Wastewater Treatment by the Cyanobacterium Species: Synechococcus elongatus as Biosorption Material for Pb,Cr and Ni Heavy Metals

This research studies the effect of carbon dioxide on microalgae during the biological treatment of wastewater. Synechococcus elongatus was cultivated to eliminate heavy metal pollutants (lead, chromium and nickel) at different concentrations (0.5, 1.0, 2.0, 5.0 and 10.0ppm) under rich-CO₂ environment. 50 ml of microalgae cultural medium were bubbled with 2 liters/ minute of CO₂ gas, three times a week for two weeks. The results demonstrate that the effectiveness of microalgae growth and pollutant removal is directly impacted by CO₂ gas dosages, as quickly and efficiently cell adaption in comparison to control groups. The highest pollutant removal was 100% (during day 10 of cultivation) with the presence of CO₂ and 99.93% (during day 14 of cultivation) without the presence of CO₂ for Pb at 0.5 ppm.