Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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HIGHER ACTIVES DISPERSION POLYMER TO AID CLARIFICATION,
DEWATERING, AND RETENTION AND DRAINAGE
Field of Invention
The invention is a method for clarifying industrial
waste water or paper furnish with an effective amount of
at least one dispersion of a water soluble cationic
polymer flocculant wherein the improvement comprises the
addition of said polymer which has a concentration of at
least twenty five percent to said waste water or paper
furnish. The industrial waste is preferably food
processing waste water, oily waste water, paper mill
waste water and inorganic contaminated waste water. The
paper furnish may be an aqueous cellulosic suspension.
Background of the Invention
This invention relates to polymers that are of
particular value as flocculants for suspensions of
organic matter of a proteinaceous or cellulosic nature
such as are to be found in sewage and industrial plant
treatment effluents or in paper mills.
It is commonly accepted that such suspended
materials which are hydrophilic in nature and which often
have specific gravities quite close to that of the
aqueous liquors in which they are suspended, contrast in
a marked way with the more hydrophobic mineral
suspensions in that they are frequently found to be much
more difficult to flocculate economically with chemical
reagents prior to a physical dewatering step such as
filtration, flotation, sedimentation, dewatering or in
the retention of such materials for processing. These
difficulties are particularly noticeable when higher
proportions of suspended matter are present, commonly
involving concentrations of 0.5 percent by weight and
upwards wherein the suspensions take on a paste-like
consistency and are commonly described as sludges or
paper furnishes.
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It is well known that the clarification or
dewatering of sewage and industrial sludges and similar
organic suspensions may be aided with the use of chemical
reagents, added in order to induce a state of coagulation
or flocculation which facilitates the process of
solid/liquid or liquid/liquid separation from water. For
this purpose, lime or salts of iron or aluminum have been
utilized. More recently synthetic polyelectrolytes,
particularly certain cationic copolymers of acrylamide,
have been found to be of interest.
Cationically charged water soluble or water
dispersible polymers are utilized in a variety of
processes that involve the separation of solids or
immiscible liquids dispersed or suspended in water from
water, and the dewatering of solids containing water.
These types of polymers, which may be natural or
synthetic, are broadly termed coagulants and flocculants.
These polymers can be utilized in such diverse processes
as emulsion breaking, sludge dewatering, raw water
clarification, drainage and retention aids in the
manufacture of pulp and paper, flotation aids in mining
processing and color removal.
Polymers of this type generally work by neutralizing
the anionic charge of the suspended solids, or liquids,
which are to be removed. These solids or liquids may be
waste which must be removed from water, or desirable
products which are recovered from aqueous systems, such
as coal fines, which can be coagulated or flocculated and
sold as fuel.
In the water treatment field of solids/liquid
separation, suspended solids are removed from water by a
variety of processes, including sedimentation, straining,
flotation, filtration, coagulation, flocculation, and
emulsion breaking among others. Additionally, after
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suspended solids are removed from the water they must
often be dewatered so that they may be further treated or
properly disposed of. Liquids treated for solids removal
often have as little as several parts per billion of
suspended solids or dispersed oils, or may contain large
amounts of suspended solids or oils. Solids being
dewatered may contain anywhere from 0.25 weight percent
solids, to 40 or 50 weight percent solids material.
Solids/liquid or liquid/liquid separation processes are
designed to remove solids from liquids, or liquids from
liquids.
While strictly mechanical means have been used to
effect solids/liquid separation, modern methods often
rely on mechanical separation techniques which are
augmented by synthetic and natural cationic polymeric
materials to accelerate the rate at which solids can be
removed from water. These processes include the
treatment of raw water with cationic coagulant polymers
which settle suspended inorganic particulates and make
the water usable for industrial or municipal purposes.
Other examples of these processes include the removal of
colored soluble species from paper mill effluent wastes,
the use of organic flocculant polymers to flocculate
industrial and municipal waste materials, sludge
recovery and emulsion breaking.
Regarding the mechanism of separation processes,
particles in nature have either a cationic or anionic
charge. Accordingly, these particles often are removed
by a water soluble coagulant or flocculant polymer having
a charge opposite to that of the particles. This is
referred to as a polyelectrolyte enhanced solids/liquid
separation process, wherein a water soluble or
dispersionable ionically charged polymer is added to
neutralize the charged particles or emulsion droplets to
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be separated. The dosage of these polymers is critical
to the performance of the process. Too little ionically
charged polymer, and the suspended particles will not be
charge neutralized and will thus still repel each other.
Too much polymer, and the polymer will be wasted, or
worse, present a problem in and of itself.
