Biomass and Hydrocarbon Production by Botryococcus braunii Using Supplemented Secondary Treated Wastewater

Abstract

The treatment of wastewater has been traditionally done by physical, chemical and biological process. A sequence of experiments was carried out to determine the best concentration of secondary treated wastewater that could be used as growth medium for B. braunii. It was found that 50% (v/v) of treated wastewater and 50% (v/v) of modified BG11 medium was adequate for microalgae growth. Different concentrations of three salts : sodium nitrate, ferric citrate and dipotassium phosphate were tested using central composite design (DCCR), and dipotassium phosphate was found to be statistically significant at 0.12 g·l-1 of this salt. Optimization of CO2 concentration and light intensity showed that 70µ mol·m-2s -1 of light intensity produced biomass concentration of 1.77 g·l-1 with 21.6% of hydrocarbons. The qualitative and quantitative identification of hydrocarbon constituents generated was performed by external standard in gas chromatography. Calibration curves were composed of hydrocarbons from 5 at 32 carbons chain.