Comparing the Effect of Total Solids Concentration on Bio-Hydrogen Production Potential of Food Waste and Its Derivatives Under Mesophilic Thermophilic Conditions

Abstract

The effect of three total solid (TS) concentrations of 7.5, 10 and 12.5% on bio-hydrogen production potential of food waste (FW) in comparison with noodle waste (NW) and rice waste (RW) derived from FW were studied after co-digesting the wastes with heat shocked sludge under mesophilic (37°C) and thermophilic (55°C) conditions. The increase in TS concentration from 7.5% to 10% found an effective way to improve cumulative bio-hydrogen production from all tested wastes. As a whole, 7.5% TS concentration represented higher conversion efficiency of volatile solids into bio-hydrogen and the highest experimental yield of 95.8mL/VS fed was observed in 7.5%NW digester under thermophilic conditions. The increase in temperature within experimental range found an effective way to increase bio-hydrogen production potential of FW and NW only, whereas the same increase in temperature caused negative impact on bio-hydrogen production potential of RW. The optimum time period for active bio-hydrogen production found to be 24-72h of incubation. After 72h of incubation, the bio-hydrogen production reduced considerably in all reactors due to an abrupt increase in volatile fatty acid, and due to inhibition of bio-hydrogen production the drop in pH was also decreased.

Optimization of Subcritical Water Pretreatment on Glutinous Rice Husk for Efficient Sugar and Hydrogen Production

“…The optimum pH value used in this dark fermentation was 5.5. Considering these facts, Arslan et al [83] determined that the ideal pH range for biohydrogen synthesis was between pH 4.5 and 8.5. Lowering the process pH below 4, can impact metabolic pathways, which can prevent bacteria that produce biohydrogen from working [84].…”

“…The selective concentration of total solid for the anaerobic digestion was 10%. Arslan et al [83] stated that most anaerobic digestion-based biohydrogen production occurred in liquidstate environments with TS concentrations below 15%. Due to osmotic stress and excessive metabolite accumulation, which ultimately leads to microbial inhabitation, increasing the TS concentration will reduce the reactor size and diminish bio-hydrogen production [85].…”