Note: Descriptions are shown in the official language in which they were submitted.
7~
Water softeners and demineralizers filter particulate
matter from feed waters. These partieles and the resins
themselves also absorb naturally oeeurring and synthetic
organic substances sueh as lignins, tannins, humates, oils,
grease, water-soluble or dispersible polyrrers, ete., whieh rnay
be excellent nutrients for bacteria or which may be direct
foulants themselves. As the bacteria mul-tiply, bacterial slime
micro-organisms and waste products thereof can accumulate.
These factors can drastically influence the performance of an
ion exchange ~mit through shorter operating periods before
regeneration, lowered resin capacities and poorer effluent
water qualities. In addition, treated water containing micro-
organisms and their waste products can present health problems,
depending on the use of the water.
It has been found that the combined use of a non-
ionic surfaetant and a bio-dispersant ean remove miero-organisms
and waste produets thereof, as well as organie foulants and
oil and grease foulants from ion exehange resins and other
water treatment solids. Tests indicate that a substantial
improvement in water qualities and in ion-exchange resin
eapaeities for both water softener and demineralizer resins are
obtained by eleaning the resins with an effeetive amount of a
non-ionie surfaetant and a bio-dispersant as deseribed below.
A eombination of these non-ionie surfaetants and a bio-disper-
sants can also be used to maintain water-treatment resins in
peak operating conditions by treating resins on a eontinuous
and eyelical basis during the
lZ18~'75
backwash cycle used in the regeneration process. The combined
treating agent also provides a steady removal of organic anions
that severely foul strong base anion exchange resins.
It has also been found that these
surfactant/bio-dispersant combination products may also be
improved by the addition of certain microbiocides.
REVIEr~ OF PROBLE~
Water softeners and demineralizer ion exchange resins
can remove a variety of insoluble substances present in the
feedwater requiring treatment by these resins. These insoluble
substances can include insoluble iron salts, inorganic
precipitates, silt, semicolloidal lignins, tannins, humates,
natural and synthetic polymers, etc., plus oils or grease. These
ion exchange resins and accumulated particles can also adsorb
soluble organic substances. Most of the organic substances
adsorbed on resins will ultimately influence the resin capacity
and leakage rate of an ion exchange unit because of reduced rates
of diffusion of ions into and out of contaminated resin beads.
In addition, the organic substances either adsorbed by
the resin or filtered from the water can be excellent nutrients
for micro-organisms. As these micro-organisms multiply,
microbiological fouling in the ion exchange units does occur.
Resin beads that are already coated with organic substances
become coated with bacterial slime and other micro-organismic
waste products which will further decrease the performance of ion
exchange units. Shorter runs before regeneration and poor
effluent water qualities are the usual observations. Removal of
these contaminant mixtures by inorganic regeneran's alone or with
salt or caustic solutions is not successful.
-3~
~ ~ lZ113475
As the organic foulants, bacteria, bacterial slime, and
waste products continue to accumulate, the formation of large
clumps enveloping large portions of the resin is found in the ion
exchange units. These clumps will still further reduce the
effectiveness of ion exchange units due to bed packing and
channeling which can cause an early leakage of ions, i.e., can
lead to early loss of capacity of these resin units. Field
reports of reduced operating capacities being down to ~5-50~ of
the original capacities are not unusual.
Micro-organisms are found in almost every
water-treatment resin and their presence is not limited to any
specific resin type. It includes water softener resins as well
as cation and anion exchange resins used for the deminerali~ing
of water. Bacteria is also found in home water softeners that
are used on chlorinated water and on industrial and commercial
water softener and demineralizer resins that were used to treat
either surface waters or well waters. Even relatively
clean-looking resin samples obtained from field samples show
varying amounts of bacteria. In addition, the desirability of
avoiding an excessive growth of bacteria is obvious if one
considers that fever-causing toxins, i.e., bacterial waste
products (pyrogens), can possibly be discharged from these units
into the treated water supply.
There are two types of contamination problems. The
first is surface fouling of the beads or particles wherein the
contaminant is absorbed on the surface of the ion exchange
material and continuous layering of contamination occurs. The
second is ionic particle fouling wherein contaminants diffuse
into the particles, and are bound to internal exchange site
within the resin. In view of the listed problems, it is
~ 218~Y~
desirable for the operator of ion exchange units to remove the
contaminants from the resin. An added incentive for doing so
is, of course, the added expense of operating contaminated ion
exchange units. For example, a unit that is down to 25% of
its original operating capacity requires four times as many
chemical regenerations, thereby increasing chemical and utility
costs. The total cost for extra manpower needs, regenerant
chemical costs, waste disposal costs, etc., can be extremely
high, depending on the extent of organic contamination.
If ion exchange units could be maintained in a clean
state to assure continuously optimum performance of the units,
a major advance in the art would have been achieved.
As further background reviewing pas-t attempts to
solve the problems outlined above, the following United States
patents are cited:
U.S. Patent No. 3,442,798, issued
May 6, 1969-~describes concentrating organic
combustibles in waste water on a carbonaceous surface
adsorbent such as lignin charcoal, bone charcoal,
powdered coke, powdered coal, activated charcoal,
activated carbon, and the like, and then oxidizing an
aqueous dispersion of the adsorbent containing the
adsorbed combustibles.
U.S. Patent No. 3,444,078, issued
May 13, 1969--described use of granular activated
carbon in a water-purification filter, a gravel bed
underdrain, and recovery of activated carbon from
water treated for human consumption.
~L2~'7~ j
U.S. Patent No. 3,373,085, issued
March 12, 1968--describes recovery of phenol from
coke-works waste water by adsorption on coking coal of
the phenol in the waste water.
U.S. Patent NOr 3,57~,589, issued
May 11, 1971--removal from cooling water systems of
accumulated deposits of scale, mud, silt, sludge, and
other foulants by incorporating into water flowing
through the cooling water systems of a non-ionic surface
active agent and an acrylic or methacrylic acid polymer
or water-soluble salt thereof.
U.S. Patent No. 3,748,285, Wiltsey, et al., issued
July 24, 1973--treated ion exchange resins with
sulfonated detergents to provide clean resin beads.
U.S. Patent No. 4,102,707, issued July 25, 1978,
and U.S. Patent No. 4,045,244, issued
August 30, 1977--detaching and dispersing
microbiological products on support materials in contact
with aqueous systems by adding to the aqueous phase a
chemical having hydrogen-bonding characteristics and
including water-soluble acrylamide polymers and epoxy
compounds.
U.S. Patent No. 3,996,131, issued
December 7, 1976--preventing fouling of reverse osmosis
and ultrafilter membranes by coatin~ the membranes with
an adsorbant, with or without active carbon.
U.S. Patent No. 4,260,504, issued
April 7, 1981--preventing formation of deposits on walls
of heat exchangers wherein ethylene glycol/water
circulates by mixing with the ethylene glycol/water
--6--
'12~347~
about 0.3-5~ w/w of a suractant which is the production
of addition of ethylene oxide and 1,2-propylene oxide or
a monohydric alcohol, water, a diol or a triol, 6~-90%
of the fixed oxides being oxyethylene groups.
THE INVENTION
The invention is a novel process for improving,
restoriny, and maintaining the performance of water-treatment
¦solids which are, or tend to become, fouled with organic
substances, micro-organisms, and waste products thereof. This
novel orocess comprises the cyclical treatment of these
water-treatment solids with an effective amount of a non-ionic
surfactant and a bio-dispersant.
The process of this invention can be improved by using a ¦
biocide in conjunction with the non-ionic surfactant and
bio-dispersant. The biocide to be used in conjunction with the
surfactant/bio-dispersant may be chosen from the group consisting ¦
of fatty quaternary ammonium salt biocides, bromonitrilo
substituted biocides, isothiazoline, and oxidative biocides. The
fatty quaternary ammonium salt biocides are best exemplified by
alkyl dimethyl benzyl ammonium chloride biocide compounds. The
bromonitrilo substituted biocides are best exemplified by dibromo ¦
nitrilo proprionamide. The isothiazoline biocides are commercial ¦
biocides manufactured by Rohm & Haas Co. and made available as
KATHON 886, described in the Rohm & Haas product bulletin,
DIC-76-3, May, 1377, which is incorporated by reference herein.
The oxidative biocides are best exemplified by such materials as
chlorine, bromine, hypochlorite salts or acids thereof, and
hypobromous salts or acids thereof. The use of these oxidative
biocides also has the potential advantage of using the oxidizin~
- * Trademar~
~ I
~ I
, I -7-
, l
1;~18~5
power of chemicals such as chlorine or sodium hypochlorite to
decreas~e through oxidative mechanisms the molecular weight of
hydrophobic compounds such as biological degradation products and~
biological waste products in such a way as to render these
products more hydrophilic or dispersible in water.
The process of this invention can be applied to such
water treatment solids as ion exchange resins, carbon adsorption
packing, gravel and sand bed filters, ion exchange membranes,
reverse osmosis membranes, and the like. Each of the above
classifications of water-treatment solids are subject to becoming
fouled with organic substances, soluble or insoluble iron,
micro-organisms and their waste products, and natural organic
substances derived from the waters used to feed the
water-treatment solids of this invention.
