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Anaerobic Digesters: An Overview Image

Anaerobic Digesters: An Overview

Simplot scientists and engineers are using anaerobic digesters to convert waste into gas that can be used to save money and reduce energy footprint.

For Simplot, it all goes back to the farm. Our values are rooted in the ways that agriculture operations maximize efficiency and minimize waste. If there is a byproduct left over, a smart farmer figures out how to use it.

What is it?
Anaerobic digestion uses bacteria to consume waste product and create methane, a core component of natural gas and other fuels. The waste and bacteria are mixed and then stored in an airtight container. The bacteria use the waste as a food source and in the process create a gas byproduct called methane.

What is the science?
The process is similar to the one that created natural gas deposits underground. As bacteria consume organic material they create gas. The process happens in a variety of natural settings, but we create our own setting to use this process at our plants.

What kind of waste?
It can be animal waste from a feedlot or plant material leftover from the manufacturing process.

How does it work?
Over a series of stages, the waste is combined with water and bacteria in a temperature-controlled, air-tight tank. The bacteria break down the waste into components that can be re-used, and in the process create, methane that can be used as fuel.

What is left over?
If the methane gas is trapped and stored properly, it can be used as an energy source right there at the plant. In addition, the process leaves behind a thick sludge, rich in nutrients and perfect for use as a plant nutrients. 

What are the variables?
Although some of the fundamentals are similar, this is not like a home compost system where we can let the process take care of itself. To gain maximum benefit, our teams closely monitor the anaerobic digestion process and adjust variables, such as temperature and alkalinity, along the way.

Why do we do this?
The methane is actually one of several great benefits from the process. Anaerobic digestion also reduces waste and odor.

How does it help Simplot?
While the process saves us money and reduces waste, it is also reflective of our values as a company with deep agricultural roots. As any good family farm operation knows, sustainability is not a buzz word. It is a way of life devoted to reducing waste and reusing materials.

Information provided by the U.S. Department of Energy sustainability program for farms and ranches.