A method and system for treating machining wastewater

Abstract

The application discloses a machining wastewater treatment method, and relates to wastewater treatment technology. The method comprises the following steps: performing air floatation and coagulation treatment on machining wastewater to separate solid and liquid in the machining wastewater, and obtaining pretreated wastewater; and sequentially performing cyclic anaerobic decomposition and cyclic facultative decomposition on the pretreated wastewater to purify organic matters in the pretreated wastewater, and obtaining water after pre-purification. The application further discloses a machining wastewater treatment system. The application adopts water circulation in the anaerobic and oxidation processes, can greatly improve the treatment speed of organic matter decomposition, and can further improve the treatment capacity of the treatment system for wastewater.

Description

Technical Field

[0001] This invention relates to wastewater treatment technology, and more specifically, to a method and system for treating machining wastewater. Background Technology

[0002] The machining wastewater generated during the production and processing of vehicle parts such as flywheels mainly consists of cleaning wastewater and painting wastewater. This wastewater contains a significant amount of impurities and oil, thus requiring treatment before discharge. Current machining wastewater treatment processes involve adding flocculants to the wastewater and then sequentially passing it through air flotation, anaerobic digestion, and oxidation processes to achieve solid-liquid separation and organic matter decomposition, resulting in purified water. After sedimentation and separation of water and sludge, the water can be discharged. In existing technologies, the anaerobic and oxidation processes involve discharging wastewater from the previous process into anaerobic and oxidation tanks, where bacteria capture and decompose organic matter. The decomposition of organic matter generates gas, which agitates the water, preventing the organic matter from remaining statically suspended in a fixed position. However, this method involves passive water flow, which is not only slow, but also results in more pronounced stratification as the water remains in the pool for longer. This leads to uneven distribution of organic matter, poor decomposition efficiency, and ultimately excessively long anaerobic or oxidation time, making it difficult to improve the system's wastewater treatment capacity. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to address the shortcomings of the prior art by providing a method and system for treating machining wastewater, which greatly improves the treatment speed of organic matter decomposition and increases the treatment capacity of wastewater.

[0004] The present invention discloses a method for treating machining wastewater, comprising: subjecting the machining wastewater to air flotation coagulation treatment to achieve solid-liquid separation and obtain pretreated wastewater; and sequentially treating the pretreated wastewater by circulating anaerobic decomposition and circulating facultative anaerobic decomposition to purify the organic matter in the pretreated wastewater to obtain pre-purified water.

[0005] Preferably, the air flotation coagulation treatment method is as follows: the machining wastewater is input into an equalization tank for pH adjustment, and after the pH value of the machining wastewater is adjusted to the set target pH value, the pH-adjusted machining wastewater is input into a flocculation tank, and a set amount of flocculant is added according to the water volume in the flocculation tank. After stirring evenly and reacting for a set reaction time period, the machining wastewater reacting with the flocculant is input into an air flotation tank for air flotation treatment for a set air flotation time period to obtain the pretreated wastewater.

[0006] Preferably, the circulating anaerobic decomposition method specifically involves: setting up two anaerobic tanks and arranging anaerobic bacteria in the middle of the anaerobic tanks; setting up a circulating water path between the two anaerobic tanks; inputting the pretreated wastewater into the two anaerobic tanks; setting the water circulation speed and circulation time period according to the water volume of the anaerobic tanks; controlling the water circulation in the two anaerobic tanks according to the water circulation speed to form a circulation flow in the two anaerobic tanks; stopping the water circulation in the anaerobic tanks when the actual water circulation time in the anaerobic tanks reaches the circulation time period; and then transporting the anaerobic pretreated wastewater to the next process.

[0007] Preferably, after the water circulation in the anaerobic tank stops, the wastewater in both anaerobic tanks is allowed to stand for a set first settling time period before the pretreated wastewater after anaerobic treatment is transported to the next process.

