Biosolids Anaerobic Digestion at Akron, OH: KB BioEnergy

Biosolids Anaerobic Digestion at Akron, OH

KB BioEnergy’s anaerobic digester was first constructed in 2007 to process dried biosolids from the city’s municipal treatment plant. An expansion of the facility in 2013 allows the digester to process 100% of the sewage sludge from the wastewater treatment facility and create additional renewable energy. The system was built as a joint venture between the City of Akron and KB BioEnergy.

KB BioEnergy Digester_BIOFerm Energy Systems_COCCUS_EUCO_Complete Mix Digester_Plug Flow DigesterPlant Technology and Process

The plant consists of three EUCO® plug flow digesters, one All-in-One (AIO) technical container, three COCCUS® complete mix digesters, and three additional 600 kW MWM engines. The biosolids are added into the EUCO® where the first stage of anaerobic digestion, hydrolysis, takes place. From EUCO®, the feedstock is pumped into COCCUS® where the anaerobic digestion process is completed. The effluent is separated into a liquid phase and a solid phase. The solid phase is further composted.


The plant is designed to handle up to 15,000 tons of dry biosolids per year. The biosolids have a maximum solids content of 15% total solids.

Power Production—Initial Plant (2007)

330 kWelcontinuous power engine (combined heat and power unit, CHP)

  • 330 kW electric capacity
  • 405 kW thermal capacity

Power Production—Plant Expansion (2013)

1.2 MWelcontinuous power engine (combined heat and power unit, CHP)

  •  1.2 MW electric capacity
  •  1.3 MW thermal capacity