The preferred water-treatment solids which are most subject to
improvement, restoration, and maintainence of performance are ion
exchange resins which are used to remove ionic species from
contaminated feed waters prior to these waters being used in
steam generation and for other utility uses. These ion exchange
resins can be chosen from gel-type cation resins, gel-type anion
resins, macro-porous cation resins, and macro-porous anion
resinsO These processes may be used to improve, restore, and
maintain the performance of these ion exchange resins by either
of two processes or combination of these processes.
In addition, my invention provides an improved method o~
backwashing ion exchange resins which comprises conducting said l
backwash operations in the presence of a revitalizing agent which
is present in the backwash cycle for the first 50% of the
backwash operation. My invention includes backwashinq treatmentj
within the zone of resin operation, and, if desired, separately
-8-
lZ184~5
therefrom, that is, the backwash treatment may be completed
during normal resin operations or may be completed in separate
operations when the resin5 would not be immediately placed back
into an operative mode.
Process Parameters
The process which improves, restores, and maintains the
performance of ion exchange resins and other water-treatment
solids can initially be a process by which an effective amount o~
a combination of a non-ionic surfactant with a bio-dispersant is
added to the resin which has become fouled with organic
substances, micro-organisms and their waste productsl In a batch
clean-up type process. This batch process entails the addition
of from about 50 to about 2500 ppm (based on two bed volumes) of
the active formulation to this fouled resin bed, preferably at
elevated temperatures and for periods of time of at least 24
hours. These concentrations are based on a double volume of the
resin bed or the ion exchange resin bed being treated. A
preferred range is from 200 to about 1000 ppm of the active
ingredients andthe preferred treatment occurs at temperatures
between 100-180F for times of about 20-24 hours with
airlancing ~sparging) or rapid water circulation used for mixing
and contact purposes.
When this batch system is used to treat water-treatment
solids to remove fouling contaminants, it may be added along with
and simultaneously with a fatty quaternary amine biocide such as
an alkyl dimethyl benzyl ammonium salt. This quaternary amine
biocide is used along with the surfactant and dispersant and may
be present in an amount of from 1 to 50~ by weight of the
combined surfactant/dispersant formulation. The biocide is
1~1847~
preferably used from 10 to 30~ by weight based on the weight of
the tot~l mixture of the three biocide/surfactant/bio-dispersant
ingredients. The biocide, KATHON 886, described above, may also
be used as an effective biocide along with the
surfactant/dispersant formulation.
As was previously explained, the addition of an
oxidizing biocide to the treatment mixture often is helpful in
reducing the molecular weight of hydrophobic contaminants and
micro-organism waste products. The oxidizing action of these
biocides can tend to make hydrophobic contaminants hydrophilic
and assist in their dissolution or suspension. This action tends
to make these materials more readily removable during a wash and
rinse cycle.
Prior to the resins being placed back into service, the
resin bed is thoroughly washed with water to remove the last
vestiges of the revitalizing agent formed by the combination of
surfactant, bio-dispersant, and, optionally, biocide. This is
normally completed during the remainder of the backwash cycle and
during the regeneration sequences.
The second process, which is the preferred process, is a~
continuous cyclic treatment using the chemicals described above
and below in the following manner. Each ion exchange resin goes
through a typical cycle. Initially, the new, fresh resin is
charged to the resin bed, wetted, and regenerated with
regeneration chemicals. These chemicals are rinsed from the bed
with wash waters and the ion exchange bed is then placed in
operaton for the purpose of removing unwanted ionic species from
feed waters requiring treatment prior to the use of these treated
waters in steam generation or other utility applications. After
_.
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lZ1847~
a prescribed period of time, these ion exchange resins lose their
capacity to remove required quantities of contaminating ionic
speciesO At this point in time, the resins are backwashed by
upflowing waters through the resin bed to expand the bed volume
by about 50 volume percent for the purpose of discharging from
the bed any dispersed contaminating and insoluble species which
have a lighter density than the resin beads themselves. ~his
backwash cycle normally is obtained at dn upflow water flow rate
of approximately 1 to 5 gallons/minute per cubic foot of resin
contained in the resin bed.
Following this backwash cycle, the resin beds are
allowed to settle and regenerating chemicals are added, flushed
through the resin bed, and subsequently rinsed from the bed
before the bed is placed back into operation.
The preferred process of our invention is the addition
of the cleaning chemicals described above, and to be described
more completely below, to the backwash cycle prior to addition of
regeneration chemicals. The preferred process is the addition of
these treatment chemicals to at least the first 10%, but no more
than the first 50%/ of the volumes used to backwash the resins.We
have called this the preventive maintenance mode of this
process. Preferably, these treatment chemicals and cleaning
solutions are added during the first 25% to 40% of this backwash
rinse cycle. In practice, this means metering into the backwash
waters during the first 10 to 50% of the time allotted to
backwash the resin at a relatively constant backwash flow rate, a
relatively constant metered flow of the treatment chemicals using
the non-ionic surfactant and bio-dispersant, and optionally the
biocides. During the last 50% to 90% of the backwash, the
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1~184~5
chemical feed is no lon~er added and the remainder of the
backwash waters are used to flush the treatment chemicals and
contaminating residues from the system.
After the treatment chemicals are added and flushed from
t~e resin bed, the resins so treated are then subsequently
regenerated using standard regeneration chemicals and techniques~
When treating the resins in this preventive maintenance
mode, the use of chemicals may be decreased in regards to the
batch concentrations mentioned above. The combination products
including non-ionic surfactants and bio-dispersants, optionally
with or without addition of the biocides previously mentioned,
may be added to the backwash cycle at a concentration ranging
from about 10 ppm up to about 200 ppm of active ingredient based
on backwash water volume. If this concentration range is
maintained at each and every subsequent backwash cycle, the
benefits of this invention are obtained. The further addition of
from about 5 to about 200 ppm of the biocides mentioned above,
preferably from about 10 to about 100 ppm of one or more of these
biocide materials can improve the effectiveness of the
surfactant/bio-dispersant tre~tment agent in many instances.
~ ll
The Non-Ionic Surfactants
The non-ionic surfactants of this invention preferably
have an HLB between 6 and 14. HLB stands for the hydrophilic
lipophilic balance and is used as described in the publication by
McCutcheon's Publications on Detergents and Emulsifiers, North
American Edition and International Edition, 1974 Annuals,
published by McCutcheon's Division, Allured Publishing
Corporation, 45 N. Broad St., Ridgewood, New Jersey, USA. These
lZ~84'-~5
non-ionic surfactants are preferably cho5en from the group
consisting of the non-ionic ethylene oxide adducts of alkylated
phenols, the non-ionic ethylene oxide adducts of fatty alkyl
alcohols, the non-ionic sorbitan esters, and the non-ionic alkyl
aryl polyethylene glycol ethers. The preferred non-ionic
surfactant is ethylene oxide adducts of alkylated phenols which
have an HLB between 6 and 14. The most preferred non-ionic
surfactant is an ethoxylated nonyl phenol containing about 9
moles of ethylene oxide.
The Bio-Dispersants
The bio-dispersants of this invention are preferably
chosen from the group consisting of ethylene oxide condensates
with propylene oxide adducts on propylene glycol having an
HLBbetween 4 - 10 and a molecular weight between 1000 - 5000,
non~ionic polyethoxylated straight chain alcohols, tris
cyanoethylated cocodiamines, polyoxyethylene sorbitan
ester/acids, non-ionic N,N, dimethyl stearamides, non-ionic amine
polyglycol condensates, and non-ionic ethoxylated alcoholsO
Table r shows the types of chemicals which have been demonstrated;
to have bio-dispersant properties.
_. .
~LZ~ 7S
TABLE I
Evaluation of Compounds for Bio-Dispersancy
10 ppm with 1 hour contact
_ _
Data Collected with Biometer
Dis~ sant Chemical ~ype ~ Biomass Change
non-ionic (polyol) condensate of 66.4%
ethylene oxide with hydrophobic
bases (propylene oxide with
propylene glycol)
non-ionic polyethoxylated straight 58.5
chain alcohol
tris cyanoethyl cocodiamine 47.3%
polyoxyethylene sorbitan ester of 45.8%
fatty and resin acids and alkyl
aryl sulfonate blend (non-ionic)
cationic ethylene oxide condensation 35.8%
products of Duomeen T *
non-ionic N,N-dimethyl stearamide 34.7~
monoamine (cationic) (cocomononitrile) 31.3%
Low MW poly-acrylate (MW 1000-10,000) 31.1%
non-ionic - amine polyglycol 30.0
condensate
cationic - cocodiamine 25.6~
non-ionic ethoxylated alcohol 21.2%
Trade Mark; Duomeen T is an N-tallow-trimethylene
dlamine .
~2~847~
The % biomass change in Table I was measured by exposing
a slime mass previously grown and attached onto a surface to
clear recirculating water at about 100 F. The water contained
10 ppm of each of the indicated biod:ispersants and it was allowed
to recirculate at temperature for one hour. At the end of that
~time period, a biomass assay was made of water collected in a
¦common basin by using a duPont 760 Luminescense Biometer which is
¦described in the publication, duPont 760 Luminescence Biometer,
¦published in December, 1970, and described in U.S. 3,359,973.