[0008] Preferably, the cyclic anaerobic decomposition method specifically involves: setting up an anaerobic tank and a first oxidation tank, arranging the bacterial community in the middle of the tanks, and setting up a circulating water path between the anaerobic tank and the first oxidation tank; inputting the pretreated wastewater after anaerobic treatment into the anaerobic tank and the first oxidation tank, and controlling the water in the tanks to circulate at a set initial circulation flow rate according to the water volume in these two tanks; monitoring the water transparency in the first oxidation tank, and controlling the current circulation flow rate of the water body according to the water transparency; when the water transparency reaches a set transparency threshold, stopping the water circulation between the anaerobic tank and the first oxidation tank to obtain the oxidized water body.

[0009] Preferably, the current circulation velocity of the water body is calculated using the following formula: , In the formula, V1 is the current circulating velocity of the water body; V0 is the initial circulating velocity; TDS MAX TDS1 represents the transparency value of the pretreated wastewater after anaerobic treatment, which is input into the facultative anaerobic tank and the first oxidation tank; TDS0 represents the water transparency value monitored in the first oxidation tank; and TDS0 represents the transparency threshold.

[0010] Preferably, the water after oxidation treatment is fed into a second oxidation tank for further oxidation treatment to obtain pre-purified water.

[0011] Preferably, the pre-purified water is subjected to sedimentation and filtration to obtain purified water and sludge.

[0012] A treatment system for implementing the aforementioned treatment method includes an equalization tank, a flocculation tank, an air flotation tank, an anaerobic tank, an facultative anaerobic tank, and an oxidation tank.

[0013] Preferably, it also includes inclined plate sedimentation tanks, carbon filters and sludge tanks.

[0014] Beneficial effects The advantages of this invention are: 1. Unlike traditional static decomposition methods, this invention uses water circulation in both anaerobic and oxidation processes. This has the advantage of greatly increasing the decomposition speed of organic matter, thereby increasing the wastewater treatment capacity of the system.

[0015] 2. This invention employs a treatment method that combines facultative anaerobic and oxidative processes. Facultative anaerobic treatment can further reduce the organic matter in wastewater that has not been decomposed during anaerobic treatment and requires anaerobic decomposition. At the same time, combined with the oxidative treatment in the first oxidation tank, it can perform preliminary decomposition of the organic matter in wastewater that requires oxidative treatment.

[0016] 3. In the cyclic treatment of facultative anaerobic and oxidative processes, this invention uses water transparency to control the water flow rate. The greater the water transparency, the greater the water circulation flow rate, which allows the bacteria to capture sufficient organic matter, thereby further improving the efficiency of the oxidation treatment. Attached Figure Description

[0017] Figure 1 This is a flowchart of the processing method of the present invention; Figure 2 This is a schematic diagram of the processing system structure of the present invention; Figure 3 This is a schematic diagram of the overall structure of the anaerobic, facultative anaerobic, and oxidation tanks of the present invention. Figure 4 This is a schematic diagram of the water collector structure of the present invention.

[0018] Among them: 1-Grit chamber, 2-Equalization chamber, 3-Flocculation chamber, 4-Air flotation chamber, 5-pH adjustment chamber, 6-Temporary storage chamber, 7-First anaerobic chamber, 8-Second anaerobic chamber, 9-Anoxic chamber, 10-First oxidation chamber, 11-Second oxidation chamber, 12-Reaction chamber, 13-Inclined plate sedimentation chamber, 14-Carbon filter, 15-Sludge chamber, 16-Dynamic flow circulation channel, 17-Constant flow circulation channel, 18-Water storage tank, 19-Water quality transparency sensor, 20-Inlet pipe, 21-T-connector, 22-Water intake pipe, 23-Control valve for water intake pipe, 24-Clear water pipe, 25-Control valve for clear water pipe, 26-Outlet pipe, 27-Control valve for outlet pipe, 28-Exhaust pipe, 29-Level sensor, 30-Grit screen, 171-Upper pumping pipe, 172-Circulation pump, 173-Upper drain pipe, 174-Circulation pipe. Detailed Implementation

[0019] The present invention will be further described below with reference to embodiments, but this does not constitute any limitation on the present invention. Any limited modifications made by any person within the scope of the claims of the present invention are still within the scope of the claims of the present invention. Example 1 See Figure 1 The present invention discloses a method for treating machining wastewater, which mainly consists of two steps: a solid-liquid separation treatment step and an organic matter decomposition treatment step.

