JP6370629B2 - Waste water treatment system and waste water treatment method using the same - Google Patents

Description

  The present invention relates to a wastewater treatment system and a wastewater treatment method using the same, and more particularly to a wastewater treatment system for purifying flush water during aluminum surface treatment and a wastewater treatment method using the same.

  Conventionally, surface treatments such as colored chemical conversion treatment and anodizing (anodization) have been performed on aluminum parts (hereinafter also referred to as aluminum members) that require high environmental durability. In such a surface treatment, in order to improve the activation of the surface of the component, the component is immersed in a treatment solution containing target components such as nitric acid and chromic acid, and then immersed in a water washing tank and washed with water. The washing water in the washing tank needs to purify the washing water because the water quality deteriorates due to the target component brought into the washing tank from the surface treatment tank and the quality of the surface treatment cannot be maintained.

  As such a purification treatment, the washing water of the phosphate film conversion treatment of the metal molding is taken out, and after adjusting its pH to an acidic range, treatment with a reverse osmosis membrane (RO membrane) and reuse can be performed. Known (for example, Patent Document 1). Further, there is known a process of reusing the permeated water of a reverse osmosis membrane as reclaimed water after coagulating and separating the total drainage containing organic matter from the pulp and paper factory in the acidic region (for example, Patent Document 2).

  In such a treatment, it is difficult to sufficiently separate and remove ions to be removed such as nitrate ions derived from the target component contained in the washing water with a reverse osmosis membrane. In addition, the precipitate formed by the coagulation separation may cause problems such as clogging in the reverse osmosis membrane. As another treatment, it is also possible to treat the washing water with an ion exchange resin. However, even when an ion exchange resin is used, there is a possibility that the ion exchange resin is loaded with a high concentration of ions to be removed and breaks through at an unexpected time.

JP 2001-164389 A JP 2013-234468 A

  In view of the above circumstances, the present invention efficiently recovers and reuses the target component from the washing water after the coating treatment of the aluminum member, maintains the quality of the surface treatment, and reduces the deterioration rate of the equipment used. An object is to provide a treatment system and a wastewater treatment method using the treatment system.

  In order to achieve the above object, the wastewater treatment system according to the present invention adds a neutralizing agent to the raw acid wastewater in the first acidic region containing aluminum ions and nitrate ions, thereby adjusting the pH of the raw wastewater to a neutral region. The first adjustment tank to be increased and discharged as neutralized wastewater, and the neutralized wastewater are received, and the hydroxide of aluminum ions formed in the neutralized wastewater is separated and discharged as separated wastewater. A solid-liquid separation tank, a second adjustment tank that receives the separation wastewater, lowers the pH of the separation wastewater to a second acidic region, dissolves remaining hydroxide, and discharges it as acidic wastewater; and An ion removing device that receives acid waste water, removes ions to be removed from the acid waste water, and discharges the purified waste water as purified water.

  In another aspect, the present invention is provided in a surface treatment apparatus comprising at least a surface treatment tank for coating an aluminum member and a primary water washing tank for washing the coated aluminum member with washing water, This is flush water discharged from the primary flush tank, and the purified water can be reused as flush water in the first flush tank.

  If it is such a form, it will become possible to provide continuous purification and reuse of the washing water, maintain the quality of the washing water, and maintain the quality of the surface treatment. In addition, it is not necessary to collect or replenish flush water in a large primary flush tank in a batch to purify flush water. Thereby, the running cost of the surface treatment can be reduced.

  In another aspect, the present invention provides a surface treatment tank for coating an aluminum member, a primary water washing tank for washing the coated aluminum member with washing water, and washing the aluminum member washed with the primary water with washing water. A secondary water rinsing tank, the raw drainage is rinsing water discharged from the primary rinsing tank, and the purified water is reused as rinsing water in the secondary rinsing tank, The flush water in the second flush tank can be reused as flush water in the primary flush tank.

  In such a form, it becomes possible to provide a continuous purification and reuse including the flush water in the secondary flush tank, that is, to provide a recycling system, and maintain the quality of the flush water, that is, the quality of the surface treatment. be able to. In addition, it is not necessary to industrially discard and replenish flush water in large primary and secondary flush tanks in order to purify flush water. Thereby, the running cost of the surface treatment can be reduced.

  The ion removing device may be a first ion removing device and a second ion removing device, the first removing device may include a reverse osmosis membrane, and the second ion removing device may include an ion exchange resin. Is preferred.

