The problem of biogas formation and using with high contents in mehtane (CH4) and hydrogen (H2) as a renewable energy agent is a serious challenge for the experts in various fields, in view to resolve a fundamental ecological-economic component of sustainable development – transition to the renewable energy sources. As it is known, hydrogen emission occurs on the acetogenic phase of the organic matter anaerobic digestion, due to the acetogenic bacteria activity (Methanobacillus omelianskii etc.), splitting the alcohols and greasy acids, which are formed in the hydrocarbons degradation of vegetable matter. The hydrogen emitted is mostly consumed in the methane formation reacton: 4Н2+ СО2 → СН4 + 2Н2О, and is accumulated in biogas. When its quantity exceeds certain concentration (up to 10%) in biogas, the anaerobic fermentation is inhibited. The amount of CH4 in biogas depends on the rate of this Н2 level attaining. This fact is responsible for the technological difficulties in reaching of more than 70% methane in biogas, its amount in most cases being about 60%. The methanogenesis inhibition prevents the further formation of hydrogen. The essence of phyto-chemical intensification of biohydrogen and biomethane formation, presented in this work, consists in the anaerobic fermentation of agro-industrial wastewaters with high contents in digestible organic substances, in the presence of stimulating additives of phytochemical nature. The vinasse resulted from the alcohol distillation from wine material was used as a biomass – a renewable vegetable substrate. The biologically active vegetable substances of isoprenoid nature have been tested as stimulating additives in anaerobic digestion. These substances, being applied in the amounts of 1x10-3- 5x10-4 mass % of a reacting mixture, have either partially inhibited the methane formation, promoting the accumulation of hydrogen in biogas, or have stimulated the methane formation and appropriate increase in methane concentration. Some spirostanolic substances and triterpenic glicozides introduced in the anaerobic digestion mixture, have significantly reoriented the methanogenesis process towards the selective formation of molecular hydrogen. In the presence of mentioned biostimulators, hydrogen contents in the biogas volume on the 12th day of digestion have reached about 40 and 68% for spirostanolic stimulator and triterpenic glicozide, accordingly. The process was shown to be more efficient within the range pH=5.2 ÷7.5 under the mesophylic thermal conditions. The other phyto-chemical compounds of triterpenoid series (squalene, betulinol), being introduced in the agroindustrial waste waters, have intensified the anaerobic digestion in the laboratory tests up to 2-3 times, with the increase in CH4 contents in biogas up to about 90%. Having revealed this phenomena, we have focused our studies on biogas emission intensification as an agent for „green energy” production in the processes of agroindustrial waste waters and liquid wastes purification with the contents in hydrocarbons, through the anaerobic digestion. The further research have been concentrated on three directions: 1. Biochemical formation of hydrogen, 2. Phyto-chemical intensification of biomethane formation and emission, 3. Winery waste water treatment through the beneficial ecologic-economical process of the simultaneous formation of biogas with high contents in methane or hydrogen.
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The problem of biogas formation and using with high contents in mehtane (CH4) and hydrogen (H2) as a renewable energy agent is a serious challenge for the experts in various fields, in view to resolve a fundamental ecological-economic component of sustainable development – transition to the renewable energy sources. As it is known, hydrogen emission occurs on the acetogenic phase of the organic matter anaerobic digestion, due to the acetogenic bacteria activity (Methanobacillus omelianskii etc.), splitting the alcohols and greasy acids, which are formed in the hydrocarbons degradation of vegetable matter. The hydrogen emitted is mostly consumed in the methane formation reacton: 4Н2+ СО2 → СН4 + 2Н2О, and is accumulated in biogas. When its quantity exceeds certain concentration (up to 10%) in biogas, the anaerobic fermentation is inhibited. The amount of CH4 in biogas depends on the rate of this Н2 level attaining. This fact is responsible for the technological difficulties in reaching of more than 70% methane in biogas, its amount in most cases being about 60%. The methanogenesis inhibition prevents the further formation of hydrogen. The essence of phyto-chemical intensification of biohydrogen and biomethane formation, presented in this work, consists in the anaerobic fermentation of agro-industrial wastewaters with high contents in digestible organic substances, in the presence of stimulating additives of phytochemical nature. The vinasse resulted from the alcohol distillation from wine material was used as a biomass – a renewable vegetable substrate. The biologically active vegetable substances of isoprenoid nature have been tested as stimulating additives in anaerobic digestion. These substances, being applied in the amounts of 1x10-3- 5x10-4 mass % of a reacting mixture, have either partially inhibited the methane formation, promoting the accumulation of hydrogen in biogas, or have stimulated the methane formation and appropriate increase in methane concentration. Some spirostanolic substances and triterpenic glicozides introduced in the anaerobic digestion mixture, have significantly reoriented the methanogenesis process towards the selective formation of molecular hydrogen. In the presence of mentioned biostimulators, hydrogen contents in the biogas volume on the 12th day of digestion have reached about 40 and 68% for spirostanolic stimulator and triterpenic glicozide, accordingly. The process was shown to be more efficient within the range pH=5.2 ÷7.5 under the mesophylic thermal conditions. The other phyto-chemical compounds of triterpenoid series (squalene, betulinol), being introduced in the agroindustrial waste waters, have intensified the anaerobic digestion in the laboratory tests up to 2-3 times, with the increase in CH4 contents in biogas up to about 90%. Having revealed this phenomena, we have focused our studies on biogas emission intensification as an agent for „green energy” production in the processes of agroindustrial waste waters and liquid wastes purification with the contents in hydrocarbons, through the anaerobic digestion. The further research have been concentrated on three directions: 1. Biochemical formation of hydrogen, 2. Phyto-chemical intensification of biomethane formation and emission, 3. Winery waste water treatment through the beneficial ecologic-economical process of the simultaneous formation of biogas with high contents in methane or hydrogen.
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