A process for treating organic wastewater from a circuit board

Abstract

The application discloses a kind of treatment processes of circuit board organic wastewater, it is related to the technical field of water treatment, the process is first to the pH of circuit board organic wastewater Pre-adjustment, then through ferrous sulfate reagent removal heavy metal, again through metal ion complexing reagent, twice aeration and ion exchange resin filtration, one step removes cyanide and complex, again using ammonia treatment liquid and microporous hydrophobic membrane removes ammonia nitrogen, finally through MBR membrane-biological reactor removes residual organic matter.It can improve the treatment rate of refractory pollutants in circuit board organic wastewater, water treatment effect is better, and the purification rate is higher.

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment, and in particular to a treatment process for organic wastewater from circuit boards. Background Art

[0002] Circuit boards are the supports for electronic components. Traditionally, these circuit boards are manufactured using a printed etch resist process to create the circuitry and layout, hence the name printed circuit board (PCB). The PCB manufacturing process generates cleaning wastewater, mixed wastewater, organic wastewater, and concentrated acid and alkali wastewater. Organic pollutants in this organic wastewater are complex, highly concentrated, and contain many refractory components, making it challenging to treat.

[0003] In the related art, a treatment process for organic wastewater is disclosed: step one, measuring the COD content in the organic wastewater; step two, adding an inorganic acid to the organic wastewater, then adding a surface promoter to carry out a contact activation reaction, and then simultaneously adding a complex breaker and an oxidant to carry out a strong oxidation reaction; step three, adding alkali to the wastewater after the strong oxidation reaction for neutralization and adjustment so that the pH value of the wastewater is 7.59.0; step four, adding a flocculant to the neutralized and adjusted wastewater for a flocculation reaction, and then performing sedimentation separation, and safely treating the sediment residue, and the supernatant can meet the discharge standards.

[0004] However, the production wastewater of circuit board companies often contains difficult-to-degrade pollutants such as heavy metal ions, cyanide, ammonia nitrogen, and complexes. The above treatment process is difficult to treat wastewater containing these difficult-to-degrade pollutants. Summary of the Invention

[0005] In order to improve the treatment rate of difficult-to-degrade pollutants in organic wastewater from circuit boards, the present application provides a treatment process for organic wastewater from circuit boards.

[0006] This application provides a treatment process for organic wastewater from circuit boards, which adopts the following technical solutions:

[0007] A process for treating organic wastewater from circuit boards, comprising the following steps:

[0008] Pre-conditioning: Adjust the pH of the organic wastewater from the circuit board to 1-3 to obtain pre-conditioned wastewater;

[0009] Heavy metal removal: transfer the pre-conditioned wastewater to the reaction tank, add ferrous sulfate reagent to the reaction tank, stir evenly, adjust the pH of the wastewater in the reaction tank to 8-9, precipitate until solid-liquid stratification, and after solid-liquid separation, obtain a primary supernatant and a primary solid waste;

[0010] Precision filtration: The pH of the primary supernatant is adjusted to 10.5-11.5, and then the primary supernatant is mixed with a metal ion complexing agent, and aerated for 1-2 hours to obtain primary aeration water. The pH of the primary aeration water is then adjusted to 7-8, and then the primary aeration water is mixed with a metal ion complexing agent, and aerated for another 1-2 hours to obtain secondary aeration water. The pH of the secondary aeration water is adjusted to 4-6, and the secondary aeration water is filtered using an ion exchange resin to obtain precision filtered water.

[0011] Ammonia nitrogen removal: The precision filtered water is transferred to the membrane reaction tank, and the ammonia treatment liquid is input into the membrane reaction tank. The membrane reaction tank is provided with a microporous hydrophobic membrane for separating the precision filtered water and the ammonia treatment liquid. The NH3 in the precision filtered water passes through the microporous hydrophobic membrane and reacts with the ammonia treatment liquid. After the reaction is completed, ammonia nitrogen-removed water is obtained;

[0012] Biochemical reaction: The ammonia nitrogen-removed water is transferred to the MBR membrane-bioreactor for biochemical reaction. After the biochemical reaction is completed, the water is filtered out, and the wastewater treatment is completed.

