Inhibition effect of zinc, cadmium, and nickel ions in microalgal growth and nutrient uptake from water: An experimental approach

The effect of heavy metals (Cd, Ni, and Zn) on the growth of Chlorella vulgaris and nutrient uptake was assessed. C. vulgaris was cultivated in a synthetic solution with a single or ternary metal system. Biomass growth was well predicted considering a competitive inhibition model. The higher specific growth rate (0.34 d(-1)), biomass productivity (98.1 mg . L-1 . d(-1)), heavy metals uptake efficiency (85%) was obtained for the cultures with Cd and Zn ions. The higher nutrient removal was observed in the presence of Cd ions (91% nitrogen and 99% phosphorus). The highest inhibition on biomass growth (> 88%) was observed in the presence of nickel ions. In the ternary system, microalgae growth inhibition was similar to that observed in the presence of only nickel ions. Although, wastewaters containing nutrients and residual concentrations of zinc and cadmium ions can be used for C. vulgaris production, in the presence of residual concentrations of nickel ions, biomass growth is negligible.