Assessment of subsurface migration and simultaneous removal of Carbendazim in simulated constructed wetland through physical and numerical modeling

Abstract

Indiscriminate disposal of hazardous waste into land generates harmful effects in the lithosphere. Carbendazim is widely used to prevent fungal diseases in agricultural fields and industries, such as paper, leather, and paint, in an uncontrolled manner and is reported as a possible human carcinogen when consumed. Therefore, it is urgently needed to find effective methods to remove Carbendazim from wastewater. In this investigation, Lightweight Expanded Clay Aggregate (LECA) and silty sand have been explored as alternating bed materials in a Constructed Wetland with Chrysopogon zizanioides for phytoremediation to attenuate Carbendazim from wastewater. The hydraulic conductivity of the soil and LECA were found as 1.63 × 10−7 m/s and 1.12 × 10−3 m/s, respectively. Batch adsorption test data exhibited that Langmuir and Pseudo second-order were the best fitting isotherm and kinetic models in both cases, with Regression Coefficient (R2) values of 0.99 for all also LECA had a high adsorptive capacity for the depletion of Carbendazim. Constructed Wetland study with LECA and phytoremediation using Chrysopogon zizanioides yielded maximum removal efficiency of Carbendazim in the range of 96–99.6 %, which corroborated closely with the results from the HYDRUS model. Results demonstrate the combined efficacious use of LECA and Chrysopogon zizanioides to abate Carbendazim from wastewater, which can be recommended as a cost-effective solution for its field-scale applications.