Kenosha Waste Water Treatment Plant Energy Optimized Resource Recovery Project

In an effort to combat ever rising natural gas and electric utility costs and landfill disposal fees, the Kenosha Water Utility (KWU) began to explore emerging technologies as a means of becoming more energy independent while also reducing the volume of biosolids in need of disposal. The results of our investigation led to the awarding of a contract for an energy optimized resource recovery system that would overhaul the biosolids portion of our wastewater treatment plant. The new system would consist of high solids anaerobic digestion, mechanical hydraulic mixing within our anaerobic digesters, biogas conditioning, primary sludge thickening, waste activated sludge (WAS) thickening, thermo-chemical hydrolysis, centrifuge dewatering, sludge drying, and electrical and thermal production using co-generation. The above-mentioned system was implemented to increase the production of biogas, utilize the biogas to produce electricity to reduce our dependence on our local utility and offset peak energy pricing, increase the drying of biosolids so as to produce 90% dry solids, reduce the volume and cost of biosolids landfilled, produce a high quality biosolid that met the criteria for Class A biosolids, and recover and utilize the waste heat as the main thermal energy supply for the facility. All of this was to be accomplished while also maintaining existing effluent quality, sustaining ambient noise, odor and particulate levels and providing a payback period of eight years or less.