Examples of such cationic polymers for dewatering
include U. S. Patent No. 3,409,546 which describes the
use of N-(amino methyl)-polyacrylamides in conjunction
with other cationic polymers for the treatment of sewage
sludges; U. S. Patent No. 3,414,514 which describes the
use of a copolymer of acrylamide and a quaternized
cationic methacrylate ester, JP 61-106072 which describes
water-soluble copolymers and another class of cationic
polymers used to dewater sludges described in U.S. Patent
No. 3,897,333. Utilization of polyethyleneimines and
homopolymers of cationic acrylates and methacrylates and
other cationic polymers such as polyvinyl pyridines is
also known.
Another example of a cationic polymer useful for
sludge treatment is U. S. Patent No. 4,191,645, in which
cationic copolymers prepared from a nonionic monomer,
such as acrylamide, and a cationic monomer, such as
trimethylammonium ethylmethacrylate methyl sulfate
quaternary (TMAEM.MSQ) or dimethylaminoethylacrylate
methyl sulfate quaternary (DMAEA.MSQ) are disclosed.
Further examples of polymeric treatments for sludge
dewatering include the 1,4-dichloro-2-butene
dimethylamine ionene chloride polymer as disclosed in U.
S. Patent No. 3,928,448 and the block copolymers
disclosed in U. S. Patent No. 5,234,604.
Among treatments useful for improving retention and
drainage are those described in U.S. Patent Nos.
5,126,014 and 5,266,164.
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Notwithstanding the variety of commercially
available polymers which have been found to be capable of
flocculating or coagulating solids sludges, there are
various circumstances which tend to limit the usefulness
of these reagents. While for certain sludges economical
treatments with these known reagents are feasible, more
often sludges require very high and cost-ineffective
dosages of reagents for successful treatment. Moreover,
variations often occur in sludge from any one source.
For example, variations in the supply of material to the
waste water/sludge/paper furnish process water and/or in
the oxidizing conditions that may be involved in the
production of these waters lead to a variety of particle
types which must be removed. Furthermore, it is not
uncommon to encounter sludges which are, for some reason,
not amenable to flocculation by any of the known
polymeric flocculating agents. It is therefore an
object of the invention to provide to the art a superior
method for the dewatering of sludge-containing industrial
waste waters or in the retention of industrial processing
aids.
Summary of the Invention
The invention is a method for clarifying industrial
waste water or paper furnish with an effective amount of
at least one dispersion of a water soluble cationic
polymer flocculant wherein the improvement comprises the
addition of said polymer which has a concentration of at
least twenty five percent to said waste water or paper
furnish. The industrial waste is preferably food
processing waste water, oily waste water, paper mill
waste water and inorganic contaminated waste water. The
paper furnish may be an aqueous cellulosic suspension.
Description of the Invention
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Methods for manufacturing the polymer dispersion used in
the invention are described in detail in U.S. Pat. Nos.
5,006,590 and 4,929,655, assigned to Kyoritsu Yuki Co., Ltd.,
Tokyo, Japan, and U.S. Pat. Nos. 5,708,071 and 5,587,415
assigned to Hymo Corporation of Tokyo, Japan.
This invention represents a substantial improvement in the
art of treatment of aqueous systems with dispersion polymers.
As will be shown in the Examples, the :lower concentration
dispersion polymers presently utilized and disclosed are
inferior to those dispersion polymers at higher concentrations
disclosed herein. The superiority of the polymers disclosed
herein is much more than an incremental additive effect which
would be normally expected by those skilled in the art. The
Examples will illustrate this unexpectedly greater activity at
much lower dosage, which was previously unforeseeable.
The Monomers
According to the invention, the polymer dispersion used to treat
the produced water is prepared from a water-soluble monomer
mixture containing at least 5 mole % of a cationic monomer
represented by the general formula (I):
R2 R3
Z
N(D
B,
p
wherein R1 is H or CH3; R2 and R3 are each an alkyl group having 1
to 2 carbon atoms; A1 is an oxygen atom or NH; B1
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is an alkyl group having 2 to 4 carbon atoms or a
hydroxypropyl group and X1 is a counter anion. The above
water-soluble monomer mixture is soluble in the aqueous
solution of the anionic salt. The polymer generated from
the monomer mixture is, however, insoluble in the aqueous
anionic salt solution. The polymer of the monomer
mixture can also be used as the seed polymer. The seed
polymer is described in detail below.
The above cationic monomer represented by the
general formula (I) preferably is a quaternary ammonium
salt obtained by the reaction of benzyl chloride and
dimethylaminoethyl acrylate, diethylaminoethyl acrylate,
dimethylaminohydroxypropyl acrylate, dimethylaminopropyl
acrylamide, dimethylaminoethyl methacrylate,
dimethylaminoethyl methacrylate, diethylaminoethyl
methacrylate and dimethylaminopropyl methacrylamide.
