Biochemical treatment method and system for cutting fluid wastewater

Abstract

The invention provides a cutting fluid wastewater biochemical treatment method and a cutting fluid wastewater biochemical treatment system. The cutting fluid wastewater biochemical treatment method comprises the following steps: treatment in an adjusting tank: guiding wastewater into the adjusting tank, and adjusting the pH value of the wastewater; hydrolysis acidification pool treatment: enabling the wastewater to enter a hydrolysis acidification pool, carrying out preliminary hydrolysis treatment through microorganisms, and decomposing macromolecular organic matters in the wastewater into micromolecular organic matters through chain scission; anaerobic tank treatment: enabling the wastewater to enter an anaerobic tank, and performing further hydrolysis treatment through microorganisms to enable macromolecular organic matters in the wastewater to be further broken and decomposed into micromolecular organic matters; treatment in a biological membrane reaction tank: enabling the wastewater to enter the biological membrane reaction tank, and consuming organic matters in the wastewater through growth and reproduction of microorganisms; treating in an anoxic tank, enabling the wastewater to enter the anoxic tank, and further degrading organic matters in the wastewater through microorganisms; treating in a biological contact oxidation pond, enabling the wastewater to enter the biological contact oxidation pond, and further degrading organic matters in the wastewater through microorganisms.

Description

Technical Field

[0001] The present application relates to the field of wastewater treatment, and in particular to a method and system for biochemical treatment of cutting fluid wastewater. Background Art

[0002] In the process of quartz production, a large amount of cutting fluid wastewater is generated. Cutting fluid wastewater has become a difficult problem in the water treatment industry due to its high COD concentration, complex composition and poor biodegradability. At present, the methods for treating cutting fluid wastewater are mainly physical and chemical methods. The specific commonly used method is the combination of Fenton pretreatment and aerobic method. Among them, the Fenton method is a chemical method; this method is that under acidic conditions, hydrogen peroxide and ferrous sulfate undergo a catalytic oxidation reaction to oxidize organic pollutants into stable inorganic compounds; this method is currently more common in treating cutting fluids, but its treatment cost is high, and chemical reagents will also produce a large amount of sludge during the reaction process; on the other hand, it will also cause secondary pollution. If there is unreacted hydrogen peroxide entering the later biochemical pool, it will cause a large number of bacterial species to die, which will cause the risk of collapse of the entire treatment system, resulting in poor system stability.

[0003] How to solve the above problems and provide a cutting fluid wastewater treatment method with better system stability is what technicians in this field need to consider. Summary of the invention

[0004] In order to solve the above problems, the embodiments of the present application provide a biochemical treatment method and a biochemical treatment system for cutting fluid wastewater, which have the characteristics of low treatment cost, stable process, simple operation, and not easy to cause secondary pollution.

[0005] The present application provides a biochemical treatment method for cutting fluid wastewater, which is characterized by comprising the following steps:

[0006] Regulating tank treatment: guide the wastewater into the regulating tank to adjust the pH value of the wastewater;

[0007] Hydrolysis acidification tank treatment: The wastewater enters the hydrolysis acidification tank and undergoes preliminary hydrolysis treatment by microorganisms, so that the macromolecular organic matter in the wastewater is broken down into small molecular organic matter;

[0008] Anaerobic tank treatment: wastewater enters the anaerobic tank, and is further hydrolyzed by microorganisms to further decompose the macromolecular organic matter in the wastewater into small molecular organic matter;

[0009] Biofilm reactor treatment: wastewater is allowed to enter the biofilm reactor, where the organic matter in the wastewater is consumed through the growth and reproduction of microorganisms;

[0010] Anoxic tank treatment: wastewater enters the anoxic tank, where microorganisms further degrade organic matter in the wastewater;

[0011] Biological contact oxidation tank treatment: The wastewater enters the biological contact oxidation tank, where microorganisms further degrade the organic matter in the wastewater.

[0012] In one embodiment, in the regulating tank treatment step, the pH value of the wastewater is adjusted to a range of 6-7.

[0013] In one embodiment, in the hydrolysis acidification tank treatment step, the pH value of the wastewater is controlled to be in the range of 5.5-7, the temperature range is 10° C.-30° C., and the hydraulic retention time is 9.5-10.5 hours.

[0014] In one embodiment, in the anaerobic tank treatment step, the pH value of the wastewater is controlled to be in the range of 7-8, the temperature is in the range of 10° C.-30° C., and the hydraulic retention time is 19.5-20.5 hours.

[0015] In one embodiment, in the biofilm reaction tank treatment step, the pH value of the wastewater is controlled to be in the range of 7.5-8.5, the temperature range is 10°C-30°C, the dissolved oxygen range is 2mg / L-4mg / L, and the hydraulic retention time is 7.5-8.5 hours.

