Electrochemical Technologies for Removing Petroleum Hydrocarbons from Produced Water
reactions involving O2, Cl2 and H2 evolution. COD reductions of 24% and 48 % were achieved after 70 hours of electrolysis at 10 °C and
25 °C, respectively.
The electrochemical purification of bilge water using Pt/Ir electrodes was investigated by Körbahti and Artut16
(see Table 1). Optimised
conditions under specified constraints were obtained for the highest desirability at 100 % bilge water composition (initial COD = 3,080 mg/l), 50/50 % seawater/fresh water composition, 12.8 mA/cm2 current density and 32 °C reaction temperature, obtaining COD removal figures ranging from 85 to 100 %.
EO and IEO using a boron doped diamond (BDD) anode, EF using an iron electrode and EO using a ruthenium mixed metal oxide (Ru-MMO) electrode were investigated for the treatment of petroleum refinery wastewater by Yavuz et al.17
(see Table 1). Under best operational
conditions, complete phenol and COD removal could be achieved with almost all methods. The most efficient method was EF, followed by EO using a BDD anode. With EF, phenol removal of 98.74 % was achieved in 6 minutes of electrolysis and COD removal of 75.71 % was reached after 9 minutes of electrolysis. With EO using a BDD anode, 99.53 % phenol and 96.04 % COD removal were obtained at a current density of 5 mA/cm2. With IEO, in the presence of 0.05 M NaCl, 98.9 % phenol removal in 60 minutes and 95.48 % COD removal in 90 minutes were reached at a current density of 3 mA/cm2. However, only one application of EO for removing petroleum hydrocarbons from produced water has been reported.
Zanbotto Ramalho et al. studied the anodic oxidation of organic pollutants from produced water generated by petroleum exploration at a Petrobras plant in Brazil using an electrochemical reactor with a Ti/RuO2TiO2SnO2 electrode (see Figure 4).18
Under
galvanostatic conditions (current density = 89 mA/cm2), it was found that the use of different flow rates (0.25, 0.5, 0.8 and 1.3 dm-3 h) allowed to achieve different removal efficiencies of 98 %, 97 %, 95 % and 84 %, respectively. Importantly, under the same conditions, EO process achieved a poor degradation of phenol and
1.
Fakhru’l-Razi A, Pendashteh A, Abdullah LC, et al., Review of technologies for oil and gas produced water treatment, J Hazard Mater, 2009;170(2–3):530–51.
2. United States Environmental Protection Agency website. Available at:
www.epa.gov (accessed October 4, 2011).
3.
Veil JA, Puder MG, Elcock D, Redweik RJ Jr., A white paper describing produced water from production of crude oil, natural gas, and coal bed methane, US Department of Energy, National Energy Technology Laboratory, 2004.
4.
Ekins P, Vanner R, Firebrace J, Zero emissions of oil in water from offshore oil and gas installations: economic and environmental implications, J Clean Prod, 2007;15(13–14):1302–15.
5.
Fillo JP, Koraido SM, Evans JM, Sources, characteristics, and management of produced waters from natural gas production and storage operations. In: Ray JP, Engelhardt FR (eds), Produced Water: Technological/Environmental Issues and Solutions, New York: Plenum Press, 1992;151–62.
6.
Hansen BR, Davies SRH, Review of potential technologies for the removal of dissolved components from produced water: Oil and natural gas production, Chemical Engineering Research and Design, 1994;72(2):176–88.
7. 8.
Rajkumar D, Palanivelu K, Electrochemical treatment of industrial wastewater, J Hazard Mater, 2004;113(1–3):123–9.
Li G, An T, Chen J, et al., Photoelectrocatalytic decontamination of oilfield produced wastewater containing refractory organic pollutants in the presence of high
116
ethyl benzene; that is, 20–47 % (at 0.25, 0.8 and 1.3 dm-3 h) and 17–47 % (at 0.25, 0.5, 0.8 dm-3 h), respectively. Complete elimination of pollutants was obtained after 0.5–2.5 hours of electrolysis, with energy consumption values ranging from 4.84 to 0.97 kWh m-3 and removal prices ranging from 0.28 to 1.41 R$ (reais, the Brazilian currency).
