KR20170014568A - Methods for electronic wastewater treatment at an ultra-low concentration of contaminants adapting microfiltration membrane bioreactor process and selective heavy metal removal process - Google Patents

Abstract

The present invention relates to a method for treating contaminants in electronic wastewater to an ultra-low concentration level by using a microfiltration membrane bioreactor process and a selective heavy metal removal process, in which an organic material, a floating material, nitrogen, and phosphorus are treated and also the floating material is separated from microorganism sludge in a microfiltration membrane bioreactor process, and an interfering reaction is prevented from occurring during reaction of a heavy metal removal agent in a subsequent process, thereby enabling multiple types of heavy metals to be treated to an ultra-low concentration level. According to a preferred embodiment of the present invention, provided is a method for treating wastewater containing an organic material, nitrogen, phosphorus and heavy metals in an electronic wastewater treatment process, the method comprising the steps of: (a) collecting generated wastewater in a flow equalization tank; (b) removing an organic material, nitrogen, and phosphorus by passing the wastewater, fed from the flow equalization tank, through a biological treatment tank sequentially including an anaerobic tank, an anoxic tank, and an aerobic tank equipped with a precise filtration membrane; (c) removing heavy metals by mixing the wastewater, treated in the biological treatment tank, with a heavy metal removal agent in a heavy metal treatment tank; (d) flocculating sludge in the wastewater, treated in the heavy metal treatment tank, in a sludge sedimentation tank, removing the sludge, and discharging sludge-free treated water; and (e) removing a fine floating material and a dissolved material by sequentially passing the treated water, from which the sludge has been removed in the sludge sedimentation tank, through a sand filter and an activated carbon filter, and discharging treated water.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic waste water treatment apparatus for treating an electronic wastewater,

The present invention relates to a method for treating contaminants mixed with electronic wastewater at a low concentration, and more particularly, to a method for treating organic matter, suspended matter, nitrogen and phosphorus in a microfiltration membrane bioreactor, separating suspended solids in the treated water and microbial sludge The microfiltration membrane bioreaction process and the selective heavy metal removal process are applied to prevent the interference of the heavy metal remover in the subsequent stage so that the heavy metals can be treated at a low concentration, and the pollutants in the electronic wastewater are treated at a low concentration .

Domestic and overseas environmental laws and regulations tend to diversify items to be processed and the level of processing to be tailored to the surrounding environment. Developed countries such as the United States and the European Union (EU) are strengthening emissions and treatment standards through industrial wastewater toxicity assessments. Among the various industrial wastewater, electronic wastewater often contains various heavy metals, and treatment thereof is an indispensable item.

Also, because the electronics industry uses a large amount of water, not only the water cost but also the corresponding wastewater treatment costs can be incurred, which can increase manufacturing costs and weaken competitiveness. Therefore, in recent years, technologies for electronic wastewater treatment have been developed in the direction of not discharging wastewater or reusing wastewater.

In addition to the above-mentioned heavy metals, traditional pollutants such as suspended solids (SS), chemical oxygen demand (COD), nitrogen (N) and phosphorus (P) You need to handle it properly.

COD, N, P, and other conventional pollutants have recently been attracting attention due to the advantages of replacing existing sedimentation basins and dramatically reducing suspended solids in treated water. In particular, the economical advantage of biological treatment processes combined with membrane technology has led to explosive growth of new bioreactor membrane bioreactor (MBR) variants.

Conventional heavy metal removal methods include an ion exchange resin method in which coagulation / precipitation using iron or aluminum type flocculant is used, or an ion exchange resin method in which ionic substances including heavy metals are adhered to cation and anion resins to remove them, And reverse osmosis to remove all of the substances. However, these methods have disadvantages in that the treatment efficiency is not constant (coagulation / sedimentation method, ion exchange resin method), excessive installation and operation costs are required (reverse osmosis method) because substances other than heavy metals that are not required to be treated are removed together.

As a background of the present invention, Patent Document No. 2012-0069895 "Waste Water Treatment Method Containing Heavy Metals and Its Treatment Apparatus" (Patent Document 1) is known. In the background art, collecting waste water discharged from a factory and containing heavy metals; Generating air bubbles from waste water discharged from a factory to the collected wastewater; Reacting the heavy metal with the waste gas filled in the bubbles to adsorb the heavy metal to the bubbles; Floating the bubble adsorbed by the heavy metal to remove the bubble; And discharging the wastewater from which the bubbles have been removed.

