CN205328814U - Handle alkaline dye wastewater's device - Google Patents

Abstract

The utility model discloses a handle alkaline dye wastewater's device, include the coagulating sedimentation tank, micro electrolytic reactor, flocculation and precipitation pond, MVR evaporimeter, the biochemical pond of AO and the electric catalytic oxidation device that connect gradually through the pipeline, coagulating sedimentation tank's import and alkaline dye wastewater access connection, the export and the waste water discharge port of electric catalytic oxidation device are connected, two electrodes of electricity catalytic oxidation device are metal electrode, and current density is 2mAcm2~20mAcm2. The utility model discloses in the multiple wastewater treatment process that combines, carry out the advanced treatment to alkaline dye wastewater for waste water COD after handling 50mgL, colourity 10, ensure that final exhaust waste water reaches national emission standard, simultaneously the utility model discloses in wastewater treating processes, the intermediate of production can retrieve and recycle, has reduced the waste water treatment cost, alleviates enterprise economy pressure.

Description

A device for treating basic dye wastewater

technical field

The utility model relates to a wastewater treatment process, in particular to a device for treating dye wastewater with high salt content and high COD that is difficult to biochemically degrade.

Background technique

While the printing and dyeing industry continues to develop, the water around the printing and dyeing factory is also polluted. This kind of wastewater has high chroma, high COD, and high salt content, which is difficult to treat with traditional biochemical methods. If this kind of wastewater is discharged directly into nature without treatment, it will pollute the water source and easily kill microorganisms, which will eventually endanger human health.

At present, the main methods for the treatment of dye sewage are as follows: Adsorption method: The most commonly used activated carbon method is to adsorb some insoluble and insoluble organic substances and organic substances with chromophores through a large number of pore walls on activated carbon. Flocculation method: Flocculation is also a common treatment method, and many organic wastewater can get good water effluent effect by flocculation. Biological method: Biological method is an ideal means to use microbial metabolism to realize the reduction and harmlessness of pollutants, and can effectively remove COD in sewage. Chemical oxidation method: chemical oxidation method includes Fenton method, hydrogen peroxide oxidation method, etc.

However, the above wastewater treatment methods still have relatively large deficiencies, especially for the treatment of basic dye wastewater in the printing and dyeing industry. The wastewater treated by traditional wastewater treatment methods is difficult to reach the standard of direct discharge. For example, the adsorption capacity of the adsorption method is relatively simple, and the chroma and COD removal of the more complex direct dye mother liquor wastewater are less than 10%, and the effect is not good; the flocculation method requires a large amount of flocculant and generates a large amount of solid waste. It is not suitable for large-scale use; the biological method takes a long time to take effect, microorganisms are sensitive to living conditions, and the water quality of dye wastewater is not stable enough; the chemical oxidation method cannot treat wastewater thoroughly, uses too many chemical raw materials, and the cost of the enterprise is too high.

Contents of the invention

Purpose of the invention: The purpose of this utility model is to address the deficiencies of the prior art, to provide a treatment device for alkaline dye wastewater with high salt content and difficult biodegradation in the printing and dyeing industry, which combines various wastewater treatment processes, and ensures that the discharged wastewater reaches While meeting the relevant national direct discharge standards, it reduces the cost of wastewater treatment for enterprises.

Technical solution: The device for treating alkaline dye wastewater described in the utility model includes coagulation sedimentation tanks, micro-electrolysis reactors, flocculation sedimentation tanks, MVR evaporators, A/O biochemical tanks and electrocatalytic oxidation devices connected in sequence through pipelines , the inlet of the coagulation sedimentation tank is connected with the basic dye wastewater inlet, and the outlet of the electrocatalytic oxidation device is connected with the wastewater outlet; the two electrodes of the electrocatalytic oxidation device are metal electrodes, and the current density is 2mA/cm ² ~20 mA/cm ² .

A further preferred technical solution of the utility model is that the anode of the electrocatalytic oxidation device is a titanium-based modified tin-antimony electrode, doped with one or more of cerium nitrate, bismuth nitrate, and PTFE, and the cathode is an electrode with the same area as the anode. Stainless steel.

Preferably, the micro-electrolysis reactor is composed of one or more stages of micro-electrolysis devices in series, and an aeration device is provided at the bottom of each stage of the micro-electrolysis devices.

