Rheological properties of anaerobic hydrogen-producing flocs

The rheological characteristics of anaerobic hydrogen-producing flocs were investigated in this study. The Sisko model was employed to describe the rheology of hydrogen-producing flocs and determine their limiting viscosity. In addition, the effects of sludge concentration, temperature, and pH on the floc limiting viscosity were evaluated. Experimental results indicated that the hydrogen-producing flocs showed shear-thinning behavior. The Sisko model was found to be able to adequately describe the rheology of the hydrogen-producing flocs. The relationships between the limiting viscosity of the flocs with the solids content and the limiting viscosity with temperature could be, respectively, modeled by an exponential equation and Arrhenius equation very well. The limiting viscosity of the flocs seemed not to be sensitive to changes of solution pH.