GreenWhey Energy is building an anaerobic digester facility in Turtle Lake, Wis., that will turn 500,000 gallons per day of dairy wastewater into enough biogas to produce 3.2 MW of energy.

The company says when it’s in full operation, the facility will be the first of its kind in the state, taking in the byproducts of the cheese production process and converting it to biogas, clean water, heat and a byproduct that may be used as a fertilizer.

Dairy plants across the US use thousands of gallons of rinse water in their cleaning cycles. Because of its diluted whey and milk, the water is full of fats and proteins, which carry innate energy. GreenWhey Energy says what to do with this wastewater has long been an issue for Wisconsin cheese makers.

At its Turtle Lake anaerobic cogeneration facility, microorganisms within the anaerobic digester will break down and digest the wastewater.

It works like this: First, water tankers and pipelines will deliver wastewater from dairies to GreenWhey Energy’s onsite storge tanks. Then the company will prepare it for anaerobic digestion, adjusting for temperature, acidity and nutrient content.

Pre-treated water will then enter the two separate anaerobic reactors, which will break down organic material and convert it to biogas, a mixture of CO2 and methane. The gas will be captured and used to power on-site generators. Excess bacteria will be used to treat future streams of wastewater.

After digestion is completed, solids will be separated from the water, dried and stored for use as a fertilizer. The remaining water will be treated and sent to Turtle Lake’s municipal water treatment facility.

Earlier this year, the Monterey Regional Waste Management District in Monterey, Calif., launched a program piloting a dry anaerobic digester from Zero Waste Energy. The dry digester uses Smartferm technology, developed in Germany, to turn organic waste such as food scraps into electricity and compost for agriculture use.