  Moreover, it is preferable that said 1st acidic region is pH2 or more exceeding pH0, said neutral region is pH6 or more and pH7 or less, and said 2nd acidic region is pH4 or more and pH5 or less.

  Within such a numerical range, aluminum ions are efficiently removed from the raw waste water, nitrate ions are efficiently removed by the reverse osmosis membrane and / or ion exchange resin, and clogging of the reverse osmosis membrane occurs. The fear can be reduced.

  Moreover, this invention is another form. WHEREIN: The said flush water is stored as said raw waste water, it sends to said 2nd adjustment tank, The raw waste water tank which lowers | hangs the pH of the said separated waste water to a 2nd acidic region The coating treatment may be anodizing treatment or colored chemical conversion treatment, and the neutralizing agent may be sodium hydroxide.

  In such a form, removal target ions such as fluoride ions and sulfate ions contained in the washing water after the anodizing treatment or the color conversion treatment are also efficiently removed by the reverse osmosis membrane and / or the ion exchange resin. Can do.

  Furthermore, this invention is a waste water treatment method in another aspect. The wastewater treatment method according to the present invention increases the pH of the raw wastewater to a neutral range by adding a neutralizing agent to the raw acid wastewater in the first acidic region containing aluminum ions and nitrate ions. A first adjustment step to be discharged as a solid-liquid separation step of receiving the neutralized wastewater, separating the hydroxide of the aluminum ions formed in the neutralized wastewater, and discharging the separated wastewater; Receiving the separated wastewater, lowering the pH of the separated wastewater to the second acidic region, dissolving the remaining hydroxide, and discharging as acidic wastewater, receiving the acidic wastewater, An ion removal step of removing ions to be removed from the acid waste water and discharging the purified water as purified water.

  In light of the above object, according to the wastewater treatment system and the wastewater treatment method using the same according to the present invention, the target component can be efficiently recovered and reused from the washing water after the coating of the aluminum member, and the surface treatment While maintaining the quality of the device, it is possible to reduce the deterioration rate of the equipment used.

FIG. 1 is a conceptual diagram illustrating an outline of a first embodiment of a wastewater treatment system and a wastewater treatment method using the wastewater treatment system according to the present invention. FIG. 2 is a conceptual diagram for explaining the first embodiment in more detail with respect to the wastewater treatment system and the wastewater treatment method using the wastewater treatment system according to the present invention. FIG. 3 is a graph showing the relationship between the pH of anions and the removal rate for a wastewater treatment system and a wastewater treatment method using the wastewater treatment system according to the present invention. FIG. 4 is a conceptual diagram illustrating a second embodiment of a wastewater treatment system and a wastewater treatment method using the wastewater treatment system according to the present invention. FIG. 5 is a conceptual diagram illustrating a third embodiment of the wastewater treatment system and the wastewater treatment method using the wastewater treatment system according to the present invention.

[First embodiment]
Hereinafter, a first embodiment of a wastewater treatment system according to the present invention will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited by embodiment described below.

  FIG. 1 shows a first embodiment of a wastewater treatment system according to the present invention. A wastewater treatment system 1 shown in FIG. 1 has a wastewater treatment facility 2 as a central part, and the configuration thereof will be described later. Moreover, the waste water treatment system 1 is provided together with a surface treatment apparatus for treating an aluminum member, and the surface treatment apparatus includes at least a surface treatment tank 3, a primary water washing tank 4, and a secondary water washing tank 5. In the present specification, the “aluminum member” means aluminum, an aluminum alloy, or a material or component containing them.

First, a surface treatment apparatus provided with the waste water treatment system 1 will be described. The surface treatment tank 3 is a large tank for coating a plurality of aluminum members by a known surface coating process. The surface coating treatment is an electrical or chemical treatment such as anodizing treatment, colored chemical conversion treatment, deoxy soybean which is a pretreatment thereof. The treated water filled in the surface treatment tank 3 includes aluminum ions (Al ³⁺ ), nitrate ions (NO ₃ ⁻ ), fluoride ions (F ⁻ ), sulfuric acid derived from these target components required for the treatment. Ions such as ions (SO ₄ ²⁻ ) and dichromate ions (Cr ₂ O ₇ ²⁻ ), that is, ions to be removed are contained. Since the ions adhere to the surface of the aluminum member and are brought into the primary washing tank, they become ions to be removed in the primary washing tank.

