Potential of Water and Energy Savings in Bangkok Water Supply System, Thailand

M. S. Babel and K. AnusartAsian Institute of Technology, Thailand

msbabel@ait.asia

ATHENS 20175th International Conference on Sustainable Solid Waste Management

21-24 June 2017

• Introduction• Study Area• Methodology• Analysis, Results and Discussion• Conclusions• Recommendations

Contents2

Background

Water-Energy Nexus

Source

Conveyance

Treatment

Distribution

End-user

Water Supply System

Water for Energy

Energy for Water

Extraction & Refining Hydropower

Thermo electricCooling

Fuel Production(Ethanol, hydrogen)

WastewaterTreatment

Drinking WaterTreatment

Extraction and Transmission

Energy Associatedwith Uses of Water

3

• To evaluate the energy consumption in Bangkokwater supply system

• To estimate energy consumption by end-users (customers) in a selected pilot area

• To evaluate various alternatives to conserve water and energy consumption in the selected pilot area

Objectives of the Study

Objectives4

Study Area

Metropolitan Waterworks Authority (MWA)

• Service area 2,400 km2

• 16 branches• 913 DMAs • 8 million population served• 4.76 MCM per day

5

Study Area (Pilot area)

DMA 15-03-02

• Area 0.76 km2

• 1,310 connections• Avg. pr. 9.94 m• Water loss 34.27%

Supply Process

Treatment Plant: Bangkhen

Water Treatment Plant

Pumping Station: Prachanukul

Pumping Station

Service area: DMA 15-03-02

MWA

Prachachuan Branch

DMA 15-03-02

DMA

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7 Methodology

Bang KhenSamsenThonburiMahasawat

Raw Water CanalRaw Water Pipe

Tunnel

Phetchakasem

Lat Praow

Phrachanukul

Phahonyothin

Ratchaburana

Tha Pra

Bang Pli

Min Buri

Lat Krabang

Bang Khen 04Bang Khen 03

Klong Toey

Sam Rong

Lumpini

Mahasawat

Bang Len Samlae

MWA Water Supply System

Bang Sue

Tunnel

Raw Water CanalRaw Water Canal

Raw Water Intake

Water Treatment Plant

Water Distribution

Chao Phraya River

Mae KlongRiver

8

MWA Water Production

Average Water Volume in Each Stage of MWA

Remark: Fiscal Year 2004 (Oct 2003-Sep 2004)

MWA Water Supply StageAverage (Fiscal Year 2004-2011)

Volume (106 m3) % Proportion Per capita (L/day)

Raw Water Intake 1,894.4 100.0 659.7

Losses in Raw Water Canal 137.6 7.3 47.9Water Treatment 1,756.8 92.7 611.8Losses in Treatment Process 61.9 3.2 21.5Water Distribution 1,694.9 89.5 590.3

Water Production 1,694.9 89.5 590.3

NRW 486.3 25.7 169.5

Water Sales 1,208.6 63.8 420.8

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MWA

Water Production and Energy Use in Each Stage of MWA

10

MWA Energy Consumption

Energy Consumption in Each Stage of MWA

Average (2004-2011)Raw Water

IntakeWater

TreatmentWater

TransmissionWater

DistributionTotal

Energy Use (kWh/m3) 0.0097 0.0469 0.0961 0.0811 0.2338

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Sources of Data- Field survey- MWA (water bills)

Household CharacteristicsRespondent Category

Category Description Respondent %

M1 Residence 127 58.8

M2Company, ShopCondominium (Bulk)Residence (Bulk)

79 36.6

M4 Restaurant 2 0.9

M5 Institution 4 1.9

M6 School 2 0.9

M7 Construction 2 0.9

Total 216 100

Household

Tank

Pump

Household Survey

DMA 15-03-02

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Characteristic Range Average MostNo. of people per connection(person) 1 - 600 29 ≤3 51% M1, M2

Building storey(floor) 1 - 10 3 2 44% M1, M2, M6

Water bill(baht)

91 - 49,176 1,219 ≤500 70% M1, M2, M4,M7

Tank capacity(litre) 300 - 32,000 2,725 ≤1,000 39% M1, M2, M6

Pump capacity(watt)

150 - 18,730 856 >200 – 400 44% M1, M2, M3

Pump cost(baht) 3,500 - 80,000 7,842 ≤5,000 53% M1, M2, M4,

M6

Pump life(year) 1 – 21 9 >4 - 8 45% M1, M2, M4,

M6

Maintenance - Pump life(year) 3 – 15 8 10 44% M1, M2

Maintenance - cost(baht)

100 – 5,000 1,263 500 30% M1, M2

Household Survey

Household Characteristics (216 sample)

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Household Water Distribution System

Distribution system Range Average Most % Proportion

Type A (floor) 1 - 6 2 2 53 % M2 20.8

Type B(floor) 1 - 4 2 2 60 % M1, M2, M6 54.2

Type C(floor) 3 - 6 4 4 76 % M1, M2, M4,

M5 21.3

Type D(floor) 8 - 10 9 9 50 % M2 3.7

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Household Characteristics by Customer Type