The method for applying above-mentioned device to process basic dye wastewater in the utility model comprises the following steps:

(1) Pretreatment: Discharge the basic dye wastewater into the coagulation sedimentation tank, and add decolorization coagulant to the coagulation sedimentation tank for pre-decolorization treatment; the chromaticity of the water sample after the decolorization agent treatment is much lower than that of the raw water, which is convenient In the subsequent treatment process, the NaCl salt with better quality is recovered. In addition, the micelles generated during the flocculation process can effectively absorb some suspended small particles in the wastewater and reduce the COD of the wastewater;

(2) Micro-electrolysis: The pretreated wastewater is discharged into the micro-electrolysis reactor, and the iron-carbon micro-electrolysis filler that has been calcined at high temperature is added to the micro-electrolysis reactor. The substances generated during the micro-electrolysis process have high activity. Under acidic conditions, the new ecological H produced by the reaction can undergo oxidation-reduction reactions with the substances in the wastewater, destroying the original chromophoric groups in the wastewater, causing chain breakage of long-chain substances, and finally achieving the decolorization effect. The process will decompose part of the macromolecular substances in the wastewater into small molecular substances, and the COD of the wastewater can be reduced. Concentrated sulfuric acid is needed to adjust the pH during the reaction process, the pH value of the wastewater is controlled to be 3~5, the gas-water ratio is 1:3~1:5, and the hydraulic retention time is 60~100min;

(3) Flocculation and precipitation: Fe ³⁺ and Fe ²⁺ generated in the micro-electrolysis process are hydrolyzed and polymerized to form Fe(OH) ₃ and Fe(OH) ₂ in the form of colloids. These two substances have precipitation, Flocculation and adsorption, flocculation and precipitation together with pollutants in the wastewater, so that the organic matter in the wastewater is removed, and the wastewater treated by micro-electrolysis is discharged into the flocculation sedimentation tank, and the pH value of the wastewater in the tank is adjusted to 8~10. Exposure After 30 minutes of gas treatment, part of the organic matter in the wastewater will be removed along with the generated precipitate, and the supernatant will enter the MVR evaporator for subsequent treatment;

(4) MVR evaporation: filter the wastewater treated in step (3), and then evaporate it to separate the salt in the waste liquid; the operating cost of the MVR evaporator is low, and the energy consumption for evaporating one ton of water is about 1/6 to 1/5 of the traditional evaporator. The normal operation of the MVR evaporator can be made by replacing the traditional steam boiler with electricity, and the emission of SO ₂ , CO ₂ , dust and solid waste is reduced during the production process, and the harm to the environment is small. Put the water sample treated in step (3) into the evaporator for treatment, and the NaCl salt in the wastewater is separated to obtain white NaCl salt. Part of the mother liquor must be reused, and the evaporated liquid is subjected to subsequent treatment;

(5) A/O process: biochemically treat the wastewater treated in step (5), hydrolyze the macromolecular organic matter in the wastewater into small molecular organic matter, and reduce the COD and ammonia oxygen content of the wastewater; Nitrogen and phosphorus removal, while the O-stage process is mainly used to degrade organic matter in water. This process section performs biochemical treatment on the wastewater treated in step (4), and hydrolyzes the macromolecular organic matter in the wastewater into small molecular organic matter. The A/O process is adopted to reduce the COD of wastewater and effectively reduce the ammonia nitrogen content in wastewater;

(6) Electrocatalytic oxidation: Put the biochemically treated wastewater into the electrocatalytic oxidation device for electrocatalytic oxidation reaction, generate oxidized substances on the surface of the electrode, and deeply treat impurities in the wastewater. The COD removal rate reaches 99.8%, and finally discharged Wastewater, in the electrocatalytic reaction process, does not need to add chemical reagents, which can effectively avoid the generation of secondary pollution. The equipment in the whole process section is relatively simple and easy to automatically control. The biochemically treated wastewater is put into the electrocatalytic oxidation device for electrocatalysis The oxidation reaction generates some strong oxidizing substances on the surface of the electrode, and these strengthening substances can effectively degrade the organic matter that has not been treated by the A/O process.

