Fluorine-containing wastewater recovery treatment equipment and treatment process thereof

Abstract

The fluorine-containing wastewater recycling treatment equipment comprises a reclaimed water adjusting tank, the reclaimed water adjusting tank is communicated with a pretreatment system, a multi-medium filtering device, an activated carbon filter and a resin softening bed, the resin softening bed is communicated with an ultrafiltration system and a primary reverse osmosis system, a concentrated water reverse osmosis system is communicated with a recycling water tank, and the recycling water tank is communicated with a secondary reverse osmosis system. The concentrated water reverse osmosis system is communicated with the water inlet end of the primary reverse osmosis system and the HPRO system, the HPRO system is communicated with the fluorine, silicon and sulfuric acid removal system, and the fluorine, silicon and sulfuric acid removal system is communicated with the evaporative crystallization device and the sludge treatment system. According to the fluorine-containing wastewater recovery treatment equipment and the treatment process thereof, through combination of a modular process framework and switchable treatment units, a treatment path can be flexibly adjusted according to real-time water quality changes such as organic matter content and hardness of wastewater, the limitation of single flow of traditional equipment is broken through, and complex water quality scenes of industrial wastewater are comprehensively adapted; the multi-element requirements of deep purification, resource recovery and sludge reduction are met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of fluorine-containing wastewater recovery treatment, in particular to a fluorine-containing wastewater recovery treatment equipment and a treatment process thereof. BACKGROUND

[0002] With the development of industry, the discharge amount of production wastewater is increasing day by day. A large amount of fluorine-containing wastewater is generated in the industrial production process. The wastewater contains not only fluorine ions but also high hardness, high sulfate, silicon and suspended solids and other pollutants. If it is directly discharged, it will cause serious environmental pollution and waste a large amount of water resources. Therefore, it is of great significance to recover and treat the production wastewater to realize the recycling of water resources.

[0003] The existing fluorine-containing wastewater treatment equipment has the problems of single treatment process, incomplete pollutant removal, low water resource recovery rate, large sludge production and the like, and it is difficult to meet the needs of industrial wastewater deep treatment and recycling. In view of the above problems, the existing equipment needs to be improved. SUMMARY

[0004] The present application relates to the technical field of fluorine-containing wastewater recovery treatment, in particular to a fluorine-containing wastewater recovery treatment equipment and a treatment process thereof.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical scheme: a fluorine-containing wastewater recovery treatment equipment, comprising a reclaimed water adjusting tank,

[0006] The reclaimed water adjusting tank is used for receiving fluorine-containing wastewater and balancing water quality and quantity. The reclaimed water adjusting tank is in communication with a pretreatment system. The pretreatment system is in communication with a multi-medium filtration device. The multi-medium filtration device is internally filled with quartz sand and anthracite filter material layers. The multi-medium filtration device is connected with an activated carbon filter and a resin softening bed through a three-way pipe and a two-position three-way electromagnetic valve, respectively. The activated carbon filter is connected with the resin softening bed through a connecting pipe. The resin softening bed is in communication with an ultrafiltration system. The ultrafiltration system is in communication with a primary reverse osmosis system. The concentrated water outlet and the primary water outlet of the primary reverse osmosis system are in communication with a concentrated water reverse osmosis system and a reclaimed water pool, respectively. The water outlet and the concentrated water outlet of the concentrated water reverse osmosis system are in communication with a water inlet end of the primary reverse osmosis system and an HPRO system, respectively. The HPRO system is internally provided with a high-pressure reverse osmosis membrane assembly. The concentrated water outlet of the HPRO system is in communication with a defluorination, desilication and desulfurization system. The supernatant outlet and the sludge outlet of the defluorination, desilication and desulfurization system are in communication with an evaporation crystallization device and a sludge treatment system, respectively.

[0007] Preferably, the wastewater regulating tank is provided with a wastewater inlet pipe on one side, and a stirring device is arranged at the upper end of the wastewater regulating tank, and a lifting pump is arranged on the conveying pipe on the other side of the wastewater regulating tank.

[0008] Preferably, the pretreatment system comprises a chemical hardness removal unit, a sulfate removal unit, a fluorine removal unit, a silicon removal unit and a flocculation unit, and the chemical hardness removal unit and the flocculation unit are both provided with a dosing device, and the dosing device stores sodium carbonate, calcium chloride, magnesium oxide, sodium hydroxide and flocculating agents.

[0009] Preferably, the resin softening bed is internally filled with special ion exchange resin for adsorbing calcium and magnesium ions.

