Presenter:  David Lindsay, Eunomia, Josh Fyfe, MfE

Presentation title:  

The anaerobic decomposition process of organic waste in landfill can take many years. In order to calculate the amount of methane released, it is necessary to look back to estimate the quantity of waste disposed of since 1950. Waste levy reporting is hoped to improve the accuracy of future Inventory reports.  This paper presents the methodology and key findings of work undertaken for the Ministry for the Environment in generating historical landfill estimates for use in the NZ GHG Inventory.  A review of available information regarding waste management in New Zealand was carried out and gave an insight to the developments over the last 100 years. While the research was focused on identifying historical data that could inform estimates, the historical review also provided useful context in explaining shifts in waste management practices over time.  A method for estimating the amount of waste disposed of at landfills since 1950 was developed, drawing on the historical research, and accounting for the IPCC methodological requirements.  As well as the growth in waste production other important factors for determining the methane generation are waste composition and disposal site management practices. These parameters in the IPCC model have also been refined as a result of the project.  A difference of 18% was found between the NZ GHG Inventory predictions of the quantity of waste to landfill and the waste levy data reported since 2009. Possible explanations for the change include:   Quantities used in the IPCC inventory have included estimation of tonnages.   Increased waste minimisation and recycling  Ø A decline in the amount of waste landfilled due to economic conditions.    The avoidance of levy payment through under-reporting of waste tonnages.   Diversion of material to non-levied sites.  This paper makes comment on these changes and how they may influence future reporting.

Event: WasteMINZ Conference 2013

Date: Thursday 24 October 2013