Assessment of Future Water Resources Sustainability Based on 4 National Taps of Singapore

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Luke Simpson
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Faculty of Engineering Department of Civil & Environmental

1 Assessment of Future Water Resources Sustainability Based on 4 National Taps of Singapore National University of Singapore Faculty of Engineering Department of Civil & Environmental Engineering Supervisor: Dr. Pat Yeh By: Foo Chiou Looi (A E)

2 CONTENT 1. Introduction Water resources situation around the world Research motivation Methodology 2. Water resources in Singapore The first tap: local catchment water The second tap: imported water The third tap: NEWater The fourth tap: desalinated water Estimated production costs Alternate sources of water Potential future water supply 3. Water demand in Singapore 4. Water sustainability 2

3 CONTENT 5. Estimated future water demand Domestic Non-domestic Estimated future daily demand 6. Estimated future supply 7. Sustainability index 8. Discussion Future demand Future supply 9. Conclusion 3

4 1. WATER RESOURCES SITUATION AROUND THE WORLD Source: Fry,

5 WATER STRESS INDICES Withdrawal-to-availability ratio, W/Q Classification < 0.1 No-stress 0.1 < W/Q < 0.2 Low stress 0.2 < W/Q < 0.4 Moderate stress W/Q > 0.4 High stress Per capita water availability, Q/c (m 3 c -1 y -1 ) Classification > 1700 No-stress 1000 < Q/c < 1700 Moderate stress Q/c < 1000 High stress < 500 Extreme stress 5

6 WATER RESOURCES SITUATION: ASIA AND SINGAPORE Asia: lowest per capita availability of fresh water Central Asia and parts of Southeast Asia: high water stress Q/c: 110.9m 3 /year high water stress Mean annual rainfall: 2400mm > global average of 1050mm Challenges: limited land space, no natural aquifers and lakes to collect rainwater PUB: Four National Taps 6

7 RESEARCH MOTIVATION Sustainability: development that meets the needs of the present without compromising the ability of future generations to meet their own needs Dry weather: increase in water demand, affects catchment volume available Second tap: not very stable due to the complexity of the relationship between Singapore and Malaysia Third and fourth taps: higher production costs, energy-intensive 7

8 METHODOLOGY Aim: to assess the sustainability of the water resources in Singapore Estimated future supply of each tap Focus: processes of NEWater and desalination Estimated future demand 8

9 2. WATER RESOURCES IN SINGAPORE LOCAL CATCHMENT 1857: donation of $13000 from philanthropist Tan Kim Seng for waterworks 2015: catchment area covers two-thirds of Singapore s land surface Rainwater is collected in the storm water collection system before it is stored in the 17 reservoirs Reservoir Integration Scheme: reservoirs are connected through a system of pumps and pipelines Excess water collected in one reservoir can be pumped into another reservoir for storage to reduce wastage Current storage > 140 million m 3 9

10 IMPORTED WATER 1924: completion of causeway between Singapore and Malaysia 1962: Johor River Water Agreement up to 250 million gallons of water per day (mgd) from the Johor River until 2061 Cost: 3 sen per 1000 gallons of raw water Cost to treat 1000 gallons of raw water: RM : construction of the Linggiu Dam for additional water to be drawn on top of the 250mgd 10

11 NEWATER Plant Year of commissioning Capacity (million imperial gallons) Bedok Kranji Ulu Pandan Changi Total 118 DESALINATED WATER Plant Year of commissioning Capacity (million imperial gallons) SingSpring Tuaspring Total

12 ESTIMATED PRODUCTION COST OF EACH TAP Tap Production cost (S$/m 3 ) Local catchments 0.30 Imported water from Malaysia 0.20 NEWater 0.23 Desalinated water

13 ALTERNATE SOURCES OF WATER Rainwater Harvesting Greywater Recycling Greywater : untreated used water which has not come into contact with toilet waste Use of Seawater 13

14 POTENTIAL FUTURE WATER SUPPLY VARIABLE SALINITY PLANT (VSP) Able to tap water from the smaller streams near the shoreline During rain: production of clean water from canal water Dry weather: seawater desalination Source: 14

15 GROUNDWATER Western and Southern parts of the island: Jurong Formation Consultancy services: Development of groundwater flow model of Jurong Formation Field Investigation Programme Validation Study Jurong island WATER FROM INDONESIA 1991: agreement to provide 1000mgd of water ($0.01/m 3 ) to Singapore from Riau in Indonesia via undersea pipelines 1992: joint venture created to develop supply of water from Bintan and to Bintan and neighboring Riau Islands but project came to a halt due to political uncertainty in Indonesia 15

