Waste Management & Research: The Journal for a Sustainable Circular Economy

A spreadsheet model for forecasting solid waste tonnages is described. The model uses generation coefficients from the technical literature associated with individual material components (paper, glass, metals, plastics and rubber, organic materials, construction waste, inerts and other) to express the amount of waste produced per capita and per employee in the labor force. Estimates of quantities being generated by two major groups, namely domestic and industrial/commercial/institutional sources are reflected in the model's output. Using this disaggregated format, the model estimates total waste, recaptured waste (as a result of policy initiatives), and net refuse. Confidence intervals are developed using a regression model related to the business cycle. Two worked examples are given for data obtained in Canada.

The issues associated with the statistical analysis of municipal solid waste generation patterns are addressed in this paper. A methodology for determining a mixed probability distribution for daily waste generation data is developed. This methodology is then applied to data from two Canadian municipalities.

This paper shows the possibility of moving in a matter of weeks from mesophilic (37°C) to thermophilic (55°C) conditions in the anaerobic digestion of the organic fraction of municipal solid waste (MSW) at high levels of solids (20%). After the temperature increases, a first pseudo steady-state condition can be reached after a month and a final steady-state condition after 2 months. No particular evidence of digester instability was observed using this approach in changing temperature range. The higher yields obtained in the latter condition (110% larger in terms of specific production) are shown.

In the reprocessing of steel from automotive scrap, lead, cadmium and zinc, which are volatile constituents, vaporize under the extremely high localized temperatures in an electric arc furnace at the points of contact between the graphite electrodes and the charge. These vapors condense to produce a hazardous dust termed electric arc furnace dust (EFD). This study was undertaken to satisfy the need for a mobile system which could be moved from site to site of generators of EFD to avoid transportation of hazardous waste, and to recycle slags and metallic iron products within the plant. A new type of plasma device, the Sustained Shockwave Plasma (SSP) has been developed and tested for treatment of EFD on a laboratory scale (500 g h^-1). Batch tests show that EFD can be treated to produce a non-hazardous slag and metallic zinc and lead to recycle.

Amongst the waste from health care institutions, radioactive waste represents a special category since it cannot be modified or neutralized by any available conventional means. Accordingly, disposal of radioactive waste can mean only its transfer from a place where it represents some hazard to somewhere else where it can be retained without undue risk. Radioactive waste arises in health care institutes as a result of diagnostic, therapeutical or research uses of unsealed radioactive substances. Sometimes, sealed sources withdrawn from further use might also be subject to disposal. Most radionuclides used in medicine are short-lived beta-, or beta-gamma emitters and represent a low risk, if properly handled, that is if due care is taken to prevent significant contamination of the workplace and personnel. Low-activity gaseous and liquid waste can usually be discharged to the environment directly; medium-activity or high-activity waste should be stored for variable periods to allow natural decay before specialized disposal.

This paper presents a review of the different types of radioactive wastes produced in hospitals, and introduces many of the sources of generation and subsequent disposal options. An example is given of the wide range of guidance available, both by national bodies in Hungary and international agencies, such as the International Atomic Energy Agency (IAEA), World Health Organisation (WHO) and International Committee on Radiological Protection (ICRP).

Probably the most important first stage in the development of a new sanitary landfill* is the selection of the site to be used. The inappropriate selection of a site can contribute to the bad image and reputation affecting landfill operations. Landfill site selection is a step-by-step process, in which environmental, engineering and economic criteria are applied successively. Environmental Impact Assessment (EIA) constitutes the first and most crucial stage in this selection process, aiming to quantify the impacts according to the natural characteristics of the sites. A method is presented to facilitate the proper selection of a landfill site for municipal waste. The method follows specific principles, called "selection criteria", the aim of which are to compare the considered sites to a hypothetical "ideal one". As a result the more a site matches the ideal and fulfils the criteria requirements, the more suitable it is as a landfill site. A case study for Athens, Greece is presented in an Appendix.