Semiconductor grinding wastewater treatment zero-emission system

Abstract

The utility model relates to wastewater treatment and resource recovery technical field especially, it is a kind of semiconductor grinding wastewater treatment zero emission system. It includes wastewater collection unit, centrifugal separation unit, transfer regulating unit, centrifugal separation unit, membrane filtration unit, low temperature evaporation unit, bag filter unit, reuse water storage unit. The utility model has the beneficial effect that: the preliminary processing of centrifugal separation unit in this technical scheme, significantly reduced the subsequent ceramic membrane filtration unit operating load, reduce the frequency of membrane pollution occurrence;Through the high-precision separation of ceramic membrane filtration unit, the effective removal of suspended solids, heavy metal ions, microorganisms and organic matter in wastewater is realized;Through the low-temperature difference evaporation technology of low-temperature evaporation unit, energy consumption is reduced and the operation stability of system is improved;Through the water quality monitoring device of reuse water storage and reuse unit, the stability of reuse water quality is ensured.

Description

Technical Field

[0001] This utility model relates to the field of wastewater treatment and resource recycling technology, and in particular to a zero-discharge system for semiconductor grinding wastewater treatment. Background Technology

[0002] In semiconductor manufacturing, polishing is a crucial step in ensuring that the wafer surface achieves a specific degree of flatness and smoothness, providing a foundation for subsequent circuit fabrication. However, the polishing process generates a large amount of wastewater containing various chemicals, fine particulate matter (such as silicon powder and metal ions), and other pollutants. These substances not only pollute water bodies but also threaten ecological and environmental safety.

[0003] Existing technology, patent application number CN2023215762708, discloses a semiconductor grinding wastewater treatment system. This wastewater treatment method mainly relies on processes such as physicochemical sedimentation tanks. Although it can reduce pollutant concentrations to a certain extent, it suffers from problems such as large sludge production, high chemical dosage, large footprint, and high operating costs. Furthermore, traditional processes struggle to achieve zero wastewater discharge, meaning some pollutants may still be released into the environment, failing to meet current demands for energy conservation, emission reduction, and resource recycling.

[0004] Furthermore, in actual operation, traditional processes often require the addition of large amounts of chemical agents to improve treatment efficiency. This not only increases the risk of salt accumulation but also further increases operating costs and the possibility of secondary pollution. Therefore, developing an efficient and stable grinding wastewater treatment technology that can achieve zero wastewater discharge, reduce operating costs, and improve effluent quality has become an urgent technical challenge. This invention aims to solve the above problems through innovative combined process design, providing technical support for the sustainable development of the semiconductor industry. Utility Model Content

[0005] The purpose of this invention is to provide a zero-discharge system for semiconductor grinding wastewater treatment, so as to overcome the above-mentioned shortcomings of the existing technology.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A zero-discharge system for treating semiconductor grinding wastewater, comprising:

[0008] The wastewater collection unit is used to receive grinding wastewater generated during semiconductor manufacturing. It has an inclined bottom design and is equipped with a drain outlet.

[0009] The centrifugal separation unit is connected to the wastewater collection unit via a pipeline, and is equipped with a centrifuge and a sludge collection hopper inside.

[0010] The intermediate regulating unit is connected to the centrifugal separation unit via a pipeline and is equipped with a liquid level sensor and a stirring device inside.

[0011] The membrane filtration unit is connected to the transfer and regulation unit via a pipe and contains multiple sets of ceramic membrane modules.

[0012] The low-temperature evaporation unit is connected to the concentrate outlet of the membrane filtration unit via a pipe, and is equipped with a heat exchange tube bundle and a condensation device inside.

[0013] The bag filter unit is connected to the condensate outlet of the low-temperature evaporation unit via a pipe, and contains multiple sets of filter bags.

[0014] The recycled water storage unit is connected to the bag filter unit via a pipe and is equipped with a water quality monitoring device inside.

[0015] The concentrate recirculation system is used to recirculate the concentrate from the membrane filtration unit back to the low-temperature evaporation unit.

[0016] Preferably, the inner wall of the collection tank of the wastewater collection unit is coated with a corrosion-resistant coating made of epoxy resin material, and a sealing cover is provided on the top of the collection tank.

[0017] Preferably, the stirring device of the transfer regulating unit adopts a double-layer blade design, and the diameter of the upper blade is larger than that of the lower blade.

[0018] Preferably, the pore size of the ceramic membrane module is in the range of 0.01 micrometers to 0.1 micrometers.

[0019] Preferably, the filter bag is made of polyester fiber material with a pore size of 1 micrometer and is fixed in the filter chamber by a snap fastener.

