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.