LITTLE ROCK — Since opening in July, a Little Rock Wastewater peak flow attenuation facility has prevented 138.1 million gallons of wastewater from overflowing into the environment, the agency’s engineering supervisor reported Friday.
“We’re very pleased with it,” said John Holloway. “We had a few glitches during the first two rain events but got those ironed out. It has done what was planned for it to do.”
The utility is required to reduce sewer overflows because of a settlement reached with the Sierra Club of Arkansas. The $33 million project, called the Peak Flow Attenuation Facility, is the largest to be completed under the utility’s $338 million capital-improvements plan.
The larger of the facility’s two basins is about the size of a football field and can hold up to 20 million gallons of diluted wastewater; the smaller basin will hold about 10 million gallons.
The facility, in an industrial area at 5200 Scott Hamilton Drive, is fully automated, Holloway said.
“Our first time to test it was during the first rain event in September,” he said. “The last few rain events, it’s been working perfectly.”
Joe Schaffner, a spokesman for the utility, ex-plained that water will flow from the sewer lines into the smaller basin after being fed through a “grit tank,” which will catch any sediment in the water. Once the smaller basin fills, the 20-million gallon tank will open to accommodate the surge.
Only about 2 percent of the liquid in the basins would be sewage and the rest would be rainwater, Schaffner said.
“The project is designed to handle a storm where up to five inches of rain would fall within 48 hours,” Schaffner said. He estimated that the facility would be used 10 to 15 times per year.
Since July, the facility has been used six times, collecting from a low of 12.3 million gallons of overflow on Oct. 14 to highs of 30 million gallons on Sept. 15, Oct. 9 and Oct. 29.
“The autumn months were a very rainy, stormy time for Arkansas,” Schaffner said. “Gov. Mike Beebe declared 37 counties, including Pulaski County, disaster areas.” In addition to a soggy autumn, the state was regularly drenched from late April until mid-May.
Before the facility opened, capacity overflows, those caused by heavy rain, were an erratic problem for the utility. In 2006, there were 154 such overflows compared with 113 in 2007, 325 in 2008 and 155 through May of this year, according to a report from Little Rock Wastewater.
Such overflows, where heavy rain sometimes forced raw sewage to gush out of manholes, prompted the Sierra Club to sue the utility in 2000. A federal settlement was reached in 2002.
Schaffner said every enhancement to the city’s sewer system, which serves 68,000 customers, puts the utility closer to its goal of protecting public health.
“As Little Rock Wastewater continues to undertake projects to improve our collection system and treatment process, we know that we are better off today than yesterday because of projects like the peak flow attenuation basin,” he said.
Arkansas, Pages 9 on 12/21/2009