[0016] In one embodiment, in the biofilm reaction tank treatment step, the ratio of carbon to nitrogen in the wastewater is controlled to be 100:5; the biofilm reaction tank is filled with filler, the volume of the filler accounts for one quarter of the volume of the biofilm reaction tank, and the filler is used to carry microorganisms.

[0017] In one embodiment, in the anoxic tank treatment step, the pH of the wastewater is controlled at 7-8, the dissolved oxygen is controlled at 1 mg / L-2 mg / L, the temperature is controlled in the range of 10°C-30°C, and the hydraulic retention time is 5.5-6.5 hours.

[0018] In one embodiment, in the biological contact oxidation pond treatment step, the pH of the wastewater is controlled at 7.5-8.5, the dissolved oxygen is controlled at 2 mg / L-4 mg / L, the temperature is controlled in the range of 10°C-30°C, and the hydraulic retention time is 3.5 hours-4.5 hours.

[0019] In one embodiment, in the hydrolysis acidification tank treatment step and the anaerobic tank treatment step, the liquid and sludge of the wastewater are controlled to be in a stirred and mixed state; the anaerobic tank treatment step and the biofilm reaction tank treatment step also include a first sedimentation, and the wastewater after the anaerobic tank treatment step is subjected to the first sedimentation to separate the sludge and the supernatant in the wastewater, and the separated supernatant enters the biofilm reaction tank treatment step for further treatment; after the biological contact oxidation tank treatment step, it also includes a second sedimentation, and the wastewater after the biological contact oxidation tank treatment step is subjected to the second sedimentation to separate the sludge and the supernatant in the wastewater, and the separated part of the sludge is returned to the biofilm reaction tank treatment step.

[0020] The embodiment of the present application also provides a biochemical treatment system for cutting fluid wastewater, which is used to implement the biochemical treatment method for cutting fluid wastewater as described in any one of the aforementioned embodiments.

[0021] It can be understood that by controlling the parameters of each stage of the biochemical treatment process of cutting fluid wastewater through the biochemical treatment system and the biochemical treatment method of cutting fluid wastewater of the present application, the stable operation of the biochemical treatment of cutting fluid wastewater can be achieved. When the COD of cutting fluid wastewater is about 1800mg / L, through the biochemical treatment system and the biochemical treatment method of cutting fluid wastewater of the present application, the water quality after wastewater treatment can reach COD≤300mg / L, meeting the national industrial wastewater discharge level 3 standard. The biochemical treatment system and the biochemical treatment method of cutting fluid wastewater have the characteristics of low treatment cost, stable process, simple operation, and not easy to produce secondary pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the structure of the biochemical treatment system for cutting fluid wastewater provided in an embodiment of the present application.

[0023] Figure 2 A schematic flow chart of the biochemical treatment method for cutting fluid wastewater provided in an embodiment of the present application. DETAILED DESCRIPTION

[0024] The following description will refer to the accompanying drawings to more fully describe the content of the present application. Shown in the accompanying drawings are exemplary embodiments of the present application. However, the present application can be implemented in many different forms and should not be construed as being limited to the exemplary embodiments set forth herein. These exemplary embodiments are provided to make the present application thorough and complete, and to fully convey the scope of the present application to those skilled in the art. Similar reference numerals represent identical or similar components.

[0025] The terms used herein are only used for the purpose of describing specific exemplary embodiments and are not intended to limit the present application. As used herein, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to also include the plural forms. In addition, when used herein, "including" and / or "comprising" and / or "having", integers, steps, operations, components and / or components, but do not exclude the existence or addition of one or more other features, regions, integers, steps, operations, components and / or groups thereof.

[0026] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill in the art to which this application belongs. In addition, unless explicitly defined herein, terms such as those defined in general dictionaries should be interpreted as having a meaning consistent with their meaning in the relevant technology and the content of this application, and will not be interpreted as an idealized or overly formal meaning.

[0027] Usually, a large amount of cutting fluid wastewater is generated during the quartz production process. Cutting fluid wastewater has become a difficult problem in the water treatment industry due to its high COD concentration, complex composition and poor biodegradability. At present, the methods for treating cutting fluid wastewater are mainly physical and chemical methods. The specific commonly used method is the combination of Fenton pretreatment and aerobic method. Among them, the Fenton method is a chemical method; this method is that under acidic conditions, hydrogen peroxide and ferrous sulfate undergo a catalytic oxidation reaction to oxidize organic pollutants into stable inorganic compounds; this method is currently more common in treating cutting fluids, but its treatment cost is high, and chemical reagents will also produce a large amount of sludge during the reaction process; on the other hand, it will also cause secondary pollution. If there is unreacted hydrogen peroxide entering the later biochemical pool, it will cause a large number of bacterial species to die, which will cause the risk of collapse of the entire treatment system, resulting in poor system stability.

