By Dee Camp
Chronicle staff

     A water quality expert with the state Department of Health will be at the Nov. 18 Okanogan City Council meeting to talk about chlorine odors some people have noticed since the city's new arsenic removal system went on line.
     Okanogan is participating in a nationwide U.S. Environmental Protection Agency pilot program to test equipment designed to remove arsenic from drinking water. Okanogan has the only facility in Washington and one of a handful in the West.
     Public works director Ray Clements said water goes through a filtration process and the arsenic ends up in a settling tank. It later goes through the city wastewater treatment plant and ultimately ends up in sludge that's spread on land at the city cemetery.
     Chlorine is used in the process of making arsenic attach to iron in the settling process, Clements said.
     Soon after the plant began operation in late August, city hall began receiving complaints about water having chlorine smell and taste. Complaint locations are being mapped, mayor Michael Blake said during the Oct. 7 and Oct. 21 council meetings.
     What people are noticing is chloramine, a product of chlorine breakdown, said Clements.
     He said well No. 4 is Okanogan's deepest well. Its water contains naturally occurring arsenic and the amount was at a legal level until the EPA changed the allowable level from 50 parts per billion to 10 ppb, he said.
     The city does not otherwise chlorinate its water.
     Morie Block of the city's contract engineering firm, Gray and Osborne, told the city council Nov. 4 that the residual chloramides will go out into the system and dissipate.
     He said the problem is more of a mindset about chlorine than anything else. He added that chlorine doesn't have a taste, only an odor that can make people think they taste it.
     "Yes, it is a perception thing, but regardless, it's a problem," said councilman Craig Nelson. "It's an annoyance to people."
     He said he filled the tub recently to bathe his small child and "I thought I was at the pool" because of the chlorine smell.
     "I notice it at my house. It's a strong, chlorine-type smell," he said. "Is this something we're always going to have?"
     Clements has said his crew is trying to find the proper balance of chlorine to do the job in the arsenic plant but not produce a chlorine smell for customers.
     "The bugs are solved with the operation of the arsenic filter system and the pilot study is in full swing, with samples being sent to Battelle's lab in Cincinnati, along with tracking chemical use for costs of operation," he wrote in a Nov. 4 report to the council.
     The plant is removing the arsenic below the 10 ppb level, he added.
     Block told the council the city crew can set the concentration of chlorine into the filter system.
     He and Clements also noted there's a difference of opinion between two of the plant's equipment suppliers about what to do about the chlorine smell.
     Clements said well No. 4 is supplying the bulk of the city's water now, because of smaller winter demand and because of the pilot project, but in the summer, other wells will come on line to meet demand.
     "Dilution may be the solution," he said.
     "That'll work in July and August, but there are 10 other months in the year," said Nelson, who noted that he also notices the smell at his office in the Ag Service Center at the south end of town.
     Clements said the demonstration portion of the project will end next year and the city then will be free to lessen pumping from that well.
     "We want to reiterate that it is a demonstration project and encourage the public to be patient," said councilwoman Joan Pfeiffer.
     Clements said some people seem to be more sensitive to the chlorine smell.
     Councilman Steven Gadd said he lives a block from the arsenic plant, which is at South First and Tyee, and doesn't notice the smell, but councilwoman Tracey Nicholas Orr, who lives several blocks southwest of the plant, said she notices the smell.
     Blake said he wants city residents who have concerns or questions about the chlorine odor to attend the Nov. 18 council meeting, which starts at 7 p.m. at city hall.
     Pre-meeting questions may be directed to Justus at (509) 456-2453 or tom.justus.@doh.wa.gov.