Contents...Water Production Flow Enhancement Engineer’s Report‐ Oct 2016 1 Chapter 1 –...

Water Production Flow Enhancement Engineer’s Report‐ Oct 2016

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TableofContents

Table of Contents .......................................................................................................................................... ii

Chapter 1 – Introduction ........................................................................................................................... 1

1.1 Background ..................................................................................................................................... 1

1.2 Project Description and Objective .................................................................................................. 1

Chapter 2 – OCSD Wastewater Flows ....................................................................................................... 4

2.1 OCSD Treatment Plant No. 2 – Huntington Beach .......................................................................... 4

2.2 Projected Secondary Effluent Flow Rates ....................................................................................... 4

Chapter 3 ‐ Water Production Flow Enhancement Project Description ................................................... 6

Chapter 4 – Financial Analysis ................................................................................................................. 10

4.1 Capital Cost of Project ................................................................................................................... 10

4.2 Annual Operation and Maintenance Costs ................................................................................... 10

4.3 Potential Sources of Financing ...................................................................................................... 11

4.4 Projected Unit Cost of Water Production Flow Enhancement Project Water .............................. 11

Chapter 5 – Project Implementation ...................................................................................................... 13

5.1 CEQA and NEPA Requirements ..................................................................................................... 13

5.2 Institutional Agreements .............................................................................................................. 13

5.3 Regulatory Approvals .................................................................................................................... 13

5.4 Sequencing of Project Activities and Schedule ............................................................................. 13

5.5 Financial Impact to OCWD ............................................................................................................ 14

5.6 Recommendation .......................................................................................................................... 14


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Chapter1–IntroductionThe Orange County Water District (OCWD) began operating the Groundwater Replenishment

System (GWRS), located in Fountain Valley, California, in 2008. The 2008 GWRS facility

consisted of a 70 million gallon per day (MGD) advanced water treatment facility (AWTF), a 13

mile GWRS pipeline, and an expansion of OCWD’s Talbert Seawater Barrier Injection Wells. The

original AWTF and pipeline projects were designed and constructed for an ultimate treatment

and conveyance capacity of 130 MGD. The original GWRS design intent was to expand the

GWRS facility in two phases – an initial expansion of an additional 30 MGD of treatment

capacity and a final expansion of another 30 MGD of treatment capacity. The GWRS Initial

Expansion Project was completed in June 2015 and allows the AWTF to produce 100 MGD of

purified water for groundwater injection and recharge. The GWRS Final Expansion Project will

include facilities required to upgrade the AWTF treatment capacity to produce 130 MGD of

purified water for groundwater recharge. The recently completed feasibility study for the GWRS

Final Expansion Project recommended the implementation of a flow equalization tank to

maximize the daily GWRS water production. This Engineer’s Report evaluates this Water

Production Flow Enhancement Project.

1.1BackgroundThe OCWD manages the groundwater basin in northern and central Orange County, California

by protecting, monitoring, and recharging the groundwater basin. Northern and central Orange

County cities and water agencies (Producers) pump approximately 75% of their water demand

from the groundwater basin to supply potable water to homes and businesses. The source

water for OCWD’s groundwater recharge currently comes from Santa Ana River base flows and

storm flows, purified recycled water from GWRS, incidental recharge, and imported water from

Metropolitan Water District (MWD).

The AWTF as part of GWRS treats OCSD secondary effluent to drinking water standards and

uses the purified water for both injection and percolation, through injection wells and recharge

basins, as source water to replenish the groundwater basin’s drinking water supplies. Figure 1

shows the GWRS existing facilities.

1.2ProjectDescriptionandObjectiveThe AWTF will receive 174 MGD of secondary effluent from both of the Orange County

Sanitation District (OCSD) wastewater treatment plants and have the capacity to produce 130

MGD of purified water for recharge as part of the GWRS Final Expansion Project. The AWTF

treats the secondary effluent with microfiltration, reverse osmosis and ultraviolet light to

produce purified water for groundwater recharge.

Figure 1 – Existing OCWD Facilities


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The inflow of the secondary effluent source water to GWRS varies throughout the day. On

average, the influent secondary effluent for GWRS could vary between 180 MGD during the day

to 60 MGD at night. Currently the GWRS facility does not have the ability to capture secondary

effluent flows above 135 MGD. Therefore, these peak flows during the day are wasted and not

recycled through GWRS. The purpose of the Water Production Flow Enhancement Project is to

capture and store these day time peak flows in a storage tank. The storage tank will be

designed to allow this stored secondary effluent to be fed to GWRS at night during OCSD low

flow periods to maximize treatment through GWRS.

