MXPA01010035A - Higher actives dispersion polymer to aid clarification, dewatering, and retention and drainage - Google Patents

Abstract

The invention is a method for clarifying, dewatering or improving retention and drainage of 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

POLYMER IN DISPERSION WITH HIGHER ASSET CONCENTRATION TO ASSIST IN CLARIFICATION, DEHYDRATION, AND RETENTION AND DRAINAGE FIELD OF THE INVENTION The invention is a method for clarifying industrial wastewater or paper pulps with an effective amount of at least one dispersion of a water-soluble cationic polymer flocculant wherein the improvement comprises the addition of the polymer having a concentration of at least twenty-five percent to wastewater or paper pulp. Industrial waste is preferably wastewater from food processing, oily wastewater, wastewater from paper mills and wastewater contaminated with inorganic materials. The pulp may be an aqueous cellulosic suspension.

BACKGROUND PE THE INVENTION This invention relates to polymers that have particular value as flocculants for suspensions of REF: 133351 organic matter of a proteinaceous or cellulose nature such as those found in wastewater treatment effluents and industrial plants or in paper mills. It is commonly accepted that these suspended materials which are hydrophilic in nature and which usually have specific gravities quite close to those of the aqueous liquids in which they are suspended, contrast markedly with the more hydrophobic mineral suspensions because they are frequently found to be much more difficult to flocculate economically with chemical reagents prior to a physical dehydration step such as filtration, flotation, sedimentation, dehydration or in the retention of such materials for processing. These difficulties are particularly noticeable when higher proportions of suspended matter are present, commonly including concentrations of 0.5 weight percent and more, where the suspensions adopt a paste-like consistency and are typically described as slurries or paper pulps. It is well known that the clarification or dehydration of wastewater and industrial sludge and similar organic suspensions can be aided by the use of chemical reagents, aggregates to induce a state of coagulation or flocculation that facilitates the separation process of solids / liquids or liquids. water liquids. For this purpose lime or salts of iron and aluminum have been used. More recently, synthetic polyelectrolytes, particularly certain cationic acrylamide copolymers, have been found interesting. Water-soluble or water-dispersible cationically charged polymers are used in a variety of processes including the separation of immiscible solids or immiscible liquids dispersed or suspended in water from water, and the dehydration of solids containing water. These types of polymers, which can be natural or synthetic, are widely called coagulants and flocculants. These polymers can be used in such diverse processes as emulsion breaking, sludge dewatering, natural water clarification, drainage and retention aids in pulp and paper manufacturing, 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 going to be removed. These solids or liquids can be waste or debris that must be removed from water, or desirable products that are recovered from aqueous systems, such as fine particles of carbon, which can be coagulated or flocculated and sold as fuel. In the field of solid / liquid separation of water treatment, suspended solids are removed from the water by means of a variety of processes, including sedimentation, collation, flotation, filtration, coagulation, flocculation and emulsion breakage among others. In addition, after the suspended solids are removed from the water they must commonly be dehydrated so that they can be further treated or disposed of properly. Liquids treated for the removal of solids commonly have as little as several parts per billion suspended solids or dispersed oils, or they may contain large amounts of suspended solids or oils. The solids that are dehydrated can contain any amount from 0.25 weight percent solids, up to 40 or 50 weight percent solids material. Solid / liquid or liquid / liquid separation processes are designed to remove solids from liquids, or liquids from liquids.

Although strictly mechanical means have been used to carry out the separation of solids / liquids, modern methods are usually based on mechanical separation techniques which are augmented by synthetic or natural cationic polymeric materials to accelerate the rate at which solids can be removed from the water These processes include the treatment of natural water with cationic coagulant polymers that sediment suspended inorganic particles and render the water usable for industrial or municipal purposes. Other examples of these processes include the removal of colored soluble species from wastewater effluent from paper mills, the use of organic flocculating polymers to flocculate waste materials or industrial and municipal waste, mud recovery and emulsion breakage. In reference to the mechanism of the separation processes, the particles have in nature a cationic or anionic charge. Accordingly, these particles are commonly removed by means of a water-soluble coagulating or flocculating polymer having a charge opposite to that of the particles. This is known as a solid / liquid separation process enriched with polyelectrolytes, in which an ionically charged polymer soluble or dispersible in water is added to neutralize the charged particles or cause the emulsion droplets to be separated. The dosage of these polymers is critical for the performance and performance of the process. Very little ionically charged polymer, and the charge of the suspended particles will not be neutralized and in this way they will still repel each other. Too much polymer, and the polymer will be wasted, or worse, it will present a problem in and of itself. Examples of these cationic polymers for dehydration include the U.S.A. No. 3,409,546, which describes the use of N- (aminomethyl) -polyacrylamides in conjunction with other cationic polymers for the treatment of sewage sludge; the patent of E.U.A. No. 3,414,514, which discloses the use of an acrylamide copolymer and a quaternized cationic methacrylate ester; JP 61-106072, which discloses water-soluble copolymers or another class of cationic polymers used to dehydrate slurries described in the U.S.A. No. 3,897,333. It is also known to use polyethyleneimines and homopolymers of cationic acrylates and methacrylates and other cationic polymers such as polyvinylpyridines.

