Dung molecules to be converted into high value products

Carbohydrate material from animal dung, which is composed of five and six-carbon sugars, will be converted into commodity chemicals, such as glycols or diols, commonly used to manufacture antifreeze or certain plastics, and the protein components will be converted to animal feed and other higher-value products, say researchers.

The PNNL team has developed catalytic processes for converting other low-value biological materials into chemicals, such as the wastes resulting from processing corn, wheat, potatoes and dairy products. They are now turning their attention to animal manure, of which, in the United States alone, 160 million tonnes are produced every year.

“While some biomass feedstocks, such as wheat wastes, are made up mostly of clean carbohydrates, manure is messier with only about half of it consisting of carbohydrates,” said Don Stevens, Project Manager for the PNNL work. “Additionally, manure contains a much higher protein percentage and a greater mix of minerals. The production of chemicals is therefore more complex and the processes must include more extensive separations of these components to be useful for chemical production.”

However, the payoff could be huge, both environmentally and economically, says Stevens. “Animal waste is increasingly difficult to dispose of,” he said. “With fewer, but larger, animal operations across the United States, the waste is more geographically concentrated, resulting in more environmental problems. By successfully converting the wastes into chemicals, we can greatly reduce the need for open-field disposal of manure, which will reduce odour problems, methane emission to the atmosphere and run-off of contaminants into streams and lakes.”