

Free chlorine residual (Maximum) Leaving WWTP (outlet of chlorine contact tank): 2 mg/L

Leaving WWTP (outlet of chlorine contact tank): 1.7 mg/L

NB: * Equivalent Class C Recycled Water




According to the RWMP (July 2013):

If E.Coli levels reach the critical limit, the operator will inform each recycled water user and shut the

pumps off. The pumps will remain off until the chlorine residual and E.Coli levels are brought to within the

alert limits. The effluent storage lagoon will be used to hold the off-spec effluent.

In addition to on-line monitoring, the effluent lagoon is sampled for E.Coli on a weekly basis. If any

sample exceeds 1,000 cfu/100 mL, a follow-up sample is taken and the recycled water users are notified

of the possible exceedances.

Algae/cyanobacteria are sampled when a bloom is suspected. If the presence of algae is confirmed

(greater than 15,000 cells/mL), the recycled water users will be notified to suspend irrigation. Once

irrigation has ceased, the operator will manage the algal/cyanobacterial bloom at the effluent lagoon by

referring to the Jimboomba WWTP Lagoon Management Strategy (developed and managed by Logan

City Council).

As no nutrient indicators have been outlined in the DA or the RWMP, the effluent standards are expected to

be the same or better after any WWTP upgrades. Table 4-4 shows the performance of Jimboomba WWTP

from 2010 to 2013.

Table 4-4: Jimboomba WWTP TN and TP performance 2010-2013, including adopted upgrade limits

Year Total Nitrogen (mg/L) Total Phosphorus (mg/L)

Median Maximum Median Maximum

2010 10 23 8 10

2011 10 66* 8 13

2012 7 22 6 18

2013 9 28 7 11

Adopted Current Standard 10 30 8 20

NB: * Indicates that maximum during 2011 was during a period of biological inactivity, likely sludge wash-out, therefore not

adopted as current standards

An adopted median TN:TP of 10:8 (in mg/L) has been identified as the current standard of the WWTP. A

standard similar or better should be the basis for future upgrades.

4.1.6 Future DA negotiations – Lagoon Overflow Negotiations with DEHP are underway to include allowances for emergency lagoon overflow into the

adjacent Hendersons Creek.

Hendersons Creek experiences intermittent stream flows, primarily during wet weather events, and is

considered a sensitive receiving environment. The creek water level and flowrate increase quickly during a




wet weather event to velocities suitable for effluent dilution. Previous discussions between LCC and DEHP

have indicated lagoon effluent releases will not be allowed when the creek is not flowing.

Additional effluent release requirements from DEHP are anticipated, and may include zero negative impacts,

effluent TN/TP ratios and/or a creek dilution factor.

As this negotiation process is still in progress, uncertainties currently exist regarding the level of quality and

quantity of lagoon effluent allowed. For this reason, it is assumed that all upgrades should produce effluent

of similar standard to current performance (or better), and additional treatment will occur in the lagoon to

accommodate the future release limits.

External Constraining Factors Summary Based on an assessment of the future population projections and catchment pump capacities, the estimated

future maximum instantaneous flow in 2021 is 78 L/s, without pump flow rate control. The estimated

population in 2021 is 2,730 EP. Due to the CED systems in the catchment, this reduces to an equivalent to a

biological EP of 2,530 EP in 2021. The corresponding PWWF flow is approximately 35 L/s.

Although there are no quality limits in the existing DA, it is expected that any upgrades should produce

effluent similar or better than the current standards. A future DA is under negotiation which will allow release

to an intermittently-flowing creek; however, the quality and quantity allowances are still uncertain.

The Jimboomba WWTP RWMP states critical and quality control limits to form guidelines that protect

environment and public health with the practice of effluent irrigation to recycled water users. The RWMP

includes values for:

· The effluent leaving the WWTP:

o alert limits of 1.7 mg/L and critical limit of 2 mg/L maximum free chlorine

o alert limit 100 cfu/100 mL E. Coli

· Effluent in the lagoon:

o critical limit of 1000 cfu/100 mL E. Coli

o alert limit of no visual inspection of blue-green algae

o critical limit of 15,000 cells/100 mL of blue-green algae.

All upgrades should adhere to the alert limits of the effluent leaving the WWTP, as best as practical.




5. EXISTING WWTP CAPACITY AND PERFORMANCE

WWTP Overview The Jimboomba WWTP consists of an inlet works with coarse screening, a continuously fed, intermittently

decanted sequencing batch reactor (SBR), a chlorine contact tank (CCT), and an 18 ML recycled water

storage lagoon. The site also has two sludge lagoons and onsite sludge dewatering facility. The treatment

plant is producing Class C effluent after the effluent storage lagoon, which is distributed to recycled water

users via their private infrastructure. Figure 5-1 shows an overview of the WWTP.

Figure 5-1: Jimboomba WWTP Aerial View

Hydraulic Assessment

5.1.1 Hydraulic Infrastructure The WWTP is a gravity flow system, and was designed to use the natural slope of the site to maintain gravity

flow throughout the plant, thus requiring no lift pumps within the plant itself. Figure 5-2 shows a schematic of

the infrastructure connectivity.




Figure 5-2: Jimboomba WWTP Infrastructure Schematic

The WWTP process involves:

· Rising mains from the catchment pump stations transfer inflows to the plant via the two receiving

manholes. External inflows combined with small site flows (including sludge lagoon supernatant (or

overflow) and sludge dewatering filtrate) gravitate to the inlet screen pit

· Screened flows gravitate to the SBR continuously. The mechanically controlled weir slowly lowers at

the end of a treatment cycle to decant flows into the decant pit

· Flows from the SBR are transferred to the chlorine contact tank (CCT) via a flowmeter and control

valve, throttled to 31L/s to ensure an appropriate hydraulic retention time (HRT) within the CCT

· Flows from the fixed CCT outlet weir enter the gravity main, and flow to the effluent storage lagoon.

The SBR contains a large inlet baffle for redirecting inflows to the tank floor, aeration equipment for biological

treatment and wasting equipment for excess sludge removal. The SBR currently operates on a 4.8 hour

cycle, with 80 minutes decant time and an average decant flowrate of 19 L/s (plus WWTP inflows). The 17 kL

CCT has a HRT of 82 minutes during ADWF, or 9 minutes at limited flow of 31 L/s. Plant recycled water

offtakes and pumps are located near the outlet of the CCT. There is no wet weather bypass.

Key hydraulic WWTP infrastructure and their capacity limitations are summarised in the following table.




Table 5-1: WWTP key infrastructure and their capacities

5.1.2 Observed Hydraulic Performance Observed performance during operation of the WWTP has been used in part to verify the hydraulic

modelling:

· The weir was observed to be submerged during normal operation decant, and does not appear to lower its full 0.6m design level to horizontal or beyond

· During the March 2014 storm event, the WWTP received its highest daily flow of 1027kL, including a continuous maximum pumped flow from SPS 73 and 74 simultaneously (37L/s) over a 3 hour period, plus flows from private pump stations, though duration and frequency cannot be verified. Ongoing high flows resulted in the WWTP inlet pit and upstream infrastructure surcharging and overflowing at the lowest available point, filling Sludge Lagoon 2 with raw wastewater

· On multiple occasions, high pumped flowrates above 30L/s have been observed by LCC operators to scour out the MLSS (sludge) from the SBR

· The inlet screen pit has been observed to reach over 90% full on a number of occasions since the connection of SPS74 to its new rising main in August 2013. The 13th and 24th November 2013 occurrences are additionally observed through inlet pit level data analysis. Additionally, SCADA data indicated a high number of pump runs for SPS73 and 74 at this time, with some combined duty and standby pump runs, though simultaneous pump runs were not verified.

WWTP component Size Capacity

Pipes 225 dia.

24L/s at 75% full (min grade) 26L/s at 100% full (min grade)

300 dia.

44L/s at 75% full (min grade) 48L/s at 100% full (min grade)

Inlet Screen and Pit Pit is 1kL Observed. 37+L/s

Screen is 20mm spaced 15mm coarse bar

SBR

618kL 17 x 12 x 4m

operating volume 92kL

Observed 30+L/s

SBR Weir 3m wide, 0.45m operating depth

SBR Decant Pit

1kL 3.2 x 0.75 x 1.5

Flowmeter and throttling valve 300 dia. Set to 31 L/s

CCT

17kL 22 x 0.7 x 1.6m

31L/s HRT of 9 mins

CCT weir and pit

0.7m slight v notch concrete weir 0.6kL

0.5 x 0.7 x 1.6m

Lagoon 18ML 18ML 0.5m freeboard




5.1.3 Hydraulic Modelling Outcomes Hydraulic modelling (via a simple excel model) was used to estimate hydraulic performance and key

constraints at nominated flowrates. Modelling was undertaken for both throttled and free flows using the two

scenarios SBR full, and SBR after decant, and assumes no losses at any point in the system. The model has

been aligned with known hydraulic data, however, is not calibrated, and should only be used as a guide. The

results of the model are included in the following table.

Table 5-2: Indicative outcomes of simplstic hydraulic modelling

Asset Surcharge Insufficient Freeboard Overflow

SBR - n/a - around 60L/s - around 100L/s

CCT - n/a - around 35L/s - around 100L/s

CCT Effluent Main - above 40L/s - manhole - around 100L/s - around 100L/s

Inlet Pit - n/a - around 50 L/s - around 60L/s - (around 50 L/s with increased

blinding of screen)

Influent Mains - pipes – around 30L/s - manholes - around 30L/s - manholes - around 40L/s

- sludge lagoon connection – over 36L/s

- manhole near sludge lagoon - around 50L/s

- other manholes - above 55L/s

At inflows at approximately 50 L/s, the sludge lagoon connection and adjacent manhole are likely to be

overflowing, with inlet pits and upstream infrastructure surcharged. Without throttled flow; the CCT is above

its freeboard level. In addition, headloss reduction of around 50% across the inlet screen pit would reduce

the risk of overflows from upstream manholes, though the sludge lagoon connection may still overflow at

inflows above 50 L/s (when the screen blinding factor is decreased from 90% to 70%).

The analysis indicates that the SBR is theoretically above its hydraulic capacity at around 60 L/s, and the

CCT at around 35 L/s, though the CCT effluent main and manhole are only likely to spill for flows above

100 L/s. The inlet screen pit and upstream pipework has hydraulic limitations that need to be considered

when developing solutions, especially for managing the sludge lagoon connections and system surcharging.

Biological Assessment A detailed assessment of the current performance of the WWTP (Hartley, 2013 – refer to Appendix C)

concluded summary of the assessment concluded that:

· The design capacity of the current SBR is 1,500 EP

· The estimated population in 2013 is 1,100 to 1,200 EP based on BOD loads and accounting for the

CED systems in the catchment (assuming 25% reduction in BOD)




· From July 2011 to September 2013, the effluent quality was:

o Median TN and TP concentrations were 8.8 mg/L and 7.1 mg/L, respectively, whereas

maximum concentrations during this period were 66 mg/L and 18 mg/L

o Median E. Coli was <1 cfu/100 mL and 95th percentile was 56 cfu/100 mL

o Median free chlorine residual was 0.4 mg/L and maximum was 2.1 mg/L

· In general, the performance showed that:

o Effluent BOD and SS were low except for high flow periods where significant solids

carryover occurred during decanting

o Nitrogen removal was performing as exhibited by median effluent ammonia-N and TN

concentrations of 0.6 mg/L and 8.8 mg/L

o No enhanced biological P removal was occurring, as the median effluent TP was 7.1mg/L

o Chlorination was effective

Anecdotal evidence from operators indicates that solids carryover occurs above approximately 31L/s to

34L/s. This is limited to the weir length, which is a contributing factor to sludge blanket scouring when

considering the weir approach velocity.

The key bottlenecks in the continuous SBR system that limit the plant to 1,500 EP are the tank operating

volume, the aeration capacity and the operating cycle time.

The CCT is performing at the current dry weather flows, producing Class B recycled water from the outlet of

the CCTs. The current peak flow hydraulic retention time (HRT) for the CCTs is 9 minutes. The operators

have limited the flow upstream of the CCT, by reducing a valve to 31 L/s.

WWTP Capacity Based on the hydraulic and biological assessments, the Jimboomba WWTP has a capacity of approximately

1,500 EP and is limited to a flow of 30 L/s in the SBR. The inlet pit and upstream pipework are currently

constrained at approximately 35 L/s, and the CCT at 31L/s (for adequate treatment).

Figure 5-3 shows the predicted loads and current capacity of the WWTP. According to the estimates, the

biological capacity will be reached by 2015; however, actual flows and loads indicate development in the

catchment is slightly lower than the theoretical EP predictions. An effluent water quality analysis indicates the

plant is currently able to effectively treat inflows, except during significant peak inflow (wet weather) events.




Figure 5-3: Jimboomba WWTP Future Loads and Current Capacity

Peak wet weather flows are received at the plant as pumped flows, and the current peak pump flow capacity

of 49 L/s maximum instantaneous flow is substantially higher than the 2021 PWWF estimate of 35 L/s, due

to current operating parameters (no VSD or system flow controls). This pumping capacity also allows high

flows from extreme wet weather events to be pumped continuously to the plant, effectively flooding the plant,

washing out MLSS, and contaminating the effluent lagoon. This impacts the treatment performance for

around the next one to two weeks.

Based on the assessment, hydraulic upgrades for Jimboomba WWTP are required as soon as practical, with

biological upgrades required by 2016 to maintain discharge requirements (subject to realised growth rates

and treatment plant performance).

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Biol

ogic

al L

OAD

EP

Jimboomba WWTP - Predicted Loads and Current Capacity

Biological EP:

WWTP biological capacity (EP)

PWWF (L/s)

Hydraulic Capacity (L/s)




6. PRELIMINARY OPTIONS DEVELOPMENT This section provides a brief overview of the preliminary options development prior to determining detailed

options for further investigation and analysis.

Upgrade Requirements Table 6-1 shows the adopted upgrade requirements for the Jimboomba WWTP in different areas of the

WWTP based on the constraining factors and current WWTP capacity.

Table 6-1: Upgrade Requirements for Jimboomba WWTP

Catchment Inlet Works Biological Process Chlorine Contact Tanks

Capacity at 2021 with no upgrade 78 L/s 35 – 40 L/s 30 L/s 1500 EP 3 min HRT (at

peak flow)

Requirement for Upgrade

<78 L/s flow based on upstream pump station flow management

2530 EP or greater

9 min HRT or greater (at peak

flow in 2021)

All final options will be developed to accommodate the required capacity to meet the future projections in

2021 (assumed year for Cedar Grove WWTP diversion).

Preliminary Options

6.1.1 Pumped Flow Management Managing the flows reaching the WWTP is a simple effective measure to reduce the hydraulic impacts

currently being experienced at the WWTP. Options to reduce the WWTP pumped inflow include:

1. Do nothing

2. Delaying connection of SPS73 to the 150 mm dia. rising main (limiting flow from this SPS to 6.5 L/s

until diversion through the new rising main)

3. Restrict pump operation at SPS74 (and SPS73 in future) to a Duty/Standby arrangement

4. Implement systemic control to ensure that only one key pump station can operate at the one time

(though this restriction will be overridden if the pump stations are close to overflow as per operation

licence requirements)

5. Implement VSD controls to limit pumping flow rates at SPS73 and SPS74. This requires

consideration of minimum velocity requirements

Apart from the do nothing scenario, all options were considered for implementation in order to reduce peak

flows entering the WWTP as best as practicable.

VSDs have been installed at SPS 73 and SPS74; however; have not been commissioned. A review of the

system curve for both pump stations indicates that VSD-controlled reduction is within the feasible range,




though this will need verification onsite to ensure effective solids lifting. In addition, the pumps may need to

run at full speed for a very short time on a regular cycle (i.e. once a day) to maintain operability.

In addition, system controls currently being rolled out across the LCC network should be implemented in this

catchment to manage dry weather pumping peaks that are reaching the WWTP, to reduce simultaneous

pumping flow impacts on the WWTP process and regulating the plant inflows.

To limit immediate peak flow impacts, the SPS73 future 150 mm main should not be connected until SCADA

data indicates pump station overflow events (or high risk of overflow) during reasonable storm events.

Current SCADA data indicates SPS73 has not been overflowing in recent years, including the large March

2014 storm event.

Based on the status of the existing Jimboomba WWTP and the potential upgrade of the plant to

accommodate future growth and network constraints out to 2021, network capacity needs to be considered

in two stages. These stages include:

· Stage A Existing – Consideration needs to be given to the capacity constraints of the existing plant

to ensure its effective operation up to the resolution of the WWTP capacity constraints

· Stage B Future – Based on current network assets and catchment growth, a suitable capacity

constraint needs to be established for consideration in the development of Jimboomba WWTP

capacity options

Table 6-2 shows the proposed pump station strategies for pre and post WWTP upgrade. These strategies

are compared to do nothing estimates for the existing and future network configurations. Refer to Appendix B

for more detailed information.

Table 6-2: Upstream pump controls and resulting maximum WWTP inflow rates

Option Existing (do nothing)

Future (do nothing)

Stage A Existing (pre WWTP upgrade and commissioning period)

Stage B Future (post WWTP upgrade)

SPS 73 7 30 7 17.3

SPS 74 29.7 29.7 17.3 19.6

Hills College 8.3 8.3 8.3 8.3 Johanna St Child Care 4 4 4 4

Stockland - 6 4.5 4.5

Total (L/s) 49 78 Up to 34.1 53.7

Comment · Impacts WWTP

· Impacts WWTP

· Systemic control between SPS73 and SPS74

· VSD control · Delay SPS73 connection · Reduce Stockland PPS to

minimum velocity · Total flows reduced to

29.6 L/s if Stockland connection is delayed

· No systemic control required

· VSD control · Reduce Stockland

PPS to minimum velocity




If systemic and VSD control is implemented in the short-term (i.e. Stage A), the maximum flow rate reaching

Jimboomba WWTP is estimated as 34.1 L/s. This is likely to cause some process issues at the WWTP if

sustained for long pumping periods. To avoid process issues at the WWTP, the flow may be reduced further

to 29.6 L/s if Stockland connection is delayed until after any WWTP upgrades.

