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Ewapower Ltd in Pietarsaari, Finland produces pellets from paper and plastic waste for burning. During 1998 and 1999, several measurements were made to determine the dust, particle, microbe and endotoxin concentrations, and also the noise level in the hall where the waste is received and pre-crushed. The noise level exceeded the Finnish recommended level of 85 dBA. The dust and the particle concentrations were low, but the microbe concentrations, especially in the summer and in the autumn, were at a level which may be harmful to health. The total concentration of microbes (both dead and alive) was high--approximately 4.8 million particles m(-3). The concentrations of endotoxins was high in summer and in autumn, from 340 to 1000 ng m(-3) and exceeded recommended values. In the winter, the concentration of the endotoxin was lower, ranging between 4.7 and 33 ng m(-3).

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.

Repeated measurements were carried out during two different campaigns between 1998 and 2001 to assess the occupational hygiene at a Finnish dry waste treatment plant. The analytical determinations were done in four different places within the processing hall of the plant: near a conveyor belt, near a jigger screen, near an after-crusher and near a bailer. Measurements were also carried out in a coffee room for employees. Concentrations of bacteria, fungi and actinomycetes were determined by two methods (six-stage impactor and Camnea method) and levels of endotoxins, dust and noise were also investigated. High concentrations of microbes and endotoxins and the noise level were found to be a real problem in the waste processing hall. Microbe concentrations were highest during management of the dry waste fraction. Endotoxin concentrations all exceeded the threshold value of 200 EU m(-3) irrespective of the measurement place, with the only exception near the after-crusher where the average concentration was always as low as 60 EU m(-3). The noise level exceeded the Finnish threshold value of 85 dBA. Problems were not easily solved through technical modifications and more radical improvements are needed. Improvements in reliability are also required in the measuring methods before their application in waste treatment plants. In particular, a new method of dust collection is recommended.