[Effects of Wastewater Nitrogen Concentrations and NH/NO on Nitrogen Removal Ability and the Nitrogen Component of (Vell.) Verdc].

Solution culture experiments were conducted to investigate the effect of wastewater nitrogen levels and NH/NO on nitrogen removal ability and the nitrogen component of . Experiments with three nitrogen levels and NH/NO were set up as follows:20, 100, and 200 mg·Land NH/NO 1:0, 0.5:0.5, and 0:1. The results showed that the biomass of plants increased fastest during the first week. The plants treated with NH/NO=1:0 with nitrogen levels of 20 and 100 mg·L and those treated with NH/NO=0.5:0.5 with a nitrogen concentration of 200 mg·L exhibited higher biomass than the others. The removal rates of water total nitrogen, ammonium nitrogen, and nitrate nitrogen during the first week were the maximum for all treatments and increased with water nitrogen levels. There were no significant differences in the removal rate between ammonium nitrogen and nitrate nitrogen with a nitrogen level of 20 mg/L, while with nitrogen levels of 100 and 200 mg·L, the nitrate removal rates were higher than those for ammonium nitrogen. The nitrogen accumulation and its contribution rate to nitrogen removal from water and sediment were all increased with water nitrogen levels and increased fastest during the first week. The contribution rate of nitrogen accumulated by plants with NH/NO=0:1 was the highest with nitrogen levels of 20 mg·L, while plants with NH/NO=0.5:0.5 were the highest with nitrogen levels of 100 and 200 mg·L. The protein, amino, and nitrate nitrogen contents in plants were all increased by increasing water nitrogen levels with a ranking of protein content > amino nitrogen content > nitrate nitrogen content. The protein concentrations in plants with NH/NO=1:0 and NH/NO=0.5:0.5 were higher regardless of water nitrogen levels, while the amino nitrogen concentration in plants with NH/NO=1:0 and the nitrate nitrogen content in plants with NH/NO=0:1 were higher than the others. It was concluded that the nitrogen removal ability of was improved by raising water nitrogen levels under the tested condition, which indicates that could purify high nitrogen wastewater. is an ammonium-nitrophile, but had the strongest capacity for growing and removing wastewater nitrogen exhibited with higher than 100 mg·L nitrogen levels only with equal NH to NO. The nitrogen component concentrations of protein, amino, and nitrate in plant were all affected by the ratio of NH/NO.