Caribbean Environmental Health Institute (CEHI)

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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

• Caribbean Environmental Health Institute (CEHI)
• Tel. [phone] Email hgopaul_at_cehi.org.lc

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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

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Map of the Caribbean
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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.

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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 15th most water scarce in the
  world)
• Per capita water availability will shrink to half
  by the year 2025.
• (Rapid population growth and trends in
  urbanization, tourism, rural development, and
  agricultural and industrial development)

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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
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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
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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.

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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

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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)

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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
  US2.50/1,000 gals.

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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

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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)

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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

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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

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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

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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

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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 15th 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

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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

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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

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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

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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

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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 US18.60/1000gallons
• Cost of production of desalinated water ranges
  from US49.00 - 20.00 per 1000 gallons
• Plant operators and all but one manager are
  locals,

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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

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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

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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

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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

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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

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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 (276.8 346.7 m/gallon)
• Country heavily industrialized
• Need for a reliable supply to the industrial
  estate

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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

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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

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Summary of Issues

• Reverse osmosis appears to be replacing the
  thermal technologies
• Thermal technologies persist where this is
  coupled with electricity generation

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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

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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

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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.

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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

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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

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THANK YOU FOR YOURATTENTION