Background Since July 2002, all waste containing asbestos has been classified as dangerous material. In 2005 this category of mineral was banned entirely across the European Union. This has resulted in an increased load of dangerous waste containing asbestos. The appropriate disposal of asbestos is problematic, and at the time of the project, there was no regulation covering the contamination of landfill leachate by asbestos fibres, and no treatment for their disposal had been developed. Objectives The project aimed to implement a new filtration treatment for asbestos fibres in leachate from hazardous waste landfills. Instead of using the common biological and chemical-physical treatments, which are inadequate for asbestos fibres, an on-site microwave and ultra filtration (MW-UF) pre-treatment was to be set up. The ultra-filtration of the liquid treated with a microwave process effectively blocks fibres and other toxic materials and delivers a liquid depurated (i.e., freed of impurities) of these toxic agents and free of organic matter. The project also hoped to draft analytical methods for quantitative determination of asbestos fibres in leachate (such methods having at the time not yet been standardised). Next, the project would determine the level of danger of such leachate in a particular landfill (Barricalla, Turin), and develop an easily maintainable prototype filtration system capable of retaining 99% of those asbestos fibres with dimensions considered to be dangerous. Results The project successfully developed and implemented a new filtration treatment system for asbestos fibres in leachate from hazardous waste landfills that, instead of using common biological and chemical-physical treatments - deemed as inadequate for asbestos fibres, employs on-site microwave and ultra-filtration pre-treatment. The prototype system – tested on the Barricalla hazardous wastes landfill site near Turin – is able to retain 97% (as opposed to the originally anticipated 99%) of the asbestos fibres and requires little or no maintenance. Additionally, the project staff developed an innovative analytical methodology for quantitative determination of asbestos fibres in leachate. Currently, in the US, laboratory analyses determining fibres in potable water use transmission electron microscopy (TEM). In Italy, prior to the advent of the project, Italian regulations required use of the gravimetric method. Unfortunately, this was totally inadequate for determining asbestos fibres. For airborne fibres, Italian regulations require the use of scanning electron microscopy. Plasma ashing meanwhile had been used for waters containing limited concentrations of organic matter, but nothing had yet been codified for leachate of landfills for hazardous wastes (2C type). The use of a microwave-assisted process was thus innovative in this regard. The results obtained at the 2C type landfill indicated the presence of significant quantities of asbestos in the leachate. This particular landfill contained a wide variety of matter, together with more recent lots that were devoted exclusively to asbestos. In particular, besides a certain amount of fibres with common dimensions, a remarkable number of fibres of smaller lengths and diameters were found. This could be due to the compression and alteration effects of the bulk asbestos material, leading to a progressive micronisation of the fibres. However, documentation of the alteration of the fibres in landfill leachate is very poor, and so further studies of this subject are required in order to assess and address future environmental and sanitary risks. Subsequent to the analytical methodology developed, an analysis was carried out of the risk associated with the management of the asbestos-enriched leachate within landfills. This showed that the concentration of asbestos fibres within leachate (and the associated risk) is more dependent on the status of single landfill lots than on the original amount of asbestos within the wastes. Operational lots where wastes are being disposed, managed, and mechanically moved from one place to another give rise to comparatively asbestos-enriched leachate; completed lots where no activity is taking place any longer give rise to depleted-asbestos leachate, although the wastes disposed there originally contained much more asbestos. The developed filtering system should be just as efficient on other sites, and could be easily reproduced and transferred to any landfill or disposal plant. Filtering the asbestos fibres immediately at the landfill delivers important environmental and economic advantages over performing this step later on in the disposal process, making waste management simpler and safer. The output liquids of the filtering systems to be sent to a disposal plant would already be depurated of a large part of organic matter and hazardous components, making the later treatment steps cheaper. Furthermore, the transportation of such liquids would be safer for the environment. Also, because controlling the level of asbestos contamination at the source is easier than in later stages, the new methodology will discourage unwanted practices such as ad hoc dilution of the liquid. Finally, the outlet liquid from lots dedicated to asbestos could now be safely mixed with liquids coming from other lots.