ABSTRACT
Set up stage represents the interval from system start of operation till the stability in media porosity and completion of the attached biofilm and plant growth. Through this stage Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand, and Total Suspended Solids were the main pollutants. Two main aspects are provided, the first one is the effect of wetland cell length and the second aspect is the effect of plant and attached biofilm growth on treatment efficiency. The effluent BOD concentration with distance, hydraulic loading rate, and influent concentration is studied. The variation of BOD removal efficiency with distance, hydraulic retention time, and time from the start of sampling is also determined. Concentration of BOD, which is gradually reduced with distance for the three media: rubber, gravel, and plastic may be represented by an exponential function that gives the best determination coefficient.
