Measuring the Pulse of SBR Technology: Efficiency, Contamination Indices, and Long-Term Trends.

This study assessed the long-term performance of sequencing batch reactor (SBR) technology for municipal wastewater treatment in Erbil, Kurdistan Region, Iraq, over the period 2021-2024. Four sampling stations (S1-S4) were monitored for key physicochemical parameters, including TSS, BOD₅, COD, turbidity, nitrate, and phosphate, before and after treatment. The reduction efficiency index (REI), contamination factor (CF), and pollution load index (PLI) were applied to evaluate system effectiveness and contamination trends. Results showed consistently high removal efficiencies (70%-90%) for TSS, BOD₅, COD, turbidity, nitrate, and phosphate. However, a gradual decline in performance was observed from 2022 to 2024, particularly for TSS, COD, and turbidity, indicating possible operational or load-related variations. Among all stations, S1 exhibited the most stable treatment efficiency, with PLI decreasing from 0.892 in 2021 to 0.517 in 2024, signifying improved water quality and sustained reactor performance. Overall, the findings confirm the reliability of SBR systems for municipal wastewater treatment under semiarid urban conditions, while emphasizing the need for continuous monitoring and operational optimization to maintain long-term efficiency.