Establishment of water environmental purification system basing on resource cycle with forage rice

点击翻译按钮获取中文摘要

In the laboratory experiment, the nitrogen removal efficiencies and the biomass production were compared between surface flow (SF) and vertical flow (VF) system. It is found that the nitrogen removal efficiencies in the VF systems were higher than those in SF systems both irrigated by synthetic river water and livestock wastewater. In addition, the nitrogen efficiencies planted with forage rice were higher than those without plant. The above-ground biomass of forage rice under the condition of VF irrigated by livestock wastewater was the highest, achieved 3.0 kg dry weight m^<-2>. The nitrogen contents assimilated by above-ground biomass were about 80% of the entirely nitrogen content under VF systems and 90% under SF system.On the other hand, compared with the concentrations of Estrone(E1) (10μg/L) and 17β-Estradiol(E2) (6.4μg/L) in the influent, those in the effluent were lower than 2.0μg/L, suggesting that 80% and 69% of these two kinds of Endocrine-disrupting compound were removed by VF systems with forage rice.We investigated nitrogen removal performance and behavior in the field planted with forage rice and irrigated by nutrient polluted river water. The average nitrogen removal rate was 175 mg m^<-2> d^<-1>. Most of the nitrogen taken up by rice plants was contained in the aboveground biomass, with the mean amount being 34 g N m^<-2>. Since forage rice containing nitrogen could be supplied to livestock industry through Whole-Crop Silage, The results indicate wetland system using forage rice are useful in reduction of nitrogen loading to the environment as well as increase of feed self-sufficiency rate in Japan.