DMF (Dimethyl Formamide) wastewater treatment system

Abstract

The utility model provides a DMF (Dimethyl Formamide) wastewater treatment system, and relates to the field of DMF wastewater treatment, the DMF wastewater treatment system comprises a pretreatment pool, an enhanced AO (Anaerobic Oxidation) pool communicated with the rear end of the pretreatment pool, a post-treatment pool communicated with the rear end of the enhanced AO pool, and the pretreatment pool is divided into a lime neutralization tank and an adsorption decolorization tank. According to the DMF wastewater treatment system, the pH value of wastewater is adjusted through the lime neutralization tank, filtered water adsorbs pigment and part of DMF through activated carbon, then the filtered water enters the iron-carbon micro-electrolysis tank, refractory pollutants are degraded through the micro-electrolysis effect by using filler as a mixture of activated carbon and iron powder, and then the pollutants are further removed under the action of hydrogen peroxide and Fe < + >; by means of aeration treatment and setting adjustment of the pH value, wastewater enters the ABR anaerobic tank and the anoxic and aerobic alternate reaction tank for reaction, the wastewater after reaction reaches the discharge standard through secondary precipitation and then enters the clear water tank, and pollutants in water can be effectively reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of DMF wastewater treatment, and particularly relates to a DMF wastewater treatment system. Background Technique

[0002] DMF wastewater is a kind of high-concentration organic wastewater, containing a large amount of DMF and other organic substances, with characteristics such as high COD, high BOD, and high toxicity. Moreover, DMF has stable properties and poor biodegradability, which can stimulate and damage people's eyes and cause liver function disorders. In China, the DMF wastewater discharged only from the synthetic leather industry reaches about 100 million tons per year, causing serious pollution to the environment.

[0003] The treatment methods of DMF wastewater are divided into the following several types:

[0004] Physical treatment method:

[0005] 1. Extraction method, advantages: It can effectively recover DMF and reduce the concentration of DMF in wastewater; disadvantages: The selection of extractant is relatively crucial, and there may be secondary pollution; the treatment cost is relatively high;

[0006] 2. Adsorption method, advantages: Simple operation, and has a certain effect on low-concentration DMF wastewater; disadvantages: The adsorbent needs to be replaced or regenerated regularly, with a relatively high cost; the adsorption capacity is limited;

[0007] Chemical treatment method:

[0008] 1. Hydrolysis method, advantages: It can convert DMF into substances that are easier to treat; disadvantages: The reaction conditions are relatively harsh, and parameters such as temperature and pressure need to be controlled; new pollutants may be generated;

[0009] 2. Oxidation method, advantages: It can effectively degrade DMF and has a relatively high removal efficiency; disadvantages: The cost of the oxidant is relatively high; special reaction equipment may be required;

[0010] Biological treatment method:

[0011] 1. Activated sludge method, advantages: The treatment cost is relatively low and is suitable for large-scale treatment; disadvantages: DMF may be toxic to microorganisms, affecting the treatment effect; a relatively long residence time is required.

[0012] 2. Biofilm method, advantages: The residence time of microorganisms is long, and the shock load resistance ability is relatively strong; disadvantages: The start-up time is long; the renewal and maintenance of the biofilm are relatively complex;

[0013] The source and characteristics of DMF wastewater determine that its treatment is relatively difficult because it not only contains refractory substances, but also contains a large amount of organic nitrogen and ammonia nitrogen. It is very difficult for conventional biochemical processes to convert organic nitrogen into ammonia nitrogen and then be treated by nitrifying bacteria. Moreover, the wastewater originally contains a large amount of ammonia nitrogen, resulting in an excessive biochemical treatment load;

[0014] After comprehensive consideration, the traditional DMF wastewater treatment generally adopts processes such as iron-carbon micro-electrolysis + precipitation + biochemical treatment, or catalytic oxidation. However, these treatment methods cannot effectively remove pollutants in the water. Content of the Utility Model

[0015] In view of the deficiencies of the prior art, the present utility model provides a DMF wastewater treatment system, which can effectively reduce the pollutants in the water.