Preferably, the anode of the electrocatalytic oxidation device described in step (6) is a titanium-based modified tin-antimony electrode, doped with one or more of cerium nitrate, bismuth nitrate, and PTFE, and the cathode is stainless steel with the same area as the anode; The current density is 2mA/cm ² ~20mA/cm ² , and the hydraulic retention time is 30-60min.

Preferably, the micro-electrolysis reactor described in step (2) is composed of one or more stages of micro-electrolysis devices connected in series, and the bottom of each stage of the micro-electrolysis devices is provided with an aeration device, and during the micro-electrolysis process, the solution is Concentrated H ₂ SO ₄ is added in the mid-term to maintain the pH value of the wastewater at 3~5, the gas-water ratio at 1:3~1:5, and the hydraulic retention time at 60~100min.

The device and method for processing basic dye wastewater in the present invention, the principles applied include:

Micro-electrolysis technology does not require an external electric field to energize. When the wastewater in the reactor remains acidic, Fe in the micro-electrolysis filler acts as the anode and C as the cathode, which will form countless small primary batteries by itself, and the organic matter in the wastewater will be discharged through the primary battery. Reactions such as ring opening and chain scission occur.

MVR evaporation is used to concentrate saline wastewater, recover the salt in it, reuse the mother liquor, and carry out subsequent treatment of the evaporated liquid.

Electrocatalytic oxidation mainly refers to the generation of a series of strong oxidizing substances (such as ?OH, O ₂ ^- , HO ₂ ^- , ROO ^- , etc.) degradation.

The above principles have been applied in the field of waste water treatment, but in this utility model, the key point to be solved is how to effectively combine several waste water treatment processes, while ensuring that the discharged waste water meets the relevant national direct discharge standards, and reduce the waste water of enterprises. Processing costs.

The concrete work process of the present utility model is described in detail below:

First of all, the pH of the dye wastewater is alkaline, so it is more suitable for pre-decolorization treatment with a decolorization coagulant. The decolorization coagulant can be directly added to the basic dye wastewater for pre-decolorization, and the water sample after decolorization and flocculation is discharged into the micro In the electrolytic reactor;

In the micro-electrolysis process, one-stage or multi-stage micro-electrolysis devices are used in series to treat wastewater. The effluent from the upper-stage micro-electrolysis device enters the next stage through gravity overflow to continue the reaction. During the reaction, the acid is adjusted to control the reaction. The pH of the wastewater in the device is between 3-5, so that the micro-electrolysis reaction can proceed smoothly;

After the micro-electrolysis reaction, the Fe ³⁺ and Fe ²⁺ produced in the micro-electrolysis process are hydrolyzed and polymerized to form Fe(OH) ₃ and Fe(OH) ₂ in the form of colloids. These two substances have precipitation, Flocculation and adsorption, flocculation with pollutants to produce precipitation, and finally the organic matter in the wastewater is removed;

The wastewater after flocculation and sedimentation contains a large amount of salt. If these salts are not concentrated and taken out, the wastewater cannot be subjected to subsequent biochemical advanced treatment; at the same time, after the front-end pre-decolorization treatment, the color of the wastewater is greatly reduced, and the evaporated salt can be continued Reuse to production to save cost;

In the A/O process, through the A-stage process, the macromolecular organic matter is hydrolyzed into small molecular organic matter, which improves the biodegradability of the wastewater, and through the O-stage process, the wastewater can be further treated;

There are still a small number of difficult-to-treat substances in the biochemical effluent. Finally, the wastewater is electrocatalytically oxidized for advanced treatment, and finally the wastewater is discharged up to the standard. The OH produced by the electrocatalytic oxidation reaction has an electrode potential of 2.8V (), which can be compared with large Part of the organic matter reacts to convert the organic matter that is difficult to treat by biochemical methods into small molecular substances, and can directly oxidize part of the organic matter into H ₂ O- and CO ₂ , reducing the COD of the effluent, and the treatment effect is good.

