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Coupeville's water should improve

"Theoretically, Coupeville’s water supply more than doubled Wednesday when the water treatment plant at Fort Casey went back on line.Now, instead of drawing water from the two wells in town only, residents and businesses should be able to draw from the five wells at the Fort Casey well field. Should.But first, Coupeville Public Works Director Larry Harmon says the town will run its new wells at about half capacity until he’s sure that a chlorine treatment system can keep up with the load.Eventually, if all goes well, the Fort Casey well field could supply as much as two-thirds of the town’s 250,000 gallon per-day demand, or about 172,000 gallons a day, Harmon said.More importantly, for many residents: It could make the town’s generally foul tapwater taste a little better. Last Wednesday marked the second time the six-month-old, $400,000 plant has been operational since construction was completed last May.Three weeks after the plant first opened, filter-clogging bacteria caused town officials to shut it down.Since then, Harmon said, town workers have disinfected the filters, drained and cleaned the holding tanks and injected low levels of chlorine into the wells to control bacterial growth.In addition, Harmon said, plant workers are injecting ozone into the treatment system to help separate and solidify manganese and iron particles so they can be filtered out.Coupeville has long wanted to draw water from the wells at Fort Casey to help quench the town’s quarter-million-gallon-per-day thirst — an average of 158 gallons per day for 1,580 residents.The problem is, the water from the wells contains high levels of manganese and iron and emits a rotten-egg bouquet if not treated.Harmon said the plant’s designers anticipated treating the levels of manganese and iron when they designed it, and that the plant successfully filtered out the minerals during pilot tests in May. But the pilot tests lasted only three weeks, before the bacteria problem forced the town to shut them down.“What they didn’t anticipate was the levels of bacteria,” Harmon said. “They didn’t even test for that, and bacteria is really causing the problems.”Bacteria clogged the filters and actually fed on the manganese coating on the filters. The result, Harmon said, was even more manganese going into the plant.The town shut the wells down, then cleaned the filters and started pumping ozone — instead of compressed air — into the treatment system to help get the manganese and iron out of solution so it can more easily be removed. Pumping started again on Wednesday, but this time, it’s taking it slow.“So we’ve finally got it working and now we’ve got to get the production rate up to meet the supply of the Fort Casey wells,” Harmon said.Harmon said the ozone generator the town is using is on loan from a supply company.“The strategy is to inject chlorine into the water before it gets to the treatment system, then we can get away from using an ozone generator,” he said. “But the problem is you can’t dose it very heavily because chlorine will damage the filter material too.”Either way, the budget for the treatment plant includes money for a $9,500 ozone generator if the chlorine proves too corrosive to the filters.“We’ll try a few more things and the chlorination and run at a higher production rate for a while and then make a decision to install an ozone generator,” Harmon said.Meanwhile, Harmon said , encouragement has been flowing in from Coupeville residents.“Several people have called already and said they could tell when we were running from Fort Casey, that the water was better,” he said."

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