Influence of Di-n-butyl phthalate (DnBP) on the Characteristics of Anaerobic Granular Sludge in an IC Reactor

Y. W. Ma, M. Huang, J. Wan and Y. M. Chen

Abstract
The characteristics of anaerobic granular sludge in the internal circulation (IC) anaerobic reactor and influence of particles by Di-n-butyl phthalate (DnBP) at normal temperature were conducted. The results show that, with HRT decreasing, the percentage of granular particles smaller than 0.3 millimeters and in the range of 2.0 and 3.0 millimeters had decreased while those between 0.9 and 2.0 mm increased significantly. For the extracellular polymeric substances (EPS), the protein content increased more, and the polysaccharide content had no significant changes; SS and VSS appeared to decline after an initial ascent; Specific methanogenic activity (SMA) of granular sludge firstly reduced significantly, and then gradually stabilized. At toxicity and recovery experiment, SMA and content of coenzyme both reduced sharply with the DnBP concentration increasing. When the concentration of DnBP was higher than 1.2 g L–1, the SMA and content of coenzyme F420 virtually reached zero. Regardless of changes in the activity of the sludge, the tendency of SMA was consistent with coenzyme F420. Therefore, DnBP had an inhibiting effect on the anaerobic granular sludge.

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Keywords
internal circulation anaerobic reactors, anaerobic granular sludge, granular diameter, setting velocity, specific methanogenic activity, content of coenzyme F420