Cultivo de microalgas em efluente de tratamento anaeróbio de esgoto

Abstract

The production microalgal biomass for biofuels is a promising alternative, and the use of effluent wastewater treatment is a strategy to reduce production costs utilizing available nutrients in these effluents. In this work were isolated from effluent wastewater treatment six microalgae identified as Desmodesmus sp. L02; Chlorococcum sp. L04; Coccomyxa sp. L05; Chlorella sp. L06; Scenedesmus sp. L08 and Tetradesmus sp. L09. The Chlorella sp. L06 showed survival greater than 90% in natural UASB reactor effluent (EFN). The dry biomass of isolates culturing in UASB effluent autoclaved (EFA) showed mean 28,7% of total proteins, 15,4% of the total lipids and 14,8% of total carbohydrates. After removal of micralgal biomass culturing in the laboratory by the addition of 250 mg/L of aluminum sulfate was observed removal values of 59,2% and 93% of nitrogen and 79,1 to 95,4% phosphorus by isolates Desmodesmus sp. L02 and Tetradesmus sp. L09, respectively. The Chlorella sp. L06 showed highest growthing rate based on chlorophyll-a (9.726,4 g/L.d) when culturing in EFA with addition of 0,25% NaHCO3. Operational tests were also conducted in a semi-closed plastic tubular photobioreactor (FBR-TPSF) for production of microalgal biomass in UASB effluent under natural conditions of temperature and luminosity. The highest yield of biomass, 0,17 Kg/m3 .d was recorded with tests in FRB-TPSF when worked with TDH=1d without recirculation. The dried biomass of the treatments 1d, 2d, 2dx4Q e 2dx8Q showed 25,1%, 23,3%, 11,1% and 7,7% total proteins, 13,5%, 11,0%, 10,2% and 10,5% total lipids and 9,7%, 6,8%, 13,4% and 16,5% total carbohydrates, respectively. The removal of the biomass cultivation FBR-TPSF by coagulant showed removal efficiency to phosphorus, reaching maximum value of 95,1%