However, in the background art, the heavy metal is reacted with the waste gas to adsorb the heavy metal by adsorbing the heavy metal, so that the heavy metal can not be selectively removed, and there is a problem that the removal efficiency is limited only by adsorbing and removing the heavy metal .

Patent Publication No. 2012-0069895 "Wastewater Treatment Method Containing Heavy Metals and Its Treatment Apparatus"

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide a microfiltration membrane biological reaction step for passing biological treatment and microfiltration membrane prior to the heavy metal treatment step and treating organic matters, suspended solids, nitrogen, And it is possible to remove pollutants in the electronic wastewater by applying a microfiltration membrane bioreaction process and a selective heavy metal removal process that can treat various kinds of heavy metals at a low concentration by preventing interferences during the reaction of the heavy metal remover in the subsequent stage. And a method for processing the data.

A method for treating wastewater containing organic matter, nitrogen, phosphorus, and heavy metals in an electronic wastewater treatment process, comprising the steps of: (a) collecting generated wastewater in a flow rate adjustment tank; (b) removing the organic matter, nitrogen and phosphorus from the wastewater supplied from the flow rate adjusting tank through the biological treatment tank consisting of an aerobic tank, anoxic tank and aerobic tank with a microfiltration membrane; (c) mixing wastewater treated in the biological treatment tank with a heavy metal removal agent in a heavy metal treatment tank to remove heavy metals; (d) treating the wastewater treated in the heavy metal treatment tank with sludge in a sludge settling tank to treat sludge and discharging treated water from which sludge has been removed; (e) treating the sludge settling tank with sludge-removed treated water in order through a sand filter and an activated carbon filter in order to treat fine suspensions and dissolved substances, and to discharge treated water. And a method for removing contaminants in electronic wastewater at a low concentration by applying a selective heavy metal removal process.

The present invention also provides a method for treating pollutants in electronic wastewater at a low concentration by applying a microfiltration membrane bioreaction process and a selective heavy metal removal process, characterized in that treated water is transported from an oxic tank to an anaerobic tank and a certain amount of sludge is disposed of and treated I want to.

In the step (b), microfiltration is a microfiltration hollow fiber membrane or an ultrafiltration hollow fiber membrane. A microfiltration membrane bioreaction process and a selective heavy metal removal process are applied to treat a pollutant in electronic wastewater at a low concentration .

Also, in the step (c), a heavy metal removing agent is a dithiocarbamate-containing heavy metal removing agent, and a method for treating contaminants in electronic wastewater at a low concentration by applying a selective filtering metal removal step and a selective heavy metal removal step do.

Further, in the step (c), the DTC-containing heavy metal scavenger is used at 20 to 22 times the total contained mass of the divalent heavy metal to be treated. In the microfiltration membrane bioreaction step and the selective heavy metal removal step, And to provide a method for treating pollutants at a low concentration.

In step (d), the flocculant and the flocculant are coagulated by sequentially treating the flocculant and the flocculant in the sludge settling tank. The microfiltration membrane biological reaction process and the selective heavy metal removal process are applied to treat the pollutants in the electronic wastewater at low concentration .

In the step (e), the treated water having passed through the sand filter or the activated carbon filter is returned to the flow rate adjusting tank for reprocessing. The microfiltration membrane biological reaction process and the selective heavy metal removal process are applied to remove contaminants in the electronic waste water And to provide a method for treatment at a low concentration.

In the step (e), the sand filter and the activated carbon filter are excluded. In step (d), a separation membrane is formed in the sludge settling tank to coagulate the sludge to treat the sludge and discharge the treated water from which the sludge has been removed The present invention provides a method for treating contaminants in electronic wastewater at a low concentration by applying a microfiltration bioreaction process and a selective heavy metal removal process.

