Study of nitrogen removal by aquatic plants duck weed and elodea from municipal Effluent in experimental pilots

Due to present of nitrogen as nutrient element in municipal effluent, discharging of it to water resources leads to increasing growth of different types of algae consequently eutrophication. So it is necessary to decrease the amount of nitrogen as much as possible before discharging effluent to water resources. The use of plants is one of the effective methods for refining polluted water. An experiment was carried out with on two plants elodea (egria densa), duck weed (lemna minor) with 4 treatments and three replicates in a completely randomized factorial design in experimental pilots with the batch. Treatments included effluent with the plant, effluent diluted with the plant and no plant (control) in two levels (initial and diluted effluents). Parameters of nitrate, ammonium, organic nitrogen and total nitrogen were measured in trend time of 8, 16 and 24 days in effluent samples and total nitrogen of plant tissue at the beginning and end of experiment period. The results showed that the concentration of nitrate, ammonium, organic nitrogen and total nitrogen in plant treatments were significantly lower than treatments without plants significantly, so that Elodea treatment reduced the concentration of nitrate, organic nitrogen and total nitrogen, as 31.56, 10 and 10.7%, respectively. The highest total N uptake was found in duck weed plant. It is concluded that duck weed is more effective in the removal of nitrogen than the elodea plant.