Removing ammonium ions using electro-deionisation

Research Trends Measurements coefficients

coefficients materials

membranes

of -

(MF:

water

porous

average

0.8 and 8.0 pm) and ceramic

(CM:

average

pore

size of 4.4

as a function

relationship

NMR

between and

the

determined

by scanning

was examined. MF0.8

to

depend

this

affected

not but

membrane

matrix

Nitta,

the

the

pore

matrix.

>

the

membrane

during

the

predicting

by

an

Desalination 123(l)

Tanioka:

9-14 (30 August

desalt

water

water

Desalination

of surface water

treatment

total water

stage with

partial

membrane

without

using

retentates

that

this by

(MPRO)

(EDR),

thus gaining

matter,

fouling

was or

stage or

and

for

definitely

the

used to desalinate indicate

to desalinate

humic from

organic

substances,

are

a raw feed-water river

water

can be

H. Chmiel,

Desalination

123(l)

B. Heitele,

33-43

F. Riigener:

(30 August

Membranes

have

sought-after

in membrane

interest

low levels (less than ions,

which

effluent

200 ppm)

streams

in such diverse

expected

in a space

station

fisheries.

Ammonium

ions

decomposition

product

techniques

build

rendering

up the

in

unsuitable for

are used in various

such

as desalination,

great

treatment

degree

of

development of

which

membranes.

mitigation effort

by several

problems. around

@

water

purification

plants.

There

has been a

the

two-stage

simulated stage

aqueous

unit,

reduced

from

The volume

waste

200

the

over a 24 h period.

fouling

to solve fouling groups

from

of which

Whllb

treatment

(2.3 Whlkg)

lb of water

ppm

a

thus

by applying

team

Electrical was

for

based

a

a two-

could

be

1 ppm. kg) of

consumption to

be

on processing

for 5.04 225

Gaspar,

D.J. Helden, H.

H.V.

Zanapalidou:

Desalination 123(l) 85-92 (30 August

had under-

The Pitzer

calibrated

for RO

K,,

an experimental at a temperature

for the ionic strength ionic strengths, The

of

range O.Ol-O.lM.

the Pitzer model

observed

stable

(27 times the solubility and is under M.D.

was

super-

at 5°C) in the

is most likely caused

S.F.E. Boerlage,

by the low rate

investigation.

Kennedy,

G.J. Witkamp,

1999).

membrane contactor

contactors

is a device that achieves

or liquid/liquid

mass transfer

of one phase within

accomplished

by passing

another.

the fluids

sides of a microporous

membrane.

control

of the pressure

difference

fluids,

one of the fluids is located

so that

advantages

over conventional including

the

in the

of each pore. of important

dispersed-phase

the absence

of emulsions,

at high flow rates, no unloading

low flow rates,

no density

fluids is required, interfacial

By careful

the fluid/fluid

a number

contactors,

This is

between

at the mouth

offers

without

on opposite

is immobilised

of the membrane approach

difference

and surprisingly

area. Membrane

at

between

there is a high

contactors

typically

offer 30 times more area than what is achievable in

gas

absorbers,

obtainable leading geometries tube-side hand,

500 low of

are possible, mass

the most transfer

with reasonable

shell-side

times

coefficients

what

extraction

remarkably a number

received

predicted

and

in liquid/liquid to

Although have

per day. D.J.

30%.

when

prediction

no flooding

to be recycled

found

confirmed

that “organic?

of precipitation,

This

using

on 225 lb (102

matter)

by about

concentrates

accurate.

Seeded

and synthetic

Du Porn’s method

solubility

interface

was evaluated Using

organic

methods,

pores

wildlife.

to less than

E.F. Spiegel, EM. Thompson, Doan,

human

was evaluated

stream.

for a four-person ED1

as a

for

system

models.

of barium

and Bromley

dispersion as

over

ion content

was based

but

the

ED1

ammonium

water

on

members

a

Pitzer

and proved

Hollow-fibre

of the low concentrations

ions. The process

the

held as a joint

various

using

(EDI)

because

in

is the fouling

workshop was recently

organisations

world,

and

systems,

still remains

It attracted the

and plants

advancement

A

processes

processes.

industries

of membrane

“bottleneck”

most

(no

gas/liquid

and

supporting

and

determination

A membrane

commercial

are generated

concentration,

water and

this process

of the

in separation

They

waste-water

one

prediction,

of

applications

of urea,

the

to solubility

of

in recycled

and

in RO and

ofMembrane Science 159(1-2) 47;59 (1 July 1999).

of ammonium

found

on

study

J.I? van der Hoek, J.C. Schippers:/.

for the removal

are commonly

BaS04

effects

This

solubility

approaches

as Bromley

saturation

ions using

system

of

theoretical

For higher

1999).

rate matter

using more

more

A. Mesri:

exists for the development

an electrodialysis

of ammonium

become

and 47%,

M. Safar, S. Ebrahim,

consumption

1999).