The AWTF currently uses flow equalization tanks (i.e. storage tanks) for the secondary effluent

from OCSD’s Plant No. 1 adjacent to the GWRS facility. However, for the GWRS Final Expansion

Project, secondary effluent from OCSD’s Plant No. 2 in Huntington Beach is required. Figure 2

shows an aerial with both of OCSD’s treatment plants and the GWRS facility. This Flow

Equalization Tank Project will be designed to store the peak secondary effluent flows from

OCSD’s Plant No. 2 to increase production of the GWRS Final Expansion facility.


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Figure 2 – OCSD Treatment Plants and GWRS Facility Map

1.2.1SecondaryEffluentReuseStudy,SP‐173The Secondary Effluent Reuse Study, (SP‐173) is a jointly funded study by OCWD and OCSD to

evaluate the feasibility of recycling the majority of OCSD’s secondary effluent for GWRS Final

Expansion Project. CDM Smith and Brown and Caldwell completed the study in July 2016. The

SP‐173 study evaluated numerous alternatives for obtaining the required secondary effluent for

GWRS, to segregating non‐reclaimable flows at OCSD, to conveying the secondary effluent

flows to GWRS, and to maximize the secondary effluent flow to GWRS. The study incorporated

an alternatives analysis approach using ‘Criteria Decision Plus’ to evaluate numerous

alternatives in order to recommend the optimal project implementation plan for the GWRS

Final Expansion. This study also evaluated the design criteria for the flow equalization tank at


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OCSD’s Plant No. 2. The recommended results from this study are summarized in this

Engineer’s Report.

Chapter2–OCSDWastewaterFlowsThe OCSD operates two wastewater treatment plants that collect all of the wastewater from

north and central Orange County for treatment. One facility referred to as the Reclamation

Plant No. 1 (Plant No. 1) is in Fountain Valley and the second facility referred to as Treatment

Plant No. 2 (Plant No. 2) is in Huntington Beach. This section describes the variations in influent

flows to OCSD’s Plant No. 2 and how these flows will affect the GWRS Final Expansion Project.

2.1OCSDTreatmentPlantNo.2–HuntingtonBeachThe OCSD owns and operates Plant No. 2, which is located in Huntington Beach. Plant No. 2 has

the capacity to treat 80 MGD of raw wastewater to secondary effluent. The wastewater comes

into Plant No. 2 through the headworks and primary settling basins. The effluent from the

primary settling basins is distributed to one of two secondary treatment processes. The two

treatment processes are as follows:

(1) Oxygen Activated Sludge (OAS): Uses pure oxygen instead of air to provide metabolic O2

for a conventional activated sludge system for BOD removals. The effluent produced is

of lesser quality as compared to the Plant No. 1 AS1 and AS2 facilities NDN process,

featuring greater suspended solids, ammonia, and organics.

(2) Trickling Filter Solids Contact (TFSC): Similar to P1 TF except with an additional biological

treatment step that increases removals of BOD over conventional TF systems and

provides some additional removal of organics and suspended solids, but overall

produces lesser quality than the Plant No. 1 AS1 and AS2 NDN processes, especially for

ammonia.

For the GWRS Final Expansion Project (GWRSFE), the secondary effluent from the TFSC

treatment facility will be conveyed to GWRS for recycling. The secondary effluent from the OAS

treatment facility will be discharged to OCSD’s ocean outfall pipeline since these flows contain

concentrated brines which are unable to be treated through GWRS by the Regional Water

Quality Control Board permit to operate GWRS.

2.2ProjectedSecondaryEffluentFlowRatesRaw wastewater flows coming into Plant No. 1 and Plant No. 2 varies greatly during the day due

to diurnal flow changes from about (‐)45 percent to (+)30 percent from the average dry

weather flow. The low flow of the day is typically around 6 AM to 7 AM and the peak flow is

typically around 2 PM to 4 PM. The amount of equalization needed is directly affected by the

flow pattern for the plant.


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In early 2015, the average combined flow for Plant Nos. 1 and 2 was about 185 mgd on a typical

day, with about 115 mgd treated at Plant No. 1 and 70 mgd treated at Plant No. 2. This

treatment flow scenario included OCSD operating their Steve Anderson Lift Station (SALS) in

order to maximize flows to OCSD Plant No. 1 for treatment through GWRS.

In the future it is possible that more flow will be treated at Plant No. 2 in order to balance the

influent flows between the two plants. With this in mind, investigation of the potential diurnal

curve was performed to better understand the flow patterns should less wastewater be

diverted from the Plant No. 2 tributary area. Plant personnel indicated that flow quantity and

patterns changed starting in January 2015 due to water conservation. Therefore, a random dry‐

weather weekday flow after January was selected for this analysis (Wednesday April 8, 2015).

