10-01-2014 Challenge the future

DelftUniversity ofTechnology

Superviser: A/Prof. Bas Heijman

Promotor: Prof. Luuk Rietveld

Ran Shang

Application of Tight Ceramic Ultrafiltration (TCUF) and Ceramic Nanofiltration (CNF)

for water reuse

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Ceramic membranes

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Ceramic membranes

- Homogeneously distributed membrane pores- Long service life- High chemical and thermo- stability Excellence

- High cost (5~10 times) - Fragile Drawback

Defect in a ceramic membrane

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Tight Ceramic UF (CTUF) & Ceramic NF (CNF)

Polymeric membranesCeramic membranes

Relative size of common materials

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Multivalent anion rejection using negatively charged CTUF or CNF

A membrane pore with negative surface

charge

Electrostatic repulsionDouble layer

overlap

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±1Nitrate 1.0±0.5

Conductivity 4.1±0.1Take-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

PS

Municipal wastewater

AS SS

MMF UF RO Demiwaterfor reuse

Digester

Biofouling in RO

Coag. TCUF/CNF

RO Demiwaterfor reuse

>95% P removal~40% OC removal ~60% P removal

~50% OC removal~0,3 µg P L-1

~3 mg L-1 TOC

P limitation!!Low organic carbon!!

Poor removal of OC, P

Biofouling

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Implication(2) for sewer mining

PS

Municipal wastewater

AS SS

MMF UF RO Demiwaterfor reuse

Digester

CNF RO Demiwaterfor reuse

Digester

Energy

Energy

Energy

Struvite

P limitationAnaerobic RO

Biofouling???

Municipal wastewater

PS

Efficiency in concentrating OC and P ???

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Thank you for your attention!