11/24/21 
UConn Researchers Tour GLSD in Quest
to Optimize AD

University of Connecticut (UConn) researchers took a tour of the Greater Lawrence Sanitary District (GLSD) in North Andover, Massachusetts, on November 5th to see operating anaerobic digesters up close and learn more about operations and maintenance issues. The tour was organized by NEBRA, which is assisting UConn researchers working to improve anaerobic digestion operations and optimize biogas production at facilities doing co-digestion with food waste.  UConn received a grant from the Department of Energy intended to advance resource recovery from wastewater (see June 30th NEBRAMail article about these grants).

The DOE grant program seeks to harness the potential sources of energy in wastewater processes and generate enough to power an entire facility and even export energy in the form of excess electricity and even renewable fuels. That is exactly what GLSD is doing now.  Its four anaerobic digesters power two generators in a combined heat and power (CHP) system that supplies enough energy to run the treatment facility – and then some. The CHP system has the capacity for 3.2 MW of power.  On average, the CHP system generates 1,900 kW of power per day with the facility needing about 1,500 kW.  Generating power has definitely increased with the addition of a food waste slurry to the wastewater solids being digested.   

Overall, GLSD has been able to reduce its greenhouse gas emissions by an estimated 20% thanks to it AD “campus”, which is where UConn researchers went to learn more about co-digestion. The research is being led by Dr. Jeffrey McCutcheon in the Department of Chemical & Biomolecular Engineering.  The project is titled “A Digitalization, Automation, and Optimization Platform for Improved Resiliency and Consistency of Distributed Anaerobic Digestion for Wastewater Resource Recovery” and UConn has about $2 million from DOE to work on it.

The researchers hope to learn even more about what’s going on inside the digesters by inserting special millimeter-scale electrode array sensors to collect real-time operating data inside the AD units at GLSD. The project team plans to use those data in computer programs that use artificial intelligence and machine learning to improve AD operations and biogas production.

GLSD Executive Director (and NEBRA Board Member) Cheri Cousens and Brett Leavitt, Operations Manager, hosted the group and led the tour of its facility’s operations.  Joining Professor McCutcheon were several other UConn professors including Baikun Li from the Civil and Electrical Engineering Department, who is in charge of the in-situ sensor development, numerous graduate students, and one lucky undergraduate who will be working on the project.  The researchers were able to look inside and climb atop one of the digesters, which was down for maintenance at the time of the tour.

GLSD has been operating digesters for 20 years and has learned a lot about the dos and donts of operating them and associated gas cleaning and electrical generating equipment – information they are sharing with the research team, making for a productive collaboration of the theoretical and academic with practical operations.  NEBRA’s role in the project is to help facilitate that collaboration and communication.

GLSD has garnered lots of praise for its forward-thinking co-digestion, including awards from the New England Water Environment Association (NEWEA) for Biosolids Management (2019) and Energy Management (2020).  GLSD was recently recognized as a model for other wastewater treatment facilities (see GLSD serves as model for energy savings | Merrimack Valley | eagletribune.com).