An innovative intake micro-filtration system has been installed in a 10-million-gallon-per-day desalination facility that utilises reverse osmosis to produces potable water for a city in the US. The intake design, aimed at minimising environmental impacts associated with entrainment and impingement, incorporates micro-filtration elements manufactured by Filtrex, Attleboro, MA, USA, in a stainless steel structure fabricated by BEPeterson, Avon, MA.
The design has been installed by Inima, which is operating the desalination plant, and Hanson, Murphy and Associates (HMA) of North Easton, MA.
The facility where the innovative system was installed is the Taunton River Desalination plant owned by Aquaria Water LLC. The company is a joint venture between Inima and Bluestone Energy and was created to provide drinking water for Brockton city, MA.
“For many surface water intakes, impingement/entrainment issues related to marine life forms are a growing environmental concern. There are currently few, if any, methods of dealing with this problem directly,” said Jeff Hanson, Hanson & Murphy. “HMA has investigated this problem in the context of surface water intakes in the application of water treatment systems. As a result of our investigation and testing into the issues of entrainment and impingement, we believe that the intake filter utilising the Filtrex technology provides a solution that is both direct and unique.”
Sohail Zaiter, president of Filtrex, explains that the Filtrex filter system is an application of an industrial filter in which water passes through “candles” consisting of stacks of plastic wafers. Micro grooves in each wafer allow water to pass through very small passages. Considerable surface area and low approach velocity are achieved in a relatively small space with modules containing multiple candles.
Thirty modules
“The current design for the TRDP delivering 21,000 gallons per minute (gpm) would employ 30 modules each consisting of 96, 4.6-inch-long candles. With this design an intake velocity of 0.204 feet per second is achieved. Candles can be cleaned by sequentially turning them off, at which time impinged material tends to drop off and be swept away by river flow,” Zaiter said.
Alfredo Andres, general Manager of Inima USA, said the filtration system had been approved for use by the Massachusetts Department of Public Water Resources.
“We are looking forward to being on the cutting edge of this innovative water filtration technology. The entrainment and/or impingement of fish, larvae, fish egg, and other biota have been a long standing problem in the design of intake systems for withdrawal of large quantities of water from surface water sources. As part of the Clean Water Act Section 316(b) rules, the EPA monitors and regulates ‘the location, design, construction and capacity of water intake structures’ to require that they reflect ‘the best technology available for minimising adverse environmental impact(s).”
Andres said Inima believed the intake filter system being deployed was the best technology to address issues for the desalination project. BEPeterson fabricated the stainless steel intake filter housing to specifications provided by Hanson & Murphy.
BEPeterson’s expertise
Hanson said the choice of BEPeterson as the fabricator of the components was based on BEPeterson’s experience, facilities and their willingness to work with initial conceptual designs. They met a tight delivery schedule and provided the quality that we demand from our suppliers. They are a well-established ASME and TUV certified welder which gives Hanson & Murphy the confidence that our intake filter housings will be fabricated to the highest standards”.
Zaiter said, “ As demand grows for municipal water filtration, Filtrex will continue to be a significant supplier of innovative Filtex filter systems and our partnership with BEPeterson will be a critical part of our success”.
Daniel Szczurko, sales and marketing director of BEPeterson, said, “The relationship with Inima, Hanson & Murphy and Filtrex has been built on a responsibility to meet the project requirements though a commitment to a project plan and a thorough understanding of the product requirements. BEPeterson has made a commitment to the water filtration market and will work with Hanson & Murphy and Filtrex on all future requirements”.
