Sustainability involves 3 parts: planet, profit, and people. Treating wastewater is very energy intensive, so capturing and using the methane is very sustainable. It benefits the planet because the methane gas is not released into the atmosphere. And it benefits the profit and bottom line because less energy has to be purchased to operate the facility.
The Madison-Chatham Joint Sewage Treatment Plant underwent a $3 million upgrade, in 2010, which will included improvements to the digesters. The digesters, which handle hundreds of thousands of gallons of waste at a time, were cleaned and a new mixing system designed to increase the production of methane gas was installed. Because the upgrade will make the facility more energy self-sufficient, it was designated as a "green" project.