TY - JOUR
T1 - Understanding Mechanisms of Synergy between Acidification and Ultrasound Treatments for Activated Sludge Dewatering
T2 - From Bench to Pilot-Scale Investigation
AU - Cai, Mei Qiang
AU - Hu, Jian Qiang
AU - Wells, George
AU - Seo, Youngwoo
AU - Spinney, Richard
AU - Ho, Shih Hsin
AU - Dionysiou, Dionysios D.
AU - Su, Jie
AU - Xiao, Ruiyang
AU - Wei, Zongsu
N1 - Funding Information:
This work was supported by the National Natural Science Foundation of China (No. 2167070159 and No. 21507167) and Zhejiang Provincial Natural Science Foundation of China (LY16B050001).
Publisher Copyright:
© 2018 American Chemical Society.
PY - 2018/4/3
Y1 - 2018/4/3
N2 - Enhancing activated sludge dewaterability is of scientific and engineering importance in the face of accelerated urbanization and stringent environmental regulations. In this study, we investigated the integration of acidification and ultrasound (A/US) treatment for improving sludge dewaterability at both bench- and pilot-scales. Our results showed that the A/US process exhibited significantly improved sludge dewatering performance, characterized by capillary suction time, cake moisture, and water/solid content of sludge cake. Synergistic dewatering mechanisms were elucidated with a suite of macro and spectroscopic evidence. Characterization of treated sludge revealed that US-induced thermal, mechanical shearing force, and radical oxidation effects disrupts floc cells and accelerates the decomposition of extracellular polymeric substances (EPS), releasing bound water into the bulk phase. In addition to enhancing hydrolysis of EPS, the acidic pH environment caused the protonation of functional groups on EPS, facilitating the reflocculation of US decomposed sludge for improved filterability. Our bench-scale and pilot-scale investigations provide a mechanistic basis for better understanding of the A/US process, and enable development of a viable and economical dewatering technology.
AB - Enhancing activated sludge dewaterability is of scientific and engineering importance in the face of accelerated urbanization and stringent environmental regulations. In this study, we investigated the integration of acidification and ultrasound (A/US) treatment for improving sludge dewaterability at both bench- and pilot-scales. Our results showed that the A/US process exhibited significantly improved sludge dewatering performance, characterized by capillary suction time, cake moisture, and water/solid content of sludge cake. Synergistic dewatering mechanisms were elucidated with a suite of macro and spectroscopic evidence. Characterization of treated sludge revealed that US-induced thermal, mechanical shearing force, and radical oxidation effects disrupts floc cells and accelerates the decomposition of extracellular polymeric substances (EPS), releasing bound water into the bulk phase. In addition to enhancing hydrolysis of EPS, the acidic pH environment caused the protonation of functional groups on EPS, facilitating the reflocculation of US decomposed sludge for improved filterability. Our bench-scale and pilot-scale investigations provide a mechanistic basis for better understanding of the A/US process, and enable development of a viable and economical dewatering technology.
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U2 - 10.1021/acs.est.8b00310
DO - 10.1021/acs.est.8b00310
M3 - Article
C2 - 29518313
AN - SCOPUS:85044992003
VL - 52
SP - 4313
EP - 4323
JO - Environmental Science & Technology
JF - Environmental Science & Technology
SN - 0013-936X
IS - 7
ER -