[0020] The solid-liquid separation step specifically involves subjecting the machining wastewater to air flotation coagulation to separate the solids and liquids, resulting in pretreated wastewater. Air flotation coagulation is a relatively common wastewater treatment technology. It primarily involves feeding the machining wastewater into an equalization tank to adjust its pH value. After reaching the target pH, the pH-adjusted wastewater is fed into a flocculation tank, where a predetermined amount of flocculant is added based on the water volume. The mixture is stirred thoroughly and reacted for a set reaction time period. During this process, air is introduced into the flocculation tank using a blower to accelerate the reaction. The machined wastewater, after reacting with the flocculant, is then fed into an air flotation tank for a set flotation time period to obtain pretreated wastewater. This pretreated wastewater is rich in organic matter, therefore, it requires subsequent anaerobic and oxidation treatment to decompose this organic matter.

[0021] Specifically, the organic matter decomposition treatment steps of this invention are as follows: pretreated wastewater is treated sequentially using a circulating anaerobic decomposition method and a circulating facultative anaerobic decomposition method to purify the organic matter in the pretreated wastewater, resulting in pre-purified water. Unlike traditional static decomposition methods, this invention employs water circulation in both the anaerobic and oxidation processes. This significantly increases the decomposition speed of organic matter, thereby increasing the wastewater treatment capacity of the system. The two decomposition methods will be described in detail below.

[0022] The circulating anaerobic decomposition method specifically involves setting up two anaerobic tanks, with anaerobic bacteria arranged in the middle of each tank, and a circulating water path connecting the two tanks. Pretreated wastewater is input into these two anaerobic tanks. The water circulation speed and cycle time are set according to the water volume in each tank, controlling the water circulation to create a continuous flow. When the actual water circulation time in each tank reaches the cycle time, the water circulation is stopped, and the anaerobic-treated wastewater is then transported to the next process. By using a circulating flow between the two anaerobic tanks for anaerobic treatment, organic matter in the water can be better captured and decomposed by the anaerobic bacteria through orderly flow. Compared to traditional anaerobic tank techniques that rely solely on gases generated by anaerobic decomposition to influence the flow of organic matter in the water, this invention offers better and more efficient treatment. Specifically, machining wastewater typically requires 4-8 hours to be treated in a traditional anaerobic tank, but with the improved anaerobic treatment method described above, even the largest volume of wastewater can be treated within 3 hours.

[0023] Regarding the setting of water circulation speed and circulation time, considering that the water volume in the anaerobic tank is not the same each time, both the water circulation speed and circulation time need to be set according to the specific water volume. However, in actual operation, the flow velocity of the water in both anaerobic tanks should not exceed 0.2 m / s to ensure that the organic matter in the water can be captured to the maximum extent. For example, when the water in the anaerobic tank is at the lowest treatment level, the water circulation speed can be determined by a flow velocity of 0.2 m / s, and the circulation time can be set to 1-1.5 hours; while when the water in the anaerobic tank is at the highest treatment level, the water circulation speed can be determined by a flow velocity of 0.1 m / s, and the circulation time can be set to 2-3 hours.

[0024] Preferably, after the water circulation in the anaerobic tank stops, the wastewater in both anaerobic tanks is allowed to stand for a predetermined first settling time period before being transported to the next process. The purpose of settling is to allow the precipitates generated during the anaerobic decomposition process to settle, reducing the impact of the precipitates on subsequent oxidation and decomposition.

