Heat recovery system eliminates heating bills at wastewater treatment plant

Commerce Township, Mich. — A new sewage geothermal heat recovery system developed by Giffels Webster is expected to save Commerce Township $50,000 in heating costs this winter. Giffels Webster, the township’s consulting engineering firm, worked with the Oakland County Water Resources Commissioner’s office to design and engineer the system at the township’s wastewater treatment plant earlier this year.

“Sewage geothermal is a significant breakthrough in heat reclamation and can result in significant cost savings,” said Loren Crandell, P.E., LEED AP, partner, Giffels Webster. “The Commerce wastewater treatment plant is a model for the state and a new benchmark in green energy. The system is cost-effective, clean and has tremendous potential for application throughout the region.”

From January to March 2014, the heat-recovery system supplied a significant portion of the heat required at the wastewater treatment plant – all from sewage. The township estimates it will save roughly $50,000 in natural gas costs this winter as a result of this new technology. In 2012, Giffels Webster also led the township’s wastewater treatment plant expansion project, which increased its capacity from 2.4 million gallons of sanitary sewage per day to 8.5 million gallons per day.

The heat recovery system works similarly to geothermal energy by capturing heat from treated wastewater, which at the surface has a constant temperature of approximately 55 degrees. According to Crandell, the system is cost-effective, reliable, sustainable and environmentally friendly, and requires no wells.

“We are very excited about this energy-saving project,” said Jim Nash, Oakland County Water Resources Commissioner, whose office operates the wastewater treatment plant. “We are dedicated to implementing green technology wherever we can. Kudos to Giffels Webster and Commerce Township for developing a system that reduces the amount of natural gas required to heat the plant. Using the heat contained in the wastewater effluent is a fantastic idea with potential for broad application.”

Commerce Township’s wastewater treatment plant is Michigan’s first municipal facility to draw thermal heat from wastewater. Crandell says it can also be used as a local utility by pumping treated wastewater to local businesses and residents that install heat recovery systems.

Although Commerce Township only uses the thermal extraction process for heating, the system is also capable of generating energy for cooling, yielding even more savings. It also helps the township diversify its portfolio of energy sources and reduces its reliance on commercial energy providers.

In 2013, the Commerce Township wastewater treatment plant received the “Peak Performance Platinum 9 Award” from the National Association of Clean Water Agencies (NACWA) for achieving 100 percent compliance for six or more consecutive years. The award was given at NACWA’s Summer Conference & 44th Annual Meeting last month.

Giffels Webster has been Commerce Township’s consulting engineer since 1980. The company pursued the green-energy grant that made the project possible.

The firm is responsible for the design and construction of municipal infrastructure projects, including roadway construction and rehabilitation work, sidewalk and pathway construction, water main construction, sanitary sewer/storm water construction, detention basin retrofit projects and wastewater treatment plant improvements. Giffels Webster also provides construction inspection, as-built preparation and surveying services within the township.