Nuclear power station temporary wastewater treatment method and device

Abstract

The invention provides a method and a device for treating temporary wastewater of a nuclear power plant. The method comprises the following steps: inputting pretreated temporary wastewater of the nuclear power plant into a reaction tank from an adjusting tank; in a reaction tank, adjusting the pH value of the pretreated wastewater to a first target value, and sequentially adding a ferrous sulfate solution and hydrogen peroxide to form a first mixture; inputting the first mixture into a sedimentation tank; in the sedimentation tank, the pH value of the first mixture is adjusted to a second target value, a coagulant and / or a coagulant aid are / is sequentially added, a second mixture is formed, and the second mixture comprises the first suspension liquid; inputting the first suspension into an advanced treatment device for advanced treatment to form a first solution; inputting the first solution into a water outlet tank for disinfection treatment to form a second solution; and after detecting that the second solution reaches the standard, discharging the second solution. And the second solution reaching the standard can be directly discharged to a drainage basin, so that the treatment effect can be improved by adopting the temporary wastewater treatment method for the nuclear power station provided by the invention to treat the temporary wastewater of the nuclear power station.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of industrial water treatment, in particular to a temporary wastewater treatment method and device for a nuclear power plant. BACKGROUND

[0002] During the commissioning of some nuclear power projects, different amounts of chemical substances such as hydrazine, acetate, boric acid, corrosion inhibitor, etc. are added to the primary loop and the secondary loop to adjust the water quality of the primary loop and the secondary loop to meet the working condition of the nuclear power in operation, so a large amount of temporary wastewater is generated during the commissioning of the nuclear power plant.

[0003] At present, the wastewater generated during the construction and commissioning of the nuclear power plant is treated by a first Fenton reaction tank, a first Fenton sedimentation tank, a second Fenton reaction, and a second Fenton sedimentation tank. Although the treated wastewater can meet the comprehensive wastewater discharge standard, it cannot be directly discharged into the river basin, and the treatment effect of the wastewater generated during the construction of the nuclear power plant is poor. SUMMARY

[0004] The embodiments of the present application provide a temporary wastewater treatment method and device for a nuclear power plant, which can solve the problem of poor treatment effect of the temporary wastewater of the nuclear power plant.

[0005] In order to solve the above technical problems, the present application is implemented as follows:

[0006] In a first aspect, the embodiments of the present application provide a temporary wastewater treatment method for a nuclear power plant, which is applied to a temporary wastewater treatment system for a nuclear power plant, the temporary wastewater treatment system for the nuclear power plant comprising a conditioning tank, a reaction tank, a sedimentation tank, a deep treatment device, and an effluent tank, an output end of the conditioning tank being in communication with an input end of the reaction tank, an output end of the reaction tank being in communication with an input end of the sedimentation tank, the sedimentation tank comprising a first output end, the first output end being in communication with an input end of the deep treatment device, an output end of the deep treatment device being in communication with the effluent tank.

[0007] The method comprises:

[0008] The pre-processed temporary wastewater of the nuclear power plant is input from the conditioning tank to the reaction tank;

[0009] In the reaction tank, the pH value of the pre-processed wastewater is adjusted to a first target value, and ferrous sulfate solution and hydrogen peroxide are sequentially added to form a first mixture;

[0010] The first mixture is input into the sedimentation tank;

[0011] In the sedimentation tank, the pH value of the first mixture is adjusted to a second target value, and a coagulant and / or a coagulant aid are sequentially added to form a second mixture, the second mixture comprising a first suspension;

[0012] inputting the first suspension into a deep treatment device for deep treatment to form a first solution;

[0013] inputting the first solution into a water outlet pool for disinfection treatment to form a second solution;

[0014] discharging the second solution after detecting that the second solution meets a standard;

[0015] wherein the first target value is less than the second target value, and the first target value is an acidic value and the second target value is an alkaline value.

[0016] Optionally, the temporary nuclear power plant wastewater treatment system further comprises a sludge concentration pool, and the sedimentation pool further comprises a second output end, the second output end being in communication with the sludge concentration pool, and the second mixture further comprises sludge.

[0017] The method further comprises:

[0018] inputting the sludge into the sludge concentration pool for concentration treatment.

[0019] Optionally, the pretreatment comprises:

[0020] performing at least two levels of filtration treatment on the nuclear power plant temporary wastewater to be treated.

[0021] Optionally, the reaction pool comprises a primary reaction pool and a secondary reaction pool, the output end of the conditioning pool being in communication with the input end of the first reaction pool, the output end of the primary reaction pool being in communication with the input end of the secondary reaction pool, and the output end of the secondary reaction pool being in communication with the input end of the sedimentation pool.

[0022] Optionally, the temporary nuclear power plant wastewater treatment system further comprises a chemical oxygen demand online monitoring instrument, an ammonia nitrogen online monitoring instrument, a total nitrogen online monitoring instrument, and a total phosphorus online monitoring instrument arranged in the water outlet pool.

[0023] Optionally, in the sedimentation pool, the agent for adjusting the pH value comprises at least one of calcium oxide, calcium hydroxide, and sodium hydroxide.

[0024] Optionally, the coagulant comprises at least one of polyaluminum chloride, polyferric chloride, and polyferric sulfate.

