CN111268830A - System and process for advanced treatment and recycling of fluorine-containing wastewater in electronic industry - Google Patents
System and process for advanced treatment and recycling of fluorine-containing wastewater in electronic industry Download PDFInfo
- Publication number
- CN111268830A CN111268830A CN202010247900.1A CN202010247900A CN111268830A CN 111268830 A CN111268830 A CN 111268830A CN 202010247900 A CN202010247900 A CN 202010247900A CN 111268830 A CN111268830 A CN 111268830A
- Authority
- CN
- China
- Prior art keywords
- fluorine
- containing wastewater
- concentration
- water
- tank
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F9/00—Multistage treatment of water, waste water or sewage
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/001—Processes for the treatment of water whereby the filtration technique is of importance
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/28—Treatment of water, waste water, or sewage by sorption
- C02F1/281—Treatment of water, waste water, or sewage by sorption using inorganic sorbents
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/28—Treatment of water, waste water, or sewage by sorption
- C02F1/283—Treatment of water, waste water, or sewage by sorption using coal, charred products, or inorganic mixtures containing them
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/42—Treatment of water, waste water, or sewage by ion-exchange
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
- C02F1/441—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by reverse osmosis
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/50—Treatment of water, waste water, or sewage by addition or application of a germicide or by oligodynamic treatment
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
- C02F1/54—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using organic material
- C02F1/56—Macromolecular compounds
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/12—Halogens or halogen-containing compounds
- C02F2101/14—Fluorine or fluorine-containing compounds
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2301/00—General aspects of water treatment
- C02F2301/08—Multistage treatments, e.g. repetition of the same process step under different conditions
Abstract
The invention relates to a fluorine-containing wastewater advanced treatment and recycling system and a process in the electronic industry, wherein the system comprises an adjusting tank, a first multi-media filter, an activated carbon filter, a softening device, a filter water tank, a security filter, an RO system, a fluorine-containing wastewater temporary storage tank, a high-concentration fluorine-containing wastewater primary-treatment mixing system, a high-concentration fluorine-containing wastewater secondary-depth fluorine removal system, a second multi-media filter, a fluorine-removing resin tower and a drainage tank which are sequentially connected through pipelines, the adjusting tank is connected with a fluorine-containing wastewater inlet pipe, and the drainage tank is connected with a standard discharge pipe. The process comprises the following steps: the first step is as follows: a fluorine-containing wastewater conditioning system; the second step is that: a reverse osmosis filtration system; the third step: a high-concentration fluorine-containing wastewater first-stage mixing system; the fourth step: a high-concentration fluorine-containing wastewater two-stage deep fluorine removal system; the fifth step: a defluorination resin system. The invention has the advantages that: the combined process of RO concentration, two-stage mixing, fluorine removal agent addition and fluorine removal resin is adopted to realize the purpose of advanced treatment and recycling of fluorine-containing wastewater in the electronic industry.
Description
Technical Field
The invention relates to a technology for advanced treatment of fluorine-containing wastewater in the electronic industry, in particular to a system and a process for advanced treatment and recycling of fluorine-containing wastewater in the electronic industry, belonging to the technical field of water treatment.
Background
In the production process of products in the electronic industry (such as semiconductors, panels, photovoltaics and the like), hydrofluoric acid, ammonium fluoride and other materials are used in the pickling operation, the wet etching process and the like, and further wastewater containing fluorine ions is generated. The fluorine-containing wastewater is usually the second and third washing water of the process, and has the characteristics of large water quantity, less impurities, acidic inlet water (pH of about 1-3) and the like.
In the prior art, fluoride ions in water are removed by adding calcified mixed sediment, adding a fluorine removal agent and the like. The calcium adding chemical mixing process can only remove F in water to about 10-20 mg/L, cannot meet the existing discharge standard, and has the problems of large dosage, high sludge yield, damage to subsequent processes caused by calcium ion scale remaining in water and the like; the process of adding the defluorinating agent is directed to adding the defluorinating agent into the first-stage calcified mixed effluent, the effective components such as aluminum, iron and the like in the defluorinating agent and fluoride ions form sludge to precipitate, and F in the water can be reduced to be below 3 or 1mg/L, so that the existing discharge requirement is met, but the defluorinating agent is high in cost and large in adding amount and is generally applied to projects with small water quantity.
Chinese patent CN201010525143.6 & lt & ltphotovoltaic wastewater defluorination method & gt, calcium hydroxide is added to adjust the pH of wastewater to 8.5-9.5 for chemical mixing and precipitation, the chemical mixing effluent is further subjected to air floatation to remove colloids and suspended matters in water, and the treated wastewater passes through a modified dual-resin ion exchanger column containing gel strong acid type Al-type ion exchange resin and macroporous weak acid type Al-type ion exchange resin. The method combines the calcium adding mixing process with the fluorine removal resin process, so that the fluorine content of the effluent is stably less than 3ppm, but the two-stage resin tower is adopted for adsorption, the resin consumption is high, the initial cost and the subsequent resin regeneration cost are high, and the fluorine-containing wastewater is not recycled.
Chinese patent CN 201811613176.9A method for treating fluorine-containing wastewater, which comprises the following specific steps: firstly, adding lime water solution to adjust the pH value of the fluorine-containing wastewater to 8-9, then adding 0.3-0.4% of alum, simultaneously controlling the pH value to be 10-11, and adding polyacrylamide solution to carry out chemical mixing and precipitation. The method can only treat the fluorine in the wastewater to be below 5ppm by adding lime and alum, and the method is far from reaching the discharge standard for some areas with strict fluorine discharge requirements.
