The growing sector of agricultural biogas plants in Poland and Europe is facing a serious problem of managing digestate. In Europe there are currently about 14,500 biogas plants. The fact that both the EU Waste Directive and the Polish Act on Waste qualifying digestate as waste does not make the situation any easier. The simplest method of developing digestate is to directly spread it on fields. The implementation of this method is impeded by limiting the areas of cultivation due to the high content of organic nitrogen and odor emission. The growth in the number of biogas plants will be associated with the increase in the digestate disposal problem. Alternative methods of fertilization involve the separation into solid fractions and liquid fractions. After composting, solid fractions may be used as fertilizer, sometimes as solid granulation. The use of solid fractions of digestate for energy purposes involves using them as feedstock for pellets and briquettes production. The gasification and carbonization are two of several possible methods of thermochemical treatment of biomass.