Minimization of Short-Circuiting Flow through Upflow Anaerobic Sludge Blanket Reactor

Abstract

Performance data of upflow anaerobic sludge blanket (UASB) reactors treating different types of wastewater have been analyzed. A completely stirred tank reactor (CSTR) model with bypass flow was considered for evaluation of the behavior of sludge bed as well as the whole reactor. It demonstrated that the sludge bed in a UASB reactor behaves as a completely stirred tank reactor with bypass flow. The reactor performance has been shown to depend on the short-circuiting flow through the sludge bed. However, the short-circuiting flow depends on design and operational conditions of the reactor. To find out the relationships of various parameters with short-circuiting flow through the sludge bed, dimensional analysis was carried out. Principal component analysis was carried out by taking short-circuiting flow, concentration of the influent, superficial gas velocity, height of the sludge bed, concentration of the biomass in the sludge bed, and flow rate of the influent into consideration. Analysis reveals the relative importance of the parameters on the short-circuiting flow.