MXPA97002741A - Methods of coagulation and decoloration decorrientes residua - Google Patents

Abstract

The present invention relates to a method for separating suspended solids from a waste stream or natural water, characterized in that it comprises: i) adding to the waste stream in an amount sufficient to coagulate the solids, a composition comprising polyamine and colloidal acid polymer of melamine aldehyde, in a ratio of about 90.0-99.9 parts by weight of polyamine to about 10.0-0.1 parts by weight of the colloidal acid polymer, wherein the polyamine is a reaction product of a secondary amine and a difunctional epoxy compound or a precursor thereof and ii) separate the solids from the waste stream or natural water.

Description

METHODS OF COAGULATION AND DISPOSAL OF WASTE CURRENTS FIELD OF THE INVENTION This invention relates generally to the clarification of wastewater or natural waters, more specifically, to the coagulation and discoloration of process waters resulting from deinking, pulp and paper mills using melamine-aldehyde polymer combined with ina polia i BACKGROUND OF THE INVENTION To recycle used paper, paper typically goes through a de-inking process, which initially removes the fiber from the paper, for example, waste newspaper paper, in a water bath containing a deinking agent and a detergent or other active surface agent besides paper. As the fiber is removed from the newspaper, the ink is removed from the fibers. Various combinations of washing, flotation and cleaning steps are used to separate the fibers from one another and from the ink and to remove the ink and other materials from the pulp again whipped. The REF: 24275 effluent streams resulting from this process, also called process waters, contains colored bodies which generally include inks - both water-based inks such as flexographic inks and oil-based inks, such as inks without impact and lithographic inks - as well as lignins, degradation products of lignin, humic acids and pectins. The bodies of color can be found in other types of waste streams and natural waters, such as bodies of fresh water. In the waters of the process of clarification by de-inking, or other wastewater containing colored bodies, it is important to eliminate the solids suspended in them, as well as to discolor the water. Many existing coagulants, however, are not very effective in bleaching and many bleaching agents are less effective at coagulating suspended solids. Since newspaper paper continues to contain larger amounts of water-soluble inks, such as flexographic ink, the clarification of process waters containing colored bodies has become more difficult. Accordingly, there is a need, particularly in the paper recycling industry, for a material that can effectively coagulate suspended solids, as well as to remove colored bodies from waste water, particularly, colored bodies comprising ink flexographic Among the various agents used in the art to clarify waters from the deinking process and other wastewater charged with ink, it has been taught in the art that polyamines and acid colloidal polymers of melamine formaldehyde are effective. Macroporous aminotriazinaldehyde resins have been described as useful for the treatment of effluents from paper pulp mills. In US Pat. No. 5,286,390, it is taught that an acid colloidal polymer of melamine formaldehyde is useful for separating charged solids from ink and turbidity from the waters of the deinking process. Optionally, an effective amount of the flocculant may be added subsequently to assist in the separation of the solids / liquid. However, it has been found that such acid colloidal polymers are relatively poor coagulants. • Polyamines have been used as coagulants, often together with a flocculant, in the treatment of wastewater. For example, the copolymers of diallyldimethylammonium chloride and the anionic monomer are described in U.S. Patent 5,013,456 and U.S. Patent 5,207,924 as being useful for coagulating suspended solids from the waters of the deinking process. In U.S. Patent 5,209,854, copolymers of diallyldimethylammonium chloride and certain anionic comonomers are taught as useful for decolorizing wastewater from pulp mills. See also American patents 4, 746,457 and 5,330,656. Polyamines made of epoxy compounds and secondary amines are also taught to be useful for clarifying natural water in US Patent 3,894,944 and in US Patent 3,894,945 and to flocculate industrial waste in US Patent 3,894,947, each of which is incorporate as a reference. These polyamines, however, tend to exhibit insufficient efficacy for color removal at normal doses. The polyamines have been used in conjunction with other clarification aids to treat certain wastewater. Water-soluble polyamine epichlorohydrin polymers, among other cationic polymers, are taught in WO 93/02967, as useful in combination with an anionic colloidal material for flocculating suspended solids in waste water loaded with ink. EP 529 865 discloses methods for decolorizing effluent streams from pulp mill plants using ferrous sulfate and any water-soluble cationic polyamines, such as diallyldimethylammonium chloride polymers or polyamines made from epihalohydrin and lower alkyl diamines. The polyamines made of epichlorohydrin have also been used together with an acid coloration polymer of melamine formaldehyde to treat waste streams resulting from paper production and municipal sludge treatment. In such cases, the polyamine and the acid colloidal polymer were fed separately into the residual effluent stream in a ratio of 1: 1 or 2: 1, at the site. But this resulted in less than satisfactory clarification of the water. It has now been found that premixing a small amount of acid colloidal polymer from melamine formaldehyde to polyamine made from an epoxy compound and a secondary amine improves the performance of the polyamine with respect to coagulation, in the removal of solids and turbidity, as well as discoloration. The resulting composition remains stable for extended periods of time and can be used to clarify any residual streams or natural waters containing suspended solids and preferably to coagulate, more preferably to coagulate and discolor waste streams containing colored bodies. Given the chemistry of the polyamine and the sensitivity of the acid colloidal polymer of melamine formaldehyde to the pH concentrations beyond the pH range of about 1.4 to 2.2, it was surprising to find that the colloidal polymer of melamine formaldehyde acid could actually be combined with the polyamine to form a stable composition that has improved coagulant performance, without destroying the effectiveness of melamine formaldehyde. The use of a mixture of an acid colloidal polymer of melamine formaldehyde and a polyamine, provides better coagulation to facilitate the separation of suspended solids and colored bodies from the treated water than the use of the polymer alone at the same dose. Since acid melamine aldehyde colloidal polymers are less expensive than polyamines, the improved coagulating compositions of the present invention are also economically convenient1. In addition, advantages in handling and processing are obtained by the ability to use only one feed line for the polyamine / colloidal acid melamine formaldehyde polymer mixture, instead of two separate feed lines for the two polymer components.

