Chip grinding wastewater concentrated solution deep treatment process and system

Abstract

The invention discloses an advanced treatment process for a chip grinding wastewater concentrated solution. The advanced treatment process comprises the following steps: introducing the concentrated solution into a pH adjusting unit, presetting multiple groups of pH target values through a PLC (Programmable Logic Controller), monitoring in real time through an online pH instrument, automatically adjusting the dosage according to gradient switching logic, and recording data; the concentrated solution subjected to pH regulation sequentially enters a PAC dosing unit and a PAM dosing unit, and a dosing pump and a pneumatic diaphragm valve are controlled by a PLC to quantitatively add chemicals to form a flocculating constituent; mixed liquid containing flocculates enters a high-pressure diaphragm filter press, and a PLC controls a screw pump and a pneumatic diaphragm pump to perform linkage feeding; and the pressure filtrate is discharged into a collecting box and is conveyed to a wastewater collecting box by a PLC (Programmable Logic Controller) according to a liquid level signal control conveying pump. The whole process is automatically controlled through a PLC (Programmable Logic Controller), and the filter-pressing saturation time and the water content of a filter cake are effectively and accurately controlled through linkage control such as multi-section pH regulation control, dosing linkage and pumping linkage, so that the actual filter-pressing saturation time is lower than that in the prior art, and the water content of the filter cake is lower than that in the prior art.

Description

Technical Field

[0001] This invention belongs to the field of industrial wastewater treatment technology, specifically relating to a deep treatment process and system for concentrated grinding wastewater generated during chip manufacturing, and is particularly suitable for the efficient treatment and purification of concentrated wastewater generated during the recycling of cleaning wastewater from grinding, dicing, and cutting processes in chip packaging. Background Technology

[0002] In chip packaging processes, steps such as grinding, dicing, and cutting generate a large amount of cleaning wastewater. In response to the call for energy conservation and emission reduction, this wastewater is usually collected and reused. However, the wastewater reuse process produces a high-concentration concentrate, which requires complex treatment to meet discharge standards or undergo further disposal.

[0003] In existing treatment processes, the concentrate must first enter a reaction sedimentation tank for chemical dosing, and then the resulting precipitate is subjected to filter press treatment. This process has significant drawbacks: firstly, the reaction sedimentation tank and filter press equipment are set up separately, requiring a large area, which is particularly unsuitable for chip manufacturing workshops with limited space; secondly, the process is cumbersome, requiring manual intervention or segmented control in stages such as chemical dosing, sedimentation, and filter press, resulting in low automation and low treatment efficiency. Furthermore, the insufficient sludge concentration during the precipitate filter press process leads to a slow saturation rate of the filter press, further restricting the overall treatment efficiency.

[0004] Therefore, developing a deep treatment process and system for chip grinding wastewater concentrate that is small in footprint, has a simplified process, a high degree of automation, and can improve the efficiency of pressure filtration has become an urgent technical problem to be solved in this field. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing chip grinding wastewater concentrate treatment processes, such as large footprint, cumbersome process, and low efficiency, and to provide a deep treatment process and system for chip grinding wastewater concentrate, which achieves efficient treatment of concentrate through full-process automated control and process optimization.

[0006] A process and system for deep treatment of concentrated chip grinding wastewater, characterized by comprising the following steps: 1) Introduce the chip grinding wastewater concentrate into the pH adjustment unit and realize the automatic adjustment of pH value through PLC control: preset multiple pH target values, use an online pH meter to monitor the pH value of the concentrate in real time, and the PLC program automatically adjusts the dosage according to the difference between the monitored value and the current target value according to the preset gradient switching logic, while recording relevant data throughout the adjustment process; 2) After pH adjustment, the concentrated solution enters the PAC dosing unit. The PLC controls the operating parameters of the dosing pump and the on / off state of the pneumatic diaphragm valve to quantitatively add PAC to the concentrated solution. 3) After PAC is added, the mixture enters the PAM dosing unit, where the PLC controls the dosing pump to quantitatively add PAM to the mixture, causing the particulate matter in the mixture to form flocs; 4) The mixed liquor containing flocculants enters the high-pressure diaphragm filter press for filtration. The PLC controls the screw pump and the pneumatic diaphragm pump to operate in conjunction: first, the filter chamber of the filter press is filled by the screw pump, and then the pneumatic diaphragm pump is switched to feed the sludge. The pneumatic diaphragm pump is used to fill the remaining gaps in the filter chamber by utilizing its pressure-holding characteristic, thus completing the filtration. 5) The filtrate produced by the filter press is discharged into the filtrate collection tank, and the filtrate is transported to the wastewater collection tank by the filtrate delivery pump. The start and stop of the filtrate delivery pump is automatically controlled by the PLC control module according to the liquid level signal of the filtrate collection tank. The entire process described above is automated through electrical programming, with PLC controlling the parameters of each step.

