Evaluation of the Performance of Advanced Sequencing Batch Reactor Biological Processes in the Removal of Nutrients from Municipal Wastewater in Yazd City: A Case Study

Advanced Sequencing batch reactors (SBR) are one of the most suitable modified activated sludge systems. Due to low cost, optimal efficiency, and easy operation, they are recognized as an effective biological treatment system. The purpose of this study was to determine the performance of the SBR biological process in the removal of organic matter and nutrients from Yazd city wastewater.

This descriptive study examines the trend of organic matter and nutrients changes in the biological process of advanced SBR. In this study, the samples were taken from the input and output of the SBR process four times a month for 9 months in 2019. A total of 72 samples were taken. Then COD (chemical oxygen demand) and BOD5 (biochemical oxygen demand) and nutrients (phosphate ( ), total phosphorus, ammonium ( ), nitrate ( ), and nitrite  were measured. Finally, the results were analyzed by one-sample t-test at a significance level of 0.05.

The concentration of COD and BOD5 in the effluent was 42 and 14 mg/L, respectively. The concentration of total phosphorus, phosphate, ammonium, nitrate, and nitrite in the effluent was also shown to be 2.9, 2.4, 6.3, 9.01, and 0.92 mg/L, respectively.

The results showed that the active sludge system in the Yazd wastewater treatment plant has a good and acceptable situation. This has caused a significant reduction in organic matter and nutrients. These results are in accordance with the standards of the Iranian Environment Organization in the reuse of wastewater.