[0028] Correspondingly, the present application provides a biochemical treatment method for cutting fluid wastewater and a biochemical treatment system for cutting fluid wastewater. The biochemical treatment method for cutting fluid wastewater includes the following steps: treatment in a regulating tank, guiding the wastewater into the regulating tank, and adjusting the pH value of the wastewater; treatment in a hydrolysis acidification tank, allowing the wastewater to enter the hydrolysis acidification tank, and performing preliminary hydrolysis treatment by microorganisms, so that the macromolecular organic matter in the wastewater is broken and decomposed into small molecular organic matter; treatment in an anaerobic tank, allowing the wastewater to enter the anaerobic tank, and further hydrolyzing treatment by microorganisms so that the macromolecular organic matter in the wastewater is further broken and decomposed into small molecular organic matter; treatment in a biofilm reaction tank, allowing the wastewater to enter the biofilm reaction tank, and consuming the organic matter in the wastewater through the growth and reproduction of microorganisms; treatment in an anoxic tank, allowing the wastewater to enter the anoxic tank, and further degrading the organic matter in the wastewater by microorganisms; treatment in a biological contact oxidation tank, allowing the wastewater to enter the biological contact oxidation tank, and further degrading the organic matter in the wastewater by microorganisms.

[0029] Furthermore, by controlling the parameters of each stage of the biochemical treatment process of cutting fluid wastewater through the biochemical treatment system and the biochemical treatment method of cutting fluid wastewater of the present application, the stable operation of the biochemical treatment of cutting fluid wastewater can be achieved. When the COD of cutting fluid wastewater is about 1800mg / L, through the biochemical treatment system and the biochemical treatment method of cutting fluid wastewater of the present application, the water quality after wastewater treatment can reach COD≤300mg / L, meeting the national industrial wastewater discharge level 3 standard. The biochemical treatment system and the biochemical treatment method of cutting fluid wastewater have the characteristics of low treatment cost, stable process, simple operation, and not easy to produce secondary pollution.

[0030] Those skilled in the art will understand that "MBBR" is the abbreviation of Moving Bed Biofilm Reactor, and MBBR pool refers to a water treatment pool that uses a moving bed biofilm reactor. In the treatment of cutting fluid wastewater, the MBBR pool adds suspended fillers in the reactor, and microorganisms attach to the surface of the fillers to form a biofilm. The fillers are made to flow through aeration, which enhances the contact between wastewater and biofilm, thereby improving the treatment efficiency.

[0031] As those skilled in the art can understand, "COD" refers to Chemical Oxygen Demand. COD is an important indicator for measuring the organic content in water. A high COD value indicates a high concentration of organic pollutants in wastewater, which has a great impact on the environment.

[0032] As those skilled in the art will understand, "SS" refers to suspended solids. SS refers to undissolved solid particles in wastewater, including metal chips, silt, etc. High SS can cause turbidity in the water and affect the operation of treatment equipment.

[0033] The specific implementation methods of the present application are further described in detail below with reference to the accompanying drawings.

[0034] like Figure 1 As shown, an embodiment of the present application provides a cutting wastewater treatment system, including a regulating tank, a hydrolysis acidification tank, an anaerobic tank, a first sedimentation tank, a biofilm reactor tank (MBBR tank), an anoxic tank, a biological contact oxidation tank, a second sedimentation tank, a drainage tank and a sludge thickening tank.

[0035] In one embodiment, the regulating tank is used to make the wastewater quality uniform and adjust the pH value of the wastewater. For example, the pH value of the wastewater can be adjusted to 6-7.

[0036] In one embodiment, according to the process sequence of the cutting wastewater treatment system for treating wastewater, the hydrolysis acidification tank is located at the subsequent step of the regulating tank. The microorganisms in the hydrolysis acidification tank are domesticated and matured through a step-by-step domestication method and then begin to take in water, and the wastewater flows to the hydrolysis acidification tank through the overflow weir.

[0037] It is understandable that in the hydrolysis acidification tank, the macromolecular organic matter in the wastewater is hydrolyzed, and the long-chain macromolecular organic matter that is difficult to degrade is broken into small-molecule organic matter that is easy to decompose, which is used to improve the biodegradability of the wastewater. During the hydrolysis process in the hydrolysis acidification tank, the pH range of the wastewater needs to be controlled at 5.5-7, the temperature range needs to be 10℃-30℃, the sludge and water need to be stirred evenly, and the hydraulic retention time is maintained at about 10 hours.

