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

Abstract

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 (CODCr), 91.3 and 92.% for NH3─ N (ammoniacal nitrogen), and 9.6 and 84.6% for PO43−─ 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), 2 days solid retention time (SRT), 6 h per cycle, 3, mg L−1 mixed liquid volatile suspended solid (MLVSS), and 8 L d−1 treatment amount per day (Q). The system has an average CODCr removal efficiency of 79.8%, a NH3─ N removal efficiency of 91.5%, and a PO43−─ P removal efficiency of 76.5% in 3.5% saline synthetic wastewater including 4 mg CODCr L−1, 1 mg NH3─ N L−1, and 5 mg PO43−─ P 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.