A survey on detergent removal in Tabriz wastewater treatment plant based on activated sludge method

Surfactants are organic chemicals that aggregate in joint surface of gas-liquid or solid liquid phases so as to change the water physical properties to accelerate the deterging process by decreasing surface tension. Surfactants, in fact, are the main chemicals in detergents and constitute 5-30% of the detergents by weight. Detergents enter the environment, through the direct discharge of raw wastewater or treated effluent, and reduce the quality of water resources and increase treatment costs. The detergents discharge limits, based on effluent discharge standards are as 1.5 mg/l for surface water, 0.5 mg/l for groundwater and agricultural use. The goal of this study was to investigate the efficiency control of Tabriz wastewater treatment plant. In this experimental research the detergent amounts of raw and treated wastewater were measured for six successive weeks; six samples per week. Anionic surfactants were determined through MBAS method and compared with discharge standards. The findings showed that detergent amounts in raw wastewater was about 1.23 to 5.23 mg/l and in treated waste water 0.093 to 0.263 mg/l. The removal efficiency was determined to be 93%.Considering the results of this research and comparison of high removal efficiency of detergent discharged into environment, it was observed that the amount of chemical and environmental factors of effluent were lower than that of standard values into surface water and groundwater. So this can be found an efficient alternative method for treatment of urban wastewaters.