All the organic wastes that are naturally generated in the matter cycles of the planet are transformed and take benefit for the environment trough degradative biological processes, either in the presence of oxygen (aerobic) or in its absence (anaerobic). In both cases there are different groups of micro organisms who realized the process, mainly bacteria and fungus.
The biological degradation of organic wastes in the presence of oxygen is known as composting. It is the process for which the organic remains are transformed in a natural way in humus, that will allow and will contribute to the development of new biomass, closing the natural cycle of the matter. Being a process that happens in presence of free oxygen has the advantage to do not need to be confined or isolated from the atmosphere.
The anaerobic degradation, also known as methanization, has as main characteristic that only happens in the absence of oxygen. Because of that in nature only it takes place in specific places, mainly in liquid environments where all the dissolved oxygen has been consumed. As intermediate product of the process it is generated a biogas, mainly composed by CO2 and CH4 (methane). The possibility of energetic use of this methane has generated a strong interest, from the economic point of view, in this process.
The current systems of biological treatments for organic wastes have not made more than use these natural processes, trying to optimize their outputs, mainly including monitoring and controlling mechanisms. The application of these technologies at an industrial scale generally obtained not very satisfactory results, because it was not strange that there was a rejection, and even an important lack of knowledge, especially about the process. If it is adding to the enormous dimensions and wastes reception capacity of some of those facilities, a little better could be understood the problems and poor successful that some of them have had, as well as the poor quality and utility of the final obtained product from them.
Problems in the treatment facilities
In numerous occasions the design and sizing errors that happen in the facilities, originated by an ignorance practice of the characteristics and necessities of the wastes that pretends to be deal with, are easily detected and fixed when the project is not in the execution phase yet. Once the facility has been built is more complicated and expensive to correct the design errors.
Another shortages that are usually found in the facilities, especially in the newest ones, are the lack of formation of the crew in charge, either because a lack of experience in the field or because their knowledge is limited to theoretical one. In facilities that have been working for a time, there are lots of their knowledge that have been gain trough practice by means of test and failure, but without knowing the real reasons or the foundations for that practice could work or not.
Any fermentable organic waste is susceptible to be treated by biological degradation systems or methods. However, the variety in the types, characteristics and composition of the residues is really wide, especially if the biowastes generated in the industrial activities are considered. There are certain biowastes very easily degradable that could present problems to be composted, as they are the protein residues coming from animal corpses, rejected eggs from poultry farms, slaughterhouse remains, etc…., aside from which as soon as they almost would not produce compost, they could bring about problems by excessive and uncontrollable emissions of ammonia and other gases. Only in the cases of controlled amounts of entries of these biowastes in facilities that have sufficient amount of lignin or cellulose type of residues that they can be mixed with, they could be accepted without risks. Nevertheless its processing by anaerobic processes not only would diminish these problems of gas discharges when being realised in a confined and isolated space, but also that the productivity of methane rich biogas of this type of residues is very high, which it would allow an important energetic advantage from these biowastes.