Evaluation of the Efficiency of Sub-Surface Constructed Wetland Methods in Wastewater Treatment in Yazd City in 2011

Using natural methods such as constructed wetland is one of the methods for municipal wastewater treatment that has the capacity of reducing costs of treatment and improving environment. The purpose of this study is to determine the efficacy of sub-surface constructed wetland in wastewater treatment in Yazd. This is an experimental study aimed of to determine the efficacy of sub-surface constructed wetland for the removal of COD، BOD5، TSS، PO4-P، NH3-N، NO3-N، Total coli form and Fecal coli form Parameters. For this two reactors were constructed as pilot with retention time for 4 days. Within 2 months، samples were taken from the input and output reactors according to standard methods and were analyzed with the statistical software SPSS ver 11. 5 and Excel 2003. The results showed that the removal efficiency of COD، BOD5، TSS، PO4-P، NH3-N، NO3-N، Total coli form and Fecal coli form Parameters in Cyperus Alternifolius was 74، 73، 84، 40، 36، 33، 70 and 38% respectively، and in control wetland was 44، 34، 77، 15، 0. 3، 1، 17 and 26% respectively. According to the findings، sub-surface constructed wetland has high efficiency in removing organic matter and solids and can be used، in Iran، for agriculture and irrigation. Also this plant has a high efficiency in removing nutrients and total Coli forms and fecal Coli forms. However more studies can be done on the effectiveness of this method to remove nutrients، heavy metals، parasites، parasite eggs and Intestinal virus.