Effect of o-chlorophenol concentration on biomass during sulfate-reduction dechlorination in two different systems

The effect of increasing the concentration of o-chlorophenol (2-Chlorophenol, 2-CP) was evaluated on a sulfate-reducing consortium in a fluidized fixed biofilm reactor (FFB) and a upflow sludge blanket reactor (SB), this process was evaluated and compared in both reactors. The FFB continuous reactor was fed with formic acid as an inducer at a COD/SO4-2 of 0.76 with 2-CP concentrations of 0.19, 0.27 and 0.39 mmol/L, achieving a maximum degradation of 39% of 2-CP at 0.19 mmol/L. The degradation capacity of 2-CP in the bioreactor decreased as the concentration of the toxic compound increased, and a proportional diminution of sulfate consumption was observed. On the other hand, an SB reactor was fed under similar conditions and using the same 2-CP concentrations for comparison. In this case, a maximum degradation of 51% of the 2-CP was observed at 0.19 mmol/L. Sulfate consumption followed the same pattern as in the FFB reactor. This study suggests that biomass adaptation under sulfate-reduction conditions could be used to obtain microorganism adapted to 2-CP and probably chlorophenolic compounds in reactors.