Factors affecting toxic hydrogen sulfide concentrations on swine farms - sulfur source, release mechanism, and ventilation

摘要

In the past 25 years, we have conducted more than 20 laboratory and field studies related to hydrogen sulfide (H2S) in animal production. From millions of first-hand and real-world H2S data points, we found that sulfur (S) source, release mechanism, and ventilation are three critical factors affecting toxic H2S concentrations. Source of S determines how much H2S mass can be potentially produced. Sulfur in water for animal drinking and barn cleaning can be a more important S source than S from animal feed and can cause extremely high H2S concentrations. Release of H2S from liquid swine manure exhibits a dynamic mechanism of Bubble Release and Reservoir Effect. High H2S concentrations induced by manure disturbance and sudden H2S release depend on the amount of H2S that has been trapped in manure gas bubbles. Release patterns of H2S are complicated and irregular and are difficult to predict. Ventilation or air exchange dilutes the H2S mass in a defined space. The importance of ventilation, especially during manure operations, cannot be over-emphasized. Insufficient ventilation has claimed many deaths and injuries of farm workers and animals.