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Urban Scale Algae Turf Scrubbing

Agriculture, home gardens, and the increased use of fertilizers increase the number and impactof fish kills in the Chesapeake Bay; these fish kills threaten the local economy and can result in negative effects on human and fish health. The design of the residential-scale Algae Turf Scrubber (ATS) system utilized PVC piping, which served as a water transfer system and algae water feeder for a communal Chlorella algae screen; LED lights outside of the system served as a lighting bank for the communal algae screen. The initial goal for experimentation was to remove at least 20-30 percent of initial phosphorus and 15- 20 percent of nitrogen loads from the infected waters, while maintaining dissolved oxygen levels above 5 mg/L. Final DO levels were 6.7 mg/L from an original level of 6.2 mg/L. 0.525 mL (milliliters) of nitrogen and 2.8 mL of phosphorus were added were added to 3.5 gallons of dechlorinated tap water. Initial nitrate and phosphate tests, indicated that initial phosphorus levels equated to 1 ppm and initial nitrogen levels, 4.4 ppm. Over the course of two weeks phosphorus loads decreased to 0.2 ppm (an 80 percent decrease) while nitrogen levels remained at 4.4 ppm. The residential-scale ATS can be used to reduce the costs of water treatment through the conduction of point-source nutrient removal, lower total phosphorus levels in the Chesapeake Bay, restore dissolved oxygen to at least 5 mg/L, and prevent toxic algae from blooming and secreting toxins into the Bay.