Development of Image Analysis Techniques as a Tool to Detect and Quantify Morphological Changes in Anaerobic Sludge: II. Application to a Granule Deterioration Process Triggered by Contact With Oleic Acid

Abstract: Image analysis techniques are applied to monitor the morphological changes in granular sludge present in an expanded granular sludge blanket (EGSB) reactor fed with oleic acid. Deterioration of granular sludge was monitored along the trial period by measuring the percentage of ag-gregates smaller than 1 mm (in terms of Feret diameter) either in terms of projected area or in terms of number of aggregates. A good correlation was obtained between these values and the percentage of aggregates smaller than 1 mm were physically sorted and quantified by the volatile suspended solid content. The ratio of total fil-aments length to cross-sectional area of aggregates de-fined as LfA, was applied to quantify the dispersion level of the granular sludge, which increased until day 141 and remained almost invariant afterwards. LfAwas sensitive t