BEAM Engineering has been hired through the MassCEC Organics-to-Energy Program and the Town of Plymouth to conduct a feasibility study on the implementation of an Anaerobic Digester in the town of Plymouth.   

 

The overall aim of the study is to find a long-term, economically viable, “green” solution to the disposal of the town's Waste Water Treatment Sludge, as well as other locally generated organic wastes.  More specifically BEAM will assess the feasibility of establishing an Anaerobic Digester and Combined Heat and Power facility to be located at the Plymouth Wastewater Treatment Plant with the purpose of renewable energy generation, the creation of organics recycling and agricultural capacity, with the ultimate goal of reducing costs.
 

The proposed site of the anaerobic digester is the Plymouth WWTP, located 131 Camelot Drive in Plymouth, MA, 02360.  The WWTP is a publicly-owned treatment works (POTW) operated by the Water and Sewer Division of the Plymouth Department of Public Works, and currently operates at a 1.75 MGD average flow, but has the capacity to treat 3 MGD.  Currently, disposal operations pump the sludge onto a truck where it is hauled off-site to Rhode Island where it is then disposed of.
 
The central organic feedstock for the proposed digester will be the sludge already generated at the WWTP facility, but will have the capacity to incorporate source-separated organics from the Town of Plymouth.  The co-digestion material of interest is pre-consumer organic waste (local generators such as supermarkets and restaurants), industrial food processing wastegreen waste (grass clippings), and post-consumer organic waste providing upwards of 4,000 tons/year of organic waste.

BEAM Engineering intends to explore how these different feedstocks and operating conditions—such as loading rates, temperature, nutrient composition, alkalinity, pH, or toxicity—could potentially upset or optimize the anaerobic digestion process to produce methane in a CHP system.

 

The waste heat generated at the CHP plant will be used to meet digester heating requirements, as well as sludge processing, operational heat, and on-site building heat.