BRIEF DESCRIPTION OF THE INVENTION The present invention provides a composition for separating, preferably by coagulation, suspended solids and color bodies in effluents or waste water streams, preferably those resulting from deinking, or paper or pulp milling operations.

Natural waters containing suspended solids and / or colored bodies can also be treated by the compositions herein. The term "coagulant" as used for the purposes of this invention, refers primarily to agents that cause the agglomeration or precipitation of solids, for example, charge neutralization (technically known as coagulation) and may also include agents that combine ios solids in larger agglomerations or "flocs", for example, through the formation of bridges (technically known as flocculation). In accordance with this invention, compositions comprising a polyamine and a melamine acid colloidal polymer are provided in a ratio of about 90.0-99.9 parts by weight of polyamine to about 10.0-0.1 parts by weight of acid colloidal polymer, wherein the polyamine is a reaction product of a secondary amine and a difunctional epoxy compound or a precursor thereof. The compositions of the present invention, comprising polyamine and a melamine aldehyde polymer in the amounts specified herein, are also called "coagulant compositions", for the purposes of this invention. Preferably, the compositions of the present invention consist essentially of an acid colloidal polymer of melamine formaldehyde and a polyamine. The present invention also provides a method for separating suspended solids from a waste stream or natural water comprising: (i) adding to the waste stream, in an amount sufficient to coagulate the solids, a composition comprising a polyamine and an acid colloidal polymer of melamine aldehyde, in a ratio of about 90.0-99.9 parts by weight of the polyamine and about 10.0-0.1 parts by weight of an acid colloidal polymer; wherein the polyamine is a reaction product of a secondary amine and an epoxid compound. difunctional or a precursor thereof; and (ii) separate the solids from the waste stream or natural water. Preferably, the ratio of polyamine to acid colloidal polymer ranges from about 96.5 to about 99.9 parts by weight of the polyamine to about 3.5-0.1 parts by weight of acid colloidal polymer. In another embodiment of this invention, a method is provided for separating suspended solids and color bodies from water from the deinking process, which results from the paper recycling process, which comprises: (i) adding to the process water of about .5 to about 150 parts per million, based on the process water, of a composition comprising polyamine and an acid colloidal polymer of melamine formaldehyde in a ratio of about 96.5-99.9 parts by weight of polyamine to about 3.5-1.1 parts by weight of an acid colloidal polymer; wherein the polyamine is a reaction product of a secondary amine: > and a difunctional epoxy compound or a precursor thereof; and (ii) separating the solids and the colored bodies from the process water.

