MassDEP, through the Clean Energy Results Program, is working with Department of Energy Resources (DOER) and the MA Clean Energy Center (MassCEC) to promote the use of clean energy at wastewater treatment plants in Massachusetts.  These facilities use a tremendous amount of energy to move water, force it through filters and run waste water technologies. Anaerobic digestion is an increasingly important technology in the Commonwealth's renewable energy portfolio due to its ability to turn organic waste into a gas that can be used to produce electricity and thermal energy (heat).

Anaerobic digestion has been used at wastewater treatment plants (WWTPs) in Massachusetts for many decades as a way to reduce pathogens and sludge volumes.  Adding additional organic material (such as food waste) to biosolids at  WWTP digesters (referred to as co-digestion) has been proven to create  greater efficiencies and renewable energy for onsite use or resale to the grid.  This leads to environmental benefits from methane capture, renewable energy generation, and organic waste volume reduction.  Additionally, facilities may generate revenue from processing additional waste streams and producing beneficial fertilizer and soil amendment products.

In November 2012, MassDEP amended its site assignment, solid waste management facility, and wastewater treatment facility operation, maintenance and pretreatment regulations to build in-state capacity to process and recycle organic materials. The agency's Solid Waste Master Plan calls for the diversion of 450,000 tons per year of organic materials by 2020, which is quadruple the current capacity.  With plans to institute a ban on disposal of organic materials for large generators in 2014, the volume of materials available for co-digestion at wastewater treatment digesters will increase.  With support from MassDEP, MassCEC, and DOER, many facility operators are evaluating whether co-digestion would be appropriate and beneficial at their facilities.

The following map highlights the location of publicly owned WWTPs with Operating Anaerobic Digesters and those WWTPs Exploring the Feasibility of Recovering Energy from Organics through Anaerobic Digestion.

CERP Waste Water Treatment Plant AD legend

View Organics at WWTP in a larger map