[0038] In one embodiment, according to the process sequence of the cutting wastewater treatment system for treating wastewater, the anaerobic tank is located at the subsequent step of the hydrolysis acidification tank. The microorganisms in the anaerobic tank are domesticated and matured by a step-by-step domestication method and then begin to enter the water. The wastewater after hydrolysis and acidification in the hydrolysis acidification tank enters the anaerobic tank. The anaerobic tank has high impact load resistance and a stable reaction system.

[0039] It is understandable that in the anaerobic tank, the long-chain organic matter that has not been completely hydrolyzed continues to break the chain and further hydrolyzes into small molecular organic matter. The organic nitrogen compounds in the cutting fluid wastewater hydrolyze into free nitrogen, further improving the biodegradability of the wastewater. During the hydrolysis process in the anaerobic tank, a part of the COD is degraded by anaerobic microorganisms, so that the water quality of the wastewater is initially improved, so that the effluent can meet the water inlet requirements of the subsequent biofilm reactor (MBBR tank). During the hydrolysis process in the anaerobic tank, the pH range of the wastewater needs to be controlled at 7-8, the temperature range is 10℃-30℃, the sludge and water are stirred more evenly, and the hydraulic retention time is 20 hours.

[0040] In one embodiment, according to the process sequence of the cutting wastewater treatment system for treating wastewater, the first sedimentation tank is located at the subsequent step of the anaerobic tank. The effluent of the anaerobic tank enters the sedimentation tank, and the sludge is separated from the supernatant. A part of the sludge flows to the front hydrolysis acidification tank to ensure that there is enough sludge concentration in the system, and the excess sludge is discharged into the sludge concentration tank for treatment.

[0041] In one embodiment, according to the process sequence of the cutting wastewater treatment system for treating wastewater, the biofilm reactor (MBBR) tank is located at the subsequent step of the sedimentation tank. The microorganisms in the MBBR tank need to be gradually domesticated and matured before water can be added, and the supernatant in the sedimentation tank overflows from the overflow weir to the MBBR tank.

[0042] It is understandable that fillers are added to the MBBR pool, and the filler part accounts for 1 / 4 of the volume of the MBBR pool. Microorganisms grow fixedly on the fillers, relying on organic matter in the wastewater as nutrients for growth and reproduction. The purpose of purifying water quality is achieved by consuming organic matter in the wastewater through the growth and reproduction of microorganisms. In the MBBR pool, the pH range needs to be controlled at 7.5-8.5, the temperature range is 10℃-30℃, the C:N (carbon-nitrogen ratio) ratio is maintained at 100:5, the dissolved oxygen range is 2mg / L-4mg / L, and the hydraulic retention time is about 8 hours.

[0043] In one embodiment, according to the process sequence of the cutting wastewater treatment system for treating wastewater, the anoxic tank is located at the subsequent step of the MBBR tank. The microorganisms in the anoxic tank are domesticated and matured through a step-by-step domestication method and then begin to take in water. The wastewater treated in the MBBR tank overflows from the overflow weir to the anoxic tank.

[0044] It is understandable that the treatment in the anoxic tank can further reduce the COD concentration in the wastewater, hydrolyze a small amount of remaining difficult-to-degrade pollutants, and improve the biodegradability of the wastewater. In the anoxic tank, the pH of the wastewater needs to be controlled at 7-8, the dissolved oxygen is controlled at 1mg / L-2mg / L, the temperature is controlled in the range of 10℃-30℃, and the hydraulic retention time is about 6 hours.

[0045] In one embodiment, according to the process sequence of the cutting wastewater treatment system for treating wastewater, the biological contact oxidation pool is located at the subsequent step of the anoxic pool. The microorganisms in the biological contact oxidation pool are domesticated and matured through a step-by-step domestication method and then begin to take in water.

[0046] It is understandable that the microorganisms after the anoxic reaction enter the biological contact oxidation tank, and the residual COD is deeply treated by the microorganisms in the contact oxidation tank, the ammonia nitrogen in the cutting fluid wastewater is degraded, and the suspended solids in the wastewater are reduced. Ensure that the SS, COD concentration and ammonia nitrogen concentration can meet the discharge standards. In the biological contact oxidation tank, the temperature range of the wastewater needs to be controlled at 10℃-30℃, the pH of the wastewater is 7.5-8.5 (the treatment effect is better within this pH range), the hydraulic retention time is about 4 hours, and the dissolved oxygen range is 2mg / L-4mg / L.

[0047] In one embodiment, according to the process sequence of the cutting wastewater treatment system for treating wastewater, the second sedimentation tank is located at the subsequent step of the biological contact oxidation tank. It can be understood that by setting up the second sedimentation tank, the mud and water in the wastewater are separated, and the separated supernatant flows from the overflow weir to the drainage tank for external discharge; at the same time, part of the sludge in the second sedimentation tank flows back to the front end (MBBR tank) structure to maintain a sufficient sludge concentration in the structure, and the excess sludge is discharged into the sludge concentration tank for treatment.

