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Monitoring bioaerosol and odour emissions from composting facilities - WR1121

Description
A significant part of government policy for waste management is focussed on diverting biodegradable waste from landfill to:
• Reduce methane emissions;
• Comply with the targets in the Landfill Directive;
• Get more value from waste through increased recycling etc.
The lowest cost alternative to landfill is open-air windrow composting (up to 2.5 m high rows of biodegradable waste in the open). The number of large composting sites in the UK has more than tripled in recent years to over 200. Currently 5 million tonnes of food and garden waste produced annually by householders is landfilled (Defra 2010), but this is targeted by government and local authorities to be diverted to composting or anaerobic digestion over the next 10 years. Composting processes release bioaerosols. Bioaerosols are composed of fungal spores, live bacteria, allergens and respiratory sensitisers (e.g., endotoxin) and can be harmful to humans and other animals.Human exposure to bioaerosols has the potential to rise over the next decade as a result of the increasing diversion of biodegradable municipal waste from landfill to open-air composting sites and the use of similar matter in agriculture as a fertiliser.

The scientific evidence on health risks from bioaerosol exposures is unclear and exposure information is incomplete. In setting policy and working with water management companies, Defra and the Environment Agency (EA)currently adopt an approach which is developed on the basis of research showing that concentrations of bioaerosols mostly decayed to background levels within 250 metres of the composting site. . A recent Institue of Medicine (IOM) review commissioned by Defra (Defra, 2009) concluded that insufficient data were available to set exposure guidelines for most components of bioaerosols and identified significant gaps in knowledge of both exposures and health effects. Specific areas of insufficient data which the report highlighted included: the lack of standard bioaerosols exposure measurement methods and metrics, variability in emissions, the scarcity of work on community exposures from waste sites, a lack of widely used biomarkers of exposure to bioaerosols and little information to support the development of appropriate stand-off distances for different types of processes.

The overall aim of this project is to provide evidence on bioaerosol production, dispersion and potential exposures from composting facilities. More specifically, this project will:
1. Undertake a comprehensive set of standard and novel bioaerosol measurements at representative composting sites to assess comparability between different methods and also to measure spatial and temporal variations.
2. Measure odours released from composting facilities and compare these with bioaerosol concentrations to see if odour is a marker of significant bioaerosol exposure.

The findings of this work will inform policy and practice in the monitoring and regulation of composting, specifically future developments of Defra’s and the EA’s position on composting and potential health effects from bioaerosols and the Environment Agency (EA) / Association for Organics Recycling (AfOR) standard protocol for the monitoring of bioaerosols on composting facilities.
Objective
Objective 1
To undertake a comprehensive set of standard and novel bioaerosol measurements at representative composting sites to assess comparability between different methods and also to measure spatial and temporal variations.
Objective 1 is further refined into the following sub-objectives:
1.1 Undertake bioaerosol measurements at representative composting sites using standard AfOR techniques to measure spatial and temporal variations
1.2 Compare measurements using standard AfOR techniques with the CEN method (an alternative filter method)
1.3 Compare measurements using standard AfOR techniques with real-time particulate detection and a PCR-based detection method for Aspergillus fumigatus
1.4 Compare measurements using standard AfOR techniques with measurements of the priority bio-markers endotoxin and glucan
1.5 Use results of study to feed into modelling community exposures as part of a future small area health study (funding provided via other sources)
Objective 2
To determine the odour emissions and then compare these with bioaerosol emissions to see if odour is a marker of significant bioaerosol exposure.
Objective 2 is further refined into the following sub-objectives:
2.1 Undertake olfactometric measurements of odour concentration at representative composting sites concurrent with bioaerosol measurements
2.2 Model the dispersion of odour and bioaerosols from site- sampled emissions to determine the extent to which odour is a marker of significant bioaerosol exposure
Project Documents
• FRP - Final Report : WR1121 Bioaerosols - FINAL REPORT   (2813k)
• ANX - Annex : Index of unpublished appendices   (170k)
• EXE - Executive Summary : WR 1121 Bioaerosols Executive Summary   (272k)
Time-Scale and Cost
From: 2011

To: 2013

Cost: £490,453
Contractor / Funded Organisations
National Physical Laboratory
Keywords
Bioaerosol              
Biowaste              
Composting              
Environment and Health