Pretreatment device and method for wastewater containing heavy metal ions

Abstract

The invention relates to the technical field of wastewater treatment, and provides a pretreatment device and method for wastewater containing heavy metal ions, and the pretreatment device comprises a water inlet unit, a multi-stage reaction unit, a solid-liquid separation unit, a deep adsorption unit and an intelligent control unit; the water inlet unit comprises a wastewater storage pool and a pH adjusting pool, and the pH adjusting pool is provided with a pH sensor and a dosing device; the multi-stage reaction unit consists of three rotational flow reaction tanks which are connected in series, and spiral guide plates are arranged in the tanks to enhance mixing; the solid-liquid separation unit comprises an inclined plate sedimentation tank and a centrifugal filter; a sludge return pipe is arranged at the bottom of the inclined plate sedimentation tank and extends to the reaction tank; the deep adsorption unit is filled with a modified zeolite-activated carbon composite adsorbent, and a heavy metal ion concentration online monitor is arranged at the rear end; the intelligent control unit dynamically adjusts the dosage and the reaction time based on pH and concentration data. The device has the beneficial effects that the mixing efficiency of wastewater treatment is enhanced, the pH application range of wastewater treatment is widened, and the cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of wastewater treatment, and in particular to a pretreatment device and method for wastewater containing heavy metal ions. Background Art

[0002] Industrial wastewater refers to wastewater, sewage, and waste liquids generated during industrial production. These wastewater contains industrial materials, intermediates, and finished products lost to water, as well as pollutants generated during the production process. With the rapid development of industry, the types of wastewater are increasing, and the amount of wastewater containing heavy metal ions is increasing. Because heavy metal ions are difficult to degrade under natural conditions, they can pollute water sources, soil, and other environmental sources.

[0003] Currently, commonly used treatment methods include chemical precipitation, adsorption, ion exchange, etc., but there are the following problems:

[0004] 1. Chemical precipitation requires excessive dosage of chemicals, which easily produces a large amount of heavy metal-containing sludge and high treatment costs;

[0005] 2. The adsorption method has poor effect on low-concentration wastewater and the adsorption material is difficult to regenerate.

[0006] Therefore, there is an urgent need for a pretreatment device and method that is efficient, low-consumption and highly adaptable. Summary of the Invention

[0007] The present invention provides a pretreatment device and method for wastewater containing heavy metal ions, aiming to solve the above problems.

[0008] The present invention is achieved by providing a pretreatment device and method for wastewater containing heavy metal ions, wherein the pretreatment device for wastewater containing heavy metal ions comprises: a water inlet unit, a multi-stage reaction unit, a solid-liquid separation unit, a deep adsorption unit and an intelligent control unit;

[0009] The water inlet unit includes a wastewater storage tank and a pH adjustment tank, and the pH adjustment tank is equipped with a pH sensor and a dosing device;

[0010] The multi-stage reaction unit consists of three cyclone reaction tanks connected in series. The tanks are equipped with spiral guide plates to enhance mixing. Each tank is connected to a composite precipitant dosing device.

[0011] The solid-liquid separation unit includes an inclined plate sedimentation tank and a centrifugal filter. A sludge return pipe is provided at the bottom of the inclined plate sedimentation tank.

[0012] The deep adsorption unit is filled with a modified zeolite-activated carbon composite adsorbent, and an online heavy metal ion concentration monitor is set at the back end;

[0013] The intelligent control unit dynamically adjusts the dosage and reaction time based on pH value and heavy metal ion concentration data.

[0014] Preferably, the wastewater storage tank is used to temporarily store wastewater to be treated, and a liquid level meter and a lifting pump are provided in the wastewater storage tank. The liquid level meter is used to obtain the water level of the wastewater in the wastewater storage tank, and the lifting pump is used to transport the wastewater in the wastewater storage tank to the pH adjustment tank through a pipeline; the pH sensor is arranged on the inner wall of the pH adjustment tank, and the pH sensor is used to monitor the pH value of the wastewater in the tank in real time. The pH adjustment tank has a built-in mechanical stirrer.

