The FT-30 seawater reverse osmosis membrane--element test results

Desaiinatbn. 38 (1981) 473-483 Elsevier Scientific Publishing Company, Amsterdam - printed in The Netherkwds

THE

FT-30

R-E.

SEAWATER

LARSON,

FilmTec

REVERSE

J.E.

OSEIOSIS

CADOTTE,

Ccrporation,

and

15305

MEXBRANE--ELE?lE?JT

R.J.

TEST

473

RESDLTS

PETERSEX

Minnetonka

Blvd.,

Hinnetonka.

M;-nnesota

55343

ABSTRACT A thin-film provides

excellent

membrane, salt

composite

performance

designated

FT-30,

rejection,

chamical

it is resistant

to some

resistant after

to 2,500

chlorine.

chlorine

99.5

Some

hours

with

decline been two

and of

below

usually

years

no

and

to seawater

the at

membrane

carried

have been

in salt with

as

resistance.

membrane

This flux,

In addition,

it is not have

milligrams

operate

that

systems. areas

although

0.5

can

out

loss

at

the

systems,

shown per

fully damage

liter

continuously

been

obtained

rejection

systems

OWRT

salt

in continuous

compaction

seawater

serious

seawater

agents, from

developed

in such

microbiological

in seawater

have

associated in small

with

performance

been

(mg/l

at active

0.2 mgfl.

of 23 gfd

elements

no deterioration

installed

in single-pass

the

were

trials

fluxes

the

used

fabricated

that

has

superior

exposure

studies

In actual

percent

25°C.

hours

It appears

(RO) membrane

disinfectant

elements

long-term

Facilities.

when gives

stability,

concentrations

Several

osmosis

oxidizing

to chlorine;

2,000

active

reverse

and

and with

Urightsville

rejections

when

tested

operation with

only

high psi

over

4,000

the normal

intermittant

FT-30,

has

and

flux

elements

normal

Test

as

at 800

for

Other

scaling.

Beach

as

use

have for almost

in performance.

IhXRODUCTION A new

thin-film

composite

provides

excellent

results

membrane

is noncellulosic

coating

on a microporous

significant

improvement

commercial

thin-film

stability,

and

erties

and

determine

is formed

polysulfone over

rejection

of desalting

support

in terms resistance.

characteristics for use

of

flux,

The

the

of

membrane

in single-pass

FT-30

acetate salt

Because

developed

was

seawater

membrane

types

and

polymer is a

other

chemical

excellent first

new

thin

rejection, its

which

This

a proprietary

layer.

cellulose

been

applications.

by depositing

conventional

composites

suitability

called

in a variety and

microbiological

salt its

membrane.

flow

tested

desalting

prop-

to

applications.

LAFLSON ET AL

474

laboratory test c using

Extensive performed

in a closed-loop

inzrinsic

performance

in fact tests

suitable

were

On

basis

production

lengths

small up

the

and

of

were and

are

test

data

425

tube

and of

a salt total

length

Some

at

area

500

to 900

of

is was

these

element

was

capable

product-water

test

of

tube

can

the

was

results

second

initiated

single-pass

year in

seawater

were

which

of

reported

in

tests

Beach

be cleaned

with

under

both

Test

acid

elements

that

of

Long-term

Facilities of and

its

caustic

this

elezants. in the

is capable

field of

conditions

have

been

high

for

carried

equipment

stability, at

level

as various

by original

cleaners

feet. of 26 gfd

of greater

been

feedwater

chemical

are

is probably

in the have

tests

and

good

provide

as well

the membrane

a variety

a flus

This

imperfections

that

elements

rejection

seawater

over at 800

a product-nater-

with

in flus.

These

is about

of 28 square

that

a salt

in systems

indicate

Because

area

24 gfd

quality

SK31)-4021

obtained,

1.

of 21-inches,

obtained

of

of 4-inches,

give

small

operation.

the world.

two

length were

systems

In-house

in Figure

a flux water

routinely

desalting

tube Data

product

capabil-

to 21-inches

day-.

shokn

feet.

in the

used

per

water

up

produced

seawater

indicate

reduction

components

performance

being

are

membrane 1 were

usually

to seal

now

production

elements,

gallons

for

Seawater

been

Urightsville

around

The

effective

tend

intermittent

data

data

significant

These

years.

are

a diameter

in Figure

have

elements,

larger

10 square

have

percent.

ionic

of

elements

These

Similar

conditions

any

elements

single-pass

the OKRT

for

a product

percent.

an

98.6

small

to 10,000

have

psi.

elements and

of

without

years

both

during

effort

in single-pass

up

of about

solids.

to those

under

two

program

These

the

S1!30-2521

of 98.7

These

s;niiar

these

manufacturers necbrane

of

particles of

to two

facility

with

testing

elements

in diameter,

the different

for almost

cut

inches

rejection

maintaining up

This

testing

fabrication

capabilities

rejection

99 percent

colloidal

the

that

a pilot-scale

in diameter

with

the

the world

flow

of 21-inches,

of

results

throughout

2.

performance

because

results,

applications.

