Location:
George Town, Cayman Islands
Capacity:
2.64 million US gallons per day
Type:
Seawater Desalination
Technology:
Reverse Osmosis
Contract Type:
DBO
About the project
Located in George Town, on the island of Grand Cayman, this plant was the fifth seawater desalination facility, designed, built and operated by our company for the Water Authority-Cayman. This 2.64 million US gallon per day state-of-the-art seawater reverse osmosis desalination facility was completed in 2024 and replaced a 1.32 million gallon per day facility that was originally designed, built and operated by CWCO in 1990.
Scope of work in the contract includes design, procurement, construction and operation of seawater abstraction wells, concentrate disposal well, feedwater pretreatment system, two electrically driven seawater reverse osmosis plants, isobaric energy recovery system, post-treatment and product delivery system, Category 4 hurricane resistant concrete building, and ancillary equipment. A standby diesel generator is installed to support up to 50% of the plant’s operational capacity in the event of a power outage, such as during a major storm. This plant produces finished water with a TDS of less than 200 ppm by passing some of the desalted seawater through a ‘second pass’ brackish water reverse osmosis system.
Because the cost of electricity on Grand Cayman is typically 4 to 5 times greater than in the United States, a critical design and operation factor for this plant is/was the overall energy efficiency of the facility. The plant utilizes ultra efficient centrifugal high-pressure pumps with ERI isobaric work exchangers and uses less than 10.9 kWhrs of electrical power to produce 1,000 US gallons of product water, inclusive of power for feedwater pumps, post-treatment and product water delivery to the client’s reservoirs.
Raw seawater for the plant is obtained from seawater wells located on site, which avoids the need for expensive pretreatment equipment and chemicals associated with open sea intakes. However, the raw seawater does contain hydrogen sulfide, which is removed from the final product using a degasifying tower and air scrubber system.
This plant is operated under a 10-year O&M contract for the Water Authority – Cayman.