[0015] Preferably, the dosing device includes an acidic agent storage tank, an alkaline agent storage tank and two metering pumps. The acidic agent storage tank and the alkaline agent storage tank are respectively connected to the outer wall of the pH regulating tank. One end of the two metering pumps is connected to the pH regulating tank, and the other end is connected to the acidic agent storage tank and the alkaline agent storage tank respectively. The acidic agent storage tank and the alkaline agent storage tank add acid and alkaline agents to the pH regulating tank through the metering pumps.

[0016] Preferably, a dosing port is provided on the top of the tank body of the cyclone reaction tank, which is connected to a composite precipitant dosing device. The composite precipitant dosing device contains sodium sulfide and polyferric sulfate solution. An ultrasonic liquid level sensor is provided in the composite precipitant dosing device, which is used to monitor the liquid level in the tank to prevent overflow. A plurality of spiral guide plates are provided on the inner wall of the tank body, and the plurality of spiral guide plates are evenly distributed in a spiral along the tank wall to form a cyclone channel to enhance mixing efficiency.

[0017] Preferably, the three cyclone reaction tanks connected in series are a primary reaction tank, a secondary reaction tank and a tertiary reaction tank, respectively. The water inlet of the primary reaction tank is connected to the water outlet of the pH adjustment tank through a pipe, and the reaction tanks at each level are connected by flanges, adopting a "bottom-in and top-out" flow design to ensure step-by-step reaction.

[0018] Preferably, a multi-layer inclined plate group is provided inside the inclined plate sedimentation tank, and a conical sludge hopper and a sludge discharge valve are provided at the bottom. The water inlet end of the inclined plate sedimentation tank receives the effluent from the third-stage reaction tank through a pipeline, and the supernatant in the third-stage reaction tank enters the centrifugal filter through the overflow weir. The sludge hopper is connected to the dosing area of ​​the first-stage reaction tank through a sludge return pipe to realize sludge recycling.

[0019] Preferably, the supernatant after centrifugal filtration flows out from the water outlet of the centrifugal filter, and the sludge outlet of the centrifugal filter is connected to a sludge concentration tank.

[0020] Preferably, the deep adsorption unit includes an adsorption tower, the interior of the adsorption tower is divided into three layers, the upper layer is filled with modified zeolite, the middle layer is filled with activated carbon, and the lower layer is filled with quartz sand as a support layer. The water inlet end of the adsorption tower is connected to the outlet pipe of the centrifugal filter, and the outlet of the adsorption tower is connected to a recovery pipe. The other end of the recovery pipe is connected to the pH adjustment tank. A water outlet pipe is connected next to the recovery pipe. A heavy metal ion concentration online monitor and a solenoid valve are installed at one end of the outlet pipe close to the recovery pipe. The heavy metal ion concentration online monitor detects the residual concentration of heavy metals in real time. If the heavy metal ion concentration reaches the discharge standard, the solenoid valve is opened to discharge the qualified water.

[0021] Preferably, the intelligent control unit includes a PLC controller and a data acquisition module. The PLC controller controls the operation of the entire pretreatment device. The data acquisition module is connected to the pH sensor, concentration monitor and liquid level meter, and transmits the collected data to the PLC controller. The PLC controller automatically adjusts the dosage of the first dosing pump according to the feedback from the pH sensor, and dynamically adjusts the dosing frequency and centrifuge speed of the three cyclone reaction tanks based on the concentration monitor data. The PLC controller communicates with the host computer to realize remote monitoring and data storage.

