Capturing and Recovering of Ammonia Using Gas Permeable Flat and Tubular Membrane Systems in a Poultry House.

Volatilization of ammonia (NH₃) gas from poultry manure is one of the major environmental and human health concerns associated with confined poultry production. Undue accumulation of NH₃ in a confined poultry house can adversely affect the health of both workers and birds. Therefore developing a technology to remove and recover NH₃ from poultry houses will lead to reduced air pollution inside and outside poultry houses, reduced ventilation costs, and a concentrated liquid ammonium salt that can be used as fertilizer. This study examined modules of NH₃ removal approaches using a gas-permeable flat membrane system and a tubular membrane system placed inside a 6.0 m X 6.0 m room in a poultry house. The systems were started by preparing 5N H₂SO₄ in an acid tank and a pH 1 solution in a concentration tank. Acids were added to the concentration tank manually to achieve a pH of 2, and then the pH pump controller and the membrane circulation modules were used to bring the pH back to 1. The membrane manifolds captured free ammonia in the air of the room. Gaseous NH₃ selectively passes through microporous, hydrophobic, gas-permeable membranes and is captured in a circulated acidic solution with accompanying production of a concentrated ammonium salt. Once NH₃ gas passed through the membrane and was in contact with the acidic solution ammonium (NH⁺₄) salt was formed, which was retained and concentrated in the acidic solution. The experiment consisted of three treatments namely; 1) Control with no birds or membrane systems, 2) birds alone, and 3) birds with both membrane systems, with separate rooms per treatments. Each room contained 400 birds with an old litter on the floor. The results of this study indicate that using gas-permeable membrane technology could be an effective method to capture and recover ammonia from poultry building facilities.