How is the 'recovery rate' in a reverse osmosis system calculated?

The recovery rate in a reverse osmosis (RO) system is calculated as the ratio of the permeate flow rate to the feed flow rate, expressed as a percentage. The recovery rate indicates the proportion of the feed water that is recovered as product water (permeate) after the RO process. The formula for calculating recovery rate is: Recovery Rate (%) = (Permeate Flow Rate / Feed Flow Rate) 100. Permeate flow rate is the volume of permeate produced per unit of time, typically measured in gallons per minute (GPM) or cubic meters per hour (m3/h). Feed flow rate is the volume of feed water entering the RO system per unit of time, measured in the same units as the permeate flow rate. For example, if an RO system has a feed flow rate of 100 GPM and a permeate flow rate of 50 GPM, the recovery rate would be (50 GPM / 100 GPM) 100 = 50%. This means that 50% of the feed water is recovered as product water, and the remaining 50% is discharged as brine (concentrate). The recovery rate is an important parameter for RO system design and operation, as it affects the system's water production capacity, energy consumption, and fouling potential. Higher recovery rates generally lead to lower energy consumption and less waste water, but they also increase the risk of scaling and fouling.