Waste-to-Energy Wastewater treatment system for Pearl Valley Cheese

Siemens (USA) has been awarded the contract to provide process equipment, design and start-up services for a wastewater treatment system at Pearl Valley Cheese, Inc. production facility in Fresno, Ohio. The system will be designed to convert waste material generated during cheese production into reusable biogas generated in the wastewater treatment process. This renewable energy approach allows Pearl Valley Cheese to receive a state funding grant, and reduces the amount of natural gas required to operate the facility’s boilers, which are used for providing steam for the cooking, cleaning and pasteurising process. The 50,000-gallon-per-day (GPD) (189,000 LPD) system, which will be able to handle a variety of waste streams and still meet effluent requirements, is scheduled for start up in the summer of 2010.

Siemens will provide an influent screen, neutralisation equipment, anaerobic contact process (AnCP) reactor, an Agar moving bed reactor (MBBR) for aerobic polishing and a Dystor Biogas Storage system. Pearl Valley Cheese considered other wastewater treatment technologies, but chose Siemens based on its experience, as well as system cost and installation time.

The AnCP is a low-rate anaerobic process that incorporates an anaerobic bioreactor and a clarification step in series. The methane gas by-product of anaerobic treatment, with a heat value of approximately 650 BTU/FT2, offers a return on the capital investment in the form of “green energy”. The AnCP is used in conjunction with the Dystor Biogas Storage system, an engineered dual membrane storage technology that provides flexibility in biogas availability to meet the plant’s production demands for energy. The DAF system removes suspended solids, fats/oil/grease and other insoluble materials, and typically produces sludge concentrations several times that of conventional gravity filters. The Agar MBBR process provides for final polishing of wastewater through the use of suspended biomass carriers, which provide a large surface area for biofilm growth enhancing the biological wastewater treatment process without increasing plant footprint.