Nitrogen and phosphorus removal from contaminated water by five aquatic plants

Five aquatic macrophytes, Acorus calamus, Lythrum salicaria, Monochoria korsakowii Alisma orientale and Sagittaria sagittifolia were tested for the relative growth rate (RGR) and abilities of removing total nitrogen(TN) and total phosphorus (TP) by the manipulative indoor experiment. Result revealed that the RGR of M. korsakowii was the highest(0.818) among the five macrophytes, while that of A. orientale was the lowest (0.172). Also the abilities of different macrophyte species to remove nitrogen and phosphorous contrast sharply with one another. The results showed that A. calamus, L. salicaria, M. korsakowii and A. orientale had stronger ability to remove TN, the removal rates were 97.7%, 94.9%, 96.4%, 91.2% respectively. A. calamus and L. salicaria had stronger ability to remove TP, the removal rates were 96.1% and 83.4%. The order of TN purification capacities was: A. calamus > M. korsakowii > L. salicaria > A. plantago-aquatic> S. sagittifolia. But for TP, the order was A. calamus > L. salicaria > M. korsakowii > A. orientale> S. sagittifolia.