Researchers investigate healthy commercial composting

Issue date: 20 April 2009

University of the West of England Scientists and Air Quality experts from the University of the West of England and Cranfield University are collaborating to find out more about the bioaerosols that are emitted from commercial composting facilities and their transport off-site and into the wider environment. Bio aerosols are particles that contain microbes and their associated molecules such as endotoxin.

There is an EU directive to increase the levels of recycling of commercial waste and this includes an increase in commercial composting facilities. At present there is no data on the extent or amount of endotoxin emissions from composting facilities. Such information is required to inform recommendations about how far sites should be positioned in relation to residential accommodation and how best to control emissions.

A team led by Professor Simon Jackson from the Centre for Research in Biomedicine at the University of the West of England will examine the concentrations of endotoxin in the close vicinity of composting plants. They will measure the liberation of bio aerosols during the composting process by capturing samples on filter papers.

Professor Jackson said, “Health risks associated with bio aerosols, which are airborne particles of microbial, plant or animal origin include infections and irritations of the respiratory system. We want to find out more about a specific bio aerosol component known as endotoxin that may be associated with adverse health effects including respiratory disease and lung damage if inhaled. We will be investigating the extent of endoxin release from commercial composting activity and the distance it travels.

“We will be examining the emissions of endotoxins from static compost piles and from processing activities as the compost is shredded, turned and screened. The measured emissions of endotoxins will be compared to emissions of fungi (Asperillus funigatus) and bacteria (actinomycetes). We will measure the particle size of the bio aerosols, and the concentrations of fungi, bacteria and endotoxins and then relate these concentrations to possible human impacts using an in vitro model.”

The research is in collaboration with scientists at Cranfield University, led by Dr Sean Tyrrel. The team at Cranfield will measure and identify the bacterial and fungal components in the bioaerosols. Dr Tyrrel said, “Composting operators have to meet requirements for the monitoring and control of emissions of bioaerosols set out by the environmental regulator. Although we have an understanding of the behaviour of bacteria and fungi there is little known about endotoxin releases from compost and how far it might travel in the air.”

Air Quality experts Professor Jim Longhurst and Dr Enda Hayes from UWE will carry out the air quality assessments using special suction devices to collect air samples up wind, down wind and around the site. They will use the data generated at UWE and Cranfield to produce models that will predict how endotoxin will be dispersed from composting sites under different conditions.

The research has important relevance to current policy regarding composting as a sustainable waste management option. At the moment there is insufficient high quality scientific data on the impact of bio particles on public health. This project aims to provide the data needed to help planners, waste facility operators, environmental regulators and government departments responsible for waste and planning policy develop robust policy guidelines for any future waste management facility developments.

This project is funded by the Natural Environment Research Council.

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