Many wastewater treatment facilities face the challenges of high energy costs and limited options for biosolids use and disposal. While anaerobic digestion integrated with a combined heat and power (CHP) system can be one of the most effective methods to overcome these challenges, such methods have traditionally not been cost-effective for smaller facilities — smaller than 10 mgd (38,000 m3/d). But a recent study has shown that anaerobic digestion with CHP using industrial and farm-type digester tanks and codigestion of municipal solids with highly degradable organic feedstocks can be technically feasible and economically beneficial for small to medium-size wastewater treatment facilities (WWTFs) with no digestion infrastructure. The study findings ultimately led to the design and construction of a new anaerobic digestion and CHP facility for the Town of Fairhaven (Mass.) WWTF, a 5.0-mgd (19,000-m3/d) facility with an average daily flow of 2.7 mgd (10,200 m3/d). The WWTF used new federal funding for municipally owned renewable energy systems through the 2009 American Reinvestment and Recovery Act (ARRA) to add these processes.
Shifting the Paradigm: Anaerobic Digestion and Combined Heat and Power for Small Treatment Plants
Authors: Eian Lynch and William Fitzgerald
2010 Water Environment & Technology magazine, Vol. 22, No. 8, pp. 64-69