We are running an RO system with NaCl in the aqueous feed at 0.035 wt frac. This approximates the concentration of sea water, but sea water is much more complex. Typically, the highest cut for RO of sea water is approximately 0.50 to 0.55. In the United States, the EPA lists the preferred salt weight frac. in drinking water as 0.00050. In other countries, a higher drinking water maximum salt concentration is used. a. If xfeed=0.035, Xp = 0.00050, and θ' = 0.55, what value of the retention R (including concentration polarization effects) is required?
b. If xfeed=0.035, Xp = 0.00100 and θ' = 0.55, what value of the retention R (including concentration polarization effects) is required?