An Experimental Method for Evaluating Ammonia Emission Rates of Bio-Curtain

Bio-curtain (i.e., curtain) is a permeable cover equipped with a spraying system for ammonia (NH3) control in a swine facility. Previous studies investigated the NH3 reduction effects primarily based on concentration units. It is challenging to determine the actual efficiency because of the large amount of air discharged through the large surface of the curtain, and external wind rapidly dilutes and disperses the exhausted air. Therefore, this study investigates a technique to evaluate the NH3 reduction effect of the curtain in terms of emission rate. We constructed a metallic cover with a single hole around the curtain to gather the air discharged through it. The NH3 reduction effect was calculated by comparing the NH3 emission rate that was monitored in the barn exhaust fan and at the single hole of metallic cover during the non-spray and spray treatments inside the curtain at the maximum and minimum operating rate of the barn's exhaust fan. NH3 emission rates declined both non-spray and spray at the minimum operation rate of the barn exhaust fan, but the reduction effect was higher in spray conditions than non-spray. Accumulating NH3-absorbed water inside the curtain under the low ventilation of the exhaust fan caused these circumstances.