CN116589126A - Caprolactam wastewater treatment method - Google Patents
Caprolactam wastewater treatment method Download PDFInfo
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- CN116589126A CN116589126A CN202310570477.2A CN202310570477A CN116589126A CN 116589126 A CN116589126 A CN 116589126A CN 202310570477 A CN202310570477 A CN 202310570477A CN 116589126 A CN116589126 A CN 116589126A
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- JBKVHLHDHHXQEQ-UHFFFAOYSA-N epsilon-caprolactam Chemical compound O=C1CCCCCN1 JBKVHLHDHHXQEQ-UHFFFAOYSA-N 0.000 title claims abstract description 74
- 238000004065 wastewater treatment Methods 0.000 title claims abstract description 18
- 239000002351 wastewater Substances 0.000 claims abstract description 117
- 238000011282 treatment Methods 0.000 claims abstract description 74
- 239000010802 sludge Substances 0.000 claims abstract description 50
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 43
- 238000000034 method Methods 0.000 claims abstract description 41
- 238000004062 sedimentation Methods 0.000 claims abstract description 39
- 230000001105 regulatory effect Effects 0.000 claims abstract description 29
- 230000008569 process Effects 0.000 claims abstract description 26
- 230000020477 pH reduction Effects 0.000 claims abstract description 19
- CBENFWSGALASAD-UHFFFAOYSA-N Ozone Chemical compound [O-][O+]=O CBENFWSGALASAD-UHFFFAOYSA-N 0.000 claims abstract description 15
- 230000003301 hydrolyzing effect Effects 0.000 claims abstract description 12
- 238000005342 ion exchange Methods 0.000 claims abstract description 11
- 230000003647 oxidation Effects 0.000 claims abstract description 8
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 8
- 230000003197 catalytic effect Effects 0.000 claims abstract description 5
- 238000011946 reduction process Methods 0.000 claims abstract description 5
- 230000001112 coagulating effect Effects 0.000 claims description 20
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 16
- 229910052799 carbon Inorganic materials 0.000 claims description 16
- 238000006243 chemical reaction Methods 0.000 claims description 15
- 230000007062 hydrolysis Effects 0.000 claims description 14
- 238000006460 hydrolysis reaction Methods 0.000 claims description 14
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 12
- 239000002253 acid Substances 0.000 claims description 11
- 238000006146 oximation reaction Methods 0.000 claims description 11
- 239000003513 alkali Substances 0.000 claims description 6
- 239000000701 coagulant Substances 0.000 claims description 6
- 229920002521 macromolecule Polymers 0.000 claims description 6
- 125000003367 polycyclic group Chemical group 0.000 claims description 6
- 239000000203 mixture Substances 0.000 claims description 4
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 3
- 230000018044 dehydration Effects 0.000 claims description 3
- 238000006297 dehydration reaction Methods 0.000 claims description 3
- 230000029087 digestion Effects 0.000 claims description 3
- 239000000706 filtrate Substances 0.000 claims description 3
- 229910052760 oxygen Inorganic materials 0.000 claims description 3
- 239000001301 oxygen Substances 0.000 claims description 3
- 238000010992 reflux Methods 0.000 claims description 3
- QAOWNCQODCNURD-UHFFFAOYSA-N sulfuric acid Substances OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 3
- 239000006228 supernatant Substances 0.000 claims description 3
- 238000005516 engineering process Methods 0.000 claims description 2
- 238000001914 filtration Methods 0.000 claims 1
- 239000003344 environmental pollutant Substances 0.000 abstract description 4
- 231100000719 pollutant Toxicity 0.000 abstract description 4
- 238000001556 precipitation Methods 0.000 abstract description 3
- 230000009897 systematic effect Effects 0.000 abstract description 2
- 230000015271 coagulation Effects 0.000 abstract 2
- 238000005345 coagulation Methods 0.000 abstract 2
- 238000005189 flocculation Methods 0.000 abstract 1
- 230000016615 flocculation Effects 0.000 abstract 1
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 25
- 229910052757 nitrogen Inorganic materials 0.000 description 12
- 241000894006 Bacteria Species 0.000 description 10
- XKMRRTOUMJRJIA-UHFFFAOYSA-N ammonia nh3 Chemical compound N.N XKMRRTOUMJRJIA-UHFFFAOYSA-N 0.000 description 8
- 230000000694 effects Effects 0.000 description 8
- IOVCWXUNBOPUCH-UHFFFAOYSA-M Nitrite anion Chemical compound [O-]N=O IOVCWXUNBOPUCH-UHFFFAOYSA-M 0.000 description 7
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 6
- 229920002401 polyacrylamide Polymers 0.000 description 6
- 239000002245 particle Substances 0.000 description 5
- JHIVVAPYMSGYDF-UHFFFAOYSA-N cyclohexanone Chemical compound O=C1CCCCC1 JHIVVAPYMSGYDF-UHFFFAOYSA-N 0.000 description 4
- 125000000623 heterocyclic group Chemical group 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 244000005700 microbiome Species 0.000 description 4
- 230000009467 reduction Effects 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 229910002651 NO3 Inorganic materials 0.000 description 3
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 3
