Microalgae bioremediation and CO2 fixation of industrial wastewater

Abstract

The present work evaluates the bioremediation potential of the microalgae Chlorella sp. cultivated in industrial wastewaters of a metallurgy facility for CO2 fixation. Its growth in wastewaters was investigated experimentally and growth rate was determined based on different dilutions. Taguchi's experimental design was carried out and values found in laboratory were compared to those of a mathematical model adjusted based on growth rate. Process efficiency was evaluated to reduce organic load, nutrient consumption, and cell count during the initial and final stages via microscopy. After the biological treatment, reduction percentages of 99% for COD (Chemical Oxygen Demand) and 95% for SS (Sedimentable Solids) were achieved, in addition to 86% and 93% of nutrient and cyanide removal, respectively, and average CO2 biofixation of 0.1854 gL-1d-1.These values are close to those found in literature for other cultivation media. It was also observed that biomass productivity and CO2 fixation data are in agreement with those obtained in other studies, thus evidencing the efficiency of Chlorella sp. microalgae and its high photosynthetic capacity.

Keywords

• Effluent
• Chlorella sp.
• Bioremediation
• CO2 biofixation