Knowing that weekend flows can have different flow patterns, Saturday April 11, 2015 was

analyzed and the differences were not large enough to affect the results of this study.

This flow analysis was done with assumed balanced flows between Plant No. 1 and Plant No. 2

with SALS off‐line.

Figure 3 – Assumed OCSD Plant No. 1 and Plant No. 2 Diurnal Flows (Figure provided by CDM Smith/Brown and Caldwell)


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These volumes represent what is needed to allow the current plant flows to be fully equalized

independently at each plant. In other words, effluent flow from each plant would be constant,

even with the diurnal influent flow swings. GWRS currently has a total of 15 MG of flow storage

available through the two Secondary Effluent Flow Equalization (SEFE) Tanks at Plant No. 1.

According to this analysis, Plant No. 2 would require up to 12 MG of storage for full flow

equalization however, this is too conservative because the volume needed for flow equalization

for both plants is 20 mgd. Therefore, looking at the two plants together, only an additional 5

MGD of flow is truly needed to equalize the combined flow (20 MG combined flow equalization

less 15 MG existing flow equalization capacity at GWRS).

The 58‐inch diameter conveyance pipeline for the stored peak flows from Plant No. 2 will be

connected with the 15 MG SEFE tanks and therefore the combined storage can be used in this

analysis. However it was assumed to add 20% increase in necessary storage for unknowns such

as operational flexibility and refined flow split scenarios between both plants.

Therefore, the need for 5 MG of storage plus 20% equals a total of 6 MG of storage required at

Plant No. 2.

Chapter3‐WaterProductionFlowEnhancementProjectDescriptionDuring the evaluation process as part of the SP‐173 Study – it was determined that an above

ground steel storage tank with the ability to store a minimum of 6 million gallons (MG) of

secondary effluent is the most preferred option to enhance GWRS production through flow

equalization.

The 6 MG storage tank will be located at the north end of the Plant No. 2 property. This location

would tap into the secondary effluent line from the TFSC treatment facility. The treated

wastewater would be pumped into the storage tanks and then drained via gravity during low

flow to enhance water production. This facility would operate very similar to the SEFE tanks as

part of the current GWRS facility. Figure 4 shows the location of the flow equalization tank (i.e.

storage tank) and pump station.


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Figure 4 – Plant No. 2 Flow Equalization Tank and Pump Station Location

The 6 MG storage tank would be connected to the existing 108‐inch secondary effluent pipe

from the TFSC facility by a 48‐inch pipe. There is a proposed pump station which will divert high

flows of secondary effluent within the 108‐inch pipeline to the storage tank typically during the

day. The secondary effluent would then be returned to the 108‐inch‐diameter secondary

effluent pipe during low flows by gravity. This would typically occur at night. Motorized valves

within a vault would allow this configuration to change as needed. The tank would be emptied

every day. The secondary effluent pipe will allow the stored flows to be intercepted by the

Plant No. 2 Secondary Effluent Pump Station which will pump all the Plant No. 2 flows from the


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TFSC facility to GWRS. This pump station is discussed in the GWRS Final Expansion Engineer’s

Report. Figure 5 shows the piping configuration of the tank and pump station.

Figure 5 – Plant No. 2 Flow Equalization Tank and Pump Station Layout

(Figure provided by CDM Smith/Brown and Caldwell)

The flow equalization tank at Plant No. 2 is envisioned as a coated steel tank, above grade, set

on a concrete pad. It would be very similar to the existing SEFE tanks at the GWRS facility. Flow

would enter the tank via the side of the tank, and leave the tank via an outlet on the bottom of

the tank, designed to allow full drainage.

The flow equalization pump station is envisioned as a trench style wet well pumping station

meeting with column type pumps. The diurnal curve for Plant No. 2 indicates a difference of

about 24 mgd between peak flow and average flows, therefore the capacity of this pump

station should be at least 30 mgd to allow for additional flexibility. The pump station will have

three duty pumps and one standby pump. The pumps would be 100 horsepower and a

discharge flow meter would be used to monitor the flows entering the tank. The pump station

will also have an electrical room with two transformers to receive 12 kilovolt power from the

trickling filter electrical system.


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The gravity flow from the EQ tank back to the secondary effluent pipe would be through a pipe

that flows back through the flow diversion box. The pipe diameter would be between 30‐inch

and 48‐inches. A flow meter would be provided to monitor the returning flow. Flow would be

controlled using a flow control valve with a feedback loop from the flow meter.