Energy Consumption in Household15

Characteristic

Type of customer (216)

M1(127)

M2(79)

M4(2)

M5(4)

M6(2)

M7(2)

Persons per connection (no.) 3 3 6-10 50-100 50-100 10-20

Building Storey (no. of floor) 1-8 1-9 4 3-10 2-4 1

Avg. Building Height(m) 7 11 12 17 9 3

Pump Capacity (watt) 200-400 200 200-400 5,000-10,000 200 -

Total Pumping Duration (h) 381 371 12 28 8 -

Total Water Sales (m3/month) 5,499 15,045 136 8,311 241 33

Avg. Water Sales (m3/month) 43.3 190.4 67.8 2,077.7 120.4 16.5

Household Energy Consumption in Study Area

Remark:

Energy Use in Household

Average Household Energy Consumption (kWh/m3)

Type of Customer

M1 M2 M4 M5 M6 Average

Case 1 0.53 0.45 0.11 1.00 0.19 0.50

Case 2 0.28 0.27 0.11 0.66 0.10 0.28

Case 3 0.40 0.36 0.11 0.83 0.15 0.39

Case 4 0.66 0.54 0.11 1.17 0.24 0.61

Case 1: Energy use based on no. of pumping hours from field surveyCase 2: 50% of case 1Case 3: 75% of case 1Case 4: 125% of case 1

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Energy Consumption

Energy Consumption for Raw Water to Tap Water

Process Energy Use (kWh/m3)

Utility Raw Water Intake 0.006726%Water Treatment 0.0486

Water Distribution 0.1213Customer End-User (Pump) 0.5000 74%Total 0.6765 100%

Case Study: DMA 15-03-02

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Case% Proportional Energy Use

MWA Customer 1 26 742 39 613 31 694 22 78

Case 1: Energy use based on no. of pumping hours from field surveyCase 2: 50% of case 1Case 3: 75% of case 1Case 4: 125% of case 1

Development of Network ModelInformation for Modeling Description

Pipe Length km 25.21No. of Pipes No. 316Pipe Diameters mm 25, 50, 100, 150, 200, 300Pipe Materials - AC, DI, GI, PB, PVC, STInstallation Year year 1967-2012Valve - FCVMetered Connection no. 1,310No. of Inlet point 1No. of Outlet point 0

Type of Customer Avg. Base Demand (m3/day)

M1 Residence 1.03

M2Residence and Condominium (Bulk), Company, Shop

3.77

M4 Nightclub, Restaurant 2.23M5 Institution, Official Place 80.91M6 School 11.29M7 Construction 2.38

Water Distribution Network Modeling

• Basic Information• Base Demand

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Development of Network Model

Water Distribution Network Modeling

• Demand Pattern

M1

M2

M4 M7

M6

M5

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Field Measurement

• 4 Mobile Pressure Sensors (MPS)

Field Measurements for the Calibration

MPS No.Pressure (m)

Minimum Maximum Average01-18 7.42 10.94 9.67 01-25 7.50 11.06 9.60 03-45 7.49 10.75 9.62 03-64 7.52 10.64 9.55

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Model Calibration

Calibrated ParameterPipe Material Pipe Age (Year) Pipe Roughness CoefficientAC 23-38 100-110

DI 2 130

GI 8-38 90-115

PB 12-38 110-135

PVC 1-26 110-145

ST 7-38 110-140

Area Average Pipe Age (Year) Emitter CoefficientMPS 01-18 18.6 0.14

MPS 01-25 15.6 0.11

MPS 03-45 13.6 0.09

MPS 03-64 18.8 0.14

Head Loss Formula: Hazen-Williams, hL = AqB

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Model Calibration

• Inflow to the system (DMA 15-03-02)

Comparison of Observed data and Simulated Results

Remark: Data obtained 21-31 July 2012

22

Model Calibration

• Pressure at 4 Sampling Locations (MPS Installations)

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Remark: Data obtained 21-31 July 2012

Model Verification

• Flow at DMA Inlet

24

Model Verification

• Pressure at DMA Inlet

25

Alternative Description

A0 Base case Minimum service pressure of 7.5m with 100% base demand

A1 Pressure management (Decreasing Service Pressure)

Minimum service pressure decreased to 3, 5, 6 and 7m with 100% base demand

A2 Demand management(Decreasing Base Demand)

Base demand decreased to 80 and 90% with minimum service pressure of 5, 6, 7 and 7.5 m

A3 Energy Generation(Decreasing Service Pressurewith Turbine generator)

Hydro turbine generator used to generate energy with minimum service pressure of 5, 6 and 7m and with 80, 90 and 100% base demand

A4 Pressure management (Increasing Service Pressure)

Minimum service pressure increased to 9, 12, 15, 18 and 21m with 100% base demand

A5 Pressure management (Increasing Service Pressure with PRV)

PRV used to fix the minimum service pressure of 12, 15, 18 and 21m with 100% base demand

