RU2092452C1 - Method of purifying water for household consumption - Google Patents

Abstract

FIELD: water treatment. SUBSTANCE: water is passed through membrane filter element, ozonized, passed through carbon filter, and ozonized once again, the second ozonization step utilizing excess ozone from the first ozonization step. Method can be used for fine cleaning of tap water with high pollution degree. EFFECT: increased purification degree. 2 cl, 1 dwg, 1 tbl

Description

 The invention relates to the field of drinking water supply and can be used for deep purification of tap water in a domestic environment.

 Currently, the preparation of drinking water is carried out at centralized wastewater treatment plants, which have a limited set of devices designed to remove certain groups of contaminants. At such facilities it is often impossible to completely remove all components that pollute natural water, since its treatment is largely determined by anthropogenic impact. In addition, the deterioration in the quality of drinking water prepared at drinking water treatment plants is due to the effect of re-contamination, for example, when purified water passes through pipelines from treatment plants to the consumer.

 Currently known methods for the purification of tap water in domestic installations do not allow to remove all impurities found in tap water after its central processing.

 There is a way to purify tap water with ozonation [1] Due to the high oxidizing potential of ozone, many organic compounds (humic acids, organochlorine and organometallic compounds, etc.) are oxidized. Ozonation removes odors and flavors of water released by certain algae, organic substances and microorganisms, phenols, sulfur and cyanide compounds, petroleum products, pesticides and other substances are oxidized.

 The disadvantage of this purification method is that during the treatment of water with ozone, the oxidation products of substances polluting the water remain in the purified water. The substances formed as a result of oxidation are not only oxides and hydroxides, but also difficult-to-identify compounds, the toxicity of which may be higher than the toxicity of the starting materials. In addition, due to the high content of contaminants in tap water, some of them do not have time to oxidize and remain in the treated water.

The closest technical solution to the claimed is a method of purification of tap water, laid the foundation for the operation of the membrane household appliance "Trickle". The method consists in the passage of water under pressure through a roll filter element (membrane filter) and an activated carbon cartridge (carbon filter) [2]
However, this method does not allow to obtain deep water purification from low molecular weight organometallic compounds. As the analyzes showed, iron-organic complexes, weakly hydrated ions and molecules with relatively small sizes are not retained by filtration membranes and a carbon filter.

With increased color and oxidation of the source water, iron (2 ⁺ ) binds to organic matter in a complex that “slips” into the filter. Therefore, in conditions of severe water pollution, the degree of water purification specified in the instruction manual (99%) cannot be obtained.

 The objective of the patented technical solution is to protect public health by preventing toxic compounds from water from entering the human body. Currently, up to 40% of all diseases associated with the environmental situation are caused by the consumption of substandard water.

 The technical result that can be obtained in the process of implementing the claimed method of water purification is that it allows you to remove toxic contaminants from a multicomponent water system, including hard-to-recover substances, as well as salts of heavy and non-ferrous metals, complex compounds of iron with organic substances, those. The claimed method is applicable for water purification with an initial high degree of pollution.

 In order to achieve the indicated technical result in a method for treating household water, which includes the sequential passage of water through a membrane filter element and a carbon filter, in accordance with the invention, immediately after the membrane filter element and the carbon filter, the water is ozonized.

 To reduce ozone consumption and increase the degree of safety of the method (to reduce the emission of ozone into the atmosphere), water ozonation after a carbon filter is carried out by introducing into the water an excess of ozone left after the membrane filter element.

 In order to achieve the specified result in water purification for domestic use in accordance with the invention, immediately after the membrane filter element and the carbon filter, the water is subjected to sequentially ozonation. A decrease in ozone consumption and an increase in the degree of safety of the implementation of the water treatment method (reduction of ozone emission into the atmosphere) is achieved by introducing an excess of ozone remaining during ozonation of water after the membrane filter element.

 The invention consists in the following.

 When passing through the membrane filter element, suspended solids, microorganisms, high molecular weight organic compounds, hydrated ions are removed from the water. In addition, salts of heavy metals in the form of hydroxide precipitates are retained by 95%. However, organometallic compounds (mainly organometallic in which iron has a valency of 2) do not linger on the membrane element.

 Water passing through the membrane is ozonized in a contact tank, where ozone is supplied from the ozonizer. In the contact tank, the oxidation of organic substances that are not retained on the membrane filter occurs, the transition of ferrous to ferric, the formation of iron hydroxides and heavy metals. Due to the fact that the water passing through the filtration membrane contains significantly less contaminants than the source water, the process of oxidation of contaminants is more complete and a smaller dose of ozone is required, and the excess of ozone is not emitted into the atmosphere, but is used for reprocessing water.

 After ozonation, water containing oxidation products enters the charcoal filter. Activated carbon, which has a high sorption ability, precipitates metal hydroxides formed during ozonation and incompletely oxidized organic compounds. Due to the fact that the content of contaminants in the water entering the carbon filter is small, the duration of its working filter cycle increases. However, the water after the carbon filter has an increased bacterial contamination. Therefore, to improve quality, it is ozonized. Moreover, at this stage, the water is treated with excess ozone remaining after primary ozonation.

 The proposed sequence of water treatment operations (filtering through a membrane filter, ozonation, sorption of contaminants on a carbon filter and secondary ozonation) provides the most effective water purification.

 An example implementation of a method of water purification.

 The drawing shows a diagram (sequence of operations) of the passage of water through the treatment device.

 Water from a water tap is supplied to the membrane filter 1. The productivity of filter 1 is 5-6 l / h at a pressure in the supply network of 1-2 atm. Next, the water enters the contact tank 2 (V = 2 l), where ozone is supplied from the ozonizer 4 (dose 1 mg / l), where the primary ozonation of water occurs. As a result of the process, organic and mineral substances remaining in the water after the membrane filter are almost completely oxidized.

 Next, the water goes to a charcoal filter 3, where the products of ozonolysis are adsorbed. In order to increase the safety of the device, water is subjected to secondary ozonation by supplying an excess of ozone from the contact vessel 2 to the carbon filter 3 filtrate. Thus, the probability of pathogens and organic substances entering the final product is prevented. It is possible to supply ozone either directly to the carbon filter housing 3 (see drawing), or in a separate container for collecting the filtrate (not shown in the drawing).

 Quality indicators of purified water are given in the table.

The advantages of the proposed method:
1. Commonly used methods of household water purification, including those implemented in imported installations, are designed for water having an initial sufficiently low degree of pollution, the inventive method is applicable for water with a high initial degree of pollution.

 2. The quality of the produced water is improved, namely organoleptic and bactericidal indicators.

 3. There is both ozone saving for repeated ozonation of water, and the harmful effect of ozone on the cleanliness of the surrounding air and, accordingly, on the human body, is reduced.

Claims (2)

 1. A method of purifying water for domestic consumption, comprising the sequential passage of water through a membrane filter element and a carbon filter, characterized in that immediately after the membrane filter element and the carbon filter, water is ozonized.  2. The method according to p. 1, characterized in that for the ozonation of water after a carbon filter, an excess of ozone is used after the membrane filter element.

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