SU738638A1 - Method of cleaning water by filtering - Google Patents

Description

(54) METHOD FOR CLEANING WATER BY FILTERING

one

: The invention relates to the methods of water purification by filtration and can be used in the technology of purification of household water and after-treatment of wastewaters.5

A known method of purification of water by filtration through quartz sand, containing, wt.%: Silica 6070; mica 0.5-1; feldspar the rest is 1.10

The disadvantage of this method is the short duration of the filter cycle due to the limited porosity of the backfill and its specific surface .15

There is also known a method for purifying water by filtration through a load made of granules of expanded clay 2.

A claydite load, which has a more developed surface and has a greater porosity than quartz sand, is characterized by a higher heat capacity.

However, these properties cannot be fully utilized in the case of passing filtration of water, since, having a low density (1.6-1.8 g / cm), claydite loading is taken up at limited filtration rates. In addition, 30

effective pressure losses in the load during upward filtration, defined by the formula;

H „p hj () (i-m) where And - the marginal pressure loss in the load;

h is the thickness of the loading layer;

Load density and. water, respectively;

mj - loading porosity; for ceramsite loading 1/5 2 times lower than in loading from quartz sand.

The most concise technical solution is the method of water purification by filtration through a granular charge, containing, in wt.%: Iron oxide 3-12; silicon oxide 15-40; oxides of calcium and magnesium 15.1-90; alumina 5-15, obtained by mixing the corresponding components and calcining them at 1000 ° C, followed by grinding and sieving 3.

This method, in comparison with water purification by filtering through ceramsite loading, allows only a slight increase in the permissible speed (with upward filtering) due to a slightly higher

(5-10%) density of the filtering material compared with expanded clay.

At the same time, even with the implementation of this method, the duration of the filter cycle and the performance of the filtering facilities are limited, since the permissible limiting pressure losses in the load (before removal of contaminants from it) are close to those of filtering through ceramsite loading.

The disadvantage of this method is its high cost due to the laboriousness of manufacturing, crushing and screening the filter material.

The aim of the invention is to increase productivity by increasing the duration of the filter tank.

The goal is achieved by using nickel production slag as a load.

It is preferable that the slag of nickel production contains, wt%: iron oxide 33-35; silicon oxide 41 43; calcium oxide and magnesium 11-12; impurities rest.

An example. At the installation of the filtration-technological analogue, one of the columns with a diameter of 100 mm and a height of 3500 mm is loaded with granulated slag of nickel production (Pechengangankel combine), characterized by the following parameters, density 4.02 particle size 1.15 mm; coefficient of heterogeneity 0.96; loading layer thickness. m

At the same time, the nickel production slag contains, wt%: iron oxide 33.6; silicon oxide 42.1; calcium oxide and magnesium 11.6; nickel 0.11; impurities rest.

Slag is taken and 5 oTvalvv combine, where it comes in granular form. Slag granulation is carried out upon cooling and crystallization of the molten slag with water under a pressure of 2-4 MPa in water-cooled troughs.

Yeast water of the following composition is filtered through a column: suspended substances 4.3 mg / l; color 36 degrees; pH 7.2.

Filtration rate maintained at 7.0 m / h. Immediately before the water supply, coagulant - sulfuric acid aluminum in a dose of 6 mg / l.

The quality of the filtrate meets the requirements of GOST 28174-73 in all respects. No residual concentration of nickel in water was detected.

The benchmark for comparison is a method of purifying water by filtration through a granular load made of a material made in accordance with the prototype. The batch is made in the clay laboratory of a house-building factory by mixing and firing the components indicated in the patent.

The load contains, wt% iron oxide 10.2; silicon oxide 39, calcium oxide and magnesium 29.3; alumina 14.08; impurities rest.

The loading height and its size are identical to the test load from nickel-made slag, and the density is 1.92 g / cm.

Experimental conditions analogous to the above when testing the claimed method.

The criterion for the effectiveness of the method of water purification is the duration of the filter cycle and the amount of water cleaned after 1 filter cycle.

The results of the experiments are shown in the table.

As can be seen from the data in the table, during water purification by filtering through a granulated charge from the nickel production slag, productivity is significantly increased by increasing the duration of the filter. This is explained by better filtering properties of the charge, a lower sediment penetration rate, a more developed surface, and a high granule shape.

Experienced Production Verification

The efficiency of the method of water purification by filtering through granulated slag of nickel production was carried out at one of the contact clarifiers of the existing water body of the station in Murmansk.

The tests were carried out in the most unfavorable. flood period, when the content of suspended substances in the water of the Cola River is from 25 to 76 mg / l. At the same time, the contact illuminator loaded with granulated nickel-made slag at a filtration rate of 6.5-7 m / h has a filter cycle of 2023 h with water quality meeting the requirements of GOST 2874-73. At the same time, parallel-working contact clarifiers loaded with quartz sand have a filter cycle of 68 hours at a filtering speed of 4-4.5 m / h.

Thus, when implementing the proposed method of water purification, removal of water from a 1 m filter is increased by 2-2.5 times. .

Provided that contact clarifiers are overloaded throughout the entire station of Murmansk, the introduction of the proposed method will increase the station's performance from 140 to 280300 thousand.

The economic effect of the implementation of the proposed method minus the costs associated with overloading contact clarifiers and increasing the diameter of the throughpass pipelines,

as well as increasing the capacity of pumping stations only for the water treatment plant of the city of Murmansk, will be from 350 to 400 thousand rubles. in year. ; T

The proposed method can be implemented with single-layer and multi-layer filter loading on both existing and newly built water. Initial losses

head load, m

Loss growth rate

head cm / h

Maximum allowable head loss in loading, m

Sediment penetration rate deep into the load, m / h

Filter cycle duration, h

Cleared amount

water per filter cycle, l

Claims (3)

1. A method of purifying water by filtration through a granular charge containing iron and silicon oxides, characterized in that, in order to increase productivity by increasing the filter cycle duration, nickel slag is used as a load. 2 .. The method according to claim 1, characterized in that the nickel slag purification stations, as Pechenganickel sends about 2 thousand meters of granulated slags daily to the slag fields. Sanitary permission of the USSR Ministry of Health to use granulated slags of nickel production as a load of household water supply filters obtained. 0.3 7.2 0.92 0.121 8.5 533.8 production contains, wt.%; iron oxide 33-35; silicon oxide 41-43; calcium oxide and magnesium 11-12; impurities rest; Sources of information taken into account in the examination 1.SNiP P-31-74. 2. USSR author's certificate  267581, cl. B 01 D 39 / 02.31.07.64. 3. The patent of the USA 3827964 from 01.06.72, cl. 252, -179, publ. 08/06/74 (prototype).