I
This Table shows the percent of clumped biomass
dispersed by treatment with 10 ppm of the indicated dispersant.
Although other dispersants were tested which had lower than 20%
effectiveness, this data is not presented since any dispersant
¦having less than 20~ effectiveness in these tests would be found
¦not to function adequately in this invention.
Revitalizing Agent--Surfactant/Bio-Dispersant Formulations
l The weight of surfactant to dispersant in the treatment
¦mixture can vary from about 0.1:10 to about 10:1 and preferably
¦is from about 1:2 to 2:1. A 1:1 weight ratio has been found to
be particularly effective.
Where a quaternary amine biocide is used along with the
surfactant and dispersant, it can be present in an amount of from
1 to 50% by weight and preferably from 10 to 30~ by weight based
on the weight of the total mixture. These cationic biocides are
preferably not used when cleaning cationic exchange resins.
I 1,
~ 15-
~Z~a.L~5
The Biocides
The biocides of this invention are chosen from the group
of fatty alkyl quaternary salt b:iocides, non-ionic bromo, nitrilo
substituted proprionamides, the isothiazolines, and the oxidative
biocides. The fatty al~yl quaternary salt biocides are
exemplified by and are preferably an alkyl dimethyl benzyl
ammonium chloride quaternary ammonium salt biocide. The
non-ionic biocide may be preferably dibromo, nitrilo
proprionamide, although this material is not stable under basic
pH conditions, so its effective use is limited to neutral or
mildly acidic conditions. The isothiazolines are best described
as KATHON 886 and primarily manufactured by the Rohm & Haas Co.
These biocides are described in a previously referenced product
bulletin, made a part hereof.
The oxidative biocides are materials such as chlorine,
bromine, hypochlorous acid, hypobromous acid and alkali metal
salts of the hypochlorous and hypobromous acids. Herein, alkali
metal salts means those salts containing sodium, potassium,
ammonium, and rubidium cations.
Having described the batch process and the continuous
cyclic preventive maintenance process: and having described the
non-ionic surfactants and bio-dispersants of this invention; and
having described the preferred biocides which may be used in
combination with the non-ionic surfactants and bio-dispersants of
this invention; therefore, the application of these chemicals in
the processes for improving, restoring, and maintaining
performance of water-treatment solids which are fouled with
organic substances, micro-organisms, and waste products thereof,
can now be best described by example.
_ .
1~8~7 ~
EXPERIMENTAL STUDIES
1. Effe t of invention on the performance of
contamina-ted cation exchange resins.
The effect of the subject invention on the operating
capacities and leakages of cation exchange resins contamina-ted
with miscellaneous organic substances, bacteria, and bac-terial
waste products was observed in these tests. Two resins had
very large amounts of a sticky, gelatinous mass coa-ting the
particles and in the form of greenish-grey flocks, and one
resin contained a lesser amount of foulan-t. The first two
resins had a foul odor while the third had only a faint, bu-t
still objectionable, odor. The materials used for the cleaning
of these resins were a surfac-tant, namely, e-thoxylated nonyl
phenol (9 mol.) and a bio-dispersant, namely, polyoxypropylene
polyoxyethylene condensate (cloud point 32C.); and a quater-
nary amine, namely, alkyl dimethyl benzyl ammonium chloride.
In part, the quaternary amine may act as a surfactant
solubilizer.
In order to determine the effectiveness of removing
organics, bacteria, and bacterial waste products from resins
by the subject process, the quantities of chemicals and reaction
times selected were higher than actually needed.
In the following experimental data reference is
made to the attached figures in which:
Fig. 1 represents hardness leakage for the procedures
of Test 1.
Fig. 2 represents hardness leakage for the procedures
of Test 2.
Fig. 3 represents hardness leakage for the procedure
of Test 3.
~LZ~84~$
Fig. 4 represents the improvements ob-tained in a
commercial installation.
Figs. 5 through 12 represent results obtained from
monitoring a large commercial installation during a preventative
maintenance program.
Test No. 1, Strong Acid Cation Resin
This resin contained substantial amounts of large
and medium~sized greenish-grey flocks, and the beads were
fairly evenly coate~ with a gelatinous-type mass that felt
slimy to the touch.
Test Conditions
A 300 ml quantity of the resin was added slowly to a
one-inch Lucite tube, with a minimum of water between additions
of each sample portion. This assured that the slime-like flocks
* Trade Mark
-17a-
lZ~8475i
were evenly mixed throughout the resin column. The total bed
height was 22.5 inches. The resin was then allowed to stand
unattended for four days. After this time, the resin was lifted
by backwashing. A solid, cylindricaLly shaped mass moved upwards
like a piston, and only about 30-40~ of the total resin beads
separated from this solid mass. After 15 minutes, the attempt to
backwash the resin was discontinued. The water removed by
backwashing was 800 ml. This water showed a total bacterial
count of between 10 and 10 per ml, as determined with the
Orion Easicult Dip Sticks.
Test Water:
A 30 gpg (grains per gallon) total hardness test wate~
was prepared by adding 62.6 g CaC12, anhydrous,
70.2 g MgSO4~ 7H2O, and 28.35 g of NaHCO3 to 50 gallons of
D.I. water. The final water then contained 526 ppm of total
hardness, at a ratio of two~thirds calcium and one-third
magnesium, plus 150 ppm NaHCO3.
This test water was passed through the unit at a flow
rate of 80 ml per minute, or the equivalent of 2 gpm per cubic
foot of resin, until a hardness leakage of one grain per gallon
(gpg) was obtained.
Test l-A, Resin Backwashed Onl~:
The resin was then regenerated with the equivalent of
6 pounds of NaCl per cubic foot, or 270 ml of a 10% salt solution
per 300 ml of resin. The resin was then rinsed with one bed
volume of D.I. water at a flow rate equivalent to the regenerant
flow. ~t this point the hard water was passed through at 80 ml
per minute.
The hardness leakage and pressure drop data are shown in
Fig. 1. The average pressure drop through the resin unit was
4.5 PSI.
* Trade Mark
12~L8~Y5
Test l-B, Resin Airlanced and Backwashed:
The water above the resin used in Test l-A was drained
to bed level and airlanced for about three minutes with
compressed air at a flow rate that barely retained the 22.5
inches of resin within the 55-inch-long tube. The resin was then
backwashed with D.I. water at a flow rate to obtain a "normal"
expansion of the resin of 50 percent, until the effluents were
free of any debris. This required about 35 minutes of
backwashingO During this time, a considerable amount of a
fluffy, brown and green colored material was rinsed out. The
particles ranged from about .5 to 2 mm in size. The amount
backwashed was about 50 ml. The particles felt quite sticky. A
microscopic examination showed primarily translucent particles.
The test water was then passed through the unit as in
Test 1-A.
The results are shown in Fig. 1. The average pressure
drop across the unit was 1.5 PSI.
Test l-C, Resin Treated with a Surfactant, Bio-dispersant and
Biocide.
The resin used in Tests l-A and l-B was backwashed for
10 minutes, then one liter of a mixture of 1000 mg ethoxylated
nonyl phenol (9 mol.), 1000 mg polyoxypropylene polyoxyethylene
¦condensate (cloud point 32C), and 500 mg of alkyl dimethyl
¦benzyl ammonium chloride (as 50% solution of the quaternary
¦amine) was passed through the resin slowly at a temperature of
110-130F. for one hour. The solution was reheated and passed
through again for one hour. The last part of the solution was
left in the resin unit over a 48 hour period. Afterwards, the
resin was backwashed with D.I. water for 45 minutes, i.e., until
_ the backwash effluents were clear. The debris removed during
. I
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1 1;:184~5
this tlme was of a very small particle size, light enough to
require~ about two hours to settle in the collection vessel. A
microscopic examination of these particles, which were light tan
in color, showed translucent, gelatinous particles of various
shapes and thicknesses. The resin was then regenerated and
rinsed as described in Tests l-A and l-B. The capacity and
leakage properties of the treated resin were determined under
identical conditions used for the backwashed, or airlanced and
backwashed, experiment. A pressure drop could not be detected by
the pressure gauge used.
The results for leakages and capacity are shown in
Fig. 1.
As can be seen in the curves in Fig. 1, a significant
improvement in the capacity and the hardness leakage was obtained
through treatment with the surfactant, bio-dispersant and
biocide~ On backwashing the resin, it was found to be loose and
without any clumps. The beads separated nicely. The
backwash-effluents showed a moderate amount (about 3 ml) of
small, tan-colored flocks that come off very easily. Some flocks
( 1 ml) remained on top of the resin, along with some fiber that
came originally with this customer sample.
The supernatant of this sample showed zero bacteria when
tested with Orion Easicult Dip Sticks.
l l
¦ Test No. 2, Water Softener Resin
¦ This resin was contaminated with unusually large amounts
¦ of loose, large-sized flocks, and the resin beads were coated
¦ with a gelatinous-looking coating that felt slimy to the touch.
The coating was of a greenish-grey color.
