Incinerator washing tower wastewater and etching bath liquid reclaimed water recycling device and method

Abstract

The invention discloses an incinerator washing tower wastewater and etching bath solution reclaimed water recycling device and method, and the method comprises the following steps: mixing an etching bath solution with incinerator washing tower wastewater in a comprehensive adjusting tank after the etching bath solution passes through a defluorination reactor; effluent sequentially enters the second-stage physicochemical treatment system, the membrane bioreactor, the first-stage reverse osmosis device, the second-stage reverse osmosis device, the third-stage reverse osmosis device and the MVR evaporation device, and produced water of the first-stage reverse osmosis device, the second-stage reverse osmosis device and the high-pressure reverse osmosis device and evaporation condensate water of the MVR evaporation device all flow into a recycling water tank. Incinerator washing tower waste water and etching tank liquid in the integrated circuit board industry are collected in a classified mode, the etching tank liquid waste water is mixed with the incinerator washing tower waste water after being defluorinated through the defluorination reactor, the mixture enters the second-stage physicochemical treatment system, the MBR and the third-stage reverse osmosis system to be treated, waste water treatment is efficient, the reuse rate of reclaimed water is high, and the recycling effect is good. And the recycling rate reaches 98% or above.

Description

Technical Field

[0001] The invention relates to the technical field of wastewater treatment, and in particular to a device and method for recycling wastewater from a washing tower of an integrated circuit board incinerator and water from an etching tank liquid. Background Art

[0002] In recent years, with the rapid growth of demand from downstream industries including communications, industrial control, and consumer electronics, the overall demand for integrated circuits has continued to increase. However, the production process of integrated circuits will produce etching tank liquid and incinerator washing wastewater, both of which are wastewater with extremely low organic concentrations but extremely high fluoride concentrations. Effectively removing fluorides and protecting subsequent equipment, pipelines, and membrane components are difficult problems in wastewater treatment. At the same time, if fluorides and SS are effectively removed, the wastewater can be reused and water resources can be saved.

[0003] At present, wastewater treatment technologies in the integrated circuit industry mainly include physical and chemical technology, electrochemical technology and biological technology.

[0004] Physical and chemical technology is a technology that uses physical and chemical principles to treat wastewater. Common physical and chemical technologies include precipitation, adsorption and ion exchange. The precipitation method precipitates pollutants in the wastewater by adding chemical agents, thereby achieving the purpose of purification; the adsorption method uses adsorbents to adsorb pollutants in the wastewater on the surface, thereby achieving the purpose of purification; the ion exchange method uses ion exchange resins to exchange ions in the wastewater with ions on the resin, thereby achieving the purpose of purification. Physical and chemical technology has the advantages of good treatment effect and simple operation, but there are also some problems, such as low treatment efficiency and the generation of a large amount of sludge.

[0005] Electrochemical technology is a technology that uses electrochemical principles to treat wastewater. Among them, electrosorption technology is a commonly used electrochemical technology. Through the action of voltage, organic matter in wastewater can be adsorbed onto electrodes, thereby achieving wastewater purification. Electrochemical technology has the advantages of high efficiency and strong controllability, but there are still some problems in practical applications. Among them, the selection of electrode materials is a key issue. Different electrode materials have different effects on the adsorption of organic matter in wastewater. How to select suitable electrodes according to the type of wastewater is an important topic to be studied.

[0006] Biotechnology is a technology that uses organisms or their metabolites to treat wastewater. Commonly used biotechnologies include aerobic biological methods, anaerobic biological methods, and microbial fuel cells. Aerobic biological methods use the metabolic capacity of microorganisms to oxidize and degrade organic matter into harmless substances. Anaerobic biological methods use anaerobic microorganisms to degrade organic matter under anaerobic conditions. Microbial fuel cells use the electricity generated by the metabolism of microorganisms to achieve the purpose of wastewater treatment. Biotechnology has the advantages of low resource consumption and low operating costs in wastewater treatment, but it also faces some challenges. Among them, microbial culture conditions are a key problem. Different microorganisms have different requirements for environmental conditions. Therefore, the culture conditions need to be precisely controlled to improve the activity and degradation efficiency of microorganisms. In addition, the stability of the organism is also an important problem. It is necessary to maintain the activity and stability of the microorganism under long-term operation.

