An advanced treatment process for 3-high wastewater discharged from crude oil storage tanks

• Published in: Environmental science and pollution research international 2023-09, Vol.30 (42), p.95875-95891
• Main Authors: Li, Xue-Wen, Cui, Zhong-Yi, Zhao, Bao-Fu, Wang, Jin-An, Song, Yue-Qin, Zhou, Xiao-Long
• Format: Article
• Language: English
• Subjects: Activated carbon; Activated carbon adsorption; Aeration; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Chemical oxygen demand; Coagulation; Crude oil; Discharge; Earth and Environmental Science; Ecotoxicology; Effluents; Environment; Environmental Chemistry; Environmental Health; Ferrous ions; Filtration; Fouling; Ions; Ions - analysis; Iron; Iron - analysis; Manganese; Membrane processes; Membranes; Membranes, Artificial; Metal concentrations; Microfiltration; Oil; Organic compounds; Organic matter; Osmosis; Oxidation; Petroleum - analysis; Pretreatment; Research Article; Reverse osmosis; Sand filters; Storage tanks; Waste Disposal, Fluid; Waste Water Technology; Wastewater; Wastewater discharges; Wastewater treatment; Water Management; Water Pollution Control; Water Purification
• ISSN: 1614-7499; 0944-1344; 1614-7499
• DOI: 10.1007/s11356-023-29086-4

The wastewater discharged from crude oil storage tanks (WCOST) contains high concentrations of salt and metal iron ions, and high chemical oxygen demand (COD). It belongs to “3-high” wastewater, which is difficult for purification. In this study, WCOST treatments were comparatively investigated via an advanced pretreatment and the traditional coagulation–microfiltration (CMF) processes. After WCOST was purified through the conventional CMF process, fouling occurred in the microfiltration (MF) membrane, which is rather harmful to the following reverse osmosis (RO) membrane unit, and the effluent featured high COD and UV254 values. The analysis confirmed that the MF fouling was due to the oxidation of ferrous ions, and the high COD and UV254 values were mainly attributable to the organic compounds with small molecular sizes, including aromatic-like and fulvic-like compounds. After the pretreatment of the advanced process consisting of aeration, manganese sand filtration, and activated carbon adsorption in combination with CMF process, the removal efficiencies of organic matter and total iron ions reached 97.3% and 99.8%, respectively. All the water indexes of the effluent, after treatment by the advanced multi-unit process, meet well the corresponding standard. The advanced pretreatment process reported herein displayed a great potential for alleviating the MF membrane fouling and enhanced the lifetime of the RO membrane system in the 3-high WCOST treatment. Graphical abstract