Chinese patent CN201910319768.8 application of an efficient defluorinating agent in industrial wastewater, wherein the defluorinating agent is used for treating the fluorine-containing wastewater, the defluorinating agent is a composite agent of an organic high-molecular cationic polymer and a nano iron silicate polymer, the content of the nano iron silicate polymer in the composite coagulant is 5-10%, the content of the organic high-molecular cationic polymer in the composite coagulant is 3-10%, and the defluorinating agent is respectively added in a two-stage mixing section to reduce the fluorine ions in various fluorine-containing industrial wastewater to be within 1 mg/L. However, the method has the disadvantages of complex preparation process and high preparation cost of the defluorinating agent, and simultaneously, the addition amount of the defluorinating agent is large (5000-6000 mg/L) because the defluorinating agent is respectively added in the two-stage mixing section, the sludge yield is increased rapidly, the operation cost is high, and the method is not suitable for treating the fluorine-containing wastewater with large water amount in the electronic industry.
As can be seen from the above, the prior art has the following problems: the fluorine in the wastewater is difficult to remove to below 1mg/L by the conventional calcium-adding chemical-mixing precipitation, and the problems of large dosage, high sludge yield, damage to the subsequent process caused by calcium ion scaling remained in water and the like exist; the fluorine-containing wastewater treated by adding the fluorine-removing agent can treat fluorine in the wastewater to a lower level, but the problems of large dosage, high operation cost and the like generally exist; the fluorine-containing wastewater treated by adopting the special fluorine-removing resin process has the problems of high initial investment, high resin consumption, high calcium and magnesium content of resin inlet water, easy scaling and the like; aiming at the characteristic of larger water volume of the fluorine-containing wastewater in the electronic industry, the treatment effect and the economy are difficult to be considered by singly adopting a medicine or resin adding mode, and meanwhile, the recycling of the fluorine-containing wastewater cannot be realized.
Disclosure of Invention
The invention provides a fluorine-containing wastewater advanced treatment and recycling system and process in the electronic industry, aiming at solving the problems that the conventional process of the fluorine-containing wastewater in the electronic industry is difficult to treat the fluorine-containing wastewater to be below 1mg/L, the treatment effect and the economy are difficult to be considered by singly adopting a medicine or resin mode, the recycling of the fluorine-containing wastewater cannot be realized, and the like, and providing the fluorine-containing wastewater advanced treatment process which can effectively reduce the medicine adding cost, reduce the resin consumption, save energy, reduce consumption and finally realize the wastewater recycling.
The technical solution of the invention is as follows: a fluorine-containing wastewater advanced treatment and recycling process in the electronic industry comprises the following process steps:
the first step is as follows: fluorine-containing wastewater adjusting system: lifting the fluorine-containing wastewater to a fluorine-containing wastewater adjusting tank by a pump to uniform the water quality and water quantity, and adjusting the pH to 7-8;
the second step is that: reverse osmosis filtration system: the effluent of the fluorine-containing wastewater adjusting tank sequentially passes through a multi-media filter, an activated carbon filter and a softening device to remove suspended substances, partial organic matters and calcium and magnesium hardness in water, then the fluorine-containing wastewater with the hardness of less than 1mg/L is treated by the softening device, the fluorine-containing wastewater enters an RO system after the pH is adjusted, the recovery rate of the RO system is more than 70 percent, the permeate effluent of the RO system returns to a front-end pure water system for recycling, and the reverse osmosis concentrated water enters a high-concentration fluorine-containing wastewater first-stage mixing system;
the third step: high concentration fluorine-containing waste water first-stage chemical mixing system: the reverse osmosis concentrated water is concentrated high-concentration fluorine-containing wastewater, after the pH is adjusted to be 7-9, a single type of fluorine removal agent is added, the full reaction is carried out for 20-30 min, calcium fluoride precipitate is formed with fluorine ions in the wastewater, polyacrylamide is added for reaction for 0.25h, water is discharged after flocculation precipitation is carried out for 2-3 h, the concentration of fluorine in the water is 15-20 mg/L, and the water enters a secondary deep fluorine removal system for the high-concentration fluorine-containing wastewater;
the fourth step: high concentration fluorine waste water second grade degree of depth defluorination system: adding a compound type deep fluorine removal agent, reacting for 0.5h, adjusting the pH of the effluent to 6-7, adding polyacrylamide, reacting for 0.25h, performing flocculation precipitation for 2-3 h, and allowing the effluent to enter a fluorine removal resin system, wherein the fluorine concentration in the wastewater is 3-6 mg/L;
the fifth step: defluorination resin system: the effluent of the secondary deep fluorine removal system of the high-concentration fluorine-containing wastewater enters a multi-medium filter to remove colloids and suspended substances in water, the filtered effluent enters a fluorine removal resin tower for deep treatment, aluminum-containing groups of resin are used for adsorbing fluorine ions in water, the effluent of the resin is stably treated to be below 1mg/L, and the concentrated resin water returns to the primary mixing system of the high-concentration fluorine-containing wastewater for continuous treatment.
Preferably, in the reverse osmosis filtration system of the second step, a pH adjusting unit, a bactericide adding unit and a coagulant adding unit are arranged in front of the multi-media filter, the pH of the fluorine-containing wastewater is adjusted to be neutral before the fluorine-containing wastewater flows into the multi-media filter, the fluorine-containing wastewater flows into the multi-media filter after the coagulant is added, and then the fluorine-containing wastewater filtered by the multi-media filter flows into the activated carbon filter.
Preferably, in the first-stage mixed system of the high-concentration fluorine-containing wastewater in the third step, the single type of fluorine removal agent is a calcium chloride solution with a mass concentration of 30% or a calcium hydroxide solution with a mass concentration of 10%.
Preferably, the addition amount of the calcium chloride is 0.6-0.65 in terms of molar ratio Ca/F, and the concentration of the polyacrylamide is 3 mg/L.