Another example of a cationic polymer useful for the treatment of sludge is the patent of E.U.A. No. 4,191,645, in which cationic copolymers prepared from a nonionic monomer, such as acrylamide, and a cationic monomer, such as trimethyl ammonium ethyl methacrylate quaternary methylsulfate (TMAEM.MSQ) or dimethylaminoethylacrylate quaternary methylsulfate (DMAEA. MSQ). Additional examples of polymeric treatments for sludge dewatering include the ionene-2-butene dimethylamine ionene chloride polymer as described in the U.S.A. No. 3,928,448 and the block copolymers described in the U.S.A. No. 5,234,604. Among the treatments useful to improve retention and drainage are those described in the patents of E.U.A. Nos. 5,126,014 and 5,266,164. Despite the variety of commercially available polymers that have been found capable of flocculating or coagulating sludge with solids, there are different circumstances that tend to limit the usefulness of these reagents. Although economic treatments with these reagents are possible for certain sludge, sludge most often requires very high and expensive doses of reagents useful for successful treatment. Moreover, variations in mud from any other source commonly occur. For example, variations in the supply of material to the water from the wastewater / sludge / pulp process and / or in the oxidation conditions that may be involved in the production of this water lead to a variety of types of particles that must be removed. furtherIt is not uncommon to find sludge that is, for some reason, unfavorable to flocculation by any of the known polymeric flocculation agents. It is therefore an object of the invention to provide the art with a superior method for the dehydration of industrial wastewater containing sludge or in the retention of industrial processing aids.

BRIEF DESCRIPTION OF THE INVENTION The invention is a method for clarifying industrial wastewater or paper pulps with an effective amount of at least one dispersion of a water-soluble cationic polymer flocculant wherein the improvement comprises the addition of the polymer having a concentration of at least twenty-five percent to wastewater or paper pulp. Industrial waste is preferably wastewater from food processing, oily wastewater, wastewater from paper mills and wastewater contaminated with inorganic materials. The pulp may be an aqueous cellulosic suspension.

DESCRIPTION OF THE INVENTION The methods for making the polymer dispersion used in the invention are described in detail in the U.S. Patents. Nos. 5,006,590 and 4,929,655, assigned to Kyoritsu Yuki Co. , Ltd., Tokyo, Japan, and the patents of E.U.A. Nos. 5,708,071 and 5,587,415 assigned to Hymo Corporation of Tokyo, Japan. The descriptions of these two patents are hereby incorporated by reference. This invention represents a substantial improvement in the technique of treating aqueous systems with dispersion polymers. As will be shown in the examples, the dispersion polymers of lower concentration used and currently described are lower than the dispersion polymers at higher concentrations described herein. The superiority of the polymers described herein is much greater than an additive effect in increments that would ordinarily be expected by those skilled in the art. The examples will illustrate this unexpectedly larger activity at a much lower dose, which was previously unpredictable.