  The primary water rinsing tank 4 is a large tank for washing a plurality of aluminum members, and communicates with the raw drain tank 21 through the line L1 and communicates with the second ion removing device 26 through the line L11. The primary water washing tank 4 wash | cleans the aluminum member surface-treated in the surface treatment tank 3 with the washing water with which the inside was filled. The secondary rinsing tank 5 is a large tank for rinsing a plurality of aluminum members, and the aluminum member washed in the primary rinsing tank 4 is further washed with rinsing water.

  Next, the first embodiment of the waste water treatment system 1 according to the present invention shown in FIG. 1 will be described in more detail with reference to FIG. The wastewater treatment facility 2 constituting the central portion of the wastewater treatment system 1 includes a raw drainage tank 21, a first adjustment tank 22, a solid-liquid separation tank 23, a second adjustment tank 24, and a first ion removal. The apparatus 25 and the 2nd ion removal apparatus 26 are provided at least.

  The raw drain tank 21 is a tank for storing flush water as raw drain, and communicates with the primary flush tank 4 through the line L1, communicates with the first adjustment tank 22 and the line L2, and the second adjustment tank 24. And through the pump P1 and the line L3.

  The first adjustment tank 22 is a tank for adjusting the pH of the raw waste water, and by adding a neutralizing agent to the raw acid waste in the first acidic region containing aluminum ions and nitrate ions, Increase pH to neutral range and discharge as neutralized wastewater. The first adjustment tank 22 communicates with the raw drain tank 21 through the line L1, and communicates with the solid-liquid separation tank 23 through the line L5.

  The first adjustment tank 22 includes a stirrer 22a, a pH sensor 22b, and an alkaline chemical tank 22c. The stirrer 22a stirs the raw waste water and sodium hydroxide that have flowed into the first adjustment tank 22. The pH sensor 22 b monitors the pH of the raw waste water in the first adjustment tank 22. The alkaline chemical tank 22c communicates with the first adjustment tank 22 through the pump P2 and the line L4. The alkaline chemical tank 22c or the pump P2 is electrically connected to the pH sensor 22b.

  The solid-liquid separation tank 23 is a tank for precipitating and removing aluminum hydroxide, receives the neutralized waste water, and separates the hydroxide of aluminum ions formed in the neutralized waste water, Discharge as separated wastewater. The solid-liquid separation tank 23 communicates with the first adjustment tank 22 through the line L5, communicates with the second adjustment tank 24 through the line L6, and communicates with the line L7 for discharging the precipitate.

  The second adjustment tank 24 is a tank for adjusting the pH of the separated wastewater, receives the separated wastewater, lowers the pH of the separated wastewater to the second acidic region, and dissolves the remaining hydroxide. And discharged as acidic wastewater. The second adjustment tank 24 communicates with the solid-liquid separation tank 23 through the line L6, communicates with the raw drain tank 21 through the pump P1 and the line L3, and communicates with the first ion removal device 25 through the pump P3 and the line L8. ing.

  The second adjustment tank 24 includes a stirrer 24a and a pH sensor 24b. The agitator 24 a agitates the separated waste water and the raw waste water that have flowed into the second adjustment tank 24. The pH sensor 24b monitors the pH of the waste water in the second adjustment tank 24. The raw drain tank 21 or the pump 1 is electrically connected to the pH sensor 24b.

  The first ion removing device 25 includes a known reverse osmosis membrane and is a device for separating and removing a target component. The 1st ion removal apparatus 25 receives the said acidic waste_water | drain, removes the removal object ion in the said acidic waste_water | drain, and discharges it as 1st purified water. The first ion removing device 25 communicates with the second adjustment tank 24 through the pump P3 and the line L8, communicates with the second ion removing device 26 through the line L9, and communicates with the line L10 for discharging concentrated waste water. doing.

  The second ion removing device 26 is a device that includes a known anion and / or cation exchange resin and separates and removes the target component. The second ion removing device 26 receives the first purified water, removes ions to be removed from the first purified water, and discharges the second purified water as second purified water. The second ion removing device 26 communicates with the first ion removing device 25 through the line L8, and communicates with the primary water washing tank 4 through the line L11.

  A first embodiment of a wastewater treatment method using the wastewater treatment system 1 having the above configuration will be described in detail with reference to the accompanying drawings. The wastewater treatment method of the present embodiment includes an original wastewater storage process, a first pH adjustment process, a solid-liquid separation process, a second pH adjustment process, a first removal process, and a second removal process. And at least. Since the wastewater treatment method is performed in cooperation with the surface treatment method of the aluminum member, each process of the wastewater treatment method will be described after the outline of the surface treatment method is described.

