Treatment of Saline Wastewater Containing a High Concentration of Salt Using Marine Bacteria and Aerobic Granule Sludge

This study develops an ecofriendly and inexpensive biological treatment for high-salinity wastewater. The marine bacteria Bacillus sp. KGN1 and Vibrio sp. KGP1 show removal efficiencies of 75.3 and 65.4% for chemical oxygen demand by the dichromate method (${\mathrm{COD}}_{\mathrm{Cr}}$), 91.3 and 92.0% for ${\mathrm{NH}}_3─\mathrm{N}$ (ammoniacal nitrogen), and 90.6 and 84.6% for ${\mathrm{PO}}_4^{3-}─\mathrm{P}$ (phosphate), respectively, during batch mode for 12 h in 3.5% saline artificial wastewater. The lab-scale sequencing batch reactor (SBR) system with marine bacteria–supplemented aerobic granule sludge (AGS) is operated under the following conditions: 12 h hydraulic retention time (HRT), 20 days solid retention time (SRT), 6 h per cycle, $\mathrm{3,000}\mathrm{mg}{\mathrm{L}}^{-1}$ mixed liquid volatile suspended solid (MLVSS), and $80\mathrm{L}{\mathrm{d}}^{-1}$ treatment amount per day (Q). The system has an average ${\mathrm{COD}}_{\mathrm{Cr}}$ removal efficiency of 79.8%, a ${\mathrm{NH}}_3─\mathrm{N}$ removal efficiency of 91.5%, and a ${\mathrm{PO}}_4^{3-}─\mathrm{P}$ removal efficiency of 76.5% in 3.5% saline synthetic wastewater including 400 mg ${\mathrm{COD}}_{\mathrm{Cr}}$ ${\mathrm{L}}^{-1}$, 10 mg ${\mathrm{NH}}_3─\mathrm{N}$ ${\mathrm{L}}^{-1}$, and 5 mg ${\mathrm{PO}}_4^{3-}─\mathrm{P}$ ${\mathrm{L}}^{-1}$. The results indicate that the SBR biological system with AGS supplemented with high-efficiency marine bacteria is effective for treating saline wastewater containing a high concentration of salt.