TRACER STUDIES IN A LABORATORY AND PILOT-SCALE UASB REACTOR

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.