A tracer study for assessing the interactions between hydraulic retention time and transport processes in a wetland system for nutrient removal

Abstract

In this study, a new-generation subsurface upflow wetland (SUW) system packed with the unique sorption media was introduced for nutrient removal. To explore the interface between hydraulic and environmental performance, a tracer study was carried out in concert with a transport model to collectively provide hydraulic retention time (7.1 days) and compelling evidence of pollutant fate and transport processes. Research findings indicate that our pollution-control media demonstrate smooth nutrient removal efficiencies across different sampling port locations given the appropriate size distribution conversant with the anticipated hydraulic patterns and layered structure among the sorption media components. The sizable capacity for nutrient removal in this bioprocess confirms that SUW is a promising substitute for an extension of traditional on-site wastewater treatment systems.

The Flow Field Distribution of Subsurface Flow Constructed Wetlands

“…Particle size directly decided the matrix permeability, pollutant adsorption rate, entrapment ability, and the matrix permeability was the main factor influence on flow field distribution. The low permeability coefficient matrix of pollutant removal rate was high, and corresponding hydraulic load was small, Water flow was difficult passed through the bottom layer, which was easily caused surface flow and short flow, reduced effective utilization rate of matrix [22]. On contrary, for the larger particle size with high permeability coefficient, substrate adsorption performance degradation, micraobial adhesion area was small and effluent suspended solids was high, but it was not easy clogging as the high permeability coefficient.…”