KR860000097B1 - The method for treatment of waste water - Google Patents

Abstract

This method is a treatment process for the hazardous objects generated in the manufacturing of coke. A filter material contains an activated carbon, 75-85%, a powder coke, 8-12%, and an anthracite, 8- 12%. The before and after treatment filters(1), (9) contain a filter material. A chloride of iron with 130-160 mg/1 concentration is added to remove cyanogen. The addition of caustic soda makes a hydrogen ion concentration with a pH of 6-7. The before treatment filter(1) removes oil powders, floating substances, cyanide and phenol. Also, it lowers the COD.

Description

Pollution Treatment Method of Coal Gas Liquid

Figure is a process chart of the present invention.

The present invention relates to a method for treating pollutants of coal gas liquid generated during coke production. Wastewater of coal gas liquid contains cyanide, ammonia, oil and other pollutants. Therefore, the pollutants are purged by removing pollutants before discharge. Due to the low purification efficiency, cyanide, oil, chemical oxygen demand (hereinafter referred to as COD) in the discharged water exceeded the regulations of the Pollution Prevention Act, and there were frequent problems of equipment accidents.

Generally, coal tar is prepared by separating the liquefied liquid from coal gas liquid, and the gas liquid wastewater purified from ammonia is removed from the filter to remove oil and suspended solids, and the nutrients of gaseous wastewater and bacteria (Bacteria) collected in the mixing tank are collected. Phosphoric Acid (Phosphoric Acide) is mixed and biochemical treatment by transfer bacteria in the aeration tank is decomposed pollutants. The sludge generated at this time is precipitated in the primary settling tank and transferred to the reaction tank. At this time, in order to remove the cyanide component, ferric chloride is fed and then transferred to a reducing tank to precipitate and settle quicklime (CaO), and then introduced into a coagulation tank to introduce a polymer coagulant (Polymer) to promote the coagulation reaction.

After the flocculation reaction is completed, precipitate in sedimentation tank to separate sedimentation sludge and wastewater, discharge wastewater, collect sedimentation sludge in a concentration tank, and after a certain amount, add ferric chloride and calcium hydroxide in the sludge mixing tank to separate sludge and water. Although sludge lumps are incinerated after dehydration to the dehydrator, the purification efficiency of the lump coke, which is a filter agent, is low, resulting in the problems described above.

The present invention is an invention that solves the above problems and will be described with reference to the drawings and embodiments as follows. In order to facilitate the understanding of the present invention, the gas-liquid wastewater from which coal tart and ammonia are extracted from the coal gas liquor generated during the coke production process is treated with cyanide and phenol (Phenol) as well as oil and suspended solids in the pretreatment filter (1). ) And lower the COD.

At this time, the filter agent is used instead of conventional lump coke, activated carbon: 75-85%, powdered coke: 8-12%, anthracite: 8-12%, a mixture of cyanide, phenol, etc. are removed together. The filtered gaseous wastewater is collected in the mixing tank 2, and then mixed with the phosphoric acid 14 while being transported to the aeration tank 3, and the air is injected into the aeration tank 3 to perform biochemical treatment by bacteria. Decompose the remaining pollutants. The sludge generated at this time is precipitated in the settling tank (4), flowed into the cyan removal tank (5), the ferric chloride (15) is added to remove the cyan. The cyan-free wastewater is transferred to a pH adjusting tank 6, and caustic soda (NaOH) is added to adjust the acidity of the wastewater to weak acid or neutral (pH 6-7).

In this way, the neutralized wastewater is introduced into the coagulation tank 7, the polymer coagulant 7 is introduced, the coagulation reaction is promoted, and when the reaction is completed, the precipitate is transferred to the coagulation sedimentation tank 8 and settled in the post-treatment filter 9. After the second filtration, the wastewater is discharged, and the sedimentation sludge is collected in the concentration tank 10. When a certain amount is collected in the concentration tank (10), it is transferred to the sludge mixing tank (11), a coagulant of ferric chloride (15) and calcium hydroxide (18) is added to separate the moisture of the sludge, and then completely dehydrated in the dehydrator (12). The mass is incinerated in the incinerator 13.

