Pressure Sewer DesignPressure Sewer DesignPressure Sewer DesignPressure Sewer Design

The Key Elements Toward SavingThe Key Elements Toward SavingThe Key Elements Toward Saving The Key Elements Toward Saving Time & Money for Your CustomersTime & Money for Your Customers

Pressure SewerPressure SewerA sanitary sewer system that utilizes a network of grinder pumps to• A sanitary sewer system that utilizes a network of grinder pumps to transport wastewater through small diameter pipes to a collection and treatment system.

• A grinder pump is a submersible pump designed to reduce• A grinder pump is a submersible pump designed to reduce wastewater particulate to a slurry through the use of a grinding mechanism

Wastewater Treatment l Service Connection

LateralPlant

Road

Pressure Sewer Collection System

Figure 1.1 -- Typical lakefront pressure sewer systemTypical lakefront pressure sewer system

Gravity sewers require big equipmentGravity sewers require big equipmentGravity sewers require big equipment, Gravity sewers require big equipment, major excavation and lift stationsmajor excavation and lift stations

Pressure Sewers do not rely onPressure Sewers do not rely onPressure Sewers do not rely on Pressure Sewers do not rely on limitations of gravitylimitations of gravity

• Wastewater is pumped through small diameter pipes following the contour of the land set in shallowcontour of the land, set in shallow trenches just below the frost line

• Lift stations are minimized or eliminated in virtually every installationWaste treatment plants for these• Waste treatment plants for these systems are less costly to build since the system is closed to yinfiltration and solid sizes and minimized.

Infrastructure Development CostsInfrastructure Development CostsInfrastructure Development Costs Infrastructure Development Costs are Lowerare Lower

Major excavation is eliminatedLabor and material costs can be dramatically reduceddramatically reducedEnvironmental disruption anddisruption and restoration are minimized Typical Pipe Size Ranges

Time to complete construction is

d dreduced

Pressure Sewers Provide…Pressure Sewers Provide…An economical solution to geo-technically challenging environmental conditions where gravity sewers may be impractical if not impossibleimpractical if not impossible

Examples include:oRocky soiloHilly terrainoShallow bedrockoShallow bedrock oHigh water tableso Long flat terrainoSlow growth areasoExisting structures/roads

Pressure Sewers: A Proven TechnologyPressure Sewers: A Proven Technology

First used in the early 1970’sProvides daily service to millions of users worldwideDemonstrated excellent performance, high reliability and low Operating and Maintenancereliability and low Operating and Maintenance costs

Typical Residential InstallationTypical Residential Installation

A grinder pump station is located in the yard or basement of each homeWastewater flows into the station from the building’s sewer line (typically 4”)The basin contains a grinder pump levelThe basin contains a grinder pump, level sensors, valves and discharge piping

Typical Residential Grinder Pump Typical Residential Grinder Pump

• A pressure sewer

yp pyp pSite ComponentsSite Components

• A pressure sewer collection line is laid along the edge of the roadway, following the contour offollowing the contour of the land

• The pressure sewer collection line delivers the wastewater to a central treatment system, y ,manhole, or force main

• Wastewater may be transported severaltransported several thousand feet to a discharge point at a higher elevationhigher elevation

Residential Grinder Pump PackageResidential Grinder Pump Package

Basin

Pump Control and/or Alarm Panel

Basin

Piping / Valves

Level Sensors

Grinder Pump

Typical Commercial StationTypical Commercial StationLarger pump station basin for added storage capacityTwo submersible grinder pumps toTwo submersible grinder pumps to provide redundancyThe control panel will include an alarm

d lt t t hand an alternator to run each pump every other cycleNote: Code requirements may be more stringent for

i l i h f id i l icommercial stations than for residential stations.

Operating costsOperating costsOperating costs for a typical residential station can be less than $3.00 per month** Based on 10 cents per Kilowatt Hour and 300* Based on 10 cents per Kilowatt Hour and 300 Gallons per day

Pressure Sewerage Projects A Selection of Design IssuesA Selection of Design Issues

(Keep It Simple, PSS is Different, Not Difficult)

Steve WallacePressure Sewer Solutions Pty Ltd.

swallace@pssolutions.net.auwww.pssolutions.net.au

Ph +61 2 9584 1177Ph +61 2 9584 1177October 2009

Design IntroductionDesign Introduction

Design considerations - ins and outs of design

Performance profile a systems will achieve

Design ConsiderationsDesign ConsiderationsDesign Parameters Development

Masterplan layout development e.g. Existing and ultimate property numbers Future Sewer Areas etcproperty numbers, Future Sewer Areas etc.

