A COMPARATIVE-STUDY OF THE PHYSICAL CHARACTERISTICS OF ANAEROBIC GRANULAR SLUDGES

Physical and chemical characteristics of granular sludges from a range of industrial upflow sludge blanket reactors were examined as part of a study into granule structure and stability. The strength of the granules was measured in terms of the turbidity produced by sonication. The charge on the particles which had been released was also measured. In addition, extracellular polymers were extracted from the granules and their carbohydrate and protein content measured. The results showed that the granules had a wide range of strengths and that, in a single reactor, granules sampled from the bottom were not as strong as those obtained from higher points. Taken overall, the data suggest that granule structure depends on the composition of the extracellular polymers and the presence of inorganic molecules in the feedstock.