KENOSHA, Wis. (September 28, 2015) – Kenosha Water Utility (KWU) today unveiled a first-of-its-kind biosolids handling process at its wastewater treatment plant in Kenosha, Wis. This marks a step that moves the wastewater plant toward energy independence, allowing it to more cost-effectively yield a lower-volume and eco-friendly biosolid byproduct. Key to the entire process is North America’s first installation of the Pondus Thermo-Chemical Hydrolysis Process (TCHP), an advanced technology from CNP - Technology Water and Biosolids Corporation (CNP) that gives the plant more reusable methane from waste-activated sludge than would otherwise be possible.

The Pondus Hydrolysis, which CNP has exclusive distribution rights to in North America, uses a process that leverages thermal energy and sodium hydroxide to break down the cell walls of the microorganisms in waste-activated sludge to render the sludge more digestible by anaerobic digesters. In so doing, it allows additional methane to be derived from sludge for use as biogas fuel – a step previously not possible without this technology.

“We're excited to introduce this new system to the city of Kenosha,” said KWU General Manager, Ed St. Peter. “It represents a major step forward in putting biosolids to better use for energy reuse and eco-friendly disposal,” added St. Peter. “For wastewater plants across North America, environmentally-friendly ways to hold down costs yet still provide an invaluable service to the communities is increasingly critical.”

The new process at the Kenosha Wastewater Treatment Plant is the result of the Kenosha Energy-Optimized Resource Recovery System Project – a partnership among CNP, Centrisys Centrifuge Systems, and the KWU. The project upgrades, which began in December 2014, were completed in September 2015. The new process is targeted to be up and running by November 30, 2015.

The new biosolids process will enhance the solids portion of the wastewater treatment plant operations by harnessing byproducts for reuse and further drying the finished product. And the reusable methane gas byproduct will be used as fuel in combined heat and power gas engines to supply heat and generate electrical power. The final biosolids byproduct will be solidified and reduced in volume for a final Class A Biosolid rating and used as fertilizer or fuel.

“We’re pleased to introduce this new technology to the North American market,” said CNP President, Gerhard Forstner. “It’s an ideal solution for wastewater treatment plants as they strive to implement cost-effective ways to generate biogas fuel from waste-activated sludge. Compared to similar technologies, it also offers simpler maintenance and operation with a lower initial cost, which is crucial in times when municipalities are looking to cut costs wherever they can.”

Other technologies used in the process include:

  • Centrisys THK 200 Thickening Centrifuges – This innovative technology for sludge thickening reduces the liquid volume within the sludge stream before it enters the primary anaerobic digesters. Separate centrifuges handle the thickening of waste-activated sludge and primary sludge. The thickening technology yields a composition of seven percent solids, allowing for fewer digesters and improved heat and energy cost savings.
  • Biogas Conditioning System – This system reduces maintenance and increases longevity of the CHP generators. The technology removes the moisture and siloxane that is present in the methane gas produced in digestion in preparation to fuel the combined heat and power system.
  • Combined Heat and Power (CHP) Co-generation Units – Powered entirely by the digester gas (methane), each will produce 330 kilowatts of continuous power. As such, they will power all equipment in the process as well as provide supplemental power to the rest of the plant. Additionally, the methane-produced heat will feed the dryer and Pondus system, anaerobic digesters and central plant heating loop – ultimately leading towards energy independence.
  • Centrisys CS21-4HC Dewatering Centrifuge – The dewatering centrifuge removes liquid from the digested sludge, taking the biosolids to a 28-30 percent solid concentration in order to reduce the volume of biosolids prior to being introduced into the belt dryer, saving on volume and energy costs.
  • Low Temperature Belt Dryer – The dryer takes biosolids from the dewatering centrifuge and dries it to 90 percent solid concentration, which reduces the biosolids in volume by a third. The composition qualifies the biosolid as Class A Biosolid, which allows it to be used for fertilizer or fuel applications, mitigating disposal costs for landfill.