The microfiltration membrane bioreactor and the selective heavy metal removal process of the present invention can be used to treat pollutants in the electronic wastewater at low concentrations. The microfiltration process includes a microfiltration membrane bioreactor stage to pass biological treatment and microfiltration membrane, It is possible to separate the suspended matter and the microbial sludge from the organic matter, suspended matter, nitrogen, and phosphorus in the subsequent step, thereby preventing the interference of the heavy metal removing agent in the subsequent step, thereby enabling the treatment of various heavy metals at a low concentration .

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments of the invention and, together with the description, serve to explain the principles of the invention, Shall not be construed as limiting.
1 is a flowchart schematically showing a first embodiment of a method for treating contaminants in electronic wastewater according to the present invention at low concentration.
2 is a flowchart schematically showing a second embodiment of a method for treating contaminants in electronic wastewater according to the present invention at a low concentration.
FIG. 3 is a graph showing changes in zinc concentration with respect to the pH concentration of the DTC-based heavy metal remover.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the embodiments shown in the accompanying drawings, but the present invention is not limited thereto.

Hereinafter, the technical structure of the present invention will be described in detail with reference to the preferred embodiments.

In the present invention, a microfiltration membrane biological reaction step is performed so as to pass a biological treatment and a microfiltration membrane before a heavy metal treatment step to separate suspended matter and microbial sludge by treating organic matter, suspended matter, nitrogen and phosphorus in the wastewater, The present invention relates to a microfiltration membrane bioreactor and a method for selectively removing heavy metals from a wastewater, thereby preventing contamination during reaction and treating various heavy metals at a low concentration.

Fig. 1 is a flowchart schematically showing a first embodiment of a method for treating contaminants in electronic wastewater according to the present invention at low concentration.

In the first embodiment of the present invention, first, the generated electromagnetic wastewater is collected in the flow rate control tank 10 (a).

The wastewater is collected in the flow rate adjusting tank 10 of a predetermined size so that the flow rate of the wastewater can be adjusted and supplied at a subsequent stage.

Then, the wastewater supplied from the flow rate adjusting tank 10 is passed through the biological treatment tank 20 to remove organic matter, nitrogen, and phosphorus, and remove suspended matters (b).

The biological treatment tank 20 is composed of an anaerobic tank 21, an anoxic tank 22 and an aerobic tank 23 in order to allow the wastewater to pass through in succession.

In the anaerobic tank 21, some organic substances are converted into methane and the like in the reducing condition by the anaerobic microorganism. In the anoxic tank 22, nitric acid (NO ₃ ^- ) produced in the aerobic tank 23 by the denitrifying microorganism, Is converted into nitrogen gas (N ₂ ), organic matter is used and removed, and the aerobic tank 23 is converted into carbon dioxide (CO ₂ ) by aerobic microorganisms and is removed.

In the case of nitrogen, ammonia (NH ₄ ⁺ ) is converted into nitric acid (NO ₃ ^- ) by the nitrifying microorganism in the aerobic tank 23 as described above. The treatment water is transported from the oxic tank 23 to the anaerobic tank 21, The sludge is discarded and treated, and nitrate is returned from the anoxic tank 23 to the nitrogen gas in the anaerobic tank 22 through the anaerobic tank 21, thereby being removed.

In the case of phosphorus removal, phosphorus is consumed in the anaerobic tank 21 and exhausted from the aerobic tank 23 through the anoxic tank 22, or phosphorus ingested in the anaerobic tank 23, Is removed by discarding the microbial sludge in the oxic tank (23). The wastewater thus treated is separated from the microbial sludge and floating matter by using the microfiltration membrane 231 installed in the oxic tank 23 and discharged to the next stage.

In this case, the microfiltration membrane 231 is a hollow fiber membrane formed of a hollow having a hollow therein and a plurality of holes formed on the surface thereof, and it is possible to use various kinds of known filtration membranes including a normal hollow fiber membrane. A filtration hollow fiber membrane may be used.

In addition, membrane separation techniques are classified into general filtration, microfiltration, ultrafiltration and reverse osmosis. Depending on the size of the material to be separated, ordinary filtration is up to 10 μm, microfiltration is up to 30 nm, ultrafiltration is up to 2 nm, Is in the relationship of reverse osmosis.

Therefore, the microfiltration hollow fiber membrane can be excluded from most microorganisms, and the ultrafiltration hollow fiber membrane can be used for the precise removal of microorganisms by the user's choice because the pore size is smaller than that of the microfiltration hollow fiber membrane.