[0007] Preferably, in step (1), the preset multiple pH target values ​​are 3-6 groups, and the difference between two adjacent target values ​​is 0.5-2.0 pH units; the gradient switching logic is as follows: when the pH value monitored by the online pH meter deviates from the current preset target value by less than or equal to ±0.2 pH units, the PLC program automatically switches to the next set of pH target values ​​and adjusts the dosage accordingly; the online pH meter monitors every 1-5 seconds to ensure timely capture of pH changes; the recorded data includes, but is not limited to, pH adjustment time, real-time pH value, dosage at each gradient switch, number of gradient switches, and corresponding time points, and all data are stored in the storage unit of the PLC control module. By adjusting the pH value in segments, water quality fluctuations caused by one-time dosing are avoided, adapting to large-flow wastewater treatment scenarios, providing a stable acid-base environment for subsequent flocculation reactions, and enhancing the agglomeration of particles such as silica powder.

[0008] Preferably, in step (2), the dosing pump is a metering pump with a flow rate adjustment accuracy of ±1%, which can accurately control the dosage of PAC. The pneumatic diaphragm valve forms a linkage and interlock mechanism with the dosing pump. When the dosing pump stops running, the pneumatic diaphragm valve automatically closes to prevent reagent leakage or backflow. The PLC dynamically adjusts the stroke and frequency of the metering pump in real time according to the signal fed back by the wastewater flow sensor at the outlet of the pH adjustment unit, so that the dosage of PAC matches the wastewater flow rate, ensuring that the concentration of PAC in the wastewater is stable within the preset range of 0.1-0.5 g / L. At the same time, a pressure sensor is installed in the pipeline of the PAC dosing unit. When the pipeline pressure exceeds 0.3 MPa, the PLC control module issues an alarm signal and automatically stops the dosing pump. As an inorganic flocculant, PAC destabilizes fine particles through adsorption and charge neutralization. The metering dosing and pressure protection design ensures the stability of the flocculation effect and avoids reagent waste or pipeline failure.

[0009] Preferably, in step (3), the dosing pump is a variable dosing pump. The PLC adjusts the dosage of PAM according to the data monitored by the turbidity sensor of the mixed liquid at the outlet of the PAC dosing unit, according to a preset ratio. When the turbidity of the mixed liquid is 100-300 NTU, the mass ratio of PAM dosage to PAC dosage is 1:0.2-1:0.3. When the turbidity is >300 NTU, the ratio is adjusted to 1:0.3-1:0.5. When the turbidity is <100 NTU, the ratio is adjusted to 1:0.1-1:0.2, so as to ensure that the formed flocs are uniform in size and compact in structure, with a particle size range of 0.5-2 mm, thereby improving the efficiency of subsequent pressure filtration. The mass ratio of PAM dosage to PAC dosage is 1:0.1-1:0.5, and the operating status and dosage of the dosing pump are recorded by the PLC in real time. As a polymeric flocculant, PAM aggregates pretreated PAC particles into large-diameter flocs through bridging. The dosage is also linked to turbidity, ensuring flocculation effect while reducing reagent consumption.

[0010] Preferably, in step (4), the flow rate of the screw pump is 10-50 m³ / h. During the feeding process into the filter chamber of the filter press, the PLC monitors the feeding situation in real time through the flow sensor and pressure sensor installed at the feed inlet of the filter press. When the filter chamber is detected to be filled to 75%-85% of its capacity, the PLC sends a signal to stop the operation of the screw pump. Then, the pneumatic diaphragm pump is started. The working pressure range of the pneumatic diaphragm pump is 0.6-1.2 MPa. Using its pressure-holding function, the remaining gaps in the filter chamber are completely filled. During the filtration process, the PLC monitors the filter chamber pressure and liquid output parameters of the filter press in real time. When the liquid output is less than 0.5 m³ / h for 5 consecutive minutes, it is determined that the preset filtration endpoint condition has been reached, and the filtration process is automatically stopped. The combination of dual pump linkage and pressure-holding characteristics improves the filter chamber filling rate and sludge concentration, shortens the sludge feeding time by 30%-40%, and improves the filtration efficiency.

[0011] Preferably, in step (5), the filtrate collection tank is equipped with a liquid level sensor. When the liquid level reaches 60%-80% of the collection tank's volume, the liquid level sensor sends a signal to the PLC control module, and the PLC controls the filtrate delivery pump to start automatically. When the liquid level is below 20% of the collection tank's volume, the PLC controls the filtrate delivery pump to stop automatically. The filtrate collection tank is also equipped with a stirring device, which is controlled by the PLC to start intermittently. The stirring frequency is once per hour, and each stirring lasts for 5 minutes to prevent sedimentation in the collection tank. Liquid level linkage control realizes automated filtrate transfer, and intermittent stirring avoids the deposition of fine particles, ensuring the stability of subsequent processing.

