Evaluate the effectiveness of the phytoremediation method of removing phosphorus from agricultural drainage water (Case Study: Vetiver, Typha and Reed)

Phosphorus is the most effective nutrient in feed efficiency phenomenon in surface water resources. Soil erosion is the loss of phosphorus from agricultural land and discharge into the agricultural drains. Phytoremediation of 1980 as a practical and affordable solution used to remove pollutants. Phytoremediation selecting plants that absorb pollutants in addition to ability, to grow in polluted and have high transpiration is very important. There is a wide range of plants and trees in order to measure the efficiency of the process Phytoremediation around the world have been studied. This study aimed to evaluate the phytoremediation strategy to reduce phosphorus in agricultural drainage water, phosphorus uptake capacity by three plant Vetiveria zizanioides, Typha latifolia and Phragmites australis in a factorial in randomized complete design with three replications was studied in Guilan province. For this purpose, 18 boxes with soil was ready and after cultivation of plants, water containing superphosphate triple at a concentration of 8 mg/liter and potassium nitrate at two levels 10 and 20 mg/liter was used to simulate the drainage water quality. During the experiment, the ability to reduce phosphorus by plants at depth of 35 and 70 cm, extracts was determined by measuring orthophosphate. During the experiment, the ability to reduce phosphorus by plants at 35 and 70 cm was determined by measuring orthophosphate of soil extracts. The results showed that the maximum absorption of the orthophosphate was in reed at concentration 10 mg/liter and 35 cm with 99.8 percent and the least in depth of 35 cm and a concentration of 20 mg/liter of the Vetiver plant with 99.2 percent was occurred. Also reduction in soil's orthophosphate by Typha at concentration of 10 mg/liter and 70 cm was 99.9 percent. The results showed the effect of nitrate concentration on orthophosphate removal of effluent therefore nitrate concentration must be considered in design of phytoremediation system. Because Phragmites australis has lowers standard error (0.001) and mean orthophosphate (0.019 mg/l), was better than the two other plants in the uptake of orthophosphate. After Phragmites australis, Typha latifolia and Vetiveria zizanioides with mean values of orthophosphate 0.035 and 0.138 mg/l, respectively could absorb orthophosphate. Furthermore results showed the increasing in depth of soil in Vetiver and Phragmites australis plants leads to decrease in orthophosphate removal. According to the results, Phragmites australis is proposed to remove orthophosphate from agricultural waste water, especially in Phytoremediation of surface drainage system in Guilan province.