Abstract Strong water binding ability of extracellular polymeric substances (EPS) and high compressibility of sludge during compression dewatering have greatly hindered the improvement of sludge dewaterability. In this paper, a novel combined conditioning method was proposed to enhance the sludge dewaterability. The sludge was firstly disintegrated by NaCl, then the sludge particles were re-flocculated by cationic polyacrylamide (CPAM), meanwhile the sludge filter cake was modified with rice husk (RH) as filter aid. The results showed that combined NaCl-CPAM-RH conditioning greatly improved the sludge dewaterability compared with that of raw sludge. The optimal NaCl pretreatment lasted 120 min with a dosage of 0.25 mol/L, the optimal CPAM and RH dosage was 30 mg/L and 50 wt%, respectively, which led to a moisture content of sludge cake of 65.44%. The changes of sludge liquid and solid phase conditioned by NaCl-CPAM-RH were analyzed. The NaCl pretreatment disintegrated the sludge floc structure with the release of protein and polysaccharide from EPS and Ca2+ and Mg2+ from sludge flocs to liquid, accompanying with the release of water trapped in sludge matrix. The addition of CPAM and RH reconstructed the sludge flocs with a big mean diameter d(0.5) of 126.84 μm, and the sludge filter cake showed a porous and rigid structure with a porosity increment of 138.62% and a compressibility reduction of 39.62% compared to that of raw sludge.

中文翻译：

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NaCl-阳离子聚丙烯酰胺-稻壳粉联合污泥调理提高污泥脱水能力

摘要 胞外聚合物（EPS）的强水结合能力和压缩脱水过程中污泥的高压缩性极大地阻碍了污泥脱水能力的提高。在本文中，提出了一种新的联合调理方法来提高污泥的脱水能力。污泥先用氯化钠分解，然后用阳离子聚丙烯酰胺（CPAM）使污泥颗粒重新絮凝，同时用稻壳（RH）作为助滤剂对污泥滤饼进行改性。结果表明，与原污泥相比，NaCl-CPAM-RH联合调理大大提高了污泥的脱水能力。NaCl最佳预处理时间为120 min，用量为0.25 mol/L，CPAM和RH的最佳用量分别为30 mg/L和50 wt%，污泥饼含水率为65.44%。分析了NaCl-CPAM-RH条件下污泥液相和固相的变化。NaCl 预处理破坏了污泥絮体结构，EPS 中的蛋白质和多糖以及污泥絮体中的 Ca2+ 和 Mg2+ 释放到液体中，同时释放出困在污泥基质中的水。CPAM和RH的加入重建了平均直径d(0.5)为126.84 μm的污泥絮体，污泥滤饼呈多孔刚性结构，孔隙率增加138.62%，压缩率降低39.62%。生污泥。伴随着被困在污泥基质中的水的释放。CPAM和RH的加入重建了平均直径d(0.5)为126.84 μm的污泥絮体，污泥滤饼呈多孔刚性结构，孔隙率增加138.62%，压缩率降低39.62%。生污泥。伴随着被困在污泥基质中的水的释放。CPAM和RH的加入重建了平均直径d(0.5)为126.84 μm的污泥絮体，污泥滤饼呈多孔刚性结构，孔隙率增加138.62%，压缩率降低39.62%。生污泥。