Wastewater was collected from the Utah State University Caine Dairy Farm evaporation pond. Characteristics of the water and the produced algae-based biofilm are summarized in Table 1. Turbidity of the water was measured at 890 NTU (Hach 2100Q turbidimeter). Algae biomass inoculum for the laboratory RABRs was collected from the pilot scale RABR systems currently operating at the Logan City wastewater treatment facility, a 460 acre (1.86 km2) open lagoons system . Visual microscopy of the pilot scale RABR based biofilm indicated that the collected algae biomass contained a variety of algae species, with Pseudanabaena, Oscillatoria, and Chroococcus as the predominant species. The biomass was then cultivated on a cotton rope substratum in shaker flasks using dairy wastewater as the nutrient source before application to the RABR system to allow the culture to adapt to the nutrient source. The carbon:nitrogen:phosphorus molar ratio of the adapted biofilm was measured to be 85:16:1, which is comparable to other algae-based systems .Table 1Composition of influent Caine Dairy wastewater and cultivated biomass from the RABR system. (Analysis by Chemtech-Ford Laboratories – Sandy, UT)Chemical compositionWatera (mg L-1)Biomassb (mg kg-1 dry wt.)Total organic carbon1200648500Total nitrogen155c 140400Total phosphorus1219100Aluminum7.67776Boron1.73132Barium0.6375.7Cobalt0.031.96Chromium0.4245.3Copper3.0585.2Iron6.80624Manganese0.67107Molybdenum0.0927Sodium46023455Nickel0.2524.1Lead0.056.41Silica1065572Strontium1.18125Zinc1.15116 aDairy wastewater influent stream bProduced algae-based biofilm cTotal Kjeldahl Nitrogen (Organic nitrogen, ammonia, and ammonium)