The treatment of textile wastewater including chromium(VI) and reactive dye by sulfate-reducing bacterial enrichment.
Sulfate-reducing bacteria (SRB) that could grow on modified Postgate C medium (PC) containing chromium(VI) were isolated from industrial wastewaters and their chromium(VI) reduction capacities were investigated as a function of changes in the initial pH values, chromium, sulfate, NaCl and reactive dye concentrations. The optimum pH value at 50 mg l(-1) initial chromium(VI) concentration was determined to be 8. Chromium(VI) reduction by SRB was investigated at 22.7-98.4 mg l(-1) initial chromium(VI) concentrations. At the end of the experiments, the mixed cultures of SRB were found to reduce within 2-6 days more than 99% of the initial chromium(VI) levels, which ranged from 22.7 to 74.9 mg l(-1). The effects of the initial 0-9.0 g l(-1) concentrations of disodium sulfate and 0-6% (w/v) concentrations of NaCI to chromium reduction showed that the lowest concentrations of sulfate and NaCI were the best for chromium reduction in the PC medium including 50 mg l(-1) chromium(VI). Chromium(VI) reduction in 50 mg l(-1) and 25-100 mg l(-1) Remazol Blue, Reactive Black B or Reactive Red RB containing media were also investigated. In the experiments, 25-30% of the initial dye concentrations and 95% of the chromium(VI) was removed from the medium at the end of 72-h and 24-h incubation periods, respectively.
Cetin
Demet
D
Department of Biology, Faculty of Science, Ankara University, 06100 Beşevler, Ankara, Turkey.
Dönmez
Sedat
S
Dönmez
Gönül
G
D001419:Bacteria / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002857:Chromium / Q000737:chemistry / Q000378:metabolism*; D004396:Coloring Agents / Q000737:chemistry / Q000378:metabolism*; D007220:Industrial Waste / Q000032:analysis; D015394:Molecular Structure; D013783:Textile Industry; D013997:Time Factors; D014865:Waste Disposal, Fluid / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D014877:Water Pollution, Chemical / Q000517:prevention & control
D004396:Coloring Agents; D007220:Industrial Waste; D014874:Water Pollutants, Chemical; D002857:Chromium