[0012] A chip grinding wastewater concentrate deep treatment system for implementing any of the processes described above, comprising: 1) pH adjustment unit: It consists of a pH adjustment tank, an online pH meter, two sets of pH adjustment agent storage tanks, corresponding dosing pumps and pipelines. The online pH meter is installed in the pH adjustment tank to monitor the pH value of the concentrate in the tank in real time. Its signal output terminal is electrically connected to the PLC control module. The control terminal of the dosing pump is electrically connected to the PLC control module. The PLC control module controls the operation of the dosing pump according to the monitoring data of the online pH meter to realize the quantitative addition of pH adjustment agent. 2) PAC dosing unit: includes a PAC storage tank, a metering pump, a pneumatic diaphragm valve, and connecting pipelines. The inlet of the metering pump is connected to the PAC storage tank through a pipeline, and the outlet is connected to the outlet pipeline of the pH adjustment unit through a pipeline connected to the pneumatic diaphragm valve. The control terminals of the metering pump and the pneumatic diaphragm valve are electrically connected to the PLC control module, which controls the quantitative dosing of PAC and the opening and closing of the pipeline. 3) PAM dosing unit: It consists of a PAM storage tank, a variable dosing pump and connecting pipelines. The inlet of the variable dosing pump is connected to the PAM storage tank, and the outlet is connected to the outlet pipeline of the PAC dosing unit through the pipeline. The control terminal of the variable dosing pump is electrically connected to the PLC control module. The PLC control module controls the dosing of PAM according to relevant monitoring data. 4) High-pressure diaphragm filter press unit: This unit includes a high-pressure diaphragm filter press, a screw pump, a pneumatic diaphragm pump, a pressure sensor, a flow sensor, and connecting pipelines. The inlets of the screw pump and the pneumatic diaphragm pump are connected to the outlet pipeline of the PAM dosing unit via pipelines, and their outlets are connected to the feed inlet of the high-pressure diaphragm filter press. The pressure sensor and the flow sensor are installed on the feed pipeline of the filter press, and their signal output terminals are electrically connected to the PLC control module. The control terminals of the screw pump and the pneumatic diaphragm pump are electrically connected to the PLC control module. The PLC control module controls the coordinated operation of the screw pump and the pneumatic diaphragm pump based on the monitoring data from the sensors. 5) Filtrate treatment unit: includes a filtrate collection tank, a filtrate transfer pump, and a wastewater collection tank. The inlet of the filtrate collection tank is connected to the filtrate outlet of the high-pressure diaphragm filter press via a pipeline. The outlet of the filtrate collection tank is connected to the inlet of the filtrate transfer pump via a pipeline. The outlet of the filtrate transfer pump is connected to the wastewater collection tank via a pipeline. A liquid level sensor is installed inside the filtrate collection tank. The liquid level sensor and the filtrate transfer pump are both electrically connected to the PLC control module. 6) PLC Control Module: The human-machine interface and data storage unit are electrically connected to the electrical equipment in the pH adjustment unit, PAC dosing unit, PAM dosing unit, high-pressure diaphragm filter press unit, and filtrate treatment unit, respectively. It receives monitoring data from each sensor, controls the operating parameters of each device according to a preset program, and records relevant data throughout the entire processing. The human-machine interface can display the real-time operating status, monitoring parameters, and historical data curves of each unit. Operators can use this interface to set relevant parameters and modify the control program. The data storage unit stores all monitoring data and operation records during system operation for at least six months to facilitate subsequent process analysis and troubleshooting.

[0013] Preferably, the pH adjustment tank in the pH adjustment unit is also equipped with a stirring device. The control terminal of the stirring device is electrically connected to the PLC control module. The PLC control module controls the start, stop and stirring speed of the stirring device according to the liquid volume in the pH adjustment tank or the pH adjustment process. The stirring speed can be adjusted within the range of 100-300 r / min. When the pH value gradient changes, the stirring speed automatically increases to 200-300 r / min to accelerate the mixing of the reagent and the concentrate. When the pH value is stable, the stirring speed decreases to 100-200 r / min to save energy.

[0014] Preferably, both the PAC dosing unit and the PAM dosing unit are equipped with a level sensor and a concentration sensor on their storage tanks. The level sensor monitors the liquid level of the reagent, and when the liquid level in the storage tank is lower than the preset minimum level, the PLC control module issues an alarm signal to remind the operator to replenish the reagent in time. The concentration sensor monitors the concentration of the reagent, and when the concentration is lower than the preset value, the PLC control module also issues an alarm signal. At the same time, the storage tank is also equipped with a stirring device, which is automatically started by the PLC at a frequency of 10 minutes every 30 minutes to prevent the reagent from settling.

[0015] Preferably, the high-pressure diaphragm filter press unit also includes a filter cake thickness sensor. This sensor is installed on the filter plate of the high-pressure diaphragm filter press to monitor the thickness of the filter cake. Its signal output terminal is electrically connected to the PLC control module. When the filter cake thickness reaches a preset value, the PLC control module determines that the filter press is saturated, automatically controls the stopping of mud feeding, and enters the pressing stage. After pressing is completed, the PLC control module controls the opening of the filter press, cake unloading, and other actions according to a preset program to achieve automated operation.

[0016] In summary, the present invention has the following beneficial effects: Automation and intelligence: The entire process is controlled by PLC to achieve pH gradient adjustment, dynamic control of chemical dosage, and linkage of dual pumps in the filter press, reducing manual intervention and solving the cumbersome problems of traditional processes.

[0017] Process optimization: segmented pH adjustment improves water quality stability, dual-pump linkage filtration enhances efficiency, automated filtrate treatment reduces sedimentation, and overall footprint is reduced.

