Pumps that still shine in brine

Turning seawater into drinking water requires equipment that doesn’t corrode. In Adelaide, Australia, a new desalination plant saves money with conventional pumps backed by a proven track record.

By Nancy Pick, Photo Xylem, Istockphoto

IN DROUGHT-PRONE AREAS from California to Qatar, locals turn to seawater desalination for their drinking water. Reverse-osmosis plant designers in those areas, nervous about the new technology and the potential for corrosion, tend to favor special pumps made from stainless-steel alloys.

But Xylem provides a better solution: conventional iron pumps strengthened against corrosion with epoxy coating and cathodic protection.

Currently, a large, new desalination plant in Adelaide, Australia, is being built by Acciona Agua of Spain. The facility will use 18 standard Flygt submerged pumps from Xylem to move 100 gigaliters of seawater and brine per day for the treatment process. Production is due to begin in April, 2011.

Xylem has extensive experience pumping seawater for such applications as cooling systems, drainage and fish farming. Still, before getting the contract, Xylem had to prove the reliability of its conventional pumps in reverse-osmosis plants. Initially, designers worried that the iron in conventional pumps might corrode and clog delicate membranes.

Xylem directed their attention to the Alicante II desalination plant in Spain. Its eight Xylem Flygt CP-3240.865 (375 kW) pumps send seawater to pre-treatment before reverse osmosis. So far, Xylem inspectors in Spain have found no corrosion problems.

“These references were critical in the final decision” to order Xylem’s conventional pumps, said Manuel Manjón Vilda, International Construction Director for Acciona Agua, who oversees the plant in Adelaide.

“In addition to costing one-third the price of pumps made from special alloys, conventional pumps are faster to deliver and repair,” said Javier Carrillo de Albornoz, Treatment Manager at Xylem Spain.

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