Treatment of kitchen waste using a mobile thermophilic anaerobic digestion system

A mobile thermophilic anaerobic digestion (TAnD, 55 °C) system was developed to treat kitchen waste. A two-phase TAnD system was designed to fit in a 40 ft container (L × W × H = 1203 × 235 × 238 cm) with an initial designed capacity of 100 kg/d (assuming a solid content of 15%). During the grinding process, an equal amount of water was added to the kitchen waste (1:1 dilution) to maintain a manageable concentration and sludge flow conditions. The tested loading was up to 160 L/d. The system was operated at hydraulic retention times (HRT) of 5.6 and 25 days for hydrolysis and acidogenesis, respectively. The removal efficiencies of total COD (TCOD), suspended solids (SS), and volatile SS (VSS) were 72.5, 77.8, and 82.4%, respectively, with a specific gas production of 0.733 m3/m3d.