Modeling the liquid flow in up‐flow anaerobic sludge blanket reactors

By means of stimulus‐response experiments an Li+ tracer, models for the fluid flow in a 30‐m3 UASB reactor, used for the anaerobic treatment of wastewater, were tested. From the model with the best fit it could be derived that both the sludge bed and the sludge blanket can be described as perfectly mixed tank reactors with short‐circuiting flows; the settler volume acts like a plug‐flow region.