Aspergillus fumigatus in windrow composting: effect of turning frequency

Abstract

classic, open-air windrow composting site was investigated. Independent of the turning frequency, the intially high concentrations of AF (>10 6 cfu/gDW ) were strongly reduced already after 2 weeks of composting in the center of all experimental windrows, as well as at the surface of those being turned frequently (daily). Surface AF counts, however, remained elevated (>10 4 cfu/gDW ) for the less frequently (weekly to monthly) turned windrows. Also, in this case, concentrations of AF dispersed in the air were higher. Temperature, the main factor for eliminating AF, rose faster, more homogeneously, and reached higher values in the more frequently (daily and/or weekly) turned composts than in those turned less frequently. Significant differences were seen between daily and weekly turnings of material with high a C/N ratio (40: 1), but not for the more nutrient rich composts (C/N 30:1), where temperatures were generally higher.Due to the reduction of AF on the compost surface by frequent turnings, health risks for the personnel working at composting sites can be diminished.

Bioaerosol Generation at Large-Scale Green Waste Composting Plants

“…These results were in the range 10 3 -10 6 cfu m Ϫ3 , which is in agreement with the results of other authors working with similar conditions. 6,[9][10][11][12] The amounts recorded at downwind locations D2, D3, and D5 (200 and 300 m downwind) during vigorous activity were similar to background levels, reflecting the good air dispersion (Figure 2). The airborne concentrations at these downwind locations were occasionally slightly above the background levels, but never exceeded 2.9 ϫ 10 3 cfu m Ϫ3 .…”

“…In the case of A. fumigatus, this effect may have been a result of the sanitization achieved during the composting process. 6 On the basis of the assumption that the sanitization effect would have had an impact on A. fumigatus, we would have expected a decrease in the concentration of this microorganism if the composting process was performed effectively (e.g., keeping high temperatures, frequent turning of material, and avoiding mixing with fresh materials). Piling and loading of mature compost did not involve vigorous movement of material and occurred at a relatively low frequency compared with other activities, such as shredding or screening, that required continuous movement of material.…”

Isolation and characterization of highly thermophilic xylanolyticThermus thermophilusstrains from hot composts

“…The studied site was a classic open-air windrow-composting facility previously described by Lott Fischer et al (1998). The substrate was constituted of separately collected kitchen and garden waste (50%), leaves and twigs (40%), mixed with rejects from the sieving (wood pieces from mature windrows, 10%).…”

“…In windrows, the large upper central zone may remain at temperatures higher than 70°C for several weeks (Beffa et al 1996b;Lott Fischer et al 1998). This hot zone harbors a high number of thermophilic bacteria forming a well diversified community (Beffa et al 1996a;Blanc et al 1997Blanc et al , 1999Strom 1985aStrom , 1985b, including the species Thermus thermophilus (Beffa et al 1996b).…”

Composts and Water Extracts of Lignocellulosic Composts in the Aspect of Fertilization, Humus-Forming, Sanitary, Phytosanitary and Phytotoxicity Value Assessment

“…A decrease in the frequency of Aspergillus fumigatus, considered as one of the most dangerous opportunistic human pathogens, was demonstrated during the composting process of lignocellulosic waste. According to Fischer et al [70] and Krikštaponis et al [71] and Lugauskas et al [72], spores of this fungus can be abundantly present in the air of composting chamber, waste dumps and poultry farms. The intensive development of this fungus in composts is associated with a high risk of its penetration into the air, which poses a threat to human health, in particular in the form of the so-called lung aspergillosis.…”