A cutting edge wastewater treatment system that promised to expand Rockdale’s sewage capacity and save in operating costs is getting a hard look after operators raised questions about its feasibility.
About $340,000 has been spent in the design phase of the CATABOL system project so far, out of about $4.5 million slated for the project, according to Rockdale Water Resources Director Dwight Wicks. About $3 million of the funds are left over from a 2005 bond refinancing. The design has been completed but construction has not started as members of RWR, operators ESG, designer Boris Khudenko, and other parties discuss issues raised, said Wicks.
“The process works,” said Wicks. “There’s some questions we’ve got to get resolved. RWR as well as ESG as well as Boris are all confident the process does work.”
Wicks declined to describe some of the questions raised, citing the patented and proprietary nature of the system, developed by Boris Khudenko, a Georgia Tech researcher and associate of an RWR employee.
One other municipality in Georgia operates the CATABOL system – Cartersville. However, local plant operators learned the city recently stopped using it for certain periods.
Wicks said a similar system called Cannibal, owned by the Siemens company, is being used in locations across the country such as Peru, Indiana and Healdsburg, Calif.
A few questions had also been raised back in 2009 and 2010 when the CATABOL system was first proposed. In a 2009 presentation given by ESG to the Water and Sewerage Authority, some concerns included the fact that the system had been established in only one other municipal location in Georgia - Cartersville - which was a less restrictive plant than Quigg. The system would also require trial and error operationally and require a close partnership between RWR, ESG and the designer.
According to Authority Chair Elaine Nash, another concern was that if the system did not work, Quigg would be required to return to its current system, and Rockdale might not have the funds to do that.
“When we go on to expand Quigg, we don’t need an experimental process. We can’t afford to be a guinea pig,” said Nash.
Some of the urgency of putting the system in place has abated giving the parties more time to take a second look.
When the CATABOL system was proposed in 2009, Rockdale was bumping up against its maximum sewage capacity and feeling the squeeze. Quigg is permitted up to 6 MGD, but was topping out its ability to process at 5.5 MGD due to the heavy concentration of effluent coming in.
The CATABOL system was described as potentially increasing the capacity by 2 million gallons per day at Quigg, Rockdale’s main wastewater treatment plant, in addition to saving about 20 percent in overall electricity costs and about 40 percent in operating costs. However, a number of changes have brought the down the amount being processed to about 3.8 to 4.2 MGD.
Nash said one significant change the drop in the number of septage haulers after septage rates were increased and a system put in place to better track the septage loads. The waste from septic tanks is about 40 times more concentrated than normal wastewater, she pointed out.
However, Wicks said septage dumping accounted for about 0.016 MGD of the capacity that was being taken up.
Wicks said it was a combination of things that accounted for the high usage and that the reduction in septage haulers was just one part of it.
“One of the things that increased it was the use of water saving appliances,” said Wicks. “Low flow toilets, low flow washing machines, low flow dishwashers… It’s coming in more concentrated.”
“That and the fact we found out we were getting quite a bit from Pratt… more than we thought.”
Procedures were changed with the Pratt treatment facility that RWR operates to take out more of the solids and the septage rates were increased, dramatically reducing the number of loads septage loads brought to RWR.
Developers that had also reserved sewage capacity for buildings that never materialized also started returning some of the reserved capacity.
Rockdale also initially faced a deadline of 2015 to refit three of its smaller plants on the south side – Snapping Shoals, Scott Creek, and Honey Creek – or to shut them down. The three small plants represent about 0.75 MGD capacity, Wicks said. However, Rockdale is in discussions with the EPD about the plants, according to Wicks.
The CATABOL system also looked like it would be less expensive than building a whole new plant or expanding Quigg. Wicks said the general rule of thumb estimate is that it costs about $10 million to gain an additional 1 MGD capacity.
Nash said that when the Authority first looked at the CATABOL procedures, the members had only been in place for five months. If they were looking at it now, she would not have been so quick to consider it, she said.
“I just think that plant is too important to Rockdale County and to major economic development. We can’t afford to be experimental.”