[0018] Energy-saving and efficient: The dosing of chemicals is linked to water quality parameters, reducing chemical consumption; the improved filter press efficiency shortens the treatment cycle and reduces energy consumption; This invention achieves effective and precise control of filtration saturation time and filter cake moisture content through coordinated control mechanisms, such as multi-stage pH adjustment, chemical dosing coordination, and pumping coordination. This results in a lower actual filtration saturation time and lower filter cake moisture content compared to existing technologies. The coordinated control mechanism of this invention enables precise control, thereby achieving both efficiency and cost savings. Detailed Implementation

[0019] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

[0020] Example 1

[0021] The concentrated wastewater from chip grinding has a silicon powder concentration of 6000±500 mg / L, an initial pH of 7.0±0.3, a turbidity of 200±30 NTU, and a treatment flow rate of 20 m³ / h. The treatment utilizes the process and system of this invention, and the specific operation is as follows: pH adjustment: The PLC presets target pH values ​​of 5.5, 4.5, and 3.5, and the online pH meter monitors the pH every 2 seconds. When the concentrate enters the pH adjustment tank, the initial pH is 7.0. The PLC controls the acidic regulator dosing pump to start. When the pH drops to 5.5±0.2, it automatically switches to the next target value. Finally, it stabilizes at 3.5±0.2. The entire adjustment process takes 15 minutes, with a cumulative dosage of 8.2 kg. Recorded data includes pH value, dosage, and number of switching times at each time point.

[0022] PAC dosing: The pH-adjusted concentrate enters the PAC dosing unit. Based on the 20 m³ / h signal from the flow sensor, the PLC controls the metering pump to add PAC at a concentration of 0.3 g / L, corresponding to a pump stroke frequency of 40 Hz. The pneumatic diaphragm valve is linked to the dosing pump; the valve opens when the pump starts and closes when the pump stops. The pipeline pressure is stable at 0.22 MPa, and no alarm is triggered.

[0023] PAM dosing: The turbidity of the PAC mixture outlet was monitored to be 210 NTU. The PLC controlled the variable dosing pump according to the PAM to PAC dosing mass ratio of 1:0.25, corresponding to a flow rate of 12 L / h, forming flocs with a particle size of 1.2 ± 0.2 mm.

[0024] High-pressure diaphragm filtration: The mixed liquor containing flocculants enters the filter press. The PLC first starts the screw pump at a flow rate of 30 m³ / h, which is monitored by the inlet flow and pressure sensors. When the filter chamber is filled to 80% and the pressure is 0.4 MPa, the screw pump stops. Then, the pneumatic diaphragm pump is switched to a working pressure of 1.0 MPa, and the filter chamber is filled after 1.2 hours of continuous feeding. During the filtration process, the liquid output gradually decreases. When the liquid output is <0.5 m³ / h for 5 consecutive minutes, the PLC determines the end of the filtration process and automatically stops the machine. The total sludge feeding time is 3 hours. The filter press is saturated, the sludge cake thickness reaches 18-20 mm, the moisture content is 55%, and the turbidity of the filtrate is ≤50 NTU.

[0025] Filtrate treatment: The filtrate is discharged into the wastewater collection tank. When the liquid level sensor detects that the liquid level in the filtrate collection tank reaches 70%, the filtrate transfer pump starts automatically. When the liquid level drops to 20%, the transfer pump stops. The stirring device in the filtrate collection tank starts once an hour according to the preset program, stirring for 5 minutes each time at a speed of 150 r / min.

[0026] Example 2

[0027] The concentrated wastewater from chip grinding has a silicon powder concentration of 9000±500 mg / L, an initial pH of 7.2±0.3, a turbidity of 350±30 NTU, and a treatment flow rate of 18 m³ / h. The treatment utilizes the process and system of this invention, and the specific operation is as follows: pH adjustment: The PLC presets target pH values ​​of 6.0, 5.0, 4.0, and 3.0, and the online pH meter monitors the pH at a frequency of 1 second per cycle. When the concentrate enters the pH adjustment tank, the initial pH is 7.2. The PLC controls the acidic regulator dosing pump to start. When the pH drops to 6.0±0.2, it automatically switches to the next target value. Finally, it stabilizes at 3.0±0.2. The entire adjustment process takes 18 minutes, with a cumulative dosage of 11.5 kg. Recorded data includes pH value, dosage, and number of switching times at each time point.

[0028] PAC dosing: The pH-adjusted concentrate enters the PAC dosing unit. Based on the 18 m³ / h signal from the flow sensor, the PLC controls the metering pump to add PAC at a concentration of 0.4 g / L, corresponding to a pump stroke frequency of 45 Hz. The pneumatic diaphragm valve is linked to the dosing pump; the valve opens when the pump starts and closes when the pump stops. The pipeline pressure is stable at 0.25 MPa, and no alarm is triggered.

[0029] PAM dosing: The turbidity of the PAC mixture outlet was monitored at 340 NTU. The PLC controlled the variable dosing pump according to the PAM to PAC dosing mass ratio of 1:0.35, corresponding to a flow rate of 15 L / h, forming flocs with a particle size of 1.8 ± 0.2 mm.

