startup of upelow anaerobic sludge blanket reactor for industrial wastewater treatment

up flow anaerobic sludge blanket (uasb) reactors have been increasingly used for industrial wastewater treatment. because of existing problems in startup step of these reactors, in this research the startup of a uasb in pilot scale and room temperature condition was studied. the total height of uasb reactor was 270 cm and effective height was 240 cm. diameter of the reactor in lower part was 20 cm (reaction zone) and 40 cm in upper part (solid-gas-liquid separator) five sampling ports with interval of 32 cm were provided and the effective volume of the reactor was 100 liters. septic tank digested sludge and cow manure were used for the seeding of uasb reactor. in the startup step of the reactor, volumetric loading was increased step by step. after 155 days granule formation was observed and after 215 days of the study the removal rate increased to 4.62 kg cod/m/ day. more than 98% of soluble cod removal was achieved in lower 160 cm of reactor.