Preferably, in the fourth step of the secondary deep fluorine removal system for the high-concentration fluorine-containing wastewater, the concentration of the composite deep fluorine removal agent is 200-500 mg/L, and the concentration of the polyacrylamide is 3 mg/L.
Preferably, the composite type deep fluorine removal agent is prepared from polyaluminium chloride, activated alumina, calcium fluoride, polyferric chloride and a modified molecular sieve, and the pH value is 1-3.
Preferably, the mass ratio of the polyaluminium chloride, the activated alumina, the calcium fluoride, the polyferric chloride and the modified molecular sieve is 50: 20: 5: 20: 5.
preferably, the purity of the polyaluminum chloride is defined as Al2O3The content is more than or equal to 28 percent.
Preferably, in the fluorine-removing resin system of the fifth step, the effluent of the fluorine-removing resin tower is provided with a pH adjusting unit and a fluorine ion online monitor, the pH of the effluent treated by the fluorine-removing resin tower is adjusted to 6.5-8.5, and the effluent reaching the standard flows into a drainage pool; if the quality of the discharged water is unqualified, the unqualified water is refluxed to a high-concentration fluorine-containing wastewater first-stage mixing system for treatment by switching a valve and a pipeline.
Preferably, the method further comprises the following steps: and (3) guiding precipitates generated by the high-concentration fluorine-containing wastewater first-stage mixing system and the high-concentration fluorine-containing wastewater second-stage deep defluorination system into a filter press for dehydration treatment, returning the squeezed water to the high-concentration fluorine-containing wastewater first-stage mixing system for treatment, and carrying out external treatment on the generated mud cakes.
The utility model provides an electron trade fluorine-containing waste water advanced treatment and recycling system, include the equalizing basin that connects gradually through the pipeline, first many medium filter, activated carbon filter, softening installation, filter water tank, safety filter ware, the RO system, fluorine-containing waste water keeps in the pond, high concentration fluorine-containing waste water one-level ization mixes the system, high concentration fluorine-containing waste water second grade degree of depth defluorination system, the many medium filter of second, defluorination resin tower and pond of releasing, the equalizing basin is connected fluorine-containing waste water and is advanced the pipe, the pond of releasing is connected up to standard delivery pipe.
Preferably, the high-concentration fluorine-containing wastewater first-stage mixing system comprises a reaction tank A, a coagulation tank A, a flocculation tank A, a sedimentation tank A and an intermediate water tank A which are connected in sequence, and the high-concentration fluorine-containing wastewater second-stage deep defluorination system comprises a reaction tank B, a pH adjusting tank, a flocculation tank B, a sedimentation tank B and an intermediate water tank B which are connected in sequence; the A sedimentation tank and the B sedimentation tank are respectively connected with a sludge storage tank through pipelines, and the sludge storage tank is sequentially connected with a plate-and-frame filter press, a filtrate tank and a fluorine-containing wastewater temporary storage tank through pipelines; a pH adjusting unit is arranged in the adjusting tank, and a bactericide dosing unit and a coagulant dosing unit are connected on a pipeline between the adjusting tank and the multi-medium filter; the releasing pool is connected with a fluorine-containing wastewater temporary storage pool through a pipeline, a water outlet of the defluorination resin tower is connected with the releasing pool through a pipeline, a pH adjusting unit and a fluorine ion online monitor are arranged on the pipeline between the defluorination resin tower and the releasing pool, and a concentrated water outlet of the defluorination resin tower is connected with the releasing pool and the fluorine wastewater temporary storage pool through a pipeline.
The invention has the advantages that: the combined process of RO concentration, two-stage mixing, fluorine removal agent addition and fluorine removal resin is adopted to realize the purpose of advanced treatment and recycling of fluorine-containing wastewater in the electronic industry. Specifically, the method comprises the following steps:
firstly, according to the characteristics of less impurities and larger water quantity of the fluorine-containing wastewater in the electronic industry, the RO process is adopted to carry out concentration treatment on the fluorine-containing wastewater, RO outlet water is recycled to a front-end pure water system, and RO concentrated water enters a high-concentration fluorine-containing wastewater treatment system, so that the recycling of the fluorine-containing wastewater is realized, the treatment scale of the fluorine-containing wastewater is reduced, and the treated water quantity and the treated load of a chemical mixing system are reduced.
And secondly, treating the high-concentration fluorine-containing wastewater by adopting a combined process of two-stage mixed adding of a fluorine removal agent and fluorine removal resin, wherein the fluorine in the effluent can be stably less than 1mg/L, so that the requirement of deep fluorine removal of an owner is met, and meanwhile, the fluorine in the resin inflow is reduced to 5-10 mg/L by adding the fluorine removal agent, so that the dosage of the fluorine removal resin can be greatly reduced, the regeneration cost is reduced, and the primary cost and the operating cost are reduced.
Drawings
FIG. 1 is a flow chart of the advanced treatment and recycling process of fluorine-containing wastewater in the electronic industry.
FIG. 2 is a block diagram of the fluorine-containing wastewater advanced treatment and recycling system in the electronic industry.
In the figure, 1 is a regulating tank, 2 is a first multimedia filter, 3 is an activated carbon filter, 4 is a softening device, 5 is a filtration water tank, 6 is a cartridge filter, 7 is an RO system (reverse osmosis system), 8 is a fluorine-containing wastewater temporary storage tank, 9 is an A reaction tank, 10 is an A coagulation tank, 11 is an A flocculation tank, 12 is an A sedimentation tank, 13 is an A intermediate water tank, 14 is a B reaction tank, 15 is a pH regulating tank, 16 is a B flocculation tank, 17 is a B sedimentation tank, 18 is a B intermediate water tank, 19 is a second multimedia filter, 20 is a fluorine removal resin tower, 21 is a bleed flow tank, 22 is a sludge storage tank, 23 is a plate-and-frame filter press, and 24 is a filtrate tank.
