Area-based speciation kinetic analysis of multipollutant removal in constructed wetlands to enhance the treatment efficiency

Abstract

In the present study, area-based pollutant removal kinetic analysis was considered using the zero-order, first-order decay and efficiency loss (EL) models in the constructed wetlands (CWs) for municipal wastewater treatment. Except for SO₄²⁻ elimination, overall higher average pollutant removal performance was found in the CWs with gravel media only (P-CWs). The lowest value of 6.47 ± 4.72 of the efficiency loss co-efficient indicated the highest performance with a minimum discharge concentration of 0.54 ± 0.24 mg L⁻¹ of TN (84.70% removal) in the CWs integrated with iron scraps and granular activated carbon (ISs + GAC-CWs). The lowest level to 0.903 ± 0.89 of the model's predicted value (C_t-ISs) also confirmed the relatively higher average removal efficiency of 63.37% of nitrate with narrower discharge distribution in the ISs–GAC-CWs. The factors affecting pollutant removal in the CWs and trends of the reactions of the multipollutants were interpreted by using the kinetic modeling analysis. The results confirmed that VF-CWs, an ecotechnology, should be considered as an alternative to the conventional treatment methods of municipal wastewater for small communities, which is a sustainable solution.