Recovery of Ammonia From Poultry Litter Using Gas-Permeable Membranes.

The removal and recovery of gaseous ammonia from poultry litter can benefit bird health/productivity and reduce environmental concerns of emissions from poultry production. We investigated the potential use of gas-permeable membranes as components of a new process to capture and recover ammonia from air in poultry houses. This process includes the passage of gaseous ammonia through a micro-porous hydrophobic membrane and captures it with a circulating diluted acid on the other side of the membrane. The membranes can be assembled in modules or manifolds and they can be tubular or flat. In bench-scale and pilot prototype testing, the technology captured and recovered over 95% of the ammonia lost from poultry litter.  The membrane manifolds can be placed close to the litter surface (above or below), reducing the exposure of the birds to ammonia.  Considering the ammonia is captured inside the houses, this technology could help reduce ventilation and energy needs to lower ammonia levels in poultry houses.  The results obtained in this study show that the use of gas-permeable membrane technology could be an effective approach to recover ammonia from poultry litter and other livestock operations. The final products are (1) cleaner air inside the poultry houses with benefits to bird health and reduced environmental emissions, and (2) concentrated liquid nitrogen that can be re-used in agriculture as a valued fertilizer.