Biobased Fertilizers - Comparison of Nutrient Content of Digestate/Compost

Agriculture is the main source of soil degradation processes in Bulgaria. Therefore, soil improvement is an important task. The possibilities for using composted either municipal waste or residues from biogas production for soil improvement in Bulgaria, suggested by the development of INEMAD (Improvement of Nutrient and Energy Management through Anaerobic Digestion) project, should be assessed and popularized. The advantages and disadvantages should be analysed and discussed. This paper uses the results of two previously published papers by AUP within the framework of INEMAD where the possibilities for production and sale of compost from municipal waste and digestate from biogas by anaerobic digestion of animal manure are discussed.

The possibilities for biogas production in Bulgaria as well as the potential for use of digestate as fertilizer are discussed. At present these options are not yet feasible for Bulgaria because of the high prices of anaerobic digestion plant and the insufficient quantities of animal manure. Advantages of waste processing are multiple, on one hand the processing of municipal waste produces compost of organic origin and can be used as a soil improver to recover nutrients and improve structure while at the same time this allows reducing the area of dunghills, unpleasant smell, and Greenhouse Gas emissions.