RU2237024C1 - Waste water treatment process - Google Patents

Abstract

FIELD: waste water treatment.

SUBSTANCE: invention relates to treatment of waste waters from various plants, especially metallurgical plants, to remove suspended materials by the help high-molecular flocculants, the latter in particular being copolymer of (i) anionic high-molecular compound selected from polymerization products of acrylonitrile, ethyl methacrylate, and itaconic acid and (ii) cationic polyelectrolyte, namely polydimethyldiallylammonium fluoride. Copolymer is added in amounts of 0.2 to 0.8 mg per 1 dm³ waste water.

EFFECT: increased waste water purification degree and increased slurry sedimentation velocity, especially in case of treating metallurgical waste waters.

2 cl, 3 tbl, 4 ex

Description

The invention relates to methods for wastewater treatment of various industries, especially metallurgical - sintering, open-hearth, blast furnaces, etc. from suspended solids by a reagent method.

A known method of wastewater treatment, in which the product of the polymerization of acrylic acid in the presence of peroxodisulfate and ammonium nitrate is used as a flocculant. After the introduction of the flocculant, air is purged for 3-5 minutes (SU 1225208).

The disadvantage of this method is the low degree of wastewater treatment.

A known method of wastewater treatment from suspended solids (SU 2051172), where the product of the interaction of polyethylene polyamine and urea, taken in the ratio (3.5-5.0): 1.0, is used as a flocculant.

The disadvantage of this method is the lack of the necessary degree of wastewater treatment.

The prototype of the proposed method is a wastewater treatment method described in (SU 1578083). According to this method, water purification is carried out by introducing into the effluent a flocculant, which is a copolymer of dimethyldiallylammonium chloride with vinylpyrrolidone.

The disadvantage of this method is not satisfying the technological regime (especially for sinter plants) the degree of water purification.

The technical result achieved in the invention is to increase the degree of wastewater treatment.

The specified technical result is achieved as follows.

In the method of wastewater treatment from suspended solids, the water is treated with a flocculant.

The difference of the method is that a copolymer of an anionic high molecular weight compound, which is a polymerization product of acrylonitrile, ethyl methacrylate and itaconic acid, and a cationic polyelectrolyte in the form of polydimethyl diallylammonium fluoride is introduced as a flocculant.

The difference between the method and the fact that the amount of introduced copolymer is 0.2-0.8 mg / DM ³ wastewater.

The resulting copolymer is readily soluble in water, methanol, dimethylformamide. The composition of the resulting copolymer, determined according to elemental analysis and IR spectroscopy, is 30% of the first (anionic) component and 70% of the second (cationic) component. The intrinsic viscosity of the sample obtained copolymer, measured in 1 N. a solution of sodium chloride in water gives a value of 0.65 DL / g

Example 1

To 5 l of wastewater from the open-hearth workshop, containing 0.8 g / dm ³ solid in the pulp, certain amounts of flocculant were added, necessary to obtain its solutions of the following concentrations, mg / dm ³ : 0.05; 0.1; 0.2; 0.4; 0.8; 1.0; 5.0; 10.0 The solutions were mixed and sent to the sump. The concentration of suspensions in this and in all subsequent examples was determined both by the gravimetric method and by light absorption. The results are shown in table 1.

From the table. Figure 1 shows that in the range of flocculant concentrations 0-0.1 mg / dm ^{3, the} rate of clarification of wastewater does not increase significantly, with an increase in flocculant concentration from 0.2 to 0.8 mg / dm ³ , a significant increase in the rate of sedimentation of suspensions occurs. With an increase in flocculant concentration above 0.8 mg / dm ^{3, the} rate of water clarification practically does not change.

Example 2

A similar experiment was conducted with the effluents of the blast furnace. The solid content in the pulp is 1.1 g / dm ³ .

From table 2 it is seen that, as for wastewater of the open-hearth production, in the range of flocculant concentrations 0-0.1 mg / dm ^{3, the} rate of clarification of wastewater does not increase significantly, with a further increase in flocculant concentration to 0.8 mg / dm ³ increased sedimentation rate. With a further increase in the concentration of flocculant, the rate of water clarification changes slightly.

Example 3

A flocculant with a concentration of 0.4 mg / dm ³ is introduced into the wastewater of sinter production containing 5-7 g / dm ³ solid in the pulp. Wastewater with flocculant is mixed and sent to the sump. Determination of the concentration of suspended solids in water is carried out 1 hour after the start of sedimentation. It was established that the residual concentration of suspended matter in water does not exceed 0.030 g / dm ³ . For comparison, it is shown that without the use of a flocculant, the residual concentration of suspended solids in wastewater is 0.19-0.21 g / dm ³ , and when using the prototype (0.4 mg / dm ³ ) - 0.085 g / dm ³ .

Example 4

To 5 l of wastewater rolling mill containing 0.6 g / DM ³ solid in the pulp with stirring, add certain amounts of the proposed flocculant and mix the system for 5 minutes After stirring, the mixture is clarified by settling for 20 minutes and samples are taken for analysis. The residual content of suspended solids is determined in the treated water. For comparison, data are given when using the prototype (see table 3).

Thus, from the above examples, we can conclude that the proposed method leads to a significant increase in the degree of wastewater treatment in metallurgical industries.

Claims (2)

1. A method of treating wastewater from suspended solids by treatment with a flocculant, characterized in that a copolymer of an anionic high molecular weight compound, which is a polymerization product of acrylonitrile, ethyl methacrylate and itaconic acid, a cationic polyelectrolyte in the form of polydimethyl diallylammonium fluoride, is introduced as a flocculant. 2. The method according to claim 1, characterized in that the amount of introduced copolymer is 0.2-0.8 mg / DM ³ wastewater.