Reverse osmosis membrane issues
Thread Content
I would like to ask everyone whether the Dow reverse osmosis membranes BW30LE-4040 and BW30-365 have any limitations on the minimum concentrated flow rate specified during their design What is it roughly? Does a better water quality mean that a smaller minimum flow rate for the concentrated water can be specified? Every time I ask the water treatment supplier who is preparing the plan for us this question, they don’t give me a clear answer.
Each membrane element has a minimum flow rate requirement for the concentrated water side, as the flow velocity must reach a certain level in order to remove any potential contaminants from the membrane at the end. The required minimum flow rate varies depending on the quality of water; generally, the better the quality of the water, the lower the minimum flow rate for the concentrated stream. These values are clearly stated in DOW Chemical’s manuals: for BW30-365 membranes, the minimum flow rate for the concentrated stream in RO-treated water is 2.3 m3/h, 3.0 m3/h for groundwater, 3.4 m3/h for surface water after conventional pretreatment, 3.0 m3/h for surface water after microfiltration/ultrafiltration treatment, and 3.6–4.1 m3/h for reclaimed water ； For the BW30LE-4040 membrane, the impact of water quality is minimal; basically, a concentrate flow rate of 0.7 m3/h is required. This post was last edited by tjsong on 2009-2-13 15:02]
What was said upstairs is very comprehensive; the minimum flow rate of the membrane is closely related to the quality of the water entering it. Dow only provides approximate design guidelines, which represent safe values.
Indeed, as mentioned on the second floor, it seems there is an explanation in “Water Treatment Technology”. Take some time to browse through it. Reference books are highly theoretical and can provide principle-based analysis. This post was last edited by Welcome on 2009-2-14 07:55]
To prevent pollution, it’s wise to be conservative in the design; having it a bit larger than what’s specified in the manual (as described on floor 2) gives more peace of mind.