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 VSadded), 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.

中文翻译：

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亚硫酸盐预处理提高了初级污泥和废活性污泥的生物降解性，以实现具有成本效益的碳中和污泥处理


亚硫酸盐预处理可有效提高废弃活性污泥 （WAS） 的生物降解性。然而，初级污泥 （PS） 和 WAS 的混合物通常一起收集和处理，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。亚硫酸盐预处理后（100、300 和 500 mg SO32−-S/L）后污泥混合物中释放的底物可增加高达 1.58 倍，可溶性氮高达 1.38 倍，可溶性多糖高达 3.04 倍，蛋白质高达 6.08 倍。对絮凝体结构的进一步分析表明，亚硫酸盐可能会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，经 500 mg S/L 亚硫酸盐预处理后，污泥混合物中的甲烷产量可增加 16%（即 123.59 CH4/kg VS添加），而消化后的污泥体积可减少 1.51 倍。环境影响表明，亚硫酸盐预处理可以节省 1.06 美元/PE/年，并减少 5.19 公斤 CO2/PE/年的二氧化碳当量排放，展示了其作为一种具有成本效益和碳中和的污泥管理技术的潜力。