The monomers According to the invention, the polymer dispersion used to treat the water produced is prepared from a water-soluble monomer mixture containing at least 5 mol% of a cationic monomer represented by the general formula (I): wherein Ri is H or CH3; R2 and R3 are each an alkyl group having 1 to 2 carbon atoms; i is an oxygen atom or NH; Bi is an alkyl group having 2 to 4 carbon atoms or a hydroxypropyl group and Xi 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 solution of the anionic salt. The polymer of the monomer mixture can also be used as the starting polymer. The starting polymer is described in detail below. The above cationic monomer represented by the general formula (I) is preferably a quaternary ammonium salt obtained by the reaction of benzyl chloride and dimethylaminoethyl acrylate, diethylaminoethyl acrylate, dimethylaminohydroxypropyl acrylate, dimethylaminopropyl acrylamide, dimethylaminoethyl methacrylate, methacrylate dimethylaminoethyl, diethylaminoethyl methacrylate and dimethylaminopropyl methacrylamide. The monomers copolymerized preferably with the cationic monomer represented by the general formula (I) include acrylamide, methacrylamide or other N-substituted (meth) acrylamides, and the cationic monomers represented by the general formula (II): wherein R is H or CH3; R5 and Re 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. Xi and X2 can be anionic counterions such as halides, pseudohalogenides, -SO3OCH3 and -OC (0) CH3 among others. Preferred monomers represented by the formula (II) include the ammonium salts of dimethylaminoethyl acrylate, diethylaminoethyl acrylate, dimethyl acrylate, inopropyl, diethylaminopropyl acrylamide and dimethylhydroxypropyl acrylate, dimethylaminoethyl methacrylate., diethylaminoethyl methacrylate, dimethylaminopropyl-methacrylamide, diethylaminopropylmethacrylamide and dimethylhydroxypropyl methacrylate or other N-substituted (meth) acrylamides, as well as the methylated and ethylated quaternary salts. Among the cationic monomers represented by the general formula (II) which are most preferred are the methylated quaternary salts and salts of dialkylaminoethyl acrylate and dialkylaminoethylmethacrylate. The concentration of the monomers mentioned above in the polymerization reaction mixture is suitably in the range of 5 to 30% by weight.

Anionic salts The anionic salt that will be incorporated into the aqueous solution according to the present invention is suitably a sulfate, a phosphate, a chloride or a mixture thereof. Preferred salts include ammonium sulfate, sodium sulfate, magnesium sulfate, aluminum sulfate, ammonium chloride, sodium chloride, ammonium acid phosphate, sodium acid phosphate and potassium hydrogen phosphate. In the present invention, these salts may each be used as an aqueous solution thereof having a combined concentration of 10% or more.

The dispersants A dispersing polymer (also referred to as a stabilizing 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 cationic polymer of high molecular weight. The dispersant polymer is at least partially soluble in the aqueous salt solution mentioned above. The dispersant polymer is preferably used in an amount of 1 to 10% by weight based on the total weight of the monomers. The dispersant polymer is composed of 5 mol% or more of a diallyldialkyl ammonium halide or of a cationic monomer unit represented by the formula I or II. Preferably, the residual molar percentage is acrylamide or methacrylamide or other N-substituted (meth) acrylamides or diallyldialkyl ammonium chloride. The dispersant performance 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 co-existent in the polymerization system. The deposition of the fine particles is carried out gently in the presence of these agents.

Polymers in dispersion For the polymerizations, a normal water-soluble radical forming agent may be employed, but preferably water-soluble azo compounds such as 2,2'-azobis (2-amidinopropane) hydrochloride and 2,2'-azobis hydrochloride are used. (N, N '-dimethylenisobutylamine). According to one embodiment of the invention, a starting polymer can be added prior to the start of the polymerization of the above monomers for the purpose of oning a fine dispersion. The starting polymer is a water-soluble cationic polymer insoluble in the aqueous solution of the anionic salt. The starting polymer is preferably a polymer prepared from the above monomer mixture by the process described herein. However, the monomeric composition of the starting polymer does not always have to be the same as that of the water-soluble cationic polymer formed during the polymerization. However, like the water-soluble polymer formed during the polymerization, the starting polymer must contain at least 5 mole percent of cationic monomer units represented by the general formula (I). According to one embodiment of the invention, the starting polymer used in a polymerization reaction is the water-soluble polymer prepared in a previous reaction that has used the same monomer mixture. One aspect of this invention is a method for clarifying wastewater with an effective clarifying amount of at least one dispersion of a water-soluble cationic polymer flocculant; wherein the water-soluble flocculant is added to the wastewater in an amount effective to flocculate suspended solids, the suspended solids are removed and clarified waters are oned, the dispersion of the water-soluble cationic polymer flocculant formed from polymerizing vinyl monomers under conditions of formation of free radicals in a medium containing water, monomers, stabilizing polymer and an aqueous solution of anionic salt; wherein the water-soluble cationic polymer flocculant is polymerized from: a) at least 5 mol% of a cationic monomer selected from the group consisting of: monomers of the general formula (I) wherein Ri is selected from the group consisting of H and CH3; R2 and R3 are selected from the group consisting of Ci alkyl and C2 alkyl; i is selected from the group consisting of 0 and NH; Bi is selected from the group consisting of C2 alkyl, C3 alkyl and hydroxypropoxy groups, and X is an anionic counterion, and monomers of the general formula II: II wherein R4 is selected from the group consisting of H and CH3; Rs and Re are selected from the group consisting of Ci alkyl and C2 alkyl; R7 is selected from the group consisting of a hydrogen atom, Ci 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 counter ion with b) at least 5 mol% of a monomer selected from the group consisting of N-alkyl acrylamide. C1-C10, N, N-dialkylarylamide of C1-C10, N-alkylmethacrylamide of C1-C10, N, N-dialkylmethacrylamide of C1-C10, N-arylacrylamide, N, N-diarylacrylamide, N-arylmethacrylamide, N, N- diarylmethacrylamide, N-arylalkyl acrylamide, N, N-diarylalkylacrylate ida, N-arylalkyl methacrylamide, N, N-diarylalkyl methacrylamide, acrylamide and methacrylamide; and wherein the stabilizing polymer is a cationic polymer that is at least partially soluble in the aqueous solution of the anionic salt, wherein the improvement comprises the addition of the water-soluble cationic flocculating polymer dispersion to the wastewater at a concentration of at least twenty-five percent by weight of polymer dispersion in water.

