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The first water quality BMP is the pretreatment wet pond. Its primary purpose is to capture suspended solids and floatables at the head of the treatment system. An existing pond will be converted to the pretreatment pond. It will likely have a short detention time (a few hours) . Nevertheless , it will capture a large percentage of the canal water ' s heaviest suspended solids . The pretreatment pond will be approximately 4 .4 acres in water surface area and the banks will be planted with a littoral zone . The second BMP is the 6 acre ATSTM which is the heart of the treatment system. The ATSTM consists of a sloped, geomembrane liner overlain with a grid on which algae grow. Nutrient enriched waters are discharged onto this structure and an algal turf is cultured. The algal turf is comprised of dense mats of small anatomically simple periphytic or benthic algae less than several centimeters high. These turfs are very effective at removing nutrients, color, and a variety of pollutants found in stormwater and freshwater seepage. Wave motion is introduced to enhance the exchange of metabolites between the algal cells and the water medium. The Algal Turf Scrubber® will be similar to the unit processes currently in operation at the HydroMentia, Inc . demonstration project near Okeechobee, Florida. The biomass produced by the ATSTM must be harvested periodically to remove the collected nutrients from the treatment system and to avoid succession of the algal mat to less desirable algae species such as macroalgae and macrophytes . Harvesting is accomplished efficiently using a small all-terrain vehicle dragging a scraper over the algal mat. The scraper dislodges the algae which is washed into a collection flume where it is physically removed from the flow by a mechanical rake at a centralized harvesting location. The harvested biomass is then conveyed to a bunker where it is available for further processing. A single operator can harvest over one acre of ATSTM per hour, resulting in a harvest of about 5 wet tons or 0 . 5 dry tons . The recovered plant biomass can be efficiently composted into a high-grade product with a typical analysis as shown below. Typical Analysis of Harvested Product -Nitrogen N 2 . 0 - Phosphorus P2O5 1 . 0 Potassium KZO 0 . 5 Sulfur S 0 . 2% Calcium Ca 1 . 5 °,x'0 - Magnesium MG 0 . 25 % Moisture 40% The harvested plant material, which is typically 20-30 percent protein, may also be processed into a livestock feed product. The ATSTM process is based partly on agricultural operations and the IRFWCD has a number of agricultural operations within its boundaries . If desired, effluent from the ATSTM could be used to irrigate the orange groves adjacent to the site as a demonstration project of reuse . The organic material harvested from the system could also be composted and used to replace some of the fertilizer needed for the citrus operation. One of the assessments to be completed is an evaluation of the ability of this system to create a reusable waste stream as an alternative disposal technique to simply composting . The third BMP is the 4 .7 acre effluent polishing pond and it will remove any algae escaping the ATSTM, together with some of the remaining nutrients . This is also an existing pond whose banks will be modified to accommodate littoral plantings. The pond will harbor a large population of fish, insects, waterfowl, and other animals . A smaller and fourth BMP is the 3 . 2 acre passive wetland system. This will receive some of the polishing pond ' s effluent and further reduce the remaining pollutant load. A very high quality wetland system will be attainable under these circumstances and it will offer additional refuge to many birds, amphibians, and animals . Together with the ATSTM , it will provide a unique educational opportunity for Indian River County ' s citizens . Water from the Lateral C Canal will be pumped from downstream of the existing radial gate water control structure into the pretreatment pond. The side slopes of this existing pond will be modified to have a shallower slope to allow for littoral zone planting . Water from the pretreatment pond will then be pumped to the ATSTM DEP Agreement No. G0143 , Attachment A, Page 6 of 9