Utilization of Biogas

Natural wastes with a high salary in organic substances represent near the harmful effect from chemical pollutants also a high environmental impact. The wastes are developed by organic process and they can be disposed on biological way. The nature of the treatment exists in each case in the fact that the organic materials for certain organisms serve as food, which these decompose during the metabolism process into such substances, which represent no more danger for the environment. The fundamental difference between the procedures is that whether the micro organisms taken part in the dismantling of the organic components work under aerobes or anaerobic conditions. Under aerobes conditions with the dismantling as gaseous metabolic product mainly carbon dioxide is set free, under anaerobic conditions methane. As the aerobes dismantling processes, the biological degradation and the ventilated waste water treatment are well-known. The compost or the sewage sludge developing at the end of the process can be used as a nutrient for the agriculture.

The anaerobic dismantling procedures have found in Hungary still no spreading, except some putrefaction washbasins in waste water purification enterprises. Under appropriately anaerobic conditions metabolic products are developed, which distinguished it from the aerobe decomposition and by their energetic use the energy balance of the entire system positively precipitates.

Principle of the emergence of fermentation gas

Fermentation gas develops with the biological dismantling of organic substances under anaerobe conditions. The developing process can be divided into two phases: The first phase is a fermentative biochemical process (sour fermentation), with which the macromolecules are diminished and split up by the organic substances. The dismantling takes place via acid bacteria and mushrooms. In the second phase, further bacteria-groups decompose the simpler molecules. Thus the organic substances are divided by these bacteria into soluble fatty acids, alcohol, carbon dioxide, hydrogen and hydrogen sulfide. The result of these processes is the fermentation gas usable for energetic purposes.

The final product of the process is a marsh phase ferment, such a named bio dung. This manure can be used as source of nutrient in the agriculture.

Basic materials for the production of fermentation gas

All organic substances moved by micro-organisms are suitable. For the safe operation it is important that the composition of the mixture arriving into the fermenter does not change, so that a balanced micro-biological process can be guaranteed. A correct carbon nitrogen relationship of the nutrient is important, which adapt by addition of various substances.

Other important parameters for the process are the right pH-value (ideal is an pH-value in the neutral area), the dampness (dry substances: 0,1-60%) and the temperature (30°-65°C). These parameters can moves as a function of the used technology within the values named in the clips.

Energetic use of fermentation gas

The heat value of 1 m³ fermentation gas amounts to 22 MJ, this corresponds to the heat value of 0.66 m³ natural gas, 0.61 l of fuel oil or an electric energy of 6.1 kWh. The application of fermentation gas for energetic purposes is possible with all technologies in which natural gas or PB gas is used. In KWK power plants approx. 40% of heat energy and 40% of electric energy can be won. In KWK power plants approx. 40% of heat energy and 40% of electric energy can be won.  From the above executions it comes out that the problem of the disposal of wastes (which represent untreated an environment danger) can be solved by the help of anaerobic dismantling processes. The result of the process is an useful product, which be won of the danger substances (bio dung, fermentation gas). The energy balance of the whole technology is positive. With this procedure it is not fallen back on fossil sources of energy. The produced and during the operation not used energy can be transmitted even to other customers. The law about the electric energy creates an appropriate legal and economic background. In the ideal case considerable yields can be achieved by the sales of the electric energy. Up to now the waste disposal was connected with expenses. For the purposes of the executions our firm with the establishment from fermentation gas arrangements takes over the following tasks:

• Condition collections of the waste treatment
• Creations of a feasibility study for a fermentation gas plant
• Elaboration of appropriate anaerobic reducing technologies
• Elaboration of optimal possibilities for the use of fermentation gas
• Planning of the whole technology
• Processing of the investment
• Operation of the finished plant