[0025] The coagulant aid comprises at least one of cationic polyacrylamide, anionic polyacrylamide, and nonionic polyacrylamide.

[0026] Optionally, the sedimentation pool is any one of an inclined tube sedimentation pool, an inclined plate sedimentation pool, a horizontal flow sedimentation pool, and a radial flow sedimentation pool.

[0027] and / or,

[0028] The depth treatment device is any one of a sand filter, a quartz sand filter, and an activated carbon filter.

[0029] Optionally, the disinfection of the effluent tank uses any one of sodium hypochlorite, ozone, liquid chlorine, and chlorine dioxide.

[0030] In a second aspect, the present application provides a temporary nuclear power plant wastewater treatment device, which comprises the temporary nuclear power plant wastewater treatment system, and the temporary nuclear power plant wastewater treatment system further comprises an adjusting tank, a reaction tank, a sedimentation tank, a depth treatment device, and an effluent tank, wherein the output end of the adjusting tank is connected to the input end of the reaction tank, the output end of the reaction tank is connected to the input end of the sedimentation tank, the sedimentation tank comprises a first output end, the first output end is connected to the input end of the depth treatment device, and the output end of the depth treatment device is connected to the effluent tank.

[0031] The temporary nuclear power plant wastewater treatment device is used for:

[0032] inputting the pre-processed temporary nuclear power plant wastewater from the adjusting tank into the reaction tank;

[0033] adjusting the pH value of the pre-processed wastewater to a first target value in the reaction tank, and sequentially adding ferrous sulfate solution and hydrogen peroxide to form a first mixture;

[0034] inputting the first mixture into the sedimentation tank;

[0035] adjusting the pH value of the first mixture to a second target value in the sedimentation tank, sequentially adding a coagulant and / or a coagulant aid to form a second mixture, and the second mixture comprises a first suspension;

[0036] inputting the first suspension into the depth treatment device for depth treatment to form a first solution;

[0037] inputting the first solution into the effluent tank for disinfection treatment to form a second solution;

[0038] discharging the second solution after detecting that the second solution meets the standard;

[0039] wherein the first target value is less than the second target value, and the first target value is an acidic value and the second target value is an alkaline value.

[0040] In the embodiment of the present application, the pretreated temporary wastewater of the nuclear power plant is input from the adjusting tank to the reaction tank; in the reaction tank, the pH value of the pretreated wastewater is adjusted to a first target value, and ferrous sulfate solution and hydrogen peroxide are sequentially added to form a first mixture; the first mixture is input to the precipitation tank; in the precipitation tank, the pH value of the first mixture is adjusted to a second target value, and a coagulant and / or a coagulant aid are sequentially added to form a second mixture, and the second mixture comprises a first suspension; the first suspension is input to a deep treatment device for deep treatment to form a first solution; the first solution is input to a water outlet tank for disinfection treatment to form a second solution; after detecting that the second solution meets the standard, the second solution is discharged. The second solution meeting the standard can be directly discharged to a river basin. It can be seen that, by using the nuclear power plant temporary wastewater treatment method provided in the present application to treat the temporary wastewater of the nuclear power plant, the treatment effect can be improved. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 A flowchart of a nuclear power plant temporary wastewater treatment method provided in the embodiment of the present application is shown in the figure.

[0042] Figure 2 A running flowchart of a nuclear power plant temporary wastewater treatment system provided in the embodiment of the present application is shown in the figure. DETAILED DESCRIPTION

[0043] The technical solutions in the embodiments of the present application will be clearly and completely described in combination with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0044] Unless otherwise defined, the technical terms or scientific terms used in the present application should be understood as the common meanings understood by those skilled in the art. The terms "first", "second", and similar terms used in the present application do not represent any order, number, or importance, but are only used to distinguish different components. Similarly, "one" or "a" and similar terms do not represent a quantity limitation, but represent the existence of at least one. The terms "connected" or "connected" and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right", and the like are only used to represent relative positional relationships, and when the absolute positions of the described objects change, the relative positional relationships also change accordingly.

[0045] The nuclear power plant temporary wastewater treatment method and device provided in the present application will be further described below in combination with the accompanying drawings.

[0046] It should be understood that the nuclear power plant temporary wastewater treatment method provided by the present application is applied to a nuclear power plant temporary wastewater treatment device. The nuclear power plant temporary wastewater treatment device comprises a nuclear power plant temporary wastewater treatment system, and the nuclear power plant temporary wastewater treatment system comprises a conditioning tank, a reaction tank, a sedimentation tank, a deep treatment device and a water outlet tank. The output end of the conditioning tank is connected to the input end of the reaction tank, the output end of the reaction tank is connected to the input end of the sedimentation tank, the sedimentation tank comprises a first output end, the first output end is connected to the input end of the deep treatment device, and the output end of the deep treatment device is connected to the water outlet tank.

[0047] Please refer to Figure 1 , Figure 1 A flowchart of a nuclear power plant temporary wastewater treatment method provided by an embodiment of the present application is shown in the figure. The method comprises the following steps:

[0048] In step 110, the pre-processed nuclear power plant temporary wastewater is input from the conditioning tank to the reaction tank.

