Anaerobic Digestion

Anaerobic digestion (AD) is a process by which microorganisms break down organic matter, producing various gases and a reduced volume of semi-solid residue.  The gases produced, called "biogas" or "digester gas," include a high percentage of methane, which can be burned to produce heat and/or electricity.  Biogas from anaerobic digestion of biosolids and other organic residuals is a renewable, green fuel.  The semi-solid residue from the digestion process, called "digestate" (and/or "biosolids," if it is derived from wastewater solids and meets regulatory standards for use on land) is a stabilized material that can be used as a soil amendment, for animal bedding, or other uses, depending on the levels of further treatment.

Anaerobic digestion of organic residuals is a rapidly growing market, because it is a critical part of making communities sustainable.  In New England and eastern Canada, wastewater treatment facilities traditionally did not use AD.  Now there is booming interest in building more digesters.


Additional Resources

American Biogas Council (ABC)
AgStar Anaerobic Digestion Website
U. S. EPA Biosolids Program & Regulations
U. S. EPA - East Bay MUD Food Waste Digestion Info
Toronto Anaerobic Digestion System - "Going Green for Green" VIDEO

NEBRA Webinars & Workshops

NEBRA Anaerobic Digestion Training - Nov. 16, 2016 - Franklin, NH:  Compiled Slides

Co- Composting & -Digestion of Organics - recording of a NERC/NEBRA webinar, Dec. 3, 2015 (1 hour, 17 mins.)  Discussion of co-composting & co-digestion by Jeff McBurnie (Casella Organics) and co-digestion by Natalie Sierra (Brown and Caldwell), with input by Mac Richardson, Lewiston-Auburn Water Pollution Control Authority.

NEBRA / JETTC Anaerobic Digestion Workshop

Lewiston-Auburn WPCA, Maine • September 10, 2013

Georgine Grissop, CDM SMith:  Anaerobic Digesters 101: Process Description and Process Control
John Donovan, CDM Smith:  Basis of Design of LAWPCA Digestion / Energy Recovery Facilities
John Reilly, Hoyle Tanner & Associates:  Biogas
Dan Kelly, Tom Schwartz, Woodard and Curran:  NEWEA 2013 - Combined Heat and Power
Ned Beecher, NEBRA:  Co-Digestion: The Path to Net-Zero Energy Consumption
Travis Peaslee, LAWPCA:  Stakeholder Concerns 

Massachusetts Digester Day - May 2012

May 8, 2012.  The agenda for the day's presentations is here.
All presentations are courtesy of presenters; please contact them for permission to utilize for other than personal use.

Digester Basics - Paul Greene, American Biogas Council (ABC) / O'Brien & Gere
Biosolids Digestion - John Donovan, CDM Smith
Biosolids Regulations - Natalie Sierra, RMC Water and Environment
Digester Gas: Uses & Considerations - Michael Bullard, Hazen & Sawyer
CoDigestion of Biosolids - Natalie Sierra, RMC Water and Environment
Manure and Food Waste Digestion - Paul Greene, ABC / O'Brien & Gere
Stakeholder Concerns - Ned Beecher, NEBRA
Case Study: East Bay Municipal Utility District (EBMUD) - Natalie Sierra / Ned Beecher
Overcoming the Challenges / Discussion Slides - Wayne Davis, Harvest Power
Summary Comparison of MA DEP Biosolids Regulations v. U. S. EPA
Summary of Biosolids Recycling in MA

The egg-shaped anaerobic digester at the Nashua, NH Wastewater Treatment Facility.