[Production of Methane in Anaerobic Digestion of Organic Waste of Vegetable Processing Facilities].

The article concerns converting waste from vegetable processing facilities into methane in anaerobic reactors with a small amount of inoculum (8.4%). Anaerobic digestion of vegetable waste with a high content of organic acids and carbohydrates makes it possible to achieve a methanogenesis productivity of 273­436 L CH4/kg of volatile solidis, which is comparable to or higher than the productivity of such reactors in the world (according to the literature). The contents of ammonia nitrogen and soluble phosphorus in the form of on undiluted substrate basis in the digested vegetable wastes ranged from 3.39 to 5.06 and from 0.78 to 1.03 g/L respectively. Thus, mineralized vegetable waste can be used as an organic fertilizer with a high nutrient content. The results show the feasibility of the technology of conversion of organic waste from vegetable processing facilities into methane and organic fertilizer in anaerobic fermenters (digesters).

[Intensification of Microbial Decomposition of Organic Fraction of Municipal Waste: Laboratory and Field Experiments].

Methods of intensifying the anaerobic microbial decomposition of the organic fraction of municipal solid waste (MSW) on an MSW landfill and in anaerobic reactors were studied. It was discovered that it is preferable for the initiation and stabilization of the process of anaerobic digestion of organic waste in laboratory bioreactors at 20 and 50 degrees C to use a mixture of activated suspension of soil from the anaerobic zone of the landfill and digested sewage sludge. Stimulation of methanogenesis was shown in field conditions when digested sewage sludge was added directly into the upper layer of anaerobic zone of the landfill. The investigation of methane production during fermentation of concentrated food waste with a mixture of excessive activated sludge in the laboratory under thermophilic conditions (50 degrees C) has shown that the main problem at the first stage of the process was the acidification of the digested mixture due to the accumulation of volatile fatty acids. It was shown that for stable operation of the bioreactor under thermophilic conditions the amount of inoculum added during the start up should be no less than 30%-50%--based on volatile suspended solids. A sharp decrease in the digestion temperature from 50 to 20 degrees C did not cause methanogenesis termination, since the thermophilically fermented biomass contained both thermophilic and mesophilic methanogens.