  In the surface treatment process of the surface treatment method, the aluminum member is coated by immersing it in a treatment liquid containing a target component required for the surface coating treatment filled in the surface treatment tank 3. Examples of the surface treatment include electrical or chemical coating treatment such as anodizing treatment (anodizing treatment) and colored chemical conversion treatment. The treatment liquid contains ions such as fluoride ions, sulfate ions, and dichromate ions in addition to aluminum ions and nitrate ions derived from the target components required for the treatment. After the surface treatment step, the treated aluminum member is taken out from the surface treatment tank 3 and supplied to the primary water washing tank 4.

  Next, in the primary water washing step, the surface-treated aluminum member is washed with water by immersing it in flush water filled in the primary water washing tank 4. The flush water in the primary flush tank 4 contains the target component adhering to the aluminum member by the surface treatment, and its pH is lowered to the first acidic range. For this reason, in a primary water washing process, while supplying flush water to the original drainage tank 21, it takes in purified water from the 2nd ion removal apparatus 26, and reuses it as flush water. That is, the primary rinsing tank 4 discharges used or used rinsing water as raw effluent through the line L1 to the raw drain basin 21, and the ions to be removed from the original effluent through the line L11 from the second ion removing device 26. Incorporate purified water that has been removed. Thereby, circulation reuse of the flush water of the primary flush tank 4 is enabled. In this step, it is possible to eliminate the need for collective industrial waste treatment for purifying a large amount of flush water filled in the large primary flush tank 4. As a result, the running cost of the surface coating process can be reduced.

  In the secondary water washing step, the aluminum member washed in the primary water washing tank 4 is immersed in the washing water filled in the secondary water washing tank 5 to perform water washing. The flush water in the secondary flush tank 5 is purified by circulating reuse of flush water used in the primary flush process. For this reason, the quantity of the target component brought into the secondary flush tank 5 is also small by the aluminum member flushed in the primary flush tank 4. As a result, the quality of the flush water used for the secondary flush treatment can be maintained, and the interval between industrial waste treatments can be increased. Moreover, the quality of the surface treatment of the secondary water washing treatment can be maintained. As a result, the running cost of the surface coating process can be reduced.

  In the raw wastewater saving process of the wastewater treatment method, the flush water discharged from the primary water washing process is received, stored in the raw drainage tank 21, supplied to the first pH adjustment process as the raw wastewater, and the second pH Discharge to the adjustment process. That is, the raw drainage tank 21 stores the flush water flowing in from the line L1 as raw drainage, supplies it to the first adjustment tank 22 through the line L2, and supplies it to the second adjustment tank 24 through the pump P1 and the line L3. Supply raw wastewater as pH adjuster. The raw wastewater stored in the raw drainage tank 21 indicates the first acidic region due to the ion concentration of the ions to be removed contained. In this step, the pH of the raw waste water is maintained in the first acidic region for use in the second pH adjustment step described later.

  The first acidic region is not particularly limited because it affects the type of surface treatment and the degree of water washing. More specifically, the first acidic range is preferably more than pH 0 and 3 or less, more preferably more than pH 0 and 2 or less.

In the first pH adjustment step, the raw water is received in the first adjustment tank 22 and a neutralizing agent is added to the raw water in the first acidic region containing aluminum ions and nitrate ions, thereby Increase the pH of the wastewater to neutral and discharge as neutralized wastewater. The raw water in the first acidic region containing aluminum ions and nitrate ions flows into the first adjustment tank 22 from the raw water drain tank 21 through the line L1. Therefore, in this step, in the first adjustment tank 22, the pH of the raw waste water is controlled by adding sodium hydroxide (NaOH) in the alkaline chemical tank 22c as the neutralizing agent to the pump 2 and the line L4. The aluminum hydroxide (Al (OH) ₃ ), which is a hydroxide of the aluminum ions, is formed by lowering to a neutral range. In this step, the raw waste water that has been reduced to the neutral range is supplied as neutralized waste water to the solid-liquid separation tank 23 through the line L5. Furthermore, in this step, the pH of the washing water in the first adjustment tank 22 is stirred by the stirrer 22a while being monitored by the pH sensor 22b, and increased until it falls within the range from the first acidic range to the neutral range. Let The raw wastewater that shows neutrality is supplied to the solid-liquid separation process as neutralized wastewater.

