Nylon 66 wastewater treatment device and treatment method

Abstract

The invention discloses a nylon 66 wastewater treatment device, and belongs to the field of sewage treatment methods, the nylon 66 wastewater treatment device is sequentially connected with a primary aerobic treatment unit, an ABR hydrolysis treatment unit, a contact oxidation treatment unit, a secondary facultative treatment unit, an aerobic nitrification treatment unit and an effluent discharge pool; when the device is used for wastewater treatment, the hydrolysis reaction is facultative hydrolysis, aeration or stirring is reduced, energy consumption is reduced, the reactor does not produce methane, and a methane collection and follow-up treatment system can not be installed; and a contact oxidation treatment process is introduced in the facultative hydrolysis treatment process, so that a small amount of non-nylon 66 derived pollutants can be removed while nylon 66 derived substances are removed. And under the action of subsequent secondary facultative nitrification and aerobic nitrification, nitrogen can be removed by running a reflux mode.

Description

Technical Field

[0001] The present invention belongs to the field of sewage treatment methods, specifically relates to nylon 66 wastewater treatment technology, and specifically refers to a treatment device and method for nylon 66 wastewater. Background Art

[0002] Polyhexamethylene adipamide, also known as polyamide 66 (PA66) or nylon 66, is prepared by the polycondensation reaction of adipic acid and hexamethylenediamine. Nylon 66 is a semi-transparent or opaque milky white crystalline polymer. When irradiated by ultraviolet light, it will emit purple-white or blue-white light. It has relatively high mechanical strength, good stress cracking resistance, and is the PA with the best wear resistance. It has excellent self-lubrication, second only to polytetrafluoroethylene and polyoxymethylene. It also has good heat resistance (the thermal decomposition temperature of nylon 66 is higher than 350 °C, and the embrittlement temperature is -30 °C), belongs to a self-extinguishing material, has good chemical stability, especially excellent oil resistance, but is easily soluble in polar solvents such as phenol and formic acid. Adding carbon black can improve the weather resistance; it has a large water absorption (the equilibrium water absorption rate in the atmosphere is 2.5%), so its dimensional stability is poor, but it has good molding processability and can be used for injection molding, extrusion, blow molding, spraying, casting molding, machining, welding, and bonding.

[0003] There are many types of nylon 66 wastewater with complex components. The wastewater contains benzene series substances such as phenol, hexamethylenediamine, adipic acid, cyclohexanol, oligomers, and sulfides, with high ammonia nitrogen and organic nitrogen contents. The wastewater has poor biodegradability, is difficult to treat, has certain toxicity, and is difficult to biodegrade, belonging to difficult-to-treat industrial wastewater. At present, the treatment technologies for nylon 66 wastewater mainly include physical treatment technologies such as adsorption method, membrane separation method, and extraction method, as well as chemical treatment technologies such as catalytic microelectrolysis, coagulation method, and advanced oxidation method.

[0004] However, the cost of physical and chemical treatment technologies is generally high, and there are a large number of residues in the treated wastewater, making it difficult to achieve up-to-standard discharge. Biological treatment technologies such as aerobic method, anaerobic method, anaerobic-aerobic combined method, and emerging microorganism or bacteria adsorption or degradation method. The biological degradation method has the advantages of economy, high efficiency, and no secondary pollution, and can achieve full harmless treatment, which is the most widely used wastewater treatment technology. Therefore, using efficient biological agents is of great significance for solving the problem of nylon 66 wastewater pollution. Summary of the Invention

[0005] The present invention discloses a treatment device and method for nylon 66 wastewater in view of the problems existing in the prior art. The present invention is mainly based on the biological degradation method, uses multi-stage biological treatment technology, and at the same time recycles the products of biological treatment in the wastewater treatment process, thus solving the problems existing in the prior art.

[0006] The present invention is realized as follows:

[0007] A nylon 66 wastewater treatment device, which is successively connected with a first-stage aerobic treatment unit, an ABR hydrolysis treatment unit, a contact oxidation treatment unit, a second-stage facultative treatment unit, an aerobic nitrification treatment unit, and an effluent discharge tank.

