The concept of utilizing energy (heating or cooling) from wastewater processes is not new, nor necessarily complex. It involves heat exchange of raw or treated wastewater, and typically uses a heat pump to efficiently lift the fluid temperature to that required for space heating. There are a variety of proven mechanical systems for solids screening, heat exchange, and automated maintenance, that vary depending on the type of effluent and scale of the project. Efficiencies can be 300% to 700% greater than conventional fossil fuels or electric heating, with the added benefit of greatly-reduced greenhouse gas emissions.
Associated Engineering completed the detailed design and construction services for the installation of the wastewater heat recovery system that is used to offset energy consumption. Our design included an interconnection with the existing wastewater wet well. Wastewater is filtered through a specialized self-cleaning filtration unit before being passed through a heat exchanger to transfer energy to the existing low temperature building heat pump loop. The system has been in operation since 2012, with excellent reported performance.