Dwelling occupation profile e.g. Vacation houses

Non residential loadings e.g. Commercial properties and point loadspoint loads

Storm allowance (I&I)

Peak instantaneous flows determination methodology, average day peak and after power outage flows. Propertyaverage day peak and after power outage flows. Property discharge rate = 757 l/d/dwelling (~200 gal / day)

Design ConsiderationsDesign ConsiderationsDesign ConsiderationsDesign Considerations

Design Parameters Development (cont)System hydraulic analysis methodology and friction loss factors

Downhill pumping considerations

Ai t (b d d )Air management (buoyancy and odor)

Downstream capacity requirement for systems normal operation and after power outage flowsand after power outage flows

Wastewater flow velocities

Max pump TDH and pump product selection

Design ConsiderationsDesign Considerations

Site Considerations

Environmental, cultural and geotechnical project issues

M i l ti d t t iMain locations and property easement issues

Future mains extensions

Electricity quality - low and high voltage

Design ConsiderationsDesign Considerations

Property ConsiderationsCommunity management plan

Property plumbing & electrical standards and upgrades

Project connection rate e.g. backlog vs. development –long or slow connection period

General trade waste issues e.g. Grease arrestors

Swimming pool backwash

Design ConsiderationsDesign Considerations

Other Issues To ConsiderConstruction Methodologies

Construction Materials Selection

Commissioning Plan

Authorities standards, requirements and charges

Systems operators criteria and service structure should beSystems operators criteria and service structure should be designed into the system

P k Fl C l l ti M th dP k Fl C l l ti M th dPeak Flow Calculation Methods Peak Flow Calculation Methods ((Peak Instantaneous Flows Determination Methodology)Peak Instantaneous Flows Determination Methodology)

35

30

35

Assumptions757L/ET/day

25

RATIONAL METHOD

15

20

Peak

Flo

w (L

/S) RATIONAL METHOD

PROBABILITY METHOD(Instantaneous Peak)

r - FACTOR + No StormAllowance

10

Allowance

CEP = r-FACTOR+50%Storm Allowance

0

5

0 100 200 300 400 500 600 700 800 900 10000 100 200 300 400 500 600 700 800 900 1000ET's

Sewage FlowsSewage FlowsSewage Flows Sewage Flows ((Peak Instantaneous Flows Determination Methodology)Peak Instantaneous Flows Determination Methodology)

35

30

35

Note:ET = 1 House Connection5 l/s = ~80 Gal/ Min10 l/s = ~158 Gal/ Min

25

)

PROBABILITY METHOD(757L/ET/day)

15

20

Peak

Flo

w (L

/S)

Recorded Flows Warneet & Cannons Creek Instantaneous

Design Flows (instantaneous peak)Tooradin, Warneet &

Cannons Creek

10Recorded Flows

Tooradin Instantaneous Peak

Cannons Creek Instantaneous Peak

Tooradin (Recorded 400L/ET/day)

Warneet & Cannons

0

5

0 200 400 600 800 1000

Recorded FlowsTooradin Average of Daily Peak Flows

Recorded FlowsWarneet & Cannons Creek

Average of Daily Peak FlowsRecorded FlowsAlbany Average Daily Peak Flow

Creek (Recorded 400L/ET/day)

0 200 400 600 800 1000

ET's

Pressure Sewer Solutions P/L Pressure Sewer Solutions P/L Peak Flow Calculation Method Peak Flow Calculation Method ((Peak Instantaneous Flows Determination Methodology)Peak Instantaneous Flows Determination Methodology)

Note:400 Litres = ~106 Gal1000 Litres = ~ 264 Gal

Litres//Property/day

Weekly Flow to WWTPWeekly Flow to WWTPWeekly Flow to WWTP Weekly Flow to WWTP (Downstream capacity requirement)(Downstream capacity requirement)

Suburban CommunitySuburban Community 4 l/s = ~63 Gal / Minyy3 Days of Flow3 Days of Flow

PSS Fl t D t 08 10 J l '06 (S t M )PSS Flowmeter Data 08-10 July '06 (Sat-Mon)

6

7

Owen St Jamberoo + Golden Valley Rd Jamberoo 15 sec.

Calculated Peak Flow

5

yOwen St Jamberoo + Golden Valley Rd Jamberoo 5 min.. SmoothedModel Dry Weather Curve (assumed)

Calculated Average Day Peak Flow

3

4

Flow

(L/s

)

2

0

1

12 AM 3 AM 6 AM 9 AM 12 PM 3 PM 6 PM 9 PM 12 AM 3 AM 6 AM 9 AM 12 PM 3 PM 6 PM 9 PM 12 AM 3 AM 6 AM 9 AM 12 PM 3 PM 6 PM 9 PM 12 AM

Vacation Community AVacation Community AVacation Community A Vacation Community A 12 Months of Flow Data12 Months of Flow Data

10 l/s = ~158 Gal / Min

S/O Calculated Peak Flow

PSS Calculated Peak Flow

PSS Calculated Average Peak Flow

Vacation Community BVacation Community BVacation Community B Vacation Community B 2 Months of Flow2 Months of Flow

5 l/s = ~79 Gal / Min5 l/s = ~79 Gal / Min

Calculated Peak Flow

Calculated Average Peak Flow

General Trade Waste IssuesGeneral Trade Waste Issues

Food Shop - Wastewater pre treatment must be assessed.This existing food shop grease arrestor is too small therefore inadequate treatment for connection to any sewerage systeminadequate treatment for connection to any sewerage system and will shorten the life of your pump unit if connected.

