It was not the glamorous event that often accompanies a ribbon-cutting. But the snip of the scissors Aug. 12 at the new Peachtree City Biosolids Treatment Facility operated by the city’s Water and Sewerage Authority (WASA) is expected to bring a more cost-effective and environmentally responsible way to deal with the city’s sewage sludge. The facility and its high-temperature drying unit from AGL Energy Services is fueled by natural gas.
With a top temperature of approximately 1,200 degrees that exceeds federal Environmental Protection Agency standards, the high-temperature drying unit transforms sewage sludge to Class A biosolids material within 20 minutes of process initiation. The result is a product from which more than 99 percent of pathogens have been burned off using a natural gas-fired drying unit. The processed material is subsequently sold as a soil amendment or fertilizer.
All gases from the sludge treatment are routed through an air-filtration system and thermal oxidizer to ensure particulate removal and the destruction of more than 99 percent of the volatile organic compounds present in the sludge, thereby allowing only cleaner exhaust gas, essentially water vapor, to be released into the atmosphere, according to AGL.
The system is beneficial in terms of the end-volume of waste produced. Every five pounds of sludge entering the system leaves the facility as one pound of Class A biosolids, officials said.
The new facility also comes with a cost component that is expected to save money. The former cost of $75 per ton in tipping fees plus transportation costs for shipping what was then a Class B sludge containing pathogens to a regional landfill that would accept the product was decreased a few years ago when the city’s biosolids product was shipped to Plains for composting.
The cost with the new AGL unit decreases costs even further to the $40-range, officials said. Those saving are significant given that Peachtree City produces approximately 125 tons of sewage sludge per week.
“The new biosolids facility not only minimizes our everyday operational costs, but more importantly, allows us to significantly reduce our carbon footprint by taking trucks off the road and converting waste into a reusable byproduct,” said PCWASA General Manager Stephen Hogan.
Both Hogan and AGL officials noted that until recently, landfill disposal was the preferred method for dealing with sludge, the byproduct of domestic and commercial sewage and wastewater treatment. Environmental and health concerns associated with contaminated storm water runoff, air pollution and contaminants have prompted many landfills to close their doors to sludge. Subsequently, the rising disposal fees and transportation costs have prompted many municipalities to seek more efficient and environmentally friendly alternatives, they said.
“At AGL Resources, we are committed to finding sustainable solutions to reduce the carbon footprint in the communities we serve,” said Hank Linginfelter, AGL Executive Vice President for Utility Operations. “With this facility, we are proud to use clean-burning natural gas to provide Peachtree City Water and Sewerage with an environmentally friendly and cost-effective method for transforming its sludge into a useful agricultural product.”