DETAILED DESCRIPTION OF THE INVENTION The polyamines used in the present invention are those formed by the reaction of difunctional epoxy compounds with secondary amines of lower alkyls. These polyamines are well known in the art and are described in, for example, U.S. Patent 3,894,944; U.S. Patent 3,894,945; U.S. Patent 3,894,946; U.S. Patent 3,894,947; and U.S. Patent 3,894,947, the description of each of which is incorporated as Reference. The difunctional epoxy compounds used to make the polyamines are usually halohydrins, such as epihalohydrins and epihalohydrin precursors, which are converted to the corresponding epoxy compounds under alkaline conditions. The preferred epichlorohydrin. Typical secondary amines used to prepare the polyamines used in the present invention include those containing alkyl groups having from 1 to 3 carbon atoms; dimethylamines are preferred. The molecular weight of the polyamines used in the present invention is not critical. Usually, the molecular weight ranges from about 25,000 to about 1 million, preferably 50,000 to 250,000. Commercial polyamine products are typically diluted with water to form an aqueous polyamine solution. The concentration of polyamine in these solutions is not critical, although it preferably ranges from about 25 to about 50 weight percent polyamine. The pH of these polyamine solutions can vary anywhere from about 5 to about 7. Suitable acid melamine aldehyde colloidal polymers, also referred to herein as "melamine aldehyde polymers" or "acid colloidal polymers" (or MFAC), unless the context dictates otherwise, they include any polymer prepared from the following two components: 1) a melamine or substituted melamine, and 2) a compound having the following general formula wherein Ri and R2 are selected of the group consisting of H and linear or branched alkyl groups having 1-4 carbons and wherein Ri and R2 may be the same or different. As the first component, suitable substituted melamines are known in the art or can be obtained by someone skilled in the art through routine experimentation; Preferred substituted melamines include trimethylolmelamine, N-guanyl ** melamine, N-phenylmelamine, N-benzylmelamine and benzoguanaminfe, With respect to the second component, aldehydes such as formaldehyde, acetaldehyde and propionaldehyde, trioxane, paraformaldehyde and mixtures thereof and the like are preferred, with formaldehyde as the most preferred. The molar ratio of the first component (melamine) to the second The component preferably ranges from about 1: 1 to about 1: 6, more preferably from about 1: 2 to about 1: 4, still more preferably, from about 1: 3 to about 1: 4. The most preferred melamine formaldehyde polymer is prepared from about 1 mole of melamine or derivative thereof to about 3 to about 4 moles of formaldehyde. The melamine formaldehyde polymers used in the present invention are well known to those skilled in the art and are described in, for example, U.S. Patent No. 2,609,307, which is incorporated herein by reference. Since the melamine formaldehyde polymer tends to be insoluble in water, it usually exists in the form of an acid colloidal polymer, which means that the melamine formaldehyde polymer is kept in an acidic aqueous solution, generally a colloidal suspension, which contains typically any from about 0.1 to about 20 percent by weight of melamine aldehyde, preferably about? to about 15 weight percent and more preferably, about 4 to about 12 weight percent of melamine aldehyde; the acid is present in sufficient amounts to maintain a low pH, such that the melamine aldehyde polymer will remain as a colloidal suspension and will not precipitate. Preferably, the pH of the colloidal suspension of the melamine aldehyde polymer varies from about 1.4 to about 2.2, more preferably from about 1.6 to about 1.8. A wide range of acids can be used to prepare the acid colloid of melamine aldehyde, such as, for example, acetic, hydrochloric, phosphoric, formic, propionic; Hydrochloric acid is the most preferred.