Detailed Description
The present invention will be described in further detail with reference to examples and specific embodiments.
As shown in figure 2, the advanced treatment and recycling system for the fluorine-containing wastewater in the electronic industry structurally comprises a regulating reservoir 1, a first multi-media filter 2, an activated carbon filter 3, a softening device 4, a filter water tank 5, a security filter 6, an RO system 7, a temporary storage pool 8 for the fluorine-containing wastewater, a primary high-concentration fluorine-containing wastewater mixing system, a secondary high-concentration fluorine-containing wastewater deep fluorine removal system, a second multi-media filter 19, a fluorine-removing resin tower 20 and a flow discharging pool 21 which are sequentially connected through pipelines, wherein the regulating reservoir 1 is connected with a fluorine-containing wastewater inlet pipe, and the flow discharging pool 21 is connected with a standard discharge pipe.
High concentration fluorine-containing waste water one-level ization mixes system including A reaction tank 9, A coagulation basin 10, A flocculation basin 11, A sedimentation tank 12 and the middle pond 13 of A that connects gradually, high concentration fluorine-containing waste water second grade degree of depth defluorination system including the middle pond 18 of B reaction tank 14, pH equalizing basin 15, B flocculation basin 16, B sedimentation tank 17 and the B that connect gradually.
The A sedimentation tank 12 and the B sedimentation tank 17 are respectively connected with a sludge storage tank 22 through pipelines, and the sludge storage tank 22 is sequentially connected with a plate-and-frame filter press 23, a filtrate tank 24 and a fluorine-containing wastewater temporary storage tank 8 through pipelines.
A pH adjusting unit is arranged in the adjusting tank 1, and a bactericide dosing unit and a coagulant dosing unit are connected on a pipeline between the adjusting tank 1 and the multi-media filter 2.
The releasing pool 21 is connected with the fluorine-containing wastewater temporary storage pool 8 through a pipeline, the water outlet of the fluorine-removing resin tower 20 is connected with the releasing pool 21 through a pipeline, a pH adjusting unit and a fluorine ion on-line monitor are arranged on the pipeline between the fluorine-removing resin tower 20 and the releasing pool 21, and the concentrated water outlet of the fluorine-removing resin tower 20 is connected with the pipeline between the releasing pool 21 and the fluorine wastewater temporary storage pool 8 through a pipeline.
The device comprises an adjusting tank 1, a first multi-media filter 2, a filter water tank 5, a security filter 6, an RO system 7, a fluorine-containing wastewater temporary storage tank 8, an A reaction tank 9, an A intermediate water tank 13, a B reaction tank 14, a B intermediate water tank 18, a second multi-media filter 19, a discharge tank 21, a fluorine-containing wastewater temporary storage tank 8, a pipeline between a fluorine-removing resin tower 20 and the discharge tank 21, a pipeline between the fluorine-containing wastewater temporary storage tank 8, an A sedimentation tank 12, a sludge storage tank 22, a B sedimentation tank 17, a sludge storage tank 22, a plate-and-frame filter press 23, and a water pump arranged on the pipeline between a filter solution tank 24 and the fluorine-containing wastewater temporary storage tank 8.
As shown in figure 1, the process for deeply treating and recycling the fluorine-containing wastewater in the electronic industry comprises the following steps: after the pH of the fluorine-containing wastewater is adjusted by a pH adjusting tank, the fluorine-containing wastewater is treated by a multi-media filter and an activated carbon filter and then enters a softening resin tower for softening treatment, the treated effluent enters a reverse osmosis system, the permeated effluent returns to a pure water system for recycling, and the concentrated water enters a high-concentration fluorine-containing wastewater treatment system. After the pH value of the high-concentration fluorine-containing wastewater is adjusted, the high-concentration fluorine-containing wastewater enters a primary calcification mixing system, mixed effluent enters a secondary deep fluorine removal treatment system, fluorine in the wastewater is treated to 3-5 mg/L, the water inlet load of fluorine removal resin is further reduced, the fluorine of the treated water is stably less than 1mg/L after the treated water is filtered by a plurality of media and adsorbed by a fluorine removal resin tower, and the standard discharge and the recycling of the fluorine-containing wastewater are realized.
The method comprises the following specific steps:
the first step is as follows: fluorine-containing wastewater adjusting system: and lifting the fluorine-containing wastewater to a fluorine-containing wastewater adjusting tank by a pump to uniform the water quality and water quantity, and adjusting the pH to 7-8.
The second step is that: reverse osmosis filtration system: the effluent of the fluorine-containing wastewater adjusting tank sequentially passes through a multi-media filter, an activated carbon filter and a softening device to remove suspended substances, partial organic matters, calcium, magnesium and other hardness in water. And then the fluorine-containing wastewater (the hardness is less than 1mg/L) treated by the softening device enters an RO system (the recovery rate is more than 70%) after the pH is adjusted, the permeate water of the RO system returns to a front-end pure water system for recycling, and the reverse osmosis concentrated water enters a high-concentration fluorine-containing wastewater first-stage mixing system.
And a pH adjusting unit, a bactericide dosing unit and a coagulant dosing unit are arranged in front of the multi-media filter. Before flowing into the multi-media filter, the fluorine-containing wastewater is adjusted to be neutral in pH value, and after a coagulant is added, the fluorine-containing wastewater flows into the multi-media filter, and then the fluorine-containing wastewater filtered by the multi-media filter flows into the activated carbon filter.
The third step: high concentration fluorine-containing waste water first-stage chemical mixing system: the reverse osmosis concentrated water is concentrated high-concentration fluorine-containing wastewater, a single type of fluorine removal agent is added after the pH value is adjusted to be 7-9, the full reaction is carried out for 20-30 min, calcium chloride and fluoride ions in the wastewater form calcium fluoride precipitate, polyacrylamide is added for reaction for 0.25h, and effluent (the concentration of fluorine in water is 15-20 mg/L) enters a secondary deep fluorine removal system of the high-concentration fluorine-containing wastewater after flocculation precipitation is carried out for 2-3 h.