These

dissolved

quite

a salt

than

test

tested

in diameter.

membrane

range

in Figure

Results

results

intensive

were

trr'orepresentative 2.5

effective

ppm

shokn

The

constructed.

an

elements

to allow

used

fur

and

desalting.

in-house

effort,

promising

water

are

2 pressure psi,

suggested

3.

the

being

product

an

to determine

and

to 2.5 inches

up

The

increased

with

an?

and

helped

1.

coupon

designed

tests

the membrane

in Reference

brackish-water

4-inches

elements

These of

seavater

to a comprehensive

2 and

Because

end

was

facilities.

References

long

pass

successful

development

desalination

itfes

system.

to 14-inches.

FT-30

outside

the

elements

In addition of

single in detail

of

facility

producing

test

characteristics

for

reported

the

small coupon samples of the material were

the

temperatures.

z 8

Fig.

24

32

40

0

2400

c

I

1

700 600 900 PRESSURE (PSI1 FT-30 element performance ~8 n function .~ _ of pressure (2.5-inch clcmente)

600

SW30-2521 Elements

1.

500

-

-Id

Feed - 3 2% NaCl pH - 7 Recovery - 2% Temperature - 25“C

99

2

;

z::

Pig.

2.

SW30-402

500

48

1600

2400

100

e

5:

700

function

-Q------e

800

1

900

1

performance as a of pressure (4-inch elements)

PRESSURE IPSII

FT-30 element

600

1

I

I

X-2

Recovery pH 7 - 5% Temperature - 25°C

Feed- - 3.2% NaCl

L

2 VI

476

LARSON

In

several

accidents

flu:; and

rejection

A production diameter for

the nenbrane

custoner

under

evaluations

of

oui

during

and

at govemmmt

the

the

the

year

test

facilities

OF TtiE FT-3C

Descriotion

Yeinbmne

of

of

'T-30

the

nezbrane

t!xree layers:

of

on

FT-30

barrier

both

to 8-inches will

elements

that

original

the

in

be available

It is anticipated

be available

by various

is preser,ted

up

long

1981.

will

that

by mid-1982. have

been

equipment

in this

report.

reverse

osnosis

carried

manufacturers,

:!EIBR_Y;C

is a thin-film-composite

a pol:;ester

ar?d an Lltrzthi?.

sumer

and

operation.

elenents

4?-inches

elements

tests

in the water

cleaning

long

elements

by FilnTec,

CI!EI.IICAL STASILITY

The

a detergent

late

large of

to oil

42-inch

test

during

of

results

past

with

to produce \<;a)' and

quantities

X sumar:;

restored

facility

is well

comercial

were

leas exposed

AL

m

support

coating

on

web,

a nicroporous

t'nc top

surface.

membrane

polysulfone

A schematic

consisting

interlayer,

diagram

of

the

50 Micrometers

I

-POLYESTER

3.

Fig.

Thin-filr_

Structural ei:her

less

a hard. far

significant Cdel

support

vro.,en, such

to produce the

too

is provided

smooth

porous

by

free

to support Instead, onto

ir. that

325 angstrons.

the

sailcloth,

surface

is cast

is rerzarkable

approsixately

cenbrane.

as a Dacron

pressuri.

zolysulfone,

coating

composite

the

of

polyester

or nonwoven. loose

surface

it has

fibers.

ultrathin

a nicroporous the

*Jeb.

surface

barrier

layer of

:he pores

This The

material

webs

must

These

webs

layer

films

are

of an engineering

polyester controlled

web.

can

The

be

be calendered never-

to any plastic, polysulfone

to a diameter

of

LARSO?I

ET &

477

The FT-30 barrier layer is deposited on the surface Of the polysulfone layer. The

barrier

layer

the microporous barrier rates

layer while

Stability

is only

around

polysulfone is optimized

effectively

Under

pH

3500

layer, at

this

stopping

such,

it h2s

is generally can

acid

at

room

studies

change over

and

in nenbrane

found, over

at

of

vater

permeation

baths

of other

depending

beyond

plating

crosslinked

this

at

pH 13,

FT-30

upon

range,

the

and

for

polyamide.

polyamides,

degrada:ion.

