Prior to the 2010 Olympics in Vancouver, we wrote about how the village was planning to extract waste heat from the sewer system to provide a sustainable solution to heating the housing for athletes. Last year, a company in Brainerd, MN set out to accomplish a similar goal. Now we bring you a Five Friday Facts looking at just how much energy is in our sewers. The following facts come from a National Geographic story last month.
- Americans flush 350 billion kilowatt-hours of energy into the sewers each year—roughly enough to power 30 million U.S. homes
- The first big wastewater heat recovery system in North America is in Vancouver, British Columbia, providing 70 percent of the energy needs to the community known as the Olympic Village. A system installed at a group of townhouses in the city reduced their energy usage by 75 percent, aiding the development in achieving LEED Platinum.
- In Chicago a sewage heat recovery system went online in May. The $175,000 system, designed by a University of Chicago professor, was funded 50-50 by the district and the private nonprofit Illinois Clean Energy Community Foundation. As a result, energy costs for heating and cooling were reduced by 50 percent at the facility. The Chicago system captures its energy from effluent, or treated wastewater, rather than raw sewage.
- Even in midwinter in Chicago, the water leaving the treatment plant is a relatively constant 55°F (13°C), even if the air outside is significantly below freezing.
- Expected ROI for the system is three years.Currently, heating and cooling the buildings uses only 2 percent of the potential energy in the effluent, leaving room for future expansion.