[0025] The cyclic anaerobic decomposition method specifically involves setting up an anaerobic tank and a first oxidation tank, with the bacterial community positioned in the middle of each tank. A circulating water path is established between the anaerobic tank and the first oxidation tank. This circulating water path is designed to create a recirculation of wastewater between the two tanks. The pretreated wastewater after anaerobic treatment is input into the anaerobic tank and the first oxidation tank, and the water in these tanks is circulated at a set initial flow rate based on the water volume in each tank. The water transparency in the first oxidation tank is monitored at a set monitoring cycle, and the current flow rate is controlled based on the water transparency. When the water transparency reaches a set transparency threshold, the water circulation between the anaerobic tank and the first oxidation tank is stopped, resulting in oxidized water. This invention employs a cyclical treatment method combining anaerobic and oxidative processes. The anaerobic treatment further reduces the amount of organic matter requiring anaerobic decomposition that was not decomposed during the anaerobic treatment in the wastewater. Simultaneously, combined with the oxidation treatment in the first oxidation tank, it enables the preliminary decomposition of organic matter requiring oxidative treatment in the wastewater.

[0026] Unlike anaerobic treatment, the circulating water flow rate in the facultative and oxidative treatment of organic matter is dynamically adjusted. The main reason is that the organic matter content in the wastewater is significantly reduced after facultative and oxidative treatment, resulting in greater transparency. Therefore, as facultative and oxidative processes proceed, the water transparency increases, and the circulating water flow rate should also increase. This allows the bacteria to better capture sufficient organic matter, thereby further improving the efficiency of the oxidation treatment.

[0027] The initial circulation velocity can be obtained through calibration. For example, when both the first oxidation tank and the anoxic tank are at maximum water volume, the circulation velocity of the water in the first oxidation tank and the anoxic tank is set to 0.2 m / s. Based on this circulation velocity, the flow velocity of the water in the circulation path is controlled. When the flow velocity of the water in the circulation path makes the pool water velocity 0.2 m / s, the flow velocity of the water in the circulation path is calibrated as the initial circulation velocity.

[0028] As water transparency increases, the water circulation velocity also increases. Specifically, the current water circulation velocity can be calculated using the following formula: .

[0029] In the formula, V1 is the current circulating velocity of the water body; V0 is the initial circulating velocity; TDS MAX TDS1 represents the transparency value of the pretreated wastewater after anaerobic treatment, which is input into the facultative anaerobic tank and the first oxidation tank; TDS0 represents the water transparency value monitored in the first oxidation tank; and TDS0 represents the transparency threshold.

[0030] As can be seen from the above formula, the greater the water transparency, the greater the water circulation velocity. The specific formula for calculating the current circulation velocity incorporates both a fixed correction factor and a dynamic correction factor based on transparency. and The dynamic correction factor is mainly used to fine-tune the flow rate according to changes in water transparency. The fixed correction factor, on the other hand, ensures that the flow rate increases effectively as water transparency increases.

[0031] Furthermore, in the facultative and oxidative treatment of organic matter, using the relationship between water transparency and its corresponding threshold as the treatment termination condition can better standardize water purification and improve the effectiveness of water treatment compared to a fixed treatment time cycle.

[0032] Preferably, the oxidized water is fed into a second oxidation tank for further oxidation to obtain pre-purified water. The second oxidation tank specifically oxidizes the organic matter in the wastewater, further decomposing the corresponding organic compounds and thus purifying the wastewater.

[0033] The pre-purified water is then subjected to sedimentation and filtration to obtain purified water and sludge, thus completing the treatment process for machining wastewater.

[0034] This invention employs a combination of air flotation coagulation, anaerobic hydrolysis acidification, and oxidation, with a process flow dominated by physicochemical and biochemical processes to treat wastewater. Through separation, sedimentation, conditioning, and biochemical processes, pollutants are separated into solid and liquid components, and organic pollutants are converted into CO2, H2O, and residual sludge, thereby purifying the wastewater and greatly improving the purification efficiency.

