Effect of the initial total solids concentration and initial pH on the bio-hydrogen production from cafeteria food waste

In this paper, the influence of the initial pH and the total solids (TS) concentration on hydrogen production from the organic fraction of cafeteria food waste at mesophilic conditions in batch reactors was determined. It was found that the yield and specific hydrogen production rate were influenced by the initial pH and the initial total solids concentration. The highest hydrogen production rate, 2.90 mmolH2/d, was obtained at 90 gTS/L and a pH of 5.5. Under this condition, the TS and chemical oxygen demand (COD) removal were the lowest (10% as TS and 14% as COD). However, considering the specific values, the highest specific degradation rate (192.2 mLH2/gVSremoved/d) was obtained with the lowest TS concentration and an initial pH of 7.0. It was found that the influence of the TS concentration on hydrogen production was more significant than that of the initial pH for this type of residues.

► Hydrogen production was conditioned by the initial total solid concentration and pH.
► Initial TS concentration was more significant than the initial pH on the SHP.
► Highest SHP were obtained at the highest TS concentration.
► Highest TS and COD removal were observed at low TS concentration.