Fractal Characteristics and Scale Dependence of Mature Granular Sludge in Anaerobic Baffled Reactor (ABR)
ABR成熟颗粒污泥的分形特征与尺度效应

Based on the SEM-images of mature granular sludge in ABR, the research process on fractal characteristics of these granules was built. The treatment and fractal dimensions calculation of the images were carried on through Photoshop, Newscan and Fips programs. The results showed that the boxing-counting dimensions of the mature granular sludge were more than 1.85, and the granules formed in the third and fifth compartments were more compact. The boundaries of the same granular sludge were fractal with the fractal dimensions of approximate 1.10, demonstrating the irregularity of the boundaries or surfaces, furthermore the surface of these granules formed in the first and fifth compartments was more irregular. It seemed that the compass dimensions of the granules boundary were a proof of irregularity of their surface. Moreover, there existed two scale scopes in calculating the compass dimensions of each granule, especially some of them with a range of one order of magnitude. A little discrepancy was appeared between box-counting and compass ways to calculating fractal dimensions. It will be important to build relationship between fractal dimensions with different scales and composition, structure, physico-chemical characteristics of granular sludge.