4.2.3. Experimental investigations
Most information on floc size diameter in the literature
concerns activated sludge. Andreadakis [65]; Higgins and
Novak [66]; Biggs et al. [67] found that for well mixed
activated sludge systems the typical range of floc sizes was
between 10 and 70 m. No information was found on size
distribution of thickened biological sludge. To assess the
possible influence of AST on the biosolids size distribution,
an identical sample of 6% DS-thickened sludge was
treated by the different thermal and chemical AST presented
above. The experimental set-up is described in Neyens
et al. [9].