SBR system will be 'cat's meow'

Completion of plans for the new wastewater system for Eureka Springs are within 60 days of being ready to send to the Arkansas Department of Environmental Quality (ADEQ) for review and approval so construction can start late in the fall.

Consulting engineer Ron Tracy told an audience of six persons Thursday evening he is working on the preliminary drawings. He needs to get equipment and piping size specifications before he can complete the plans.

He estimated it would take ADEQ approximately 30 days to review and approve them.

With that timeline, actual construction could start in November.

Public Works Director Robert Forrest has estimated it will take a year to get the plant built, operators trained and into operation.

He has estimated the cost of the new plant at $2.2 million or $2.20 per gallon of wastewater.

Tracy said exact costs would not be known until bids were taken on the site work and equipment.

A large portion of the funding is already on hand, provided by two bond issues set up for improvements at the treatment plant and work on the city's collection system.

Mayor Kathy Harrison said Monday the city is expecting to save approximately $75,000 a year in operation and maintenance. The savings, and water bill revenue, will be used for the rest of the construction expense.

Forrest's estimate includes engineering, drawing of the plans, plant demolition and construction.

He was careful to explain that the existing plant is able to treat wastewater and has been in compliance with ADEQ limits in two of the last four tests.

"The plant has not worked properly in 20 years, and isn't today," he said, "but we are discharging cleaner water than before and meeting our limits. The people of Eureka Springs deserve a plant that works."

He said the city can "limp along with what we are doing as long as we keep ADEQ informed about what we are doing. They are working with us. If we stop, then they will come in and start fining us for not being in compliance."

Demolition of the old sludge drying beds, the trickling filter tank and the anaerobic digester, with ADEQ permission, is underway.

When the first opening was made in the concrete side of the trickling filter tank in June, Forrest thought the tank might be salvageable and used to hold overflow rain water.

Some of the design of the plant has been moved within the property available alongside Highway 23 north.

"We discovered part of the plant was actually built in the highway right-of-way," Forrest said. "We have had to shift things over about 20 feet."

Mayor Kathy Harrison said no additional land will have to be purchased for the new plant. In fact, the existing property will have room for expansion of the new system when it is needed.

A Sequential Batch Reactor (SBR) system will be the method for treating wastewater in the new plant.

Chad Cooley, engineer with Environmental Technical Sales, Inc., of Germantown, Tenn., said, "You can get a lot of treatment in a compact area with an SBR system. It is a superior process."

He explained the treatment process from the wastewater arriving at the plant going through a screening and aeration (forcing air into the water) basin then to a clarifier/settling basin.

Once the water has settled, from 30 to 45 minutes, depending on the timed cycle, the water in the top of the tank is drained off and put through a disinfection system of ultraviolet lighting before it is given another shot of oxygen prior to being discharged into the creek.

The new plant is to be built with two basins providing a daily capacity of treating one million gallons of wastewater per day (mgd) with a capacity treatment of three mgd.

Adding a third basin sometime in the future, would put the daily capacity at two mgd.

Forrest said the daily treatment right now is 250,000 gallons per day. On "wet days," the flow goes up to 500,000. The worst day he has seen since his hiring in March is 1.1 mgd.

"With the new plant, we will be getting four times the capacity for what our normal daily flow is now," said Harrison.

"This is the way to go," Cooley repeated. "It is more efficient, takes less space and is less expensive to operate. It's the cat's meow."

In his opening comments, Forrest said the current system, which uses a methanol treatment, is the only one of its type in Arkansas, the surrounding states, and, possibly, the country.

"They uses this kind of system in third world countries," he said.