[0010] Preferably, the ultrafiltration system adopts an ultrafiltration membrane assembly with an average pore size between that of a reverse osmosis membrane and a microporous filter membrane.

[0011] Preferably, the fluorine and silicon removal system is provided with a sulfate removal agent and a fluorine and silicon removal agent dosing device.

[0012] Preferably, the evaporation crystallization device comprises a raw liquid tank, a feed pump, a non-condensable vapor preheater, a hot water preheater, an evaporation system, a vapor-liquid separator, a compressor system, a crystallization separator, a circulating pump, a discharge pump, a thickener and a centrifugal device, the evaporation system comprises a first-effect evaporator and a second-effect evaporator, and the compressor system is in communication with the steam outlet of the vapor-liquid separator and the shell side of the second-effect evaporator arranged in the evaporation system.

[0013] Preferably, the sludge treatment system comprises a sludge pump, a sludge tank and a plate-and-frame dewatering machine, and the sludge pump is connected with the sludge outlet of the fluorine and silicon removal system and the sludge tank, and the sludge tank is connected with the plate-and-frame dewatering machine.

[0014] A fluorine-containing wastewater recycling treatment process, characterized in that it comprises the following steps:

[0015] S1, the wastewater enters the wastewater regulating tank through the wastewater inlet pipe, is stirred and mixed by the stirring device in the tank, the water quality and quantity are balanced, and the pretreatment system is entered;

[0016] S2, the pretreatment system: this stage contains chemical hardness removal, sulfate removal, fluorine removal, silicon removal and other processes, adopts a chemical softening method to remove hardness, adds sodium carbonate, calcium chloride, magnesium oxide and sodium hydroxide and other reagents through the dosing device, and reacts to form calcium carbonate and magnesium hydroxide precipitates to remove calcium and magnesium; then, a flocculating agent is added to form large alum flower rolls to remove suspended particles, and synchronous hardness removal and suspended solids removal are realized, which can reduce the hardness by 90%, and the pretreatment system effluent enters the subsequent system;

[0017] S3, multi-medium filter device: the filter material layer of quartz sand, anthracite and the like in the device is used to intercept suspended impurities in water, the filtering function is mainly to remove suspended or colloidal impurities in water, especially to effectively remove suspended flocculation and the like which cannot be removed by sedimentation technology, under normal working conditions, the multi-medium filter effluent directly enters the resin softening bed, if the organic matter content in water is relatively high, the multi-medium filter effluent pipe is switched to enter the activated carbon filter;

[0018] S4, activated carbon filter: mainly using activated carbon organic flocculation with high carbon content, large molecular weight and large specific surface area to physically adsorb impurities in water, so as to meet the water quality requirement, when water flows through the pores of activated carbon, various suspended particles, organic matter and the like are adsorbed in the pores of activated carbon under the action of van der waals force, so as to effectively remove organic matter and meet the water inlet requirement of RO membrane on organic matter;

[0019] S5, resin softening bed: using ion exchange technology, through special resin, adsorption and ion exchange of calcium, magnesium and other multivalent ions are realized, and hardness in wastewater is deeply removed, resin softening effluent enters the ultrafiltration system;

[0020] S6, ultrafiltration system: the average pore size of the system is between the reverse osmosis membrane and the microporous filter membrane, bacteria, viruses, colloids, macromolecules and the like in water are intercepted, while water and low molecular weight solutes are permeated through the membrane, the pollution degree of the reverse osmosis membrane is greatly reduced, and the ultrafiltration effluent enters the primary reverse osmosis system;

[0021] S7, primary reverse osmosis system: the core of the reverse osmosis system is the reverse osmosis membrane, which is a pressure-driven membrane separation system, water molecules can permeate the reverse osmosis membrane under the action of pressure, salt ions cannot permeate the reverse osmosis membrane and are enriched and concentrated on the concentrated water side, the primary reverse osmosis is designed with a recovery rate of 70%, the primary effluent enters the reuse water tank, and the concentrated water enters the concentrated water reverse osmosis system;

[0022] S8, concentrated water reverse osmosis system: the primary reverse osmosis concentrated water is sent to the concentrated water reverse osmosis system, the concentrated water reverse osmosis is designed with a recovery rate of 60%, the system effluent returns to the primary reverse osmosis water inlet, and the concentrated water enters the HPRO system;

