Urban wastewater treatment by microalgae, bacteria and microalgae–bacteria system (Laboratory-scale study).

Besides existing methods of urban wastewater treatment processing (WWTP), microalgae culture systems are one of the environmental friendly methods for improving urban wastewater treatment. In this research, the removal efficiency of N-nitrate and orthophosphate from urban wastewater were investigated using free and immobilized Chlorella vulgaris microalgae, Pseudomonas fluorescens bacteria and symbiosis of microalgae with bacteria. Pseudomonas fluorescens bacteria are a group of bacteria that stimulates plant growth. The performance of immobilized microalgae and immobilized bacteria in nitrate removal was better than that in free microalgae and free bacteria. The results showed that the maximum removal efficiency of N-NO3 was 87.06% in immobilized microalgae (MIM). In removing orthophosphate, free microalgae-bacteria (MBFr) and immobilized microalgae—bacteria (MBIm) had higher performance among other treatments with removal efficiency of 89.64% and 86.38%, respectively. According to significant reductions of orthophosphate on the second day of measurements, the residence time could be considered about two days. [ABSTRACT FROM AUTHOR]