[0008] The first-stage aerobic treatment unit includes a first-stage aerobic treatment unit inlet and a first-stage aerobic treatment unit outlet;

[0009] The ABR hydrolysis treatment unit includes an ABR hydrolysis treatment unit inlet and an ABR hydrolysis treatment unit outlet;

[0010] The contact oxidation treatment unit includes a contact oxidation treatment unit inlet, a contact oxidation treatment unit reflux outlet, and a contact oxidation treatment unit outlet;

[0011] The second-stage facultative treatment unit includes a second-stage facultative treatment unit inlet and a second-stage facultative treatment unit outlet;

[0012] The aerobic nitrification treatment unit includes an aerobic nitrification treatment unit inlet, an aerobic nitrification treatment unit reflux outlet, and an aerobic nitrification treatment unit outlet;

[0013] The connection relationship of the device is as follows: the outlet of the first-stage aerobic treatment unit is connected to the inlet of the ABR hydrolysis treatment unit, the outlet of the ABR hydrolysis treatment unit is connected to the inlet of the contact oxidation treatment unit, the contact oxidation treatment unit reflux outlet is connected to the inlet of the ABR hydrolysis treatment unit, the outlet of the contact oxidation treatment unit is connected to the inlet of the second-stage facultative treatment unit, the outlet of the second-stage facultative treatment unit is connected to the inlet of the aerobic nitrification treatment unit, the aerobic nitrification treatment unit reflux outlet is connected to the inlet of the second-stage facultative treatment unit, and the outlet of the aerobic nitrification treatment unit is connected to the effluent discharge tank.

[0014] Furthermore, the ABR hydrolysis treatment unit uses a highly efficient composite microbial agent as the microbial source in the reactor, strengthening the biological treatment efficiency, enabling the reactor to overcome sensitive factors such as ordinary anaerobic inability to handle high nitrogen-containing organic matter and high organic matter toxicity, expanding the applicable range of anaerobic reactors; it can also utilize the acid-producing hydrolysis part of the composite bacteria alone to meet the treatment requirements, improve the biodegradability of the effluent, and the reactor does not produce methane, so a methane collection and subsequent treatment system can be not installed.

[0015] Furthermore, the ABR hydrolysis treatment unit is a multi-stage folded-flow hydrolysis reactor, with a gas pressure balance hole at the top and a gas pipeline, and the number of stages ≥ 1.

[0016] Furthermore, the ABR hydrolysis treatment unit inlet of the ABR hydrolysis treatment unit is arranged on the first stage, the ABR hydrolysis treatment unit outlet is arranged on the last stage, and the outlet of the first-stage aerobic treatment unit is connected to the first stage of the ABR hydrolysis treatment unit.

[0017] Furthermore, an aeration device is installed at the bottom of the contact oxidation treatment unit and a mud discharge port is also provided.

[0018] The present invention also discloses a method for treating nylon 66 wastewater, which is characterized in that the method is as follows:

[0019] Step 1: placing the nylon 66 wastewater in a primary aerobic treatment unit for aerobic biochemical treatment after water quality adjustment, and degrading organic matter in the wastewater by aerobic biological bacteria; the aerobic biological bacteria include Bacillus, Alcaligenes, Proteus, nitrifying bacteria, and Thiobacillus;

[0020] Step 2: The effluent in step 1 enters the ABR hydrolysis treatment unit, and the anaerobic bacteria perform a hydrolysis reaction to improve the biodegradability of the effluent; the anaerobic bacteria include Gluconobacter oxidans, Lactobacillus fermentans, Lactobacillus brevis, Micrococcus luteus, Micrococcus halo, Pseudomonas alcaligenes, Pseudomonas aureogenes, Pseudomonas chlorophyllii, Pseudomonas nitrate-reducing, Pseudomonas riboflavin, Pseudomonas putida and Pseudomonas agile;

[0021] Step 3: subjecting the effluent from step 2 to contact oxidation treatment, and further degrading the organic matter in the wastewater by aerobic bacteria; the aerobic bacteria include Bacillus, Alcaligenes, Proteus, Nitrifying Bacteria, and Thiobacillus;

