Biodegradation of 2-chlorophenol (2CP) in an anaerobic sequencing batch reactor (ASBR)

摘要

The aim of this study is to contribute to the knowledge about anaerobic digestion of 2-chlorophenol (2CP) in an anaerobic sequencing batch reactor (ASBR). Two reactors were set up (ASBR _A and ASBR _B). The ASBR _A was fed with 2-chlorophenol (28-196 mg 2CP-C/L) and no other exogenous electron donor. The ASBR _B was fed with a mixture of 2CP (28-196 mg 2CP-C/L) and phenol (28-196 mg phenol-C/L) as an electron donor. The process evaluation was conducted by three means: first by substrate consumption efficiency (E _(2CP)), second, by biogas yield (Ybiogas-C/2CP-C) and third, by the specific consumption rates (q _(2CP)) as response variables. The 2CP consumption efficiency (90±0.4%) was not influenced by the increase in the concentrations tested. In both reactors ASBR _A and ASBR _B, both concentration as well as speed increased. Concentration increased from 28 to 114 mg 2CP-C/L. The specific consumption rate (q _(2CP)) values were fivefold higher. However, a decrease of 37% was observed at 140 mg 2CP-C/L and one of 72% at 196 mg 2CP-C/L. The biogas yields (0.80±0.06) remained stable in both reactors. In both reactors the biogas yield decreased to 78±3% at 196 mg 2CP-C/L. We might assume this decrease was due to the accumulation of VFA. Finally, poor sludge settleability was determined only in the SBRB reactor at 140 and 196 mg 2CP-C/L. An increase was observed in both SVI≤ 140± 5 mL/g and over exopolymeric protein ≤120 mg EP/L.