Biological treatment of hypersaline wastewater by a biofilm of halophilic bacteria

Abstract

ABSTRACT: Each year, billions of gallons of wastewaters containing high concentrations of salt (>3.5% w/v) and waste organics are generated by industry. Biological treatment of these hypersaline waste brines to remove organics could reduce the environmental impact and cost of waste disposal. Unfortunately, the salinity of many waste brines makes them difficult to treat with conventional waste treatment cultures. This paper demonstrates that heterotrophic, halophilic organisms can be used to remove phenol from a synthetic waste brine containing 15% salt. The reactor system used in this study was a novel periodically operated biofilm reactor, the Sequencing Batch Biofilm Reactor (SBBR). The SBBR uses permeable silicone tubing to supply oxygen to the reactor. A biofilm of halophiles isolated from the Great Salt Lake, Utah, ecosystem readily developed on the tubing surface and degraded waste organics. The experimental results presented herein demonstrate that the SBBR can produce a stable, high‐quality effluent despite fluctuations in influent phenol concentration. The results of periodic track studies illustrate that biomass accumulation increases oxygen demand but does not significantly improve overall reactor performance