Removal of Ammonia and Airborne Culturable Bacteria by Windbreak Wall with Slightly Acidic Electrolyzed Water Spray for a Layer Breeding House

Abstract. Air contaminants emitted from animal buildings may harm the environment and public health. A windbreak wall with slightly acidic electrolyzed water (SAEW) sprayed downwind of exhaust fans offers a potential approach for the removal of some of these air contaminants, including ammonia and bacteria. This study was conducted to investigate the removal efficiency of ammonia and airborne culturable bacteria (CB) by a windbreak wall with SAEW spray for a layer breeding house. A 2.50 m height vertical windbreak wall was placed at a distance of 3 m from the exhaust fan (diameter of 1.38 m); the sides were also covered (2.10 m height). The top of the wall was covered except for an air outlet (width of 0.75 m) away from the fan. Tap water and SAEW, a novel environmentally friendly disinfectant, were used in the spraying system with 3 nozzles (flow rate of 1 L/min each) 0.4 m downwind of the fan. Separate sampling manifolds for ammonia and airborne CB were placed across the fan cone (0.3 m downwind of the fan) and diagonally across the air outlet on the top of the windbreak wall, respectively, for ammonia and CB sampling. Windbreak wall with water spray and 70 mg L^-1 SAEW spray both significantly reduced ammonia emissions from the house though the removal was small. The 70 mg L^-1 SAEW spray showed a slightly higher ammonia removal efficiency (13.2 %) than water spray (8.8 %), but no significant difference was found (p = 0.13). Windbreak wall with 70 mg L^-1 and 100 mg L^-1 SAEW spray both significantly and moderately reduced airborne CB emission from the layer breeding house (p < 0.01) but the two SAEW concentrations yield similar removal efficiencies of 39.4 to 40%. In addition to ammonia and airborne CB, the windbreak wall with SAEW spray could be a promising technique for reducing emissions from animal houses.