In order to coordinate the storage capacity at SEFE with the 6 MG storage recommended at

Plant No. 2, the secondary effluent pipe conveying the Plant No. 2 stored effluent will be

connected into the existing 54‐inch‐diameter pipe that currently feeds the GWRS SEFE. This

pipe is also directly tied to the pipe which feeds the secondary effluent to the GWRS screenings

facility. This location is immediately south of Secondary Effluent Junction Box 6 (SEJB6)

at the southeast part of Plant No. 1. This point of connection would allow the Plant No. 2 flow

to augment the Plant No. 1 flow currently at this location. Figure 6 shows the piping connection

to the existing SEFE facility.

Figure 6 – Connection Piping to GWRS SEFE Tanks at OCSD Plant No. 1


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Chapter4–FinancialAnalysisThe costs for the Water Production Flow Enhancement Project will be estimated in this section.

In addition to the estimated capital cost, the O&M costs, and the unit costs for this project will

be compared to imported water costs.

4.1CapitalCostofProjectThe capital costs for the Water Production Flow Enhancement Project will include costs for pre‐

design, design, and construction phases. The total estimated capital cost for this project is

represented in Table 1 below.

Table 1 – Estimated Capital Costs for the Water Production Flow Enhancement Project

Description Cost

Pre‐Design

CEQA $200,000

Design & Consulting Services

Design of Construction Documents $1,700,000

Construction Management $1,000,000

Construction Inspection Services & Administration Costs $600,000

Construction

Mobilization $3,000,000

Steel Storage Tank $7,200,000

Pump Station & Piping $2,800,000

Contractors General Requirements $4,100,000

Total Construction Cost $17,100,000

Engineering, Legal and Administration

Administration Labor $200,000

Public Outreach/Legal Services $500,000

Survey & Outside Consultants $500,000

Contingency $1,600,000

Total Flow Enhancement Project Capital Costs $23,400,000

4.2AnnualOperationandMaintenanceCostsThe estimated annual operational and maintenance costs for the Water Production Flow

Enhancement Project are estimated in Table 2 below.


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Table 2 ‐ Estimated O&M Costs for the Water Production Flow Enhancement Project

Operation & Maintenance Item Estimated Cost

Electricity $80,000

Chemicals $20,000

Labor $100,000

Total Annual O&M $200,000

The electricity costs represent the estimated annual costs to run the pump station. The labor

cost represents an additional full time maintenance employee as part of this project. There is a

small annual chemical cost predicted for the potential sodium hypochlorite addition into the

secondary effluent being stored within the tank. The total annual O&M costs are therefore

estimated to be $200,000.

In addition to these annual costs, OCWD typically predicts a Refurbishment and Replacement

(R&R) cost. These costs represent equipment maintenance and replacement as needed and is

estimated by taking 50% of the estimated construction cost (equipment portion of the

construction project) and diving that by the life of the project (estimated at 30 years). With this

equation the R&R costs are estimated to be $250,000 per year.

4.3PotentialSourcesofFinancingOne potential source of financing this project is the Sate Revolving Fund (SRF) Loan Program.

Currently the state has a program of 30‐year loans at a 1.7% interest rate. This is being offered

on a first‐come, first‐serve basis and staff will be applying for this program for the Water

Production Flow Enhancement Project. However, to be more conservative, the unit cost for the

Water Production Flow Enhancement Project was calculated for two scenarios, 1) with the SRF

Loan Program at 1.7% interest for 30 years, and 2) with typical loan at 5% interest for 30 years.

4.4ProjectedUnitCostofWaterProductionFlowEnhancementProjectWaterThe unit cost of the Water Production Flow Enhancement Project water includes the annual

payment for the capital costs along with the O&M and R&R costs divided by the amount of

extra water produced. The 6 MG storage tanks have the potential to provide an additional 6

MGD of secondary effluent for treatment through GWRS. This converts to 6,700 AFY and is

additional water that would have been otherwise sent to OCSD’s ocean outfall. For the unit cost

calculation, a 10% inefficiency of the use of the storage tanks is being considered since certain

operational constraints may limit how much secondary effluent can be stored. For this reason,

the unit cost will be calculated based on producing an additional 6,000 AFY secondary effluent

for recycling through GWRS.


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Table 3 – Water Production Flow Enhancement Project Unit Cost

Item Cost at 1.7% Cost at 5%

Annual Payment on Capital Cost $1,000,000 $1,500,000

O&M Costs $200,000 $200,000

R&R Costs $250,000 $250,000

Total Annual Project Costs $1,450,000 $1,950,000

Water Produced (AFY) 6,000 6,000

Unit Cost ($/AF) $242 $325

Based on the assumptions listed above, the unit cost for the Water Production Flow

Enhancement Project is between $242/AF to $325/AF. This is water which would still be

required to be treated through GWRS. The GWRS system produced water at a unit cost of

$484/AF for the 2015/2016 fiscal year. With this operational cost added to the unit costs listed

in Table 3 this equates to unit costs between $726/AF and $809/AF.

