VIRIDOR WASTE MANAGEMENT LIMITED. Lostock Waste Treatment Plant. Appendix 3 Bioaerosol Risk Assessment. November 2009

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1 VIRIDOR WASTE MANAGEMENT LIMITED Lostock Waste Treatment Plant Appendix 3

2 Lostock Waste Treatment Plan Contents 1 Introduction Bioaerosols Potential Sources of Bioaerosols Pathways and Receptors Pathways Receptors Control Measures Maintenance Monitoring Conclusion...3

3 1 Introduction This considers the risk to human health of bioaerosol emissions from the Lostock Waste Treatment Plant (WTP). The aim of the is to determine that the operational, design and management measures in place are sufficient to address any risk to human health A bioaerosol risk assessment has been undertaken as the WTP is within 250m of residential properties and places of work and has been undertaken with regards to the Environment Agency Review of methods to measure bioaerosols from composting sites (April 2009). 1.2 Bioaerosols Bioaerosols are defined by the Environment Agency as microscopic, airborne particles including bacteria, fungal spores, protozoa and organic constituents of microbial and fungal origin Bioaerosols are naturally present in air. Background levels are typically between 1 and 1000 colony forming units (cfu)/m 3 in air The turning (disturbance) and shredding of organic matter has the potential to produce a range of bioaerosols. They therefore present a risk that must be mitigated Bioaerosols may cause respiratory disease or allergic reactions. The Environment Agency suggests a reference level of 1000cfu/m 3 as an acceptable limit in air (Technical Guidance on Composting Operations, October 2001) The concentration of biaerosols from the proposed operations is likely to be low. 2 Potential Sources of Bioaerosols Bioaerosols may be released during the following activities: unloading of waste at the site in the reception hall mechanical separation biodrying, including the loading and unloading of biodrying tunnels screening, refinement and outloading 1

4 3 Pathways and Receptors 3.1 Pathways Once released into the atmosphere bioaerosols will be carried by air transport. Research has shown that levels generally return to background levels beyond 250m from a composting site. 3.2 Receptors Receptors will include humans living and working close to the site, as bioaerosols may cause respiratory illness or allergic reactions in susceptible individuals. A chemical production facility lies immediately to the east of the site and there is a consented development for a bioenergy plant to the west of the site. The nearest residential properties are approximately 190m to the north, on Manchester Road The prevailing wind direction is from the southwest as shown in Figure 1 of the Air Quality Assessment (Appendix 4). This indicates that the residential properties to the north and northeast along Manchester Road are the most likely to be affected by any bioaerosols emitted from the site. 4 Control Measures Control measures will minimise the emissions of bioaerosols and hence control the risk of impact on human health. Bioaerosol control measures are briefly discussed below and set out in more detail in the Airborne Pollutant Management Plan All waste deposit, storage, handling, treatment and outloading operations will take place inside an enclosed building The building is fitted with automatic fast acting roller shutter doors which will only be opened to allow vehicles into and out of the building and will be immediately closed behind them, minimising fugitive releases of bioaerosols from the building. Other doors will be kept closed at all times when not required for access The building itself will be kept under negative pressure, so that air movement will be into the building, rather than seeping out, when the doors are opened. In addition, both the intake and output doors will be provided with air curtains, which will switch on automatically when a door is opened and provide a curtain of high velocity air that will help to reduce fugitive emissions. 2

5 4.1.5 The fan and ducting has been designed to extract air from enclosed conveyors and from above the waste receipt and waste processing areas. The waste receipt, and processing areas will have up to 2 air changes per hour. The ducting is designed to ensure that condensation on the inner surface of the stack cannot be stripped off and discharged from the stack, which will ensure that bioaerosols and dust, washed out of the air stream, are prevented from escape The air extraction system will draw air to a dust filter and biofilter. The dust filter will remove dust, including bioaerosols before the biofilter treats the air to remove odorous compounds After passing through the filters, air will be released via a 27m stack, aiding rapid dispersion and dilution of any remaining contaminants. 5 Maintenance A maintenance programme for all plant and equipment has beem designed, in accordance with manufacturers guidelines. The maintenance programme will ensure that all items are serviced regularly and that they function efficiently and effectively. Maintenance is discussed in 05 Operating Techniques. 6 Monitoring In order to demonstrate the effectiveness of the above measures, an annual bioaerosol monitoring exercise will be undertaken to measure levels upwind and downwind of the site, as detailed in the Bioaerosol, Dust, Fibres and Particulates Management Plan. 7 Conclusion All of the operations, including unloading and loading, will take place within the enclosed building. Consequently, bioaerosols will not be released into the external environment in any significant quantity. The building will be kept under negative pressure, so that air is only released via the stack, after passage through the dust filter and biofilter. This will minimise emissions and adequately disperse bioaerosols Due to the control measures that will be in place to prevent release of bioaerosols, it is considered that further quantitative risk assessment is not necessary. 3