[0020] The beneficial effects of this utility model are as follows: The preliminary treatment by the centrifugal separation unit significantly reduces the operating load of the subsequent ceramic membrane filtration unit and decreases the frequency of membrane fouling; the high-precision separation by the ceramic membrane filtration unit effectively removes suspended solids, heavy metal ions, microorganisms, and organic matter from wastewater; the low-temperature differential evaporation technology of the low-temperature evaporation unit reduces energy consumption and improves the system's operational stability; and the water quality monitoring device for the recycled water storage and reuse unit ensures the stability of the recycled water quality.

[0021] This invention employs a combined process of "centrifugal separation + ceramic membrane filtration + low-temperature evaporation," with each unit seamlessly connected through a flow control device and a concentrate recirculation system, ensuring the continuity and stability of the wastewater treatment process.

[0022] The ceramic membrane filtration unit does not introduce additional salt, and combined with the desalination function of the low-temperature evaporation unit, the quality of the recycled water meets the production line reuse standards. The low-temperature heat pump evaporator operates under low temperature difference conditions, has low energy consumption and is not prone to scaling, and can achieve unattended operation, greatly reducing labor costs. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of a zero-discharge system for semiconductor grinding wastewater treatment according to the present invention.

[0024] Figure 2 This is a system layout block diagram of a zero-discharge system for semiconductor grinding wastewater treatment according to the present invention;

[0025] Figure 3 This is a schematic diagram of the low-temperature evaporation unit of a zero-discharge system for semiconductor grinding wastewater treatment according to this utility model;

[0026] Figure 4 This is a schematic diagram of the centrifugal separation unit of a zero-discharge system for semiconductor grinding wastewater treatment according to this utility model;

[0027] Figure 5 This utility model relates to a bag filter unit for a zero-discharge system for semiconductor grinding wastewater treatment;

[0028] In the diagram: 1. Wastewater collection unit; 2. Centrifugal separation unit; 3. Transfer and regulation unit; 4. Membrane filtration unit; 5. Low-temperature evaporation unit; 6. Bag filtration unit; 7. Reclaimed water storage unit; 8. Concentrate reflux system; 11. Collection tank; 12. Drain outlet; 13. Sealing cover. Detailed Implementation

[0029] Reference Figures 1 to 5 A zero-discharge system for semiconductor grinding wastewater treatment includes a wastewater collection unit 1, a centrifugal separation unit 2, a transfer and regulation unit 3, a membrane filtration unit 4, a low-temperature evaporation unit 5, a bag filter unit 6, a recycled water storage unit 7, and a concentrate recirculation system 8. These units are seamlessly connected through pipelines and flow control devices to ensure the continuity and stability of the wastewater treatment process.

[0030] Wastewater collection unit 1 is the starting part of the entire system, used to receive grinding wastewater generated during semiconductor manufacturing. This unit consists of a collection tank 11 with an inclined bottom and a drain outlet 12 at the lowest point, which is connected to the centrifugal separation unit 2 via a pipe. The inner wall of the collection tank is coated with a corrosion-resistant epoxy resin material, which effectively prevents chemicals in the wastewater from corroding the equipment. A sealing cover 13 is provided on the top of the collection tank, which is fixed to the tank body with bolts to prevent wastewater from evaporating and causing odors or secondary pollution. The side wall of the collection tank also has a water inlet, which is positioned higher than the drain outlet to ensure that the wastewater can flow naturally to the drain outlet under gravity. Grinding wastewater collection tank 1 is used to receive grinding wastewater generated during semiconductor manufacturing.

[0031] Centrifugal separation unit 2 is located after wastewater collection unit 1 and is used for preliminary treatment of wastewater. This unit includes a high-speed rotating centrifuge, a horizontal centrifuge (an existing structure). It utilizes the centrifugal force generated by high-speed rotation to separate suspended solids from water. The centrifugal force throws denser suspended solids and particulate matter onto the inner wall, forming sludge. This sludge is collected and processed externally, while the centrifugal liquid flows into a centrifugal liquid transfer tank. The centrifugal liquid transfer tank is equipped with a level sensor and a flow control device to monitor and adjust the liquid flow in real time, ensuring a stable operating load for subsequent treatment units. The discharge port is connected to the inlet pipe of transfer tank 31 via a flange. (See reference [link to reference] for details.) Figure 3 As shown.

[0032] The intermediate regulating unit 3, located after the centrifugal separation unit 2, is used for further regulating the wastewater after centrifugation. This unit includes an intermediate tank 31, which is equipped with a level sensor and a flow control valve. The level sensor is installed on the side wall of the intermediate tank and electrically connected to the control system, monitoring the liquid level in real time and transmitting the signal to the control system. The flow control valve is located on the outlet pipe of the intermediate tank and automatically adjusts the flow rate based on the feedback signal from the level sensor. A stirring device 32 is located at the bottom of the intermediate tank, driven by a geared motor. The stirring device employs a double-layer impeller design, with the upper impeller diameter larger than the lower impeller diameter to ensure uniform mixing of the liquid. The outlet pipe of the intermediate tank is connected to the inlet pipe of the membrane filtration unit 4 via a flange.

