RU2570085C2 - Method and device for water decontamination - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: group of inventions can be used in water pipeline - sewage constructions as well as for household and medical purposes for water decontamination. To realise the method water solution of sodium hydroxide is introduced into water to be processes before introduction of chlorinated water. Additionally method includes introduction of water solution of sodium hydroxide after introduction of chlorinated water. Installation for water purification contains electrolyser of sodium chloride water solution, means for obtaining chlorinated water by dissolution of gaseous chlorine in water, means for introduction of chlorinated water into water, means for introduction of sodium chloride water solution into the same water, located downstream before means for chlorinated water introduction. Device additionally contains means for introduction of sodium chloride water solution, located after means for chlorinated water introduction.

EFFECT: inventions provide increased efficiency of water decontamination.

4 cl, 2 dwg, 1 tbl, 9 ex

Description

The invention relates to methods and devices for disinfecting water, intended for use in domestic, medical and other purposes, and can be used, in particular, in plumbing installations.

Known methods of disinfecting water by introducing into the water chlorine water obtained by dissolving in water gaseous chlorine from cylinders (Abramov NN Water supply. M .: Stroyizdat, 1982, S. 284-287). The need for the use of chlorine in cylinders and their transportation from the place of production to the place of consumption is associated with a significant risk of leakage of highly toxic chlorine.

A known method of disinfecting water, comprising introducing into the water chlorine water obtained by dissolving in water the chlorine released during the electrolysis of a solution of sodium chloride (RU 2090519, C02F 1/76, C25B 1/26, 1997).

There is also known a method of disinfecting water, comprising introducing into the water gaseous chlorine released during the electrolysis of a sodium chloride solution, and then introducing into the disinfected water an aqueous solution of sodium hydroxide obtained simultaneously with chlorine during the electrolysis of a solution of sodium chloride (RU 2058267, C02F 1/467, 1996 )

Closest to the proposed is a known method of disinfecting water, including introducing into the water chlorine water obtained by dissolving in water chlorine extracted during the electrolysis of a sodium chloride solution, and an aqueous sodium hydroxide solution obtained simultaneously with chlorine during the electrolysis of a sodium chloride solution and mixed with chlorine water in the process of its formation during the dissolution of chlorine (RU 2281252, C02F 1/467, 2006). As a result of the implementation of this method, the disinfecting agent introduced into the water contains sodium hypochlorite. The method is characterized by a rather high efficiency of water disinfection in relation to certain types of microorganisms.

Known installations for disinfecting water containing means for producing chlorine water by dissolving gaseous chlorine in water from cylinders, and means for introducing chlorine water into water to be disinfected (Abramov N.N. Water supply. M .: Stroyizdat, 1982, p. 284-287).

A known installation for disinfecting water, containing an electrolyzer for producing chlorine by electrolysis of an aqueous solution of sodium chloride, a means for producing chlorine water by dissolving gaseous chlorine from the electrolyzer in water, and a means for introducing chlorine water into water to be disinfected (RU 2090519, C02F 1 / 76, C25B 1/26, 1997).

There is also known a device for disinfecting water, containing an electrolyzer for producing chlorine and an aqueous solution of sodium hydroxide by electrolysis of an aqueous solution of sodium chloride, an ejector for introducing gaseous chlorine from the electrolyzer into the disinfected water, means for introducing an aqueous solution of sodium hydroxide into the water to be disinfected located in the direction of the flow of water to be disinfected after the ejector (RU 2058267, C02F 1/467, 1996).

Closest to the proposed is a known installation for disinfecting water, containing an electrolyzer to produce chlorine and an aqueous solution of sodium hydroxide by electrolysis of an aqueous solution of sodium chloride, an ejector to produce chlorine water by dissolving chlorine gas from the electrolyzer in water, while introducing an aqueous solution of sodium hydroxide , means for introducing a mixture of chlorine water and an aqueous solution of sodium hydroxide into water to be disinfected (RU 2281252, C02F 1/467, 2006).

The objective of the invention is to increase the efficiency of the process of disinfecting water.

To solve this problem, a method for disinfecting water is proposed, comprising introducing chlorine water and an aqueous solution of sodium hydroxide into water, characterized in that the aqueous sodium hydroxide solution is introduced into the water before the introduction of chlorine water. The additional introduction of an aqueous solution of sodium hydroxide after the introduction of chlorine water increases the effectiveness of disinfection.

