Composting organic waste is an important component of the waste management process in the UK and the strategy to reduce waste to landfill, and as a result there has been an increase in the number of commercial composting operations. Microbiological activity is fundamental to the composting process, therefore any handling of composting material is likely to make airborne significant quantities of those micro-organisms (referred to as bioaerosols). Workers mechanically handling compost on these sites may therefore be at risk of considerable exposure to bioaerosols depending on their work task, their proximity to the bioaerosol source and the control measures put in place. In addition, because the work is largely done out of doors, there is the potential for bioaerosols generated to disperse some distance from the point source. Consequently, there is concern that people living or working in the vicinity of waste composting sites (sensitive receptors) may also be exposed to these bioaerosols.
Bioaerosols were sampled at sites representative of commercial scale waste composting in the UK. The samples taken were linked to specific activities likely to generate compost bioaerosols, such as turning and screening, and samples were collected from as close as possible to the source of emission. The dispersion of bioaerosols from compost handling activities was estimated by collecting bioaerosol samples at several points downwind increasing in distance from the emission site up to 250m. Upwind background samples were used as a benchmark. The sampling took place during both winter and summer periods to provide an insight into the differences in bioaerosol generation that may exist.
This report and the work it describes were funded by the Health and Safety Executive (HSE). Its contents, including any opinions and/or conclusions expressed, are those of the authors alone and do not necessarily reflect HSE policy.
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