KR101844024B1

KR101844024B1 - Wastewater treatment method and composition for removing soluble COD

Info

Publication number: KR101844024B1
Application number: KR1020150130195A
Authority: KR
Inventors: 양효경; 김규리; 박현민
Original assignee: 양효경; 김규리; 박현민
Priority date: 2015-09-15
Filing date: 2015-09-15
Publication date: 2018-03-30
Also published as: KR20170032630A

Abstract

The present invention relates to a wastewater treatment method for removing soluble COD in industrial wastewater such as paper wastewater or dyeing wastewater, and a wastewater treatment composition for the same. In the present invention, a wastewater treatment agent is pre- A method of treating wastewater capable of eliminating soluble COD at an appropriate level generally required without any subsequent treatment such as Fenton oxidation by simply adding the wastewater into the coagulation bath to adjust the pH and reacting for a predetermined time, Gt; a < / RTI > waste water treatment composition.

Description

TECHNICAL FIELD The present invention relates to a wastewater treatment method for removing soluble COD and a wastewater treatment composition for the same,

The present invention relates to a wastewater treatment method for removing soluble COD in industrial wastewater such as paper wastewater or dyeing wastewater, and a wastewater treatment composition therefor.

In general, the technique of purifying wastewater has been developed in various ways, such as biological methods, chemical methods, and physical methods. Purification of wastewater is aimed at removing organic matter in water, suspended solids (SS), nutrients such as nitrogen and phosphorus, color, and microorganisms.

In particular, biodegradable soluble organic matter (NBD COD) is a particular problem in industrial wastewater such as paper mill waste and dyeing wastewater. Removal of these degradable organics is difficult only with conventional physical and biological treatment processes, so physico-chemical advanced treatment processes are added. Such physicochemical treatment processes include activated carbon adsorption, Fenton oxidation, ozone treatment, photocatalyst and UV irradiation. The most widely used method to remove soluble COD from these physicochemical treatment processes is Fenton Oxidation (Fenton Oxidation).

In the Fenton oxidation method, hydrogen peroxide (H ₂ O ₂ ) reacts with a divalent iron ion (Fe ^{+ 2} ) to generate an OH radical, which oxidizes and removes COD, which is a contaminant, by the OH radical. .

Fe ⁺ ² + H ₂ O ₂ → Fe ⁺ ³ + OH + OH ^-

OH + Fe ⁺ ² ^- > Fe ⁺ ³ + OH ^-

In the specific wastewater treatment process, the wastewater is stored in the pH adjustment and flocculation tank after the Fenton oxidation reaction. In the pH adjustment and flocculation tank, sodium hydroxide (NaOH) is injected to agitate the polymer flocculant So that coagulation can be accomplished within a short time. At this time, the iron dissolved in the wastewater is mostly precipitated by iron hydroxide and coagulated.

In the Fenton oxidation method, a large amount of hydroxide-type sludge is generated by the iron used as a reaction catalyst, and it must be treated in a separate tank, and various conditions such as the amount of the chemical should be adjusted according to the characteristics and concentration of the wastewater. There is a process difficulty that can be obtained. Reaction factors affecting the wastewater treatment efficiency in the Fenton oxidation reaction include reaction pH, hydrogen peroxide and ^bivalent iron ion (Fe ²⁺ ) injection rate, reaction time, and iron salt removal process. For example, in the Fenton's oxidation reaction, the ^bivalent iron ion (Fe ²⁺ ) acts as a catalyst and consumes the hydroxyl radicals above the proper amount. Therefore, in order for the ^bivalent iron ion (Fe ²⁺ ) to work effectively, (Fe ² ⁺ ), that is, the ratio of iron to the unsaturated hydrocarbon (Fe ² ⁺ / RH) is important. In addition, in the case of hydrogen peroxide, when the amount of hydrogen peroxide is relatively larger than that of the iron salt, the decomposition rate of hydrogen peroxide is slowed down and the reaction time becomes long. If the hydrogen peroxide remaining in the iron salt removing step is decomposed, Can float up and become a factor that hinders sedimentation. On the contrary, when the amount of iron salt is relatively higher than that of hydrogen peroxide, the reaction is adversely affected and the disadvantage of the fenton oxidation is increased and the treatment is obstructed. That is, if the amount of hydrogen peroxide is increased and the amount of ^bivalent iron ions (Fe ²⁺ ) is increased, the treatment efficiency increases to a certain limit. However, if the amount of hydrogen peroxide is large, If the injected amount of (Fe ²⁺⁾ is increased many a treatment cost of sludge produced by the iron salt, in consideration of the reaction time, reaction rate, the remaining amount of hydrogen peroxide, such as hydrogen peroxide and total treatment costs are two iron ions (Fe ²⁺ ) Should be determined.

