Skip to main content


Buy Article:

$17.50 plus tax (Refund Policy)

Or sign up for a free trial


This paper assesses the potential benefits of co-digestion implementation in the state of California. The focus is to increase biogas production and renewable energy generation through anaerobic co-digestion of dairy manure and biosolids, each with the addition of food waste. In addition, the implementation of co-digestion at Inland Empire Utilities Agency's (IEUA) Regional Plant No.1 (RP-1)) and the associated issues and costs are discussed. Finally, using the experience from IEUA RP-1, cost/benefit analyses (business model) of a typical co-digestion project are discussed from the perspective of those fronting the initial capital costs (developers) and the sewage treatment plants (STPs) where the digesters are available, biogas is generated and the generation equipment is located (host facility) – assuming they are different. The goal of this business model was to provide the financial analysis for a typical co-digestion implementation in a STP that is interested to become a host for co-digestion project.

This study shows that implementation of anaerobic co-digestion of food waste with dairy manure and wastewater sludge can significantly increase the potential for renewable energy generation in California. In addition, co-digestion offers cost benefit solutions to the increasing environmental regulation requirements for better waste management of sludge, dairy manure and food waste. Given that dairy farms and food processing facilities in California are located relatively concentrated, and STPs typically have additional capacity in their digesters, it is likely that implementing co-digestion at existing STPs and/or creating centralized co-digestion plants is the trend where various wastes can be managed more effectively.

The cost/benefit analyses of co-digestion projects showed that a developer can increase shareholder value by offering the value-added service of developing new onsite generation capacity from co-digestion. Furthermore, assuming little or no generation is occurring, the host facility adds value through savings from purchasing power from the developer for less than prevailing retail rates. As long as the prevailing retail rates remain at current levels, this business of implementing co-digestion presents a good opportunity.

Document Type: Research Article


Publication date: 2005-01-01

More about this publication?
  • Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed.

    WEF Members: Sign in (right panel) with your IngentaConnect user name and password to receive complimentary access.
  • Subscribe to this Title
  • Membership Information
  • About WEF Proceedings
  • WEFTEC Conference Information
  • Ingenta Connect is not responsible for the content or availability of external websites
  • Access Key
  • Free ContentFree content
  • Partial Free ContentPartial Free content
  • New ContentNew content
  • Open Access ContentOpen access content
  • Partial Open Access ContentPartial Open access content
  • Subscribed ContentSubscribed content
  • Partial Subscribed ContentPartial Subscribed content
  • Free Trial ContentFree trial content
Cookie Policy
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more