Avaliação do ciclo de vida da produção de biomassa de microalgas em meio efluente.

Abstract

The microalgae have been indicated to the fixation of carbon biofuel production. Its use has a lot of advantages, such as high photosynthetic efficiency, great biomass production and faster growth to energetic means compared to other cultures. Thus the production methods are based in adequate conditions to growth in photosynthetic ambient and steps of separation of biomass, drying and biomass byproducts obtainment, resulting in many production methods that requires evaluation about the environmental impacts that may be caused. The Life Cycle Assessment (LCA) methodology helps this process. Therefore the objective of this paper was to inventory and analyze the life cycle of microalgae production in effluent treatment plant in raceway system aiming at production of biofuels, to pilot scale, using the SimaPro 7.3.2 software. According to the experiments result, the main category of environmental impact was “carcinogenic”, which is categorized as “Damage to Human Health”. In this category it can observed aspects of life such as number of years lost or lived with disability. The obtained result is due to high electrical energy consumption. Since three scenarios with different production conditions (considering cultivation, separation and drying) were realized, it was possible to define that the lowest environmental impact occurs in scenario two. In this scenario the cultivation is realized using aeration system and media agitation by blower or paddle wheels in the raceways (same impact in both of them), followed by separation by flocculation with the addiction of sodium hydroxide and the use of a dryer. The total impact in this scenario was 1,56.10-2 DALYs (Disability Adjusted Life Years).