[0007] In summary, the wastewater treatment technology in the integrated circuit industry has made great progress, but it still faces some challenges. It is necessary to seek a combination of methods and devices that comprehensively utilize multiple technologies to form an efficient, low-cost, and environmentally friendly wastewater treatment system. At the same time, it is necessary to focus on the problem of large amounts of fluoride in wastewater, and realize the reuse of reclaimed water, provide sustainable development of wastewater treatment technology, and bring benefits to enterprises. Summary of the invention

[0008] In view of the deficiencies in the prior art, the present invention provides a device and method for recycling wastewater from an incinerator scrubber and water from an etching tank. The wastewater from an incinerator scrubber and the etching tank liquid in the integrated circuit board industry are classified and collected, and the etching tank liquid wastewater is defluorinated in a defluorination reactor and then mixed with the wastewater from the incinerator scrubber. The wastewater is sequentially treated in a secondary physicochemical treatment system, an MBR membrane bioreactor and a tertiary reverse osmosis system. The wastewater is efficiently treated and the utilization rate of the reclaimed water is high.

[0009] In order to solve the above technical problems, the first aspect of the present invention provides a method for recycling wastewater from an incinerator scrubber and water from an etching tank, comprising the following steps:

[0010] S1, the etching tank liquid is mixed with the wastewater from the incinerator washing tower in a comprehensive regulating tank after passing through the defluorination reactor;

[0011] The defluorination reactor adopts high-density sludge reflux method (HDS) to remove fluorine, and the mass concentration of sludge is 15%-20%. The increase of sludge particles increases the collision probability between particles, which not only enhances the precipitation effect and makes the effluent clearer, but also has a high sludge concentration, reducing the load of the filter press; more importantly, through the crystallization method, the moisture content between sludge particles is reduced, the sludge particles are dense, and the dehydration performance is good. The moisture content can be as low as 40%, which is much higher than the 65% to 70% moisture content of the traditional flocculation method;

[0012] Sulfuric acid and slaked lime are added to the defluorination reactor to adjust the pH to 5-9; 3-10 mg / L of PAM (polyacrylamide) and 300-500 mg / L of PAC (polyaluminium chloride) are also added to the defluorination reactor; the defluorination reactor is combined with PAC for defluorination, and the F / Al molar ratio equal to 3 is the dividing point between adsorption and co-precipitation. When the F / Al molar ratio is less than 3, it is mainly adsorbed on the surface of aluminium hydroxide. When the F / Al molar ratio is greater than 3, F and Al form amorphous substances and are adsorbed together. When the PAC dosage exceeds 700 mg / L, the pH drops due to the hydrolysis of PAC and exceeds the flocculation condition, resulting in the inability to form flocculated particles, thereby losing the precipitation effect;

[0013] S2. The effluent from the comprehensive regulating pool enters the secondary physical and chemical treatment system, which specifically includes:

[0014] S21, the effluent from the comprehensive regulating tank enters the reaction precipitation integrated machine, and calcium chloride, slaked lime, PAC and PAM are added to further remove fluoride;

[0015] S22, the supernatant of the effluent from the reaction-precipitation integrated machine flows into the flotation tank by gravity, and alkali solution, PAC and PAM are added to remove suspended particles in the wastewater and reduce the concentration of SS (suspended matter);

[0016] S3, the effluent from the flotation tank flows into the MBR membrane bioreactor by gravity, and the soluble organic matter and colloidal substances in the wastewater are removed through interception and filtration of the hollow fiber membrane and biodegradation of microorganisms under aerobic conditions, and SS is further removed to <50 mg / L, and the particle size of the effluent particles is below 0.5 μm;

[0017] S4, the effluent from the membrane bioreactor (MBR) enters a three-stage reverse osmosis system, wherein the three-stage reverse osmosis system comprises a primary reverse osmosis device, a secondary reverse osmosis device, a tertiary reverse osmosis device and an MVR (mechanical vapor recompression) evaporation device connected in sequence;

[0018] The concentrated water from the primary reverse osmosis device enters the secondary reverse osmosis device, the concentrated water from the secondary reverse osmosis device enters the tertiary reverse osmosis device, and the concentrated water from the tertiary reverse osmosis device enters the MVR evaporation device;

[0019] The produced water of the primary reverse osmosis device, the secondary reverse osmosis device, the high-pressure reverse osmosis device and the evaporated condensed water of the MVR evaporation device all flow into the reuse water tank.

