Removal of CX3R-type disinfection by-product precursors from rainwater with conventional drinking water treatment processes

Jijie He; Minghao Shi; Feifei Wang; Youli Duan; Tiantao Zhao; Shihu Shu; Wenhai Chu

doi:10.1016/j.watres.2020.116099

Removal of CX₃R-type disinfection by-product precursors from rainwater with conventional drinking water treatment processes

Water Res. 2020 Oct 15:185:116099. doi: 10.1016/j.watres.2020.116099. Epub 2020 Jul 23.

Authors

Jijie He¹, Minghao Shi¹, Feifei Wang², Youli Duan³, Tiantao Zhao⁴, Shihu Shu⁵, Wenhai Chu⁶

Affiliations

¹ State Key Laboratory of Pollution Control and Resources Reuse, National Centre for International Research of Sustainable Urban Water System, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China; School of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing, 400054, China.
² School of Environmental and Chemical Engineering, Shanghai University, Shanghai, 200444, China.
³ Shanghai Leeya Ecological Engineering Co., Ltd, Shanghai, 200241, China.
⁴ School of Chemistry and Chemical Engineering, Chongqing University of Technology, Chongqing, 400054, China.
⁵ College of Environmental Science and Engineering, Donghua University, Shanghai, 201620, China.
⁶ State Key Laboratory of Pollution Control and Resources Reuse, National Centre for International Research of Sustainable Urban Water System, College of Environmental Science and Engineering, Tongji University, Shanghai, 200092, China; Shanghai Institute of Pollution Control and Ecological Security, Shanghai, 200092, China. Electronic address: 1world1water@tongji.edu.cn.

PMID: 32739696
DOI: 10.1016/j.watres.2020.116099

Abstract

In addition to surface water and groundwater, rainwater is used as an important drinking water source in many parts of the world, especially in areas with serious water pollution or insufficient water resources. Conventional drinking water treatment technologies can remove dissolved organic matter and therefore reduce the formation of disinfection by-products (DBPs) during subsequent disinfection using surface water or groundwater as drinking water sources. However, little information has been known about the effect of conventional water treatment processes on DBP formation when rainwater is used as drinking water source. This study evaluated CX₃R-type DBP precursors removal from rainwater by conventional drinking water treatments and the corresponding decrease of CX₃R-type DBP (trihalomethanes (THMs), haloaldehydes (HALs), haloacetonitriles (HANs) and haloacetamides (HAMs)) formation and toxicity during the subsequent chlor(am)ination. The result showed that both sand filtration (SF) and activated carbon filtration (GAC) were able to remove DBP precursors and GAC outperformed SF, but no DBP precursors removal was observed during coagulation-sedimentation treatment. Among all treatments, SF + GAC was the most effective for DBP precursors removal, with removal efficiencies of 64.2% DOC, 98% DON and 76.6% UV₂₅₄. Correspondingly, both SF and GAC decreased the formation of THMs, HALs, HANs and HAMs, and GAC performed better than SF. The combination of SF and GAC, especially SF + GAC, greatly decreased DBP formation, with average reduction of 79.2% and 85% during chlorination and chloramination respectively. After different treatments, the comprehensive toxicity risk of CX₃R-type DBPs was all reduced, among which GAC + SF exhibited superior performance. Generally, the main contribution of integrated toxicity was HANs during chlor(am)ination. The formation potential of THMs, HALs, HANs and HAMs and the corresponding integrated toxicity were greater during chlorination than that during chloramination. Therefore, the combination of GAC and chloramination was promising in mitigating the comprehensive toxicity risk of THMs, HALs, HANs and HAMs for rainwater.

Keywords: Activated carbon filtration; Coagulation-sedimentation; Disinfection by-products; Rainwater; Sand filtration.

MeSH terms

Chlorine
Disinfectants* / analysis
Disinfection
Drinking Water*
Halogenation
Trihalomethanes
Water Pollutants, Chemical* / analysis
Water Purification*

Substances

Disinfectants
Drinking Water
Trihalomethanes
Water Pollutants, Chemical
Chlorine