Monomers preferably copolymerized with the cationic
monomer represented by the general formula (I) includes
acrylamide, methacrylamide or other N-substituted
(meth)acrylamides and the cationic monomers represented
by the general formula (II):
R5 R6
R4
A2\ /X &I"
2 B2 R7
0 zz
wherein R4 is H or CH3; R5 and R6 are each an alkyl group
having 1 to 2 carbon atoms; R7 is H or an alkyl group
having 1 to 2 carbon atoms; A2 is an oxygen atom or NH; B2
is an alkyl group having 2 to 4 carbon atoms or a
hydroxypropyl group and X2 is a counter anion. X1 and X2
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may be anionic counterions such as halides,
pseudohalides, -S030CH3r and -OC(O)CH3 among others.
Preferable monomers represented by the formula (II)
include the ammonium salts of dimethylaminoethyl
acrylate, diethylaminoethyl acrylate, dimethylaminopropyl
acrylamide, diethylaminopropyl acrylamide and
dimethylhydroxypropyl acrylate, dimethylaminoethyl
methacrylate, diethylaminoethyl methacrylate,
dimethylaminopropyl methacrylamide, diethylaminopropyl
methacrylamide and dimethylhydroxypropyl methacrylate or
other N-substituted (meth)acrylamides as well as the
methylated and ethylated quaternary salts. Among the
more preferable cationic monomers represented by the
general formula (II) are the salts and methylated
quaternary salts of dialkylaminoethyl acrylate and
dialkylaminoethyl methacrylate. The concentration of the
above-mentioned monomers in the polymerization reaction
mixture is suitably in the range of 5 to 30% by weight.
The Anionic Salts
The anionic salt to be incorporated in the aqueous
solution according to the present invention is suitably a
sulfate, a phosphate, a chloride or a mixture thereof.
Preferable salts include ammonium sulfate, sodium
sulfate, magnesium sulfate, aluminum sulfate, ammonium
chloride, sodium chloride, ammonium hydrogen phosphate,
sodium hydrogen phosphate and potassium hydrogen
phosphate. In the present invention, these salts may be
each used as an aqueous solution thereof having a
combined concentration of 10% or above.
The Dispersants
A dispersant polymer (also referred to as stabilizer
polymer) is present in the aqueous anionic salt solution
in which the polymerization of the above monomers occurs.
The dispersant polymer is a water-soluble high molecular
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weight cationic polymer. The dispersant polymer is at
least partially soluble in the above-mentioned aqueous
salt solution. The dispersant polymer is preferably used
in an amount of from 1 to 10% by weight based on the
total weight of the monomers. The dispersant polymer is
composed of 5 mole % or more of a diallyldialkyl ammonium
halide or of a cationic monomer unit represented by the
formula I or II. Preferably, the residual mole % is
acrylamide or methacrylamide or other N-substituted
(meth)acrylamides or diallyldimethyl ammonium chloride.
The performance of the dispersant is not greatly affected
by molecular weight. However, the molecular weight of
the dispersant is preferably in the range of 10,000 to
10,000,000. According to one embodiment of the
invention, a multifunctional alcohol such as glycerin or
polyethylene glycol or a chain transfer agent such as
sodium formate is coexistent in the polymerization
system. The deposition of the fine particles is smoothly
carried out in the presence of these agents.
The Dispersion Polymers
For the polymerizations, a usual water-soluble
radical-forming agent can be employed, but preferably
water-soluble azo compounds such as 2,2'-azobis(2-
amidinopropane) hydrochloride and 2,2'-azobis(N,N'-
dimethyleneisobutylamine) hydrochloride are used.
According to one embodiment of the invention, a seed
polymer may be added before the beginning of the
polymerization of the above monomers for the purpose of
obtaining a fine dispersion. The seed polymer is a
water-soluble cationic polymer insoluble in the aqueous
solution of the anionic salt. The seed polymer is
preferably a polymer prepared from the above monomer
mixture by the process described herein. Nevertheless,
the monomer composition ofthe seed polymer need not
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always be equal to that of the water-soluble cationic
polymer formed during polymerization. However, like the
water-soluble polymer formed during polymerization, the
seed polymer should contain at least 5 mole percent of
cationic monomer units represented by the general formula
(I). According to one embodiment of the invention, the
seed polymer used in one polymerization reaction is the
water-soluble polymer prepared in a previous reaction
which used the same monomer mixture.