3 to 11;

pIl levels

studied

50°C.

found

At

surprisingly of 3-8.6

The

that

performance

pl! range

to those

to chemical

range

at

recently

of Z-10.

although, the

by

The

but

membranes

separations

has

been

example,

2nd

used under

pD 2.

4)

It was

a pli range

supported

pressures.

for maximum

is a proprietary

similar

resistance

a pH

at

(ref.

others.

membrane

on cyanide

conditions

temperature

several

over

be operated

\IcCray et al

to allow

properly

high

passage.

reactivities

in its

routinely

ir.short-term strong

chemical

it can

but,

very

Extremes

superior

be used

required,

thick

withstand

thickness

salt

The barrier layer in the FT-30 Xs

angstroms

it can

at

the

FT-30 room

effects

of

"T-30

after

again

no

FT-30

membrane

the

at

~2s

studied there

temperature,

50°C

while

of pE on membrane

membrane

approximately

significant

pli 2 2nd

was

showed

10 there

no

three

change

performance

along

with

significant

weeks

exposure

in performance

2 slight

leas no

decrease

7~~s in flu:;

significant

change

in flux.

Siocidal

Protection

Various elements for

stornge

to determine

storage

AC

this

growth.

appears

with

generally

chloramine-T but

their

rather with

this

the

and

conducted

biocidal

sodium

ma%ntains

small

increases

chlorinating The

S-cWhloroisocy2nurates, properties

to chlorine The

reagent. of

FT-30

these

are

(0.1

bisulfite

such

salt

that

not

very

but

not

membrane

is permeable will

great.

pass

procedure sodium

in eliminating

f1.1~ during

storage

rejection.

these

enough

menbrane

best

aqueous

membrane

within

is resistant

dioxide,

disinfectants

The

percent)

be practiced

membrane

spiral

is effective

initial

can

on FT-30

procedures.

ppm

in membrane

agents FT-30

FilnTec

protection

This

treatment

at

in a 1000

concentration,

disinfectant

Either

been

element

recommended.

resistant

dioxide.

have

optimum

to promote

Disinfection not

DisinfectXon

is to soak

bisulfite. biologic21 and

and tests

mild The

agents

but

c2n

membrane

experience to chloramine

through

limits,

is

to chloramine, be used,

is also

has

been

and

gained

to chlorine

the membrane

into

the

permeate. The attack

membrane

has

is dependent

only

limited

on pH and

resistance

salinity

to free

levels.

The

chlorine. chlorine

The attack

rate

of chlorine

is most

478

IXRSONETAL

rapid

at

lower

seawater. to chlorine

does

not

where

to a chlorine

residual.

free

can

chlorine

1IcCray et al

iodine,

the

bromine

4) also

indicated

high

the

for

FT-30

iodine

pH,

and

at zny

peroriide.

The

latter

quaternary caused

ten

sulfate

flux

were

slowest

in

be used

effectively

exposure

in

of the membrane

the membrane

system

with

may

the

membrane

to

that

the

FT-30

membrane

is quite

studied

the

effects

These

to halogen most

by halogen The

attack.

but

disinfectants most

showed

and

not

Our

growths.

compounds

The

promising 5.8,

5.8.

temperature

algae

equiv-

indicated

at pH 3 and

formaldehyde

are

to an tests

disinfectants.

to be chlorine

at pH 3 and

of bromine,

exposure

pH levels.

fastest

be used

for

phenolic

FT-30

by continued

reported

at room

be used

the

is affected

dioxide

be used

and

and

of the membrane

of

is exposed

showing

that

can

germicides,

dioxide

menbrane

chlorine

found They

at various

the membrane

disinfectants

Copper

atures.

it was

chlorine

membrane

of

response

attack.

dioxide

it can

in temporary

treatment

the

chlorine

ST-30

chlorine

disinfectants

Alternative

studied

and

of 3 ppn

that

ph with

Thus,

water

exposure

circumstances.

disinfectant

of pl! when

in deionized short-term

result

shock

in some

chloride,

importance

may

In general,

to halogen

concentration

data at

(ref.

that

the membrane. upsets

In fact,

disinfectants.

resrstant

alent

system

be used

fastest

however,

destroy

installations

halogen

occurring

salinities,

It is noteworthy,

hydrogen

at elevated

tests

with

temper-

iodine,

all of these agents

that

losses.

