Occupational hygiene in biowaste composting

Abstract

Source-separated biowastes from the Helsinki Metropolitan Area have been composted in open air windrows at Ammas suo, the Helsinki regional landfill in Espoo (Finland). The most significant problem encountered in the early stages of the process has been the formation of rancid odor causing human discomfort. The offensive odor was mainly due to car boxylic acids. A total of 110 organic compounds were detected in volatile emissions from windrow composts with an integrated sensory and instrumental method. Occasionally the temperatures in the windrows exceeded 80°C. Bacterial measurements also revealed substantial populations of bacte ria at 75°C. The concentrations of airborne microbes and endotoxins were highest during the crushing of fresh biowaste and the turning of compost, and were relatively high in sum mer and when windrows were dry. The most common fungi in the air were Aspergillus and Penicillium. Dust concentrations were consistently low. The concentrations of microbes were never so high as to constitute an acute health hazard from the occasional exposure. Continuous exposure to such concen trations nevertheless increases the risk of illness. The time, neccessary for the compost to become hygienic improved from four months to four weeks during the project. Drum composting was also tested and was found to be an alternative approach to treating organic wastes. Emissions from the drum composting were low compared to open air composting.

The assessment of airborne bacterial contamination in three composting plants revealed site-related biological hazard and seasonal variations

“…1998). In spite of the high allergic potential related to these kinds of bacteria, the dispersion of mesophilic and thermophilic actinomycetes from composting plants has been considered in relatively few papers (Tolvanen et al. 1998; Folmsbee and Strevett 1999; Taha et al.…”

“…Bioaerosol emission rate and dispersal at composting sites is influenced by a large number of factors, including materials being composted, on-site processes involved, associated vehicle movements, process equipment used, individual bioaerosol properties and geographical, topographical and meteorological conditions on-and off-site. Several studies have assessed bioaerosol exposure, originated from many activities, at and around composting facilities (Marchand et al 1995;Reinthaler et al 1997;Tolvanen et al 1998;Folmsbee and Strevett 1999;Hryhorczuk et al 2001;Lavoie and Guertin 2001;Taha et al 2005). In addition, some authors have observed significant differences of bacterial and fungal dispersion during low and high levels of composting activities (Jager et al 1994;Reinthaler et al 1997;Hryhorczuk et al 2001).…”

Emission of Volatile Organic Compounds during Composting of Poultry Litter

“…Alkylated benzenes (toluene, ethylbenzene, xylene, styrene) were detected the highest relative concentrations from the poultry litter composting process. These compounds had been also identified by Wilkins (1994), Eitzer (1995), Tolvanen et al (1998), and Komilis et al (2004) in the headspace of mixed wastes.…”

Occupational hygiene in a Finnish drum composting plant

“…The VOCs detected were typical of composting plants: carboxylic acids and their esters, some alcohols, ketones, aldehydes and terpenes (Wilkins, 1994;Hänni-nen et al, 2002;Tolvanen et al, 1998;Wilber and Murray, 1990). The overall odour was sour, sweet, a bit rancid and biowaste-like at both sampling sites.…”