[0035] Example 2 See Figure 2 A treatment system for implementing the above-mentioned treatment method includes an equalization tank 2, a flocculation tank 3, an air flotation tank 4, an anaerobic tank, an anoxic tank 9, an oxidation tank, an inclined plate sedimentation tank 13, a carbon filter tank 14, and a sludge tank 15.

[0036] Specifically, after being filtered through the bar screen 1, the machining wastewater is sent to the equalization tank 2 for pH adjustment, and then discharged into the flocculation tank 3. In the flocculation tank 3, flocculants (such as PAM or PAC) are added, causing the fine pollutants in the wastewater to aggregate into larger particles, thus improving the efficiency of the subsequent air flotation process.

[0037] After the wastewater enters the dissolved air flotation (DAF) tank 4, the dissolved air flotation unit in tank 4 releases dissolved air water generated by the dissolved air system through rapid decompression, producing a large number of microbubbles in the water. Several bubbles adhere to the surface of suspended solids or oil in the raw water (or flocculated wastewater), forming suspended solids with an overall density of less than 1. These suspended solids rise to the water surface through buoyancy, thus separating the solids and liquids. This process also reduces BOD, COD, color, etc. After the DAF treatment is completed, the wastewater is fed into the pH adjustment tank 5 for further pH adjustment, and then it can be subjected to anaerobic treatment.

[0038] In this embodiment, a temporary storage tank 6 is provided between the pH adjustment tank 5 and the anaerobic tank to store wastewater.

[0039] Anaerobic tanks utilize the action of anaerobic bacteria to hydrolyze, acidify, and methanate organic matter, removing organic matter from wastewater and improving its biodegradability, which is beneficial for subsequent aerobic treatment. This embodiment has two anaerobic tanks: a first anaerobic tank 7 and a second anaerobic tank 8. The anaerobic bacteria are arranged in the middle of the anaerobic tanks, and a constant-flow-rate circulating water path 17 is set between the two anaerobic tanks. Figure 3 As shown, the specific configuration of this circulating water system involves installing a circulating pump 172 and corresponding pipelines at the top of the two anaerobic tanks. The uppermost water layer of the second anaerobic tank 8 is drawn from the upper pumping pipe 171 to the upper drain pipe 173, from which wastewater is discharged into the uppermost water layer of the first anaerobic tank 7. The two anaerobic tanks are connected below their bacterial communities via a circulating pipe 174. This allows the water in the two anaerobic tanks to circulate after the circulating pumps are started. Furthermore, a sludge accumulation layer is installed at the bottom of the anaerobic tanks, separated from the upper space by a mesh screen 30, to accumulate the sludge produced during the anaerobic reaction.

[0040] The anaerobic wastewater will undergo oxidation treatment. Considering that wastewater treated by a flow-type anaerobic process may retain some untreated organic matter after anaerobic treatment, this embodiment adds an anaerobic treatment, namely an anaerobic tank 9, to the oxidation process, which simultaneously possesses anaerobic and oxidation capabilities. The oxidation treatment in this embodiment employs a contact oxidation tank, where packing material is placed as a carrier for the biofilm. The wastewater to be treated, after oxygenation, flows through the packing material at a certain flow rate, contacting the biofilm. The biofilm and suspended activated sludge work together to purify the wastewater.

[0041] To achieve water flow, this embodiment employs a method of setting up a dynamic flow circulation water path 16 between the anaerobic tank 9 and the first oxidation tank 10. The specific setup method can be referenced from the setup method of the circulation water path in the anaerobic tank described above, and therefore will not be repeated here.