  The neutral range of the neutralized wastewater is preferably in the range of pH 5 to pH 12, and more preferably in the range of pH 6 to pH 7. If the pH of the washing water is less than 5, the aluminum ion hydroxide may be dissolved in the neutralized waste water and cannot be separated and removed. When the pH of the washing water exceeds 12, it may be dissolved as aluminate ions.

The neutralizing agent is not limited as long as it is a neutralizing agent capable of forming a precipitate of aluminum ions. Examples of the neutralizing agent include sodium hydroxide (NaOH) and potassium hydroxide (KOH). Of these, sodium hydroxide is preferred. If it is sodium hydroxide, it reacts quickly with aluminum ions to form hydroxides, and cupric ions (Cu ²⁺ ) co-precipitate in the neutral region. Thereby, the copper ion in acidic waste water can also be reduced in the solid-liquid separation tank 23. This contributes to improving the quality of the washing water to be purified.

  The addition amount of the neutralizing agent is not particularly limited as long as it is an addition amount that allows the pH of the raw waste water in the first adjustment tank 22 to be in the neutral range. The pH of the raw wastewater can be monitored by the pH sensor 22b, and a necessary amount for maintaining the neutral region as the neutral wastewater can be added. Thereby, while adjusting pH, the hydroxide of aluminum ion can be formed.

  In the solid-liquid separation step, the neutralized wastewater is received in the solid-liquid separation tank 23, the aluminum ion hydroxide formed in the neutralized wastewater is separated and discharged as separated wastewater. That is, the neutralized waste water that has flowed from the first adjustment tank 22 through the line L5 contains aluminum hydroxide, which is a hydroxide of aluminum ions that has reacted with sodium hydroxide and turned into a solid. The solid-liquid separation tank 23 precipitates aluminum hydroxide, which is a solid material, in the lower part by known solid-liquid separation, and separates it from the supernatant liquid in the upper part. Moreover, the solid-liquid separation tank 23 removes the precipitated sodium hydroxide from the line L7, and supplies the supernatant liquid to the second adjustment tank 24 through the line L6 as separation waste water.

  In the second pH adjustment step, the separation wastewater is received in the second adjustment tank 24, the pH of the separation wastewater is lowered to the second acidic region, the remaining hydroxide is dissolved, and the acid wastewater is obtained. Discharge. The pH of the separated waste water after the solid-liquid separation step indicates a neutral range. For this reason, in this process, an acidic pH adjuster is added to the separated waste water. In this Embodiment, the pH of the flush water in the 2nd adjustment tank 24 is added by adding the raw waste water which shows the 1st acidic region in the original drainage tank 21 through the pump P1 and the line L3 as a pH adjuster. Decreases from the neutral range to the second acidic range. More specifically, the pH of the separated wastewater in the second adjustment tank 24 is stirred by the stirrer 24a while being monitored by the pH sensor 24b until the pH falls within the range from the neutral range to the second acidic range. Reduce. Wash water showing the second acidic region is supplied to the first ion removing device 25.

The pH adjuster is not limited as long as it can dissolve aluminum ion hydroxide. Examples of the pH adjuster include acidic solutions such as hydrochloric acid (HCl), sulfuric acid (H ₂ SO ₄ ), and carbonic acid (H ₂ CO ₃ ) in addition to the raw waste water. Of these, raw wastewater is preferred. If it is a raw waste water, the pH of the separation waste water can be rapidly lowered without increasing the ion concentration in the washing water of the aluminum member. Moreover, since the flush water of the aluminum member is used, it can greatly contribute to the circulation reuse of the flush water of the wastewater treatment system.

  The second acidic region may be an extent capable of dissolving sodium hydroxide while maintaining a high removal rate of nitrate ions. As shown in FIG. 3, the second acidic region of the washing water is preferably in the range of pH 3 to pH 5 and more preferably in the range of pH 4 to pH 5. If the washing water has a pH of less than 3, nitrate ions may not be removed to a desired extent, and the ion exchange resin may easily break through. When the pH of the washing water exceeds 5, aluminum hydroxide remains and the reverse osmosis membrane may be clogged.

