The Health and Safety Executive recently released a report on bioaerosol issues at various municipal waste handling sites, including Mechanical Biological Treatment (MBT) plants, waste transfer stations, and Energy from waste (EFW) plants. The aim of this study was to better understand the risk of exposure to dust and bioaerosols whilst handling municipal waste, the bulk of which occurs on waste transfer stations, and on waste treatment plants. To highlight achievable control standards, the study only recruited companies seen to employ “reasonably good health and safety management practices”.
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Bioaerosols are airborne particles or clumps containing biological material, such as microorganisms (like bacteria, fungi, and viruses), pollens, or cellular components (e.g. endotoxins). They are found in nature at low, harmless background levels. However, high concentrations of bioaerosols can be emitted by certain human processes – particularly those involving organic matter – and these concentrations can cause human health problems, including respiratory diseases such as asthma or bronchitis.
The HSE study found that there were three activities that could pose a risk of higher bioaerosol exposure, and therefore presented health risks to workers. There were:
- Cleaning & maintenance – this often means workers are in closer contact with untreated waste, and certain methods (e.g. dry sweeping) can generate lots of airborne dust
- Automatic sorting and processing of waste, after waste had undergone bio-drying
- Hand-sorting waste to recover dry cell batteries from the waste stream
As such, bioaerosols and dust could be controlled by further enclosing sorting machinery and conveyor systems, to reduce the exposure risk for staff. Additionally, reducing the amount of cleaning needed (e.g. by preventing spills), and using cleaning techniques with lower levels of dust disturbance, should be considered.
The report also recommended that operators of both MBT plants and waste transfer stations should measure the possible impacts of dust and bioaerosol exposure on their sites. Waste Transfer Stations are thought to present a higher risk due to there being more open waste. EFW plants, on the other hand, do not need to assess bioaerosol risks as their automated operations, and segregation of staff from dust and bioaerosols, means there is a low potential for exposure.
Currently, it is well-known that compost and anaerobic digestion plants are associated with environmental bioaerosol risks, with these sites being singled out in the M9 Technical Guidance Note on bioaerosol monitoring. As such, many of these types of sites need to conduct environmental monitoring (especially if there are any sensitive receptors near the site). Environmental monitoring aims to measure the bioaerosol concentrations emitted into the external environment by following the M9 protocol.
However, this study from the HSE refers to occupational monitoring: the monitoring of bioaerosol concentrations that a site’s employees are exposed to. It is important to distinguish the two, so that operators of waste treatment facilities know which type of bioaerosol monitoring they are likely to need to ensure that their site is safe and compliant.
The companies involved in the HSE study all regularly monitored occupational exposure to inhalable dust, but none did so with bioaerosols. This identifies an area where companies may not be doing all that they can to ensure site safety. The HSE recognised that this may be because systematically assessing bioaerosol exposure can be complex and expensive. However, periodically measuring the bioaerosol concentrations that staff are likely to be exposed to can be invaluable in helping to choose and target the best control measures for a specific site.
This HSE research has made it clear that bioaerosol exposure is a significant risk for waste employees at Waste Transfer Stations and MBT plants. As such, these types of sites ought to be conducting occupational bioaerosol monitoring every so often, if they are to guarantee that their staff are kept safe, and their health is maintained. This becomes even more true when considering the growing importance of diverting organic waste away from landfill (due to Government targets such as Scotland’s ban on all municipal biodegradable waste going to landfill by 2025).
Albion can supply consultants with the knowledge and expertise necessary for conducting a range of bioaerosol assessments, including occupational bioaerosol monitoring. Occupational surveys include reports with information on which areas and activities present the highest risks, and further advice on the optimum controls (according to the control hierarchy) that should be implemented to manage this. By analysing the risks associated with bioaerosols, and who may be affected by them, we help various sites improve the Health & Safety on their site.
Find out more about the bioaerosol work we do here:
A summary of the lets recycle article can be found on letsrecycle.com, and the original HSE report is found here hse.gov.uk
Written by Jennifer Kowalski, Environmental Scientist at The Open University, working in partnership with Albion Environmental Ltd