One aspect of this invention is a method for
clarifying waste water with an effective clarifying
amount of at least one dispersion of a water soluble
cationic polymer flocculant; wherein said water soluble
flocculant is added to said waste water in an effective
amount to flocculate suspended solids, the suspended
solids are removed, and a clarified water is obtained,
said dispersion of said water soluble cationic polymer
flocculant formed from polymerizing vinylic monomers
under free-radical forming conditions in a medium
containing water, monomers, stabilizer polymer, and an
aqueous anionic salt solution; wherein said water-soluble
cationic polymer flocculant is polymerized from
a) at least 5 mole % of a cationic monomer selected
from the group consisting of: monomers of general
formula (I)
R2 R3 ~
R1
ND
/~~
B,
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wherein Rlis selected from the group consisting of H
and CH3r R2 and R3 are selected from the group
consisting of C1 alkyl and C2 alkyl, A1 is
selected from the group consisting of 0 and NH, B1 is
selected from the group consisting of C2
alkyl, C3 alkyl and hydropropoxy groups, and X1- is
an anionic counterion and
monomers of general formula II:
R5 R6
R4
A /x~Z
R7
B2
zz
wherein R4 is selected from the group consisting of
H and CH3r R5 and R6 are selected from the group
consisting of C1 alkyl and C2 alkyl; R7 is selected
from the group consisting of hydrogen atom, C1 alkyl
and C2 alkyl; A2 is selected from the group
consisting of an oxygen atom and NH; B2 is selected
from the group consisting of C2 alkyl, C3 alkyl, C9
alkyl and hydroxypropyl and X2 - is an anionic
counterion with
b) at least 5 mole % of a monomer selected from the
group consisting of C1-Clo N-alkyl acrylamide, C1-Clo N,N-
dialkyl arylamide, C1-Clo N-alkylmethacrylamide, C1-Clo
N,N-dialkylmethacrylamide, N-aryl acrylamide, N,N-diaryl
acrylamide, N-aryl methacrylamide, N,N-diaryl
methacrylamide, N-arylalkyl acrylamide, N,N-diarylalkyl
acrylamide, N-arylalkyl methacrylamide, N,N-diarylalkyl
methacrylamide, acrylamide and methacrylamide;
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and wherein said stabilizer polymer is a cationic
polymer which is at least partially soluble in said
aqueous solution of said anionic salt, wherein the
improvement comprises the addition of said water-
soluble cationic flocculant polymer dispersion to
said waste water at a concentration of at least
twenty-five weight percent polymer dispersion in
water.
Another aspect of this invention is a method for
dewatering waste water with an effective dewatering
amount of at least one dispersion of a water soluble
cationic polymer flocculant; wherein said water soluble
flocculant is added to said waste water in an effective
amount to dewater suspended solids, the suspended solids
are removed, and a clarified water is obtained, said
dispersion of said water soluble cationic polymer
flocculant formed from polymerizing vinylic monomers
under free-radical forming conditions in a medium
containing water, monomers, stabilizer polymer, and an
aqueous anionic salt solution; wherein said water-soluble
cationic polymer flocculant is polymerized from
a) at least 5 mole % of a cationic monomer selected
from the group consisting of monomers:
of general formula I
R2 R3 ~
R,
N~
Al /xl
B1
O
wherein R1 is selected from the group consisting of H
and CH3r R2 and R3 are selected from the group
consisting of C1 alkyl and C2 alkyl, A1 is
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selected from the group consisting of 0 and NH, B1 is
selected from the group consisting of C2
alkyl, C3 alkyl and hydropropoxy groups, and X1- is
an anionic counterion and
monomers of general formula II:
R5 R6
~ Z
(D
A2 /~~' \
2 R7
B2
O II
wherein R4 is selected from the group consisting of
H and CH3, R5 and R6 are selected from the group
consisting of C1 alkyl and C2 alkyl; R7 is selected
from the group consisting of hydrogen atom, C1 alkyl
and C2 alkyl; A2 is selected from the group
consisting of an oxygen atom and NH; B2 is selected
from the group consisting of C2 alkyl, C3 alkyl, C4
alkyl and hydroxypropyl and X2 - is an anionic
counterion with
b) at least 5 mole % of a monomer selected from the
group consisting of CI-CIo N-alkyl acrylamide, CI-Clo N, N-
dialkyl arylamide, C1-Clo N-alkylmethacrylamide, CI-CIo
N,N-dialkylmethacrylamide, N-aryl acrylamide, N,N-diaryl
acrylamide, N-aryl methacrylamide, N,N-diaryl
methacrylamide, N-arylalkyl acrylamide, N,N-diarylalkyl
acrylamide, N-arylalkyl methacrylamide, N,N-diarylalkyl
methacrylamide, acrylamide and methacrylamide;
and wherein said stabilizer polymer is a cationic
polymer which is at least partially soluble in said
aqueous solution of said anionic salt; wherein the
improvement comprises the addition of said water-
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soluble cationic flocculant polymer dispersion to
said waste water at a concentration of at least
twenty-five weight percent polymer dispersion in
water.