- MMDJDBSEMBIJBB-UHFFFAOYSA-N [O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[NH6+3] Chemical compound [O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O.[NH6+3] MMDJDBSEMBIJBB-UHFFFAOYSA-N 0.000 description 3
- 125000000751 azo group Chemical group [*]N=N[*] 0.000 description 3
- 230000006872 improvement Effects 0.000 description 3
- 241001478240 Coccus Species 0.000 description 2
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 2
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 description 2
- 229910052921 ammonium sulfate Inorganic materials 0.000 description 2
- 235000011130 ammonium sulphate Nutrition 0.000 description 2
- 230000015556 catabolic process Effects 0.000 description 2
- 238000006731 degradation reaction Methods 0.000 description 2
- 238000007599 discharging Methods 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 239000000693 micelle Substances 0.000 description 2
- 150000002978 peroxides Chemical class 0.000 description 2
- 229910052698 phosphorus Inorganic materials 0.000 description 2
- 239000011574 phosphorus Substances 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 241000193830 Bacillus <bacterium> Species 0.000 description 1
- 241000589989 Helicobacter Species 0.000 description 1
- 102000004157 Hydrolases Human genes 0.000 description 1
- 108090000604 Hydrolases Proteins 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- CKUAXEQHGKSLHN-UHFFFAOYSA-N [C].[N] Chemical compound [C].[N] CKUAXEQHGKSLHN-UHFFFAOYSA-N 0.000 description 1
- 230000002053 acidogenic effect Effects 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000002306 biochemical method Methods 0.000 description 1
- 230000003851 biochemical process Effects 0.000 description 1
- 238000005842 biochemical reaction Methods 0.000 description 1
- 125000002091 cationic group Chemical group 0.000 description 1
- 238000001311 chemical methods and process Methods 0.000 description 1
- 239000000084 colloidal system Substances 0.000 description 1
- 230000000593 degrading effect Effects 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000000813 microbial effect Effects 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000001546 nitrifying effect Effects 0.000 description 1
- 239000005416 organic matter Substances 0.000 description 1
- 125000001477 organic nitrogen group Chemical group 0.000 description 1
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 238000005185 salting out Methods 0.000 description 1
- 239000013049 sediment Substances 0.000 description 1
- 239000010865 sewage Substances 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 238000009279 wet oxidation reaction Methods 0.000 description 1
Classifications
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F9/00—Multistage treatment of water, waste water or sewage
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F11/00—Treatment of sludge; Devices therefor
- C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
- C02F11/121—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering
- C02F11/122—Treatment of sludge; Devices therefor by de-watering, drying or thickening by mechanical de-watering using filter presses
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
- C02F1/54—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using organic material
- C02F1/56—Macromolecular compounds
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/72—Treatment of water, waste water, or sewage by oxidation
- C02F1/78—Treatment of water, waste water, or sewage by oxidation with ozone
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F2001/007—Processes including a sedimentation step
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/30—Organic compounds
- C02F2101/34—Organic compounds containing oxygen
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/30—Organic compounds
- C02F2101/38—Organic compounds containing nitrogen
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
- C02F2103/34—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32
- C02F2103/36—Nature of the water, waste water, sewage or sludge to be treated from industrial activities not provided for in groups C02F2103/12 - C02F2103/32 from the manufacture of organic compounds
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2209/00—Controlling or monitoring parameters in water treatment
- C02F2209/08—Chemical Oxygen Demand [COD]; Biological Oxygen Demand [BOD]
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2209/00—Controlling or monitoring parameters in water treatment
- C02F2209/14—NH3-N
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2209/00—Controlling or monitoring parameters in water treatment
- C02F2209/16—Total nitrogen (tkN-N)
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F3/00—Biological treatment of water, waste water, or sewage
- C02F3/28—Anaerobic digestion processes
- C02F3/2846—Anaerobic digestion processes using upflow anaerobic sludge blanket [UASB] reactors
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F3/00—Biological treatment of water, waste water, or sewage
- C02F3/30—Aerobic and anaerobic processes