[0020] Aiming at the characteristics of low organic matter concentration and high fluoride and SS concentration in the wastewater of integrated circuit board industry, the present invention designs a special defluorination reactor for etching tank liquid, which is then mixed with the wastewater from the incinerator washing tower and further treated by a secondary physicochemical treatment system, an MBR membrane bioreactor and a tertiary reverse osmosis system before being reused in the incinerator washing tower. The wastewater treatment efficiency is high and the reuse rate reaches more than 98%.

[0021] Furthermore, the defluorination reactor uses calcium hydroxide to react with HF to produce calcium fluoride precipitation, and uses a coagulant PAM to assist the coagulation and precipitation of calcium fluoride particles; because there is a certain amount of NH 4 F, NaF and NaOH, these chemicals entering the system will cause the pH to rise, causing the total amount of calcium hydroxide valve linkage dosing to decrease, thereby reducing the amount of calcium added, causing the fluorine concentration to increase. Therefore, sulfuric acid is needed to neutralize these chemicals. The precipitation reaction of calcium and fluorine requires the addition of excess calcium. The purpose of adding excess sulfuric acid is to further reduce the pH of the inlet water, and to achieve a high calcium-fluorine ratio in line with the theoretical value, in order to achieve a further reduction in the fluorine value. In S1, the defluorination reactor includes the following chemical reactions:

[0022] 2HF+Ca(OH) 2 =2H 2 O+CaF 2 ;

[0023] 2NaF+H 2 SO 4 =2HF+Na 2 SO 4 ;

[0024] 2NaOH+H 2 SO 4 =Na 2 SO 4 +2H 2 O;

[0025] 2NH 4 F+H 2 SO 4 =(NH 4 ) 2 SO 4 +2HF;

[0026] H 2 SiF 6 +Ca(OH) 2 =CaSiF 6 +2H 2 O;

[0027] CaSiF 6 +2Ca(OH) 2 =3CaF2 +SiO 2 +2H 2 O.

[0028] The high-density sludge reflow method uses a combination of calcium hydroxide and sulfuric acid to remove fluorine. It does not require the addition of calcium carbonate seeds. The calcium carbonate added in the existing defluorination process is a poorly soluble substance. After contacting with water, it finally reacts to form calcium hydroxide, which prolongs the reaction time and reduces the defluorination efficiency. At the same time, the reaction is exothermic, which poses a safety hazard. During the system debugging process, the calcium fluoride and calcium sulfate produced by the reaction are flocculated and precipitated, and then returned to the high-density sludge tank as seeds. After the sludge particles absorb calcium hydroxide, they enter the reaction tank to react with the fluoride-containing wastewater. The generated calcium fluoride gradually grows on the seeds, and the CaF in the defluorination reactor grows. 2 The particle size is ≥16.97μm, and the equilibrium total fluorine concentration is <8mg / L.

[0029] Through sludge return, the newly generated calcium fluoride acts as a crystallization center, adsorbing and precipitating, thereby reducing the solubility of calcium fluoride. At the same time, sludge return can return the remaining unreacted calcium hydroxide in the sludge to the reaction tank for further reaction. Compared with the traditional process without sludge return, it can achieve a 33.3% reduction in calcium hydroxide and significantly reduce the water content of the sludge.

[0030] Furthermore, in S1, sulfuric acid and slaked lime are added to the defluorination reactor to adjust the pH to 5-9, specifically: sulfuric acid is added until the pH is less than 5, and then slaked lime is added until the pH is 5-9. When the pH value is too low, F - Partially formed HF or HF 2- , reduce F - concentration; when the pH value is too high, LaF 3 F in membrane - With OH in solution - Exchange occurs, and La(OH) is formed on the crystal surface 3 The release of F - In the defluorination reactor, as the amount of sulfuric acid added increases, fluoride ions are further removed. Preferably, the sulfuric acid addition concentration is 600 mg / L to 800 mg / L, and the pH is adjusted to 7.5 to 7.9. At this time, the fluoride outlet water concentration can reach below 8 mg / L.

[0031] Further, sulfuric acid was added to pH = 2.0, and then slaked lime was added to pH 7.5.

[0032] Furthermore, in the HDS process, calcium hydroxide and sludge are recycled, the moisture content of the output sludge reaches less than 40%, and the mud cake is dried. In general traditional treatment methods, the sludge moisture content is 60% to 70%, while the HDS process can reach a moisture content of 20% to 40%. The main reason is that the sludge particles are sent back to the HDS tank and first adsorb calcium hydroxide, thereby reducing the moisture between the sludge particles, thereby reducing the moisture in the sludge structure and enhancing the dehydration performance.

