Evaluating the effect of initial pH on the growth and treatment of nitrogen compounds in domestic wastewater of Chlorella vulgaris CNK microalgae strain

Abstract

Cultivation of microalgae in the domestic wastewater is an alternative approach over conventional activated sludge processes for simultaneous pollutants removal and byproducts production from the obtained microalgal biomass. This study aims to evaluate the effect of initial pH on the growth and removal efficiency of nitrogen in domestic wastewater of Chlorella vulgaris CNK microalgae strain at laboratory scale. The experiment was completely randomized with four treatments and three replicates with initial pH of wastewater at 6; 7; 8; 9. Purebred of C. vulgaris CNK strain were cultured with BG11 suspension before using for the experiment. Experiment was set up with domestic wastewater (50%), aeration rate of 1.2 L / L / min for 8 hours, culture temperature 20^oC, light intensity 5000 lux. Water samples were collected and analyzed for algae growth and water quality parameters (i.e. N - NH₄⁺, N- NO₃^- and N-NO₂^-) on day 12 of the experiment. Results found that the treatment with initial pH 7 showed the significant growth of C. vulgaris CNK as well as highest efficiency in N-NH₄⁺ removal (54%).