Organic wastes make up a large portion of New Zealand's solid waste stream (approximately 40% based on 1997 data). This volume substantially reduces the life of landfill facilities.
In the process of breaking down, these wastes contribute to the generation of leachate and methane. Uncontrolled leachate discharges may contaminate surface water bodies and groundwater aquifers while methane released to the atmosphere contributes to global warming.
Bioenergy enables the clean disposal of biomass in a manner consistent with the waste management strategy. More...
Many cities and districts throughout New Zealand have established composting facilities for organic garden waste. While individual councils have information on diversion of organic waste from landfill disposal, this data has not been aggregated and
consequently there is limited information available at a national level on the total volume of organic waste generated and the amounts diverted from the landfill.
The relationship to climate change policy is significant. The New Zealand Government’s Preferred Policy Package on Climate Change includes a reliance on the New Zealand Waste Strategy to reduce methane emissions from landfills by approximately 35% by 2010.
Progress made under the Strategy will be reviewed by the Climate Change Project in 2005 with the potential for more direct intervention at this stage should the achievements of the Strategy be limited.
Some larger landfills in New Zealand are capturing a percentage of the methane produced through waste decomposition and burning it to generate ‘renewable’ energy. However capture of methane from landfill waste decomposition is an inefficient way to recover the potential energy within organics. Typical capture rates are in the order of 30% to 50% of the methane produced.
1. By December 2003, all territorial local authorities will have instituted a measurement programme to identify existing organic waste quantities, and set local targets for diversion from disposal.
2. By December 2005, 60 percent of garden wastes will be diverted from landfill and beneficially used, and by December 2010, the diversion of garden wastes from landfill to beneficial use will have exceeded 95 percent.
3. By December 2007, a clear quantitative understanding of other organic waste streams (such as kitchen wastes) will have been achieved through the measurement programme established by December 2003.
4. By December 2007, more than 95 percent of sewage sludge currently disposed of to landfill will be composted, beneficially used or appropriately treated to minimise the production of methane and leachate.
5. By December 2010, the diversion of commercial organic wastes from landfill to beneficial use will have exceeded 95 percent.
Government's Waste Management Strategy.