Studying the Effluent Quality of Enhanced Modified Ludzack Ettinger-oxic Settling Anaerobic Process (E-MLE-OSA) for Treating Real Municipal Wastewater

Background: Wastewater collection, treatment, discharge, additionally as reusing the treated wastewater in urban are critical factors for maintaining public health preventing contamination of water resources. This study aimed to investigate the performance of enhanced modified Ludzack Ettinger process-oxic settling anaerobic (MLE-OSA) process for treating real municipal wastewater in Sari wastewater Treatment, Sari City, Iran.Methods: To combine the OSA process technique with the MLE system, the Sludge Holding Tanks (SHT) were implemented in the return sludge line of designed pilot studies which comprised ۱) MLE, which was regarded as the control system similar; ۲) MLE-OSA۴ with a ۷۰-L SHT operated at ۴-h Hydraulic Retention Time (HRT), and ۳) MLEOSA۶ with a ۱۰۷-L SHT operated at ۶-h HRT. To start the process, the overflow effluent of the primary settling tank of the Sari wastewater treatment plant was used. After ۴۵-۶۰ days, the reactors reached a steady state. The parameters of Dissolved Oxygen (DO), Oxidation-Reduction Potential (ORP), temperature, pH, Chemical Oxygen Demand (COD), Biochemical Oxygen Demand (BOD۵), Total Suspended Solids (TSS), and nutrients were analyzed.Results: The results revealed that the average TSS, COD, BOD, phosphorus, nitrite, nitrate, and total nitrogen in MLEOSA۴ effluent decreased ۲۰.۱, ۱۴.۶, ۲.۹۷, ۱۰, ۵۱.۱, ۱۹.۳, and ۲۰.۷%, respectively compared to MLE. Similarly, in MLE-OSA۶, the values decreased ۳۴.۲, ۱۶.۱, ۱۴.۶, ۱۶.۷, ۶۹.۶, ۳۱.۳, and ۲۵.۸%, respectively compared to the control process.Conclusion: Therefore, using natural wastewater, the enhanced MLE-OSA process showed better performance in removing the study parameters and better quality for the effluent. Furthermore, the quality of effluent is following the Iran Department of Environment (IDE).

کلیدواژه ها:

Municipal wastewater ، Wastewater Treatment ، MLE process ، OSA process ، nutrient removal ، Enhanced MLE-OSA process