[0049] The pre-processed nuclear power plant temporary wastewater can be input into the conditioning tank through a lifting pump. The conditioning tank is used to adjust the water quality and quantity of the wastewater, so as to ensure the stability of the water quality entering the subsequent equipment. In this way, after the water quality is adjusted in the conditioning tank, the wastewater is input to the reaction tank through the lifting pump.

[0050] In step 120, the pH value of the pre-processed wastewater is adjusted to a first target value in the reaction tank, and ferrous sulfate solution and hydrogen peroxide are sequentially added to form a first mixture.

[0051] The reaction tank can comprise a pH adjustment zone, a catalytic reaction zone and an oxidation reaction zone. In step 110, the wastewater whose water quality is adjusted by the conditioning tank enters the pH adjustment zone in the reaction tank. An acidic solution is added in the pH adjustment zone to adjust the pH value of the wastewater to the first target value, wherein the first target value is an acidic value.

[0052] In an optional embodiment, the acidic solution for adjusting the pH value is a sulfuric acid solution.

[0053] In an optional embodiment, the pH value can be adjusted to the first target value by a pH on-line detector and automatic dosing control.

[0054] In an optional embodiment, the first target value can be 3-3.5.

[0055] The wastewater after pH adjustment enters the catalytic reaction zone and the oxidation reaction zone in sequence. In the reaction zone, ferrous sulfate solution and hydrogen peroxide are added to the wastewater with the pH value of the first target value. Since the ferrous sulfate solution and the hydrogen peroxide can effectively remove the pollutants such as dichromate oxidizability (COD Cr ), hydrazine, organic matter, etc. contained in the wastewater, a wastewater mixture in which the pollutants such as COD Cr , hydrazine, organic matter, etc. are removed, i.e. a first mixture, is formed.

[0056] In an optional embodiment, the residence time of the wastewater in the reaction tank can be 75-350 min.

[0057] In step 130, the first mixture is input into the sedimentation tank.

[0058] It should be understood that in the present application, the outlet water level of the reaction tank is higher than the inlet water level of the sedimentation tank. The first mixture in the reaction tank flows into the sedimentation tank through the inlet water port of the sedimentation tank in a self-flowing manner from the outlet water port of the reaction tank.

[0059] In an optional embodiment, the sedimentation tank is any one of a inclined tube sedimentation tank, an inclined plate sedimentation tank, a horizontal flow sedimentation tank, and a radial flow sedimentation tank.

[0060] In step 140, the pH value of the first mixture is adjusted to a second target value in the sedimentation tank, and a coagulant and / or a coagulant aid are added in sequence to form a second mixture, which includes a first suspension.

[0061] In the sedimentation tank, an alkaline solution is added to adjust the pH of the wastewater to the second target value, wherein the second target value is an alkaline value.

[0062] In an optional embodiment, the alkaline solution includes at least one of calcium oxide, calcium hydroxide, and sodium hydroxide.

[0063] In an optional embodiment, the adjustment of the pH value can be realized by a pH on-line detector and automatic dosing to control the pH value of the wastewater to be the second target value.

[0064] Since the first target value is an acidic value and the second target value is an alkaline value, it can be seen that the first target value is less than the second target value.

[0065] In an optional embodiment, the second target value can be 7.5-8.5.

[0066] The coagulant and / or the coagulant aid are added in sequence to the wastewater after pH adjustment, and after sufficient mixing, a second mixture is formed. The second mixture enters the sedimentation zone of the sedimentation tank, and the separation of sludge and water is realized in the sedimentation zone, and the first suspension is the upper suspension after the separation of sludge and water.

[0067] In an optional embodiment, the coagulant comprises at least one of polyaluminum chloride, polyferric chloride, and polyferric sulfate; and the coagulant aid comprises at least one of cationic polyacrylamide, anionic polyacrylamide, and non-ionic polyacrylamide.

[0068] At step 150, the first suspension is input into a deep treatment device for deep treatment, to form a first solution.

[0069] The first suspension is input into the deep treatment device, and the first suspension can stay in the deep treatment device for 0.5-4 hours. The deep treatment device can further remove pollutants such as suspended solids contained in the wastewater. The first suspension after being treated by the deep treatment device is the first solution.

[0070] In this embodiment, the wastewater treatment effect is improved by deep treatment of the first suspension by the deep treatment device.

[0071] In an optional embodiment, the deep treatment device is any one of a sand filter, a quartz sand filter, and an activated carbon filter.

[0072] In an optional embodiment, the deep treatment device comprises a backwashing system, so that the wastewater treatment effect of the deep treatment device is improved by backwashing the deep treatment device.

[0073] At step 160, the first solution is input into a water outlet tank for disinfection treatment, to form a second solution.

[0074] The first solution is input into the water outlet tank, and the first solution can stay in the water outlet tank for 1-4 hours. The water outlet tank is used to store water for backwashing the deep treatment device and temporarily store the treated wastewater. The first solution is disinfected in the water outlet tank, and the disinfection treatment can be chemical disinfection treatment. The first solution after disinfection treatment is the second solution.

[0075] In this embodiment, the wastewater treatment effect is improved by disinfection treatment of the first solution.

[0076] In an optional embodiment, the disinfectant can be any one of sodium hypochlorite, ozone, liquid chlorine, and chlorine dioxide.

[0077] At step 170, the second solution is discharged after it is detected to meet the standards.