The single type of fluorine removal agent is a simple inorganic substance, and specifically, a calcium chloride solution with a mass concentration of 30% or a calcium hydroxide solution with a mass concentration of 10% is preferred.
The addition amount of the calcium chloride is that the molar ratio Ca/F is 0.6-0.65, and the concentration of the polyacrylamide is 3 mg/L.
The fourth step: high concentration fluorine waste water second grade degree of depth defluorination system: adding a composite type deep fluorine removal agent (200-500 mg/L), reacting for 0.5h, adjusting the pH of the effluent to 6-7, adding polyacrylamide to react for 0.25h, performing flocculation precipitation for 2-3 h, and then enabling the effluent to enter a fluorine removal resin system, wherein the concentration of fluorine in the wastewater is 3-6 mg/L, and compared with the conventional calcium-adding fluorine removal process (only removing fluorine in the wastewater to 10-20 mg/L), the dosage of the fluorine removal resin can be greatly reduced.
The compound type deep fluorine removal agent is prepared from polyaluminium chloride (50%) (the purity is defined as Al)2O3The content of the active aluminum oxide is more than or equal to 28 percent, the content of the active aluminum oxide is more than or equal to 20 percent, the content of the calcium fluoride is more than or equal to 5 percent, the content of the polymeric ferric chloride is more than or equal to 20 percent, the content of the modified molecular sieve is more than or equal to 5 percent, and the like. The fluorine in the water is removed by the high affinity and adsorption of the aluminum to the fluorine ions.
The concentration of the polyacrylamide is 3 mg/L.
The fifth step: defluorination resin system: the effluent of the high-concentration fluorine-containing wastewater two-stage deep fluorine removal system enters a multi-media filter to remove colloids and suspended substances in water. The filtered water enters a defluorination resin tower for advanced treatment, the aluminum-containing groups of the resin are used for adsorbing fluoride ions in the water, the effluent of the resin can be stably treated to be below 1mg/L, and the concentrated water of the resin returns to a high-concentration fluorine-containing wastewater first-stage mixing system for continuous treatment.
The effluent of the defluorination resin tower is provided with a pH adjusting unit and a fluorine ion online monitor, the pH value of the effluent treated by the defluorination resin adsorption tower is adjusted to 6.5-8.5, and the effluent reaching the standard flows into a drainage pool (a final drainage monitoring tank); if the quality of the discharged water is unqualified, the unqualified water flows back to the front end (the fluorine-containing wastewater temporary storage tank) through the switching of a valve and a pipeline.
And a sixth step: sludge treatment: guiding the sediment in the previous step (in a sedimentation tank) into a filter press for dehydration treatment, returning the pressed water to a high-concentration fluorine-containing wastewater first-stage mixing system for treatment, and carrying out outsourcing treatment on the generated mud cakes.
Example 1
Water quality of fluorine-containing wastewater of a certain semiconductor factory: pH of 1.5-3, F of 300-400 mg/L, TDS of 250-300 mg/L, and wastewater flow of 3000m3And d. The implementation of the embodiment comprises the following steps:
the first step is as follows: adjusting the pH value to 7, entering a multi-media filter and an activated carbon filter, and arranging a pH adjusting and sterilizing agent adding unit and a coagulant adding unit in front of the multi-layer filter. And (3) the fluorine-containing wastewater filtered by the activated carbon filter flows into a softening resin tower, and the hardness of the fluorine-containing wastewater is less than 1 mg/L.
The second step is that: filtered water enters an RO system, the final water yield is 77-78%, concentrated water generated by RO enters a high-concentration fluorine-containing wastewater treatment system, and RO outlet water is recycled to a front-end pure water system.
The third step: and (2) adjusting the pH value of the reverse osmosis concentrated water to 8, then feeding the reverse osmosis concentrated water into a primary calcification mixing system, sequentially adding calcium chloride (Ca/F is 0.6, the molar ratio) and polyacrylamide (3mg/L), reacting for 0.5h and 0.25h respectively, precipitating for 2h, then feeding the first-stage mixed water into a secondary deep defluorination system, wherein the fluorine content of the first-stage mixed water is 18-20 mg/L.
The fourth step: directly adding a compound type deep defluorinating agent (300mg/L) into the first-stage calcified mixed effluent, reacting for 0.5h, adjusting the pH value to 7, adding polyacrylamide (3mg/L, 0.25h), precipitating for 2h, then enabling the second-stage mixed effluent to enter a defluorinating resin system, and enabling the fluorine content of the second-stage mixed effluent to be 5-6 mg/L.
The fifth step: the effluent treated by the defluorination resin adsorption tower is mixed by a pipeline mixer, the pH value is adjusted to be 7, the effluent reaching the standard flows into a final effluent monitoring tank, and the fluorine content of the effluent is 0.2 mg/L.
Example 2
The water quality of the fluorine-containing wastewater of a certain panel factory is as follows: pH of 2-3, F of 200-300 mg/L, TDS of 500-600 mg/L, and wastewater flow rate of 2000m3And d. The implementation of the embodiment comprises the following steps:
the first step is as follows: adjusting the pH value to 7, feeding the wastewater into a multi-media filter and an activated carbon filter, arranging a pH adjusting and sterilizing agent feeding unit and a coagulant agent feeding unit in front of a multi-layer filter, and then feeding the fluorine-containing wastewater filtered by the activated carbon filter into a softening resin tower, wherein the hardness of the fluorine-containing wastewater is less than 1 mg/L.
