THE OPPORTUNITY

The Western Monmouth Utilities Authority facility is rated for an average daily flow of 8.8 million gallons per day and is approximately 45 years old. This project’s focus was the anaerobic digestion facility which needs upgrades due to aging equipment, compliance with latest codes, to address safety concerns, enhance digester gas production, and improvements to the overall anaerobic digester process performance. The most recent improvements to the anaerobic digestion process system was in 2013 whereas the primary digester’s existing mixing system was removed and replaced and structural modifications to the primary digester’s floating cover structural truss system were performed to accommodate the installation of the new mixing system.

THE CHALLENGE

PS&S was to establish a scope of work to upgrade the anerobic digestion facility to meet current code requirements, address and curtail the formation of vivianite within the raw primary sludge piping and its impact on system operation and maintenance efforts, improve the anerobic digestion process system performance, and develop a comprehensive suggested construction sequence plan to minimize the impact of the project’s construction activities on the overall wastewater treatment plant’s operation during construction. Additionally, PS&S was to obtain necessary permits and NJ I-Bank Funding for the project.

THE PS&S SOLUTION

Following a structural assessment inspection of the secondary digester’s gas holder cover and conversations with the Authority centering on the overall scope of the upgrade project, a detailed and comprehensive Basis of Design memorandum was developed. The memorandum detailed PS&S’ findings from the structural assessment of the secondary digester’s cover and established numerous recommendations to address the various system components, including but not limited to the installation of new radial beam gas holder floating covers and linear motion mixing systems for both the primary and secondary digesters, application of concrete corrosion coatings systems for the primary and secondary digesters and their associated overflow boxes, digester cleaning, new sludge heat exchangers, new sludge and digester gas piping systems, new process and instrumentation control systems, new potable and service water piping systems, various concrete repairs, new enclosed waste gas flare, site work, HVAC, and architectural and electrical system upgrades. The engineering design called for significant coordination with electrical, HVAC, structural, and plumbing disciplines within PS&S to ensure all proposed equipment and associated piping systems would fit within the existing facility and operate in accordance with WMUA and safety code protocols. PS&S obtained the necessary air permit for the new flare and successfully received NJ I-Bank funding. Construction phase works have begun and mobilization to the site is expected in Summer 2025. PS&S’s role will continue throughout construction to ensure the scope of work is performed in accordance with the contract documents, applicable NJDEP and local permits.