Kenosha’s Energy-Optimized Resource Recovery System

The intent of this paper is to convey the story behind Kenosha Water Utility’s (KWU’s) quest to become less energy reliant and more environmentally sustainable. Faced with an aging treatment plant in need of anaerobic digester repairs and a valuable biogas resource that was underused, KWU issued a Request for Proposals (RFP) for the design, installation, start-up and commissioning of an energy-optimized resource recovery system.The goals of the project were to: increase the generation of methane gas from the biosolids; generate greater than 500 kW of continuous power from the methane gas to run the new process and send usable power back to the existing plant power network; use the electric and thermal energies generated to dry the biosolids to 90% dry solids and produce Class A biosolids, reducing the volume and cost of biosolids disposal; maintain existing effluent quality of the plant; maintain or reduce the ambient noise, odor, and particulate levels beyond the waste water treatment plant; obtain a performance warranty for the system; and, provide a payback period of 8 years or less.This paper reviews the design/build construction phase of the project and the following one-year optimization phase of the process. Preliminary process results are presented and lessons learned during the project are described.