Due to an increasing awareness of the true economic and environmental cost of conventional landfilling, recent interest has developed in Australia in technologies that accelerate the degradation of the organic fraction of municipal solid waste (MSW). The management of the organic waste stream, which typically makes up 60 to 70% of MSW in Australia, is central to reducing the reliance on landfill space. One option is to digest the organic fraction prior to landfilling, or preserve landfill space by accelerating the decomposition of the organic fraction within the landfill. This paper quantifies the benefits of digestion as a function of the degradation time, t_d. The analysis considers both invessel and landfill-based bioreactor technologies and calculates net economic impact, expressed as $US t⁻¹ MSW, as the sum of enhanced and more rapid biogas retrieval, saved landfill space, reduced environmental disamenity and reduced postclosure costs, minus the capital and operating costs to implement the technology. The benefits, on a per tonne basis, are shown to be insensitive to the size of the waste stream while costs diminish as the waste stream size increases. A conventional landfill with t_d= 20 yr is used as a basis of comparison. At 1800 t day⁻¹, the maximum level of benefit is 13 $US t⁻¹ at t_d= 2 months, diminishing monotonically to zero at t_d= 20 yr. The cost of achieving t_d= 2 months is the cost of invessel digestion, estimated to be 99 $US t⁻¹, resulting in an overall increase of 86 $US t⁻¹ in waste management costs. Similarly, degradation times of 2 < t_d < 5 yr provide a benefit of 8 to 11 $US t⁻¹ for a waste stream of 1800 t day⁻¹. This rate of degradation can be achieved with landfill-based bioreactor technology. The cost of additional infrastructure needed to implement accelerated degradation, such as pretreatment pads, internal leachate distribution networks and additional gas wells and generators, is estimated to be less than 1 $US t⁻¹. Bioreactor technology is therefore appealing, although their is uncertainty about the additional operating costs needed to run a landfill as a bioreactor. Additional operations would mainly revolve around segmenting the waste mass to tightly control leachate distribution. The cost of these additional operations are unlikely to exceed the operating cost of a modern conventional landfill, estimated at 9 $US t⁻¹. Therefore, landfill bioreactor technology should be cost effective.

The MWS model (MIMES/Waste for Sweden) is a systems engineering model for strategic planning of national solid waste management systems. It was developed for Sweden, but the general approach can be applied to other countries as well. The MWS model integrates cost minimization and emissions accounting and is intended for evaluating, from economic and environmental points of view, waste treatment technologies and waste management policies. The potential users of the model are, e.g. government agencies, companies, trade associations and funding authorities. In the MWS model, the Swedish waste management system is represented by 10 generalized municipal waste management systems. The integration of the generalized systems into a national model allows an analysis on a national level as well as on a generalized municipal level. A case study of the Swedish solid waste management system illustrates the application of the MWS model.

In order to comply with the Kyoto Protocol agreements, Israel has to assess all the sources contributing to greenhouse gases (GHG) and analyze the alternative options to reduce these emissions. The waste sector in Israel contributes 13% of total GHG emissions for a time horizon of 100 years (for a time horizon of 20 years, the waste sector contribution equals more than 25% of total GHG emissions). Mitigation options from the waste sector, as well as the costs associated with each alternative, show that the most cost-effective means to treat the degradable organic components of waste is by aerobic composting (investment of less than 10 US$ to reduce emission of 1 t of CO₂ equivalent per year).

The disposal of solid waste is quickly becoming a severely logistic and costly problem in many countries. While Sweden is usually considered to have a fairly successful recycling programme, this varies from region to region. This paper is an initial attempt at characterizing this regional variation. In this study, the recycling behaviour of a representative sample of 1193 individuals from Kiruna, the northern most municipality of Sweden, is investigated. It is observed that the propensity to recycle differs from the results obtained by other studies in different municipalities. Some potential reasons for this are mentioned. The data in this study are analysed using simple descriptive analysis and recycling behavioural models are estimated using logistic regressions. It was found that many socio-economic factors, such as sex, marital status, number of children, type of house one lives in, house ownership, location of where one lives (within town or outside town), size of house, employment status and salary, were not significant in explaining recycling behaviours of most components of wastes.

