The system can run on a continuous basis without operator attention or in low flow scenarios, the system may run on shifts. By using methane from anaerobic digestion as the energy source for heating the sludge, energy consumption is very low. In most cases the heated pasteurized sludge will provide the digester heating requirements.
A progressive cavity pump moves the sludge through the Heat Recovery Exchanger where it is heated to approximately 90 deg. F. The Heat Recovery Exchanger runs counter current to the final product, allowing both heat recovery from the final stream and the reduction of heat of the final product which enters the mesophilic anaerobic digester. The Primary Heat Exchanger then heats the flow to just above the mandatory temperature of 158 deg. F. The sludge runs countercurrent to hot water from low pressure hot water boilers.
A second pump moves the sludge through the Plug Flow Reactor to provide the required 30-minute detention time at temperature. The ECO-THERM™ produces Class “A” sludge that is completely in accordance with U.S. EPA 503 regulations. The patented continuous process plug flow reactor positively ensures the sludge is exposed to the critical time and temperature conditions. A third pump moves the sludge through a Cooling Heat Exchanger, which maintains the proper temperature of the anaerobic digester. The anaerobic digester reduces volatile solids and provides for vector attraction reduction, resulting in Class A biosolids.