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W10/00—Technologies for wastewater treatment
- Y02W10/10—Biological treatment of water, waste water, or sewage
Abstract
The invention discloses a caprolactam wastewater treatment method, and relates to the technical field of wastewater treatment. The caprolactam wastewater treatment method disclosed by the invention comprises the following steps: respectively carrying out pretreatment on the collected ion exchange wastewater and ammoximation wastewater by adopting an acidolysis reduction process after passing through an adjusting tank; after the water quality and the water quantity of the pretreated wastewater are regulated together with the wastewater of other process sections, the wastewater is treated by a primary sedimentation tank, and sequentially enters a hydrolytic acidification tank and an upflow anaerobic sludge tank for double anaerobic treatment; then carrying out ozone catalytic oxidation after primary A/O biochemical system treatment, precipitation and coagulation treatment; the wastewater from the ozone pool is subjected to secondary A/O biochemical treatment and then is subjected to precipitation and coagulation flocculation treatment. The caprolactam wastewater treatment method of the invention has stable, reliable, efficient and systematic operation, solves the problem of poor biodegradability of caprolactam wastewater, reduces the pollutant concentration, biotoxicity and the like of the wastewater, ensures that the effluent reaches the standard, and greatly reduces the investment and the running cost.
Description
Technical Field
The invention relates to the technical field of wastewater treatment, in particular to a caprolactam comprehensive wastewater treatment method.
Background
The caprolactam production belongs to a chemical reaction process, and a plurality of completely different working sections such as oximation, hydrogen peroxide, ammonium sulfate, cyclohexanone and the like are used for carrying out the reaction between completely different materials, and the reaction is a complex chemical process, so that caprolactam wastewater contains a large amount of azo, heterocycle, benzene ring, peroxide, ammonia nitrogen, nitrate, phosphate and other various organic matters and inorganic matters. The average COD value of pure caprolactam wastewater is generally 3000-6000 mg/L, and if the data is far higher than the average COD value in an accident state or in a concentrated discharge state of ion exchange wastewater; the ammonia nitrogen is generally between 300 and 500mg/L on average, the total nitrogen is generally between 500 and 1000mg/L, and the total nitrogen is 100 to 200mg/L of organic nitrogen; the total phosphorus generally exists in the hydrogen peroxide wastewater, and the data of each set of device is quite different and is generally between 200 and 500 mg/L. Therefore, the COD, total nitrogen and total phosphorus of the caprolactam wastewater are required to be removed greatly, so that the effluent can be discharged up to the standard. Because of the characteristics of caprolactam production, caprolactam waste water, particularly oximation waste water and ion exchange waste water, contains a large amount of azo, heterocyclic and polycyclic organic matters, has poor biodegradability, and generally has B/C of less than 0.1, so that the integral caprolactam waste water belongs to the category of difficult biochemical waste water.
Because oximation wastewater contains a large amount of azo and heterocyclic refractory organic matters, the biodegradability of the oximation wastewater is extremely poor, pretreatment is needed, and part of COD is removed on the basis of improving the B/C ratio so as to ensure the normal operation of a subsequent biochemical system. At present, the existing domestic caprolactam wastewater is generally treated by a biochemical method, but with the improvement of the wastewater discharge water quality requirement, the pure biochemical mode can not meet the discharge requirement. The pretreatment means such as Fenton oxidation and ozone oxidation are combined with the biochemical treatment to obtain a better treatment effect, however, the investment and the operation cost of the processes are relatively high, the treated water quantity is relatively small, the concentrated water part of the caprolactam production wastewater is usually treated, no clear and reasonable treatment mode is provided for the rest of the wastewater in a factory, and in the actual operation of the Fenton oxidation process, the control of peroxide is easy to cause large fluctuation due to the reasons of water inlet and operation, so that the subsequent biochemical treatment is impacted. Film treatment is also a recent research hotspot, but the problem of film pollution caused by a simple film treatment method cannot be well solved. Treatment modes such as a salting-out method, a wet oxidation method, a high-temperature incineration method and the like are also developed at home and abroad, and can thoroughly remove pollutants, but the problems of high treatment energy consumption and high cost still exist.
