Anaerobic treatment of food waste in pilot scale

For this work, a pilot scale anaerobic digester was used to assess the treatability of food waste from a canteen. The digester was operated for 720 days, and its efficiency in removing organic matter and suspended solids as well as producing biogas were assessed. At the beginning of operation, the digester failed and alkalinity buffering was required until stabilization. A maximum chemical oxygen demand (COD) and total solids removal efficiency of 71% and 87% were, respectively, found for the organic loading rate of 0.59 kg COD m⁻³ d⁻¹. The maximum gas production rate and specific gas production were 0.4 m³ m⁻³ d⁻¹ and 0.76 m³ (kg TVS)⁻¹, respectively, with a methane average of 60% in the biogas composition. Although achieving satisfactory levels of pollutant removal, the effluent characteristics particularly for COD and ammonia nitrogen indicated that recirculation is the best option to use effluent.