Shifting the Paradigm: Anaerobic Digestion and CHP for Small WWTFs

Many wastewater treatment facilities (WWTFs) in New England reside in one of the costliest electrical energy regions in the country and face a multitude of challenges including high energy costs and limited options for the beneficial reuse and disposal of biosolids. When designed and implemented correctly, an anaerobic digestion process integrated with a combined heat and power (CHP) system can be one of the most effective methods to help large and medium-sized WWTFs overcome these challenges. However, traditional methods of anaerobic digestion are typically not cost-effective for WWTFs with capacities less than approximately 10 MGD. The findings from a feasibility study performed by Brown and Caldwell show that anaerobic digestion with CHP can be developed cost-effectively using co-digestion and lower cost tank construction materials to provide the benefits of renewable energy production and sludge volume reduction for small to medium sized WWTFs. In addition to reductions in annual operating costs, anaerobic digestion and CHP projects can qualify for many new state and federal funding opportunities and incentives for renewable energy production and greenhouse gas reduction. Although recently developed, these programs have been continuously funded and continue to grow. Currently, Brown and Caldwell is applying for new federal funding opportunities as part of the American Reinvestment and Recovery Act, 2009. These include the US Department of Energy grant program for CHP systems under the Clean Energy and Industrial Efficiency Program, the Energy Efficiency Construction Block Grant Program, and the MA DEP Clean Energy State Revolving Fund. Source: WEFTEC 2009 Proceedings