Stabilizing agents known in the art such as alcohols, for example methanol, can also be included in the acid colloidal polymer. The molecular weight of the melamine aldehyde acid colloidal polymer is not critical. The preferred molecular weight ranges from about 500 to about 200,000, more preferably from about 75,000 to about 175,000. Suitable melamine aldehyde acid colloidal polymers (MFAC) are known in the art and are commercially available, for example, from Cytec Industries Inc., under the trademark PARAMEL®. In the preparation of the coagulant compositions of the present invention, it is preferable to add the MFAC to the polyamine and not the polyamine to the melamine polymer. aldehyde. The ratio of polyamine to MFAC is important and usually ranges from about 90.0-99.9 parts by weight of polyamine to about 10.0-0.1 parts by weight of MFAC, preferably from about 93.0-99.1 parts by weight of polyamine to about 7.0-0.1. parts by weight of MFAC, more preferably, from about 96.5-99.9 parts by weight of polyamine to about 3.5-0.1 parts by weight of MFAC and still more preferably, from about 98.0-99.9 parts by weight of polyamine to about 2.0-0.1 parts by weight of MFAC. A more preferred range also includes about 98.04-99.64 parts by weight of polyamine at about 1.96-0.36 parts by weight of MFAC. Thus, the amount of MFAC in the coagulating composition is usually at least 0.1 parts, preferably at least 0.2 parts, still more preferably at least 0.36 parts. The melamine aldehyde polymers are mixed in the polyamine or in the aqueous polyamine solution with gentle agitation, usually for 15-20 minutes. Additional materials may be added to the coagulant composition provided that the materials do not inhibit the coagulation performance of the composition. Such additional materials include, for example, alcohols, glycols and mixtures thereof and the like. The compositions of the present invention can be added to the water to be treated by any conventional method. Preferably, the coagulant composition is added to the waste stream or to the natural water to be treated in a water feed line. The addition of an effective amount of coagulant composition generally causes the formation of different flocs by means of coagulation. Any type of waste stream or natural water containing suspended solids can be treated by the compositions of the present invention, generally waste streams such as sludge, preferably any waste stream or natural water containing colored bodies and suspended solids. , preferably waste pulp and paper milling streams, still more preferably, waste streams resulting from the deinking processes. It is recognized in the art that the nature of suspended solids and colored bodies in waste streams and natural waters will vary depending on their point of origin, their path course, the mixing of other waters with them and the discharge of treated water in them. The final uses for waste streams and natural waters can also vary, for example, from recycling for industrial purposes, ie, paper and de-inking plants, for suitable uses for bathing and drinking. These variations in suspended solids content and usage often dictate different desired degrees of clarification. Accordingly, the desired dose of coagulant composition will vary depending on the particular waste stream or natural water to be treated, given the variables mentioned above. Consequently, the amount of coagulant composition to be used, should generally be a sufficient amount to coagulate the suspended solids in the waste stream or natural water to be treated, preferably, an amount sufficient to coagulate the suspended solids and the colored bodies therein, to facilitate the separation of the solids. the suspended solids and colored bodies of the treated water. This can be easily determined by someone skilled in the art by routine experimentation. Typically, the dose of coagulant composition may vary from about 0.5 to about 150 parts per million, based on the wastewater or treated natural water, preferably from about 7.5 to about 50 parts per million. To treat water from In the deinking process, the dose usually varies from about 5 to about 150 parts per million *, based on the treated process water, preferably from about 1 to about 100 parts per million. For the treatment of process waters resulting from the pulp and paper mills, the dosage usually varies from about 1 to about 20 parts per million, based on the treated process water. After the addition of the coagulating composition, the coagulated solids and the colored bodies are separated "") of the waste stream or natural water to be treated by any conventional means of solid / liquid separation, such as clarifiers, dissolved air flotation or sedimentation clarifiers. Optionally, a flocculant, that is, an agent that combines the solids in larger agglomerates or flocs, can be added in an amount sufficient to