Cleanabilitv Because

of

and

could

FT-30

with

not

out

alkaline

be

cleaning,

can

cleaners,

and,

detergents membrane

various

elements;

used

sparingly

a tendency losses cleaning

and

encountered

solutions

lauryl which

sodium can

sulfate

FT-30

membrane,

FT-30

elements

nonionic

which

be used

with

removal,

acids

use.

greatly were

surfactants.

would

that

sodium

with

a liquid

EDTA

(ethylene-

and

these

sodium

alkaline

Commercial flux

reducing

flux.

Major

to 800

in

Wisk.

but must

surfactants

at 200

laundry

declines

detergent,

processes,

with

For

Nonionic

exposed

requires

is best

at pH 2.

temporary

cleaning

alkaline

in 30 minutes

scale

as

Both

The

cycle

tripolyphosphate,

cause

after

the

effectively.

membrane,

such

temperature

to 50°C.

is recommended.

obtained

out

and

a cleaning

nitric

of agents

when

containing

and

in membrane

rinsed

very

be accomplished

generally

were

be used

acetate

for mineral

surfactants

results

can

thoroughly

to plasticize

were

as

out

temperatures

example,

can

phosphate,

sodium

best

at

for

combinations

ingredients

detergents

such

stability

be carried

of phosphoric

Anionic

of pH

by cellulose

nenbrcnes

trisodium

in fact,

can

tolerated

processing,

cleaning,

be used.

contain

Xonionic

are

a cocbinetion

diiininetetracetate). carbonate

membrane

acetate

Acid

with

combination

tolerated

whey

cellulose

membranes.

carried

this

cleaners

In cheese

hydrolyze.

membrane's

of

alkaline

conditions

4 hours

FT-30

cleaning

resistance, acidic

the

psi

be

have flux

to

LFBSONETAC

473

ELEXENT

TESTS

During out

CONDUCTED

the

past

by various

Various of

BY OTHERS

two

years

original

operating

feedwaters,

many

systems

and

including

seawater,

solutions

were

sold

installed

in operating

and

both

to a variety

in this

operating and

country

decline

Several

Test

using

tests

vere

solids

tern

to determine

test

performed in Figure

and

the

for

a rejection

remained rejection

The

were

dropped

chlorination It

thet

trisodium

phosphate

flux

decltie

about

2,000

by an

Increase

appears

then hours

to take

continuing the

rapid permeate

the

400

dropped

continuous 7.5

gfd

were

are

also

to the

was

the

started

sudden

earlier

by

the

the

initial

and

an

tests

was

900

elements results out

hours,

ppm, the

The

15

400

the

flux

are

at

ppm.

flux

resulting

hours.

in a

started permeate

carried

out

passage.

its

flux

in salt

The to 1900

initial

damage

tests ppm.

then were

of

organic

constant

membrane

as evidenced at

with

A rapid

vaftle.

terminated

Beach.

a cleaning

appeared

The on,

was

immediately

other

After

remained

passage.

from

at au flux

initiation

and

surface. to

and

conditions

at Wrightsville

of bacteria

The

initial

hours

after

test

chlorine

The

300

The

5.

4 except feed.

of chlorine

rate

at the Wrightsvilla

in flux

restored

hours.

signs

increase

increased

the

A long-

of about

operating

at about

the membrane

increasing

in salt

drop

destruction

on

flux

test

5.6.

started

in Figure

in Figure

THIS had

rejectior

total

the

content

determined

presented

data

to deposit

flux

at 2,700

added

in some

of

operation,

the

This

Beach

is about

to 200

was

when

rise

about

had

pi

(TDS)

for

an

continuous salt

an average

in series;

ppm

at

under

ppm.

feed data

until

place

out

been

locations,

long-term

characteristics

solids

At

has

the

elements,

TDS

400

occurred

in flux

and

as

(TSP)

been

the

feed

elements

dissolved

With

chlorination

tend

have

different

OIJRT Wrightsville

of 0.5

to be caused

then

ppm,

of about

These

the This

operating

permeate

to about

noted

at

particular

percent.

same

elements

carried

S\130-25X&

a total

to 8 gfd.

was

is thought

growth

after

the

23 gfdflux

the

of a chlorinated

the

sodium have

tests

were

percent

a variety

that

at 20

feed.

baseline

a value

concentration

FT-30

and

elements

conditions

to determine

out

518.8 percent.

Pacilities.

