ICM/PBS personnel provided design, fabrication, technical development, start-up and training services for the implementation of the anaerobic Bio-Methanation system at the VeraSun Energy Ethanol Plant in Aurora, SD.  The turnkey Bio-Methanator plant is a skid–mounted unit designed and built by ICM-Phoenix for VeraSun Energy, LLC, which is a 100 MM GPY plant, designed by ICM, Inc. and built by Fagen, Inc. The Bio-Methanator is integral with overall plant design for water re-use.

      The ICM/PBS Bio-Methanator system consists of quadruple upflow expanded-bed, 30,000-gal bio-reactors, capable of removing up to 4,000 pounds per day of COD (Chemical Oxygen Demand) each, from evaporator condensate. The bio-reactors are located out-of-doors, while all control and sampling units are skid-mounted and located inside the plant's process building.  The two-level control skid was used as a basic structure to provide an add-on building to the existing mechanical building, by adding metal skin and insulation to the outside of the skid.

      The entire anaerobic system was pre-fabricated at the ICM shop in Colwich and shipped to the site in Aurora for installation, which required less than two weeks. The bio-reactors are pre-molded FRP including all internals.

      The unit was installed in August 2003, during plant construction, and started up in November 2003. Start-up and personnel training were completed in ten days and the plant was turned over to operating personnel shortly thereafter. The Bio-Methanator has operated successfully since start-up averaging over 90% COD reduction in a mixture of evaporator condensate, thin stillage and waste CIP, and consistently produces effluent waters suitable for re-use in the plant cook system.

     Daily operating costs are extremely low, requiring only one to two hours per day of operator and lab time along with small amounts of nutrient chemicals and less than 27 operating horsepower.  Bio-gas produced by the system is piped to the plant's DDGS dryer providing an energy return of approximately $62,000 per year, which more than pays operating costs of the Bio-Methanator.