[0033] Further, in S21, the reaction-precipitation integrated machine comprises a first reaction zone, a second reaction zone, a third reaction zone and a precipitation zone connected in sequence;

[0034] The first reaction zone adds calcium chloride and slaked lime to adjust the pH to 8-9 and produce CaF 2 The second reaction zone is added with PAC, the pH is adjusted to 6-7, and a coagulation reaction occurs; the third reaction zone is added with PAM, and the flocs are coagulated.

[0035] The first reaction zone of the reaction-precipitation integrated machine is dosing Ca(OH) 2 and CaCl 2 Fluoride ions generate CaF 2 Sedimentation; then the wastewater flows into the second reaction zone, and the coagulant PAC is added to make CaF 2 The precipitation generates larger particles; then the wastewater flows into the third reaction zone by gravity, and the flocculant PAM is added to increase the CaF 2 Sedimentation effect: The wastewater after flocculation reaction flows into the inclined tube sedimentation tank by gravity, and the solid-liquid separation is achieved through sedimentation, and the sludge is precipitated and concentrated at the same time.

[0036] The MVR evaporation device needs to strictly control the pH value during operation, and pH value adjustment is particularly critical, so a two-stage physicochemical process of reaction sedimentation integrated machine + flotation tank is set up for multi-stage adjustment. In order to meet the water quality before entering the three-stage reverse osmosis system, MBR is used to remove organic matter while filtering fine particles to make SS less than 50 mg / L and particle size less than or equal to 0.5 μm. The loss of MBR activated sludge is almost zero, so its activated sludge concentration is 2 to 6 times higher than that of traditional processes. This technology can also control the activated sludge age and hydraulic retention time respectively, so this method can greatly improve the SS removal efficiency and the removal efficiency of organic pollutants.

[0037] Furthermore, in S4, the first-stage reverse osmosis device is a low-pressure reverse osmosis membrane, the second-stage reverse osmosis device is a high-pressure salt-resistant reverse osmosis membrane, and the third-stage reverse osmosis device is a disc-tube reverse osmosis membrane.

[0038] Furthermore, in S1, a perforated aeration tank connected to a Roots blower is provided in the comprehensive regulating tank to make the quality and quantity of the wastewater uniform.

[0039] The second aspect of the present invention provides a device for recycling wastewater from an incinerator washing tower and water from an etching tank, which is used to implement the method described in the first aspect, and comprises a comprehensive regulating tank, a reaction and precipitation integrated machine, a flotation tank, an MBR membrane bioreactor, a primary reverse osmosis device, a secondary reverse osmosis device, a tertiary reverse osmosis device and an MVR evaporation device connected in sequence;

[0040] The comprehensive regulating tank is also connected to the defluorination reactor to collect the effluent from the defluorination reactor and mix it with the wastewater from the incinerator washing tower;

[0041] The water outlets of the primary reverse osmosis device, the secondary reverse osmosis device, the tertiary reverse osmosis device and the MVR evaporation device are all connected to the recycled water tank;

[0042] The water outlet of the recycled water tank is connected to the water inlet of the incinerator washing tower.

[0043] Furthermore, the reaction-precipitation integrated machine comprises a first reaction zone, a second reaction zone, a third reaction zone and a precipitation zone which are connected in sequence, and the precipitation zone is an inclined tube sedimentation tank.

[0044] Furthermore, it also includes a sludge pool and a sludge dewatering machine connected to the sludge pool, and the sludge pool is used to collect sludge from the defluorination reactor, the reaction sedimentation integrated machine and the flotation tank.

[0045] Beneficial effects of the present invention:

[0046] The present invention classifies and collects wastewater from incinerator washing towers and etching tank liquid in the integrated circuit board industry, removes fluorine from the etching tank liquid wastewater in a defluorination reactor and then mixes it with wastewater from incinerator washing towers, and sequentially enters a secondary physicochemical treatment system, an MBR membrane bioreactor and a tertiary reverse osmosis system for treatment. The wastewater treatment is efficient, and the reuse rate of reclaimed water is high, with a reuse rate of more than 98%.

