Until 2013, KB Compost Services was under contract with the city of Akron, Ohio, to operate the Akron compost plant. In 2013, the plant was transformed into a state-of-the-art anaerobic digestion operation that processes 100% of Akron’s sewage sludge from the Akron Water Reclamation Facility. KB Compost Services then changed its name to KB BioEnergy to reflect the change in process. The final dried biosolids are used as fertilizer and blended into products by KB BioEnergy’s parent company Kurtz Bros.
KB BioEnergy continues to be under contract to operate the now named Akron Renewable Energy Facility, which converts biosolids from the city’s WRF into biogas. The biogas is then consumed by two 600 kW combined heat and power units (CHPs). Roughly 43% of the energy produced is in the form of heat and 44% is electricity totaling about 87% efficiency. The power generated by the on-site CHPs is consumed at the WRF and the REF.
Even in its composting days, Vogelsang had been a supplier of pumps and solids reduction equipment to the plant. When the new anaerobic digestion facility was built, Vogelsang was the perfect fit since rotary lobe pumps are ideal for pumping sludge with 3 to 18% solids, including RAS, WAS and digested sludge.
Vogelsang pumps are used throughout the plant to move sludge into, between and out of digesters with a capacity of 2 million gallons. The sludge is heated to about 95 degrees F and remains in the tanks for approximately 30 days. Through anaerobic digestion, bacteria break down the sewage sludge. As the bacteria multiply, they consume part of the sludge and produce a methane-rich, burnable gas that is 60%-65% methane, 30%-35% carbon dioxide and 5% other gases. In comparison, natural gas is about 90% methane…