LIQianyi,WANGJing,JIXiaopeng,et al.Sludge Deep Dewatering through Combined Conditioning with Surfactants and Coagulants[J].China Water & Wastewater,2026,42(7):113-121.
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Sludge Deep Dewatering through Combined Conditioning with Surfactants and Coagulants

China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU] volume: 第42卷 Number: 第7期 Page: 113-121 Column: Date of publication: 2026-04-01
Author(s):
LI　Qianyi1;  WANG　Jing2;  JI　Xiaopeng2;  LIN　Hong1;  QIU　Tao2;  ZENG　Hao2;  ZHOU　Jian1
（1. Key Laboratory of the Three Gorges Reservoir Region’s Eco-Environment ， Chongqing University， Chongqing 400045， China； 2. Chongqing Drainage Co. Ltd.， Chongqing 400012， China）
Keywords:
sludge deep dewatering;  conditioning;  surfactant;  coagulant;  extracellular polymeric substances (EPS)
Abstract:
This study addressed the low efficiency of sludge dewatering in current wastewater treatment plants, aiming for sludge deep dewatering (moisture content≤60%). A combined conditioning technology using surfactants and coagulants was developed, focusing on the impact of the combined conditioning agents on sludge dewatering efficiency and their underlying mechanisms. The results demonstrated that the combination of anionic surfactant sodium dodecyl sulfate (SDS), cationic surfactant cetyl trimethyl ammonium bromide (CTAB), and coagulant polyaluminum chloride (PAC), as well as polyacrylamide (PAM), significantly improved sludge dewaterability. Under optimal dosages of 250 mg/gDS for CTAB, 20 mg/gDS for SDS, 80 mg/gDS for PAC, and 5 mg/gDS for PAM, the moisture content of the sludge cake decreased to 57.06%. The specific resistance to filtration reduced from 7.19×1012 m/kg to 2.61×1012 m/kg. The Zeta potential, contact angle, and median particle size of the sludge improved from -17.49 mV, 63.94°, and 26.4 μm to 1.07 mV, 104.81°, and 62.9 μm, respectively. The effective extraction of proteins and polysaccharides from the extracellular polymeric substances (EPS) of the sludge led to a substantial release of tryptophan, tyrosine, and other substances from TB-EPS to S-EPS, resulting in the liberation of a significant amount of bound water. The bound water content decreased markedly from 2.17 g/gDS to 0.90 g/gDS. The combination of CTAB with SDS and PAC with PAM exhibited synergistic effects, significantly altering the secondary structure composition of sludge proteins, leading to a more dispersed protein structure and enhanced hydrophobicity of EPS.
Last Update: 2026-04-01