flocculate the agglomerated solids and therefore, further facilitates solid / liquid separation. The type of flocculant is not critical to the present invention, and suitable flocculants include conventional anionic, cationic, nonionic and amphoteric polymers, mixtures thereof and the like. It is preferable to use an anionic flocculant, especially in the treatment of water from the deinking process and wastewater from paper and pulp. Preferred anionic polymer flocculants, include those made from the following monomers: acrylic acid, methacrylic acid? Ethacrylate acid and its alkali metal or ammonium salts? vinyl sulfonic acid, 2-acrylamido-2-alkylsulfonic acids and 2-acrylamido-2-alkylsulfonates, wherein the alkyl group contains from 1 to 6 carbon atoms, such as acrylamido-2-methyl propanesulfonic acid or mixtures of any of the above and their alkali metal or ammonium salts. Hydrolyzed acrylamide can also be used. The anionic monomers can be copolymerized with (alk) acrylamide, preferably acrylamide or methacrylamide. Preferred cationic polymer flocculants include those prepared from the following monomers: dialkylaminoalkyl (meth) acrylates and dialkyl aminoalkyl (meth) acrylamides, including their acid addition salts or their quaternary ammonium salts, diallyl dialkyl ammonium halides, salts of vinyl benzyltrialkyl ammonium, and the like. The quaternized Mannich polymer or methylated dialkyl amino (ale) acrylamide polymers, such as the quaternary N-trimethylaminomethylacrylamide prepared by the functionalization of (ale) acrylamide or poly (ale) acrylamide may be particularly preferred for certain applications. Specific examples of preferred cationic monomers include, N-dimethylaminomethyl acrylamide, acryloxyethyltrimethylammonium chloride, methacryloxyethyltrimethylammonium chloride, 2-methacryloyl-oxyethyltrimethyl ammonium methosulfate, 2-methacryloyloxyethyltrimethyl ammonium chloride, diallydimethylammonium chloride, 3-acrylamido chloride. 3-methyl butyl trimethyl ammonium, 2-acrylamido-2-methylpropitrimethylammonium chloride, 3-methacryloyl-2-hydroxypropyltrimethylammonium chloride, dimethylaminoethyl acrylate, dimethylaminoethylmethacrylate or mixtures of any of the foregoing. Mixtures of any of the above cationic monomers together with (meth) acrylamide are also useful. Non-ionic polymer flocculants include those prepared from the following monomers: acrylamide; methacrylamide; dialkylaminoethyl acrylamides; N, N-dialkylacrylamides; N-alkyl acrylamides; N-vinyl acetamide; N-vinyl formamide; N-vinyl pyrrolidone and mixtures thereof. Acrylamide and methacrylamide are especially preferred. The flocculants of amphoteric polymers for use in the present invention comprise copolymers 5 of one or more of the above anionic monomers and one or more of the aforementioned ethylenically unsaturated cationic monomers or monomers, both of which contain anionic functionalities and cationic. Representative examples of polyanfoliths include polymers • or comprising i) acrylic acid, methacrylic acid, 2-acrylamido-2-methyl-propylsulfonic acid or 2-methacrylamido-2-t-methylpropylsulfonic acid, alone or in combination, and ii) dimethyldiallylammonium chloride, dimethyldiallylammonium bromide, chloride of diethyldiallylammonium and diethyldiallylammonium bromide, together or in combination, wherein the weight ratio of component i) to component ii) varies from about 90:10 to about 10:90. The polyanfolytes may also contain nonionic portions such as acrylamide or methacrylamide. The most preferred flocculants to be used with the compositions of the present invention are anionic polymers, preferably anionic polymers containing from about 2 to about 50 mole percent anionic functionality, more preferably 10 mole percent. to about 40 mole percent of anionic functionalities, based on the monomer. Such anionic polymers preferably have a molecular weight of at least 16 million, more preferably at least 30 million. The most preferred anionic flocculants, which can be used in the present invention, include hydrolyzed polyacrylamide, acrylamide / acrylic acid copolymers, acrylamide / acrylate copolymer, polyacrylates and acrylamide / acrylamido methylpropane sulphonic acid copolymers. The preferred amounts of polymeric flocculant may vary depending on the water to be treated and the dose of the coagulant composition. In this regard, the optimum dose of flocculant can be readily determined by one skilled in the art by routine experimentation. For process waters resulting from the deinking process, for example, doses of flocculants ranging from about 1 to about 125 ppm, based on the process water, may be preferred. After the addition of the polymeric flocculant to the waste stream or natural water, the suspended solids and color bodies can be removed by any conventional means known in the art, such as, for example, clarifiers, settling tank.