[0078] detecting the index values of the second solution after the disinfection treatment, and discharging the second solution after all the index values meet the relevant discharge standards. The index values can include suspended solids, BOD5 (five-day biochemical oxygen demand (Biochemical Oxygen Demand, BOD), COD Cr , ammonia nitrogen ≤5 mg / L, total nitrogen ≤15 mg / L, total phosphorus ≤0.5 mg / L, color, etc., which are not limited in this embodiment.

[0079] In an optional embodiment, the effluent tank can be provided with one set of online monitoring instruments. When the online monitoring instruments pass the detection, the effluent tank directly discharges. When the online monitoring instruments fail the detection, the water in the effluent tank is lifted by a pump into the conditioning tank for secondary circulation treatment.

[0080] In this way, the pretreated nuclear power plant temporary wastewater is input into the reaction tank; in the reaction tank, the pH value of the pretreated wastewater is adjusted to a first target value, ferrous sulfate solution and hydrogen peroxide are sequentially added to form a first mixture; the first mixture is input into the sedimentation tank; in the sedimentation tank, the pH value of the first mixture is adjusted to a second target value, a coagulant and / or a coagulant aid are sequentially added to form a second mixture, and the second mixture includes a first suspension; the first suspension is input into a deep treatment device for deep treatment to form a first solution; the first solution is input into an effluent tank for disinfection treatment to form a second solution; and after the second solution meets the standard, the second solution is discharged. The second solution that meets the standard can be directly discharged into a river basin. It can be seen that, by using the nuclear power plant temporary wastewater treatment method provided in the application, the treatment effect can be improved.

[0081] Optionally, the nuclear power plant temporary wastewater treatment system further includes a sludge concentration tank, the sedimentation tank further includes a second output end, the second output end is in communication with the sludge concentration tank, and the second mixture further includes sludge.

[0082] The method further includes:

[0083] The sludge is input into the sludge concentration tank for concentration treatment.

[0084] The second mixture further includes sludge, i.e., sludge after the sludge-water separation treatment of the second mixture in the sedimentation zone of the sedimentation tank. The sludge is discharged into the sludge concentration tank through a sludge discharge pipe, and the sludge in the sludge concentration tank is lifted by a pump into a dewatering machine for treatment. The dewatered sludge can be transported out for disposal, and the dewatering machine filtrate is discharged into the conditioning tank for secondary circulation treatment.

[0085] In an alternative embodiment, the dewatering machine can be any one of a stack screw dewatering machine, a centrifugal dewatering machine, a plate-and-frame filter press, a belt dewatering machine, etc. In a specific implementation, the form of the dewatering machine can be selected according to the sludge disposal mode.

[0086] Optionally, the pre-treatment includes:

[0087] The temporary wastewater of the nuclear power plant to be treated is subjected to at least two-stage filtration treatment.

[0088] In this embodiment, by providing two-stage filtration treatment, the larger contaminant substances in the temporary wastewater of the nuclear power plant to be treated can be filtered out, thereby improving the treatment effect.

[0089] In an alternative embodiment, the pre-treatment device can be two grids with different intervals, so that the two grids are provided to remove the suspended particulate substances with larger particle sizes in the temporary wastewater of the nuclear power plant to be treated.

[0090] It should be understood that the first-stage filtration device can be a grid with a larger interval, and the second-stage filtration device can be a grid with a smaller interval. In this way, by providing the grids with different intervals, the suspended substances with different particle sizes can be filtered out, respectively.

[0091] Optionally, the reaction tank includes a first reaction tank and a second reaction tank, the output end of the adjusting tank is connected in communication with the input end of the first reaction tank, the output end of the first reaction tank is connected in communication with the input end of the second reaction tank, and the output end of the second reaction tank is connected in communication with the input end of the sedimentation tank.

[0092] The wastewater treated by the adjusting tank is lifted by a lifting pump to the first reaction tank, the pH value of the wastewater is adjusted to 3-3.5 by an acidic solution in the pH adjusting area of the first reaction tank, ferrous sulfate and hydrogen peroxide are sequentially added, so that the COD Cr , hydrazine, organic matter and other pollutants contained in the wastewater can be effectively removed; and after most of the pollutants are removed by the first reaction, the wastewater flows into the second reaction tank, ferrous sulfate and hydrogen peroxide are sequentially added in the second reaction tank, so that the COD Cr , hydrazine, organic matter and other pollutants in the wastewater are further removed.

[0093] In this embodiment, by providing two reaction tanks, the COD Cr , hydrazine, organic matter and other pollutants in the wastewater can be further removed, thereby improving the wastewater treatment effect.

[0094] Optionally, the temporary wastewater treatment system of the nuclear power plant further includes a chemical oxygen demand online monitoring instrument, an ammonia nitrogen online monitoring instrument, a total nitrogen online monitoring instrument and a total phosphorus online monitoring instrument arranged in the effluent tank.

[0095] In this embodiment, by setting up online monitoring instruments for chemical oxygen demand, ammonia nitrogen, total nitrogen, and total phosphorus, various indicators of the second solution can be detected online. After all indicators are found to be within acceptable limits, the second solution can be discharged into the watershed.

[0096] Optionally, in the sedimentation tank, the agent used to adjust the pH value includes at least one of calcium oxide, calcium hydroxide, and sodium hydroxide.