[0013] By adopting the above-mentioned technical scheme, the present application is adjusted to the pH value of waste water to highly acidic by pre-adjusting step, and heavy metal ions in waste water are helped to react with ferrous sulfate agent in heavy metal removal step, so that heavy metal ions generate precipitate, and are easy to remove heavy metal ions in waste water. In heavy metal removal step, the pH value of waste water is adjusted to 8-9, and heavy metal ions in heavy metal precipitation are helped to reduce and are dissolved in waste water again. By precise filtration step, cyanide in waste water can be first converted into complex compound, and then the complex compound in waste water is adsorbed by ion exchange resin, so that cyanide and complex compound in waste water are removed in one step. By microporous hydrophobic membrane, NH3 in waste water is made to pass through microporous hydrophobic membrane under the effect of concentration difference and react with ammonia treatment solution and generate ammonium salt solution, so as to remove ammonia nitrogen in waste water, finally by the microorganism in MBR membrane-bioreactor, waste water is carried out further biochemical reaction, organic matter in waste water is removed, the treatment rate of refractory pollutants in circuit board organic waste water can be improved, therefore, the treatment process water treatment effect of the present application is better, and purification rate is higher.

[0014] In a specific embodiment, in the pre-conditioning step, the circuit board organic wastewater is added to the regulating tank, and hydrochloric acid and / or sodium hydroxide is added to the regulating tank to adjust the pH of the wastewater in the regulating tank to 1-3.

[0015] By adopting the above technical solution, hydrochloric acid and / or sodium hydroxide can be selectively added according to the initial pH of the organic wastewater from the circuit board, thereby adjusting the pH of the wastewater to 1-3. Moreover, neither hydrochloric acid nor sodium hydroxide will introduce new difficult-to-degrade pollutants into the wastewater, and will not increase the difficulty of wastewater treatment.

[0016] In a specific embodiment, in the heavy metal removal step, the ferrous sulfate agent is an aqueous solution of ferrous sulfate with a concentration of 15-30 g / L, and the volume ratio of the pre-conditioned wastewater to the ferrous sulfate agent is 1:(0.3-0.7).

[0017] By adopting the above technical solution, the concentration of ferrous sulfate in the wastewater has an important influence on the removal rate of heavy metal ions. When the concentration of ferrous sulfate in the wastewater is too low, the removal rate of heavy metal ions in the wastewater is low. When the concentration of ferrous sulfate in the wastewater is too high, it will cause waste of ferrous sulfate reagent. The present application has found through experiments that when the concentration and dosage of ferrous sulfate are controlled within the above range, the removal rate of heavy metal ions in the wastewater is high, and the waste of ferrous sulfate reagent is also less.

[0018] In a specific embodiment, the metal ion complexing agent is zinc chloride.

[0019] By adopting the above technical solution, zinc chloride can remove the free CN in the wastewater. - Conversion to metal complexes, pH adjustment and aeration all contribute to the conversion of cyanide in wastewater into free CN - , which helps to improve the removal rate of cyanide.

[0020] In a specific embodiment, in the precision filtration step, the weight ratio of the primary supernatant to the metal ion complexing agent is 1:(0.3-0.8).

[0021] By adopting the above technical solution, the ratio of the primary supernatant to the metal ion complexing agent is controlled within the above range, which helps to increase the free CN in the primary supernatant. - The conversion rate of metal ion complexes can be increased, and the waste of metal ion complexing reagents can be reduced.

[0022] In a specific embodiment, in the precision filtration step, the weight ratio of the primary aeration water to the metal ion complexing agent is 1:(0.1-0.4).

[0023] By adopting the above technical solution, after pH adjustment and the first aeration, some free CN is generated in the aerated water. - , but compared with the primary supernatant, free CN - The content of CN is greatly reduced, so only a small amount of metal ion complexing reagent is needed to convert the free CN into - Regarding the conversion into metal complexes, it has been found through experiments that controlling the ratio of primary aeration water to metal ion complexing reagent within the above range can achieve better conversion effects.

[0024] In a specific embodiment, in the precision filtration step, the filtered ion exchange resin is eluted with a hydrochloric acid solution to recover the metals and metal compounds precipitated on the ion exchange resin.

[0025] By adopting the above technical solution, the hydrochloric acid solution can react with the metal complexes adsorbed on the ion exchange resin to recover recyclable metals and metal compounds, which helps save resources and reduce processing costs. Moreover, the ion exchange resin can be reused after elution.