It is believed that one skilled in the art can use the foregoing description to utilize the present invention to its full extent.

DESCRIPTION OF THE PREFERRED MODALITIES EXAMPLE 1 The following examples are set forth for purposes of illustration only, and are not constructed as limitations of the present invention as set forth in the appended claims. Graduated cylinders were filled with 250ml of untreated process water, collected from an alkaline clarifier in a paper deinking plant for old newspaper / old magazines. The coagulant composition used was prepared by adding .5g of melamine formaldehyde acid colloid (MFAC) (9% by active weight, pH about 1.8) to 25g of polyamine (50% by active weight). The polyamine was made from epichlorohydrin and dimethylamine and had a molecular weight of about 75,000. The MFAC had a molecular weight of approximately 175,000. The coagulant composition comprises polyamine and MFAC in a ratio of 98.04 parts by weight of polyamine to 1.96 parts by weight of MFAC. To the process water an amount of coagulant composition was added to deliver a polymer with 50ppm (real), based on the process water. The cylinder was then inverted six times to ensure adequate mixing and to initiate coagulation. A hydrolyzed polyacrylamide flocculant (molecular weight of about 32 million) containing about 40 mole percent of anionic functionality, based on the monomer, was subsequently added at a dose of 3.8 ppm polymer, based on the process water, to facilitate liquid / solid separation. After the addition of the flocculant, the cylinder was inverted twice to initiate the flocculation process. Were the flocculus size evaluated? stability and speed of liquid / solid separations. A portion of the resulting filtrate was removed and the following parameters were measured: turbidity (NTU), color (L *, a *), as measured by the CIELAB color space system and the percentage of total suspended solids (TSS), removed. The results are presented in TABLE 1.

EXAMPLE 2 The procedure used in the Example 1, except that the coagulant composition was prepared by adding .09g of MFAC (9% active weight, pH about 1.8) to 25g of polyamine (50% active weight).

The ratio of polyamine to MFAC in the composition was 99.64 parts by weight of polyamine to 0.36 parts by weight of MFAC. The results for the filtrate turbidity, floc stability, color measurements and total suspended solids removed appear in TABLE 1.

EXAMPLE 3 The procedure used in Example 1 was used, except that the coagulant composition was prepared by adding 0.09g of MFAC (9% active weight, mp? Approximately 1.8) to lOg polyamine (50% active weight)? The ratio of polyamine to MFAC in the composition was 99. 14 parts by weight of polyamine to 0.89 parts by weight of MFAC. The results are listed in TABLE 1.

EXAMPLES 4-6 The tests in Examples 4-6 were performed as controls and do not represent the invention. For the Example 4, the procedure used in Example 1 was followed, except that no coagulant and no flocculant were added. In Example 5, the procedure used in Example 1 was used, except that 50 ppm of polyamine was added to the process water, based on the process water. Subsequently, 3.8ppm of the anionic flocculant used in Example 1 was also added with agitation. The results are listed in TABLE 1. In Example 6, the procedure used in Example 1 was used, except that 50 ppm was added. from MFAC to process water, based on process water. Subsequently, 3.8ppm of the anionic flocculant used in Example 1 was added. The results appear in TABLE 1. The results of Table 1, show that the addition of certain small amounts of MFAC to an epichlorohydrin polyamine, improves the elimination of the color and coagulation and the performance of polyamine, providing better filtration quality, floc stability and elimination of total suspended solids. The compositions comprising polyamine and MFAC in a general ratio of about 97.5 to about 99.9 parts of polyamine at about 2.5 to about 0.1 of MFAC, preferably 98.04 to about 99.64 parts of polyamine at about 1.96 to about 0.36 parts of MFAC, as shown in Table 1 above, provides superior performance with respect to coagulation and color removal, as compared to the use of a polyamine or an MFAC alone, at the same dose.

