Residence time distribution studies on laboratory and pilot scale upfl
ow anaerobic sludge blanket reactors (UASB) were carried out in order
to measure and evaluate the influence, on the reactor's hydraulic perf
ormance, of the biogas collection device position (gas-liquid-solid se
parator), of the presence of granular sludge and of the arrangement of
the influent distribution system within the reactor. The main purpose
of the pilot scale experiment was to assess the influence of the biog
as collection device on the reactor hydraulic performance accurately.
The results show that if the biogas collector system is located in a l
ower position (nearer to the sludge bed), the dead volume fraction dec
reases and a better performance of the settler could be obtained. In a
ddition, it can be appreciated that the mixed now pattern has more dea
d volume fraction than a plug flow hydraulic pattern.