3.5

laboratorier

elements.

of 32,000

of

the

99.4

reached

essentially

about

but

increased

effects

average

the

and

Test

carried

these

had

of about

of about

content

Beach

For

constant,

to decline salt

4.

permeate

the

seawater

the

three

hours

of

concentration

using

gfd

Several

4,000

and

carrit

been

test

involved,

numerous 200

have

and

Facility

a pretreated

dissolved

shown

over

Beach

long-term

facility

was

abroad.

for

were

seawater

over

test

elements

consultants,

to the

equipment,

and

membrane

facilities

synthetic

In addition

characteristics

Wrightsville

FT-30

test

of controlled

conditions

flux

OWRT

used.

of

manufacturers,

special

chloride

subjected

tests

equipment

until

as evidenced damage by 3,100

the hours

LARSON

480

z 2

EXAL

Feed -Seawater (320OOtJPm) pH - 5.6 Pressure - 8OOpsi Flux Corrected to 2.VC Recovery - 5%

600

1

I

I

I

1 &!/f-l Data are Average of Three SW30-2514 Elements

j G

400

I

I

800

1200 1600 2000 OPERATING TIME (HOURS)

Fig. L,. FT-30 eleflent perfomance Beach Test Fncifitv. U.S. 2000

under DsDEZrtnent

2400

2800

3200

long-ten;? test on seawater at Vrightsville of the Interior.

pi-l - 5.8

_ Average ChlortneConcentration during Exposure - .5ppm

OPERATING Fig.

5.

FT-30 element seawztcr

Interior,

perfornance

at Erightsville

under

TIME (HOURS) long-term

test

(chlorine

feed

.5ppm)

Beach Test Facility, U.S. Department of the

GE

LARSON

ET

461

AL

experiment

The

which The

was flux

After

was

added

at

started

a steady

hours.

This

quickly until

flux

followed

98.5

percent

damage

fell after

is probably

observed.

The

of degradation

lOOr

a reduced

of

run.

start

decline

flux

to about only taking

place

with

95 1600r

then

the

results

is strongly

restored

are

TSP

not

at 500

This held the

came

suggests

caustic,

in Figure

with

which

ppm,

percent.

value.

however,

This

0.3

flux,

back

that

wzs steady but

Eo about

chlorine

inrmediately

acelerated

the

rate

membrane_

I

I

I

1

I

I

I

I

I

I

1

---rF-l

98

96

TSP

99.3

cleaned

original

Rejection,

though

which

99

97

with

of

presented at

to 11 gfd,

of operation.

even

TSP,

were

to the

however,

percent.

are

rejection

elements

cleaning

hours

results

salt

in flux

decline,

95.5

a few

the

the

concentration

cVhlorine These

and

increase

Another

hours.

the

the

18 gfd

to 7 gfd,

in an

cleaning of

using

at about

by another

1,800

rejection

the

out

resul:ed

about

the

repeated

14

4

Feed - Seawater pH-55 Average Chlorme

(32000ppmI

-

Concentration - .3ppm Pressure - 8OOpsi Flux Corrected to 25% Average Recovery - 5%

Data are Average of Three SW30-25 14 Elements

.

“0

Fig. on

6.

400

FT-30

seawater

800 OPERATING

element

1600

1200

2000

TIME tHOlJRS1

performance

at Krightsville

i-

Beach

under Test

long-term

Facility,

test U.S.

(chlorine

Department

feed of

the

.3 ppm) Interior.

6.

LARSON

482

Various

Short-Tern

salt

in the

table

can

seen

of

be

2.2 gfd

from

2 10~

about retains

have

corrected

that

salt

cleaning

trials

have

been

give

shown

that

are

flux

a low

percent,

results

under

14 gfd

rejection

an average

a variety

of

because

test

be

It

to a high varies

value

FT-30

of

membrane

conditions.

of scaling,

can

shown

effects.

salt

the

3.5

data

The

that

properties

and

flux

of about

with

indicate

decreases

seawater The

temperature

18 gfd.

the nembrane

neani

in several

test

sane

product

results

(P?ESSUEE

O:‘R?

of 99.8

and

water

L!lC.tiICFi

!e

applications.

indicate

that

elements

flus

salt

rejection.

