Enhanced dewaterability of waste activated sludge by UV assisted ZVI-PDS oxidation  

作　　者：Yanping Zhang Tiantian Li Jiayu Tian Huichun Zhang Fen Li Jiahua Pei 

机构地区：[1]School of Civil Engineering and Transportation,Hebei University of Technology,Tianjin 300401,China [2]Department of Civil and Environmental Engineering,Case Western Reserve University,Cleveland,OH 44106,USA [3]College of Chemical and Environmental Engineering,Harbin University of Science and Technology,Harbin 150000,China

出　　处：《Journal of Environmental Sciences》2022年第3期152-164,共13页环境科学学报（英文版）

基　　金：This work was supported by the National Natural Science Foundation of China(No.51608166);the China Scholarship Council(No.201906705003).

摘　　要：Ultraviolet(UV)assisted zero-valent iron(ZVI)-activated sodium persulfate(PDS)oxidation(UV-ZVI-PDS)was used to treat waste activated sludge(WAS)in this study.The dewaterability performance and mechanism of WAS dewatering were analyzed.The results showed that UV-ZVI-PDS can obtain better sludge dewatering performance in a wide pH range(2.0-8.0).When the molar ratio of ZVI/PDS was 0.6,UV was 254nm,PDS dosage was 200 mg/g TS(total solid),pH was 6.54,reaction time was 20 min,the CST(capillary suction time)and SRF(specific resistance to filtration)were decreased by 64.0%and 78.2%,respectively.The molar ratio of ZVI/PDS used in this paper is much lower than that of literatures,and the contents of total Fe and Fe^(2+) in sludge supernatant remained at a low level,as 3.7 mg/L and 0.0 mg/L.The analysis of extracellular polymeric substances(EPS),scanning electron microscope(SEM)and particle size distribution showed that the EPS could be effectively destroyed by UV-ZVI-PDS,the sludge flocs broken down into smaller particles,cracks and holes appeared,and then the bound water was released.At the same time,the highly hydrophilic tightly bound-EPS(TB-EPS)were converted into loosely bound EPS(LB-EPS)and soluble EPS(S-EPS).During sludge pretreated by UV-ZVI-PDS,positively charged ions,such as Fe^(2+),Fe^(3+) and H^(+),produced in the reaction system could reduce the electronegativity of sludge surface,promote sludge particles aggregation,and then enhanced the sludge dewaterability.

关 键 词：Sludge dewatering PERSULFATE Zero-valent iron UV Extracellular polymeric substances 

分 类 号：X703[环境科学与工程—环境工程]