_,
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lZ1847~;
Test Conditions:
~ A 300 ml quantity of this resin plus loose contaminants
were placed into a one-inch tube with a minimum of water between
addition of each resin portion. This assured that the slime-like
flocks were evenly mixed with the resin. The resin was left in
the unit for four days. After this time, an attempt was made to
backwash the resin. It moved upwardly in the tube in a single
piece and would not loosen by alternately turning the water flow
on and off.
Test 2-A, Airlanced and Backwashed:
_ _ .
The water was drained to bed level and the bed was
airlanced for about five minutes while the thin plastic tube used
to introduce the air was moved up and down repeatedly. The resin
was then backwashed for about 45 minutes until the effluents were
clear. The first 500 ml of backwash water showed a total
bacteria count of 107, as measured with an Orion Easicult Dip
Stick test method. The total amount of solids backwashed was
approximately 35 ml. This material settled to about 25 ml in two
weeks. The resin volume was reduced by about 5 ml, to 325 ml
total. A microscopic examination of the greenish-grey flocks
removed by backwashing showed translucent, gelatinous particles
¦ of uneven shapes and sizes. The resin was regenerated with 298
ml of 10% NaCl, or six pounds NaCl per cubic foot of resin. The
resin was then rinsed, and test water was passed through as
described in the experiment of Test 1.
The capacity and leakages are shown in Fig. 2.
The average pressure drop in the unit was 0.5 PSI.
Test 2-B, Resin Treated with a Surfactant, Bio-Dis ersant and
I _ P
_ ¦ Biocide
i The resin used in Test 2-A was treated with 500 ml of a
I solution containing 500 mg of ethoxylated nonyl phenol (9 mol. of~
~ ~L2~347S
EO), 500 mg of polyoxypropylene polyoxyethylene condensate (cloud
point 32 C.), and 250 mq alkyl dimethyl benzyl ammonium
chloridë (as 50~ solution of the quaternary amine), at
110-130F. for three hours by repeatedly reheating the solution
and passing it down flow through the resin. One bed volume of
this solution was left in the unit overnight. The resin was then~
backwashed to a 50% expansion for 45 minutes until the effluents
were clear. About 20 to 25 ml of a light brown substance in the
form of fine flocks were removed. The flocks were smaller than 1
mm diameter in size.
The supernatant of the resin showed zero bacteria when
tested with the Orion Easicult Dip Stick.
The resin was then regenerated as in Test 2-A. The used
regenerant was collected and showed a light yellow to tan color.
Foaming of the regenerant effluents was also noted. The resin
was then rinsed with 330 ml of D.I. water at the regenerant flow
rate, then fast-rinsed with test water. The test water was then
passed through the resin under identical conditions as used in
Test 2-A (at 2 gpm/ft3).
The capacity and leakage data are shown in Fig. 2.
A pressure drop could not be measured with the pressure
gauge used.
Foaming of the effluents was noted until 10-1/2 bed
volumes, i.e., 3.5 liters of test water, were passed through the
resin. At this point, also, no odor of any kind was noted. At
the end of the tests, the resin was backwashed by alternately
lifting and settling the resin. The resin still showed some
clumping, although much less than originally. But this test
indicated that, while a significant cleaning was achieved, not
all of the contaminants were removed. This resin was obviously
3L~84~7~i
so severely contaminated that a more drastic cleaning or repeated
cleaning is necessary. A microscopic examination showed dramatic
differences in the appearance of the resin, i.e., the cleaning
had removed a large portion of the original contaminants. This
¦ is also indicated by the improvement in the capacity and hardness
¦ leakage of the resin, as shown in Fig. 2.
¦ Test ~o. 3, ~ater Softener Resin
I _ _
This resin was only lightly contaminated with loose,
light brown flocks and some coating of the beads.
Test Conditions:
250 ml of resin plus the small amounts of flocculant
contaminant were placed into a one-inch tube, resulting in 20.5
inches bed height~ This resin was left in the unit for four
days. The resin was then lifted by a brief backwash. Several
small clumps were observed that did not break up as the resin
slowly sank through the water to the bottom of the tube.
Test No. 3-A, Airlanced and Backwashed:
The water was drained to bed level and the resin was
airlanced for five minutes by simultaneously moving the thin air
tube up and down in the resin bed. The resin was then backwashed~
for 35 minutes, i.e., until the effluents were clear. The amount~
of a fluffy, very small-sized material was about 7 ml when
freshly collected. This amount settled to 4-5 ml after a week.
The first 500 ml of backwash water showed a total bacteria count
of 105 to 106, as measured by the Orion Easicult Dip Stick
test.
The resin was regenerated with 225 ml of a 10% NaCl
_ _ solution, or six pounds NaCl per cubic foot of resin. The resin
. I
l ll
-23-
~.Z~8~L7~
was then rinsed and exhausted with test water under identical
conditions as used in all previous experiments.
The capacity and leakages obtained are shown in Fig. 3.
There was not enough pressure drop to measure it with
pressure gauge used.
Test 3-B, Resins Treated with a Surfactant, Bio-Dispersant, and
Quaternary Amine:
The resin that had been used in Test 3-A was treated
with 500 ml of a solution containing 500 mg ethoxylated nonyl
phenol (9 mol.), 500 mg polyoxypropylene polyoxyethylene
condensate (cloud point 32C.), and 250 mg of alkyl dimethyl
benzyl ammonium chloride (as 50% solution of the quaternary
amine), at 110-130F. for three hours by repeatedly reheating
the solution and passing it down flow through the resin. As in
Test 2-C, one bed volume of the solution was left in the unit
overnight. The resin was then backwashed until the backwash
water was clear, which required about 45 minutes. The total
amount of a tan-colored, flocky, fluffy material removed was
about 3 ml. A microscopic examination showed translucent,
gelatinous particles of a small particle size and of various
shapes and thicknesses. The supernatent of the resin was free of
bacteria, as measured by the Orion Easicult Dip Stick test. The
resin was then regenerated, rinsed, and exhausted with test water
under conditons identical to all previous tests. The spent
regenerant showed a light yellow color.
The capacity and leakage obtained are shown in Fig. 3.
E'oaming of the effluents stopped at about 2.5 liters of
test water passed through, or the equivalent of 11 bed volumes.
~Z~84'7~:;
The capacity of the resin that was airlanced and
backwashed only was close to the available capacity of this
particu~ar resin sample, i.e., about 23.0 liters of the test
water was softened by the 225 ml of resin. The chemical
treatment with the surfactant, bio-dispersant and quaternary
amine, therefore, had little to improve in terms of capa_ity (~ 1
liter test water was treated additionally). The improvement in
water quality, however, was significant. On the average, a
reduction from 6 ppm total hardness leakage obtained with the
resin as received, to 4 ppm with the chemically treated resin, as
can be seen in Fig. 3. The results obtained with this resin are
particularly interesting when one considers that this resin was
fairly new (10 months old) and had only a relatively small amount
of bacteria and miscellaneous organic debris coating the resin
and in the form of ]oose substances in the supernatant.
Test No. 4
In this test a commercial demineralizer system having a
history of rapid losses in operating capacity was treated in
accordance with the subject invention. The decrease in capacity
had required frequent resin replacement which represented a major
operating cost. The cation resin had to be replaced every three
years; the weak resin, every eleven months; and the strong base
resin, every eighteen months. The diminished resin life was due
to rapid fouling with natural organics, bacteria, algae, and
synthetic polymers. The adverse effect of the surface foulants
on the cation and weak base resin units was particularly evident.¦
The purpose of the test was to determine whether a
combination of a bio-dispersant and a non-ionic surfactant could j
remove sufficient foulants to restore the system to a useful
_, _ ~
-25-
~Z~847S 1l
capacity. In this test, NaOCl was added as an oxidizing agent, a
solubilizer, and an inorganic oxidative biocide.
~ In the test, water from a lagoon that collects natural
surface run-off water was pumped to a water treatment plant where
from 1 to 5 ppm of a synthetic polymeric coagulant was added.
The water was passed to a filtration unit to remove particulate
material and was then passed through the demineralizer system
consisting of four demineralizer trains, each tIain containing
400 cubic feet of cation resin, 225 cubic feet of weak base
resin, and 150 cubic feet of strong base resin. Resin
replacement of two of the four trains had been scheduled due to
lowered capacities. These two trains were treated in accordance
with the subject invention in the following manner:
Cleanin of Demineralizer Trains 1 and 2
g
Each unit of the two demineralizer trains was cleaned
separately.
1. Cation Unit of Train No. 1: (400 cubic feet)
Dosage: 1) 2500 ppm of a mixture of a surfactant and a
bio-dispersant. The surfactant was a non-ionic
liquid nonylphenoxy polyethoxy ethanol having an
HLB of 13.3. The bio-dispersant was a liquid
non-ionic block copolymer of propylene oxide and
ethylene oxide having an HLB of 7Ø
2) 250 ppm C12 added as bleach, or 2.5 gallons of
18% NaOCl per unit.