The second step is that: and (4) filtering the effluent to enter an RO system, wherein the final water yield is 75%, the concentrated water generated by RO enters a high-concentration fluorine-containing wastewater treatment system, and the RO effluent is recycled to a front-end pure water system.
The third step: after the pH value of the reverse osmosis concentrated water is adjusted to 7, the reverse osmosis concentrated water enters a first-stage calcium adding mixing system, calcium chloride (Ca/F is 0.65, the molar ratio of the Ca/F to the calcium chloride) and polyacrylamide (3mg/L) are sequentially added to react for 0.5h and 0.25h respectively, after 2h of precipitation, the first-stage mixed water enters a second-stage deep defluorination system, and the fluorine content of the first-stage mixed water is about 15 mg/L.
The fourth step: directly adding a compound type deep defluorinating agent (200mg/L) into the first-stage calcified mixed water, reacting for 0.5h, adjusting the pH value to 6.5, adding polyacrylamide (3mg/L, 0.25h), precipitating for 2h, then enabling the second-stage mixed water to enter a defluorinating resin system, and enabling the fluorine content of the second-stage mixed water to be about 5 mg/L.
The fifth step: the effluent treated by the defluorination resin adsorption tower is mixed by a pipeline mixer, the pH value is adjusted to be 7, the effluent reaching the standard flows into a final effluent monitoring tank, and the fluorine content of the effluent is about 0.15 mg/L.
Comparative example
Water quality of fluorine-containing wastewater of a certain semiconductor factory: pH of 2-3, F of 300-400 mg/L, TDS of 300mg/L, and wastewater flow rate of 1000m3And d. The implementation of the embodiment comprises the following steps:
the first step is as follows: and (2) adjusting the pH value of the fluorine-containing wastewater to 8, then feeding the fluorine-containing wastewater into a primary calcium adding mixing system, sequentially adding calcium chloride (Ca/F is 0.65, the molar ratio) and polyacrylamide (3mg/L), reacting for 0.5h and 0.25h respectively, precipitating for 2h, and then enabling the primarily mixed effluent to enter a secondary deep fluorine removal system, wherein the fluorine content of the primarily mixed effluent is 15-20 mg/L.
The second step is that: directly adding a compound type deep fluorine removal agent (2000mg/L) into the first-stage calcified mixed water, adjusting the pH to 7 after reacting for 0.5h, adding polyacrylamide (3mg/L, 0.25h), precipitating for 2h, adjusting the pH of the mixed water to 7, and discharging the mixed water after reaching the standard, wherein the fluorine in the water is 0.58 mg/L.
The third step: and (3) guiding the precipitates in the primary and secondary sedimentation tanks into a filter press for dehydration treatment, returning the pressed water to the primary mixing system for treatment, and treating the generated mud cakes.
The technological process of 'first-stage calcium adding and second-stage fluorine removing agent adding' is adopted, the adding amount of the fluorine removing agent is 2.0kg/d, and the operating cost is about 11.77 yuan/ton of water. Compared with the process, the dosage of the medicament is 0.4kg/d, and the dosage is reduced by 80 percent; the operating cost is about 4.07 yuan/ton of water, and the equivalent ratio is reduced by 65.4%; meanwhile, the average water yield of the reuse water is 72-74%, and the fresh water consumption can be greatly reduced.
For those skilled in the art, it will be appreciated that, in light of the above disclosure and the above detailed description, certain modifications may be made without departing from the spirit or scope of the invention as defined in the appended claims, and all changes that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
Claims (12)
1. The advanced treatment and recycling process of fluorine-containing wastewater in the electronic industry is characterized by comprising the following process steps:
the first step is as follows: fluorine-containing wastewater adjusting system: lifting the fluorine-containing wastewater to a fluorine-containing wastewater adjusting tank by a pump to uniform the water quality and water quantity, and adjusting the pH to 7-8;
the second step is that: reverse osmosis filtration system: the effluent of the fluorine-containing wastewater adjusting tank sequentially passes through a multi-media filter, an activated carbon filter and a softening device to remove suspended substances, partial organic matters and calcium and magnesium hardness in water, then the fluorine-containing wastewater with the hardness of less than 1mg/L is treated by the softening device, the fluorine-containing wastewater enters an RO system after the pH is adjusted, the recovery rate of the RO system is more than 70 percent, the permeate effluent of the RO system returns to a front-end pure water system for recycling, and the reverse osmosis concentrated water enters a high-concentration fluorine-containing wastewater first-stage mixing system;
the third step: high concentration fluorine-containing waste water first-stage chemical mixing system: the reverse osmosis concentrated water is concentrated high-concentration fluorine-containing wastewater, after the pH is adjusted to be 7-9, a single type of fluorine removal agent is added, the full reaction is carried out for 20-30 min, calcium fluoride precipitate is formed with fluorine ions in the wastewater, polyacrylamide is added for reaction for 0.25h, water is discharged after flocculation precipitation is carried out for 2-3 h, the concentration of fluorine in the water is 15-20 mg/L, and the water enters a secondary deep fluorine removal system for the high-concentration fluorine-containing wastewater;
the fourth step: high concentration fluorine waste water second grade degree of depth defluorination system: adding a compound type deep fluorine removal agent, reacting for 0.5h, adjusting the pH of the effluent to 6-7, adding polyacrylamide, reacting for 0.25h, performing flocculation precipitation for 2-3 h, and allowing the effluent to enter a fluorine removal resin system, wherein the fluorine concentration in the wastewater is 3-6 mg/L;
the fifth step: defluorination resin system: the effluent of the secondary deep fluorine removal system of the high-concentration fluorine-containing wastewater enters a multi-medium filter to remove colloids and suspended substances in water, the filtered effluent enters a fluorine removal resin tower for deep treatment, aluminum-containing groups of resin are used for adsorbing fluorine ions in water, the effluent of the resin is stably treated to be below 1mg/L, and the concentrated resin water returns to the primary mixing system of the high-concentration fluorine-containing wastewater for continuous treatment.