OCWD policy established in April 2009 calls for comparing the cost of new local water supply

projects against the MWD treated full service rate. To be more conservative, the higher unit

cost of $809/AF for the Water Production Flow Enhancement Project based on a 30‐year loan at

5% interest will be used to compare to MWD imported water rates.

On January 1, 2017, the cost of treated full service MWD water will increase from $942/AF to

$979/AF. There is a ‘readiness to serve’ charge that adds approximately an additional $65/AF

to the total cost of MWD water. This will bring the total treated full service MWD imported

water costs to $1,044/AF.

The Water Production Flow Enhancement Project water is a local water supply project for

groundwater replenishment with a unit cost of $809/AF. Since this product water is pumped

into the ground – to accurately compare the Water Production Flow Enhancement unit cost

with the MWD treated full service rate – an estimated variable cost to pump water out of the

ground must be added to the Flow Enhancement Project costs. This variable cost to pump the

water out of the ground is received from a survey of Cities and Agencies within the OCWD

service area and is currently estimated to be $97/AF. Therefore, the unit cost of the Flow

Enhancement water is $906/AF and less than the MWD treated full service water unit costs.


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Chapter5–ProjectImplementationTo complete the Water Production Flow Enhancement Project, CEQA will need to be

completed, an agreement between OCSD & OCWD will need to be completed, and any

necessary regulatory compliance issues addressed.

5.1CEQAandNEPARequirementsThe CEQA process for the Water Production Flow Enhancement Project will involve completing

a Mitigated Negative Declaration (MND). This MND will address all the impacts predicted as

part of this project. If this project is financed by the State Revolving Fund Loan Program, the

NEPA process will also need to be completed.

5.2InstitutionalAgreementsOCWD and OCSD are currently working on an amendment to a joint agreement between the

two agencies which defines each agencies responsibilities for the Water Production Flow

Enhancement Project. In general it defines the project costs, land leases, and operational

responsibilities for each agency as part of all the joint OCWD and OCSD GWRS Projects.

5.3RegulatoryApprovalsGWRS is currently permitted by the Regional Water Quality Control Board (RWQCB) and

Division of Drinking Water (DDW). The RWQCB/DDW permit contains input and regulations

from California Department of Public Health (CDPH) as well. The DDW was formerly a part of

CDPH as a department/branch of the State Water Resources Control Board (SWRCB). The

current RWQCB/DDW permit will need to be amended to allow for the additional water

received as part of the GWRS Final Expansion Project and the Water Production Flow

Enhancement Project; or a new permit may need to be developed; the latter may be required,

given the changes in RWQCB/DDW regulations since the original GWRS permit was adopted in

2004.

5.4SequencingofProjectActivitiesandScheduleThe schedule for implementing the Water Production Flow Enhancement Project will need to

be closely coordinated with OCSD. The project is being proposed on OCSD’s Plant No. 2

property and will have to tie‐in with OCSD’s utilities and incorporate many OCSD standards in

addition to OCWD’s standards. Additional design coordination time between the two agencies

is factored into the proposed schedule. Also the implementation of the Water Production Flow

Enhancement Project is contingent upon completion of the Plant No. 2 Effluent Pump Station

and Pipeline Project proposed as part of the GWRSFE Project. Therefore, the schedule outlined

in Table 4 incorporates the implementation schedules for the projects required to use the flow

equalization tanks as part of the Water Production Flow Enhancement Project.


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Table 4 – Water Production Flow Enhancement Project Schedule

Description Schedule

Establish Project & Agreements Oct‐16 thru Dec‐16

Design Phase Jan‐17 thru Jun‐18

Construction Phase Jan‐19 thru Jun‐22

Project Implementation/Completion June 2022

5.5FinancialImpacttoOCWDIncorporating the Water Production Flow Enhancement Project will allow OCWD to increase the

amount of AWTF water used for groundwater replenishment to manage the groundwater

basin. In turn, less MWD treated water will be used to replenish the groundwater basin. Since

the Water Production Flow Enhancement Project water unit costs are less than that of MWD

treated water – this will provide an immediate financial benefit to OCWD.

5.6RecommendationIt is recommended to establish the Water Production Flow Enhancement Project detailed

within this report as a feasible and viable project for the Orange County Water District.

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