[0023] S9, HPRO system: the membrane concentration system adopts HPRO process to realize ion concentration, the HPRO membrane (high pressure reverse osmosis membrane) is a form of reverse osmosis, which is resistant to pollution, high pressure and TDS, anti-pollution and anti-fouling, the membrane assembly is easy to clean, can be replaced alone, and the HPRO effluent enters the concentrated water RO front end, and the HPRO concentrated water enters the defluorination, desilication and sulfuric acid removal system;

[0024] S10, defluorination, desilication and sulfuric acid removal system: including sulfate removal, chemical defluorination and desilication, wherein, the chemical defluorination and desilication process synchronously adds sulfate removal, defluorination and desilication reagents, sulfate, fluoride ions and silicon dioxide respectively react with the reagents to form complex salts, and are removed by flocculation and precipitation;

[0025] S11, the precipitated sludge is pumped into a sludge tank by a sludge pump, and the supernatant enters an evaporation crystallization device;

[0026] S12, the evaporation crystallization device: the evaporation crystallization system adopts an MVR forced circulation evaporator, the solution is sent to a non-condensing steam preheater and a hot water preheater in sequence by a feed pump after coming out from a raw liquid tank, the material temperature is gradually increased from 20 DEG C to 25 DEG C to 85 DEG C, and then the material is sent to an evaporation system for concentration, the supersaturated concentrated solution is sent into a separator for vapor-liquid separation, the gas produced after flashing is sent into a compressor system, small particles of crystals are precipitated in the concentrated solution due to evaporation of part of water, the precipitated crystals fall in the crystallization separator and continuously grow, part of the concentrated solution is pumped back to the forced circulation evaporator for circulation concentration, when the concentration ratio reaches the requirement, part of the concentrated solution is sent to a thickener and a centrifugal device by a discharge pump, the crystals are bagged after centrifugal dewatering and are sent out of the evaporation system, the mother liquor after centrifugation is returned to the evaporator or a part of the mother liquor is accumulated and discharged to a drum drying treatment system, when the preheated material enters the evaporator, the material exchanges heat with secondary steam which is raised to 103 DEG C by compression for evaporation, the whole system reaches thermal equilibrium, and only the motor of the compressor is needed to maintain the thermal equilibrium of the MVR system evaporation except for part of fresh steam needed for preheating;

[0027] S13, the secondary steam coming out from the top of the separator enters the MVR compression system, the temperature of the secondary steam can be increased to about 103 DEG C after compression, the compressed steam enters the shell side of the first effect evaporator and the second effect evaporator as a heat source, the steam after heating the material is condensed into 100 DEG C distilled water and flows to a distilled water tank and is pumped out of the boundary area by a pump;

[0028] S14, sludge treatment system: the sludge generated by the wastewater treatment system enters the sludge treatment system, is pressed and dewatered by a dewatering machine, and is subjected to sludge reduction treatment, and sludge with a water content of about 60% is generated and is transported out for disposal.

[0029] Compared with the prior art, the fluorine-containing wastewater recycling treatment equipment and the treatment process have the beneficial effects that,

[0030] (1) by matching the middle water adjusting tank with the composite pretreatment system, the wastewater quality and quantity are balanced first, then the pollutants such as hardness, fluoride ions and sulfate ions are simultaneously and efficiently removed through multi-agent synergistic reaction and flocculation and sedimentation, the single hardening removal rate reaches 90%, and the problems of poor adaptability to water quality fluctuation and incomplete removal of pollutants of traditional equipment are solved;

[0031] (2) Through the combination of multi-medium filter device, activated carbon filter and resin softening bed, suspended flocculation, adsorption of organic matter and deep removal of calcium and magnesium ions are intercepted step by step, forming a "three-stage pretreatment barrier", which can accurately control the water quality in the RO membrane tolerance range, greatly reduce the membrane pollution risk, and provide stable and high-quality water for the subsequent membrane separation process;

[0032] (3) Through the connection of the ultrafiltration system, the first reverse osmosis system, the concentrated water reverse osmosis system and the HPRO system, the ultrafiltration membrane is used to intercept macromolecular impurities to protect the reverse osmosis membrane, and then the three-stage membrane separation ladder is used for concentration recovery, the recovery rate of the first RO is 70%, the recovery rate of the concentrated water RO is 60%, the recovery efficiency is increased by more than 30% compared with the traditional single membrane system, and the water resources are maximized;

