4. Landfill Classification

• Class A landfills meet, or are consistent with, the site selection and design standards outlined in the Centre for Advanced Engineering's Landfill Guidelines (2000). These landfills are sited in areas that reduce the potential for adverse environmental effects, have engineered systems designed to provide a degree of redundancy for leachate containment, and collect landfill leachate and landfill gas. See Appendix D: Landfill Classification - Class A Requirements and Appendix E: Assessing Alternative Solutions for Class A Landfills for help in determining whether a specific landfill can be considered a Class A landfill.

  Minimum requirements: Centre for Advanced Engineering, Landfill Guidelines (2000).

• Class B landfills are existing landfills that do not meet the site selection and design standards outlined in the Centre for Advanced Engineering's Landfill Guidelines (2000) and are consented to accept general domestic and commercial waste. These landfills have limited or no engineered systems designed to collect landfill leachate or gases, and may be in areas that pose a risk to the environment (e.g. sited over highly permeable sands and/or gravels, active faults, or floodplains).

  Minimum requirements: existing resource consent to accept general domestic and commercial waste.

The landfill classification system allows some level of flexibility. For instance, there may not be sufficient low-permeability clay regionally available to allow the cost-effective design of a landfill that is clearly equivalent to the suggested landfill designs outlined in the CAE Landfill Guidelines. However, it may be possible to design the landfill in such a way that it provides a level of containment equivalent to those designs.

Landfills that do not clearly meet the requirements outlined in the CAE Landfill Guidelines have the option of showing that the selected combination of siting and design provide an equivalent level of containment. In all cases, Class A landfills must meet a number of minimum design and siting requirements. These are the criteria in Appendix A where no alternative solutions are provided for.

The decision process for waste acceptance is outlined in Figure 2, but the following points should be noted.

• The landfill classification system applies to municipal waste landfills - it does not include industrial monofills. Waste acceptance criteria for industrial monofills should be determined through the resource consent process under the Resource Management Act 1991.
• Cleanfill sites are covered by the Guide to the Management of Cleanfills and can accept wastes meeting the Ministry's cleanfill definition. Cleanfills should have an existing resource consent to accept cleanfill material, or meet the conditions of a relevant permitted activity rule in a regional plan.
• The majority of existing landfills do not meet the Class A standard, although the majority of refuse in New Zealand is disposed to sites that are likely to meet Class A. The inclusion of Class B acknowledges the existence of older-style tips or landfills and the need to control waste disposal at these sites. It is unlikely that new landfills would be consented unless they meet the Class A landfill standard.
• It is recognised that there is an increasing demand for sites that accept construction and demolition wastes. The acceptable standard for these sites depends on the range of wastes being accepted at the site. In practice this varies widely, and it is recommended that the acceptable standard be developed on a site-by-site basis.

Figure 2: Landfill classification

Figure 2 shows that if a landfill can meet the criteria for Class A landfills and has a consent to accept municipal waste, then it is a Class A landfill. If a landfill cannot meet the criteria for Class A landfills but has a consent to accept municipal waste, then it is a Class B landfill.