Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education, China), School of Environmental Science and Technology, Dalian University of Technology, Dalian, China.
State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin, China.
Water Environ Res. 2021 Sep;93(9):1680-1689. doi: 10.1002/wer.1553. Epub 2021 Mar 30.
The efficiency of sludge dewatering is affected by the structure and composition of hydrated extracellular polymeric substances (EPS). Degrading EPS can improve the sludge dewatering performance. As an oxidizing agent, sodium periodate (NaIO ) has ability to oxidize organics, which is expected to decompose the protein and polysaccharide in EPS and improve the efficiency of sludge dewaterability. This study adopted NaIO , for the first time, as an advanced oxidation agent to regulate EPS of waste activated sludge and was combined with anionic polyacrylamide (APAM) as a flocculant to subsequently enhance sludge dewatering. Response surface methodology (RSM) was used to determine the optimal conditions of pH, NaIO , and APAM. The results showed that the composite conditioner's specific resistance of filtration (SRF) and the water content of the vacuum-filtered cake (Wc) were highly enhanced compared with those of the raw sludge (RS) under pH 6.5, a NaIO concentration of 50 mg/g dry solids (DS), and an APAM concentration of 5 mg/g DS. Owing to the pre-oxidation achieved by NaIO under a mildly acid environment, sludge flocs were broken. Subsequently, chemical coagulation (APAM) agglomerated the smaller particles into larger flocs of sludge by adsorption and bridging, thus improving sludge dewaterability. PRACTITIONER POINTS: A novel conditioner, pH/NaIO /APAM, was explored for sludge dewatering. IO • and HO• oxidized extracellular polymeric substances (EPS). Degradation of the protein content of EPS released bound water. Highly enhanced sludge dewaterability was achieved under optimal conditions.
污泥脱水效率受水合细胞外聚合物（EPS）的结构和组成的影响。降解 EPS 可以改善污泥脱水性能。高碘酸钠（NaIO ）作为一种氧化剂，具有氧化有机物的能力，有望分解 EPS 中的蛋白质和多糖，提高污泥脱水效率。本研究首次采用 NaIO 作为高级氧化剂来调节废活性污泥中的 EPS，并与阴离子型聚丙烯酰胺（APAM）结合作为絮凝剂，随后增强污泥脱水。采用响应面法（RSM）确定 pH、NaIO 和 APAM 的最佳条件。结果表明，与原污泥（RS）相比，在 pH 6.5、NaIO 浓度为 50mg/g 干固体（DS）和 APAM 浓度为 5mg/g DS 的条件下，复合调理剂的过滤比阻（SRF）和真空过滤滤饼的含水率（Wc）得到了显著提高。由于 NaIO 在弱酸环境下的预氧化作用，污泥絮体被打破。随后，化学混凝（APAM）通过吸附和桥接作用将较小的颗粒凝聚成较大的污泥絮体，从而提高了污泥的脱水性能。
