Application Study On Cyperus Alternifolius Foam Board Float Island In Linjiang River

Artificial floating island(AFI) is a new water process method.polluted materials in water are absorbed and transformed by plants and microbe in the AFI,pollued water is purified in river.This study get main conclusions through intermediate test of AFI in the Linjiang river.Height,root and biomass of Cyperus alternifolius are bigger than Vetiveria zizanioiaes in same growth period,In the filtration test of AFI plant.Removal loading of Cyperus alternifoliu and Vetiveria zizanioiaes to TN,TP and COD are respectively 1.83 g/(m~2.d),0.23 g/(m~2.d),3.28 g/(m~2.d) and 1.44 g/(m~2.d),0.19 g/(m~2.d),2.98 g/(m~2.d).Comparing growth condition and purifying effect of two plants, Cyperus alternifolius is more suited as plant of AFI.Operational parameter test of Cyperus alternifolius AFI shows purifying effect is good when HRT adopt 3 days, coverage rate adopt 30% and hydraulic loading adopt 0.30m3/(m~2.d). In using the above operational parameter the condition,and inflow concentration of TN,TP,COD,and DO are respectively 31.00mg/l, 2.60 mg/l,32 mg/l and 1.2 mg/l,removal loading of TN,TP and COD are respectively 3.72 g(/m~2.d),0.32 g(/m~2.d)and 3.6 g/(m~2.d),and DO concentration is 1.0 mg/l.Content of nitrogen and phosphorus is 14.57mg/g and 4.43mg/g in the Cyperus alternifolius body,and accumulation of nitrogen and phosphorus above water surface is bigger than by far below water surface.Contribution of plant absorbtion is 5.86% and 14.21% to nitrogen and phosphorus removal,it is a little in gross.Removal loading of TN decline 36% after plant was harvested,and removal loading of TP and COD decline 22% and 21%.Plant harvest is unable ruinous influence to process effect of the system.The results showed Cyperus alternifolius artificial floating island could effectively remove nitrogen and phosphorus and COD in polluted river,and function was steady. It's a effective measure which control pollution in the branch of the three gorges reservoir.