Nitrogen Recovery System Reduces Ammonia Emissions in Pig Farming

This prototype reduces ammonia emissions in pig houses by recovering nitrogen for fertilizer use. In 2019 and 2020, air extraction from the room and under slatted floors achieved reductions of 0.7 to 4 kg NH3 per animal place annually, with efficiency ranging from 20% to 66%. The system produced 394 litres of ammonium sulphate solution per tonne of live weight yearly, containing 3.5% nitrogen (99% as ammonia), suitable for agricultural use. Treated air recirculation improved indoor air quality. The process incurs a cost of 9–12 euro cents per kg of live weight, but economic viability improves when fertilizer is monetised and environmental benefits are accounted for. Funded by the European Union, the project is accessible via EU-FarmBook.