Environmental Science & Engineering - www.esemag.com - March 2004
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Membrane filtration process installed in Newfoundland community

The Fyne process is based on nanofiltration, which allows inorganic ions to pass through the membrane with the filtrate. The organic compounds that cause the high colour content and disinfection by-products, are held back and retained in a small proportion of the raw water known as the concentrate or reject.

When the Conne River Micmac Band sought to ensure the availability of safe drinking water with a new filtration system, studies showed that organic materials from surface water had to be removed prior to chlorination.

The Conne River Micmac Band has an on-reserve population of approximately 700 people and is located on the south east shore of Newfoundland. The Reserve is 560 km from St. John’s and 180 km from the nearest services centre, Grand Falls.

“The Band currently get their drinking water from a surface source located in the Southwest Pond watershed,” explains Eric Humphries of Design Management Group Ltd. (DMG), the Band's engineering consultant.

The consultant selected a process plant which uses proprietary membrane filtration technology from ITT Sanitaire’s PCI Membrane Systems Unit. Known as the “Fyne” process, the filtration plant could produce 1.3 million litres/day (MLD) of clean drinking water and would be immediately effective in providing safe, highquality potable water to Conne River residents. It includes provisions to meet future needs, which might include the construction of a fish processing operation. With this and other possibilities in mind, the plant was built to allow for easy expansion to 1.6 MLD.

The Fyne Process offers several advantages to the community. No chemicals are added to the water prior to chlorination and there is no residual chemical sludge to dispose of. Savings on chemical purchases and sewagedisposal costs quickly outweigh the marginally higher system price. In addition, the process membranes provide a physical barrier that holds back water-borne pathogens, microbes and viruses, as well as reducing undesirable levels of iron and other metals, which may also be found in surface water.

With DMG's help, a multiple-factor- comparison analysis was used to evaluate the suitability and economy of different methods of water treatment and the PCI system was one of two approaches that were piloted.

The Conne River facility, the largest of its kind so far, will be the first Fyne process installation to use spiral nanofiltration membranes rather than the tubular membranes used at earlier Canadian projects, which involved smaller water volumes. These projects included plants installed at First Nation communities at Chapel Island, Nova Scotia, and at Middle River, British Columbia. The spiral membranes were thought to be more economical for handling the high water volumes at Conne River.

The Fyne process is based on a particular process known as nanofiltration. Surface water is prefiltered to remove suspended solids down to 10 microns. This pre-filtered raw water, which still contains large quantities of organic compounds, is then passed, under high pressure, through a series of membrane modules. A fraction of the feed water passes through the membrane, which holds back the disinfection by-product precursors, along with iron and other undesirable metals, and water-borne oocysts, bacteria and viruses. These undesirable components are automatically flushed from the system with unused feed water (merely raw water in a more concentrated form) and returned to the river with no chemicals added to it.

The clean water that has passed through the membrane (the filtrate) can then be safely chlorinated and delivered to the potable water distribution system. After treatment, it is effectively colourless and has very low disinfection by-product levels.

The Fyne plant operates automatically, with very little supervision. In fact, the system can be monitored continuously and remotely through an outside telephone line. Minimal routine maintenance includes bi-weekly cleaning of the spiral membranes using prefiltered feed water and detergent (similar to common household laundry soap). No other chemicals are used, so there are no storage or disposal issues. After cleaning, membrane wash water is stored on site and metered back into the river in accordance with strict environmental standards.
Contact Bjorn von Euler at ITT Fluid Technology, e-mail: bvoneule@fluids.ittind.com

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