Technological characterization and environment-friendly possibilities to reuse water treatment sludge in building materials

Abstract

Water treatment plants (WTPs) produce thousands of tons of sludge annually, which is destined for landfill disposal, an environmentally and economically impractical alternative. Chemical, mineralogical, and morphological characterization besides environmental classification has been performed for WTP sludge and it was evaluated application potential in building materials, from a literature review. The characterization was carried out by X-ray fluorescence spectrometry, X-ray diffraction, scanning electron microscopy analysis, and leaching and solubilization tests. The results show that the presence of activated charcoal residues from water treatment in one type of sludge was of little relevance for changes in the properties of the waste. Both sludges have a wide range of particle sizes, consisting mainly of silica, aluminum and iron oxides, as well as kaolinite, quartz, and iron minerals. Special attention must be paid to the solubilization of metallic contaminants to avoid contamination risks and order to make the application safer and more effective, it is necessary to study deeply ways to inert the WTP sludge. The sludges studied have a high potential for application in ceramic products, mortars, geopolymers and concrete paving stones. Depending on the type of building material, different contents of sludge in natural or calcined state can be incorporated.

Keywords:

• Waste valorization
• building material
• recycling
• reuse of materials

Disclosure statement

No potential competing interests have been reported by the author(s).

Data availability statement

Data and materials will be made available upon request.

Additional information

Funding

The authors thank PRO-ICT/UFFS (proc. PES-2019-0627) for the financial support of the research group. W.M.K. Levandoski and M. Krogel are grateful to the Coordination for the Improvement of Higher Education Personnel (CAPES) and E.P. Korf to the CNPq (PQ-2) for their fellowships.