Compost made from cows?

By Seth Nidever

When a brutal 2006 heat wave caused cows to drop dead and start piling up at his Hanford-area dairy, Dino Giacomazzi started composting them. Composting was allowed as an emergency measure at the time because rendering facilities — the services that pick up dead cows and convert them into pet food and shoe leather, among other things — were overwhelmed with carcasses. But before Giacomazzi could finish his composting experiment, county officials yanked approval, and the process of turning deceased bovines into fertilizer became illegal again.

The concept is back, this time backed by extensive research conducted by the California Department of Food and Agriculture and the California Integrated Waste Management Board.

The method is simple.

Researchers laid down a bed of dried manure and placed four dead cows on top. The cows were covered by another thick layer of manure. Heat sensors were placed in the middle to measure temperature. Bacteria packets were placed at different places in the pile to measure whether the heat generated by the composting process kills harmful pathogens.

Then the piles were left to do what composting does: Break down organic matter into basic elements that can be used as fertilizer.

Researchers found that within six weeks, interior temperatures that soared as high as 150 degrees killed the harmful bacteria.

The odor wafting off the pile was no worse than the manure smell, said Carol Collar, the University of California dairy advisor for Kings County who participated in the research.

In four months, only some of the major bones were left.

“Now the question is, how much longer do we have to wait to get the bones gone,” Collar said.

The preliminary findings indicated that one of the project’s main objectives — to prove that composting kills the bacteria — is being accomplished, Collar said.

The finished compost could theoretically go out with the manure that is used to fertilize animal feed crops around Kings County.

The bones would likely be separated and ground up into powder, Collar said.

But land application still has some public relations hurdles to overcome, researchers say.

“I think the worst part is people’s perception of what it is,” said Tim Niswander, Kings County agricultural commissioner.

Some of the concern relates to bovine spongiform encephalopathy, more commonly known as mad cow disease.

Separate research is being done to see if composting successfully disables the proteins that cause mad cow, Collar said.

If successful, the research would likely allay concern about composted cows being uses as plant fertilizer.

But even if land application never occurs, composting would still be preferable to simply burying the carcasses or allowing them to decompose on the ground, Collar said.

The composted material could be transported to a landfill more easily than a rotting carcass, for example.

Composting would help with another heat wave kill-off like the one in 2006, but it could also be used in case of a major disease outbreak, Collar said.

Still, composting will likely be an emergency measure only.

Rendering plants like Baker Commodities in Hanford will remain the normal disposal method, since they turn the carcasses into useful commodities and are easier to regulate, Collar said.

Meanwhile, the cow-composting research project is running out of money, she said.

Researchers still want to find out if composting in the winter works as well as in the summer. And they want to study how different composting materials affect the composting rates.

UC researchers are also looking at air emissions coming from the composted material, Collar said.

Giacomazzi is hoping that the research will encourage legislators and regulators to legalize the process.

“It would be a reasonable thing to do,” he said.

The reporter can be reached at 583-2432.

(Feb. 26, 2009)

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