Assessment of Anaerobic Baffled Reactor Upgrade by Integrated Electrocoagulation Process for Municipal Wastewater Treatment

Background & objectives: Anaerobic baffled reactor (ABR) is one of the low cost wastewater treatment systems compared to the aerobic method. Hoverer it should be studied and developed to overcome its limitations such as insufficient nutrient removal. The aim of this study was to evaluate the efficiency of the 5 sectional ABR pilot and improve it with integrated electric coagulation process for municipal wastewater treatment. Methods: This study was conducted at Khoy wastewater treatment plant. The ABR was operated for 270 days with hydraulic retention time (HRT) 36-24-18-12h and the integrated reactor was operated for 40 days with duration of 18 hours. The reactors were fed in line from the incoming wastewater to the treatment plant. From the input and output of the system, 245-hour combined sampling was performed 225 times and the parameters COD, BOD, TSS, TKN, and TP were measured. Results: The reactor startup took about 105 days. The ABR reached to 79 - 91%, 9-20%, 19-30% and 89-94% COD, TKN, PO4 and TSS removal efficiencies respectively at HRT36 and 12 h. The ABR meted effluent disposal standards of TSS in all conditions and those of COD, TP and BOD at optimum HRT 36h. The integrated ABR meted these and NO3, SO4 standards at HRT 18 h in current density of 0.1mA/cm2 by aluminum electrodes. Conclusion: The ABR is suitable for municipal wastewater treatment, but it has limitations such as high HRT and failure to meet nitrogen effluent discharge standard. By integrating the EP into the ABR while reducing HRT, its efficiency increased up to twice that of ABR with the same time. Therefore, integrated electrical coagulation can be used to improve ABR efficiency.