Occupational hygiene in two combined-drum-and-tunnel composting plants managing source separated biowaste and sludge

Occupational hygiene was investigated in two Finnish combined-drum-and-tunnel composting plants, Plant A (composting sewage sludge) and Plant B (composting source-separated biowaste), in 1998-2000. The concentrations of viable mesophilic and thermophilic microbes (fungi, bacteria, and actinomycetes), the total number of microbes (viable + dead), endotoxin concentrations, and noise level were determined for each plant. In addition, dust concentrations were investigated in Plant B. In Plant A, working areas were aired before the measurements were taken. Differences in microbe concentrations between the plants were statistically significant. There were more problems with microbes in Plant B, where the working areas were not aired. Also, endotoxins were a problem in Plant B; the threshold value of 200 endotoxin units per cubic meter was exceeded in several measurements.
Introduction Partly voluntarily and partly by order of the waste act, Finland is moving toward source separation of kitchen biowastes. At present, about 70 percent of Finns are sorting their [...]