Deep row trenching of waste water treatment works sludge: modelling water flow and nutrient transport in soil profile with HYDRUS-2D

Abstract

HYDRUS-2D was used in simulating water flow and nutrient (nitrate and phosphorus) transport through soil profile from entrenched waste water treatment works sludge under four different application treatments. The objective was to simulate nutrient migration processes with conceptual simplifications of the inputs to the model based on field evidence, soil survey data and applicable literature. Hydrological modelling of the system require the relationship between the soil moisture content (θ), soil water potential (h) and saturated hydraulic conductivity (Ks). Model application indicated that, the simulated water flow in soil profiles over the monitoring period compared favorably to measured observed soil water contents. However, simulated nutrients transport indicated generally poor direct correlations with measurements but responses of the simulation and observations are similar and the similarities are true for the range of depths simulated in each profile