The influence of sodium on biohydrogen production from food waste by anaerobic fermentation

Anaerobic fermentation of food waste for hydrogen production was performed in serum bottles with various linear alkylbenzene sulfonate (LAS) dosages (7.1-21.4 g/l) and sodium concentrations (5.03-28.7 g/l). LAS can effectively inhibit the activity of hydrogen-consuming bacteria, and the maximum hydrogen yield of 109.2 ml/g volatile solid (VS) was obtained at an LAS dosage of 14.3 g/l without added sodium. The feasible pH for hydrogen production is 5.0-6.0, and the process will slow down or stop when the pH is below 5.0.The hydrogen production potential increased when the sodium concentration increased in the range 5.03-14.41 g/l. The maximum hydrogen yield was 154.8 ml/g VS, and then the hydrogen production began to decrease when the sodium concentration increased further. A sodium chloride concentration of 20 g/l and higher will enhance the osmotic pressure and make bacteria inert. In the effluent, acetic acid is the major by-product. The results indicated that the hydrogen production from the anaerobic fermentation of food waste could clearly be increased with the additives and a sodium concentration less than 20 g/l.