Yet another aspect of this invention is a method for
improving retention and drainage of process water in pulp
and paper production with an effective amount of at least
one dispersion of a water soluble cationic polymer
flocculant; wherein said water soluble flocculant is added
to said process water in an effective amount to improve
retention and drainage, said dispersion of said water
soluble cationic polymer flocculant formed from
polymerizing vinylic monomers under free-radical forming
conditions in a medium containing water, monomers,
stabilizer polymer, and an aqueous anionic salt solution;
wherein said water-soluble cationic polymer flocculant is
polymerized from
a) at least 5 mole % of a cationic monomer selected
from the group consisting of: monomers of general formula
I
R2 R3 ~
R1
NO
al\ /Xo /
B,
o
wherein R1 is selected from the group consisting of H
and CH3, R2 and R3 are selected from the group consisting
of C1 alkyl and C2 alkyl, A1 is selected from the group
consisting of 0 and NH, B1 is selected from the group
consisting of CZ alkyl, C3 alkyl and hydropropoxy groups,
and X1- is an anionic counterion and
monomers of general formula II:
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R5 R6
R4 \ /
(D
A2 /~:" \
' Z R7
BZ
O II
wherein R4 is selected from the group consisting of
H and CH3, R5 and R6 are selected from the group
consisting of C1 alkyl and C2 alkyl; R7 is selected
from the group consisting of hydrogen atom, C1 alkyl
and C2 alkyl; A2 is selected from the group
consisting of an oxygen atom and NH; B2 is selected
from the group consisting of C2 alkyl, C3 alkyl, C4
alkyl and hydroxypropyl and X2- is an anionic
counterion with
b) at least 5 mole % of a monomer selected from the
group consisting of C1-Clo N-alkyl acrylamide, C1-Clo N,N-
dialkyl arylamide, C1-
Clo N-alkylmethacrylamide, C1-Clo N,N-
dialkylmethacrylamide, N-aryl acrylamide, N,N-diaryl
acrylamide, N-aryl methacrylamide, N,N-diaryl
methacrylamide, N-arylalkyl acrylamide, N,N-diarylalkyl
acrylamide, N-arylalkyl methacrylamide, N,N-diarylalkyl
methacrylamide, acrylamide and methacrylamide;
and wherein said stabilizer polymer is a cationic
polymer which is at least partially soluble in said
aqueous solution of said anionic salt; wherein the
improvement comprises the addition of said water-
soluble cationic flocculant polymer dispersion to
said waste water at a concentration of at least
twenty-five weight percent polymer dispersion in
water.
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Preferred polymeric flocculants are
poly(DMAEA.MCQ/AcAm), poly(DMAEA.BCQ/AcAm) and
poly(DMAEA.MCQ/DMAEA.BCQ/AcAm).
For any aspect of this invention, a stabilizer polymer
may be polymerized from at least 5 mole % of cationic
monomers selected from the group consisting of monomers
of general formula I
R2 R3 ~
R1
N(D
A, /xl
B,
0
wherein R1 is selected from the group consisting of H and
CH3, R2 and R3 are selected from the group consisting of C1
alkyl and C2 alkyl, A1 is selected from the group
consisting of 0 and NH, B1 is selected from the group
consisting of C2 alkyl, C3 alkyl and hydropropoxy groups,
and X1- is an anionic counterion; diallyl dialkyl ammonium
halides and monomers of general formula II:
R5 R6
R4
A2 / 2- R7
B2
wherein R4 is selected from the group consisting of H and
CH3r R5 and R6 are selected from the group consisting of C.
alkyl and C2 alkyl; R7 is selected from the group
consisting of hydrogen atom, C1 alkyl and C2 alkyl; A2 is
selected from the group consisting of an oxygen atom and
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NH; B2 is selected from the group consisting of C2 alkyl,
C3 alkyl, C4 alkyl and hydroxypropyl and X2- is an anionic
counterion. A preferred diallyl dialkyl ammonium halide
is diallyl dimethyl ammonium chloride (DADMAC).
The waste water may be selected from the group
consisting of industrial wastewater and municipal
wastewater. Moreover, the industrial wastewater may be
selected from the group consisting of food processing
waste water, oily waste water, paper mill waste water and
inorganic-contaminated waste water. The polymers
described herein may be used in conjunction with
coagulants such as poly(DADMAC),
poly(epichlorohydrin/dimethylamine) and inorganic
materials among others.
The polymers of this invention were compared to
polymers which were manufactured by the Derypol S.A.
Corporation of Spain. The polymer preparations are
available from Derypol S.A. Corporation under the trade
name designations DR-2570 (sold at 15% concentration),
DR-3000 and DR-4000 (both of which are sold at 20%
concentrations).
The following examples are presented to describe
preferred embodiments and utilities of the invention and
are not meant to limit the invention unless otherwise
stated in the claims appended hereto.