[0030] High-pressure diaphragm filtration: The mixed liquor containing flocculants enters the filter press. The PLC first starts the screw pump at a flow rate of 28 m³ / h, which is monitored by the inlet flow and pressure sensors. When the filter chamber is filled to 82% and the pressure is 0.45 MPa, the screw pump stops. Then, the pneumatic diaphragm pump is switched to a working pressure of 1.1 MPa. After feeding for 1 hour, the filter chamber is filled. During the filtration process, the liquid output gradually decreases. When the liquid output is <0.5 m³ / h for 5 consecutive minutes, the PLC determines the end of the filtration process and automatically stops the machine. The total sludge feeding time is 2.8 hours. The filter press is saturated, the cake thickness reaches 25-28 mm, the moisture content is 56%, and the turbidity of the filtrate is ≤45 NTU.

[0031] Filtrate treatment: The filtrate is discharged into the wastewater collection tank. When the liquid level sensor detects that the liquid level in the filtrate collection tank reaches 75%, the filtrate transfer pump will start automatically. When the liquid level drops to 18%, the transfer pump will stop. The stirring device in the filtrate collection tank will start once an hour according to the preset program, stirring for 5 minutes each time at a speed of 150 r / min.

[0032] Example 3

[0033] The concentrated wastewater from chip grinding has a silicon powder concentration of 5000±300 mg / L, an initial pH of 6.8±0.3, a turbidity of 150±20 NTU, and a treatment flow rate of 10 m³ / h. The treatment utilizes the process and system of this invention, and the specific operation is as follows: pH adjustment: The PLC presets the target pH values ​​to 5.0 and 4.0, and the online pH meter monitors the pH every 3 seconds. When the concentrate enters the pH adjustment tank, the initial pH is 6.8. The PLC controls the acidic regulator dosing pump to start. When the pH drops to 5.0±0.2, it automatically switches to the next target value. Finally, it stabilizes at 4.0±0.2. The entire adjustment process takes 10 minutes, with a total dosage of 4.5 kg. Recorded data includes pH value, dosage, and number of switching times at each time point.

[0034] PAC dosing: The pH-adjusted concentrate enters the PAC dosing unit. Based on the 10 m³ / h signal from the flow sensor, the PLC controls the metering pump to add PAC at a concentration of 0.2 g / L, corresponding to a pump stroke frequency of 25 Hz. The pneumatic diaphragm valve is linked to the dosing pump; the valve opens when the pump starts and closes when the pump stops. The pipeline pressure is stable at 0.18 MPa, and no alarm is triggered.

[0035] PAM dosing: The turbidity of the PAC mixture outlet was monitored to be 140 NTU. The PLC controlled the variable dosing pump according to the PAM to PAC dosing mass ratio of 1:0.15, corresponding to a flow rate of 8 L / h, forming flocs with a particle size of 0.8±0.1 mm.

[0036] High-pressure diaphragm filtration: The mixed liquor containing flocculants enters the filter press. The PLC first starts the screw pump at a flow rate of 15 m³ / h, which is monitored by the inlet flow and pressure sensors. When the filter chamber is filled to 78% and the pressure is 0.35 MPa, the screw pump stops. Then, the pneumatic diaphragm pump is switched to a working pressure of 0.9 MPa, and the filter chamber is filled after 0.8 hours of continuous feeding. During the filtration process, the liquid output gradually decreases. When the liquid output is <0.5 m³ / h for 5 consecutive minutes, the PLC determines the end of the filtration process and automatically stops the machine. The total sludge feeding time is 2.2 hours. The filter press is saturated, the sludge cake thickness reaches 15-17 mm, the moisture content is 58%, and the turbidity of the filtrate is ≤55 NTU.

[0037] Filtrate treatment: The filtrate is discharged into the wastewater collection tank. When the liquid level sensor detects that the liquid level in the filtrate collection tank reaches 65%, the filtrate transfer pump will start automatically. When the liquid level drops to 20%, the transfer pump will stop. The stirring device in the filtrate collection tank will start once every 2 hours according to the preset program, stirring for 5 minutes each time at a speed of 150 r / min.

[0038] Comparative Example 1 The concentrated wastewater from chip grinding has a silicon powder concentration of 9000±500 mg / L, an initial pH of 7.2±0.3, a turbidity of 350±30 NTU, and a treatment flow rate of 18 m³ / h. This treatment method is not used; the specific operation is as follows: Pretreatment: Only the concentrate is introduced into the pH adjustment tank without adding pH adjuster, maintaining the initial pH at 7.2±0.3. The tank is stirred continuously at 150r / min for 30 minutes and then allowed to stand.

[0039] Without PAC / PAM dosing, relying on natural sedimentation, the turbidity of the supernatant was 300±20 NTU after standing for 2 hours, indicating that the silica powder particles did not effectively agglomerate.