To solve this problem, a water disinfection apparatus is also proposed, comprising an electrolyzer for producing chlorine and an aqueous solution of sodium hydroxide by electrolysis of an aqueous solution of sodium chloride, a means for producing chlorine water by dissolving chlorine gas in water, a means for introducing chlorine water and an aqueous solution of sodium hydroxide into water to be disinfected, characterized in that the means for introducing an aqueous solution of sodium hydroxide are located in the direction of the flow of water to be disinfected iju to means for introducing chlorine water. The installation may further comprise means for introducing an aqueous solution of sodium hydroxide located in the direction of the flow of water to be disinfected, after means for introducing chlorine water.

The technical result of the invention is to increase the degree of disinfection of water in relation to indicators that are controlled in terms of its sanitary condition — total microbial number (TBC), total coliform bacteria (OKB), thermo-tolerant coliform bacteria (TKB), coliphages, spores of sulfite-reducing clostridia (IBS) .

It was unexpectedly discovered that the introduction of an aqueous solution of sodium hydroxide into the water to be disinfected, before the introduction of chlorine water, ceteris paribus (the concentration of chlorine in chlorine water and its dosage) increases the degree of purification of water from these microorganisms, and also improves the process of coagulation of colloidal impurities. Accordingly, to achieve the required degree of water purification that meets sanitary requirements, the introduction of a sodium hydroxide solution according to the proposed method allows to reduce the amount of chlorine that must be introduced into the water to disinfect it, and therefore, to reduce the number of chlorine compounds in the treated water.

The time period between the introduction of a solution of sodium hydroxide and the introduction of chlorine water may be short, for example, of the order of tens of seconds or several minutes. It is possible, however, to increase this period, due to the convenient location of the equipment at the water treatment plant, without changing the result.

The invention is illustrated by the attached FIG. 1, 2. In FIG. 1 shows a diagram of the proposed installation that implements the proposed method, FIG. 2 is a diagram of a device (unit) for introducing an aqueous solution of sodium hydroxide into water to be disinfected.

In accordance with FIG. 1 installation includes a membrane electrolyzer 1 with lines 2 and 3 for supplying, respectively, a solution of sodium chloride and water, separators 4 and 5 for separating respectively released chlorine and hydrogen from the liquid phase and lines 6 and 7 for removal of chlorine and hydrogen, an ejector 8 for producing chlorine water based on the tap water flowing through line 9, the water supply line 10 to be disinfected, an intermediate tank 11, a block 12 connected to the separator 5 by line 13, for introducing a solution of sodium hydroxide into the water to be disinfected, cut woir 14 for introducing a solution of sodium hydroxide into water through line 15, a chlorinator 16 connected to an ejector 8 line 17, a pump 18 for supplying water from the tank 14 to the chlorinator 16, lines 19 and 20 for supplying coagulant and flocculant to the chlorinator 16, line 21 to withdraw the disinfected water into the sump, line 22 for introducing the sodium hydroxide solution from block 12 into the water stream passing through line 21.

In accordance with FIG. 2, block 12 for introducing a solution of sodium hydroxide into water to be disinfected consists of a housing 23 in which metering devices 24 and 25 and locking devices 26, 27, 28, 29 and 30 are located.

Installation works as follows. Water to be disinfected, through line 10 through an intermediate tank 11 by gravity enters the reservoir 14. In the membrane electrolyzer 1, the sodium chloride solution is electrolyzed, receiving chlorine gas from the separator 4 with an anolyte admixture, and from the separator 5 - sodium hydroxide solution with a concentration of 5-40 % wt., as well as hydrogen discharged through line 7 outside the installation. In the ejector 8, when chlorine is supplied from the separator 4 via line 6 and water through line 9, chlorine water of the required concentration is formed. The sodium hydroxide solution from the separator 5 is fed through line 13 to the sodium hydroxide solution injection unit 12 through an open shut-off device 28. If necessary, excess solution is diverted outside the installation. In block 12, using shut-off devices 26-30 and metering devices 24 and 25, sodium hydroxide solution is distributed. If the sodium hydroxide solution is intended to be supplied to the water to be disinfected only before the introduction of chlorine water, the shut-off devices 27 and 30 are in the closed position and the solution is fed through the open shut-off devices 26 and 29 by the metering device 24 via line 15 to the tank 14. The treated water from the reservoir 14, the pump 18 is fed into the chlorinator 16, where chlorine water obtained in the ejector 8 is supplied via line 17, as well as coagulant and flocculant along lines 19 and 20. Treated water is diverted via line 21 to sedimentation. If the sodium hydroxide solution is intended to be supplied to the water to be disinfected, and after the introduction of chlorine water, the shut-off devices 27 and 30 are in the open position and the solution is dispensed by the metering device 25 through line 22 to line 21.

If the sodium hydroxide solution is intended to be supplied to the water to be disinfected only before the introduction of chlorine water, block 12 may be absent, and the pipe 13, which is directed directly to the tank, can serve as a means for introducing an aqueous solution of sodium hydroxide into the water to be disinfected. 14 and may comprise a metering device or be self-flowing.