[0048] Further integration Figure 2 As shown, the embodiment of the present application also provides a biochemical treatment method for cutting fluid wastewater, which includes the following steps:

[0049] S1. Treatment in equalization tank: guide the wastewater into the equalization tank to adjust the pH value of the wastewater; specifically, it can be adjusted to slightly acidic.

[0050] In one embodiment, in the regulating tank treatment step, the pH value of the wastewater is adjusted to a range of 6-7.

[0051] In this embodiment, the pH value of the wastewater can be adjusted to 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, or 6.9.

[0052] S2. Hydrolysis and acidification tank treatment: The wastewater enters the hydrolysis and acidification tank and undergoes preliminary hydrolysis treatment by microorganisms, so that the large molecular organic matter in the wastewater is broken down into small molecular organic matter.

[0053] In one embodiment, in the hydrolysis acidification tank treatment step, the pH value of the wastewater is controlled to be in the range of 5.5-7, the temperature range is 10° C.-30° C., and the hydraulic retention time is 9.5-10.5 hours.

[0054] In this embodiment, the pH value of the wastewater can be specifically controlled to be 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, and 6.9; the temperature can be specifically 11°C, 12°C, 13°C, 14°C, 15°C, 16°C, 17°C, 18°C, 19°C, 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, and 30°C; and the hydraulic retention time can be specifically 9.6 hours, 9.7 hours, 9.8 hours, 9.9 hours, 10 hours, 10.1 hours, 10.2 hours, 10.3 hours, and 10.4 hours.

[0055] It can be understood that the pH value in the hydrolysis acidification tank treatment step is controlled to be slightly acidic, not less than 5.5, not higher than 7, and generally controlled at about 6 to 7. The hydrolysis acidification tank treatment step is mainly an anaerobic hydrolysis reaction.

[0056] In one embodiment, in the hydrolysis acidification tank treatment step, the liquid and sludge of the wastewater are controlled to be in a stirring and mixing state.

[0057] It can be understood that the microorganisms in the hydrolysis acidification tank are domesticated and matured through a step-by-step domestication method and then begin to enter the water, and the wastewater flows to the hydrolysis acidification tank through the overflow weir. In this process, the macromolecular organic matter in the wastewater is hydrolyzed, and the macromolecular long-chain organic matter that is difficult to degrade is broken into small molecular organic matter that is easily degradable, which is used to improve the biodegradability of the wastewater.

[0058] S3. Anaerobic tank treatment: The wastewater enters the anaerobic tank and is further hydrolyzed by microorganisms to further decompose the macromolecular organic matter in the wastewater into small molecular organic matter.

[0059] In one embodiment, in the anaerobic tank treatment step, the pH value of the wastewater is controlled to be in the range of 7-8, the temperature is in the range of 10° C.-30° C., and the hydraulic retention time is 19.5-20.5 hours.

[0060] In this embodiment, the pH value of the wastewater can be specifically controlled to be 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, and 7.9; the temperature value can be specifically 11°C, 12°C, 13°C, 14°C, 15°C, 16°C, 17°C, 18°C, 19°C, 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, and 30°C; and the hydraulic retention time can be specifically 19.6 hours, 19.7 hours, 19.8 hours, 19.9 hours, 20 hours, 20.1 hours, 20.2 hours, 20.3 hours, and 20.4 hours.

[0061] It can be understood that the pH of the anaerobic tank treatment stage is weakly alkaline, and the pH value is preferably between 7 and 8.

[0062] In one embodiment, in the anaerobic tank treatment step, the liquid and sludge of the wastewater are controlled to be in a stirred and mixed state.

[0063] It is understandable that the microorganisms in the anaerobic tank are domesticated and matured through a step-by-step domestication method and then begin to take in water. The wastewater after hydrolysis and acidification in the hydrolysis and acidification tank enters the anaerobic tank. The anaerobic tank has high resistance to shock loads and a stable reaction system. In this process, the long-chain organic matter that has not been completely hydrolyzed continues to break the chain and is further hydrolyzed into small molecular organic matter. The organic nitrogen compounds in the cutting fluid wastewater are hydrolyzed into free nitrogen, further improving the biodegradability of the wastewater. During the hydrolysis process in the anaerobic tank, a portion of the COD is degraded by anaerobic microorganisms, which preliminarily improves the quality of the wastewater and enables the effluent to meet the inlet requirements of the subsequent biofilm reactor (MBBR) tank.

[0064] S4. Biofilm reactor (MBBR) treatment: The wastewater is allowed to enter the biofilm reactor, where the organic matter in the wastewater is consumed through the growth and reproduction of microorganisms.

