Performance of the combined SMBR–IVCW system for wastewater treatment

Abstract

A new SMBR–IVCW system, which combined a submerged MBR (SMBR) unit and an integrated vertical-flow constructed wetland (IVCW) unit, was applied to treat the high strength integrated wastewater. The study showed that this system of biological and ecological combination was stable and good at improving the quality and efficiency of polishing wastewater. Six runs under different HRT combinations were carried out in order to obtain the better purification performance of the SMBR–IVCW system. The results indicated that the better HRT combination was 7.7 h for SMBR and 11.52 h for IVCW. In such condition, the concentrations of COD, ammonia and TP in the final effluent were 11.0, 0.086 and 0.44 mg L − 1 , respectively, which reached the Class III of the national environmental quality standards for surface water in China. In fact, the HRT of the two units had great effect on the purification efficiency and investment cost. By regulating the ratio of HRT between these two units, the optimum operation conditions could be obtained to reach the double wins of high purification and low costs. In the SMBR–IVCW system, the SMBR unit acted as the secondary treatment, contributing to removing the organics and nitrification. While the IVCW unit was more like as the tertiary treatment, contributing to the denitrification and further dephosphorization.