As described above, the Fenton oxidation method has a problem that the wastewater must be sent to a separate water tank for oxidation, and the various conditions must be adjusted optimally and the amount of the chemicals must be appropriately adjusted. In addition, the iron sulfate (FeSO ₄ ) used in the Fenton reaction has an excessive amount of hydrogen peroxide because it inhibits the Fenton reaction due to the high concentration of sulfate ions, thereby deteriorating the COD reduction effect. Therefore, there is a problem.

To improve this Fenton oxidation, the Republic of Korea Patent Publication No. 2001-0088752, which arc the waste water used in place of the ferrous sulfate (FeSO _4), ferrous chloride (FeCl ₂₎ Fenton reagent with Fe perchlorate {Fe (ClO ₄₎ _2} Processing method. Korean Patent Registration No. 10-0434392 discloses a process for producing perchlorate which can obtain a high COD removal rate while using less amount of hydrogen peroxide than the amount used in the conventional Fenton oxidation reaction by adding perchlorate as a catalyst during the Fenton oxidation reaction And a method of treating wastewater. However, these remedies have not been able to significantly improve the problems of the Fenton oxidation method or to provide a high-level COD removal method that can replace the Fenton oxidation method due to local improvement measures that reduce the problems caused by the sulfate ion and the drug use during the Fenton reaction have.

Korean Patent Publication No. 2001-0088752 Korean Patent Publication No. 10-0434392 Korean Patent Publication No. 10-0565731 Korean Patent Publication No. 10-0434676

The present invention relates to a wastewater treatment method capable of effectively removing soluble COD in plant wastewater such as paper wastewater or dyeing wastewater by simply treating the coagulation tank in a conventional wastewater treatment facility without requiring a separate treatment tank, And a wastewater treatment composition for the same.

Particularly, in the present invention, even if an adsorbent or a coagulant is used in the existing wastewater treatment process, the degree of soluble COD removal is not sufficient and the wastewater treatment agent must be uniformly pretreated and prepared It is possible to remove solubility COD at an appropriate level generally required without further processing such as Fenton oxidation by adjusting the pH and reacting for a predetermined time by adding it into the flocculation tank by greatly increasing the removal rate of soluble COD from the wastewater treatment agent And a wastewater treatment composition for the same.

In order to achieve the above object, in the present invention,

A composition step of a wastewater treatment composition for uniformly pretreating and constituting wastewater treatment chemicals; A step of adding the wastewater treatment composition obtained in the above step to a flocculation tank at a concentration of 100 to 1000 ppm and adjusting the pH to 5 to 8 and then reacting for 15 to 30 minutes to remove soluble COD in the wastewater,

The step of forming the wastewater treatment composition comprises:

Adding 3 to 5 ml of 1.5 to 2.5% by weight aqueous sodium chloride solution and 0.5 to 1.5 g of aluminum sulfate powder to 1 liter of a ferrous chloride solution (38% by weight), heating the mixture at a temperature of 30 to 70 캜 for 2 hours or more;

Cooling the heated solution and allowing it to stand for 1.5 to 3 hours;

0.5 to 1.5 g of iron oxide powder containing 70 wt% or more of ferrous oxide and 0.2 to 0.8 g of elvan powder having 3 to 150 thousand pores per 1 cm 3 were mixed in the left solution, Lt; / RTI > for 11-13 hours;

Mixing 0.5-1.5 g of diatomite powder with the solution and allowing to stand for 0.5-2 hours; And

And mixing 0.5 to 1.5 g of powdered activated carbon into the leftover solution.

