The aim of the National Landfill Census is to review the progress that has been made against previous National Landfill Census results in 1995 and 1998/99, and the Landfill Review and Audit in 2001/02. The information was gathered using a survey, which was sent out to landfill site operators and some regional authorities. The questionnaire has remained relatively unchanged from previous years to ensure continuity of time-series data. The focus of the questionnaire was on the siting, design, monitoring and operation of landfills.
The results show that New Zealand landfills continue to improve and move towards generally accepted best practice. The survey found that the total number of operating landfills continued to decrease, down 48 per cent from 2002. All landfills now have the appropriate resource consents to operate. Landfill design has shown significant progress: over half of all landfills have an engineered liner in place to prevent leachate, and over three-quarters of landfills collect leachate. Over 80 per cent of landfills require documentation when hazardous waste is disposed of, and over 90 per cent measure and charge for the disposal of waste.
The survey also identified areas that need to improve. Although the proportion of landfills collecting landfill gas has doubled since 2002, this still only occurs in one-fifth. The percentage of landfills sited on low-permeability underlying material has stayed the same since 1998/99.
Additional progress in some areas is hindered by various factors, the most problematic being the length of consent periods granted under the Resource Management Act 1991 (RMA) (up to 35 years). In some cases, landfills that received consent to operate soon after the introduction of the RMA could still have consent to operate until after 2020 even though they do not meet present best practice. Upgrading these landfills to comply with best practice before the consent period is up can be considered impractical because the cost is high.
With landfill numbers decreasing and improvements in landfill design and operation, the 2006/07 National Landfill Census shows that the smaller, substandard landfills are making way for larger landfills more in line with best practice. Cooperation among local authorities has helped this process. There is likely to be further opportunity for change when existing resource consents for landfills come up for renewal.
To ensure progress continues the Ministry will:
continue to promote and update the existing guidance for landfill siting, design, operation and closure
review the Landfill Census process to ensure data collection is effective.