[0047] The defluorination reactor of the present invention adopts a high-density sludge reflux method for defluorination, uses a combination of calcium hydroxide and sulfuric acid, and does not need to add calcium carbonate seeds, thereby avoiding the problem that calcium carbonate is added in the defluorination process in the prior art, and calcium hydroxide is finally reacted to form calcium hydroxide after contact with water, which prolongs the reaction time, reduces the defluorination efficiency, and has safety hazards due to the heat release of the reaction; the high-density sludge reflux method is used for defluorination, and the water content of the sludge can be as low as 40%, which is much lower than the sludge water content of 65%-70% in the flocculation method.

[0048] The water recycling device of the present invention has a small footprint and strong mobility, and also has a low operating cost and a high degree of automation. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the embodiments are briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0050] Figure 1 The present invention is a flow chart of a method for recycling waste water from an incinerator washing tower and water from an etching tank. DETAILED DESCRIPTION

[0051] The technical solution of the present invention will be described clearly and completely below in conjunction with the specific embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0052] This embodiment relates to a method for recycling wastewater from a washing tower of an integrated circuit board incinerator and water from an etching tank. The process flow chart is as follows: Figure 1 As shown, the sources of wastewater to be treated are mainly: incinerator washing tower wastewater and etching tank liquid, among which the TSS (suspended solids) in the incinerator washing tower wastewater is 33 mg / L, and the TDS (total dissolved solids) is 260 mg / L; the HF content of the etching tank liquid is 70000 mg / L. The specific method of reclaimed water reuse includes the following steps:

[0053] (1) After the etching bath liquid passes through the defluorination reactor, it is mixed with the wastewater from the incinerator washing tower in the comprehensive regulating tank;

[0054] The defluorination reactor adopts a high-density sludge reflux method to remove fluorine, and the sludge mass concentration is 15%; 757 mg / L sulfuric acid is added to the defluorination reactor to pH = 2.0, and then 1635 mg / L slaked lime is added to pH 7.5; 5 mg / L of coagulant PAM is added to assist the coagulation and precipitation of calcium fluoride particles, and 350 mg / L of PAC is added to promote flocculation and precipitation.

[0055] (2) The effluent from the comprehensive regulating tank enters a reaction-precipitation integrated machine, which includes a first reaction zone, a second reaction zone, a third reaction zone and a precipitation zone connected in sequence; 2400 mg / L of calcium chloride and 720 mg / L of slaked lime are added to the first reaction zone to adjust the pH to 8.2 and produce CaF 2 The second reaction zone was added with 550 mg / L PAC, the pH was adjusted to 6.7, and a coagulation reaction occurred; the third reaction zone was added with 8 mg / L PAM, and the flocs were coagulated.

[0056] (3) The effluent from the sedimentation area enters the flotation tank, where 80 mg / L of alkali solution (sodium hydroxide) is added to adjust the pH to 7.8, and 120 mg / L of PAC and 3 mg / L of PAM are added to remove suspended particles in the wastewater and reduce the SS (suspended matter) concentration.

[0057] (4) The effluent from the flotation tank enters the MBR membrane bioreactor and is intercepted and filtered by the hollow fiber membrane and biodegraded by microorganisms under aerobic conditions to remove dissolved organic matter and colloidal substances in the wastewater, and further remove SS.

[0058] (5) The effluent from the MBR membrane bioreactor enters the primary reverse osmosis device, the concentrated water from the primary reverse osmosis device enters the secondary reverse osmosis device, the concentrated water from the secondary reverse osmosis device enters the tertiary reverse osmosis device, and the concentrated water from the tertiary reverse osmosis device enters the MVR evaporation device; the crystals from the MVR evaporation device are transported out; the produced water from the primary reverse osmosis device, the secondary reverse osmosis device, the high-pressure reverse osmosis device, and the evaporated condensed water from the MVR evaporation device all flow into the reuse water tank and are used as water for the incinerator scrubber.

[0059] During the process, the sludge from the defluorination reactor, reaction sedimentation integrated machine and flotation tank is discharged into the sludge pool for static concentration, and then pumped into the sludge dewatering machine for dehydration to a moisture content of 50% to 60% for external transportation.

[0060] The incinerator washing tower wastewater and etching tank liquid water recycling method of the present invention treats the integrated circuit board industry wastewater. After the treatment, the fluoride in the wastewater is 6-8 mg / L, the removal rate is more than 99.9%, and the water recycling rate is as high as 98%. The HDS process makes most of the sludge return to significantly reduce the treatment volume, low operating costs, high degree of automation, and efficient and stable treatment effect and recycling rate.

