阅读说明：本技术 电镀尾水无害化处理的方法 (Method for harmless treatment of electroplating tail water ) 是由 叶树勤 郭升彬 苏孝缘 陈李鑫 杨伟杰 于 2021-07-30 设计创作，主要内容包括：本发明涉及一种电镀尾水无害化处理的方法,包括如下步骤：S01.完成前处理的电镀尾水进行二级芬顿氧化处理,进行固液分离后得溶液A；S02.将溶液A进行二级生化处理,进行固液分离后得到溶液B；S03.将溶液B进行一级芬顿氧化处理,进行固液分离后得到溶液C；S04.将溶液C进行漂水混凝沉淀处理,进行固液分离后得到溶液D；S05.检测溶液D中的总铜含量、总镍含量、COD含量、氨氮含量、硝酸盐氮含量、亚硝酸盐氮含量、总氮含量、总磷含量、有机氮含量以及电导率。(The invention relates to a method for innocent treatment of electroplating tail water, which comprises the following steps: s01, performing secondary Fenton oxidation treatment on the electroplating tail water after pretreatment, and performing solid-liquid separation to obtain a solution A; s02, performing secondary biochemical treatment on the solution A, and performing solid-liquid separation to obtain a solution B; s03, performing primary Fenton oxidation treatment on the solution B, and performing solid-liquid separation to obtain a solution C; s04, carrying out bleaching water coagulation precipitation treatment on the solution C, and carrying out solid-liquid separation to obtain a solution D; and S05, detecting the total copper content, the total nickel content, the COD content, the ammonia nitrogen content, the nitrate nitrogen content, the nitrite nitrogen content, the total phosphorus content, the organic nitrogen content and the conductivity in the solution D.)

1. A method for harmless treatment of electroplating tail water is characterized by comprising the following steps:

s01, performing secondary Fenton oxidation treatment on the electroplating tail water subjected to pretreatment, and performing solid-liquid separation to obtain a solution A;

s02, performing secondary biochemical treatment on the solution A, and performing solid-liquid separation to obtain a solution B;

s03, performing primary Fenton oxidation treatment on the solution B, and performing solid-liquid separation to obtain a solution C;

s04, carrying out bleaching water coagulation precipitation treatment on the solution C, and carrying out solid-liquid separation to obtain a solution D;

and S05, detecting the total copper content, the total nickel content, the COD content, the ammonia nitrogen content, the nitrate nitrogen content, the nitrite nitrogen content, the total phosphorus content, the organic nitrogen content and the conductivity in the solution D.

2. The method according to claim 1, wherein the rinsing water coagulating sedimentation treatment is specifically: and mixing the solution C with a bleaching aqueous solution, standing, and then carrying out solid-liquid separation, wherein the mass fraction of sodium hypochlorite in the bleaching aqueous solution is 9.0-11.0%.

Technical Field

The invention relates to the field of electroplating wastewater treatment, in particular to a method for harmlessly treating electroplating tail water.

Background

The electroplating industry is one of three global pollution industries, and biochemical tail water generated by electroplating contains cyanide, organic pollutants, and various heavy metal ions such as copper, nickel, zinc, chromium and the like. With increasingly strict environmental protection standards of China, the discharge of electroplating tail water in part of regions is required to reach the standards (nickel content is less than or equal to 0.1mg/L and total nitrogen content is less than or equal to 15mg/L) specified in the discharge Standard of electroplating pollutants (GB 21900-2008). The prior technical scheme for treating the electroplating tail water adopts multi-stage Fenton oxidation and combines an activated sludge method to remove heavy metals and organic pollutants in the electroplating tail water, but the technical problem of the prior technical scheme is that after the electroplating tail water is treated by the prior technical scheme, the nickel content in the electroplating tail water is still not reduced to be below 0.1mg/L because the nickel in the electroplating tail water exists in a complex state; the electroplating tail water contains a large amount of organic nitrogen substances which are difficult to degrade, and the organic nitrogen substances cannot be effectively decomposed and removed by the conventional treatment process, so that the total nitrogen in the finally discharged water cannot be reduced to 15 mg/L.

