Nitrate Removal from Water and Wastewater by Myriophyllum spicatum and Ruppia maritima

There are several methods for nitrate removal that are often very costly. The use of aquatic plants due to its low cost and environmental compatibility has attracted the attention of researchers for many years. To use two species of Myriophyllum spicatum and Ruppia maritima in nitrate removal, an experiment was conducted in three treatments and three replications with closed flow. After 2 months of in vitro test, a 30-day retention time was considered for the study. The results showed that there was a significant difference in nitrate uptake in all treatments except period 6. After 30 days, the uptake index of Myriophyllum spicatum was 87.13 and Ruppia maritima was 92.53. Dry weight of Ruppia maritima was significantly increased at the end of experiment, while it was not significant for Myriophyllum spicatum. The significant difference between the mean nitrate in the samples and the control sample during different time indicates the existence of a factor other than bacterial decomposition, which is the presence of plants in this study. Based on the results, these macrophytes are a suitable option to reduce the load of nitrates and organic matter in contaminated water. It should be noted that the need to improve water quality and maintain the quality level is to control these macrophytes to prevent the return of nutrients in their tissue to the environment during the decomposition process.