[0040] Filter press sludge feeding: A single pneumatic diaphragm pump is used for sludge feeding, with a pump operating pressure of 1.1 MPa. Only a pressure sensor is installed at the feed inlet, without a flow sensor linkage. After starting the pneumatic diaphragm pump, due to the lack of silica flocculent formation and high particle dispersion, the filter cloth has high water permeability resistance, resulting in a slow sludge feeding rate. In the first two hours, the filter chamber filling rate is only 20%, and the pressure rises to 0.3 MPa. Feeding continues until the 8th hour, when the filter chamber pressure reaches 1.1 MPa. Monitoring by the filter cake thickness sensor shows a filter chamber filling rate of only 90% (due to dispersed particles clogging the filter cloth pores, it cannot be completely filled), indicating that the filter press is saturated. During the filtration process, the liquid output remains below 0.3 m³ / h. Sludge feeding stops in the 8th hour, and the pressing stage begins. The final cake thickness is 8-10 mm, with a moisture content of 75% ± 2%, and the filtrate turbidity is 150 ± 10 NTU.

[0041] Filtrate treatment: The filtrate is discharged into the wastewater collection tank. When the liquid level sensor detects that the liquid level in the filtrate collection tank reaches 75%, the filtrate transfer pump will start automatically. When the liquid level drops to 18%, the transfer pump will stop. The stirring device in the filtrate collection tank will start once an hour according to the preset program, stirring for 5 minutes each time at a speed of 150 r / min.

[0042] Comparative Example 2 The concentrated wastewater from chip grinding has a silicon powder concentration of 9000±500 mg / L, an initial pH of 7.2±0.3, a turbidity of 350±30 NTU, and a treatment flow rate of 18 m³ / h. This treatment method is not used; the specific operation is as follows: Pretreatment: Only the concentrate is introduced into the pH adjustment tank without adding pH adjuster, maintaining the initial pH at 7.2±0.3. The tank is stirred continuously at 150r / min for 30 minutes and then allowed to stand.

[0043] Without PAC / PAM dosing, relying on natural sedimentation, the turbidity of the supernatant after standing for 2 hours was 300±20 NTU, indicating that the silica powder particles were dispersed.

[0044] Filter press sludge feeding: A single screw pump is used for sludge feeding, with a pump flow rate of 28 m³ / h. A flow sensor is installed at the feed inlet, but no pressure sensor is present. After starting the screw pump, due to the lack of flocculation of particles, although the feed flow rate is high, the filter cloth's retention efficiency is low. Within the first hour, the filter chamber is filled to 40%. Due to the high thrust of the screw pump, the dispersed particles are forcibly pressed into the filter chamber. Feeding continues until the 5th hour, when the filter chamber pressure suddenly rises to 0.6 MPa. The dispersed particles form a dense filter layer on the filter cloth surface, resulting in a sharp increase in resistance. The screw pump overload alarm is triggered. At this point, the filter cake thickness is 10-12 mm. Because the particles cannot effectively agglomerate, the filter chamber space is occupied by low-concentration sludge, indicating that the filter press is saturated. The filter cake thickness is 10-12 mm, the moisture content is 72% ± 2%, and the turbidity of the filtrate is 130 ± 10 NTU.

[0045] Filtrate treatment: The filtrate is discharged into the wastewater collection tank. When the liquid level sensor detects that the liquid level in the filtrate collection tank reaches 75%, the filtrate transfer pump will start automatically. When the liquid level drops to 18%, the transfer pump will stop. The stirring device in the filtrate collection tank will start once an hour according to the preset program, stirring for 5 minutes each time at a speed of 150 r / min.

[0046] Key data comparison conclusions: The filter press saturation time of Comparative Example 1 was 8 hours, which was 5.2 hours longer than the 2.8 hours of Example 2, and the efficiency decreased by 65%; the cake thickness was 8-10 mm, which was only about 35% of that of Example 2; in terms of treatment effect, the cake moisture content was high and the turbidity of the filter press exceeded the standard.

[0047] The filter press saturation time of Comparative Example 2 was 5 hours, which was 2.2 hours longer than the 2.8 hours of Example 2, and the efficiency decreased by 44%; the filter cake thickness was 10-12 mm, which was only about 43% of that of Example 2; in terms of treatment effect, the filter cake was easy to break, had high water content, and the turbidity of the filter liquid exceeded the standard.

[0048] Example 2, using a "PAC / PAM flocculation + screw pump + pneumatic diaphragm pump linkage" process, showed significant advantages over Comparative Example 1 ("single pneumatic diaphragm pump + no reagent") and Comparative Example 2 ("single screw pump + no reagent") in terms of filter press saturation time, cake thickness, and treatment effect, thus verifying the efficiency and necessity of the process of the present invention.

Claims

1. A deep treatment process for concentrated chip grinding wastewater, characterized in that, Includes the following steps: 1) Introduce the chip grinding wastewater concentrate into the pH adjustment unit and realize the automatic adjustment of pH value through PLC control: preset multiple pH target values, use an online pH meter to monitor the pH value of the concentrate in real time, and the PLC program automatically adjusts the dosage according to the difference between the monitored value and the current target value according to the preset gradient switching logic, while recording relevant data throughout the adjustment process; 2) After pH adjustment, the concentrated solution enters the PAC dosing unit. The PLC controls the operating parameters of the dosing pump and the on / off state of the pneumatic diaphragm valve to quantitatively add PAC to the concentrated solution. 3) After PAC is added, the mixture enters the PAM dosing unit, where the PLC controls the dosing pump to quantitatively add PAM to the mixture, causing the particulate matter in the mixture to form flocs; 4) The mixed liquor containing flocculants enters the high-pressure diaphragm filter press for filtration. The PLC controls the screw pump and the pneumatic diaphragm pump to operate in conjunction: first, the filter chamber of the filter press is filled by the screw pump, and then the pneumatic diaphragm pump is switched to feed the sludge. The pneumatic diaphragm pump is used to fill the remaining gaps in the filter chamber by utilizing its pressure-holding characteristic, thus completing the filtration. 5) The filtrate produced by the filter press is discharged into the filtrate collection tank, and the filtrate is transported to the wastewater collection tank by the filtrate delivery pump. The start and stop of the filtrate delivery pump is automatically controlled by the PLC control module according to the liquid level signal of the filtrate collection tank. The entire process described above is automated through electrical programming, with PLC controlling the parameters of each step.

