Inflow and outflow event mean concentration analysis of contaminants in bioretention facilities for non-point pollution management

In order to establish a sustainable stormwater management system, research has focused on Low Impact Development (LID) facilities. This study analyzed the runoff reduction efficiency and pollutant removal efficiency in Bioretention facilities. The results of the study were analyzed using long-term monitoring data over three years, and experiments were carried out using real rainfall and artificial rainfall to simulate various rainfall conditions. The Event Mean Concentration (EMC) is a pollutant concentration value for rainfall events. Based on the analysis of inflow and outflow EMC, TSS was found to have the largest reduction. The reduction ratio for efficiency about pollutant and run-off(%) was monitored for 3 years and more. The itemized data was plotted on chart annually. Based on the annual average pollutant removal efficiency values, all the pollutant removal efficiency values, except the runoff reduction efficiency, showed a decrease in efficiency over time. Based on the results of the study, the necessity for proper maintenance was confirmed. The results of this study are expected to inform further research on non-point pollution reduction facilities. •This experiment was conducted over three years to utilize long-term data.•Monitoring was performed under various rainfall conditions.•The average pollutant removal efficiency for all parameters was greater than 80%.•Efficiency of TN and TP inorganic substances that promote eutrophication was also high.•Efficiency for each year, all formed a trend line of decreasing efficiency.