California Department of Resources Recycling and Recovery (CalRecycle)

Compostable Materials

Anaerobic Digestion

Anaerobic digestion (AD) is the biological decomposition of organic matter with little or no oxygen. The anaerobic digestion process occurs naturally in marshes and wetlands. There are a variety of controlled systems where anaerobic technology is currently utilized in the United States, including wastewater treatment facilities (also Public-Operated Treatment Works or POTWs), and dairy manure digesters. In other countries (primarily Europe), anaerobic technology is utilized in municipal solid waste digesters to produce energy and to reduce the volume of solid waste that must be landfilled.

CalRecycle is encouraging the development of technologies that divert organic waste from landfills and comply with the Global Warming Solutions Act (Assembly Bill [AB] 32, Núñez, Chapter 488, Statutes of 2006) and AB 341 (Chesbro, Chapter 476, Statutes of 2011). AB 32 calls for the reduction of greenhouse gases and the use of low carbon fuels, and solid waste landfills are a significant source of greenhouse gases due to decomposition of organic material in landfills into methane. AB 341 takes a statewide approach to decreasing California’s reliance on landfills with an ambitious goal of 75 percent recycling, composting or source reduction of solid waste by 2020. Anaerobic digestion is being considered for many projects to divert organic materials from landfills and produce low carbon fuels.

Current Initiatives

  • Organics Regulatory Changes: As part of CalRecycle’s regulatory review process, feedback was solicited on 14 compostable material handling issues and potential approaches for addressing these issues from 2011-2014. The formal rulemaking for the revision of existing Title 14 and Title 27 regulations regarding in-vessel digestion regulations was initiated in October 2014 and the regulations will go into effect in January 2016.
  • Greenhouse Gas (GHG) Reduction Grants and Loans: The Greenhouse Gas Reduction Fund (GGRF) was established in 2012 and receives Cap-and-Trade auction proceeds appropriated by the Legislature and Governor for projects that support the goals of AB 32. CalRecycle established the GHG Reduction Grant and Loan Program to fund capital investments in anaerobic digesters and other facilities that will reduce GHG emissions by diverting organics from the landfill. A priority is to realize environmental and economic benefits in disadvantaged communities.
  • 75 Percent Initiative: Current initiatives, activities and workshops related to anaerobic digestion and organics are described within the focus areas for the statewide strategy called for by AB 341.

Program Environmental Impact Report (EIR) for Anaerobic Digestion Facilities

To assist in the siting and permitting of AD facilities in California, CalRecycle sponsored the development of a Program EIR to assess the environmental effects of anaerobic digestion facilities in California. The Program EIR also provides background on technologies, potential impacts, and mitigation measures. If you require assistance in obtaining access to these documents, call the Public Affairs Office at (916) 341-6300 or Ken Decio at (916) 341-6313.

Additional Guidance and Resources

Compostable Materials Home

Last updated: July 14, 2015
Compostable Materials,
Martin Perez: (916) 323-0834