Process Calculations GATE-2013
Common data for Q 1 & 2:
A reverse osmosis unit treats feed water (F) containing fluoride and its output consists of a permeate stream (P) and a reject stream (R). Let CF, CP, and CR denote the fluoride concentrations in the feed, permeate, and reject streams, respectively. Under steady-state conditions, the volumetric flow rate of the reject is 60 % of the volumetric flow rate of the inlet stream, and CF = 2 mg/L and CP = 0.1 mg/L.
Q 1: The value of CR in mg/L, up to one digit after the decimal point, is ___________.
Q 2: A fraction f of the feed is bypassed and mixed with the permeate to obtain treated water having a fluoride concentration of 1 mg/L. Here also the flow rate of the reject stream is 60 % of the flow rate entering the reverse osmosis unit (after the bypass). The value of f, up to 2 digits after the decimal point, is ____________.