Another aspect of this invention is a method for dewatering wastewater with an effective dehydrating amount of at least one dispersion of a water-soluble cationic polymer flocculant; wherein the water-soluble flocculant is added to the wastewater in an amount effective to dehydrate suspended solids, the suspended solids are removed and clarified waters are obtained, the dispersion of the water-soluble cationic polymer flocculant formed from polymerizing vinyl monomers under conditions of formation of free radicals in a medium containing water, monomers, stabilizing polymer and an aqueous solution of anionic salt; wherein the water-soluble cationic polymer flocculant is polymerized from: a) at least 5 mol% of a cationic monomer selected from the group consisting of: monomers of the general formula I wherein Ri is selected from the group consisting of H and CH3; R2 and R3 are selected from the group consisting of Ci alkyl and C2 alkyl; i is selected from the group consisting of O and NH; Bi is selected from the group consisting of C2 alkyl, C3 alkyl and hydroxypropoxy groups, and X is an anionic counterion, and monomers of the general formula II: II wherein R is selected from the group consisting of H and CH3; Rs and R6 are selected from the group consisting of Ci alkyl and C2 alkyl; R7 is selected from the group consisting of a hydrogen atom, Ci 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 C alkyl and hydroxypropyl and X2 is an anionic counter ion with b) at least 5 mol% of a monomer selected from the group consisting of N-alkyl acrylamide C1 -C10, N, N-dialkylarylamide of C1-C10, N-alkylmethacrylamide of Ci-Cio, N, N-dialkylmethacrylamide of C1-C10, N-arylacrylamide, N, N-diarylacrylamide, N-arylmethacrylamide, N, N-diarylmethacrylamide , N-arylalkyl acrylamide, N, N-diarylalkylacrylamide, N-arylalkyl methacrylamide, N, N-diarylalkyl methacrylamide, acrylamide and methacrylamide; and wherein the stabilizing polymer is a cationic polymer that is at least partially soluble in the aqueous solution of the anionic salt; wherein the improvement comprises the addition of the water-soluble cationic flocculating polymer dispersion to the waste water at a concentration of at least twenty-five percent by weight polymer dispersion in water.

Yet another aspect of this invention is a method for improving the retention and drainage of processing waters in the production of pulp and paper with an effective amount of at least one dispersion of a water-soluble cationic polymer flocculant; wherein the water-soluble flocculant is added to the processing waters in an amount effective to improve retention and drainage, the dispersion of the water-soluble cationic polymer flocculant formed from polymerizing vinyl monomers under conditions of free radical formation in a medium containing water, monomers, stabilizing polymer and an aqueous solution of anionic salt; wherein the water-soluble cationic polymer flocculant is polymerized from: a) at least 5 mol% of a cationic monomer selected from the group consisting of: monomers of the general formula I wherein Ri is selected from the group consisting of H and CH3; R2 and R3 are selected from the group consisting of Ci alkyl and C2 alkyl; i is selected from the group consisting of 0 and NH; Bx is selected from the group consisting of C2 alkyl, C3 alkyl and hydroxypropoxy groups, and X is an anionic counterion, and monomers of the general formula II: II wherein R4 is selected from the group consisting of H and CH3; Rs and Re are selected from the group consisting of Ci alkyl and C2 alkyl; R7 is selected from the group consisting of a hydrogen atom, Ci 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 counter ion with b) at least 5 mol% of a monomer selected from the group consisting of N-alkyl acrylamide. C1-C10, N, N-dialkylarylamide of C1-C10, N-alkylmethacrylamide of C1-C10, N, N-dialkylmethacrylamide of C1-C10, N-arylacrylamide, N, N-diarylacrylamide, N-arylmethacrylamide, N, N- diaryl methacrylamide, N-arylalkyl acrylamide, N, N-diarylalkylacrylamide, N-arylalkyl methacrylamide, N, N-diarylalkyl methacrylamide, acrylamide and methacrylamide; and wherein the stabilizing polymer is a cationic polymer that is at least partially soluble in the aqueous solution of the anionic salt, wherein the improvement comprises the addition of the water-soluble cationic flocculating polymer dispersion to the wastewater at a concentration of at least twenty-five percent by weight of polymer dispersion in water.

