Economical Approach to Treatment of Soluble and Particulate As, Cu

21 Economical Approach to Treatment of Soluble and Particulate As, Cu, Zn, and Cr in Stormwater Runoff to Meet BCWQGs AW Elena Ranyuk, Stormtec Filtration Industrial and commercial outdoor yard space is commonly exposed to rainwater which can result in the contamination of stormwater runoff depending on the industrial activity on site. Heavy metals are one of the most common contaminants found in stormwater. Solutions presently available for removal of heavy metals from stormwater down to ppb levels as specified in BCWQGs often imply either large capital investment or high operational costs. Stormtec’s phased approach presents an economical alternative to treatment of metal contaminated runoff. Its typical process is comprised of two stages. Stage I is a lower cost primary treatment using chemical precipitation. Stage II is a secondary treatment utilizing adsorbents and/ or ion exchange resins. Reduction of both dissolved and particulate metals in Stage I increases lifespan of the media used in Stage II several-fold, significantly reducing operational costs. Stormtec will present a case study on treating soluble and particulate As, Cu, Zn and Cr in stormwater runoff at an industrial facility in British Columbia. Since no two projects are alike, Stormtec conducted a series of bench tests combined with optimization on site to determine the most optimal process for the site. First, chemical precipitation of metals was optimized by testing different chemicals, chemical ratios and pH points with the objective of simultaneously reducing all of the targeted contaminants to a certain target level (Stage I). Second, the potential of various adsorbents to further reduce metals was evaluated, and, consequently, two adsorbents were selected for Stage II implementation. Implementation in two stages allowed Stormtec to successfully treat contaminated runoff containing As, Cu, Zn, and Cr in varying concentrations of up to hundreds of ppb to meet BCWQGs AW Freshwater standards. To date, Stormtec has treated over one million gallons of contaminated runoff meeting the guidelines for all metals. Currently, the system performance is closely monitored to determine longevity of the adsorbents required for accurate forecast of media consumption. Delegates will be able to learn from Stormtec’s experience and apply the knowledge to their own water treatment challenges.

Elena Ranyuk, PhD Elena Ranyuk is the Technical Director at Stormtec Filtration. She has a PhD in Organic Chemistry and an MBA in Management of Technology. She has worked for over seven years at the leading research centers in Canada, France and Russia. During this time she led several interdisciplinary research projects ranging from the synthesis of novel materials for removal of heavy metals from water to development of cancer diagnostic and therapeutic agents. Elena’s current professional interests include contaminated site remediation and innovative stormwater treatment technologies. She currently serves on the board of the British Columbia Environmental Industry Association (BCEIA).