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Caribbean Environmental Health Institute (CEHI) Tel.: 1 758 452 2501; Desalinization Plants in Selected Caribbean Countries.

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Presentation on theme: "Caribbean Environmental Health Institute (CEHI) Tel.: 1 758 452 2501; Desalinization Plants in Selected Caribbean Countries."— Presentation transcript:

1 Caribbean Environmental Health Institute (CEHI) Tel.: ; Desalinization Plants in Selected Caribbean Countries Presented at International Seminar On Techniques To Increase Water Availability In Areas Where A Shortage Occurs Santiago, Chile: 17 – 18 December, 2005 By Herold Gopaul

2 Outline of Presentation  Introduction  Why Desalinization  Desalinization Plants in Selected Countries (Antigua and Barbuda, The Bahamas, Barbados, British Virgin Islands, Grenada, St. Lucia and Trinidad and Tobago)  Summary of Issues  Recommendations

3 Map of the Caribbean

4 Introduction The desired future for the Caribbean is a sustainable future where water resources management will be integrated, effective and efficient (Vision on Water, Life and the Environment for the 21st Century for the Caribbean). Sustainability of the region's water resources dictates that land and water management should be interdependent and indivisible.

5 Introduction - Water Resources Management Issues in the Caribbean Viewed globally, the region is well endowed with water resources however, problems with accessibility and distribution – some are water scarce (Barbados ranked 15 th most water scarce in the world) Per capita water availability will shrink to half by the year ( Rapid population growth and trends in urbanization, tourism, rural development, and agricultural and industrial development )

6 Introduction – Water Resources Management Issues in the Caribbean Human activities influence both the availability and quality of the water resources Land-based pollution and contamination of freshwater resources

7 Integrated Water Resources Management Issues in the Caribbean Seasonal influx of Tourists Tourism is dependent on the quality of the coastal areas and has a potentially significant negative impacts on the water resources (consumption is 7 – 9 times that of local consumers) Over-extraction of groundwater has led to depletion of water resources leading to reliance on desalination with consequential economic impact

8 Introduction - Water Resources Management Issues in the Caribbean Highly dependent on rainfall to feed surface intakes and replenish groundwater. (problems with rainfall patterns and geology) Potential impacts of CV/CC and sea level rise Poor land use planning and soil management in watersheds reduce freshwater capturing capacity, affect coastal water quality and aquatic bio-diversity. Rio Grande River, Jamaica

9 Why Desalinization? Countries resort to desalination either: To address historical water scarcity situation: Barbados, BVI To augment conventional sources: Trinidad, Grenada, St. Lucia To augment supplies where other augmentation methods are not in wide spread use: barging in the Bahamas, RWH in Grenada and Antigua To ensure some level of sustainability and reliability To address issues of remoteness from central suppliers: the Bahamas, Barbuda

10 Desalinization Plants in Antigua & Barbuda Situation: No significant surface water Prone to drought (40.98 inches) Limited land space for surface catchments; reservoir-dependent Insufficient groundwater Stipulated Rooftop RW catchments and storage Government agreed to Desalinization for supply augmentation Easy access to feed stock Cheap electricity (at the time; late 1980s)

11 Desalinization Plants in Antigua & Barbuda Comparative Costs of Water Production Ground Water : US $2.50/cubic metre Surface Water : US $3.00/cubic metre Desalinated Water: US $4.70/cubic metre Government subsidies Desalinated water by US$2.50/1,000 gals.

12 Desalinization Plants in Antigua & Barbuda Technology Reverse Osmosis – using sea water Multi-Stage Flash Distillation dual electricity generation facility – using sea water (18.2 MW and 2mgd of water) Daily Water Production by Type (Gallons/day) Ground Water : 450,000 (non-drought conditions) Surface Water : 700,000 (non-drought conditions) Reverse Osmosis: 2,000,000 Multi-Stage Flash Distillation: 2,000,000

13 Desalinization Plants in Antigua & Barbuda Ownership 2 MSFD – private (sells water & electricity to the State) 1 RO – Government 5 ROs – Private – 2000,000 mgd each (Build, Operate, own and transfer – sells water to the State) 1 RO 27,000g/d on Barbuda - Private – (Build, Operate, own and transfer – sells water to the State) A number of small ROs privately owned and operated (do not sell water to the State)

14 Desalinization Plants in the Bahamas Situation: 700 islands and cays Only 3 islands has significant water resources Where groundwater is found in natural aquifers – concerns of sea level rise on quality Supply Augmentation includes barging; groundwater abstraction and rainwater harvesting RWH is not very popular as a result of seasonal variability, making supplies unreliable Groundwater can be costly: land acquisition and cost of pre- treatment Cost of desalinated water in New Providence is comparable to barging from islands; it has superior quality, reliable and sustainable

15 Desalinization Plants in The Bahamas Technology Reverse Osmosis – using sea water; borehole water Multi-Stage Flash Distillation – using sea water; borehole water Vapour Compression Distillation - using sea water

16 Desalinization Plants in the Bahamas Ownership 1 RO – Government (444,000 gpd) 2 MSFD – Government (672,000 and 1,200,000 gpd) 1 VCD – Government 12,000 gpd average) A number of ROs - Build, own, operate and transfer – private (sells water to the State) A number of ROs privately owned and operated (do not sell water to the State) Over 200 ROs plants in operations in the Bahamas

17 Desalinization Plants in the Bahamas Issues ROs Plants have been customized to use diesel fuel Increase consumption of desalinated water Desalinated water has replaced groundwater an the main source Challenges include vulnerability of the system to natural disasters; disruption of electricity and quality of the feed stock

