Canada - Manure Pit Scrapers Shown to Reduce Risk of H2S Exposure
Published:September 29, 2004
Source :Manitoba Pork Council
Research conducted by the Prairie Swine Centre shows the use of a manure pit scraper system in swine barns can dramatically reduce the risk of exposure to dangerous concentrations of hydrogen sulfide gas.
Hydrogen sulfide gas is produced in swine barns by the anaerobic degradation of liquid manure. Previous research suggests workers can risk exposure to dangerous concentrations while performing normal manure management tasks, such as pulling manure pit plugs.
Dr. Bernardo Predicala says scientists compared peak H2S emissions in two rooms, one in which a commercially available scraper was installed in the manure channels under the floor and one in which normal manure management practices were used.
"The peak levels in the scraper room were much much lower than the peak levels in the control room, by as much as 80 to 96 percent on the average.
We also wanted to compare these levels with actual occupational exposure limit values specified by occupational safety and health agencies which you can not exceed at any time.
In our scraper room we did not exceed that value at any time while in the control, out of our eight measurements in total, we exceeded that value three times during our measurements.
From a health and safety point of view, with respect to the health and safety of the workers, the scraper room is doing well in keeping the exposure of the workers minimized."
Dr. Predicala cautions, while peak H2S levels were reduced, peak ammonia concentrations were slightly higher in the scraper room but they did not exceed recommended limits.
He says scientists are now working on strategies that will also minimize ammonia levels.
