Performance-based Leakage Reduction and Management Services SAWACO Zone 1 Training and Transfer of Technology

Performance-based Leakage Reduction and Management Services

SAWACO Zone 1Training and Transfer of Technology

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Outline

Classroom Training Modules

Field Training Modules

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Outline

Classroom Training Modules

Module 1 DMA Design

Module 2 DMA Construction and Commissioning

Module 3 Active Leakage Control

Module 4 Pressure Management

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Classroom Training Module 1DMA Design

Definition of District Metering Area (DMA) is a world-wide accepted tool to operate and manage a

network area wherein hydraulic boundary is defined by a system of Isolation Valves (IV) an flow Meters

a discrete area of a water distribution network. It is usually created by closing boundary valves so that it remains flexible to changing demands. However, a DMA can also be created by permanently disconnecting pipes to neighboring areas. Water flowing into and out of the DMA is metered and flows are periodically analyzed in order to monitor the level of leakage

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Definition of District Metering Area (DMA)has water service connections ranging from 500-3,000can be categorized into the following types:

Single inlet DMAs Multiple inlet DMAs Cascading DMAs

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General Guidelines in DMA DesignDMAs should not include trunk mains or storage tanksEach DMA should preferably be supplied through a single,

metered supply pointDMA boundaries should be created by closing boundary

valvesVariations in ground elevation should be minimal across the

DMAThe types of consumers and their respective water supply

requirements should be assessed

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General Guidelines in DMA DesignLegal regulations governing minimum pressures, local

constraints due to topography and height of buildings as well as fire fighting requirements have to be respected

Closing boundary valves to create DMAs will increase the number of dead-end pipes

Pressure management plays a key role in leakage management

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Planning, Design and Engineering

Planning and

PrioritizationField Survey Preliminary

DesignHydraulic Simulation Draft Report Final report

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Planning and Prioritization

• Preliminary design by Manila Water design team in coordination with

MWH network modelling team

• Prioritization by highest leakage potential

• Manila Water prioritization was initially based on the following:• Pipe material• Pipe age• Number of leak occurrences

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Field Survey

• Data gathered during site investigation:• Location and status of existing valves, fire hydrants and blow-offs.• Big consumption customers• Pressure• Road classification• Traffic

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Preliminary Design

• Preliminary design of 119 DMAs in the Feasibility Study done in 2005

• One line meter per DMA with a range of 1000-2000 service connections

• DMAs per District• District 1 – 24 DMAs• District 3 – 29 DMAs• District 5 – 28 DMAs• District 10 – 38 DMAs

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Hydraulic Modelling

• MWH conducted the hydraulic simulation based on the initial design submitted by MWC

• The term hydraulic network model describes the use of a mathematical representation of a real water supply system

• Hydraulic network models are used to simulate the behavior of existing or planned systems under a wide range of conditions without disrupting service to the customer

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Draft Report

• The preliminary DMA design report is based on Decree 209/2004 (Quality Managements of Construction Works) which contains the following:• DMA Description• DMA Information• Quantity of work• Applicable Standards• DMA Design• Drawings• Work Schedule• Work Methodology• Site Regulation and Safety

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Final Report

• Approval of the preliminary report is sought in order to produce the 10

copies of final report

• Combination of DMAs are done in order to pass the requirements of the

hydraulic simulation and other design criteria

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Classroom Training Module 2DMA Construction and Commissioning

Permit Acquisition Civil Works Commissioning

Works

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Permit Acquisition

• Preparation of Drawings with underground obstructions

• Process of Issuance of UTM Agreement

• Submission of DOT Agreement

• Submission of DOT Permit

• Issuance of Permit

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Classroom Training Module 2DMA Construction and Commissioning Permit Acquisition

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Civil Works

• Line Meter Assemblies

• Isolation Valves

• Looping and Interconnection Activities

• Pipelaying Activities

• Fire Hydrants

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Classroom Training Module 2DMA Construction and Commissioning Civil Works

Line Meter Assembly Electromagnetic Flow Meter Pressure Reducing Valve Strainer By Pass Connection Panel Box