Example 1
A 25% polymer solids, 65/25/10 mole percent
AcAm/DMAEA. BCQ/DMAEA. MCQ dispersion was synthesized in
the following manner. A 1500cc reaction flask was fitted
with a mechanical stirrer, thermocouple, condenser,
nitrogen purge tube, addition port, and heating tape. To
this reactor was added 173.7g of acrylamide=(50o aqueous
solution, available from Nalco Chemical Co. of
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Naperville, IL), 158.5g of dimethylaminoethyl acrylate
benzyl chloride quaternary salt (80% aqueous solution,
available from Nalco Chemical Co. of Naperville, IL),
45.5g of dimethylaminoethyl acrylate methyl chloride
quaternary salt (80% aqueous, available from CPS Chemical
Company of Old Bridge, N.Y.), 18.8g of glycerin, 45.9g of
the homopolymer of dimethylaminoethyl acrylate methyl
chloride quaternary (20% aqueous solution, available from
Nalco Chemical Co. of Naperville, IL), 16.7g of a
copolymer of diallyldimethylammonium chloride and
dimethylaminoethyl acrylate benzyl chloride quaternary
(15% aqueous solution, available from Nalco Chemical Co.
of Naperville, IL), 1.5g of a 1.0% aqueous solution of
sodium bisulfite, 0.5g of sodium diethylene triamine
pentaacetate (DABERSEEN 503 available from Derypol S.A.
of Spain, 45% aqueous solution), 135.Og of ammonium
sulfate, and 332.3g of deionized water. The mixture was
then heated to 35 C under a constant nitrogen purge while
stirring at 90 rpm. After reaching 35 C and under a
constant purge of nitrogen, 3.7g of a 1.0% aqueous
solution of 2,2'-azobis(N,N'-dimethyleneisobutyramidine)
dihydrochloride (WAKO VA-044 available from Wako
Chemicals of Dallas, TX) was added to the reaction
mixture and the temperature was maintained for
approximately 16 hours. The temperature was then
increased to 50 C and 1.5g of a 10% aqueous solution of
ammonium persulfate and 1.5g of a 10% aqueous solution of
sodium bisulfite were added. The temperature was
maintained for one hour, cooled to ambient temperature,
and 45.Og of ammonium sulfate, 10.Og sodium thiosulfate,
and lO.Og acetic acid were added. The final product was
a smooth milky white dispersion with a bulk viscosity of
1950 cps. Upon dilution to 0.5% active polymer, a
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solution viscosity of 74 cps in 2% aqueous ammonium
sulfate was obtained.
Example 2
To determine the increased effectiveness of the
higher polymer solids polymer synthesized according to
the procedure of Example 1 at improving the clarity of
the waste water, jar tests were performed at an animal
food production facility. 200 ml snatch samples of
untreated effluents were taken from a sump in the
facility prior to the reception pit. The appropriate
amount of polymer was added to the sample at a pH of 7.1.
The solution was mixed 5 seconds vigorously, then slowly
for 30 seconds.
The clarity of the supernatant was determined by a
visual evaluation with values assigned from 1 to 10,
where 10 is the most free of solids and is most
desirable. Floc size is also based on a visual
evaluation, wherein a larger floc (higher number) is more
desirable.
Table I illustrates the results of the comparison
between Polymer A(20o actives dispersion polymer DR-
3000, available from Derypol S.A. Corporation of Spain)
and Polymer B(25o actives dispersion polymer,
synthesized according to the procedure described in
Example 1). The molecular weights of the two polymers
were considered to be equal based on the fact that
Polymer A and Polymer B had equivalent reduced specific
viscosity measurement values as recorded in 0.125N NaN03
solutions.
The dosages of the products in Table I were adjusted
to an equal polymer actives basis. Normally one would
expect an equal performance on an actives basis since the
polymers are of the same chemical composition and
CA 02368604 2001-09-21
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molecular weight, but in this case, increased
effectiveness and efficiency were evident with Polymer B
of this invention, above that obtained with commercially
available Polymer A. Superior floc size and water
clarity were obtained with Polymer B compared to Polymer
A, thus a significantly lower treatment dosage can be
utilized.
The surprising results were obtained at 25%
concentration values. One skilled in the art, cognizant
of this surprisingly great result would thereafter
understand that a even higher concentrations should also
produce this augmented effect.
TABLE I
Treatment Dosage (ppm) Floc size Supernate
clarity3
Polymer A 2 5 5
Polymer A 3 6 6
Polymer A 4 7 7
Polymer A 5 7.5 7.5
Polymer A 6 8 8
Polymer B 2.5 7 7
Polymer B 3 8 8
Polymer B 3.75 9 9
Polymer B 5 9 9
Polymer B 6.25 9 9
Polymer A = 20% actives dispersion polymer DR-3000, available
from Derypol S. A. Corporation of Spain
Polymer B = 25% actives dispersion polymer, synthesized
according to the procedure described in Example 1
1 = dosage of polymer listed on an equal actives basis
2 = scale of 1-10, with 10 most desirable as it represents
greatest floc size
3 = scale of 1-10, with 10 most desirable as it represents the
highest clarity
Example 3
A comparison of the polymers synthesized according
to the procedure of Example 1 was also made for
effectiveness as a treatment for the purposes of sludge
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21
dewatering on a twin belt press of a food production
facility.