2. The deep treatment process for chip grinding wastewater concentrate according to claim 1, characterized in that, In step (1), the preset multiple pH target values ​​are 3-6 sets, and the difference between two adjacent target values ​​is 0.5-2.0 pH units; the gradient switching logic is as follows: when the pH value monitored by the online pH meter deviates from the current preset target value by less than or equal to ±0.2 pH units, the PLC program automatically switches to the next set of pH target values ​​and adjusts the dosage accordingly; the online pH meter monitors once every 1-5 seconds to ensure timely capture of pH value changes; the recorded data includes, but is not limited to, pH adjustment time, real-time pH value, dosage at each gradient switch, number of gradient switches and corresponding time points, and all data are stored in the storage unit of the PLC control module.

3. The deep treatment process for chip grinding wastewater concentrate according to claim 1, characterized in that, In step (2), the dosing pump is a metering pump with a flow rate adjustment accuracy of ±1%, which can accurately control the dosage of PAC. The pneumatic diaphragm valve forms a linkage and interlock mechanism with the dosing pump. When the dosing pump stops running, the pneumatic diaphragm valve automatically closes to prevent leakage or backflow of the agent. The PLC dynamically adjusts the stroke and frequency of the metering pump in real time according to the signal fed back by the wastewater flow sensor at the outlet of the pH adjustment unit, so that the dosage of PAC matches the wastewater flow rate and ensures that the concentration of PAC in the wastewater is stable within the preset range of 0.1-0.5 g / L. At the same time, a pressure sensor is installed in the pipeline of the PAC dosing unit. When the pipeline pressure exceeds 0.3 MPa, the PLC control module issues an alarm signal and automatically stops the dosing pump.

4. The deep treatment process for chip grinding wastewater concentrate according to claim 1, characterized in that, In step (3), the dosing pump is a variable dosing pump. The PLC adjusts the dosage of PAM according to the data monitored by the turbidity sensor of the mixed liquid at the outlet of the PAC dosing unit, according to a preset ratio. When the turbidity of the mixed liquid is between 100-300 NTU, the mass ratio of PAM dosage to PAC dosage is 1:0.2-1:0.

3. When the turbidity is >300 NTU, the ratio is adjusted to 1:0.3-1:0.

5. When the turbidity is <100 NTU, the ratio is adjusted to 1:0.1-1:0.2, so as to ensure that the formed flocs are uniform in size and compact in structure, with a particle size range of 0.5-2 mm, thereby improving the efficiency of subsequent pressure filtration. The mass ratio of PAM dosage to PAC dosage is between 1:0.1-1:0.5, and the operating status and dosage of the dosing pump are recorded by the PLC in real time.

5. The deep treatment process for chip grinding wastewater concentrate according to claim 1, characterized in that, In step (4), the flow rate of the screw pump is 10-50 m³ / h. During the feeding process into the filter chamber of the filter press, the PLC monitors the feeding situation in real time through the flow sensor and pressure sensor installed at the feed inlet of the filter press. When the filter chamber is detected to be filled to 75%-85% of the space, the PLC sends a signal to stop the operation of the screw pump. Then, the pneumatic diaphragm pump is started. The working pressure range of the pneumatic diaphragm pump is 0.6-1.2 MPa. Using its pressure-holding function, the remaining gaps in the filter chamber are completely filled. During the filtration process, the PLC monitors the filter chamber pressure and liquid output parameters of the filter press in real time. When the liquid output is less than 0.5 m³ / h for 5 consecutive minutes, it is determined that the preset filtration endpoint condition has been reached and the filtration process is automatically stopped.

6. The deep treatment process for chip grinding wastewater concentrate according to claim 1, characterized in that, In step (5), the filtrate collection tank is equipped with a liquid level sensor. When the liquid level reaches 60%-80% of the collection tank volume, the liquid level sensor sends a signal to the PLC control module, and the PLC controls the filtrate delivery pump to start automatically. When the liquid level is lower than 20% of the collection tank volume, the PLC controls the filtrate delivery pump to stop automatically. The filtrate collection tank is also equipped with a stirring device, which is controlled by the PLC to start intermittently. The stirring frequency is once per hour, and each stirring lasts for 5 minutes to prevent sedimentation in the collection tank.

