Organic micropollutant removal in stormwater: a review of treatment performance

Abstract

Stormwater runoff is increasingly recognized as an alternative water resource, but organic micropollutant (OMP) contamination poses challenges to its safe harvesting. This study systematically reviews stormwater treatment systems to assess their effectiveness in OMP removal and their potential to mitigate associated risks. Among nature-based solutions (NBS), biofilters demonstrate high removal efficiency (>80%) for most tested OMPs. A significant positive correlation was found between hydrophobicity (log K_ow) and removal efficiency (p < 0.05; Pearson and Spearman correlation), suggesting adsorption as the dominant mechanism for hydrophobic compounds, while biodegradation plays a key role in removing many hydrophilic OMPs. Key design features, such as vegetation, submerged zones, and filter media amendments (e.g., biochar, compost), further enhance treatment performance. Constructed wetlands generally achieve removal rates above 60% mainly for hydrophobic OMPs, though challenges remain for emerging refractory pollutants such as perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). Porous pavements are effective for polycyclic aromatic hydrocarbons (PAHs) and total petroleum hydrocarbons (TPHs), particularly with adsorptive materials and geotextile layers, but limited studies restrict broader implementation. Ponds and swales exhibit variable performance, effectively treating PAHs and pesticides but showing lower efficiency for pharmaceuticals and plasticizers. Advanced oxidation technologies demonstrate strong potential, achieving >80% removal for tested PAHs, pesticides and corrosion inhibitors within minutes to hours, making them suitable for post-treatment applications. Despite progress, data gaps hinder robust assessments of design and operational parameters. Future research should focus on optimizing nature-based solutions (NBS) through smart sensors, real-time control strategies, and hybrid approaches integrating advanced oxidation technologies to enhance OMPs removal in stormwater harvesting systems.