Anaerobic Digesters

With an anaerobic digester, you can turn livestock waste into a clean, renewable source of electricity for your farm - reducing manure management costs and lowering your utility bills.

What is an anaerobic digester?

An anaerobic digester is a container that holds manure (animal, crop or other biological products) at a given operating temperature for a period of time long enough to allow a steady-state growth of bacteria producing methane and carbon dioxide.

Biogas produced by a digester can be used as fuel for an engine to power an electric generator. Excess heat produced by the engine can be used for other farm processes, including heating water for sanitation and cooling milk.

Residuals of the digestion process are untreated wastewater mixed with effluent.

Download the Methane Energy Recovery on Iowa Farms fact sheet
By Iowa State University Extension
[PDF format – 4 pages, 142KB]

Learn how Alliant Energy uses digester technology

How does a digester work?

The manure is stored in a 124-foot-long sealed concrete tanks and heated to 98 degrees Fahrenheit.

The methane and carbon dioxide released from the heating process is fed through the connected piping to 150 horsepower, 100 kilowatt generator and a 30 kilowatt Capstone™ MicroTurbine to create the electricity.

Learn more about Capstone MicroTurbines

What are the benefits?

• The digested product has minimal odor.
• The gas produced can be used to produce electricity.
• Excess heat can be used for process heating or refrigeration applications, or building heat.
• A portion of the manure may be recycled and marketed for fertilizer.
• Improved control of flies and potential disease-carrying organisms.
• Weed seed control.
• Revenue generator.