[0097] Optionally, the coagulant includes at least one of polyaluminum chloride, polyferric chloride, and polyferric sulfate;

[0098] The coagulant includes at least one of cationic polyacrylamide, anionic polyacrylamide, and nonionic polyacrylamide.

[0099] Optionally, the sedimentation tank is any one of the following: inclined tube sedimentation tank, inclined plate sedimentation tank, horizontal flow sedimentation tank, and radial flow sedimentation tank.

[0100] Optionally, the deep treatment device is any one of a sand filter, a quartz sand filter, or an activated carbon filter.

[0101] Optionally, the disinfection of the effluent pool can be achieved using any one of sodium hypochlorite, ozone, liquid chlorine, or chlorine dioxide.

[0102] To more clearly describe the process of the temporary wastewater treatment method for nuclear power plants provided in this application, the following detailed explanation of its operation process is provided in conjunction with a temporary wastewater treatment system for nuclear power plants.

[0103] like Figure 2 As shown, Figure 2 This is a flowchart illustrating the operation of the temporary wastewater treatment system for a nuclear power plant provided in this application. As shown in the figure, the temporary wastewater generated during the commissioning period of the nuclear power plant undergoes primary filtration treatment via a coarse screen, followed by secondary filtration treatment via a fine screen.

[0104] Wastewater that has undergone two filtration processes enters the equalization tank to adjust the water quality. The adjusted wastewater is then pumped to the primary reaction tank by a lift pump. The primary reaction tank is equipped with a sulfuric acid dosing system, a ferrous sulfate dosing system, and a hydrogen peroxide dosing system. The dosage of each of the three dosing systems is controlled by a metering pump.

[0105] After being treated in the primary reaction tank, the wastewater flows by gravity into the secondary reaction tank, which is equipped with a ferrous sulfate dosing system and a hydrogen peroxide dosing system. Both dosing systems control the dosage through metering pumps.

[0106] The wastewater is self-flowed into the sedimentation tank after being treated in the secondary reaction tank, and the sedimentation tank is also provided with three dosing systems, namely, an alkali dosing system, a coagulant dosing system and a coagulant aid dosing system. Similarly, the three dosing systems all control the amount of the reagent through the metering pump.

[0107] The supernatant after the treatment of the sedimentation tank is further input into the advanced treatment system for advanced treatment, and the wastewater after the advanced treatment is input into the effluent tank. A disinfectant dosing system is arranged in the effluent tank, and the disinfectant dosing system controls the amount of the reagent through the metering pump. The wastewater is disinfected in the effluent tank, and the wastewater that meets the treatment requirements is detected. The wastewater that meets the detection requirements is discharged to the river through the lifting pump, and the wastewater that does not meet the detection requirements is returned to the conditioning tank for secondary treatment.

[0108] The sludge after the treatment of the sedimentation tank is input into the sludge thickening tank for treatment. The supernatant in the sludge thickening tank is returned to the conditioning tank for secondary treatment, and the other part is dehydrated through the dewatering machine. Finally, the dewatered sludge is transported for treatment, and the filtrate is returned to the conditioning tank for secondary treatment.

[0109] It should be noted that the wastewater in the effluent tank can also be lifted to the advanced treatment system through the lifting pump to backwash the advanced treatment system, and the backwash water is returned to the conditioning tank for secondary treatment.

[0110] In addition, an overpass pipe is arranged between the conditioning tank and the sedimentation tank. That is, according to the water quality characteristics of the wastewater to be treated, the wastewater after the adjustment of the water quality in the conditioning tank can also be directly input into the sedimentation tank through the overpass pipe for related treatment without entering the primary reaction tank and the secondary reaction tank for treatment.

[0111] The application also provides an AP / CAP series temporary wastewater treatment method for nuclear power plants, which combines the above-mentioned AP / CAP series temporary wastewater treatment system and comprises the following steps. Figure 2 The method combines the temporary wastewater treatment system for the nuclear power plant and comprises the following steps.

[0112] (1) Pretreatment: the temporary wastewater during the debugging is treated through the coarse and fine grating and then input into the conditioning tank. The water quality and quantity of the wastewater are adjusted in the conditioning tank.

[0113] (2) Conditioning tank: the wastewater in the conditioning tank is lifted into the primary reaction tank through the pump. The pH adjustment area of the primary reaction tank controls the pH value of the wastewater to be 3-3.5 through the pH online detector and automatic dosing. After sufficient reaction of the sufficient ferrous sulfate and hydrogen peroxide, most of the pollutants such as COD, ammonia and organic matter in the wastewater can be removed, and the pollutants are converted into non-toxic and harmless small molecular substances such as nitrogen, carbon dioxide and water. When most of the pollutants such as COD, ammonia and organic matter in the wastewater meet the standard requirements, and only the suspended solids need to be removed, the wastewater can be directly input into the sedimentation tank through the overpass pipe for treatment. Cr Cr , ammonia and organic matter in the wastewater meet the standard requirements, and only the suspended solids need to be removed, the wastewater can be directly input into the sedimentation tank through the overpass pipe for treatment.​

[0114] (3) The primary reaction tank: the effluent of the primary reaction tank flows into the secondary reaction tank, and after sufficient reaction of the secondary reaction tank with sufficient ferrous sulfate and hydrogen peroxide, the pollutants such as hydrazine and organic matter in the wastewater can be further removed, and the pollutants such as COD, hydrazine and organic matter are converted into non-toxic and harmless small molecular substances such as nitrogen, carbon dioxide and water; Cr