[0033] After flowing out of the transfer tank 3, the centrifuged liquid enters the membrane filtration unit 4 for advanced treatment. The membrane filtration unit 4 effectively removes suspended solids, heavy metal ions, microorganisms, and dissolved organic matter. The membrane filtration unit 4 is the core treatment unit of the OWUF membrane system, employing an external cylindrical membrane module and an external pressure cross-flow filtration method. The concentrate is returned to the pretreatment unit. The ultrafiltration membrane module has a nominal pore size of approximately 0.02 μm, offering the highest filtration accuracy among current PVDF ultrafiltration / microfiltration products, providing safe and reliable effluent quality. It also features a lower packing density, reducing sludge accumulation. A unique uniform straight-through water and air distribution design ensures smooth sludge discharge. Its unique mechanical structure, with a fixed outlet and a floating inlet, facilitates long-term stable operation of the membrane module. The filtrate permeates through the membrane channels into the recycled water storage unit 7, while the concentrate that does not permeate the membrane is circulated multiple times through the concentrate return system 8 before entering the low-temperature evaporation unit 5 for further treatment.

[0034] Membrane filtration unit 4 can consist of multiple ceramic membrane modules, each composed of multiple layers of ceramic material with a pore size ranging from 0.01 micrometers to 0.1 micrometers. The ceramic membrane modules are fixed to the filtration chamber via flanges. The filtration chamber has an inlet at the top and an outlet at the bottom. The inlet is connected to a transfer tank via a pipe, and the outlet is connected to a recycled water tank and a concentrate return system via pipes. The inner wall of the ceramic membrane module is coated with a hydrophobic coating made of polytetrafluoroethylene (PTFE) to reduce the likelihood of impurity adhesion. A backwashing device is installed outside the filtration chamber, connected to a cleaning pipe via a high-pressure water pump. The cleaning pipe has a nozzle at its end, which is used to backwash the surface of the ceramic membrane modules. The ceramic membrane modules are connected to the filtration chamber via quick-release couplings for easy replacement and maintenance.

[0035] The low-temperature evaporation unit 5, located after the membrane filtration unit 4, is used to evaporate the concentrated water after membrane filtration. This unit includes a low-temperature heat pump evaporator with a heat exchange tube bundle 51 inside. The outer wall of the heat exchange tube bundle is coated with an anti-scaling coating made of nano-scale materials, providing excellent anti-scaling performance. The evaporator is connected to a condenser 52, which is connected to the outside environment via a cooling water circulation system 53. A sludge removal device is located at the bottom of the evaporator, driven by an electric push rod, to periodically remove small amounts of sediment. The evaporator's inlet is connected to the concentrated water return system 8 via a pipe, and the condensate outlet is connected to a bag filter via a pipe.

[0036] The bag filter unit 6, located after the low-temperature evaporation unit 5, is used for further filtration of the condensate. This unit includes a filter chamber 61 containing multiple sets of filter bags 62, each with a pore size of 1 micrometer. The filter bags are secured inside the filter chamber with clips for easy replacement and cleaning. The filter chamber has an inlet 63 at the top and an outlet 64 at the bottom. The inlet is connected to the condensate outlet of the low-temperature evaporation unit via a pipe, and the outlet is connected to the recycled water tank via a pipe. The filter bags are made of polyester fiber material, offering good corrosion resistance and filtration accuracy.

[0037] The recycled water storage unit 7, located after the bag filter unit 6, is used to store treated recycled water. This unit includes a recycled water tank containing a water quality monitoring device, which includes a pH sensor, a conductivity sensor, and a suspended solids concentration sensor. The sensors are electrically connected to the control system via signal lines, monitoring water quality parameters in real time and transmitting the data to the control system. The recycled water tank has an overflow outlet at the top and a drain outlet at the bottom, which is connected to the production workshop's water supply system via a pipe.

[0038] The concentrate recirculation system 8 is located between the membrane filtration unit 4 and the low-temperature evaporation unit 5, and is used to recirculate the concentrate produced by the membrane filtration unit back to the low-temperature evaporation unit for treatment. This system includes a recirculation pump and multiple sets of recirculation pipes. The recirculation pump is fixed to the pipes via flanges. One end of each recirculation pipe is connected to the concentrate outlet of the membrane filtration unit, and the other end is connected to the inlet of the low-temperature evaporation unit. Flow meters and solenoid valves are installed on the recirculation pipes. The flow meters and solenoid valves are electrically connected to the control system, which automatically adjusts the concentrate recirculation flow rate based on feedback signals from the water quality monitoring device.

