Organic wastes can become a great energy source, renewable and ecologically friendly, for our country, Russian scientists say.

In order to produce energy from organic wastes there exists a widely spread technique – anaerobic microorganisms digest biomass and emit biogas, a mixture of methane (50-70%) and carbon dioxide (30-50%). In Russia such enterprises aren’t spread widely enough, however, materials for mentioned process are in plenty.

There are at least three sources for biogas production: wastes of the agricultural sector, sewage sludges and solid domestic wastes. Statistical data and calculations reveal 773 million tons of wastes, which domestic agricultural sector produces every year. Microbial transformation of this Everest of wastes can give 62.5 billion cubic meters of biogas, which is equivalent to 31 billion tons of gasoline or diesel fuel or 106 gigawatt/hour of electric energy. Thus, Russian agricultural sector can fully cover its energetic needs and, what is more, provide energy for rural population of Russia. Unfortunately, this enormous potential still remains a potential.

80 million cubic meters of sewage sludges, produced in Russia annually, can give 0.6 billion cubic meters of biogas – enough to meet energetic requirements of waste treatment facilities, which are quite energy consuming today.

In Russia solid domestic wastes, up to 40% of which are easily degraded organic substances, are taken to dumps. Such actions are banned in many countries of the European Union, because heaps of domestic wastes produce methane, a greenhouse gas. A reasonable approach to this problem is taking this process under control and preventing pollution of Earth’s atmosphere with methane and the ground – with wastes. 35 million tons of solid domestic wastes can produce 2.1 billion cubic meters of biogas and 2.3 million tons of high-quality fertilizers. Both products of microbial transformation can be successfully used in municipal economy, but first city dwellers should learn to sort wastes.

Traditional technique of methane production is not the only one means for releasing energy from biomass via anaerobic fermentation. Same principles work for microbial fuel cell. The simplest microbial fuel cell consists of two compartments, one with cathode and second with anode. Microorganisms of anode compartment oxidize organic matter, producing electrons and protons, which head for oxygen, located in the cathode compartment. However, compartments are separated with a membrane, which is transparent only for protons. Electrons have to move along the outer circuit, thus generating electric current. When electrons reach the cathode compartment, they react with oxygen and protons, thus forming water. Modern microbial fuel cells produce very small amount of energy, but they can soon turn from a toy into a real fuel cell. Fuel cells work on any organic matter, which can be decomposed by microorganisms.

Bioenergetics has wide perspectives in Russia, however, its successful realization requires united efforts of financial, intellectual and political sectors of our country.

Source: Russian Science News

Kizilova Anna