Disclosure of Invention
The invention aims to provide a caprolactam wastewater treatment method which is stable, reliable, efficient and systematic in operation, effectively treats comprehensive wastewater discharged in a caprolactam production process, solves the problem of poor biodegradability of caprolactam wastewater, reduces pollutant concentration, biotoxicity and the like of the wastewater, ensures that effluent reaches the standard, and greatly reduces investment and operation cost.
In order to achieve the aim of the invention, the invention provides a caprolactam wastewater treatment method, which specifically comprises the following steps:
s1, respectively passing collected ion exchange wastewater and ammoximation wastewater through an adjusting tank, and then pretreating by adopting an acidolysis reduction process to obtain pretreated wastewater;
s2, conveying the pretreated wastewater and the wastewater of other process sections to a comprehensive regulating tank to regulate the water quality and water quantity, treating the mixed wastewater by a primary sedimentation tank, and sequentially entering a hydrolytic acidification tank and an upflow anaerobic sludge tank for double anaerobic treatment;
s3, the wastewater subjected to double anaerobic treatment enters a first-stage A/O biochemical system for treatment;
s4, sequentially treating the wastewater subjected to biochemical treatment by a secondary sedimentation tank and a coagulating sedimentation tank 1, and then entering an ozone tank for ozone catalytic oxidation;
s5, the wastewater from the ozone tank is subjected to secondary A/O biochemical treatment, enters a triple sedimentation tank, is treated by a coagulating sedimentation tank 2, and is discharged and sent into a clean water tank, so that the reclaimed water reaching the discharge standard is obtained.
Further, in the step S1, the acidolysis reduction process includes the steps of: the wastewater from the regulating tank is fed into an acid regulating tank, the pH value is regulated to 2-4 after concentrated sulfuric acid is added, and then the wastewater is fed into an acid reaction tank, and polycyclic organic matters and azo organic matters are added for acidolysis reaction, so that macromolecular substances in the wastewater are degraded; then the mixture is sent into an alkali regulating tank, the pH value is regulated to 6 to 8 by using NaOH solution, and then the mixture is sent into an oximation intermediate water tank.
Further, in the step S1, the B/C value of the pretreated wastewater is 0.30-0.35, and the COD of the whole biochemical effluent is 100-130 mg/L.
Further, in the hydrolysis acidification tank in the step S2, the hydrolysis acidification treatment time is 3-4 h, the temperature of the hydrolysis acidification treatment is normal temperature, and the concentration of dissolved oxygen in the hydrolysis acidification treatment is less than 2mg/L.
Furthermore, the primary A/O biochemical system adopts a two-section A/O process combination, namely the wastewater after double anaerobic treatment is sequentially treated by a primary section A pool, a primary section O pool, a primary secondary section A pool and a primary secondary section O pool, the primary section O pool and the primary section A pool adopt a digestion liquid reflux mode, alkali liquor is added into the effluent of the primary section O pool to adjust the pH value to 7-8, and an external carbon source is required to be added into the primary secondary section A pool.
Further, part of sludge from the secondary sedimentation tank flows back to the primary first-stage A tank to serve as a carbon source, and the other part of sludge is directly discharged.
Further, the secondary A/O biochemical treatment process sequentially passes through a secondary A pool and a secondary O pool; the secondary A pool adopts an external carbon source and hydrolytic BOD in wastewater as carbon sources, and the secondary O pool is added with a biological carrier.
Further, the sludge discharged from the coagulating sedimentation tank 2 and part of the sludge in the triple sedimentation tank are conveyed to a sludge concentration tank, PAM is added into the concentrated sludge, the sludge is conveyed to a filter press for filter pressing and dehydration, the obtained sludge cake is conveyed to a sludge drier, and finally the dried sludge is conveyed to the outside; the supernatant recovered from the sludge concentration tank and the filtrate recovered from the filter press are refluxed to the integrated regulating tank together.
Furthermore, coagulant and flocculant are added into the coagulating sedimentation tank 1 and the coagulating sedimentation tank 2.
Further, the coagulant is PAC, and the flocculant is PAM.
