CS251897B1 - Method of waters' treatment and purifying - Google Patents

Abstract

Basis of water treatment and purification is the addition of an aniorgam auxiliary coagulant organic flocculant, sodium or potassium salts of an alkyl ester copolymer a, β ethylenically unsaturated acid, where alkyl contains from 1 to 8 carbon atoms and vinyl benzene-containing monomer core *, wherein the degree of neutralization is in the range 0.45 to 0.60 and the molecular weight of the cocopolymer within 1. 10-6 to 8. 106. Use the addition of flocculant is preferred at pH 6 to 9 and 0.05 to 2.0 mg. I-1 when the highest sedimentation rate is achieved and the lowest turbidity of purified water.

Description

The invention relates to a process for the treatment and purification of water by inorganic salts with the addition of a synthetic organic flocculant which accelerates the sedimentation of sludge and eliminates the possibility of agglomerate destruction.

In the treatment and purification of water with inorganic salts having the function of a coagulant, soluble high molecular weight organic polyblulants have been used for a long time, dosed usually into purified water up to ρΰ of the inorganic coagulant. The addition of these flocculants increases the size of the floccules formed by the action of inorganic salts or increases their specific gravity to a certain extent, thereby helping to accelerate the sedimentation of the resulting agglomerates and hence the quality of the liquid to be precipitated. The addition of organic flocculants is also intended to increase the resistance of the flocs to shear forces occurring in the Repair or Treatment Plant.

Synthetic polyacrylamide-based organic flocculants are the most widespread. In particular, anionic flocculants such as hydr (lysed pplyacrylamides or copolymers of acrylaimide and acrylic acid) are widely used. However, their effect is less than that of polyacrylamide derivatives and is therefore rarely used.

High molecular weight organic substances with good flocculating effects usually have a linear or low-branched structure of the basic macromolecule long enough for the milling to be effective. They contain sufficient active groups to bind to the surface of the suspended particles.

The problem remains that high-molecular-weight substances with molecular sizes in excess of a certain size are poorly soluble, thermodynamically unstable in solution, and their effectiveness is limited by the achievable concentration in the solution on one side and the inadequate size of the macromolecule on the other. Commercial derivatives poilyakrylamidu have practical range n®lekulové weight of 10 ⁵ to 10 ⁷ and are considered the most effective, since in this molecular weight, yet do not exceed the solubility limit.

Anionic polymeric flocculants usually have incorporated in their structure carboixyl groups —COOH, which in many cases have a greater adsorption capacity than —CONH2 groups. The carboxyl group is capable of ionizing, which increases the efficiency of anionic flocculants, which must have a certain degree of ionization to function. At a low degree of ionization, the macromolecule chains are tightly coiled, almost spherical, while at a high degree of ionization they are fully developed and almost immovable.

In both cases, the molecule loses its ability to form bridges and its flocculation ability decreases strongly.

Synthetic organic flocculants are produced as solids, in the form of powders, flakes or granules. When powdered products are dried, elevated temperatures may result in internal crosslinking, chaining and branching, which reduce the flocculation efficiency of the formulation. In addition, these formulations are difficult to transfer into aqueous solutions. Handling of solutions is difficult, dissolution time is 60 to 120 minutes or even more and requires relatively complicated equipment, especially intensive mixing, because good, perfect and fast dissolution is an important prerequisite for their successful application in water purification. This intensive mixing, however, carries the risk of destroying the polymer chain into small, ineffective units by shear forces during intensive mixing. This also clearly reduces the resulting flocculation efficiency of the polymers.

The aforementioned drawbacks are solved by a water purification and treatment process based on the use as a sodium flocculant or a potassium salt of an alkyl ester of an alpha, beta-ethylenically unsaturated acid copolymer wherein the alkyl contains 1 to 8 carbon atoms and a vinyl benzene-containing vinyl monomer such as For example, styrene or α-methylstyrene. The degree of neutralization of the copolymer is in the range of 0.45 to 0.60 and the molecular weight in the range of 1. 10 ⁶ to 8. 10 ⁶ .

This flocculant is added to the purified water in an amount of 0.05-2.0 mg / l at pH 6-9 after the inorganic coagulant.

The organic polymeric flocculant according to the invention consists of a combination of esterified and ionized polymer, which has proved to be more advantageous than the types of flocculant used hitherto. In particular, the degree of neutralization makes it possible to precisely regulate the ratio between the ionization of the polymeric flocculant solution and the non-ionized part, whereby the shape of the macromolecule in the solution and thus its flocculation efficiency is advantageously adjusted. Furthermore, the polymeric flocculant defined according to the invention is very soluble in water 1 at a relatively high molecular weight and can be used in the water industry in the form of a concentrated aqueous solution. This not only greatly reduces the time required to prepare the working mixtures, but also completely eliminates the risk of shear deformation and destruction of the flocculant and the agglomerates formed by it.

In practice, the dosing of the concentrated flocculant solution is carried out at such points of the device as to ensure its uniform and rapid distribution throughout the volume of the treated water. The doses of flocculant are converted to 100% active substance depending on the concentration of the working concentrated solution of the formulation.

The largest elongation of the molecule ani; The other polymer of the invention occurs in a neutral, my weakly alkaline environment. By decreasing the pH, the degree of dissociation decreases, thus the charge density and the degree of macromolecule unfolding.