[0026] In a specific embodiment, in the precision filtration step, the ion exchange resin is a brand 717 basic anion exchange resin or a 702 basic anion exchange resin.

[0027] By adopting the above technical solution and using the above-mentioned brand of alkaline anion exchange resin, a stronger adsorption effect is achieved for the complex in the wastewater of the present application, which can improve the removal rate of cyanide and the complex.

[0028] In summary, this application includes at least one of the following beneficial technical effects:

[0029] 1. The process of this application can improve the treatment rate of difficult-to-degrade pollutants in organic wastewater from circuit boards, with better water treatment effects and higher purification rates;

[0030] 2. The process of this application can remove cyanide and complexes in one step with a high removal rate;

[0031] 3. The process of this application can save resources and reduce costs. DETAILED DESCRIPTION

[0032] The present application is further described in detail below with reference to examples and comparative examples.

[0033] Example

[0034] Example 1

[0035] This embodiment provides a process for treating organic wastewater from circuit boards, which includes the following steps:

[0036] First, the pH of the wastewater is pre-adjusted as follows: the circuit board organic wastewater is input into the regulating tank, the initial pH of the circuit board organic wastewater is detected, and hydrochloric acid and / or sodium hydroxide are selectively added to the regulating tank according to the initial pH. During the addition of hydrochloric acid and / or sodium hydroxide, the wastewater in the regulating tank is continuously stirred, and the pH of the wastewater in the regulating tank is continuously detected. When the pH of the wastewater in the regulating tank is adjusted to 2, pre-adjusted wastewater is obtained.

[0037] The pre-conditioned wastewater is then treated to remove heavy metals in the pre-conditioned wastewater. The operation is as follows: the pre-conditioned wastewater is transferred to a reaction tank, and a ferrous sulfate agent with a concentration of 22 g / L is added to the reaction tank, wherein the volume ratio of the pre-conditioned wastewater to the ferrous sulfate agent is 1:0.5. After stirring evenly, hydrochloric acid and / or sodium hydroxide are added to the reaction tank, and the pH of the wastewater in the reaction tank is adjusted to between 8-9. After continuing to stir for 10 minutes, it is allowed to settle for 5 hours. The wastewater in the reaction tank undergoes solid-liquid stratification, and the wastewater in the reaction tank is subjected to solid-liquid separation to obtain a primary supernatant and a primary solid waste, and the primary solid waste is transported to a solid waste treatment unit for treatment.

[0038] The first supernatant is then subjected to precision filtration to remove cyanide and complexes in the first supernatant. The operation is as follows: the first supernatant is input into a precision filtration pool, hydrochloric acid and / or sodium hydroxide are added to the precision filtration pool, the pH of the wastewater in the precision filtration pool is adjusted to between 10.5 and 11.5, and then zinc chloride is added to the precision filtration pool. The weight ratio of the first supernatant to the metal ion complexing agent is 1:0.5. After stirring until uniform, aeration is performed for 1.5 hours to obtain aerated water, and hydrochloric acid and / or sodium hydroxide are added to the precision filtration pool. Sodium hydroxide is used to adjust the pH of the wastewater in the precision filtration pool to 7-8, and then zinc chloride is added to the precision filtration pool. The weight ratio of the primary aeration water to the metal ion complexing agent is 1:0.3. After stirring evenly, aeration is performed for 1.5 hours to obtain secondary aeration water. Then hydrochloric acid and / or sodium hydroxide are added to the precision filtration pool to adjust the pH of the wastewater in the precision filtration pool to between 4-6. The wastewater in the precision filtration pool is filtered using 717 alkaline anion exchange resin, and the filtered water is collected to obtain precision filtered water.

[0039] The precision filtered water is then subjected to membrane reaction treatment to remove ammonia nitrogen from the precision filtered water. The operation is as follows: the precision filtered water is transferred to a membrane reaction tank, which is provided with a microporous filtration membrane. The microporous filtration membrane separates the membrane reaction tank into two parts. The precision filtered water is located on one side of the microporous filtration membrane, and ammonia treatment liquid is input into the other side of the microporous filtration membrane. The ammonia treatment liquid is a sulfuric acid solution with a solute mass fraction of 15%. The free NH3 in the precision filtered water passes through the microporous hydrophobic membrane and reacts with H+ at the interface between the microporous hydrophobic membrane and the sulfuric acid solution. After 5 hours of reaction, the reaction is stopped to obtain ammonia nitrogen-removed water.

