The application of digestate from biogas production could be a cost-saving and eco- friendly method of disposal of biodegradable organic waste and recycling nutrients for sustainable agricultural production. The aim of this study is to characterize solid digestates from eight small-scale fixed dome digesters fed with mixed organic wastes and operated on the semi-continuous feeding method. The physico-chemical characteristics, plant nutrients and heavy metals were investigated. The nutrients content and the physico-chemical characteristics of the digestates indicate that they contained significant amounts readily available formsof essential major plant nutrients (N, P, S, Ca and Mg) that can enhance plant growth when applied to soils. The digestates contained some micronutrients (Co, Cu, Fe, Mn, Mo, Ni and Zn) as well. However, these digestates may only be applied as partial replacementfor mineral fertilizers due to the low concentrations of some of the nutrients. The heavy metals (As, Cd, Hg, Pb) were also present, but in concentrations many times lower than the recommended maximum guideline limits
Key words: Biodigester, Digestate, Biofertiliser, Nutrients, Manure, Food waste, Macronutrients, Micronutrients
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