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Commissioning Works

• Water Adequacy Test

• Zero Pressure Test

• Baseline Measurement

• Baseline Report

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Classroom Training Module 2DMA Construction and Commissioning Water Adequacy Test

Water Adequacy Test will be conducted to ensure sufficiency of water

supply within the isolated DMA despite of having only a single supply point

WAT starts with the measurement of pressure at benchmark points within

and outside of the DMA prior to and after closure of all isolation valves

It is important that during the conduct of Water Adequacy Tests (WAT), all

service connections covered by a particular DMA is identified, verified and

tagged

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Classroom Training Module 2DMA Construction and Commissioning Water Adequacy Test Steps

1. Identify all boundary valves.

2. Determine if the valves are operable, if not, replace the boundary valve.

3. Monitor the pressure before and after isolation inside and outside the DMA

4. Before closing any valve, install pressure gage in the hydrant inside the

DMA

5. Close the boundary valve one by one

6. Continue closing all boundary valves

7. Compare the pressure before and after the isolation

8. If there is a big pressure drop, the DMA needs to be redesigned or

introduce and additional supply usually by opening the critical boundary

valve

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Check Pressure w/in & outside DMA

– Close all Isolation Valves– Let water pass thru District Meter (inflow &outflow).

– If water is adequate within & outside the DMA, let all Isolation Valves be remained closed as supply will now pass through the District Meter.

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Classroom Training Module 2DMA Construction and Commissioning Zero Pressure Test

ZPT is conducted following the Water Adequacy Test to ensure the

tightness of isolations

In principle, once all the isolation valves are closed including the

inflow/s, pressure inside the DMA should drop to zero until no water

comes out of the monitoring point/s

The test is normally done during off-peak hours (1AM to 4AM),

when demand is at its lowest and pressure is theoretically at its

peak

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Classroom Training Module 2DMA Construction and Commissioning Zero Pressure Test Steps

1. Inform the customers about the schedule of the water interruption.

2. Identify critical point, usually the hydrant in the lowest elevation of the DMA.

3. Closed all the supply points

4. Open the hydrant to check if there will be no water (preferably the hydrant in the lowest elevation

inside the DMA).

5. If there is still water after several minutes, check all the boundary valves if they are tightly closed.

6. If all the boundary valves are fully closed and still there is water in the monitoring point, then there

is unknown inflow inside the DMA.

7. Check where the pressure is the highest as the unknown inflow may be in that area.

8. Check old maps for old lines.

9. Use GPR, pipe locator and other equipment to find old lines.

10. Conduct step testing to localize the location of unknown lines.

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Supply

-Leaks (Physical Loss)

-Identified Night Users

Supply= Allowable Night Flow + Physical + Identified Night Users

Physical Losses= Supply- Allowable Night Flow -Identified Night Users

- Unidentified night users

(0.06lpm/wm)

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Classroom Training Module 2DMA Construction and Commissioning Baseline Measurement

If Water Adequacy and Zero Pressure Test are successful, the next

step is to conduct the baseline measurement

Baseline Measurement is done to determine the baseline NRW of a

particular DMA

Baseline measurement is usually done on the period of 7 days to

capture one complete cycle of water consumption pattern in the

DMA

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Classroom Training Module 2DMA Construction and Commissioning Baseline Measurement Steps

1. Identify all the water service connection inside the DMA based on the design

boundary.

2. Identify and replace all defective water meters before baseline measurement to

increase the accuracy of data.

3. Carry out the baseline measurement. Read all DMA meters (inflow and outflow) on

the 1st and 7th day, ideally at the same time. Compute Qi in m3/day.

4. Read all customer meters on day 1 and 7 of the measurement. First and second

reading of a specific meter should be at approximately the same hour of the day.

5. Calculate the total metered consumption of all customers in the DMA by utilizing the

90 day billing average from SAWACO or JSC and calculate the daily average QM

(m3/d).

