RESUMO
Direct land application of food waste digestate (FWD) leads to 60-70% of nitrogen loss through NH3 volatilization due to its innate characteristics like high ammonium nitrogen (NH4+-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 NH4+-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 NH3 volatilization demonstrating that this approach can effectively produce mature nitrogen enriched FWD compost.
Assuntos
Compostagem , Eliminação de Resíduos , Alimentos , Nitrogênio/análise , Solo , Madeira/químicaRESUMO
High concentration of NH4+-N in food waste digestate (FWD) produced from biological treatment of food waste is considered as a major threat on the composting process resulting in production of immature compost. Hence, a laboratory batch composting study was conducted to examine the feasibility of using biochar as a physical additive to ameliorate the inhibitory effect of NH4+-N and to mitigate the nitrogen loss during FWD composting. FWD was co-composted with tobacco biochar at a dosage of 0%, 2.5%, 5% or 10% (dw) in bench-scale composters with a controlled aeration system. The addition of 10% biochar enhanced the degradation rate resulting in 44% higher carbon decomposition than the control. Besides, 10% biochar amendment reduced NH3 and N loss by 58% and 5%, respectively and significantly reduced NH4+-N content to HKORC limit of < 700 mg/kg dw within 5 days showing the beneficiary impact of biochar addition.