Normalized permeate flow is one of the most sensitive forecasters of trouble in an RO system. Fouling can reduce the permeate flow rate. However, just measuring the permeate flow rate is insufficient because it varies with the feed water temperature, feed pressure, permeate pressure and feedwater conductivity (total dissolved solids, or TDS). Though all RO membrane manufacturers have their equations for determining the normalized permeate flow, several parameters are needed to develop this complex calculation: temperature, net driving pressure, pressure drop, permeate, feedwater TDS and permeate flow. This calculation corrects for temperature and pressure variations. The calculation, known as normalized permeate flow, adjusts the daily data readings to what they would be if the system were operating at startup pressure at 25°C.

The mass balance equation is:

(Feed flow1 x Feed Conductivity) = (Permeate Flow x Permeate Conductivity) + (Concentrate Flow x Concentrate Conductivity)

Feed Flow equals Permeate Flow + Concentrate Flow

This allows for daily comparisons of RO performance. Seasonal feedwater temperature variations can make fouling trends difficult to detect if the normalized permeate flow calculation is not used. For example, RO feedwater derived from surface sources becomes warmer during the springtime. This increase in feedwater temperature affects membrane performance by increasing the permeate flow rate. If the membrane elements are fouling at the same time (fouling causes a decrease in permeate flow rate), it is unlikely that this will be noticed until a change in seasons. At this time, the membrane elements may be severely fouled, with the permeate flow rate severely restricted.However, the tight porosity of the RO membrane limits its flow rate.

https://www.researchgate.net/deref/http%3A%2F%2Fwww.who.int%2F...%2Fdwq%2Fchemicals%2Fchlorateandchlorite0505.pdf

https://www.researchgate.net/publication/264180352_Removal_of_Perchlorate_Using_Reverse_Osmosis_and_Nanofiltration_Membranes

Article Removal of toxic ions (chromate, arsenate, and perchlorate) ...

Article Bacterial Perchlorate Reduction in Simulated Reverse Osmosis Rejectate

@khalid I am looking for chlorate, and the papers only cover perchlorate which has different chemistry.

@Prem I think you misunderstood my question.. I am asking mainly about chlorate rejection in RO not RO performance or fouling.. the papers u included don't discuss chlorate