Waste containing asbestos and other environmentally problematic substances: Characterization, risks and management

Alessio Boldrin (Editor), Alberto Maresca (Editor), Patrik Fauser (Editor), Hans Sanderson (Editor), Thomas Fruergaard Astrup (Editor)

Research output: Book/ReportReportCommissioned

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Abstract

In Denmark, waste containing asbestos (WCA) is separately collected, handled, and landfilled. Waste contaminated with environmentally problematic substances such as PCBs, PAHs, and heavy metals is also separately collected; incineration is the adopted disposal method for some waste fractions and substances, with landfilling and recycling used only in specific situations. In some cases, besides asbestos, the waste also contains other environmentally problematic substances (e.g., PCBs, PAH, heavy metals) in concentrations exceeding the limit values for hazardous waste. When a combination of waste and other environmentally problematic substances occurs, the waste is likely to be classified as hazardous for multiple reasons. The combined presence of asbestos and other environmentally problematic substances makes managing this type of waste is challenging. While incineration of waste containing asbestos is currently not done in Denmark, the presence of organic substances and heavy metals may limit the possibilities for landfilling. Given the variety of situations (and combination of sub-stances) no general guidelines exist, and Danish municipalities have to make specific decisions on a case-by-case basis.

The objective of this project was to identify and evaluate possibilities for handling waste containing both asbestos and other environmentally problematic substances (WCAPS) in Denmark. The focus was in particular on two potential solutions: i) Landfilling of waste containing asbestos and heavy metals; ii) Thermal treatment of waste containing asbestos and PCB/PAH.

The main objective of the project was achieved through the following specific activities:
•Review of existing literature concerning relevant information and previous assessments of suitable treatment options for asbestos-containing waste.
•Map relevant waste fractions containing asbestos in combination with either i) heavy metals or ii) organic compounds such as PCBs and PAHs, and identify the most important (i.e., largest or more frequently present) at the national level.
•Assess the potential for compliance of the above waste fractions with acceptance criteria for disposal of hazardous waste in accordance with the Landfill regulation, based on laboratory leaching experiments on waste samples containing both asbestos and heavy metals.
•Based on laboratory-scale thermal tests, assess the possible transformation of asbestos fibers and related potential emissions induced by high-temperature conditions.
•Screen the risk of asbestos leaching from landfills to the aquatic environment towards humans (via drinking water) and organisms in the receiving surface waters in Denmark.

About 200 Mton of asbestos have been produced since 1920 up to nowadays. Because of its carcinogenicity, the marketing and use of asbestos-containing products have been banned in the EU since 2006; however, about 2 Mton of asbestos are still produced globally every year. The use of asbestos is linked to a variety of products and applications, most of them related to the construction sector. It is, for example, estimated that, in the 80s, about 70% of asbestos was used in cement products and 10% in vinyl/linoleum flooring.

The generation of waste containing asbestos, originating from products used in the past, is currently in the order of 90,000 ton per year in Denmark. Precise data on the amount of asbestos contained in the waste are not available, but an overall estimate is around 10,000-30,000 ton of asbestos fibers per year. The main treatments for asbestos-containing waste in Denmark are landfilling or exporting for special treatment.

Statistical data about WCAPS are not readily available. Hence Danish municipalities and companies dealing with this type of waste – either demolition or waste handling companies - were contacted to collect information via a questionnaire; 46 municipalities and 8 companies provided a response. While confirming that information is lacking, it was estimated that few hundred ton WCAPS may be generated yearly in Denmark. The most relevant material fractions, either because of frequency or amounts, are:
•Vinyl/linoleum flooring + asbestos + heavy metals;
•Tiles + asbestos + heavy metals;
•Roofing felt + asbestos + organic pollutants.

Experimental activities were carried out to evaluate two potential scenarios for the management of waste containing both asbestos and other environmentally problematic substances:
•“Landfill scenario” focusing on waste samples containing asbestos and relatively high con-tents of heavy metals, to investigate the potential for compliance with the leaching criteria defined for landfilling of hazardous waste;
•“Thermal treatment scenario” focusing on waste samples containing both asbestos and relatively high contents of organic pollutants, to investigate the pontial for destruction of asbestos fibers and organic pollutants at high temperatures.

Four samples of WCAPS - as classified in the respective Environmental Mapping Report (i.e. Miljøkortlægningsrapport) - were obtained from waste management companies and analyzed for their content of asbestos, PCB, PAHs, heavy metals and hydrocarbons. Procedures for screening, mapping and classifying WCAPS were discussed; options for improving the procedures were identified. This included for example:
•the establishment of a coordinated system for recording the occurrence of waste containing both asbestos and other environmentally problematic substances;
•preparation of an official guideline describing how sampling should be done, to ensure objectivity and consistency across municipalities in screening/mapping and the subsequent hazardousness classification;
•implementation of routines so that, for materials known to be potentially inhomogeneous, additional samples are taken and analyzed for the presence of asbestos;
•improvement of material classification strategies by encouraging more sampling of waste materials also during the demolition phase, to cross-check and confirm the results of the mapping phase, and eventually re-classify the waste accordingly.

Samples of tiles and linoleum were tested for compliance with acceptance criteria at hazardous waste landfills. The release tests showed that both materials would comply with the acceptance criteria for all classes of landfills approved for hazardous waste disposal.

Samples of linoleum and roofing felt were treated at 1100 °C, to assess the efficacy of thermal treatment in destroying asbestos and organic pollutants. The results indicated that high temperatures are effective in significantly reducing or eventually almost completely destroying the organic pollutants contained in the waste. With regards to asbestos, results were only available for linoleum flooring (because of the lack of asbestos in the roofing felt samples, despite the fact that their documentation indicated presence). While conclusions beyond the specific samples cannot be made, the experiments indicated that heating of waste to 1100 °C can be effective in destroying the asbestos fibers, in agreement with existing literature on the topic.

The risk screening evaluated leaching of asbestos from landfills to the aquatic environment. The screening indicated that there is low risk towards humans (via drinking water) and organisms in the receiving surface waters. The project further identified that there is no scientific evidence regarding toxicity effects or risks from the combination of asbestos and other contaminants. These finding further support the results obtained via the compliance tests.

Based on the results, potential options for management of the waste evaluated in this project containing both asbestos and other environmentally problematic substances were identified (TABLE 1), together with key parameters to be checked during the decision-process. Regarding the risk screening more knowledge and data on source characteristics, asbestos leaching from waste, exposure and toxicity towards sensitive sub-populations (e.g. children) are required to improve the results. It should be noted that the risk screening is based solely on available data and general assumptions, and specific data collection and stakeholder involvement e.g. for site descriptions was beyond the scope of the project.
Original languageEnglish
PublisherDanish Environmental Protection Agency
Number of pages78
ISBN (Electronic)978-87-7038-454-4
Commissioning bodyThe Danish Environmental Protection Agency
Publication statusPublished - 2022
SeriesMiljøprojekter
Number2216
ISSN0105-3094

Bibliographical note

Environmental Project no. 2216

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