Efficiency of Straw Plants in Removal of Indicator Pathogens from Sub Surface Flow Constructed Wetlands of Municipal Wastewater in Yazd, Iran

Use of wetlands is one of the methods of natural municipal and industrial wastewater treatment. In addition to reducing the cost of treatment, this method has high efficiency in removing pollutants. The purpose of this study was to evaluate the efficiency of straw plants in Sub Surface Flow Constructed Wetland for removing Indicator Pathogens from Municipal Wastewater in Yazd, Iran. This is an applied-experimental study in which 100 samples were taken from four sub surface wetlands, which were covered by three straw plants including Bafgh, Yazdbaft and Ali Abad, and a control wetland. The samples were taken during the two seasons of winter and spring and were then transferred to the laboratory by ice. The experiments of total coliform, E. coli and fecal streptococcus were performed, according to the standard methods, on input and output samples of wetlands. The results of the current study showed that the average total removal of the four wetlands for total coliform, E. coli and fecal streptococcus were 80.43%, 74.11%, and 69.08%, respectively. Moreover, the removal efficiency in the Aliabad wetland for total coliform and E. coli were 98.22% and 99.27%, respectively; this was the highest removal rate among the wetlands. One of the main problems of the wastewater treatment method used in Yazd, which is stabilization ponds, is the low microbial removal. Thus, this problem can be solved by using sub surface wetlands with the Aliabad Straw species after the stabilization ponds.