PAUSE for thought the next time you take a swig from a plastic bottle. In
future, that bottle may be made from manure.
Making products such as plastics and antifreeze from animal waste would have
big environmental and economic benefits, say researchers at the Pacific
Northwest National Laboratory (PNNL) in Richland, Washington.
Because farm animals, especially cows, don鈥檛 digest their food completely,
their manure is rich in carbohydrates and proteins, they say. The carbohydrates
could be separated out and converted into chemicals such as glycols and diols,
which are used to manufacture antifreeze and certain plastics. Proteins could
also be separated from the manure and converted into animal feed and other
higher-value products.
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The PNNL team has made a start by measuring the amounts of carbohydrates that
can be isolated from manure. 鈥淸But] the research is at an early stage and we
don鈥檛 have hard numbers,鈥� says Don Stevens, the project manager at PNNL.
鈥淭his is potentially a great untapped source,鈥� says Bernard Witholt, who
specialises in the bioconversion of organic compounds at the Institute of
Biotechnology at the Swiss Federal Institute of Technology in Zurich. 鈥淚t鈥檚
certainly worthwhile looking at this as it costs money to get rid of waste. The
crucial factor is whether this is economically viable. Many have tried and
failed to develop an efficient process.鈥�
The PNNL team has already successfully extracted and converted carbohydrates
from other biomaterials, such as the by-products from processing corn, wheat,
potatoes and dairy products. But Stevens admits that manure is more of a
challenge. 鈥淲hile 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,鈥� he says.
So they have teamed up with researchers at Washington State University who
are experienced in separation chemistry. If this partnership is successful, the
pay-off could be huge, both environmentally and economically. 鈥淎nimal waste is
becoming increasingly difficult to dispose of,鈥� says Stevens. 鈥淏y 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
濒补办别蝉.鈥�
Using manure could also help reduce industry鈥檚 dependence on oil. Most
chemicals used as raw materials for manufacturing are derived from petroleum.