A recent discharge at Richmond Hill’s Sterling Creek wastewater treatment plant was termed a “major spill,” but city and state officials claim it is no cause for alarm.
A discharge of treated water into Elbow Swamp on May 28 exceeded the plant’s permitted limit for biochemical oxygen demand, or BOD, Richmond Hill Public Works Director Charles Heino.
Test results received Friday showed the effluent at 31 milligrams of BOD per liter of water, higher than the 25 mg/L allowed for the plant at this time of year. BOD is the amount of dissolved oxygen microorganisms consume in breaking down wastewater.
That classified as a “major spill” for reporting purposes to the Environmental Protection Division. However, the city and EPD both clarified that no sewage actually spilled.
“Technically, it isn’t a spill. Basically it’s an exceedance of permit limits,” said Bruce Foisy, the district manager for EPD’s Coastal District.
The water released was “in fact, fully treated water, with just an elevated BOD,” Heino said. The potential danger is “none whatsoever,” he added.
“There’s no concern of fish kills or anything of that nature,” Heino said. “If it got high — three or four times our limit — it would result in a fish kill. But we’re so far away from that level, it’s not an issue.”
City officials have not been notified of a possible fine from EPD, Heino said. The EPD is in the midst of determining whether a penalty is merited, according to Foisy.
“We’ve got it under investigation,” he said.
The city posted a sign at the Sterling Creek site about the elevated BOD level and another sign at a location downstream, Heino said. Elbow Swamp runs to Sterling Creek and eventually to the Ogeechee River.
No further action was taken by city officials. The Sterling Creek plant’s “natural land-application process and subsequent manmade wetlands do not allow us to mitigate instances of higher BOD levels currently,” according to a city news release.
The Richmond Hill plant is a constructed wetlands wastewater treatment facility, a more cost-effective and environmentally friendly option than a mechanical plant. The manmade sewage lagoons imitate natural wetlands by filtering sewage with native plants, microorganisms and other natural processes.
As the weather and environmental factors change throughout the year, so do the permissible BOD limits for the plant.
“If this was April, it wouldn’t even be a violation,” Heino said.
The city is nearing completion of a newwater reclamation facility at Sterling Creek. The approximately $24 million plant is “designed to prevent and mitigate any further violations of this type,” the press release states.
“The reason we’re building a new plant is because we have so little control over these parameters,” Heino said. “We’re really at the mercy of our environment.”
Set to open this fall, the new water treatment plant isthe single largest expenditure in the city’s history. It is being paid for by increases in water and sewer rates approved by City Council in November.
The city previously has paid fines for discharge permit violations at the Sterling Creek treatment plant.In 2008, the city settled with the EPD and signed a consent order to keep the facility operating.
Because of those repeated problems with spills, the EPD mandated that a new plant be built. The new one will be able to meet “more stringent requirements,” a Foisy.
“That’s something they’re required to do, and they’re doing it,” he said.