Thereafter, the heavy metals are removed from the waste water treated in the biological treatment tank 20 by mixing the heavy metal removal agent in the heavy metal treatment tank 30 (c).

The treated water treated by the microfiltration membrane 231 in the oxic tank 23 is transferred to the heavy metal treatment tank 30 for the heavy metal treatment and the pH of the treated water is adjusted to the neutral pH range And a step of mixing a heavy metal scavenger to form fine flocs.

In conventional coagulation facilities, the wastewater is once made alkaline with NaOH, and the pH changes to acidic state due to the reaction of acidic sulphate, PAL, etc. However, NaOH must be mixed again in order to make the pH neutral during the final treatment In the present invention, the pH of the treated water is in the neutral range through the biological treatment in the biological treatment tank 20 of the step (b), so that no pH adjustment is required.

A variety of known heavy metal removers can be used. In particular, a heavy metal scavenger mainly composed of dithiocarbamate (DTC), which is known to have a function of removing heavy metals, is injected to react with heavy metals to remove heavy metals can do.

 An example of a DTC (dithiocarbamate) series is Nalco's Nalmet, which selectively removes diatomic heavy metals, and DTC is the main ingredient in most products.

In the present invention, one of the major reasons for using the dithiocarbamate (DTC) series as a heavy metal remover is to replace the NaOH since the DTC chemical is a strong alkali, and after the heavy metal removal reaction, This is because the final treatment number is in the neutral range.

Therefore, this treatment method can treat the organic matter, nitrogen, phosphorus and heavy metals in the wastewater simultaneously with high removal performance through steps (b) and (c).

Further, the heavy metal removing agent of the dithiocarbamate (DTC) series can be used at a ratio of 20 to 22 times the total contained mass of the bivalent heavy metals to be treated.

This is because the reaction depends on the amount of DTC (about 40% ~ 60%), the amount of heavy metal, and the foreign substance in water. Therefore, it is suggested that the efficiency is maintained. Considering that the value is less than 20 times, it is not enough to handle 2 heavy metals. If it is used more than 22 times, it becomes less efficient. Therefore, it is preferable to use 20 to 22 times.

FIG. 3 is a graph showing changes in zinc concentration with respect to the pH concentration of the DTC-based heavy metal remover.

When a heavy metal removing agent is used as a dithiocarbamate (DTC) -based chemical having a strong chelating ability against a heavy metal of a bivalent metal, as shown in Fig. 3, it is possible to remove the ten different heavy metals from the reaction optimization laboratory test The condition was 7 ~ 9, and the removal efficiency was the maximum at the acidic pH 6 or less in the case of zinc alone.

(B) and (c) are sequentially performed so that organic matter, nitrogen and phosphorus are pretreated in the biological treatment tank 20 by biological treatment, and the heavy metals are treated in the heavy metal treatment tank 30 When the heavy metal is first removed by pretreatment, the biological treatment is placed in the preceding stage because the high concentration of organic matter, nitrogen, phosphorus, etc. contained in the waste water delay the reaction with the heavy metal removing agent.

Thereafter, the wastewater treated in the heavy metal treatment tank 30 is sludge coagulated in the sludge settling tank 40 to treat the sludge and discharge the treated water from which the sludge has been removed (d).

In step (c), the flocs generated in step (d) are increased in size to precipitate in the sedimentation tank 40 to form a chemical sludge, thereby finally removing heavy metals.

At this time, the flocculant and the flocculant aid may be treated in order to facilitate flocculation in the sludge settling tank 40.

As the coagulant, various known products such as sulfuric acid alumina, PAC, and aluminum-based coagulant (PAC) can be used.

The flocculant is injected in this manner to form a larger flap, and then the size of the flap is maximized by using an aggregating aid. The coagulant may be a cationic, anionic or amphoteric polymer. The resulting floc is easily precipitated in a settling tank and the heavy metal is finally removed in the form of chemical sludge.

Lastly, in the first embodiment of the present invention, unlike the second embodiment, the treated water from which sludge has been removed from the sludge settling tank 40 is passed through the sand filter 50 and the activated carbon filter 60 in order, (E) of treating the material and discharging the treated water is further constituted.

