Native Bacterial Mixed Culture: A Proportionate Solution for Reinery and Petrochemical Wastewaters Mohammad Mahdi Zamani 1, 2 , Seyedeh Hamideh Mortazavi 1 , Marzieh Aligholi 3 , Hodiseh Mahmoud Janlou 3 , Samira Khodi Aghmiuni 3 , Malihe Sadat Pormasjedi-Meibod 4 , Nagh- meh Ghanadian 3 , Mehrdad Azin 4 , Mahmoud Ghazi Khansari 2, * 1 Students' Scientiic Research Center, Tehran University of Medical Sciences, Tehran, IR Iran 2 Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, IR Iran 3 Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, IR Iran 4 Department of Biotechnology, Institute of Advanced Technology (IAT), Iranian Research Organization for Science and Technology (IROST), Tehran, IR Iran * Corresponding author: Mahmoud Ghazi Khansari, Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Poorsina Ave, Ghods St, Enghelab St, P. O. BOX: 13145 - 784, Tehran, IR Iran. Tel.: +98-2166402569, Fax: +98-2166402569, E-mail: hin@sina.tums.ac.ir; ghazikha@sina.tums.ac.ir ABSTRACT Background: Heat, chemical and organic pollution are three types of environmental pollution, caused by reinery and petrochemical industries. Problems caused by hear and chemical pollutants are currently resolved to some extent but organic pollution such as Poly Aromatic Hydrocarbons (PAHs) are still considered as important problems of industry and environment. Objectives: A laboratory study was carried out to investigate the efects of native bacterial mixed culture (BMC) isolated from mixtures of reinery and petrochemical wastewaters for treatment of wastewaters of reinery and petrochemical industries. Materials and Methods: All bacteria were isolated from two reineries and two petrochemical plants of Iran. Several bacterial strains from both kinds of wastewater were mixed and two inal stock culture collections (BMC a and BMC b ), showed the ability to improve the growth among strains. BMC a was added to the reinery wastewater (activated sludge inluent sample) and BMC b was added to petrochemical wastewater (activated sludge inluent sample). The efects of continuous and non-continuous aeration at high and low pressures, along with the efects of nutrient addition in the beginning of experiment versus sequential addition at speciic time intervals, were studied. Results: Native BMC, when continuous high level aeration was used, decreased chemical oxygen demand (COD) in reinery and petrochemical wastewaters for about 81% and 63%, respectively. Gradual addition of nutrients increased COD removal of reinery and petrochemical wastewaters to 85% and 87%, respectively. Conclusions: Native BMCs from mixture of reineries and petrochemical wastewaters can be an efective method of wastewater treatment of both regional reinery and petrochemical plants. High pressure continuous aeration and gradual nutrient addition to the native BMCs can improve bioremediation of organic wastewater in diferent industries. Keywords: Agricultural Inoculants; Environment; Petroleum; Waste Management Copyright © 2012, Tehran Students’ Research Centers Network; Published by Kowsar Corp. Article type: Research Article; Received: 26 Jul 2012, Revised: 12 Sep 2012, Accepted: 08 Nov 2012; DOI: DOI: 10.5812/thrita.7278 Implication for health policy/practice/research/medical education: Native Bacterial Mixed Cultures from mixture of reineries and petrochemical wastewaters can be used for wastewater treatment of both regional reinery and petrochemical plants as an efective and inexpensive method to reduce environmental oil industries induced contamination. Please cite this paper as: Zamani MM, Mortazavi SH, Aligholi M, Mahmoud Janlou H, Khodi Aghmiuni S, Pormasjedi-Meibod MS, et al. Native Bacterial Mixed Culture: A Proportionate Solution for Reinery and Petrochemical Wastewaters.Thrita J Med Sci.2012;1(4): 149-54. DOI: 10.5812/thri- ta.7278 Copyright © 2012, Tehran Students’ Research Centers Network; Published by Kowsar Corp. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which per- mits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.