[0033] (4) Through the combination of the fluoride removal, silicon removal and sulfuric acid removal system and the MVR forced circulation evaporation crystallization device, the easy scaling pollutants in the concentrated water are removed, and then the evaporation crystallization process of gradient preheating and steam circulation is used to realize the resource recovery of crystal and the reuse of distilled water, avoid the scaling and blockage of the evaporator, and achieve the double goals of end concentrated water zero discharge and resource recovery;

[0034] (5) Through the combination of the modular process architecture and the switchable treatment unit (multi-medium / activated carbon filter), the treatment path can be flexibly adjusted according to the real-time water quality changes such as organic matter content and hardness of the wastewater, the limitation of the single traditional equipment process is broken, the complex water quality scene of industrial wastewater is fully adapted, and the multiple needs of deep purification, resource recovery and sludge reduction are met. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 It is a front view structural schematic diagram of the whole invention;

[0036] Figure 2 It is a front view structural schematic diagram of the water regulating tank in the invention;

[0037] Figure 3 It is a front view structural schematic diagram of the pretreatment system and the multi-medium filter device in the invention;

[0038] Figure 4 It is a front view structural schematic diagram of the multi-medium filter device, the activated carbon filter and the resin softening bed in the invention;

[0039] Figure 5 It is a working process schematic diagram of the evaporation crystallization device in the invention;

[0040] Figure 6 It is a treatment process schematic diagram of the invention.

[0041] In the figure: 1, water conditioning tank; 101, wastewater inlet pipe; 102, stirring device; 103, conveying pipe; 104, lifting pump; 2, pretreatment system; 201, dosing device; 3, multi-medium filter device; 301, three-way pipe; 302, two-position three-way electromagnetic valve; 4, activated carbon filter; 401, connecting pipe; 5, resin softening bed; 6, ultrafiltration system; 7, primary reverse osmosis system; 8, concentrated water reverse osmosis system; 9, reclaimed water tank; 10, HPRO system; 11, fluoride removal, silicon removal and sulfuric acid removal system; 12, evaporation crystallization device; 13, sludge treatment system. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative labor fall within the scope of protection of the present application.

[0043] Please refer to Figures 1-6 , the present application provides a technical solution: a fluorine-containing wastewater recycling treatment equipment and its treatment process, according to Figure 1 , Figure 2 , Figure 3 and Figure 6 shown, the water conditioning tank 1 is used for receiving fluorine-containing wastewater and balancing water quality and quantity, and the water conditioning tank 1 is communicated with the pretreatment system 2, one side of the water conditioning tank 1 is provided with a wastewater inlet pipe 101, and a stirring device 102 is arranged at the upper end of the water conditioning tank 1, and a lifting pump 104 is arranged on the conveying pipe 103 arranged on the other side of the water conditioning tank 1, the pretreatment system 2 includes a chemical hardness removal unit, a sulfate removal unit, a fluoride removal unit, a silicon removal unit and a flocculation unit, and the chemical hardness removal unit and the flocculation unit are both provided with a dosing device 201, and the dosing device 201 stores sodium carbonate, calcium chloride, magnesium oxide, sodium hydroxide and flocculating agent inside.

[0044] According to Figure 1 , Figure 3 , Figure 4 and Figure 6As shown, the pretreatment system 2 is in communication with the multi-medium filtering device 3, which is internally filled with quartz sand and anthracite filter material layer, and the multi-medium filtering device 3 is connected with the activated carbon filter 4 and the resin softening bed 5 through the three-way pipe 301 and the two-position three-way electromagnetic valve 302, respectively, while the activated carbon filter 4 is connected with the resin softening bed 5 through the connecting pipe 401, the resin softening bed 5 is internally filled with special ion exchange resin for adsorbing calcium and magnesium ions, the resin softening bed 5 is in communication with the ultrafiltration system 6, and the ultrafiltration system 6 is in communication with the primary reverse osmosis system 7, the ultrafiltration system 6 adopts an ultrafiltration membrane assembly with an average pore size between the reverse osmosis membrane and the microporous filter membrane, while the concentrated water outlet and the primary water outlet of the primary reverse osmosis system 7 are in communication with the concentrated water reverse osmosis system 8 and the reuse water tank 9, respectively, the concentrated water outlet and the concentrated water inlet of the concentrated water reverse osmosis system 8 are in communication with the primary reverse osmosis system 7 and the HPRO system 10, respectively, the HPRO system 10 is internally provided with a high-pressure reverse osmosis membrane assembly, and the concentrated water outlet of the HPRO system 10 is in communication with the fluoride-removing, silicon-removing and sulfate-removing system 11, which is provided with a sulfate-removing agent and a fluoride-removing and silicon-removing agent adding device.

