System for treating and recycling sludge drying and condensing wastewater of power plant

Abstract

The utility model relates to the technical field of wastewater treatment and reuse, and discloses a power plant sludge drying condensation wastewater treatment and reuse system, which comprises an adjusting tank, a heat exchanger, an air flotation machine, a hydrolysis acidification tank, at least one A / O unit and a flocculation sedimentation tank which are sequentially arranged along the wastewater flowing direction, each A / O unit comprises an A / O reaction tank and a sedimentation tank, the A / O reaction tank comprises an anoxic tank and an aerobic tank, the anoxic tank, the aerobic tank and the sedimentation tank are sequentially arranged along the flowing direction of wastewater, and filler for attachment of microorganisms is arranged in the aerobic tank. According to the system provided by the utility model, an A / O method and a biological contact oxidation method are combined together, so that the process treatment capacity is large, the sludge generation amount is small, sludge bulking cannot be generated in the operation process, the stability of the effluent quality can be ensured, the one-time investment and the operation cost can be reduced, and the occupied area is reduced; the system can effectively remove suspended matters, COD (Chemical Oxygen Demand), ammonia nitrogen, total phosphorus and the like in the sludge drying and condensing wastewater, and effluent reaching the standard can be recycled to a power plant.

Description

Technical Field

[0001] The utility model relates to the technical field of wastewater treatment and reuse, in particular to a system for treating and reusing sludge drying and condensing wastewater from a power plant. Background Art

[0002] After natural or artificial dehydration, the moisture content of sludge is generally 60% to 80%. Due to this high moisture content, it is difficult to meet the requirements of subsequent disposal such as composting, landfill, and incineration. Usually, technical means are needed to reduce the moisture content. Sludge drying is an effective means to reduce the moisture content of sludge.

[0003] The water in wet sludge, with a moisture content of 60% to 80%, primarily consists of capillary water, adsorbed water, and internal water. Sludge drying can further remove this capillary water, reducing the sludge moisture content to 10% to 30%. This capillary water escapes as water vapor during drying and condenses back into liquid water, forming dried condensate wastewater. Compared to standard domestic sewage, this condensate wastewater has higher pollutant concentrations, a nutrient content unfavorable for biochemical treatment, and a higher water temperature. Its quality fluctuates significantly depending on the dried sludge source, storage time, drying temperature, and drying process.

[0004] The current method of treating dried condensate wastewater requires a large amount of carbon source reagents to be added at the front-end biochemical treatment end; some processes do not have deep treatment processes at the back end, and the concentration of pollutants in the effluent water is still high. After treatment, it is discharged into the municipal pipeline again and does not meet the reuse standards; or the back-end deep treatment uses membrane or adsorption methods and other processes to meet the reuse standards, but it will cause secondary pollution problems such as concentrated water and saturated adsorbent. Utility Model Content

[0005] The purpose of this utility model is to overcome the problems existing in the prior art and provide a system for treating and reusing power plant sludge drying and condensing wastewater, which is cost-effective, environmentally friendly and has good effluent quality, thereby achieving the requirements of harmless treatment, resource utilization and even reuse of sludge drying and condensing wastewater.

[0006] In order to achieve the above-mentioned object, the utility model provides a system for treating and reusing sludge drying and condensing wastewater from a power plant, the system comprising a regulating tank, a heat exchanger, an air flotation machine, a hydrolysis and acidification tank, at least one A / O unit, and a flocculation and sedimentation tank, which are sequentially arranged along the flow direction of the wastewater;

[0007] Among them, each A / O unit includes an A / O reaction tank and a sedimentation tank, the A / O reaction tank includes an anoxic tank and an aerobic tank, the anoxic tank, aerobic tank and sedimentation tank are arranged in sequence along the flow direction of the wastewater, and the aerobic tank is provided with fillers for microorganisms to attach.

[0008] Preferably, the aerobic pool is provided with power plant slag fillers and soft fillers.

[0009] Preferably, the system further comprises a blower, a cyclone aerator is provided in the aerobic tank, and the blower is connected to the cyclone aerator.

[0010] Preferably, a stirrer is provided in the anoxic tank.

[0011] Preferably, the sludge outlet of the sedimentation tank is connected to the A / O reaction tank.

[0012] Preferably, the system further comprises a disinfection tank, which is connected to the water outlet of the flocculation sedimentation tank.

[0013] Preferably, the system further comprises a shallow sand filter connected to the outlet of the disinfection tank.

