Treatment of hypersaline wastewater in the sequencing batch reactor

Hypersaline wastes are generated during industrial activities that include chemical manufacturing, oil and gas production and waste minimization practices. These wastes which contain organic compounds and high concentrations of salt (>3.5%), are difficult to treat using conventional microorganisms typically found in wastewater facilities. Biological treatment to remove organics without dilution will require the use of halophilic organisms which have special adaptations for survival at high salinities. In this paper, studies were conducted with a moderate halophile isolated from the Great Salt Lake, Utah, U.S.A. The organism was able to degrade phenol in a simulated oil field produced water containing 15% salt if iron, nitrogen and phosphorus were added to the medium. This organism was used to develop a halophilic sludge in a Sequencing Batch Reactor (SBR) operated at 15% salt during a 7 month study period. An average phenol removal of over 99.5% was achieved with this reactor and specific substrate removal rates were similar to those reported for more conventional treatment cultures.