7. A deep treatment system for chip grinding wastewater concentrate implementing the process described in any one of claims 1-6, characterized in that, include: 1) pH adjustment unit: It consists of a pH adjustment tank, an online pH meter, two sets of pH adjustment agent storage tanks, corresponding dosing pumps and pipelines. The online pH meter is installed in the pH adjustment tank to monitor the pH value of the concentrate in the tank in real time. Its signal output terminal is electrically connected to the PLC control module. The control terminal of the dosing pump is electrically connected to the PLC control module. The PLC control module controls the operation of the dosing pump according to the monitoring data of the online pH meter to realize the quantitative addition of pH adjustment agent. 2) PAC dosing unit: includes a PAC storage tank, a metering pump, a pneumatic diaphragm valve, and connecting pipelines. The inlet of the metering pump is connected to the PAC storage tank through a pipeline, and the outlet is connected to the outlet pipeline of the pH adjustment unit through a pipeline connected to the pneumatic diaphragm valve. The control terminals of the metering pump and the pneumatic diaphragm valve are electrically connected to the PLC control module, which controls the quantitative dosing of PAC and the opening and closing of the pipeline. 3) PAM dosing unit: It consists of a PAM storage tank, a variable dosing pump and connecting pipelines. The inlet of the variable dosing pump is connected to the PAM storage tank, and the outlet is connected to the outlet pipeline of the PAC dosing unit through the pipeline. The control terminal of the variable dosing pump is electrically connected to the PLC control module. The PLC control module controls the dosing of PAM according to relevant monitoring data. 4) High-pressure diaphragm filter press unit: This unit includes a high-pressure diaphragm filter press, a screw pump, a pneumatic diaphragm pump, a pressure sensor, a flow sensor, and connecting pipelines. The inlets of the screw pump and the pneumatic diaphragm pump are connected to the outlet pipeline of the PAM dosing unit via pipelines, and their outlets are connected to the feed inlet of the high-pressure diaphragm filter press. The pressure sensor and the flow sensor are installed on the feed pipeline of the filter press, and their signal output terminals are electrically connected to the PLC control module. The control terminals of the screw pump and the pneumatic diaphragm pump are electrically connected to the PLC control module. The PLC control module controls the coordinated operation of the screw pump and the pneumatic diaphragm pump based on the monitoring data from the sensors. 5) Filtrate treatment unit: includes a filtrate collection tank, a filtrate transfer pump, and a wastewater collection tank. The inlet of the filtrate collection tank is connected to the filtrate outlet of the high-pressure diaphragm filter press via a pipeline. The outlet of the filtrate collection tank is connected to the inlet of the filtrate transfer pump via a pipeline. The outlet of the filtrate transfer pump is connected to the wastewater collection tank via a pipeline. A liquid level sensor is installed inside the filtrate collection tank. The liquid level sensor and the filtrate transfer pump are both electrically connected to the PLC control module. 6) PLC Control Module: The human-machine interface and data storage unit are electrically connected to the electrical equipment in the pH adjustment unit, PAC dosing unit, PAM dosing unit, high-pressure diaphragm filter press unit, and filtrate treatment unit, respectively. It receives monitoring data from each sensor, controls the operating parameters of each device according to a preset program, and records relevant data throughout the entire processing. The human-machine interface can display the operating status, monitoring parameters, and historical data curves of each unit in real time. Operators can set relevant parameters and modify the control program through this interface. The data storage unit stores all monitoring data and operation records during system operation for at least 6 months to facilitate subsequent process analysis and troubleshooting.

8. The chip grinding wastewater concentrate deep treatment system according to claim 7, characterized in that, The pH adjustment unit is equipped with a stirring device in the pH adjustment tank. The control terminal of the stirring device is electrically connected to the PLC control module. The PLC control module controls the start, stop and stirring speed of the stirring device according to the liquid volume in the pH adjustment tank or the pH adjustment process. The stirring speed can be adjusted in the range of 100-300 r / min. When the pH value gradient changes, the stirring speed automatically increases to 200-300 r / min to accelerate the mixing of the reagent and the concentrate. When the pH value is stable, the stirring speed decreases to 100-200 r / min to save energy.

9. The chip grinding wastewater concentrate deep treatment system according to claim 7, characterized in that, Both the PAC and PAM dosing units are equipped with level sensors and concentration sensors on their storage tanks. The level sensors monitor the drug level, and when the drug level in the storage tank falls below the preset minimum level, the PLC control module issues an alarm signal to remind the operator to replenish the drug in time. The concentration sensors monitor the drug concentration, and when the concentration falls below the preset value, the PLC control module also issues an alarm signal. In addition, the storage tanks are equipped with a stirring device, which is automatically activated by the PLC at a frequency of 10 minutes every 30 minutes to prevent drug sedimentation.

10. The chip grinding wastewater concentrate deep treatment system according to claim 7, characterized in that, The high-pressure diaphragm filter press unit also includes a filter cake thickness sensor, which is installed on the filter plate of the high-pressure diaphragm filter press to monitor the thickness of the filter cake. Its signal output terminal is electrically connected to the PLC control module. When the filter cake thickness reaches the preset value, the PLC control module determines that the filter press is saturated, automatically controls the stopping of mud feeding, and enters the pressing stage. After pressing is completed, the PLC control module controls the opening of the filter press, cake unloading, and other actions according to the preset program to realize automated operation.