**Acknowledgements**

**Figure 16.** Concentration of undissolved substances in the anaerobic reactor in the biogas plant.

the biogas plant operation.

192 Advances in Silage Production and Utilization

bioethanol from cereals).

biogas a surplus value of landscaping.

**5. Conclusions**

Crude glycerol loading of 12.1% of the total loaded VS had a positive and stabilizing effect on

The obtained laboratory and full scale results showed that maize silage is a suitable substrate for anaerobic digestion and biogas production. This is confirmed also by thousands of biogas plants in Europe, which use maize silage as the main substrate. Thus, it can be concluded that maize silage as the most widely used substrate for biogas production is a fact of presence. However, biogas production from this substrate is not sustainable nor is the production of the first generation biofuels produced from food commodities (e.g. biodiesel from edible oils, or

The advantage of using maize silage for biogas production is because of its high yield per hectare and high specific biogas production. The main disadvantage is that maize used for biogas production cannot be used as designed in human or animal nutrition. Such competition deforms also its price and maize silage becomes a scarce commodity. Moreover, mass growing of maize as a monoculture occupies arable land for growing other crops and increases the need for fertilization and plant protection. These negative effects were also presented by the authors from the Karlsruhe Institute of Technology, Germany [33]. The main aims of their project were "Landscaping instead of monoculture" and "Grass is an alternative to silage maize in biogas production." It is evident that grass hectare yields or specific biogas production cannot compete with maize silage; however, it is a sustainable alternative to maize silage and makes This contribution is the result of the project implementation: Finalizing of the National Centre for Research and Application of Renewable Energy Sources, ITMS 26240120028, supported by the Research & Development Operational Programme funded by the ERDF.