Upgrade options for the Jimboomba WWTP should consider 53.7 L/s as an appropriate capacity (i.e. Stage

B). However, this assumes some form of restrictions can be achieved in terms of flows received from private

pump stations, with the Stockland pump station as a prime candidate.

6.1.2 Inlet Works and Associated Considerations Inlet screen capacity

The current inlet works consist of a manually-cleaned 20 mm bar screen located within a small 1 kL concrete

pit. At times, the inlet pit is known to temporarily surcharge to over 90% full, though has not yet spilt from this

location (as per the inlet pit level sensor data 2013-14 provided by LCC).

A recent storm event in March 2014 flooded the inlet works and backed up raw wastewater into one sludge

holding lagoon, which was partially empty at the time of the event. The hydraulic assessment has indicated a

capacity of approximately 35 L/s upstream of the SBR, due to a combination of constraints including the inlet

screen and pit, associated upstream and downstream pipework and the sludge lagoon inflow connection.

With flow management control in the catchment pump stations, the maximum flow can be reduced to

maximum instantaneous peaks of approximately 54 L/s prior to diversion of flows to the proposed Cedar

Grove WWTP, which far in excess of the 35 L/s capacity. As such, the inlet works requires an upgrade.

Upgrade considerations have been limited to fine screening and increasing the inlet works capacity to

accommodate peaks prior to screening. Fine screening is preferred over the current bar screens, as this will

help improve ragging entering the SBR and protect the operating assets. The two types of fine screening

units considered were a sieve screw screen or a step screen. The step screen was discounted due to

associated difficulties with installing screens within a retrofitted inlet works and the requirement of a long

approach channel. The sieve screw screen has been successfully operated at the Flagstone WWTP and

therefore has been adopted for the purposes of this planning study. The screen will have the capacity to treat

54 L/s and have appropriate overflow in the case where the screen fails.

The inlet works pit volume should be increased appropriately to allow for reasonable instantaneous flow

fluctuation upstream of the sieve screw screen. The screen and pit should be designed to minimise headloss

and potentially overflow to storage, to assist in avoiding wastewater backing up to the sludge lagoons, or

overflowing from the adjacent manhole. Automated valves should also be installed in the inlets to the sludge

lagoons to protect overflow into the lagoons.

The inlet works upgrade will be applied across all options.




Flow Monitoring Considerations

The WWTP currently has no control of the pumped flows that enter via the catchment. Flow monitoring is

available in the new connection of SPS74 but is not yet available for SPS73 until it is connected to its new

rising main. There is no control or monitoring of current private pump stations (Hills College and Johanna

Road Child Care Centre). Figure 6-1 shows the current flow monitoring arrangement.

The ideal flow monitoring arrangement to ensure all external instantaneous flows can be monitored at the

plant, is upstream of the inlet works collection manhole as indicted in Figure 6-1. This flow monitoring

upgrade will be applied across all options.

Figure 6-1: Jimboomba WWTP Pump Station Connection points with Current and Proposed flow Monitoring

6.1.3 Treatment Process Options Considerations Treatment process hydraulic and biological considerations result in a 30 L/s limitation, with any higher

instantaneous flows likely to cause settled sludge blanket uplift (i.e. sludge blanket scour) and may cause

solids loss in the SBR. This flow rate corresponds to the WWTP design capacity of 1,500 EP.

Any process upgrades of the SBR will need to be sufficient to cater for peak instantaneous flows of 54 L/s

(managed pump station flows) and average dry weather loads from 2,530 EP (the projected population

estimates for 2021).




Hydraulic Upgrade Options

Potential hydraulic upgrade options could include:

· Upstream balance tank

· Wet weather bypass

· Increasing plant capacity.

Assuming upstream pump station flow management is implemented, all options will be required to

accommodate 54 L/s instantaneous flows.

Hydraulic constraints could be simply resolved through duplicating the biological treatment process train.

Increasing the plant capacity would require a parallel process train of at least 22 L/s, to limit the capacity in

the existing SBR to 30 L/s and avoid sludge blanket scouring. Several process options are available and are

discussed in the biological upgrade option section.

Flow balancing with upstream balance tanks could reduce or possibly avoid the requirement to upgrade the

SBR, and provide a near steady flow of waste water through the SBR, allowing for consistent treatment at

the plant. Flow balancing options include storage of temporarily high flows within:

· Small overflow balance tank at the inlet screen (post processing) to cater for instantaneous peak

flows during dry weather

· Large overflow balance tank at the inlet screen (post processing) to cater for all wet weather flows

· Multiple balance tanks throughout the treatment process which could mitigate the various sections of

hydraulic restrictions within the current system

Installing multiple balance tanks throughout the treatment process would have hydraulic constraints and

complicate the process, which could effectively be mitigated with a balance tank at the inlet works.

A wet weather bypass located at the inlet works could avoid the need for upgrading the hydraulic capacity of

the existing WWTP. Potential bypass options include:

· Bypass SBR only, super chlorinate at CCT

· Bypass SBR and CCT

· Bypass to separate storage, with intention of return to SBR for treatment (e.g. divided lagoon)

· Bypass to Hendersons Creek

· Bypass to Logan River

Any bypassing to local waterways would require a DA licence amendment. LCC Environment Management

officers have identified that discharge of ‘untreated wastewater’ to Hendersons Creek would not be viewed

favourably by DEHP. The current DA stipulates zero effluent discharge to the environment. Bypassing to

local waterways is not considered viable. A segmented portion of the storage lagoon is not ideal as raw




wastewater would be regularly drained to the lagoon is small amounts and the cost would be significantly

higher to pump the flows back to the WWTP than a balance tank at the inlet works. The options for further

consideration are the bypass options within the WWTP and do not discharge to the environment directly.

These would still require an amendment to the DA.

Biological Upgrade Options

Potential biological upgrade options include:

· Do nothing (shut down WWTP during peak flows)

· Sequential upgrade of the existing SBR process

· Upgrade SBR process to MBR process

· Install parallel package plant

· Install parallel SBR plant

· Transfer flows to Flagstone WWTP

The Do Nothing option would not resolve anticipated biological capacity issues at the WWTP that will result

from the projected contributing population increase. As such, the WWTP capability to remove nutrients and

produce ‘Class C’ recycled water will become compromised in the near future and would result in

proliferating algal blooms in the effluent lagoon and hinder the ability to supply recycled water to agreed

customers. The Do Nothing approach will only be considered suitable only if minimal growth is experienced

within the catchment prior to the construction of the Cedar Grove WWTP (currently scheduled for 2021).

Sequentially upgrading the existing SBR process would involve a staged approach to increase biological

capacity based on an assessment of the existing SBR (see Appendix C). Stage 1 would involve increasing

the biological capacity from 1,500 EP to 2,100 EP, with Stage 2 further increasing the biological capacity to

2,600 EP. Required works involve increasing the existing SBR wall height by 225 mm, modifying cycle times

and increasing the decanter weir length from 3 metres to 6 metres.

The option to upgrade the SBR process to an MBR process was assessed as part of the Jimboomba WWTP

Upgrade Project Development Task (LWA Task No: 90-10-87-001, November 2011) and will not be

progressed further as part of this current study. The capital cost was estimated at approximately $6.1m

(2011$) and would provide high quality ‘Class A’ recycled water when only ‘Class C’ standards are required.

The option to transfer flows to the Flagstone WWTP would initiate an appropriate upgrade at the Flagstone

WWTP to accommodate these flows. The transfer main will not be in alignment with the future Cedar Grove

WWTP transfer main and is expected to cost $5m to $10m.

The options considered viable for further analysis are the parallel package plants and duplicating the SBR

plant. These options will provide both hydraulic and biological upgrade requirements to cater for growth and

flows until 2021.




6.1.4 Chlorine Contact Tank Options The current CCT has a 9 minute hydraulic retention time (HRT) during peak flow periods at the current

population levels. The HRT would reduce to 3 minutes with the current tank volume at the projected

populations, adjusted operations and flows in 2021.

Based on the RWMP (2013), the critical limit for maximum free chlorine from the WWTP is 2 mg/L and the

alert limit is 1.7 mg/L, which would not be met with the reduced HRT.

Potential chlorination options include:

· Increasing the CCT volume

· Install upstream flow balancing tank

· Superchlorination (and appropriate dechlorination if necessary)

Based on the projected peak flows and expected SBR mode of operation (which has a limited decant period

as opposed to continuous operation), the ultimate peak flow through the CCTs is estimated at 95 L/s for the

2021 projected population and flow. A 3 minute HRT is not expected to produce consistent disinfection

requirements during peak flows and therefore the CCT volume should be tripled to account for population

projections at 2021. This will achieve a 9 minute HRT with a free chlorine residual of 1.5 mg/L.

Another viable option is to install upstream flow balancing, to be situated between the SBR and the CCTs.

This will effectively balance the flows and produce a more continuous operation, which will reduce the

capacity requirement. A 260 kL tank (Hartley, 2009) would be required with associated pumping (as the

hydraulics would not be sufficient to promote complete gravity flow). The balance tank option would prove

more expensive than increasing the CCTs to 51 kL.

Another option is to superchlorinate the flows and dechlorinate if appropriate. Without dechlorination, the

discharge will be greater than the 2 mg/L limit, (with a 2.3 mg/L free chlorine residual if the chlorine tanks

were doubled in size). A 3 minute HRT is not considered sufficient lag period for disinfection, even with

dechlorination and therefore this option was discounted.

The option to upgrade the CCTs to 51 kL will be applied across all options, except where a parallel package

plant duplication is installed. This would reduce the upgrade requirement to 43 kL due to its continuous

operation.

Preliminary Options Workshop Outcomes A preliminary options workshop was held at Jimboomba WWTP on 5th February 2014 and included the LWA

and key LCC stakeholders.

Table 6-3 outlines the preliminary options discussed in the workshop for hydraulic and biological upgrade, as

well as catchment control options.




Table 6-3: Preliminary Options Workshop Options Overview

Hydraulic Upgrade Preliminary Options* Biological Upgrade Preliminary Options ** Catchment Control Options WWTP Infrastructure Options

a) Do nothing

b) Pump Station Flow Pacing

(VSD controlled)

c) Sequencing Pump Stations for

systemic control

a) Do nothing

b) Flow Balancing – balance

tank

c) Wet weather bypass and

treatment plant licence

amendment

d) Increase WWTP capacity

a) Do nothing

b) Sequential upgrade of the

existing SBR process

c) Upgrade SBR process to

MBR process

d) Add parallel package plant

e) Add parallel SBR plant

f) Transfer flows to Flagstone

WWTP

NB: * Each option can be applied separately or in combination to obtain the required hydraulic flowrate. ** Options are unlikely to be viable in combination with other biological upgrade options, however will be implemented with one or more of the hydraulic upgrade options. Outcomes of the workshop are as follows:

· The do nothing option was considered unacceptable as a biological or hydraulic option

· Flow balancing of upstream pump controls should be applied to all options, though the hydraulic capacity must be able to manage maximum pumped flow without spilling (in case controls fail)

· Transfer to Flagstone WWTP is discounted as it is too far away, with an expected cost of around $5m to $10m for infrastructure that is not in alignment for the future Cedar Grove transfer pipeline

· Wet weather treatment bypass will be problematic, as it will impact the upcoming DEHP operating license negotiations for wet weather release to Hendersons Creek from the effluent storage lagoon, but should be pursued

· Altering the existing operation philosophy to intentionally create treatment short circuiting may also be problematic regarding DEHP negotiations, however should be pursued

· Upgrading the SBR to MBR process should not be considered further, as it has previously been proven to be a significantly higher cost.

Options for Further Development The following detailed options were developed from the preliminary options:

· Option 1 – Upgrade the SBR and install a Peak Instantaneous Flows Balancing Tank

· Option 2 – Upgrade the SBR and install a Wet Weather Balancing Tank

· Option 3 – Upgrade the SBR and install a Wet Weather Bypass to CCT

· Option 4 – Duplicate the SBR

· Option 5 – Install a Parallel Package Plant




Discounted inclusions

These options were developed using a matrix for combining the hydraulic and biological solutions,

determining which solutions meet the treatment and planning criteria (refer to Appendix D for more detail).

The options were reviewed by the LCC Operations Supervisor to remove higher operational risk. The

outcomes of this process, resulted in the following inclusion being discounted from the options due to high

risks or not meeting the planning and treatment discharge criteria:

· Wet weather bypass of the plant (to CCT outlet, Hendersons Creek or Logan River) was discounted

due to the potential impact on the lagoon (including increased nutrients and algae blooms), and/or

receiving waters. Accessibility issues, easement acquisition and significant infrastructure

requirements deterred the Logan River option

· Use of the existing effluent lagoon to store wet weather flows (with divide wall and return pump) was

discounted due to the wet weather storage complications and overflow risks, and the time required to

treat (or retreat ) the separated lagoon waters

· Undertaking an SBR upgrade without a peak instantaneous flow balance tank would risk sludge

washout during normal to high flow operation conditions.

· No controlled pumping, due to the additional hydraulic capacity of 46 L/s (from 22 L/s), effectively

doubles the managed wet weather volume (and instantaneous pumped flow volume).

Common inclusions

A number of inclusions were considered common to all options:

· System pump controls (VSD and systemic) with appropriate overflow from PS overflow location and

sufficient flow monitoring

· Hydraulic Upgrade:

· Inlet screen upgrade with sieve screw screen

· Sludge lagoon overflow valves

· Biological Upgrade:

· CCT upgrade (51kL)

· Chlorine dosing system upgrade

· Alum dosing system upgrade pH dosing system




Table 6-4: Overview of Developed Upgrade Options for Further Analysis

Catchment Inlet Works Treatment Process Chlorine Contact Tanks

Constraint Maximum of 78 L/s 35 L/s 30 L/s 1,500 EP 3 min HRT at peak flow in 2021

Adopted Requirement for Upgrade Maximum of 54 L/s 2,530 EP or better 9 min HRT at peak flow in 2021

Option 1

Pump station VSD commissioning*

Upgrade inlet works and install fine screening**

Instantaneous flow balance tank Upgrade SBR (raise

walls, increase aeration capacity,

extend weir length, modify cycle times) Upgrade CCT volume

Option 2 Wet weather flow balance tank

Option 3 Wet weather bypass to CCTs

Option 4 Duplicate SBR

Option 5 Parallel Package Plant

NB: * Operation to include overflow at SPS 73 and SPS74 above 6.5 x ADWF as per DA allowance

** Flow monitoring to be applied at upstream manhole




7. DETAILED OPTION ANALYSIS

Option 1 – Upgrade SBR and Peak Instantaneous Flows Balancing Tank Option 1 involves installing a 30 kL balancing tank adjacent to an upgraded inlet works, and upgrading the

existing SBR capacity. The small balancing tank will cater for peak instantaneous flows during dry weather

and consist of an overflow into the SBR when its capacity is reached. The balancing tank will protect the

treatment process by maintaining flows below 30 L/s The SBR will be upgraded to a 2,600 EP capacity,

therefore meeting the projection load requirements of 2,530 EP through upgrades to the tank capacity, weir

length and aeration capacity. The inlet works and CCTs will be upgraded as per all options.

Option 1 incorporates the following works (Table 7-1), to meet a population of 2,600 EP and a maximum

instantaneous flow capacity of 54 L/s.

Table 7-1: Option 1 - Description of Works

Stage Description of Work New Capacity Trigger for Work

1

· Install small storage tank, pump and overflow to SBR · Increase decanter length from 3 metres to 6 metres and

raise by 225mm · Raise SBR walls by 225mm · Common hydraulic upgrade – Inlet works and sludge

lagoon overflow valves

54 L/s hydraulic capacity upgrade

>30L/s pumped flow to plant – required now

2

· Increase aeration capacity · Upgrade of aeration and decanting controls · Upgrade electrical switchboard and building · Reduction of SBR operation cycle to 3 hours (from 4.8hrs) · Common biological upgrade works

2,600 EP biological capacity

1,500 EP biological capacity (CED

adjusted) – required nominally

2016

The small balance tank would smooth the instantaneous peak pumped flows of 54L/s, returning flows to the

inlet works. The new weirs would double the overall length, allowing for additional decant volume without

sludge scouring, and the wall height extension is also completed at this time.

With the increased treatment and decant volume, an aeration capacity increase, and control upgrade

increase for the loading treated, a reduced cycle time would be adopted, allowing for more treatment batches

per day. The CCT and dosing equipment would be upgraded to accommodate the increased treatment

volume.

The SBR upgrade requirements were previously determined by K. Hartley; however, the scheduling of works

has been modified to accommodate the urgent hydraulic capacity improvements.

Modelling was undertaken to verify the balance tank volume. A minimum 26 kL tank is sufficient for most

scenarios, based on 3hrs. at constant LCC pumping, with variation of set duration of 10 minutes and variable

pumping for the private pump stations: the Hills and Stockland pumps running ¾ of the time (30 min in 40

minute cycle) and the Child Care Centre pumps running a quarter of the time (10 minutes in 40minute cycle).




A 30kL tank is currently available and unused by LCC, and sufficient to manage excess flows for 20 minutes

under continuous 54L/s pumped flows, or 30 minutes for reduced private pump station flow.

Capital Cost Estimate

The following table shows the staged capital cost estimate for Option 1.

Table 7-2: Option 1 – Capital Cost Estimate, Staging and Schedule

Stage Description of Work Capital Cost Estimate (2014 $) Scheduled

1

Inlet works and sludge lagoon valves Small storage tank, pump and overflow to SBR Upgrade SBR weirs and walls - New weirs and pits, raise SBR walls 225mm Minor electrical and SCADA work

$949,000 2014/15

2

Biological upgrade – aeration system upgrade Chlorine Contact tank duplication Chemical dosing upgrade Electrical switchboard, and building (electrical or blower) upgrade Minor electrical and SCADA work

$1,468,000 2016/17*

Total $2,417,000

* biological upgrade requirement assumed to be delayed to 2016/17 as per current population estimate, to be verified

against new IDM.