[0065] In one embodiment, in the biofilm reaction tank treatment step, the pH value of the wastewater is controlled to be in the range of 7.5-8.5, the temperature range is 10°C-30°C, the dissolved oxygen range is 2mg / L-4mg / L, and the hydraulic retention time is 7.5-8.5 hours.

[0066] In this embodiment, the pH value of the wastewater can be specifically controlled to be 7.6, 7.7, 7.8, 7.9, 8.0, 8.1, 8.2, 8.3, and 8.4, and the temperature can be specifically 11°C, 12°C, 13°C, 14°C, 15°C, 16°C, 17°C, 18°C, 19°C, 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, and 30°C, and the dissolved oxygen range is 2.1 mg / L, 2.2 mg / L, 2.3 mg / L, and 2.4 mg / L , 2.5mg / L, 2.6mg / L, 2.7mg / L, 2.8mg / L, 2.9mg / L, 3.0mg / L, 3.1mg / L, 3.2mg / L, 3.3mg / L, 3.4mg / L, 3.5mg / L, 3.6mg / L, 3.7mg / L, 3.8mg / L, 3.9mg / L, the hydraulic retention time can also be 7.6 hours, 7.7 hours, 7.8 hours, 7.9 hours, 8 hours, 8.1 hours, 8.2 hours, 8.3 hours, 8.4 hours.

[0067] In one embodiment, in the biofilm reaction tank treatment step, the ratio of carbon to nitrogen (C:N) in the wastewater is controlled to be 100:5; the biofilm reaction tank is filled with filler, the volume of the filler accounts for one quarter of the volume of the biofilm reaction tank, and the filler is used to carry microorganisms to enable them to grow fixedly.

[0068] It is understandable that the microorganisms in the MBBR pool need to be gradually domesticated and matured before they can enter the water. The supernatant in the sedimentation tank overflows from the overflow weir to the MBBR pool. Fillers are added to the MBBR pool, and the filler part accounts for 1 / 4 of the volume of the MBBR pool. Microorganisms grow fixedly on the fillers, relying on organic matter in the wastewater as nutrients for growth and reproduction. The purpose of purifying water quality is achieved by consuming organic matter in the wastewater through the growth and reproduction of microorganisms.

[0069] In one embodiment, the anaerobic tank treatment step and the biofilm reaction tank treatment step also include a first sedimentation, and the wastewater after the anaerobic tank treatment step is subjected to the first sedimentation to separate the sludge and supernatant in the wastewater, and the separated supernatant enters the biofilm reaction tank treatment step for further treatment.

[0070] In this embodiment, the effluent from the anaerobic tank enters the sedimentation tank, the sludge is separated from the supernatant, and part of the sludge flows to the front hydrolysis acidification tank to ensure that there is sufficient sludge concentration in the system, and the excess sludge is discharged into the sludge concentration tank for treatment.

[0071] S5. Anoxic tank treatment: The wastewater is allowed to enter the anoxic tank, where the organic matter in the wastewater is further degraded by microorganisms.

[0072] In one embodiment, in the anoxic tank treatment step, the pH of the wastewater is controlled at 7-8, the dissolved oxygen is controlled at 1 mg / L-2 mg / L, the temperature is controlled in the range of 10°C-30°C, and the hydraulic retention time is 5.5-6.5 hours.

[0073] In this embodiment, the pH value of the wastewater can be specifically controlled to be 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, and 7.9; the temperature can be specifically 11°C, 12°C, 13°C, 14°C, 15°C, 16°C, 17°C, 18°C, 19°C, 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, and 30°C; and the hydraulic retention time can be specifically 5.6 hours, 5.7 hours, 5.8 hours, 5.9 hours, 6 hours, 6.1 hours, 6.2 hours, 6.3 hours, and 6.4 hours.

[0074] It can be understood that the microorganisms in the anoxic pool are domesticated and matured through a step-by-step domestication method and then begin to enter the water. The wastewater treated by the MBBR pool overflows from the overflow weir to the anoxic pool. The treatment in the anoxic pool can further reduce the COD concentration in the wastewater, hydrolyze a small amount of remaining difficult-to-degrade pollutants, and improve the biodegradability of the wastewater.

[0075] S6. Biological contact oxidation tank treatment: The wastewater is allowed to enter the biological contact oxidation tank, where the organic matter in the wastewater is further degraded by microorganisms.

[0076] In one embodiment, in the biological contact oxidation pond treatment step, the pH of the wastewater is controlled at 7.5-8.5, the dissolved oxygen is controlled at 2 mg / L-4 mg / L, the temperature is controlled in the range of 10°C-30°C, and the hydraulic retention time is 3.5-4.5 hours.