The unit was air rumbled through the backwash line every
hour for four hours, then left standing overnight. Foaming did
not occur, possibly due to the unusually large amount of
particulate matter loosened up during the cleaning. The next
morning the unit was backwashed at 300 gallons per minute for two
~ ~ lZl84~ ~
hours. At this point, the discharge water was clear. Foaming
was no longer observed after 30 minutes. Small particulate
matter still came off in large quantities. The surface coating
of the resin particles accepted Alcian Blue dye to an extent that
about 1/4 of most particles were coated with dyed substances.
This indicated the presence of polysaccharides, i.e. biological
waste products.
2. Weak Base Unit of Train No. 1: (225 cubic feet)
Dosage: 1) 2500 ppm of the mixture described above, 2 bed
volumes, or 4 gallons per unit.
2) 250 ppm C12 added as bleach, or 1.4 gallons of
18% NaOCl per unit.
Once again, the unit was air rumbled every hour for four
hours. Moderate foaming occurred, and air rumbling was stopped
when the foam reached the top of the unit. The unit was left
standing overnight, then backwashed for 1-3/4 hours until no more
particles or foaming was noticed in the effluent. The backwash
water cleared up much faster than the cation unit, i.e. less
particles were removed.
3. Strong Base Unit of Train No. 1: (150 cubic feet)
Dosage: Same solution strength. Total amount added was
2.5 gallons of the mixture described above and
0.95 gallons of 18~ NaOCl.
¦ This unit contained almost no loosened particles and
foamed during air rumbling and during backwashing. The addition ¦
of a chemical defoamer to the waste water was very effective in
¦ preventing foaming in the sewer lines.
¦ 4. All Resin Units of Train No. 2:
~ The conditions described for Train No. 1 were employed
_ _ ~ in treating Train No. 2 and the same amoun~ of chemicals were
used.
-~7-
~Z184~S
¦ The reaction time for the cleaner, however, was
maintai~ed at four hours. The cation unit was more severely
fouled than that of Train No. 1. Thus, a backwashing rinse of
2-1/2 hours was required versus 2 hours for the cation unit in
Train No. 1.
EXAMPLE 1
Preventive Maintenance Treatment of
Demineralizer Train No. 1
A preventive maintenance dosage of ~0 ppm of the mixture~
of surfactant and dispersant used in the above tests was fed into
the backwash water during approximately the first 10 minutes of
each backwashing of the cation, weak base and strong base units.
The product appears to be rinsed from the units during the
remaining backwash, i.e., 20 minutes additional, plus the normal
regeneration and regenerant rinse. The "final" rinse water taken
during the last two minutes of rinse showed a s~rface tension
equal to the raw water influent.
After several backwash cycles using this preventative
maintenance program, the defouling treatment restored the trains
to their maximum available operating condition. The length of
the run of Train No. 1 was increased from 485,000 gallons to
1,070,000 gallons, and an increase from 870,000 to
1,050,000 gallons for Train No. 2 was achieved. A resin analysis
showed only 81% of the original capacity remaining, i.e., all of
the available capacity of this used resin was restored.
Collected data after five months of operation
established that the preventive maintenance treatment of Train
No. 1 reduced the decrease in the lengths of the runs to about
only 12 to 15%, while Train No. 2 showed a rapid decrease of 45
in the lengths of the runs, i.e., the relative amounts of water
treated.
-28-
~ ~.Z184~
This trial illustrates that the preventive maintenance
program is most effective. The demineralizer Train No. 1 was
initially cleaned and treated with a 1:1 weight ratio mixture of
surfactant and bio-dispersant plus chlorine. It was then
continuously and cyclically treated with the same mixture of
non-ionic surfactant and bio-dispersant to provide optimum
operating capacities and excellent low leakage characteristics,
typical of clean demineralizer resins. In contrast, the
demineralizer Train No. 2 that was effectively batch cleaned but
not further treated with a cyclical prevention and maintenance
program showed a decrease in its operating characteristics.
The success of removing the surface contaminants was
probably due in part to the combination of surfactant,
dispersant, and chlorine as an oxidative biocide. It is also
believed that chlorine can interact with any contaminant polymer
chain at branch sites causing breakage of the chain, resulting in
a lower molecular weight and the formation of a more water
soluble polymer residue. The alkalinity provided by the use of
the bleach may also be beneficial in converting the polymer to
its more water soluble sodium salt form.
EXAMPLE 2
2. Improving the performance of a Contaminated Strong
Base Anion Exchange Resin
The following tests were made to study whether it is
feasible to improve the performance characteristics of fouled
anion resins through the use of a surfactant and bio-dispersant
as an additive to the currently used cleaning solution, i.e., a
mixture of salt and caustic. Ultimately, it is hoped to provide
sufficient evidence for the usefulness of such components to help
maintain anion resins in peak operating condition, i.e., to
prevent the accumulation of organics instead of allowing the
-29-
~ ~Z~147~ 1
resin to become fouled and waiti~ until the cost of operating a
unit is so high and the water quality produced is so poor that
the plant manager faces a serious operational problem.
The resin selected was a customer sample that had been
received recently. The customer had experienced both poor water
quality and high pH with this resin. This sample contained a
moderate amount of tan-colored, flocky particles of varying
shapes and sizes, and the resin itself was coated with moderate
amounts of a slimy substance. The sample had a foul odor that is
not characteristic of new anion exchange resins. The water
surrounding the resin particles had a total bacteria count of
about 107, as measured by the Orion Easicult test, indicating
the resin environment was microbiologically fouled and
comtaminated.
The sample showed only 79% of its original total
capacity and 67% of its original salt splitting capacity. It
contained 10~ broken beads, was contaminated with 12 g Fe and
26 g Si per cubic foot of resin, and was also fouled with large
amounts of deeply colored organic substances.
A. Capacity and Leakage Tests Before
Chemical Treatment
Two 40 ml samples of this resin were placed into a 50 ml
burette, exhausted with water containing 585 ppm hydrochloric
acid calculated as CaCO3, to a 50 mmhos (micromhos) leakage.
The resin was then regenerated with five pounds NaOH per cubic
foot of resin, rinsed and exhausted with the test water of 585
ppm total hydrochloric acid as CaCO3.
One sample (column A) showed an effluent having a
conductivity of 10 to 21 micromhos. The other sample (column B)
resulted in water having a conductivity of about 25-30 mmhos but,
., ~
-30-
l ~ lZ18475
at the end of the cycle, it was noted that this sample contained
slightly more debris than the first sample.
- B. Capacity and Leakage Tests After Chemical Treatment
Column A was treated with the normally recommended
treatment of 10 pounds NaCl and 1 pound NaOH per cubic foot of
resin, applied as a 10~ solution at 140 F. for three hours.
The actual amount used was 60 ml of soluti~n per 40 ml of resin.
Column B was treated with a mixture of 60 ml of the
above solution, diluted to 1;0 ml total with an aqueous solution
of 50 mg ethoxylated nonyl phenol (9 mol.), 50 mg of
polyoxypropylene polyoxyethylene condensate cloud point 32C.
and 25 mg of alkyl dimethyl benzyl ammonium chloride, a
quaternary amine biocide. Treatment time was three hours, at
140F.
Both columns were left without heat overnight with
enough of each treatment solution surrounding the resin beads.
The resin samples were then rinsed with 0.2 N HCl followed by
water, regenerated, rinsed, and exhausted, as under A. The
accumulated treatment effluents were both very deep red-brown in
color. The water quality obtained, however, was quite
different. The resin treated with the surfactant,
bio-dispersant, and biocide mixed with salt and caustic produced
a water with a conductance of about 5 to 10 mmhos less than the
column treated with the surfactant, etc., and provided a water
quality of about 6 mmhos for about two-thirds of the test, while
the resin treated without these additives resulted in a water
quality of about 15 to 20 mmhos throughout most of the test, with¦
about 5% of the run giving the water quality of 8 mmhos.
The initial one-third of the water treated with both
res s showed a light tan color, more color was noted with ~le
-31-
~X~8~si
resin treated with surfactants, etc. This seems to substantiate
the appraisal that a strong base resin that has been allowed to
accumulate organics may very likely never be completely
cleaned, due to the low mobility of large molecular weight
organics. In other words, a resin that has accumulated these
substances over a long time period cannot be expected to be
completely cleaned in the relatively short time period set
aside for cleaning. The positive improvement noted here,
however, provides proof of the validity of the concept of
using surfactants and bio-dispersants to help remove organics
from anion resins that are otherwise difficult to displace
from the resins. In addition, these results indicate further
that the components used are excellent candidates for preventing
the accumulation of organics on anion exchange resins.
EXAMPLE 3
3. Product Preparation
A total of four products were prepared. The products
included a biodispersant (polyoxypropylene-polyoxyethylene
condensate prepared as described in United States Patent
2,674,619) and a surfactant (ethoxylated nonyl phenol [9 mol.
of EO]), with or without a quaternary amine (alkyl dimethyl
benzyl ammonium chloride) biocide.
All products were formulated at 50~ solutions in
water. The individual components were mixed at 60-65C.
(140-150F.) without any difficulty. At lower temperatures,
the mixing is somewhat more difficult; the viscosities of the
solutions during mixing being such that considerable time was
needed to attain a uniformly mixed solution. The preferred
mixing order was: water, surfactant followed by the dispersant,
and finally the quaternary amine biocide.
