Bio-hydrogen production from food waste through anaerobic fermentation

In order to protect our planet and ourselves from the adverse effects of excessive CO2 emissions, and to prevent an imminent non-renewable fossil fuel shortage and energy crisis, there is the need to transform our current “fossil fuel dependent” energy systems to new, clean, renewable energy sources. The world has recognized hydrogen as an energy carrier that complies with all the environmental quality, energy security, and economic competition demands. This research aims at producing hydrogen through anaerobic fermentation, using food waste as the substrate. Four food waste substrates were used: rice, fish, vegetable, and mixed. Bio-hydrogen production was performed in lab scale reactors, using 250 mL serum bottles. The food waste was first mixed with the anaerobic sewage sludge and incubated at 37°C for 31 days (acclimatization). The anaerobic sewage sludge was then heat treated at 80°C for 15 minutes. The experiment was conducted at an initial pH of 5.5 and temperatures of 27°C, 35°C, and 55°C. The maximum cumulative hydrogen produced by rice, fish, vegetable and mixed food waste substrates were highest at 37⁰C (Rice =26.97 ± 0.76 mL, fish = 89.70 ± 1.25 mL, vegetable = 42.00±1.76 mL, mixed = 108.90±1.42 mL). A comparative study of acclimatized (the different food waste substrates were mixed with anaerobic sewage sludge and incubated at 37°C for 31days) and non-acclimatized food waste substrate (Food waste that was not incubated with anaerobic sewage sludge) revealed that acclimatized food waste substrate enhanced bio-hydrogen production by 90% - 100%. This was further verified using a statistical test at (P < 0.001).