Biological treatment of asbestos cement wastes by Aspergillus niger and Acidithiobacillus thiooxidans

Abstract

Asbestos cement materials used in the past by the building construction sector still poses environmental problems, requiring proper treatment and storage. Here we investigated an alternative microbiological-induced treatment of raw chrysotile and asbestos cement materials. Based on the knowledge that some microorganisms, such as Aspergillus niger (fungus) and Acidithiobacillus thiooxidans (bacteria) are potential organic or inorganic acid producers, we evaluated the dissolution of the chrysotile structure, which is the toxic component in these materials, under submerged and solid-state cultivation conditions. The Mg, and Ca release percentage evaluated and SEM/EDX, XRD, and FTIR characterization data have shown a high potential of both microorganisms studied to total chrysotile degradation (up to 100%, based on Mg content), using either the microbial filtrate, submerged and solid-state cultivation. The present study is a potential biological treatment of asbestos cement materials that can also be applied in situ in areas contaminated with asbestos, which is an alternative not applied to energy-intensive methods such as mechanochemical or thermal treatment.