All works should be designed together, to ensure hydraulic issues are consistently resolved. Project cost

efficiencies may outweigh the delayed investment for Stage 2 by undertaking a combined construction works

package, given the short period between required works.

Benefits and Risks The benefits/advantages and risks/disadvantages of this option are listed in the following table:

Table 7-3: Option 1 – Benefits and Disadvantages

Advantages and Benefits Disadvantages and Risks

§ Works can be staged to accommodate delayed biological load/ catchment growth

§ The existing SBR is fully utilised to beyond its original capacity

§ The small tank and inlet works can be implemented as soon as the design is finished (original funding in 2013/14)

§ There is less infrastructure than other options (no wet weather infrastructure)

§ Hydraulic constraints are significant and restrictive for design of the inlet screen pit and small balance tank

§ The inlet screen pit is submerged as the increased TWL of the SBR is above the inlet pit IL

§ The plant is dependent on upgraded SBR to accommodate wet weather flows. The risk of sludge overflow due to high inflows is still present, though reduced to flows above 44L/s for an extended period

§ The risk of compromised treatment quality is present, as the reduced treatment time and increased volume per cycle may not be as effective, or have resilience for treatment spikes, additional loading or environmental changes.

§ The change of process at high flows is disruptive to the treatment process and cycle timing

§ Biological upgrade is not staged, 2600EP is implemented as one stage

§ There is no further upgrade potential on the SBR § Works need to occur on an operating plant – there is

no option for diversion or shutdowns




Figure 7-1: Option 1 Infrastructure Schematic




Option 2 – Upgrade SBR and Wet Weather Balancing Tank Option 2 involves installing a 250 kL wet weather balancing tank adjacent to the proposed new inlet works

and upgrading the existing SBR capacity. The wet weather balancing tank will cater for peak instantaneous

flows during dry weather periods and be able to contain wet weather peak flows, pumping the excess flows

through the treatment process when flows have subsided. This option will protect the treatment process by

maintaining below 30 L/s. The SBR will be upgraded to a 2,600 EP capacity, therefore meeting the projection

load requirements of 2,530 EP through upgrades to the tank capacity, weir length and aeration capacity. The

inlet works and CCTs will be upgraded as per all options.

Option 2 incorporates the following works (in Table 7-4), across three stages to firstly meet a 54 L/s

instantaneous flow capacity, then a population of 2,100EP and finally 2,600EP.



1 Install 250kL storage tank, pump and overflow to SBR Common hydraulic upgrade – Inlet works and sludge lagoon overflow valves



2

Increase aeration capacity Upgrade of aeration and decanting controls Upgrade electrical switchboard and building Reduction of SBR operation cycle to 3 hours (from 4.8hrs) Common biological upgrade – pH and alum dosing only

2,100EP biological capacity



2016

3

Increase decanter length from 3 metres to 6 metres and raise by 225mm Raise SBR walls by 225mm Common biological upgrade works – CCT tank and chlorine dosing only




2018

The large balance tank will cater for wet weather flows in addition to smoothing out the instantaneous peak

pumped flows of 54 L/s during dry weather periods.

The SBR upgrade requirements were previously determined by K. Hartley and are the same as for Option 1,

though timing of the hydraulic component is able to be delayed due to the large balance tank. The aeration

capacity and control upgrade increase the biological load treated per batch, with the reduced cycle time

allowing for more treatment batches per day so as to meet 2100EP biological capacity. To meet 2600EP

biological capacity, the wall and weir increase at the SBR is required for treatment capacity increase (to

increase volume treated per cycle) and decant volume increase.

The CCT and chlorine dosing also required upgrading to accommodate the increased treatment volumes.

The 250kL balancing tank is sized to meet 8 hrs of constant 54 L/s pumping (for a future SBR capacity of 44

L/s), and 3hrs constant pumping for the existing SBR. In addition, the large tank is also sized to meet 70% of

PDF (peak day flow) in 12hrs, 50% of PDF in 8 hrs and 30% of PDF in 4 hrs, where PDF is the maximum

plant inflows of 1027 ML/d (received 28 March 2014) escalated to 2021 volumes.








1 Inlet works and sludge lagoon valves 250kL storage tank, pump and overflow to SBR Minor electrical and SCADA work

$419,000 2014/15

2

Increase aeration capacity Upgrade of aeration and decanting controls Chemical dosing upgrade – pH and alum dosing Electrical switchboard, and building (electrical or blower) upgrade Minor electrical and SCADA work

$1,139,000 2016/17*

3

SBR weirs and walls - New weirs and pits, raise SBR walls 225mm Chemical dosing upgrade – chlorine dosing only Chlorine Contact tank duplication Minor electrical and SCADA work

$1,066,000 2017/18

Total $2,624,000

* biological upgrade requirement assumed to be delayed to 2015/16 as per current population estimate, to be verified against new IDM.

All works should be designed together to ensure hydraulic issues are consistently resolved. Inlet works

should be installed as soon as the design is completed and funding permits, preferably before the 2014/15

wet season.

A Stage 3 Biological upgrade will be required when the plant biological load reaches 2,100EP, currently

expected in 2017/8.

Project cost efficiencies may outweigh a delayed investment approach if the biological upgrade installation

work (Stage 2 only, or Stage 2 and 3) is delivered with the hydraulic upgrade (Stage 1) as a combined

construction works package.

Benefits and Risks The benefits/advantages and risks/disadvantages of this option are listed in the following table:

Table 7-6: Option 2 – Benefits and Disadvantages Advantages and Benefits Disadvantages and Risks

§ Works are staged to accommodate delayed biological load/ catchment growth


§ The inlet works can be implemented as soon as the design is finished (original funding in 2013/14)

§ The large storage tank will allow for storage of over 1 day at ADWF, allowing shut down of the SBR for maintenance or capital works.

§ Hydraulic constraints are significant and restrictive for design of the inlet screen pit and large balance tank

§ The inlet screen pit is submerged near the end of each treatment cycle as the increased TWL of the SBR is above the inlet pit IL

§ The risk of sludge overflow due to high inflows is still present, though reduced to high flows for an extended period, which overflow the large storage tank


§ There is no further upgrade potential of the SBR § Some works need to occur on an operating plant



90-12-53 Date issued: 23/05/2014 of 94 Rev: B





Option 3 – Upgrade SBR and Wet Weather Bypass Option 3 involves installing a wet weather bypass from the inlet works to the CCTs and upgrading the

existing SBR capacity. Dry weather peak instantaneous flows will be accommodated by a small balance tank

adjacent to the inlet works. Wet weather peak flows will be bypassed around the main treatment process to

protect the SBR by maintaining below 30 L/s. In order to maintain a Class C effluent in the lagoon as best as

practical, a high chlorine dose will be applied to the bypass flow. The SBR will be ultimately upgraded to a

2,600 EP capacity, therefore meeting the projection load requirements of 2,530 EP, through upgrades to the

tank capacity, weir length and aeration capacity. The inlet works and CCTs will be upgraded as per all

options.



1

· Install 30kL storage tank, pump and overflow to a wet weather bypass

· Install Wet Weather Bypass to CCT inlet · Common hydraulic upgrade – Inlet works and sludge

lagoon overflow valves



2

· Increase aeration capacity · Upgrade of aeration and decanting controls · Upgrade electrical switchboard and building · Reduction of SBR operation cycle to 3 hours (from 4.8hrs) · Common biological upgrade – pH and alum dosing only

2,100EP biological capacity



2016

3

· Increase decanter length from 3 metres to 6 metres and raise by 225mm

· Raise SBR walls by 225mm · Common biological upgrade works – CCT tank and

chlorine dosing only




2018

Option 3 is similar Option 2, including staging, except that a small balance tank and wet weather bypass

would replace the large balance tank.

The small balance tank will smooth the instantaneous peak pumped flows of 54 L/s, returning flows to the

inlet works, and the bypass will cater for wet weather flows, transferring them to the CCT inlet for

chlorination.








1

Inlet works and sludge lagoon valves 30kL storage tank, pump and overflow to WW bypass 30m of 225mm wet weather bypass Minor electrical and SCADA work

$246,000 2014/15

2

Increase aeration capacity Upgrade of aeration and decanting controls Chemical dosing upgrade – pH and alum dosing Electrical switchboard, and building (electrical or blower) upgrade Minor electrical and SCADA work

$1,136,000 2015/16*

3

SBR weirs and walls - New weirs and pits, raise SBR walls 225mm Chemical dosing upgrade – chlorine dosing only Chlorine Contact tank duplication Minor electrical and SCADA work

$1,080,000 2017/18

Total $2,462,000


All works should be designed together to ensure hydraulic issues are consistently resolved. Inlet works


wet season.

Benefits and Risks

The benefits/advantages and risks/disadvantages of this option are listed in Table 7-9:





§ The inlet works can be implemented as soon as the design is finished (original funding in 2013/14)

§ The SBR treatment process is protected against high flow sludge impacts

§ Hydraulic constraints are significant and restrictive for the design of the inlet screen pit and large balance tank

§ The inlet screen pit is submerged near the end of each treatment cycle as the increased TWL of the SBR is above the inlet pit IL

§ Raw wastewater bypass may increase lagoon nutrients and impact the lagoon quality, compromising the end use of effluent, as Class C recycled water.


§ There is no further upgrade potential of the SBR § All works need to occur on an operating plant , there is

no storage or shutdowns available.




Option 4 – Duplicate SBR This option involves installing a new 618 kL SBR unit adjacent to the existing SBR, as originally anticipated

in the initial plant design. The peak flows can be distributed between the two SBR units, maintaining peak

flows below 30 L/s in each SBR and protecting the treatment process. Doubling the SBRs will cater for the

required load of 2,530 EP by increasing the total capacity to 3,000 EP and also meeting the 54 L/s

instantaneous flow capacity. No upgrades will be required in the existing SBR. The inlet works and CCTs will

be upgraded as per all options.

Table 7-10 outlines the works required for Option 4.

Table 7-10: Option 4 - Description of works


1

· Construct SBR tank, install weir and pipework, return pump and pipework

· Common hydraulic upgrade – Inlet works and sludge lagoon overflow valves


>30L/s pumped flow to plant

(required now)

2

· Install aeration equipment, and WAS system · Upgrade electrical switchboard and building · Install common biological upgrade - CCT and dosing

systems




2016

The proposed SBR tank will be installed to run in parallel with the existing SBR, mirroring the current

treatment once stage two is finished, and providing 60L/s and 3,000 EP capacity.

In the interim, to meet the hydraulic capacity requirements, the SBR tank will act as a large balance tank,

with return pump and pipework for peak pumped flows of 54 L/s. Though not included in this option, it may

be advantageous to also install the small balance tank, to accommodate daily pump flow variations. Note

that the return pump or small tank will not be required if Stage 2 is completed with Stage 1.

Capital Cost Estimate The following table shows the staged capital cost estimate for Option 4.



1

Inlet works and sludge lagoon valves Construct SBR tank, install weir and pipework (with return pump and pipework if stage 2 is delayed) Site access road relocation Minor electrical and SCADA work

$1,112,000 2014/15

2

Install aeration equipment, and WAS system Install common biological upgrade - CCT and dosing systems Chemical dosing upgrade – pH and alum dosing Electrical switchboard, and building (electrical or blower) upgrade Minor electrical and SCADA work

$1,473,000 2016/17

Total $2,585,000





All works should be designed together, to ensure hydraulic issues are consistently resolved. Inlet works


wet season.

Project cost efficiencies may outweigh delayed investment, if biological upgrade installation work (Stage 2) is

delivered with the hydraulic upgrade (Stage 1) in a combined construction works package. For Option 4,

some minor infrastructure works will not be required where both stages are completed simultaneously.

Benefits and Risks

The benefits/advantages and risks/disadvantages of this option are listed in the following table:




§ The existing SBR is fully utilised to its original capacity § The inlet works can be implemented as soon as the

design is finished (original funding in 2013/14) § The large storage tank will allow for storage of over 1

day at ADWF, allowing shut down of the SBR for maintenance or capital works.

§ The risk of sludge overflow due to high inflows is very low, as two SBRs double the capacity to 60L/s

§ The risk of compromised treatment quality is low, with two SBRs in parallel being both effective and resilient to treatment spikes, additional loading or environmental changes.

§ Opportunity for improved effluent quality § Duplicate parallel systems provide redundancy and

ease maintenance constraints § The additional capacity provided with a second SBR

delays the next stage of infrastructure – diversion to Cedar Grove WWTP at $9.5 million – by 2 years. Additional WWTP upgrades are also available to further delay this infrastructure.

§ Hydraulic constraints are moderate for the design of the inlet screen pit and large balance tank

§ Raw wastewater will be stored in the SBR until flows reduce enough to be treated, potentially creating an odour issue.

§ Infrastructure is greater than the need for capacity until 2021




Option 5 – Parallel Package Plants This option involves installing parallel package plants adjacent to the existing SBR. The peak flows can be

distributed between the two process trains (i.e. existing the SBR and a new package plant unit), maintaining

peak flows below 30 L/s in the existing SBR to protect the treatment process. The existing SBR and the new

package plants will cater for the required load of 2,530 EP, increasing the total capacity to 2,600 EP and

meeting the 54 L/s instantaneous flow capacity. No upgrades will be required in the existing SBR. The inlet

works and CCTs will be upgraded as per all options.

Table 7-13 outlines the works required for Option 5.



1

· Install 500EP package plant, foundation and pipework · Common hydraulic upgrade – Inlet works and sludge

lagoon overflow valves · Upgrade electrical switchboard and building · Install common biological upgrade - CCT and dosing

systems



>30L/s pumped flow to plant

(required now) 1,500 EP biological

capacity (CED adjusted)

2 · Install 600EP package plant, foundation and pipework 2,600 EP biological capacity



2016

The package plants will be installed to run in parallel with the existing SBR. The first parallel plant will cater

for 500 EP and also high flows of 22 L/s. The second plant will cater for an additional 600 EP, and has the

flexibility of being increased, once future growth is more clearly understood, as are the planning for and

benefits of Cedar Grove infrastructure delays.


The following table shows the staged capital cost estimate for option 5.



1

Inlet works and sludge lagoon valves Install 500EP Parallel Package Plant, foundation and pipework Upgrade electrical switchboard and building Install common biological upgrade - CCT and Cl dosing systems

$1,468,000 2014/15

2 Install 600EP Parallel Package Plant, foundation and pipework Minor electrical and SCADA work $2,078,000 2016/17

Total $3,546,000




All works should be designed together, to ensure hydraulic issues are consistently resolved. Inlet works


wet season.

Benefits and Risks

The benefits/advantages and risks/disadvantages of this option are listed in the following table:



§ Works are staged to accommodate delayed biological load/ catchment growth and provide flexibility for future plant sizing

§ The existing SBR is fully utilised to its original capacity § The inlet works can be implemented as soon as the

design is finished (original funding in 2013/14) § The risk of sludge overflow due to high inflows is very

low, as the first new package plant will provide adequate hydraulic capacity

§ The risk of compromised treatment quality is low, with two plants in parallel likely to be both effective and resilient to treatment spikes, additional loading or environmental changes

§ Parallel systems provide redundancy and ease maintenance constraints

§ The second stage of this infrastructure can be upsized to delay the diversion to Cedar Grove WWTP at $9.5 million, by a number of years, and sized when growth is more visible.

§ Hydraulic constraints are moderate for the design of the inlet screen pit and large balance tank

§ Raw wastewater will be stored in the SBR until flows reduce enough to be treated, potentially creating an odour issue.

§ Infrastructure is greater than the need for capacity until 2021

§ Division of flows will not be 50/50, thus creating flow control requirements at the flow splitter (inlet works)

§ Multiple treatment technologies require operator training, different process understanding and provide additional scope for errors.




8. OPTION EVALUATION A dual cost and non-cost assessment was undertaken to determine the preferred upgrade option for the

Jimboomba WWTP.

Cost Analysis The five options were compared by using an NPV analysis of capital and operational costs, with the results

outlined in Table 8-1. The NPV analysis spans 2014 to 2039 (25 year period), using the standard LWA

discounted rate of 4.75%.

Capital Costs are developed as design estimates for each option, incorporating unit costs from a variety of

sources including our LWA estimator and suppliers. Capital cost estimates include 30% contingency, and

have been staged to accommodate immediate hydraulic constraints and biological constraints (staged where

applicable). Details for the capital costs for each option are contained within Appendix E.

Existing operational costs are based on K. Hartley estimates and adjusted according to actual flows received

at the WWTP. Future additional operational costs were estimated based on new equipment electricity use (at

$0.15/kWh), maintenance costs at 1% p.a. of total capital works, additional chemicals ($5,000/year) and

additional labour at a workload increase of up to 3 days, dependant on upgrade operational complexity (at

$50/hr).

Table 8-1: Capital, Operational and NPV Cost Comparison Across Jimboomba WWTP Upgrade Options

Option 1 – Upgrade SBR and peak flow balancing tank


and wet weather

balancing tank


and wet weather bypass

Option 4 – Duplicate SBR

Option 5 – Parallel

Package Plant

Capital cost (2014 $) $2,416,696 $2,623,708 $2,462,079 $2,585,373 $3,546,399

Operational cost (2014 $)

(2014/15-2039/40)

$5,809,658 $5,832,131 $5,784,127 $5,956,966 $6,029,288

NPV $12,665,380 $12,778,156 $12,575,630 $12,328,301 $13,921,010

Rank 3 4 2 1 5

% Variation from lowest NPV 3.1% 4.2% 2.3% 0.0% 14.8%

Options 1-4 have similar capital costs, with Option 5 - Parallel Package Plants having a significantly higher

capital cost, by around $1m. As expected, Option 1 had the lowest capital cost due to the minimal proposed

infrastructure.




