Economic Plating Waste Treatment by Reverse Osmosis
573
Table II
Selected R.O. Performance Data for Industrial Nickel Recovery
Operating Pressure
Operating Temperature Range
Pump Delivery Rate, Vj
Feed pH
Feed Flow Rate, Vf
Permeate Flow Rate, Vp
Concentrate Recovery Rate, V c
R.O. Conversion Factor for Water
*Membrane Rejection Efficiency for Ni, R
**R.O. Retention Efficiency for Ni, 17
R is defined as
77 is defined as
xlOO
/CAV-Cp\
\ CAV /
V ^ -
V P
C P x l O Q
VfCf
450 psi
36 - 47°C (ambient frequently >32°C)
3585 gal/day (2.5 gal/min)
4.0 ±0.5
1215 gal/day
1065 gal/day (corresp. to 10.7 gfd)
150 gal/day
88%
99.8 ±0.1%
98.3 ±0.7%
Footnotes
(i)
(ό)
(iii)
CAV is the average concentration of Ni in the solution in contact with the membrane. It is taken, as a first approximation, to
be the arithmetic mean of Q and C c , the inlet and outlet concentrations across the modular assembly.
Ci is readily calculated from a mass balance over the recycle loop
of the R.O. unit (Fig. 2), assuming constant pumping rate V| (this
was periodically checked)
Thus,ViCi = V r C c + VfCf
V r , the recycle flow rate is given by V r = W\ — Vf
where Vf = V c + V p