[0014] Preferably, the system further comprises a sludge thickening tank, which is connected to the flotation machine, the sedimentation tank and the flocculation sedimentation tank.

[0015] Preferably, the system further comprises a snail stacking machine, which is connected to the sludge outlet of the sludge thickening tank.

[0016] Preferably, the number of the A / O units is 2, and the two A / O units are arranged in series.

[0017] Through the above technical solution, the beneficial technical effects achieved by the utility model are as follows:

[0018] (1) The system provided by the utility model can effectively remove suspended solids, COD, ammonia nitrogen, total phosphorus, etc. in sludge drying and condensation wastewater. The effluent that meets the standards can be used as water for circulating cooling towers in power plants, water for desulfurization process, or direct current cooling water for power plants.

[0019] (2) The system provided by the present invention has a system in which the structures can be reused during operation, and the equipment operation and maintenance costs are low.

[0020] (3) In the technical solution provided by the present invention, the chemicals and equipment used in the wastewater treatment process are all conventional chemicals and equipment sold on the market, and the system configuration is simple.

[0021] (4) The entire system does not contain saturated adsorbent and concentrated water, so there is less secondary pollution problem and it can be utilized as a resource.

[0022] (5) In the present invention, by setting up a hydrolysis and acidification tank, the biodegradability of the sludge drying and condensation wastewater is improved, the amount of carbon source added in the biochemical stage is reduced, and the operating cost is reduced;

[0023] (6) The system provided by the present invention can combine the A / O method with the biological contact oxidation method by arranging fillers in the aerobic tank. The biological contact oxidation tank is no longer a separate process flow, but serves as the main operating unit of the aerobic process (O section). The process has a large processing capacity, a small amount of sludge generated, and no sludge expansion occurs during operation, which can ensure the stability of the effluent water quality. At the same time, since the process combines the advantages of both the activated sludge method and the biofilm method, it can reduce one-time investment and operating costs, reduce the floor space, and is easy to manage and resistant to load shock.

[0024] (7) Using power plant slag as filler and using local materials can reduce transportation and storage costs and realize waste resource utilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a structural diagram of an embodiment of a system for treating and reusing power plant sludge drying and condensation wastewater provided by the utility model;

[0026] Figure 2 yes Figure 1 Schematic diagram of the structure of the A / O reaction pool.

[0027] Description of Reference Numerals

[0028] 1-equalization tank; 2-heat exchanger; 3-flotation machine; 4-hydrolysis acidification tank; 5-A / O unit; 51-A / O reaction tank; 511-anoxic tank; 5111-mixer; 512-aerobic tank; 5121-power plant slag filler; 5122-soft filler; 5123-filler bracket; 5124-cyclone aerator; 5125-air pipe; 52-sedimentation tank; 6-flocculation sedimentation tank; 7-blower; 8-disinfection tank; 9-drainage tank; 10-shallow sand filter; 11-sludge thickening tank; 12-screw stacker. DETAILED DESCRIPTION

[0029] The following is a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0030] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0031] The utility model provides a system for treating and reusing sludge drying and condensation wastewater from power plants. Figure 1 and Figure 2 The system includes a regulating tank 1, a heat exchanger 2, an air flotation machine 3, a hydrolysis acidification tank 4, at least one A / O unit 5, and a flocculation sedimentation tank 6, which are arranged in sequence along the flow direction of the wastewater;

[0032] Among them, each of the A / O units 5 includes an A / O reaction tank 51 and a sedimentation tank 52, the A / O reaction tank 51 includes an anoxic tank 511 and an aerobic tank 512, the anoxic tank 511, the aerobic tank 512 and the sedimentation tank 52 are arranged in sequence along the flow direction of the wastewater, and the aerobic tank 512 is provided with a filler for microorganisms to attach.

[0033] The present invention does not limit the specific form of the A / O reaction tank 51 and can be designed according to actual working conditions. For example, the A / O reaction tank 51 can be a tank body, which is divided into an anoxic tank 511 and an aerobic tank 512 by structures such as partitions; the A / O reaction tank 51 can also be two connected tank bodies, one of which is an anoxic tank 511 and the other is an aerobic tank 512.

[0034] In the present invention, the power plant sludge drying and condensation wastewater is specifically the sludge drying and condensation wastewater of a thermal power plant.

[0035] In a specific embodiment, the system further includes a sludge thickening tank 11 for thickening the sludge in the system.

