Kompogas - A New System for the Anaerobic Treatment of Source Separated Waste

Abstract

Fruit, yard and vegetable wastes from source-separated collection may vary in their total solid contents as a function of the season and of the sources of waste, e.g. high amounts of vegetables reduce the dry matter content significantly. A new digester system was developed to treat solid wastes from 15% to 40% total solids. It consisted of a horizontal CSTR-type of reactor with an intermittently operated, hydraulically driven stirrer taking up strong shear forces. Experiments in a pilot plant of 15 m3 net volume demonstrated a good performance at 55° C. With dry wastes of around 40% total solids specific gas production rates of 2.7 m3/m3*d at 40 days retention time up to 3.7 m3/m3*d at 13 days retention time were achieved. Pure vegetable waste gave a specific gas production of 3.5 m3/m3*d at 21 days retention time with a gas yield of 460 Liters per kg volatile solids. First experiments on the hygienizing effect of anaerobic digestion demonstrated that within two days of thermal treatment at 50° to 55°C the test organism Bacteriophage f2 was completely destroyed.