Search

Abstract: An assessment of the fugitive release of bioaerosols from static compost piles was conducted at a green waste composting facility in South East England; this representing the initial stage of a programme of research into the influence of process parameters on bioaerosol emission flux. Wind tunnel experiments conducted on the surface of static windrows generated specific bioaerosol emission rates (SBER2s) at ground level of between 13 and 22×103cfu/m2/s for mesophilic actinomycetes and between 8 and 11×103cfu/m2/s for Aspergillus fumigatus. Air dispersion modelling of these emissions using the SCREEN3 air dispersion model in area source term mode was used to generate source depletion curves downwind of the facility for comparative purposes. [Copyright &y& Elsevier]

Highlights: [•] Bioaerosols were captured using the filter method. [•] Bioaerosols were analysed using scanning electron microscope. [•] Bioaerosols were classified on the basis of morphology. [•] Single small cells were found more frequently than aggregates and larger cells. [•] Smaller cells may disperse further than heavier aggregate structures. [Copyright &y& Elsevier]

Abstract: The emission and dispersal of bioaerosols from open-air commercial composting facilities continues to be contentious. A meta-dataset enumerating cultivable microorganism emission and downwind concentrations is not yet available. A dataset derived from repeated and replicated field studies over a period of two years at two commercial composting facilities is presented. The data characterises patterns in Aspergillus fumigatus, actinomycetes, Gram-negative bacteria and endotoxin emission and downwind concentrations. For all bioaerosols, compost agitation activities had a significant impact on concentrations; levels were variable up to 600m downwind from site. Bioaerosols declined rapidly from source and exhibited a secondary peak 100–150m from site boundary. All bioaerosols were found downwind from site in elevated concentrations. Compared to those found 100m upwind, levels were significantly higher at 180m downwind for A. fumigatus; at 300–400m for actinomycetes and Gram negative bacteria, and at 100m for endotoxins. Periodically, elevated concentrations could be found for all bioaerosols at distances further downwind. The evidence provided by this data set provides operators and regulators of facilities with reliable data to inform the location, risk assessment and bioaerosol sampling strategies of commercial composting facilities. [Copyright &y& Elsevier]

Abstract: Information on the particle size distribution of bioaerosols emitted from open air composting operations is valuable in evaluating potential health impacts and is a requirement for improved dispersion simulation modelling. The membrane filter method was used to study the particle size distribution of Aspergillus fumigatus spores in air 50 m downwind of a green waste compost screening operation at a commercial facility. The highest concentrations (approximately 8 × 104 CFU m−3) of culturable spores were found on filters with pore diameters in the range 1–2 μm which suggests that the majority of spores are emitted as single cells. The findings were compared to published data collected using an Andersen sampler. Results were significantly correlated (p < 0.01) indicating that the two methods are directly comparable across all particles sizes for Aspergillus spores. [Copyright &y& Elsevier]

Actinomycetes are the dominant bacteria isolated from bioaerosols sampled at composting facilities. Here, a novel method for the isolation of actinomycetes is reported, overcoming masking of conventional agar plates, as well as reducing analysis time and costs. Repeatable and reliable actinomycetes growth was best achieved using a soil compost media at an incubation temperature of 44°C and 7 days’ incubation. The results are of particular value to waste management operators and their advisors undertaking regulatory risk assessments that support environmental approvals for compost facilities. [Copyright &y& Elsevier]