Preferred polymeric flocculants are poly (DMAEA.MCQ / AcA), poly (DMAEA.BCQ / AcAm) and poly (DMAEA.MCQ / DMAEA.BCQ / AcAm). For any aspect of this invention, a stabilizing polymer can be polymerized from 5 mole% of cationic monomers selected from the group consisting of: monomers of the general formula I wherein Ri is selected from the group consisting of H and CH3, R2 and R3 are selected from the group consisting of Ci alkyl and C2 alkyl, Ai is selected from the group consisting of 0 and NH, Bi is selected from the group consists of C2alkyl, C3alkyl and hydroxypropoxy groups and Xi "is an anionic counterion, diallyldialkylammonium halides and monomers of the general formula II: II wherein R4 is selected from the group consisting of H and CH3; R5 and R6 are selected from the group consisting of Ci alkyl and C2 alkyl: R7 is selected from the group consisting of a hydrogen atom, Ci 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.A preferred diallyldialklammonium halide is diallyldimethylammonium chloride (DADMAC) .The wastewater may be selected from the gr upo that consists of industrial wastewater and municipal wastewater. In addition, industrial wastewater can be selected from the group consisting of wastewater from food processing, oily wastewater, wastewater from paper mills and wastewater contaminated with inorganic materials.

The polymers described herein can 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 with polymers that were manufactured by Derypol S.A. Corporation of Spain. Polymer preparations are available from Derypol S.A. Corporation with the trade name designations DR-2570 (sold at a concentration of 15%), DR-3000 and DR-4000 (both of which are sold at concentrations of 20%). The following examples are presented to describe preferred embodiments and utilities of the invention, and are not intended to limit the invention unless otherwise indicated in the appended claims.

EXAMPLE 1 A dispersion of 25% polymer solids, 65/25/10 molar percent of AcAm / DMAEA. BCQ / DMAEA. MCQ was synthesized as follows. A 1,500 cc reaction flask was equipped with a mechanical stirrer, thermocouple, condenser, nitrogen purge tube, addition port and heater tape. To this reaction was added 173.7 g of acrylamide (50% aqueous solution, available from Nalco Chemical Co. of Naperville, IL), 158.5 g of quaternary salt of dimethylaminoethyl acrylate benzylic chloride (80% aqueous solution, available from Nalco Chemical Co. of Naperville, IL), 45.5 g of quaternary salt of dimethylaminoethyl acrylate methyl chloride (80% aqueous solution, available from CPS Chemical Company of Old Bridge, NY), 18.8 g of glycerin, 45.9% of the homopolymer of methyl chloride of dimethylaminoethyl quaternary acrylate (20% aqueous solution, available from Nalco Chemical Co. of Naperville, IL), 16.7g of a copolymer of diallyldimethylammonium chloride and dimethyl aminoethyl quaternary acrylate benzylic chloride (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 diethylenetriamine pentaacetate (DABERSEEN 503, available from Derypol, SA 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 nitrogen purge, 3.7 g of a 1.0% aqueous solution of 2,2'-azobis (N, N '-dimethylenisobutyramidine) dihydrochloride (WAKO VA-044 available from Wako Chemicals 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 room temperature and 45.Og of ammonium sulfate, 10.Og of sodium thiosulfate and 10.Og of acetic acid were added. The final product was a milky and uniform white dispersion with a general viscosity of 1950 cps. After dilution to 0.5% active polymer, a solution viscosity of 74 cps in 2% aqueous ammonium sulfate was obtained.