[0022] A pretreatment method for wastewater containing heavy metal ions, comprising the following steps:

[0023] Step 1: The wastewater in the wastewater storage tank enters the pH adjustment tank through the lifting pump. The pH sensor detects the pH value of the wastewater and transmits it to the PLC controller through the data acquisition module. According to the received pH value, the PLC controller controls the dosing device to add acidic solution or alkaline solution to the pH adjustment tank to adjust the pH value of the wastewater to 8-9;

[0024] Step 2: The wastewater after pH adjustment is passed into a multi-stage reaction unit, and flows through the primary reaction tank, the secondary reaction tank, and the tertiary reaction tank in sequence. Polyferric sulfate and polyacrylamide are added in stages in the cyclone reaction tank to enhance flocculation;

[0025] Step 3: The effluent from the third-stage reaction tank enters the inclined plate sedimentation tank through a pipeline. The sludge hopper transports the sludge to the dosing area of ​​the first-stage reaction tank through the sludge return pipe to realize sludge recycling. The supernatant in the tank enters the centrifugal filter through the overflow weir. After the precipitated sludge is centrifugally dehydrated, the supernatant is transported from the water outlet of the centrifugal filter to the deep adsorption unit, and the sludge is transported from the sludge outlet of the centrifugal filter to the sludge thickening tank;

[0026] Step 4: The adsorption unit further removes residual ions from the supernatant of the centrifugal filter. The saturated adsorption material is regenerated with dilute hydrochloric acid. The heavy metal ion concentration online monitor detects the residual heavy metal concentration in the outlet pipe in real time. If the heavy metal ion concentration does not meet the standard, the regenerated liquid flows back to the pH adjustment tank from the recovery pipe and is reused in step 1. If the heavy metal ion concentration meets the discharge standard, the solenoid valve is opened to discharge the qualified water.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. Enhanced mixing efficiency: The multi-stage swirl reaction design is adopted to form turbulence through the spiral guide plate, thereby improving the utilization rate of the reagent;

[0029] 2. Broaden the pH adaptability range: Adopting a composite precipitant formula, sodium sulfide and polyferric sulfate work synergistically to broaden the pH adaptability range of wastewater treatment;

[0030] 3. Reduce costs: Sludge return and chemical regeneration reduce chemical consumption and sludge volume. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 1 is an overall connection diagram of an embodiment of the present invention;

[0033] Figure 2 1 is a schematic cross-sectional structural diagram of a water inlet unit according to an embodiment of the present invention;

[0034] Figure 3 Schematic diagram of the cross-sectional structure of a cyclone reaction tank according to an embodiment of the present invention;

[0035] Figure 4 Schematic diagram of the cross-sectional structure of the inclined plate sedimentation tank according to an embodiment of the present invention;

[0036] Figure 5 It is a schematic diagram of the cross-sectional structure of the deep adsorption unit according to an embodiment of the present invention.

[0037] The markings in the accompanying drawings are: 1. Wastewater storage tank; 101. Liquid level meter; 102. Lifting pump; 2. pH adjustment tank; 201. pH sensor; 202. Dosing device; 203. Mechanical agitator; 3. Cyclone reaction tank; 301. Primary reaction tank; 302. Secondary reaction tank; 303. Tertiary reaction tank; 304. Composite precipitant dosing device; 305. Ultrasonic liquid level sensor; 306. Spiral guide plate; 4. Inclined plate sedimentation tank; 401. Inclined plate group; 402. Conical sludge hopper; 403. Sludge discharge valve; 5. Centrifugal filter; 6. Adsorption tower; 601. Modified zeolite; 602. Activated carbon; 603. Quartz sand; 7. Recovery pipeline; 8. Outlet pipe; 9. Heavy metal ion concentration online monitor; 10. Solenoid valve. DETAILED DESCRIPTION

[0038] In order to more fully understand the technical content of the present invention, the technical solution of the present invention is further introduced and illustrated in conjunction with specific embodiments below, but is not limited thereto. The technical solution in the embodiment of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiment of the present invention. Obviously, the described embodiment is only a part of the embodiment of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0039] refer to Figures 1 to 5 , the pretreatment device for wastewater containing heavy metal ions includes: a water inlet unit, a multi-stage reaction unit, a solid-liquid separation unit, a deep adsorption unit and an intelligent control unit;

[0040] The water inlet unit includes a wastewater storage tank 1 and a pH adjustment tank 2. The pH adjustment tank 2 is equipped with a pH sensor 201 and a dosing device 202.

