RU2238916C1 - Natural water purification process - Google Patents

Abstract

FIELD: water treatment.

SUBSTANCE: process of treatment of iron-rich natural underground water comprises oxidant treatment, filtration through inert charge, washing of charge, disinfecting of water by UV emission, and transportation of treated water to consumers. Filtration is carried out in countercurrent mode through movable charge bed in filtration apparatus provided with air lift. Charge is washed in the top part of the apparatus simultaneously with filtration, ratio of apparatus operation time in filtration mode to that in simultaneous filtration/washing mode equals (5-1):1. Wash water containing suspended particles is sent to separation stage, after which liquid phase is returned into treatment stage and solid phase is removed from the process. Inert charge is represented by quartz sand fraction 0.3-2.0 mm, which moves with the bed at linear velocity 2 to 10 mm/min, ratio of wash water stream to sand stream in sand washing section being (0.6-2):1. Separation of wash water into solid and liquid phases is accomplished by filtration, simple separation, or settling. Solid phase withdrawn from the process is sent to production of pigments.

EFFECT: enabled wasteless and continuous water treatment process.

5 cl, 1 dwg, 2 tbl, 4 ex

Description

The invention relates to methods for purifying natural groundwater for drinking water supply, especially with a high content of iron.

A known system for cleaning water from iron and manganese, comprising a pumping system for pumping water from a water source, a device for aeration of water, a cleaning tank, consisting of an upper chamber, in which there is a device for washing the middle chamber with filter loading and the lower chamber for purified water . The system also includes a pressure tank and a second pump system for supplying purified water from the pressure tank to the lower chamber, a cleaning tank, from which water is then supplied for washing the charge (WO 95/19937, 07.27.1995).

The disadvantage of the described system is the need to use two pumping systems and two tanks, as well as the frequency of the process: filtering - washing the load.

A known installation for iron removal of water containing an aerator, a contact filter with a floating granular charge and a lower distribution device, a lighting filter with a granular load having a specific gravity greater than the specific gravity of the water to be treated, and with a lower distribution device, as well as a bypass device located between the lower distribution contact and lighting filter devices (RU 2165897, 04/27/2001).

A disadvantage of the known installation is the need to transfer it from the filtration mode with its stop to the washing mode.

There is also known an installation for treating groundwater containing an oxidation unit, a clarification unit, a filtration unit, a regeneration system, an input unit for coagulants and flocculants, while the filtration unit contains filters filled with natural material with weakly basic properties, a natural inert material, and the regeneration system consists of air supply lines connected to the upper layer of the filter loading, drainage lines for regenerating solutions (RU 2187462, 08.20.2002).

However, this installation for the process of regeneration of filtering materials requires stopping the process of filtering water.

A known method of water purification, in which the water treated with reagents, is supplied to the clarification in the lower part of the device with an intensity that provides weighting of the contact mass, then after the expiration of the time of the protective action, the feed water is stopped, and the contaminated contact mass is transported to the upper part of the device, where undergoes rotation, as a result of which the separation of the particles of the precipitate and the contact mass by density under the action of centrifugal forces occurs. The washed grains of the contact mass are precipitated, and the precipitate, together with the spent wash water, is removed from the process (RU 2144512, 01.20.2002).

The disadvantage of this method is the frequency of the cleaning process.

The closest in technical essence and the achieved result is a method of purification of natural water, including its treatment with an oxidizing agent - air, filtering in two stages: first through an inert charge, and then through a sorption and ion-exchange charge, disinfection of water with ultraviolet radiation, washing the load in air-water mode in three stages: first with air, then with an air-water mixture and then with water, purified water is supplied to the consumer, and the resulting washing water is discharged into the sewer or on the natural topography (RU 2087427, 08.20.1997).

The disadvantage of this method is the frequency of the process and its openness, as well as the use of heterogeneous downloads and cumbersome hardware design.

The objective of the present invention is to develop a continuous method of purification of underground natural water with a closed loop and a high degree of purification.

The problem is solved by the described method of purification of natural water, which includes the treatment of water with an oxidizing agent, filtration through inert loading in countercurrent mode through a movable loading layer in a filter device equipped with an air lift, washing of the load, which is carried out in the upper part of the device simultaneously with water filtration, and the time ratio the operation of the filtering device in the filtration mode (t ₁ ) by the time of operation in the simultaneous filtration and washing mode (t ₂ ) are (5-1): 1, wash water, with holding suspended particles are sent for separation, after which the liquid phase is returned for purification, and the solid phase is removed from the process, the purified water is subjected to ultraviolet disinfection and served to the consumer.