The method of treatment and purification of the waters according to the invention is described in more detail in the examples, which, however, are neither limited nor exhausted.

Examples.

Example 1

By treatment of river water from Svratka a suspension of ferric flakes was formed by adding 55 mg. I ' ¹ FeCh. 6 řhO. In 1 minute

Relat. turbidity in the AB sample after the addition of ferric chloride »the purified river water sample was divided into three parts, one was left in its original state (Aj, the other pH was adjusted to 9,85 and organic flocculant, sodium ethylmaleinate-styrene copolymer added) degree of neutralization of 0.48, a molecular weight of 2.3. 10 ⁶ in an amount of 0.2 mg. · I ¹ calculated on the active substance content. the flocculant was added as an 8% aqueous solution (BJ. the third part of the sample, designated (C ) was treated with an equal amount of flocculant, but at pH 8.5.

The effect of flocculant addition was observed over time as the relative turbidity of the purified water and compared to each other for all three sample sections. The measurement results were as follows:

Sedimentation time

C (min)

0.96 0.69 0.68 0.52 0.38 0.29 0.24 0.20

0.39 1.5 0.19 2.5 0.17 5.0 0.16 15.0

During flocculation with the formulation according to the superior flocculant, it greatly accelerated the sedmentation, especially at pH 8.5 and in the first minutes of the process, when the steady state of Sample C was reached after almost 2.5 minutes.

Example 2

In the same manner as the poodle of Example 1, a flake suspension was formed by adding 55 mg. Γ ¹ ferric chloride and the sample was equally divided into samples A, B and C with pH adjustment according to Example 1. Coipotymer, consisting of potassium salt of butylitacomate and styrene, was added as a flocculant to samples B and C at a concentration of 0.2 mg. Γ ¹ (100 per cent dry matter). The degree of neutralization of the copolymer was 0.58 and the molecular weight was 8. 10 ^p . Sedimentation rate of ferric flakes was measured in all samples and compared with each other. The found maximum sedimentation velocities (in mm. S ^_1 ) for individual samples are as follows:

A 0,7

B 1,2

C 1.9

Obviously, the use of the composition of the invention gives a significantly higher rate of sedimentation of the flake cloud.

Example 3

By the same procedure as in Example 1, a flake suspension was formed by adding 55 mg. This ferric chloride · ¹ »the river and always sample was divided into three parts according to the uniform adjustment of the pH to 8.5. The first part remained in its original state, the second part was flocculated and added 0.2 mg. 'Γ' polyacryliamide with molecular weight 1. . 10 ^5, the third addition of ethyl native salt of maleic acid in the form of copolymers with styrene ,, molecular weight third 10 ⁶ and a degree of neutralization of 48% in an amount of 0.2 mg. I ¹ in the content of the active ingredient. For all three samples, the percentage of turbidity trapping was measured at different slurry velocities in a rectangular lamella (1.5 m long, 0.5 µl with 60 ° inclination angle). Flow velocities were considered and measured as mean flow velocities. The following were measured; values:

% capture of haze forming agents in the sample

ABC

Mean flow velocity in mm. s ^_1

72 87 90 0.5 70 85 89 0.8 68 85 88 1.0 66 84 87 1.4

In the flocculation by the preparation according to the invention, a higher effect was permanently obtained, irrespective of the speed of the water flow through the lamella.

Example 4

The river water from the Svratka River was clarified with 55 mg of ferric chloride. 1 ^_1 INLA clarifier model with reciprocating paddle (CSSR Pat. 137,876) provided with baffles in a space interposed čkovacíbo cloud. When added to Part B polyacrylamide in an amount of 0.2 mg. . Even if part C ^-1 potassium -oktylitakonátu copolymer with styrene in an amount of 0.2 mg. Γ ¹ (calculated on 100% active substance content), turbidity in the treated water was measured in dependence of the rising water velocity at the level of the flocculent cloud. The following values were measured:

AND Residual turbidity (ZF) in the sample (B) C Ascending speed (mm. S ¹ ) 23.0 22.4 19.8 1.0 22.6 18.5 18.1 2,0 21.9 22.1 17.3 3.0 28.2 29.7 22.2 4.0

As can be seen from the table, even with this test, the best results, in particular at high factory compositions according to the invention, showed increasing speeds.

Claims (5)

Process for the treatment and purification of water with inorganic salts, characterized in that the sodium or potassium salt of the copolymer of a moialkyl α, β-ethylenically unsaturated acid copolymer, wherein the alkyl contains 1 to 8 carbon atoms and a vinyl monomer, containing a benzene core, with a degree of neutralization in the range of 0,45 to 0,60 and a molecular weight of. 10® to 8. 10 ⁶ . 2. A process according to claim 1 wherein the organic flocculant is dosed after the inorganic flocculant in an amount of 0.05-2.0 mg. . 1 ^_1 at one or more points of the device, OF THE INVENTION ensuring its good distribution into the entire volume of treated water. 3. A process according to claim 1, wherein the organic flocculant is added at a pH of the treated water in the range of 6 to 9. 4. A process according to claim 1, wherein the .alpha.,. Beta.-ethylenically unsaturated acid is itacoiric acid or mincincincine. 5. A process according to claim 1, wherein the vimylic monomer containing a benzene nucleus is styrene or .alpha.-methylstyrene. Severography, n. P., Plant 7, Most Price 2,40 Kčs