Centrisys/CNP PONDUS Thermal Hydrolysis Process Helps City Of Salem Reduce Biosolids Disposal Costs And Increase Digester Capacity

Operational PONDUS and Centrisys centrifuge system enables Salem Wastewater Treatment Plant in Salem, Ohio to improve dewatering performance, increase biogas production and maximize existing treatment infrastructure.

Kenosha, WI – Centrisys/CNP, a leading North American manufacturer of decanter centrifuges and advanced biosolids treatment technologies, announced the successful startup and operation of its PONDUS^® Thermal Hydrolysis Process (THP) and Centrisys CS18-4 decanter centrifuge at the City of Salem Wastewater Treatment Plant in Salem, Ohio. The integrated system is helping the utility improve dewatering performance, reduce biosolids disposal costs, increase renewable biogas production and maximize the capacity of its existing anaerobic digesters, all while providing a simple, cost-effective solution for a growing community.

Serving approximately 12,000 residents, the Salem Wastewater Treatment Plant implemented the PONDUS system as part of its Phase 3 facility improvements to modernize biosolids processing and reduce reliance on outsourced dewatering services. Prior to the upgrade, the utility contracted outside services to periodically dewater stored sludge, adding significant operational costs.

"Salem was looking for a solution that would improve dewatering, increase digester performance and allow the plant to become more self-sufficient," said Gerhard Forstner, president of CNP. "By combining our PONDUS Thermal Hydrolysis Process with a Centrisys decanter centrifuge, the plant is now producing more than 30 percent dry cake solids, reducing biosolids volume by approximately 25 percent and lowering transportation and disposal costs while generating additional biogas for on-site use."

The PONDUS process thermally and chemically conditions sludge prior to anaerobic digestion, making solids more digestible while improving dewatering performance. Unlike conventional thermal hydrolysis systems, PONDUS operates at atmospheric pressure and requires no pressure vessel, making it simpler to install, operate and maintain. The compact system also enabled the City of Salem to install the equipment within its existing facility, avoiding the need to construct a new building.

Following startup, Centrisys/CNP worked closely with the City of Salem to optimize system performance as plant operating conditions evolved. The collaborative effort included refining instrumentation and process controls to accommodate lower-than-anticipated operating flows, ensuring reliable long-term operation.

Forstner added, "The successful startup reflects the partnership between the City of Salem, Burgess and Niples as the consulting engineer, Stanley Construction serving as General Contractor, our manufacturer representative FCM Equipment, and the Centrisys/CNP team. Our commitment doesn't end when equipment is installed. We worked alongside the customer throughout commissioning to optimize the system, and today the plant is realizing the performance improvements it set out to achieve."

In addition to reducing disposal costs, the new system enables Salem to increase solids loading to its existing digesters, effectively expanding treatment capacity without constructing additional digester infrastructure. This allows the utility to accommodate future growth while making better use of existing assets.

"PONDUS fills an important niche for small and mid-sized wastewater treatment facilities," said Forstner. "Utilities can achieve the proven benefits of thermal hydrolysis, including increased biogas production, improved dewatering and greater digester capacity—all through a simple, compact system that is practical and affordable to own and operate. All those benefits can be achieved with PONDUS THP without hiring additional personnel at Salem.”

For more information about the PONDUS Thermal Hydrolysis Process and Centrisys/CNP biosolids treatment technologies, visit www.centrisys-cnp.com.