-32-
~2~347~
_roduct Components and Mix Order
Product Water Surfactant Dispersant Dispersant Quaternary
No. _ B* Amine
CX-29 50% 20% 20% --- 10%
CX-30 50% 25~ 25% --- ~~~
CX-31 50% 18.2~ --- 18.2% 13.6%
CX-32 50% 25% --- 25% ---
*Dispersant B is of the same type as Dispersant A except that it
has a cloud point (32C.) which is 8 higher than that of
Dispersant A.
All of the products prepared are colorless, clear, and
somewhat viscous solutions. They solubilize readily in water at
any concentration and at any temperature.
These CX-number products were subjected to stability
tests at 120 F., 75 F., 32F. and 0F. After two weeks,
no change was observed except that the products froze at 0F.
Upon thawing, a complete freeze-thaw recovery was observed.
The following surfactants have been used with success in
the process:
Makon 10 -- a non-ionic, liquid alkylphenoxy
polyoxyethylene ethanol.
Surfonic N-85 -- a non-ionic, liquid nonylphenoxy
polyethoxy ethanol.
Example 4
The effectiveness of our combined non-ionic surfactant
and bio-dispersant program for maintaining the capacities of ion ¦
exchange resins was tested at a plant in southern United States.
One cation and two anion demineralizer units were fouled by water
containing organic substances from natural sources and also
possibly from a sewage treatment plant upstream. The cationic
* Trade Mark
I 1,
I
-33-
; ~z~L847'~
exchange resins showed a surface coating with undefined organics,
bacterial slimes, and with detection of micro-organisms. The
anionic exchange resins were severely fouled with dark brown
substances thought to be lignins and tanins. Also, substances of
an oily or greasy nature were detected on the anionic exchange
resins causing clumping of the resin particles. All three units
were treated with a ccmbination of my preferred non-ionic
surfactant and bio-dispersant in combination with sodium
hypochloride used both as an oxidizing agent as well as a biocide.
Water passing through the demineralizer units ranged in
temperature from 85 F. to about 95F. during the test. The
water contained substantial amounts of natural organics plus the
discharge from a sewage treatment plant upstream. Although no
massive analytical attempt was made to identify each of the
organic contaminants, a reasonable estimate of these contaminants~
could include the presence of tannins, lignins, fatty acids,
micro~biological organisms, and the waste products thereof.
The cation exchange unit had been charged with
Permutit QB and was tested as having a total exchange capacity
equal to 1.55 milliequivalents per milliliter whlch was about 77%
of the original ion exchange resin capacity. The anion exchange
unit #l was charged with Dowex 11 which had a salt-splitting
capacity equal to 0.44 milliequivalents per milliliter or about
34% of the original capacity, was tested as having 0.45
milliequivalents per milliliter of weak base groups compared to
no weak base groups detectable on new, fresh resin, and had a
total exchange capacity of 0.89 milliequivalents per milliliter
which corresponded to about 68% of the original capacity.
The anionic exchange resin unit #2 was charged with
IRA-402 from Rohm ~ Haas which tested as having 0.38
* Trade Mark
-34-
~ ~7~18~7S
milliequivalents per milliliter salt-splitting capacity, equal to
about 29~ of the original capacity. The weak base capacity of
this resin was tested as having 0.71 milliequivalents per
milliliter although no weak base capacity is detectable on fresh
new resin. The total exchange capacity of this anion unit resin
was 1.09 milliequivalents per milliliter which tested out as 84%
of the original fresh new resin capacity.
Treatment of the cationic exchange resins with Alcian
Blue Dye indicated the presence of polysaccharides such as
bacterial slimes, wood sugars, and slime-forming bacteria.
As stated above, the anionic resins were dark in color,
formed small clumps, and had white coating which dissolved only
with prolonged contact with hot caustic. Again, although no
analyses were run, this hot caustic dissolution would be typical
of silicate deposits which would tend to form when soluble
silicates are passed over an acidic resin, for example, a resin
with high percentages of weak base groups.
Each of the three units were treated initially with a
batch treatment containing 2500 ppm of a combination product
which, in turn, contained the preferred non-ionic surfactant and
bio-dispersant of this invention. In addition, 250 ppm of
chlorine was added (as sodium hypochloride) based upon 2 bed
volumes of water. The treatment of the anion resin units also
included the addition of 100 ppm of a quaternary amine biocide.
The units were opened, the water drained to about 6"
above the resin, and the chemicals listed above were added.
Water temperatures were between about 85F. to 90F. during
the addition of these chemicals. The units were airlanced
immediately and then every hour for four hours. Foaming inside
the units was excessive and airlancing was stopped when foam
appeared at the top of each of the resin bed units.
~ Trade Mark
~2~8~7S
Each of the units were then backwashed to overflow until
the effluents were free of particulate matter and little or no
foaming was observed. This required about 45 minutes for the
cation resin bed units and about 75 minutes for each of the anion
units. All three units were then each regenerated in their
normal manners.
The preventive maintenance treatment was started
immediately following the batch cleaning of cation unit #l and
also of anion unit #1. The anion unit #2 was left without any
further treatment for the benefit of being able to compare the
performance o~ this unit with the anion unit #1, thereby
comparing two identical units with the ability to observe the
effect of periodic maintenance treatment vsO the performance of
the unit only being exposed to a batch cleaning treatment.
The preventive maintenance program consisted of feeding
80 ppm of a 25% aqueous solution of the combined product of a
non-ionic surfactant with a bio-dispersant for the first 10
minutes of each backwash followed by a 20 minute continuation of
backwashing with standard clean waters and followed subsequently
by normal regeneration. Table II presents data which compares
the results obtained with these online field tests.
-36-
;,
~2~ 75
- TABLE II
OPERATI~G CAPACITIES BEFORE AND AFTER TREATr~E~T
Cation Unit ~o. 1 Anion Unit ~o. 3
Cleaned, plus Anion Unit No. 2 Cleaned, plus
~y~ Preventive Maintenance Cleaned Onlv Preventive ~aintenance
Day 1 Cleaned unit plus pre- Cleaned Unit ---
ventive maintenance ~o ~urther treat-
started ment
Day 2 56,000 gallons over 37,000 gallons 18,aoo gallons less
meter setting less than meter than meter setting
setting (silica ~silica leakage)
leakage)
~ay 3 ___ ___ ___
4 --- 42,000 gallon Cleaning ~lus pre-
Day less than meter ventive maintenance
setting started
Day 5 30,000 gallons over --- ---
me~er setting
Day 6 --- Regeneration be- 20,000 gallons left
fore leakage on meter (sillca
-30,000 gallons le~kage)
less than meter
setting
Day 7 24,000 gallons over --- 18,000 gallons le~t
meter setting on meter (sillca
leakage)
--- 37-
Careful observation of the tabular data indicates the
effects of cleaning and the effects of t preventive maintenance
programO' Plant operating personnel were requested to monitor
these units to their true end-point, that is, silica leakages for
anion units and a decrease in the free mineral acidity for the
cation unit. Normally, this plant operated its demineralizer
units by automatic water meter shut-off devices. When a
predetermined number of gallons of water had passed tilrough the
units, the units were automatically backwashed, regenerated, and
rinsed prior to exposure of water requiring this treatment. In
the case of the anion units, normal runs went well beyond the
leakage of silica. Our tests indicated that the anion units lost
no more capacity, but cleaning in the manner of our batch system
did not increase the operating capacity. This is not too
surprising since the data on the original resins indicated that
these resins had deteriorated dramatically to such an extreme
that a continuation of this trial was questionable.
However, the preventive maintenance program did indicate
that the extent of fouling was reduced beyond the reductions
achieved using the batch cleaning process.
The results of this evaluation also indicated that the
surface coating fouling the cation resin was removed and that the
throughput for this resin was increased from 240,300 gallons per
run to 270,000 gallons per run. A subsequent application of the
preventive maintenance dosage of our invention assisted in
maintaining this extended throughput increase.
The ionically fouled anion resins showed no change in
throughput initially. However, even with these relatively
short-term tests, these ionically fouled anion resins did show no
furt r decrease in operating capacities and characteristics.
-38-
~21~,~7~i
The preventive maintenance program continued over a time
period of about 14 months. Over this period of time, the run
lengths-on the severely fouled strong base anion resins
dramatically improved from approximately 170,000 to 227,000
gallons and have been maintained at this level for the last 4 of
that 14 month period. The water quality of the total
demineralizer train was dramatically improved as well.
~ lso noteworthy is the observation that the chemical
capacity, that is, the salt-splitting capacity, did not decrease
any further but, rather, increased to a slight degree. In
essence, the tests shown in Fiy. 4 indicated that the application
of the preventive maintenance program increased the resin life by
at least 19 months and has successfully defouled what was
allegedly an irreversibly fouled anion resin beds.
Interestingly, the total exchange capacities of the resins
treated with the invention on a preventive maintenance program
remained unchanged for the entire length of this trial. This
indicates that the invention totall`y inhibits and prevents
further degradation of the resins and inhibits and prevents
additional losses of exchange capacities for these type resins.
