Radioactive medical waste liquid purification treatment modular system and purification treatment method thereof

Abstract

The invention provides a radioactive medical waste liquid purification treatment modular system and method, and the system comprises waste liquid collection equipment, a solid-liquid separation module, a biochemical reaction module, a membrane separation module, an ion exchange module and an online monitoring device which are sequentially connected through pipelines, the modules can be used in a series-parallel combination manner according to the use requirements of users and the parameters of waste liquid source items, so as to meet different use requirements. The waste liquid collection equipment, the solid-liquid separation module, the biochemical reaction module and the ion exchange module are connected with the gas filter and the industrial dust collector through exhaust pipelines; the ion exchange module is connected with the movable suction device, and the waste adsorption material in the ion exchange module is pumped out and then stored in the waste steel barrel. According to the radioactive medical waste liquid purification treatment modular system and the purification treatment method thereof, few reagents are added, the reaction conditions are simple, the purification effect is good, and the treatment efficiency is high.

Description

Technical Field

[0001] The present invention relates to the technical field of nuclear medical radioactive waste treatment, and in particular to a modular system for purifying radioactive medical waste liquid and a purification method thereof. Background Art

[0002] A certain amount of radioactive waste liquid is generated during the diagnosis and treatment of nuclear medicine isotopes. The sources of the waste liquid mainly include the flushing liquid of radioactively contaminated instruments, the flushing liquid of patients' hand washing and showering, and the patients' excrement. At present, the main process for waste liquid purification is storage decay, that is, the waste liquid is stored in a decay pool for a certain period of time, and further treatment is carried out when the radioactive nuclides in the waste liquid naturally decay to an environmentally acceptable concentration.

[0003] With the rapid development of the isotope industry, a larger amount and more types of medical isotopes will be used in clinical diagnosis and treatment. At the same time, a larger amount of waste liquid containing more types of radioactive nuclides will be generated. Therefore, the current storage decay process is difficult to meet the future demand for the purification of radioactive waste liquid. Its limitations are mainly reflected in: (1) the expansion cost of the storage decay pool is high, the construction period is long, and the land resources are tight; (2) there is a certain risk of leakage when a large amount of waste liquid is stored for a long time; (3) storage decay is difficult to purify waste liquid containing long half-life nuclides.

[0004] Therefore, in order to meet the future purification and treatment needs of nuclear medical radioactive waste liquid and solve the limitations of traditional storage decay processes, a new radioactive medical waste liquid purification treatment device and purification treatment method are urgently needed, which has the advantages of being able to adapt to radioactive waste liquid with complex components, good purification effects on various typical radionuclides, simple reaction conditions, and less reagents added. It can also significantly improve the purification effect and treatment efficiency of radioactive medical waste liquid and achieve safe treatment and volume reduction of radioactive nuclear medical waste. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a modular system for purifying radioactive medical waste liquid and a purification method thereof, which has the advantages of less added reagents, simple reaction conditions, good purification effect and high treatment efficiency.

[0006] In order to solve the above technical problems, the present invention provides a modular system for purifying radioactive medical waste liquid, comprising a waste liquid collection device, a solid-liquid separation module connected to the waste liquid collection device by a pipeline, a biochemical reaction module connected to the solid-liquid separation module by a pipeline, a membrane separation module connected to the biochemical reaction module by a pipeline, an ion exchange module connected to the membrane separation module by a pipeline, and an online monitoring device connected to the ion exchange module by a pipeline, wherein the online monitoring device is connected to a purified water collection tank;

[0007] The waste liquid collection device, solid-liquid separation module, biochemical reaction module and ion exchange module are connected to a gas filter and an industrial vacuum cleaner through an exhaust pipe;

[0008] The ion exchange module is connected to a mobile suction device, and the waste adsorption material in the ion exchange module is pumped out and stored in a waste steel drum;

[0009] Both the filter element of the solid-liquid separation module and the membrane component of the membrane separation module are designed with an overall quick-release structure that can be integrally loaded, unloaded and replaced by a manipulator, and the replaced waste membrane components and filter elements are stored in a waste steel drum;

[0010] According to the user's usage requirements and waste liquid source item parameters, the modules can be used in series and parallel combinations to meet different usage requirements.

[0011] Further, the waste liquid collection device is connected to the biochemical reaction module by a pipeline, the solid-liquid separation module is connected to the membrane separation module by a pipeline, the biochemical reaction module is connected to the ion exchange module by a pipeline, the membrane separation module is connected to an on-line monitoring device by a pipeline, and the on-line monitoring device is connected to the waste liquid collection device by a pipeline.

[0012] Further, the start and stop of valves and pump-type active equipment on the connecting pipelines of the waste liquid collection device, solid-liquid separation module, biochemical reaction module, membrane separation module, ion exchange module, on-line monitoring device and purified water collection tank can be remotely and automatically controlled.

