Development of Microalgae-Based Bioremediation Systems for Simultaneous Nutrient Removal and Biomass Production from Municipal Wastewater

Abstract

Municipal wastewater contains significant levels of nutrients such as nitrogen and phosphorus that might lead to eutrophication if released without being treated properly. Traditional wastewater treatments mostly concentrate on the removal of pollutants, while microalgal bioremediation is known to provide both the removal of pollutants and production of biomass simultaneously. This research provides a bioremediation scheme based on Chlorella vulgaris for simultaneous removal and production of biomass from municipal wastewater. This methodological approach involves the characterization of the wastewater, wastewater
pre-treatment, cultivation of microalgal cultures, photobioreactor operations, biomass harvesting, and assessment of treatment efficiency. The cultivation period is considered to be 14 days. The system efficiency is measured by total nitrogen removal efficiency, ammonium nitrogen reduction efficiency, total phosphorus removal efficiency, COD reduction efficiency, biomass concentration, and biomass productivity. The performance data set used here shows that total nitrogen reduction efficiency is 80%, ammonium nitrogen reduction efficiency is 83.93%, total phosphorus reduction efficiency is 85%, and COD reduction efficiency is 70%. The biomass concentration goes up from 0.20 to 1.65 g/L, implying a biomass productivity value of 0.1036 g/L/day. All these data make it possible to get a quantitative criterion for the study of dependence between nutrient removal from wastewater and biomass formation. The approach proposed here will help to develop a new technology of wastewater purification where reduction of pollutants is associated with biomass recovery.