[0022] Step 4: Return the sludge finally produced in step 3 to the ABR hydrolysis treatment unit;

[0023] Step 5: The effluent from step 3 enters the secondary anoxic treatment unit to continue anoxic acid hydrolysis to improve the biodegradability of the effluent;

[0024] Step 6: aerobic nitrification treatment is performed on the effluent in step 5, and organic matter in the wastewater is further degraded by aerobic biological bacteria; the aerobic biological bacteria include Bacillus, Alcaligenes, Proteus, nitrifying bacteria, and Thiobacillus;

[0025] Step 7: returning the nitrified sludge liquid finally produced in step 6 to the secondary aerobic treatment unit;

[0026] The effluent from step six is coagulated and precipitated to make the effluent meet the discharge standards.

[0027] Furthermore, in the aerobic treatment unit of step 1, the absolute content of nylon 66 derivatives in the adjusted wastewater is ≤3500 mg / L; the salinity is ≤3%; and the pH value is within the range of 5.0 to 9.0.

[0028] Furthermore, the total nitrogen content of the influent treated by the ABR hydrolysis treatment unit in Step 2 is ≤500 mg / L; preferably, the total nitrogen content of the influent is ≤300 mg / L.

[0029] Furthermore, the ABR hydrolysis treatment unit in Step 2 can be applied to various harsh environments such as low temperature, high nitrogen-containing organic matter, and high toxicity. It can achieve satisfactory removal efficiency under a relatively high volumetric loading and can treat various wastewater suitable for anaerobic reactors.

[0030] Furthermore, in Step 4, the wastewater after contact oxidation treatment is refluxed to the ABR hydrolysis treatment unit for denitrification treatment at a reflux ratio of 100% - 200%; in Step 7, the wastewater after aerobic nitrification treatment is refluxed to the secondary facultative oxygen treatment unit for denitrification treatment at a reflux ratio of 100% - 200%.

[0031] The beneficial effects of the present invention compared with the prior art are as follows:

[0032] 1) Combining the system of the present invention, through the ABR hydrolysis treatment method, using the highly efficient composite microbial inoculant as the source of microorganisms in the reactor, the biological treatment efficiency is enhanced, enabling the reactor to overcome the sensitive factors such as high nitrogen-containing organic matter and high organic matter toxicity that ordinary anaerobic reactors cannot handle, and expanding the applicable range of anaerobic reactors;

[0033] 2) Through the ABR hydrolysis treatment method of the present invention, the problems of low degradation efficiency and poor economic benefits in the traditional treatment methods for nylon 66 and its intermediates are overcome;

[0034] 3) When using the device of the present invention for wastewater treatment, the hydrolysis reaction is facultative hydrolysis, reducing aeration or stirring, lowering energy consumption, and the reactor does not produce methane, so a methane collection and subsequent treatment system can be not installed; during the ABR hydrolysis treatment process, the contact oxidation treatment process is introduced simultaneously. While removing nylon 66 and its intermediate substances, it can also remove a small amount of pollutants other than nylon 66 and its intermediates;

[0035] 4) The ABR hydrolysis treatment method of the present invention has been verified to have the characteristics of high load tolerance, strong impact resistance, strong tolerance to high nitrogen-containing organic matter, stable effluent quality, easy maintenance, and is suitable for industrial applications;

[0036] 5) Using the device of the present invention for wastewater treatment, the hydrolysis reaction is facultative hydrolysis, reducing aeration or agitation, reducing energy consumption, and the reactor does not produce methane, so a methane collection and subsequent treatment system can be not installed; during the facultative hydrolysis treatment process, the contact oxidation treatment process is introduced simultaneously. While removing nylon 66-derived substances, a small amount of non-nylon 66-derived pollutants can also be removed. Through the subsequent effects of secondary facultative and aerobic nitrification, the operation of the reflux mode can achieve nitrogen removal. The device and method of the present invention have the characteristics of strong load tolerance, impact resistance, and strong tolerance to high nitrogen-containing organic matter, and the effluent water quality is stable, easy to maintain, and suitable for industrial applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a process flow chart of a method for treating nylon 66 wastewater of the present invention;