[0013] Further, the solid-liquid separation module includes a spiral centrifuge, an activated carbon filter and a bag filter connected in series in sequence, and the bag filter uses a filter element with a filtration accuracy of 45μm.

[0014] Further, the biochemical reaction module uses a sequencing batch reactor, and the sequencing batch reactor is loaded with a composite substrate material formed by doping activated sludge for culturing microorganisms with carbon nanotubes.

[0015] Further, the membrane separation module includes an ultrafiltration device and a reverse osmosis device connected in series. The cut-off particle size of the ultrafiltration membrane of the ultrafiltration device is 0.001 - 0.1μm, and the cut-off particle size of the reverse osmosis membrane of the reverse osmosis device is 1×10 -10 m - 10×10 -10 m.

[0016] Further, the ion exchange module adopts a structural mode in which an anion exchange resin column, a cation exchange resin column and a mixed anion and cation exchange column are connected in series.

[0017] Further, the ion exchange column can be filled with inorganic adsorption materials including activated carbon, molecular sieve, graphene, zirconium phosphate and collagen fiber.

[0018] The present invention also provides a method for purifying and treating radioactive medical waste liquid, comprising the following steps:

[0019] Removing solid suspended matters in the waste liquid through a solid-liquid separation module by solid-liquid separation of the waste liquid;

[0020] Biodegrading chemical pollutants in the waste liquid through a biochemical reaction module;

[0021] Removing chemical pollutants, salts and radionuclides in the waste liquid through a membrane separation module;

[0022] Removing radionuclides in the waste liquid through an ion exchange module;

[0023] Monitoring the purified waste liquid through an on-line monitoring device, and discharging it from a purified water collection tank after reaching the standard, otherwise returning it to a waste liquid collection tank for continuous purification;

[0024] Exhaust gas and aerosol generated during the purification process enter a gas filter and an industrial vacuum cleaner through an exhaust pipe for purification treatment;

[0025] Waste adsorption materials of the ion exchange module during the purification process are extracted by a mobile suction device and stored in a waste steel barrel;

[0026] Waste filter elements of the solid-liquid separation module and waste membrane components of the membrane separation module during the purification process are integrally replaced by a manipulator and stored in a waste steel barrel.

[0027] Further, the microorganisms cultured in the biochemical reaction module can decompose chemical pollutants in the waste liquid, including ammonia nitrogen organic compounds, urea, ammonium phosphate, creatinine, aerosol and metal chelates.

[0028] A modular system for purifying and treating radioactive medical waste liquid and a purification and treatment method provided by the present invention pass radioactive medical waste liquid through a solid-liquid separation module, a biochemical reaction module, a membrane separation module and an ion exchange module in sequence to remove solid suspended matters, chemical pollutants, salts and radionuclides in the radioactive medical waste liquid respectively, and then on-line monitor the purified waste liquid through an on-line monitoring device. If the treated waste liquid meets the discharge limit requirements of national standards for various pollutants and radionuclides, it is directly discharged from the purified water collection tank. If the waste liquid still does not meet the discharge limit requirements of national standards for various pollutants and radionuclides, the waste liquid returns to the purification treatment system for continuous purification.

[0029] Compared with the traditional technical methods for storing and decaying radioactive medical waste liquid, the modular system for purifying and treating radioactive medical waste liquid and the purification and treatment method thereof provided by the present invention integrate the functions of waste liquid collection, purification and treatment, and online monitoring, which can not only reduce the purification and treatment cycle of the waste liquid and have the advantage of timeliness, but also reduce the risk of leakage of the waste liquid during long-term storage. At the same time, the device of the present invention is integrated in a container-type box body, occupies a small space, can greatly reduce the storage capacity of radioactive medical waste liquid, can save a lot of space, has more obvious economic advantages, and has good application prospects in the field of nuclear medicine radioactive waste treatment.

[0030] In addition, the modular system for purifying radioactive medical waste liquid and the purification method thereof provided by the present invention adopt a modular design. According to different water quality conditions and treatment requirements, the modules can be connected in series and parallel and quickly assembled, which can improve the purification efficiency of the waste liquid. The purification treatment capacity can reach 0.4-1.0m 3 / h, the radioactivity index of the purified water is total β<10Bq / L, which can meet the requirements of the relevant national standards for medical waste liquid discharge.

