Kinetic Modelling of the Removal of Seven Common Pollutants in Subsurface Flow Constructed Wetlands

The main removal mechanisms for the degradations of seven pollutants in wastewater treatment wetlands were analysed,and a mathematical model was established to quantify the removal of each pollutant,based on its main removal mechanisms.Subsurface horizontal flow wetlands were treated as a series of continuous stirred-tank reactors(CSTRs).Kinetic models for the removal of biochemical oxygen demand,chemical oxygen demand,ammonia,total nitrogen and faecal coliforms were established by combining Monod or first-order kinetics with CSTR assumptions.These tentative models account for a wide range of factors that affect wetland performance,but the models have not been proven by experiment data.Depending on the derivation of various coefficients in the models and verification by actual performance data,this study may provide a starting point for an integrated pollutant removal model to be developed,and experimentally verified,thereby making a step forward from the current greenbox'approach of wetland design.