Phosphate Removal from Karun Agro-Industry INC Agricultural Wastewater through Vetiver planation, and within Free Water Surface Constructed Wetland

To investigate the performance of artificially constructed wetland in phosphate removal from agricultural wastewater, free water surface constructed wetlands were employed. Nine rectangular pools were constructed and operated continuously from December 2013 until May 2014. Three of the units were filled with soil and planted with vetiver transplants (S), three were cultivated with vetiver on some floating platforms (F) and three kept non- planted as control (C). The study was divided into 6 phases, each of a 6 month, period, using three HRTs (3, 5 and 7 days). Concentration of phosphate was evaluated at the inlet vs outlet of the system, and the data analyzed, using SAS, to find out the significance between or among factors. The average phosphate concentration, in the wastewater entering the unit was recorded 5.99-8.58 mg/L. The results indicated that the phosphate removal performance of the constructed wetland units differed significantly (P