Appendix C: Proposed Landfill Gas Collection and Destruction Standard - Fact Sheet

October 2003

Introduction

The Ministry for the Environment is developing a package of national environmental standards. These standards aim to:

create a level playing field for all those involved in resource management
provide certainty and consistency throughout New Zealand
guarantee a level of protection for all New Zealanders.

This information sheet summarises the proposed landfill gas collection and destruction standard and the reason for its development.

Background

The Government considers that the effects of greenhouse gas emissions on climate change are of national importance and accordingly need to be addressed by national mechanisms. The recently introduced Resource Management (Energy and Climate Change) Amendment Bill proposes changes to the Resource Management Act 1991 to preclude regional councils from applying local controls on the discharge of such gases from industrial and trade premises, except when undertaken to administer or give effect to a related regulation such as a national environmental standard.

The waste industry is a relatively minor methane emitter that currently contributes approximately four percent to New Zealand's overall greenhouse gas emissions. When preparing the Government's preferred policy package on climate change the waste industry was excluded from potential emission charges. Instead, the Government chose to promote best-practice through The New Zealand Waste Strategy.

The New Zealand Waste Strategy acknowledges the potential that instruments such as national environmental standards offer. A standard controlling the emission of methane from landfills provides the opportunity to set nationally consistent controls throughout the country that will help ensure that the estimated reduction of 5 Mt of CO2 equivalents from the waste sector is achieved (source: Climate Change - The Government's Preferred Policy Package, April 2002, page 8). As well as reducing the effects on climate change such a standard would address odour and explosive potential related to methane management at landfills.

Proposal

The objective of the proposed standard is to ensure that current best practice landfill gas management for greenhouse gas issues continues. We also aim to provide flexibility to encourage organic waste diversion.

The standard would require landfill gas collection and destruction, with the flaring of gas likely to be the most common option. Beneficial uses of methane such as electricity generation would be permissible provided the landfill owner can demonstrate equivalent or better mitigation of methane gas emissions. The following summarises features of the draft standard for consultation purposes:

Apply to operational landfills that accept municipal solid waste

It would not apply to sites that accept only cleanfill (soil and rubble) or construction and demolition landfill sites - these sites accept negligible amounts of organic matter.

Apply to landfills that are designed to accept over 1 million tonnes of refuse throughout their design life

Installing gas collection systems at landfills smaller than this threshold is not likely to be economically viable.

Apply to sites that are currently operating

It would not apply to existing closed landfills. It is expected that existing gas management control systems at closed landfills will continue to operate as per existing consent conditions.

Apply to proposed sites immediately

Note, however, that in practice gas collection systems are generally not installed until adequate methane generation is occurring. This is dependent on the period of time the refuse has been in place and the total quantity of refuse. This varies but is usually between 80-260 days after refuse placement begins and approximately 200,000 tonnes respectively.

Apply to existing operational sites after a transitional period of three years if a site does not currently have a landfill gas collection system

This provides time for the landfill owner to fund, design and install a landfill gas collection system.

Specify flaring standards based on international best practice. This would include a minimum flare temperature of 750 degrees centigrade for a resonance time of 0.5 seconds

Conditions would also address flame arrestors and backflow protection devices to prevent flash back and landfill fires, plus a flame detector with an automatic slam shut valve and blower isolation to prevent unburnt discharges of landfill gas.

Specify a methane emission limit at the landfill surface and at monitoring points around the landfill

Gas collection efficiencies are variable and therefore measurements are relatively inaccurate and unreliable. It is therefore not possible for the standard to specify a gas collection system percent efficiency. Measuring methane emissions at the landfill surface and at monitoring points around the landfill is currently common practice in resource consent conditions at major landfills including many recently closed sites. The limit is commonly 1% methane (by volume in air) corresponding to approximately 25% of the lower explosive limit. We recommend that this be adopted as the draft methane emission limit for the consultation process.

There may be situations where a landfill exceeds the refuse quantity threshold of 1 million tonnes but through the effective diversion of organic matter, or shallow landfill cells, methane emissions are below the surface methane emission limit

In this case effective operation of a methane collection and destruction system may not be warranted or feasible. This could occur at sites with waste quantities close to the proposed threshold, sites with a shallow depth of refuse, dry sites, or those where organic waste diversion has resulted in a reduction in methane generation.

Implementation

Regional councils will be required to place consent conditions requiring the installation of a landfill gas collection and destruction system on any resource consent granted for landfills with a projected total capacity of over 1 million tonnes, unless the applicant can demonstrate that they will be able to limit surface methane emissions below the performance limit specified by this standard.

The standard will require a review of consent conditions for existing landfills that have a proposed total capacity of over 1 million tonnes within three years after the introduction of the standard.

Estimated impact of the proposal

The proposed standard reflects current best practice in New Zealand and other developed countries. This is confirmed for New Zealand through the findings of the Ministry for the Environment's 2002 Landfill Review and Audit. On this basis we estimate that 20 of New Zealand's 116 currently operating landfills exceed the 1 million tonne threshold. Of these:

three will be closed within the next three years and therefore under the proposed transitional period would not be required to install a gas collection system
seven currently collect and destruct landfill gas
two are planning to install systems but have not yet placed enough waste to generate adequate gas volumes
three sites are designing systems
two sites have systems installed that are currently not operating.
the remaining three landfill sites might be required to design and construct a landfill gas and destruction system, or apply for dispensation through methane surface emission performance, as a result of the standard.

Want to know more?

Contact the Ministry for the Environment by phoning (04) 917 7400, emailing standards@mfe.govt.nz, or see our website: www.mfe.govt.nz.