[0040] Then the ammonia nitrogen-removed water is subjected to a biochemical reaction as follows: the ammonia nitrogen-removed water is transferred to the MBR membrane-bioreactor. The activated sludge concentration in the MBR membrane-bioreactor is 10,000 mg / L, the hydraulic retention time is 15 hours, and the biochemical reaction is carried out. After the biochemical reaction is completed, the water is filtered out, and the wastewater treatment is completed.

[0041] Example 2

[0042] This embodiment provides a treatment process for organic wastewater from circuit boards. The only difference between this embodiment and Example 1 is that when the pH of the wastewater in the regulating tank is adjusted to 1, pre-regulated wastewater is obtained.

[0043] Example 3

[0044] This embodiment provides a treatment process for organic wastewater from circuit boards. The only difference between this embodiment and Example 1 is that when the pH of the wastewater in the regulating tank is adjusted to 3, pre-regulated wastewater is obtained.

[0045] Example 4

[0046] This embodiment provides a treatment process for organic wastewater from a circuit board. The only difference between this embodiment and Example 1 is that the pre-conditioned wastewater is transferred to a reaction tank, and ferrous sulfate with a concentration of 15 g / L is added to the reaction tank, wherein the volume ratio of the pre-conditioned wastewater to the ferrous sulfate is 1:0.7.

[0047] Example 5

[0048] This embodiment provides a treatment process for organic wastewater from a circuit board. The only difference between this embodiment and Example 1 is that the pre-conditioned wastewater is transferred to a reaction tank, and a ferrous sulfate agent with a concentration of 30 g / L is added to the reaction tank, wherein the volume ratio of the pre-conditioned wastewater to the ferrous sulfate agent is 1:0.3.

[0049] Example 6

[0050] This embodiment provides a treatment process for organic wastewater from circuit boards. The only difference between this embodiment and Example 1 is that the metal ion complexing agent is zinc sulfate.

[0051] Example 7

[0052] This embodiment provides a treatment process for organic wastewater from circuit boards. The only difference between this embodiment and Example 1 is that the metal ion complexing agent is sodium hypochlorite.

[0053] Example 8

[0054] This embodiment provides a treatment process for organic wastewater from circuit boards. The only difference between this embodiment and Example 1 is that the weight ratio of the primary supernatant to the metal ion complexing agent is 1:0.3. After stirring until uniform, aeration is performed for 1.5 hours to obtain primary aerated water.

[0055] Example 9

[0056] This embodiment provides a treatment process for organic wastewater from circuit boards. The only difference between this embodiment and Example 1 is that the weight ratio of the primary supernatant to the metal ion complexing agent is 1:0.8. After stirring until uniform, aeration is performed for 1.5 hours to obtain primary aerated water.

[0057] Example 10

[0058] This embodiment provides a treatment process for organic wastewater from circuit boards. The only difference between this embodiment and Example 1 is that the weight ratio of primary aeration water to metal ion complexing agent is 1:0.1. After stirring evenly, aeration is performed for 1.5 hours to obtain secondary aeration water.

[0059] Example 11

[0060] This embodiment provides a treatment process for organic wastewater from circuit boards. The only difference between this embodiment and Example 1 is that the weight ratio of primary aeration water to metal ion complexing agent is 1:0.4. After stirring evenly, aeration is performed for 1.5 hours to obtain secondary aeration water.

[0061] Example 12

[0062] This embodiment provides a treatment process for organic wastewater from circuit boards. The only difference between this embodiment and Example 1 is that the weight ratio of the primary supernatant to the metal ion complexing agent is 1:0.3. After stirring until uniform, aeration is performed for 1.5 hours to obtain primary aerated water. The weight ratio of the primary aerated water to the metal ion complexing agent is 1:0.4. After stirring until uniform, aeration is performed for another 1.5 hours to obtain secondary aerated water.

[0063] Example 13

[0064] This embodiment provides a treatment process for organic wastewater from circuit boards. The only difference between this embodiment and Example 1 is that 702 alkaline anion exchange resin is used instead of 717 alkaline anion exchange resin.

[0065] Example 14

[0066] This embodiment provides a process for treating organic wastewater from circuit boards. The only difference between this embodiment and Example 1 is that Rohm and Haas IRC748 ion exchange resin is used instead of 717 basic anion exchange resin.

