Bioreactors liquid mixing time

Liquid holdup in a bioreactor can be measured by recording the residence time distribution (RTD) of a tracer that is injected into the bioreactor (Boyer et al., 2002). By following the tracer, the liquid mixing can also be characterized. The most common RTD method involves injecting a small amount of salt tracer and then measuring... 

The early references to submerged membranes came from Japan. Ohkubo et al. (1988) obtained a patent describing hollow fibers in a vertical bundle in a vessel with air scour to vibrate the fibers to remove the cake. The first reported use of submerged hollow fibers in a wastewater membrane bioreactor (MBR) was by Yamamoto et al. (1989), who used fibers in a bundle and air bubbles for aeration, mixing, and induced liquid flow. Permeate was removed by suction. At that time the concept was more of a curiosity, but within a decade the submerged membrane has become the dominant approach for low-pressure membrane processing in the water and wastewater industry. 

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