Enhanced WWTP effluent organic matter removal in hybrid ozonation-coagulation (HOC) process catalyzed by Al-based coagulant

Xin Jin; Pengkang Jin; Rui Hou; Lei Yang; Xiaochang C Wang

doi:10.1016/j.jhazmat.2016.12.043

Enhanced WWTP effluent organic matter removal in hybrid ozonation-coagulation (HOC) process catalyzed by Al-based coagulant

J Hazard Mater. 2017 Apr 5:327:216-224. doi: 10.1016/j.jhazmat.2016.12.043. Epub 2016 Dec 26.

Authors

Xin Jin¹, Pengkang Jin², Rui Hou¹, Lei Yang³, Xiaochang C Wang⁴

Affiliations

¹ School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, Shaanxi Province, 710055, China.
² School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, Shaanxi Province, 710055, China. Electronic address: pkjin@hotmail.com.
³ Department of Materials Science and Engineering, Monash University, Clayton, VIC, 3800, Australia.
⁴ School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an, Shaanxi Province, 710055, China. Electronic address: xcwang@xauat.edu.cn.

PMID: 28073095
DOI: 10.1016/j.jhazmat.2016.12.043

Abstract

A novel hybrid ozonation-coagulation (HOC) process was developed for application in wastewater reclamation. In this process, ozonation and coagulation occurred simultaneously within a single unit. Compared with the conventional pre-ozonation-coagulation process, the HOC process exhibited much better performance in removing dissolved organic matters. In particular, the maximal organic matters removal efficiency was obtained at the ozone dosage of 1mgO₃/mg DOC at each pH value (pH 5, 7 and 9). In order to interpret the mechanism of the HOC process, ozone decomposition was monitored. The results indicated that ozone decomposed much faster in the HOC process. Moreover, by using the reagent of O₃-resistant hydroxyl radical (OH) probe compound, para-chlorobenzoic acid (pCBA), and electron paramagnetic resonance (EPR) analysis, it was observed that the HOC process generated higher content of OH compared with pre-ozonation process. This indicates that the OH oxidation reaction as the key step can be catalyzed and enhanced by Al-based coagulants and their hydrolyzed products in this developed process. Thus, based on the catalytic effects of Al-based coagulants on ozonation, the HOC process provides a promising alternative to the conventional technology for wastewater reclamation in terms of higher efficiency.

Keywords: Al-based coagulants; Hybrid ozonation-coagulation (HOC) process; Hydroxyl radical generation; Ozonation; Ozone decomposition.