EXAMPLE 2 To determine the increased effectiveness of the polymer with a higher polymer solids concentration synthesized according to the procedure of Example 1 to improve the clarity of the wastewater, tests were carried out on bottles in an animal feed production facility. . Small samples of 200 ml of untreated effluents were taken from a sump in the facility before the receiving 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 means of a visual evaluation with assigned values from 1 to 10, where 10 is the most free of solids and the most desirable. The flock size is also based on a visual evaluation, in which a larger floret (higher number) is more desirable. Table I illustrates the results of the comparison between Polymer A (polymer dispersion with 20% active DR-3000, available from Derypol, SA Corporation of Spain) and Polymer B (polymer dispersion with 25% active synthesized according to with the procedure described in Example 1). The molecular weights of the two polymers were considered equal based on the fact that Polymer A and Polymer B had equivalent reduced specific viscosity measurement values recorded in solutions of NaN03 at 0.125N. The doses of the products in Table 1 were adjusted to an equal polymer asset base. Normally one could expect an equal performance in an asset base since the polymers have the same chemical composition and molecular weight, but in this case an increased effectiveness and efficiency were evident with Polymer B of this invention, over that obtained with the Polymer A commercially available. An upper floccule size and water clarity were obtained with Polymer B compared to Polymer A, and thus a significantly lower treatment dose can be used. The surprising results were obtained at concentration values of 25%. A person skilled in the art, familiar with this surprisingly large result would then understand consequently that even higher concentrations should also produce this increased effect.

TABLE I Polymer A = dispersion polymer with 20% active DR-3000, available from Derypol, S.A. Corporation of Spain. Polymer B = polymer in dispersion with 25% active, synthesized according to the procedure described in Example 1. 1 = dose of polymer listed in an equal active base. 2 = scale of 1-10, with 10 more desirable since it represents the largest flock size. 3 = scale of 1-10, with 10 more desirable since it represents the highest clarity.

EXAMPLE 3 A comparison of the polymers synthesized according to the procedure of Example 1 was also done to verify the effectiveness as a treatment for the purposes of sludge dewatering in a twin belt press of a food production facility. Polymer A and Polymer B were fed to the food processing wastewater stream using a NALMAT dosing system (available from Nalco Chemical, Co., Naperville, IL.) Which was previously used for testing latex polymers. An initial dilution was carried out and the polymer was prepared as a diluted solution. The Polymer B solution had to be prepared at a lower concentration than that of Polymer A due to the much higher Brookfield viscosity. A primary dilute 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 concentrations are indicated in the results of Table II. The turbidity of the filtrate that was released from the band filter press was measured with a Hach® DR-2000 spectrophotometer. The lower the turbidity reading, the better the polymer performance. The solids in the cake (final mud at the outlet of the belt filter press) were determined gravimetrically according to standard procedures. The higher the solids in the cake, the more effective was the treatment in the dehydration of the wastewater with solids removed (or mud). The solids in the cake can be artificially high when the yield of the polymer is poor and a significant amount of solids is squeezed out of the machine. Therefore, the overall performance of the polymer should be considered. Since the performance of a web press is largely based on visual evaluation, the following parameters were observed: size and shape of the flocculent; clarity of the free drainage zone; stability of the mud in the zone of gradual variation of the thickness in the width (squeezed); and stability in the pressing zone (which includes stickiness of the cake and characteristics of the mat). These results are shown in Table II. An improved yield was obtained with Polymer B, on Polymer A commercially available. As a result of the treatment with Polymer B, the solids in the cake were similar to those in Polymer A. However, with Polymer B the overall quality was very good, the band was free from clogging (ie, clogged web) and the clarity of the filtered material was greater than a lower dose when compared to Polymer A. As in Example 2, an equal yield on an active basis could normally be expected, since the polymers have the same chemical composition and molecular weight. However, increased effectiveness and efficiency with Polymer B of this invention were evident over those obtained with commercially available Polymer A.

TABLE II N / D = not available Polymer A = dispersion polymer with 20% active DR-3000, available from Derypol, S.A. Corporation of Spain. Polymer B = polymer in dispersion with 25% active, synthesized according to the procedure described in Example 1. 1 = dose of polymer listed in an equal active base. 2 = listed as concentration in active polymer solution. The first number represents the primary dilution, the second number represents the secondary dilution. 3 = higher percentages of solids in the cake are more desirable. 4 = lower turbidity is more desirable.

