Removal efficiency of nitrate, phosphate, fecal and totalcoliforms by horizontal subsurface flow-constructed wetlandfrom domestic wastewater

Background: Constructed wetlands are systems designed based on the utilization of natural processes, including vegetation, soil, and their associated microbial assemblage to assist in treating different types of wastewater. Methods: Two local Appalachian plants (Louis latifolia and Phragmites australis) were planted into smallscale constructed wetlands to treat domestic wastewater in the North of Iran. The influent wastewater and the effluent from each wetland were sampled daily for 120 days. Experiments were conducted based on the mean ± standard deviation (SD) by analysis of variance (ANOVA). Results: It was found that nitrate, phosphate, fecal and total coliforms were reduced by 84.4%, 94.4%, 96.3%, 93.9% for P. australis and 73.3%, 64.0%, 94.4%, 92.1% for L. latifolia, respectively. Conclusion: According to the results, by using the HF-CW technology with L. latifolia and P. australis plants, the treated wastewater fully meets the wastewater discharge parameters of WHO standards. Keywords: Nitrate, Phosphate, Wetland, Wastewater treatment, Iran