TABLE 1 color designations a * denotes red L * denotes Black / White, where 0 = Black 100 = White ** is not representative of the invention TABLE II EXAMPLE MFAC RELATIONSHIP: POLIAMI A IN TURBIDITY DOSE THE COAGULATING COMPOSITION OF 1 FILTERED NTU White 0 > 2000 1.96 parts of MFAC 50 301 98.04 parts of Polyamine 0.36 parts of MFAC 50 390 99.64 parts of Polyamine 10 0.89 parts of MFAC 50 360 99.11 parts of Polyamine 11 3.47 parts of MFAC 50 371 96.53 parts of Polyamine 12 '100 parts of MFAC 50 > 2000 ** not representative of the invention 'ppm, based on process water EXAMPLES 7-12 For Examples 7-12, the procedure in Example 1 was used to treat a process water from a paper deinking mill, using compositions containing polyamine (molecular weight of 50,000) and MFAC (active 9%, pH around of 1.8, molecular weight of about 175,000) in various ratios, as set forth in Table II, except that 3.9 ppm of a hydrolyzed polyacrylamide of 30 mol percent was used as a flocculant.

EXAMPLES 13-19 Compositions containing polyamine (molecular weight of about 75,000) and MFAC (molecular weight of about 175,000) were prepared in various proportions and their physical appearance was observed and set forth in Table III. The observations indicated that MFAC levels generally greater than 30 parts, preferably greater than 10 parts, decrease the stability and clarity of the coagulant compositions.

TABLE III Example Composition Weight ratio Physical Appearance of Polyamine to MFAC 13 Polyamine 100 mbar, transparent 14 MFAC 100 Clear, transparent Polyamine 95 Amber, transparent, MFAC 5 Light precipitate 16 Polyamine 90 Amber, translucent, MFAC 10 precipitate 17 Polyamine 70 White, opaque i MFAC 30 18 Polyamine 50 White, opaque MFAC 50 19 Polyamide 40 White, opaque MFAC 60 EXAMPLES 20-28 The procedure in Example 1 was used to treat process water from a paper deinking mill (70% paper for newspaper, old / 30% magazine, old) using compositions containing polyamine (molecular weight of approximately 75,000, 50 '- active) and MFAC (9 °, active) in various proportions as set out in Table IV. In this particular process water, the optimum ratio appears to be from about 1.96% MFAC to 98.04% polyamine, based on the actual solids. An improved performance of the use of compositions containing from about 0.1% -10.0% by weight of MFAC to 99.9% -90.0 by weight of polyamine was generally obtained.

TABLE IV Example Proportion of MFAC Turbidity Dose of Polyamine in the Coagulant x filtered NTU Composition 20 100 parts Polyamine 50 280 21 0.1 parts of MFAC 50 244 99.9 parts of Polyamine 22 0.36 parts of MFAC 50 241 99.64 parts of Polyamine 23 1.96 parts of MFAC 50 211 98.04 parts of Polyamine i 24 3.5 parts of MFAC 50 369 96.5 parts of Polyamine 25 10 parts of MFAC 50 353 90 parts of Polyamine 26 37.5 parts of MFAC 50 > 2000 62.5 parts of Polyamine 27 50 parts of MFAC 50 > 2000 50 parts of Polyamine 28 100 parts of MFAC 50 > 2000 1 ppm of active solids based on process water It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention. Having described the invention as above, property is claimed as contained in the following:

Claims (20)

1. A method for separating suspended solids from a waste stream or natural water, characterized in that it comprises: (i) adding to the waste stream in an amount sufficient to coagulate the solids, a composition comprising polyamine and colloidal polymer melaminaldehyde acid, in a ratio of about 90.0-99.9 parts by weight of polyamine to about 10.0-0.1 parts by weight of the acid colloidal polymer, wherein the polyamine is a reaction product of a secondary amine and a difunctional epoxy compound or a precursor thereof, and (ii) separate the solids from the waste stream or natural water.

