Treatments of asbestos containing wastes

Our plain-English summary of Treatments of asbestos containing wastes, by D. Spasiano, F. Pirozzi (Journal of Environmental Management, 2017).

The study

• Authors: D. Spasiano, F. Pirozzi
• Journal: Journal of Environmental Management
• Published: 2017;204(Pt 1):82-91
• Type of article: Review
• Cited by: 35 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Since the second half of the twentieth century, many studies have indicated inhalation of asbestos fibers as the main cause of deadly diseases including fibrosis and cancer. Consequently, since the beginning of the 80s, many countries started banning production and use of asbestos containing products (ACP), although still present in private and public buildings. Due to some extraordinary catastrophic events and/or the aging of these products, people's health and environmental risk associated with the inhalation of asbestos fibers keeps being high even in those countries where it was banned. For these reasons, many communities are developing plans for an environmental and sanitary safe asbestos removal and management. Asbestos containing wastes (ACW) are usually disposed in controlled landfills, but this practice does not definitively eliminate the problems related with asbestos fiber release and conflicts with the ideas of sustainable land use, recycling, and closing material cycles. Consequently, many scientific papers and patents proposed physical, chemical, and biological treatments aimed to the detoxification of ACW (or the reduction of their health effects) and looking for the adoption of technologies, which allow the reuse of the end-products. By including recent relevant bibliography, this report summarizes the status of the most important and innovative treatments of ACW, providing main operating parameters, advantages, and disadvantages.

Copyright © 2017 Elsevier Ltd. All rights reserved.

In plain English

This article was a review, not a new experiment. The authors, based at two Italian universities, summarized published papers and patents on treating asbestos containing wastes, which are usually placed in controlled landfills, a practice they called only a temporary solution. They covered solidification and stabilization (a pretreatment before landfilling), encapsulation of materials left in buildings, vitrification (melting into glass at 1200 to 1600 degrees Celsius), lower-temperature heat treatments, mechanical milling, chemical treatments with acids or chelating agents, and biological treatments using fungi, lichens and bacteria. They reported, from other studies, that milling turned chrysotile into an amorphous (non-crystalline) material in 4 minutes and crocidolite and amosite in 8 to 12 minutes, that a fungus removed 7.3% of the iron from crocidolite fibers in 20 days, and that a plant in Morcenx, France, opened in 1999 to vitrify asbestos waste. The authors concluded that some treatments already run at industrial or pilot scale but are very expensive compared with landfilling because of high energy use. They judged biological treatment currently unsuitable. It did not study disease in people.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Narrative review of published studies and patents on treatment methods for asbestos containing wastes
• Who was studied: No human or animal population. The review drew on published papers and patents describing physical, chemical and biological treatments of asbestos containing wastes, including pilot and full-scale plants (for example in France and Japan).
• Exposure: Asbestos containing wastes, both friable and non-friable, including cement-asbestos. The fibers discussed were chrysotile, crocidolite, amosite and tremolite. The treatments were solidification and stabilization (described as a pretreatment before landfilling), encapsulation of materials left in place, vitrification, thermal, mechanical, chemical and biological treatments.
• Main results:
  • The review reported a study (Jung et al., 2015) on non-friable asbestos-containing ceiling tiles. Encapsulating the tiles with commercial stabilizers cut airborne asbestos release by 50% compared with untreated tiles under wind of 5 m/s. For damaged tiles, stabilization cut fiber release by 69.5% to 84.4% under wind and vibration.
  • The review reported a laboratory study (Plescia et al., 2003) using a ring mill at 250 rpm. Chrysotile was converted into an amorphous phase in 4 minutes. The amphiboles crocidolite and amosite were converted in 8 to 12 minutes.
  • The review described a large-scale industrial vitrification plant (Inertam) that opened in 1999 in Morcenx, France, to treat asbestos containing wastes.
  • A cost comparison in Table 1, adapted from Balaz and Dutkova (2009), gave a total cost per ton of 239 for mechanical treatment, 146 for thermal treatment and 194 for combined mechano-thermal treatment. The currency symbol is garbled in the text. The authors stated that milling is more expensive than thermal treatment.
  • The review reported a study (Daghino et al., 2006) in which the fungus Verticillium sp., grown in a crocidolite suspension, extracted 7.3% of the iron from the asbestos fibers within 20 days.
  • The authors judged biological treatment of asbestos containing wastes to be currently unsuitable, partly because it does not completely remove asbestos fibers.
• The authors' conclusion: The authors concluded that some alternative treatments are already applied at industrial scale (Inertam, GeoMelt) or pilot scale (the Cordiam process). They found these treatments very expensive compared with landfilling because they require high energy consumption. They said thermal denaturation may be an environmentally friendly alternative to landfilling. They listed barriers still to be overcome: high energy use, large reagent amounts, wastewater, low efficiency of bioremediation, and the fate of end-products.
• Limitations the authors state:
  • The authors noted that the chemical digestion treatments they reviewed were carried out on pure asbestos fibers, while real wastes such as cement-asbestos contain other materials that consume acid.

Topics

Medical terms in this study, explained in our Lexicon: Fibrosis, Fiber Release.

Related studies

• Treatment and recycling of asbestos-cement containing waste — F. Colangelo, R. Cioffi, et al. (2011)
• Classification and management of asbestos-containing waste: European legislation and the Italian experience — F. Paglietti, S. Malinconico, et al. (2016)
• Mechanochemical treatment to recycling asbestos-containing waste — P. Plescia, D. Gizzi, et al. (2003)
• Thermochemical destruction of asbestos-containing roofing slate and the feasibility of using recycled waste sulfuric acid — S.N. Nam, S. Jeong, et al. (2014)
• Sustainable bio-hydrothermal sequencing treatment for asbestos-cement wastes — D. Spasiano, V. Luongo, et al. (2019)
• Dark fermentation process as pretreatment for a sustainable denaturation of asbestos containing wastes — D. Spasiano (2018)

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