42%

Desalination 123(l) 71-78 (30 August

Electra-deionisation

Fouling mitigation processes

96%,

and total

at the

are: inaccurate

for example,

pilot plant

Y. Al-Wazzan,

time

obtained. V. Mavrov,

were 99%,

barium

5-25°C

The

BOD

predicted 14 times at

precipitation.

gave accurate

respectively.

Current

yield and

by dissolved

COD,

operating

effect of ionic strength,

predicted

is a viable

this type of water.

in TDS,

investigated

organic

no effect on solubility.

water.

RO

or

super-saturation

sub-surface

that

solubility

concentrates

for the

an

method

a low

and/or

the

data

of on

and yet no scaling occurred

has

2200

method is based

was exceeded

prediction;

growth

to desalinate

to

This

Possible explanations

precipitation

such

colloidal

discusses

of performance

reverse reversal

product

so that

of up to 98%

be

reduce

Research

work

further

The

pressure

This

RO plant

values

of

to

to assess the economic

hours

results

extent

Therefore,

Scientific

of using RO technology water.

RO

and

feed-water. for

in

the

used

fouling

operating The

of

the

be

Removing ammonium electro-deionisation

biocides.

reuse. Scaling caused

fouling

example

prevented

can

a higher

prevented

stage

electrodialysis

for concentrate

by silicates

of the

osmosis

medium

osmosis possibilities

operation

on must

a project

sub-surface

to

but its use with

reliability

biological Institute

count in the pre-

reverse

inhibitors

of

concentrated

yield

alkaline

desalination

(LPRO),

softening

The

depends

in

used

(RO) severe

in RO concentrates,

limited

solubility

solubility

being

has not been investigated

before.

technology

is now

of feed-waters,

improvement By combining

that barium

RO system

(RO)

a variety

technique

1999).

45-53

80% recovery

osmosis

feasibility

A.

123(l)

Pant’s which

solubility

of 25°C.

osmosis

potentially

Du

and

in RO

in reverse and

scale,

barium

is unreliable temperature

Desalination

scaling decline

damage.

predicting

in this area.

Sub-surface

coefficient

the

updated

and the future

1999).

implemented

is

to provide

activities

prediction

BaSO,

pilot plant.

Kuwait

in

it aims

(current

(30 August

materials

increase

Natsuisaka,

and

work required)

diffusion

size.

M.

workshop,

suspended,

pore

sulfate flux

reviews

size

in the

Barium

work

was set. This which

directions

causes

was presented

area

pretreatment

and

were discussed,

in this

Results show

by a decrease

also

of MF8 by Tanner.

in the diffusion

only

diameter K.

theory, on

techniques

BaSO, solubility systems

and

bio-fouling.

research

Kuwait

water

in this

desalting

and possible

and ongoing

sub-surface

microscopy, of the

theory

of the membrane

that the decrease

as

covered

and a “road map” for future

Reverse

These were explained

diffusion

coefficients

The

structure,

is in the order

According

were

diffusion

electron

> CM > MF0.025.

-

water

magnitude

coefficient

thickness

inorganic

recent initiatives

mostly

R. Sheikholeslami:

time using

membrane

The

by the restricted

pm)

(PFG-NMR).

the

coefficient

diffusion

associated

information

membrane

of diffusion

field gradient

in

cellulose

pore sizes of

0.025,

pulsed

topics

information

Self-diffusion

measured

and discussed

Recent

of self-diffusion

inhomogeneous acetate

presented area. The

HTU

membrane hollow-fibre

attention.

values. module modules

In general,

coefficients accuracy.

is

columns,

can

be

On the other

are more difficult

to

Membrane Technology No. 119