= 200

and

PT-30 Jai,

ELE9ENT

'Zrlghtsvil

to be representative

hundred

RCPRESESTATIVE

TEZi

from

characteristics

increases

table

other

:he

varies

on

table.

to minimize

of around

the

tests

following

repeated

restored

with

TYPE

s:;30-251L

ELEXEXT

TESTS

Aecoyery

LZ.

only, These

but

data,

of various

REPORTED

sties

Seawater

appear

to

to 25 C)

PRODUCi rlATER FLUX (gfdl 18

results

with

BY OTHERS

~IG.JS corrected

FEEDdATER

similar along

SALT' AEJECTIOI~ 99.3

Rrach Test

Fncilicv

California.

OE?! til

s1:30-2514

Sea*
17

99.8

CaLiEornia.

OEN

SW30-2521

Seawater

20

99.2

=I

Eng!anc,

021 72

s:i30--514 L

Syn.

Seawater

14

99.0

England.

OEY

Seawater

&2

SW30-4014

Syn.

16

99.0

California,

OE>l $3

sw30-2514

3.57' 0 YaCl L

15

99.0

California,

OEM

~4

SW30-2514

Seawater

18

99.0

California.

OEN

=L

SW30-2521

Seawater

22

99.0

OEW

,:&

SW30-4021

Seawater

21

99.0

California, FlorIda,

OE!I 25

SW30-2514

3.52

NaCl

21

99.1

FLorida.

OEN

Sh'30-2521

3.5%

NaCl

22

99.1

England,

OEt-I=6

SWjC-2514

SC?ZlWaCeK

IL

99.2

Sr:itterland, Texas,

,=5

OElY +T

OE?! -L8

Louisiana.

CD1

a

procedure.

in the

cbtained

nurercus

to a high

rejec:ion

have

cleaning data

flus

value

In general,

passage

in the

to 25°C

the

an average

99 percent

salt

The

in general

with

Although

proper

been

percent.

its

of high-osmotic-pressure

is presented

of

99-i

listing

solutions

and

AL

Tests

A representative percent

ET

-79

SW30-2514

SyII. Seawater

14

99.0

SW30-4021

Seawater

20

99.0

SW30-4021

Seawater

20

99.0

f

LARSONFPAL

483

CONCLUSIONS

During and

the

past

spiral-vrap

locations

tion. The

of

is capable

have by

been

range

of pH

oxidizing other with

of

FT-30

from

thaat the

in a "real

acid

with

world"

the use

technical

have

been

passage

and

have

with

the

reverse

field

flow

of long

dura-

been

all

performed. membrane

the vagaries by end

osmosis

for about

or low

of

composite

systems

test

a variety

been

have

membrane

at various

with

thin-film

seawater

of

in the

salt

some

environment,

knowledge

of high

in-house

operations ET-30

of FT-30

performed

and

of small

in use

program

both been

of pretreatment of cleaning

because

twc

process. years

other

and

users,

than

and as

few

caused

elements. is chemically

3-11.

Although

such

as chlorine,

polyamide-type both

have

number

membrane

agents

out,

tests

indicate

little

the

carried

These

testing

tests

elements

returned

fouling The

have

been

extensive

a large

these

associated

FT-30

an

degrees

of operation

of whom

The

has

world.

various

In addition,

uncertainties many

the

with

results

years.

elements

around

feedwaters

three

and

membranes

stable

and

it is not

caustic-type

are

be operated

impervious

it shows

that

can

cxnmercially

cleaners

to attack

considerably

to remove

more

over

a broad

by various resistance

available.

It can

metal

oxide

scale

small

elements,

and

than be cleaned organic

foulants. On

the

production in diameter

basis

of

facility will

the

successful

is now

being

be available

results installed

within

with and

the

42-inch

elements

up

a large

element

to S-inches

a year.

REFERENCES 1 Cadotte, J-E., R.J. Petersen, R.E. Larson, and E.E. Erickson, "A New Thin-Film Composite Seawater Reverse Osmosis Xembrane" Desalination, 32, (1980) 25-31. "Development of the FT-30 Thin2 Larson, R-E., J.E. Cadotte, and R.J. Petersen, Film Composite hfembrane for Seawater Desalting Applications" XWSIA Journal, 1981) 15-25. 8, >!o. 1. (January "Development of the FT-30 Thin3 Larson, R-E., 3-E. Cadotte, and R.J. Petersen, Film Composite Xembrane fcr Brackish Water Desalting Applications" NIJSIA Ninth Annual Conferences and Trade Fair, (Yay 31-June 4, 1981). on 4 %!cCray S-E., J. Glater, and J-W. YcCutchan * "The Effect of pH and Halogens University of California, Los rhe Stability of Reverse Osmosis Membranes", Angeles. UCLA-ENG-Ell5, WRC 73 (July 1981).