2. The advanced treatment and recycling process of fluorine-containing wastewater in the electronic industry as claimed in claim 1, wherein in the reverse osmosis filtration system of the second step, a pH adjusting unit, a bactericide adding unit and a coagulant adding unit are arranged in front of the multi-media filter, the pH of the fluorine-containing wastewater is adjusted to be neutral before the fluorine-containing wastewater flows into the multi-media filter, the coagulant is added, the fluorine-containing wastewater flows into the multi-media filter, and then the fluorine-containing wastewater filtered by the multi-media filter flows into the activated carbon filter.
3. The advanced treatment and recycling process of fluorine-containing wastewater in the electronic industry as claimed in claim 1, wherein in the first-stage mixed system of high-concentration fluorine-containing wastewater in the third step, the single type of fluorine removal agent is calcium chloride solution with mass concentration of 30% or calcium hydroxide solution with mass concentration of 10%.
4. The advanced treatment and recycling process of fluorine-containing wastewater in the electronic industry of claim 3, wherein the addition amount of calcium chloride is 0.6-0.65 molar ratio Ca/F, and the concentration of polyacrylamide is 3 mg/L.
5. The advanced treatment and recycling process of fluorine-containing wastewater in the electronic industry of claim 1, wherein in the fourth step of the second-stage advanced fluorine removal system of high-concentration fluorine-containing wastewater, the concentration of the composite advanced fluorine removal agent is 200-500 mg/L, and the concentration of polyacrylamide is 3 mg/L.
6. The advanced treatment and recycling process of fluorine-containing wastewater in the electronic industry as claimed in claim 5, wherein the compound advanced fluorine removal agent is prepared from polyaluminium chloride, activated alumina, calcium fluoride, polyferric chloride and a modified molecular sieve, and the pH value is 1-3.
7. The advanced treatment and recycling process of fluorine-containing wastewater in the electronic industry of claim 6, wherein the mass ratio of the polyaluminium chloride, the activated alumina, the calcium fluoride, the polyferric chloride and the modified molecular sieve is 50: 20: 5: 20: 5.
8. the advanced treatment and recycle process of fluorine-containing wastewater in electronic industry as claimed in claim 7, wherein the purity of the polyaluminium chloride is defined as Al2O3The content is more than or equal to 28 percent.
9. The advanced treatment and recycling process of fluorine-containing wastewater in the electronic industry as claimed in claim 5, wherein in the fifth step of the fluorine-removing resin system, the effluent of the fluorine-removing resin tower is provided with a pH adjusting unit and a fluorine ion online monitor, the pH of the effluent treated by the fluorine-removing resin tower is adjusted to 6.5-8.5, and the effluent reaching the standard flows into a drainage pool; if the quality of the discharged water is unqualified, the unqualified water is refluxed to a high-concentration fluorine-containing wastewater first-stage mixing system for treatment by switching a valve and a pipeline.
10. The advanced treatment and recycling process of fluorine-containing wastewater in the electronic industry according to any one of claims 1 to 9, further comprising sludge treatment: and (3) guiding precipitates generated by the high-concentration fluorine-containing wastewater first-stage mixing system and the high-concentration fluorine-containing wastewater second-stage deep defluorination system into a filter press for dehydration treatment, returning the squeezed water to the high-concentration fluorine-containing wastewater first-stage mixing system for treatment, and carrying out external treatment on the generated mud cakes.
11. The utility model provides an electron trade fluorine-containing waste water advanced treatment and recycling system, a serial communication port, include equalizing basin (1) that connects gradually through the pipeline, first many medium filter (2), activated carbon filter (3), softening installation (4), filter tank (5), safety filter ware (6), RO system (7), fluorine-containing waste water temporary storage pond (8), high concentration fluorine-containing waste water one-level system of mixing, high concentration fluorine-containing waste water second grade degree of depth defluorination system, many medium filter of second (19), defluorination resin tower (20) and drainage pond (21), equalizing basin (1) is connected fluorine-containing waste water and is advanced the pipe, drainage pond (21) are connected up to standard delivery pipe.
