RU2171233C1 - Industrial effluent treatment process - Google Patents

Abstract

FIELD: waste water treatment. SUBSTANCE: invention, in particular, relates to industrial effluents containing alkali-earth and nonferrous (Cu, Zn, Ni, etc.) metals. Process involves addition of flocculant and carbonization of effluents. Flocculant is nonstoichiometric polyelectrolyte complex formed by cationic polyelectrolyte, namely polydimethyldiallylammonium fluoride, and anionic surfactant, namely sodium dodecylbenzenesulfonate. According to invention, prior to addition of flocculant (0.3 to 4 g per 1 cu. m of effluent), the whole effluent is subjected to continuous carbonization with carbon dioxide oriented at an angle toward industrial effluent stream. EFFECT: accelerated purification and increased degree of clarification. 2 cl, 2 tbl, 3 ex

Description

 The invention relates to the field of purification of industrial effluents containing alkaline-earth and non-ferrous metals, including the introduction of a flocculant and carbonization of effluents, and can be used to increase the degree of purification of effluents from compounds of copper, zinc, nickel and other non-ferrous metals, reduce water hardness and return it in the production of non-ferrous metal processing plants (OCM), as well as metallurgical and other industries.

 Known methods for treating industrial effluents, according to which to intensify the process of water clarification, a precipitant is added to them to precipitate alkaline earth metal carbonate (EP 672624 A1, C 02 F 1/52, published. 1995).

 Closest to the invention is a method for treating industrial effluents containing alkaline earth and non-ferrous metals, including the introduction of a flocculant (US 5632901 A, C 02 F 1/52, published. 1997).

 The main disadvantage of this method is the insufficient degree of purification of effluents from hardness salts, which does not allow their use in a closed reverse cycle.

 The invention solves the problem of intensifying the process of industrial wastewater treatment, i.e. increase in cleaning speed and degree of clarification.

 In order to achieve the indicated technical result, in the method for purifying industrial effluents containing alkaline earth and non-ferrous metals, including introducing a flocculant and carbonizing the effluents, according to the invention, a non-stoichiometric polyelectrolyte complex — NPEC formed by a cationic polyelectrolyte — polydimethyl diallylammonium fluoride and anionic surfactant ( Surfactant) - sodium dodecylbenzenesulfanate. In addition, before the introduction of the flocculant, the entire runoff undergoes continuous carbonation, carried out by carbon dioxide, directed at an angle towards the flows of industrial effluents.

The amount of flocculant used is 0.3 - 4 g per 1 m ^{3 of} industrial effluents.

 To obtain NPEC, aqueous solutions of the components are drained, the formation of the complex is monitored using sedimentation analysis and measuring the molecular weights of the compounds.

 The resulting complexes were used as a flocculant to clarify the effluents of the OTsM plant. The concentration of contaminants was determined by the gravimetric method. The optimal range of concentrations of the complex used as a flocculant was determined experimentally.

Example 1. A complex of sodium dodecylbenzenesulfanate was prepared, on the one hand, and polydimethyl diallylammonium fluoride, on the other, with a ratio of the former to the norm of 0.16. To obtain it, 10 mg of a 0.142% surfactant solution was added to 10 ml of a 0.1% aqueous solution of polydimethyl diallylammonium fluoride with a molecular weight of 2 • 10 ⁵ and a sedimentation coefficient of 1.677. The result was an NPEC with a molecular weight of 9 • 10 ⁵ and a sedimentation coefficient of 1.915, which proves the individuality of the NPEC.

After 5 l of technological effluents from the neutralization center of the OTsM plant containing 0.5 mg / l Cu ²⁺ , 0.6 mg / l Zn ²⁺ , 0.4 mg / l Ni ²⁺ , 160 mg / l Ca ²⁺ , 50 mg / l Mg ²⁺ , carbon dioxide flow was bubbled for various periods of time. The wastewater treated in this way was sent to sedimentation tanks. The experimental results are given in table. 1.

 It can be seen from the table that with an increase in the time of carbon dioxide bubbling through drains, the concentration of contaminants in them noticeably decreases, but even after 4 hours of bubbling, the residual concentration of impurities does not satisfy the requirements for circulating water.

 Example 2

To 5 l of technological effluents of the neutralization station of the OTsM plant containing 0.5 mg / l Cu ²⁺ , 0.6 mg / l Zn ²⁺ , 0.4 mg / l Ni ²⁺ , 160 mg / l Ca ²⁺ , 50 mg / l Mg ²⁺ , certain quantities of the obtained flocculant were added with stirring, after which the effluents were sent to a sump. The experimental results are given in table. 2.

The table shows that an increase in the concentration of flocculant to 0.2 g / m ³ does not lead to a noticeable increase in the degree of clarification of effluents. With an increase in the concentration of flocculant to 4 g / m ³ there is a significant increase in the degree of clarification. Further addition of flocculant not only does not improve the treatment of effluents, but even worsens it. The table also shows that using only flocculant as an intensifier for clarification does not allow returning effluents to the reverse cycle.

 Example 3

The flow of neutralized industrial effluents from the rolling shops at the neutralization station is directed to the sump. Pipes with cut holes are laid along the bottom of the tray connecting the mixing chamber to the flocculation chamber, through which the entire stock is sparged with carbon dioxide at an angle towards the flow of industrial effluents. In the flocculation chamber, the above-described flocculant with a concentration of 3 g per 1 m ^{3 of} effluent is introduced into the effluent. Samples of treated effluents were taken at the outlet of their radial sedimentation tanks. An analysis of overflow from sedimentation tanks gives the following results: the residual concentration of copper ions in purified water is 0.09 mg / l, zinc ions 0.14 mg / l, nickel ions 0.07 mg / l, calcium ions 35 mg / l, magnesium ions 18 mg / l. The resulting concentrations of pollution satisfy the requirements for closed circulating cycles of industrial enterprises.

Thus, the use of the invention provides, in comparison with known methods, the following advantages:
- deeper wastewater treatment at the same settling time, which is especially important when settling facilities operate in a closed reverse cycle;
- the possibility of reducing the settling time, i.e. reducing the size of the sump (saving energy, floor space) with the same efficiency of the sludge facilities.

Claims (2)

 1. A method of purifying industrial effluents containing alkaline earth and non-ferrous metals, including the introduction of a flocculant, characterized in that a non-stoichiometric polyelectrolyte complex of polydimethyl diallylammonium fluoride and sodium dodecylbenzenesulfonate is introduced as a flocculant, while the entire stock is subjected to continuous carbonization before introducing the flocculant, we carry out continuous carbonization, angle towards the flows of industrial effluents. 2. The method according to claim 1, characterized in that the amount of flocculant is 0.3-4 g per 1 m ^{3 of} industrial effluents.

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