Phycoremediation of wastewater using algal-bacterial photobioreactor: Effect of nutrient load and light intensity

Abstract

The current study demonstrates the nutrient removal efficiency of algal-bacterial photobioreactors in the semi-batch mode for secondary treated domestic wastewater. The experiments were conducted to predict the optimum conditions for running a photobioreactor at a comparatively larger scale. The main focus was on optimizing illumination costs and nutrient removal efficiency to make reactor construction and operation economically viable. Chlorella vulgaris and Chlamydomonas reinhardtii were used for the experiments. Various input parameters were varied, and nutrient removal efficiencies along with biomass, chlorophyll-a content, temperature, pH, alkalinity, dissolved organic carbon, and dissolved oxygen were monitored. Model simulations were also run to confirm optimum performance. A maximum of ~25 mg l−1 N and ~10 mg l−1 P were found to be efficiently removed within 2 days hydraulic retention time (HRT), 9 h:3 h light: dark condition and 1543 μmol photons m2 s−1 light intensity. The results demonstrate superior nutrient removal efficiency than similar to previous studies.