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An insitu passive treatment pilot system was installed in the ground to capture rooftop storm runoff from an aluminum smelter. The treatment system was designed to reduce runoff and pollutants, decreasing water treatment costs compared to current end-of-pipe methods. This filtration system has been successful at an aluminum smelter in a warmer climate and must be tested to determine its effectiveness at this site before a full scale system can be constructed. The system’s performance in cold climate conditions, especially during spring snow melt, is of particular interest. The filtration system consisted of layers of gravel, topsoil, and grasses. The initial first flush, which typically contains higher concentrations of contaminants, was directed through the gravel layer to a treatment area while subsequent runoff was absorbed by the soil and grasses. Samples were taken using an automated sampler in order to record the flow of water through the system as a rain event progressed. Contaminant concentrations were determined in samples taken from the filtration site and control site, which consisted of pavement with the same dimensions as the filtration system. Preliminary results show flow was reduced by half or greater, turbidity was reduced, pH was closer to neutral, and ammonia concentrations reduced tenfold in filtered water compared to the control. There was an increase of fluoride concentrations in filtered samples. Aluminum analysis of samples and total suspended solids tests have yet to be run. Further analysis of samples must be conducted to have a more complete picture this system’s effectiveness.
1 Class of 2010, Environmental Engineering, Clarkson University, REU, Grimberg and Holsen
2 Department of Civil and Environmental Engineering, Clarkson University
3 Department of Civil and Environmental Engineering, Clarkson University
4 Environmental Department, Alcoa Massena Operations
5 Environmental Science and Sustainable Technology, Alcoa Technical Center