Kinetics Evaluation of Total Solids Content Affects on Biohydrogen Production from Food Waste by Dark Fermentation

The impact of starting total solids content on biohydrogen production from food waste by dark fermentation was examined in the present study. Batch experiment was taken into account with different TS level between 10–50 g/L under the starting pH of 5.5. The optimum concentration of solids was identified to lie between 10–30 g/L, with the peak biohydrogen yield and production rate of 90.7 mL/g TS<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">added</inf> and 15.7 mL/g VS-h attained at TS concentration of 30 g/L. Adverse conditions that have the potential to profoundly influence the prolonged stability of the system include a final pH reading beneath 4.18, increased levels of propionic acid accumulation, and a reduction in the rate of TS solubilization, which was perceived at TS concentrations of 40 g/L and higher. The Gompertz model was employed to describe the kinetics of biohydrogen production. The maximum hydrogen yield (H<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</inf>), maximum production rate (R<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">max</inf>), and lag phase duration were gained to be 10.17 mL H<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>, 56.02 mL H<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>/day, and 12.2 hours, respectively. These results were obtained at a total solids (TS) level of 30 g/L.