Description of the terms

The specific steps of the Fenton oxidation treatment described in the present invention are: s1, adding 50% sulfuric acid into a solution to be treated, and adjusting the pH value of the solution to be treated to 3.0; s2, adding 1.2kg of ferrous and 0.8kg of 30% hydrogen peroxide into each water, and performing Fenton reaction for 4 hours; s3, adding a calcium hydroxide solution to adjust the pH value of the solution to 8.5, adding a 30% liquid caustic soda solution to adjust the pH value of the solution to 10.5, continuing to react for 1 hour, and adding a pam solution during the reaction; s4, standing and precipitating after complete reaction, then carrying out solid-liquid separation, carrying out other treatments on the separated solution, carrying out filter pressing on the separated solid sludge, and entrusting the filter-pressed dry sludge to a special enterprise for sludge treatment.

The first-stage Fenton oxidation treatment is defined as that the solution to be treated is subjected to primary Fenton oxidation treatment; the "second-stage Fenton oxidation treatment" described in the present invention is defined as subjecting a solution to be treated to two Fenton oxidation treatments.

The "plating tail water" described in the present invention includes high-concentration wastewater, Ro concentrate, and press filtration water.

The "plating tail water after completion of pretreatment" described in the present invention is defined as "plating tail water after completion of pretreatment" obtained by subjecting high-concentration wastewater to secondary fenton oxidation treatment, subjecting Ro concentrated water to primary fenton oxidation treatment, subjecting filter pressing water to coagulation precipitation treatment in a coagulation precipitation tank, and mixing the obtained liquids uniformly.

The inventionThe term "biochemical treatment" as used herein is defined as the treatment of a solution to be treated sequentially in a hydrolysis acidification tank, an anaerobic tank, an anoxic tank, an aerobic tank, a deoxidation tank and a sedimentation tank, and the biochemical treatment is defined in the present invention as follows: the amount of the solution treated by biochemical treatment is not more than 3000m per 24h³And the dissolved oxygen in the aerobic tank is not less than 3.0 mg/L. The specific treatment technical scheme in the hydrolysis acidification tank, the anaerobic tank, the anoxic tank, the aerobic tank, the deoxidation tank and the sedimentation tank can adopt the technical scheme disclosed in the prior art, such as a system for treating wastewater and a treatment process of the system, which are composed of the hydrolysis acidification tank, the pre-anoxic tank, the anaerobic tank, the anoxic tank and the aerobic tank disclosed in the chinese patent application 201510669834.6, such as the anaerobic tank, the anoxic tank and the deoxidation tank disclosed in the chinese patent application 201420432848.7, and such as the sedimentation tank disclosed in the chinese patent application 201610447942.3 (equivalent to the sedimentation tank in the present invention). In the invention, the solution is subjected to a coagulating sedimentation method in a sedimentation tank, namely, sodium hydroxide or lime milk is added into the solution to adjust the pH value to be alkaline, then flocculants such as PAC, PAM and the like and coagulants are added, the solution is stood, then solid-liquid separation is carried out, other treatments are carried out on the supernatant to remove organic pollutants, the lower layer of solid sludge is discharged and then filter-pressed, and the filter-pressed dry sludge is entrusted to a special enterprise to carry out sludge treatment.

The "secondary biochemical treatment" described in the present invention is defined as subjecting a solution to be treated to two biochemical treatments.

Disclosure of Invention

Aiming at the technical problems in the prior art, the invention provides a method for harmlessly treating electroplating tail water, and the electroplating tail water treated by the method can meet the requirements specified in the discharge Standard of electroplating pollutants (GB 21900-2008).

In order to achieve the purpose, the invention adopts the following technical scheme: a method for harmless treatment of electroplating tail water comprises the following steps: and (4) sequentially carrying out secondary Fenton oxidation treatment, secondary biochemical treatment, primary Fenton oxidation treatment and bleaching water coagulating sedimentation treatment on the electroplating tail water after the pretreatment is finished.