[0045] According to Figure 1 , Figure 5 and Figure 6 , the supernatant outlet and the sludge outlet of the fluoride-removing, silicon-removing and sulfate-removing system 11 are in communication with the evaporation crystallization device 12 and the sludge treatment system 13, respectively, the evaporation crystallization device 12 comprises a raw liquid tank, a feed pump, a non-condensing steam preheater, a hot water preheater, an evaporation system, a vapor-liquid separator, a compressor system, a crystallization separator, a circulating pump, a discharge pump, a thickener and a centrifugal device, and the evaporation system comprises a first-effect evaporator and a second-effect evaporator, while the compressor system is in communication with the steam outlet of the vapor-liquid separator and the shell side of the second-effect evaporator arranged in the evaporation system, the sludge treatment system 13 comprises a sludge pump, a sludge tank and a plate-and-frame type dehydrator, and the two ends of the sludge pump are connected with the sludge outlet of the fluoride-removing, silicon-removing and sulfate-removing system 11 and the sludge tank, respectively, while the sludge tank is connected with the plate-and-frame type dehydrator.

[0046] A fluorine-containing wastewater recycling treatment process, characterized by comprising the following steps:

[0047] S1, the wastewater enters the reclaimed water adjusting tank 1 through the wastewater inlet pipe 101, is stirred and mixed by the stirring device 102 in the tank, the water quality and quantity are balanced, and the pretreatment system 2 is entered;

[0048] S2, pretreatment system 2: this stage contains chemical hardness removal, sulfate removal, fluorine removal, silicon removal and other processes, using chemical softening method to remove hardness, through the dosing device 201 to add sodium carbonate, calcium chloride, magnesium oxide and sodium hydroxide and other reagents, reaction to form calcium carbonate, magnesium hydroxide precipitate to remove calcium and magnesium; then add flocculating agent to form large alunite roll to remove suspended particles, realize synchronous hardness removal and suspended solids removal, can reduce 90% of the hardness, the pretreatment system 2 effluent enters the subsequent system;

[0049] S3, multi-medium filter device 3: quartz sand, anthracite and other filter material layer in the device are used to intercept suspended impurities in water, the main function of filtration is to remove suspended or colloidal impurities in water, especially to effectively remove suspended floc which cannot be removed by sedimentation technology, under normal working conditions, the multi-medium filter effluent directly enters the resin softening bed 5, if the organic matter content in the water is high, the multi-medium filter effluent pipe switches into the activated carbon filter 4;

[0050] S4, activated carbon filter 4: mainly uses activated carbon organic flocculation body with high carbon content, large molecular weight and large specific surface area to physically adsorb impurities in water, so as to meet the water quality requirements, when the water flow passes through the pores of activated carbon, various suspended particles and organic matter are adsorbed in the pores of activated carbon under the action of van der waals force, so as to effectively remove organic matter and meet the water inlet requirement of RO membrane for organic matter;

[0051] S5, resin softening bed 5: using ion exchange technology, through special resin, the adsorption and ion exchange of calcium, magnesium and other multivalent ions are realized, and the hardness in wastewater is deeply removed, the resin softening effluent enters the ultrafiltration system 6;

[0052] S6, ultrafiltration system 6: the average pore size of this system is between the reverse osmosis membrane and the microporous filter membrane, which can intercept bacteria, viruses, colloids, macromolecules and other particles in water, while water and low molecular weight solutes can pass through the membrane, greatly reducing the pollution degree of reverse osmosis membrane, the ultrafiltration effluent enters the primary reverse osmosis system 7;

[0053] S7, primary reverse osmosis system 7: the core of reverse osmosis system is reverse osmosis membrane, which is a pressure driven membrane separation system, water molecules can pass through the reverse osmosis membrane under the action of pressure, while salt ions cannot pass through the reverse osmosis membrane and are concentrated on the concentrated water side, the primary reverse osmosis is designed with a recovery rate of 70%, the primary effluent enters the reuse water tank 9, and the concentrated water enters the concentrated water reverse osmosis system 8;

[0054] S8, concentrated water reverse osmosis system 8: the concentrated water of the primary reverse osmosis is sent to the concentrated water reverse osmosis system 8, which is designed with a recovery rate of 60%, the system effluent returns to the primary reverse osmosis inlet 7, and the concentrated water enters the HPRO system 10;