[0016] Technical Solution

[0017] To achieve the above object, the present utility model is realized through the following technical solutions: A DMF wastewater treatment system includes a pretreatment tank. The rear end of the pretreatment tank is connected to an enhanced AO tank, and the rear end of the enhanced AO tank is connected to a post-treatment tank. The pretreatment tank is divided into a lime neutralization tank and an adsorption and decolorization tank. The rear end of the adsorption and decolorization tank is connected to an iron-carbon micro-electrolysis tank and a Fenton oxidation tank. The lime neutralization tank and the adsorption and decolorization tank are connected through a neutralization filter press. The adsorption and decolorization tank and the iron-carbon micro-electrolysis tank are connected and penetrated through a decolorization filter press. The enhanced AO tank is divided into an ABR anaerobic tank, and the rear end of the ABR anaerobic tank is connected to an anoxic-aerobic alternating reaction tank. The post-treatment tank includes an effluent Fenton oxidation tank and a coagulation sedimentation tank, and the rear end of the coagulation sedimentation tank is connected to a clear water tank.

[0018] Further, the decolorization filter press is provided with a sludge discharge port, and the sludge discharge port is a three-way, and one of the outlets is connected to the adsorption and decolorization tank.

[0019] Further, the pretreatment tank further includes an aeration stripping tank, the rear end of the aeration stripping tank is connected to a neutralization sedimentation tank, and the neutralization sedimentation tank is connected to the post-treatment tank.

[0020] Further, the anoxic-aerobic alternating reaction tank includes an anoxic tank one, an aerobic tank one, a sedimentation tank one, an anoxic tank two, an aerobic tank two, and a sedimentation tank two that are connected in sequence.

[0021] Further, lime is put into the lime neutralization tank, activated carbon is put into the adsorption and decolorization tank, and PAM is put into the neutralization sedimentation tank and the coagulation sedimentation tank.

[0022] Further, sodium hydroxide is put into the aeration stripping tank and the coagulation sedimentation tank.

[0023] The beneficial effects of the present utility model are as follows:

[0024] 1. The DMF wastewater treatment system adjusts the pH value of the wastewater through a lime neutralization tank. The filtered water adsorbs pigments and part of the DMF through activated carbon, and then enters an iron-carbon micro-electrolysis tank. The filler in the tank is a mixture of activated carbon and iron powder, and refractory pollutants are degraded through micro-electrolysis. Then, under the action of hydrogen peroxide and Fe⁺, pollutants are further removed. Through aeration treatment and pH value adjustment, the wastewater enters an ABR anaerobic tank and an anoxic-aerobic alternating reaction tank for reaction. The wastewater after the reaction reaches the discharge standard through secondary sedimentation and enters a clear water tank, effectively reducing the pollutants in the water.

[0025] 2. In the DMF wastewater treatment system, through the three-way of the decolorization filter press set, the activated carbon that has not been completely adsorbed after decolorization still has a certain adsorption capacity and is put back to the front end of the adsorption decolorization tank to continue adsorption decolorization, reducing the operating cost. Brief Description of the Drawings

[0026] Figure 1 It is a schematic diagram of the working process of the present utility model.

[0027] Among them, 1. Pretreatment tank; 2. Enhanced AO tank; 3. Post-treatment tank; 11. Lime neutralization tank; 12. Adsorption decolorization tank; 13. Iron-carbon micro-electrolysis tank; 14. Fenton oxidation tank; 15. Neutralization filter press; 16. Aeration stripping tank; 17. Decolorization filter press; 18. Neutralization sedimentation tank; 21. ABR anaerobic tank; 22. Anoxic-aerobic alternating reaction tank; 31. Water Fenton oxidation tank; 32. Coagulation sedimentation tank; 33. Clear water tank; 221. First anoxic tank; 222. First aerobic tank; 223. First sedimentation tank; 224. Second anoxic tank; 225. Second aerobic tank; 226. Second sedimentation tank. Detailed Embodiments

[0028] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0029] Refer to Figure 1 , a DMF wastewater treatment system, including a pretreatment tank 1. The pretreatment tank 1 preliminarily treats the sewage. The backend of the pretreatment tank 1 is connected to an enhanced AO tank 2, where high-intensity aerobic and anaerobic treatments can be carried out. The backend of the enhanced AO tank 2 is connected to a post-treatment tank 3, which can perform residual treatment on the treated sewage.

[0030] The pretreatment tank 1 is divided into a lime neutralization tank 11 and an adsorption decolorization tank 12. The lime neutralization tank 11 is connected to the adsorption decolorization tank 12 through a neutralization filter press 15. The pH of the incoming DMF-containing wastewater is relatively low and needs to be neutralized. After lime neutralization, solid-liquid separation is carried out through the neutralization filter press 15, and the pressed sludge is transported out for treatment. The interior of the adsorption decolorization tank 12 performs decolorization.

