Application of divided convective-dispersive transport model to simulate variability of conservative transport processes inside a planted horizontal subsurface flow constructed wetland

• Published in: Environmental science and pollution research international Vol. 28; no. 13; pp. 15966 - 15994
• Main Authors: Dittrich, Ernő, Klincsik, Mihály, Somfai, Dávid, Dolgos-Kovács, Anita, Kiss, Tibor, Szekeres, Anett
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.04.2021; Springer Nature B.V
• Subjects: Aquatic Pollution; Artificial wetlands; Atmospheric Protection/Air Quality Control/Air Pollution; Dispersion; Distribution functions; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental science; Exact solutions; Gravel; Normal distribution; Plants; Research Article; Streams; Transport processes; Velocity; Waste Disposal, Fluid; Waste Water Technology; Water Management; Water Movements; Water Pollution Control; Wetlands; Fréchet distribution; Subsurface flow constructed wetlands; Hydraulic variability inside the constructed wetland; Transport processes; Divided convective-dispersive transport (D-CDT) model; Inverse Gaussian distribution; Tracer test
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-020-10965-z

This paper offers a novel application of our model worked out in Maple environment to help understand the very complex transport processes in horizontal subsurface flow constructed wetland with coarse gravel (HSFCW-C). We made tracer measurements: Inside a constructed wetland, we had 9 sample points, and samples were taken from each point at two depths. Our model is a divided convective-dispersive transport (D-CDT) model which makes a fitted response curve from the sum of two separate CDT curves showing the contributions of the main and side streams. Analytical solutions of CDT curves are inverse Gaussian distribution functions. This model was fitted onto inner points of the measurements to demonstrate that the model gives better fitting to the inner points than the commonly used convective-dispersive transport model. The importance of this new application of the model is that it can resemble transport processes in these constructed wetlands more precisely than the regularly used convective-dispersive transport (CDT) model. The model allows for calculations of velocity and dispersion coefficients. The results showed that this model gave differences of 4–99% (of velocity) and 2–474% (of dispersion coefficient) compared with the CDT model and values were closer to actual hydraulic behavior. The results also demonstrated the main flow path in the system.