Anaerobic Digestion of Food Waste in A Horizontal Plug Flow Reactor

Abstract

Food waste is the single largest component of the waste stream by weight These organic newlinewastes needs to be managed in a sustainable way to avoid depletion of natural resources newlineminimise risk to human health reduce environmental burdens and maintain an overall newlinebalance in the ecosystem Anaerobic digestion is a promising technology which could newlineeffectively address the problem of food waste disposal yielding valuable outputs like biogas newlineand fertilizers The main focus of this research work was to evaluate and optimize the newlinemethane potential of food wastes and to have a process for sustainable energy production for newlinesmall communities Our institute is a residential campus with two cafeterias catering to 2500 newlinestudents per day and generating one ton of food waste per day Four different categories of newlinefood waste collected from the institutes mess were studied cooked vegetables CV cooked newlinedals CD cooked rice CR and a mixture of these food wastes MFW Biochemical newlinecharacterization of the waste fractions was carried out and linked to their anaerobic newlinebiodegradation The biogas and methane yield of food waste was evaluated using newlinebiochemical methane potential assays and batch anaerobic digestion tests performed at 37oC newlineThe experimental study in batch reactors reveals that all the four wastes degrade to the same newlineextent Mixing different fractions of food wastes was neither detrimental nor synergistic to newlinebiodegradation in anaerobic digestion process newlineThis study was followed by construction of a horizontal plug flow reactor for anaerobic newlinedigestion of food wastes generated in the institutes cafeteria The performance of this reactor newlinewas monitored for approximately two years and microbial community of the anaerobic newlinedigester was studied by terminal restriction fragment length polymorphism The parameters newlinemonitored during the study were pH solid content chemical oxygen demand and biogas newlineproduction Methanoculleus sp was found to be the dominant in all samplings done newlineindicating hydrogenotrophic pathway of methanogenesis Diversity indices like Shannon.