[0031] The rear end of the adsorption decolorization tank 12 is connected to an iron-carbon microelectrolysis tank 13 and a Fenton oxidation tank 14. The adsorption decolorization tank 12 is connected and penetrated with the iron-carbon microelectrolysis tank 13 through a decolorization filter press 17. The decolorization filter press 17 is provided with a sludge discharge port, and the sludge discharge port is a three-way. One of the outlets is connected to the adsorption decolorization tank 12. A part Q1 of the pressed sludge is transported out for treatment, and another part Q2 is refluxed to the front end of the adsorption decolorization tank 12.

[0032] After adsorption decolorization, solid-liquid separation is carried out through the decolorization filter press 17. The filtrate enters the iron-carbon microelectrolysis tank 13. After the iron-carbon microelectrolysis effluent, it enters the Fenton oxidation tank. Hydrogen peroxide is added. The Fe2+ generated by the microelectrolysis serves as a catalyst to generate hydroxyl radicals with strong oxidation ability for Fenton oxidation to remove pollutants and improve the B / C ratio again.

[0033] The enhanced AO tank 2 is divided into an ABR anaerobic tank 21. Utilizing the good treatment ability of anaerobic bacteria in the tank for macromolecular and refractory organic matters, the macromolecular and refractory substances in the wastewater are degraded into small molecular organic matters that are easily biodegradable. A multi-stage enhanced AO system is used instead of the traditional AO system to reasonably distribute the carbon source, reduce the carbon source dosage of the system, and simultaneously balance the degradation of carbon and nitrogen, achieving full degradation and removal without wasting the carbon source.

[0034] The rear end of the ABR anaerobic tank 21 is connected to an anoxic-aerobic alternating reaction tank 22. The anoxic-aerobic alternating reaction tank 22 includes anoxic tank one 221, aerobic tank one 222, sedimentation tank one 223, anoxic tank two 224, aerobic tank two 225, and sedimentation tank two 226 connected in sequence. The effluent from the ABR anaerobic tank 21 is divided into Q3 and Q4. Q3 goes to the anoxic tank one 221. A stirring device is provided in the anoxic tank one 221 to carry out denitrification reactions using the original water carbon source and the nitrite nitrogen and nitrate nitrogen in the nitrification liquid reflux Q5 and the sludge reflux Q6 from the sedimentation tank one 223, and then enters the aerobic tank one 222. The aerobic tank one 222 enters the sedimentation tank one 223 for solid-liquid separation.

[0035] The effluent of sedimentation tank 1 (223) is mixed with the raw water Q4 diverted from the ABR anaerobic tank 21 and then enters the second anoxic tank 224. A stirring device is installed in the second anoxic tank 224 to carry out denitrification reactions using the carbon source in the raw water and the nitrite nitrogen and nitrate nitrogen in the effluent of the first aerobic tank 222, the nitrification liquid return flow Q7, and the sludge return flow Q8 of sedimentation tank 2 (226). After that, it enters the second aerobic tank 225. The effluent of the ABR anaerobic tank 21 is distributed to the first anoxic tank 221 and the second anoxic tank 224 according to different proportions of Q3 and Q4 to form a multi-stage enhanced AO system.

[0036] Both the first aerobic tank 222 and the second aerobic tank 225 adopt lift aerators. The aeration volume is controlled by controlling the valves on each branch pipe, achieving precise aeration compared with traditional microporous aerators, saving aeration energy consumption. Compared with traditional microporous aerators, lift aerators can be replaced during system operation, facilitating the later maintenance and repair of the system.

[0037] The effluent of the second aerobic tank 225 enters sedimentation tank 2 (226) to achieve mud-water separation, and the sludge of sedimentation tank 2 (226) is refluxed to the second anoxic tank 224.

[0038] The post-treatment tank 3 includes an effluent Fenton oxidation tank 31 and a coagulation sedimentation tank 32. A clear water tank 33 is connected to the rear end of the coagulation sedimentation tank 32. The effluent enters the effluent Fenton oxidation tank 31. By accurately adding hydrogen peroxide and ferrous sulfate, hydroxyl radicals with strong oxidation ability are generated for Fenton oxidation to further remove pollutants and make the effluent meet the standards.

[0039] The pretreatment tank 1 also includes an aeration stripping tank 16. The wastewater after Fenton oxidation is introduced into the aeration stripping tank 16, and alkaline hydrolysis is carried out by adding alkali to adjust the pH of the wastewater. At the same time, the excess hydrogen peroxide can be stripped out through aeration to avoid the sludge in the neutralization sedimentation tank 18 being mixed with hydrogen peroxide bubbles, affecting the sedimentation effect.

