Influences of integrated coagulation-ozonation pretreatment on the characteristics of dissolved organic pollutants (DOPs) of heavy oil electric desalting wastewaters

Huangfan Ye; Baiyu Yang; Qinghong Wang; Zuo Tong How; Chunmei Nie; Pamela Chelme-Ayala; Shaohui Guo; Chunmao Chen; Mohamed Gamal El-Din

doi:10.1016/j.jenvman.2021.113756

Influences of integrated coagulation-ozonation pretreatment on the characteristics of dissolved organic pollutants (DOPs) of heavy oil electric desalting wastewaters

J Environ Manage. 2021 Dec 15:300:113756. doi: 10.1016/j.jenvman.2021.113756. Epub 2021 Sep 14.

Authors

Huangfan Ye¹, Baiyu Yang¹, Qinghong Wang¹, Zuo Tong How², Chunmei Nie³, Pamela Chelme-Ayala², Shaohui Guo¹, Chunmao Chen⁴, Mohamed Gamal El-Din⁵

Affiliations

¹ State Key Laboratory of Heavy Oil Processing, Beijing Key Laboratory of Oil and Gas Pollution Control, China University of Petroleum-Beijing, Beijing, 102249, China.
² Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta, T6G 1H9, Canada.
³ Refining & Petrochemical Research Institute, PetroChina Karamay Petrochemical Co., Ltd., Karamay, 834000, China.
⁴ State Key Laboratory of Heavy Oil Processing, Beijing Key Laboratory of Oil and Gas Pollution Control, China University of Petroleum-Beijing, Beijing, 102249, China. Electronic address: c.chen@cup.edu.cn.
⁵ Department of Civil and Environmental Engineering, University of Alberta, Edmonton, Alberta, T6G 1H9, Canada. Electronic address: mgamalel-din@ualberta.ca.

PMID: 34534758
DOI: 10.1016/j.jenvman.2021.113756

Abstract

The quality of heavy oil electric desalting wastewaters (HO-EDWs) affects the effectiveness of refinery wastewater treatment plants. In this study, an integrated coagulation-ozonation (ICO) process was used to pretreat HO-EDWs and the influences on the characteristics of dissolved organic pollutants (DOPs) were investigated. Coagulation using aluminum sulfate removed 39% of soluble chemical oxygen demand (SCOD), 21% of dissolved organic carbon (DOC), 57% of petroleum hydrocarbons and 38% of polar oils from Liaohe HO-EDWs and the biodegradability was greatly improved. Ozonation removed 33% of SCOD and 88% of polar oils from the coagulated HO-EDWs. Most species of aromatic compounds, phenols, aliphatic acids, anilines and naphthenic acids with high C numbers and ring numbers were degraded and the unsaturation degrees of DOPs significantly decreased under ozonation. As a result, the biodegradability was further improved and the acute toxicity towards Vibrio fischeri was substantially reduced. Some O_xS₁ species and organic nitrogen compounds in HO-EDWs were penetrated through ozonation and caused the residual biotoxicity. The results demonstrate the potential of ICO pretreatment for improving the quality of refractory HO-EDWs.

Keywords: Coagulation-ozonation; Electric desalting wastewaters; Heavy oils; Molecular compositions; Toxicity.

MeSH terms

Environmental Pollutants*
Oils
Ozone*
Wastewater
Water Pollutants, Chemical* / analysis

Substances

Environmental Pollutants
Oils
Waste Water
Water Pollutants, Chemical
Ozone