6. Calculate baseline leakage

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Classroom Training Module 2DMA Construction and Commissioning Baseline Measurement Formula

Lb = Qi – Qm

Where

Lb = Leakage during baseline in m3/day

Qi = DMA inflow in m3/day

Qm = metered consumption (billed volume) in m3/day

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Classroom Training Module 2DMA Construction and Commissioning Data Logging and Data Transfer

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Classroom Training Module 3Active Leakage Control

Analysis and Control

Leak location/detection Leak repair Monitoring and

Measurement

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Speed/

Quality of Repairs

Active

Leakage

Control

Water Losses due to Leakage

Four Pillars of Physical Loss Management

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Analysis and Control

• A proactive strategy to reduce water loss through detection of

nonvisible leaks

• Involves the regular survey of the water network using one or

more techniques in detecting leaks in water mains

• Performing night flow measurements on a regular basis to detect

new leaks as soon as possible

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Leak location /detection

• Leak Detection or localizing by means of a step test or acoustic logging survey enables the leakage engineer to narrow down the location of the leak or burst to an individual road or length of main

• Next activity for the leakage engineer is to precisely locate or pinpoint the position of the leak and mark the point clearly on the ground surface where the repair teams will have to excavate

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Step Testing Step testing is the technique whereby a leak or leaks are detected

by making temporary successive valve closures to reduce the size

of a DMAThe valves are closed for a short duration whilst

simultaneously measurements of the rate of flow are being made

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Step Testing Procedure Survey and check the operability of all the existing valves inside the DMA.

Plan the sequence of step test segment carefully utilizing the information

gather from the valve survey.

Schedule the activity during minimum demand usually 12:00 – 4:00 am.

Inform the customers in advance regarding the Step test activity.

Start closing the valves from the segment farthest from the line meter.

Record valve details (location and no. of turns) and time of closure;

Read the transmitter (totalizer and instantaneous flow) after every valve

closure or set data logging every minute for more comprehensive data.

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Step Testing Procedure Continue the step test until all segment are completed, the last segment

being the area supplied by the line meter. If possible, check if there is no

water in each segment.

Open the valves slowly in reverse order.

Do flushing activity to avoid dirty water complaint.

Analyze the step test data to determine the segment with the highest

possible leakage.

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Step Testing

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• Close Step-Test Valves @ 15min interval

• Open Step-Test Valves @ 15min interval (REVERSE OPERATION)

Upload Mtr (if Logger Ready)

If DM has no Data Logger, read mtr. @ 5 min. interval

This is done 15min before the 1st STV is closed up to the last STV is re-opened.

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1145 lpm

795 lpm

195 lpm

100WSC

500WSC

150WSC

195 lpm

600 lpm

350 lpm

Highest physical loss


Step Testing

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Equipment

Leak Noise Loggers

Ground Microphone

Leak Noise Correlators

GPR

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Leaks commonly occur on:Service Connection

Service pipe Tapping House meter assembly

Mainline Main pipe Joints

Valve

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Classroom Training Module 4Pressure Management

Definition of Pressure Management

the practice of managing system pressures to the optimum

levels of service ensuring sufficient and efficient supply to

legitimate uses and consumers, while reducing unnecessary

excess pressures, eliminating transients and faulty level

controls all of which cause the distribution system to leak

unnecessarily

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Zone 1 Experience

the overall aim is to ensure that the pressure during the day

is not significantly lower that the pressure at night. To keep

the pressure within optimal levels inside the DMA, PRVs

previously installed with the rest of the flow meter set

assembly will be operated

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Pressure Reducing Valve (PRV)

maintains the optimum pressure in

the network at all times, but

automatically compensates for the

reduced flow following the repair of

the leaks whilst maintaining the

original operating pressures in the

DMA

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Pressure Management and Modulation

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Pressure Management and Modulation

Modulation Location

Local point pressure modulation

Critical point pressure modulation

Modulation Type

Fixed outlet pressure modulation

Time-based pressure modulation

Flow-based pressure modulation

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Outline

Field Training Modules Water Adequacy TestZero Pressure TestStep-TestingUse of leak noise correlatorUse of leak pen in leak detectionUse of ground microphone for leak detectionLine meter and PRV operationPMAC Familiarization/ Data Center

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Documents

Performance-based Leakage Reduction and Management Services SAWACO Zone 1 Training and Transfer of Technology