[0055] S9, HPRO system 10: the membrane concentration system adopts the HPRO process to realize ion concentration, the HPRO membrane (high pressure reverse osmosis membrane) is a form of reverse osmosis, resistant to pollution, high pressure and TDS, anti-pollution and anti-fouling, the membrane module is easy to clean, can be replaced alone, HPRO generates into the concentrated water RO front end, and the HPRO concentrated water enters the fluoride and silicon removal and sulfuric acid system 11;

[0056] S10, fluoride and silicon removal and sulfuric acid system 11: including sulfate removal, chemical fluoride and silicon removal, wherein, the chemical fluoride and silicon removal process synchronously adds sulfate removal, fluoride and silicon removal reagent, sulfate, fluoride and silicon dioxide respectively react with the reagent to form a complex salt, which is removed by flocculation and precipitation;

[0057] S11, the sludge is pumped into the sludge pool by the sludge pump, and the supernatant enters the evaporation crystallization device 12;

[0058] S12, evaporation crystallization device 12: the evaporation crystallization system adopts MVR forced circulation evaporator, the solution is sent to the non-condensing steam preheater and hot water preheater by the feed pump, and the material temperature is gradually increased from 20℃ to 25℃ to 85℃, and then sent to the evaporation system for concentration. The supersaturated concentrated solution is separated into a gas-liquid separator, and the gas produced after flashing is compressed into a compressor system. Because part of the water is evaporated, small particles of crystals are precipitated in the concentrated solution. The precipitated crystals fall in the crystallization separator and continue to grow. Part of the concentrated solution is pumped back to the forced circulation evaporator for circulation concentration. When the concentration ratio reaches the required value, part of the concentrated solution is sent to the thickener and centrifugal device by the discharge pump. After centrifugal dewatering, the crystals are bagged and sent out of the evaporation system. The mother liquor after centrifugation returns to the evaporator or a part of the mother liquor is accumulated and discharged to the drum drying treatment system. When the preheated material enters the evaporator, it exchanges heat with the secondary steam raised to 103℃ for evaporation. The whole system reaches thermal equilibrium. Except for the fresh steam required for preheating, only the motor of the compressor is needed to maintain the thermal balance of the MVR system evaporation;

[0059] S13, the secondary steam from the top of the separator enters the MVR compression system. After being compressed, the temperature of the secondary steam can be increased to about 103℃. The compressed steam enters the shell side of the first and second evaporators as a heat source. The steam after heating the material condenses into 100℃ distilled water and flows to the distilled water tank for pumping out of the boundary area;

[0060] S14, sludge treatment system 13: the sludge generated by the wastewater treatment system enters the sludge treatment system 13, which is dehydrated by a dehydrator to reduce the amount of sludge, and produces sludge with a water content of about 60%, which is transported for disposal.

[0061] The terms "central", "longitudinal", "transverse", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate orientations or positional relationships based on the orientations or positional relationships as shown in the drawings, are made only for the purpose of facilitating the description of the present application and simply intended to facilitate description of the application, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the protection scope of the present application.

[0062] Although the present application has been described in detail with reference to the foregoing embodiments, the technical solutions recorded in the foregoing embodiments can be modified or some technical features can be replaced by equivalent features by those skilled in the art, and any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A fluoride-containing wastewater recovery and treatment device, comprising a greywater equalization tank (1), characterized in that: The greywater equalization tank (1) is used to receive fluoride-containing wastewater and balance its quality and quantity. The greywater equalization tank (1) is connected to the pretreatment system (2), and the pretreatment system (2) is connected to the multi-media filter device (3). The multi-media filter device (3) is filled with a layer of quartz sand and anthracite filter media. The multi-media filter device (3) is connected to the activated carbon filter (4) and the resin softening bed (5) through a three-way pipe (301) and a two-position three-way solenoid valve (302), respectively. The activated carbon filter (4) is connected to the resin softening bed (5) through a connecting pipe (401). The resin softening bed (5) is connected to the ultrafiltration system (6), and the ultrafiltration system (6) is connected to a... The first-stage reverse osmosis system (7) is connected, and the concentrate outlet and the first-stage product water outlet of the first-stage reverse osmosis system (7) are connected to the concentrate reverse osmosis system (8) and the recycled water tank (9), respectively. The product water outlet and the concentrate outlet of the concentrate reverse osmosis system (8) are connected to the inlet of the first-stage reverse osmosis system (7) and the HPRO system (10), respectively. The HPRO system (10) is equipped with a high-pressure reverse osmosis membrane module, and the concentrate outlet of the HPRO system (10) is connected to the defluorination, desiliconization and sulfuric acid removal system (11). At the same time, the supernatant outlet and the sludge outlet of the defluorination, desiliconization and sulfuric acid removal system (11) are connected to the evaporation crystallization device (12) and the sludge treatment system (13), respectively.