In the first removal step, the first ion removal device 25 receives the acidic wastewater, and removes ions to be removed in the acidic wastewater by a known reverse osmosis membrane method, and discharges the first purified water. To do. That is, in the first ion removing device 25, nitrate ions (NO ₃ ⁻ ) in the acidic waste water supplied from the second adjustment tank 24 by applying a predetermined pressure by the pump P3 by a known reverse osmosis membrane method. , Fluoride ions (F ⁻ ), sulfate ions (SO ₄ ²⁻ ), dichromate ions (Cr ₂ O ₇ ²⁻ ) and the like can be removed. The first ion removing device 25 can efficiently remove nitrate ions in addition to fluoride ions and sulfate ions because the pH of the acidic waste water is in the second acidic range. Further, the first ion removing device 25 supplies the acidic water from which ions have been removed by passing through the reverse osmosis membrane to the second ion removing device 26 from the line L9 as the first purified water, so that ions and impurities are present. The concentrated concentrated waste water is discharged from the line L10.

  In the second removal step, the second purified water is received by the second ion removing device 26, the ions to be removed in the first purified water are removed by the conventional ion exchange method, and the second purified water is removed. Discharge as purified water. That is, the second ion removing device 26 removes sodium ions, nitrate ions, and the like in the first purified water flowing from the first ion removing device 25 by an ion exchange method. Since the nitrate ion concentration in the first purified water is lowered by the first ion removing device 25, the second ion removing device 26 can sufficiently remove the ions to be removed without burden. Therefore, the possibility that the ion exchange resin of the second ion removing device 26 breaks through easily can be reduced. The 2nd ion removal apparatus 26 supplies the 1st purified water which permeate | transmitted the anion and / or cation exchange resin to the primary washing tank 4 as a 2nd purified water from the line L11. The 2nd purified water which passed through the 2nd removal process is reused as flush water of a primary washing process.

  As the shape of the ion exchange resin disposed in the second ion removing device 26, a membrane, a fiber, or a liquid can be used. Furthermore, the second ion removing device can include a pH adjusting tank (not shown), and the second purified water whose pH is adjusted to a value suitable for washing can be reused as washing water.

[Second Embodiment]
Next, a second embodiment of the waste water treatment system according to the present invention will be described in detail with reference to FIG. In the present embodiment, the waste water treatment system 100 includes at least a waste water treatment facility 102, and the surface treatment apparatus includes at least a primary water washing tank 104 and a secondary water washing tank 105. In addition, the same reference number is attached | subjected to the component same as 1st embodiment of a waste water treatment system, and those components fulfill | perform the function and function substantially the same as 1st embodiment.
A sign is attached.

  The primary rinsing tank 104 rinses the aluminum member treated in the surface treatment tank 3 with rinsing water. The primary flush tank 104 communicates with the raw drain tank 21 through the line L1, and communicates with the secondary flush tank 105 through the line 112. Moreover, the secondary water washing tank 105 wash | cleans the aluminum member washed with the primary water washing tank 104 with water. The secondary water washing tank 105 communicates with the second ion removing device 126 through the line L111, and communicates with the primary water washing tank 104 through the line L112.

  The waste water treatment facility 102 includes a second ion removal device 126 instead of the second ion removal device 26 of the first embodiment. The waste water treatment facility 102 communicates with the primary flush tank 104 through the inflow line L1, and communicates with the secondary flush tank 105 and the outflow line L111. The waste water treatment facility 102 removes aluminum ions, nitrate ions, fluoride ions, and sulfate ions contained in the flush water of the primary flush tank 104, and then uses the obtained second purified water in the secondary flush tank 105. It is configured to be reused as flush water.

  The 2nd ion removal apparatus 126 is an ion removal apparatus provided with the well-known anion and / or cation exchange resin. The second ion removing device 126 communicates with the first ion removing device 25 through the line L8, and communicates with the secondary water washing tank 105 through the line L111.

  A second embodiment of the wastewater treatment method using the wastewater treatment system 100 having the above configuration will be described in detail. In addition, about this Embodiment, description is abbreviate | omitted about the action mechanism substantially the same as 1st embodiment of the waste water treatment method.

  In the primary water washing step, the aluminum member surface-treated in the surface treatment tank 3 is washed with water. The flush water in the primary flush tank 104 contains the target component adhering to the aluminum member in the surface treatment tank 3, and its pH is lowered to the first acidic range. In this step, in order to make the pH of the rinsing water in the primary rinsing tank 104 neutral, and to remove chemicals that cause a decrease in pH, the rinsing water is discharged to perform the raw drainage saving step, which will be described later. Incorporate water that has undergone the two-water washing process.