The invention has the following beneficial effects:
1. aiming at the characteristics that the ion-exchange wastewater and the ammoximation wastewater contain a large amount of azo, heterocyclic and polycyclic organic matters and have poor biodegradability, the invention pretreats the ion-exchange wastewater and the ammoximation wastewater by acidolysis reduction to remove the refractory polycyclic organic matters and azo organic matters, so that the B/C of the wastewater is greatly improved to more than 0.3, but the COD removal rate is reduced to 35 percent from 50 percent of the raw materials, but the investment and the running cost can be saved to the greatest extent, the final treatment effect of the caprolactam wastewater can be ensured, and the yielding water reaches the standard.
2. The invention adopts the double anaerobic process of hydrolytic acidification and up-flow internal circulation anaerobic sludge pond, enhances the impact resistance of a treatment system, reduces the biochemical risk, reduces the load of a subsequent A/O biochemical treatment system, avoids the short-time impact of high-concentration COD and reduces the risk; according to the characteristics of high ammonia nitrogen and low carbon nitrogen ratio of the inflow water, the invention designs a primary biochemical harbor type of a first-stage A/O+a second-stage A/O, and improves the total nitrogen removal effect. Therefore, the stable operation of COD and total nitrogen removal efficiency and impact resistance is integrated, and the biochemical treatment of wastewater is ensured by using the combination of a double anaerobic process of a hydrolytic acidification and up-flow internal circulation anaerobic reaction tank and a two-stage A/O process.
3. The invention sets the ozone pool before the second-stage A/O technology, which can further open the ring and break the chain of the residual organic macromolecule which is difficult to be biochemically degraded after the first-stage A/O biochemical treatment, improves the biodegradability of the second-stage A/O water inlet, improves the COD degradation efficiency of the second-stage A/O treatment unit, reduces the COD of the water outlet and lightens the operation pressure of the subsequent treatment unit.
4. The invention adopts the coagulating sedimentation tank as the terminal treatment, can take out suspended particles with small particle size in the wastewater, and can also take out chromaticity, oil content, microorganisms, organic matters and the like, thereby ensuring that the effluent finally reaches the standard.
5. The invention can realize the standard reaching of the caprolactam comprehensive wastewater, improves the treatment efficiency and effect of the caprolactam wastewater, and reduces the investment and operation cost of enterprises.
Drawings
FIG. 1 is a flow chart of the caprolactam wastewater treatment process of the present invention.
Detailed Description
The following describes specific embodiments of the present invention in detail with reference to the drawings. All of the features disclosed in this specification, or all of the steps in a method or process disclosed, may be combined in any combination, except for mutually exclusive features and/or steps.
The invention will be further described with reference to the accompanying drawings and examples
Example 1
As shown in FIG. 1, the caprolactam wastewater treatment method provided by the invention specifically comprises the following steps:
s1, respectively carrying out water quality and water quantity balance on collected ion-exchange wastewater and ammoximation wastewater through an ion-exchange wastewater regulating tank and an oximation wastewater regulating tank; then, the oximation wastewater from two different regulating tanks is conveyed to an acid regulating reaction tank (namely an acid regulating tank), and concentrated sulfuric acid is added to regulate the pH value of the acid regulating tank to 2-4; then the waste water is sent into an acid reaction tank, polycyclic organic matters and azo organic matters are added into the acid reaction tank to carry out acidolysis reaction, so that macromolecular substances in the oximation waste water are degraded, the COD removal rate is reduced, the COD of the whole biochemical effluent is 100-300 mg/L, the biodegradability of the waste water is greatly improved, and the B/C is obviously more than 0.3; and (3) feeding the wastewater into an alkali regulating tank, regulating the pH value to 6-8 by using NaOH solution, and feeding the wastewater into an oximation intermediate water tank to obtain pretreated wastewater.
S2, conveying the pretreated wastewater and other process section wastewater (such as hydrogen peroxide wastewater, ammonium sulfate wastewater, cyclohexanone wastewater and the like) to a comprehensive regulating tank for regulating water quality and water quantity balance; then adding cationic polyacrylamide into the mixed wastewater to perform ordinary precipitation treatment in a primary sedimentation tank, enabling the effluent to enter a hydrolysis acidification tank, and performing hydrolysis acidification treatment for 3-4 hours under the condition of normal temperature and when the dissolved oxygen concentration is less than 2mg/L, so as to improve the biodegradability of the wastewater and reduce the subsequent treatment cost; the effluent enters an upflow anaerobic sludge tank, so that the biodegradability of the wastewater is further improved, and organic matters in the wastewater are removed. The embodiment adopts a double anaerobic process of hydrolytic acidification and up-flow internal circulation anaerobic sludge tank, can further greatly improve the biodegradability of the wastewater, enables the B/C of the comprehensive wastewater to be more than 0.4, reduces the COD concentration, improves the total nitrogen removal rate, reduces the load of subsequent A/O biochemical treatment, avoids the short-time impact of high-concentration COD, reduces the risk, and enables the system to stably operate.
