This paper discusses the aeration aspect of an ultrafiltration application involving immersed membranes creating. an airlift pattern. The continuous aeration commonly used with immersed membranes to mitigate the effects of fouling was compared with several new aeration configurations. These new aeration configurations changed the local aeration intensity and aerated sequentially in different locations under hollow-fiber modules. The relative performances of each new aeration arrangement were evaluated against the continuous aeration in transient mode with a bentonite suspension.