Surface characteristics of acidogenic sludge in H2-producing process

Abstract

The surface characteristics, including rheological, fractal characteristics, hydrophobicity as well as surface free energy, of H 2 -producing sludge in acidogenic fermentative process were investigated in this study. Both rheological and fractal characteristics of the H 2 -producing sludge changed slightly in the acidogenesis. The sludge fractal dimension was larger than those of other microbial aggregates, whereas the affinity of the microbial cells for the hydrocarbon had a peak value in the fermentation process. Both specific H 2 and volatile fatty acids/ethanol production rates of the sludge had a peak of 108 mL-and 480 mg L -1 h -1 g-VSS -1 . There was a relationship between the hydrophobicity of the H 2 -producing sludge and its specific H 2 -producing activity. The surface free energy of the H 2 -producing microorganisms had a lowest value in their growth process.

Rheological characterisation of thermally-treated anaerobic digested sludge: Impact of temperature and thermal history

“…Effect of temperature and thermal history on the rheological behaviour of digested sludge Fig.2a shows that sludge becomes less viscous as the temperature increases which is consistent with the literature (Sozanski et al 1997, Mu et al 2007, Baudez et al 2013, Battistoni et al 1993b). Fig.2b highlights the effect of thermal history on sludge flow curve at 20°C.…”

“…A temperature-dependence of sludge rheological characteristics has been reported by several authors (Sozanski et al 1997, Battistoni et al 1993a, Mu et al 2007, Abu-Jdayil et al 2010, Baudez et al 2013, Baroutian et al 2013). An Arrhenius-like model is widely used to describe the relationship between temperature and rheological parameters (Baudez et al 2011, Battistoni et al 1993a, Mu et al 2007, Pevere et al 2009. However, in a recent paper, Baudez et al (2013) objected these results.…”