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Algae are being investigated for large scale production of biofuel, with much research focused on phytoplankton as single species. However, multiple environmental benefits may be recognized through the use of large-scale, algal based, water treatment technologies when biomass residuals are able to be converted to biofuel. The Algal Turf Scrubber® (ATS™) is a treatment process that uses periphytic algae to reduce nutrient pollutants (nitrogen and phosphorus) from stormwater runoff and natural water bodies. Naturally occurring algal species are cultivated through system design and operational processes, which includes routine harvest of the algal biomass. Harvesting maintains the system in an accelerated growth phase, thereby increasing nutrient removal potential, and creating a sustainable process area. Commercial scale ATS™ systems have been shown to achieve production rates of 20-40 dry g/m2-d of algae, while providing phosphorus areal removal rates up to 200 lbs/ac-yr and nitrogen removal rates up to 4,000 lbs/ac-yr. These high removal rates allow for greater nutrient reduction in a smaller footprint than other biological water treatment technologies. Periphyton based systems such as the ATS™ are unique in that they offer high rates of algal productivity even in low nutrient waters. From a water treatment perspective, periphyton based systems offer high areal removal rates and sustainability. Cultivated algal biomass has the potential to add an energy benefit to these systems, which would offset treatment costs, thereby making restoration efforts more affordable to communities charged with such efforts. |