In the step of removing soluble COD, it is preferable that the wastewater treatment composition is added to the flocculation tank at a concentration of 300 to 800 ppm. The pH is preferably adjusted to 6 to 7.

The wastewater includes industrial wastewater, especially paper wastewater or dyeing wastewater.

It is preferable that the sodium chloride aqueous solution and the aluminum sulfate powder are prepared by first dissolving aluminum sulfate powder in an aqueous solution of sodium chloride and then adding the solution to the ferrous chloride solution.

The aluminum sulfate powder preferably contains 0.8 to 1.2 g per liter of ferrous chloride solution (38% by weight).

The iron oxide powder preferably contains 80 wt% or more of ferric oxide and 0.8 to 1.2 g of the iron oxide powder.

The granite powder is preferably mixed with 0.4 to 0.6 g and a particle size of 10 to 1000 탆.

The daily light powder is preferably mixed with 0.8 to 1.2 g and a particle size of 10 to 1000 탆.

Further, in the present invention,

Cooling the heated solution and allowing it to stand for 1.5 to 3 hours;

And mixing 0.5 to 1.5 g of powdered activated carbon into the leftover solution. The present invention also provides a method for producing a wastewater treatment composition for removing soluble COD.

Further, in the present invention,

[0050]

3 to 5 ml of 1.5 to 2.5% by weight aqueous sodium chloride solution per 1 liter of ferrous chloride solution (38% by weight); 0.5 to 1.5 g of aluminum sulfate powder; 0.5 to 1.5 g of iron oxide powder containing not less than 70% by weight of ferrous oxide; 0.2 to 0.8 g of elvan powder having 3 to 150 thousand pores per cm 3; 0.5 to 1.5 g of a light powder; And 0.5 to 1.5 g of powdered activated carbon. The present invention also provides a wastewater treatment composition for soluble COD removal.

The description of each of the constitution in the method for producing the wastewater treating composition and the constitution in the wastewater treating composition is the same as the above-mentioned wastewater treatment method.

The present invention effectively removes the soluble COD in industrial wastewater such as paper wastewater or dyeing wastewater without any additional process by injecting the wastewater treatment composition prepared by uniformly pre-treating wastewater treatment chemicals into the coagulation tank of existing wastewater treatment facility can do. The present invention relates to a process for removing soluble COD in industrial wastewater, which requires a separate treatment tank for treating the wastewater, and adjusting conditions according to the characteristics and concentration of wastewater. Soluble COD in industrial wastewater such as dyeing wastewater, paper wastewater and the like can be simply and effectively removed, so that it can be widely used instead of the Fenton oxidation method.

FIG. 1 is a photograph showing a comparison between treated water treated with the wastewater treatment composition of the present invention and raw wastewater.
2 is a photograph of various paper wastewater treated with the wastewater treatment composition of the present invention.

A wastewater treatment method of the present invention comprises: a wastewater treatment composition composition step of uniformly pretreating and constituting wastewater treatment chemicals; And a step of injecting the wastewater treating agent composition obtained in the above step into an agglomeration tank to remove soluble COD in the wastewater. Each process will be described in detail below.

The composition of wastewater treatment composition

The waste water treating composition of the present invention is obtained by a method including the following steps.

(a) 3-5 ml of a 1.5-2.5% by weight aqueous solution of sodium chloride and 0.5-1.5 g of aluminum sulfate powder are added to 1 l of ferrous chloride solution (38% by weight), heated at 30 to 70 캜 for 2 hours or longer step;

(b) cooling the heated solution and allowing it to stand for 1.5 to 3 hours;

(c) mixing 0.5 to 1.5 g of the iron oxide powder and 0.2 to 0.8 g of the elvan powder to the leftover solution and heating the mixture at 30 to 35 ° C for 11 to 13 hours;

(d) mixing 0.5-1.5 g of anilite powder in the solution and allowing to stand for 0.5-2 hours; And

(e) mixing 0.5 to 1.5 g of powdered activated carbon into the leftover solution.