[0077] In this embodiment, the pH value of the wastewater can be specifically controlled to be 7.6, 7.7, 7.8, 7.9, 8.0, 8.1, 8.2, 8.3, and 8.4, and the temperature can be specifically 11°C, 12°C, 13°C, 14°C, 15°C, 16°C, 17°C, 18°C, 19°C, 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, and 30°C, and the dissolved oxygen range is 2.1 mg / L, 2.2 mg / L, 2.3 mg / L, and 2.4 mg / L , 2.5mg / L, 2.6mg / L, 2.7mg / L, 2.8mg / L, 2.9mg / L, 3.0mg / L, 3.1mg / L, 3.2mg / L, 3.3mg / L, 3.4mg / L, 3.5mg / L, 3.6mg / L, 3.7mg / L, 3.8mg / L, 3.9mg / L, the hydraulic retention time can also be 3.6 hours, 3.7 hours, 3.8 hours, 3.9 hours, 4 hours, 4.1 hours, 4.2 hours, 4.3 hours, 4.4 hours.

[0078] It is understandable that the microorganisms in the biological contact oxidation pool are domesticated and matured through a step-by-step domestication method and then begin to enter the water. The microorganisms after the anoxic reaction enter the biological contact oxidation pool, and the residual COD is deeply treated by the microorganisms in the contact oxidation pool, the ammonia nitrogen in the cutting fluid wastewater is degraded, and the suspended solids in the wastewater are reduced. Ensure that the SS, COD concentration and ammonia nitrogen concentration can meet the discharge standards.

[0079] In one embodiment, a second sedimentation is further included after the biological contact oxidation tank treatment step. The wastewater after the biological contact oxidation tank treatment step is subjected to the second sedimentation to separate the sludge from the supernatant in the wastewater, and the separated part of the sludge is returned to the biofilm reaction tank treatment step.

[0080] It can be understood that by setting up a second sedimentation tank, the mud and water in the wastewater are separated, and the separated supernatant flows from the overflow weir to the drainage tank for discharge; at the same time, part of the sludge in the second sedimentation tank flows back to the front end (MBBR tank) structure to maintain a sufficient sludge concentration in the structure, and the excess sludge is discharged into the sludge concentration tank for treatment.

[0081] Embodiment 1:

[0082] The cutting fluid is mixed with water to simulate the cutting fluid wastewater, and the COD of the simulated cutting fluid wastewater is controlled at about 1000 mg / L;

[0083] Inoculate the domesticated strains and perform enrichment culture;

[0084] The biochemical treatment method and biochemical treatment system for cutting fluid wastewater provided in the embodiment of the present application are used to treat simulated cutting fluid wastewater, and various parameters are strictly controlled;

[0085] The effluent quality of each process section of the wastewater was tested, and the test results are shown in Table 1;

[0086] Table 1

[0087]

[0088] Embodiment 2:

[0089] The cutting fluid is mixed with water to simulate the cutting fluid wastewater, and the COD of the simulated cutting fluid wastewater is controlled at about 1500 mg / L;

[0090] Inoculate the domesticated strains and perform enrichment culture;

[0091] The simulated wastewater was treated as in the above process, and each parameter was strictly controlled;

[0092] The effluent quality of each process section of the wastewater was tested, and the test results are shown in Table 2;

[0093] Table 2

[0094]

[0095] Embodiment 3:

[0096] The cutting fluid is mixed with water to simulate the cutting fluid wastewater, and the COD of the simulated cutting fluid wastewater is controlled at about 1800 mg / L;

[0097] Inoculate the domesticated strains and perform enrichment culture;

[0098] The simulated wastewater was treated as in the above process, and each parameter was strictly controlled;

[0099] The water quality of each process effluent section of the wastewater was tested, and the test results are shown in Table 3;

[0100] Table 3

[0101]

[0102] Furthermore, by controlling the parameters of each stage of the biochemical treatment process of cutting fluid wastewater through the biochemical treatment system and the biochemical treatment method of cutting fluid wastewater of the present application, the stable operation of the biochemical treatment of cutting fluid wastewater can be achieved. When the COD of cutting fluid wastewater is about 1800mg / L, through the biochemical treatment system and the biochemical treatment method of cutting fluid wastewater of the present application, the water quality after wastewater treatment can reach COD≤300mg / L, meeting the national industrial wastewater discharge level 3 standard. The biochemical treatment system and the biochemical treatment method of cutting fluid wastewater have the characteristics of low treatment cost, stable process, simple operation, and not easy to produce secondary pollution.

[0103] It can be understood that, through the biochemical treatment system and biochemical treatment method of cutting fluid wastewater of the present application, microbial method is used to treat cutting fluid wastewater. Compared with the traditional Fenton method, the biochemical method does not use strong oxidants in the entire treatment process of wastewater, and will not affect the subsequent treatment of wastewater. The system is relatively stable under long-term operation. In addition, the chemical agents in the traditional method are generally expensive, and a large amount of by-products will be produced after the chemical reaction, which is easy to cause secondary pollution; while the biochemical treatment system and biochemical treatment method of cutting fluid wastewater of the present application do not use these chemical agents to treat wastewater, which is low-cost and has no secondary pollution.