[0041] The wastewater storage tank 1 is used to temporarily store wastewater to be treated. A liquid level meter 101 and a lifting pump 102 are provided in the wastewater storage tank 1. The liquid level meter 101 is used to obtain the water level of the wastewater in the wastewater storage tank 1. The lifting pump 102 is used to transport the wastewater in the wastewater storage tank 1 to the pH regulating tank 2 through a pipeline. A pH sensor 201 is provided on the inner wall of the pH regulating tank 2. The pH sensor 201 is used to monitor the pH value of the wastewater in the tank in real time. The dosing device 202 includes an acidic agent storage tank, an alkaline agent storage tank and two metering pumps. The acidic agent storage tank and the alkaline agent storage tank are respectively connected to the outer wall of the pH adjusting tank 2. One end of the two metering pumps is connected to the pH adjusting tank 2, and the other ends are respectively connected to the acidic agent storage tank and the alkaline agent storage tank. The acidic agent storage tank and the alkaline agent storage tank add acid and alkaline agents to the pH adjusting tank 2 through the metering pumps. The pH adjusting tank 2 has a built-in mechanical stirrer 203. When adjusting the pH value of the wastewater, the mechanical stirrer 203 is used to stir the wastewater and the acid and alkaline agents so that the wastewater and the acid and alkaline agents are fully blended.

[0042] The multi-stage reaction unit consists of three cyclone reaction tanks 3 connected in series, with spiral guide plates 306 inside the tanks to enhance mixing, and each tank is connected to a composite precipitant dosing device 304;

[0043] A dosing port is provided on the top of the cyclone reaction tank 3, which is connected to a composite precipitant dosing device 304. The composite precipitant dosing device 304 contains sodium sulfide and polyferric sulfate solution. An ultrasonic liquid level sensor 305 is provided in the composite precipitant dosing device 304 for monitoring the liquid level in the tank to prevent overflow. A plurality of spiral guide plates 306 are provided on the inner wall of the tank. The plurality of spiral guide plates 306 are evenly distributed along the tank wall in a spiral pattern to form a cyclone channel to enhance mixing efficiency. The three cyclone reaction tanks 3 connected in series are a primary reaction tank 301, a secondary reaction tank 302, and a tertiary reaction tank 303. The water inlet of the primary reaction tank 301 is connected to the water outlet of the pH adjustment tank 2 via a pipe. The reaction tanks at each stage are connected by flanges, adopting a "bottom-in, top-out" flow design to ensure step-by-step reaction.

[0044] The solid-liquid separation unit includes an inclined plate sedimentation tank 4 and a centrifugal filter 5. A sludge return pipe is provided at the bottom of the inclined plate sedimentation tank 4 to the reaction tank;

[0045] A multi-layer inclined plate group 401 is provided inside the inclined plate sedimentation tank 4, and a conical sludge hopper 402 and a sludge discharge valve 403 are provided at the bottom. The water inlet end of the inclined plate sedimentation tank 4 receives the effluent from the third-stage reaction tank 303 through a pipeline, and the supernatant in the third-stage reaction tank 303 enters the centrifugal filter 5 through the overflow weir. The sludge hopper is connected to the dosing area of ​​the first-stage reaction tank 301 through a sludge return pipe to realize the recycling of sludge; the supernatant after centrifugal filtration flows out from the water outlet end of the centrifugal filter 5, and the sludge discharge port of the centrifugal filter 5 is connected to the sludge thickening tank.