[0031] At the same time, the modular system for purifying radioactive medical waste liquid and its purification method provided by the present invention, the process exhaled gas and aerosol and other waste gases generated in the purification system during the purification process enter the high-efficiency gas filter and industrial vacuum cleaner and other equipment through the exhaust pipe for purification, and are discharged after reaching the standard, thereby reducing air pollution and being green and environmentally friendly. Moreover, during the purification process, the failed waste adsorption materials in the ion exchange module are extracted by the mobile suction device controlled by artificial remote intelligent control and stored in the waste steel barrel, and the failed waste filter element in the solid-liquid separation module and the failed waste membrane assembly in the membrane separation module are replaced as a whole by the manipulator controlled by artificial remote intelligent control and stored in the waste steel barrel, so that the generated secondary waste is properly and safely disposed of, the radiation protection of the staff is optimized, and the personal safety and health of the staff are guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A flowchart of a modular system for purifying radioactive medical waste liquid provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0033] See also Figure 1 A modular system for purifying and treating radioactive medical waste liquid provided by an embodiment of the present invention includes a waste liquid collection device 1, a solid-liquid separation module 2 connected to the waste liquid collection device 1 by a pipeline, a biochemical reaction module 3 connected to the solid-liquid separation module 2 by a pipeline, a membrane separation module 4 connected to the biochemical reaction module 3 by a pipeline, an ion exchange module 5 connected to the membrane separation module 4 by a pipeline, and an online monitoring device 6 connected to the ion exchange module 5 by a pipeline.

[0034] When the radioactive medical waste liquid stored in the waste liquid collection device 1 passes through the solid-liquid separation module 2, the biochemical reaction module 3, the membrane separation module 4, and the ion exchange module 5 in sequence, solid suspended substances, chemical pollutants, salts, and radionuclides in the radioactive medical waste liquid can be removed respectively. Then, the waste liquid after purification treatment is monitored online by the online monitoring device 6. If the treated waste liquid meets the discharge limit requirements of the national standards for various pollutants and radionuclides, it is directly stored and discharged into the purified water collection tank. If the waste liquid still does not meet the discharge limit requirements of the national standards for various pollutants and radionuclides, the waste liquid returns to the waste liquid collection device 1 to continue the purification treatment by the purification treatment system.

[0035] Compared with the traditional technical method of storing and decaying radioactive medical waste liquid, the modular system for purifying and treating radioactive medical waste liquid and its purification and treatment method provided by the present invention integrate the functions of waste liquid collection, purification treatment, and online monitoring. It can not only reduce the purification treatment cycle of the waste liquid, having the advantage of timeliness, but also reduce the risk of leakage that is likely to occur during the long-term storage of the waste liquid. At the same time, the device of the present invention is integrated in a container-type box, occupying a small space, and can greatly reduce the storage capacity of radioactive medical waste liquid, saving a large amount of space, having more obvious economic advantages, and having good application prospects in the field of nuclear medicine radioactive waste treatment.

[0036] Among them, the waste liquid collection device 1 is also connected to the biochemical reaction module 3 through a pipeline, the solid-liquid separation module 2 is also connected to the membrane separation module 4 through a pipeline, the biochemical reaction module 3 is also connected to the ion exchange module 5 through a pipeline, the membrane separation module 4 is also connected to the online monitoring device 6 directly through a pipeline, and the online monitoring device 6 is also connected to the waste liquid collection device 1 directly through a pipeline.

[0037] Moreover, valves and pump-type active devices (not shown in the figure) are respectively arranged on the connecting pipelines between the above-mentioned waste liquid collection device 1, solid-liquid separation module 2, biochemical reaction module 3, membrane separation module 4, ion exchange module 5, and online monitoring device 6, and the start and stop of these valves and pump-type active devices are respectively controlled by remote automation operation.

[0038] In the actual waste liquid purification process, according to the water quality parameters of radioactive medical waste liquid and the purification requirements, the number, sequence and combination mode of each wastewater treatment process module can be determined. Then, through remote automated operation, the start and stop of valves and pump-type active devices on the pipelines connecting the waste liquid collection device 1, solid-liquid separation module 2, biochemical reaction module 3, membrane separation module 4, ion exchange module 5, and on-line monitoring device 6 can be controlled respectively. Select several of these process devices for series-parallel connection and rapid assembly to conduct targeted purification treatment on the waste liquid. In this way, not only can the waste liquid achieve long-distance fully automated operation during the treatment process, with certain flexibility in process operation, but also the treatment capacity and purification coefficient can be adjusted, and targeted regulation can be carried out for some typical usage scenarios and requirements, which can greatly improve the purification efficiency of radioactive medical waste liquid.

[0039] In this way, the modular system for purifying radioactive medical waste liquid and its purification method provided by the present invention adopt modular design. According to different water quality conditions and treatment requirements, module series-parallel connection and rapid assembly can be carried out, which can improve the purification efficiency of the waste liquid, and its purification treatment capacity can reach 0.4 - 1.0 m 3 / h, which can meet the requirements of waste liquid discharge limits.

[0040] Meanwhile, in order to reduce air pollution to the environment, the waste liquid collection device 1, solid-liquid separation module 2, biochemical reaction module 3, and ion exchange module 4 are respectively connected to a gas filter and an industrial vacuum cleaner through exhaust pipes. During the purification process of the waste liquid, process exhaust gases such as process exhaust air and aerosols generated in the purification system can enter equipment such as high-efficiency gas filters and industrial vacuum cleaners through the exhaust pipes for purification treatment, and are discharged after reaching the standard, thereby reducing air pollution and being environmentally friendly.

