Consumption of 2-chlorophenol using anaerobic sludge: physiological and kinetic analysis

Chlorophenols are toxic and recalcitrant compounds produced by many industrial. Different strategies have been used to improve their biological consumption, but there is insufficient information to understand how the process is carried out. The objective of this study was to evaluate in batch tests the effect of the addition of phenol, acetate, or glucose as electron donors at different concentrations on the efficiencies, yields, and specific rates of 2-chlorophenol (2-CP) consumption. The addition of phenol (177.6 mg C/L), acetate (127.6 mg C/L), or glucose (77.6 mg C/L) increased the 2-CP consumption efficiency up to 54.6, 98.6, and 97.8 %, respectively. With respect to the control assay without electron donor, the specific rate of 2-CP consumption was up to 2.5 times higher with phenol (177.6 mg C/L), 8.4 times higher with acetate (127.6 mg C/L), and 3 times higher with glucose (127.6 mg C/L). The results showed that the type and concentration of electron donor determine the physiological behavior of the anaerobic sludge, modifying efficiency, yield, and specific rate values of the 2-CP consumption process. The addition of readily oxidable cosubstrates seems to be a good alternative and might be used for the biological treatment of industrial wastewater polluted with chlorinated phenols.