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i <br />- i <br />elr�ar� <br />FILTRATION DEVICES <br />Proprietary systems used as an example only - NOT an endorsement <br />Design Criteria: <br />► Pollutants of interest for reduction <br />► Desired removal efficiency <br />► Design flow or volume, site constraints on <br />size, desired location of treatment unit <br />► Pre-treatment requirements <br />► Installation and maintenance costs, life of <br />unit <br />Benefits: <br />► Units are typically underground or within <br />existing structures and do riot consume <br />much site space <br />► Filtration devices can be customized to <br />reduce a specific pollutant of concern <br />► Can often be easily incorporated into fully <br />developed sites <br />► Can be used for pre-treatment prior to <br />infiltration practices <br />► Relevant for use on industrial sites because <br />filters can remove pollutants such as metals <br />and oils <br />Limitations: <br />► Efficiency has not been widely tested <br />► Each type of unit has specific design <br />constraints and limitations for use <br />► Can be more costly that other treatment <br />methods <br />Treatment may be greatly reduced if <br />frequent maintenance is not condl_icteca <br />► Subject to freezing in cold climates <br />Definition: <br />Filtration devices (inserts_) allow <br />stormwater to pass through <br />filter media which are designed <br />to reduce specific stormwater <br />Pollutants, but primarily solids <br />and oils. Pollutants are captured <br />physically or through sorption onto <br />the filter media. Filters may either <br />be inserts that are retrofitted into <br />existing catch basins or manholes, <br />or stand alone units supplied by a <br />manufacturer. <br />Water Quality (Valla) <br />NA Channel Protection (V CP) <br />NA Overbank Flood Protection (V Plo) <br />NA Extreme Flood Protection (V P,uo) <br />NA Recharge Volume (V RE) <br />POLLUTION REMOVAL <br />ZffigX� P <br />Total Suspended Solids <br />*"x x=3r Nutrients - Total Phosphorus/ <br />fr4-� Total Nitrogen <br />Metals Cadmium, Copper, Lead, <br />" and Zinc <br />Pathogens - Coliform, Streptococci- <br />MW.aY a. E. Coli <br />+ Toxins Chloride, Hydrocarbon, <br />Pesticide <br />" target pollutants - actual percentage of pollutant removal vanes with <br />Infiltration <br />Screening/ Filtration <br />Temperature Control <br />Settling <br />4 , ' <br />Evaporation <br />Transpiration <br />x:. <br />Soil Adsorption <br />Biological/ Micro. Uptake <br />POLLUTION REMOVAL <br />ZffigX� P <br />Total Suspended Solids <br />*"x x=3r Nutrients - Total Phosphorus/ <br />fr4-� Total Nitrogen <br />Metals Cadmium, Copper, Lead, <br />" and Zinc <br />Pathogens - Coliform, Streptococci- <br />MW.aY a. E. Coli <br />+ Toxins Chloride, Hydrocarbon, <br />Pesticide <br />" target pollutants - actual percentage of pollutant removal vanes with <br />