Presenter: Dr Jacqui Horswell, Centre for Integrated Biowaste Research
Presentation title: Biosolids research in New Zealand – what’s new?
Currently, landfilling of biosolids is practiced by the majority of local authorities due to perceived and real uncertainties around social and cultural acceptability and risk of alternative disposal methods. There is a strong scientific case that application to land is the most sustainable option, because biosolids are carbon-rich and contain high concentrations of valuable nutrients that can be used to bolster soil carbon reserves, thereby reducing dependence on artificial fertilisers. However, this approach is also potentially the least acceptable to the New Zealand public. The land application of biosolids hinges on the outcomes of integrating both biophysical and social science. A sustainable long-term solution must balance these considerations in the context of NZ’s soils, land use, demography and cultural setting/position. The aim of our research programme is to characterise the environmental risks arising from application of biosolids in different land management options and to integrate this knowledge with the social, cultural and economic considerations. Two case studies, (Mokai, Taupō; and Kaikōura) have investigated: 1) how combinations of contaminants from this complex matrix of municipal sewage interact with soil biota and biological indices of soil health and the utilisation of nutrients in the biosolids; 2) the regulatory barriers, economic constraints and social and cultural concerns surrounding land application, and; 3) how the benefits of biosolids application can best be realised within this risk framework. An overview of the results from the last 3 years of the research programme will be presented.
Event: WasteMINZ Conference 2013
Date: Tuesday 22 October 2013