contributions to permeation resistance in a vsep ro system treating brackish water or brine
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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
ConcentrateFeed
Pump
Feed tank
Amplitude: 13°Frequency: 55HzTMP: 140 psi
RO Feed Composition
Brackish water*
Brine: 10 times as concentrated
pH 8.0 Cl 175Ca 275 as CaCO3 Ba 25Mg 100 as CaCO3 Si 5SO4 350 Fe 0.5Na 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 1.0Recovery
Flux
(L/m
2 -h)
w/ vibrationw/o vibration
Permeate FluxBrine
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
Flux
(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
50000000000000MembraneOsmotic PFoulingCPTotal
Recovery
Res
ista
nce
(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,
22Re2
F
RAr
hr
ravg(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)
Rel
ativ
e Fl
ux (J
/J0)
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 cm10.0 cm
10.24 cm
Membrane BW-30 FEMWCO (da) 50 30
Material Polyamide
Polyamide
pH 1-12 2-11Tmax (oC) 70 60
Cl2 Tolerance (mg/L) <0.1 <0.1Flux*
(L/m2‑h) 71 90Vendor 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 vibrationPermeate, w/ vibrationFeed, w/o vibrationFeed, w/ vibration
Recovery
Con
duct
ivity
(uS/
cm)
Con
duct
ivity
(uS)
Mg Ca Na Si Cl SO450
60
70
80
90
100 w/o vibrationw/ vibration
Rej
ectio
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
Con
duct
ivity
(uS/
cm)
Con
duct
ivity
(uS)
Mg Ca Na Si Cl SO450
60
70
80
90
100 w/o vibrationw/ vibration
Rej
ectio
n (%
)
Solid Precipitation EDAX spectrum of scales on the membrane surface
Gypsum
Aragonite
Solid Precipitation - XRD XRD spectrum of precipitates in the feed solution
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