Anaerobic Digestion Plant

City of San Luis Obispo

Hitachi Zosen Inova

Year Completed:

-Conditional Use Permit with Mitigated Negative Declaration
-APCD Authority to Construct
-CalRecycle Solid Waste Facilities Permit


The Anaerobic Digestion Plant established the first Hitachi Zosen Inova (HZI) facility in the United States. This anaerobic digestion facility processes organic matter, namely plant and food waste, collected from the regional waste service area. The digestion process produces biogas, which is placed into the PG&E power grid, as well as compost and fertilizer, utilized by the agricultural lands in the county. The plant utilized an existing 13,000± square foot building with the addition of a new 36,000± square foot building and the introduction of equipment related to the anaerobic digestion process. A new office trailer for support staff was built west of the plate cutting building.

Circumstances Unique to the Project:

  • First HZI anaerobic digestion plant (ADP) in the USA and the first ADP in San Luis Obispo County utilizing the Kompogas®
  • Cooperative partnership with Waste Connections to transport green and food waste from their customers to the ADP.
  • Supports Assembly Bill (AB) 341, AB 1826, and AB 32 and the recent Senate Bill 1383 – the State Organics. Law.