[0115] (4) The secondary reaction tank: the effluent of the secondary reaction tank flows into the sedimentation tank, and the sludge and water are separated in the sedimentation tank. A pH adjusting area is arranged at the inlet of the sedimentation tank, and the pH value of the wastewater is controlled to be 7.5-8.5 through an on-line pH detector and automatic dosing. Then coagulants and coagulant aids are added in sequence, and after sufficient mixing, the wastewater flows into the sedimentation area, and the sludge and water are separated in the sedimentation area. The supernatant of the sedimentation tank flows into the advanced treatment device, and the sludge is discharged into the sludge thickening tank through a sludge discharge pipe. The pollutants such as suspended solids in the wastewater are removed. The sludge in the sedimentation tank is discharged into the sludge thickening tank, and the supernatant of the sludge thickening tank is discharged into the conditioning tank for treatment. The sludge in the sludge thickening tank is treated by a dewatering machine and then transported out for disposal. The filtrate of the dewatering machine is discharged into the conditioning tank for treatment.

[0116] (5) The advanced treatment device: the advanced treatment device further removes the pollutants such as suspended solids in the wastewater, and a backwashing system is arranged in the advanced treatment device.

[0117] (6) The effluent tank: the effluent tank is used for storing the water for backwashing of the advanced treatment device and temporarily storing the treated wastewater. An on-line monitoring instrument is arranged in the effluent tank. When the on-line monitoring instrument detects that the treated wastewater is qualified, the treated wastewater is directly discharged. When the on-line monitoring instrument detects that the treated wastewater is unqualified, the water in the effluent tank is pumped into the conditioning tank for treatment. An automatic disinfection system is arranged in the effluent tank, so that the residual chlorine of the discharged water is maintained at 2-4 mg / L.

[0118] The pretreatment system comprises two coarse and fine screens and a conditioning tank. The main function of the screens is to remove the suspended particulate matter with large particle size in the wastewater. The main function of the conditioning tank is to adjust the water quality and quantity of the wastewater. The adjusted wastewater is treated in sequence by the primary reaction tank, the secondary reaction tank, the sedimentation tank and the advanced treatment device. The pollutants such as COD, hydrazine and organic matter in the wastewater can be effectively degraded, and the pollutants such as COD, TN, TP, NH3-N and color in the treated wastewater can be stably regulated to meet the relevant discharge standards. In particular, the suspended solids are ≤20 mg / L, BOD5 is ≤10 mg / L, CODcr is ≤50 mg / L, ammonia nitrogen is ≤5 mg / L, total nitrogen is ≤15 mg / L, total phosphorus is ≤0.5 mg / L, and petroleum is ≤3 mg / L. Cr Cr

[0119] In the above step (2), the residence time of the primary reaction tank is 40-210 min.​​​

[0120] In this embodiment, the residence time of the secondary reaction tank is 35-135 min.

[0121] In this embodiment, the residence time of the sedimentation tank is 75-165 min.

[0122] In this embodiment, the residence time of the advanced treatment device is 0.5-4 h.

[0123] In this embodiment, the residence time of the effluent tank is 1-4 h.

[0124] The temporary wastewater treatment process during the commissioning of a nuclear power plant provided in this embodiment is that the wastewater sequentially passes through a pretreatment system, a primary reaction tank, a secondary reaction tank, a sedimentation tank, an advanced treatment device, and a disinfection treatment. The COD Cr , hydrazine, NH3-N, organic matter and other pollutant substances in the temporary wastewater generated during the commissioning can be effectively degraded, and the COD Cr , BOD5, TN, TP, color and other pollutant substances in the treated wastewater can stably reach the provisions of the relevant discharge standards. Moreover, the treatment efficiency is high, the cost is low, and the operation and management are simple.

[0125] The present embodiment will be further described below by means of examples and in conjunction with the accompanying drawings:

[0126] The water quality of the temporary wastewater of the AP / CAP series nuclear power plant during the commissioning is shown in Table 1.

[0127] Table 1 Main water quality indexes of the influent

[0128] Category COD Cr ]] Hydrazine Ammonia nitrogen Influent water quality 175 162 0.01

[0129] As shown in Figure 2 , a temporary wastewater treatment method for the AP / CAP series nuclear power plant during the commissioning comprises a coarse grid 1, a fine grid 2, a conditioning tank 3, a primary reaction tank 4, a secondary reaction tank 5, a sedimentation tank 6, an advanced treatment device 7, an effluent tank 8, a sludge thickening tank 9, a dewatering machine 10, and corresponding dosing systems, pipelines and the like.

[0130] The temporary wastewater during the commissioning is intercepted by the coarse grid 1 and the fine grid 2 after the interception of large suspended solids, and then enters the conditioning tank 3 to adjust the water quality and quantity of the wastewater. The effluent of the conditioning tank 3 is lifted by a pump and enters the primary reaction tank 4, effectively removing most of the COD Cr , hydrazine, organic matter and other pollutant substances in the wastewater. The residence time in the primary reaction tank 4 is 150 min.

