Reverse osmosis technique purifies drinking and engine water

Over the past 20 years, ENWA (formerly MT Freshwater) has high quality, simple to operate, very reliable water treatment units working on the principle of reverse osmosis.

Over the past 20 years, ENWA (formerly MT Freshwater) has high quality, simple to operate, very reliable water treatment units working on the principle of reverse osmosis. The complete absence of corr-osion problems, resistance to bacterial growth and low operating costs are the principal advantages of the units, which produce drinking water to World Health Organization standards from feedwater with a salinity of up to 4.8% in one pass. The company also provides pre-filtration equipment to remove particulates and post-treatment units to replace minerals and adjust the pH of the water.

Standard units are available off-the-shelf capable of producing up to 35 cu meters/day of pure water - ample for offshore use. To give some idea of scale, domestic requirements are typically up to 0.15 cu meters/person/day, while hotels use around 0.25 cu meters/person/day. Units of this capacity cost in the region of $30,000, but operate for about $1.00/cu meter, including power, filter and membrane changes, chemicals and servicing. Average life expectancy of the membranes is typically five years under continuous operation.

The costs come down steeply as the scale of the units increases. A system capable of producing 300 cu meters/day will cost around $160,000 and have running costs of $0.6/cu meters. In the largest project undertaken by the company so far, a village in Poland was supplied with a plant capable of producing 10,000 cu meters/day.

Most of the units supplied by the company are much smaller than this. Main customers come from the defense, marine, offshore, pharmaceutical and electronics sectors, the power industry, where units are used to produce turbine feedwater, and emergency relief organizations. Enwa currently is in discussions with a leading diesel engine manufacturer with a view to supplying units for producing pure water for injection into their latest engines, a practice which is known to reduce emissions and improve performance.

For more information contact Christian Eklund, ENWA. Tel: +46 31 742 92 50, Fax: +46 31 742 92 60, E-mail christian.eklund@enwa.se

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