SU710985A1 - Method of waste water purification from arsenic - Google Patents

Description

The invention relates to the treatment of industrial wastewater, and is also used for other types of industrial waste non-ferrous and ferrous metallurgy.

A known method of purification of industrial wastes from arsenic using electronegative metals, for example iron, when sulfur dioxide or sulfite is introduced into the solution at a molar ratio of H ^ SO. to S0 ₂ equal to Ό, 001— 'θ 2.0 [1].

There is also known a method where the solutions are purified from arsenic by ferric chloride and the arsenic-containing precipitate is separated from the solution. For this 15, the alkali content in the solution is adjusted to 7-12 g / l, after which 2-4 times the amount of ferric chloride is introduced, taking into account the arsenic content [2]. 20

The disadvantage of these methods is that they are ineffective in depth (5–20 mg / l) and uneconomical in the deposition of arsenic, and it is practically impossible to use them for treating neutral effluents.

Closest to the proposed is a method of treating wastewater from arsenic by precipitation with iron ions. Oxidation of iron is carried out by air purging. The process is carried out in the presence of S0 ₂ at an acid concentration in the solution of 3-10 g / l (pH 1.2-2.0) [3].

The disadvantage of this method is its inefficiency (it is necessary to introduce SO ^ into the solution), high operating costs, and when using the method, it is not possible to purify to MPC (maximum permissible concentration).

The purpose of the invention is to increase the degree of purification and cheaper process.

This goal is achieved by the fact that the wastewater is treated in biological ponds, where metal iron is simultaneously introduced, cultures of iron bacteria dejptothrix ochracea, deptothrix crassa, Jallionella fer — ruginea in equal proportions and additional sulfate-reducing bacteria, organic substances of carbon origin, preferably sawdust or plant residues.

The essence of the method is as follows.

When metallic iron shavings ¹ · are introduced, divalent iron ions are formed in solutions. Under the influence of iron bacteria, divalent ions 3

710985.

iron oxides are oxidized to ferric iron, which forms insoluble iron arsenates with arsenic. In order to accelerate the entry of ions into the solution and create the potential necessary for iron bacteria, $ sulfate-reducing bacteria are introduced. ,

Example, Wastewater treatment is carried out simultaneously in three versions under dynamic conditions for 6 months with continuous cultivation of microorganisms and the passage of purified solutions of arsenic.

We use models of biological ponds, which are boxes of 16 liters, 30 cm high, and 6 cm wide, made of organic glass with internal partitions for uniform flow of solutions. We use arsenic (GP) solution prepared in tap water with the original concentration of 4 mg / l and pH 7., 2-8.0,

The solution is prepared in an amount of 120 l every 10 days and served simultaneously in each model of all three options 25 on the basis of its stay in the model for 4 days.

The solution is supplied continuously throughout the day. Cleaning is carried out at room temperature 18-22 C 30 as follows:. '· Along the flow evenly place iron chips in the amount of 40 g and add organic matter in the form of hydrolyzed sawdust in the amount of? L g / l and a culture of sulfate-reducing bacteria 20 ml in the form of an inoculant, as well as' similarly 1 and b. iron, sulfate reducing bacteria, as well as a mixture of cultures of iron bacteria in a ratio of 1 are administered to the options; 1: 1, respectively, in the form of an inoculant

Sulfate-reducing bacteria are isolated from lake silt on a solid Kravtsov-Sorokin medium, iron-45 bacteria are isolated from the soil on artificial • artificial media Liske and Vol'f a-Kuch era.

In the course of the experiment, chemical analyzes are constantly performed to determine the amount of arsenic in the solutions leaving the models.

As a result, it was found that only in the third embodiment they achieve a stable reduction of arsenic by 95% (residual content on average 0.05 mg / l),

In the first and second variants, the decrease in arsenic content averages no more than 5 and 10%.

Technical and economic efficiency consists in the fact that the iron consumption is reduced by 8-10 times _f there is no need to separate sediment, the degree of purification to sanitary standards is increased, purification is carried out without deterioration of the salt composition of effluents.

To implement the proposed method does not require significant capital costs with almost complete absence of operational.

