Piggery Odour Emission Rate Validation Study

Abstract

Piggeries have the potential to cause odour impacts, and this therefore needs to be considered at all stages of piggery planning, construction and operation. The Australian pork industry invested heavily in odour research in the 1990-2000’s with a strong focus on measuring odour emission rates (OER) from effluent systems and production sheds, as well as developing separation distance guidelines. Since that time, industry practices have evolved and there are new aspects in farm design, waste treatment systems and farm management practices, which may affect odour emissions.

As well as evolutions in piggery design and operations, there have also been advances in odour impact assessment modelling, with increased capability in meteorological inputs and more detailed dispersion modelling. Advancements in odour modelling have brought with them an increased expectation of more precise odour impact prediction, but modelling piggeries is a challenging task that requires accounting for multiple, highly dynamic odour sources, complex terrain and complex meteorology. While modelling practitioners attempt to model potential odour impacts using best available modelling practices, the models are largely reliant on rudimentary OER data that may not accurately reflect current odour sources at piggeries.

Measuring OER from piggery odour sources is a complex and expensive exercise, which is the leading reason for limited OER data. There are many challenges involved in measuring odour emissions from the main sources of odour—pig sheds and effluent treatment systems. Odour from all of these sources change dynamically over time and vary spatially, making it extremely challenging to completely characterise the odour emissions from any odour source, and it makes it difficult to describe the many factors that affect odour emissions. Despite all the challenges associated with accurately measuring OER and modelling odour dispersion, they are both necessary for estimating potential odour impacts from proposed or expanding piggeries. Odour measurements only provide a snap-shot of progressively changing conditions, and there are limitations to appropriately transpose odour data measured at one farm to others in the industry due to localised and individual farm characteristics.

The objectives of this project were to review existing OER data for Australian piggeries, to measure OER from a range of piggery odour sources that are representative of current infrastructure design and management practices, and to review current odour models and modelling methods that are used for assessing odour impacts and calculating separation distances.