Abstract
Operational problems during the start-up of upflow anaerobic sludge blanket (UASB) reactors are little reported in the literature. In this study, operational problems during the initial operation of UASB reactors are discussed. Major problems encompass the gas entrapment in the granular sludge bed, formation of scum and crustation, and maintenance of hydraulic retention times (HRTs) at very low flow rates. The experience related to the effect of these problems is addressed in this study together with insight into the remedial measures. Gentle mixing at regular intervals during the initial period is stressed.
