Background: Linear alkyl benzene sulfonates (LAS) are the most important ionic detergents that produce negative ions in the environment. These compounds enter surface waters through domestic and industrial wastewaters and cause environmental hazards.
Objectives: The present study was aimed at assessing the performance of advanced sequencing batch reactor (SBR) in wastewater treatment plant of Yazd, Iran, to remove organic materials and detergents.
Materials and Methods: The present research was a descriptive longitudinal study conducted on 96 input and output samples of SBR system over eight months from October 2012 to June 2013. The studied parameters were biochemical oxygen demand 5 (BOD₅), chemical oxygen demand (COD), and detergents (LAS), which were assessed through standard methods. Finally, the study data were analyzed through analysis of variance (ANOVA) using software package for statistical analysis (SPSS).
Results: The mean inputs of BOD₅, COD, and LAS to the SBR system were 292.40 ± 45.28, 597.15 ± 97.30, and 3.29 ± 0.92 mg/L, and the mean outputs were 20.59 ± 3.54, 59.34 ± 9.47, and 0.606 ± 0.09 mg/L, respectively. The removal efficiency of BOD₅, COD and LAS were respectively 92.95%, 90.06% and 81.6%. The results of ANOVA indicated that there was a significant relationship between the mean inputs and outputs of BOD₅, COD, and the detergents (P ≤ 0.001).
Conclusions: With the proper operation of wastewater the treatment plant and increasing the retention time, the removal efficiency of the detergents increased. In addition, according to the environmental standards for BOD₅, COD and the detergents, the results of the present study indicated that the outputs of these parameters from the SBR system were appropriate for agricultural irrigation.