Alternatives26

Alternative 1

Alternatives DescriptionA0 Base case Minimum service pressure of 7.5m with 100%

base demand

A1 Pressure management (Decreasing Service Pressure)

Minimum service pressure decreased to 3, 5, 6 and 7m with 100% base demand

Alternative 1

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Alternative 128

Alternative 1

Alternative 2

Alternatives DescriptionA0 Base case Minimum service pressure of 7.5m with 100% base

demand

A2 Demand management(Decreasing Base Demand)

Base demand decreased to 80 and 90% with minimum service pressure of 5, 6, 7 and 7.5 m

29

Alternative 2

Alternative 230

Alternative 2

Alternative 3

Alternatives DescriptionA0 Base case Minimum service pressure 7of .5m with 100%

base demandA3 Energy Generation

(Decreasing Service Pressurewith Turbine generator)

Hydro turbine generator used to generate energy with minimum service pressure of 5, 6 and 7m and with 80, 90 and 100% base demand

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Alternative 3

Alternative 332

Alternative 3

Alternative 3

Remark: *Pressure - Minimum Service Pressure at Critical Point

Energy GeneratedSub-Alternatives *Pressure (m) Base Demand (%) Energy Generated (kWh/day)

A3.1 5 100 48A3.2 6 100 54A3.3 7 100 64A3.4 5 90 43A3.5 6 90 49A3.6 7 90 59A3.7 5 80 39A3.8 6 80 43A3.9 7 80 54

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Alternative 4 and 5

Alternatives DescriptionA0 Base case Minimum service pressure of 7.5m with 100% base

demandA4 Pressure management

(Increasing Service Pressure)Minimum service pressure increased to 9, 12, 15, 18 and 21m with 100% base demand

A5 Pressure management (Increasing Service Pressure with PRV)

PRV used to fix the minimum service pressure of 12, 15, 18 and 21m with 100% base demand

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Alternative 4 and 5

Alternative 4 and 5

*Pressure (m)

Floor (s)% Water Consumption

with Pump% No. of Customer

with Pump1 2 3 4 5 6 8 9 10

3 100 100

5 100 100

6 100 100

7 100 100

7.5 100 100

9 98 98

12 85 57

15 75 29

18 49 7

21 48 6

35

Alternative 4 and 5

Alternative 436

Alternative 4

Alternative 537

Alternative 5

Alternative 538

Alternative 5

Water Conserved

Remark: *Pressure - Minimum Service Pressure at Critical Point, Negative value in water conserved means water leakage has increased.

Water ConservedAlternative *Pressure (m) Base Demand (%) Water Conserved (m3/day)

A0 7.5 100Alternative 1A1.1 3 100 224.3Alternative 2A2.2 5 90 110Alternative 3A3.7 5 80 109Alternative 4A4.4 9 100 -38.6Alternative 5A5.3 12 100 -102

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Energy Conserved

Alternatives *Pressure (m) Base Demand (%) Energy Conserved (kWh/day)A0 7.5 100Alternative 1A1.1 3 100 40Alternative 2A2.6 5 80 336Alternative 3A3.7 5 80 336Alternative 4A4.4 18 100 422Alternative 5A5.3 18 100 435

Remark: *Pressure - Minimum Service Pressure at Critical Point

40

Energy Conserved

Energy Conserved

Energy Consumption and Minimum Pressure

0.4613

41

Energy Conserved

Alternatives *Pressure (m)

Base Demand (%)

Energy Consumption (kWh/m3)

Utility % of Reduction Costumer % of

Reduction Total % of Reduction

A0 7.5 100 0.1765 0.5 0.6765

Alternative 1

A1.1 3 100 0.1600 9.4 0.5 0.0 0.6600 2.4

Alternative 2

A2.2 5 90 0.1674 5.2 0.5 0.0 0.6674 1.4

A2.6 5 80 0.1674 5.2 0.5 0.0 0.6674 1.4

Alternative 3

A3.1-3.9 0.1765 0.0 0.5 0.0 0.6765 0.0

Alternative 4

A4.4 18 100 0.2157 -22.2 0.2450 51.0 0.4627 30.9

Alternative 5

A5.3 18 100 0.2163 -22.5 0.2450 51.0 0.4613 31.8

Best Alternative in terms of Energy Consumption (kWh/m3)

Remark: *Pressure - Minimum Service Pressure at Critical Point

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• The total energy use by MWA water supply system is 0.2338 kWh/m3 with distribution:• Raw water intake: 0.0097 (4%)• Water treatment: 0.0469 (20%)• Water transmission: 0.0961 (41%)• Water distribution: 0.0811 (35%)

• Total energy used from raw water to tap varies from 0.46 to 0.79 kWh/m3 depending on the hours of pumping by customers. The energy input by MWA and customers vary from 22 to 39% and 61 to 78% respectively.

• As expected, lower pressures can conserve more water because of reduced leakage.

• More energy can be conserved if the service pressures are increased. A reduction of 32% (from 0.68 to 0.46 kWh/m3) in energy consumption can be achieved with 18m of service pressure using PRV.

Conclusions43

Thank you for your kind attentionmsbabel@ait.asia

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