Vermicomposting is an established process to convert organic wastes into vermicastings suitable for plant growth. This research investigated the vermicomposting of anaerobic digestate with four different ratios of sawdust as a bulking material, for 75 days. The optimum proportion of anaerobic digestate to sawdust was identified as 70:30 based on worm growth and reproduction. Vermicomposting process increased the conversion of ammonium into nitrate when compared with control (
= 0.05). Vermicastings produced at the end of this experiment had significantly high N, NO
-N, P and K than the control (
= 0.05). There was significant reduction in pathogen levels by the worms (99%), and also a germination test undertaken showed an 83% increase in radish seed germination after vermicomposting when compared to raw digestate. The results indicated that vermicomposting with
is a sustainable technology to convert the anaerobic digestate into nutrient-rich, safe to handle vermicastings, which otherwise is a secondary pollutant.
Keywords: pre-stabilisation, anaerobic digestate, Eisenia fetida, germination index, sawdust, vermicomposting