Operational costs vary only slightly across the options, primarily due to the timing of the upgrades. Details for

the operational costs for each option are contained within Appendix C. Option 3 has the lowest associated

operational cost.

Option 4 has a higher final capacity (3,000 EP as opposed to 2,600 EP for all other options), which can

provide a two year delay on the Cedar Grove infrastructure, based on current short term growth predictions.

Given the Jimboomba WWTP capacity is the primary driver for the Cedar Grove Transfer Infrastructure, the

associated $9.5m infrastructure capital costs and operational cost (including proportional treatment costs -

Logan South Waste Water Servicing Strategy, LWA 2014) have been included in the NPV comparison.

8.1.1 Population Sensitivity Analysis The current short-term population projection is for 13% per annum growth over 2015 and 2016, with growth

rates estimated between 5% and 8% p.a. until 2031. This rate is lower than Logan South Region growth rate

predictions (Logan South Waste Water Servicing Strategy, LWA 2014) and excludes the potential of either

advanced development or development out of sequence with current planning in the small Jimboomba

catchment.

A sensitivity assessment was conducted to determine the impact of varied short term growth rates on

infrastructure timing and the outcomes of the overall NPV. The current growth estimate was compared

against bulk growth at 200 EP/yr over 2 years (from 2015 to 2016) on top of the assumed growth rates, and

also varied growth rates of 10%, 5% and 2% (from 2014 until the ultimate expected growth rate was

reached).

The impact on the NPV of varied growth rates is detailed in Table 8-2.

Table 8-2: Population Sensitivity Assessment – NPV Comparison

NPV (25 yr) NPV (31 yr) *

Current +400EP over 2015 &2016

10% growth rate 5% growth rate 2% growth rate

Option 1 $12,665,380 $13,770,203 $13,365,420 $11,890,921 $19,523,200

Option 2 $12,778,156 $13,943,489 $13,449,761 $11,855,958 $19,747,813

Option 3 $12,575,630 $13,759,042 $13,258,440 $11,635,445 $19,402,731

Option 4 $12,328,301 $12,393,161 $13,264,608 $11,446,646 $20,270,423

Option 5 $13,946,892 $15,028,153 $14,624,036 $13,277,371 $21,531,845

* 31 year NPV assumed for 2% growth rate due to delayed capital works

NPV variations are most significant when the timing of capital costs of new works are delayed or advanced

for each option. The delay of infrastructure from the proposed staging of 2014, 2016 and 2017 is shown in .

The population sensitivity analysis shows that:

· Option 4 remains the preferred option due to the delay of the $9.5m capital works to transfer flows to

Cedar Grove WWTP by up to 3 years relative to other options. The cost difference to Option 3 for the

10% growth rate is only minimal.




· For the 2% scenario, the operational costs at the Jimboomba WWTP has a greater impact on the

NPV than the cost of the Cedar Grove transfer infrastructure, which indicates that transferring flows

to Cedar Grove, is more cost effective than running the Jimboomba WWTP indefinitely.

· Both an additional 400 EP and 10% growth rate will bring forward Stage 3 of the Jimboomba WWTP

upgrades and Cedar Grove transfer infrastructure, whereas 5% and 2% growth rate delay both

Stage 3 of the WWTP upgrades and Cedar Grove transfer infrastructure relative to the proposed

upgrade timing.

Multi Criteria Analysis A multi-criteria (non-cost) assessment workshop has held on the 3rd April 2014 to identify non-cost

benefits/constraints/risks and opportunities for the identified strategies. This workshop engaged LCC

stakeholders from the following areas:

· Treatment

· Water Business

· Asset Management

· Water Product Quality

Table 8-3 summarises the categories and associated weightings adopted for this assessment as agreed in

MCA workshop.

Table 8-3: MCA Framework and Weighting

Assessment Criteria

Criteria Weighting Sub Criteria Description Sub Criteria

Weighting

Technical/ Operational/

Risk 30%

Process redundancy, reliability and flexibility

Risk (likelihood and impact) of failure of biological process or hydraulics, including

redundancy. 40%

Operability, maintainability, safety

aspects

The ability to operate, maintain and access infrastructure in a safe and efficient manner. 40%

Constructability & risk

Ease of implementation on working plant Risks associated with construction of

infrastructure, including safety, construction method and unknown factors.

20%

Environmental 40%

License compliance

Risk of License non-compliance; ability to discharge only.

Impact on re-negotiations of new license for controlled wet weather releases to creek

30%

Impact to waterways Lagoon water quality and impact on Hendersons creek when released. 30%

Impact to land Irrigation impacts (to soil, animals etc) from any reduction of effluent water quality in lagoon. 40%

Social 30%

Ability to supply 3rd party reuse water to

customers

Lagoon water quality of Class C guideline (preferably) with no BGA or BGA toxins

present. 60%

Local resident impacts Impacts of noise and odour on local residents including SES office, Public health risk re BGA 40%




The agreed primary categories were social, environment, and technical/operational/risk. Table 8-4

summarises the outcomes of the MCA workshop.

Table 8-4: MCA Outcomes

Assessment Criteria Sub Criteria

Option 1 – Upgrade SBR and peak flow

balancing tank

Option 2 – Upgrade

SBR and wet weather

balancing tank

Option 3 – Upgrade SBR and

wet weather bypass

Option 4 – Duplicate

SBR

Option 5 – Parallel Package

Plant

Technical/ Operation/

Risk

Process redundancy, reliability and flexibility 2 4 3 9 9

Operability, maintainability, safety aspects 2 5 2 9 7

Constructability & risk 2 4 2 9 7

Environmental

License compliance 1 5 2 10 10

Impact to waterways 2 7 1 10 10

Impact to land 3 4 2 7 8

Social

Ability to supply 3rd party reuse water to customers 2 8 1 10 10

Local resident impacts 6 4 7 5 7

MCA Score (out of 10) 2.52 5.32 2.42 8.62 8.66

MCA Rank 4 3 5 2 1

The MCA analysis indicates that based on non-cost criteria, Options 5 and 4 are preferred. The MCA

demonstrated that:

· Options 1 to 3 all upgrade the existing SBR, with the restrictions for hydraulic capacity,

constructability issues, lack of redundancy and wet weather impacts on the SBR and/or effluent to

the storage lagoon

· Options 1 and 3 pass raw wastewater, or near raw wastewater, to the CCT tank, during peak wet

weather flows (over half an hour of pumping). Lagoon water quality is paramount to the end use, as

Class C irrigation water for third party irrigation of a golf course and horse paddocks. Toxic algae

outbreaks, partially due to high nutrients, inhibit the use of this water.

· Options 4 and 5 both provide redundancy, total wet weather management (to 54 L/s), staged

implementation and potential for an improvement of effluent quality




Preferred Option and Staging Based on both the MCA and NPV cost assessment results, the duplicate SBR (Option 4) provides the best

NPV solution and comparative best non-cost benefits. This option represents a reduced risk of operations,

while providing flexibility for growth beyond 2021 (if the transfer to Cedar Grove is deferred) and for varying

growth rates in the short-term.

Due to the anticipated scheduling for design, funding and period between stages (12 months) the SBR

upgrade should ideally be completed in 2015/16 financial year, with the small balance tank and inlet upgrade

works designed and installed early in 2014/15 financial year. The immediate works will bring relief to the

treatment process, by reducing peak instantaneous flows during dry weather days, while the upgrade is

undergoing detailed design.

The revised capital cost and NPV for this preferred option are provided in the following table and compared

to Option 4. The variation from the lowest NPV cost is approximately 1.6%, indicating that constructing Stage

1 and 2 consecutively does not significantly affect the overall cost profile.

Table 8-5: Preferred Option Costs and NPV Compared with Option 4

Costs Option 4 Preferred Option

Capital Cost $2,585,373 $2,603,531*

Operational Cost (2014/15-2039/40) $5,956,966 $6,116,766

NPV $12,328,301 $12,502,235

% Variation from Lowest NPV NA 1.6%

* Does not include $200,000 for inlet works fine screening equipment (already in CWP)

The small balance tank and associated infrastructure were not originally costed in option 4, and have

resulted in a marginal cost increase in the preferred option in comparison to Option 4.

Table 8-6 below shows the preferred option itemised works, and staging (year).




Table 8-6: Preferred Option Itemised Works and Staging


1 Inlet works and sludge lagoon valves Small tank, foundations, pipework and pump $369,000* 2014/15

2

Construct SBR tank, install weir and pipework (with return pump and pipework if stage 2 is delayed) Minor electrical and SCADA work Install aeration equipment, and WAS system Install common biological upgrade - CCT and dosing systems Chemical dosing upgrade – pH and alum dosing Electrical switchboard, and building (electrical or blower) upgrade Minor electrical and SCADA work

$2,435,000 2015/16

Total $2,804,000

*Additional cost of $200,000 for inlet works fine screening equipment (already in CWP) included in above

Stage 1

Figure 8-1 shows the future site master plan, and illustrates the layout of the proposed works.




SITE MASTER PLAN

Figure 8-1: Preferred Option Site Master Plan




8.1.2 Future considerations for the preferred option development A number of issues will need to be managed, considered and addressed throughout the development of the

preferred option:

· Timeliness of delivery of the final SBR, due to current biological limits and hydraulic capacity

· The hydraulic constraints on the existing plant, upstream and downstream of the inlet pit, which

will impact the inlet screen design, inlet pit modifications and small tank TWL (and operation),

pipework configuration, inlet pit overflow weir height, and sludge lagoon valves and their

operational parameters

· SBR design improvements, which should be pursued and may be retrofitted to the existing SBR

if they prove effective

· SBR operations may be sequential batch reactor style during normal flows, changing to

continuous inflow batch reactor during high flows (where cost effective)

· Potential future upgrade of both SBRs to maximise the life of the plant, and thus another

upgrade of the CCT may also occur

· Shallow manhole at the CCT outlet, management of flows and surcharge, at this manhole and

the short section of main upstream (fall rate downstream of this point is 9.75%).

· The 30kL storage tank has potential for creating odour issues due to short term storage of raw

wastewater. The tank may be fitted with automated wash down sprinkler. If odours become

significant, odour management such as a carbon filter should be fitted to the tank vent.

· A new switchboard being installed in May-June 2014 will allow the installation of new blowers.

Space within the 2014 switchboard should be utilised and the blowers could be relocated to the

new proposed building, allowing both switchboards in one building and blowers in the other

· DEHP negotiations for lagoon effluent release to Hendersons Creek may result in lagoon

effluent quality compliance limits, which will need to be considered in terms of the SBR biological

process and CCT treatment.




9. CAPITAL WORKS PROGRAM IMPLICATIONS The following table provides the four capital works items for the 2014/15 and 2015/16 capital works

programs. The preferred staging and capital works to be added to the capital works budget is as follows:

· FY14/15 – inlet works upgrade ($0.20m) and installation of an instantaneous peak flow balance tank

($0.17m)

· FY15/16 – new SBR unit and upgrade CCTs ($2.44m)

This equates to a total of $2.8m for the upgrade of Jimboomba WWTP.

Table 9-1: Capital Works Program Amendments

CWP ID Task Description Status Year Scheduled

Cost ($XXXX)

Amendments

Unassigned 90-12-53

Jimboomba WWTP Stage 1 – Upgrade inlet works and install instantaneous balance tank · delivery and

installation, return pump, pipework, inlet pit diversion weir

· new inlet screen and civils

· upstream flow monitoring

· sludge lagoon valves

Detailed planning 2014/15 $369,000

Add new

item

Unassigned 90-12-53

Jimboomba WWTP Stage 2 – SBR Upgrade: · new SBR · upgrade CCTs · upgrade chemical

dosing · new switch board

/blower room

Detailed planning 2015/16 $2,435,000

Add new

item




10. CONCLUSION The Jimboomba WWTP is currently limited to a 1,500 EP biological load and a 30 L/s hydraulic load,

ensuring that sufficient treatment is maintained in accordance with current limits. This capacity will avoid

settled sludge blanket uplift/scour and the carryover of solids into the CCTs or a complete ‘wash-out’ of

suspended solids. The WWTP is further constrained to 35 L/s at the inlet works (based on the inlet screens

and upstream sludge lagoon connections and manhole levels) and 31 L/s at the CCT to maintain adequate

disinfection.

An internal assessment of the population growth (based on the previous IDM and expected development

within the area), indicates an estimated 2,730 EP by 2021. The equivalent biological load for this population

is approximately 2,530 EP, due to a high number of existing connections serviced by a CED system. The

maximum instantaneous pumped flow to the WWTP could reach 78 L/s by 2021 for the assumed network

pumping configuration, which is far above the corresponding catchment PWWF of 35 L/s for that year. By

commissioning the existing VSDs in the key pump stations, the projected instantaneous peak flows could be

reduced to approximately 54 L/s until 2021.

Several upgrade options were developed based on the assumed maximum pumped inflow of 54 L/s and a

contributing population of 2,600 EP by 2021. At this time, Strategic Planning assumed that the Jimboomba

WWTP will be decommissioned and flows transferred to the proposed Cedar Grove WWTP. Five options

were assessed in detail, included upgrading the existing SBR while mitigating peak flows (in the form of flow

balancing tanks or wet weather bypass) or alternatively duplicating the treatment train.

All three upgraded SBR options (with mitigated peak flows) and the duplicated SBR option had a similar

range of capital costs, from $2.4million to $2.6million. NPV costs over a 25-year period (including the future

transfer main costs to Cedar Grove and associated operational costs) ranged from $12.3million to

$12.8million. The parallel package plant option was approximately $1million higher in both capital and NPV

costs.

The upgraded SBR options (Options 1 to 3) included either a small balance tank or a wet weather bypass for

peak flows scored poorly in the MCA (2.42 to 5.32 out of 10) due to reduced treatment standards during

peak flows, which would impact on recycled water users and the environment and reduced process

redundancy and maintainability. The parallel treatment options 4 and 5 (duplicate SBR and parallel package

plant options) scored the highest in the MCA (8.62 and 8.66 out of 10).

Based on the cost and non-cost considerations, duplicating the SBR to accommodate hydraulic and

biological increases is the preferred option, with a low capital and NPV cost, a high MCA scoring and the

flexibility to stage works with flow balancing during the initial stages. The duplicate SBR option also allows

for some flexibility in the construction of the transfer pipeline to the proposed Cedar Grove WWTP.




11. RECOMMENDATIONS The Logan Water Alliance recommends that Logan City Council (LCC):

1. Adopt the construction of a duplicate SBR as the preferred upgrade strategy for the Jimboomba

WWTP, which incorporates the following works:

a. Stage 1 works (FY14/15) – install new inlet works and fine screen with 30 kL flow balancing

tank

b. Stage 2 works (FY15/16) – commission a duplicate SBR and chlorine contact tanks

2. Proceed immediately to with the detailed design of the inlet works and 30 kL balance tank

3. Implement pump station management of the upstream LCC operated pump stations, which involves:

a. Stage A (pre-WWTP commissioning) – delaying SPS73 connection to 150 mm rising main,

VSD control and duty/standby operation of SPS74, and installing systemic control between

SPS73 and SPS74

b. Stage B (post WWTP upgrade) – VSD control, duty/standby operation and limiting flows to

minimum velocity requirements for SPS73 and SPS74

4. Continue to monitor effluent performance and impacts of the WWTP changes on the effluent storage

lagoon.




12. REFERENCES Hartley, 2009, Jimboomba WWTP EVOP Review

Hartley, 2009, Jimboomba: Detailed Planning for 2015/16 Wastewater Treatment and Effluent Management Scheme - Planning Report for WWTP Upgrade

Hartley, 2010, Jimboomba WWTP - Assessment of Capacity Potential

LWA, 2011, Jimboomba WWTP Upgrade Project Development (Task Number 90-10-87-001). Prepared in November 2011.

LWA, 2013, Jimboomba Recycled Water Management Plan (Task Number 90-11-46). Prepared in July 2013.

LWA, 2013b, Jimboomba WWTP Wet Weather Effluent Management Strategy (Task Number 90-12-42). Prepared in December 2013.

LWA, 2014, Revision of Logan South Wastewater Network Servicing Strategy (Task Number 90-12-21). Prepared in January 2014.



90-12-53 Date issued: 23/05/2014 Rev: 1

Appendix A Desired Standards of Service



90-12-53 Date issued: 23/05/2014 Rev: 1

WASTEWATER NETWORK DSS

Parameter Criteria

Sewage load

ADWF 200L/EP/day

PDWF 2 x ADWF

PWWF

Residential 1300 L/EP/d For CED PWWF = 660 L/EP/d Commercial 1300 L/EP/d

Light Industrial 1000 L/EP/d

Heavy Industrial 840 L/EP/d

Gravity sewer design

Flow equation Manning's 'n' or Colebrook White can be used. For modelling Colebrook–White is preferred

Pipe roughness general Manning's 'n' =0.013 or Colebrook White k = 1.5 mm

Minimum velocity @ PDWF 0.35 m/s

Maximum velocity @ PWWF 3 m/s Depth of flow @ PWWF — existing Up to 1 m below MH surface level and no spillage through overflow structures

Depth of flow @ PWWF — proposed 75% of pipe depth

Minimum grades

Diameter Grades (mm, 1 in X)

150 150 (80 in last section between last manholes or to an end)

225 290

300 400

375 500

450 600

525 700

600 850

675 925

750 1000

825 1000

900 1090

1050 1270

1200 1450

Sewerage pump stations

Wet well operating requirements

V (m3) = 0.9 x pump rate (L/s) N Where N is the acceptable number of starts per hour Pump Rate (L/s) = capacity of the largest duty pump N = 12 for motors <= 15 kW N = 8 for motors 15kW - 200 kW N = 5 for motors > 200 kW Control levels are based on Table 5.1 of WSA04-2005. The minimum depth between duty start and duty off is 100 mm and ideally should be 300 mm or greater.



