By KEVIN WALKER
Michigan Correspondent

EAST LANSING, Mich. — Michigan State University has been awarded grants that total about $4 million to further its farm waste to energy projects.

The grants will fund different projects that revolve around MSU’s planned Anaerobic Digestion Research and Education (ADRE) Center, which is meant to consolidate new and existing programs in a 3,280 square-foot building south of the main campus, at the university’s farm animal and environmental research complex.

Central to these plans are research into improving anaerobic digestion plants, which researchers hope will eventually be used on a large scale across the state, either at large individual farms or at key locations accessible to many farmers.

Anaerobic digesters are systems that take biomass, such as animal manure, and convert it into usable gas, according to Steven Safferman, director of the ADRE Center and a professor of biosystems and agricultural engineering at MSU. Anaerobic digesters are good for producers because they hold manure in a tank and eliminate most of the odor that would otherwise be on a farm in the environment, potentially generating complaints from neighbors.

“The goal of the digester is twofold: one is environmental protection, the other is to provide a renewable resource on the farm,” Safferman said.

Wei Liao, assistant professor of biosystems and agricultural engineering at MSU, is leader of the anaerobic digestion project. According to Liao, agriculture contributes about 10 percent of U.S. greenhouse gas emissions, primarily as methane and nitrous oxide. About 65 percent of the methane from agriculture is attributable to livestock operations.

According to Safferman, anaerobic digesters have been used for a long time in parts of Europe, where producers have had to contend with less space and more demanding neighbors.

“Anaerobic digestion has been around for decades, but there’s been renewed interest in it because of energy issues,” he said. “It’s something that’s receiving a lot of attention. The technology has also improved. The (anaerobic digestion) reactors are more efficient and less expensive.”

Anaerobic digestion works in the following manner: manure and other biomass waste – such as food waste – are placed in a large tank, stirred and heated. If things work in an optimal manner, no additional chemicals are needed.

Although food waste has more potential energy than manure, manure is better because it has an ideal pH. Also, some types of waste aren’t well suited for anaerobic digestion because they don’t have enough nutrients.

Four beneficial ingredients are obtained from the anaerobic digestion process: carbon for energy, nitrogen in the form of liquid that can be used as a fertilizer, phosphorous as a solid and fiber that can be used in different products, such as biodegradable pots and fiberboard.

Safferman hopes that someday farmers might be able to use anaerobic digesters on their farms to heat a greenhouse year-round, which would lessen the need to import nursery stock from warmer locales. Yet, he said anaerobic digesters are far from perfect, partly because the chemical makeup of the biomass isn’t always known precisely.

“We have to be careful with digesters, because the results are variable,” he said. “There’s all kinds of things we don’t understand yet. We don’t want people putting a lot of money on the ground and have it not work out.”

The anaerobic digester that will be used at ADRE will help provide carbon dioxide to promote algae growth for an algae bioreactor, or algae culture system, at the center. This system is downriver from the anaerobic digester, according to Liao. Carbon dioxide is a byproduct of the methane that is burned.

Although a lot of the chemicals in the manure are removed in the anaerobic digestion process, the digester still produces an effluent that has chemicals in it. This effluent will also be used to promote algae growth in the algae bioreactor.

“Algae is environmentally friendly,” Liao said. “Algae is everywhere, like a natural anaerobic digestion.”

Because of the ingredients, algae can be used to make ethanol and biodiesel as well as animal feed.