INFLUENCE OF PHENOL ADDITIONS ON THE EFFICIENCY OF AN ANAEROBIC HYBRID DIGESTER TREATING LANDFILL LEACHATE

A hybrid digester with leachate as substrate was used to determine the influence of the addition of phenol. The phenol was increased stepwise from 2 to 25 mg/l and then to 30, 40, 50 and 60 mg/l leachate. Within 24 h the addition caused a significant decrease in the COD removal and biogas production while the methane content increased. Phenol loading was characterised by the accumulation of volatile fatty acids. With the continuous addition of phenol, a recovery time of 28 d was required for the performance to reach the control values. As the concentration was increased, the recovery time shortened to 8 d at 20 mg/l. At higher concentrations (> 50 mg/l) the recovery time was found to increase to > 60 d.