Biomethanationof vegetable waste

Energy crisis is considered to be one of the greatest problems faced by mankind. During the last decade the prices of fossil fuels like oil, coal has risen sharply and there is a continuous depletion of these scarce resources. Hence there is an urgent need to develop and exploit other alternative sources of energy. In this study, biomethanation of vegetable waste with water hyacinth and cow dung was carried out. The experiments were carried out in two reactors and the batch digestion of vegetable waste slurry with water hyacinth was carried out in the laboratory using 2L capacity bottle reactors at ambient temperature conditions (35°C-40°C) and the biogas yield from the reactor over the digestion time was observed. The raw materials used in the study were vegetable waste slurry, seed (cow dung) and water hyacinth. The sample was tested for total solids, volatile solids, total dissolved solids, COD and Carbon Hydrogen and Nitrogen (C:H:N) ratio. The substrate was first mixed with inoculum and made into slurry and the experiment was carried out at ambient temperature in both the reactors. Water hyacinth was added to the second reactor to enhance the process of biomethanation and the gas production from both the reactors was measured. Results revealed that the gas production from the second reactor was slightly more compared to the first reactor. At the end of the digestion period, COD was reduced to 70 % in both reactors and there was total solids reduction of 56 % and 60 % in reactor 1 and reactor 2 respectively.