[0036] In the present invention, heat exchanger 2 is provided to cool the wastewater, facilitating the growth and activity of microorganisms in the subsequent biochemical stage (A / O unit 5). The present invention is not limited to the specific type of heat exchanger 2; it may be any commonly used heat exchanger in the art. In one specific embodiment, heat exchanger 2 is a plate heat exchanger 2. Wastewater from the regulating tank 1 exchanges heat with the cooling circulating water in the plate heat exchanger 2 to cool the wastewater.

[0037] In the system described in the present invention, the flotation machine 3 is provided to remove suspended solids from wastewater using a flotation process. Specifically, the dissolved air flotation machine 3 is a type of flotation, designed to remove suspended solids, grease, and various colloids from various wastewaters. By utilizing the different solubility properties of water at different pressures, partially treated water is pressurized and aerated to increase the amount of air dissolved in the water. By adding PAC (polyaluminum chloride) / PAM (polyacrylamide) to the water and releasing it under normal pressure, air is precipitated to form small bubbles that adhere to impurity flocs, causing the overall density of the flocs to be less than that of water, causing them to rise, thereby achieving solid-liquid separation and removing suspended solids from the wastewater.

[0038] In a specific embodiment, the suspended matter in the flotation machine 3 is discharged into the sludge thickening tank 11 .

[0039] In the system described in the present invention, the biodegradability of the wastewater can be improved by setting up a hydrolysis acidification tank 4. Specifically, the hydrolysis (acidification) treatment method is a method between aerobic and anaerobic treatment methods, and its combination with other processes can reduce treatment costs and improve treatment efficiency. The hydrolysis acidification process controls the anaerobic treatment to the first and second stages of anaerobic treatment with shorter reaction times based on the different growth rates of methanogens and hydrolytic acidogenic bacteria. That is, under the action of a large number of hydrolytic bacteria and acidifying bacteria, insoluble organic matter is hydrolyzed into soluble organic matter, and difficult-to-biodegrade macromolecular substances are converted into easily biodegradable small molecular substances, thereby improving the biodegradability of the wastewater and laying a good foundation for subsequent biochemical treatment.

[0040] In the system described in this utility model, the biochemical reaction process is an A / O unit 5 (A / O process + biological contact oxidation). This utility model combines the A / O process with the biological contact oxidation process. The biological contact oxidation tank is no longer a separate process flow, but instead serves as the main operating unit of the aerobic process (O stage). It consists of four parts: the tank body, filler, and water and gas distribution systems. Wastewater and return sludge simultaneously enter the anoxic tank 511 (A tank) and, after a short residence time, flow into the aerobic tank 512 (O tank).

[0041] The system described in the utility model combines the A / O method with the biological contact oxidation method, has a large process processing capacity, and the CODCr volume load can reach 1.5-2.5kg / m 3 d. CODCr removal rate exceeds 80%, sludge generation is minimal, and sludge yield is 0.2-0.4 kg dry sludge / kg CODCr. Sludge bulking does not occur during operation, ensuring stable effluent quality. Because this process combines the advantages of both activated sludge and biofilm processes, it can reduce one-time investment and operating costs, minimize floor space, and is easy to manage and resistant to load shocks.

[0042] The fiber-type soft filler used in the conventional biological contact oxidation method has a large theoretical specific surface area, is easy to form a film, has a low cost, saves on freight, is easy to assemble, is not blocked, but is prone to broken wires and center rope breakage, and has a service life of only 1-2 years. In order to improve the service life of the filler in the aerobic tank 512 and save costs, in a preferred embodiment, the aerobic tank 512 is internally provided with a power plant slag filler 5121 and a soft filler 5122 (fiber-type soft filler). The power plant slag has a large specific surface area and is porous, which can provide space for biological attachment, and the use of power plant slag as filler, which is locally sourced, can reduce transportation and storage costs and realize waste resource utilization. In this embodiment, the process of combining the soft filler 5122 and the power plant slag filler 5121 can, on the one hand, make up for the defect of the low service life of the soft filler, and on the other hand, realize the resource utilization of the power plant slag, thereby making the operating cost of the system low.

[0043] In a specific embodiment, in the aerobic pool 512 , the ratio of the soft filler 5122 to the power plant slag filler 5121 is 1 to 3:1, preferably 2:1.

