This research contributes to community hygiene and bioenergy production from food waste minimizing ever-increasing costs of energy and waste disposal problems to improve environmental quality, the transformation of food wastes to energy is becoming an environmentally friendly and economically attractive practice, due to a large amount of food sent to landfill across the world.The energy demand is increasing about one third during 2013–2040, presently 88% of this demand is met via fossil fuels which are expected to last only about a century. The generation of hydrogen (H2) and methane (CH4) from renewable resources can be an encouraging way to save fossil fuels. Food Waste (FW) is organic waste collected from numerous sources i.e. cafeterias, restaurants, domestic and commercial kitchens, and food processing plants, according to Food and Agricultural Organization (FAO), approximately 1.3 billion tons of foods are wasted. The accumulation of FW causes a critical problem around the world like a health risk, environmental pollution, and scarcity of dumping land. Nowadays the biogas is becoming one of the energy production resources. Anaerobic digestion (AD) is one of the ideal techniques to treat food waste and produce valuable matters and energy.Currently, a two-stage anaerobic digestion process was more advantageous than a single-stage process because it created an optimum condition for each bacterial group, for example, the optimal pH was 5-6 for H2 production in the first stage and pH 7-8 for CH4 production in the second stage. The recirculation process is effective for two reasons; firstly, renovation hydrogen production bacteria secondly, alleviation the acidity of hydrogen reactor by recirculation which leads to reduced/stopped chemical agent addition for adjusting the pH. The bio-H2 and bio-CH4 production from FW with recirculation system by using different recirculation ratio increased the energy in hydrogen reactor than without recirculation system, furthermore reduce the alkaline addition and operation cost.
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