Poultry farms are a significant source of air and water pollution. In the US, they are the largest source of ammonia emissions, followed by dairy and non-dairy cattle farms. Poultry farms emit over two million tons of ammonia per year. Ammonia is not directly produced or excreted by the birds but is a common by-product of poultry wastes.
Poultry manure is a rich source of phosphate and large amounts of it are used in agricultural land as an organic fertilizer. This poses an environmental risk when phosphates are washed into rivers and streams by rainwater. Phosphates lead to the proliferation of algae, harming other aquatic life and resulting in toxic conditions.
Researchers at the UK Centre for Ecology & Hydrology are investigating the use of biochar as a means of reducing air and water pollution from poultry farms in the UK. Biochar is produced by heating biomass – typically wood – to high temperatures in the absence of oxygen. The resultant material is effective at absorbing nutrients and other substances.
In laboratory experiments, adding biochar to birds’ bedding has been shown to reduce ammonia emissions from droppings by 58%. The biochar binds ammonium to its surface, preventing release into the atmosphere as ammonia gas.
Modified biochars are also proven to be highly efficient at adsorbing phosphorous. Adding a cost-effective biochar to poultry manure fertilizer could support the safe use of an important and otherwise renewable fertilizer. The biochar binds phosphates in the manure to its surface, preventing leaching and run-off into waterways.
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Biochar could help restore River Wye
Photo, posted May 15, 2023, courtesy of Ark. Agricultural Experiment Station via Flickr.
Earth Wise is a production of WAMC Northeast Public Radio
