Uso de Chlorella vulgaris em tratamento de águas residuárias associado à produção de biodiesel - um estudo computacional a partir do caso do rio Tietê, São Paulo

Abstract

This document consists of a simplified simulation of the microalgae Chlorella vulgaris growth utilizing urban wastewater as media. It also considers the construction costs of a wastewater treatment plant (WWTP) adapted to utilize such organisms in the process of wastewater cleansing as well as the profits that could come from such treatment. Therefore, secondary data was collected from scientific literature and governmental documents made available on-line by the government of São Paulo. These were used in conjunction with the Michaelis-Menten equations of microbial growth and the software COMSOL Multiphysics, ver. 5.3., in order to allow a visualization of the impacts of growing these specific algae on wastewater. The case study was made utilizing the data collected from the Ambiental Company of the São Paulo Estate (CETESB) and the models inserted in COMSOL to evaluate nitrogen and phosphorus removal triggered by the microalgae’s growth. The results seem to point that C. vulgaris culture is well capable of removing nitrogen to acceptable levels but the phosphorus removal was found inefficient. The resulting economic indicators also seem to point out that investing in this kind of wastewater treatment could be very profitable, despite the lack of analysis by brazilian researchers. Lastly, the document points out its shortcomings, especially When it comes to the simplifications that were needed to allow the simulations to work due the complexity of biological systems.