Figure 7-8. Reverse osmosis product staging.
membrane modules. While higher flow rates will tend to
Banking of membranes usually require a flow restraint
clean membranes, excessive flow can fatigue or fray
on the brine reject of each module in the bank. A pigtail
both spiral and hollow fine-fiber membranes. Low flow
rates allow the concentrated brine to stagnate, which
headloss. This pressure drop maintains a balanced flow
leads to scaling and fouling of membrane surfaces.
of brine out of each membrane module in the bank.
Unbalanced flow can shorten the useful life of