[0041] Moreover, the ion exchange module 4 is connected to a mobile suction device. When the adsorption material in the ion exchange module 4 fails due to long-term use, these waste adsorption materials can be pumped out through the mobile suction device and stored in a waste steel drum, and then new adsorption materials are added to the ion exchange module 4. In addition, the filter element of the solid-liquid separation module 2 and the membrane module of the membrane separation module 5 are both designed as integral quick-disassembly types that can be integrally disassembled and replaced. After the filter element of the solid-liquid separation module 2 and the membrane module of the membrane separation module 5 fail due to long-term use, the filter element of the solid-liquid separation module 2 and the membrane module of the membrane separation module 5 can be conveniently disassembled and replaced by the grasping tool of a portable manipulator, and the replaced waste membrane module and filter element are stored in a waste steel drum.

[0042] By using portable suction and grasping tools, secondary wastes such as waste adsorption materials, waste components, and waste filter elements generated in the purification treatment system are suctioned and disassembled, and collected in waste steel drums, which facilitates personnel to operate at a distance, effectively manages the secondary wastes generated in the purification treatment system, and realizes the optimization of personnel radiation protection.

[0043] As a specific embodiment of the present invention, the solid-liquid separation module 2 includes a spiral centrifuge, an activated carbon filter, and a bag filter connected in series in sequence.

[0044] Among them, after the radioactive medical waste liquid in the waste liquid collection device 1 enters the spiral centrifuge of the solid-liquid separation module 2 and passes through the drum of the spiral centrifuge, under the action of the high-speed rotating centrifugal force, solid impurities and suspended matters are deposited on the inner wall of the drum, and the relatively moving spiral blades scrape off the solid impurities and push them to the slag discharge port. The formed clear liquid flows out at the other end of the centrifugal drum and enters the activated carbon filter of the solid-liquid separation module 2. The spiral centrifuge is suitable for the treatment of sewage with complex components, has a large treatment capacity, strong corrosion resistance, high automation degree, is safe and reliable, and the solid-liquid separation rate can reach more than 97%.

[0045] After the clear liquid in the spiral centrifuge enters the activated carbon filter, the activated carbon filter can further adsorb pollutants such as solid suspended matters, microorganisms, heavy metal ions, free chlorine, and organic matters in the waste liquid, and can effectively reduce the COD value in the waste liquid.

[0046] The bag filter is a relatively new type of filtering device. Inside, the filter bag is supported by a metal wire basket. The liquid coming out of the activated carbon filter flows into the bag filter through the inlet, and after being filtered by the filter bag, it flows out through the outlet, and the impurities are intercepted in the filter bag. It can continue to be used after replacing the filter bag. The bag filter can effectively reduce the turbidity of the waste liquid and the COD value in the waste liquid.

[0047] As a specific embodiment of the present invention, the bag filter uses a filter element with a filtration accuracy of 45μm, and the purification rate of the turbidity and COD value of the waste liquid can reach 40%. The bag filter has good sealing performance, is structurally compact, is convenient to install, occupies a small area, has a high filtration accuracy, and the filter bag can be used multiple times after being cleaned, which can reduce the operating cost.

[0048] The present invention uses the solid-liquid separation technology to purify and separate the solid suspended matters in the waste liquid, separates most of the solid suspended matters, and creates favorable conditions for the subsequent biochemical reaction module 3 to further purify the waste liquid by using the biodegradation technology.

[0049] As a specific embodiment of the present invention, the biochemical reaction module 3 adopts a sequencing batch reactor, and the sequencing batch reactor is loaded with a composite substrate material formed by doping carbon nanotubes into the activated sludge for culturing microorganisms.

[0050] Specifically, the biochemical reaction module 3 utilizes biodegradation technology. Through anaerobic reaction, various chemical pollutants in radioactive waste liquid can be efficiently purified, including typical ammonia nitrogen organic compounds, urea, ammonium phosphate, creatinine, aerosol, metal chelates, etc. Due to the advantages of carbon nanotubes such as large specific surface area, good stability, strong electron transport ability, many edge defects, high efficiency of activation, and less secondary pollution, the abundant active sites on its surface can bind and adsorb components such as proteins and amino acids in human excreta. Moreover, carbon nanotubes have good biocompatibility and can be used as the substrate material for microorganism culture. Therefore, the present invention uses activated sludge doped with carbon nanotubes as the substrate for microorganism culture. This composite substrate material has a good purification effect on chemical pollutants. And the present invention uses a sequencing batch reactor as the carrier device, loading the composite substrate material formed by activated sludge doped with carbon nanotubes for culturing microorganisms.

[0051] The present invention uses biochemical degradation technology to purify and separate most of the chemical pollutants in the waste liquid, creating favorable conditions for subsequent further membrane separation treatment.

