The agency wants to use ultraviolet light rather than liquid chlorine bleach to kill bacteria in the sewage it treats.
"We think it's a better long-term solution, better than chlorine bleach with less chemical reaction," David Hawes, RWRA's executive director said recently.
The agency has been discussing that plan for four years.
Hawes said RWRA hopes to get the $3.3 million loan at an interest rate between 1.75 percent and 2.75 percent.
And it's hoping to qualify for money through the city's plan to create a tax increment financing district for the planned $200 million Gateway Commons commercial-residential development just south of the David Hawes Wastewater Plant on Pleasant Valley Road.
Since that plant will be inside the TIF district, Hawes said he's hoping RWRA can qualify for tax funds for the ultraviolet light system.
"We have to replace the 1985 wiring at this plant," he said of the treatment plant on Pleasant Valley Road. "It's substandard. We should know by August or September if we'll qualify."
Most of the expense — probably $2 million — would be at the Pleasant Valley Road plant, he said.
The rest will be used to install the same system at the Max Rhoads Treatment Plant on Ewing Road, which serves the west side of the city.
The Pleasant Valley Road plant, which the RWRA board recently renamed in honor of Hawes, who is retiring in August, will provide sewer service to the Gateway Commons property, Hawes said.
"Probably the best-case scenario would be to start construction on the ultraviolet light system in mid-2016," he said. "Worst-case would probably be late 2016."
RWRA began talking about the ultraviolet light system in 2011 when it was looking at a number of options for treating sewage.
"There are various treatments to kill bacteria," Hawes said at the time. "We currently use liquid chlorine bleach. In Europe, they use peracetic acid, a combination of peroxide and vinegar. It's more environmentally friendly than chlorine. It's a one-step process. Now, we have a two-step process because we have to treat the chlorine too."
He said the agency has to "get rid of anything that would pollute the environment."
RWRA was also considering using ultraviolet light to kill bacteria, Hawes said in 2011.
"You spread the effluent over a large area and use ultraviolet light to kill the bacteria," Hawes said.
"There's a lot of capital construction costs with that," he said. "It's probably not big on our list right now."
But early last year, RWRA began settling on ultraviolet light as the best plan for the future.
"We think it will save money in the long run, because we won't have to continue buying chemicals," Hawes said then.
Ultraviolet light has also been used in Europe for nearly a century to disinfect municipal water supplies, he said.
It's becoming popular for wastewater disinfection in this country, because it adds nothing to the sewage like chemicals do, Hawes said.
©2015 the Messenger-Inquirer (Owensboro, Ky.) Distributed by Tribune Content Agency, LLC
