International Review of Waste Management Policy - Department of ...

838
29/09/09
• A per tonne levy for landfilling of waste at conventional landfills; and
• A lower levy rate for landfilling of waste at landfills designed so as to
minimise the unoxidised methane escaping from the landfill (through use
of, for example, passive oxidation layers). The specification of this type of
landfill cell would need to take place under the auspices of the EPA, but it
would allow for additional environmental benefits to be gained from the
overall treatment process. 1047
As will become clear below, we expect that the latter landfill type would become more
common over time.
It is crucial that the levy for stabilised waste is linked to a standard for assessing the
stability of waste. Like the EPA Consultation Guidance, we recommend using the
standard set in the EU Working Document on Biological Treatment of Biowaste 2 nd
Draft: 1048
‘stabilisation’ means the reduction of the decomposition properties of
biowaste to such an extent that offensive odours are minimised and that
either the Respiration Activity after four days (AT4) is below 10 mg O2/g dm or
the Dynamic Respiration Index is below 1,000 mg O2/kg VS/h
This is for the simple reason that the measure needs to be agreed quickly (to give
effect to the levy) and experience from the UK suggests that deliberation on this
measurement can lead to unfamiliar measurement approaches which make it
impossible for developers to know how their technology will fare under a given
measurement method.
Meetings with the EPA suggest that in the Final Version of the Guidance, the stability
criterion might be changed over time, dropping from 10 mg O2 / g dm to 7mg O2 /g
dm, the latter being the Austrian standard (see 52.2.4). We question the rationale for
moving from one standard to the other for the following reasons:
1. The difference in environmental performance is likely to be insignificant, yet
the impact on costs might be significant. The benefit relative to the cost would
appear to be unjustified.
2. The effects on the capacity of a facility effectively change when the stability
criterion changes (and this is equivalent to the effect on costs mentioned
above). This is the lesson of the German experience, where some stabilisation
facilities, which used to operate as double duty sites, had to shut down the
composting side of the plant because the capacity of facilities was
1047 When stabilised waste is landfilled, then to the extent that it is properly stabilised in line with an
appropriate threshold value, the aim is not so much to capture gas for energy generation. Rather, the
objective is to deal with the much reduced fluxes of methane in such a way that they are not emitted to
the atmosphere as methane, and passive oxidation at the landfill surface offers the potential to
achieve this as long as the methane fluxes through the surface are sufficiently low (allowing oxidation
through the surface).
1048 EPA (2008) Municipal Solid Waste - Pre-treatment and Residuals Management: An EPA Technical
Guidance Document, Consultation Draft, Johnstown Castle Estate: EPA.