Effect of the combination of wetland and sewage treatment technology on the treatment of domestic sewage in Zhejiang province

Sample from 25 A(2)O + horizontal flow constructed wetland (HFCWs) and 49 A(2)O + vertical flow constructed wetland (VFCWs) in Suzhou, Huzhou, and tested inflow and outflow (COD, NH3-N, TN, TP and SS), to evaluate the stability of the effluent and the rate of compliance. The effects of the two combined processes on the treatment of rural domestic sewage and their design and operation were compared and studied. The results show that the stable effluent compliance rate of A(2)O + VFCWs is higher than that of A(2)O + HFCWs. The effluent quality stability of A(2)O + VFCWs is better in winter, but worse in summer. The removal effect of the A(2)O unit in the two combined processes is not ideal, which may be related to the low carbon to nitrogen ratio of the influent and less sludge. Based on the above results, it is recommended that the county-level city proceed with upgrading and reconstruction in terms of structure and operation.