Ozone used for bacterial reduction in drinking water

City of Oregon, OH turns to ozone to treat drinking water.  According to city officials ozone was a better technology for bacteria reduction.

 

Ozone helps protect the earth’s surface from harmful ultraviolet rays, but Oregon is using it to combat something else.

In an effort to ensure the safest drinking water possible, the city’s water treatment plant has gone ahead with plans to use ozone to eliminate harmful bacteria, including cyanobacteria that produce microcystin.

“Ozone treatment is really the emerging, best practice to deal with surface water,” Oregon city administrator Michael Beazley said.

Oregon was not affected by Toledo’s water ban in 2014, but the crisis was an eye-opener, prompting research into this new technology.

The city’s water intake is in Lake Erie, but it is separate from Toledo’s. When lake water reaches the Oregon’s treatment plant, ozone combines with electricity to break up any organic contaminants in the water into smaller pieces. What’s left goes through biological filtration. The system kills algae-related toxins in about eight-tenths of a second.

“Once you get ozone added into the treatment, you’re going to eliminate any chance of microcystin getting into the tap water,” said  Doug Wagner, superintendent of water treatment. “[The algae problem] isn’t going to go away, so we’re going to hit it head-on.”

The plant ran a pilot program from July to November. During the program, crews used the ozonation process to treat four gallons of water per minute, sent it through the contact chamber, and put it in a biological filter.

“It was like a microplant,” Mr. Wagner said. “We had four columns that had different filter profiles in each one to put the ozonated water through to see which one would grow the best bacteria that would consume the organics in the water.”

The new system, which is expected to be in place by the 2017 algae season, should lower the amount of chlorine used in drinking water, officials said. Ozone is a better disinfectant and produces fewer disinfection byproducts, known as trihalomethanes. It also eliminates a higher number of trace organic compounds, officials said.

“By reducing the amount of chlorine we use, we end up with water that is safer, more easily treated, has a better taste to it, and end up without some of the by-products you end up with using chlorine treatment,” Mr. Beazley said.

After the ozone disinfects the water, it turns back into oxygen. All water leaving the plant will be ozone-free.

The entire project is expected to cost about $14 million, funded mostly by a zero-interest loan of about $750,000 a year for 20 years from the Ohio Environmental Protection Agency’s Water Supply Resolving Loan Account. The city also secured a $1.4 million grant from the Ohio Public Works Commission.

Oregon’s water rates will increase slightly over a period of time. The average customer will pay about $2 to $3 more a month, city officials said.

Mr. Beazley said bids for construction submitted in December  are being reviewed, and a contract should be awarded in the next few weeks.
Read more at http://www.toledoblade.com/local/2016/01/11/Oregon-turns-to-ozone-to-treat-its-water.html#oqQ5mUqG7bBgWqit.99

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