[0040] The rear end of the aeration stripping tank 16 is connected to the neutralization sedimentation tank 18. PAM is added to the neutralization sedimentation tank 18 for mud-water separation, and the neutralization sedimentation tank 18 is connected to the post-treatment tank 3. Sodium hydroxide is put in the aeration stripping tank 16 and the coagulation sedimentation tank 32. A regulating tank is set between the neutralization sedimentation tank 18 and the post-treatment tank 3, and the regulating tank can be used to adjust the pH value.

[0041] Lime is put inside the lime neutralization tank 11. The incoming water enters the alkali intermediate tank, and the pH is adjusted to 6 - 8 by adding lime milk. Activated carbon is put in the adsorption decolorization tank 12. The pressure filtrate enters the adsorption decolorization tank 12 and activated carbon is added to remove most of the color and adsorb a part of DMF to reduce the content of DMF in the water. PAM is put in the neutralization sedimentation tank 18 and the coagulation sedimentation tank 32. The effluent of the Fenton oxidation tank 14 enters the coagulation sedimentation tank 32, and NaOH is added to adjust the pH, and PAM is added for mud-water separation. The effluent enters the clear water tank 33 and is discharged up to standard.

[0042] During use, the wastewater adjusts the pH value through the lime neutralization tank 11. The filtered water adsorbs pigments and part of DMF through activated carbon, and then enters the iron-carbon micro-electrolysis tank 13. The filler in the tank is a mixture of activated carbon and iron powder. Through the micro-electrolysis effect, the refractory pollutants are degraded. Then, under the action of hydrogen peroxide and Fe2+, the pollutants are further removed. Through aeration treatment and setting the pH value, the wastewater enters the ABR anaerobic tank 21 and the anoxic-aerobic alternating reaction tank 22 for reaction. The wastewater after the reaction reaches the discharge standard through secondary sedimentation and enters the clear water tank 33.

[0043] It should be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations.

[0044] The above is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and the inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A DMF wastewater treatment system, comprising a pretreatment tank (1), characterized in that: The rear end of the pre-treatment tank (1) is connected to the enhanced AO tank (2), and the rear end of the enhanced AO tank (2) is connected to the post-treatment tank (3); The pretreatment tank (1) is divided into a lime neutralization tank (11) and an adsorption decolorization tank (12); the rear end of the adsorption decolorization tank (12) is connected to an iron-carbon micro-electrolysis tank (13) and a Fenton oxidation tank (14); the lime neutralization tank (11) and the adsorption decolorization tank (12) are connected via a neutralization filter press (15); and the adsorption decolorization tank (12) and the iron-carbon micro-electrolysis tank (13) are connected and connected via a decolorization filter press (17); The enhanced AO tank (2) is divided into an ABR anaerobic tank (21), and the rear end of the ABR anaerobic tank (21) is connected to an anoxic aerobic alternating reaction tank (22); The post-treatment tank (3) comprises an effluent Fenton oxidation tank (31) and a coagulation sedimentation tank (32), and the rear end of the coagulation sedimentation tank (32) is connected to a clear water tank (33).

2. A DMF wastewater treatment system according to claim 1, characterized in that: The decolorizing filter press (17) is provided with a mud discharge port, which is a three-way port, one of the outlets of which is connected to the adsorption decolorizing tank (12).

3. A DMF wastewater treatment system according to claim 1, characterized in that: The pretreatment tank (1) further comprises an aeration stripping tank (16), the rear end of the aeration stripping tank (16) is connected to a neutralization sedimentation tank (18), and the neutralization sedimentation tank (18) is connected to the post-treatment tank (3).

4. A DMF wastewater treatment system according to claim 1, characterized in that: The anoxic aerobic alternating reaction pool (22) comprises anoxic pool 1 (221), aerobic pool 1 (222), sedimentation pool 1 (223), anoxic pool 2 (224), aerobic pool 2 (225) and sedimentation pool 2 (226) which are connected in sequence.

5. A DMF wastewater treatment system according to claim 1, characterized in that: Lime is placed inside the lime neutralization tank (11), activated carbon is placed in the adsorption decolorization tank (12), and PAM is placed in the neutralization sedimentation tank (18) and the coagulation sedimentation tank (32).

6. A DMF wastewater treatment system according to claim 3, characterized in that: Sodium hydroxide is added to the aeration stripping tank (16) and the coagulation sedimentation tank (32).

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