Potential of Novel Halotolerant and Psychrotrophic Strain of Planococcus sp. for Water Treatment

To screen multifunctional bacteria for water treatment, a chemical oxygen demand (COD) degradation and flocculation strain S2A15 was obtained from the offshore sewage outfall at Weihai International Beach. Based on the phylogenetic characteristics, a novel strain was identified as a Planococcus species. Strain S2A15 was determined to have the ability of flocculation and COD degradation. A series of experiments showed that the strain S2A15 could be used for the treatment of four types of wastewater, including domestic wastewater (400 mg/L and 800 mg/L) and high salt domestic wastewater (400 mg/L and 800 mg/L). Among them, the best effect was exerted by the strain that reduced by 76.9% in domestic wastewater with 400 mg/L COD. The flocculation ratio reached 60.19%. The optimal treatment conditions are also discussed. We confirmed that the strain S2A15 had salt tolerance and low temperature resistance. The best growth of S2A15 at salt concentration of 6% and further confirmed that the strain could degrade COD at a low temperature.