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

Abstract

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.

Role of constructed wetlands in mitigating the challenges of industrial growth and climate change impacts in the context of developing countries

“…As a result, the enormous onsite space needed to promote CWs in metropolitan areas is severely constrained. While it may seem at first glance that centralized WTSs need less onsite acreage than CWs, Fan et al (2021) found that widespread deployment of WTSs in municipalities may cause a significantly more amount of land usage in upstream operations, which might put further strain on the accessible land resources.…”

Proposing a Wetland-Based Economic Approach for Wastewater Treatment in Arid Regions as an Alternative Irrigation Water Source

“…Constructed wetlands (CWs) are made up of shallow lagoons or channels (depths of less than 1 m) that are planted with local species that are typical of humid areas, in which the decontamination processes take place through interactions between the water, solid substrates, microorganisms, vegetation, and even fauna [24]. Based on the water circulation characteristics, constructed wetlands can be classified into surface and subsurface flows [25]. In contrast to surface flow wetlands, their subsurface equivalents admit higher organic loads, reduce the risk of contact with the population, and prevent the appearance of insects [26].…”