[0038] Figure 2 is a schematic structural diagram of a device for treating nylon 66 wastewater of the present invention;

[0039] Among them, 1 - primary aerobic treatment unit, 2 - ABR hydrolysis treatment unit, 3 - contact oxidation treatment unit, 4 - secondary facultative treatment unit, 5 - aerobic nitrification treatment unit, 6 - effluent discharge tank, 7 - inlet of the primary aerobic treatment unit, 8 - outlet of the primary aerobic treatment unit, 9 - inlet of the ABR hydrolysis treatment unit, 10 - outlet of the ABR hydrolysis treatment unit, 11 - inlet of the contact oxidation treatment unit, 12 - reflux outlet of the contact oxidation treatment unit, 13 - outlet of the contact oxidation treatment unit, 14 - inlet of the secondary facultative treatment unit, 15 - outlet of the secondary facultative treatment unit, 16 - inlet of the aerobic nitrification treatment unit, 17 - reflux outlet of the aerobic nitrification treatment unit, 18 - outlet of the aerobic nitrification treatment unit. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0040] In order to make the objectives, technical solutions and effects of the present invention clearer and more definite, the following further describes the present invention in detail with reference to the accompanying drawings and by way of examples.

[0041] As Figure 2 shown, the system of the present invention includes a primary aerobic treatment unit 1, an ABR hydrolysis treatment unit 2, a contact oxidation treatment unit 3, a secondary facultative treatment unit 4, an aerobic nitrification treatment unit 5, and an effluent discharge tank 6;

[0042] The primary aerobic treatment unit 1 performs aerobic biochemical treatment on nylon 66 wastewater after water quality adjustment, and degrades the organic matter in the wastewater through aerobic bacteria; the aerobic bacteria include Bacillus, Alcaligenes, Proteus, Nitrobacter, and Thiobacillus; the absolute content of nylon 66 in the adjusted wastewater ≤ 3500 mg / L; the salinity ≤ 3%; the pH value is in the range of 5.0 - 9.0.

[0043] The ABR hydrolysis unit 2 is a multi-stage folded hydrolysis reactor, which has a pneumatic balance hole at the top and a gas pipeline, and the number of stages ≥ 1.

[0044] The main function of the contact oxidation treatment unit is to achieve the degradation of pollutants such as nylon 66 derivatives.

[0045] The first-stage aerobic treatment unit 1 includes the first-stage aerobic treatment unit inlet 7 and the first-stage aerobic treatment unit outlet 8; the ABR hydrolysis treatment unit 2 includes the ABR hydrolysis treatment unit inlet 9 and the ABR hydrolysis treatment unit outlet 10; the contact oxidation treatment unit 3 includes the contact oxidation treatment unit inlet 11, the contact oxidation treatment unit reflux outlet 12, and the contact oxidation treatment unit outlet 13; the contact oxidation treatment unit 3 is provided with sludge discharge facilities.

[0046] The second-stage anoxic treatment unit further hydrolyzes the refractory substances to improve the subsequent biodegradability. The main function of the aerobic nitrification treatment unit is to continue to achieve the degradation of pollutants such as nylon 66 derivatives, and convert all ammonia nitrogen into nitrate radicals, and carry out denitrification and nitrogen removal by refluxing to the second-stage anoxic treatment unit.

[0047] The second-stage anoxic treatment unit 4 includes the second-stage anoxic treatment unit inlet 14 and the second-stage anoxic treatment unit outlet 15; the aerobic nitrification treatment unit 5 includes the aerobic nitrification treatment unit inlet 16 and the aerobic nitrification treatment unit reflux outlet 17; the aerobic nitrification treatment unit 5 is provided with sludge discharge facilities.

[0048] The aerobic nitrification treatment unit outlet 18 is connected to the effluent discharge tank 6.

[0049] The usage method of the device of the present invention is as follows:

[0050] As Figure 1 shown, first, the wastewater to be treated is introduced into the first-stage aerobic treatment unit for aerobic biochemical treatment. Specifically, the organic matter in the wastewater is degraded by aerobic bacteria; this is used as the preamble for the hydrolysis reaction.

