Enhanced phosphorus removal from wastewater by growing deep-sea bacterium combined with basic oxygen furnace slag

• Bio-BOFS showed a better performance of P removal than unitary bacterium and BOFS.
• Solution pH of 7.8–8.0 was maintained by bacterium in Bio-BOFS system.
• Bio-BOFS alleviated cementing of BOFS and enlarged the particle size of BOFS.
• More than 90% phosphorus removal rate for salinity water was achieved by Bio-BOFS.

As one solid waste with potential for phosphorus removal, application of slags in water treatment merits attention. But it was inhibited greatly by alkaline solution (pH > 9.5) and cemented clogging generated. To give one solution, phosphorus removal was investigated by combining deep-sea bacterium Alteromonas 522-1 and basic oxygen furnace slag (BOFS). Results showed that by the combination, not only higher phosphorous removal efficiency (>90%) but also neutral solution pH of 7.8–8.0 were achieved at wide ranges of initial solution pH value of 5.0–9.0, phosphorus concentration of 5–30 mg/L, salinity of 0.5–3.5%, and temperature of 15–35 °C. Moreover, sedimentary property was also improved with lower amount of sludge production and alleviated BOFS cementation with increased porosity and enlarged particle size. These results provided a promising strategy for the phosphorus recovery with slags in large-scale wastewater treatment.

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