Aluminium-Bearing Technogenic Wastes as Precursors of Coagulants and Sorbents for Wastewater Treatment: A Critical Review and the Valorisation Potential of a Sulfate-Rich Aluminium Sludge
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Aluminium-bearing technogenic wastes -drinking-water treatment residuals (WTR/alum sludge), primary and secondary aluminium dross and salt cake, anodising sludge, and scrap aluminium -are generated in millions of tonnes annually and are overwhelmingly landfilled. Because aluminium is simultaneously the active element of the most widely used coagulants and the structural element of one of the most effective anion sorbents, these wastes are, in principle, a secondary raw material for water treatment reagents. This paper reviews the published experimental evidence on that conversion and then tests it against the composition of a specific aluminium-rich technogenic sludge collected in the Navoi region of Uzbekistan. Fifty-six peer-reviewed sources indexed in Scopus/Web of Science, published mainly between 2014 and 2026, were screened and analysed. The analysis is deliberately limited to what the X-ray fluorescence data can support; mineralogical, leaching, toxicological and jar-test verification are identified as mandatory next steps.
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