12. The advanced treatment and recycling system for fluorine-containing wastewater in the electronic industry as claimed in claim 11, wherein the high-concentration fluorine-containing wastewater first-stage mixing system comprises a reaction tank A (9), a coagulation tank A (10), a flocculation tank A (11), a sedimentation tank A (12) and an intermediate water tank A (13) which are connected in sequence, and the high-concentration fluorine-containing wastewater second-stage advanced defluorination system comprises a reaction tank B (14), a pH adjusting tank (15), a flocculation tank B (16), a sedimentation tank B (17) and an intermediate water tank B (18) which are connected in sequence; the A sedimentation tank (12) and the B sedimentation tank (17) are respectively connected with a sludge storage tank (22) through pipelines, and the sludge storage tank (22) is sequentially connected with a plate-and-frame filter press (23), a filtrate tank (24) and a fluorine-containing wastewater temporary storage tank (8) through pipelines; a pH adjusting unit is arranged in the adjusting tank (1), and a bactericide dosing unit and a coagulant dosing unit are connected on a pipeline between the adjusting tank (1) and the multi-medium filter (2); the discharging pool (21) is connected with the fluorine-containing wastewater temporary storage pool (8) through a pipeline, a water outlet of the defluorination resin tower (20) is connected with the discharging pool (21) through a pipeline, a pH adjusting unit and a fluorine ion online monitor are arranged on the pipeline between the defluorination resin tower (20) and the discharging pool (21), and a concentrated water outlet of the defluorination resin tower (20) is connected with the pipeline between the discharging pool (21) and the fluorine wastewater temporary storage pool (8) through a pipeline.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010247900.1A CN111268830A (en) | 2020-04-01 | 2020-04-01 | System and process for advanced treatment and recycling of fluorine-containing wastewater in electronic industry |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010247900.1A CN111268830A (en) | 2020-04-01 | 2020-04-01 | System and process for advanced treatment and recycling of fluorine-containing wastewater in electronic industry |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN111268830A true CN111268830A (en) | 2020-06-12 |
Family
ID=70996220
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010247900.1A Pending CN111268830A (en) | 2020-04-01 | 2020-04-01 | System and process for advanced treatment and recycling of fluorine-containing wastewater in electronic industry |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN111268830A (en) |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112811669A (en) * | 2021-01-28 | 2021-05-18 | 天津市联合环保工程设计有限公司 | Fluorine-containing industrial wastewater treatment system and treatment method thereof |
| CN113087040A (en) * | 2021-04-20 | 2021-07-09 | 山西国际电力技术咨询有限公司 | Novel defluorinating agent and fluorine-containing waste liquid treatment process |
| CN113620477A (en) * | 2021-09-13 | 2021-11-09 | 宝武水务科技有限公司 | Defluorination device and method for high-salinity wastewater |
| CN114105365A (en) * | 2021-12-02 | 2022-03-01 | 苏州新能环境技术股份有限公司 | Photovoltaic production wastewater recycling treatment process |
| CN114436448A (en) * | 2022-02-21 | 2022-05-06 | 辽宁博创环保技术有限公司 | Method for producing calcium fluoride by using high-fluorine-content industrial wastewater |
| CN115340221A (en) * | 2022-09-14 | 2022-11-15 | 深圳市环境科学研究院 | Deep defluorination treatment process and recycling system |
| CN115771972A (en) * | 2022-12-16 | 2023-03-10 | 内蒙古大全新能源有限公司 | Treatment method and treatment system for fluorine-containing wastewater discharge |
-
2020
- 2020-04-01 CN CN202010247900.1A patent/CN111268830A/en active Pending
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112811669A (en) * | 2021-01-28 | 2021-05-18 | 天津市联合环保工程设计有限公司 | Fluorine-containing industrial wastewater treatment system and treatment method thereof |
| CN113087040A (en) * | 2021-04-20 | 2021-07-09 | 山西国际电力技术咨询有限公司 | Novel defluorinating agent and fluorine-containing waste liquid treatment process |
| CN113620477A (en) * | 2021-09-13 | 2021-11-09 | 宝武水务科技有限公司 | Defluorination device and method for high-salinity wastewater |
| CN114105365A (en) * | 2021-12-02 | 2022-03-01 | 苏州新能环境技术股份有限公司 | Photovoltaic production wastewater recycling treatment process |
| CN114436448A (en) * | 2022-02-21 | 2022-05-06 | 辽宁博创环保技术有限公司 | Method for producing calcium fluoride by using high-fluorine-content industrial wastewater |
| CN115340221A (en) * | 2022-09-14 | 2022-11-15 | 深圳市环境科学研究院 | Deep defluorination treatment process and recycling system |
| CN115771972A (en) * | 2022-12-16 | 2023-03-10 | 内蒙古大全新能源有限公司 | Treatment method and treatment system for fluorine-containing wastewater discharge |
| CN115771972B (en) * | 2022-12-16 | 2023-09-22 | 内蒙古大全新能源有限公司 | Treatment method and treatment system for fluorine-containing wastewater discharge |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111268830A (en) | System and process for advanced treatment and recycling of fluorine-containing wastewater in electronic industry | |
| CN106430773B (en) | Treatment method of high-salt-content industrial wastewater with different ion concentrations | |
| CN103288236B (en) | Treatment method for salt-containing wastewater | |
| CN110240342B (en) | Device and method for treating landfill leachate in arid and cold regions | |
| CN112794500B (en) | Coking wastewater strong brine near-zero emission treatment system and treatment method thereof | |
| CN105347574A (en) | Fluoride removal method of graphite purification waste water and processing system | |
| CN113562924A (en) | Treatment system and method for resource utilization of high-salinity wastewater in ferrous metallurgy | |
| CN111170544A (en) | Zero discharge system and method for pretreatment wastewater of active coke desulfurization and denitrification and salt preparation from rich gas | |
| CN111995155A (en) | Method for recycling ammoniacal nitrogen-containing acidic wastewater | |
| CN103204595A (en) | Advanced treatment method for coking phenol-cyanogen wastewater | |
| CN111392984A (en) | Advanced treatment system and method for supplementing water by using urban reclaimed water as circulating water of power plant | |
| CN111777220A (en) | Novel softening treatment method for high-salinity and high-permanent-hardness wastewater | |
| CN114906989A (en) | Coal chemical industry waste water salt-separation zero-emission process system and treatment method | |
| CN101628771A (en) | Method with zero discharge of waste water | |
| CN105481160B (en) | Method and device for preparing industrial salt by strong brine with zero discharge | |
| CN112573720A (en) | Thermal power plant desulfurization wastewater zero-discharge system and method | |
| CN111115661A (en) | Nitric acid wastewater treatment system and method | |
| CN103253832B (en) | Reusing treatment method of coking wastewater | |
| CN212127808U (en) | Advanced treatment and recycling system for fluorine-containing wastewater in electronic industry | |
| CN212425805U (en) | Treatment recycling system for electric demisting wastewater and/or electric precipitation wastewater | |
| CN210915710U (en) | Zero-emission and recycling treatment system for coal coking high-salinity wastewater | |
| CN210419644U (en) | Contain clean system of salt organic waste water | |
| CN212025096U (en) | Wastewater treatment system | |
| CN113277653A (en) | Desulfurization wastewater treatment system and method | |
| CN112939368A (en) | Circulating water sewage treatment and recycling method with high desalting rate |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |