The determination of biogas potential of organic materials and its rate of decomposition contributes to much better and more complete characterization of waste materials. Most methods for determination of biogas potential are applicable to a wide range of organic materials. The analysis of biogas potential of organic materials allows the determination of the optimum ratio of the co-substrates, the determination of the dynamics of the anaerobic degradation process and the determination of the eventual occurrence of process inhibition. These parameters and properties should have an important role during decision-making about investing in the construction of plants for the anaerobic digestion of waste materials and the biogas potential is a quality indicator for the justification of the application of these technologies in the waste treatment and its energy recovery.
Methods
There are several laboratory methods for the determination of the biogas potential of organic materials and these methods can be divided into two basic groups: pressure and volumetric methods. As standard, these methods can be performed during 21, 90, 100 and 270 days. During the pressure methods, the volume of biogas is obtained by measuring the pressure in an enclosed reactor while the volume of biogas from the volumetric methods is obtained directly from the reactor eudiometer, plastic bags or gas meter which can directly measure the volume of methane without carbon dioxide and hydrogen sulfide.
In our own laboratory the biogas potential is determined by the volumetric method for the determination of the GS21 parameter. The analysis is usually conducted during 21 days and is applicable for almost all types of organic substrates. The results obtained from the biogas potential tests are expressed in NL/kgDM.