[0044] In the present invention, the system further includes a blower 7. A cyclone aerator 5124 is provided in the aerobic tank 512. The blower 7 is connected to the cyclone aerator 5124 via an air pipe 5125 to provide oxygen required for the survival of microorganisms in the aerobic tank 512 in the biochemical section.

[0045] In a specific embodiment, the filler is disposed in the aerobic tank 512 via a filler support 5123 and is located in the upper middle portion of the aerobic tank 512 , and the cyclone aerator 5124 is disposed at the bottom of the aerobic tank 512 .

[0046] In a specific embodiment, the power plant slag filler 5121 and the soft filler 5122 are arranged in sequence along the direction of wastewater flow.

[0047] In a preferred embodiment, a mixer 5111 is provided in the anoxic tank 511. The mixer can better contact the wastewater with the microorganisms, thereby enhancing the treatment effect. In a specific embodiment, the mixer 5111 is a submersible mixer.

[0048] In a preferred embodiment, the sludge outlet of the sedimentation tank 52 is connected to the A / O reaction tank 51 and the sludge thickening tank 11, so that part of the sludge in the sedimentation tank 52 is recycled to the A / O reaction tank 51, and the remaining sludge is discharged into the sludge thickening tank 11 for concentration.

[0049] In a specific embodiment, part of the sludge in the sedimentation tank 52 is specifically recycled to the anoxic tank 511 (A tank) in the A / O reaction tank.

[0050] In the present invention, the effluent from the A / O unit 5 flows by gravity into a flocculation sedimentation tank 6, where suspended solids in the wastewater are removed by precipitation with the addition of a drug. In specific implementation, an inorganic flocculant and an organic anionic flocculant, polyacrylamide (PAM), are selected and formulated into an aqueous solution and added to the wastewater. This produces a compressed double layer, causing the suspended particles in the wastewater to lose stability. The colloids agglomerate with each other, causing the particles to increase in size, forming flocs and alum flowers. Once the flocs grow to a certain volume, they precipitate out of the aqueous phase under the action of gravity, thereby removing a large amount of suspended solids in the wastewater and achieving the desired water treatment effect. The inorganic flocculant can be polyaluminum chloride (PAC), polyferric sulfate, polyaluminum ferric chloride, ferrous sulfate, or basic aluminum chloride. The wastewater treated in the flocculation sedimentation tank 6 can meet discharge standards in terms of color and suspended solids content.

[0051] In a specific embodiment, the reagents added to the flocculation sedimentation tank 6 are PAC and PAM. In order to improve the separation effect, a coagulant aid can also be added.

[0052] In a specific embodiment, the sludge outlet of the flocculation sedimentation tank 6 is connected to the sludge thickening tank 11. In a specific implementation, the sludge in the flocculation sedimentation tank 6 is discharged into the sludge thickening tank 11 through a sludge pump.

[0053] In a specific embodiment, the system may further include a disinfection tank 8, which is connected to the outlet of the flocculation sedimentation tank 6 and is used to disinfect the effluent from the flocculation sedimentation tank 6, thereby further killing harmful pathogenic microorganisms in the wastewater and preventing the spread of disease.

[0054] The present invention is not limited to a specific disinfection method, and can be a commonly used disinfection method in the art, such as chlorination, ozone disinfection, sodium hypochlorite disinfection, chlorine dioxide disinfection, etc. In a specific embodiment of the present invention, sodium hypochlorite is added to the disinfection tank 8.

[0055] In a preferred embodiment, the system further includes a shallow sand filter 10 connected to the outlet of the disinfection tank 8 and configured to filter the effluent from the disinfection tank 8 to further improve the effluent quality. The shallow sand filter 10, also known as a fully automatic shallow sand filter 10, is a finished device with a high flow rate and no maintenance. The present invention utilizes the shallow sand filter 10 for filtration, achieving good results at a low cost.

[0056] In a specific embodiment, the system may further include a snail stacking machine 12, which is connected to the sludge outlet of the sludge thickening tank 11 and is used to dewater the sludge from the sludge thickening tank 11. The dewatered water enters the ditch and then flows into the regulating tank 1. The dewatered sludge can be sent to the plant sludge drying system for further disposal.

[0057] The present invention does not limit the specific number of the A / O units 5, and can be 1, 2, 3, 4, or 5. In a preferred embodiment, the number of the A / O units 5 is 2, and the two A / O units 5 are arranged in series. By adopting a two-stage A / O treatment process, the wastewater treatment effect is improved, the treatment cost is reduced, and the treatment time is shortened. That is, in this embodiment, the number of the anoxic tank 511, the aerobic tank 512, and the sedimentation tank 52 are all 2.