The supply of sodium hydroxide solution to the water to be disinfected after the introduction of chlorine water can be carried out as in line 21, in accordance with FIG. 1, and directly to the upper part of the chlorinator 16, since chlorine water is introduced into its lower part.

Described in accordance with FIG. 1 and 2, a specific embodiment of the proposed installation is intended primarily for use at water treatment plants of water supply systems. The proposed installation can be used for water purification in large tanks, such as swimming pools. In this case, the pipelines of chlorine water 17 and the sodium hydroxide solution 15 and 22 are connected to the pipeline through which the water in the tank is circulated, so that the connection point of the pipe 15 is located in the direction of the circulating flow before and the connection point of the pipe 22 after the connection point pipeline 17.

The invention is also illustrated by the following examples, showing a specific implementation of the method on the installation. Examples 1-4 and comparative examples 5 and 6 at a lower concentration of chlorine illustrate the effect of the introduction of a solution of sodium hydroxide on the process of disinfection of water. Example 7 illustrates the implementation of the proposed method on the proposed installation with the achievement of the necessary sanitary indicators, and comparative examples 8 and 9 - the need to increase the consumption of chlorine in the absence of the introduction of a solution of sodium hydroxide.

EXAMPLE 1. In the membrane electrolyzer 1 electrolysis of a solution of sodium chloride is carried out, receiving chlorine from a separator 4, and from a separator 5 a solution of sodium hydroxide with a concentration of 10% wt. In the ejector 8, when chlorine is supplied from the separator 4 and water through line 9, chlorine water with a concentration of 5 mg / l is formed. Sodium hydroxide solution is introduced into reservoir 14 through block 12 in the amount necessary to create a concentration of 0.038 mg / L. From the tank 14, water is pumped to the chlorinator 16 via the pump 18. The capacity of the pump 18 is adjusted so that the residence time of the water in the tank 14 is 5 minutes. Chlorinator 16 is supplied with chlorine water obtained in an ejector 8, as well as alumina coagulant (0.128 mg / l) and PAX-XL 100 flocculant (15 mg / l) along lines 19 and 20. The water composition before and after disinfection according to this and the following examples is given in the attached table.

EXAMPLE 2. The disinfection process is carried out analogously to example 1 with the difference that the performance of the pump 16 is regulated so that the residence time of water in the tank 12 was 2 minutes

EXAMPLE 3. The disinfection process is carried out analogously to example 1 with the difference that the performance of the pump 16 is regulated so that the residence time of the water in the tank 12 was 7 minutes

EXAMPLE 4. The disinfection process is carried out analogously to example 1 with the difference that from block 12 the sodium hydroxide solution is fed into the tank 14 and line 21 in the amount necessary to create a concentration of 0.038 mg / L.

EXAMPLE 5 (comparative). The disinfection process is carried out in accordance with the prototype: the sodium hydroxide solution is mixed with a chlorine solution in an additional ejector installed on line 17 after the ejector 8, and the mixed solution is fed into the chlorinator 16.

EXAMPLE 6 (comparative). The disinfection process is carried out analogously to example 1, but without supplying a solution of sodium hydroxide.

EXAMPLE 7. The disinfection process is carried out analogously to example 1 with the difference that the amount of chlorine required to produce chlorine water with a concentration of 6 mg / l is supplied to the ejector 8.

EXAMPLE 8 (comparative). The disinfection process is carried out analogously to example 7, but without supplying a solution of sodium hydroxide.

EXAMPLE 9 (comparative). The disinfection process is carried out analogously to example 8, but the concentration of chlorine water is increased to 8 mg / L.

Claims (4)

1. A method of disinfecting water, comprising introducing into the water chlorine water and an aqueous solution of sodium hydroxide, characterized in that the aqueous solution of sodium hydroxide is introduced into the water before the introduction of chlorine water. 2. The method according to claim 1, characterized in that the aqueous sodium hydroxide solution is introduced into the water also after the introduction of chlorine water. 3. Installation for disinfecting water, containing an electrolyzer for producing gaseous chlorine and an aqueous solution of sodium hydroxide by electrolysis of an aqueous solution of sodium chloride, means for producing chlorine water by dissolving gaseous chlorine in water, a means for introducing chlorine water and an aqueous solution of sodium hydroxide into water to be disinfection, characterized in that the means for introducing an aqueous solution of sodium hydroxide are located in the direction of the flow of water to be disinfected, to the means for introduced oia of chlorine water. 4. The installation according to claim 3, characterized in that it further comprises means for introducing an aqueous solution of sodium hydroxide, located in the direction of the flow of water to be disinfected, after means for introducing chlorine water.

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