# Environmental Chlorine Pollution Mitigation Using Material–Pollutant Interactions and Field-Scale Applications

## TL;DR

This paper explores how rain gardens can reduce chlorine pollution in stormwater using waste materials, showing promising results for sustainable environmental solutions.

## Contribution

The study demonstrates the effectiveness of rain gardens using waste materials for chlorine retention in stormwater treatment.

## Key findings

- Rain gardens using waste materials achieved an 82.5–87% chlorine retention efficiency.
- Infiltration coefficients were comparable to sand–gravel substrates in both lab and field tests.
- Granulometric analysis confirmed the suitability of material fractions for filtration.

## Abstract

Nature-based solutions, including green infrastructure (GI), are considered sustainable tools for stormwater treatment. GI elements (rain gardens, green roofs, etc.) are increasingly applied as integrated approaches for climate change mitigation and environmental pollution reduction. This study focused on investigations of rain gardens for reducing stormwater polluted by residual chlorine after the disinfection of outdoor spaces. Laboratory (column test) and field tests were carried out to evaluate the infiltration capacities of an experimental rain garden model, as well as its efficiency for retaining residual chlorine. The experiments were conducted using simulated rain garden layers composed of waste materials that remained after different production processes. The average infiltration coefficient values obtained were 2.55 × 10−5 m/s, 2.45 × 10−5 m/s, 2.24 × 10−5 m/s, 3.4 × 10−5 m/s, 1.28 × 10−5 m/s, 1.84 × 10−5 m/s (laboratory test), and 1.39 × 10−5 m/s (field test). These values correspond to the characteristics of sand–gravel substrates. A chlorine retention efficiency of 82.5–87% was obtained. Granulometric analysis confirmed fraction size suitability for rain garden filtration. This research indicates the potential of rain gardens for reducing stormwater pollution, providing a basis for future research and practical implementation.