[0131] The effluent of the primary reaction tank 4 enters the secondary reaction tank 5, further removing the COD Cr , hydrazine, organic matter and other pollutant substances contained in the wastewater. The residence time in the secondary reaction tank 5 is 90 min.

[0132] The effluent from the secondary reaction tank 5 flows into the sedimentation tank 6 by itself, and after the sludge and water are separated, the supernatant of the sedimentation tank 6 flows into the advanced treatment device to further remove the suspended solids contained in the wastewater; the sludge in the sedimentation tank 6 flows into the sludge thickening tank 9, the supernatant of the sludge thickening tank flows into the conditioning tank 3 for treatment, the sludge in the sludge thickening tank 9 is treated by the dewatering machine 10 and then is transported out for disposal, and the filtrate of the dewatering machine 10 flows into the conditioning tank for treatment.

[0133] The effluent from the advanced treatment device 7 flows into the effluent tank 8 by itself, and a disinfectant is added in the effluent tank 8.

[0134] After the water is treated by the above process units, the pollutants such as COD Cr , ammonia nitrogen and the like in the wastewater are shown in Table 2.

[0135] Table 2 Main effluent water quality indexes

[0136] Category COD Cr ]] Hydrazine Ammonia nitrogen Effluent water quality 8 0.01 0.03

[0137] That is, the water quality after treatment can stably reach the provisions of the relevant discharge standards. It should be noted that the pH online detector is arranged in the pH adjustment area and the effluent tank.

[0138] The nuclear power plant temporary wastewater treatment process provided in the embodiment includes the coarse and fine grids and the conditioning tank connected in sequence, the effluent from the conditioning tank is lifted by a pump and then flows into the primary reaction tank, the effluent from the primary reaction tank flows into the secondary reaction tank by itself, the effluent from the secondary reaction tank flows into the advanced treatment device after being precipitated, the effluent from the advanced treatment device flows into the effluent tank, the wastewater in the effluent tank is disinfected and then is discharged up to the standard, and the effluent can stably reach the provisions of the relevant discharge standards of the pollutants such as COD Cr , BOD5, TN, TP and colority. It can be seen that the wastewater treatment method provided in the application has good treatment effect. Moreover, compared with other processes, the treatment technology has the characteristics of low energy consumption, low operation cost and low capital cost.

[0139] The nuclear power plant temporary wastewater treatment device provided in the embodiment includes the nuclear power plant temporary wastewater treatment system, and the nuclear power plant temporary wastewater treatment system further includes the conditioning tank, the reaction tank, the sedimentation tank, the advanced treatment device and the effluent tank.

[0140] The nuclear power plant temporary wastewater treatment device is used for:

[0141] The pretreated nuclear power plant temporary wastewater is input from the adjusting tank to the reaction tank;

[0142] In the reaction tank, the pH value of the pretreated wastewater is adjusted to a first target value, and ferrous sulfate solution and hydrogen peroxide are sequentially added to form a first mixture;

[0143] The first mixture is input to the precipitation tank;

[0144] In the precipitation tank, the pH value of the first mixture is adjusted to a second target value, and a coagulant and / or a coagulant aid are sequentially added to form a second mixture, the second mixture comprising a first suspension;

[0145] The first suspension is input to a deep treatment device for deep treatment to form a first solution;

[0146] The first solution is input to a water outlet tank for disinfection treatment to form a second solution;

[0147] After detecting that the second solution meets the standard, the second solution is discharged;

[0148] The first target value is less than the second target value, and the first target value is an acidic value and the second target value is an alkaline value.

[0149] Optionally, the nuclear power plant temporary wastewater treatment system further comprises a sludge concentration tank, and the precipitation tank further comprises a second output end, the second output end being in communication with the sludge concentration tank, and the second mixture further comprising sludge;

[0150] The nuclear power plant temporary wastewater treatment device is further used for:

[0151] The sludge is input to the sludge concentration tank for concentration treatment.

[0152] Optionally, the pretreatment comprises:

[0153] The nuclear power plant temporary wastewater to be treated is subjected to at least two stages of filtration treatment.

[0154] Optionally, the reaction tank comprises a primary reaction tank and a secondary reaction tank, the output end of the adjusting tank being in communication with the input end of the first reaction tank, the output end of the primary reaction tank being in communication with the input end of the secondary reaction tank, and the output end of the secondary reaction tank being in communication with the input end of the precipitation tank.

[0155] Optionally, the nuclear power plant temporary wastewater treatment system further comprises a chemical oxygen demand online monitoring instrument, an ammonia nitrogen online monitoring instrument, a total nitrogen online monitoring instrument, and a total phosphorus online monitoring instrument arranged in the water outlet tank.

[0156] Optionally, in the sedimentation tank, the pH adjusting agent comprises at least one of calcium oxide, calcium hydroxide, and sodium hydroxide.

[0157] Optionally, the coagulant comprises at least one of polyaluminum chloride, polyferric chloride, and polyferric sulfate.

[0158] The coagulant aid comprises at least one of cationic polyacrylamide, anionic polyacrylamide, and nonionic polyacrylamide.

[0159] Optionally, the sedimentation tank is any one of a lamella sedimentation tank, a inclined plate sedimentation tank, a horizontal flow sedimentation tank, and a radial flow sedimentation tank.

[0160] and / or,

[0161] The advanced treatment device is any one of a sand filter, a quartz sand filter, and an activated carbon filter.

