Food waste digestate composting: Feedstock optimization with sawdust and mature compost.

Direct land application of food waste digestate (FWD) leads to 60-70% of nitrogen loss through NH volatilization due to its innate characteristics like high ammonium nitrogen (NH-N) (6000 mg/kg dry matter) and high moisture content (75%). Hence, bio stabilization of FWD through composting is a promising solution to curb the environmental and occupational hazards. Hence the aim of this study was to assess the feasibility of using sawdust and/or mature compost as a bulking agent to achieve effective composting. The results showed that mixing of FWD with sawdust alone or together with mature compost could produce quality compost with reduced NH-N (<700 mg/kg dry matter) and increased seed germination index (>80%) within 2 weeks of co-composting. Composting FWD with both sawdust and mature compost effectively reduced ~ 83% of NH volatilization demonstrating that this approach can effectively produce mature nitrogen enriched FWD compost.