[0067] Example 15

[0068] This embodiment provides a treatment process for organic wastewater from circuit boards. The only difference between this embodiment and Example 1 is that 717 alkaline anion exchange resin is used to filter the wastewater in the precision filtration tank, and the filtered water is collected to obtain precision filtered water. Then, the 717 alkaline anion exchange resin is removed, and the 717 alkaline anion exchange resin is eluted with a hydrochloric acid solution with a solute mass fraction of 15%. Zinc and zinc compounds are precipitated on the surface of the 717 alkaline anion exchange resin, and the zinc and zinc compounds are recovered.

[0069] Comparative Example

[0070] Comparative Example 1

[0071] This comparative example provides a treatment process for organic wastewater from a circuit board. The only difference between this comparative example and Example 1 is that the pre-conditioning step is not included, and the organic wastewater from the circuit board is directly input into the reaction tank. The volume ratio of the organic wastewater from the circuit board to the ferrous sulfate agent is 1:0.5.

[0072] Comparative Example 2

[0073] This comparative example provides a treatment process for organic wastewater from a circuit board. The only difference between this comparative example and Example 1 is that, in the step of performing precise filtration, the primary supernatant is input into a precise filtration pool, hydrochloric acid and / or sodium hydroxide are added to the precise filtration pool, and the pH of the wastewater in the precise filtration pool is adjusted to between 10.5-11.5, and then zinc chloride is added to the precise filtration pool, the weight ratio of the primary supernatant to the metal ion complexing agent is 1:0.8, and after stirring until uniform, hydrochloric acid and / or sodium hydroxide are added to the precise filtration pool, and the pH of the wastewater in the precise filtration pool is adjusted to between 4-6, and the wastewater in the precise filtration pool is filtered using 717 alkaline anion exchange resin, and the filtered water is collected to obtain precise filtered water.

[0074] Comparative Example 3

[0075] This comparative example provides a treatment process for organic wastewater from a circuit board. The only difference between this comparative example and Example 1 is that, in the step of performing precise filtration, the primary supernatant is input into a precise filtration pool, hydrochloric acid and / or sodium hydroxide are added to the precise filtration pool, and the pH of the wastewater in the precise filtration pool is adjusted to between 10.5-11.5, and then zinc chloride is added to the precise filtration pool, and the weight ratio of the primary supernatant to the metal ion complexing agent is 1:0.5. After stirring until uniform, hydrochloric acid and / or sodium hydroxide are added to the precise filtration pool, and the pH of the wastewater in the precise filtration pool is adjusted to 7-8, and then zinc chloride is added to the precise filtration pool, and the weight ratio of the wastewater in the precise filtration pool to the metal ion complexing agent is 1:0.3. After stirring evenly, hydrochloric acid and / or sodium hydroxide are added to the precise filtration pool, and the pH of the wastewater in the precise filtration pool is adjusted to between 4-6. The wastewater in the precise filtration pool is filtered using 717 alkaline anion exchange resin, and the filtered water is collected to obtain precise filtered water.

[0076] Comparative Example 4

[0077] This comparative example provides a treatment process for organic wastewater from a circuit board. The only difference between this comparative example and Example 1 is that, in the step of performing precision filtration, the primary supernatant is input into a precision filtration pool, hydrochloric acid and / or sodium hydroxide are added to the precision filtration pool, the pH of the wastewater in the precision filtration pool is adjusted to between 10.5 and 11.5, and then zinc chloride is added to the precision filtration pool. The weight ratio of the primary supernatant to the metal ion complexing agent is 1:0.5. After stirring until uniform, aeration is performed for 1.5 hours to obtain primary aerated water, which is then fed to the precision filtration pool. Add hydrochloric acid and / or sodium hydroxide to the precision filtration tank, adjust the pH of the wastewater in the precision filtration tank to 7-8, and then add zinc chloride to the precision filtration tank. The weight ratio of the primary aeration water to the metal ion complexing agent is 1:0.3. After stirring evenly, aerate for 1.5 hours to obtain secondary aeration water. Then add hydrochloric acid and / or sodium hydroxide to the precision filtration tank, adjust the pH of the wastewater in the precision filtration tank to between 4-6, and use an activated carbon layer to filter the wastewater in the precision filtration tank. Collect the filtered water to obtain precision filtered water.

