Numerical simulation for designing the nitrate removal by soil infiltration

A multicomponent solute transport model that includes the biochemical redox reactions and cation exchange reactions was developed. It takes into consideration four different phases: pore water phase, bio phase, soil matrix phase, and solid phase. The microbially mediated sequence of reactions was modeled using Monod type equations. The model computes changes in concentration over time caused by the processes of advection, dispersion, biochemical reactions, and cation exchange reactions. A soil column experiment was conducted to determine the behavior of chemical species in aoil columns applied with secondary treated sewage water. The soil column experiment and the solute transport model had produced interesting observations on the behavior of different chemical species. The observed concentrations correlated fairly well with the simulated concentrations. The model reproduced the sequential reduction reaction. O₂ was reduced first after 30 hours then followed by NO₃^- after 31 hours. In this study, the numerical simulation of NO₃^- was done using the multicomponent solute transport model to determine the effect of pore velocity and input C H₂O concentration needed to reduce the NO₃^- leaching. It is revealed that the multicomponent solute transport model is useful to design the land, treatment system for NO₃^- removal from wastewater.