[0058] In a specific embodiment of the present invention, the process of treating power plant sludge drying and condensation wastewater using the system described in the present invention includes:

[0059] The condensed wastewater generated by sludge drying flows by gravity into the regulating tank 1 for homogenization and equalization; a submerged mixer is installed in the regulating tank 1 to prevent sludge deposition; the temperature of the dried condensed wastewater is ≥55°C. The high water temperature affects the growth of microorganisms in the subsequent biochemical stage and needs to be cooled; the sludge drying condensed wastewater in the regulating tank 1 is pumped to the plate heat exchanger 2 for heat exchange, and the temperature of the wastewater after treatment by the heat exchanger 2 is ≤36°C; after cooling, the wastewater is subjected to air flotation in the flotation machine 3 to remove suspended solids in the wastewater; the flotation effluent flows by gravity into the hydrolysis and acidification tank 4, where the organic matter in the wastewater is hydrolyzed to improve the biodegradability of the wastewater. A submerged mixer is installed in the hydrolysis and acidification tank 4; the water The deacidified effluent passes through the two-stage A / O unit 5 (specifically, passes through the A / O reaction tank 51, the sedimentation tank 52, the A / O reaction tank 51 and the sedimentation tank 52 in sequence) to remove pollutants such as organic matter and ammonia nitrogen in the wastewater; among them, a submersible mixer is set in the A tank and a liftable cyclone aerator 5124 is set in the O tank; the two-stage A / O reaction tank 51 is respectively provided with nitrification liquid reflux denitrification, and alkali and carbon source are added to ensure the alkalinity of the wastewater and a reasonable carbon-nitrogen ratio; the effluent from the sedimentation tank 52 downstream of the two-stage A / O unit 5 enters the flocculation sedimentation tank 6, and the suspended matter in the wastewater is removed by precipitation with the addition of drugs; the effluent from the flocculation sedimentation tank 6 enters the drainage tank 9 after disinfection for discharge or reuse. A shallow sand filter 10 is installed after the external discharge pump to ensure that the recycled water SS meets the standard; after meeting the standard, the water can be used as desulfurization process water replenishment in the power plant, circulating cooling tower replenishment water or direct cooling water in the power plant; the backwash water of the shallow sand filter 10 can flow into the ditch by gravity and then into the regulating tank 1;

[0060] The suspended matter separated by the flotation machine 3 is discharged into the sludge thickening tank 11; the sludge in the flocculation sedimentation tank 6 is discharged into the sludge thickening tank 11 through the sludge pump; both sedimentation tanks 52 are equipped with a power pump, which can serve as a sludge return pump to return part of the sludge in the sedimentation tank 52 to tank A through the sludge return pump, and can also serve as a sludge discharge pump to discharge the remaining sludge into the sludge thickening tank 11; the sludge in the thickening tank is concentrated and pressurized by the pump and enters the screw press 12 for dehydration. The dehydrated water enters the ditch and then merges into the regulating tank 1. The dehydrated sludge is sent to the plant sludge drying system for further disposal.

[0061] Through the above technical solution, the system provided by the utility model has the following advantages when used to treat sludge drying and condensing wastewater from power plants: 1. The process flow is short and can effectively remove suspended solids, COD, ammonia nitrogen, total phosphorus, etc. in sludge drying and condensing wastewater, with low overall investment cost and low operating cost; 2. The reagents used in this treatment method are conventional reagents sold on the market, and there is no need to use extreme conditions to prepare or difficult to purchase reagents, and it can cope with the treatment of different types of sludge drying and condensing wastewater; 3. The entire system has no saturated adsorbents and concentrated water, with few secondary pollution problems and resource utilization; 4. The entire system has a high degree of mechanization, simple operation, and convenient operation and management; 5. This process adopts a combination of flotation-hydrolysis acidification-two-stage A / O+biological contact oxidation-flocculation sedimentation-disinfection-shallow sand filtration-reuse in the power plant; 6. The treated dried condensing wastewater can be reused in the power plant, which saves water on the one hand. On the one hand, it saves resources, and on the other hand, it reduces the amount of wastewater discharged into the municipal pipe network, which reduces the operating pressure of the sewage treatment plant to a certain extent; 7. The biodegradability of the sludge drying and condensation wastewater is improved through the hydrolysis and acidification process, which reduces the amount of carbon source added in the biochemical stage and reduces the operating cost; 8. The A / O method is combined with the biological contact oxidation method. The biological contact oxidation tank is no longer a separate process flow, but is the main operating unit of this aerobic process (O stage). The biological contact oxidation tank is used as the main operating unit of this aerobic process (O stage). The process has a large processing capacity, a small amount of sludge generated, and no sludge swelling occurs during operation, which can ensure the stability of the effluent water quality. Since this process combines the advantages of both the activated sludge method and the biofilm method, it can reduce one-time investment and operating costs, reduce the floor space, and is easy to manage and resistant to load shocks; 9. The use of power plant slag as filler, using local materials, can reduce transportation and storage costs and realize waste resource utilization.