Beneficial effects: (1) The utility model organically combines a variety of wastewater treatment processes to carry out advanced treatment of basic dye wastewater, so that the COD of the wastewater is <50mg/L and the chroma is <10, ensuring that the final discharged wastewater meets the national discharge standard ; At the same time, the utility model saves intermediate additives and recycles intermediate products during the treatment process, which can relieve the waste water treatment cost and reduce the economic pressure of enterprises;

(2) Since electrocatalytic oxidation can selectively decompose the refractory substances in wastewater into carbon dioxide, water and minerals, the electron transfer only occurs between the surface of the titanium-based tin-antimony electrode and the wastewater during the treatment process, relying on the reaction process The generated strong oxidizing substances --- hydroxyl radicals, etc. oxidize organic matter, without adding liquid medicine, and no secondary pollution occurs; organic matter can be rapidly degraded during the reaction process, and the hydraulic retention time is short (30-60min) , the required equipment is small in size; the reaction requires mild conditions and can be carried out at normal temperature and pressure, the operation is simple and flexible, and the reaction conditions can be changed at any time by changing the voltage and current density, which is easy to operate; the titanium-based tin-antimony electrode is used , the electrode does not have corrosion and passivation problems, and has the characteristics of high efficiency and long life. The utility model adopts electrocatalytic oxidation to carry out advanced treatment of wastewater, and has strong impact resistance. The water quality is stable, the method is simple to operate and the operation cost is low, and has good economic and social benefits.

Description of drawings

Fig. 1 is the structural representation of the device for processing basic dye wastewater described in the utility model;

Fig. 2 is a waste water treatment flow chart of the device for treating basic dye waste water according to the utility model.

detailed description

The technical solutions of the present invention will be described in detail below with reference to the accompanying drawings, but the protection scope of the present invention is not limited to the embodiments.

Embodiment: a kind of device for processing basic dye waste water, comprises the coagulation-sedimentation tank, micro-electrolysis reactor, flocculation-settling tank, MVR evaporator, A/O biochemical pool and electrocatalytic oxidation device connected successively by pipeline, described The inlet of the coagulation sedimentation tank is connected with the inlet of basic dye wastewater, and the outlet of the electrocatalytic oxidation device is connected with the outlet of wastewater.

The anode of the electrocatalytic oxidation device is a titanium-based modified tin-antimony electrode doped with one or more of cerium nitrate, bismuth nitrate and PTFE, and the cathode is stainless steel with the same area as the anode.

The micro-electrolysis reactor is composed of one or more stages of micro-electrolysis devices connected in series, and the bottom of each stage of the micro-electrolysis devices is provided with an aeration device.

A method for applying the device to treat basic dye wastewater, comprising the steps of:

(1) Pretreatment: discharge the alkaline dye wastewater into the coagulation sedimentation tank, and add a decolorizing coagulant into the coagulation sedimentation tank for pre-decolorization treatment. In the subsequent treatment process, the NaCl salt with better quality is recovered. In addition, the micelles generated during the flocculation process can effectively absorb some suspended small particles in the wastewater and reduce the COD of the wastewater;

(2) Micro-electrolysis: The pretreated wastewater is discharged into the micro-electrolysis reactor, and the iron-carbon micro-electrolysis filler that has been calcined at high temperature is added to the micro-electrolysis reactor. The substances generated during the micro-electrolysis process have high activity. Under acidic conditions, the new ecological H produced by the reaction can undergo oxidation-reduction reactions with the substances in the wastewater, destroying the original chromophoric groups in the wastewater, causing chain breakage of long-chain substances, and finally achieving the decolorization effect. The process will decompose part of the macromolecular substances in the wastewater into small molecular substances, and the COD of the wastewater can be reduced. During the reaction process, it is necessary to use concentrated sulfuric acid to adjust the pH. The pH value of the wastewater is controlled to be 3~5, the gas-water ratio is 1:3~1:5, and the hydraulic retention time is 60~100min.

(3) Flocculation and precipitation: Fe ³⁺ and Fe ²⁺ generated in the micro-electrolysis process are hydrolyzed and polymerized to form Fe(OH) ₃ and Fe(OH) ₂ in the form of colloids. These two substances have precipitation, Flocculation and adsorption, flocculation and precipitation together with pollutants in the wastewater, so that the organic matter in the wastewater is removed, and the wastewater treated by micro-electrolysis is discharged into the flocculation sedimentation tank, and the pH value of the wastewater in the tank is adjusted to 8~10. Exposure After 30 minutes of gas treatment, part of the organic matter in the wastewater will be removed along with the generated precipitate, and the supernatant will enter the MVR evaporator for subsequent treatment;