90-12-53 Date issued: 23/05/2014 Rev: 1

WASTEWATER NETWORK DSS

Parameter Criteria

Emergency storage

Four hours of ADWF (local gravity catchment only) Except where otherwise specified to meet the requirements of the overflow risk assessment If there is an overflow pipe, storage in the system is measured between the alarm level and overflow pipe invert level. If there is no overflow pipe, storage is measured between the alarm level and 300 mm below the lowest upstream manhole or top of wet well.

Pump capacity

If PWWF <20L/s, then two pumps (duty/standby arrangement) will be provided, with each pump being capable of delivering PWWF. If PWWF >20L/s and <200L/s, then two pumps (duty/duty assist arrangement) will be provided, with each pump being sized so that the two pumps running in parallel are capable of delivering PWWF. It is desirable that a single pump be sized on C1 if appropriate. i.e. From QDNRM. C1 = 15 x EP-0.1587 minimum 3.5, maximum 6.5. If PWWF >200L/s, then minimum of three pumps (duty/duty assist/standby arrangement) will be provided. Duty/duty assist pumps being capable of delivering PWWF with each pump being sized in consultation with Allconnex Water.

Pump operation VSD will only be used subject to special approval from Allconnex Water. If approved by Allconnex Water, the VSD operating regime will be selected to ensure sufficient self-cleansing velocities, and will meet the pump supplier’s requirements.

NPSH Refer Clause 6.4 of WSA04-2005

Rising mains

Flow equation Hazen Williams or Colebrook–White. For modelling, Colebrook–White is preferred

Friction mains

100–300 mm diameter, C =110 > 300 mm diameter, C =130 Colebrook–White to follow method in WSA04. The pump curve will include the minimum static head with C=140 to confirm that the pump operates over the full range (i.e. to the overflow level) in the wet well.

Minimum velocity Minimum velocity will be not less than 0.9 m/s, but preferred minimum is 1.5 m/s. Refer Clause 10.3.5 of WSA04-2005.

Maximum velocity 2.5 m/s proposed systems

Max detention time

Maximum time of detention in pressure main and SPS wet well is six hours (two hours in wet well and four hours in rising main) based on daily average flows to minimise potential for odour or hydrogen sulfide generation. Where high retention times are likely to occur, odour and sulfide control measures will be required to the satisfaction of Allconnex Water. (Refer WSA 07-2007-1.1 section 3.15)

Reduced infiltration gravity sewers (RIGS)

As per gravity sewers except Not permitted without Allconnex Water approval

PWWF 1000L/EP/d

Single pump capacity Standard: C1 x ADWF

C1 = 9.322 x EP-0.1249 minimum 3.0, maximum 4.

Total PS capacity 1000L/EP/d

Low pressure sewers / vacuum pumps Low pressure sewers / vacuum pumps Are not preferred and will only be allowed subject to approval from Allconnex Water.

Private pump stations and rising mains

Private pump stations and rising mains are permitted for single users only and no connection or sharing will be permitted without approval from Allconnex Water

Common effluent discharge

Common effluent discharge (CED)

Not permitted without approval from Allconnex Water.



90-12-53 Date issued: 23/05/2014 Rev: 1

Appendix B Jimboomba Wastewater Catchment Pump Station Management Analysis



90-12-53 Date issued: 23/05/2014 Rev: 1

The Jimboomba wastewater treatment plant (WWTP) experiences excessive flows at times due to the

operation of pump stations assets in the wastewater network. The implications of excessive flow on the

WWTP include:

· Washout of the treatment plant process (impacting treatment for up to two weeks and contaminating

the downstream effluent lagoon)

· Surcharging of the inlet works and upstream infrastructure

These issues were observed in March 2014, when a large wet weather event triggered two Council pump

stations (i.e. SPS73 and SPS74) to pump continuously for 3 and 5 hours respectively, which surcharged the

inlet works, flooded the sludge lagoon, and washed out the treatment plant.

There are opportunities in the current and future operational configuration of the upstream network to

minimise pumped flows to the WWTP. The analysis performed on network assets as part of this study aims

to address the current hydraulic issues and to determine the future flows between the network and the

Jimboomba WWTP. This will assist in the development of appropriate treatment capacity options.

Jimboomba Wastewater Catchment

The existing wastewater network consists of traditional gravity sewers, common effluent drainage (CED)

systems, five Council owned sewerage pump stations (SPS), two existing and one future private pump

stations (PPS).

Figure -B1 and Figure -B2 provide an overview of the Jimboomba wastewater catchment and its

infrastructure.



90-12-53 Date issued: 23/05/2014 Rev: 1

Figure -B1: Jimboomba Wastewater Catchment

Figure -B2: Jimboomba Wastewater Configuration (Up to 2021) - Schematic

Jimboomba WWTP

SPS73 Pump Station

Hills College PPS Pump Station

SPS80 Pump Station

SPS73 Gravity Catchment

SPS77 Pump Station

SPS76 Pump Station

SPS75 Pump Station

SPS74 Gravity Catchment

SPS74 Pump Station

Child Care PPS Pump Station

DN80 RM (Future commissioning of DN150 RM)

DN150 RM (DN80 RM – Not in existing use)

DN100 RM

DN50 RM DN50 RM

DN50 RM

Private PS RM

Private PS RM

Gravity Network Gravity Network

Gravity feed to inlet works

Stockland PPS Future Pump Station

Future DN80 RM (former SPS74 RM)



90-12-53 Date issued: 23/05/2014 Rev: 1

The WWTP receives flows directly from SPS73, SPS741, Hills College PPS and the Johanna St Child Care

Centre PPS. An additional private pump station is planned for the catchment, which will be associated with a

future Stockland development (i.e. Stockland PPS).

The rising main arrangement associated with SPS73 and SPS74 is as follows:

· Pump station SPS73 transfers flows to the WWTP via a DN80 rising main. A new DN150 rising

main augmentation has been constructed, but is yet to be commissioned.

· Pump station SPS74 has recently been connected to an augmented DN150 rising main to increase

the capacity of the pump station due to its history of wet weather overflows.

Servicing Strategy

The East Street Jimboomba Wastewater Conveyance – Detailed Planning and Preliminary Design (LWA,

Jan 2014) Planning Report outlines the current adopted servicing strategy for Jimboomba. The high level

servicing strategy for the Jimboomba catchment is based on the transfer of flows to the planned regional

Cedar Grove WWTP in 2021. At this time the transfer infrastructure, consisting of a new pump station and

7.5 km of DN375 rising main, will be constructed to convey flows from Jimboomba to Cedar Grove allowing

the decommissioning of the Jimboomba WWTP. During the expected life of Jimboomba WWTP (i.e. up to

2021) the following catchment changes are anticipated:

1. Growth in the south east (i.e. near East Street) will require a new SPS76 to transfer flows to SPS74

until 2021, and a new SPS80 pumping flows to SPS73

2. SPS73 will be connected to its new DN150 rising main to increase capacity

3. Stockland development along the west of the Mount Lindsay Highway is likely to be completed in the

next few years. It is proposed to connect the Stockland private pump station to the disused SPS74

DN80 rising main

Population and Loadings - Jimboomba Catchment

Table 12-1 shows the Jimboomba network loading by terminal pump station from the 2014 to 2021 planning

horizons, which correlates with the expected remaining life of the Jimboomba WWTP.

Table 12-1: Jimboomba Network Loadings – 2014 to 2021 Planning Horizons Pump Station Loading Planning Horizon

2014 2016 2021

SPS73 / JMSP 1

EP 504 573 743 ADWF [kL/s] 101 115 149 PWWF [L/s] 7.6 8.4 10.9

SPS74 / JMSP 2

EP 1,012 1,283 1,684 ADWF [kL/s] 202 257 337 PWWF [L/s] 9.9 13.8 19.6

Hills College PPS EP 134 134 134 ADWF [kL/s] 27 27 27 PWWF [L/s] 2.0 2.0 2.0

1 SPS74 receives all the common effluent drainage (CED) systems as well as some gravity and upstream pumped flows.



90-12-53 Date issued: 23/05/2014 Rev: 1

Pump Station Loading Planning Horizon 2014 2016 2021

Johanna St Child Care Centre PPS

EP 28 34 34 ADWF [kL/s] 5 7 7 PWWF [L/s] 0.2 0.3 0.3

Stockland PPS EP 0 120 140 ADWF [kL/s] 0 24 28 PWWF [L/s] 0.0 1.8 2.1

Jimboomba Catchment

EP 1,678 2,144 2,735 ADWF [kL/s] 335 430 548 PWWF [L/s] 19.7 26.3 34.9

Existing Capacity – Pump Stations and Jimboomba WWTP

To aid the development of WWTP capacity options out to 2021 it is important to understand the current

capacity of critical assets over this period. This includes terminal pump station assets and the Jimboomba

WWTP.

Based on the status of the existing Jimboomba WWTP and the potential upgrade of the plant to

accommodate future growth and network constraints out to 2021, network capacity needs to be considered

in two stages. These stages include:

· Stage A Existing – Consideration needs to be given to the capacity constraints of the existing plant

to ensure its effective operation up to the resolution of the WWTP capacity constraints

· Stage B Future – Based on current network assets and catchment growth, a suitable capacity

constraint needs to be established for consideration in the development of Jimboomba WWTP

capacity options

Jimboomba WWTP Capacity Constraints

The Jimboomba WWTP has an estimated hydraulic capacity of 30 L/s. Any flows above this are anticipated

to cause solids carryover out of the bioreactor and affect the biological process through eventual process

washout. The existing inlet works has an estimated hydraulic capacity of 35 L/s.

On this basis, Stage A will need to consider a limit of 30L/s or less up until the resolution of any Jimboomba

WWTP capacity constraint resolution.

Pump Station Capacity

Five pump stations will contribute flows directly to the Jimboomba WWTP (refer Figure -B2) between now

and 2021 (refer Table 12-1). These include:

· Two Council owned pump stations (i.e. SPS73 and SPS74)

· Three privately owned pump stations, which include two existing pump station assets (i.e. Hills

College and the Johanna St child care facility) and the future pump station to service the Stockland

development.



90-12-53 Date issued: 23/05/2014 Rev: 1

For the purpose of the Stage A and B assessments it will be assumed that all five pump stations will contribute flows to the WWTP.

Stage A - Existing Assessment

The current capacity of the key pump stations is shown in Table 12-2. The following can be deduced:

· The current capacity of SPS73 (i.e. PWWF 7.0 L/s) is below the expected DSS requirement in 2016

(i.e. PWWF 8.4 L/s). However, a review of actual SCADA suggests that flows into the pump station

are currently less than current projected flows.

· The current capacity of pump station SPS74 is well in excess of DSS requirements in 2016 (i.e.

25.7 L/s / 29.7 L/s actual PWWF capacity versus a 2016 PWWF of 13.8 L/s). In addition, the

ultimate PWWF estimated for SPS74 is 14.6 L/s.

· The overall Jimboomba catchment PWWF in 2016 is expected to be 26.3 L/s, which is less than the

current 30 L/s restriction at the Jimboomba WWTP

· Drawdown test results used for this study show a close correlation with theoretical calculations for

SPS73, but a significant error is applicable in relation to SPS74 (refer Table 12-2 and Figure B-12-4).

Further investigation is required to confirm asset characteristics for SPS74.



90-12-53 Date issued: 23/05/2014 Rev: 1

Table 12-2: Pump Station Capacity – Existing and 2016 PWWF

Pump Station RM Nominal Diameter

Single Pump (Duty) Flow

Dual Pump (Duty / Assist) Flow

2016 PWWF

Ultimate PWWF

[-] [mm] [L/s] [L/s] [L/s] [L/s] SPS73 80 6.7 1 7.0 1 8.4 27.3 SPS74 150 25.7 1 29.7 1 13.8 14.6 Hills College 100 8.3 3 - 3 2.0 2.0 Johanna St Child Care 50 2 2.4 4 4.0 5 0.3 0.3 Stockland 80 4.5 6 6 6 1.8 2.6

Total 47.6 55 26.3 46.8 Notes: 1 – Capacity was based on pump station drawdown test with SPS73 connected to a DN80 rising main and SPS74 connected to the existing DN150 rising main 2 – A DN50 rising main has been assumed. This will need to be confirmed in the field. 3 – Flow rate based on ‘as constructed’ drawings and system resistance curves provided. No information provided as to pump configurations and a single pump configuration is assumed. 4 – Minimum flow based on a minimum 0.9 m/s velocity requirement and DN50 rising mains. The DN50 pipe would have a 45mm internal diameter for an assumed PE pipeline. 5 - Maximum flow based on a maximum 2.5 m/s velocity requirement and assuming DN50 rising mains. The DN50 pipe would have a 45 mm internal diameter for an assumed PE pipeline. 6 - Minimum flow based on a minimum 0.9 m/s velocity requirement and DN80 rising mains. A maximum flow rate based on a maximum 2.5 m/s velocity requirement in a DN80 rising main is likely to concur high head loss and unlikely to meet this requirement. Therefore, the flow is unlikely to exceed 6 L/s.

Based on the above the following should be implemented in the short term:

· Pump Station SPS73 – Delay the commissioning of the DN150 rising main and monitor the

performance of the pump station.

If actual ADWF flows for SPS73 exceeds the 2014 ADWF of 1.17 L/s (i.e. 101 kL/day), then

consideration will need to be given to the commissioning of the DN150 rising main. However, this

would require variable speed drive (VSD) control to limit flows to achieve the minimum velocity of

0.9 m/s, a duty / standby mode of operation and systemic control with SPS74 to ensure these pump

stations do not operate in unison.

· Pump station SPS74 – The following measure are required:

o Ensure the pump station operates in a duty / standby mode

o Limit the flows from SPS74 through the use of a VSD to 16 L/s (i.e. minimum velocity of

0.9 m/s)

· Private pump stations – Investigate the ability to limit flows from these sites to achieve minimum

velocity requirements (i.e. 0.9 m/s).

· Systemic control – Program logic into the control of SPS73 and SPS74 to ensure that only one pump

station can function at one time.

These measures should result in a maximum flow being received by the WWTP to be in the order of 29.8 L/s

(refer Table 12-3).



90-12-53 Date issued: 23/05/2014 Rev: 1

Table 12-3: Stage A Network Operation – Prior to Jimboomba WWTP Capacity Augmentation

Pump Station RM Nominal Diameter Flow Operational Measures

[-] [mm] [L/s] [-]

SPS73 80 7.0

· Systemic control with SPS74 · Delay the DN150 rising main commissioning · Monitor ADWF and consider risk of operation

with respect to DN150 rising main commissioning

SPS74 150 17.3 · VSD control to limit flow to 16 L/s to 17.3 L/s

(refer Figure B-12-4) · Systemic control with SPS73

Hills College 100 8.3

· Confirm PPS operation, flow and asset characteristic (i.e. pump curves, operational mode, rising main diameter / material / alignment)

· Based on ‘as constructed’ drawings

Johanna St Child Care 50 4.0


· Limit flow to minimum velocity requirements i.e. 0.9 m/s

Stockland 80 4.5 1



Maximum flow rate 34.1 2

(29.6 without Stockland)

· Flow rate to remain below 30 L/s · Operation to continue until Jimboomba

WWTP upgrade works are commissioned 1 – The flow from the Stockland pump station has been included as there is a possibility that the SPS73 DN80 rising main may become available during Stage A network operations 2 – The maximum flow rate has excluded the SPS73 flow due to the proposed systemic control measures

Therefore, if systemic and VSD control is implemented, the maximum flow rate reaching Jimboomba WWTP

is estimated as 34.1 L/s. This is likely to cause some process issues at the WWTP if sustained for long

pumping periods.

To avoid process issues at the WWTP, the flow may be reduced further to 29.6 L/s if Stockland connection is

delayed until after any WWTP upgrades.



90-12-53 Date issued: 23/05/2014 Rev: 1

Figure B-12-3: Stage A SPS73 – Duty / Assist Single Pump Operation (RM DN80, n = 100%)

Figure B-12-4: Stage A SPS74 – Duty / Standby Single Pump Operation (RM DN150, n = 88%)

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

45.0

50.0

0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 12.0 13.0 14.0 15.0 16.0 17.0 18.0 19.0 20.0

HEAD

(m)

FLOW (L/s)

Jimboomba - Stage B Pump Station SPS73 (DN80 Rising Main)

Single Pump n=100% (FLYGT NP3127.181) Dual Pump (Parallel) n=100% (FLYGT NP3127.181)SYSTEM CURVE (MAX/MIN OPERATION) PWWF - 2014 (7.6L/s) & 2016 (8.4L/s)Minimum / Maximum Flow Velocity Duty Point - Single PumpDuty Point - Dual Pump (Parallel)

Minim

um Velocity

0.9m/s Flow

-4.5L/s

Maxim

um Velocity 2.5

m/s Flow

-12.6 L/s

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

45.0

0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 45.0 50.0 55.0

HEAD

(m)

FLOW (L/s)

Jimboomba - Stage A Pump Station SPS74 (DN150 Rising Main)

Single Pump n=100% (FLYGT NP3127.181) Dual Pump (Parallel) n=100% (FLYGT NP3127.181)SYSTEM CURVE (MAX/MIN OPERATION) Min / Max Flow - Velocity Min 0.9 m/s Max 2.5 m/sDuty Pump (Min) Duty Pump (Max)VSD Control - Single Pump n=88% (FLYGT NP3127.181) VSD Control - Dual Pump (Parallel) n=88% (FLYGT NP3127.181)SPS74 DSS 2016 PWWF

Minim

um Velocity

0.9m/s Flow

-15.9L/s

Maxim

um Velocity 2.5

m/s Flow

-44.2 L/s



90-12-53 Date issued: 23/05/2014 Rev: 1

Stage B – Future Assessment

The Jimboomba WWTP useful life based on the regional strategy for Logan South is currently considered to

be out to 2021. The WWTP has licence restrictions, which restricts releases to the environment. On this

basis the WWTP must be able to pass through DSS PWWF as a minimum.

