The Development of a Calibrated Modelling Approach for Assessing Odours from Broiler Chicken Farms in New Zealand
A robust assessment of odours from broiler chicken farms is important in the current climate. The chicken industry in New Zealand has grown rapidly in recent years paralleling an increasing trend to develop lifestyle blocks and residential subdivisions within rural areas.
Odour modelling assessments are only robust and useful when the approach has been calibrated. This requires a standardisation of the method for establishing emission assumptions, modelling methodology and set-up parameters, and meteorological file development. All of these then need to be linked to an appropriate odour modelling criterion. Each step in the assessment is critical and no step can be changed without considering the effect on the criterion.
The assessment approach is based on modified odour emission relationships for broiler sheds, AUSPLUME modelling and a comparison of results to a percentile odour concentration criterion. The assessment process results have been compared to several existing broiler shed operations in Canterbury and have been scrutinised via New Zealand's Environment Court process.
The emissions profile and equations along with the model setup is described and three case studies are presented. These case studies have provided mounting evidence for the suitability of a specific odour concentration criterion. The studies involved the collation of community feedback from interviews with neighbours and historical complaints as well as surveying the levels of odour annoyance from neighbouring residents. This assessment approach is currently the only example of a calibrated odour modelling approach being developed for the broiler chicken industry in New Zealand.