By sequentially passing through the sand filter 50 and the activated carbon filter 60 the treated water from which the heavy metal has been removed in this way, the floating matters containing micro-heavy metals, dissolved substances, odors, etc., And finally discharged to be discharged.

Further, the treated water having passed through the sand filter 50 or the activated carbon filter 60 can be transported to the flow rate adjustment tank 10 for reprocessing.

In the case of the sand filter 50 or the activated carbon filter 60, since it is likely to be occluded over time, it is periodically returned to the flow rate adjusting tank 10 to be backwashed, The filter 60 can be regenerated and the waste water can be reprocessed at the same time.

<Examples>

Table 1 below shows the concentrations of heavy metals including copper 90 ppb, iron 150 ppb, zinc 350 ppb, manganese 250 ppb, nickel 10 ppb, organic matter (biochemical oxygen demand, COD) 318 ppm, total nitrogen 23 ppm and a total of 12 ppm were treated by the method of the first embodiment of the present invention.

Chemicals Goals (mg / L) Influent (mg / L) Effluent (mg / L) Cu 0.0034 0.09 0.0004 Fe 0.6 0.15 &Lt; 0.1 Zn 0.0036 0.35 <0.0001 Mn 0.01 0.25 <0.01 Ni 0.01 0.01 <0.0002 Pb - 0.00023 <0.0002 COD 225 318 <25 Total inorganic nitrogen 17 23 <1 Phosphorus 0.6 1.2 0.03

 The concentration of heavy metals was removed to 0.4 ppb of copper, 100 ppb of iron, 0.1 ppb of zinc, 10 ppb of manganese, and 0.2 ppb of nickel, and the organic matter (biochemical oxygen demand, COD) 1 ppm of nitrogen and 0.03 ppm of total or less.

2 is a flowchart schematically showing a second embodiment of a method for treating contaminants in electronic wastewater according to the present invention at a low concentration.

The first embodiment and the second embodiment of the present invention are identical in the steps (a), (b) and (c) with the steps (A), (B) and (C) The step (e) of passing the sludge-removed treated water after the treatment step (d) in the sedimentation tank (40) through the sand filter (50) and the activated carbon filter (60) In step (D) without the step of passing through the filter and the activated carbon filter, a separate separation membrane 43 is formed in the sludge settling tank 40.

2, in order to treat the suspended substances to a higher level according to the treatment level, the separation membrane 43 is not moved in the step (D) without the sand filter and the activated carbon filter step of the first embodiment, Can be constructed and simplified.

The microfiltration membrane bioreactor and the selective heavy metal removal process of the present invention as described above can be used to treat contaminants in the electronic wastewater at a low concentration. The microfiltration process includes a microfiltration membrane bioreaction step It is very useful to treat the organic matter, suspended matter, nitrogen, and phosphorus in the wastewater to separate the suspended matter and the microbial sludge so as to prevent the interference of the heavy metal remover in the subsequent step, thereby treating various heavy metals at a low concentration It is effective.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the above teachings. will be. The invention is not limited by these variations and modifications, but is limited only by the claims appended hereto.

10: Flow regulator
20: Biological treatment tank
30: Heavy metal treatment tank
40: sludge settling tank
43: Membrane
50: Sand filter
60: activated carbon filter

Claims (13)