The following aspects need to be considered in the determination of a suitable design flow rate for any

proposed Jimboomba WWTP capacity augmentation:

· PWWF – DSS 2021 PWWF 34.9 L/s (refer Table 12-2)

· Network Characteristics – Based on current knowledge on existing network assets and envisaged

flows through private pump stations a flow requirement of 53.7 L/s would be required (refer Table

B-4)

Table B-4: Stage B Network Operation – Post Jimboomba WWTP Capacity Augmentation

Pump Station RM Nominal Diameter 2021 Flow Operational Measures

[-] [mm] [L/s] [-]

SPS73 150 17.3

· Commissioning of the DN150 rising main · VSD control to limit flow 16 to 17.3 L/s (refer

Figure B-12-5) · Duty / standby operation

SPS74 150 19.6

· VSD control to limit flow to 18 to 19.6 L/s (refer Figure B-12-6)

· DSS 2021 PWWF 19.6 L/s · Duty / standby operation

Hills College 100 8.3


Johanna St Child Care 50 4.0


Stockland 80 4.5



Maximum flow rate 53.7 · Operation to commence once Jimboomba WWTP upgrade works are commissioned

Therefore, the upgrade options for the Jimboomba WWTP should consider 53.7 L/s as an appropriate

capacity. However, this assumes some form of restrictions can be achieved in terms of flows received from

private pump stations, with the Stockland pump station as a prime candidate.



90-12-53 Date issued: 23/05/2014 Rev: 1

Figure B-12-5: Stage B SPS73 – 2021 Duty / Standby Single Pump Operation (RM DN150, n = 90%)

Figure B-12-6: Stage B SPS74 – 2021 Duty / Standby Single Pump Operation (RM DN150, n = 95%)

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

45.0

0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 45.0 50.0 55.0

HEAD

(m)

FLOW (L/s)



Minim

um Velocity

0.9m/s Flow

-15.9L/s

Maxim

um Velocity 2.5

m/s Flow

-44.2 L/s

0.0

5.0

10.0

15.0

20.0

25.0

30.0

35.0

40.0

45.0

0.0 5.0 10.0 15.0 20.0 25.0 30.0 35.0 40.0 45.0 50.0 55.0

HEA

D (m

)

FLOW (L/s)



Minim

um Velocity

0.9m/s Flow

-15.9L/s

Maxim

um Velocity 2.5

m/s Flow

-44.2 L/s



90-12-53 Date issued: 23/05/2014 Rev: 1

Summary of Recommendations

The Logan Water Alliance recommends that Logan City Council (LCC) should:

1. Confirm asset characteristics for terminal pump stations in the Jimboomba Catchment with priority

given to SPS74. This would include the following:

a. Undertaking pump station drawdown tests to confirm the results noted in this report

b. Confirm the pump characteristics i.e. model, type and pump curve

c. Develop an appropriate system curve for comparison to pump curves and compare theoretical

to test duty flow characteristics

d. Undertake further investigation if discrepancies exist to confirm system operations at the

commencement of detailed design works for the Jimboomba WWTP

2. Modify network operations in the Jimboomba Catchment to ensure that maximum flows do not

exceed 30-35 L/s to the Jimboomba WWTP (refer Table 12-3) in the lead up to the commissioning of

any Jimboomba WWTP capacity augmentation. This will involve the implementation of the following

Stage A operational measures:

a. Delay to the commissioning of the DN150 rising main to pump station SPS73

b. Implementation of systemic control between pump stations SPS73 and SPS74 to ensure that

only one pump station can operate at the one time

c. Implement VSD control at SPS74 to limit flows to minimum velocity requirements (i.e. V = 0.9

m/s)

d. Duty / standby operation for SPS74

3. Seek to limit flows from private pump stations to minimum requirements to provide opportunities for

operational flexibility and or reduction in WWTP upgrade requirements

4. Adopt a maximum flow criteria of 53.7 L/s in the development of Jimboomba WWTP capacity

augmentation options

5. Adjust network operations post the commissioning of the Jimboomba WWTP augmentation works to

include the following (i.e. Stage B operations):

a. Commissioning of the DN150 rising main associated with pump station SPS73, when required

b. Facilitate variable speed drive control at SPS73 and SPS74 to achieve the following:

· Pump station SPS73 - Limit flows to between 16 to 17.3 L/s (i.e. restrict flow to minimum

velocity criteria of 0.9 m/s, which correlates to 16L/s)

· Pump station SPS74 - Limit flows to between 18 to 19.6 L/s (i.e. 2021 PWWF of 19.6 L/s to be

achieved)

c. Duty / standby operation at pump stations SPS73 and SPS74



90-12-53 Date issued: 23/05/2014 Rev: 1

Appendix C Jimboomba WWTP Performance Assessment and Existing SBR Upgrade Reports (Hartley, 2014)

1 16118:Ken Hartley 2-Dec-13

Jimboomba WWTP Performance Review Jul-11 to Sep-13 1. Background The design capacity of the Jimboomba Wastewater Treatment Plant is 1500 EP. It is planned to retain the plant until a new regional facility is constructed at Cedar Grove, possibly around 2021. Three previous reports have assessed the capacity and potential upgrade strategies of the Jimboomba plant; Jimboomba operating data have also been published in a technical paper and a reference text: ¨ Hartley Ken (Sep-08), Jimboomba WWTP: Assessment of Capacity Potential, Logan Water. ¨ Hartley Ken (Jun-09), Jimboomba: Detailed Planning for 2015/16 Wastewater Treatment and

Effluent Management Scheme – Planning Report for WWTP Upgrade, Logan Water. ¨ Hartley Ken (Nov-09), Jimboomba WWTP: EVOP Review to 30-Sep-09, Logan Water. ¨ Hartley KJ & Lant PA (2010), Sludge Settleability in BNR Processes, Water, Jnl Australian

Water Ass, 37, 3, 77-83. ¨ Hartley Ken (2013), Tuning Biological Nutrient Removal Plants, pp 78, 81, 129, IWA

Publishing, London. This memo reviews the plant operating data for the most recent period, Jul-11 to Sep-13. 2. Plant Description Figure 1 shows the plant flowsheet and Table 1 the process details. 3. Loading Plant loading parameters for the twenty seven months Jul-11 to Sep-13 are listed in Table 2 and trended in Plots A1-A3 appended. Median flow and BOD loading for the period were 213 kL/d and 47 kg/d respectively. Assuming a 120 gCOD/EP, a BOD:COD ratio of 2.4 and a 25% reduction in BOD loading via the CEDs in the system, the estimated connected population is 1100-1200 equivalent. Peak daily flow was 4.3 times the median.

Figure 1 Plant flowsheet

SBR F ContactTank

LagoonsSludge

B

B

P WAS

Screen

Sewage Supernatant

P-37

EffluentLagoon

PGolf course

irrigation

Chlorine

DryingBed

PP

Underdrainage


Table 1 Existing Plant – Process Details Item Details Process Units SBR Volume at TWL Volume at LWL Max decant volume Max water depth Chlorine contact tank Volume Effluent lagoon Volume Sludge lagoons Volume Drying bed Area Equipment Capacities Aeration system Blowers Diffusers SOTR WAS pump Decanting weir

Side walls: upper 1.2m vertical, lower sloping 618 kL 526 kL (0.45m maximum decanter travel) 115 kL (with continuous inflow, decanting 20% of cycle time) 4.0m 17 kL 15 ML approx 2 No. ea 280 kL 75 m2 2 No. ea 140 L/s high speed, 50 L/s low speed Rehau fine pore membrane diffusers 35 kg/h per blower, HS (calculated) 1 No. 3 L/s 3m long, max decant depth 0.45m

Table 2 Plant Loading for 27 Months, Jul-11 to Sep-13 Parameter Load

Total Period

Median 90 Percentile Maximum

MASS LOAD Rainfall Raindays / total days Flow kL/d BOD load kg/d

2492 mm 205 / 823

--- ---

--- --- 213 47

--- --- 264 68

160 mm/d

--- 907 177

SEWAGE QUALITY BOD mg/L TN mg/L TP mg/L

--- --- ---

260 66 10

336 81 14

680 130 24

Table 3 Plant Performance for 27 Months, Jul-11 to Sep-13 Parameter Effluent Licence Standards Effluent Quality

Min 50%ile 80%ile Max Min 50%ile 80%ile Max BOD mg/L SS mg/L NH3-N mg/L TN mg/L TP mg/L pH units DO mg/L TDS mg/L E.coli cfu/100mL Free chlorine mg/L

--- --- --- --- --- 6.5 2 --- --- ---

--- --- --- --- --- --- ---

1000 --- ---

10 15 --- --- --- --- --- --- --- ---

20 30 --- --- --- 8.5 --- ---

10001

---

1 1

0.1 2.7 0.1 7.0 0.4 33 <1 0

4 6

0.6 8.8 7.1 7.5 2.1 508 <1 0.4

6 9

3.4 12 8.4 7.7 4.1 626 6

1.0

50 70 22 66 18 8.0 6.7

1150 561

2.1 195%ile – nominal concentration limit from Qld Public Health Regulation 2005.


4. Performance Effluent quality for the twenty seven months Jul-11 to Sep-13 is summarised in Table 3 and trended in Plots B1-B3 appended. Significant features are: ¨ BOD and SS were low except for high flow periods where significant solids carryover

occurred during decanting. ¨ Nitrogen removal was good with median NH3-N and TN levels of 0.6 and 8.8 mg/L. ¨ Effluent median TP was 7.1 mg/L, indicating that no enhanced biological P removal

occurs. ¨ Chlorination was effective, producing low E.coli levels. 5. Operation Process operating parameters for the data period are summarised in Table 4. Figure 2 shows the current 4.8 hour operating cycle. The recorded daily wasting volumes vary and it is uncertain whether the cycle has been consistent over the full data period. The 60 day moving median SRT for the period is 57 days (based on both wasting and effluent SS loss). However as shown in Trend Plot C1 the value varied from 38-96 days, suggesting that the operating cycle may have been varied over the data period. The median MLSS concentration was 3.3 g/L (range 2.1-4.7 as shown in Plot C1). Table 4 Plant Operating Parameters for 27 Months, Jul-11 to Sep-13 Parameter Median Value (and Range) SRT (60d moving average) d MLSS g/L DSVI (since 27-Nov-11) mL/g Effluent NH3-N:NO3-N ratio Cycles: Cycles per day Cycle time min Unaerated fraction: Primary anoxic Secondary anoxic Total

57 (38-96) Plot C1 3.3 (2.1-4.7) Plot C1 101 (42-209) Plot C2 0.12 (0.012-220) Plot C2 Figure 2 5 288 0.21 Less DO decay periods 0.28 Less DO decay period 0.49 Less DO decay periods

Figure 2 Current 288 minute operating cycle (5 cycles per day).

Waste Sludge

Decant

Settle

Aerate

Feed

0 1 2 3 4 5Hours


The sludge settleability (using the DSVI test since 27-Nov-11) has a median value of 101 mL/g (equivalent to an unstirred SVI of about 160 mL/g.1 Trend Plot C2 shows that there is a strong correlation between the DSVI and the effluent ammonia:nitrate ratio.2 The effluent ammonia:nitrate ratio is apparently driven by variation in the plant load (Plot A2 and A3, which include the 60 day moving averages for the BOD mass load and the influent TN concentration) and associated effects on the operating DO concentration and nitrification efficiency. More sophisticated aeration control could allow a lower DSVI level to be maintained more consistently.

1 Hartley Ken (2013), Tuning Biological Nutrient Removal Plants, IWA Publishing.

TREND PLOTS

A 16118:Ken Hartley 2-Dec-13

0

200

400

600

800

0

50

100

150

200

01-Jul-11 01-Jan-12 01-Jul-12 01-Jan-13 01-Jul-13 01-Jan-14

BOD

Con

c (m

g/L)

BOD

Mas

s (k

g/d)

A2. Organic Load BOD mass BOD conc 60 per. Mov. Avg. (BOD mass)

0

5

10

15

20

25

0

30

60

90

120

150


Tota

l P (m

g/L)

Tota

l N (m

g/L)

A3. Nutrients TN TP 60 per. Mov. Avg. (TN)

BOD 80% limit

BOD max limit

SS 80% limit

SS max limit

0

10

20

30

0

25

50

75


SS (m

g/L)

BOD

(mg/

L)

B. EFFLUENT QUALITYB1. BOD & SS BOD SS

0

5

10

15

0

10

20

30


TP (m

g/L)

TN (m

g/L)

B2. TN & TP TN NH3-N TP

0

20

40

60

80

100

120

0

120

240

360

480

600

720


Rain

fall

(mm

/d)

Flow

(kL

/d)

A. PLANT LOADINGA1. Flow Rainfall Flow

TREND PLOTS

B 16118:Ken Hartley 2-Dec-13

Class A 50% & max limits

Class C 50% & max limits

Free Cl2 max limit0

2

4

6

8

10

0.1

1

10

100

1000

10000


Free

Cl2

Res

idua

l (m

g/L)

F. c

ols

(cfu

/100

mL)

B3. Faecal Coliforms & Chlorine F.cols-contact tank Free Cl2 Residual

0

1

2

3

4

5

6

0

20

40

60

80

100

120


MLS

S (g

/L)

SRT

(60d

MA

, d)

WA

S (k

L/d)

C. OPERATING PARAMETERSC1. SRT & MLSS SRT WAS MLSS

DS

VI s

tart

0.001

0.01

0.1

1

10

100

1000

0

60

120

180

240

300

360


Efflu

ent

NH3 -

N:NO

3-N

Ratio

SVI /

DSV

I (m

L/g)

C2. DSVI DSVI NH3:NO3 ratio

0

20

40

60

80

100


N C

onc

(mg/

L)

C3. Effluent N Sewage TN Effluent TN NH3-N

6.0

6.4

6.8

7.2

7.6

8.0


pH

C4. pH - Sewage & ML pH - sewage - ML

TREND PLOTS

C 16118:Ken Hartley 2-Dec-13

0

50

100

150

200

0

0.5

1

1.5

2


Con

tact

Tk

HR

T (m

in)

Hyp

o D

ose

(L/d

)

Cl2

Dos

e/10

(mg/

L)Fr

ee C

l2 R

esid

'l (m

g/L)

C5. Chlorination Chlorine Dose Free Cl2 Residual Contact tank HRT-at ave flow -at decant flow Hypo dose

1 16118:Ken Hartley v2:28-Feb-14

Jimboomba WWTP Upgrade Mechanical & Electrical Requirements The Jimboomba Wastewater Treatment Plant is to be upgraded from 1500 EP to 2600 EP to enable it to handle an increasing load until the proposed Cedar Grove plant comes online around 2021. The upgrade may be implemented in two stages as follows: Stage1 (2100 EP): ¨ Influent screening upgrade. ¨ Increase in SBR aeration capacity. ¨ Upgrade of aeration and decanting controls to allow operation on a reduced 3-hour

cycle. ¨ Duplication of the chlorine contact tank and upgraded chlorination controls. Stage 2 (2600 EP): ¨ Raising of the SBR TWL by 225mm, giving a 50% increase in decanting volume. ¨ Doubling of decanter length from 3m to 6m. The upgraded plant flowsheet is shown in Figure 1 and the functional details are listed in Table 1.

Figure 1 Upgraded plant flowsheet.

SBR ContactorEffluentStorage P

Chlorine

Class C recycling95%ile E.coli

1000 cfu/100mL

Sewage

Overflow to river

Screen

Sludge

Contactor

Caustic Soda

2 16118:Ken Hartley v2:28-Feb-14

Table 1 Functional Details Item Existing

1500 EP Capacity, ADWF 315 kL/d Proposed Changes1 2600 EP Capacity, ADWF 550 kL/d

Process Units SBR: Geometry Surface area Volume at TWL Volume at LWL Max water depth Max decant depth Decant weir length Cycle time Decant Cl2 contact tank volume Chlorination capacity Effluent lagoon volume Sludge lagoon volume Drying bed area SBR Equipment Aeration system: Blowers Diffusers SOTR WAS pump Decanting weir Caustic soda dosing

Side walls: upper 1.2m vertical, lower 45deg 204 m2 618 kL 536 kL 4.0 m 0.4m 3m 4.8h (288 mins, 5 cycles/d) Continuous inflow, decant 20% of cycle time; max

decant 82 kL plus inflow during decant, total 115 kL 1 No. 17 kL 32 L/h of 125 gCl2/L NaOCl solution (4 kgCl2/h) 15 ML approx. 2 No. ea 280 kL 75 m2 2 No. ea 140 L/s high speed, 50 L/s slow speed Rehau fine pore membranes 35 kg/h per blower, HS (calc) 1 No. 3 L/s 3m long, max decant depth 0.40m Max dose rate 200 mgCaCO3/L at ADWF

Raise walls & TWL by 225mm 4.2 m 0.6m 6m 3h (180 mins, 8 cycles/d) Max decant volume increased by 50%. Above 3ADWF (1.65 ML/d) operate in settle mode with continuous decanter overflow. 3 No. 17 kL ea Dose 10 mgCl2/L at 7ADWF, 13 L NaOCl/h; provide effluent flow meter, flow-pacing of dose, monitoring of Cl2 residual at end of contact tanks. Free Cl2 residual required, 1.5 mg/L. Increase aeration capacity by 75%. 6m long, max decant depth 0.60m 50% soln; 2 kL tank; dosing pump 5 L/h max

1 M&E items shown in italics. Some controls may also need upgrades.



90-12-53 Date issued: 23/05/2014 Rev: 1

Appendix D Preliminary Options Matrix

Detailed Options Development - Matrix MethodCombination of Hydraulic and Biological Improvements to create options

hydraulic

With hydraulic controls

a) Do nothing b) Flow Balancing –

upstream pump

controls

c) Flow Balancing –

balance tank

b&c) Flow

Balancing – balance

tank + controlled

pumps

d) Increase through

plant capacity

d&b) Increase

through plant

capacity + controlled

pumps

d&b&c) Increase

through plant

capacity + controlled

pumps+balance tank

e&c) Wet weather

bypass + balance

tank

e&c&b) Wet

weather bypass +

controlled pumping +

balance tanks

f) Transfer flows to

Flagstone WWTP

PS VSD controls to RM min/ PWWF Y Y Y Y Y

balance tank Y Y Y Y

biological

i) Do nothing Y

ii) Sequential upgrade of the existing SBR process Y Y Y Y Y Y Y Y

iii) Upgrade SBR process to MBR process Y Y Y Y Y

iv) Add parallel SBR plant Y Y Y

v) Add parallel package plant Y Y Y Y Y

vi) Transfer flows to Flagstone WWTP Y

Preliminary assessment

Options description protects process

minimises poor WQ

for

lagoon/irrigation/

release quality meets objectives Expected cost comment

develop to final

options

i) Do nothing

a) Do nothingno hydraulic or biological upgrade N N N low not acceptable N (comparison only)

ii) Sequential upgrade of the existing SBR process

d&b) Increase through plant capacity + controlled

pumps SBR upgade for biological and hydraulic plus pump

controlsY Y Y

SBR u/g - 2M?

