Location:
Nassau, The Bahamas
Capacity:
2.6 million US gallons per day
Type:
Seawater Desalination
Technology:
Reverse Osmosis
Contract Type:
DBOO
About the project
This desalination facility initially started production in December 1997 and produces 2.6 million US gallons per day for the Water and Sewerage Corporation of the Bahamas. A complete replacement plant of the same capacity was commissioned in 2019. The desalinated water produced by the facility is used in the public drinking water supply for the island.
The facility operates under a design, build, own and operate agreement with the Water and Sewerage Corporation. Until the completion of the Blue Hills plant in July, 2006, which is also located on the island of New Providence and operated by Consolidated Water, the original facility was both the largest seawater reverse osmosis plant operated by the Company and the largest seawater reverse osmosis plant ever built in the Bahamas.
Feedwater for this facility is abstracted from six shallow seawater wells drilled in karstic limestone and dolomite. Concentrate (brine) from the desalination process is injected into two deeper disposal wells in the same formation. Horizonal and vertical separation of the abstraction and disposal zones, the high permeability of the limestone and the heavier relative weight of the concentrate ensure no mixing of concentrate with feedwater.
One of greatest successes at this plant was overcoming challenges with the feedwater which previously caused excessive fouling of prefilters and RO membrane elements. Through persistent scientific analyses and utilizing our significant operational experience, we were able to identify and mitigate this feedwater fouling and the plant now delivers weekly water volumes consistently in excess of the contractual guarantee, at energy efficiencies consistently better than contractual guarantees.
The facility was designed with a full second pass membrane system, which means the desalinated water delivered to the Water and Sewerage Corporation contains less than 50 parts per million (ppm) of total dissolved solids. This allows the customer to blend the product water from the plant with the higher salinity ground water.
The plant includes a stand-by diesel driven generator, which along with the diesel driven high pressure pumps, allows the plant to be fully functional even when utility power is unavailable, as may occur during a hurricane. The capital works also included the installation of a 6.0 million US gallon welded steel reservoir. Total reservoir storage capacity on site is 18.0 million US gallons.