(4) MVR evaporation: filter the wastewater treated in step (3), and then evaporate it to separate the salt in the waste liquid; the operating cost of the MVR evaporator is low, and the energy consumption for evaporating one ton of water is about 1/6 to 1/5 of the traditional evaporator. The normal operation of the MVR evaporator can be made by replacing the traditional steam boiler with electricity, and the emission of SO ₂ , CO ₂ , dust and solid waste is reduced during the production process, and the harm to the environment is small. Put the water sample treated in step (3) into the evaporator for treatment, and the NaCl salt in the wastewater is separated to obtain white NaCl salt. Part of the mother liquor must be reused, and the evaporated liquid is subjected to subsequent treatment;

(5) A/O process: The A-stage process mainly plays the role of denitrification and phosphorus removal, while the O-stage process is mainly used to degrade organic matter in the water. This process section performs biochemical treatment on the wastewater treated in step (4). It can hydrolyze the macromolecular organic matter in the wastewater into small molecular organic matter. Due to the use of the A/O process, the COD of the wastewater can be reduced and the ammonia nitrogen content in the wastewater can be effectively reduced;

(6) Electrocatalytic oxidation: Put the biochemically treated wastewater into the electrocatalytic oxidation device for electrocatalytic oxidation reaction, generate oxidized substances on the surface of the electrode, and deeply treat impurities in the wastewater. The COD removal rate reaches 99.8%, and finally discharged For wastewater, the anode of the electrocatalytic oxidation device is a titanium substrate modified tin-antimony electrode, doped with one or more of cerium nitrate, bismuth nitrate, and PTFE, and the cathode is stainless steel with the same area as the anode; the current density is 2mA/cm ² ~20mA/cm ² , the hydraulic retention time is 30-60min.

In this example, the industrial wastewater of a printing and dyeing factory will be described in detail. The alkaline wastewater of a printing and dyeing factory has a salt content of about 8.8%, the wastewater is dark black, the COD is about 19810, and the chroma is about 3500 times.

Specifically include the following steps:

Adding 3‰ amount of flocculation decolorizer to the above wastewater, the color of the raw water changed from dark black to light yellow, resulting in a large amount of flocculent precipitation, the chroma decreased by about 35%~45%, and the COD removal rate was 4.3%.

The wastewater after flocculation treatment enters the micro-electrolysis reactor for reaction. After 120 minutes of reaction, the chromaticity of the effluent is controlled at about 300 times, the chromaticity removal rate is 86%, and the COD removal rate is 31%.

The pH of the water sample after micro-electrolysis treatment was adjusted by calcium oxide to carry out the flocculation and precipitation process. The chromaticity of the effluent was about 30 times, the chromaticity removal rate was 99.1%, and the COD removal rate was 43%.

The above water sample was concentrated by MVR evaporator, and the salt was separated for later use. The distillate was subjected to biochemical treatment. The color of the distillate was colorless and transparent, and the COD removal rate was 90.1%.

The distillate is treated by the A/O process. After the wastewater is treated, the COD removal rate reaches 98%. Finally, the electrocatalytic oxidation process is used for advanced treatment. The final COD removal rate reaches 99.8%, meeting the emission requirements.

As stated above, while the invention has been shown and described with reference to certain preferred embodiments, this should not be construed as limiting the invention itself. Various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (3)

1. the device processing basic stain waste water, it is characterized in that, including the coagulative precipitation tank being sequentially connected with by pipeline, micro-electrolysis reactor, flocculation sedimentation tank, MVR vaporizer, A/O biochemistry pool and electrocatalysis oxidation apparatus, the import of described coagulative precipitation tank is connected with basic stain waste water inlet, and the outlet of electrocatalysis oxidation apparatus is connected with waste water discharge opening；Two electrodes of described electrocatalysis oxidation apparatus are metal electrode, and electric current density is 2mA/cm²~20mA/cm²。

2. the device of process basic stain waste water according to claim 1, it is characterized in that, the anode of described electrocatalysis oxidation apparatus be at the bottom of titanio modification stannum antimony electrode, doping cerous nitrate, bismuth nitrate, PTFE one of which or more than one, negative electrode is and the rustless steel of anode homalographic。

3. the device of process basic stain waste water according to claim 1, it is characterised in that described micro-electrolysis reactor is composed in series by one or more levels micro-electrolysis device, and the bottom of every grade of described micro-electrolysis device is provided with aerator。