MATHEMATICAL MODELING AND NUMERICAL SIMULATION OF PHOSPHORUS REACTIVE TRANSPORT IN AN HORIZONTAL SUBSURFACE FLOW CONSTRUCTED WETLAND TREATING GREYWATER.

The research work presented herein makes a contribution to HSSF CW grey-water treatment by developing a conceptual and numerical model to simulate the spatial and temporal variations of Phosphorus concentration. This paper presents the simulation of flow and phosphorus removal processes by using the advection-dispersion-reaction modeling approach. The flow equation is solved by using the mixed finite element method. The system of advection-dispersion-reaction is solved by using the technique of separation of the operators. The equation of advection is approximed by the Characteristics-Galerkin Method. The dispersion-reaction equation was carried by using the finite element method. The softwares freefem++ and matlab were used. This phenomenon was materialized by a horizontal subsurface Flow Constructed Wetland treating greywater in a Moroccan primary school. The decay coefficient has been identified by solving an inverse problem using observed data. Numerical simulation was validated after calibration on the basis of obtained experimental data by controlling water quality parameters over a period of 100 days. Comparative analysis shows that the total predicted effluent of phosphorus concentration obtained by the numerical simulation agrees fully with the one obtained by experimental data. [ABSTRACT FROM AUTHOR]