SU722848A1 - Method of underground water purification from iron - Google Patents

Description

The invention relates to the purification of earth waters.

The known method of purification of groundwater from iron, which is carried out by introducing oxygen or oxygen releasing substance into the aquiferous groundwater layer and filtering 1.

Additional wells are needed to implement this method, which is associated with an increase in capital costs. This method does not give a degree of purification at a pH of 4 6.8.

Closest to the proposed invention is a groundwater purification method, in which substances containing or evolving oxygen 2 are introduced into the satellite well to the source in the direction of the outflow of the underground water.

This method is more economical, but does not provide a sufficient degree of purification at low pH values,

The purpose of the invention is to increase the purity.

This is achieved by saturating the aquiferous soil layer with an air-ammonia mixture.

The essence of the process is as follows.

In the well equipped with a filter and. submerged pump, put the pipe connected to the compressor for supplying air-ammonia mixture. The filter is separated from the rest of the hour. These wells are horizontal septum.

0

At the beginning of the cycle, the compressor is turned on and the air-ammonia mixture is fed into the water pumping layer. The charger lasts for 3060 .min.

five

The introduction of the air-ammonia mixture directly into the aquatic layer of the soil contributes to its fuller. saturation with oxygen and ammonia, which in turn contributes to a more rapid oxidation of iron.

As a result of the adsorption of dissolved oxygen and ammonia on the surface of waterborne rock grains and their presence in the pore spaces, favorable conditions are created for increasing the pH and the redox potential of the medium, binding part of the free carbon dioxide.

thereby contributing to the oxidation of iron (II).

After charging, there is a period of contact of the oxidizing agents with water and with iron dissolved in it for 0.5-1 hours, after which the working cycle, i.e. the removal of iron-free water from the well by a pump, the filter cycle is considered until the breakthrough of iron in water is higher than HOpivEJ.

After depletion of oxygen and ammonia in the bottomhole zone, the charge is recharged by injecting an air-ammonia mixture,

The proposed method differs from the well-known in that in this case the air-ammonia mixture under pressure is injected into the water-bearing soil layer, which leads to an expansion of the field of application (the method of deironing all types of groundwater is suitable), to reduce construction costs, since the need for oxidation wells, to reduce the charging time and increase the filtration cycle.

Example 1. Water with a total iron content of 6.8 mg / l, with a pH of 6.0, is subjected to deferrization under natural conditions by injecting an air-1 m mixture under pressure P 40 m. Air injection time is 1 h. During this time, served 10 m | of air. Considering that the mass of 1 m of air is 1.293 kg, and by mass. in the air, oxygen occupies 23.2%; it turns out that 301 g of oxygen is introduced from 1 m of air.

After the air-ammonia mixture is injected (ammonia is metered out to 15 g per 1 m of air), the well is shut off for 0.5-1 hours to dissolve and contact the gases with water. In the filtrate iron corresponds.

By the known method 2 required, the degree of purification from iron was not achieved due to the low pH,

The duration of the filter cycle is 56-60 hours.

Example 2. Natural water with a total iron content of 8.8, pH 5.8 with an oxidation capacity of 12.8 mg, alkalinity of 1.56 mg-eq / l is deironed under natural conditions by introducing an air-ammonia mixture under pressure of 3.2 At air injection time of 45 minutes, the amount of ammonia is 15% of the amount of injected oxygen. After 0.5 h after the end of the supply of the air-ammonia mixture, water is pumped out in an amount corresponding to the filtration coefficient. There is no iron in the filtrate.

Duration of the filter cycle is 52-54 hours.

The use of the proposed method makes it possible to reduce capital costs by at least 50% with an increase in the degree of purification from iron. The proposed method can be applied to waters with a low pH value. In general, the deferrization effect according to the invention is obtained by 6065% higher compared with the prototype, and the charging time is almost two times less (taking into account the contact).

Claims (2)

1. US Patent No. 3649533, cl. C 02 B 1/28, 1972. 2. For France 2325606, cl. C 02 V 1/26, 1977 (prototype).