Sulfite pretreatment is effective for enhancing the biodegradability of waste activated sludge (WAS). However, the mixture of primary sludge (PS) and WAS is normally collected and treated together, and the effect of sulfite on the sludge mixture remains unclear. Here, we reported that sulfite pretreatment could disintegrate the flocs of the sludge mixture and improve sludge biodegradability. The substrate release from the sludge mixture after sulfite pretreatment (100, 300, and 500 mg SO₃²⁻-S/L) could be enhanced with soluble chemical oxygen demand by up to 1.58 times, soluble nitrogen by up to 1.38 times, soluble polysaccharides by up to 3.04 times and proteins by up to 6.08 times. Further analysis on flocs structure suggests that sulfite may destruct the functional groups of proteins and amino acids and lyse the main structure of sludge cell walls. Moreover, methane production from the sludge mixture could be enhanced by 16% after pretreated by sulfite at 500 mg S/L (i.e., 123.59 CH₄/kg VS_added), whereas the digested sludge volume could be reduced by 1.51 times. Environmental implications suggest that sulfite pretreatment could save sludge treatment costs by 1.06 $/PE/y and reduce CO₂-equivalent emissions by 5.19 kg CO₂/PE/y, demonstrating its potential as a cost-effective and carbon-neutral technology for sludge management.

亚硫酸盐预处理可有效提高废物活性污泥（WAS）的生物降解能力。但是，通常将初级污泥（PS）和WAS的混合物收集并一起处理，并且亚硫酸盐对污泥混合物的影响仍不清楚。在这里，我们报道了亚硫酸盐预处理可以分解污泥混合物的絮凝物并提高污泥的生物降解性。亚硫酸盐预处理（100、300和500 mg SO ₃ ^2-后，污泥混合物中的基质释放-S / L）可以通过增加1.58倍的化学需氧量，增加1.38倍的可溶性氮，增加3.04倍的可溶性多糖和增加6.08倍的蛋白质来提高。对絮凝物结构的进一步分析表明，亚硫酸盐可能破坏蛋白质和氨基酸的官能团，并裂解污泥细胞壁的主要结构。此外，污泥混合物中的甲烷产量在以500 mg S / L（即123.59 CH ₄ / kg V​​S_添加）进行亚硫酸盐预处理后，可提高16％，而消化的污泥量可减少1.51倍。对环境的影响表明，亚硫酸盐预处理可以节省污泥处理成本1.06 $ / PE / y，并减少5.19 kg CO _2的CO ₂当量排放量/ PE / y，展示了其作为污泥管理的经济高效和碳中和技术的潜力。