2. The method according to claim 1, characterized in that the ratio of the polyamine to the acid colloidal polymer, ranges from about 96.5 to about 99.9 parts by weight of polyamine to about 3.5-0.1 parts by weight of acid colloidal polymer.

3. The method according to claim 1, characterized in that the ratio of the polyamine to the acid colloidal polymer, varies from about 98.0-99.1 parts by weight of polyamine to about 2.0-0.1 parts by weight of acid colloidal polymer.

4. The method according to claim 1, characterized in that the waste stream is treated and the amount of the composition added to the waste stream varies from about .5 to about 150 parts per million, based on the weight of the waste stream.

5. The method in accordance with the claim 4, characterized in that the waste stream is water from the deinking process, produced from the processing of recycled paper.

6. The method in accordance with the claim 1, characterized in that the waste stream or natural water contains colored bodies.

7. The method according to claim 6, characterized in that the color bodies comprise flexographic ink.

8. The method according to claim 7, characterized in that the colored bodies are removed from the waste stream or from natural water.

9. The method according to claim 1, characterized in that the polyamine is a reaction product of dimethylamine and an epihalohydrin or a precursor thereof.

10. The method in accordance with the claim I, characterized in that it also comprises adding an effective amount of a flocculating polymer before separating the solids from the waste stream or natural water.

11. The method according to claim 10, characterized in that the flocculant is an anionic polymer.

12. The method in accordance with the claim 10, characterized in that the anionic polymer is 1) hydrolyzed polyacrylamide or 2) a copolymer of acrylamide with a monomer selected from acrylic acid, acrylate, 2-acrylamido-2-methyl propanesulfonic acid and 2-acrylamido-2-methyl propan sulfonate.

13. The method in accordance with the claim II, characterized in that the anionic polymer contains at least about 2 mole percent of anionic functionality, based on the monomer.

14. The method according to claim 1, characterized in that the polyamine has a molecular weight ranging from about 50,000 to about 1 million.

15. The method according to claim 1, characterized in that the acid colloidal polymer has a molecular weight ranging from about 50,000 to about 175,000.

16. A method for separating suspended solids color bodies from waters of the deinking process, resulting from paper recycling processing, characterized in that it comprises: (i) adding to the process water from about .5 to about 150 parts per million, based on the process water, a composition comprising a polyamine and an acid colloidal polymer of melamine formaldehyde, in a ratio of about 96.5-99.9 parts by weight of polyamine to about 3.5-0.1 parts by weight of an acid colloidal polymer, wherein the polyamine is a reaction product of a secondary amine and a difunctional epoxy compound or a precursor thereof, and (ii) separating the solids and the colored bodies from the process water.

17. A composition, characterized in that it comprises a polyamine and an acid colloidal polymer of melamine aldehyde in a ratio of about 90.0-99.9 parts by weight of a polyamine to about 10.0-0.1 parts by weight of an acid colloidal polymer, wherein the polyamine is a reaction product of a secondary amine and a difunctional epoxy compound or a precursor thereof.

18. The composition according to claim 16, characterized in that the ratio of polyamine to acid colloidal polymer varies from about 96.5-99.1 parts by weight of polyamine to about 3.5-0.1 parts by weight of acid colloidal polymer.

19. The composition according to claim 16, characterized in that the polyamine has a molecular weight ranging from about 50,000 to about 1 million.

20. The composition according to claim 16, characterized in that the polyamine is a reaction product of a dimethylamine and an epihalohydrin or an epihalohydrin precursor.