Process approved for $15M plant expansion

Wednesday, October 22, 2008

Another step has been taken toward increasing the capacity of Lewisburg's sewage treatment plant with the approval of a sludge processing plan that would have the stuff transformed into fertilizer.

Treatment plant expansion may cost $15 million and include a holding tank built on land recently bought by the city. The tank will regulate flow to the plant that will still have two end products: liquid effluent that's drained away; and bio-solids.

"Our consulting engineer developed a sludge handling plan," City Water and Wastewater Department Superintendent Larry Jones said Friday of a system selected after the utility board inspected systems in Pulaski and Shelbyville.

Utility Board Chairman Pepper Biggers said the Board on Thursday authorized use of a process that will result in a "product usable by farmers." It will eliminate the spreading of sludge on open fields that are owned and rented by the utility.

"Shelbyville hauls theirs ... to the landfill here," Biggers said. "Pulaski makes it available to farmers for fertilizer."

The difference is that the latter is disinfected and, when mixed with mulch, it's not much different from potting soil.

"We'll integrate this project into the expansion of the plant," Jones said.

Lewisburg's 22-year-old sewage treatment plant can now fully process three million gallons per day and partially treat up to 10 MGD when conditions require. Such operations are not rare.

During extended periods of rain, leaky pipes allow ground water to infiltrate the collection system, thereby adding volume for treatment.

Plant expansion will allow full treatment of up to six MGD and the holding tank would regulate the flow so it wouldn't overwhelm treatment capacity.

The proposed, round concrete holding tank is anticipated at some 15 feet deep with some of it underground, Jones said. Its diameter is to be 165 feet.

"We'll be buying eight acres, more or less, of the old Murray Farm property," Jones said.

Lewisburg' Water and Wastewater Department was encouraged by the Tennessee Department of Environment and Conservation to expand and improve its wastewater plant, Jones said.

Meanwhile, the city has continued to apply for, receive and spend federal funds to rehabilitate sewers to reduce infiltration. Such efforts are always multi-million dollar projects.