Evaluating emerging pollutant removal in a scale-down high rate algae pond

Abstract

Efficient wastewater treatment processes should provide removal of contaminants of emerging concern at low operational and installation costs. Microalgae based systems are one of the most promising low cost technologies. However, the strong impact of environmental conditions, that impact the performance, have limited the implementation in urban wastewater treatment and the capacity of pollutant removal has been documented under wide range of conditions (lab scale and outdoor). This study evaluates the use of microalgae cultures for the removal of contaminants of emerging concern using a scale-down system that reproduce outdoor conditions (light and mass transfer). Antimicrobials and anti-inflammatory drugs were efficiently removed, while preservatives, hormones, lipid regulators and other chemicals presented moderate or low eliminations. Antibiotics, except of tiamulin, were poorly removed. Biosorption into algal-bacterial biomass played an important role in pollutant removal. Light mediated breakdown was limited to pollutants sensitive to visible light since no UV radiation was used. The capacity of algae ponds for the removal of several of the contaminants present in sewage was demonstrated in spite of the changes in the microbial populations due to the seasonality.