[0052] As a specific embodiment of the present invention, the membrane separation module 4 includes an ultrafiltration device and a reverse osmosis device connected in series. The cut-off particle size of the ultrafiltration membrane of the ultrafiltration device is 0.001 - 0.1 μm, and the cut-off particle size of the reverse osmosis membrane of the reverse osmosis device is 1×10 -10 m - 10×10 -10 m.

[0053] Specifically, the membrane separation module 4 adopts a combined technology of ultrafiltration and reverse osmosis. The ultrafiltration device is a membrane process that uses pressure difference as the driving force and separates by the "screening" effect of the membrane. The ultrafiltration membrane can intercept fine suspended solids, microorganisms, bacteria, colloids, rust and other pollutants, and the intercepted particle size range is 0.001 - 0.1 μm. During the ultrafiltration process, the medium is not easy to fall off, there is no impurity dissolution, it is non-toxic, easy to use and replace, and has a long service life. Using the ultrafiltration device for pre-filtration of the reverse osmosis device can first remove various impurities in the waste liquid to improve the purification efficiency of the subsequent reverse osmosis membrane and extend its service life. The reverse osmosis device utilizes the property that the reverse osmosis membrane can only selectively permeate the solvent and intercept ionic substances. With the static pressure difference on both sides of the membrane as the driving force, overcoming the osmotic pressure of the solvent, the solvent permeates through the reverse osmosis membrane to achieve the separation of the liquid mixture, and the intercepted components are (1 - 10)×10 -10m small molecule solutes, removing almost all suspended solids, dissolved substances and colloids from the liquid mixture. The reverse osmosis membrane has excellent removal efficiency for salts. The selective permeability of the reverse osmosis membrane is related to the dissolution, adsorption and diffusion of components in the membrane, and is closely related to the pore size, structure, physical and chemical properties of the membrane itself. The rule of the removal rate of the reverse osmosis membrane for different solutes is as follows: for inorganic ions, the removal rate increases with the increase of the valence state of the ions. When the valence states are the same, the removal rate varies with the different radii of the ions. The order of the removal rates of common cations is: Al 3+ >Fe 3+ >Mg 2+ >Ca 2+ >Na + >NH 4+ >K + . The order of the removal rates of common anions is: SO4 2- >CO3 2- >Cl - >PO4 3- >F - >

[0054] NO 3- . The order of the removal rates of polar organic compounds is: aldehyde > alcohol > amine > acid, tertiary amine > secondary amine > primary amine, citric acid > tartaric acid > malic acid > lactic acid > acetic acid. For organic compounds in the same family, generally, the larger the molecular weight, the better the separation performance. Through the investigation of relevant reverse osmosis membrane products and combining with the change rule of the removal efficiency of the reverse osmosis membrane for various solutes, the removal rates of the relevant solutes contained in the radioactive medical waste liquid by the reverse osmosis membrane are shown in Table 1. Since the 131 I concentration in the radioactive nuclides in the waste liquid is the highest and the half-life is the longest, 131 I exists in the waste liquid in the ionic form of NaI. Referring to the removal rate of NaI by the reverse osmosis membrane being 97%, after passing through the microfiltration membrane and two-stage reverse osmosis membranes, the decontamination factor of 131 I in the waste liquid is about 1000.

[0055] Table 1 Removal rates of various solutes by the reverse osmosis membrane

[0056] Component NaI NaCl <![CDATA[Na2HPO4]]> KCl Removal rate 97％ 99％ 98％ 98％ Component <![CDATA[Na2CO3]]> <![CDATA[CaCl2]]> <![CDATA[MgSO4]]> <![CDATA[Na2SO4]]> Removal rate 95％ 99％ 98％ 96％ Component Urea Hippuric acid Creatinine COD Removal rate 70％ 82％ 85％ 97％

[0057] The present invention uses membrane separation technology to further purify and separate a small amount of chemical pollutants in the waste liquid, and at the same time purifies and separates the salts and most of the radioactive nuclides in the waste liquid, so that the content of chemical pollutants in the waste liquid meets the discharge limit, creating favorable conditions for subsequent ion exchange treatment.

[0058] As a specific embodiment of the present invention, the ion exchange module 5 adopts a structural mode in which an anion exchange resin column, a cation exchange resin column, and a mixed anion and cation exchange column are connected in series. Among them, the ion exchange column can be filled with inorganic adsorption materials including activated carbon, molecular sieve, graphene, zirconium phosphate, and collagen fiber.