[0039] The entire system operates as follows: Grinding wastewater generated during semiconductor manufacturing first enters the collection tank through the inlet of wastewater collection unit 1. The wastewater flows naturally within the collection tank and is discharged through the outlet, then enters centrifugal separation unit 2 via a pipeline. The motor in centrifugal separation unit 2 drives a centrifuge to rotate at high speed. Under centrifugal force, the wastewater is separated into sludge and centrifugal liquid. The sludge is scraped off by a scraper device into a sludge collection hopper and periodically cleaned by a sludge collection box on a slide rail. The centrifugal liquid flows into a transfer tank through the outlet. A level sensor in the transfer tank monitors the liquid level in real time and transmits the signal to the control system. The control system adjusts the opening of the flow control valve based on the level signal to control the wastewater flow rate. Simultaneously, a stirring device drives a double-layered impeller via a geared motor to stir the wastewater, ensuring uniform mixing. The wastewater in the transfer tank enters the membrane filtration unit 4 through the outlet pipeline. In the membrane filtration unit 4, the wastewater undergoes deep filtration through a ceramic membrane module. The filtered clean water enters the recycled water tank through the outlet, while the concentrated water is returned to the low-temperature evaporation unit 5 through the concentrated water return system 8. Low-temperature evaporation unit 5 evaporates concentrated water using a low-temperature heat pump evaporator. The condensate from evaporation flows through pipes to bag filter unit 6 for further filtration. The filtered clean water enters the recycled water tank, while a small amount of sediment is periodically removed by a sludge removal device. A water quality monitoring device in the recycled water tank monitors water quality parameters in real time and transmits the data to the control system to ensure that the recycled water meets the production line's reuse requirements. Finally, the recycled water is discharged through a drain into the production workshop's water supply system for complete recycling.

[0040] The advantages of this invention are that, through the synergistic effect of each unit, it solves the problems of high operating costs, large footprint, and unstable effluent quality in traditional treatment technologies. The introduction of the centrifugal separator 2 significantly reduces the load on subsequent treatment units; the high-precision separation capability of the ceramic membrane filter 4 achieves deep removal of pollutants from the wastewater; and the low-temperature differential evaporation technology of the low-temperature evaporation device 6 reduces energy consumption and improves the system's operational stability. The stability of the reclaimed water quality is ensured through the water quality monitoring devices in the reclaimed water storage and reuse units. The entire system requires no chemical reagents, avoiding the introduction of additional salts. Combined with the desalination function of the low-temperature evaporation device 6, the reclaimed water quality meets the production line reuse standards. Seamless connection is achieved between the flow control devices and the concentrated water recirculation system of each unit, ensuring the continuity and stability of the wastewater treatment process. Through the above technical solutions, this invention achieves the goal of resource-based reuse and zero discharge of semiconductor grinding wastewater, which has significant theoretical and practical implications.

[0041] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A zero-discharge system for semiconductor grinding wastewater treatment, characterized in that: It includes: The wastewater collection unit is used to receive grinding wastewater generated during semiconductor manufacturing. It has an inclined bottom design and is equipped with a drain outlet. The centrifugal separation unit is connected to the wastewater collection unit via a pipeline, and is equipped with a centrifuge and a sludge collection hopper inside. The intermediate regulating unit is connected to the centrifugal separation unit via a pipeline and is equipped with a liquid level sensor and a stirring device inside. The membrane filtration unit is connected to the transfer and regulation unit via a pipe and contains multiple sets of ceramic membrane modules. The low-temperature evaporation unit is connected to the concentrate outlet of the membrane filtration unit via a pipe, and is equipped with a heat exchange tube bundle and a condensation device inside. The bag filter unit is connected to the condensate outlet of the low-temperature evaporation unit via a pipe, and contains multiple sets of filter bags. The recycled water storage unit is connected to the bag filter unit via a pipe and is equipped with a water quality monitoring device inside. The concentrate recirculation system is used to recirculate the concentrate from the membrane filtration unit back to the low-temperature evaporation unit.

2. The zero-discharge system for semiconductor grinding wastewater treatment according to claim 1, characterized in that: The inner wall of the wastewater collection tank is coated with a corrosion-resistant coating made of epoxy resin, and a sealing cover is provided on the top of the collection tank.

3. The zero-discharge system for semiconductor grinding wastewater treatment according to claim 1, characterized in that: The stirring device of the transfer regulating unit adopts a double-layer blade design, and the diameter of the upper blade is larger than that of the lower blade.

4. The zero-discharge system for semiconductor grinding wastewater treatment according to claim 1, characterized in that: The ceramic membrane module has a pore size ranging from 0.01 micrometers to 0.1 micrometers.

5. A zero-discharge system for semiconductor grinding wastewater treatment according to claim 4, characterized in that: The filter bag is made of polyester fiber material with a pore size of 1 micrometer and is fixed in the filter chamber by a snap fastener.

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