Biogas from waste material

Production of biogas, i. e. methane, from waste materials,... 

The methane-rich biogas from lignocellulosic materials comes mostly from hemicelluloses and cellulose [45]. The production of biogas from lignocellulosic materials was dependent on the performance, cost effectiveness, and product generation of pretreatment process. Hence, the methane yield per wastes volume can be further improved. 

With similar thoughts in mind, ambitious programs for biogas production from various waste materials were initiated (Graz University of Technology, Vienna... 

Ethyl lactate is produced by esterification of lactic acid with ethanol and this process can be done in biorefineries. In these plants, biomass as raw material is transformed into biobased products such as proteins, acids, alcohols, fibers or energy (biogas). In the case of ethyl lactate, both ethanol and lactic acid can be produced in biorefineries from a variety of biomass crops, such as sugar, starch or cellulosic feedstocks, particularly from wastes, resulting also in an economic revaluation for by-products. 

In continuous and semi continuous-flow systems waste go into reactor continuously or at certain intervals. The introduction of a new portion of feedstock is accompanied by a simultaneous discharge of an equivalent quantity of the batch of reactor. Part of the material leaves the reactor without being completely decomposed. Parameters determined in these systems are called biogas/methane yield. Some results of laboratory estimation of biogas production from waste are presented in Table 2.5. 

Biogas can be obtained from digesting the organic material of municipal solid wastes (MSW). The composition of MSW varies by the somce of waste however, in all cases the major constituents of MSW are organic in nature and the organics accoimts for more than 50% of MSW. The economic exploitation of methane is worthwhile after one year from the start of the landfill operation. 

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