[0051] Then, the wastewater treated by the first-stage aerobic treatment is sent into the ABR hydrolysis treatment unit, and anaerobic hydrolysis treatment is carried out under the action of the acid-producing hydrolysis part of the composite bacteria to improve the biodegradability of the effluent.

[0052] The wastewater after ABR hydrolysis treatment then enters the contact oxidation treatment unit. Under the environment of sufficient oxygen in the contact oxidation treatment unit, the aerobic bacteria further degrade the organic matter in the wastewater. Part of the sludge and nitrification liquid after contact oxidation treatment are refluxed to the ABR hydrolysis unit at a reflux ratio of 100% - 200% for denitrification and nitrogen removal.

[0053] The wastewater after contact oxidation treatment and then secondary anoxic treatment enters the aerobic nitrification treatment unit. In an environment with sufficient oxygen in the aerobic nitrification treatment unit, aerobic bacteria further degrade the organic matter in the wastewater, and the remaining ammonia nitrogen is converted into nitrate. Part of the sludge and nitrification liquid after aerobic nitrification treatment are refluxed to the secondary anoxic unit for denitrification and nitrogen removal at a reflux ratio of 100% - 200%. The experimental data are shown in Tables 1 - 3 below.

[0054] Experimental data table

[0055] Table 1 Changes in indexes of nylon 66 wastewater before and after biochemical experiment

[0056]

[0057]

[0058] Table 2 Changes in indexes of aerobic effluent before and after nitrification experiment

[0059]

[0060] Table 3 Changes in indexes of nitrification effluent before and after denitrification experiment

[0061]

[0062] The above is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, several improvements can be made without departing from the principle of the present invention, and these improvements should also be regarded as the protection scope of the present invention.

Claims

1. A treatment device for nylon 66 wastewater, characterized in that, The described device sequentially includes: a primary aerobic treatment unit (1), an ABR hydrolysis treatment unit (2), a contact oxidation treatment unit (3), a secondary facultative anaerobic treatment unit (4), an aerobic nitrification treatment unit (5), and an effluent discharge tank (6); The primary aerobic treatment unit (1) includes a primary aerobic treatment unit inlet (7) and a primary aerobic treatment unit outlet (8); the ABR hydrolysis treatment unit (2) includes an ABR hydrolysis treatment unit inlet (9) and an ABR hydrolysis treatment unit outlet (10); the contact oxidation treatment unit (3) includes a contact oxidation treatment unit inlet (11), a contact oxidation treatment unit reflux outlet (12), and a contact oxidation treatment unit outlet (13); the secondary facultative anaerobic treatment unit (4) includes a secondary facultative anaerobic treatment unit inlet (14) and a secondary facultative anaerobic treatment unit outlet (15); the aerobic nitrification treatment unit (5) includes an aerobic nitrification treatment unit inlet (16), an aerobic nitrification treatment unit reflux outlet (17), and an aerobic nitrification treatment unit outlet (18); The connection relationship of the described device is: the primary aerobic treatment unit outlet (8) is connected to the ABR hydrolysis treatment unit inlet (9), the ABR hydrolysis treatment unit outlet (10) is connected to the contact oxidation treatment unit inlet (11), the contact oxidation treatment unit reflux outlet (12) is connected to the ABR hydrolysis treatment unit inlet (9), the contact oxidation treatment unit outlet (13) is connected to the secondary facultative anaerobic treatment unit inlet (14), the secondary facultative anaerobic treatment unit outlet (15) is connected to the aerobic nitrification treatment unit inlet (16), the aerobic nitrification treatment unit reflux outlet (17) is connected to the secondary facultative anaerobic treatment unit inlet (14), and the aerobic nitrification treatment unit outlet (18) is connected to the effluent discharge tank (6).

2. The treatment device for nylon 66 wastewater according to claim 1, characterized in that, The described The ABR hydrolysis treatment unit (2) uses a composite microbial inoculum as the source of microorganisms in the reactor.