[0046] The deep adsorption unit is filled with a modified zeolite 601-activated carbon 602 composite adsorbent, and an online heavy metal ion concentration monitor 9 is set at the back end;

[0047] The deep adsorption unit includes an adsorption tower 6. The interior of the adsorption tower 6 is divided into three layers. The upper layer is filled with modified zeolite 601, the middle layer is filled with activated carbon 602, and the lower layer is filled with quartz sand 603 as a support layer. The water inlet end of the adsorption tower 6 is connected to the outlet pipe 8 of the centrifugal filter 5. The outlet of the adsorption tower 6 is connected to a recovery pipe 7. The other end of the recovery pipe 7 is connected to the pH adjustment tank 2. The recovery pipe 7 is connected to an outlet pipe 8. A heavy metal ion concentration online monitor 9 and a solenoid valve 10 are installed at one end of the outlet pipe 8 close to the recovery pipe 7. The heavy metal ion concentration online monitor 9 detects the residual concentration of heavy metals in real time. If the heavy metal ion concentration reaches the discharge standard, the solenoid valve 10 is opened to discharge the qualified water.

[0048] The intelligent control unit dynamically adjusts the dosage and reaction time based on pH and concentration data;

[0049] The intelligent control unit includes a PLC controller and a data acquisition module. The PLC controller controls the operation of the entire pretreatment device. The data acquisition module is connected to the pH sensor 201, the concentration monitor and the liquid level meter 101, and transmits the collected data to the PLC controller. The PLC controller automatically adjusts the dosage of the first dosing pump based on the feedback from the pH sensor 201, and dynamically adjusts the dosing frequency and centrifuge speed of the three cyclone reaction tanks 3 based on the concentration monitor data. The PLC controller communicates with the host computer to realize remote monitoring and data storage.

[0050] A pretreatment method for wastewater containing heavy metal ions, comprising the following steps:

[0051] Step 1: The wastewater in the wastewater storage tank 1 enters the pH adjustment tank 2 through the lift pump 102. The pH sensor 201 detects the pH value of the wastewater and transmits it to the PLC controller through the data acquisition module. Based on the received pH value, the PLC controller controls the dosing device 202 to add acidic solution or alkaline solution to the pH adjustment tank 2 to adjust the pH value of the wastewater to 8-9;

[0052] Step 2: The wastewater after pH adjustment is passed into a multi-stage reaction unit, and flows through the primary reaction tank 301, the secondary reaction tank 302, and the tertiary reaction tank 303 in sequence. Polyferric sulfate and polyacrylamide are added in stages in the cyclone reaction tank 3 to enhance flocculation.

[0053] Step 3: The effluent from the third-stage reaction tank 303 enters the inclined plate sedimentation tank 4 through a pipeline. The sludge hopper transports the sludge to the dosing area of ​​the first-stage reaction tank 301 through the sludge return pipe to achieve sludge recycling. The supernatant in the tank enters the centrifugal filter 5 through the overflow weir. After the precipitated sludge is centrifugally dehydrated, the supernatant is transported from the water outlet of the centrifugal filter 5 to the deep adsorption unit. The sludge is then transported from the sludge outlet of the centrifugal filter 5 to the sludge thickening tank.

[0054] Step 4: The adsorption unit further removes residual ions from the supernatant of the centrifugal filter 5. The saturated adsorption material is regenerated with dilute hydrochloric acid. The heavy metal ion concentration online monitor 9 detects the residual heavy metal concentration in the water pipe 8 in real time. If the heavy metal ion concentration does not meet the standard, the regenerated liquid flows back to the pH adjustment tank 2 from the recovery pipe 7 and is reused in step 1. If the heavy metal ion concentration meets the discharge standard, the solenoid valve 10 is opened to discharge the qualified water.

[0055] The embodiments described above are only part of the embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any ordinary technician in the field, within the technical scope disclosed by the present invention, can make equivalent replacements or changes based on the technical solutions and inventive concepts of the present invention, which should be covered by the scope of protection of the present invention.