Ferrous chloride is a compound of chlorine and iron, which is a white or pale green, deliquescent crystal, and ferrous chloride has been used as a coagulant in conventional wastewater treatment. In the present invention, an industrially produced ferrous chloride solution (38% by weight) is used. The 'ferrous chloride solution' in the present invention means a ferrous chloride solution of 38 wt%.

Also known as the sulfate, aluminum sulfate, alumina, the general formula is Al ₂ (SO ₄₎ _3. Conventionally used as mordants, foam extinguishers, medicines, coagulants in wastewater treatment. The injection rate when used as a coagulant in wastewater treatment is generally in the range of 10 to 100 ppm, and the optimum pH of coagulation reaction is known to be 6.0 to 7.0. The dissociated aluminum ions may react with other ions in the composition as they are to form a salt, thereby promoting the adsorption action of other components or directly adsorbing the aluminum ions. In the present invention, the dissociated aluminum ions form salts with other ions to promote the adsorption action of the composition directly by promoting the adsorption action and the adsorption action of the other components.

In the step of adding the sodium chloride aqueous solution and the aluminum sulfate powder to the ferrous chloride solution, it is preferable that the aluminum sulfate powder is first dissolved in the sodium chloride aqueous solution and then the solution is added to the ferrous chloride solution. This input sequence is important because it affects the reaction of the dissociated ions and the resulting salts.

Iron oxide is a compound of iron and oxygen, and includes ferrous oxide, ferric oxide, and iron tetroxide. The iron oxide powder preferably contains at least 70% by weight of ferrous oxide, more preferably at least 80% by weight of the ferrous oxide. In the present invention, the iron oxide reacts with other components in the composition or accelerates the reaction of other components, thereby increasing the persistence and efficiency of the coagulation reaction.

The elvan granite powder is obtained by uniformly pulverizing the elvan stone, and preferably has a particle size of about 10 to 1000 탆. The elvan granite is a mixture of quartz and feldspar, and its main components are anhydrous silicic acid and aluminum oxide. It contains a small amount of 2 iron oxides and contains about 25,000 inorganic salts. The elvan powder preferably contains 3 to 150,000 pores per cm 3, and is very strong in adsorption. It can adsorb organic substances in wastewater, and can also remove harmful metals through an ion exchange function.

The chemical composition is (K, H ₃ O) Al ₂ (Si, Al) ₄ O ₁₀ (H ₂ O, OH) _{2, which} is a mica-type mineral belonging to monoclinic. In the present invention, the daily light powder preferably has a particle size of about 10 to 1000 mu m. In the present invention, ilite can remove ionic substances dissolved in wastewater by ion exchange.

Powdered activated carbon is the most widely used material as an adsorbent. It can adsorb both organic and inorganic substances and adsorbs and removes odorous substances in pollutants. Activated carbon Carbonization and Activation During the manufacturing process, pore size is increased by doubling the adsorption capacity by the molecular size, and the internal area of the pore is more than 1000 m2 per 1 g of activated carbon.

In the present invention, each of the above-mentioned composition components is not simply mixed, but is optimized to remove soluble COD in the wastewater through mutual reaction and stabilization process through mixing order, The resulting final composition can remove soluble COD in the wastewater with high efficiency through adsorption, flocculation, and ion exchange action when an appropriate amount is added to the wastewater.

Soluble COD removal process

The wastewater treatment composition of the present invention obtained through the above composition step is added to the flocculation tank at a concentration of 100 to 1000 ppm, the pH is adjusted to 5 to 8, and the soluble COD in the wastewater is removed by reacting for 15 to 30 minutes. The COD of stained wastewater or paper wastewater having a high contamination level can be removed to a generally acceptable level only by the input treatment of the wastewater treatment composition.

