Alum sludge is a typical by-product of drinking water treatment processes. Most sludge is disposed of at landfill sites, and such a disposal method may cause significant environmental concern due to its vast amount. This paper assessed the feasibility of reusing sludge as a supplementary cementitious material, which could efficiently exhaust stockpiled sludge. Specifically, the pozzolanic reactivity of sludge at different temperatures, the reaction mechanism of the sludge–cement binder, and the resistance of sludge-derived mortar to microbially induced corrosion were investigated. The obtained results indicated that 800 °C was the optimal calcination temperature for sludge. Mortar containing sludge up to 30% by weight showed comparable physical properties at a curing age of 90 days. Mortar with 10% cement replaced by sludge can significantly improve the resistance to biogenic corrosion due to the formation of Al-bearing phases with high resistance to acidic media, e.g., Ca₄Al₂O₇·xH₂O and strätlingite.

Graphical abstract

中文翻译：

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明矾污泥价值化生产绿色耐用砂浆

明矾污泥是饮用水处理过程的典型副产品。大多数污泥在垃圾填埋场进行处理，这种处理方法由于其数量巨大，可能会引起重大的环境问题。本文评估了将污泥作为补充胶凝材料进行再利用的可行性，该材料可以有效地排出储存的污泥。具体而言，研究了不同温度下污泥的火山灰反应性、污泥-水泥粘合剂的反应机理以及污泥衍生砂浆对微生物腐蚀的抵抗力。结果表明,800 ℃是污泥的最佳煅烧温度。含有高达 30%（重量）淤泥的砂浆在 90 天的养护期表现出相当的物理特性。₄ Al ₂ O ₇ ·xH ₂ O 和菱镁矿。

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