Three lab-scale vertical-flow constructed wetlands （VFCWs）, including the non-aerated （NA）, intermittently aerated （IA） and continuously aerated （CA） ones, were operated at different hydraulic loading rates （...Three lab-scale vertical-flow constructed wetlands （VFCWs）, including the non-aerated （NA）, intermittently aerated （IA） and continuously aerated （CA） ones, were operated at different hydraulic loading rates （HLRs） to evaluate the effect of artificial aeration on the treatment efficiency of heavily polluted river water. Results indicated that artificial aeration increased the dissolved oxygen （DO） concentrations in IA and CA, which significantly favored the removal of organic matter and NH4＋-N. The DO grads caused by intermittent aeration formed aerobic and anoxic regions in IA and thus promoted the removal of total nitrogen （TN）. Although the removal efficiencies of CODEr, NH4＋-N and TN in the three VFCWs all decreased with an increase in HLR, artificial aeration enhanced the reactor resistance to the fluctuation of pollutant loadings. The maximal removal efficiencies of CODEr, NH4＋-N and total phosphorus （TP） （i.e., 81%, 87% and 37%, respectively） were observed in CA at 19 cm/day HLR, while the maximal TN removal （i.e., 57%） was achieved in IA. Although the improvement of artificial aeration on TP removal was limited, this study has demonstrated the feasibility of applying artificial aeration to VFCWs treating polluted river water, particularly at a high HLR.展开更多
基金support from the Ministry of Environmental Protection (No.2008ZX07101-006-08)the Ministry of Science and Technology of China (No. 2009BAC57B02)
文摘Three lab-scale vertical-flow constructed wetlands （VFCWs）, including the non-aerated （NA）, intermittently aerated （IA） and continuously aerated （CA） ones, were operated at different hydraulic loading rates （HLRs） to evaluate the effect of artificial aeration on the treatment efficiency of heavily polluted river water. Results indicated that artificial aeration increased the dissolved oxygen （DO） concentrations in IA and CA, which significantly favored the removal of organic matter and NH4＋-N. The DO grads caused by intermittent aeration formed aerobic and anoxic regions in IA and thus promoted the removal of total nitrogen （TN）. Although the removal efficiencies of CODEr, NH4＋-N and TN in the three VFCWs all decreased with an increase in HLR, artificial aeration enhanced the reactor resistance to the fluctuation of pollutant loadings. The maximal removal efficiencies of CODEr, NH4＋-N and total phosphorus （TP） （i.e., 81%, 87% and 37%, respectively） were observed in CA at 19 cm/day HLR, while the maximal TN removal （i.e., 57%） was achieved in IA. Although the improvement of artificial aeration on TP removal was limited, this study has demonstrated the feasibility of applying artificial aeration to VFCWs treating polluted river water, particularly at a high HLR.
