Synergism Of Novel VSF-CFCW And BAF For Sewage Treatment In Cold Climate

Synergism of the novel vertical subsurface flow carbon fiber constructed wetland (VSF-CFCW) and biological aerated filter (BAF) for a domestic sewage presented in this paper makes vertical subsurface flow carbon fiber constructed wetland, biological contact oxidation process and biological aerated filter organically combines intogether, which would make the clogged problem of subsurface constructed wetland be solved and meet demands of the SS concentration in the BAF influent.The first objective of the study was to test the contribution of artificial aeration, recirculation ratio without steel slag and recirculation ratio with steel slag on pollutant removal on condition that the HRT was kept unchanging and water quality remained stable in winter when the plants are dormant. In addition, the second objective of the study was to test the highest pollution load in different working conditions including artificial aeration, recirculation ratio without steel slag and recirculation ratio with steel slag when the various pollutants purification efficiency remained unchanged in winter when the plants are dormant. It has been shown that VSF-CFCW and BAF play different roles in removing contaminants from wastewater. During the airflow experiment, the removal efficiency of CODcr and TP in VSF-CFCW is higher than that in BAF, whereas BAF can compensate for the deficiency of VSF-CFCW where no significant improvement on ammonium nitrogen removal was observed. Yet, the removal efficiency of CODcr, TP and NH4+-N in VSF-CFCW can be improved apparently when different recirculation ratio or various mass concentration of steel are applied. Especially, the highest efficiency of 94.6%,77.9% and 80.7% for CODcr, TP and NH4+-N respectively, were achieved when the airflow of 0.06 L/h, the recirculation ratio rate of 60% and the mass concentration of steel of 2.2-2.4 g/L were applied. In addition, the mean purification efficiency of CODcr, TP and NH4+-N remained 91.93%,72.4% and 76.47% when the influent mean concentration of CODcr,TP and NH4+-N to come up with 1678.26 mg/L,25.63 mg/L and 212.03 mg/L under condition that optimum working conditions mentioned above.The presented results demonstrate that CODcr purification efficiency had improved apparently when artificial aeration was added in VSF-CFCW, that NH4+-N purification efficiency had raised obvirously when the integrated process adopted recirculation without steel, that TP purification efficiency had increased obvirously when the integrated process adopted recirculation with steel. The integrated treatment system of VSF-CFCW and BAF is proved to be an effective wastewater treatment technique and a better alternative to treat domestic sewage.