Study on the bioremediation potential of Najas indica

The aim of this paper is to investigate the bioremediation potential of Najas indica. In the present study, the removal rates of N. indica on nitrogen and phosphorus were analyzed at 4 planting densities(1, 2, 3 and 4 g/L) and 3 eutrophic water degrees(mesotrophic, eutrophic and utmost eutrophic), which detected the concentration of NH₄-N, NO₃-N, TN and TP. Besides, the inhibitory effect of N. indica on the growth of M. aeruginosa was studied by the analysis of the number of M. aeruginosa and the concentration of nutrients. The results showed that removal rates of N. indica on nitrogen and phosphorus were significantly high. At the planting density of 4 g/L, the removal rates of TN and TP were up to 99.50% and 93.45%, respectively, while there is no significant difference between different treatments. Eutrophic degrees have a significant effect on the removal rates of nitrogen and phosphorus. The uptake rates of N. indica on nitrogen and phosphorus were increasing as the nutrient increased, and the uptake rates of TN and TP reached the highest 1.11 and 0.15μmol/(g·h), respectively. In the utmost eutrophic group, the removal rates of TN and TP also reached the highest 99.46% and 90.75%, respectively, which were significant higher than other eutrophic levels. Meanwhile, N. indica had an obviously inhibitory effect on the growth of M. aeruginosa, and algal inhibiting rate reached 99.89% in the experimental group. The detection results of water quality showed that the concentration of TP and NH₄ under co-culture condition was lower than control group significantly. Based on the study, N. indica presents a potential application for remediation of the eutrophic water ecosystem and prevention of the bloom caused by M. aeruginosa.