Textile membranes systems as a simple approach to apply ... · Textile membranes systems as a...
Transcript of Textile membranes systems as a simple approach to apply ... · Textile membranes systems as a...
Dr. Mathias Ernst
Dr. Mathias Ernst, TU BerlinCentre for Water in Urban Areas
Textile membranes systems as a simple approach to apply reclaimed water for safe reuse application
Dr. Mathias Ernst
decentralised and low cost ww treatment for safe reclamation in irrigation
(i) Sanitation(ii) increase availability of recycling water MDG 7
Objectives
Dr. Mathias Ernst
Conventional and MBR ww treatment
screen
influent
sand grid settler biological reactor settler
effluent
air
excess sludge
sand-filtration
dis-infection
Modular and flexible Decentral plants Physical disinfection
Conventional WWTP
biological reactor
air
excess sludge
effluent
influent
screen sand grid
MBR WWTP
Dr. Mathias Ernst
Lp membranes in wastewater treatment:
c1c2
Jw
Js
Concept of fluxJw = k ∆p
k [ l / (m2 h bar)]
Dr. Mathias Ernst
Pseudomonas Diminuta0,28 m
Reverseosmosis
Nano-filtration
Ultra-filtration
Micro-filtration
0,0001m
0,001m
0,01m
0,1m
1m
10m
100 m
.
diameter of membrane pores
Streptococcus1 m
Influenza virus0,1 m
Haemoglobin0,007 m
Sodium-Ion 0,00037 m
water
0,0002
m
Giardia Lamblia and
Cryptosporidium3 à 6 m
Retention of SubstancesNematodes
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Zenon
Mitsubishi Rayon
Immersed Membrane Modules (Hollow Fibre)
Puron
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Immersed Membrane Modules (Plate & Frame)
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Decentralised domestic MBR treatment
Small scale plant BioMIR©:
for 4 to 8 persons
2 to 3 m³ reaktor volume
2.4 to 4.8 m² membrane area
Dr. Mathias Ernst
—CH2—CF2—
O||S||O
o
nPolyethersulphone (PES)
Polyvinylidene fluoride (PVDF)
n
o
oo
o
oH
oAc
CH2oAc
CH2oAc
oH
oAc
Cellulose Acetate (CA)Ac: OCOCH3
n
Inorganic Organic
Ceramic (ZrO2)
Celluloseacetate (CA)
Glass Polyamide (PA)
Metal Polyethersulfone (PES)
Polyvinylidenfluorid (PVDF)
Membrane materials
Prices =50 – 200 € / m2
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Characterization of clean ultrafiltration membranes
Microdyn-Nadir UP 150 Microdyn-Nadir UV 200 MEMCOR
AFM
(5 x 5 µm) (clean(5)#4) (cleanalt(5)#2) (clean(5)#1)
FE-SEM(50 000-fold) (50 000-fold) (50 000-fold)
Type flat-sheet flat-sheet hollow-fiber
Material hydrophilized PES PVDF PVDF
MWCOnominal 150 kg/mol 200 kg/mol no data
Pore size (FE-SEM) 25 - 35 nm 25 - 45 nm 20 - 40 nm
Average roughness 3 1 nm 26 4 nm 46 8 nm
Contact angle 50° 65° 65°
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t
2
1
Frequent backwash
Irreversibles Fouling
Reversibles Fouling
Flux
Lp membranes flux vs. time
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MembranstufeRezirkulationspumpenRührwerkeFeinblasige BelüfterEinlaufpumpwerkAir-cycling
0,12
0,21
0,16
0,88
0,05
1100 2200 3300m³/d0,09
0,14
0,850,7
0,1
0,11
0,69
Anlagendurchsatz
0,9
0,2
0
0,4
0,6
0,8
1
1,2
1,6
kWhm³
s pez
ifisc
her E
ner g
iebe
d arf
1,1
0,92
1,42
Plant capacity [m3/d]
Spe
c. e
nerg
y de
man
d [K
Wh/
m3 ]
MembranePumping StirrerAerationInlet pumpingAir stirring
MBR energy consumption
Economy of scale! < 0,8 kWh/m3
(Gildemeister, 2003)
Conventional treat. 0,21 kWh/m3
(Wursthorn, 1998)
Dr. Mathias Ernst
Standard MBR
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Proposal of low budget TEX MBR
• Exchange of pumps by hydrostatic pressure• Exchange of polymer membranes by textile materials
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Avantages of textile membranes
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Alternative membranes
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Initial fluxes
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Stationary fluxes
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Critical flux phenomena (stainless steel, 10µm)
-1
19
39
0 10 20 30 40Flux [L/m²h]
Gra
dien
t of p
ress
ure
[mba
r/min
]
critical fluxat 12.6 LMH
Dr. Mathias Ernst
Sustainable flux for MBR systems
Dr. Mathias Ernst
• Three reactors: anerobic, anoxic, aerobic• Total Reactorvolume = 1500 ml• Flowrate = 150ml/h → (HRT~ 15h)• Membrane, textile, non-woven, 10µm, flux= 10 lmh
Development of an labscale Tex MBR system
Sediments
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Labscale MBR system
Non woven membrane
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Labscale MBR Unit in operation
Influent Effluent
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PARAMETERINFLUENT
CONCENTRATION MBR [mg/l] (SD)
EFFLUENT CONCENTRATION
MBR [mg/l] (SD)REMOVAL [%] (SD)
CSB (n =24) 299 (± 121) 31.2 (± 8.3) 89 (± 6)
DOC (n =34) 41.6 (± 20.8) 11.5 (± 1.7) 68 (± 10)
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Dissolved organic carbon
Dr. Mathias Ernst
Nutrients: Nitrogen and Phosphorus
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• stable and very good Nitrification• Denitrification around 50%
N P
•Due to difficulties with excess sludge phosphorus removal is only around 30% (incooperation)
Dr. Mathias Ernst
Conclusions Textile membranes can be a substitute for organic polymer
membranes in MBR treatment (by 100x cheaper) Non / woven textile membranes pore diameters > 1 µm.
However the building up of a secondary membranes (EPS, biofouling) may allow good rejection rates for bacteria, protozoa and nematodes (lab scale MBR experiments) The membrane flux through these textiles should not exceed
10 LMH to avoid critical flux phenomena and sustainable operation. With low cost textiles and hydrostatic pressure operation
(reduction of pumps, no backwash), Tex-MBR’s can be a suitable decentralised wastewater treatment and reuse technique for irrigation Textile MBR might be further developed in a
micro business approach