[0104] In the above, the specific embodiments of the present application are described with reference to the accompanying drawings. However, those skilled in the art will appreciate that various changes and substitutions may be made to the specific embodiments of the present application without departing from the scope of the present application. These changes and substitutions are all within the scope defined by the present application.

Claims

1. A biochemical treatment method for cutting fluid wastewater, characterized in that: The steps include: Regulating tank treatment: guide the wastewater into the regulating tank to adjust the pH value of the wastewater; Hydrolysis acidification tank treatment: The wastewater enters the hydrolysis acidification tank and undergoes preliminary hydrolysis treatment by microorganisms, so that the macromolecular organic matter in the wastewater is broken down into small molecular organic matter; Anaerobic tank treatment: The wastewater enters the anaerobic tank and is further hydrolyzed by microorganisms to further decompose the macromolecular organic matter in the wastewater into small molecular organic matter; Biofilm reactor treatment: wastewater is allowed to enter the biofilm reactor, where the organic matter in the wastewater is consumed through the growth and reproduction of microorganisms; Anoxic tank treatment: wastewater enters the anoxic tank, where microorganisms further degrade organic matter in the wastewater; Biological contact oxidation tank treatment: The wastewater enters the biological contact oxidation tank, where microorganisms further degrade the organic matter in the wastewater.

2. The biochemical treatment method for cutting fluid wastewater according to claim 1, characterized in that: In the regulating tank treatment step, the pH value of the wastewater is adjusted to a range of 6-7.

3. The biochemical treatment method for cutting fluid wastewater according to claim 1, characterized in that: In the hydrolysis acidification tank treatment step, the pH value of the wastewater is controlled to be in the range of 5.5-7, the temperature range is 10° C.-30° C., and the hydraulic retention time is 9.5-10.5 hours.

4. The biochemical treatment method for cutting fluid wastewater according to claim 1, characterized in that: In the anaerobic tank treatment step, the pH value of the wastewater is controlled to be in the range of 7-8, the temperature range is 10° C.-30° C., and the hydraulic retention time is 19.5-20.5 hours.

5. The biochemical treatment method for cutting fluid wastewater according to claim 1, characterized in that: In the biofilm reaction tank treatment step, the pH value of the wastewater is controlled to be in the range of 7.5-8.5, the temperature range is 10°C-30°C, the dissolved oxygen range is 2mg / L-4mg / L, and the hydraulic retention time is 7.5-8.5 hours.

6. The biochemical treatment method for cutting fluid wastewater according to claim 5, characterized in that: In the biofilm reaction tank treatment step, the ratio of carbon element to nitrogen element in the wastewater is controlled to be 100:5; the biofilm reaction tank is filled with filler, the volume of the filler accounts for one quarter of the volume of the biofilm reaction tank, and the filler is used to carry microorganisms.

7. The biochemical treatment method for cutting fluid wastewater according to claim 1, characterized in that: In the anoxic tank treatment step, the pH of the wastewater is controlled at 7-8, the dissolved oxygen is controlled at 1 mg / L-2 mg / L, the temperature is controlled in the range of 10°C-30°C, and the hydraulic retention time is 5.5-6.5 hours.

8. The biochemical treatment method for cutting fluid wastewater according to claim 1, characterized in that: In the biological contact oxidation pond treatment step, the pH of the wastewater is controlled at 7.5-8.5, the dissolved oxygen is controlled at 2 mg / L-4 mg / L, the temperature is controlled in the range of 10°C-30°C, and the hydraulic retention time is 3.5-4.5 hours.

9. The biochemical treatment method for cutting fluid wastewater according to claim 1, characterized in that: In the hydrolysis acidification tank treatment step and the anaerobic tank treatment step, the liquid and sludge of the wastewater are controlled to be in a stirred and mixed state; the anaerobic tank treatment step and the biofilm reaction tank treatment step also include a first sedimentation, and the wastewater after the anaerobic tank treatment step is subjected to the first sedimentation to separate the sludge and the supernatant in the wastewater, and the separated supernatant enters the biofilm reaction tank treatment step for further treatment; after the biological contact oxidation tank treatment step, it also includes a second sedimentation, and the wastewater after the biological contact oxidation tank treatment step is subjected to the second sedimentation to separate the sludge and the supernatant in the wastewater, and the separated part of the sludge is returned to the biofilm reaction tank treatment step.

10. A biochemical treatment system for cutting fluid wastewater, characterized in that: The method is used to implement the biochemical treatment method of cutting fluid wastewater as described in any one of claims 1 to 9.

Images