  In the secondary washing step, the aluminum member washed in the primary washing tank 104 is immersed in washing water filled in the secondary washing tank 105 and washed. Although the flush water in the secondary flush tank 105 is less than the flush water in the primary flush tank 104, it contains the target component adhering to the aluminum member in the surface treatment tank 3, and its pH is lowered to the first acidic range. doing. For this reason, in this process, in order to make the pH of the rinsing water in the secondary rinsing tank 105 neutral, and to remove chemicals that cause a decrease in pH, the rinsing water is discharged and the raw drainage saving process is performed. The second purified water purified from the second removal step is taken in.

  In the second removal step, sodium ions and nitrate ions in the first purified water after the first removal step are removed in the second removal tank 126 by a known ion exchange method. In the second removal step, since the ion concentration in the first purified water is reduced by the first removal step, ions can be sufficiently removed without burden. Thereby, the possibility that the ion exchange resin of the 2nd ion removal apparatus used for this process may break through can be reduced. The 1st flush water which passed through the 2nd removal process is reused for the secondary flush process mentioned later as the 2nd purified water.

  In the present embodiment, the purified flush water from the second ion removing device 126 flows into the secondary flush tank 105. For this reason, the interval of the industrial waste treatment of the flush water used for the process of the secondary flush tank 105 can be made longer than in the first embodiment. Moreover, it is not necessary to newly install a waste water treatment facility for purifying the flush water in the secondary flush tank 105. Furthermore, it is possible to eliminate the need for a process for producing and discarding the purified water in both the large primary washing tank 104 and the secondary washing tank 105 in a lump.

[Third embodiment]
Next, a third embodiment of the waste water treatment system according to the present invention will be described in detail with reference to FIG. In the present embodiment, the waste water treatment system 200 includes at least a waste water treatment facility 202, and the surface treatment apparatus includes at least a primary water washing tank 204. In addition, the same reference number is attached | subjected to the component same as 1st embodiment of a waste water treatment system, and those components fulfill | perform the function and function substantially the same as 1st embodiment.

  The waste water treatment facility 202 includes a first ion removal device 225 instead of the first ion removal device 25 of the first embodiment. The 1st ion removal apparatus 225 is an ion removal apparatus provided with the conventional reverse osmosis membrane. The first ion removing device 225 communicates with the second adjustment tank 24 through the pump P3 and the line L8, communicates with the primary flush tank 204 through the line L209, and communicates with the line L10 for discharging concentrated waste water. ing.

  A third embodiment of the waste water treatment method using the waste water treatment system 200 having the above configuration will be described in detail. In addition, about this Embodiment, description is abbreviate | omitted about the action mechanism substantially the same as 1st embodiment of the waste water treatment method.

  In the primary water washing step, the surface-treated aluminum member is immersed in the primary water washing tank 204 and washed with water. In this process, flush water is supplied to the raw drain tank 21 as raw waste water, and the first purified water that has passed through the first removal process is taken in as flush water and recycled. Further, the aluminum member after the primary water washing is taken out from the primary water washing tank 204 and supplied to the secondary water washing tank 5.

  In the first removal step, nitrate ions, fluoride ions, and sulfate ions in the acidic wastewater supplied through the second pH adjustment step are removed in the first removal tank 225 by the conventional reverse osmosis membrane method. . In this step, the first purified water after the first removal step is supplied to the primary flush tank 204 as flush water in the primary flush step.

  In the present embodiment, the first ion removing device 225 communicates with the primary washing tank 204 through the line L209, and the washing water after the first removing process is reused as washing water in the primary washing process. Illustrated. The present invention is not limited to this. It is possible to adopt a configuration in which the first ion removing device 225 communicates with the secondary flush tank through a line, and the secondary flush tank communicates with the primary flush tank through another line. In this case, the purified water of the third embodiment can be supplied to the secondary flush tank and reused as flush water, and the flush water from the secondary flush tank can be reused in the primary flush tank.

  According to the wastewater treatment system and the wastewater treatment method using the same according to the present invention, the target component can be efficiently recovered and reused from the washing water after the surface treatment of the aluminum member. In addition, the quality of the surface treatment can be maintained, and the deterioration rate of the equipment used can be reduced.

