Summary

The City of Mesa is currently working towards a Food to Energy initiative to create renewable natural gas to fuel the City's solid waste fleet. Phase One of the initiative involves developing and constructing a system to capture, refine, and use the existing biogas created from the wastewater collected at the City's Northwest Water Treatment Plant (NWWRP) to fuel the City's solid waste vehicles. Phase Two of the initiative will include development and construction of facilities to process commercial food waste and incorporate the food waste into the water reclamation process to increase renewable natural gas output. The Food to Energy initiative will advance the goals of the Mesa Climate Action Plan by diverting waste from the landfill, decreasing greenhouse gas emissions, and generating more renewable energy.

Project Status: Updated February 2023

An extensive feasibility study of the Food to Energy Initiative was completed in 2021, proving the technical, operational, and financial feasibility of the initiative. Phase one of the the initiative is at 100% design and the construction process is expected to begin in late Spring 2023. The City anticipates Phase One to be operation by mid-2024. The City is currently evaluating and pursuing opportunities to fund the Phase Two design process and cannot provide a current timeline.

Food Waste Science and Circular Economy

The two large domes near the Price 101 and Red Mountain 202 freeway interchange are part of the NWWRP where the City processes sewage and wastewater. These domes are called anaerobic digesters and are used to break down organic material in the wastewater. While the water reclaimed through this process is recycled and used to recharge underground aquifers, the biogas created from anaerobic digestion is currently "flared off", or burned, since there is no system in place to utilize it as a resource. Completion of Phase One of the initiative will facilitate collection and processing of existing biogas for use by the Solid Waste Management Department's fleet of natural gas fueled waste collection vehicles.

Phase two of the initiative will incorporate processed food waste in the form of "bioslurry" into the anaerobic digesters. Adding bioslurry to the digesters will create a unique biogas composition and will require new processes to refine it to industry standards. Once cleaned, this gas will power solid waste vehicles as they again collect food waste to generate more energy. The Food to Energy initiative aligns with the circular economy model which aims to keep resources and materials in circulation for as long as possible.

FOOD WASTE RESOURCES AND INFORMATION

EPA - Sustainable Management of Food  
USDA - Food Loss and Waste 
ReFed - Water Resources Recovery Facility (WRRF) with AD   

For more information contact waste.info@mesaaz.gov