Biological reduction of acid red 14 by elemental sulfur and methanol-based reactors.

In this study for the first time, biological reduction of the Acid Red 14 in elemental sulfur-based anaerobic reactor was studied. Two up-flow packed bed reactors were investigated in parallel for 95 days. Sulfur and methanol were used as electron donors in these reactors and the performance of the sulfur-based reduction process was investigated in comparison with a conventional electron source - methanol. The reactors were operated in 7 different periods, the influent dye concentration was kept at 5-10 mg/L and HRT was set to 12-24 hours. While influent Acid Red 14 concentration was 10±0.14 mg/L, it was reduced to 1.3±0.2 in the methanol-based reactor and 2.05±0.2 in the sulfur-based reactor. Elemental sulfur was used for the first time in and the effect of sulfur oxidation in dye reduction process on sulfate and alkalinity production was also investigated. [ABSTRACT FROM AUTHOR]