[0059] After the radionuclides in the radioactive medical waste liquid are purified by the front-end solid-liquid separation, biochemical degradation, and membrane separation processes, since the suspended and colloidal radionuclides are removed, almost all the remaining radionuclides are in ionic state. In addition, the membrane separation process greatly purifies the salts in the waste liquid, which can reduce the competitive adsorption effect of impurity ions. The ion exchange column equipment can also be filled with excellent inorganic adsorption materials for the adsorption of radionuclides, such as activated carbon, molecular sieve, graphene, zirconium phosphate, collagen fiber, etc. The bench test results of the adsorption performance of various adsorption materials for 131 I nuclide show that the adsorption capacity for 131 I nuclide is ranked from high to low as follows: anion exchange resin > silver-loaded activated carbon > silver-loaded molecular sieve > activated carbon. The anion exchange resin has the best purification effect. The anion exchange resin and silver-loaded activated carbon are used in series for two-stage treatment to further improve the purification coefficient of 131 I.

[0060] The present invention uses ion exchange technology to further purify and separate the radionuclides in the waste liquid, so that the radionuclide content in the waste liquid meets the requirements of the discharge limit.

[0061] The on-line monitoring device 6 is an integrated device that combines a liquid sample collection device and a detection device. The on-line monitoring technology analyzes and calculates the total α / total β radioactivity concentration in the water by extracting the water sample to be monitored. If the treated waste liquid meets the discharge limit requirements of the national standard for various pollutants and radionuclides, it is directly discharged from the purified water collection tank. If the waste liquid still does not meet the discharge limit requirements of the national standard for various pollutants and radionuclides, the waste liquid returns to the purification treatment system for further purification. The on-line monitoring device 6 of the present invention integrates the sampling, measurement, reading, etc. of the sample on one device, which not only effectively solves the problem of the difficulty in real-time monitoring of the radioactive level after purification of the radioactive medical waste liquid purification device, but also solves the problems of many types of detection equipment, scattered distribution, large floor area, and easy spillage of samples in the detection of the radioactivity of wastewater.

[0062] A radioactive medical waste liquid purification treatment modular system and its purification treatment method provided by the present invention adopt modular and automated design for the whole technical route, integrate a number of treatment processes, and the treatment capacity is 0.4 - 1 m 3 / h. It has a certain degree of flexibility in process operation. According to the water quality parameters of radioactive medical waste liquid and the purification treatment requirements, several of these process devices can be selected for targeted purification treatment. During the treatment process of the waste liquid, it is necessary to determine the number, sequence, and combination method of each wastewater treatment process module. Each process can be combined according to the waste liquid source term under different conditions, enabling series-parallel connection and rapid assembly of the modules. The treatment process is fully automated remotely, and the treatment capacity and purification coefficient can be adjusted. For some typical usage scenarios and requirements, the module combination methods are shown in Table 2.

[0063] Table 2 Module combination methods for typical usage scenarios

[0064]

[0065] The modular system for purifying radioactive medical waste liquid and its purification treatment method provided by the present invention can achieve real-time purification treatment of medium- and long-half-life radionuclides, breaking through the technical bottleneck of traditional storage decay technology compared with the traditional storage decay technology. Moreover, it can also achieve simultaneous collection, simultaneous treatment, and simultaneous discharge of radioactive medical waste liquid, reducing the purification treatment cycle of the waste liquid, having the advantage of timeliness, and reducing the risk of long-term storage of the waste liquid. At the same time, it can also save a large amount of space and has strong economic advantages, showing good application prospects in the field of nuclear medicine radioactive waste treatment.

[0066] The purification treatment method of a modular system for purifying radioactive medical waste liquid provided by the present invention has the following specific working process:

[0067] 1) Waste liquid collection: The radioactive medical waste liquid enters the waste liquid collection equipment 1 such as a collection tank or a collection pool by means of gravity flow for collection.

[0068] 2) The radioactive medical waste liquid collected by the waste liquid collection equipment 1 enters the solid-liquid separation module 2. The waste liquid is sequentially conveyed to the filter equipment in the module through the screw centrifuge in the solid-liquid separation module 2. Most of the sundries and solid suspended matters are separated, and some pollutants such as microorganisms, heavy metal ions, chlorine elements, and organic matters are purified, effectively reducing the COD value in the waste liquid. Among them, the separated solid impurities are discharged into the waste collection bucket for collection.

[0069] 3) The waste liquid treated by the solid-liquid separation module 2 is conveyed to the biochemical reaction module 3 through the sewage pump arranged on the pipeline connecting the solid-liquid separation module 2 and the biochemical reaction module 3 after passing through the solid-liquid separation device. After the waste liquid is fully contacted with the composite material of activated sludge doped with carbon nanotubes in the biochemical reaction module 3, a biodegradation reaction occurs to achieve the purification and separation of most chemical pollutants.

[0070] 4) The waste liquid treated by the biochemical reaction module 3 is transported to the membrane separation module 4 through a booster pump installed on the pipeline connecting the biochemical reaction module 3 and the membrane separation module 4. Under the action of pressure, the waste liquid sequentially passes through the ultrafiltration membrane assembly and the reverse osmosis membrane assembly. A small amount of chemical pollutants in the formed clear liquid are deeply purified to meet the discharge limit requirements, and a large amount of radionuclides and salts are purified and separated. The formed concentrated liquid is absorbed and collected by an absorbent material.

