Anaergia to help build food waste and wastewater sludge co-digestion facility

June 6, 2023
By expanding the Marina, California treatment facility’s capacity, Monterey One Water will receive and co-digest food waste in addition to its existing wastewater biosolids processing.

Anaergia, an anaerobic digestion solutions company, announced that it will provide technologies to help Monterey One Water make renewable energy from both wastewater and food waste.

The project will expand anaerobic digestion capacity at the wastewater utility’s regional treatment plant in Marina, California, and provide organic waste receiving and pre-processing equipment.

The equipment and expansion will allow the utility to receive and co-digest food waste from its existing digesters, which are currently used to process wastewater biosolids.

The digestion will produce renewable gas to generate electricity and heat at the Monterey One plant.

Along with the ability to co-digest food waste with biosolids, Monterey One will benefit from a significant expansion of digester capacity to provide operational flexibility.

The project will return a mothballed anaerobic digester to service and provide Anaergia’s digestion tank mixing technology to process food waste with biosolids without impacting operations. The new technology will simultaneously improve performance and save energy.

“By upgrading its infrastructure to enable co-digestion of food waste along with its wastewater, Monterey One Water will now not only recycle water, it will also recycle organic waste that would have otherwise created methane emissions in landfills,” said Andrew Benedek, chairman and CEO of Anaergia. “This turns a big problem into a huge benefit and ultimately is what will make a net-zero future possible for planet earth.”

The project will increase biogas production from the plant’s four digesters by more than 150%, which will be used to make up to 1.6 MW of renewable electricity via on-site combined heat and power (CHP) engines. The increased energy production will provide more than 100% of the plant’s power needs, reducing operating costs, supporting revenue generation, and increasing resiliency and reliability.

This expansion in onsite energy generation is an asset to the development of a joint microgrid that will be shared by Monterey One neighbor and regional solid waste agency, ReGen.

The upgraded anaerobic digestion technologies and new waste receiving equipment will assist the region’s solid waste industry, by enabling diversion of food waste from regional landfills to advance compliance with California’s SB1383 legislation.

CalRecycle, California’ Department of Resources Recycling and Recovery, will provide $4,218,900 in grant funds, minimizing impact on the utility’s ratepayers by offsetting most of the project’s cost. Work on the project is expected to begin in Q2 2023 and be completed by Q3 2024.

“With support from CalRecycle, we have a unique opportunity to co-digest wastewater solids with food waste to produce more green energy, which will both reduce our operating costs and cut our carbon emissions,” said Paul Sciuto, general manager of Monterey One Water.