In summary, this field trial comparison, particularly of~
the two anion unit trains, indicated that the demineralizer
trains had been gradually decreasing in capacity over a period of
about 2 or 3 years. This gradual decrease in efficiency was
attributed to resin degradation plus excessive buildup of natural~
organic foulants and micro-organisms and their waste products
that originated from natural waters as well as a sewage treatment
plant discharging upstream into the waters fed to these
demineralizer trains. This field trial compared both a batch
scouring, using the chemicals of this invention as well as the
_. _
1,
-39-
~Z18~S
preventive maintenance program using these same chemicals when
applied to the anionic and cationic units making up the
demineralizer trains at this manufacturing facility. The batch
scouring or cleaning procedure showed essentially no measurable
effect although the total run lengths did show a gradual increase~
After batch treatment, a feed pump was connected to the
backwash water line of the anionic unit and the chemicals of this,
invention were fed to the backwash waters during the ~irst
one-third of the total 30 minute backwashing cycle which occurs
prior to each regeneration. Chemical feed was at an 80 ppm based
on total volume of treated backwash waters. No other chemical
treatment or service to these units was provided.
At the time that the preventive maintenance program was
initiated, the total capacity of the unit on which this backwash
system was connected was 150,000 gallons. This run length
improved slowly and gradually over the next 14 months to a total
run length of 227,000 gallons.
Also extremely noteworthy is that the resin in this
anionic train had only 29% of its original salt-splitting
capacity and 8~% of its original total capacity when this trial
was initiated. A recheck of the capacities of this resin about
13 months later indicated that the resin had 32% of the original
salt-splitting capacity, indicating a gain of about 10% in the
chemically-available total exchange capacity. This indicates
that the continued preventive maintenance use of the chemicals of
this invention reduce further chemical degradation of these
anionic resins. The chemicals used throughout this test were a
l:l blend of an ethoxylated nonyl phenol containing 9 moles of
ethylene oxide and a bio-dispersant having been synthesized by
_40_
` ~LZ~ 7~;
conder.sing ethylene oxide with a propylene oxide adduct on
propylene glycol, giving a product having a molecular weight of
about 1500 - 5000 and an HLB between 4 - 10.
Example 5
An oil refinery on the Gulf Coast has 7 demineralizer
trains with a history of losing ion exchange capacity and
requiring long water rinses and regenerations. Resin fouling due
to various types of natural and synthetic organic materials as
well as micro-organism and micro-organism waste product
accumulation was suspected as major causes for this poor
operating history. The cationic and weak base anionic resins of
two trains within this demineralizer system were batch-cleaned
with the chemicals of this invention followed by a preventive
maintenance treatment on one train only. The batch cleaning
treatment improved the performance of these trains to a slight
extent. The demineralizer train receiving no further preventive
maintenance treatment remained at poor performance level. The
demineralizer train which did receive the preventive maintenance
treatment using the chemicals of this invention has shown an
appreciable and steady improvement.
The field trials at this Gulf Coast refinery were set up !
to compare results obtained on a demineralizer train #l vs.
demineralizer train #2. The train #l was maintained under the
standard practices of this refinery during the extended time
periods of this test.
The demineralizer train #2 was placed on the preventive
maintenance program requiring the addition of the chemicals of
this invention to the first 10%, but not more than the first 50%,¦
of the backwash cycle followed by standard regeneration and rinsel
~,= .
I I
-41-
~Z~8~$
techniques. The chemicals were added at each backwash over a
period of approximately 9 months. Both demineralizer trains were
initial~y backwashed and cleaned using the batch treatments
described above and using the chemicals of this invention. Prior
to th-s cleanup, the plant personnel had previously cleaned the
resins in the entire demineralizer system with caustic and
regenerative chemicals approximately two to three months prior to
this field test being initiated.
The results of the batch cleaning which followed closely
the total cleaning of the resins in place by plant personnel, the
results indicated that only slight improvements in resin capacity
regeneration chemical use and water use, in addition to water
quality, was observed. The slight improvement was observed,
however, in the train which received the treatment of this
invention.
However, the train which was receiving the preventive
maintenance, recovery, and restoration treatment of this
invention slowly and consistently improved the performance of the
resin, both the cation resin and the anion resin, in this
demineralizer train until the resin had recovered nearly all of
its initial capacity to treat waters containing anionic species.
This plant has remained on the preventive maintenance
restoration program until the present date. The results
continued to indicate that the resins, both cation and anion,
contained in this demineralizing train have maintained the
maximum resin capacity, salt splitting capacity, and also reveals
that no further resin degradation has occurred during the last 7
months of this particular field trial. A continuous improvement
in the run length of this demineralizing train has been recorded
by the personnel at this Gulf Coast refinery. Tables III, IV, V,
_
~8~L7~
,/ VI, and Figs. 5, 6, ~, 8, 9, 10, 11, and 12 indicate the results
obtained from monitoring the resin system during the preventive
malntenance program used to recover, improve, and maintain the
performa ce of these tater-treatment exchange resins.
-43-
~2~8~7~
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TABLE IV
PEREO~ANCE
DEMINERALIZER TRAIN NO. 2 OPERATING DATA
END E~D Ur8. T0TA~
DAY ~ COND~ CO~D. REGE~.TCTAL RU~
1.011 PP~ 6 MM00 15 ~.~e0..221,900 Ga1. 966,900 ~a1.
2.014 " 3 " 30 " 237,5Q~ "1,2S7,600 ~
3.~14 " 6 " 4; " 233,300 "1,125,910 "
4.011 " 4 " 40 " 227,700 "1,073,400 "
S.011 " 4 " 2~ " 235,500 ~'1,009,400 "
6.011 " 4 " 1S " 245,~00 "900,600 "
7 ..011 " 4 " 10 " 241,900 I~863,000 I~
8.017 " 7 " 120 " - 1,266,100 "
~.014 " - 30 " 216,500 "1,070,000 ~
1Q.014 " 5 " 16 " 320,000 "1C133,500 I~ .
4 " 5 " 17 " 2~0,000 "933,500 "
12.014 " 7 " 60 " 233,500 ~'1,140,000
13.Q14 " 6 " ~ 45 ~ 202,700 l~1,112,200 I~
14.017 " 3 " 28 " 259,300 ~945,200
15-.014 ~ 4 ~ 19 " 214,900 "936,600 I~
1~-.011 " ~ " 2~ " 214,j~0 "931,4~0 ~
17.014 " ~~ " 30 " 213,0~0 "95~,100 ~'
1~.017 " 6 " 70 " 21O~OJO "1,089,SOO "
19.014 " 5 " 3~ " 20a,0~q "1,027,~00
20.028 " 7 " 33 " 2~5,'~0 "1,213,000 ll
21.014 " 5 " 34 I~ 220 " ~0 "1,200,100 "
22.~14 " 9 " 1? " ~53,000 "1,05O,8CO 1'
23.020 " 1 " 41 " 25~,7~0 "1,251,500"
_
8~7S
TABLE V
PERFOR~L~NCE
DEMINERALIZER TRAIN NO. 2 OPERATING DATA
~D END W.B. TO~AL
D SiO~ COND. COND. REGEN.TOTAL RUN
24 .001 pp~ 3 ~o 36 ~0220,000 Gal. 1,245,800 Gal
.01~ " 3 " 25 " 223,700 "1,328,400 "
26 .014 " 4 " 19 " 253,300 "1,240,300 "
27 .014 " 9 " 90 " 211,800 "`1,250,000 "
28 .016 " 6 " 6 " 233,900 "1, 280,400 "
29 .014 " 6 " . 12 " 218,200 "1,052,200 "
.01~ " 4 " 28 " 226,000 "
31 .014 " 6 " 70 " 241,000 "1,291,300 "
32 .014 " 5 " 80 " 243,40~ "1,S77,100 "
33 . .017 " 4 lOO " 261,000 "1,500,000 "
34 _ - - 258,~00 "1,332 9 500 "
.014 " 6 " 52 " 237,000 "1,155,200 "
36 .014 " S " 70 " 256,100 "1,414,~00 "
37 _ - - 235,00~ -
38 .014 " 5 " 22 " 267,900 "1,151,300 "
39 .011" ~ " 20 " 300,000 "1,050,500 "
4a .017" 4 " ~2 " 249,500 "1,183,200 "
41 .017 " 4 " 18 " 243,700 "1,097,300 "
4 2 .014 " - ~ " 20 " 254,800 " I, 003,900 "
43 .014 " 8 " 75 " 300,000 "1,383,600 "
44 .017 " 2 " 1~ " 290,QOO "1,113,800 "
_ 45 .019 " 10 " 22 " 264,000857,400 "
46 .011" :~" 20 " 26~,000 " 1,364,900 "
--46 --
~X~8~715
TABLE VI
PERFORMANCE
DEMINERALIZER TRAIN NO. 2 OPERATING DATA
_.
END END W~Bo TOTAL
DAY Si02 COND. COND. REGEN. TOTAL RUN
.
47 .011 3 M~1HO 20 ~HO 268,000 1,364,900 Gal.
