Colorado Food Waste Digester Slated to Be Largest in U.S.

In anticipation of what has been called one of the largest anaerobic digestion and renewable natural gas (RNG) facilities in the U.S., food waste has been accumulated from restaurants, grocery stores and food manufacturers all over the state of Colorado to be sent to a new facility set to open in Weld County near LaSalle, Colo.

The Heartland Biogas Facility, owned and operated by EDF Renewable Energy headquartered in San Diego, Calif., has partnered with A1 Organics of Eaton, Colo., to utilize its digester processing system (DPS) to generate methane gas to create electricity.

Waste360 recently sat down with Scott Pexton, substrate sales and account management for A1 Organics, to discuss the new facility that is slated to open in the next few weeks.

Waste360: How will the waste-to-energy system at the Heartland Biogas facility in Colorado work and when will it be operational?

Scott Pexton: The Heartland Biogas (HBG) facility is an anaerobic digestion plant designed to generate methane gas from digested organic material. The plant is currently producing renewable natural gas for direct injection into an existing trans-continental high pressure gas pipeline.

Waste360: What makes the A1 Organics DPS system unique or different from others in the U.S.?

Scott Pexton: The DPS operated by A1 Organics is a unique combination of equipment and processes designed to receive a wide variety of food wastes and process them into a suitable form prior to digestion in the HBG facility. A1 Organics has reinstalled, at the DPS, our DODA bio-separation system that we have owned for seven years. The DODA is effective in cleaning plastic and other contaminants from the basic SSO stream of food waste. 

Also, A1 Organics has purchased and is installing first U.S. installation of a Tiger HS 640 de-packaging system. This enables us to process packaged food waste. This packaged material is out of date, out of specification, unexpectedly thawed or frozen, spoiled, quality control hold products, discontinued, damaged, unfit for human or animal consumption and headed for burial at the landfill. The Tiger effectively separates food from its packaging, whether it be in jugs, cartons, clam shells, bags, boxes or cans—no glass. The packaging material will be recycled or landfilled depending of the material mix and the recycling market. The processed and or prepared food waste slurry from the DPS will be fed to the HBG facility.

Finally, with all the technology in place, there will still be hiccups in the process. In anticipation of those rare events, A1 Organics composting operations are a ready backup to the digester, eliminating a bottleneck in substrate stream logistics. The generators can be assured that there is always a sustainable place for their organic waste streams to go.

Waste360: What are the benefits of the A1 Organics system?

Scott Pexton: Anaerobic digestion to energy is the highest and best use for food waste and scraps in today’s environment. We are preventing organic materials from being landfilled where it creates methane gas that vents into the atmosphere. Methane is 23 times more potent than carbon dioxide as a greenhouse gas. The system also produces approximately 450 cubic yards per day of a compost like product from the digested solids that remain after the natural gas is harvested, plus a large volume of liquid soil amendment that will be supplied to local agriculture.

Waste360: What are the challenges?

Scott Pexton: There are segments of the substrate streams that are new to this process, such as packaged SSO. This material has automatically gone to the landfill. Reversing that trend by offering a sustainable alternative is taking time to catch on in the industry. It is an easy sell to companies that have strong recycling and sustainability objectives. Other companies need to see a direct benefit in responsibly managing food waste in light of the already written off costs of their inventory shrinkage and their current municipal solid waste (MSW) expenses.

Waste360: What type of waste feeds the system?

Scott Pexton: HBG is a co-digestion facility using a mix of dairy manure and food scraps-based substrates such as fats, oils and greases (FOG), source separated organics (SSO) and food waste from packaged SSO.

Waste360: Where will that waste come from?

Scott Pexton: The FOG comes from grease traps, meat processing plants, pet protein processors, cheese manufacturing, milk processing, to name a few sources. SSO originates from grocery stores, restaurants, cafeterias, schools, etc. Packaged SSO is generated from manufacturers, warehouses, distributors, trucking companies, logistics firms, etc. Our aim is to secure and divert the material before it ends up buried in the landfill.

Waste360: How much natural gas does the system produce and what will it be used for?

Scott Pexton: In phase 1, the HBG plant is scheduled to produce 4,700 dekatherms or 4,560,000 cubic feet of natural gas per day. The renewable natural gas is sold under a long-term purchase agreement for electrical power generation.