Comparison of ethanol, methanol and succinate effects as carbon sources on effluent biological denitrification

Abstract

Abstract Background: Increase of nitrate concentration in water sources is becoming a serious problem in many parts of the world. Nitrogen containing compounds released into environment can create serious problems, such as eutrophication of water sources and hazard potential to human health, because it has potency of causing methemoglubinemia disease and cancer. Between recommended methods, biological denitrification is an effective method to remove nitrate from water and wastewater. Materials and methods: In this study, biological nitrogen removal process was evaluated using ethanol, methanol and succinate as different organic carbon sources in batch scale. The different parameters, carbon source, initial nitrate concentration, pH, and inoculated of bacteria were evaluated. Results: The experimental results were showed that bacteria can not use methanol as carbon source. The dinitrifyers bacteria can dissimilate 200 mg/L No3-N, in the optimum condition: 28 ºC, pH 7.2 and initial inoculation of 3×108 CFU/ml, respectively. In the process, produced nitrate-N was less than 1 mg/l. Conclusion: The bacterium Pseudomonas stutzeri can use ethanol as carbon source for biological denitrification, but efficiency of succinate was better than ethanol.