[0042] According to the above processing method, it is necessary to monitor the transparency of the water in the first oxidation tank 10. Since the overall volume of the oxidation tank is large, directly measuring the transparency of the water is not feasible. To address this problem, this embodiment sets up a sampler on the outside of the first oxidation tank 10. Samples are collected from the first oxidation tank 10 using the sampler, and the transparency value of the water in the sampler is measured. Figure 4As shown, the sampler mainly includes a water storage tank 18 equipped with a water transparency sensor 19. The water storage tank 18 is installed on the outer wall of the first oxidation tank 10. An inlet pipe 20 is installed above the water storage tank 18, and a T-connector 21 is installed at the end of the inlet pipe 20. One end of the T-connector 21 is connected to the first oxidation tank 10 through a water intake pipe 22 for water intake, and the other end is connected to an external water source (such as municipal water supply) through a clean water pipe 24. Control valves are installed in both the water intake pipe 22 and the clean water pipe 24. An outlet pipe 26 is installed at the other end of the water storage tank 18. A control valve is also installed in this pipe. The end of the outlet pipe 26 is connected to the first oxidation tank 10, allowing the wastewater after testing or the water used to clean the sampler to flow back into the first oxidation tank 10.

[0043] After opening the control valve 23 of the water intake pipe, water in the first oxidation tank 10 will automatically flow into the storage tank 18. Once the storage tank 18 is full, the control valve is closed, and the water transparency signal is acquired by the water transparency sensor 19 and transmitted to the controller. This signal is used to control the output power of the circulating pump, thereby regulating the flow rate of the circulating water in the anoxic tank 9 and the first oxidation tank 10. After the water transparency signal is acquired, the control valve 27 of the outlet pipe is opened to empty the water in the storage tank 18. Next, the control valve 25 of the clean water pipe is opened to introduce clean water to clean the storage tank 18. After cleaning, the control valves 25 of the clean water pipe and 27 of the outlet pipe are closed sequentially.

[0044] The connection point between the water intake pipe 22 and the first oxidation tank 10 is located above the connection point between the water outlet pipe 26 and the first oxidation tank 10. This means that water can be drawn simply by opening the control valve 23 of the water intake pipe, eliminating the need for pumping, which is very convenient.

[0045] To achieve automatic water intake, an exhaust pipe 28 is installed above the water storage tank 18 in this embodiment. A liquid level sensor 29 is installed in the exhaust pipe 28. The liquid level sensor 29 and the control valve 23 of the water intake pipe are electrically connected to the controller. During water intake, gas in the water storage tank 18 is discharged through the exhaust pipe 28. When the water storage tank 18 is full, water will enter the exhaust pipe 28. When the water in the exhaust pipe 28 reaches the liquid level sensor 29, the liquid level sensor 29 sends a signal to the controller. The controller then controls the control valve 23 of the water intake pipe to close based on the signal, thereby stopping water intake. The liquid level sensor 29 must be installed above the connection between the water intake pipe 23 and the first oxidation tank 10. In addition, a perforated sealing plug can be installed above the exhaust pipe 28 to prevent foreign objects from entering the exhaust pipe 28.

[0046] To improve the purification of organic matter in the water, a second oxidation tank 11 is provided in this embodiment. The second oxidation tank 11 also contains packing material, which serves as a carrier for the biofilm. The difference is that wastewater from the first oxidation tank 10 is discharged into the lower part of the second oxidation tank 11, and after passing through the packing layer, overflows from the top of the second oxidation tank without needing to be allowed to settle.

[0047] Because the anaerobic and oxidation processes produce acidic substances, the wastewater discharged from the second oxidation tank 11 needs to be treated again in a reaction tank 12 to adjust the water quality before being transported to the inclined plate sedimentation tank 13. The inclined plates in the inclined plate sedimentation tank 13 are made of 45-degree honeycomb-shaped inclined tubes. The principle is that when wastewater flows upwards by gravity, it is deflected at a 45-degree angle as it passes through the inclined plate packing. Pollutants adhere to the inclined plate packing and fall off, while the clean water flows upwards by gravity, resulting in high pollutant removal efficiency. The main purpose of setting up the inclined plate sedimentation tank 13 here is to settle pollutants in the water overflowing from the second oxidation tank 11 and prevent clogging of the sand and carbon filter tank 14.

[0048] After sedimentation, the water is fed into the carbon filter 14. The carbon filter 14 can trap suspended solids in the water, remove iron, manganese, colloids, and silt, and reduce the turbidity of the water. It utilizes the well-developed fine pore structure and huge specific surface area of ​​activated carbon to adsorb the remaining metal ions in the water, and has a good removal effect on color and odor.