[0071] 5) The clear liquid collected by the membrane separation module 4 is transported to the ion exchange module 5 through a centrifugal pump installed on the pipeline connecting the membrane separation module 4 and the ion exchange module 5. The clear liquid sequentially passes through the anion exchange resin column, the cation exchange resin column, and the anion-cation mixed ion exchange column in the ion exchange module 5 to complete the adsorption and separation of radionuclides. The purified waste liquid is continuously transported to the on-line monitoring device 6 for monitoring.

[0072] 6) After the purified waste liquid flows through the on-line monitoring device 6, the device measures and reads the activity level of the waste liquid in real time, and the data is converted into a control signal for automatically controlling the switching direction of the three-way valve. If the discharge limit requirements are met, the valve switches to the purified water collection tank pipeline, and the waste liquid is transported to the purified water collection tank for collection and subsequent tank discharge. If the discharge limit requirements are not met, the valve switches to the waste liquid collection device 1 pipeline, and the waste liquid is transported to the waste liquid collection device 1 for subsequent purification treatment again.

[0073] As other specific embodiments of the present invention, according to the water quality parameters of the radioactive medical waste liquid and the requirements of the actual application scenario, the required process modules can be flexibly selected through pipeline valve switching. The start and stop of the valves and pump-type active devices installed on the pipelines connecting the waste liquid collection device 1, the solid-liquid separation module 2, the biochemical reaction module 3, the membrane separation module 4, the ion exchange module 5, and the on-line monitoring device 6 are respectively controlled by remote automation operations. Several of these process devices are selected for series-parallel connection and rapid assembly to perform targeted purification treatment on the waste liquid. The main valves and pump-type active devices on its pipelines are all designed automatically and can be remotely operated. The overall treatment rate is controlled by adjusting the pump flow rate and the valve opening. In this way, not only can the waste liquid achieve long-distance fully automated operation during the treatment process, with a certain degree of flexibility in the process operation, but also the treatment capacity and purification coefficient can be adjusted, and targeted regulation can be carried out for some typical use scenarios and requirements, which can greatly improve the purification treatment efficiency of the radioactive medical waste liquid.

[0074] The modular system for purifying and treating radioactive medical waste liquid and its purification and treatment method provided by the present invention adopt a modular design, can perform module series-parallel connection and rapid assembly according to different water quality conditions and treatment requirements, can improve the purification efficiency of the waste liquid, and its purification and treatment capacity can reach 0.4 - 1.0 m 3 / h, various indicators of the purified effluent can meet the requirements of relevant national standards for the discharge of medical waste liquid, and the radioactive indicator is total β < 10 Bq / L. The device is integrated in a container-type box, occupying a small space and meeting various usage requirements of users.

[0075] Moreover, in order to reduce the pollution of ambient air, for the radioactive medical waste liquid purification and treatment modular system and its purification and treatment method provided by the present invention, the waste liquid collection device 1, the solid-liquid separation module 2, the biochemical reaction module 3 and the ion exchange module 4 are respectively connected to a gas filter and an industrial vacuum cleaner through exhaust pipes. During the purification and treatment process of the waste liquid, process exhaust gas and aerosols and other waste gases generated in the purification and treatment system can enter devices such as a high-efficiency gas filter and an industrial vacuum cleaner through the exhaust pipes for purification and treatment, and are discharged after reaching the standard, thereby reducing air pollution and being green and environmentally friendly.

[0076] At the same time, for the radioactive medical waste liquid purification and treatment modular system and its purification and treatment method provided by the present invention, the ion exchange module 4 is connected to a mobile suction device. After the adsorption material in the ion exchange module 4 fails due to long-term use, these waste adsorption materials can be pumped out through the mobile suction device and stored in a waste steel drum, and then new adsorption materials are added to the ion exchange module 4. Moreover, the filter element of the solid-liquid separation module 2 and the membrane module of the membrane separation module 5 are both designed as an overall quick-disassembly type that can be integrally disassembled and replaced. After the filter element of the solid-liquid separation module 2 and the membrane module of the membrane separation module 5 fail due to long-term use, the filter element of the solid-liquid separation module 2 and the membrane module of the membrane separation module 5 can be conveniently disassembled and replaced by the grasping tool of a portable manipulator, and the replaced waste membrane module and filter element are stored in a waste steel drum.

[0077] Therefore, for the radioactive medical waste liquid purification and treatment modular system and its purification and treatment method provided by the present invention, by using portable suction and grasping tools, secondary wastes such as waste adsorption materials, waste components and waste filter elements generated in the purification and treatment system are suctioned and disassembled, and collected in a waste steel drum, which is convenient for personnel to operate at a distance, effectively manages the secondary wastes generated in the purification and treatment system, and realizes the optimization of personnel radiation protection.

