Abstract
Upflow anaerobic sludge blanket (UASB) process is one of the potential biological processes for the treatment of dairy waste especially in the developing countries. One of the factors of major concern in anaerobic systems is their long start-up periods. In this study, start-up of UASB reactors with activated and methanogenic granular sludges was examined. The results showed that volumetric loading rates that could be achieved at 80% COD removal efficiencies were 3.7 and 8.5 g-COD/l⋅d while time taken to establish these rates were 60 and 30 days, respectively for reactors started-up with activated and granular sludges. A solids loading rate of 1.25 to 1.5 g-COD/g-VSS⋅d was found to be a guide value for UASB reactor seeded with activated sludge. The results of this study indicated that the UASB reactors can successfully be started-up with granular or activated sludges but use of granular sludge is advantageous.
