4. Conclusions
The findings of this study have shown that the sequential AS/VSFCW system was efficient in the removal of COD and N removal. The NO3-N removal efficiencies were obtained as 97% at nitrate loading rates of 245 mg/m2 d in VSFCF while the mean percentage of TN removal was 46.6% (n = 8, σ = 9.5) in the AS/VSFCW system. Based on experimental results of this and other studies nutrient (N, P) removal is possible and these systems are very cost effective compared to classic nutrient removal system. Constructed wetlands have been implemented as wastewater treatment facilities in many parts of the world, but to date, the technology has been largely ignored in developing countries where effective, low cost wastewater treatment strategies are critically needed. Conventional wastewater treatment plant could not remove N and P in sewage in order to prevent eutrophication in receiving water bodies. CWs may be an economical option for N and P removal in the effluent of secondary treatment such as activated sludge, trickling filter of oxidation ponds because conventional nutrient removal is much costly and complex compared to natural treatment systems such as CW and oxidation ponds.