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h <br /> Hydro"'le,n o South Relief Canal Algal Turf Scrubber@ Pilot Program <br /> 1 . INTRODUCTION <br /> A number of treatment technologies have been developed that provide nitrogen and <br /> phosphorus ( nutrient) removal from stormwater ( nonpoint source ) and/or advanced level <br /> nutrient control for wastewater ( point source) effluents or sidestreams . Plant based <br /> biological systems that include ( i ) treatment wetlands and ( ii ) managed aquatic plant <br /> systems ( MAPS ) have been applied to both point and non - point source applications , while <br /> bacteria based biological systems including ( iii ) biological nutrient removal ( BNR ) , ( iv) <br /> enhanced biological phosphorus removal ( EBPR ) , and (v) the modified Renphosystem , <br /> among others are applied almost exclusively to wastewater associated point source <br /> applications . <br /> Managed aquatic plant systems ( MAPS ) have been developed , and are now commercially <br /> available . MAPS dynamics revolve around direct nutrient uptake by cultivated aquatic <br /> plants and subsequent removal and recovery through harvesting and processing of the <br /> plant biomass . This approach offers reduced land area requirements when compared to <br /> " passive" treatment wetlands , while providing quantifiable removal , recovery and reuse of <br /> captured nutrients and effective enhancement of water quality through increased dissolved <br /> oxygen levels and attenuation of other pollutants , such as metals and hydrogen sulfide . <br /> One specific MAPS technology known as The Algal Turf Scrubber® or ATSTM is being <br /> considered by Indian River County ( COUNTY) as a reasonable approach to management <br /> of a combined wastestream composed of 1 ) about 1 MGD Reverse Osmosis ( RO ) <br /> concentrate from a water treatment unit owned and operated by Indian River County <br /> Utilities and 2 ) about 10 MGD of canalized stormwater associated with the Indian River <br /> Farms Water Control District ( IRFWCD ) South Canal . The RO concentrate is a mineralized <br /> water with a conductivity of about 6 , 000 microS/cm , and comparatively low nutrient levels . <br /> Indian River County is coordinating with the FDEP to resolve concerns regarding the <br /> concentrate related to nutrient and salinity loads and intermittent toxicity revealed through <br /> bioassays with Mysid shrimp ( Mysidopsis bahia) . ' The canalized stormwater typically is <br /> characterized by lower conductivity levels ( < 1 , 000 microS/cm ) but higher nutrient <br /> concentrations . Presently , management requirements associated with the RO concentrate <br /> are delineated with an FDEP Permit 31 FL0037940 and the associated Consent Order 08- <br /> 1661 . The requirements for nutrient reduction within the South Canal stormwater flows are <br /> associated with the recent Total Maximum Daily Loads (TMDL) determinations . 2 <br /> The Algal Turf Scrubber® or ATSTM is an engineered system composed of a sloped <br /> expanse of high density polyethylene ( HDPE) geomembrane overlain with a synthetic grid <br /> matrix . Water is distributed across the sloped floway in a shallow laminar flow , which <br /> provides ideal conditions for the development of an algal turf community ( Illustration 1 ) . <br /> Cultivation of the algal turf is sustained through periodic harvesting , which facilitates <br /> general improvement of water quality , including predictable reduction of nitrogen and <br /> Consent Order 08- 1661 executed September 19 , 2008 . <br /> 2 Total Maximum Daily Load for Northern and Central Indian River Lagoon and Banana River Nutrients and <br /> Dissolved Oxygen April 2007 . EPA Region IV . <br /> Plan of Study <br />