Effects of Different Shunt Rate on the Purification of Hybrid Constructed Wetland

A hybrid constructed wetland (HCW) system, comprised of a bottom-aerated vertical flow constructed wetland (VFCW) followed by a baffled horizontal flow constructed wetland (HFCW), was operated at different shunt rates (20%, 40%, 60%) to investigate the effect of shunt rate on the purification efficiencies of synthetic domestic wastewater in this study. The results showed that the optimal shunt rate was 40%, which had a greater removal rates of TN (75.5%), NH4+-N (61.7%), and COD (81.6%). High-throughput sequencing analysis revealed that the dominant phyla were Proteobacteria (49.8%), Firmicutes (14.4%), and Bacteroidetes (8.1%) in the HCW, and the richness and diversity of bacterial community in HFCW were higher than those of VFCW. Denitrifying bacteria was the dominant microorganism in the VFCW (21.4%) and HFCW (14.4%). Nitrification and denitrification were the main ways of TN removal in this study, in addition, the anammox was found in HFCW.