Efficiency of conventional activated sludge in the removal of linear alkylbenzene sulfonate from municipal sewage

Introduction: LASs are anionic detergents that produced widespread in different countries and discharged into natural environment through wastewater collection systems that have adverse impacts on environment. Wastewater treatment systems are responsible for removing these contaminants. The purpose of this study is to determine the efficiency of a conventional activated sludge system for removing linear alkyl benzene sulfonate from wastewater in Kermanshah. Material and method: This study is a cross sectional descriptive and conducted for 10 months. In order to determine the efficiency of the activated sludge process 60 wastewater samples were taken from influent, effluent of primary sedimentation and effluent of wastewater treatment system, then LAS concentration was measured. All the sampling and testing methods were performed according to standard method guidelines. Results: The results showed the average of LAS removal in winter and warm seasons were obtained 90.8% and 96.5%, respectively. The total removal of LAS in this system was 93.9 ±3.6. In addition COD and TSS removal in winter were measured 88.3% and 72.3%; these values in summer were 86.9%, and 83.3%, respectively. Conclusion: The results showed that the conventional activated sludge process is effective for removal of LAS concentration. In summer season the effluent concentration of LAS is less than environmental standards for discharge to surface water