A method for treating wastewater containing organic matter, nitrogen, phosphorus, and heavy metals in an electronic wastewater treatment process,
(a) collecting the generated wastewater into a flow rate regulator (10);
(b) The wastewater supplied from the flow rate adjusting tank 10 is passed through the biological treatment tank 20 composed of the aerobic tank 23, in which the anaerobic tank 21, the anoxic tank 22 and the microfiltration membrane 231 are constituted in sequence. ;
(c) mixing wastewater treated in the biological treatment tank (20) with heavy metal removal tank (30) to remove heavy metals;
(d) coagulating the sludge in the sludge settling tank (40) with the wastewater treated in the heavy metal treatment tank (30), treating the sludge and discharging the treated water from which the sludge has been removed;
(e) treating the sludge-removed treated water in the sludge settling tank (40) through the sand filter (50) and the activated carbon filter (60) in order to treat the fine suspended matter and the dissolved substance and discharge the treated water Wherein the microfiltration membrane bioreaction process and the selective heavy metal removal process are applied to treat pollutants in electronic wastewater at low concentrations. The method according to claim 1,
In the step (b)
The treatment water is transported from the aerobic tank 23 to the anaerobic tank 21 and a certain amount of sludge is treated for disposal to treat the pollutants in the electronic waste water at a low concentration by applying the microfiltration membrane bioreaction process and the selective heavy metal removal process How to. The method according to claim 1,
In the step (b)
Wherein the microfiltration membrane (231) is a microfiltration hollow fiber membrane or an ultrafiltration hollow fiber membrane. The microfiltration membrane bioreaction process and the selective heavy metal removal process are applied to treat pollutants in electronic wastewater at a low concentration. The method according to claim 1,
In the step (c)
Wherein the heavy metal remover is a dithiocarbamate (DTC) -removing heavy metal remover, wherein the microfiltration bioreaction process and the selective heavy metal removal process are applied to treat low-concentration pollutants in the electronic wastewater. The method of claim 4,
In the step (c)
A method for treating contaminants in electronic wastewater at a low concentration by applying a microfiltration membrane bioreaction process and a selective heavy metal removal process characterized in that the DTC-containing heavy metal removal agent uses 20 to 22 times the total contained mass of the bivalent heavy metals to be treated . The method according to claim 1,
In step (d)
Wherein the sludge settling tank (40) treats the flocculant and the flocculant aid in order to flocculate the flocculant and the flocculant aid so that the pollutants in the electronic wastewater are treated at a low concentration by applying the microfiltration membrane bioreactor and the selective heavy metal removal process. The method according to claim 1,
In the step (e)
The treated water passing through the sand filter 50 or the activated carbon filter 60 is transported to the flow rate regulator 10 for reprocessing. The microfiltration membrane bioreaction process and the selective heavy metal removal process are applied to remove contaminants Is treated at a low concentration. A method for treating wastewater containing organic matter, nitrogen, phosphorus, and heavy metals in an electronic wastewater treatment process,
(A) collecting the generated wastewater into a flow rate regulator (10);
(B) The wastewater supplied from the flow rate adjusting tank 10 is passed through the biological treatment tank 20 including the aerobic tank 21, the anoxic tank 22 and the aerobic tank 23 composed of the microfiltration membrane 231, ;
(C) mixing wastewater treated in the biological treatment tank (20) with heavy metal removal tank (30) to remove heavy metals;
(D) coagulating the sludge in the sludge settling tank (40) having the separation membrane (43) inside the wastewater treated in the heavy metal treatment tank (30), and treating the sludge and discharging the treated water from which the sludge has been removed Wherein a microfiltration membrane bioreaction process and a selective heavy metal removal process are applied to treat contaminants in electronic wastewater at low concentrations. The method of claim 8,
In step (B)
The treatment water is transported from the aerobic tank 23 to the anaerobic tank 21 and a certain amount of sludge is treated for disposal to treat the pollutants in the electronic waste water at a low concentration by applying the microfiltration membrane bioreaction process and the selective heavy metal removal process How to. The method of claim 8,
In step (B)
Wherein the microfiltration membrane (231) is a microfiltration hollow fiber membrane or an ultrafiltration hollow fiber membrane. The microfiltration membrane bioreaction process and the selective heavy metal removal process are applied to treat pollutants in electronic wastewater at a low concentration. The method of claim 8,
In step (C)
Wherein the heavy metal remover is a dithiocarbamate (DTC) -removing heavy metal remover, wherein the microfiltration bioreaction process and the selective heavy metal removal process are applied to treat low-concentration pollutants in the electronic wastewater. The method of claim 11,
In step (C)
A method for treating contaminants in electronic wastewater at a low concentration by applying a microfiltration membrane bioreaction process and a selective heavy metal removal process characterized in that the DTC-containing heavy metal removal agent uses 20 to 22 times the total contained mass of the bivalent heavy metals to be treated . The method of claim 8,
In step (D)
Wherein the sludge settling tank (40) treats the flocculant and the flocculant aid in order to flocculate the flocculant and the flocculant aid so that the pollutants in the electronic wastewater are treated at a low concentration by applying the microfiltration membrane bioreactor and the selective heavy metal removal process.

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