SU1330077A1 - Method of defluorination of natural water - Google Patents

Abstract

The invention relates to water treatment methods and can be used in the defluorization of natural waters. The method allows to reduce the consumption of aluminum-containing coagulant, increase the degree of defluorization and simplify the cleaning process. To carry out the process, water is treated with a suspension of bentonite clay in a solution of aluminum-containing coagulant with a pH of 3.0-3.2 at a mass ratio of Alj Oz and bentonite clay 1: (5-7). The suspension is prepared by intensive mixing of the clay in the coagulant solution for 20-40 minutes. After the reagent is injected and stirred, the water is clarified by settling and filtered. In comparison with the known method, the proposed method allows reducing the dose of aluminum salts by 25-30% and increasing the degree of purification. 1 hp f-ly. 1 tab. with so

Description

The invention relates to water treatment methods and can be used in the defluorization of natural waters.

The purpose of the invention is to reduce the consumption of aluminum-containing coagulant, increase the degree of defluorization and simplify the process.

The water treatment is carried out with a suspension of bentonite clay prepared in a solution of aluminum-containing coagulant with a pH of 3.05-3.20. The mass ratio of aluminum-containing coagulant (according to AUOj) and bentonite clay takes mostly 1: (5-7) with a contact time of 20 + 40 minutes.

Mixing clay in a solution of aluminum-containing coagulant with a pH of more than 3.2 with a contact time of less than 20 minutes leads to a decrease in the defluorization effect, since at a pH of more than 3.2, the leaching of aluminum ions from the clay is slow. A decrease in the pH of the coagulum solution to less than 3.05 and an increase in the contact time of more than 40 minutes is impractical, since this does not cause a significant change in the degree of water detoration. The decrease in the de-fluorination effect while reducing the clay consumption less than 1: 5.0 is due to a smaller amount of aluminum ions passing into the solution and an insufficient number of centers.

Sequential introduction to water: coagulant

45 60 60 90 .45

150 200 100 150 315

6 7

Sequence in water: bentonite-coagulant nt

45 150 1: 3,3575 6,41,87

45, 315 1: 7,075 6,41,76

60,200 1: 3,35,100 6,41,46

0

coagulation. An increase in clay consumption over 1: 7.0 leads to an increase in the cost of cleaning and complication of the operation of the reagent agent without changing the quality of the treated water. Contact of aluminum-containing coagulant and bentonite clay is carried out in coagulant solution tanks, which allows refusing additional solution and feed tanks for the clay slurry.

A solution of an aluminum-containing coagulant with a pH of 3.05-3.20 is prepared as follows. Load clay in an amount that provides the ratio of aluminum salts and clay 1: (5.0-7.0). The solution is intensively stirred for 20-40 minutes. The resulting clay suspension is pumped into supply tanks and dispensed in the treated water. The dose of the reagent is chosen based on the quality of the source water. After the resulting suspension of bentonite clay is introduced, the water is clarified by settling and filtered.

Example 1. The original water with a fluorine content of 6.4 mg / l is treated according to the known and proposed method. After treatment, the content of fluoride ions in water is determined.

The results obtained are presented in the table.

1.8

1.45

1.60

1.20

1.72

9 10

60 90

100 150

Water treatment with a suspension of bentonite clay, mixed in a concentrated solution of coagulant

11 12 13 14 15 16 17

45 45 45 45 30 30

150 225 315 360 210 240

1: 3.35

1: 5.0

1: 7.0

1: 8.0

1: 7.0

1: 8.0

75 75 75 75 50 50

6.4 6.4 6.4 6.4

6.4 6.4

1.48 1.20 0.90 0.91 1.50

1.50 1.48

the experience is similar to experience 13, but the resulting reagent solution is filtered through a dense paper filter

Example 2. The original water with a fluorine content of 5.8 mg / l is treated with a suspension of clay prepared in concentrated solutions of aluminum sulphate with a pH of 3.55; 3.35; 3.22; 3.1; 3.05 and 3.0. The dose of aluminum sulfate administered as AUO was 30 mg / l. The ratio of aluminum sulphate (according to AUOs). and bentonite length 1: 6.0. After settling and filtering in water, respectively, 2.10; 1.75; 1.32; 1.24; 1.22 and 1.22 mg / l of fluorine.

As can be seen from the above examples, the proposed method for defluorization of natural waters in comparison with the known one allows for a reduction in the dose of aluminum salts to be administered.

Reducing the consumption of aluminum-containing coagulant and avoiding additional supply tanks and devices for

Editor M. Nedoluzhenko Order 3533/23

Compiled by L; Ananyeva Tehred I. VeresKorrektor L. Patay

Circulation 850 Subscription

VNIIPI USSR State Committee for Inventions and Discoveries

1 13035, Moscow, Zh-35, Raushsk nab. 4/5 Production and printing company, Uzhgorod, ul. Project, 4

Continued t jblitsy

100 150

6.4 6.4

1.72 1.23

75 75 75 75 50 50

6.4 6.4 6.4 6.4

6.4 6.4

1.48 1.20 0.90 0.91 1.50

1.50 1.48

mixing and dosing of the clay slurry makes it possible to simplify the process of defluorization of natural waters.

Claims (2)

Claims. Method of defluorinating natural water, including the treatment of aluminoaccharide with a coagulant and a suspension of bentonite clay, followed by sedimentation and filtration, characterized in that In order to reduce the consumption of coagulant, increase the degree of defluorization and simplify the process, the treatment is carried out with a suspension of bentonite clay in a solution of aluminum-containing coagulant with a pH of 3.0-3.2. 2. The method according to claim 1, wherein that aluminum-containing coagulant and bentonite clay are used at a mass ratio of 1: (5-7).