Assessing textile wastewater treatment in an anoxic-aerobic photobioreactor and the potential of the treated water for irrigation

Abstract

The potential of an anoxic-aerobic photobioreactor for the treatment of synthetic textile wastewater (STWW) was evaluated in terms of carbon and nutrient removal, water and toxicity reduction. The potential of the treated water for irrigation of Raphanus sativus was also assessed. Despite the low C/N ratio of the STWW, microalgae-bacteria symbiosis supported steady-state removal efficiencies of total organic carbon, total nitrogen and total phosphorus of 48±3%, 87±11% and 57±5%, respectively, at a hydraulic retention time of 10days. In addition, a consistent decolorization of the STWW was observed, with disperse orange-3 and blue-1 removals of ~80% and ~75%, respectively. This effective STWW treatment was confirmed by the reduction in genotoxicity potential and enhanced growth of R. sativus during irrigation with treated water. Finally, the heavy metal content of the soils irrigated with treated water was lower than that of STWW irrigated soils, which highlights the potential of this anoxic-aerobic photobioreactor for the treatment of textile wastewater and water reuse. However, more studies are still needed to elucidate the long-term effects of the treated water over the final consumer health.