Saxnäs wastewater treatment plant has a heated area of 80 m², which was previously heated with direct-acting electricity. Consumption was previously 36.7 MWh for a normal year. Evertherm's ARV system solution was able to replace most of the energy supplied with renewable energy directly from the wastewater.
After commissioning, the annual electricity consumption for heating is 7,7 MWh, which corresponds to a 79 % reduction in electricity use.
"After two years in operation, electricity consumption for heating has decreased to a quarter, based on recycled energy from wastewater. After all, we have replaced direct-acting electricity with heat recovery, so environmentally and energy-wise it is a direct benefit. It has also been done completely without any operational disruptions which is impressive!"
The property has converted from direct-acting electricity, to instead source the energy via Evertherm ARV, whose collectors are located directly in the waste water treatment plant's final basin. This is done using a 14 kW heat pump that delivers heat to a waterborne aerotemper in the process hall and a fan convector in the office. The installation was commissioned in May 2014 and has since been running without interruption or maintenance, no cleaning of the collector has had to be done and the logging shows that the collector delivers the same power throughout the year.
Based on the positive experience in Saxnäs, the municipality chose to go ahead and convert its other two wastewater treatment plants, Klimpfjäll spring 2016 and Kittelfjäll in autumn 2017.