Mount Ida says heavy rains led to wastewater release

An estimated 3.8 million gallons of wastewater released into the Lake Ouachita watershed in March from a holding pond at Mount Ida’s wastewater treatment plant kept the pond’s levee from collapsing, the plant operator says.

February’s heavy rains caused the south fork of the Ouachita River to leave its banks and compromise the outside of the levee on the north side of the plant’s equalization basin, which plant operator James Stanley said was receiving untreated wastewater when the plant released some of the pond’s storage. The National Weather Service’s Mount Ida station reported 14.33 inches of rain during the final nine days of February, more than three times the average rainfall for the month.

The river is the permitted receiving waters for wastewater that’s been treated at the plant. According to an Arkansas Department of Environmental Quality March 16 inspection report, the plant reported the release March 5, after heavy rains had caused a “major flood event” on the river.

“This, in turn, had caused a significant portion of the outside levee wall to slough off,” the report said. “With the high flows entering the EQ basin during that time, the facility was concerned with water overtopping the weakened portion of the levee and the potential for it to give way.

“The facility decided to breach the EQ basin levee near the northwest corner of the basin and allow a slow drawdown of the basin.”

Stanley estimated 3.8 million gallons were released into the river over a week, lowering the level of the pond by 15 inches and allowing heavy equipment to reinforce the inside of the levee with fill dirt. Stanley said the levee has been stabilized. ADEQ spokes-

woman Kelly Robinson said the reinforcement work was a stopgap measure, and the plant will be required to submit a plan for more permanent repairs.

“It was almost at the top,” Stanley said. “It had rained every day. It was so wet, you couldn’t get a backhoe up there because we were afraid it would collapse. We let some water out so we could get to the top of the levee to do some work on it. We didn’t know if it was going to collapse in the next few hours or days.”

When that concern was reported to ADEQ , its Office of Water Quality referred the plant to the provision in its discharge permit that allows it to release untreated wastewater if “loss of life, personal injury or severe property damage” cannot be prevented otherwise. According to the permit, a release under those circumstances is protected from enforcement action.

Stanley said one of three pumps that feed the plant was diverting flow to the equalization basin during the February rain event. Rain seeping into the collection system had increased the plant’s input, requiring extra flow to be held in the equalization basin until it could be treated.

“I had no choice but to run one pump into (the equalization basin),” he said. “You can’t run three pumps through the plant. It will overflow, because the pipes aren’t big enough.”

Stanley said rainwater that collected in the basin diluted what was released into the river. According to data provided by ADEQ , samples of the release collected and analyzed by the third-party contractor the plant uses to submit its discharge monitoring reports to the state showed biochemical oxygen demand at almost four times the permitted amount.

BOD is a measurement of water pollution, showing how much oxygen microorganisms are using to consume organic matter in the water. The sample’s pH level was also over the limit but total suspended solids and E. coli were well below permitted levels.

The plant is one of more than a dozen wastewater treatment facilities ADEQ has permitted to discharge into the Lake Ouachita watershed or directly into the lake, according to information provided by ADEQ. The plant’s permit lists its design flow at 200,000 gallons a day, giving it the most capacity of all the facilities permitted to use the watershed as receiving waters.

Stanley said the plant can process as much as 600,000 gallons a day.

Six of the permitted facilities treat wastewater from U.S. Army Corps of Engineers recreational areas. The Mount Ida plant is the only facility permitted to discharge treated municipal wastewater into the watershed. The combined design flow of all the permitted facilities is about 500,000 gallons a day.