June 28, 2021 | AD & Biogas, Food Waste

Hennepin County Issues RFP For SSO Anaerobic Digester

Top: Food scraps being tipped at the Hennepin County Brooklyn Park Transfer Station. Photo courtesy of John Jaimez, Hennepin County

The Hennepin County, Minnesota Board of Commissioners approved $43.5 million for construction of an anaerobic digester (AD) to process source separated organics (SSO) on a 6.25-acre parcel of land adjacent to the county’s Brooklyn Park Transfer Station. The Board’s approval restarts a planning process that was well underway prior to the COVID-19 pandemic. “We had issued a Request for Qualifications (RFQ) to develop an anaerobic digester for SSO in June 2018,” explains John Jaimez, Hennepin County Organics and Recycling Specialist at the Environment & Energy Department. “There were 15 responses, which we narrowed down to a short list to receive our Request for Proposals (RFP). Plans were to release the RFP in March 2020; a critical piece of that was securing a site. The whole process got thrown off by COVID.”

The project was in limbo for about a year, but then was kick-started in Spring 2021 when the Board of Commissioners approved a Climate Action Plan (CAP). “Food waste reduction, organics recycling and anaerobic digestion are critical parts of the county’s CAP,” adds Jaimez. “The Board moved very quickly on implementing the CAP, which led to the AD project’s green light lighting up again. We dusted off the RFP and released it on June 7.”

At a minimum, the AD facility will have capacity to process 25,000 tons/year of residential and commercial SSO. However, the county is open to considering a facility with larger capacity. At this time, the county is also open to considering the acceptance of all types of food waste, including residuals from food processors, as well as potentially receiving materials from outside of the county. The RFP states a preference for a continuous high solids dry digestion system for the AD facility. “We were technology agnostic during the RFQ phase, but after evaluating the proposals and visiting facilities, we decided upon a dry AD technology,” explains Jaimez. Proposals are due in early October, with selection of a preferred vendor by early 2022. The goal is to have the AD facility in operation in the first half of 2025.

In November 2018, Hennepin County expanded a recycling ordinance to include SSO. The changes adopted require businesses that generate large quantities of food waste to implement back-of-house SSO recovery and/or recycling by January 1, 2020 and cities to offer organics recycling service to residents by January 1, 2022. The county ordinance for commercial food scraps did go into effect in January 2020, but the pandemic slowed down actual implementation. For the residential requirement, any city with 10,000 or more residents has to offer curbside collection of food scraps. Cities with fewer than 10,000 people must have at least one drop-off site for residential food scraps.

Sign up