Embracing Desalination

Brian Fraser and David Osgood

The residents of Brockton, Mass., can finally water their lawns. This is a big deal because Brockton is transitioning from water bans to water surplus, ending a century-long water shortage. The industrialized and densely populated suburbs around the Boston area continue to grow, which has put a strain on the aquifer that supplies groundwater for municipal drinking water. To end the shortage once and for all, the city has embraced desalination.

The development by Inima USA of the first large-scale desalination plant in New England has allowed Brockton and surrounding communities to supplement existing groundwater with desalted surface water from the Taunton River. Tides carry ocean water far inland along the river, so its water quality is in a continuous state of flux.

To resolve quality issues, Inima USA was awarded a design-build-operate contract to provide a regional desalination plant. The Kansas-based Layne Christensen Company provided the reverse osmosis (RO) equipment and related services. After extensive pilot testing of the pretreatment and RO and long discussions about the intake and brine discharge processes, the Massachusetts Department of Environmental Protection and the community accepted a desalination solution.

The system is comprised of three skids, each with an initial flow of 1.1 million gal per day (mgd), using a 24:12 single pass array. The membrane treatment plant was designed with expansion in mind. By adding pressure vessels and membranes, the future build-out potential is for 2 mgd, each using a 36:12 array. Because of their large size, skids were built in two pieces for shipping purposes and then bolted together onsite.

Each unit was provided with a local control panel that communicates via Ethernet to the master control panel to eliminate the need for extensive field wiring. Layne's comprehensive services included membrane installation and startup. Remote monitoring of the system performance using the Internet was made available as part of the overall service support structure that the company provides, in addition to local and regional service technicians and membrane process experts if needed.

Fourteen miles from the mouth of the Taunton River, on the West bank, the newly constructed Taunton River Desalination Plant has an initial capacity of 5 mgd and can be expanded in the future to 10 mgd. Not only does Brockton have ample water to satisfy its needs into the foreseeable future, it has a sellable surplus for surrounding communities, making future growth and development possible.