Modeling Subsurface Upflow Wetlands Systems for Wastewater Effluent Treatment

Constructed wetlands have been popular in ecological engineering regime; yet, modeling the physical, chemical, and biological processes within these wetlands is a long-standing challenge in the past decades. In concert with our field-scale pilot testing of a new-generation subsurface upflow wetland (SUW) system, this article highlights an advancement of modeling the SUW system with a layer-structured compartmental simulation model. This is the first wetland model of its kind to address the complexity between plant nutrient uptake and medium sorption. Such a system dynamics model using STELLA as a means for a graphical formulation was applied to illustrate the essential mechanism of the nitrification and denitrification processes within a sorption medium-based SUW system, which can be recognized as one of the major passive on-site wastewater treatment technologies in this decade. Model calibration and validation received fairly good R-squared values of 0.9998 and 0.9644, respectively. Such good agreement with the measured data confirms that the developed system dynamics model may provide a reliable tool for designing this particular type of constructed wetland. This work also entails the significant movement of linking green building with green infrastructure as part of the urbanization for nature.