Preferably, quartz sand of a fraction of 0.3-2.0 mm is used as an inert load and a linear speed of its movement in the layer of 2-10 mm / min is provided, and the ratio of wash water flows (q ₁ ) and sand (q ₂ ) in the device for washing sand is q ₁ : q ₂ = (2-0.6): 1.

The proposed method can be carried out on the installation depicted in the drawing.

The installation contains:

1 - aerator;

2 - a filtering device equipped with an airlift and a device for washing the load;

3 - ultraviolet emitter;

4 - a device for the separation of washing water;

5 - natural water supply line;

6 - line drain water;

7 - line return of the liquid phase;

8 - line output solid phase;

9 - water supply line to the consumer;

10 - line water supply from the well;

11 - oxidizer feed line;

12 - air supply line for airlift.

Below are specific examples of water purification in the installation shown.

Example 1

Natural underground water containing 1.2 mg / l Fe ²⁺ is fed into aerator 1, where it is saturated with atmospheric oxygen due to natural aeration and oxidation of Fe ²⁺ to Fe ³⁺ . Next, the water enters the filtration device, where it moves countercurrently (from bottom to top) with quartz sand of a fraction of 0.3-2 mm, which drops from top to bottom at a speed of 5 mm / min and rises with the help of an air lift to the upper part of the filter device. The purified water is disinfected with ultraviolet radiation and sent to the consumer. The ratio of the operating time of the filtering device in the filtration mode (t ₁ ) to the operating time in the mode of simultaneous filtration and washing (t ₂ ) is 2: 1. The ratio of the flows of washing water (q ₁ ) and sand (q ₂ ) in the device for washing sand is 1: 0.7. Wash water containing 20 mg / l Fe ³⁺ is sent to the separation unit 4 by filtration, separation or sedimentation, after which the liquid phase (clarified water) with a content of Fe ³⁺ 2.5 mg / l is returned to the beginning of the cleaning process, and the solid phase is removed from the process.

Other examples are given in table 1.

As can be seen from the above examples, the proposed method provides a closed cleaning mode.

The content of impurities in the water after cleaning is shown in table 2

Water meets the requirements of SanPiN 2.1.4.1074-01 “Drinking water. Hygienic requirements for the quality of centralized drinking water supply systems. Quality control. ”For drinking water.

Depending on the composition of the source water, not only air, but also other oxidizing agents, for example KMnO ₄ , O ₃ , etc. can be supplied to the oxidation stage, and in addition to inert materials, materials with selective sorption and / or ion exchange can be used as a filter charge properties.

The undoubted advantage of the claimed method is its wastelessness, while the solid phase isolated during purification is obtained in such a way that it can be used in the production of pigments.

Claims (5)

1. A method of purifying natural groundwater, including treating water with an oxidizing agent, filtering through an inert loading, washing the load, disinfecting the water with ultraviolet radiation and supplying it to the consumer, characterized in that the filtration is carried out in countercurrent mode through a movable loading layer in a filter device equipped with airlift, washing downloads are carried out in the upper part of the device simultaneously with the filtration of water, and the ratio of the operating time of the filtering device in the filtration mode (t ₁ ) to the operating time in simultaneous filtration and washing (t ₂ ) is (5-1): 1, washing water containing suspended particles is sent for separation, after which the liquid phase is returned for cleaning, and the solid phase is removed from the process. 2. The method according to claim 1, characterized in that as an inert load using quartz sand fraction 0.3-2.0 mm and provide a linear speed of its movement in the layer equal to 2-10 mm / min 3. The method according to claim 1, characterized in that the ratio of the flows of wash water (q ₁ ) and sand (q ₂ ) in the device for washing sand is q ₁ : q ₂ = (0.6-2): 1. 4. The method according to claim 1, characterized in that the separation of the wash water into solid and liquid phases is carried out by filtration, separation or sedimentation. 5. The method according to any one of the preceding paragraphs, characterized in that the solid phase removed from the process is sent to the production of pigments.