01, the use of chemical precipitation to deal with nuclear wastewater
In fact, this method is the use of some precipitant and nuclear wastewater radionuclides to occur *** precipitation, in fact, there are a large number of radionuclides in the wastewater, which contains hydroxide, carbonate and phosphate, etc., and most of these substances are insoluble, so can be removed when dealing with wastewater. These substances are mostly insoluble and can be removed when treating wastewater. Using this method, the radioactive substances in the nuclear wastewater can be transferred to a small volume of sludge inside, the final precipitation of the wastewater, the content of radioactive substances will be particularly low, so as to meet the discharge standards.
02, the use of ion exchange method to deal with nuclear wastewater
This method is also a relatively common treatment method, mainly the use of exchange resins to deal with the exchange resin on the radioactive substances have a relatively high removal capacity, while there is a certain exchange capacity. You, for example, powder aldehyde type cation resin can be very good to remove the radioactive material, in addition to macroporous type cation resin can also remove the radioactive cations. However, this treatment method also has a weakness, if the content of radioactive substances in the wastewater is relatively high, then the resin bed will soon penetrate and fail. Therefore, in the actual use of the process, if once the failure should be replaced immediately.
03, the use of adsorption to deal with nuclear wastewater
In fact, it is the use of some adsorbents to deal with these wastewater, the more common adsorbents are activated carbon, kaolin, bentonite, clay, zeolite and so on, the most common is actually zeolite, because this material is relatively inexpensive, and at the same time it is also very easy to get. The adsorption capacity of this substance is relatively good, the purification effect is also particularly great, the evolution of zeolite is about 10 times higher than other adsorbents. So in the treatment of wastewater, zeolite is considered a more competitive water treatment chemicals.
04, the use of evaporation and concentration method to deal with nuclear wastewater
In the operation of the wastewater will be sent directly to the evaporation device inside, and then directly evaporate the water into water vapor, in this process, those radioactive elements will remain in the water. The condensate formed during evaporation can be discharged or recycled.
How does China deal with nuclear wastewater?
China's treatment of nuclear wastewater:
1. If the amount is not large, tritium and water can be evaporated directly as long as the discharge is controlled.
2. Landfill the remaining solid waste in situ, but tritium may pollute the air.
3, by adsorption of the solid waste out first, after sucking it out, the solid waste is still taken to the landfill, and then the rest of the wastewater will be discharged directly into the sea, or stored in tanks to slow down for a while.
4, the purpose of wastewater treatment is the pollutants in the wastewater in a certain way to separate out, or its decomposition into harmless and stable substances, so that the sewage is purified.
5, generally to achieve to prevent the transmission of poisons and germs; to avoid the smell and malodorous visible matter to meet the requirements of different uses.
6, wastewater treatment is quite complex, the choice of treatment methods, must be based on the quality and quantity of wastewater, discharged into the receiving body of water or water use to consider.
At the same time, we must also consider the wastewater treatment process of sludge, residue treatment and utilization and possible secondary pollution problems, as well as the recycling of flocculants and so on.
Pollution caused by industrial wastewater:
Organic aerobic material pollution, chemical toxic pollution, inorganic solid suspended solids pollution, heavy metal pollution, acid pollution, alkali pollution, plant nutrient pollution, thermal pollution, pathogen pollution.
Many pollutants have color, odor or easy to generate foam, so industrial wastewater often presents a disgusting appearance, resulting in widespread pollution of water bodies, a direct threat to people's lives and health, so it is particularly important to control industrial wastewater.
The above reference? Baidu Encyclopedia - Industrial Wastewater
How is China's nuclear wastewater treated?
China's treatment of low and medium-level radioactive nuclear waste is handled according to national standards and the requirements of the International Atomic Energy Agency. Whether it is solid or liquid nuclear waste, it is solidified and then put in 200-liter stainless steel drums and placed in shallow ground-level repositories.
Currently, China has built two medium- and low-radiation nuclear waste repositories and is preparing to build two more, but does not yet have a high-radiation repository. The two repositories for low- and medium-radiation nuclear waste have been built in Yumen, Gansu province, and Beilong, near Daya Bay, Guangdong province.
The Gansu Yumen Northwest Disposal Site is located in the former Nuclear Industry 404 Plant, one of China's earliest nuclear industry bases. Guangdong Beilong disposal site was built in 1998, completed in 2000, is located in the Dapeng Peninsula, Paiya Mountain, east of a gently sloping hill beam, 5 kilometers from the Daya Bay nuclear power plant, saw Lingao nuclear power plant 4 kilometers. Covering an area of nearly 21 hectares, it is designed to have a total disposal capacity of 80,000 cubic meters, with a project cost of about RMB 80 million. It mainly receives and disposes of low to medium level radioactive solid wastes generated from nuclear power plants in Guangdong Province.
For the widely adopted pressurized water reactor (PWR) nuclear power plants, the treatment processes for various types of wastewater are as follows:
Process wastewater. Mainly hydrophobic and pilot leakage water from coolant related systems. Depending on its radioactivity level and salt content, it can be treated by pre-filtration, ion exchange and evaporation.
