Transcript and Ceramic Nanofiltration (CNF)

Ran Shang
Superviser: A/Prof. Bas Heijman
Promotor:
Delft
University of
Technology
Challenge the future
Prof. Luuk Rietveld
10-01-2014
Ceramic membranes
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Ceramic membranes
Defect in a
ceramic
membrane
- Homogeneously distributed membrane pores
- Long service life
- High chemical and thermo- stability
Excellence
- High cost (5~10 times)
- Fragile
Drawback
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Tight Ceramic UF (CTUF) &
Ceramic NF (CNF)
Relative size of
common materials
Polymeric membranes
Ceramic membranes
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Multivalent anion rejection using
negatively charged CTUF or CNF
Double layer overlap
A membrane pore with
negative surface charge
Electrostatic repulsion
Cations >> anions
Take-home message:
• 40%~87% of Ortho-P rejection by a 3 kDa TCUF, dependent on
operational conditions (flux, cross-flow velocity, pH).
• Higher solution pH leads to higher rejection, due to enhanced negative
surface charge.
(Shang et al. Wat. Res. V. 48 P. 498-507)
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Secondary effluent water filtration
using 3kDa TCUF
Rejections, %
Organic matter
45±3 in DOC
61±2 in UV254
Phosphate
62±7
Sulphate
16±1
Nitrate
1.0±0.5
Conductivity
4.1±0.1
Take-home message:
• Phosphate has negative charge and low diffusion: thus easy removal.
• Membrane fouling by effluent organic matter can enhance phosphate
rejection.
• About 50% or higher organic removal.
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Implication(1) for effluent water reuse
Municipal wastewater
PS
AS
Digester
SS
MMF
UF
RO
Demiwater
for reuse
Coag.
TCUF
/CNF
RO
Demiwater
for reuse
>95% P removal
~40% OC removal
~60% P removal
~50% OC removal
P limitation!!
Low organic
carbon!!
~0,3 µg P L-1
~3 mg L-1 TOC
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Implication(2) for sewer mining
Municipal wastewater
AS
PS
SS
Energy
Municipal
wastewater
MMF
UF
RO
Energy
Demiwater
for reuse
Digester
PS
CNF
Digester
RO
Demiwater
for reuse
Anaerobic RO
P limitation
Energy
Struvite
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Thank you for your attention!
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