Simulating the fate and transport of coal seam gas chemicals in variably-saturated soils using HYDRUS

摘要: The HYDRUS-1D and HYDRUS (2D/3D) computer software packages are widely used finite element models for simulating the one-, two- or three-dimensional movement of water, heat, multiple solutes in variably-saturated media, respectively. While standard consider only fate transport individual subject to first-order degradation reactions, several specialized add-on modules can simulate far more complex biogeochemical processes. objective this paper is provide a brief overview their modules, demonstrate possible applications subsurface chemicals involved coal seam gas extraction water management operations. One application uses model evaluate natural soil attenuation potential hydraulic fracturing transformation products case an accidental release. By coupling processes retardation, convective-dispersive biocide bronopol its products, we demonstrated how reduces initial concentrations by than factor hundred top 5 cm soil. A second UnsatChem module explore use produced sustainable irrigation. Simulations with different irrigation waters (untreated, amended surface reverse osmosis treated) provided detailed results regarding chemical indicators plant health, notably SAR, EC sodium concentrations. third HP1 analyze trace metal involving cation exchange complexation sorption reactions leached following some release scenario. Results show that main process responsible migration naturally present metals inorganic ligands such as (bi)carbonate enter upon infiltration alkaline water. examples were selected users tailor required complexity specific needs, rapid screening risk assessments various nder generic conditions, site-specific analyses actual pollution problems.