Polymer A and Polymer B were fed into the food
processing waste water stream using a NALMAT dosing
system (available from Nalco Chemical Co., Naperville,
IL.) which was previously used for trials with latex
polymers. An initial dilution was carried out and the
polymer was prepared as a diluted solution. The solution
of Polymer B had to be prepared at a lower concentration
than Polymer A due to the much higher Brookfield
viscosity. A primary diluted polymer was initially
prepared with the NALMAT dosing system followed by a
secondary dilution with a static mixer in order to reach
a lower concentration. The two dilution strengths are
indicated in Table II's results.
The turbidity of the filtrate released from the belt
filter press was measured with a Hach DR-2000
spectrophotometer. The lower the turbidity reading, the
better the polymers' performance. The cake solids (final
sludge at the outlet of the belt filter press) were
determined gravimetrically according to standard
procedures. The higher the cake solids are, the more
effective the treatment was in dewatering the removed
solids waste water (or sludge). Cake solids can be
artificially high when the performance of the polymer is
poor and a significant amount of solids is squeezed out
of the machine. Therefore the overall performance of the
polymer must be considered. Since the performance of a
belt press is very much based on visual evaluation, the
following parameters were observed: floc size and shape;
free-drainage zone clarity; wedge zone sludge stability
(squeezing); and press zone stability (which includes
cake stickiness and mat characteristics).
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22
These results are shown in Table II. Improved
performance was obtained with Polymer B, above the
commercially available Polymer A. As a result of
treatment with Polymer B, the cake solids were similar to
Polymer A. However, with Polymer B overall quality was
very good, the belt was free of blinding (i.e. - plugged
belt) and the clarity of the filtrate was superior at a
lower dosage when compared to Polymer A. As in Example
2, one would normally expect an equal performance on an
actives basis since the polymers are of the same chemical
composition and molecular weight. However, increased
effectiveness and efficiency were evident with Polymer B
of this invention above that obtained with the
commercially available Polymer A.
TABLE II
Treatment Dosage Solution Visual Cake TurbiditY4
(ppm) Strength2 Performance Solids3($) (NTU)
(%)
Polymer A 56 0.4/0.16 Overdosed N/A 267
Polymer A 34 0.4/0.16 Overdosed 20.7 269
Polymer A 24 0.4/0.16 Good 21 242
Polymer A 22 0.4/0.16 Lower limit 18.6 277
Polymer A 20 0.4/0.16 Underdosed N/A N/A
Polymer B 33.4 0.18/0.04 Good-still 19.2 175
overdosed
Polymer B 26 0.18/0.04 Very good 19.7 262
Polymer B 21.25 0.18/0.06 Excellent 20.8 217
Polymer B 14.25 0.14/0.03 Very good 18 131
N/A = not available
Polymer A 20% actives dispersion polymer DR-3000, available
from Derypol S. A. Corporation of Spain
Polymer B = 25% actives dispersion polymer, synthesized
according to the procedure described in Example 1
1 = dosage of polymer listed on an equal actives basis
2 = listed as solution concentration of active polymer. The
first number represents the primary dilution, the second
number represents the secondary dilution
3 = higher percentages of cake solids are more desirable
4 = lower turbidity is more desirable
Example 4
The polymers synthesized according to the procedure
of Example 1 were also compared as to their abilities to
CA 02368604 2001-09-21
WO 00/61501 PCTIUS99/07916
23
dewater sludge during centrifugation from oily, grease-
containing wastewater at a wastewater disposal facility.
Polymer A and Polymer B were fed in-line using a
Gear pump. With this type of set-up, a change in dosage
would automatically lead to a change in the solution
strength as shown in Table III.
The centrate (outlet water from the centrifuge)
clarity and cake quality were compared qualitatively on a
visual basis and the results are summarized in Table III.
Very good performance was obtained with both polymers,
but that of Polymer B was superior.
For Table III, the lower the value for the centrate
clarity, the better the performance of the polymer. Even
though the centrate clarity was equal between the two
polymers at equal dosage, Polymer B was superior due to
the higher cake quality (drier cake, less sticky, more
compact) across the dosage range. In this Example, as
with the previous examples, one would normally expect an
equal performance on an actives basis since the polymers
are of the same chemical composition and molecular
weight. Table III indicates that increased effectiveness
and efficiency were evident with Polymer B of this
invention, above that obtained with the commercially
available Polymer A.
