Canada - Scraper Manure Removal System Reduces Potential H2S Emissions

Research conducted at the Prairie Swine Centre has shown hog producers can dramatically reduce their risk of hydrogen sulfide gas exposure by using a scraper system to remove manure on a daily basis. Hydrogen sulfide, or H2S, is a potentially deadly gas which is produced by the anaerobic degradation of liquid swine manure. As part of a study initiated in 2003 and completed last month, a manure scraper system was installed into one of the Prairie Swine Centre's grower finisher rooms to remove manure. Research Scientist in Engineering Dr. Bernardo Predicala says the scraper system proved very effective in controlling H2S. The objective of this study was to develop various engineering control measures to try to reduce the exposure of workers to high levels of Hydrogen sulfide. For this part of the study we compared hydrogen sulfide levels as well as other air quality parameters including ammonia concentration between a room where we installed the scraper and a normal production room which we called a control. A normal production room would be with a pit plug manure handling system. After completing four trials, the peak hydrogen sulfide concentrations were 85 to 91 percent lower in the scraper room compared to the normal production room. Further more the hydrogen sulfide levels in the scraper room were generally below the 15 PPM ceiling occupation and exposure limit value which were specified for hydrogen sulfide were as in the normal production room this ceiling value was exceeded nine times during the study." Dr. Predicala says, while the system was highly effective in reducing H2S emissions, ammonia levels actually increased slightly in the scraper room, but not to levels that would be considered a risk. However, he says, scientists will now turn their attention to developing methods to bring ammonia levels under control.