To enhance eutrophic water improvement effect, three parallel lab-scale oxidation pond-vertical subsurface flow constructed wetland-stable pond combined systems with different microporous intermittent aeration positions were constructed. The purification effect of each system was determined, and the contribution rate of each part of the system was also calculated. The characters of bacterial community under different aeration positions were also analyzed. Microporous intermittent aeration rate of 5 mg/L was chosen as the aeration rate for follow-up experiment. The result showed that the best CODCr, total nitrogen, and total phosphorus removal efficiencies were achieved by the combined system with bottom microporous intermittent aeration, and the efficiencies were 71.04%, 79.52%, and 95.10%, respectively. The best ammonium nitrogen removal efficiency was 92.62% and was achieved by the combined system with surface microporous intermittent aeration. After analyses, 14 strains of bacteria associated with the removal of N elements were found and 8 strains of bacteria associated with P element cycle were found.
Keywords: Bacterial community; Constructed wetland; Microporous intermittent aeration; Nutrition removal.