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24
TABLE III
Treatment Dosage' Solution Centrate Cake
(ppm) Strength2 Clarity3 Solids
M
Polymer A 71 0.24 1 OK
Polymer A 58 0.20 2 OK
Polymer A 45 0.15 3 OK
Polymer B 91 0.2 0 better
Polymer B 68 0.15 1 than with
Polymer B 58 0.13 2 Polymer A
Polymer A = 20% actives dispersion polymer DR-3000, available
from Derypol S. A. Corporation of Spain
Polymer B = 25% actives dispersion polymer, synthesized
according to the procedure described in Example 1
1 = dosage of polymer listed on an equal actives basis
2 = listed as solution concentration of active polymer
3 = scale of 0-3, 0 represents highest water clarity and is
most desirable
Example 5
The polymers synthesized according to the procedure
of Example 1 were also compared as to their abilities to
dewater sludge composed of inorganic contaminated soils
from railways. A procedure similar to that of Example 2
was utilized to obtain the results of Table IV.
The dosage of the polymers in Table IV were adjusted
to an equal polymer actives basis. The performance of
the polymers was evaluated in terms of floc size (the
largest floc size is most desirable), sludge settling
rate ( a faster settling rate is more desirable), floc
stability towards shear (stronger resistance to shear is
more desirable) and drainage rate (highest volume of
water drained is most desirable). Though one would
normally expect an equal performance on an actives basis
since the polymers are of the same chemical composition
and molecular weight, Table IV shows that increased
effectiveness and efficiency were evident with Polymer B
above that obtained with commercially available Polymer
A.
CA 02368604 2001-09-21
WO 00/61501 PCT/US99/07916
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CA 02368604 2001-09-21
WO 00/61501 PCT/US99/07916
26
Example 6
The polymers synthesized according to the procedure
of Example 1 were also compared as to their retention and
drainage capabilities at a recycled board mill.
Both Polymer A and Polymer B were fed directly in
line prior to the pressure screen. A simple static mixer
was used to prepare the polymer solution. No aging tank
was required.
The performance of the two polymers was evaluated by
measuring the First Pass Retention (FPR). FPR is a
measure of the amount of fibers, fines and fillers which
are retained in the paper sheet and is calculated by the
following equation:
% FPR = [(A-B)/A] x 100
A = concentration of the headbox furnish (g/1)
B = concentration of the whitewater (i.e. filtrate) (g/1)
It is desirable to have as high a % FPR as possible.
As clearly demonstrated in Table V, Polymer B was more
efficient than Polymer A since a significantly lower
dosage of Polymer B was required in order to achieve
equal % FPR to that obtained by use of Polymer A. Again
one would normally expect an equal performance on an
actives basis since the polymers are of the same chemical
composition and molecular weight, but in this case
increased efficiency was evident with Polymer B of this
invention, above that obtained with the commercially
available Polymer A.
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WO 00/61501 PCT/US99/07916
27
TABLE V
Total Retention FPR (~)
Treatment Dosage2 (kg/t)
Polymer A 37 0.15
Polymer A 54 0.3
Polymer A 50 0.3
Polymer B 48 0.13
Polymer B 48 0.13
Polymer B 52 0.19
Polymer A = 20% actives dispersion polymer DR-3000, available
from Derypol S. A. Corporation of Spain
Polymer B = 25% actives dispersion polymer, synthesized
according to the procedure described in Example 1
1 = higher percentages of first pass retention are desired
2 = dosage of polymer listed on an equal actives basis
Example 7
The polymers synthesized according to the methods of
Example 1 were also compared in their ability to dewater
oily sludge from a refinery. A sludge sample was
collected prior to the twin belt press used for
dewatering. The polymers were evaluated using a free-
drainage test carried out in the following way: The
desired amount of polymer was added to 200 mL of sludge
and mixed with 10 inversions using graduated cylinders.
The test loading was poured into a pipe resting on top of
a filter cloth and timing was started immediately. The
free drainage volume obtained after 10 seconds was
recorded.
The results are shown in Table VI where drainage
volume at 10 seconds is given. The higher the volume
drained, the more effective is dewatering. As clearly
shown in Table IV, Polymer B outperformed Polymer A on an
actives basis, for polymer B is both more effective
(higher volume drained) and more efficient (less dosage
required). Again one would normally expect an equal
performance on an actives basis since the polymers are of
CA 02368604 2001-09-21
WO 00/61501 PCT/US99/07916
28
the same chemical composition and molecular weight, but
in this case increased efficiency was evident with
Polymer B of this invention, above that obtained with the
commercially available Polymer A.
TABLE VI
Treatment Dosage Drainage Volume2 (mL)
(ppm) at 10 sec.
Polymer A 80 68
Polymer A 100 96
Polymer A 125 96
Polymer A 140 96
Polymer B 75 95
Polymer B 87.5 107
Polymer B 100 108
Polymer B 112.5 108
Polymer B 125 95
Polymer A 20% actives dispersion polymer DR-3000,
available from Derypol S. A. of Spain.
Polymer B = 25% actives dispersion polymer, synthesized
according to the procedure described in Example 1.
1 = dosage of polymer listed on an equal actives basis
2 = higher drainage is more desirable
Changes can be made in the composition, operation
and arrangement of the method of the present invention
described herein without departing from the concept and
scope of the invention as defined in the following
claims:
