Biological treatment of produced water in a sequencing batch reactor by a consortium of isolated halophilic microorganisms

• Main Authors: Pendashteh, Alireza, Ahmadun, Fakhru'l-Razi, Chuah, Teong Guan, Awang Biak, Dayang Radiah, Madaeni, Sayed Siavash, Zainal Abidin, Zurina
• Format: Article
• Language: English
• Published: Taylor & Francis 2010
• Online Access: http://psasir.upm.edu.my/id/eprint/37830/1/Biological%20treatment%20of%20produced%20water%20in%20a%20sequencing%20batch%20reactor%20by%20a%20consortium%20of%20isolated%20halophilic%20microorganisms.pdf; http://psasir.upm.edu.my/id/eprint/37830/; http://www.tandfonline.com/doi/abs/10.1080/09593331003646612

Produced water or oilfield wastewater is the largest volume of a waste stream associated with oil and gas production. The aim of this study was to investigate the biological pretreatment of synthetic and real produced water in a sequencing batch reactor (SBR) to remove hydrocarbon compounds. The SBR was inoculated with isolated tropical halophilic microorganisms capable of degrading crude oil. A total sequence of 24 h (60 min filling phase; 21 h aeration; 60 min settling and 60 min decant phase) was employed and studied. Synthetic produced water was treated with various organic loading rates (OLR) (0.9 kg COD m−3 d−1, 1.8 kg COD m−3 d−1 and 3.6 kg COD m−3 d−1) and different total dissolved solids (TDS) concentration (35,000 mg L−1, 100,000 mg L−1, 150,000 mg L−1, 200,000 mg L−1 and 250,000 mg L−1). It was found that with an OLR of 0.9 kg COD m−3 d−1 and 1.8 kg COD m−3 d−1, average oil and grease (O&G) concentrations in the effluent were 7 mg L−1 and 12 mg L−1, respectively. At TDS concentration of 35,000 mg L−1 and at an OLR of 1.8 kg COD m−3d−1, COD and O&G removal efficiencies were more than 90%. However, with increase in salt content to 250,000 mg L−1, COD and O&G removal efficiencies decreased to 74% and 63%, respectively. The results of biological treatment of real produced water showed that the removal rates of the main pollutants of wastewater, such as COD, TOC and O&G, were above 81%, 83 %, and 85%, respectively.