18 Desalinization Plants in the Barbados Situation: Limestone cap below surface catchments allows for natural aquifer Groundwater accounts for 80% of fresh water and 98% of potable water prior to desalinization Concerns over the contamination of the groundwater Ranked 15 th in the world in water scarce countries Heavily dependent on rainfall Increase in per capita of water (agriculture, manufacturing and tourism) Measures to protect water resources; zoning, incentives, building requirements for RWH

19 Desalinization Plants in Barbados Technology Reverse Osmosis – using brackish water from wells and seawater Ownership 1 RO – Private (build, own, operate, transfer; sells water to the State) using brackish water 1 RO – Private (build, own, operate, transfer; sells water to the State; no longer in operation) using brackish water I RO – Private; does not sell water to the State; use for landscaping and golf course; uses seawater

20 Desalinization Plants in Barbados Issues Desalinated water is mixed with chlorinated groundwater The is now a greater acceptance to using desalinated water through PA/PE The cost of desalinated water is slightly higher than that of groundwater (brackish water is of high quality – low salinity) The brine can be reintroduced into deep borehole near the coast with affecting the receiving waters Challenges include vulnerability of the system to natural disasters; disruption of electricity, cost of energy and quality of the feed stock if TDS rises

21 Desalinization Plants in the British Virgin Islands Situation: Made up 23 of islands and cays Limited freshwater Heavily dependent on tourism Water sources – seasonal streams and springs, wells and rainwater harvesting RWH not suitable for large scale application such as the tourism industry 95% of the water is provided by the State 90% of water consumed is by domestic users 2 mgd is the estimated requirement of water in the BVI

22 Desalinization Plants in British Virgin Islands Technology 7 Reverse Osmosis – using sea water; privately owned, sell water to the State 1 Multi-Stage Flash Distillation – using sea water; generates electricity and produces water and sells to the State

23 Desalinization Plants in British Virgin Islands Issues Plants are established under the build, own, operate, transfer arrangement Government may allocate State-own land for the establishment of the plants Desalinated water is purchased by government at an average cost of US$18.60/1000gallons Cost of production of desalinated water ranges from US $20.00 per 1000 gallons Plant operators and all but one manager are locals,

24 Desalinization Plants in Granada Situation: Tri-island state; Grenada, Carriacou and Petite Martinique Significant surface and spring water in Grenada Carriacou and Petite Martinique rely on RWH and to a lesser extent on groundwater

25 Desalinization Plants in Grenada Technology 3 Reverse Osmosis – using sea water; owned and managed by the State Some hotels have small ROs plants using seawater Grenada – 400,000 US g/d Petite Martinique – 30,000 g/d Carriacou – 100,000 US g/d Cost of production EC $18 – $20/1000 gallons Cost to consumer – EC $0.02/gallon

26 Desalinization Plants in Grenada Issues Plants are plagued by operational and maintenance problems No service contract with manufacturer – full cost for any assistance Storage capacities in Petite Martinique and Carriacou is insufficient – production is a function of immediate demand Plants are therefore unused for long period Damage to suction pipe from recent severe weather conditions Low public acceptance of desalinated water in Petite Martinique and Carriacou

27 Desalinization Plants in St. Lucia Situation: Rainfall varies across the island ranging between 1,200 mm – 3,500 mm Most of the rainfall drains to the sea Government does not utilize desalinization as a supply augmentation option; groundwater exploration is preferred

28 Desalinization Plants in St. Lucia Technology 2 Reverse Osmosis – I using sea water and the other brackish water; owned and managed by private hotels to augment the water authority supply A number of RO plants are coming on stream with the construction of tourism facilities on the Island

29 Desalinization Plants in Trinidad & Tobago Situation: Surface (65%) and groundwater (25%) Desalination (10%) Unaccounted for and illegal access (51%) Increase in water production for the period 1997 – 2002 ( m/gallon) Country heavily industrialized Need for a reliable supply to the industrial estate

30 Desalinization Plants in Trinidad & Tobago Technology 1RO Plant – using sea water owned and managed by private joint venture (local and foreign partners); 22mgd Build, own, operate and sell after 20 years arrangement Half the production is sold to the industrial estate through the water authority

31 Summary of Issues The main technologies currently in use: Thermal technologies Multi-stage flash distillation Multiple effect distillation Vapour compression distillation Membrane technologies Brackish water reverse osmosis Seawater reverse osmosis

32 Summary of Issues Reverse osmosis appears to be replacing the thermal technologies Thermal technologies persist where this is coupled with electricity generation

33 Summary of Issues Tendency towards design-build-own- operate contracts with manufacturers resulting in: Contractual agreements to sell water exclusively to contracting agency/industry Reduced need for resident expertise

34 Summary of Issues National Policy Generally addressed water resource management but not specifically desalination Water scarce countries more likely to have policies Not all were formal or even written

35 Summary of Issues Desalination likely to increase More expensive than processing surface and groundwater Poor public reaction can be linked to poor public education where water scarcity is an emergent problem and consumers are used to other traditional sources.

36 Summary of Issues Pricing structures in some countries: Reflects production costs Are subsidized by government and varied by user category Appears to elicit less sensitivity in geographically water scarce countries

37 Recommendations Governments should adopt a structured approach to the implementation of desalination: Establish national policies within the framework of national water resource management plans Involve stakeholders especially those with a regulatory role Establish clear procedures and guidelines for specifications, applications, implementation and monitoring of desalination plants Where rainfall is reliable; encourage other less costly augmentation options such as RWH

38 THANK YOU FOR YOUR ATTENTION


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