EXAMPLE 4 The polymers synthesized according to the procedure of Example 1 were also compared in terms of their capabilities to dehydrate sludge during centrifugation from oily and grease-containing wastewater in a wastewater disposal facility. Polymer A and Polymer B were fed in line using a Gear rope. With this type of installation, a change in the dose would automatically lead to a change in the concentration of the solution as shown in Table III. The clarity and quality of centering cake (leaving water coming from the centrifuge) 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 centering clarity, the better the polymer performance. Even though the clarity of the centering was equal between the two polymers at equal doses, Polymer B was superior due to the higher cake quality (cake drier, less sticky, more compact) through the dosage scale . In this Example, as with the previous examples, one would normally expect an equal performance in an asset base since the polymers have the same chemical composition and molecular weight. Table III indicates that increased effectiveness and efficiency were evident with Polymer B of this invention, over that obtained with Commercially available Polymer A.

TABLE III Polymer A = dispersion polymer with 20% active DR-3000, available from Derypol, S.A. Corporation of Spain. Polymer B = polymer in dispersion with 25% active, synthesized according to the procedure described in Example 1. 1 = dose of polymer listed in an equal active base. 2 = listed as concentration in active polymer solution. 3 = scale of 0-3, 0 represents the highest water clarity and is the most desirable.

EXAMPLE 5 The polymers synthesized according to the procedure of Example 1 were also compared in terms of their capabilities to dehydrate sludge composed of contaminated inorganic soils of railways. A procedure similar to that of Example 2 was used to obtain the results of Table IV. The dose of the polymers in Table IV were adjusted to an equal polymer asset base. The performance of the polymers was evaluated in terms of flock size (the largest flock size is more desirable), sedimentation rate of the mud (a faster sedimentation rate is more desirable), stability of the flock to the shear stress ( stronger resistance to shear stress is more desirable) and drainage velocity (higher volume of drained water is more desirable). Although an equal return on an asset base would normally be expected since the polymers have the same chemical composition and molecular weight, Table IV shows that increased effectiveness and efficiency were evident with Polymer B over those obtained with commercially available Polymer A .

TABLE IV Polymer A = dispersion polymer with 20% active DR-3000, available from Derypol, S.A. Corporation of Spain. Polymer B = polymer in dispersion with 25% active, synthesized according to the procedure described in Example 1. 1 = dose of polymer listed in an equal active base. 2 = listed as concentration in active polymer solution. 3 = larger flock is more desirable. 4 = faster sedimentation is more desirable. 5 = stability of the larger flock is more desirable. 6 = faster drainage is more desirable.

EXAMPLE 6 The polymers synthesized according to the procedure of Example 1 were also compared in terms of their retention and drainage capabilities, in a recycled cardboard mill Both Polymer A and Polymer B were fed directly in line before the first analysis.

A simple static mixer was used to prepare the polymer solution. No aging tank was required. The yield of the two polymers was evaluated by measuring the First Pass Retention (FPR). The FPR is a measure of the amount of fibers, fine particles and fillers that are retained in the paper sheet and is calculated by means of the following equation:% FPR = [(AB) / A] x 100 A = concentration of the head box paste (g / 1) B = white water concentration (ie, filtered material) (g / 1) It is desirable to have a% FPR as high as possible. As clearly shown in Table V, Polymer B was more efficient than Polymer A, since a significantly lower dose of Polymer B was required in order to achieve a% FPR equal to that obtained with the use of Polymer A. again, an equal yield on an asset base would normally be expected since the polymers have the same chemical composition and molecular weight, but in this case an increased efficiency was evident with Polymer B of this invention, above that obtained with the Polymer A commercially available.

TABLE V Polymer A = dispersion polymer with 20% active DR-3000, available from Derypol, S.A. Corporation of Spain. Polymer B = dispersion polymer with 25% active, synthesized according to the procedure described in Example 1. 1 = higher percentages of first pass retention are desired. 2 = dose of polymer listed on an equal asset base.

EXAMPLE 7 The polymers synthesized according to the methods of Example 1 were also compared in their ability to dehydrate oily sludge from a refinery. A mud sample was taken before the twin band press used for dehydration. The polymers were evaluated using a free drainage test carried out in the following manner: The desired amount of polymer was added to 200 L of mud and mixed with inversions using graduated cylinders. The test load was poured into a tube that rested on a filter cloth and the timing was started immediately. The free drainage volume obtained after 10 seconds was recorded. The results are shown in Table IV, where the drainage volume is given at 10 seconds. The higher the volume drained, the more effective dehydration is. As clearly shown in Table IV, Polymer B outperformed Polymer A in an asset base, since Polymer B is both more effective (higher drained volume) and more efficient (less required dose). Again, an equal yield on an asset base would normally be expected since the polymers have the same chemical composition and molecular weight, but in this case an increased efficiency was evident with Polymer B of this invention, above that obtained with the Polymer A commercially available.

