Development and Testing of an Acid Scrubber to Reduce Ammonia Emissions From Animal Rearing Facilities.

Over half of the nitrogen (N) excreted by broiler chickens is lost into the atmosphere as ammonia (NH₃) before the manure is removed from poultry houses.  This not only represents a huge waste of N (>300 million kg N/year in the US); it causes air and water pollution.  Large quantities of dust and volatile organic compounds (VOCs) are also emitted from both poultry and swine barns, contributing to air pollution and odor.  We developed and patented a scrubber for capturing ammonia and dust exhausted from animal feeding operations (AFOs). The objectives of this project were; (1) to re-design the scrubber to improve the ammonia removal efficacy, (2) conduct full-scale testing of the scrubber under controlled conditions at various ventilation rates, (3) evaluate the cost, practicality and efficacy of various acids for scrubbing ammonia, and (4) install scrubbers on exhaust fans of poultry houses located in Virginia and Arkansas and measure the efficiency of ammonia removal from the exhaust air.  The efficiency of ammonia removal by the scrubber varied from 55-95%, depending on the air flow rate, type of acid used, and the internal scrubber configuration.  This technology could potentially result in the capture of a large fraction of the N lost from AFOs, while simultaneously reducing emissions of bacteria, dust, and odors, which would improve the social, economic, and environmental sustainability of poultry and swine production.