The wastewater treatment composition is preferably put into the flocculation tank at a concentration of 300 to 800 ppm. In addition, the pH is preferably adjusted to 6 to 7.

Hereinafter, the present invention will be described in more detail with reference to examples. The following examples illustrate the invention and are not to be construed as limiting the scope of the invention.

&Lt; Example 1 >

Preparation of raw materials

The raw materials were prepared as follows.

1. ferrous chloride _{(FeCl 2 -FeCl 2 .4H 2 O} ) solution (38% weight)

2. Aluminum sulfate powder (Al ₂ (SO ₄ ) ₃ )

3. Carbon activated powder 8 * 30

4. Illite powder {K _0.75 [Al _1.75 (MgFe ²⁺ ) _0.25 ] (Si _3.50 Al _0.50 ) O ₁₀ (OH) ₂ }

5. Epsom powder

6. Iron oxide powder

7. Industrial salt

Preparation of composition

(1) In order to prepare an aqueous solution of 2% by weight sodium chloride, 20 g of salt was added to 1 liter of common distilled water and dissolved well.

(2) 1 g of aluminum sulfate powder was dissolved in the sodium chloride aqueous solution.

(3) The above solution was added to 1000 ml of a ferrous chloride solution (38% by weight), and the mixture was heated at a temperature of 30 to 70 캜 for 2 hours or more with stirring.

(4) After heating, the solution was allowed to cool and the cooled solution was allowed to stand for 2 hours.

(5) 1 g of the iron oxide powder and 0.5 g of the elvan flake were added to the thus-left solution, and the mixture was stirred and heated at 30 to 35 ° C for 12 hours.

(6) 1 g of Illium powder was added to the solution, stirred, and left for 1 hour.

(7) 1 g of powdery activated carbon was added to the thus-left solution and stirred to complete the wastewater treatment composition of the present invention.

&Lt; Example 2 >

The waste water treatment composition of Example 1 was used to treat wastewater as follows.

0.5 ml of the composition of Example 1 was added to 1000 ml of wastewater, the pH was adjusted to about 6, and then the mixture was treated for 0.5 hour. The salinity, COD and pH of untreated raw water and treated water were compared and the results are shown in Table 1 and FIG.

As can be seen from the results of Table 1, the treated water treated with the wastewater treatment composition of the present invention had significantly lower COD than the untreated wastewater. In addition, as can be seen from the photograph of FIG. 1, the treated water (right side) was clarified similar to that of general water, compared to the raw water of high color and high turbidity (left).

&Lt; Example 3 >

One kind of dyeing wastewater and three kinds of paper wastewater (three paper making: represented by A, B and C) were treated as follows by using the wastewater treatment composition of Example 1 above.

0.5 ml of the composition of Example 1 was added to 1000 ml of each wastewater and the mixture was treated for 0.5 hour. The COD before and after treatment was compared and the results are shown in Table 2 below. A photograph of the process is shown in FIG.

As can be seen from the results in Table 2, the COD value after treatment with the wastewater treatment composition of the present invention was significantly lower than that before treatment. Also, the change of COD value was remarkable especially in the dyeing wastewater where the COD value before treatment was very high.

Claims

A composition step of a wastewater treatment composition for uniformly pretreating and constituting wastewater treatment chemicals; A step of adding the wastewater treatment composition obtained in the above step to a flocculation tank at a concentration of 100 to 1000 ppm and adjusting the pH to 5 to 8 and then reacting for 15 to 30 minutes to remove soluble COD in the wastewater,
The step of forming the wastewater treatment composition comprises:
3 to 5 ml of 1.5 to 2.5% by weight sodium chloride aqueous solution and 0.8 to 1.2 g of aluminum sulfate powder are added to 1 liter of a ferrous chloride solution (38% by weight), and the mixture is heated at a temperature of 30 to 70 캜 for 2 hours or more;
Cooling the heated solution and allowing it to stand for 1.5 to 3 hours;
0.5 to 1.5 g of iron oxide powder containing 70 wt% or more of ferrous oxide and 0.2 to 0.8 g of elvan powder having 3 to 150 thousand pores per 1 cm 3 were mixed in the left solution, Lt; / RTI > for 11-13 hours;
Mixing 0.5-1.5 g of diatomite powder with the solution and allowing to stand for 0.5-2 hours; And
Mixing 0.5 to 1.5 g of powdered activated carbon into the leftover solution,
Wherein the wastewater is industrial wastewater containing paper wastewater or dyeing wastewater.