Claims (3)

The invention relates to the treatment of industrial wastewater, as well as applies to other types of industrial wastes from ferrous and nonferrous metallurgy. A method is known for cleaning industrial wastewater from arsenic using electrolyte metals, such as glands, when introduced into a solution of sulfur dioxide or sulphite at a molar ratio of 30 ,, is equal to O, 0012, 0 1. There is also known a method where the removal of solutions, from the mouse, is produced with ferric chloride and the mouse-containing precipitate is separated from the solution. For this, the alkali content in the solution is adjusted to 7-12 g / l, after which 2-4 times the amount of ferric chloride is added, considering the content of arsenic 2. The disadvantage of these methods is that they are ineffective in depth (5–20 mg / l) and uneconomical in the costs of mouse sedimentation, they are practically impossible to use for neutral wastewater treatment. The method for cleaning wastewater from mice is closest to the proposed method. by precipitating it with iron ions. Iron oxidation is carried out by air blowing. The process is conducted in the presence of SO when the acid concentration in the solution is 3-10 g / l (pH 1.2-2.0) 3. The disadvantage of the method is its uneconomical (it is necessary to introduce SO2 into the solution), high operating costs, and using the method does not ensure cleaning up to MAC (maximum allowable concentration). The purpose of the invention is to increase the degree of purification and reduce the cost of the process. The goal is achieved in that waste water is treated in biopruda, where metallic iron, depotthrix ochracea, deptothrix crassa, Jallionella ferruginea cultures in equal proportions and additionally sulphate-reducing bacteria, organic substances of carbon origin, preferably sawdust or plant residues are introduced simultaneously. The essence of the method lies in the following. Upon the introduction of metallic iron chips, ferrous ions form in solutions. Under the influence of iron bacteria, ferrous ions are oxidized to ferric ions, which form insoluble iron arsenates with the mouse. In order to accelerate the passage of ions into the solution and create the potential necessary for iron bacteria, the sulfonate recovery process is introduced. bacteria. Example. Wastewater treatment is carried out simultaneously in three variants under dynamic conditions for months with the continuous cultivation of orchids and the passage of purified arsenic solutions. Biological pond models are used, which are boxes with a volume of 16 liters, a height of 30 cm and a width of 6 cm, made of organic glass with internal partitions for a uniform flow of solutions. As a cleaned one, use a water drain (H) solution prepared using tap water. with an initial concentration of 4 mg / l and pH 7, f2--8fO, the Solution is prepared in an amount of 120 every 10 days and is served simultaneously to each model of all three options on the basis of its stay in the model for 4 days. The solution is fed continuously throughout the day. Purification of lead at room temperature 18–22 ° C as follows: along the stream, iron chips in the amount of 40 K are placed evenly in organic matter in the form of hydrolyzed sawdust in the amount of L g / l and the culture of sulfate bacteria of the hydrophobic bacteria 20 ml in the form of inoculum, , as well as similarly 1 and. the variants are given iron, sulfate, bacteria, and the C1c cultures of iron bacteria in relation 1; .1 g 1, respectively, in the form of ij} okul nta tz, 50 ml. Sulfate-reducing bacteria were isolated from lake sludge on solid Kravtsov-Sorokin medium, iron-bacteria were isolated from the soil on artificial Liske and Wolf a-Kuch'er mediums. During the experiment, constant analyzes of the amount of mice in the outgoing from models to solutions. As a result, it was found that only in the third variant, a stable reduction of the mouse by 95% (residual content on average 0.05 mg / l) is achieved. In the first and second variants, the decrease in the mouse content averages no more than 5 and 10%. . Technical and economic efficiency lies in the fact that the iron pad is reduced by 8-10 times, there is no need to separate the sediment, the degree of purification increases to sanitary standards, cleaning is carried out without degrading the salt composition of the effluent. For the implementation of the proposed method does not require significant capital expenditures with the almost complete absence of operating costs. Claims 1. A method for treating waste water from a mouse, which includes treating with an iron-containing compound to form iron arsenates, characterized in that, in order to increase the degree of purification and reduce the cost of the process, waste water is treated in biopruda, where metallic iron and cultures are simultaneously introduced ferrobacterium deptothrix ochracea, dep.totrix crassa, JalliOTiella ferruginea in equal ratios and additionally Sulfate reducing bacteria and organic matter of carbon origin. 2t. The method of populace, about t and ich ayush and with the fact that either sawdust or plant residues are used as organic substances. Sources of information taken into account in the examination 1. USSR author's certificate No. 528266, cl. C 02 C 5/02, 1971. 2. USSR Author's Certificate No. 454178, Clo C 01 G 41/00, 1975. 3. USSR author's certificate No. 559906, cl. C 02 C 5/02, 1974.