A cutting edge wastewater treatment process may save Rockdale Water Resources hundreds of thousands in electricity costs and sludge handling costs, according to RWR reports.
At the Oct. 27 Water and Sewerage Authority meeting, members were briefed on the CATABOL process, a system patented by a Georgia Tech researcher who is an acquaintance of an RWR employee.
The system, which has been implemented in several industrial plants and one municipal plant at the city of Cartersville, could potentially save Rockdale about 20 percent in overall electricity costs and about 40 percent in operating costs, said Rockdale Water Resources Director Dwight Wicks.
The new process would reduce electricity costs by not needing as much pumping for aeration and the process itself produces less solid sludge, reducing the need to take it out and put it into the landfill. Currently, the county spends about $600,000 in sludge costs.
The Quigg Branch Wastewater Treatment Facility is permitted at 4.5 milion gallons per day. It was originally designed to to handle 6 MGD, but because of excess solids loading, its permitting was reduced to 4.5 MGD and it is looking to increase its capacity another 2 MGD.
In a comparison presented at the meeting of the modifications required for 2 MGD increase with the CATABOL process and for other processes that RWR had looked into previously, the CATABOL modifications would cost about $4.3 million, the JJG modifications would cost about $15.2 million, and the Brown and Caldwell modifications would cost about $12.5 million.
Wicks said their engineers had been looking at the process for the last four months and had gone over to visit the Cartersville plant. "EPD have agreed to sign onto it. ESG has a number of questions. They told me when they went there they were expecting it to be a snake oil remedy. But they put together their list of questions and they came away very satisfied."
Authority members recently visited Cartersville’s wastewater treatment plant, which serves about 33,000 residents, handles several industries including Anhueser-Busch, treats about 8 million gallons per day and has the capability to treat up to 15 million gallons per day.
Jim Stafford, director of the city of Cartersville’s wastewater treatment facility, said the new system, which was implemented there more than a year ago, has saved the city 33 percent in operating costs. The majority of the savings has been in reducing the amount of electricity needed for aeration pumping.
The key to the new system is introducing the anaerobic bacteria up front, before the aerobic portion of the process, and then keeping them in a separate storage tank.
"These anaerobic bacteria digest stuff very slowly," explained Stafford. The CATABOL process takes some of the anaerobic bugs out of the loop and allows them to digest in a separate tank until they are "hungry" again and then are put into the wastewater again. "So you’re always feeding hungry bacteria and taking out the ones that are fat and sleepy."
The beauty to the system is that it doesn’t introduce any new organisms or technology, said Stafford.
"We haven’t put anything in the plant that hasn’t been in the industry for 100 years. We’ve rearranged the way the plant is set up." He said the wastewater treatment industry in general is slow to adapt new methods.
Stafford said the plant was currently looking at trying to capture the methane generated by the anaerobic bacteria to generate electricity that could be used for running the plant.