Biomass
During the fermentation process of the biomass, according to the characteristics of the raw material, two coordinate products are produced. Besides energy, an organic substance remains, which can be used as a high-quality ripe manure, or so-called organic bio-manure. The bio-manure, which is a useful by-product, should be considered as an important factor when evaluating the profitability of biogas production.
When using the liquid bio-manure in agricultural area, manufactured with damp fermentation technology, the regulations must be kept regarding the application and use of the sewage mud in the agriculture. The traditional fertilization methods can only be used without health limitations if the fecal-coliform number is 1 piece per grams, no salmonella can be shown in 1000 grams and if there are no eggs of intestines worms and protonic cysts in 100 grams of bio-manure. The protective distances (eg. the approaching of waterworks protection zones, streets, buildings) in case of bio-manure fertilization are the same as in case of fertilization with the normal stable manure.
The doses of liquid bio-manure are to be determined in such a way that its nitrogen content stands in connection with the nitrogen quantity (N), which the bred plants can take up. Together with the N replacement of the soil, generally a bio-manure containing 200 kg/ha N quantity might be placed yearly. The duration of storage complies with the fertilization dates, so the liquid reservoir shall be sized to the storage of a quantity, enough for half year.
The liquid bio-manure handled with anaerobic processes shall be converted with further technological treatments which enables the whole agricultural use or harmless storage. The basic cases of utilization: direct use after storage by irrigation, or by injecting into the soil; after phase breakdown, after the storage of the liquid phases by irrigation, the production of compost from the solid stage by storage. The above mentioned methods of use or placement of the different consistency bio-manures are not widespread in the practice, so the applicable parts of the official regulations shall be observed implicitly.
The liquid phase of the production process of wet biogas or bio-manure (the so-called liquid bio-manure) is similar to the concentrated sewage or to the different liquid manures. The regulations regarding the sewages and mud, and the handling of liquid manure shall be observed accordingly. The differences between the two basic products (sewage and liquid bio-manure) are their origin, composition, health infectiousness and their harmful chemical effects. The bio-manure is the most practically produced organic manure, and besides its infinitesimal risk factors it has significant effects on the agricultural production.
The usage of the different bio-manures for the replenishment of soil power with the use of adequate processes means soil-biochemization instead of a simple chemization. With the help of this we utilize the possibilities offered by the natural eco system. Among the materials used for anaerobic fermentation the liquid manure and the sewage mud of slaughterhouse and communal sewage handling should be considered potential environment contaminating materials.
The maintenance of the environmental balance is top priority when handling the above mentioned contaminating materials. It is important to know what costs are required by the treatment and in what rate does this cost return in the proceeds of the produced useful materials. The anaerobic fermentation is economically justified because the value of the produced biogas and the utilizable other remainder materials can compensate the whole process which is profitable in case of methods producing energy sources and utilizing liquid manure.
The methanogenic treatment seems to be the most adequate handling and re-utilization method of the different forms of by-products (liquid, semi-moist and moist) and waste, because the anaerobic breakdown sterilizes the infectious and environmentally contaminating waste, and thus the raw materials are converted into valuable final products (methane gas and compost).
An other aspect of evaluating biogas production is the organic substance need of soil power maintenance. The dynamic balance of the accumulation and breakdown of the organic substances is the main characteristic of the natural eco systems. This dynamic balance can be ensured in ecological systems under human influence as well without environmental damages if we provide and maintain the essential conditions for the protection, supply and breakdown of the organic materials of the soil. This kind of production activity influences beneficially the land usage, and plant growing is an effective method of protection against wind and water erosion. Biogas production can ensure both energy production and the replenishment of the organic material need of soil power maintenance.