TABLE VI Polymer A = dispersion polymer with 20% active DR-3000, available from Derypol, S.A. Corporation of Spain. Polymer B = polymer in dispersion with 25% active, synthesized according to the procedure described in Example 1. 1 = dose of polymer listed in an equal active base. 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. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (7)

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. A method for treating water with an effective clarifying amount of at least one dispersion of a water-soluble cationic polymer flocculant; wherein the water-soluble flocculant is added to the water in an amount effective to flocculate suspended solids, the suspended solids are removed and a clarified water is obtained, the dispersion of the water-soluble cationic polymer flocculant formed from polymerizing low vinylic monomers conditions for formation of free radicals in a medium containing water, monomers, stabilizing polymer and an aqueous solution of anionic salt; characterized in that the water-soluble cationic polymer flocculant is polymerized from: a) at least 5 mol% of a cationic monomer selected from the group consisting of: monomers of the general formula (I) wherein Ri is selected from the group consisting of H and CH3; R2 and R3 are selected from the group consisting of Ci alkyl and C2 alkyl; i is selected from the group consisting of 0 and NH; Bi is selected from the group consisting of C2 alkyl, C3 alkyl and hydroxypropoxy groups and X is an anionic counterion, and monomers of the general formula II: II wherein R is selected from the group consisting of H and CH; Rs and Re are selected from the group consisting of Ci alkyl and C2 alkyl; R7 is selected from the group consisting of a hydrogen atom, Ci 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, C alkyl and hydroxypropyl and X2 ~ is an anionic counter ion with b) at least 5 mol% of a monomer selected from the group consisting of N-alkyl acrylamide C1-C10, N, N-dialkylarylamide of C1-C10, N-alkylmethacrylamide of C1-C10, N, N-dialkylmethacrylamide of C1-C10, N-arylacrylamide, N, N-diarylacrylamide, N-arylmethacrylamide, N, N- diaryl methacrylamide, N-arylalkyl acrylamide, N, N-diarylalkylacrylamide, N-arylalkyl methacrylamide, N, N-diarylalkyl methacrylamide, acrylamide and methacrylamide; and wherein the stabilizing polymer is a cationic polymer that is at least partially soluble in the aqueous solution of the anionic salt, wherein the addition of the water-soluble cationic flocculating polymer dispersion is carried out to the waste water at a concentration of at least twenty-five percent by weight of polymer dispersion in water.

2. The method in accordance with the claim 1, characterized in that the anionic salt is selected from the group consisting of phosphates, sulfates, chlorides and mixtures thereof.

3. The method in accordance with the claim 2, characterized in that the stabilizing polymer is polymerized from at least 5 mol% of cationic monomers selected from the group consisting of: monomers of the general formula I wherein Ri is selected from the group consisting of H and CH3, R2 and R3 are selected from the group consisting of Ci alkyl and C2 alkyl, i is selected from the group consisting of 0 and NH, Bi is selected from the group consisting of C2 alkyl, C3 alkyl and hydroxypropoxy groups and X ? ~ is an anionic counterion, diallyldialkyl ammonium halides, monomers of the general formula II: II wherein R 4 is selected from the group consisting of H and CH 3, Rs and Re are selected from the group consisting of Ci alkyl and C 2 alkyl, R 7 is selected from the group consisting of a hydrogen atom, Ci 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, C alkyl and hydroxypropyl and X2 ~ is an anionic counterion, and combinations thereof.

4. The method in accordance with the claim 3, characterized in that the additional step of adding an effective amount of at least one coagulant to the waste water.

5. The method in accordance with the claim 4, characterized in that the water is selected from the group consisting of industrial wastewater and municipal wastewater.

6. The method in accordance with the claim 5, characterized in that the industrial waste water is selected from the group consisting of food processing waste water, oily waste water, waste water from paper mill and waste water contaminated with inorganic materials.

7. The method in accordance with the claim 6, characterized in that the water to be treated is selected from the group consisting of clarifying wastewater, the dehydration of wastewater and the improvement of retention and drainage of processing water in the production of pulp and paper.