A new economic instrument for financing accelerated landfill aftercare.

The key aspects of landfill operation that remain unresolved are the extended timescale and uncertain funding of the post-closure period. This paper reviews the topic and proposes an economic instrument to resolve the unsustainable nature of the current situation. Unsustainability arises from the sluggish degradation of organic material and also the slow flushing of potential pollutants that is exacerbated by low-permeability capping. A landfill tax or aftercare provision rebate is proposed as an economic instrument to encourage operators to actively advance the stabilization of landfilled waste. The rebate could be accommodated within existing regulatory and tax regimes and would be paid for: (i) every tonne of nitrogen (or other agreed leachate marker) whose removal is advanced via the accelerated production and extraction of leachate; (ii) every tonne of non-commercially viable carbon removed via landfill gas collection and treatment. The rebates would be set at a level that would make it financially attractive to operators and would encourage measures such as leachate recirculation, in situ aeration, and enhanced flushing. Illustrative calculations suggest that a maximum rebate of up to ∼€50/tonne MSW would provide an adequate incentive.

Management of municipal solid waste incineration residues.

The management of residues from thermal waste treatment is an integral part of waste management systems. The primary goal of managing incineration residues is to prevent any impact on our health or environment caused by unacceptable particulate, gaseous and/or solute emissions. This paper provides insight into the most important measures for putting this requirement into practice. It also offers an overview of the factors and processes affecting these mitigating measures as well as the short- and long-term behavior of residues from thermal waste treatment under different scenarios. General conditions affecting the emission rate of salts and metals are shown as well as factors relevant to mitigating measures or sources of gaseous emissions.

Development of a quick leaching test for monolithic materials by using factorial design.

A quick leaching test procedure for monolithic waste materials has been developed by a Nordic expert group using experimental factorial design. The Dutch quick leaching test proposal in which the wetting time of the test specimen is reduced by applying vacuum was chosen as a starting point. The influence of the following parameters were studied: vacuum, stirring, open or closed vessel, water renewal frequency, leachant quality and laboratory or batch differences. The study was performed with test specimens prepared from a cement stabilised soil containing As, Cr and Cu. The test specimens were immersed in water and the water was renewed at certain time intervals. The study clearly showed that the use of vacuum had a strong effect on the release rate and that the open vessel lowered the pH-values of the eluates due to uptake of carbon dioxide in the water. The results also indicate higher emissions when stirring was applied. The following test conditions are recommended: application of vacuum prior to testing, use of closed test vessel, use of stirring, a test time of 3 days with four water renewals after 15 min vacuum steps, and then after e.g. 2 h, 23 h and 3.2 days, use of demineralised water as leachant. The amount of water must be selected according to the size of the test specimen. A liquid to surface (L/A) ratio of 5-10 ml cm(-2) is recommended. All four eluates collected are filtered and analysed.