The hydrolysis treatment method is a method between the aerobic treatment method and the anaerobic treatment method, and other process combinations can reduce the treatment cost and improve the treatment efficiency. Hydrolysis refers to the biochemical reaction that takes place extracellular before the organic matter enters the microbial cells. The hydrolysis (acidification) treatment method is a process of the anaerobic treatment in the early stage, according to different growth conditions of methanogens and acidogenic hydrolases, the anaerobic treatment is controlled under the condition of containing a large number of hydrolytic bacteria and acidizing bacteria, and the hydrolytic bacteria and the acidizing bacteria are utilized to hydrolyze insoluble organic matters in water into soluble organic matters, so that the macromolecular substances which are difficult to biodegrade are converted into the micromolecular substances which are easy to biodegrade, thereby improving the biodegradability of the wastewater and providing a good water quality environment for the subsequent biochemical treatment. In the embodiment, the anaerobic digestion reaction is controlled only in the hydrolysis and acidification processes, no or only a small amount of biogas is generated, and no granular sludge is generated, so that the purposes of improving the biodegradability of sewage and reducing the subsequent treatment cost are achieved.
S3, after double anaerobic treatmentThe wastewater enters a first-stage A pool, a first-stage O pool, a first-stage second-stage A pool and a first-stage second-stage O pool in sequence for A/O process treatment. A is an anaerobic section for denitrification and dephosphorization, and under the anoxic condition, the denitrification of the iso-aerobic bacteria returns NO in the aerobic tank 3- Reduction to molecular nitrogen (N) 2 ) The removal of total nitrogen in ecology is completed (namely, the reflux of partial effluent water in the first-stage O pool to the first-stage A pool is meant). The first-stage A pool and the first-stage second-stage A pool have the functions that: denitrification of the anaerobism bacteria removes total nitrogen; reduces the load of the aerobic tank and prevents the sludge in the aerobic tank from expanding. Therefore, in the primary two-stage biochemical process, the anoxic is selected as the water treatment process before the aerobic. O is an aerobic tank, and is mainly used for degrading COD and ammonia nitrogen, and the reduction of COD and ammonia nitrogen is realized through the action of aerobic microorganisms in a reactor; the process is completed by nitrite bacteria and nitrate bacteria, wherein the nitrite bacteria comprise nitrite monad, nitrite helicobacter and nitrite coccus, the nitrate bacteria comprise nitrite bacillus and nitrite coccus, after the ammonia nitrogen is oxidized, nitrifying liquid flows back to an anoxic tank (namely, partial effluent in a first-stage O tank flows back to a first-stage A tank), and the total nitrogen is removed.
In the actual treatment process, the pH value of the effluent of the first-stage O pool is regulated to 7-8 by NaOH solution, and then the effluent is sent into the first-stage second-stage A pool. After the primary first-stage A/O biochemical treatment, the organic matters which can be subjected to the biochemical treatment are reduced, so that the carbon source is lack, the B/C is low, and the sludge is difficult to culture, therefore, an additional carbon source is added into the primary second-stage A pool, so that the primary second-stage A pool is better in denitrification and dephosphorization.
S4, enabling the wastewater after biochemical treatment (namely water discharged from the first-stage second-stage O pool) to enter a secondary sedimentation tank for mud-water separation, enabling part of the discharged sludge to flow back to the first-stage A pool to serve as a carbon source, directly discharging other sludge, delivering the discharged water into a coagulating sedimentation tank 1 for treatment, adding PAM and PAC into the coagulating sedimentation tank 1 for treatment, discharging sediment obtained by reaction, delivering the discharged water into an ozone pool for ozone catalytic oxidation, further opening a ring to break chains of residual organic macromolecules which are difficult to be biochemically degraded after the first-stage A/O biochemical treatment, improving the biodegradability of the water fed by the second-stage A/O biochemical treatment, improving the COD degradation efficiency of the second-stage A/O treatment unit, reducing the COD of the discharged water, and relieving the operation pressure of a subsequent treatment unit.
