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Ozone will rid water of 'musty' taste By MELISSA MARTIN When Jeff Smith took a drink from his kitchen tap on the hottest days of August, the water tasted a little musty. But then he drove to work to do something about it. Smith is the engineer in charge of a $5.6 million ozone facility that will improve the taste of the region's drinking water. The new system will be on line next summer at the Robert Duff Treatment Plant on the Rogue River near TouVelle State Park. "We've always had good-quality water from the springs," said Smith, who lives near the Rogue River, the city's summer supply. In the winter, the Medford Water Commission's 100,000 customers depend on 26.4 million gallons that flow daily from underground springs near the base of Mount McLoughlin. How ozone treatment works Ozone is one of the most effective ways to oxidize algae byproducts and minerals and kill bacteria, viruses and other foreign invaders in water. The treatment process starts with a 9,000 gallon tank of pure liquid oxygen, similar to what hospitals use for breathing machines or other medical purposes. The liquid oxygen (O2) is vaporized and energized with a lightning bolt-like charge to turn it into ozone (free oxygen molecules attaching themselves to each other to make O3). "O3 is very unstable and therefore has a very short and reactive life span," said James Stockton, water plant supervisor. The ozone is injected into Rogue River water - about 18 million gallons worth on an average summer day. The water meanders through a maze for about 10 minutes so the ozone can do its job of attacking invaders. The water continues on through the regular filtration process at the Duff Treatment Plant. Ozone that hasn't reacted with other compounds floats to the head space of the contact basin. It's pulled out and converted back into oxygen, which is released into the air. "We're just trying to make both sources of water taste similar to each other, so there isn't a difference between water that flows to the east side and water that flows to the west." Because of the way they are configured from the water sources, commission water pipes in the summer send river water to mostly western areas of the Rogue Valley and spring water to mostly eastern areas of the valley. The spring and river water is blended, however, as it flows to customers in Medford, Central Point, Jacksonville, Eagle Point, White City and Phoenix. But last month, hundreds of people called to complain of a musty taste and odor. Record-high algae levels in the Rogue River caused it, but the water remained clean and safe to drink. Twice on hot August days, levels of geosmin - the byproduct of blue-green algae that's responsible for the musty taste and odor - climbed to 62 nanograms per liter of raw water, up from an average of 5 to 10 nanograms most summers, said Bob Noelle, water quality superintendent. Even after the water was treated, recorded geosmin levels were 35 nanograms at the treatment plant and 11 nanograms at Central Point's City Hall, much higher than what the treatment plant can handle, said James Stockton, water plant supervisor. "We've always taken pride in how our water tasted," said Ed Olson, Medford Water Commission manager. "We were humbled by our inability to get rid of the taste and odor problems caused by geosmin." Just as geosmin levels have been high this summer - one of the driest on record - levels were high in 1999, 1997, also dry summers, and in 1978, the year Lost Creek Lake was filled. The submerged tree stumps and soils likely contributed to algae blooms, Noelle said. "We generally felt it was not a one-time event," Olson said. "Our response was how do we handle it to satisfy our customers." The Medford Water Commission, which is debt-free, will pay for the $5.6 million ozone system through a construction reserve account. The "savings account" will be replenished by this year's increase in water rates, which are $120 a year for basic services. Ozone has long been used in the bottled water industry as a disinfectant, partly because it's so effective and partly to please consumers who don't like the taste of chlorine in water. Crystal Geyser's water bottling plant in Weed, Calif., for example, injects ozone in its spring water captured at the base of Mount Shasta. But public water systems can't rely solely on ozone because only chlorine stays in the water long enough to keep it clean as it travels through pipes and distribution systems, said Tom Charbonneau, regional engineer for the state's drinking water program. While cities such as Reedsport or Las Vegas use ozone as a disinfectant, Medford's primary reason for injecting ozone is to improve taste. "The ozone is doing the work, whether it's attaching itself to a mineral (such as iron) or destroying the taste and odor compounds or destroying organisms that cause illnesses," Noelle said. "Ozone is a powerful oxidant." Reach reporter Melissa Martin at 776-4497, or e-mail [email protected] Mail Tribune Home | Ottaway Newspapers, Inc. | Dow Jones & Co., Inc. | Privacy | Contact Us Copyright � 2001 Mail Tribune, Inc.