Isolation of a bacterial strain, Acinetobacter sp. from centrate wastewater and study of its cooperation with algae in nutrients removal

•Algae were able to grow healthy on bacteria-containing centrate wastewater.•A strain of beneficial aerobic bacteria, Acinetobacter sp., was isolated.•Co-cultivation of algae and bacteria improved the nutrient removal efficiencies.•Synergistic cooperation was observed in the growth of algae and Acinetobacter sp.

Algae were able to grow healthy on bacteria-containing centrate wastewater in a pilot-scale bioreactor. The batch experiment indicated that the co-cultivation of algae and wastewater-borne bacteria improved the removal efficiencies of chemical oxygen demand and total phosphorus in centrate wastewater to 93.01% and 98.78%, respectively. A strain of beneficial aerobic bacteria, Acinetobacter sp., was isolated and its biochemical characteristics were explored. Synergistic cooperation was observed in the growth of algae and Acinetobacter sp. Removal efficiencies of some nutrients were improved significantly by the co-cultivation of algae and Acinetobacter sp. After treatment, residual nutrients in centrate wastewater reached the permissible discharge limit. The cooperation between algae and Acinetobacter sp. was in part attributed to the exchange of carbon dioxide and oxygen between the algae and bacteria. This synergetic relationship between algae and Acinetobacter sp. provided a promising way to treat the wastewater by improving the nutrients removal and biomass production.