S5, the wastewater from the ozone pool is sent to a secondary A pool, and the sludge is difficult to culture due to lack of carbon source and low B/C, and the additional carbon source and the hydrolytic BOD in the wastewater are added into the secondary A pool as the carbon source, so that COD and total nitrogen in the wastewater can be removed efficiently; the effluent of the second-stage A pool is sent into a second-stage O pool, and is added into return sludge of an aerobic system by using a biological carrier, and the effect of removing pollutants in wastewater is improved by the adsorption effect of the biological carrier in the carbon-containing sludge and the adhesion effect of microorganisms in the activated sludge. The biological carrier is used in the secondary O pool, which is mainly because of easy implementation, lower cost and effective improvement of the biochemical effect of the wastewater.
And (3) sending the effluent from the secondary O tank into a triple sedimentation tank for mud-water separation, wherein part of the separated sludge flows back into the secondary A tank as a carbon source, the other part of sludge enters a sludge concentration tank for waiting for further treatment, and the effluent enters a coagulating sedimentation tank 2 to which PAC and PAM are added. The invention adopts a coagulating sedimentation tank 2 as terminal treatment, a coagulant is added into wastewater, the coagulant is taken as electrolyte to form a micelle in the wastewater, the micelle is electrically neutralized with colloid substances in the wastewater to form fluff particle sedimentation, and fine particles Xu Ning are destabilized and enlarged by the flocculant, so that the wastewater is sedimented. The coagulating sedimentation can remove the suspended particles with small particle size in the wastewater, and can remove chromaticity, oil content, microorganisms, organic matters and the like, thereby ensuring that the effluent finally reaches the standard. Therefore, the effluent treated by the coagulating sedimentation tank 2 is sent into a clean water tank to obtain regenerated water which is discharged up to the standard, ammonia nitrogen of the regenerated water is less than or equal to 3mg/L, total nitrogen is less than or equal to 20mg/L, CODcr is less than 50mg/L, and B/D is more than 0.4.
And (3) conveying the sludge discharged from the coagulating sedimentation tank 2 and part of sludge in the triple sedimentation tank to a sludge concentration tank, adding PAM into the concentrated sludge, conveying the sludge into a filter press for filter pressing and dehydration, conveying the obtained sludge cake into a sludge drier, and finally conveying the dried sludge. The supernatant recovered from the sludge concentration tank and the filtrate recovered from the filter press are refluxed to the comprehensive regulating tank together for regulating water quality and water quantity balance and further treatment.
Example 2
A waste water discharge process of 20 ten thousand tons of caprolactam is produced in a certain period of Shanxi, wherein an ammoximation device and an ion exchange device discharge waste water 550t/d, and other devices discharge waste water 3000t/d. The waste water discharged by the ammoximation device and the ion exchange device (B/C is 0.06) is pretreated by acidolysis reduction (namely an acid adjusting tank-acid reaction tank-alkali adjusting tank-oximation intermediate tank), the COD removal rate of the waste water reaches 38%, and the B/C is 0.45.
The waste water (B/C is 0.32) in the comprehensive regulating tank passes through the primary sedimentation tank, the hydrolytic acidification tank and the upflow anaerobic sludge tank, the COD removal rate of the waste water reaches 71.5%, the removal rate of nitrate nitrogen is 72.4%, and the B/C is 0.5.
After the wastewater treated by the double anaerobic process is subjected to primary two-stage A/O biochemical treatment, the COD removal rate of the wastewater reaches 82.5%, the removal rate of nitrate nitrogen is 83.7%, the removal rate of total nitrogen is 90.5%, and the B/C is 0.30.
The effluent after the primary two-stage A/O biochemical treatment passes through a secondary sedimentation tank, a coagulating sedimentation tank and an ozone tank, and the B/C of the effluent is 0.40.
The effluent after ozone catalytic oxidation treatment is treated by a secondary A/O biochemical treatment-a triple sedimentation tank-a coagulating sedimentation tank 2, and the COD of the final discharged wastewater is 48mg/L, BOD 5 20mg/L, ammonia nitrogen concentration of 3.0mg/L and nitrate nitrogen concentration of 15mg/L.
It is noted that the removal rate in the above example 2 only refers to the removal rate of substances contained in the inlet water and the outlet water in a certain process, and does not refer to the removal rate of substances in the whole caprolactam wastewater treatment process.