[0162] Optionally, the disinfection of the effluent tank uses any one of sodium hypochlorite, ozone, liquid chlorine, and chlorine dioxide.

[0163] The embodiments of the application are described above with reference to the accompanying drawings, but the application is not limited to the specific embodiments described above, which are merely illustrative rather than restrictive, and a person of ordinary skill in the art can make many forms under the inspiration of the application without departing from the scope of the application and the scope protected by the claims.

Claims

1. A method for treating temporary wastewater from a nuclear power plant, applied to a temporary wastewater treatment system for a nuclear power plant, characterized in that, The temporary wastewater treatment system of the nuclear power plant includes an equalization tank, a reaction tank, a sedimentation tank, an advanced treatment device, and an effluent tank. The output end of the equalization tank is connected to the input end of the reaction tank, the output end of the reaction tank is connected to the input end of the sedimentation tank, the sedimentation tank includes a first output end, the first output end is connected to the input end of the advanced treatment device, and the output end of the advanced treatment device is connected to the effluent tank. The method includes: Pretreated temporary wastewater from the nuclear power plant is fed from the equalization tank into the reaction tank; In the reaction tank, the pH value of the pretreated wastewater is adjusted to the first target value, and ferrous sulfate solution and hydrogen peroxide are added in sequence to form a first mixture; The first mixture is fed into the sedimentation tank; In the sedimentation tank, the pH value of the first mixture is adjusted to a second target value, and coagulant and / or coagulant aid are added sequentially to form a second mixture, the second mixture comprising the first suspension; The first suspension is fed into a deep processing device for deep processing to form a first solution; The first solution is fed into the effluent tank for disinfection to form the second solution; After the second solution is tested and found to meet the standards, the second solution is discharged. Wherein, the first target value is less than the second target value, and the first target value is an acidic value, while the second target value is an alkaline value.

2. The method according to claim 1, characterized in that, The temporary wastewater treatment system of the nuclear power plant also includes a sludge thickening tank, and the sedimentation tank also includes a second output end, which is connected to the sludge thickening tank. The second mixture also includes sludge. The method further includes: The sludge is fed into the sludge thickening tank for thickening treatment.

3. The method according to claim 1, characterized in that, The preprocessing includes: The temporary wastewater from the nuclear power plant to be treated will undergo at least two stages of filtration.

4. The method according to claim 1, characterized in that, The reaction tank includes a primary reaction tank and a secondary reaction tank. The output end of the equalization tank is connected to the input end of the primary reaction tank, the output end of the primary reaction tank is connected to the input end of the secondary reaction tank, and the output end of the secondary reaction tank is connected to the input end of the sedimentation tank.

5. The method according to claim 1, characterized in that, The temporary wastewater treatment system for the nuclear power plant also includes online monitoring instruments for chemical oxygen demand, ammonia nitrogen, total nitrogen, and total phosphorus, which are installed in the effluent pool.

6. The method according to claim 1, characterized in that, In the sedimentation tank, the agent used to adjust the pH value includes at least one of calcium oxide, calcium hydroxide, and sodium hydroxide.

7. The method according to claim 1, characterized in that, The coagulant includes at least one of polyaluminum chloride, polyferric chloride, and polyferric sulfate; The coagulant includes at least one of cationic polyacrylamide, anionic polyacrylamide, and nonionic polyacrylamide.

8. The method according to claim 1, characterized in that, The sedimentation tank is any one of the following: inclined tube sedimentation tank, inclined plate sedimentation tank, horizontal flow sedimentation tank, and radial flow sedimentation tank. And / or, The advanced treatment device can be any one of a sand filter, a quartz sand filter, or an activated carbon filter.

9. The method according to claim 1, characterized in that, The effluent pool is disinfected using any one of sodium hypochlorite, ozone, liquid chlorine, or chlorine dioxide.

10. A temporary wastewater treatment device for a nuclear power plant, comprising the aforementioned temporary wastewater treatment system, characterized in that, The temporary wastewater treatment system of the nuclear power plant also includes an equalization tank, a reaction tank, a sedimentation tank, a deep treatment device, and an effluent tank. The output end of the equalization tank is connected to the input end of the reaction tank, the output end of the reaction tank is connected to the input end of the sedimentation tank, the sedimentation tank includes a first output end, the first output end is connected to the input end of the deep treatment device, and the output end of the deep treatment device is connected to the effluent tank. The temporary wastewater treatment device at the nuclear power plant is used for: Pretreated temporary wastewater from the nuclear power plant is fed from the equalization tank into the reaction tank; In the reaction tank, the pH value of the pretreated wastewater is adjusted to the first target value, and ferrous sulfate solution and hydrogen peroxide are added in sequence to form a first mixture; The first mixture is fed into the sedimentation tank; In the sedimentation tank, the pH value of the first mixture is adjusted to a second target value, and coagulant and / or coagulant aid are added sequentially to form a second mixture, the second mixture comprising the first suspension; The first suspension is fed into a deep processing device for deep processing to form a first solution; The first solution is fed into the effluent tank for disinfection to form the second solution; After the second solution is tested and found to meet the standards, the second solution is discharged. Wherein, the first target value is less than the second target value, and the first target value is an acidic value, while the second target value is an alkaline value.

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