Equipment decontamination wastewater. Mainly for radioactive equipment decontamination of decontamination wastewater, its salt content is higher, generally used evaporation treatment.
Ground washing wastewater, shower water and laundry water. This type of wastewater has a very low level of radioactivity and can be discharged after filtration, or treated by evaporation or membrane filtration. If the wastewater contains detergents, an antifoaming agent needs to be added during evaporation, or the detergents need to be pre-decomposed. Radioactive waste water generated by nuclear power plants belongs to the medium and low discharge, after purification, concentration, the use of plastic, epoxy resin, etc., cured in metal drums; for low discharge waste water after the above purification treatment, the test meets the prescribed value of diluted discharge.
How to deal with the wastewater discharged from the nuclear power plant
1, chemical precipitation method
Chemical precipitation method is the precipitant and the wastewater trace radionuclides in the **** precipitation method. Wastewater radionuclides in the hydroxide, carbonate, phosphate and other compounds are mostly insoluble, and thus can be removed in the treatment.
The purpose of chemical treatment is to transfer and concentrate the radionuclides in the wastewater into a small volume of sludge, while leaving little radioactivity remaining in the wastewater after deposition, so that discharge standards can be met.
2, ion exchange method
Ion exchange method using ion exchange resin, suitable for waste water with low salt content. When the salt content is high, the cost spent on treatment with ion exchange resin is higher than the selective process. This is mainly due to the fact that low selectivity resins are highly correlated to radionuclides. In the purification of radioactive wastewater, the use of electrodialysis can increase the efficiency of the utilization of the ion exchange process.
3, adsorption method
Adsorption method is the use of porous solid material adsorption to remove heavy metal ions in water is an effective method. The key technology of adsorption method is the selection of adsorbent. Commonly used adsorbents are activated carbon, zeolite, kaolin, bentonite, clay and so on.
4, evaporation and concentration
Evaporation and concentration method has a high concentration factor and purification coefficient, mostly used in the treatment of medium and high levels of radioactive wastewater. The working principle of the evaporation method is: the radioactive wastewater into the evaporation device, while the introduction of heated steam will evaporate into water vapor, while the radionuclides remain in the water. The condensate formed during the evaporation process is discharged or reused, and the concentrate is further solidified.
5, membrane separation technology
Membrane technology is a more efficient, economical and reliable method of treating radioactive wastewater. Due to the membrane separation technology with good water quality, materials without phase change, low energy consumption and other characteristics, membrane technology has been actively studied.
6, biological treatment method
Biological treatment method includes phytoremediation and microbial method. Phytoremediation refers to the use of green plants and their inter-root indigenous microorganisms *** with the role of removing pollutants in the environment of a new in situ treatment technology.
7, magnetic - molecular method
This method is based on a protein called ferritin, will be modified, the use of magnetic molecules to selectively bind the pollutants, and then use a magnet to remove them from the solution, and then be combined with the metal through the backwash magnetic filter bed to get recycled.
8, inert solidification method
This new process uses low-temperature solidification to stabilize the high alkalinity, low activity of the radioactive waste liquid, that is, the waste liquid into an inert solidified body.
9, zero-valent iron percolation reaction wall technology
The percolation reaction wall is currently in Europe and the United States and other developed countries emerging for the in situ removal of contaminated groundwater contamination components of the method. PRB is generally installed in the aquifer, perpendicular to the direction of the groundwater flow, when the contaminated groundwater flow in its own hydraulic gradient under the action of the reaction wall, the pollutant and the wall of the reaction material Physical and chemical reactions occur and are removed, thus achieving the purpose of pollution remediation.
How is nuclear wastewater treated in China?
Nuclear pollution and waste water treatment methods:
The precipitant and the trace radionuclides in the waste water *** precipitation method. Hydroxides, carbonates, phosphates and other compounds of radionuclides in wastewater are mostly insoluble and thus can be removed in the treatment.
The purpose of chemical treatment is to transfer and concentrate the radionuclides in the wastewater into a small volume of sludge, leaving very little radioactivity remaining in the wastewater after deposition so that discharge standards can be met.
The advantages of this method are that it is inexpensive, has a good effect on the removal of a number of radionuclides, and is able to deal with those non-radioactive components and their concentrations as well as wastewater with considerable fluidization, and the treatment facilities and technologies used are quite mature and experienced.
Expanded information:
Nuclear power plant wastewater mainly includes the main equipment and auxiliary equipment evacuation water, the reactor discharge water, the second loop of wastewater, cleaning wastewater, regeneration wastewater from the ion exchange device and special washing water, mainly for the medium and low radioactive wastewater.
Spent fuel reprocessing wastewater mainly includes spent fuel reprocessing and wastewater generated from the process of radioactive material separation and manufacturing, etc., both of which have high radioactive concentrations and are extremely dangerous.
People's Daily Online - How to deal with Fukushima nuclear wastewater? A number of Japanese officials mentioned "discharged into the sea."