By Jake Brown
At first glance, the work at the Kinross Wastewater Treatment Plant (WWTP) might appear like an episode of “Dirty Jobs.” Once you get past what WWTP’s Superintendent Greg Wright calls the “eww factor,” there is a highly technical and scientific process that serves as a vision into the future of how wastewater and food waste are managed. With the help of a scientific process called “anerobic digestion” and two generators, waste is now becoming powerful.
Turning food waste and wastewater solids into energy is quite a process. First, Kinross WWTP receives its food waste from local partners. Their partners separate their food waste from other waste and place it into specially marked containers. The food waste is placed into a large processor which separates the food waste from the plastic and cardboard containers. Once the food waste is separated and ground into a slurry, it is carefully mixed with human bio-solids and co-digestion begins. Microbes, or “bugs,” digest the slurry producing a biogas which is cleaned and converted into usable heat and electricity using generators.
Getting the most efficient mix of food waste and biosolids is something that Wright and his team are continually working on.
“We are in the experimental stages,” said Wright when discussing the mixing process.
Keeping the environment of the co-digestor in a steady state is very important to successful generation of energy as well as successful wastewater treatment. The chemical components and acidity of the co-digestor must be constantly managed and monitored. Wright describes the process like the human stomach. Provide smart and healthy inputs and your stomach digests without a problem but add in garbage food and your stomach might get upset. Since the Kinross WWTP is the only one of its kind in the Eastern Upper Peninsula, they must experiment to pave the way for other treatment plants across the UP.
In 2018, the Kinross WWTP finished upgrades that included adding two generators which convert biogas created in the wastewater treatment plant to energy. In early 2021, phase three was completed giving the facility the ability to process food waste in the same fashion through the co-digestion process. Thanks to this combination, the facility can now produce its own energy and heat for their buildings by processing waste.
The Kinross WWTP participates in Cloverland’s net metering program. Any excess generation produced by WWTP is credited back to their plant on their next electric bill. Currently, the plant is still reliant on additional electricity to operate, but in the future, WWTP could operate solely from electricity produced from the digestion process.
Generating electricity from waste comes with a few challenges, and one of the challenges for Wright and his team is ensuring there is enough supply of food waste to operate the process. Thanks to local restaurants, schools and co-ops, the plant has regularly scheduled pick-ups of food waste. Lake Superior State University stepped up as a large partner for the plant by separating their food waste for pickup by plant employees, providing a consistent stream of food waste. Partners have all been essential in providing food waste, and Wright’s hope is to increase their partnerships to process even more food waste at the facility.
The main goal for Wright and his team? Create as much energy as the plant consumes.
“It’s a big goal for the community. We have a road to get there and I’m hopeful the community will reap the benefits.”
Kinross WWTP is well on its way and with more experimentation and more partners delivering their food waste, resulting in increasing energy generation while decreasing food waste going to landfills.