Wherein, the treatment of the floating water coagulating sedimentation is as follows: mixing the solution to be treated and the bleaching aqueous solution, standing, then carrying out solid-liquid separation, discharging supernatant liquid after meeting the discharge standard, carrying out filter pressing after discharging lower-layer solid sludge, and entrusting the filter-pressed dry sludge to a special enterprise for sludge treatment. The bleaching aqueous solution contains sodium hypochlorite solution, and the mass fraction of the sodium hypochlorite in the bleaching aqueous solution is 9.0-11.0%.

Compared with the prior art, the technical scheme of the invention has the following beneficial effects:

1. the method provided by the invention is suitable for treating the electroplating tail water after the pretreatment is finished, and from the view of terminal water quality test data, the complex nickel ions and most of organic nitrogen substances in the electroplating tail water treated by the method are removed, so that the requirements specified in the discharge standard of electroplating pollutants (GB 21900-2008) can be met, and the method has a better removal effect on total nitrogen and total nickel indexes in the electroplating tail water compared with the prior art;

2. after the electroplating tail water is treated by the method provided by the invention, the concentration content of various pollutants in the water is lower than the value specified in the discharge standard of electroplating pollutants (GB 21900-2008), even the concentration of partial pollutants is very close to zero, so that the improvement of the effect of treating the electroplating tail water by adding the treatment process on the basis of the method provided by the invention is not obvious or even almost has no influence, and the cost can be obviously improved by adding the treatment process;

3. the inventor unexpectedly finds that if the sequence of the steps of the method provided by the invention is changed, the terminal water quality can not meet the requirements specified in the discharge standard of electroplating pollutants (GB 21900-2008); the inventor unexpectedly finds that the method provided by the invention can cause the terminal water quality to not meet the requirements regulated in the discharge Standard of electroplating pollutants (GB 21900-2008) if single or multiple steps in the method are reduced or replaced; therefore, the method provided by the invention achieves the best effect and cost on treating the electroplating tail water.

The following description will be given with reference to specific examples.

Drawings

The figures further illustrate the invention, but the examples in the figures do not constitute any limitation of the invention.

Fig. 1 is a flowchart of a method for harmless treatment of electroplating tail water according to an embodiment of the present invention.

Detailed Description

It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Example 1

As shown in fig. 1, the present embodiment provides a method for harmless treatment of electroplating tail water, which specifically includes the following steps:

s01, performing secondary Fenton oxidation treatment on the electroplating tail water after pretreatment, and performing solid-liquid separation to obtain a solution A;

s02, performing secondary biochemical treatment on the solution A, and performing solid-liquid separation to obtain a solution B;

s03, performing primary Fenton oxidation treatment on the solution B, and performing solid-liquid separation to obtain a solution C;

s04, carrying out bleaching water coagulation precipitation treatment on the solution C, and carrying out solid-liquid separation to obtain a solution D;

s05, detecting the solution D, analyzing whether the pH, total copper, total nickel, COD, ammonia nitrogen, nitrate nitrogen, nitrite nitrogen, total phosphorus, organic nitrogen and conductivity indexes in the solution D meet the requirements specified in the discharge Standard of electroplating pollutants (GB 21900-2008) or not by data, and discharging the solution D if the requirements are met; if the requirement is not met, the solution D is repeatedly subjected to a harmless treatment process until the solution D reaches the discharge standard.

