Effect of citric acid on extracellular polymeric substances disruption and cell lysis in the waste activated sludge by pH regulation

Xuewei Wu; Xiaoming Li; Qi Yang; Qiuxiang Xu; Ziletao Tao; Xiaoding Huang; You Wu; Lingjuan Tao; Zhoujie Pi; Zhuo Chen; Dongbo Wang

doi:10.1016/j.biortech.2020.122859

Effect of citric acid on extracellular polymeric substances disruption and cell lysis in the waste activated sludge by pH regulation

Bioresour Technol. 2020 Apr:302:122859. doi: 10.1016/j.biortech.2020.122859. Epub 2020 Jan 22.

Authors

Xuewei Wu¹, Xiaoming Li², Qi Yang³, Qiuxiang Xu³, Ziletao Tao³, Xiaoding Huang³, You Wu³, Lingjuan Tao³, Zhoujie Pi³, Zhuo Chen³, Dongbo Wang³

Affiliations

¹ College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China. Electronic address: wuxuewei@hnu.edu.cn.
² College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China. Electronic address: xmli@hnu.edu.cn.
³ College of Environmental Science and Engineering, Hunan University, Changsha 410082, PR China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha 410082, PR China.

PMID: 32018085
DOI: 10.1016/j.biortech.2020.122859

Abstract

This paper investigated the effects of citric acid (CA) on extracellular polymer destruction and cell lysis in sludge at different initial pH by measuring capillary suction time (CST), extracellular polymeric substances (EPS) and intracellular bound water. The results indicated that under CA concentration at 0.05 g/g suspended solids (SS) and initial pH 4, the CST value decreased from 175.5 s to 112.3 s, slime extracellular polymeric substances (S-EPS) and loosely bound EPS (LB-EPS) content respectively to increase from 4.92 to 41.43, 2.27 to 5.49 mg/g volatile suspended solids (Vss), while tightly bound EPS (TB-EPS) content to decrease from 12.35 to 5.01 mg/g (Vss), which suggested CA could disrupt outer EPS effectively. Intracellular bound water content decreased from 1.23 g/g to 0.41 g/g dry solid (DS). As a result, CA could release intracellular bound water effectively, thereby improving sludge dewatering degree.

Keywords: Cell lysis; Citric acid; Deflocculation resistance; Dewaterability; Waste activated sludge.

MeSH terms

Citric Acid
Extracellular Polymeric Substance Matrix
Hydrogen-Ion Concentration
Sewage*
Waste Disposal, Fluid*
Water

Substances

Sewage
Water
Citric Acid