The Water & Power Authority (WAPA) on St. Croix reached out to Seven Seas Water Group for a temporary solution to ensure a constant water supply when an existing thermal desalination plant was slated for repairs. Seven Seas has an active presence and extensive history in the region.

Seven Seas proposed using mobile seawater reverse osmosis (SWRO) units to promptly meet the need with no upfront capital investment required from WAPA. With a build-own-operate (BOO) contract through its Water-as-a-Service® offering, Seven Seas had six highly efficient SWRO units up and running within 92 days of the signing of the contract. Seven Seas assumed responsibility for managing and operating the new facility, ensuring a dependable water source at a fixed cost per gallon throughout the entire agreement.

When WAPA saw that Seven Seas’ SWRO installation could deliver guaranteed water quantities at a significantly lower cost than initially estimated – and take over the burdens and risks associated with operating the equipment – the client asked Seven Seas to expand the supply scope from 500,000 GPD (1,892 m³/d) to 1,500,000 GPD (5,677 m³/d), and to lengthen the term of the contract to allow for the refurbishment of additional thermal units.

The Seven Seas plant, which was engineered to maximize uptime, was able to produce potable water with a salinity level below 300 ppm TDS from a feedwater source containing 35,000 ppm TDS. The plant’s design is the most energy-efficient option available commercially, with the reverse osmosis (RO) portion consuming approximately half the power of most containerized RO units.

This exceptionally efficient design not only ensured a cost-effective temporary water supply to the residents of St. Croix, but also operated in an environmentally sustainable manner, exemplifying responsible stewardship of resources.