2. The fluoride-containing wastewater recovery and treatment equipment as described in claim 1, characterized in that: The wastewater inlet pipe (101) is provided on one side of the greywater regulating tank (1), and a stirring device (102) is provided in the middle of the upper end of the greywater regulating tank (1). At the same time, a booster pump (104) is provided on the conveying pipe (103) on the other side of the greywater regulating tank (1).

3. The fluoride-containing wastewater recovery and treatment equipment as described in claim 1, characterized in that: The pretreatment system (2) includes a chemical hardening unit, a sulfate removal unit, a fluoride removal unit, a silicon removal unit, and a flocculation unit. Both the chemical hardening unit and the flocculation unit are equipped with a dosing device (201). The dosing device (201) contains sodium carbonate, calcium chloride, magnesium oxide, sodium hydroxide, and flocculants.

4. The fluoride-containing wastewater recovery and treatment equipment as described in claim 1, characterized in that: The resin softening bed (5) is filled with a special ion exchange resin for adsorbing calcium and magnesium ions.

5. The fluoride-containing wastewater recovery and treatment equipment as described in claim 1, characterized in that: The ultrafiltration system (6) uses an ultrafiltration membrane module with an average pore size between that of a reverse osmosis membrane and a microporous membrane.

6. The fluoride-containing wastewater recovery and treatment equipment as described in claim 1, characterized in that: The defluorination, desiliconization and sulfuric acid removal system (11) is equipped with a sulfate removal agent and a defluorination and desiliconization agent dosing device.

7. The fluoride-containing wastewater recovery and treatment equipment as described in claim 1, characterized in that: The evaporation crystallization device (12) includes a raw liquid tank, a feed pump, a non-condensable steam preheater, a hot water preheater, an evaporation system, a vapor-liquid separator, a compressor system, a crystallization separator, a circulation pump, a discharge pump, a thickener, and a centrifuge. The evaporation system includes a first-effect evaporator and a second-effect evaporator. The compressor system is connected to the steam outlet of the vapor-liquid separator and the shell side of the second-effect evaporator in the evaporation system.

8. The fluoride-containing wastewater recovery and treatment equipment as described in claim 1, characterized in that: The sludge treatment system (13) includes a sludge pump, a sludge tank and a plate and frame dewatering machine. The two ends of the sludge pump are connected to the sludge outlet of the defluorination, desiliconization and sulfuric acid removal system (11) and the sludge tank, respectively. At the same time, the sludge tank is connected to the plate and frame dewatering machine.