Claims

1. A pretreatment device for wastewater containing heavy metal ions, characterized in that: The pretreatment device for wastewater containing heavy metal ions comprises: a water inlet unit, a multi-stage reaction unit, a solid-liquid separation unit, a deep adsorption unit and an intelligent control unit; The water inlet unit includes a wastewater storage tank (1) and a pH adjustment tank (2), wherein the pH adjustment tank (2) is equipped with a pH sensor (201) and a dosing device (202); The multi-stage reaction unit is composed of three cyclone reaction tanks (3) connected in series, wherein a spiral guide plate (306) is provided inside the tank to enhance mixing, and each tank is connected to a composite precipitant dosing device (304); The solid-liquid separation unit comprises an inclined plate sedimentation tank (4) and a centrifugal filter (5), and a sludge return pipe is provided at the bottom of the inclined plate sedimentation tank (4); The deep adsorption unit is filled with a modified zeolite (601)-activated carbon (602) composite adsorbent, and a heavy metal ion concentration online monitor (9) is provided at the rear end; The intelligent control unit dynamically adjusts the dosage and reaction time based on pH value and heavy metal ion concentration data.

2. The pretreatment device for wastewater containing heavy metal ions according to claim 1, characterized in that: The wastewater storage tank (1) is used for temporarily storing wastewater to be treated. A liquid level meter (101) and a lifting pump (102) are provided in the wastewater storage tank (1). The liquid level meter (101) is used to obtain the water level of the wastewater in the wastewater storage tank (1). The lifting pump (102) is used to transport the wastewater in the wastewater storage tank (1) to the pH regulating tank (2) through a pipeline. A pH sensor (201) is provided on the inner wall of the pH regulating tank (2). The pH sensor (201) is used to monitor the pH value of the wastewater in the tank in real time. The pH regulating tank (2) has a built-in mechanical stirrer (203).

3. The pretreatment device for wastewater containing heavy metal ions according to claim 1, characterized in that: The dosing device (202) comprises an acidic agent storage tank, an alkaline agent storage tank and two metering pumps. The acidic agent storage tank and the alkaline agent storage tank are respectively connected to the outer wall of the pH regulating tank (2). One end of the two metering pumps is connected to the pH regulating tank (2), and the other end is respectively connected to the acidic agent storage tank and the alkaline agent storage tank. The acidic agent storage tank and the alkaline agent storage tank add acid and alkaline agents into the pH regulating tank (2) through the metering pumps.

4. The pretreatment device for wastewater containing heavy metal ions according to claim 1, characterized in that: The top of the cyclone reaction tank (3) is provided with a drug adding port, which is communicated with a composite precipitant adding device (304). The composite precipitant adding device (304) contains sodium sulfide and polyferric sulfate solution. The composite precipitant adding device (304) is provided with an ultrasonic liquid level sensor (305), which is used to monitor the liquid level in the tank to prevent overflow. The inner wall of the tank is provided with a plurality of spiral guide plates (306), which are evenly distributed in a spiral along the tank wall to form a cyclone channel to enhance mixing efficiency.

5. The pretreatment device for wastewater containing heavy metal ions according to claim 1, characterized in that: The three cyclone reaction tanks (3) connected in series are a primary reaction tank (301), a secondary reaction tank (302) and a tertiary reaction tank (303) in sequence. The water inlet of the primary reaction tank (301) is connected to the water outlet of the pH regulating tank (2) through a pipeline. The reaction tanks at each level are connected by flanges, and a "bottom-in, top-out" flow direction design is adopted to ensure step-by-step reaction.

6. The pretreatment device for wastewater containing heavy metal ions according to claim 1, characterized in that: The inclined plate sedimentation tank (4) is provided with a multi-layer inclined plate group (401) inside, and a conical sludge hopper (402) and a sludge discharge valve (403) are provided at the bottom. The water inlet end of the inclined plate sedimentation tank (4) receives the effluent of the third-stage reaction tank (303) through a pipeline. The supernatant in the third-stage reaction tank (303) enters the centrifugal filter (5) through the overflow weir. The sludge hopper is connected to the dosing area of ​​the first-stage reaction tank (301) through a sludge return pipe, thereby realizing sludge recycling.