16 3. WATER DEMAND Current per capita demand (litres/day) Current population Current total domestic demand (litres/day) Current total non- domestic demand (litres/day) Current total demand (litres/day) Current total demand (mgd) ,469, ,646,490 1,005,456,821 1,828,103,

17 4. WATER SUSTAINABILITY Environment and Water Regulations and Standards SEWERAGE AND DRAINAGE ACT Source: 17

18 WATER SUSTAINABILITY Source: 18

19 5. ESTIMATED FUTURE WATER DEMAND ESTIMATED FUTURE POPULATION 8,000,000 7,000,000 y = x 2-1E+07x + 1E+10 R² = ,000,000 Population 5,000,000 4,000,000 3,000,000 2,000,000 Past population Poly. (Past population) 1,000, Years 19

20 ESTIMATED FUTURE PER CAPITA DEMAND Per capita demand (litres/day) Past per capita demand Year 20

21 ESTIMATED FUTURE DOMESTIC DEMAND population daily per capita demand Estimated Estimated future per Estimated future total Estimated future total Year future capita demand domestic demand domestic demand population (litres/day) (litres/day) (mgd) ,560, ,055, ,647, ,217,581, ,260, ,517,917, ,399, ,854,602, ,063, ,218,172, ,253, ,599,168,

22 ESTIMATED FUTURE GDP PER CAPITA 140, ,000 y = x x + 3E+08 R² = ,000 GDP per capita (S$) 80,000 60,000 40,000 Past GDP per capita Poly. (Past GDP per capita) 20, Year 22

23 ESTIMATED FUTURE INDUSTRIAL DEMAND scale GDP per capita Year GDP per capita (S$) Current total nondomestic demand (litres/day) Amount of water used per $1000 (litres) Estimated future total industrial demand (litres/day) Estimated future total industrial demand (mgd) , ,005,456,821 14,098, , ,386,316, , ,121,374, , ,072,109, , ,238,522, , ,620,612, Copyright National University 512, of Singapore 7,218,381,

24 ESTIMATED FUTURE DAILY DEMAND Year Daily demand (mgd)

25 6. ESTIMATED FUTURE SUPPLY NEWater and desalination: 80% of our water demand by : capacity of NEWater plants will increase by more than 160mgd Increase capacity of Changi NEWater plant by more than 50mgd over the next 5 10 years New Tuas NEWater factory: initial plant treatment capacity of 25mgd Kranji NEWater plant will be expanded by 5mgd 25

26 7. SUSTAINABILITY INDEX Water resource sustainability index (SI): If water supply > water demand, SI = (water supply water demand) water supply If water supply water demand, SI = 0 26

27 8. DISCUSSION FUTURE DEMAND Actual population dependent on birth/death rates, immigration/emigration rates Future per capita demand may not follow a linear trend; affected by weather and conservation measures implemented GDP: an economic way of forecasting annual growth rate Results based on extrapolation: the further the estimated year, the more uncertainty 27

28 FUTURE SUPPLY Most possible future sources of water supply: local catchment, NEWater and desalination Water import from Malaysia: past unsuccessful negotiations and the complex relationship between the two countries Water import from Indonesia: high construction cost; project delayed for a long time with no update 28

29 DESALINATION: REVERSE OSMOSIS (RO) External pressure applied on the sea water Water flows opposite to the natural flow across the membrane Dissolved salts left behind the membrane Source: Ghalavand, Hatamipour, & Rahimi,

30 FORWARD OSMOSIS (FO) Source: Ghalavand et al., 2014 Source: Ghalavand et al.,

TOWARDS SUSTAINABILITY Increased market share of Seawater Reverse Osmosis (SWRO) Efficiency improvements Specific power demand in 1980: 10kWh/m 3 Specific power demand now: 3

31 TOWARDS SUSTAINABILITY Increased market share of Seawater Reverse Osmosis (SWRO) Efficiency improvements Specific power demand in 1980: 10kWh/m 3 Specific power demand now: 3 5kWh/m 3, depending on specific conditions and constrains such as temperature and salinity of seawater Renewable energy Solar energy Wave energy Wind energy Geothermal energy 31

32 NEWATER Source: HWBgLI/AAAAAAAAACM/TkwmhxUEsEk/s1600/newater+illustration.jpg 32

33 9. CONCLUSION PUB: water supply and sustainability Sustainability of the local catchment depends on the weather Desalination and NEWater : researches on decreased energy use Extrapolation of data: greater uncertainties for results in the further years population daily per capita demand Comparison of the current demand among different countries to have a better idea of the water demand situation of Singapore System dynamics has been widely used in water resources planning and management 33

34 Thank You Q&A

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