48 .011 3 15 n 278,1101,319,800
49 . O11 4 n 19 234,0001,467,300 n
.013 6 19 n 227,5001,374,000
51 .011 8 8 286,7001,250,700
52 .011 6 8 286,7001,392,300
53 .011 8 8 a 275,0001,337,200
54 .014 8 21 270,0001,390,560
.017 5 n 18 a 334,6001,445,900
56 .014 9 40 302,7001,347,700 n
57 .011 5 20 307,5001,072,900
58 .006 8 24 K 284,3001,141,500
59 .011 8 26 n 284,8001,101,500
.017 6 ~ 35 ~ 301,0001,148,400
61 .009 8 n 60 ~ 284,1001,246,400
62 .031 12 ~ 30 ~ 274,5001,118,700
63 .020 12 ~ 50 ~ 253,600992,700
64 .017 12 R 26 295,9001,133,600
.011 5 25 286,3001,014,900
66 .014 5 30 295,6001,682,200
67 .020 8 12 427,0001,620,800
68 .017 20 ~ 8 ~ 261,300995,300
69 .009 15 ~ 273,2001,021,600
Average -- 1,215,340
~ lZ184~5
Example 6
Finally, a trial was held at a chemical plant in a
midwestern state of the United States. This plant was operating
two water softeners for its low pressure boiler system, using
standard ion exchange technology. ~un lengths of this plant were
only approximately 51,000 gallons, even though the resin capacity
was greater than 80~ of the initial capacity but less than 90% of
initial capacity.
This field trial was aimed at demonstrating that the
preventive maintenance program itself was capable of restoring,
improving, and maintaining the performance of these
water-treatment solids and ion exchange resins which were fouled
with iron, organic substances, micro-organisms, and
micro-organism waste products.
The operating procedures were not changed in any way
during this plant trial. No batch cleaning of this resin was
completed, but simply a preventive maintenance program was
initiated which comprised cyclically treating the ion exchange
resins within the water softener units in this plant with an
effective amount of the non-ionic surfactant and bio-dispersant
of this invention. This treatment was augmented by the addition
in conjunction with the non-ionic surfactant and bio-dispersant
described above of a quaternary ammonium biocide.
The non-ionic surfactant chosen was again the ethylene
oxide adduct of an alkylated phenol which had an HLB of
approximately 13 - 14. The bio dispersant chosen to complete
these tests consisted of an ethylene oxide condensate with
propylene oxide adducts onto propylene glycol. This
bio-dispersant had a molecular weight between 1500 - 3000 and had
an HLB between 7 - 8.
lZ18475
The resin beds were treated by adding about 20 ppm of
the 1:1 weight ratio of non-ionic surfactant to bio-dispersant
product to the anionic resins contained within this water
softener unit. The addition was made during the first one-third
of the backwash cycle and was followed by a rinsing of the bed
during ~ne next two-thirds of the backwash cycle and subsequently
followed by standard regeneration techniques. The cationic resin
beds were bac~washed using 20 ppm of the above formulation and,
in addition, an effective amount of a quaternary ammonium salt
biocidal compound. Again, the cleaning solution containing the
non-ionic surfactant and bio-dispersant along with the biocide
was added during the first one-third of the backwash cycle, was
followed by a rinsing of cleaning chemicals during the last
two-thirds of the backwash cycle, and was subsequently followed
by standard regeneration chemicals and rinse techniques.
The results indicated that the total run lengths
increased from an initial 51,000 gallons to approximately 69,000
gallons within a two-week period of time. After the first one
month, the run lengths had stabilized at about 69,000 gallons and
was cut back to a constant 63,000 gallon run length to place this
system on an automatic control for the convenience of the
operators of this chemical plant facility. This plant has
operated successfully and continuously at this 63,000 gallon run
length without any indicated loss of resin capacity or ion
splitting capacity for a period of about 6 ~onths.
This last field trial indicates the successful use of
the preventive maintenance program alone without the need for a
prior batch cleaning operation. Such a program prevents
shut-down of the demineralizer train, thereby preventing down
time in the generation of steam and downtime in the operation of
chemical processing plants.
~Z~8~7~
Exampl~ 7
It would be anticipated by this inventor that if a
system went onstream with newly charged fresh ion exchange resin,
and this system was treated in the manner described above with
the preventive maintenance program using the chemicals of this
invention, that this system could be maintained at optimum resin
capacity, optimum salt splitting capacity, and optimum gallon run
lengths for a vastly improved period of time. Such a system
operating with the advantages of this invention would save the
operator considerable monies and costs which would normally be
due to water usage, regenerating chemical usage, operating
downtime, resin replacement costs, and labor costs.
Example 8
A home water softener unit was badly fouled by
accumulated debris, organic contaminants, microbiological growth,
and the waste products therefrom. The home water softener unit
did not have a backwash cycle prior to.regeneration but, instead,
went directly from operation to regeneration, then to a rinse
cycle, then back again into operation.
The formulation of Example 1 was added directly to the
concentrated NaCl brine which was used to regenerate this water
softener unit. Concentrations were about 2000 ppm and normal
regeneration with brine including the chemical formulation of
Example 1 was followed by the normal rinse cycle which removed
the excess brine and any residual chemical. Copius quantities of
accumulated organic, inorganic, and biological debris were
removed from the resin used in this home water so~tener.
Continued treatment during each regeneration and rinse cycle
usir.g from 10 to 200 ppm of formulations including a non-ionic
~X~847~;
surfactant, a non-ionic bio-dispersant, and a fatty quaternary
amine salt biocide maintained the resin in this unit at nearly
original effectiveness.
Example 9
The formulations of Example 8 were found to be only
mildly soluble in the concentrated brine used to regenerate the
home water softener units. To improve resin bed contact with the
formulations of this invention, various coupling agents were
used. These agents included high HLB materials having an HLB
between about 12 and about 30. Specifically, the addition of up
to equal amounts of the following compounds seemed to improve
solubility of the formula of Example 1:
~p1ing Agents
1. Rohm & Haas Triton DF-20, a modified
ethoxylated alcohol;
2. Rohm & Haas Triton X-114, an octyl phenoxy
polyethoxyethanol;
-¦ 3. Westvaco Diacid 1550, a dimer acid.
Addition of the formulas of this invention, coupled wit~
coupling agents similar to or like those listed above, would be
¦ expected to function in a process for improving and maintaining
the performance of water-treatment solids which are, or tend to
become, fouled with organic substances, microbiological growth,
and waste products therefrom. The process should include
cyclically adding these formulations, with or without a coupling
agent as described above, to each regenerant cycle or bacXwash
cycle, if separate, followed by a rinse cycle which would remove
regenerant chemical as well as the formulations of this
invention, including the coupling agents if their use is found
necessary to maintain complete solubility or dispersability in
the regenerant brine solutions.
* Trade Mark
-51-
1~1~34'75
SVMMARY
The treatment of contaminated resins with surfactants
and bio-dispersants will substantially improve the performance
characteristics of resins. When compared to treatments currently
available ~o the industry, the differences in restoring ion
exchange resin performances are quite substantial. In addition,
the new treatment sharply decreases the bacterial growth on the
resin and reduces the likelihood of discharging large amounts of
bacteria into the treated water supply. Physical breakdown of
resins is reduced when particles and bacterial waste products no
longer accumulate and cause excessive pressure drop across the
unit.
The current mode of operating an ion exchange unit is to
allow the unit to operate until it is contaminated and operating
difficulties are too great to continue using the unit. If the
resin cleaning does not show the desired results, the resin is
replaced. This is currently an accepted practice because the
user of ion exchange units has no other choic~.
The present invention provides:
(1) a means of preventing the accumulation of
organic and microbiological foulants by treating freshly
charged resins prior to or during each backwash and
regeneration cycle with the non ionic surfactant and
bio-dispersant of this invention;
(2) a means of improving and maintaining the
performance of these resins using the cyclic treatments
described above; and
(3) recovering lost resin capacity caused by
_ fouling of these resins with organics, micro-organisms,
- and waste products thereof.
!1 -52-
I ~X1~34~Y~
The advantages of such treatment programs include:
(1) the resins can be maintained in good operaing
condition and can be operated at a reasonably low
regenerant and operating cost, and
(2) the buildup of contaminants within a resir. unit
will be kept at a minimum, which reduces the extent of
resin bead breakage. For these reasons, the cost
savings attainable with the present invention can be
substantial. Also, the resin bed will no lon~er provide
excessive amounts of nutrients for bacteria, and the
treated water will be less contaminated with bacteria,
which is an important consideration in cases where the
treated water is used in the food or beverage industry
for drinking water or for pharmaceutical uses.
The use of activated carbon and other adsorbents for the
pretreatment of ion exchange units is an accepted practice.
These are used to remove chlorine, organics, iron, and
miscellaneous particles from the water~prior to an ion exchange
treatment. The use of the present invention has been found to
extend the usefulness of these adsorbents over a longer period of
time and to limit the growth of bacteria.
The applicability of the agents and process of the
present invention is not limited to ion exchange resins or
adsorbents. Other products that accumulate organics, bacteria,
and bacterial waste products such as, for example, reverse
osmosis, ultra-filtration, or dialysis membranes, can be cleaned
and maintained by the subject techniques.
-53-
