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Efficient Ultra Pure Water Production

The production of electricity at the USVI Water & Power Authority (WAPA) Randolph Harley Power Plant in the US Virgin Islands depends on a reliable supply of ultra-pure water. WAPA’s existing system was dated and inefficient resulting in costly production of make-up water.

Seven Seas Water partnered with WAPA to provide 550,000 GPD (2,081m3/d) of ultra-pure water under a Build-Own-Operate (BOO) arrangement for 20 years. The plant was up and running in a mere 97 days meeting the EPA’s discharge mandate.

From a seawater reverse osmosis permeate; Seven Seas Water’s system utilizes brackish water reverse osmosis that produces high-purity water at 5 μS/cm, and electro deionization that produces ultra-pure water at 0.06 μS/cm. Each process step is operating at 90% recovery. The plant is sized so all components are 100% redundant to meet their estimated nominal production requirement of 235,000 GPD (880 m3/d).

Seven Seas Water managed all aspects of the project with no upfront capital requirements from WAPA and is currently responsible for 24/7/365 operations of the ultra-pure water plant.


The material contained in this case study is provided for informational purposes only. The information contained is accurate only as of the date the case study was issued. Seven Seas Water disavows any obligation to update information contained in this case study after the date of issuance.