3. The treatment device for nylon 66 wastewater according to claim 1 or 2, characterized in that, The ABR hydrolysis treatment unit (2) is a multi-stage folded hydrolysis reactor with a pressure balance hole at the top and a gas conduction pipeline, and its number of stages ≥ 1.

4. The treatment device for nylon 66 wastewater according to claim 3, characterized in that, The described The ABR hydrolysis treatment unit inlet (9) of the ABR hydrolysis treatment unit (2) is arranged on the first stage, the ABR hydrolysis treatment unit outlet (10) is arranged on the last stage, and the primary aerobic treatment unit outlet (8) is connected to the first stage of the ABR hydrolysis treatment unit (2).

5. The treatment device for nylon 66 wastewater according to claim 1, characterized in that, An aeration device is installed at the bottom of the contact oxidation treatment unit (3) and a sludge discharge port is provided.

6. The treatment method of a nylon 66 wastewater treatment device according to any one of claims 1 to 5, characterized in that, The method is as follows: Step 1: After adjusting the water quality of the nylon 66 wastewater, place it in the primary aerobic treatment unit (1) for aerobic biochemical treatment, and degrade the organic matter in the wastewater through aerobic bacteria; the aerobic bacteria include Bacillus, Alcaligenes, Proteus, Nitrobacter, and Thiobacillus; Step 2: Feed the effluent from Step 1 into the ABR hydrolysis treatment unit (2), and conduct hydrolysis reaction through anaerobic bacteria to improve the biodegradability of the effluent. The anaerobic bacteria include Gluconobacter oxydans, Lactobacillus fermentum, Lactobacillus brevis, Micrococcus luteus, Micrococcus halobius, Pseudomonas alcaligenes, Pseudomonas aurantiaca, Pseudomonas viridiflava, Pseudomonas nitrate reductans, Pseudomonas riboflavina, Pseudomonas putida, and Pseudomonas agilis. Step 3: Conduct contact oxidation treatment (3) on the effluent from Step 2, and further degrade the organic matter in the wastewater through aerobic bacteria. The aerobic bacteria include Bacillus, Alcaligenes, Proteus, Nitrifying bacteria, and Thiobacillus. Step 4: Return the sludge nitrification liquid finally produced in Step 3 to the ABR hydrolysis treatment unit (2). Step 5: Feed the effluent from Step 3 into the secondary anoxic treatment unit (4) to continue anoxic acid production and hydrolysis to improve the biodegradability of the effluent. Step 6: Conduct aerobic nitrification treatment (5) on the effluent from Step 5, and further degrade the organic matter in the wastewater through aerobic bacteria. The aerobic bacteria include Bacillus, Alcaligenes, Proteus, Nitrifying bacteria, and Thiobacillus. Step 7: Return the sludge nitrification liquid finally produced in Step 6 to the secondary anoxic treatment unit (4). Coagulate and precipitate the effluent from Step 6 to make the effluent meet the discharge standards.

7. The treatment device for nylon 66 wastewater according to claim 6, characterized in that, In the aerobic treatment unit of Step 1: The absolute content of nylon 66 derived from the adjusted wastewater ≤ 3500 mg / L; the salinity ≤ 3%; the pH value ranges from 5.0 to 9.

0.

8. The treatment device for nylon 66 wastewater according to claim 6, characterized in that, The total nitrogen content of the influent treated by the ABR hydrolysis treatment unit (2) in Step 2 ≤ 500 mg / L.

9. The treatment device for nylon 66 wastewater according to claim 6, wherein, The ABR hydrolysis treatment unit (2) in Step 2 is applicable to various harsh environments with low temperature, high nitrogen-containing organic matter, and high toxicity, and can achieve satisfactory removal efficiency under relatively high volumetric load, and can treat various wastewaters suitable for anaerobic reactors.

10. The treatment device for nylon 66 wastewater according to claim 6, wherein, In Step 4, the wastewater after contact oxidation treatment is refluxed to the ABR hydrolysis treatment unit (2) for denitrification treatment at a reflux ratio of 100% - 200%; in Step 7, the wastewater after aerobic nitrification treatment is refluxed to the secondary anoxic treatment unit (4) for denitrification treatment at a reflux ratio of 100% - 200%.

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