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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/VSfed 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. [ABSTRACT FROM AUTHOR]

were tested for bio-hydrogen production by using sludge as a source of mix consortia of Clostridium under different physical conditions (pH 5, 6, and 7; temperature 37 °C and 55°C). The increase in pH increased the bio-hydrogen yield for all tested wastes, whereas an increase in temperature increased the bio-hydrogen yield just for food waste. The highest experimental yield of 115.76 ml/VSremoved was produced in the mesophilic noodle waste reactor at pH 7. The drop in pH from 7 to 4.860.2 was found optimum for bio-hydrogen production for all tested wastes under mesophilic as well as thermophilic conditions. Most of the hydrogen production was observed within 72 h of incubation, which can be used as the optimum biohydrogen production period for food waste. The bio-hydrogen yield, final volatile fatty acids (VFA), and glucose consumption at 72 h were analyzed with the help of the response surface methodology. The resultant plots represented an increase in glucose consumption with the increase in pH from 5 till pH 660.5, after which glucose consumption started to decrease up to pH 7. The final VFA represented a similar trend as that observed for glucose except that the change in VFA production was observed due to the temperature and transition was observed at 47.561.5 °C for food waste as well as for noodle waste. [ABSTRACT FROM AUTHOR]