Semarang, the capital city of the Central Java Province, Indonesia, has been struggling to overcome its municipal solid waste problem. The current waste disposal system covers about 60% of the total waste generated. The paper begins by introducing the solid waste problem in Semarang with particular attention to the Five Year Development Plans. The Adipura program is introduced and recent measures for improving urban infrastructure assessed. The socioeconomic role of scavengers in the waste management process is detailed and the existing solid waste management system in Semarang is critiqued. The paper then introduces the Semarang study area. Waste characteristics are examined and the market value of recyclable materials is estimated at about Rp. 8 billion ($A 3.6 million) per year. The socioeconomic importance of scavengers is recognized in the reduction of domestic solid waste. The final section of the paper recommends that Semarang should consider source separation, home and large-scale composting as a means to deal with its solid waste problem.

The paper describes a laboratory experiment on the biological activity of bacterial populations derived from landfill waste and established on granular materials under conditions similar to those in a landfill drainage system. Two perspex laboratory columns were used to model the landfill drainage system. Artificially formulated leachate was recycled through the columns and the composition of the leachate and the gas produced was measured.

In this work a procedure was optimized to recover Salmonella typhimurium from a vegetable compost after its artificial contamination. A combination of a bacteriological method, immunomagnetic separation (IMS) and polymerase chain reaction (PCR) techniques allowed a reduction in the detection time to 30 h while maintaining high specificity. The lower threshold of direct amplification from extracts of contaminated compost was 10⁸ salmonellae g⁻¹. To improve the sensitivity, a combination of shortened pre-enrichment and enrichment procedures was optimized and the growth of S. typhimurium evaluated. Immunomagnetic separation using anti-Salmonella Dynabeads^TM permitted the recovery of 30 salmonellae per 50 g of compost, the same value obtained with the traditional microbial method, which takes two days longer. Alternative purification methods to reduce organic compound inhibition of the PCR reaction mixture did not improve Salmonella detection under a threshold of 10⁵ salmonellae g⁻¹.

A case study was carried out at an old landfill site (Riet site) located in Winterthur, northern Switzerland. The Riet site contains mainly municipal solid wastes (MSW) comprising four discrete unlined landfill compartments, the oldest of which dates back to 1918. One goal of the case study was to assess the investigative techniques used to determine the risk of groundwater contamination. Waste compartments and leachate plumes were delineated with the electromagnetic method EM31 and with tracer methods. The most efficient methods for a risk assessment were flow modelling based on reliable hydraulic head and hydraulic conductivity measurements, and chemical analyses. Chemical analyses of leachate and groundwater samples showed that the older compartments of the landfill pose only a small risk to the groundwater. The other goal of the study was to determine the long-term risk of groundwater contamination posed by MSW landfills of different ages. To this end, chemical concentrations of leachate from the Riet site were compared with those of other MSW landfills of various ages. The long-term risk of landfill compartments older than about 1960 can be considered in general to be considerably smaller than that of younger ones. Age of the compartment and leachate concentrations could be correlated.

Solid waste management needs to be environmentally sustainable to reduce overall environmental burdens. It also needs to be economically sustainable to be affordable for all sectors of the community served. Integrated waste management (IWM) takes an overall approach to this, involves the use of a range of different treatment options and deals with the entire waste stream. The tool of Life Cycle Inventory (the goal definition and inventory stages of a Life Cycle Assessment) can successfully be applied to integrated waste management systems to assess their environmental burdens. Life Cycle Inventory (LCI) tools for solid waste management have been available for some time. Several models have been developed and applied to both theoretical and actual waste management strategies. This report reviews a case study where a Life Cycle Inventory model was applied in the development of an integrated approach to waste management.