Pump controls -

0.05M?

smaller SBR tank and

weir - accomodate

52/44 L/s

Y

d&b&c) Increase through plant capacity + controlled

pumps+balance tankSBR upgade for biological and hydraulic plus balance

tank plus pump controlsY Y Y

SBR u/g - 2M?

Tank - 0.3M?

Pump controls -

0.05M?

optimise balance

tank and sbr size

(min 5*ADWF). May

be the same as ii-

b&c)

Y

e&c&b) Wet weather bypass + controlled pumping +

balance tanks

SBR upgrade biological

bypass to take flows > 3 or 5 ADWF, balance tank to

cater for smaller peaks to smooth flow, reduced

inflow peaks

Ypartly - does not

during peak flowsY

SBR u/g - 0.3M?

Bypass - 0.5M?

Tank - 0.1M?

smaller bypass and

tankY

iii) Upgrade SBR process to MBR process

iv) Add parallel SBR plant

b) Flow Balancing – upstream pump controls

New SBR -parallel to sbr, with pump controls Ypartly - does not

during peak flowsY

New SBR - 3M?

Pump controls -

0.05M?

SBRs - high peak

flows, alternate

operation

Y

v) Add parallel package plant

b) Flow Balancing – upstream pump controlsNew Package plant -parallel to sbr, with pump

controlsY

partly - does not

during peak flowsY

PP - 3M?

Pump controls -

0.05M?

new PP - high peak

flowsY

vi) Transfer flows to Flagstone WWTP



90-12-53 Date issued: 23/05/2014 Rev: 1

Appendix E Capital Cost and NPV

Planning Estimate ‐ 90‐12‐53

Jimboomba WWTP Capacity AssessmentRemarks

Item Description Unit Quantity Unit rate Amount 2014 2016 (original option 1.2)

Direct Cost Estimate

A‐2 Option 1.2 ‐ Existing SBR Upgrade + Small Balance

Tank

A‐2.1 General

Management & Supervision item 0.000 52,240.00$ ‐$ ‐$ ‐$ RC estimate

Site Establishment item 0.000 10,000.00$ ‐$ ‐$ ‐$ RC estimate

Total ‐ General ‐$ ‐$ ‐$

A‐2.2 Common SPS Control Modification Scope to all

Options

Install VSD Controls item 1.000 ‐$ ‐$ ‐$ ‐$ included in other project

Install Coms Control item 1.000 ‐$ ‐$ ‐$ ‐$ included in other project

Wet Weather Pumping ‐ SPS 1 modification works item 1.000 10,000.00$ 10,000.00$ 10,000.00$ ‐$ allowance for control modifications (plc

programming, scada alarms etc)

Total ‐ Common Scope to all Options 10,000.00$ 10,000.00$ ‐$

A‐2.3 Balance Tank ‐ Small

Transfer existing 30kL concrete tank to site (from

loganholme)

item 1.000 2,050.00$ 2,050.00$ 2,050.00$ ‐$ allowance for truck hire/ movement of tank

Supply and Install Balance Tank foundation item 1.000 4,832.00$ 4,832.00$ 4,832.00$ ‐$ RC estimate

Supply and Install return pump (10L/s) item 1.000 20,000.00$ 20,000.00$ 20,000.00$ ‐$ allowance, includes electricals, foundation etc

Balance tank inlet pipe ‐ DN 225 x 3m item 1.000 660.00$ 660.00$ 660.00$ ‐$ RC estimate

Balance tank overflow pipe ‐ DN 225 x 12m item 1.000 1,360.00$ 1,360.00$ 1,360.00$ ‐$ RC estimate

Balance tank return pipe ‐ DN 150 x 3m item 1.000 600.00$ 600.00$ 600.00$ ‐$ RC estimate

Total ‐ Balance Tank ‐ Small 29,502.00$ 29,502.00$ ‐$

A‐2.4 Treatment Plant Upgrade

SBR wall increase by 225mm item 1.000 29,860.00$ 29,860.00$ 29,860.00$ ‐$ RC estimate

Replacement Weir 3m x 0.885m (inward folding) +

motor

(cost is for 6m weir)

item 1.000 $150,000.00 150,000.00$ 150,000.00$ ‐$ Aquatec Maxcon ‐ costed a 6m weir at $200k,

prorated by length +50%

Discharge Pit ‐ 2 nos for Weir 2 & 3 no 2.000 $5,633.00 11,266.00$ 11,266.00$ ‐$ RC estimate

Supply and Install ‐ weir 2 item 1.000 $75,000.00 75,000.00$ 75,000.00$ ‐$ Aquatec Maxcon ‐ costed a 6m weir at $200k,


Supply and Install ‐ weir 3 item 1.000 $75,000.00 75,000.00$ 75,000.00$ ‐$ Aquatec Maxcon ‐ costed a 6m weir at $200k,


wier 2 outlet pipe 300mm 3m, + Tee item 1.000 $5,200.00 5,200.00$ 5,200.00$ ‐$ RC estimate

wier 3 outlet pipe 300mm 1m + Tee item 1.000 $2,400.00 2,400.00$ 2,400.00$ ‐$ RC estimate

Replace/ upgrade existing aeration system and

controls

item 1.000 $250,000.00 250,000.00$ ‐$ 250,000.00$ Aquatec Maxcon

Install pH dosing (with automated controls) item 1.000 $50,000.00 50,000.00$ ‐$ 50,000.00$ Aquatec Maxcon

Install Alum dosing (with automated controls) item 1.000 $50,000.00 50,000.00$ ‐$ 50,000.00$ Aquatec Maxcon

Small Chemical Bund item 3.000 $6,064.00 18,192.00$ ‐$ 18,192.00$ RC estimate

Inlet Screen Pit modifications (additional) item 1.000 13,688.00$ 13,688.00$ 13,688.00$ ‐$ allowance

Automated Valves on Sludge overflow item 2.000 6,000.00$ 12,000.00$ 12,000.00$ ‐$ allowance

Flowmeter on inlet main item 1.000 10,000.00$ 10,000.00$ 10,000.00$ ‐$ allowance

Scada upgrade item 1.000 15,000.00$ 15,000.00$ 5,065.21$ 9,934.79$ allowance for general scada modifications for

new infrastructure and operational changes

Additional Switchboard item 1.000 80,000.00$ 80,000.00$ ‐$ 80,000.00$

New Switchboard and Blower Room/Building item 1.000 45,500.00$ 45,500.00$ ‐$ 45,500.00$

Electrical works, trenching and civil works (including

minor wks)

item 1.000 200,000.00$ 200,000.00$ 67,536.12$ 132,463.88$ Aquatec Maxcon

Total ‐ Treatment Plant Upgrade 1,093,106.00$ 457,015.33$ 636,090.67$

A‐2.5 Chlorine Contact Tank

New Cl dosing system item 1.000 50,000.00$ 50,000.00$ ‐$ 50,000.00$ Aquatec Maxcon

New Cl dosing storage item 0.000 ‐$ ‐$ ‐$ ‐$

Construct new Tank 34kL item 1.000 61,716.00$ 61,716.00$ ‐$ 61,716.00$ RC estimate

Construct new effluent manhole and short 225dia

pipe

item 1.000 10,000.00$ 10,000.00$ ‐$ 10,000.00$ allowance

Relocate algae toxin removal filter item 1.000 10,300.00$ 10,300.00$ ‐$ 10,300.00$ allowance for truck hire/ movement of tank

Total ‐ Chlorine Contact Tank 132,016.00$ ‐$ 132,016.00$

TOTAL ‐ OPTION 1.2 1,264,624.00$ 496,517.33$ 768,106.67$

Total Project Cost 0.47 1,858,997.28$ 729,880.48$ 1,129,116.80$

Total Project Cost plus Contingency 0.3 2,416,696.46$ 948,844.62$ 1,467,851.84$

Option 1



Item Description Unit Quantity Unit rate Amount 2014 2016 2017 (original option 2.1)


B Option 2.1 ‐ Existing SBR Upgrade + Large Balance

Tank

B.1 General

Management & Supervision item 0.000 52,240.00$ ‐$ ‐$ ‐$ ‐$ RC estimate

Site Establishment item 0.000 10,000.00$ ‐$ ‐$ ‐$ ‐$ RC estimate

Total ‐ General ‐$ ‐$ ‐$ ‐$

B.2 Common SPS Control Modification Scope to all

Options

Install VSD Controls item 1.000 ‐$ ‐$ ‐$ ‐$ ‐$ included in other project

Install Coms Control item 1.000 ‐$ ‐$ ‐$ ‐$ ‐$ included in other project

Wet Weather Pumping ‐ SPS 1 and 2 program

modification

item 1.000 10,000.00$ 10,000.00$ 10,000.00$ ‐$ ‐$ allowance for control modifications (plc


Total ‐ Common Scope to all Options 10,000.00$ 10,000.00$ ‐$ ‐$

B.3 Balance Tank ‐ Large

Supply and Install 250kL Balance Tank including

concrete base

item 1.000 115,208.25$ 115,208.25$ 115,208.25$ ‐$ ‐$ RC estimate

Supply and Install return pump (30L/s) item 1.000 20,000.00$ 20,000.00$ 20,000.00$ ‐$ ‐$ allowance, includes electricals, foundation etc

Balance tank inlet pipe ‐ DN 225 x 3m item 1.000 660.00$ 660.00$ 660.00$ ‐$ ‐$ RC estimate

Balance tank overflow pipe ‐ DN 225 x 12m item 1.000 1,360.00$ 1,360.00$ 1,360.00$ ‐$ ‐$ RC estimate

Balance tank return pipe ‐ DN 150 x 3m item 1.000 600.00$ 600.00$ 600.00$ ‐$ ‐$ RC estimate

Total ‐ Balance Tank ‐ Large 137,828.25$ 137,828.25$ ‐$ ‐$

B.4 Treatment Plant Upgrade

SBR wall increase by 225mm item 1.000 29,860.00$ 29,860.00$ ‐$ ‐$ 29,860.00$ RC estimate


motor

item 1.000 $150,000.00 150,000.00$ ‐$ ‐$ 150,000.00$ Aquatec Maxcon ‐ costed a 6m weir at $200k,


Discharge Pit ‐ 2 nos for Weir 2 & 3 no 2.000 $5,633.00 11,266.00$ ‐$ ‐$ 11,266.00$ RC estimate

Supply and Install ‐ weir 2 item 1.000 $75,000.00 75,000.00$ ‐$ ‐$ 75,000.00$ Aquatec Maxcon ‐ costed a 6m weir at $200k,




wier 2 outlet pipe 300mm 3m, + Tee item 1.000 $5,200.00 5,200.00$ ‐$ ‐$ 5,200.00$ RC estimate

wier 3 outlet pipe 300mm 1m + Tee item 1.000 $2,400.00 2,400.00$ ‐$ ‐$ 2,400.00$ RC estimate


controls

item 1.000 $250,000.00 250,000.00$ ‐$ 250,000.00$ ‐$ Aquatec Maxcon

Install pH dosing (with automated controls) item 1.000 $50,000.00 50,000.00$ ‐$ 50,000.00$ ‐$ Aquatec Maxcon

Install Alum dosing (with automated controls) item 1.000 $50,000.00 50,000.00$ ‐$ 50,000.00$ ‐$ Aquatec Maxcon

Small Chemical Bund item 3.000 $6,064.00 18,192.00$ ‐$ 18,192.00$ ‐$ RC estimate

Inlet Screen Pit modifications (additional) item 1.000 13,688.00$ 13,688.00$ 13,688.00$ ‐$ ‐$ allowance

Automated Valves on Sludge overflow item 2.000 6,000.00$ 12,000.00$ 12,000.00$ ‐$ ‐$ allowance

Flowmeter on inlet main item 1.000 10,000.00$ 10,000.00$ 10,000.00$ ‐$ ‐$ allowance

Scada upgrade item 1.000 15,000.00$ 15,000.00$ 2,507.58$ 7,134.62$ 5,357.80$ allowance for general scada modifications for


Additional Switchboard item 1.000 80,000.00$ 80,000.00$ ‐$ 80,000.00$ ‐$

New Switchboard and Blower Room/Building item 1.000 45,500.00$ 45,500.00$ ‐$ 45,500.00$ ‐$


minor wks)

item 1.000 200,000.00$ 200,000.00$ 33,434.41$ 95,128.26$ 71,437.34$ Aquatec Maxcon

Total ‐ Treatment Plant Upgrade 1,093,106.00$ 71,629.99$ 595,954.88$ 425,521.14$

B.5 Chlorine Contact Tank

New Cl dosing system item 1.000 50,000.00$ 50,000.00$ ‐$ ‐$ 50,000.00$ Aquatec Maxcon

New Cl dosing storage item 0.000 ‐$ ‐$ ‐$ ‐$ ‐$

Construct new Tank 34kl item 1.000 61,716.00$ 61,716.00$ ‐$ ‐$ 61,716.00$ RC estimate


pipe

item 1.000 10,000.00$ 10,000.00$ ‐$ ‐$ 10,000.00$ allowance

Relocate algae toxin removal filter item 1.000 10,300.00$ 10,300.00$ ‐$ ‐$ 10,300.00$ allowance for truck hire/ movement of tank

Total ‐ Chlorine Contact Tank 132,016.00$ ‐$ ‐$ 132,016.00$

TOTAL ‐ OPTION 2.1 1,372,950.25$ 219,458.24$ 595,954.88$ 557,537.14$

Total Project Cost 0.47 2,018,236.87$ 322,603.61$ 876,053.67$ 819,579.59$

Total Project Cost plus Contingency 0.3 2,623,707.93$ 419,384.70$ 1,138,869.77$ 1,065,453.47$

Option 2



Item Description Unit Quantity Unit rate Amount 2014 2016 2017 (original option 3.1)


D Option 3.1 ‐Existing SBR Upgrade + Small Balance

Tank + Wet Weather Bypass to CCT

D.1 General

Management & Supervision item 0.000 52,240.00$ ‐$ ‐$ ‐$ ‐$ RC estimate

Site Establishment item 0.000 10,000.00$ ‐$ ‐$ ‐$ ‐$ RC estimate

Total ‐ General ‐$ ‐$ ‐$ ‐$

D.2 Common SPS Control Modification Scope to all

Options

Install VSD Controls item 1.000 ‐$ ‐$ ‐$ ‐$ ‐$ included in other project

Install Coms Control item 1.000 ‐$ ‐$ ‐$ ‐$ ‐$ included in other project

Wet Weather Pumping ‐ SPS 1 modification works item 1.000 10,000.00$ 10,000.00$ 10,000.00$ ‐$ ‐$ allowance for control modifications (plc


Total ‐ Common Scope to all Options 10,000.00$ 10,000.00$ ‐$ ‐$

D.3 Balance Tank ‐ Small


loganholme)

item 1.000 2,050.00$ 2,050.00$ 2,050.00$ ‐$ ‐$ allowance for truck hire/ movement of tank

Concrete Base for Existing Balance Tank item 1.000 4,832.00$ 4,832.00$ 4,832.00$ ‐$ ‐$ RC estimate

Supply and Install return pump (10L/s) item 1.000 20,000.00$ 20,000.00$ 20,000.00$ ‐$ ‐$ allowance, includes electricals, foundation etc

Balance tank inlet pipe ‐ DN 225 x 3m item 1.000 660.00$ 660.00$ 660.00$ ‐$ ‐$ RC estimate

Balance tank return pipe ‐ DN 150 x 3m item 1.000 600.00$ 600.00$ 600.00$ ‐$ ‐$ RC estimate

Total ‐ Balance Tank ‐ Small 28,142.00$ 28,142.00$ ‐$ ‐$

D.4 WW Bypass pipe

WW bypass to CCT ‐ DN225 x 30m item 1.000 4,860.00$ 4,860.00$ 4,860.00$ ‐$ ‐$ RC estimate

Total ‐ Lagoon as Balance Tank 4,860.00$ 4,860.00$ ‐$ ‐$

D.5 Treatment Plant Upgrade

SBR wall increase by 225mm item 1.000 29,860.00$ 29,860.00$ ‐$ ‐$ 29,860.00$ RC estimate


motor

item 1.000 $150,000.00 150,000.00$ ‐$ ‐$ 150,000.00$ Aquatec Maxcon ‐ costed a 6m weir at $200k,


Discharge Pit ‐ 2 nos for Weir 2 & 3 no 2.000 $5,633.00 11,266.00$ ‐$ ‐$ 11,266.00$ RC estimate





wier 2 outlet pipe 300mm 3m, + Tee item 1.000 $5,200.00 5,200.00$ ‐$ ‐$ 5,200.00$ RC estimate

wier 3 outlet pipe 300mm 1m + Tee item 1.000 $2,400.00 2,400.00$ ‐$ ‐$ 2,400.00$ RC estimate


controls

item 1.000 $250,000.00 250,000.00$ ‐$ 250,000.00$ ‐$ Aquatec Maxcon

Install pH dosing (with automated controls) item 1.000 $50,000.00 50,000.00$ ‐$ 50,000.00$ ‐$ Aquatec Maxcon

