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Treatment of Drilling Wastewater by Combined Coagulation-Ultraviolet/Fenton-Pressurized Biological Processes |
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| Authors: | Ronghu Lu Guohe Huang Hongyan Zhang Shaohui Guo |
| Affiliation: | 1Associate Professor, Faculty of Chemical Science and Engineering, China Univ. of Petroleum-Beijing, Beijing 102249, China (corresponding author). E-mail: lurh@cup.edu.cn 2Professor, Environmental Systems Engineering Program, Faculty of Engineering, Univ. of Regina, Regina, SK, Canada S4S 0A2. 3Doctor, Dept. of Science and Technology, China Univ. of Political Science and Law, Beijing 102249, China. 4Professor, Faculty of Chemical Science and Engineering, China Univ. of Petroleum-Beijing, Beijing 102249, China. |
| Abstract: | An integrated technique containing coagulation, ultraviolet/Fenton oxidation, and pressurized biological processes was provided for the treatment of wastewater generated from drilling operation where sulfonated muds were used. Ultraviolet/Fenton oxidation process was used to improve biodegradability of effluent after coagulation [assessed through a ratio of biological oxygen demand to chemical oxygen demand (COD) (B/C) index]. Pressurized biological experiments were used to further remove COD so as to meet the wastewater discharge standard. The results showed that coagulation pretreatment could help remove most of CODs (70–80%) in drilling wastewater. A 57% reduction in COD was obtained in the ultraviolet/Fenton oxidation process with 0.8 Qth H2O2 (in 30 min), and the biodegradability was significantly improved (B/C was increased from 0.03 to 0.47). The pressurized biological process could help speed up the reaction process with a saved aeration time of 66.7% under a system pressure of 0.2 MPa (in comparison with the condition of a normal pressure). The overall COD removal efficiency was about 95% and the COD level in the final effluent was less than 100 mg/L, which satisfied the wastewater discharge standard. |
| Keywords: | Wastewater management Muds Coagulation Biological processes |