March 16, 2007

 

US researchers trying to find new uses for cow manure
 

 

Home-buyers of tomorrow could find themselves walking across floors made from manure.

 

That is no cow pie-in-the-sky dream, according to researchers at Michigan State University and the US Department of Agriculture.

 

They say fibre from processed and sterilized cow manure could take the place of sawdust in fibreboard, which is used to make everything from furniture to flooring to store shelves.

 

And the resulting product smells just fine.

 

The researchers hope it could be part of the solution to disposing of the 1.5 trillion to 2 trillion pounds of manure produced annually in the United States.

 

Farmers traditionally use manure to fertilize their fields. But as the scale of farms has grown - with more and more animals densely concentrated in a single location - they can find themselves with too little land for the manure they produce.

 

Tim Zauche, a chemistry professor at the University of Wisconsin-Platteville said farmers are putting more money into dealing with manure, spending US$200 (euro 150) per cow per year.

 

Those costs include onsite processing and spreading, as well as transportation for offsite disposal.

 

Environmental activists and regulators are paying increased attention to the contamination of streams and underground water sources from manure runoff. And people who move into what used to be rural areas often complain about manure's odour.

 

Under pressure from regulators and the public, more large livestock operations are installing expensive manure treatment systems known as anaerobic digesters.

 

The digesters use heat to deodorize and sterilize manure, while capturing and using the methane gas it produces to generate electricity. The systems also separate phosphorus-laden liquid fertilizer from semisolid plant residue.

 

The solids have some known uses, including animal bedding and potting soil, and agricultural scientists would like to find more.

 

Scientists at Michigan State in East Lansing and at the USDA Forest Products Laboratory in Madison, Wisconsin are conducting tests on various types of fibreboard made with the "digester solids.''

 

As with the wood-based original, the manure-based product is made by combining fibres with a chemical resin, then subjecting the mixture to heat and pressure.

 

So far, fibreboard made with digester solids seems to match or beat the quality of wood-based products.

 

According to Charles Gould at Michigan State's College of Agriculture and Natural Resources, fibres interlock with each other better than wood.

 

Gould and Laurent Matuana, a forestry professor at Michigan State, recently finished a pilot study of manure-based fibreboard, funded by a US$5,000 (euro3,793) grant from the Michigan Biomass Energy Program.

 

A draft of the report concluded that fibreboard panels made with processed manure "performed very well in mechanical tests, in many cases meeting or exceeding the standard requirements for particleboard.''

 

The USDA laboratory in Wisconsin recently began an 18-month, US$30,000 (euro22,756) study to test the strength and endurance of the manure-based fiberboard and examine the economic practicality of using digested fibre to make building products.

 

One good thing about the manure-based fibre is cost, said Zauche. Farmers who currently pay to dispose of manure could soon be selling it.

 

Whether that is enough to overcome the public's squeamishness about using a manure byproduct as a building product remains to be seen, said Craig Aldir, spokesman for Washington-based The Engineered Wood Association.