PAHs Removal from Urban Storm Water Runoff by Different Filter Materials

Abstract

Urban storm water runoff is contaminated as deleterious materials wash from roadways, parking lots, and open spaces, and the subsequent discharge into surface water sources, such as lakes, can pose adverse effects on public health and the environment. Oil leaks and spills on roadways and parking lots can contain toxic polycyclic aromatic hydrocarbons (PAHs) that can be washed by storm water runoff. Although many best management practices have been developed to treat urban storm water, in-ground filter systems can be best suited in urban site-constrained settings. This paper investigates the effectiveness of different permeable inorganic materials as filter media for the removal of PAHs from storm water runoff. Several series of batch experiments were conducted using four different filter media (calcite, zeolite, sand, and iron filings) and synthetic storm water containing representative PAHs (naphthalene or phenanthrene) at different initial concentrations. The PAH removal and system chemistry in terms of pH, oxidation-reduction potential (ORP), and electrical conductivity (EC) were determined. All of the filter media possessed porous structure and surface characteristics that allowed adsorption and removal of the selected PAHs from the storm water runoff to more than 90%. Calcite and zeolite increased the pH and reduced the ORP and EC significantly as compared with sand and iron filings. Overall, this study demonstrated that the selected filter media have great potential to remove PAHs from urban storm water runoff.