Decolorization and phytotoxicity reduction in an innovative anaerobic/aerobic photobioreactor treating textile wastewater

The potential of a novel anaerobic/aerobic algal-bacterial photobioreactor for the treatment of synthetic textile wastewater (STWW) was here assessed. Algal-bacterial symbiosis supported total organic carbon, nitrogen and phosphorous removal efficiencies of 78 ± 2%, 47 ± 2% and 26 ± 2%, respectively, at a hydraulic retention time (HRT) of 8 days. A decrease in the HRT from 8 to 4 and 2 days resulted in a slight decrease in organic carbon and phosphate removal, but a sharp decrease in nitrogen removal. Moreover, an efficient decolorization of 99 ± 1% and 96 ± 3% for disperse orange-3 and of disperse blue-1, respectively, was recorded. The effective STWW treatment supported by the anaerobic/aerobic algal-bacterial photobioreactor was confirmed by the reduction in wastewater toxicity towards Raphanus sativus seed germination and growth. These results highlighted the potential of this innovative algal-bacterial photobioreactor configuration for the treatment of textile wastewater and water reuse. [Display omitted] •An effective organic matter removal occurred in the anaerobic reactor.•The CO2 produced in the anaerobic reactor was photosynthetically consumed.•The anaerobic/aerobic photobioreactor supported an effective color removal.•Toxicity reduction was confirmed by R. sativus seed germination.•Irrigation with treated water enhanced plant growth compared to fresh water.