The treatment and disposal of waste activated sludge (WAS) has become one of the major challenges for the wastewater treatment plants (WWTPs) due to large output, high treatment costs and enriched substantial emerging contaminants (ECs). Therefore, reducing sludge volume, recovering energy and resource from WAS, and removing ECs and decreasing environmental risk have gained increasing attentions. Calcium peroxide (CaO₂), a versatile and safe peroxide, has been widely applied in terms of WAS treatment including sludge dewatering, anaerobic sludge digestion and anaerobic sludge fermentation due to its specific properties such as generating free radicals and alkali, etc., providing supports for sludge reduction, recycling, and risk mitigation. This review outlines comprehensively the recent progresses and breakthroughs of CaO₂ in the fields of sludge treatment. In particular, the relevant mechanisms of CaO₂ enhancing WAS dewaterability, methane production from anaerobic digestion, short-chain fatty acids (SCFA) and hydrogen production from anaerobic fermentation, and the removal of ECs in WAS and role of experiment parameters are systematically elucidated and discussed, respectively. Finally, the knowledge gaps and opportunities in CaO₂-based sludge treatment technologies that need to be focused in the future are prospected. The review presented can supply a theoretical basis and technical reference for the application of CaO₂ for improving the treatment of WAS.

废物活性污泥（WAS）的处理和处置已经成为废水处理厂（WWTP）的主要挑战之一，这是因为其产量高，处理成本高并且富含大量新兴污染物（EC）。因此，减少污泥量，从WAS中回收能源和资源，去除ECs和降低环境风险已引起越来越多的关注。过氧化钙（CaO ₂）是一种通用且安全的过氧化物，由于其产生自由基和碱等特殊性能，已广泛应用于WAS处理中，包括污泥脱水，厌氧污泥消化和厌氧污泥发酵等，为减少污泥提供了支持，回收利用和降低风险。这篇综述全面概述了CaO ₂在污泥处理领域的最新进展和突破。特别是CaO ₂的相关机制分别系统地阐明和讨论了提高WAS脱水性，厌氧消化产生甲烷，短链脂肪酸（SCFA）和厌氧发酵产生氢气，去除WAS中EC的方法和实验参数的作用。最后，展望了未来需要重点关注的基于CaO ₂的污泥处理技术的知识差距和机遇。提出的综述可以为应用CaO ₂改善WAS的治疗提供理论依据和技术参考。