Install Alum dosing (with automated controls) item 1.000 $50,000.00 50,000.00$ ‐$ 50,000.00$ ‐$ Aquatec Maxcon

Small Chemical Bund item 1.000 $6,064.00 6,064.00$ ‐$ 6,064.00$ ‐$ RC estimate

Inlet Screen Pit modifications (additional) item 3.000 13,688.00$ 41,064.00$ 41,064.00$ ‐$ ‐$ allowance

Automated Valves on Sludge overflow item 2.000 6,000.00$ 12,000.00$ 12,000.00$ ‐$ ‐$ allowance

Flowmeter on inlet main item 1.000 10,000.00$ 10,000.00$ 10,000.00$ ‐$ ‐$ allowance

Scada upgrade item 1.000 15,000.00$ 15,000.00$ 1,570.54$ 7,872.86$ 5,556.60$ allowance for general scada modifications for


Additional Switchboard item 1.000 80,000.00$ 80,000.00$ ‐$ 80,000.00$ ‐$

New Switchboard and Blower Room/Building item 1.000 45,500.00$ 45,500.00$ ‐$ 45,500.00$ ‐$


minor wks)

item 1.000 200,000.00$ 200,000.00$ 20,940.50$ 104,971.48$ 74,088.02$ Aquatec Maxcon

Total ‐ Treatment Plant Upgrade 1,108,354.00$ 85,575.04$ 594,408.34$ 428,370.63$

D.6 Chlorine Contact Tank

New Cl dosing system item 1.000 50,000.00$ 50,000.00$ ‐$ ‐$ 50,000.00$ Aquatec Maxcon

New Cl dosing storage item 1.000 5,000.00$ 5,000.00$ ‐$ ‐$ 5,000.00$

Construct new Tank 34kL item 1.000 61,716.00$ 61,716.00$ ‐$ ‐$ 61,716.00$ RC estimate


pipe

item 1.000 10,000.00$ 10,000.00$ ‐$ ‐$ 10,000.00$ allowance

Relocate algae toxin removal filter item 1.000 10,300.00$ 10,300.00$ ‐$ ‐$ 10,300.00$ allowance for truck hire/ movement of tank

Total ‐ Chlorine Contact Tank 137,016.00$ ‐$ ‐$ 137,016.00$

TOTAL ‐ OPTION 3.1 1,288,372.00$ 128,577.04$ 594,408.34$ 565,386.63$

Total Project Cost 0.47 1,893,906.84$ 189,008.24$ 873,780.26$ 831,118.34$

Total Project Cost plus Contingency 0.3 2,462,078.89$ 245,710.71$ 1,135,914.33$ 1,080,453.84$

Option 3





G Option 4.1 ‐ New parallel SBR + pump controls

G.1 General




G.2 Common SPS Control Modification Scope to all

Options



Wet Weather Pumping ‐ SPS 1 modification works item 1.000 10,000 10,000 10,000.00$ ‐$ allowance for control modifications (plc



G.3 Treatment Plant Upgrades

SBR 2 Tank 618kL(duplicate) ‐ Concrete Structure

ONLY

item 1.000 237,329.00$ 237,329.00$ 237,329.00$ ‐$ RC estimate


motor

item 1.000 150,000.00$ 150,000.00$ 150,000.00$ ‐$ Aquatec Maxcon ‐ costed a 6m weir at $200k,



Plant 2 inlet Pipe ‐ DN 300 x 12m item 1.000 22,600.00$ 22,600.00$ 22,600.00$ ‐$ RC estimate

Plant 2 outlet Pipe ‐ DN 300 x 8m item 1.000 2,000.00$ 2,000.00$ 2,000.00$ ‐$ RC estimate

WAS Pipe ‐ DN80mm x 40m item 1.000 2,260.00$ 2,260.00$ ‐$ 2,260.00$ RC estimate

WAS Pump 2 (3 L/s) item 1.000 20,000.00$ 20,000.00$ ‐$ 20,000.00$ allowance, includes foundation etc

WAS Pump 2 delivery pipe ‐ DN80mm x 2m item 1.000 145.00$ 145.00$ ‐$ 145.00$ RC estimate

WAS Pump 2 suction pipe ‐ DN80mm x 3m item 1.000 160.00$ 160.00$ ‐$ 160.00$ RC estimate

SBR Tank 2 Aeration System and Controls item 1.000 250,000.00$ 250,000.00$ ‐$ 250,000.00$ Aquatec Maxcon

Site road relocation (say 15m *4m) m2 120.000 100.00$ 12,000.00$ 12,000.00$ ‐$ RC estimate

Install pH dosing(with automated controls) item 1.000 50,000.00$ 50,000.00$ ‐$ 50,000.00$ Aquatec Maxcon

Install Alum dosing (with automated controls) item 1.000 50,000.00$ 50,000.00$ ‐$ 50,000.00$ Aquatec Maxcon

Small Chemical Bund item 3.000 6,064.00$ 18,192.00$ ‐$ 18,192.00$ RC estimate









minor wks)


Total ‐ Treatment Plant Upgrades 1,210,874.00$ 572,128.28$ 638,745.72$

G.4 Chlorine Contact Tank





pipe

item 1.000 10,000.00$ 10,000.00$ ‐$ 10,000.00$ allowance



TOTAL ‐ OPTION 4.1 1,352,890.00$ 582,128.28$ 770,761.72$


Total Project Cost plus Contingency 0.3 2,585,372.79$ 1,112,447.13$ 1,472,925.66$

Option 4





F Option 4.2 ‐ New package plant(parallel to SBR) +

pump controls

F.1 General




F.2 Common SPS Control Modification Scope to all

Options



Wet Weather Pumping ‐ SPS 1 and 2 program

modification

item 1.000 10,000.00$ 10,000.00$ 10,000.00$ ‐$ allowance for control modifications (plc



F.3 Treatment Plant Upgrades

Package Plant 1 500 EP item 1.000 576,354.56$ 576,354.56$ 576,354.56$ ‐$ supplier estimate

Package Plant 1 Foundation item 1.000 64,884.00$ 64,884.00$ 64,884.00$ ‐$ RC estimate

Package Plant 2 600 EP item 1.000 677,407.69$ 677,407.69$ ‐$ 677,407.69$ supplier estimate

Package Plant 2 Foundation item 1.000 64,884.00$ 64,884.00$ ‐$ 64,884.00$ RC estimate

Plant 2 inlet Pipe ‐ DN 300 x 12m item 1.000 22,600.00$ 22,600.00$ 22,600.00$ ‐$ RC estimate

Plant 2 outlet Pipe ‐ DN 300 x 8m item 1.000 2,000.00$ 2,000.00$ 2,000.00$ ‐$ RC estimate

Plant 3 inlet Pipe ‐ DN 225 x 9m item 1.000 13,600.00$ 13,600.00$ ‐$ 13,600.00$ RC estimate

Plant 3 outlet Pipe ‐ DN 225 x 7m item 1.000 2,000.00$ 2,000.00$ ‐$ 2,000.00$ RC estimate

WAS Pipe ‐ DN80mm x 40m item 1.000 2,000.00$ 2,000.00$ 2,000.00$ ‐$ RC estimate

WAS Pump 2 (3 L/s) item 1.000 20,000.00$ 20,000.00$ 20,000.00$ ‐$ allowance, includes foundation etc

WAS Pump 2 delivery pipe ‐ DN80mm x 2m item 1.000 145.00$ 145.00$ 145.00$ ‐$ RC estimate

WAS Pump 2 suction pipe ‐ DN80mm x 3m item 1.000 160.00$ 160.00$ 160.00$ ‐$ RC estimate


Inlet Screen Pit modifications (additional) item 1.000 13,688.00$ 13,688.00$ ‐$ 13,688.00$ allowance








minor wks)


Total ‐ Treatment Plant Upgrades 1,728,287.24$ 758,014.02$ 970,273.22$

F.4 Chlorine Contact Tank


New Cl dosing storage item 0.000 ‐$ ‐$ ‐$ ‐$ Awaiting costs



pipe

item 1.000 10,000.00$ 10,000.00$ ‐$ 10,000.00$ allowance



TOTAL ‐ OPTION 4.2 1,855,781.83$ 768,014.02$ 1,087,767.81$

Total Project Cost 0.47 2,727,999.29$ 1,128,980.61$ 1,599,018.68$

Total Project Cost plus Contingency 0.3 3,546,399.08$ 1,467,674.80$ 2,078,724.28$

Option 5



Item Description Unit Quantity Unit rate Amount 2014 2016 (Option 4 + balance tank)


G preferred option ‐ New parallel SBR + pump

controls+ BALANCE TANK

G.1 General




G.2 Common SPS Control Modification Scope to all

Options



Wet Weather Pumping ‐ SPS 1 modification works item 1.000 10,000 10,000 10,000.00$ ‐$ allowance for control modifications (plc



A‐2.3 Balance Tank ‐ Small


loganholme)

item 1.000 2,050.00$ 2,050.00$ 2,050.00$ ‐$ RC estimate

Supply and Install Balance Tank foundation item 1.000 4,832.00$ 4,832.00$ 4,832.00$ ‐$ RC estimate


Balance tank inlet pipe ‐ DN 225 x 3m item 1.000 660.00$ 660.00$ 660.00$ ‐$ RC estimate

Balance tank overflow pipe ‐ DN 225 x 12m item 1.000 1,360.00$ 1,360.00$ 1,360.00$ ‐$ RC estimate

Balance tank return pipe ‐ DN 150 x 3m item 1.000 600.00$ 600.00$ 600.00$ ‐$ RC estimate

Total ‐ Balance Tank ‐ Small 29,502.00$ 29,502.00$ ‐$

G.3 Treatment Plant Upgrades

SBR 2 Tank 618kL(duplicate) ‐ Concrete Structure

ONLY

item 1.000 237,329.00$ 237,329.00$ ‐$ 237,329.00$ RC estimate


motor

item 1.000 150,000.00$ 150,000.00$ ‐$ 150,000.00$ Aquatec Maxcon

Plant 2 inlet Pipe ‐ DN 300 x 12m item 1.000 22,600.00$ 22,600.00$ ‐$ 22,600.00$ RC estimate

Plant 2 outlet Pipe ‐ DN 300 x 8m item 1.000 2,000.00$ 2,000.00$ ‐$ 2,000.00$ RC estimate

WAS Pipe ‐ DN80mm x 40m item 1.000 2,260.00$ 2,260.00$ ‐$ 2,260.00$ RC estimate

WAS Pump 2 (3 L/s) item 1.000 20,000.00$ 20,000.00$ ‐$ 20,000.00$ allowance, includes foundation etc

WAS Pump 2 delivery pipe ‐ DN80mm x 2m item 1.000 145.00$ 145.00$ ‐$ 145.00$ RC estimate

WAS Pump 2 suction pipe ‐ DN80mm x 3m item 1.000 160.00$ 160.00$ ‐$ 160.00$ RC estimate

SBR Tank 2 Aeration System and Controls item 1.000 250,000.00$ 250,000.00$ ‐$ 250,000.00$ Aquatec Maxcon

Site road relocation (say 15m *4m) m2 120.000 100.00$ 12,000.00$ ‐$ 12,000.00$ RC estimate

Install pH dosing(with automated controls) item 1.000 50,000.00$ 50,000.00$ ‐$ 50,000.00$ Aquatec Maxcon

Install Alum dosing (with automated controls) item 1.000 50,000.00$ 50,000.00$ ‐$ 50,000.00$ Aquatec Maxcon





Scada upgrade item 1.000 15,000.00$ 15,000.00$ ‐$ 15,000.00$ allowance for general scada modifications for





minor wks)


Total ‐ Treatment Plant Upgrades 1,190,874.00$ 48,625.12$ 1,142,248.88$

G.4 Chlorine Contact Tank





pipe

item 1.000 10,000.00$ 10,000.00$ ‐$ 10,000.00$ allowance



TOTAL ‐ OPTION 4.1 + small balance tank 1,362,392.00$ 88,127.12$ 1,274,264.88$


Total Project Cost plus Contingency 0.3 2,603,531.11$ 168,410.92$ 2,435,120.19$

Preferred Option: Option 4.1 + balance tank

90‐12‐53 Jimboomba WWTP Capacity Assessment ‐ NPV Tables Including Sensitivity Assessment

NPV Comparison Table

OPTIONS NPV Capital Investment RANK OPTIONS NPVVariation

from lowest

Percentage Variation

from lowest

Capital

Investment

Variation

from lowest


from lowest

Option 1 $12,665,380 $2,416,696 4 Option 1 $12,665,380 $337,079 3.1% $2,416,696 $0 0.0%Option 2 $12,778,156 $2,623,708 5 Option 2 $12,778,156 $449,856 4.2% $2,623,708 $207,011 1.9%Option 3 $12,575,630 $2,462,079 3 Option 3 $12,575,630 $247,329 2.3% $2,462,079 $45,382 0.4%Option 4 $12,328,301 $2,585,373 1 Option 4 $12,328,301 $0 0.0% $2,585,373 $168,676 1.6%Option 5 $13,921,010 $3,546,399 6 Option 5 $13,921,010 $1,592,710 14.8% $3,546,399 $1,129,703 10.5%Preferred Option $12,502,235 $2,603,531 2 Preferred Option $12,502,235 $173,934 1.6% $2,603,531 $186,835 1.7%



from lowest


from lowest

Capital

Investment

Variation

from lowest


from lowest

Option 1 $13,770,203 $2,416,696 4 Option 1 $13,770,203 $1,377,042 12.8% $2,416,696 $0 0.0%Option 2 $13,943,489 $2,623,708 5 Option 2 $13,943,489 $1,550,328 14.4% $2,623,708 $207,011 1.9%Option 3 $13,759,042 $2,462,079 3 Option 3 $13,759,042 $1,365,881 12.7% $2,462,079 $45,382 0.4%Option 4 $12,393,161 $2,585,373 1 Option 4 $12,393,161 $0 0.0% $2,585,373 $168,676 1.6%Option 5 $15,000,403 $3,546,399 6 Option 5 $15,000,403 $2,607,242 24.3% $3,546,399 $1,129,703 10.5%Preferred Option $12,465,821 $2,603,531 2 Preferred Option $12,465,821 $72,660 0.7% $2,603,531 $186,835 1.7%



from lowest


from lowest

Capital

Investment

Variation

from lowest


from lowest

Option 1 $13,365,420 $2,416,696 4 Option 1 $13,365,420 $106,980 1.0% $2,416,696 $0 0.0%Option 2 $13,449,761 $2,623,708 5 Option 2 $13,449,761 $191,320 1.8% $2,623,708 $207,011 1.9%Option 3 $13,258,440 $2,462,079 1 Option 3 $13,258,440 $0 0.0% $2,462,079 $45,382 0.4%Option 4 $13,264,608 $2,585,373 2 Option 4 $13,264,608 $6,168 0.1% $2,585,373 $168,676 1.6%Option 5 $14,597,242 $3,546,399 6 Option 5 $14,597,242 $1,338,801 12.5% $3,546,399 $1,129,703 10.5%Preferred Option $13,293,636 $2,603,531 3 Preferred Option $13,293,636 $35,196 0.3% $2,603,531 $186,835 1.7%



from lowest


from lowest

Capital

Investment

Variation

from lowest


from lowest

Option 1 $11,890,921 $2,416,696 5 Option 1 $11,890,921 $444,275 4.1% $2,416,696 $0 0.0%Option 2 $11,855,958 $2,623,708 4 Option 2 $11,855,958 $409,312 3.8% $2,623,708 $207,011 1.9%Option 3 $11,635,445 $2,462,079 3 Option 3 $11,635,445 $188,799 1.8% $2,462,079 $45,382 0.4%Option 4 $11,446,646 $2,585,373 1 Option 4 $11,446,646 $0 0.0% $2,585,373 $168,676 1.6%Option 5 $13,250,577 $3,546,399 6 Option 5 $13,250,577 $1,803,931 16.8% $3,546,399 $1,129,703 10.5%Preferred Option $11,531,687 $2,603,531 2 Preferred Option $11,531,687 $85,041 0.8% $2,603,531 $186,835 1.7%



from lowest


from lowest

Capital

Investment

Variation

from lowest


from lowest

Option 1 $19,523,200 $2,416,696 2 Option 1 $19,523,200 $120,468 1.1% $2,416,696 $0 0.0%Option 2 $19,747,813 $2,623,708 3 Option 2 $19,747,813 $345,082 3.2% $2,623,708 $207,011 1.9%Option 3 $19,402,731 $2,462,079 1 Option 3 $19,402,731 $0 0.0% $2,462,079 $45,382 0.4%Option 4 $20,270,423 $2,585,373 4 Option 4 $20,270,423 $867,692 8.1% $2,585,373 $168,676 1.6%Option 5 $21,504,094 $3,546,399 6 Option 5 $21,504,094 $2,101,363 19.6% $3,546,399 $1,129,703 10.5%Preferred Option $20,653,275 $2,603,531 5 Preferred Option $20,653,275 $1,250,544 11.6% $2,603,531 $186,835 1.7%

NPV Summary Table ‐ Population Sensitivity ‐ D: 2%

Growth

NPV Summary Table ‐ Population Sensitivity ‐ A: +400 EP

NPV Summary Table ‐ Population Sensitivity ‐ B: 10%

Growth

NPV Summary Table ‐ Population sensitivity ‐ C: 5%

Growth

NPV Summary Table ‐ 25 yr

LOGAN WATER ALLIANCE JIMBOOMBA WWTP ... WWTP Capacity Assessment and Staging Plan Document Number:...

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