INNOVATIVE TREATMENT METHOD FOR REMOVING ORGANIC CONTAMINANTS FROM ROADWAY RUNOFF

The quality of many surface and coastal waters is negatively impacted by stormwater runoff pollution from urban areas and roadways. Stormwater runoff may contain elevated concentrations of heavy metals, petroleum hydrocarbons, nutrients and other pollutants. These compounds are quite difficult and expensive to clean-up once discharged into rivers or the ocean. Therefore, prevention of contamination is the most effective way of resource protection. We have conducted a series of laboratory experiments with simulated roadway runoff and wood fibers. The experiments were carried out under static (=no-flow) and dynamic (=flow) conditions to simulate natural systems as close as possible. Our experiments demonstrate that the presence of wood in water significantly reduces the concentration of polycyclic aromatic hydrocarbons, PAH, which are some of the most problematic organic pollutants found in roadway runoff. For example, after of flushing more than 1 gr of pyrene (equivalent to more than 30 L of pyrene solution) through a column filled with approximately 3 gr of wood fibers, we were able to remove about 80% of the contaminant mass. The contaminant removal was not only very effective, but also remained relatively constant over an extended period of time (30 days). Additional isotherm and desorption experiments were conducted which indicate that the uptake and release of PAH is rate limited. Alltogether, the results indicate that wood fiber could be of use for possible applications in wastewater treatment or as best management practices in roadway construction.