Emerging Electrochemical Treatments
Recently, new emerging electrochemical treatments have received increasing attention. These include EF and photoassisted systems such as PEF and PEC.8,17,23
Li et al. also compared photocatalysis, EO and PEC for the treatment of produced water.23
Results showed that, at equivalent
doses, PEC exhibited the greatest capability to reduce genotoxicity, whereas photocatalysis was the least effective and did not result in an appreciable change in mutagenicity; results of both biological and chemical analysis indicated that PEC was the most effective technology for the degradation of oilfield wastewater. Also, the recent report by Yavuz et al.17
demonstrated the efficiency of EF for
removing organic pollutants from petroleum refinery wastewater (see Table 1).
Concluding Remarks
Electrochemical technologies to remove organic pollutants from produced water have been investigated by a relatively small number of authors. Their findings demonstrate the applicability of electrochemical technologies for the treatment of organic petroleum wastewater, and point to EO and IEO as promising alternatives for organic/inorganic pollutants removal from produced water generated by the petrochemical industries. At the same time, these technologies are suitable for the elimination of several petroleum pollutants from water, under different environmental conditions. Combined electrochemical technologies could be used to reduce the effects of environmental disasters such as the recent Gulf of Mexico oil spill. n
concentration of chloride ions, J Hazard Mater, 2006;138(2):392–400.
9.
Santos MR, Goulart MO, Tonholo J, Zanta CL, The application of electrochemical technology to the remediation of oily wastewater, Chemosphere, 2006;64(3):393–9.
10. Ma H, Wang B, Electrochemical pilot-scale plant for oil field produced wastewater by M/C/Fe electrodes for injection, J Hazard Mater, 2006;132(2–3):237–43.
11. De Lima RM, da Silva Wildhagen GR, da Cunha JW, Afonso JC, Removal of ammonium ion from produced waters in petroleum offshore exploitation by a batch single-stage electrolytic process, J Hazard Mater, 2009;161(2–3):1560–4.
12. Abdelwahab O, Amin NK, El-Ashtoukhy ES, Electrochemical removal of phenol from oil refinery wastewater, J Hazard Mater, 2009;163(2–3):711–6.
13. Tran LH, Drogui P, Mercier G, Blais JF, Electrochemical degradation of polycyclic aromatic hydrocarbons in creosote solution using ruthenium oxide on titanium expanded mesh anode, J Hazard Mater, 2009;164(2–3):1118–29.
14. Tran LH, Drogui P, Mercier G, Blais JF, Coupling extraction- flotation with surfactant and electrochemical degradation for the treatment of PAH contaminated hazardous wastes, J Hazard Mater, 2009;170(2–3):1218–26.
15. Tran LH, Drogui P, Mercier G, Blais JF, Comparison between Fenton oxidation process and electrochemical oxidation for PAH removal from an amphoteric surfactant solution, J Appl Electrochem, 2010;40(8):1493–510.
16. Körbahti BK, Artut K, Electrochemical oil/water demulsification and purification of bilge water using Pt/Ir electrodes, Desalination, 2010;258(1–3):219–28.
17. Yavuz Y, Savas Koparal A, Ögütveren ÜB, Treatment of petroleum refinery wastewater by electrochemical methods. Desalination, 2010;258(1–3):201–5.
18. Zanbotto Ramalho AM, Martínez-Huitle CA, Ribeiro da Silva D, Application of electrochemical technology for removing petroleum hydrocarbons from produced water using a DSA- type anode at different flow rates, Fuel, 2010;89(2):531–4.
19. Rajeshwar K, Ibanez JG, Swain GM, Electrochemistry and the environment, J Appl Electrochem, 1994;24(11):1077–91.
20. Martínez-Huitle CA, Ferro S, Electrochemical oxidation of organic pollutants for the wastewater treatment: direct and indirect processes, Chem Soc Rev, 2006;35(12):1324–40.
21. Martínez-Huitle CA, Brillas E, Decontamination of wastewaters containing synthetic organic dyes by electrochemical methods: A general review. Appl Catal B, 2009;87(3–4):105–45.
22. Woytowich DL, Dalrymple CW, Gilmore FW, Britton MG, Electrocoagulation (CURE) treatment of ship bilgewater for the US coast guards in Alaska. Mar Technol Soc J, 1993;27():62–7.
23. Li G, An T, Nie X, Sheng G, et al., Mutagenicity assessment of produced water during photoelectrocatalytic degradation, Environ Toxicol Chem, 2007;26(3):416–23.
EXPLORATION & PRODUCTION – VOLUME 9 ISSUE 2
Li et al. found that, to remove COD from produced water, the efficiency of PEC was much higher than that of photocatalysis or EO.8
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