Effects of main factors on remedying northern landscaping water by hybrid ecological filter

Natural zeolite and coal cinder were layered as main packing medium of the ecological filter instead of traditional filling to remedy the static lake water in Northern China. The ecological filter was running in a combined upward and downward flow mode. Dynamic experiments were carried out to study the effects of retention time and ambient temperature on pollutants' removal efficiency of the hybrid ecological filter. The function of plant was also studied by contrast test. It is showed that the removal efficiencies of NH₄⁺-N and TP are increased when the retention time is changed from 1 h to 2 h and 4 h, but the removal efficiency of TN is decreased, the removal efficiency of NH₄⁺-N is increased from 91.5% to 98% and that of TP is increased from 31.8% to 52.5%. When the temperature declines, the temporal removal efficiency of NH₄⁺-N is reduced, but the removal efficiency of 24 h and 48 h is remained. The removal efficiency of TP after 24 h and 48 h is decreased when the temperature declines evidently. The retention time plays an important role in NH₄⁺-N and TP removal, and the ambient temperature is significant for TP removal. The plant favors for TP and organic matter removal but has little effect on TN removal.