MEDINA COUNTY, Ohio — A wastewater treatment plant in Medina County is using an innovative system to reduce costs and become more environmentally friendly.
At the county's Water Reclamation Facility, part of the treatment process is being powered in part by biogas which comes from waste byproducts.
Sludge, a biological byproduct that is part of wastewater treatment, would typically “be hauled to farm fields or land-filled or incinerated,” said Philip Cummings, superintendent of the plant.
Cummings has spent the last 44 years treating wastewater. For most of that time, he said, the county had used a specific process to treat wastewater.
“We had a heat treatment process that pasteurized the sludge and allowed us to thicken it so we could transport it to farm fields and meet the EPA requirements for its disposal,” Cummings said.
Several years ago, after years of a pilot project, the county decided to try something new. Upgrading the heat treatment process would have cost $17 million, according to county administrator Scott Miller.
Instead, the county spent between $30 million and $35 million for anaerobic digesters and a Cambi system, which allows bacteria to turn sludge into biogas.
“We would be able to produce our own electric here at the plant, and we could also be more environmentally friendly,” Miller said.
The process began running 24 hours a day, seven days a week, in mid-December. Miller said the estimated savings of this process over the old process are expected to be $1.4 million per year, which he said would go toward paying the debt issued to finance this project, a 30-year bond.
“So in reality, it’s not costing us anything because the savings is being used to cover the cost of the bond,” Miller said.
Sludge goes into 800,000-gallon tanks at the plant and stays there for 15 to 20 days in temperatures of 100 degrees Fahrenheit. One tank holds sludge in storage, while bacteria in the other convert the sludge into a 60 percent methane product.
That product, Cummings said, can then be burned in an engine, helping power the treatment process.
“This is actually a net gain in energy that we’re using to reduce the amount of power that we’re going to use to run the process, run the plant itself,” Cummings said.
Anaerobic digesters are not new, but the Cambi system is. It’s currently used at one other plant in the United States, which is in Washington, D.C., according to Cummings and Miller.
What’s being done in Medina County, though, is new, with a combination of anaerobic digesters, the Cambi system and another process to make a crystal used in fertilizer.
“We want to be on that cutting edge,” Miller said. “We want to be out in front and we want to be the leaders.”
Plant leaders noted that there are 35 Cambi systems in operation in Europe, with 17 of those in the United Kingdom.