RU2315004C1 - Method of decontamination of the water - Google Patents

Abstract

FIELD: different branches of the national economy; methods of the water decontamination in the drinking water supply systems.

SUBSTANCE: the invention is pertaining to the methods of the water decontamination with the help of the chlorine-containing reactants and may be used predominantly in the field of the drinking water supply systems. The method of decontamination of the water provides for injection in it of sodium hypochlorite, which is produced by dissolution in the water of the sodium chloride and by electrolysis of the formed solution. At that the part of the water, which is sent to production of the sodium hypochlorite and compounds 0.04-0.06 % from the total amount of the being decontaminated water is exposed to purification from the organic substances. The technical result of the invention consists in the decreased share of the chlorine-containing compounds in the treated water.

EFFECT: the invention ensures the reduced share of the chlorine-containing compounds in the decontaminated water.

1 tbl, 1 ex

Description

The invention relates to methods for disinfecting water with chlorine-containing reagents and can be used mainly in the field of drinking water.

A known method of disinfecting water with chlorine gas, comprising dissolving chlorine gas, usually in tap water and the subsequent introduction of chlorine water into disinfected water [1].

This method is quite simple to implement and reliable in the achieved effect.

At the same time, the method is characterized by a number of significant drawbacks related both to the formation of organochlorine compounds (in particular, chloroform) during the disinfection process, as well as to the possible public health hazard of chlorine gas during its transportation and storage.

There is also known a method of disinfecting water with chlorine gas, which includes preliminary purification of disinfected water from organic substances with the subsequent introduction of chlorine water into it [2].

Using the method allows to significantly reduce the amount of organochlorine compounds formed during disinfection.

However, the method is very expensive because of the need to clean the entire volume of disinfected water from organics, and also (as discussed above) is associated with the danger of chlorine gas during its transportation and storage.

The closest in technical essence and the achieved result is a method of disinfecting water, including its preliminary purification from organic substances and the subsequent introduction of sodium hypochlorite obtained by dissolving sodium chloride in water and electrolyzing the resulting solution [3].

This method compared with the above is significantly safer.

However, the implementation of the method is also associated with significant costs due to the need to clean from organic substances the entire volume of disinfected water.

The objective is to reduce the content of organochlorine compounds in the disinfection of water and ensure the efficiency of the process.

The technical result consists in the fact that the content of organochlorine compounds, for example, chloroform, is reduced in the treated water.

The problem is solved according to the invention in that the disinfection of water is carried out by introducing sodium hypochlorite into it, which is obtained by dissolving sodium chloride in water and electrolyzing the resulting solution, while the water that goes to dissolve sodium chloride to produce sodium hypochlorite is 0.04- 0.06% of the total volume of disinfected water is subjected to purification from organic substances.

Example.

The water of the surface water source, characterized by: color 32 degrees, turbidity 6.0 mg / l, humic acid content 320 μg / l, sulfonic acids 6420 μg / l, is subjected to coagulation and clarification by filtration through a layer of quartz sand.

The filtrate is disinfected with sodium hypochlorite at a dose of 1.8 mg / l of active chlorine.

In disinfected water, the value of chloroform (the substance most characteristic of the resulting organochlorine compounds) is chromatographically determined. At the same time, the criterion for the effectiveness of the method is the possibility of obtaining a chloroform content of not more than 30 μg / L in disinfected sodium hypochlorite water.

Spend three series of experiments:

- in the first series, the filtrate is disinfected with sodium hypochlorite obtained by dissolving sodium chloride in water (previously purified by filtration through a layer of quartz sand) and subsequent electrolysis of the solution;

- in the second series, the filtrate is additionally purified through a layer of activated carbon (for a deeper extraction of organic substances from water), after which it is disinfected with sodium hypochlorite obtained by dissolving sodium chloride in water (after purification by filtration through active charcoal) and subsequent electrolysis of the solution;

- in the third series, the filtrate is disinfected with sodium hypochlorite obtained by dissolving sodium chloride in water, additionally purified from organic substances by filtration through activated charcoal, followed by electrolysis of the resulting solution.

The results of the experiments are presented in the table.

Series of experiments The amount of chloroform formed in water, mcg / l I 60-70 II 10-13 III 16-20

As can be seen from the table, the main amount of chloroform in disinfected water is formed not when sodium hypochlorite is introduced into disinfected water, but at the stage of electrolysis of sodium chloride solution, when the content of active chlorine in hypochlorite is from 6 to 10%.

Considering that 0.04-0.06% of the total volume of water is spent on the production of hypochlorite, obtained directly at water treatment plants, it is this amount of water that should be deeply cleaned of the organic substances contained in it in order to reduce the amount with minimal costs organochlorine compounds formed during the disinfection of water with sodium hypochlorite.

Information sources

1. A.A. Kastalsky, D.M. Minz. "Preparation of water for drinking and industrial water supply." M., "Higher School", 1962, p. 317.

2. Water supply II. Association of Civil Engineers of Finland. The New Journal, St. Petersburg, 2005, p. 425-426.

3. Water supply II. Association of Civil Engineers of Finland. "New Journal", St. Petersburg. 2005, S. 427-428 (prototype).

Claims (1)

The method of disinfecting water by introducing sodium hypochlorite into it, which is obtained by dissolving sodium chloride in water and electrolyzing the resulting solution, characterized in that the part of the water that goes into the production of sodium hypochlorite is 0.04-0.06% of the total volume of disinfected water subjected to purification from organic substances.