[0061] Another embodiment of the present invention provides a device for recycling wastewater from an incinerator washing tower and water from an etching tank, which is used to implement the method described in the above embodiment. Figure 1 , including a comprehensive regulating tank, a reaction-precipitation integrated machine, a flotation tank, an MBR membrane bioreactor, a primary reverse osmosis device, a secondary reverse osmosis device, a tertiary reverse osmosis device and an MVR evaporation device connected in sequence; the comprehensive regulating tank is also connected to a defluorination reactor to collect the effluent from the defluorination reactor and mix it with the wastewater from the incinerator washing tower; the water outlets of the primary reverse osmosis device, the secondary reverse osmosis device, the tertiary reverse osmosis device and the MVR evaporation device are all connected to a reuse water tank; the water outlet of the reuse water tank is connected to the water inlet of the incinerator washing tower.

[0062] As a specific example, the reaction-precipitation integrated machine includes a first reaction zone, a second reaction zone, a third reaction zone and a precipitation zone connected in sequence, and the precipitation zone is an inclined tube sedimentation tank.

[0063] Preferably, it also includes a sludge pool and a sludge dewatering machine connected to the sludge pool, and the sludge pool is used to collect sludge from the defluorination reactor, the reaction sedimentation integrated machine and the flotation tank.

[0064] In summary, the present invention collects wastewater from incinerator washing towers and etching tank liquid in the integrated circuit board industry by classification, removes fluorine from the etching tank liquid wastewater through a defluorination reactor, and then mixes it with the wastewater from the incinerator washing tower, and sequentially enters a secondary physicochemical treatment system, an MBR membrane bioreactor, and a tertiary reverse osmosis system for treatment, so that the wastewater treatment is efficient, and the reuse rate of the reclaimed water is high, and the reuse rate reaches more than 98%; the defluorination reactor adopts a high-density sludge reflux method for defluorination, uses a combination of calcium hydroxide and sulfuric acid, and does not need to add calcium carbonate seeds, thereby avoiding the problem that calcium carbonate is added in the defluorination process in the prior art, and finally reacts to generate calcium hydroxide after contacting with water, prolonging the reaction time, reducing the defluorination efficiency, and causing safety hazards due to the heat release of the reaction; the high-density sludge reflux method is used for defluorination, and the sludge water content can be as low as 40%, which is much lower than the sludge water content of 65%-70% in the flocculation method; the reclaimed water reuse device occupies a small area and has strong mobility, while having low operating costs and a high degree of automation.

[0065] The present invention has been described in detail above in conjunction with specific implementations and exemplary examples, but these descriptions cannot be understood as limiting the present invention. Those skilled in the art understand that, without departing from the spirit and scope of the present invention, a variety of equivalent substitutions, modifications or improvements may be made to the technical solution of the present invention and its implementation methods, all of which fall within the scope of the present invention. The scope of protection of the present invention shall be subject to the attached claims.