[0062] The present invention will be described in detail below through examples, but the scope of protection of the present invention is not limited thereto. The experimental methods in the following examples, unless otherwise specified, are conventional methods in the art. The experimental materials used in the following examples, unless otherwise specified, are all commercially available products.

[0063] In the following examples and comparative examples, the sludge drying condensate wastewater to be treated is simulated wastewater designed based on the conventional water quality of condensate wastewater generated by sludge drying in thermal power plants, and its pollutant content is shown in Table 1 below.

[0064] Table 1

[0065]

[0066]

[0067] Example 1

[0068] use Figure 1The system for treating and reusing power plant sludge drying and condensation wastewater shown in the figure performs the operation of this embodiment.

[0069] The system includes a regulating tank 1, a heat exchanger 2, an air flotation machine 3, a hydrolysis acidification tank 4, two A / O units 5, a flocculation sedimentation tank 6, a disinfection tank 8, a drainage tank 9 and a shallow sand filter 10, which are connected in sequence along the flow direction of the wastewater;

[0070] Among them, two A / O units 5 are arranged in series, and each A / O unit 5 includes an A / O reaction pool 51 (such as Figure 2 As shown) and a sedimentation tank 52, the A / O reaction tank 51 includes an anoxic tank 511 (A tank) and an aerobic tank 512 (O tank). In each A / O unit 5, the anoxic tank 511, the aerobic tank 512 and the sedimentation tank 52 are arranged in sequence along the flow direction of the wastewater. A soft filler 5122 and a power plant slag filler 5121 are provided inside the O tank. The usage ratio of the soft filler 5122 to the power plant slag filler 5121 is 2:1. The arrangement is such that the wastewater first passes through the power plant slag filler 5121 and then passes through the soft filler 5122; a liftable cyclone aerator 5124 is provided in the O tank, and a blower 7 is connected to the cyclone aerator 5124 through an air pipe 5125 to provide the microorganisms in the O tank with oxygen required for survival;

[0071] The system also includes a sludge thickening tank 11 and a screw stacker 12 connected in sequence. The sludge outlet of the sedimentation tank 52 is connected to the A / O reaction tank 51 and the sludge thickening tank 11 respectively. The sludge outlet of the flotation machine 3 and the sludge outlet of the flocculation sedimentation tank 6 are both connected to the inlet of the sludge thickening tank 11.

[0072] The process flow for treating sludge drying and condensation wastewater is as follows:

[0073] The sludge drying condensation wastewater (pollutant content is shown in Table 1) flows by gravity into the regulating tank 1 for homogenization and equalization; a submerged mixer is installed in the regulating tank 1 to prevent sludge sedimentation; the sludge drying condensation wastewater (≥55°C) in the regulating tank 1 is pumped to the plate heat exchanger 2 for heat exchange, and the water temperature of the sludge drying condensation wastewater after treatment by the heat exchanger 2 is ≤36°C; after cooling, the wastewater is flotated in the flotation machine 3 by adding drugs (PAC and PAM) to remove suspended solids in the wastewater; the flotation effluent flows by gravity into the hydrolysis acidification tank 4, and the organic matter in the wastewater is hydrolyzed in the hydrolysis acidification tank 4 to improve the biodegradability of the wastewater. A submerged mixer is installed in the hydrolysis acidification tank 4; the hydrolysis acidification effluent passes through the two-stage A / O unit 5 (in turn through the A / O reaction tank 51 and the sedimentation tank 5 2. A / O reaction tank 51 and sedimentation tank 52) are used to remove organic matter, ammonia nitrogen and other pollutants from the wastewater; a submersible mixer is installed in tank A; the two-stage A / O reaction tank 51 is respectively equipped with nitrification liquid reflux denitrification, and alkali and carbon source (sodium acetate) are added to ensure the alkalinity of the wastewater and a reasonable carbon-nitrogen ratio; the effluent from the sedimentation tank 52 downstream of the two-stage A / O unit 5 flows into the flocculation sedimentation tank 6, where suspended matter in the wastewater is removed by precipitation through the addition of drugs (PAC and PAM); the effluent from the flocculation sedimentation tank 6 enters the disinfection tank 8 (with the disinfectant sodium hypochlorite) for disinfection, then enters the drainage tank 9, and then enters the shallow sand filter 10 for filtration after passing through the external discharge pump. The effluent water quality test results are shown in Table 2, and the effluent can be reused in the power plant.

