Chicken dung cleans up soil contaminated with oil

March 9th, 2009 - 3:53 pm ICT by IANS  

Washington, March 9 (IANS) Researchers in China have discovered that bacteria in chicken manure can break down crude oil into harmless chemicals, when the oil has contaminated the soil.
Bello Yakubu and associates from Wuhan University, China, point out that conventional approaches to clean-up come with additional environmental costs. Detergents, for instance, become pollutants themselves and can persist in the environment long after any remediation exercise is complete.

A more environmentally benign approach is bioremediation, which uses natural or engineered microbes that can metabolise the organic components of crude oil.

Stimulating such microbial degradation in contaminated soil often involves the use of expensive fertilisers containing nitrogen and phosphorus, and again may come with an additional environmental price tag despite the bio label. Soil hardening and a loss of soil quality often accompany this approach.

Yakubu and colleagues suggest that animal waste, and in particular chicken manure, may provide the necessary chemical and microbial initiators to trigger biodegradation of crude oil if applied to contaminated soil. One important factor is that chicken manure raises the pH of soil to the range 6.3 to 7.4 which is optimal for the growth of known oil-utilising bacteria, said a Wuhan release.

In tests, the team added chicken manure to soil contaminated with 10 percent volume to weight of crude to soil. They found that almost 75 percent of the oil was broken down in soil with the fowl additive after about two weeks, whereas additive-free soil was naturally remediated to just over 50 percent.

Contamination of soil by crude oil occurs around the world because of equipment failure, natural disasters, deliberate acts and human error.

These findings were published in the International Journal of Environment and Pollution

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