singapore’s experience of water loss...
TRANSCRIPT
Lai Kah CheongChief Engineer
Singapore’s Experience of Water Loss Reduction
7 Sep 17
www.pub.gov.sg
Annual rainfall 2,400 mm
Average water
demand
1.95 million m3/d (430 mgd)
55% Non-Domestic
45% Domestic
Singapore,
718 km2
Population, 5.6m
~34km
~53km
Biodata of Singapore
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The Water Loop
From sourcing, collection, purification and supply of drinking water, to treatment of used water and turning it into NEWater, drainage of storm water
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Sustainable Water Management
Four National Taps
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Our Water Supply System
From Waterworks to Customers’ Taps
• Highly integratednetwork dispatchingtreated water fromvarious sources
• Ring main system toprovide alternatefeed
5,500 km Portable Water (PW) pipelines
605 km NEWater (NW) pipelines
39 km Industrial Water (IW) pipelines
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5
Replacement programme of unlined CI mains and GI
connections
Replacement programme of leak prone mains and AC / CI mains
Effect of Replacement Programme: Lower UFW
Singapore’s Unaccounted-for-Water (UFW)
10.6
5.0
0.0
2.0
4.0
6.0
8.0
10.0
12.0U
FW
%
Unaccounted-For Water
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Our UFW Management Framework
Network Management1. Use good quality / corrosion-resistant material
2. Strict supervision & control on workmanship
3. Regular servicing and replacement
Accurate Metering
1. 100% metering
2. Use of compound meters to capture both low flows and high flows
Active Leakage Control1. Annual leak detection programme
2. Use of smart sensors in the network
3. Pursuing trials actively with a view to adopt (e.g. permanent monitoring of large water mains, Satellite imaging leak detection)
Strict LegislationStrict Enforcement on water theft
Penalties: $50,000 fine or; 3 years
jail term or; both fine & jail term
Low UFW
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Key Challenges Ahead
Challenges
Growing Asset Base & Ageing Infrastructure
Urban Congestion
Growing population and
economy
Complex Network and Open Zones
• Difficulties in Leaksurveillance and inSetting up of DMAzones
• Rising Water Demand• Reduce water loss for
efficient and sustainablewater supply
• Maintaining expandingand ageing infrastructurefor low UFW andefficient supply
• Complex Design andconstruction
• More costly method oflaying pipes (e.g. pipejacking or tunneling)
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Network Life Cycle Management
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Design and Construction
Continuous monitoring
Predictive Maintenance
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Design and Construction9
Localised Corrosion Monitoring with CMAS • Use of Coupled Multi-electrode Array Sensor (CMAS) for measurement of localised corrosion
• Quick and easy to obtain results (5mins) vs traditional soil tests (6 weeks)
• Helps to determine if increased protection necessary at the pipe laying stage
Some locations with CMAS results
Based on 5 mm thicknessAsset lifespan : 70 years
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Principle of CMAS Probes for Corrosion Monitoring
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Design and Construction
Surrounding soil
• Check Corrosiveness –CMAS/Soil Testing
• Recognize the conditions – e.g. high water table
PipeMove towards pipes with PU Coating
Additional Protection
• Use of bedding - quarry dust in normal circumstances
• Cathodic protection to minimise corrosion
• Additional wrapping for exposed pipes and pipes in common services tunnel
QC
• Record baseline condition for new pipelines
• Conduct CCTV inspection for internal defects
• Inspect for external defects – Eg. Check coating is intact using Direct Current Voltage Gradient (DCVG) analysis
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Strict new regulations for inspection and monitoring of new construction along the pipe corridor
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320 sensorsdeployed island-wide to monitor in
real-time the pressure, flow and quality of water in our network
ENHANCE OPERATIONS
• Early detection of leaks, pipe burstand water quality incidents
• Improve response time
• Minimise impact to customers
• 120 sensors on 100km of criticaltransmission mains for leak detection
• Install more sensors to improve thecoverage of PW network, and to also coverNW and IW networks in the next 3 years.
Moving Forward
• Smart Water Grid
Continuous Monitoring of the Network
• New Regulations
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• AMR – Automated Meter Reading
• AMR and boundary flow meters - identify the area of potential leaks at the macro level through “Virtual DMA”
• Virtual DMA – retaining supply reliability while achieving leak detection
Continuous Monitoring of the Network
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Framework of Pipeline Condition Assessment
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1) Desktop asset management, data analytics,
2) Field, Non-Invasive Survey Methods
3) Field, Invasive Survey Methods
4) Field, Intrusive,
Destructive Test
• Analyse asset characteristics based on age/ material/ location/ failure history
• Pipe wall thickness measurement, coating defect survey, leak detection
• RFT pipeline condition assessment, in-line CCTV
• Coupon sampling and lab testing; section cut outs and lab testing
Replace Rehabilitate Defer Monitor Repair
Predictive Maintenance
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Risk-Based Study to Prioritise Pipelines for Renewal
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• Ongoing pilot study by Arcadis for ~700km of cast iron pipelines.
• Considers both likelihood of failure and consequence of failure to prioritise pipelines for renewal.
• Extend similar analysis to facilitate prioritisation of renewal for the rest of the network from 2018 onwards.
Preliminary Results for 700km of CI pipelines
Predictive Maintenance
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Non-invasive Methods
“ePulse” Uses acoustics sensors to induce sound waves to measure average wall thickness over intervals.
• Will embark on pilot condition assessment of 7.5km of aged large diameter Cast Iron water mains in City area in 2017.
• We plan to implement regular condition assessment on our watermains in the long-term.
“P-Cat” Uses pressure transients to determine thethickness of various sections of pipeline.
Develop Capabilities – Pipeline Condition Assessment
“ DCVG & CIPS “Direct Current Voltage Gradient (DCVG) & Close Interval Potential Survey (CIPS) to detect protective coating defects
“Wilson Taylor” “Echologics”
Predictive Maintenance
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Functions include: • In-line Leak
detection• CCTV
Invasive Methods
“SAHARA
Develop Capabilities – Pipeline Condition Assessment
“MTA Pipe Inspector”Cable-Less Video inspection with Integrated Leak Detection
“Smart Ball”In-line Leak detection
“ PICA “(SeaSnake Remote Field Technology)
“ Pipe Diver “
Electro-magnetic method; Detect defects through the pipe length and around the circumference.
“ Submersible CCTV or ROV“
Visual inspection of internal
condition of pipe.
Predictive Maintenance
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Non-conventional renewal method: Pipe-bursting
Learning from Hong Kong on their watermain rehabilitation experience:• Carry out open-cut replacement of
pipelines where possible; pipe rehabilitation is mainly carried out for straight length of pipe.
• Not preferred for distribution mains with many off-takes.
Rehab Method using PE-Lined pipes
• Increasing underground space constraints, especially for replacement of large diameter trunk mains.
• Pipejacking and Tunnelling
• carry out water main rehabilitation trials.
Congestion of underground services
Develop Capabilities – Trenchless Pipe Renewal Methods
Predictive Maintenance
Thank you…