9. A process for recovering and treating fluoride-containing wastewater, characterized in that, Includes the following steps: S1. Wastewater enters the greywater regulating tank (1) through the wastewater inlet pipe (101). In the tank, it is stirred and mixed by the stirring device (102) to balance the water quality and quantity, and then enters the pretreatment system (2). S2, Pretreatment System (2): This stage includes chemical hardening, sulfate removal, fluoride removal, and silicon removal processes. Chemical softening is used to remove hardening. Sodium carbonate, calcium chloride, magnesium oxide, and sodium hydroxide are added through the dosing device (201) to react and form calcium carbonate and magnesium hydroxide precipitates for calcium and magnesium removal. Then, flocculants are added to form large flocs to remove suspended particles, achieving simultaneous hardening and suspended solids removal. This can reduce hardness by 90%. The effluent from the pretreatment system (2) enters the subsequent system. S3, Multi-media filtration device (3): The device uses filter media such as quartz sand and anthracite to intercept suspended impurities in the water. The main function of filtration is to remove suspended or colloidal impurities in the water, especially to effectively remove suspended flocs that cannot be removed by sedimentation technology. Under normal working conditions, the water from the multi-media filter directly enters the resin softening bed (5). If the organic matter content in the water is high, the water outlet pipe of the multi-media filter is switched to the activated carbon filter (4). S4, Activated Carbon Filter (4): It mainly uses activated carbon organic flocs with high carbon content, large molecular weight and large specific surface area to physically adsorb impurities in water to meet water quality requirements. When water flows through the pores of activated carbon, various suspended particles and organic matter are adsorbed in the pores of activated carbon under the action of van der Waals forces, thereby effectively removing organic matter and meeting the RO membrane's requirements for organic matter in the water. S5, Resin Softening Bed (5): Using ion exchange technology, special resin is used to achieve the adsorption and ion exchange of multivalent ions such as calcium and magnesium, and to deeply remove the hardness in wastewater. The resin-softened water enters the ultrafiltration system (6). S6, Ultrafiltration System (6): The average pore size of this system is between that of the reverse osmosis membrane and the microporous filter membrane. It intercepts bacteria, viruses, colloids, macromolecules and other particles in the water, while water and low molecular weight solutes permeate through the membrane, greatly reducing the fouling degree of the reverse osmosis membrane. The ultrafiltration water enters the first-stage reverse osmosis system (7). S7, First-stage reverse osmosis system (7): The core of the reverse osmosis system is the reverse osmosis membrane, which is a pressure-driven membrane separation system. Water molecules can pass through the reverse osmosis membrane under pressure, while salt ions cannot pass through the reverse osmosis membrane and are enriched and concentrated on the concentrate side. The first-stage reverse osmosis is designed to have a recovery rate of 70%. The first-stage product water enters the reclaimed water tank (9), and the concentrate enters the concentrate reverse osmosis system (8). S8, Concentrate Reverse Osmosis System (8): The first-stage reverse osmosis concentrate is sent into the concentrate reverse osmosis system (8). The concentrate reverse osmosis is designed to have a recovery rate of 60%. The system's product water is returned to the first-stage reverse osmosis feed water (7), and the concentrate enters the HPRO system (10). S9, HPRO system (10): The membrane concentration system adopts HPRO process to achieve ion concentration. HPRO membrane (high pressure reverse osmosis membrane) is a form of reverse osmosis. It is resistant to fouling, high pressure, and TDS. It is also resistant to fouling and scaling. The membrane module is easy to clean and can be replaced individually. HPRO generates water that enters the RO front end. HPRO concentrated water enters the defluorination, desiliconization and sulfuric acid removal system (11). S10, Fluorine, Silicon and Sulfuric Acid Removal System (11): Includes sulfate removal, chemical fluorine and silicon removal, wherein the chemical fluorine and silicon removal process simultaneously adds sulfate removal and fluorine and silicon removal agents, sulfate, fluoride ions and silicon dioxide react with the agents to form complex salts, which are removed by flocculation and precipitation; S11. The settled sludge is pumped into the sludge tank by the sludge pump, and the supernatant enters the evaporation crystallization device (12). S12, Evaporation Crystallization Unit (12): The evaporation crystallization system adopts an MVR forced circulation evaporation crystallizer. The solution comes out of the raw liquid tank and is successively transported by the feed pump to the non-condensable steam preheater and the hot water preheater. The material temperature gradually changes from 20℃→25℃→85℃ before being transported to the evaporation system for concentration. The supersaturated concentrate then enters the separator for vapor-liquid separation. The gas generated after flash evaporation enters the compressor system. Because some water is evaporated, small crystals will precipitate in the concentrate. The precipitated crystals fall in the crystallization separator and continue to grow. Part of the concentrate is then processed by the separator. The pump returns to the forced circulation evaporator for circulation concentration. When the concentration ratio reaches the required level, a portion of the concentrated liquid is sent to the thickener and centrifuge by the discharge pump. After centrifugation and dehydration, the crystals are bagged and sent out of the evaporation system. The mother liquor after centrifugation is returned to the evaporator or a portion of the accumulated mother liquor is discharged to the drum drying system. When the preheated material enters the evaporator, it undergoes heat exchange and evaporation with the secondary steam that has been compressed to 103°C. The entire system reaches thermal equilibrium. Apart from the need for some fresh steam for preheating, only the compressor motor is needed to maintain the thermal equilibrium of the MVR system evaporation. S13. The secondary steam coming out from the top of the separator enters the MVR compression system. After being compressed, the temperature of the secondary steam can be raised to about 103°C. The compressed steam enters the shell side of the first-effect evaporator and the second-effect evaporator as a heat source. The steam heated by the material is condensed into 100°C distilled water and flows to the distilled water tank, which is then pumped out of the boundary area. S14, Sludge Treatment System (13): The sludge generated by the wastewater treatment system enters the sludge treatment system (13), is dewatered by a dewatering machine, and undergoes sludge reduction treatment to produce sludge with a moisture content of about 60%, which is then transported off-site for disposal.

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