Improving Microalgae-Based Wastewater Treatment: Impact of Organic Carbon and Light Intensity on Pollutant Removal Efficiency

Scenedesmus obliquus , a microalgae extensively researched, is renowned for its potential in biofuel production and wastewater treatment. Organic carbon sources are pivotal in augmenting the growth and metabolism of microalgae in heterotrophic and mixotrophic environments. This study selected several exemplary organic carbon sources to examine their influences on the growth characteristics and lipid accumulation of S. obliquus under mixotrophic conditions. Concurrently, the growth dynamics and pollutant removal efficacy of S. obliquus were assessed when cultivated with organic carbon-acclimated, using actual secondary treated wastewater as the growth medium. The results indicate that various organic carbon can facilitate the growth and lipid accumulation of S. obliquus . Under normal light conditions, sodium acetate proves to be the most favorable carbon source for the growth and lipid accumulation of S. obliquus . However, under dim light conditions, glucose is verified to be the most effective carbon source for S. obliquus . Additionally, under low light conditions, the final biomass density of S. obliquus is less than half of that in normal light conditions, indicating that light intensity significantly affects algal growth. Furthermore, acclimation to organic carbon enhances the vitality of S. obliquus and its pollutant removal capacity. The investigation into the role of organic carbon in lipid production and wastewater treatment by S. obliquus not only advances the theoretical research of microalgal biotechnology but also holds significant environmental and economic value. This provides a broader development perspective for future applications in the fields of water treatment and green energy.