[0074] The suspended matter separated by the flotation machine 3 is discharged into the sludge thickening tank 11; the sludge in the flocculation sedimentation tank 6 is discharged into the sludge thickening tank 11 through the sludge pump; the two sedimentation tanks 52 are both equipped with a power pump, which can serve as a sludge return pump to return part of the sludge in the sedimentation tank 52 to the A tank through the sludge return pump, and can also serve as a sludge discharge pump to discharge the remaining sludge into the sludge thickening tank 11; the sludge in the sludge thickening tank 11 is concentrated and pressurized by the pump and enters the screw stacking machine 12 for dehydration. The dehydrated water enters the ditch and then merges into the regulating tank 1. The dehydrated sludge is sent to the plant sludge drying system for further disposal.

[0075] Comparative Example 1

[0076] The method described in Example 1 is used for implementation, except that no filler for microorganisms to attach is provided inside the aerobic tank 512 .

[0077] After the sludge drying and condensation simulated wastewater in the above Example 1 and Comparative Example 1 was treated by the power plant sludge drying and condensation wastewater treatment and reuse system, the effluent water quality obtained was shown in Table 2 below.

[0078] Table 2

[0079]

[0080] As can be seen from Table 2, the system provided by the utility model can effectively remove suspended solids, COD, BOD, ammonia nitrogen, total phosphorus, etc. in sludge drying and condensation wastewater, so that its effluent can meet the water standards for direct current cooling water in power plants.

[0081] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be considered as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A system for treating and reusing sludge drying and condensation wastewater from a power plant, characterized in that: The system comprises a regulating tank (1), a heat exchanger (2), an air flotation machine (3), a hydrolysis and acidification tank (4), at least one A / O unit (5), and a flocculation and sedimentation tank (6) which are sequentially arranged along the flow direction of the wastewater. Each of the A / O units (5) comprises an A / O reaction tank (51) and a sedimentation tank (52), wherein the A / O reaction tank comprises an anoxic tank (511) and an aerobic tank (512), wherein the anoxic tank (511), the aerobic tank (512) and the sedimentation tank (52) are sequentially arranged along the flow direction of the wastewater, and wherein a filler for microorganisms to attach is provided inside the aerobic tank (512).

2. The system according to claim 1, wherein: The aerobic pool (512) is provided with power plant slag filler (5121) and soft filler (5122) inside.

3. The system according to claim 1, wherein: The system further comprises a blower (7), a cyclone aerator (5124) is provided in the aerobic tank (512), and the blower (7) is connected to the cyclone aerator (5124).

4. The system according to claim 1, wherein: A stirrer (5111) is provided in the anoxic tank (511).

5. The system according to claim 1, wherein: The sludge outlet of the sedimentation tank (52) is connected to the A / O reaction tank (51).

6. The system according to claim 1, wherein: The system further comprises a disinfection tank (8), which is connected to the water outlet of the flocculation sedimentation tank (6).

7. The system according to claim 6, characterized in that The system further comprises a shallow sand filter (10), which is connected to the outlet of the disinfection tank (8).

8. The system according to claim 1, wherein: The system further comprises a sludge concentration tank (11), wherein the sludge concentration tank (11) is connected to the air flotation machine (3), the sedimentation tank (52) and the flocculation sedimentation tank (6).

9. The system according to claim 8, characterized in that The system further comprises a snail stacking machine (12), and the snail stacking machine (12) is connected to the sludge outlet of the sludge thickening tank (11).

10. The system according to any one of claims 1 to 9, characterized in that: The number of the A / O units (5) is 2, and the two A / O units (5) are arranged in series.

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