In the method for harmless treatment of electroplating tail water provided in this embodiment, the inventors found that the steps included in the method cannot be reduced or replaced, and the sequence of the steps included in the method cannot be changed, otherwise the finally obtained water quality cannot meet the requirements specified in "emission standard of electroplating pollutants" (GB 21900-2008), and the inventors are not clear of the principle, but the inventors guess the reason for the reason as follows: 1. the bleaching water solution (containing 9.0-11.0% by mass of sodium hypochlorite) used in the coagulation and precipitation treatment of the bleaching water is a strong oxidant, is commonly used for sterilization, bleaching, nitrogen removal and the like in wastewater treatment, although the oxidation of the bleaching water is not as good as that of Fenton oxidation and ozone oxidation, factors such as the particularity of pollutants in electroplating tail water, different selectivity of various oxidation technologies on pollutant removal, good and bad effects and the like are considered, so that the coagulation and precipitation treatment, the Fenton oxidation treatment and the biochemical treatment of the bleaching water have synergistic effect, and the treatment effect on the electroplating tail water is improved; 2. the previous step in the method has an influence on the next step, and the influence is finally reflected in the terminal water quality like a chain reaction, for example, after the electroplating tail water is subjected to the secondary Fenton oxidation treatment, part of organic compounds in the electroplating tail water can be oxidized into inorganic states, so that the content of part of organic compounds in the electroplating tail water is reduced, the treatment effect of the next secondary biochemical treatment on the electroplating tail water is improved, if the content of part of organic compounds in the electroplating tail water is not reduced (for example, the secondary Fenton oxidation treatment is not carried out) or is not reduced to a sufficiently low content (for example, the secondary Fenton oxidation treatment is replaced by the primary Fenton oxidation treatment or other treatment methods), the treatment effect of the next secondary biochemical treatment on the electroplating tail water is reduced, and the treatment effect of the next rinsing water coagulation precipitation treatment on the electroplating tail water is further reduced, until the terminal water quality is influenced and the discharge standard can not be met.

The change of the water quality before and after the treatment is shown in table 1 by comparing the method for harmless treatment of the electroplating tail water provided by the embodiment to treat the electroplating tail water after the pretreatment with the method for treating the electroplating tail water by using the prior technical scheme. The results in table 1 show that the terminal water quality obtained after the electroplating tail water is treated by the prior art does not meet the requirements specified in the discharge standard of electroplating pollutants (GB 21900-2008), while the terminal water quality obtained after the electroplating tail water is treated by the method provided in this example meets the requirements for discharge.

TABLE 1 Change in Water quality before and after treatment

Comparative example 1

This example provides a method for detoxifying plating tail water, and comparative example 1 differs from example 1 only in that step S01 is not provided.

Comparative example 2

This example provides a method for detoxifying plating tail water, and comparative example 2 differs from example 1 only in that step S02 is not provided.

Comparative example 3

This example provides a method for detoxifying plating tail water, and comparative example 3 differs from example 1 only in that step S03 is not provided.

Comparative example 4

This example provides a method for detoxifying plating tail water, and comparative example 4 differs from example 1 only in that the coagulation sedimentation treatment of the rinsing water in step S04 is replaced with a primary fenton oxidation treatment.

Comparative example 5

This example provides a method for detoxifying plating tail water, and comparative example 5 differs from example 1 only in that the secondary fenton oxidation treatment in step S01 is replaced with the primary fenton oxidation treatment, and the primary fenton oxidation treatment in step S03 is replaced with the secondary fenton oxidation treatment.

Comparative example 6

This example provides a method for detoxifying plating tail water, and comparative example 6 differs from example 1 only in that the secondary fenton oxidation treatment in step S01 is replaced with the secondary biochemical treatment, and the secondary biochemical treatment in step S02 is replaced with the secondary fenton oxidation treatment.

Comparative test

The plating tail water after the pretreatment was divided into 7 parts of the same volume, and treated by the methods provided in example 1 and comparative examples 1 to 6, respectively, and the water quality before and after the treatment was tested for pH, total copper, total nickel, COD, ammonia nitrogen, nitrate nitrogen, nitrite nitrogen, total nitrogen, and total phosphorus. Organic nitrogen and conductivity index, the test results are shown in table 2.

As can be seen from the results shown in Table 2, the water quality obtained by treating the pretreated plating tail water by the method provided by the invention meets the requirements (nickel content is less than or equal to 0.1mg/L and total nitrogen content is less than or equal to 15mg/L) specified in the discharge Standard for plating pollutants (GB 21900-2008), while the water quality obtained by treating the plating tail water by the method provided by the invention can not meet the requirements specified in the discharge Standard for plating pollutants (GB 21900-2008) if the steps included in the method provided by the invention are reduced (comparative example 1-3) or replaced (comparative example 4) or the sequence of the steps included in the method provided by the invention is changed (comparative example 5-6).

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

TABLE 2 Change in Water quality before and after treatment