Effect of substrate feeding on viscosity evolution of anaerobic granular sludges

This work aims to describe the effect of the feeding regime of anaerobic activity tests on the limit viscosity (mu(lim)) evolution of the granules. Batch experiments were performed with 3 different sources of substrate: acetate, peptone, and glucose. Despite, the substrate origin was shown to affect the mu(lim) evolution of granules, no clear relationship was found between the mu(lim) evolution, type of substrate and other granule physico-chemical characteristics (i.e. pH; % of Volatile Suspended Solid; concentration of exopolymeric substances, divalent cations, P and S). The origin of granules and the substrate feeding regime modify the surface shape of the granules and may change granule-granule interactions under a shear stress, thus affecting the evolution of the mu(lim) value during long term reactor operation.