Author(s)

K.C. Lin & J.Z. Yang

Abstract

A UASB reactor has been segmented into three serial completely-mixed zones based on Li* tracer results: the lower sludge bed with bypass, the upper sludge bed without bypass and the sludge blanket. Steady-state acidogenesis and methanogenesis have been formulated by simple explicit model equations for the three zones. First-order COD reaction, autotrophic and heterotrophic growth/decay, unionized VFA inhibition, pH effects and biogas production were considered. The model has been calibrated and verified with experimental data. 1 Introduction Since the development of the upflow anaerobic sludge blanket (UASB) process by Lettinga et al. in 1972 [1], many experimental studies have been conducted on the

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