[0078] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the examples, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered by the scope of the claims of the present invention.

Claims

1. A modular system for purifying radioactive medical waste liquid, characterized in that: It includes a waste liquid collection device, a solid-liquid separation module connected to the waste liquid collection device through a pipeline, a biochemical reaction module connected to the solid-liquid separation module through a pipeline, a membrane separation module connected to the biochemical reaction module through a pipeline, an ion exchange module connected to the membrane separation module through a pipeline, and an online monitoring device connected to the ion exchange module through a pipeline, wherein the online monitoring device is connected to a purified water collection tank; The waste liquid collection equipment, solid-liquid separation module, biochemical reaction module and ion exchange module are connected to the gas filter and industrial vacuum cleaner through an exhaust pipe; The ion exchange module is connected to a mobile suction device, and the waste adsorption material in the ion exchange module is extracted and stored in a waste steel barrel; The filter element of the solid-liquid separation module and the membrane assembly of the membrane separation module are both of an integral quick-disassembly design that can be integrally loaded, unloaded and replaced by a robot, and the replaced waste membrane assembly and filter element are stored in a waste steel barrel; The modules can be used in series and parallel combinations according to user requirements and waste liquid source parameters to meet different usage requirements.

2. The modular system for purifying radioactive medical waste liquid according to claim 1, characterized in that: The waste liquid collection equipment is connected to the biochemical reaction module pipeline, the solid-liquid separation module is connected to the membrane separation module pipeline, the biochemical reaction module is connected to the ion exchange module pipeline, the membrane separation module is connected to the online monitoring device pipeline, and the online monitoring device is connected to the waste liquid collection equipment pipeline.

3. The modular system for purifying radioactive medical waste liquid according to claim 2, characterized in that: The start and stop of valves and pump-type active equipment on the connecting pipelines of the waste liquid collection equipment, solid-liquid separation module, biochemical reaction module, membrane separation module, ion exchange module, online monitoring device and purified water collection tank can be remotely and automatically controlled.

4. The modular system for purifying radioactive medical waste liquid according to claim 3 is characterized in that: The solid-liquid separation module comprises a spiral centrifuge, an activated carbon filter and a filter bag type filter which are sequentially connected in series, and the filter bag type filter adopts a filter element with a filtration accuracy of 45 μm.

5. The modular system for purifying radioactive medical waste liquid according to claim 2, characterized in that: The biochemical reaction module adopts a sequencing batch reactor, and the sequencing batch reactor is loaded with a composite substrate material formed by activated sludge doped with carbon nanotubes for culturing microorganisms.

6. The modular system for purifying radioactive medical waste liquid according to claim 2, characterized in that: The membrane separation module comprises an ultrafiltration device and a reverse osmosis device connected in series, wherein the cut-off particle size of the ultrafiltration membrane of the ultrafiltration device is 0.001-0.1 μm, and the cut-off particle size of the reverse osmosis membrane of the reverse osmosis device is 1×10 -10 m-10×10 -10 m.

7. The modular system for purifying radioactive medical waste liquid according to claim 2, characterized in that: The ion exchange module adopts a structural mode in which an anion exchange resin column, a cation exchange resin column and a cation-cation mixed ion exchange column are connected in series.

8. The modular system for purifying radioactive medical waste liquid according to claim 7, characterized in that: The ion exchange column may be filled with inorganic adsorption materials including activated carbon, molecular sieve, graphene, zirconium phosphate and collagen fiber.

9. A method for purifying radioactive medical waste liquid, using the modular system for purifying radioactive medical waste liquid according to any one of claims 1 to 8, characterized in that: The steps include: The solid-liquid separation module is used to separate the waste liquid into solid and liquid to remove the suspended solids in the waste liquid; Biodegradation of waste liquid by biochemical reaction module to decompose chemical pollutants in waste liquid; Removing chemical pollutants, salts and radionuclides from wastewater through membrane separation modules; Removal of radionuclides from wastewater by ion exchange modules; The purified waste liquid is monitored by an online monitoring device and discharged from the purified water collection tank if it meets the standards. Otherwise, it returns to the waste liquid collection tank for further purification. The exhaled gas and aerosol generated during the purification process enter the gas filter and industrial vacuum cleaner through the exhaust pipe for purification; During the purification process, the waste adsorption materials of the ion exchange module are extracted by a mobile suction device and stored in a waste steel drum; During the purification process, the waste filter element of the solid-liquid separation module and the waste membrane assembly of the membrane separation module are replaced as a whole by the robot and stored in a waste steel barrel.

10. The method for purifying radioactive medical waste liquid according to claim 9, characterized in that: The microorganisms cultured in the biochemical reaction module can decompose chemical pollutants in the waste liquid including ammonia nitrogen organic compounds, urea, ammonium phosphate, creatinine, lyosol and metal chelate.

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