Inflow and InfiltrationInflow and Infiltration

Does it happen in a pressure sewer system?

How is it managed and eliminated?

Wet Flow Wet Flow –– Does It Happen?Does It Happen?

THURSDAYS WET WEATHER INSTANTANEOUS FLOWSTOORADIN JUNE 2003 - JUNE 2004(DRY WEATHER - MAX, MIN, AVE)

4 5

3.5

4

4.5Design

Instantaneous Peak Sewage Flow for

235 property connections= 6.96L/S

4 l/s = ~64 Gal / Min

2.5

3

W (L

/S) Maximum

RecordedADWF = 1.29L/s

1.5

2

FLO

W Average

Minimum

31 July 2003(8mm)

14 A 2003

2 l/s = ~32 Gal / Min

0

0.5

1 14 Aug 2003(5mm)

12 Feb 2004(9mm)

10-Jun-04(14mm)

0 3 6 9 12 15 18 21 0

TIME

Wet Weather FlowWet Weather FlowPSS Flowmeter Data 21-25 July '06 (Fri-Tues) with Rainfall

5

6

20

24Golden Valley Rd Jamberoo 890011 15 sec.890011 15min. (smoothed)Rain Kiama5 l/s = ~79 Gal / Min

4

5

s)

16

20

all (

mm

)

2

3

Flow

(L/s

8

12

Cum

ulat

ive

Rai

nfa

1 4

C

021/7 12 AM 21/7 12 PM 22/7 12 AM 22/7 12 PM 23/7 12 AM 23/7 12 PM 24/7 12 AM 24/7 12 PM 25/7 12 AM 25/7 12 PM 26/7 12 AM

0

“Rainfall events graph indicates no noticeable increase in flows during rainfall. A check of the d t t f i t ti h d th t th l i f ll t d i th l t h lfdownstream transfer sewage pumping station showed that other larger rainfall events during the last half of 2007 did not show any noticeable wet weather flows” — 16/4/07 A. Bovis, Sydney Water Corporation.

Wet Flow Wet Flow –– Does It Happen?Does It Happen?

Litres

250000

Hea

vy R

ain STP INFLOW VOLUME

200000

H 21,000 L = ~5,547 Gal

100000

150000

Litres

Wet

Day

Rai

n

Wet

Day

50000

7,000 L = ~1,850 Gal

0

6/02/2

007

7/02/2

007

8/02/2

007

9/02/2

007

10/02

/2007

11/02

/2007

12/02

/2007

13/02

/2007

14/02

/2007

15/02

/2007

6 7 8 9 10 11 12 13 14 15

After Power Outage FlowsAfter Power Outage Flows

What does it mean to a systems design and operation?

After Power Outage FlowsAfter Power Outage Flows

18 l/s = ~285 Gal / Min

4 l/s = ~63 Gal / min

After Power Outage After Power Outage FlowsFlows

Air ManagementAir Management

• What is it?

• Buoyancy Head

• Moving and expelling air within the system

M i Ai I PiM i Ai I PiMoving Air In Pipes Moving Air In Pipes ((Downhill Pumping Considerations)Downhill Pumping Considerations)

0.6 M/s = ~ 2’ / sec

Referenced From Wallingford Institute Air in Pipes Study

OdorOdor & Corrosion Issues and Control& Corrosion Issues and Control

Odor needs to be considered in the following context.• Whilst sewerage is under pressure in the main odor will• Whilst sewerage is under pressure in the main odor will

not be released.

• When the pressure line is discharged to the atmosphere (liquid and gas phase) hydrogen sulphide may be released.

• May be odorous and corrosive to system components.

OdorOdor & Corrosion Issues and Control& Corrosion Issues and Control

• Methods of odor management involve the following:

Design system with short wastewater retention time in pipep pDischarge wastewater to location where odor wont be detectedChemical dosing into the wastewater flowChemical dosing into the wastewater flowScrubbing the gas phase release or high level ventFlushing water into the mainSelection of non-corrosive materials and protecting other surface structures

Odor Control FacilityOdor Control Facility

Odor Control FacilityOdor Control Facility

Air ScrubberAir Scrubber

ConclusionConclusion

Consider issues such as:

• Peak wastewater flow calculation methods and• Peak wastewater flow calculation methods and understand where the systems performance boundaries are.

• Type of projects e.g. urban residential, vacation community etc.

• Storm allowance (I & I)

• After power outage flows

• Air management

◦ Trade waste treatment

Steve WallacePressure Sewer Solutions Pty Ltd.

swallace@pssolutions.net.auwww.pssolutions.net.au

Ph +61 2 9584 1177Ph +61 2 9584 1177

Walt ErndtEnvironment One Corporation

werndt@eone.comwww.eone.com

Ph 518.346.6161