| Navipol Yellow GR is an organic solvent azo dye manufactured by Sunbelt Corp. in Rock Hill, SC. The effluent generated from the manufacturing of this dye is highly colored, toxic, and contains trace solvents consisting of mixed xylene isomers and ethyl benzene. Traditional wastewater treatment systems are unable to remove the color and toxicity from the effluent. This study investigated using a sequential anaerobic / aerobic treatment system to decrease color and toxicity of the dye effluent. The anaerobic phase used bacteria cultures of Pseudomonas aeruginosa, Bacillus subtilis, Enterococcus faecalis, or Enterobacter aerogenes to decrease the color of the dye. The toxicity was decreased through aerobic treatment using Rhodococcus rodocorous or Escherichia coli . The results showed that color was decreased by an average of 47.5% after 24 hrs of anaerobic treatment. There was no significant difference among the four anaerobic bacteria tested. Toxicity was measured using Abratox bioluminescent toxicity assay. Toxicity was reduced significantly after 48 hrs of aerobic treatment. The greatest toxicity reduction came from samples containing R. rodocorous as compared to those containing E. coli. |
