An Innovative and Rapid Method of Assessing Particle Shape and Size in Stormwater Runoff

Over the last several years, the USEPA has listed particulates as the largest source of pollutants to water bodies in the United States. This makes an understanding of the nature and composition of sediments a critical component of water quality studies. Whereas large sediments can be quantified using standard sieves, the same cannot be said of medium to fine sediment, which constitutes the primary source of pollution in urban stormwater runoff. This paper focuses on the use of new technology in the water quality industry with emphasis on assessing the ability to quantify fine sediment from urban stormwater runoff. The technology was assessed using influent and effluent samples from a stormwater treatment system. Subsamples were transported through this fluid imaging technology and the results from the influent and effluent samples compared. The results are also compared with the suspended sediment concentrations (SSC) from the collected samples. The particle imaging system was effective at differentiating changes in gradation between the influent and effluent samples and also provided information on the geometry of the particulates in the sample. The use of this technology has proven to be valuable and could be employed as a means of quickly assessing the performance of treatment devices for fine particulate removal. It has the added advantage of providing information on the shape and transparency of a particle which for the water quality industry could be a good differentiator between inert sediments and other materials common in stormwater runoff.