Dr Nigel Gibson, Principal Odour Consultant, AEA Group(free)
Odour management plans offer a structured way of understanding and managing odour problems, and is the approach adopted by the Environment Agency in the new draft H4 guidance on odour.
Odour management plans can be tailored to suit the requirement of individual installations. This paper outlines the type of information that should be included in an odour management plan.
The application of the odour management planning process is demonstrated through a case study based on a Part A1 regulated site. The case study shows how (i) a simple screening risk assessment can be used to identify significant sources, (ii) odour measurement and dispersion modelling can be used to set performance targets, (iii) BAT for odour control can be established (iv) odour and pollutant measurement can be used to validate odour control plant and (v) management and reporting aspects of odour management are established.
Keywords: BAT, dispersion modelling, odour control, Odour management plan, olfactometry, pilot trials, risk assessment.
Odour regulation and odour management planning
Many agricultural, industrial and waste related activities give rise to odour emissions. Where those odour emissions are a problem, finding an effective solution can be costly, in terms of time, money and goodwill. In many instances it is not always clear exactly where the odours of most concern are emitted from, what causes those emissions and when they are emitted. Without a good understanding of the cause and scale of the emission it is difficult to identify suitable odour mitigation options – can the odour problems be resolved through improved management practice or is active abatement required? It is for this reason that a structured odour management planning (OMP) approach is now the recommended practice for dealing with odour issues.
The Environment Agency has published guidance on managing odours from Agency regulated installations [Environment Agency, 2009]. This guidance places great emphasis on the odour management planning process as a vehicle for an operator to demonstrate whether and to what extent odour needs to be mitigated. Where odour mitigation is considered necessary the OMP will need to be submitted for approval to demonstrate how the risk of odour problems will be dealt with. Once approved the OMP can be viewed as defining Best Available Technique for the process and will need to be adhered to. In extreme situations, failure to comply with the OMP could be considered to be a breach of a permit condition.
Steps to develop an odour management plan
There are various steps that should be taken when developing a comprehensive odour management plan, these being:
• A screening review of the entire process to identify and prioritise the potential sources of emission both under normal and abnormal conditions;
• An assessment of the risks of odour problems, from normal and abnormal situations, including worst case scenarios, for example of weather, temperature, or process breakdowns, as well as accident scenarios;
• The appropriate controls (both physical and management) needed to manage those risks;
• Specification of emission limits where appropriate;
• Suitable monitoring;
• Actions, contingencies and responsibilities when problems arise, including the procedures to be followed when complaints are received and
• Regular review of the effectiveness of your odour control measures.
This paper provides a practical application of the odour management process applied to a waste handling operation regulated as a Part A1 activity under Environmental Permitting. The odour management plan was required in response to an Improvement Condition that arose following odour complaints.