The method according to claim 1,
Wherein the step of removing the soluble COD comprises charging the wastewater treatment composition at a concentration of 300 to 800 ppm in the flocculation tank.

The method according to claim 1,
Wherein the step of removing the soluble COD regulates the pH to 6 to 7.

delete

The method according to claim 1,
Wherein the sodium chloride aqueous solution and the aluminum sulfate powder are prepared by first dissolving aluminum sulfate powder in an aqueous solution of sodium chloride and then adding the solution to the ferrous chloride solution.

delete

The method according to claim 1,
Wherein the iron oxide powder contains at least 80 wt% of ferrous oxide and is mixed with 0.8 to 1.2 g.

The method according to claim 1,
Wherein the granite powder is mixed with 0.4 to 0.6 g and has a particle size of 10 to 1000 탆.

The method according to claim 1,
Wherein 0.8 to 1.2 g of the diatomite powder is mixed and the particle size is 10 to 1000 占 퐉.

3 to 5 ml of 1.5 to 2.5% by weight sodium chloride aqueous solution and 0.8 to 1.2 g of aluminum sulfate powder are added to 1 liter of a ferrous chloride solution (38% by weight), and the mixture is heated at a temperature of 30 to 70 캜 for 2 hours or more;
Cooling the heated solution and allowing it to stand for 1.5 to 3 hours;
0.5 to 1.5 g of iron oxide powder containing 70 wt% or more of ferrous oxide and 0.2 to 0.8 g of elvan powder having 3 to 150 thousand pores per 1 cm 3 were mixed in the left solution, Lt; / RTI > for 11-13 hours;
Mixing 0.5-1.5 g of diatomite powder with the solution and allowing to stand for 0.5-2 hours; And
And mixing 0.5 to 1.5 g of powdered activated carbon into the leftover solution. 2. The method according to claim 1, wherein the organic wastewater is a mixture of water and an organic solvent.

11. The method according to claim 10, wherein the sodium chloride aqueous solution and the aluminum sulfate powder are prepared by first dissolving aluminum sulfate powder in an aqueous solution of sodium chloride and then adding the solution to the ferrous chloride solution.

delete

11. The method according to claim 10, wherein the iron oxide powder contains at least 80 wt% of ferrous oxide and 0.8 to 1.2 g of the iron oxide powder.

11. The method of claim 10,
Wherein the elvan powder is mixed with 0.4 to 0.6 g and the particle size is 10 to 1000 占 퐉.

11. The method according to claim 10, wherein 0.8 to 1.2 g of the diatomite powder is mixed and the particle size is 10 to 1000 m.

10. A process for the preparation of a compound of formula < RTI ID =
3 to 5 ml of 1.5 to 2.5% by weight aqueous sodium chloride solution per 1 liter of ferrous chloride solution (38% by weight); 0.8 to 1.2 g of aluminum sulfate powder; 0.5 to 1.5 g of iron oxide powder containing not less than 70% by weight of ferrous oxide; 0.2 to 0.8 g of elvan powder having 3 to 150 thousand pores per cm 3; 0.5 to 1.5 g of a light powder; And 0.5 to 1.5 g of powdered activated carbon. 2. A wastewater treatment composition for removing soluble COD in industrial wastewater comprising paper wastewater or dyeing wastewater.

17. The composition of claim 16, wherein the composition comprises 0.8 to 1.2 g of iron oxide containing at least 80% by weight of ferric oxide; 0.4 to 0.6 g of an elvan powder having a particle size of 10 to 1000 탆, and 0.8 to 1.2 g of a diatomite powder having a particle size of 10 to 1000 탆.