7. The pretreatment device for wastewater containing heavy metal ions according to claim 1, characterized in that: The supernatant of the centrifugal filter (5) flows out from the water outlet, and the mud outlet of the centrifugal filter (5) is connected to a sludge concentration tank.

8. The pretreatment device for wastewater containing heavy metal ions according to claim 1, characterized in that: The deep adsorption unit comprises an adsorption tower (6). The interior of the adsorption tower (6) is divided into three layers, the upper layer is filled with modified zeolite (601), the middle layer is filled with activated carbon (602), and the lower layer is filled with quartz sand (603) as a support layer. The water inlet end of the adsorption tower (6) is connected to the outlet pipe (8) of the centrifugal filter (5). The outlet of the adsorption tower (6) is connected to a recovery pipe (7). The other end of the recovery pipe (7) is connected to the pH regulating tank (2). The recovery pipe (7) is connected to the outlet pipe (8). A heavy metal ion concentration online monitor (9) and a solenoid valve (10) are installed at one end of the outlet pipe (8) close to the recovery pipe (7). The heavy metal ion concentration online monitor (9) detects the heavy metal residual concentration in real time. If the heavy metal ion concentration reaches the discharge standard, the solenoid valve (10) is opened to discharge the qualified water.

9. The pretreatment device for wastewater containing heavy metal ions according to claim 1, characterized in that: The intelligent control unit comprises a PLC controller and a data acquisition module. The PLC controller regulates the operation of the entire pretreatment device. The data acquisition module is connected to the pH sensor (201), the concentration monitor and the liquid level meter (101), and transmits the collected data to the PLC controller. The PLC controller automatically adjusts the dosage of the first dosing pump according to feedback from the pH sensor (201), and dynamically adjusts the dosing frequency and centrifuge speed of the three cyclone reaction tanks (3) based on the concentration monitor data. The PLC controller communicates with the host computer to realize remote monitoring and data storage.

10. The method for pretreating wastewater containing heavy metal ions according to any one of claims 1 to 9, characterized in that: Includes the following: Step 1: The wastewater in the wastewater storage tank (1) enters the pH adjustment tank (2) through the lifting pump (102), the pH sensor (201) detects the pH value of the wastewater and transmits it to the PLC controller through the data acquisition module. According to the received pH value, the PLC controller controls the dosing device (202) to add acidic solution or alkaline solution into the pH adjustment tank (2) to adjust the pH value of the wastewater to 8-9; Step 2: The wastewater after pH adjustment is passed through a multi-stage reaction unit, and flows through a primary reaction tank (301), a secondary reaction tank (302), and a tertiary reaction tank (303) in sequence, and polyferric sulfate and polyacrylamide are added in stages in a cyclone reaction tank (3) to enhance flocculation; Step 3: The effluent from the third-stage reaction tank (303) enters the inclined plate sedimentation tank (4) through a pipeline, and the sludge hopper transports the sludge to the dosing area of ​​the first-stage reaction tank (301) through the sludge return pipe to realize sludge recycling. The supernatant in the tank enters the centrifugal filter (5) through the overflow weir. After the precipitated sludge is centrifugally dehydrated, the supernatant is transported from the water outlet of the centrifugal filter (5) to the deep adsorption unit, and the sludge is transported from the sludge outlet of the centrifugal filter (5) to the sludge thickening tank; Step 4: The adsorption unit further removes residual ions from the supernatant of the centrifugal filter (5). The saturated adsorption material is regenerated with dilute hydrochloric acid. The heavy metal ion concentration online monitor (9) detects the heavy metal residual concentration in the outlet pipe (8) in real time. If the heavy metal ion concentration does not meet the standard, the regenerated liquid flows back to the pH adjustment tank (2) from the recovery pipe (7) and is reused in step 1. If the heavy metal ion concentration meets the discharge standard, the solenoid valve (10) is opened to discharge the qualified water.

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