# High Rate Stormwater Treatment for Water Reuse and Conservation--Review
## 6 Conclusions  
GSI is a promising concept that efficiently manages stormwater pollution while promoting greener technologies. Many researchers have documented the fate, impacts, and removal of pollutants in stormwater. Vegetated biofililtration is a popular treatment approach in urban areas, requiring less land than constructed wetlands and making it particularly suitable for local stormwater harvesting solutions. Although both constructed wetlands and biofilters have demonstrated significant potential in reducing pathogen levels, they do not satisfy reuse standards. A number of filter media were successfully used in low-impact development (LID) systems, such as green roofs, bioretention systems, and swales to remove additional pollutants such as nutrients, heavy metals, poly aromatic hydrocarbons (PAHs), and other micropollutants in a consistent manner. High-rate treatment systems offer an opportunity for sustainable urban development by minimizing the demand for municipal water, reducing stormwater pollution, and lowering stormwater discharges. High-rate treatment systems that can be used are media filtration packed with GAC and anthracite, fiber filtration, and membrane filtration. The GAC filter column demonstrated a strong capacity for reducing influent DOC concentrations. It removes most types of organic matter. On its own, the GAC filter achieved an average turbidity reduction of 84%. The anthracite filter did contribute to lowering turbidity levels prior to water entering the GAC filter. Utilizing an anthracite medium filter before GAC filtration serves as a screening mechanism, capturing sediments and pollutants that could otherwise clog the GAC and shorten its lifespan. Although the raw influent stormwater typically exhibited low levels of heavy metals, the GAC filter effectively removed a significant proportion of these metals. Both anthracite and GAC filters were back-washed after each storm event to remove the solids retained. Since the concentrations of heavy metals and organic content in the stormwater were typically low the GAC medium in the filter can be replaced on a biennial basis. This depends \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Sample**} & \multirow{2}{*}{\begin{tabular}{c} **Dissolved** \\ **Organic** \\ **Carbon (LOC)** \\ **mg/L** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Hydrophobic** \\ **Organic Carbon** \\ **(HOC mg/L)** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Hydrophilic** \\ **Organic Carbon** \\ **(DOC) mg/L** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **BIO-** \\ **Polymers** \\ **mg/L** \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} **Hunic** \\ **Substances** \\ **(HS) mg/L** \\ \end{tabular} } & \multirow{2}{*}{\
\begin{tabular}{c} **Building** \\ **Substances** \\ **mg/L** \\ \end{tabular} } & \multirow{2}{*}{
\begin{tabular}{c} **Low Molecular** \\ **Weight** \\ **Substances** \\ **mg/L** \\ \end{tabular} } \\ \hline Stormwater (Raw) & 5.86 & 3.87 & 1.99 & 0.17 & 1.04 & 0.46 & 0.32 \\ \hline GAC Filter & 1.76 & 1.08 & 0.68 & 0.10 & 0.35 & 0.35 & 0.05 \\ \hline Raw rainwater (for comparison) & 1.63 & 1.26 & 1.26 & n.q. & 0.2 & 0.2 & 0.06 \\ \hline \hline \end{tabular}
\end{table} 
Table 11: Organic compound fractions measured by LC-OCD (modified from [PERSON] et al. [54]). on the rainfall intensity. The management of emerging contaminants and microplastics is relatively less understood yet and deserves future attention. The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app15020590/s1](https://www.mdpi.com/article/10.3390/app15020590/s1)]([https://www.mdpi.com/article/10.3390/app15020590/s1](https://www.mdpi.com/article/10.3390/app15020590/s1)). Characteristics of GAC used in Section 5. Table S1. Parameters for the models fits to experimental data for Cu, Pb, and Zn adsorption on GAC. Reference [55] is cited in the Supplementary Materials. Conceptualization, methodology, and formal analysis S.V., J.K. and H.R.