[0078] Performance testing experiment

[0079] The effluent obtained by the process treatment of Examples 1-15 and Comparative Examples 1-4 was tested according to the first-level standards of GB7488-87, GB7479-87, GB11914-89, GB11901-89, and the Integrated Sewage Discharge Standard (GB8978-1996). The test results are shown in Table 1.

[0080] Table 1

[0081]

[0082]

[0083] Combining Example 1 and Comparative Examples 1-4 and Table 1, it can be seen that compared with Example 1, the COD in the effluent of Comparative Examples 1-4 is Cr , BOD5, NH3-N and SS are all large and greater than the standard values, which shows that the process conditions of Example 1 of the present application are helpful to improve the treatment rate of difficult-to-degrade pollutants in the organic wastewater of the circuit board.

[0084] Combining Examples 1-15 and Table 1, it can be seen that the COD in the effluent of Examples 1-15 is Cr , BOD5, NH3-N and SS are all lower than the standard values, which shows that the process conditions within the numerical range of Examples 1-15 are helpful to improve the treatment rate of difficult-to-degrade pollutants in the organic wastewater of circuit boards.

[0085] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A process for treating organic wastewater from circuit boards, characterized in that: The steps include: Pre-conditioning: Adjust the pH of the organic wastewater from the circuit board to 1-3 to obtain pre-conditioned wastewater; Heavy metal removal: transfer the pre-conditioned wastewater to the reaction tank, add ferrous sulfate reagent to the reaction tank, stir evenly, adjust the pH of the wastewater in the reaction tank to 8-9, precipitate until solid-liquid stratification, and after solid-liquid separation, obtain a primary supernatant and a primary solid waste; Precision filtration: adjusting the pH of the primary supernatant to 10.5-11.5, then mixing the primary supernatant with a metal ion complexing agent, aerating for 1-2 hours to obtain primary aeration water, then adjusting the pH of the primary aeration water to 7-8, then mixing the primary aeration water with a metal ion complexing agent, aerating for 1-2 hours to obtain secondary aeration water, adjusting the pH of the secondary aeration water to 4-6, and filtering the secondary aeration water with an ion exchange resin to obtain precision filtered water; in this step, the ion exchange resin is a 717 basic anion exchange resin or a 702 basic anion exchange resin; Ammonia nitrogen removal: The precision filtered water is transferred to the membrane reaction tank, and the ammonia treatment liquid is input into the membrane reaction tank. The membrane reaction tank is provided with a microporous hydrophobic membrane for separating the precision filtered water and the ammonia treatment liquid. The NH3 in the precision filtered water passes through the microporous hydrophobic membrane and reacts with the ammonia treatment liquid. After the reaction is completed, ammonia nitrogen-removed water is obtained; Biochemical reaction: The ammonia nitrogen-removed water is transferred to the MBR membrane-bioreactor for biochemical reaction. After the biochemical reaction is completed, the water is filtered out, and the wastewater treatment is completed.

2. The process for treating organic wastewater from a circuit board according to claim 1, characterized in that: In the pre-regulation step, the circuit board organic wastewater is added to the regulating tank, and hydrochloric acid and / or sodium hydroxide is added to the regulating tank to adjust the pH of the wastewater in the regulating tank to 1-3.

3. The process for treating organic wastewater from a circuit board according to claim 1, characterized in that: In the heavy metal removal step, the ferrous sulfate agent is a ferrous sulfate aqueous solution with a concentration of 15-30 g / L, and the volume ratio of the pre-conditioned wastewater to the ferrous sulfate agent is 1:(0.3-0.7).

4. The process for treating organic wastewater from a circuit board according to claim 1, characterized in that: The metal ion complexing agent is zinc chloride.

5. The process for treating organic wastewater from a circuit board according to claim 4, characterized in that: In the precision filtration step, the weight ratio of the primary supernatant to the metal ion complexing agent is 1:(0.3-0.8).

6. The process for treating organic wastewater from a circuit board according to claim 5, characterized in that: In the precision filtration step, the weight ratio of the primary aeration water to the metal ion complexing agent is 1:(0.1-0.4).

7. The process for treating organic wastewater from a circuit board according to claim 1, characterized in that: In the precision filtration step, the filtered ion exchange resin is eluted with a hydrochloric acid solution to recover the metals and metal compounds precipitated on the ion exchange resin.

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