Sustainable water treatment ceramsite derived from dredged sludge and biomass waste for neutralizing acidic mining wastewater: Mechanisms and efficiency.

Porous ceramsite, a typical water treatment material, could be potentially applied for treating acidic mining wastewater (AMW) with alkaline sources. This study aims to evaluate the treatment efficiency and mechanisms of water treatment ceramsite (WTC) derived from dredged sludge, biomass waste, and alkaline sources for neutralizing AMW. WTC with 8% CaCO was found to effectively increase the pH of AMW to 7 within 60 min, demonstrating its potential for AMW treatment. Mineralogical analysis revealed that the calcium-rich WTC primarily consisted of quartz, feldspar, and lime, with the decomposition of biomass waste during sintering creating a connecting pore structure that enhanced water treatment efficiency. At high temperatures, CaCO decomposed into CaO, the primary alkaline substance responsible for neutralizing AMW. However, excessively high sintering temperatures resulted in increased glassy and feldspar phases, which reduced the reactivity of the ceramsite. This study provides an innovative approach to AMW treatment by transforming solid waste into functional materials, offering a sustainable solution for environmental remediation. The results underscore the potential of WTC as a cost-effective and eco-friendly alternative for mitigating the environmental impacts of mining activities.