The filter agent used in the present invention contains activated carbon, which is effective in removing suspended solids and phenols, and when it is less than 75%, the removal efficiency of suspended solids and phenol is worsened, and when it exceeds 85%, the filtration treatment time becomes longer. As the workability becomes poor, the ratio of activated carbon is 75-85%, and anthracite coal which is effective in removing oil and cyanide and powder coke which is effective in lowering COD are adjusted and added in the range of 8-12%, respectively. .

On the other hand, outside of pH 6-7, the additive ferric chloride reacts with cyanide compounds in the wastewater and redissolves in the wastewater. In addition, pH adjustment requires a large amount of quicklime and the reaction time is long, so the pH adjuster uses caustic soda.

Compared with the conventional method of the present invention as described above, the reduction of the use agent and the purification efficiency are remarkably improved.

Example 1

In the process to which the present invention described above is applied, the coal gas liquor wastewater is pretreated by using the filter medium of the present invention, which is mixed with the conventional filter made of goose coke and 80% of activated carbon, 10% of anthracite coal, and 10% of flakes. The results of filtration once in) are shown in Table 1, which is divided into Comparative Examples and the present invention. By using the filter of the present invention, it can be seen that the removal efficiency of the pollutant is significantly increased and the COD is reduced.

TABLE 1

Example 2

Table 2 shows the results of measuring the cyan content and the consumption of 10% caustic soda after pH adjustment according to the ferric chloride addition amount after pH adjustment using the filtered gas liquid wastewater in Example 2 as samples. At this time, 10% caustic soda consumption was expressed as the concentration in the gas liquid wastewater.

TABLE 2

표 2에서 가스액 폐수중의 시안함량을 임의의 값이하로 하는데 필요한 염화제2철의 량이 본 발명이 비교예에 비하여 적게 됨을 알 수 있는데, 일예로 가스액 폐수중의 시안함량을 1.10mg/l로 하는데 있어서 염화제2철의 필요농도는 비교예의 경우 484mg/l임에 비추어 본 발명은 302ng/l에 불과함을 알 수 있다.

In Table 2, it can be seen that the present invention reduces the amount of ferric chloride required to make the cyanide content in the gaseous wastewater less than an arbitrary value. In view of the necessary concentration of ferric chloride in the comparative example is 484mg / l it can be seen that the present invention is only 302ng / l.

On the other hand, according to the present invention by reducing the addition amount of ferric chloride it is also possible to reduce the addition amount of caustic soda necessary for pH adjustment.

Example 3

Table 3 shows the analysis value of the gaseous wastewater which passed through the post-treatment filter 9, and in the case of the present invention, all the subjects of regulation are below the limit value of the pollution law, but in the comparative example, only phenol is below the limit value. .

On the other hand, it was found that the amount of ferric chloride required to lower the cyanide concentration in the treated wastewater to 1.0 mg / l or less was 130-160 mg / l, but if it exceeds 160 mg / l, There is little increase in cyan removal rate.

TABLE 3

In summary, the filter agent of the present invention has a very high adsorption rate as compared with the conventional filter agent, and is characterized by being irreversible, selectively adsorbing, and having a fast adsorption rate when adsorbing pollutants.

In addition, since caustic soda is not added without quick lime, acidity can be easily adjusted, and the amount of sediment generated is reduced, thus preventing equipment accidents.

The main feature of the present invention is that the filter agent of the present invention is used in the filter (1) and (9), and the pretreatment filter is performed using the pretreatment filter (1) and the post-treatment filter (9). In addition to removing it in advance, it also removes free cyanide and cyanide salts. In addition, since the post-treatment results require the remaining pollutants to be reused, it is a great invention to protect the marine resources by preventing the marine pollution as well as the texture of the treatment agent.

Claims (1)

Pre-treatment filter (1) (9) consisting of filter material mixed in the mixing ratio of activated carbon 75-85%, coke 8-12%, anthracite 8-12% in removing pollutants from coal gas liquor wastewater. A method for treating pollutants in coal gas liquids, wherein ferric chloride is added at a concentration of 130-160 mg / l as a cyanide removing agent and caustic soda is added to have a hydrogen ion concentration of 6-7.

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