Evaluation of potential for anaerobic digestion of source-segregated domestic food wastes

Abstract

Anaerobic digestion (AD) is considered worldwide an effective technology employed for organic solid waste treatment such as source-segregated domestic food, providing environmental impacts reduction through bioenergy and biofertilizer production. In this work, it was evaluated the effects of organic load rates on the performance of an anaerobic digestor. The biodigester operated for 340 days, under fed-batch mode 1 (daily feeding) and fed-batch mode 2 (weekly feeding, three times per week) with different organic load rates (OLR): 3.28, 4.10, 5.00, 7.80, 7.98 and 9.64 kg. TVS/m . day. The AD was loaded with organic solid waste from a university restaurant and a previously acclimated inoculum. The results revealed the OLR of 4.10 TVS/m . day has presented the highest biogas (94.63 NL/kg.TVS) and CH4 (45.42 NL/kg.TVS) yields. In addition, it was observed higher biogas yield through fed-batch mode 2. Lastly, it was verified that high VFA/Alkalinity ratio, high VFA and ammoniacal nitrogen concentrations, foaming generation and absence of substrate pre-treatments influenced considerably biogas and methane yields.