Effects of Vegetation and Saturated Zone in Cascaded Bioretention on Enhancing Nutrient Removal

Bioretention is a water management practice that increasingly being applied for runoff quality control. Although previous studies have used some techniques to improve nutrient removal, nutrients still leach out. Therefore, this study Cascaded (CB) by connecting three columns in series. The planted Column was retrofitted adding subsurface drainage module (SDM) below the gravel layer create dual saturated zone. This aimed investigate effect of number treatments, vegetation, and modified zone on enhancing removal from agricultural understand mechanisms. efficiencies NH3-N, NO3-N, NO2-N, TN improved 89.8%, 49.7%, 49.2%, 53.4%, respectively. only negative ON, which significantly decreased incorporating vegetation Increasing treatments enhanced ON while maintaining stable other nitrogen compounds. However, phosphorus less sensitive increasing treatments. Nitrogen could be different processes such as nitrification, denitrification, mineralization, assimilation plant uptake, Anammox. complicated, adsorption infiltration are likely main