Post on 10-Jan-2016
2011 Salinity Summit
Contributions to Permeation Resistance in a VSEP RO System Treating Brackish Water or Brine
Mark Benjamin and Wei Shi
Department of Civil and Environmental Engineering, University of Washington, Seattle, WA 98195
Reverse Osmosis (RO)
Reverse Osmosis (RO): Increasingly used in treatment of brackish water and brine for potable water
Fouling: Production
Time
Pressure
Time
Constant Pressure Constant Production
VSEP
Vibratory Shear Enhanced Processing
Source: New Logic Research Inc. Emeryville, CA
Shear
VSEP Applications
Landfill Leachate Manure Management Mining Petroleum Processing Pulp and Paper Desalination
VSEP Operation
Concentrate
Feed
Pump
Feed tank
Amplitude: 13°
Frequency: 55Hz
TMP: 140 psi
RO Feed Composition
Brackish water*
Brine: 10 times as concentrated
pH 8.0 Cl 175
Ca 275 as CaCO3 Ba 25
Mg 100 as CaCO3 Si 5
SO4 350 Fe 0.5
Na 175 Alk 150 as CaCO3
TDS 1050
* All units in mg/L, except for pH
Permeate FluxBrackish solution
0
10
20
30
40
50
0.0 0.2 0.4 0.6 0.8 1.0
Recovery
Flu
x (L
/m2-h
)
w/ vibrationw/o vibration
Permeate Flux
Brine
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0
5
10
15
20
25w/o vibrationw/ vibration
Recovery
Flu
x (
L/m
2-h
)
Resistance Breakdown
Rm
RTOT
Rπ
RFRF
= RTOT –Rm –RCP–Rπ
RCP
Contributions to Resistance
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 0
10000000000000
20000000000000
30000000000000
40000000000000
50000000000000Membrane
Osmotic P
Fouling
CP
Total
Recovery
Re
sis
tan
ce
(m
-1)
w/ w/o vibrationBrackish solution
inlet outlet
S1S2S3S4
w/o Vibration
w/ Vibration
Higher Shear
Painted Membrane Tests
Shaded Area
Ring for permeation
5.0
5.1
2,
22Re
2
F
R
Ar
h
rravg
(Jaffrin et al. 2002)
r
A
0 100 200 300 400 5000.0
0.2
0.4
0.6
0.8
1.0
5, 0.6410, 0.32 5, 1.2710, 0.6413, 0.9510, 1.2710, 1.5913, 1.27
Specific Volume (L/m2)
Re
lati
ve
Flu
x (
J/J
0)
R, A
Painted Membrane Tests
Painted Membrane Tests
9.0 9.4 9.8 10.2 10.6 11.0-1.0
-0.8
-0.6
-0.4
-0.2
0.0
f(x) = 0.378849919316468 x − 4.28982761861908R² = 0.96729281987083
ln(γ)
ln(J
/J0
)
0.380/ 0.137 WJ J
Mechanisms to Generate Shear
Membrane Rotation
Ultrasound
Longitudinal Vibration
Shear- fouling relationship
Torsional Vibration
Conclusions
Membrane vibration Increases permeate flux Reduces the contribution of fouling
to the total resistance Changes scale morphology into
more porous structures
Shear Rate Governs fouling of RO
membranes Facilitate the design of similar
systems for fouling prevention/reduction
Acknowledgements
This work was supported by the Water Research Foundation (WRF) *.
The authors thank New Logic Research, Inc., for providing the test unit.
Yujung Chang and Pierre Kwan of HDR, Inc., and Sommer Carter of NLR provided valuable technical assistance during the project.
*The views expressed are those of the authors and do not necessarily reflect those of WRF.
RO Membranes
inlet outlet
0.9 cm
10.0 cm
10.24 cm
Membrane BW-30 FE
MWCO (da) 50 30
MaterialPolyamid
ePolyamid
e
pH 1-12 2-11
Tmax (oC) 70 60
Cl2 Tolerance (mg/L)
<0.1 <0.1
Flux*(L/m2‑h)
71 90
Vendor Filmtec Saehan
*At a TMP of 2068 kPa
Solute Rejections
Brackish solution
Brine
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0
200
400
600
800
1000
0
2000
4000
6000
8000
10000Permeate, w/o vibration
Permeate, w/ vibration
Feed, w/o vibration
Feed, w/ vibration
Recovery
Co
nd
uc
tiv
ity
(u
S/c
m)
Co
nd
uc
tiv
ity
(u
S)
Mg Ca Na Si Cl SO450
60
70
80
90
100 w/o vibration
w/ vibration
Re
jec
tio
n (
%)
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0
600
1200
1800
2400
3000
0
20000
40000
60000
80000Permeate, w/o vibraitonPermeate, w/ vibrationFeed, w/o vibrationFeed, w/ vibration
Recovery
Co
nd
uc
tiv
ity
(u
S/c
m)
Co
nd
uc
tiv
ity
(u
S)
Mg Ca Na Si Cl SO450
60
70
80
90
100 w/o vibration
w/ vibration
Re
jec
tio
n (
%)
Solid Precipitation
EDAX spectrum of scales on the membrane surface
Gypsum
Aragonite
Solid Precipitation - XRD XRD spectrum of precipitates in the feed solution