The foregoing examples merely illustrate specific embodiments of the invention, which are described in greater detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that various modifications and improvements can be made without departing from the spirit of the invention, which are within the scope of the invention.
Claims (10)
1. A caprolactam wastewater treatment method is characterized by comprising the following steps:
s1, respectively passing collected ion exchange wastewater and ammoximation wastewater through an adjusting tank, and then pretreating by adopting an acidolysis reduction process to obtain pretreated wastewater;
s2, conveying the pretreated wastewater and the wastewater of other process sections to a comprehensive regulating tank to regulate the water quality and water quantity, treating the mixed wastewater by a primary sedimentation tank, and sequentially entering a hydrolytic acidification tank and an upflow anaerobic sludge tank for double anaerobic treatment;
s3, the wastewater subjected to double anaerobic treatment enters a first-stage A/O biochemical system for treatment;
s4, sequentially treating the wastewater subjected to biochemical treatment by a secondary sedimentation tank and a coagulating sedimentation tank 1, and then entering an ozone tank for ozone catalytic oxidation;
s5, the wastewater from the ozone tank is subjected to secondary A/O biochemical treatment, enters a triple sedimentation tank, is treated by a coagulating sedimentation tank 2, and is discharged and sent into a clean water tank, so that the reclaimed water reaching the discharge standard is obtained.
2. The method for treating caprolactam wastewater according to claim 1, wherein in the step S1, the acidolysis reduction process comprises the steps of: the wastewater from the regulating tank is fed into an acid regulating tank, the pH value is regulated to 2-4 after concentrated sulfuric acid is added, and then the wastewater is fed into an acid reaction tank, and polycyclic organic matters and azo organic matters are added for acidolysis reaction, so that macromolecular substances in the wastewater are degraded; then the mixture is sent into an alkali regulating tank, the pH value is regulated to 6 to 8 by using NaOH solution, and then the mixture is sent into an oximation intermediate water tank.
3. The method for treating caprolactam wastewater according to claim 1, wherein in the step S1, the B/C value of the pretreated wastewater is 0.30-0.35, and the COD of the whole biochemical effluent is 100-130 mg/L.
4. The method for treating caprolactam wastewater according to claim 1, wherein in the hydrolysis acidification tank of the step S2, the hydrolysis acidification treatment time is 3-4 h, the temperature of the hydrolysis acidification treatment is normal temperature, and the dissolved oxygen concentration of the hydrolysis acidification treatment is less than 2mg/L.
5. The caprolactam wastewater treatment method according to claim 1, wherein in the step S3, the primary a/O biochemical system is a combination of two-stage a/O technologies, that is, the wastewater after the double anaerobic treatment is sequentially treated by a primary a tank, a primary b tank, a primary secondary a tank and a primary secondary b tank, the primary b tank and the primary b tank adopt a digestion solution reflux mode, the primary b tank effluent is added with alkali liquor to adjust the pH value to 7-8, and an external carbon source is required to be added into the primary b tank.
6. The method for treating caprolactam wastewater according to claim 1, wherein in the step S4, part of the sludge from the secondary sedimentation tank is returned to the primary tank a to serve as a carbon source, and the other part of the sludge is directly discharged.
7. The caprolactam wastewater treatment method according to claim 1, wherein in the step S5, the secondary a/O biochemical treatment process sequentially passes through a secondary a tank and a secondary O tank; the secondary A pool adopts an external carbon source and hydrolytic BOD in wastewater as carbon sources, and the secondary O pool is added with a biological carrier.
8. The caprolactam wastewater treatment method according to claim 1, wherein in the step S5, the sludge discharged from the coagulating sedimentation tank 2 and part of the sludge from the triple sedimentation tank are conveyed to a sludge concentration tank, PAM is added to the concentrated sludge, the concentrated sludge is conveyed to a filter press for press filtration and dehydration, the obtained sludge cake is conveyed to a sludge drier, and finally the dried sludge is conveyed to the outside; the supernatant recovered from the sludge concentration tank and the filtrate recovered from the filter press are refluxed to the integrated regulating tank together.
9. The caprolactam wastewater treatment method according to claim 1, wherein coagulant and flocculant are added into the coagulating sedimentation tank 1 and the coagulating sedimentation tank 2.
10. The method for treating caprolactam wastewater according to claim 8, wherein the coagulant is PAC and the flocculant is PAM.
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