[0049] Sludge tank 15 is used to collect the sludge generated in the above-mentioned tanks, so as to facilitate centralized transportation and treatment.

[0050] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention, and these will not affect the effectiveness of the implementation of the present invention or the practicality of the patent.

Claims

1. A method for treating machining wastewater, characterized in that, The method involves subjecting the machining wastewater to air flotation coagulation treatment to achieve solid-liquid separation and obtain pretreated wastewater. The pretreated wastewater is treated sequentially by cyclic anaerobic decomposition and cyclic facultative anaerobic decomposition to purify the organic matter in the pretreated wastewater and obtain pre-purified water. Specifically, the cyclic anaerobic decomposition method involves: setting up two anaerobic tanks and arranging anaerobic bacteria in the middle of each tank; establishing a circulating water path between the two tanks; inputting the pretreated wastewater into the two anaerobic tanks; setting the water circulation speed and circulation time period based on the water volume of each tank; controlling the water circulation in the two tanks according to the water circulation speed to create a circulating flow; stopping the water circulation in the anaerobic tanks when the actual water circulation time in each tank reaches the circulation time period; and then transporting the anaerobic pretreated wastewater to the next process. The cyclic anaerobic decomposition method specifically involves: setting up an anaerobic tank and a first oxidation tank, with the bacterial community arranged in the middle of the tanks; establishing a circulating water path between the anaerobic tank and the first oxidation tank; inputting the pretreated wastewater after anaerobic treatment into the anaerobic tank and the first oxidation tank, and controlling the water in the tanks to circulate at a set initial circulation rate based on the water volume in these two tanks; monitoring the water transparency in the first oxidation tank, and controlling the current circulation rate of the water body based on the water transparency; stopping the water circulation between the anaerobic tank and the first oxidation tank when the water transparency reaches a set transparency threshold, to obtain the oxidized water body; The current circulating velocity of the water body can be calculated using the following formula: ， In the formula, V1 is the current circulating velocity of the water body; V0 is the initial circulating velocity; TDS MAX TDS1 represents the transparency value of the pretreated wastewater after anaerobic treatment, which is input into the facultative anaerobic tank and the first oxidation tank; TDS0 represents the water transparency value monitored in the first oxidation tank; and TDS0 represents the transparency threshold.

2. The method for treating machining wastewater according to claim 1, characterized in that, The air flotation coagulation treatment method is as follows: the machining wastewater is input into an equalization tank for pH adjustment. After the pH of the machining wastewater is adjusted to the set target pH value, the pH-adjusted machining wastewater is input into a flocculation tank. A set amount of flocculant is added according to the water volume in the flocculation tank. After stirring evenly and reacting for a set reaction time period, the machining wastewater reacting with the flocculant is input into an air flotation tank for air flotation treatment for a set air flotation time period to obtain the pretreated wastewater.

3. The method for treating machining wastewater according to claim 1, characterized in that, After the water circulation in the anaerobic tank stops, the wastewater in both anaerobic tanks is allowed to stand for a set first set time period before the pretreated wastewater after anaerobic treatment is transported to the next process.

4. The method for treating machining wastewater according to claim 1, characterized in that, The water after oxidation treatment is fed into a second oxidation tank for further oxidation treatment to obtain pre-purified water.

5. The method for treating machining wastewater according to claim 1, characterized in that, The pre-purified water is then subjected to sedimentation and filtration to obtain purified water and sludge.

6. A processing system for implementing the processing method according to any one of claims 1-5, characterized in that, It includes equalization tanks, flocculation tanks, dissolved air flotation tanks, anaerobic tanks, facultative anaerobic tanks, and oxidation tanks.

7. The machining wastewater treatment system according to claim 6, characterized in that, It also includes inclined plate sedimentation tanks, carbon filters, and sludge tanks.

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