DESCRIPTION OF SYMBOLS 1,100,200 Wastewater treatment system 2,102,202 Wastewater treatment equipment 3 Surface treatment tank 4,104,204 Primary water washing tank 5,105 Secondary water washing tank 21 Original drainage tank 22 First adjustment tank 22a, 24a Stirrer 22b, 24b pH sensor 22c Alkaline chemical tank 23 Solid-liquid separation tank 24 Second adjustment tank 25, 225 First ion removal device 26, 126 Second ion removal device

Claims (12)

By adding a neutralizing agent to the raw wastewater containing aluminum ions , fluoride ions, sulfate ions and nitrate ions, exceeding pH 0 and having a pH of 2 or less , the pH of the raw waste water is increased to a neutral range, A first adjustment tank to be discharged;
A solid-liquid separation tank that receives the neutralized wastewater, separates the hydroxide of the aluminum ions formed in the neutralized wastewater, and discharges it as separated wastewater;
A second adjustment tank that receives the separated wastewater, lowers the pH value of the separated wastewater to pH 4 to pH 5 that is an acidic region , dissolves remaining hydroxide, and discharges it as acidic wastewater;
By storing the raw wastewater and sending it to the second adjustment tank, a raw drainage tank that lowers the pH value of the separated wastewater to the acidic range;
An effluent treatment system comprising: an ion removal device that receives the acid effluent, removes ions in the acid effluent, and discharges the effluent as purified water. Provided in a surface treatment apparatus comprising at least a surface treatment tank for coating an aluminum member and a primary water washing tank for washing the coated aluminum member with washing water,
The waste water treatment system according to claim 1, wherein the raw waste water is flush water discharged from the primary flush tank, and the purified water is reused as flush water for the first flush tank. A surface comprising a surface treatment tank for coating an aluminum member, a primary water washing tank for washing the coated aluminum member with washing water, and a secondary water washing tank for washing the aluminum member washed with the primary water with washing water. Attached to the processing equipment,
The raw waste water is flush water discharged from the primary flush tank, the purified water is reused as flush water for the secondary flush tank, and the flush water discharged from the second flush tank is the primary The wastewater treatment system according to claim 1, wherein the wastewater treatment system is reused as flush water in a flush tank. The ion removing device comprises a first ion removing device and a second ion removing device,
The wastewater treatment system according to any one of claims 1 to 3, wherein the first removal device includes a reverse osmosis membrane, and the second ion removal device includes an ion exchange resin. Wastewater treatment system according to claim 1 wherein the neutral region is pH6 than pH7 or less. The wastewater treatment system according to claim 2 or 3 , wherein the coating treatment is anodizing treatment or colored chemical conversion treatment, and the neutralizing agent is sodium hydroxide. By adding a neutralizing agent to the raw wastewater containing aluminum ions , fluoride ions, sulfate ions and nitrate ions, exceeding pH 0 and having a pH of 2 or less , the pH of the raw waste water is increased to a neutral range, A first adjustment step to discharge,
A solid-liquid separation step of receiving the neutralized wastewater, separating the hydroxide of aluminum ions formed in the neutralized wastewater, and discharging it as separated wastewater;
Receiving the separated waste water, lowering the pH value of the separated waste water to pH 4 or more and pH 5 or less, which is an acidic region , dissolving the remaining hydroxide, and discharging it as acidic waste water;
Saving the raw wastewater and sending it to the second adjustment step, thereby reducing the pH value of the separated wastewater to the acidic range,
An ion removal step of receiving the acidic wastewater, removing ions in the acidic wastewater, and discharging the purified wastewater as purified water. The raw wastewater generated along with the surface treatment method for performing at least a surface treatment step for coating the aluminum member and a primary water washing step for washing the coated aluminum member with water for washing is treated.
The waste water treatment method according to claim 7, wherein the raw waste water is washed water discharged from the primary washing tank, and the purified water is reused as washing water for the first washing tank. A surface treatment process for coating the aluminum member, a primary water washing process for washing the coated aluminum member with washing water, and a secondary water washing process for washing the primary water washed aluminum member with washing water are performed. The raw wastewater generated with the surface treatment method is treated.
The raw waste water is used as flush water discharged from the primary flush tank, the purified water is reused as flush water in the secondary flush tank, and the flush water discharged from the second flush tank is used as the primary flush water. The wastewater treatment method according to claim 7, wherein the wastewater treatment method is reused as flush water for the tank. The ion removal step includes a first ion removal step of allowing the acidic drainage to pass through a reverse osmosis membrane and discharging, and a second ion passage of the first purified water through an ion exchange resin to discharge as the purified water. The waste water treatment method according to any one of claims 7 to 9, further comprising an ion removal step. Waste water treatment method according to any one of claims 7 to 10 wherein the neutral region is pH6 than pH7 or less. The wastewater treatment method according to claim 8 or 9 , wherein the coating treatment is anodizing treatment or colored chemical conversion treatment, and the neutralizing agent is sodium hydroxide.

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