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

Dr. Mathias Ernst

Zenon

Mitsubishi Rayon

Immersed Membrane Modules (Hollow Fibre)

Puron

Dr. Mathias Ernst

Immersed Membrane Modules (Plate & Frame)

Dr. Mathias Ernst

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

Dr. Mathias Ernst

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°

Dr. Mathias Ernst

t

2

1

Frequent backwash

Irreversibles Fouling

Reversibles Fouling

Flux

Lp membranes flux vs. time

Dr. Mathias Ernst

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

Dr. Mathias Ernst

Proposal of low budget TEX MBR

• Exchange of pumps by hydrostatic pressure• Exchange of polymer membranes by textile materials

Dr. Mathias Ernst

Avantages of textile membranes

Dr. Mathias Ernst

Alternative membranes

Dr. Mathias Ernst

Initial fluxes

Dr. Mathias Ernst

Stationary fluxes

Dr. Mathias Ernst

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

Dr. Mathias Ernst

Labscale MBR system

Non woven membrane

Dr. Mathias Ernst

Labscale MBR Unit in operation

Influent Effluent

Dr. Mathias Ernst

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)

26

Dissolved organic carbon

Dr. Mathias Ernst

Nutrients: Nitrogen and Phosphorus

27

• 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