Claims

1. A method for recycling wastewater from an incinerator scrubber and water from an etching tank, characterized in that: The steps include: S1, the etching tank liquid is mixed with the wastewater from the incinerator washing tower in a comprehensive regulating tank after passing through the defluorination reactor; The defluorination reactor adopts a high-density sludge reflux method to remove fluorine, and the sludge mass concentration is 15%-20%; sulfuric acid and slaked lime are added to the defluorination reactor to adjust the pH to 5-9; 3mg / L-10mg / L PAM and 300mg / L-500mg / L PAC are also added to the defluorination reactor; In S1, sulfuric acid and slaked lime are added to the defluorination reactor to adjust the pH to 5-9, specifically: sulfuric acid is added until the pH is less than 5, and then slaked lime is added until the pH is 5-9; In S1, the defluorination reactor includes the following chemical reactions: 2HF+Ca(OH)2=2H2O+CaF2; 2NaF+H2SO4=2HF+Na2SO4; 2NaOH+H2SO4=Na2SO4+2H2O; 2NH4F+H2SO4=(NH4)2SO4+2HF; H2SiF6+Ca(OH)2=CaSiF6+2H2O; CaSiF6+2Ca(OH)2=3CaF2+SiO2+2H2O; S2. The effluent from the comprehensive regulating pool enters the secondary physical and chemical treatment system, which specifically includes: S21, the effluent from the comprehensive regulating tank enters the reaction precipitation integrated machine, and calcium chloride, slaked lime, PAC and PAM are added to further remove fluoride; S22, the supernatant of the effluent from the reaction-precipitation integrated machine flows into the flotation tank by gravity, and alkali solution, PAC and PAM are added to remove suspended particles in the wastewater and reduce SS concentration; S3, the effluent from the flotation tank flows into the membrane bioreactor by gravity, and the soluble organic matter and colloidal substances in the wastewater are removed through interception and filtration of the hollow fiber membrane and biodegradation of microorganisms under aerobic conditions, and SS is further removed to <50 mg / L, and the particle size of the effluent particles is below 0.5 μm; S4, the effluent from the membrane bioreactor enters a three-stage reverse osmosis system, wherein the three-stage reverse osmosis system comprises a primary reverse osmosis device, a secondary reverse osmosis device, a tertiary reverse osmosis device and an MVR evaporation device connected in sequence; The concentrated water from the primary reverse osmosis device enters the secondary reverse osmosis device, the concentrated water from the secondary reverse osmosis device enters the tertiary reverse osmosis device, and the concentrated water from the tertiary reverse osmosis device enters the MVR evaporation device; The produced water of the primary reverse osmosis device, the secondary reverse osmosis device, the high-pressure reverse osmosis device, and the evaporated condensed water of the MVR evaporation device all flow into the reuse water tank.

2. The method for recycling wastewater from an incinerator scrubber and water from an etching tank as claimed in claim 1, characterized in that: In S1, sulfuric acid and slaked lime are added to the defluorination reactor to adjust the pH to 5-9, specifically: sulfuric acid is added to pH=2.0, and then slaked lime is added to pH 7.

5.

3. The method for recycling wastewater from an incinerator scrubber and water from an etching tank as claimed in claim 1, characterized in that: In S21, the reaction-precipitation integrated machine comprises a first reaction zone, a second reaction zone, a third reaction zone and a precipitation zone connected in sequence; Among them, calcium chloride and slaked lime are added to the first reaction zone to adjust the pH to 8-9 and produce CaF2 precipitation; PAC is added to the second reaction zone to adjust the pH to 6-7 and produce coagulation reaction; PAM is added to the third reaction zone to cause floc coagulation.

4. The method for recycling wastewater from an incinerator scrubber and water from an etching tank as claimed in claim 1, characterized in that: In S4, the first-stage reverse osmosis device is a low-pressure reverse osmosis membrane, the second-stage reverse osmosis device is a high-pressure salt-resistant reverse osmosis membrane, and the third-stage reverse osmosis device is a disc-tube reverse osmosis membrane.

5. The method for recycling wastewater from an incinerator scrubber and water from an etching tank as claimed in claim 1, characterized in that: In S1, a perforated aeration tank connected to a Roots blower is arranged in the comprehensive regulating tank to make the wastewater quality and quantity uniform.

6. A device for recycling wastewater from an incinerator washing tower and water from an etching tank, used for implementing the method according to any one of claims 1 to 5, characterized in that: It includes a comprehensive regulating tank, a reaction sedimentation integrated machine, a flotation tank, a membrane bioreactor, a primary reverse osmosis device, a secondary reverse osmosis device, a tertiary reverse osmosis device and an MVR evaporation device connected in sequence; The comprehensive regulating tank is also connected to the defluorination reactor to collect the effluent from the defluorination reactor and mix it with the wastewater from the incinerator washing tower; The water outlets of the primary reverse osmosis device, the secondary reverse osmosis device, the tertiary reverse osmosis device and the MVR evaporation device are all connected to the recycled water tank; The water outlet of the recycled water tank is connected to the water inlet of the incinerator washing tower.

7. The incinerator washing tower wastewater and etching tank liquid water recycling device as claimed in claim 6, characterized in that: The reaction-precipitation integrated machine comprises a first reaction zone, a second reaction zone, a third reaction zone and a precipitation zone which are sequentially connected, and the precipitation zone is an inclined tube precipitation tank.

8. The device for recycling wastewater from an incinerator washing tower and water from an etching tank as claimed in claim 6, characterized in that: It also includes a sludge pool and a sludge dewatering machine connected to the sludge pool. The sludge pool is used to collect sludge from the defluorination reactor, the reaction and precipitation integrated machine and the flotation tank.

Images