System for treating and recycling high-ammonia-nitrogen sludge drying condensation wastewater of power plant

Abstract

The utility model relates to the technical field of wastewater treatment, and discloses a system for treating and recycling high-ammonia-nitrogen sludge drying condensation wastewater in a power plant, which comprises an adjusting tank, a heat exchanger, an air flotation machine, a hydrolysis acidification tank, an A / O unit, a denitrification biological filter and a flocculation sedimentation tank which are sequentially connected along the flowing direction of the wastewater, the 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 the wastewater, and a 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, and the operation cost can be 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 is particularly suitable for treating high-ammonia-nitrogen sludge drying and condensing wastewater.

Description

Technical Field

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

[0002] After natural or artificial dehydration, sludge typically has a moisture content of 60% to 80%. Currently, 80% of sludge generated by sewage treatment plants is not properly disposed of. The pollution and re-pollution caused by sludge storage have become prominent and have attracted public attention. Due to its high moisture content, it is difficult to meet the requirements of subsequent disposal methods such as composting, landfill, and incineration. Technical measures are usually required to reduce the moisture content, and sludge drying is an effective means of reducing sludge moisture content.

[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] Current methods for drying condensate wastewater require large amounts of carbon source reagents at the front-end biochemical treatment stage. Some processes lack advanced treatment at the back end, resulting in high effluent pollutant concentrations. After treatment, the effluent is discharged back into the municipal pipeline network, failing to meet reuse standards. Alternatively, advanced treatment using membrane or adsorption processes can achieve reuse standards, but this can lead to secondary pollution problems such as concentrated water and saturated adsorbent. Furthermore, conventional pretreatment combined with A / O methods is ineffective in removing ammonia nitrogen from high-ammonia nitrogen drying condensate wastewater, resulting in effluent ammonia nitrogen levels failing to meet standards. 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 high-ammonia nitrogen sludge drying and condensing wastewater from power plants, 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 high-ammonia nitrogen sludge drying and condensation wastewater from a power plant, the system comprising a regulating tank, a heat exchanger, an air flotation machine, a hydrolysis and acidification tank, an A / O unit, a denitrification biological filter and a flocculation sedimentation tank connected in sequence along the flow direction of the wastewater;

[0007] Among them, the 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 number of the A / O units is 2, and the 2 A / O units are arranged in series.

[0009] Preferably, soft fillers and power plant slag fillers are provided inside the aerobic pool.

[0010] Preferably, the system further comprises a blower, and both the aerobic tank and the denitrification biological filter are provided with a cyclone aerator, and the blower is connected to the cyclone aerator.

[0011] Preferably, a stirrer is provided in the anoxic tank.

[0012] Preferably, the system further comprises a sludge thickening tank, and the sludge outlet of the sedimentation tank is communicated with the sludge thickening tank and the anoxic tank respectively.

[0013] Preferably, the system further comprises a snail stacking machine, which is connected to the sludge outlet of the sludge thickening tank.

[0014] Preferably, the system further comprises a disinfection tank, which is connected to the water outlet of the flocculation sedimentation tank.

[0015] Preferably, the system further comprises a shallow sand filter connected to the outlet of the disinfection tank.

[0016] Preferably, the number of the shallow sand filters is 2, and the two shallow sand filters 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 condensing wastewater, and is particularly suitable for the treatment of high-ammonia nitrogen sludge drying and condensing wastewater. The effluent that meets the standards can be used as water for circulating cooling towers in power plants or as water for desulfurization process water.

[0019] (2) The system provided by the utility model has a system in which the structures in operation can be reused, and the equipment operation and maintenance costs are low;

[0020] (3) The system provided by the utility model uses conventional chemicals and equipment in the wastewater treatment process, and the system configuration is simple;

[0021] (4) The system provided by the utility model does not require saturated adsorbent and concentrated water during the wastewater treatment process, resulting in less secondary pollution and resource utilization;

[0022] (5) The system provided by the utility model improves the biodegradability of sludge drying and condensation wastewater by setting up a hydrolysis and acidification tank, reduces the amount of carbon source added in the biochemical section, and reduces operating costs;

[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, so that the process has a large processing capacity, a small amount of sludge generation, and no sludge bulking 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 the one-time investment and operating costs, reduce the floor space, and is easy to manage and resistant to load shocks.

[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 high-ammonia nitrogen sludge drying and condensation wastewater from a power plant 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-denitrification biological filter; 7-flocculation sedimentation tank; 8-blower; 9-sludge thickening tank; 10-snail stacking machine; 11-disinfection tank; 12-shallow sand filter. 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 high-ammonia nitrogen sludge drying and condensation wastewater from power plants. Figure 1 The system includes a regulating tank 1, a heat exchanger 2, an air flotation machine 3, a hydrolysis acidification tank 4, an A / O unit 5, a denitrification biological filter 6 and a flocculation sedimentation tank 7, which are sequentially connected along the flow direction of the wastewater;

[0032] Among them, the A / O unit 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 the design can be based on actual working conditions. For example, the A / O reaction tank 51 can be a single tank body, divided into an anoxic tank 511 and an aerobic tank 512 by a partition or other structure. 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 high-ammonia-nitrogen sludge drying and condensing wastewater from a power plant is specifically high-ammonia-nitrogen sludge drying and condensing wastewater from a thermal power plant.

[0035] 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 + denitrification biological filter 6). 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 embodiment, heat exchanger 2 is a closed heat exchanger 2, where wastewater from regulating tank 1 exchanges heat with the cooling circulating water in the closed heat exchanger 2 to cool the wastewater.

[0036] 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.

[0037] 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.

[0038] In this utility model, the biochemical reaction process is an A / O process + biological contact oxidation + denitrification biological filter 6. 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 air 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).

[0039] The system of 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 1.5-2.5 kg / 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.

[0040] The present invention does not limit the number of A / O units 5, and may be one, two, three, or four. In a preferred embodiment, the number of A / O units 5 is two, and 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, two A / O reaction tanks 51 and two sedimentation tanks 52 are each provided.

[0041] The fiber-type soft filler 5122 used in conventional biological contact oxidation methods has a large theoretical specific surface area, is easy to form biofilm, has a low cost, saves on shipping, is easy to assemble, and is non-clogging. However, it is prone to broken wires and center rope breakage, and has a service life of only 1-2 years. In order to increase the service life of the filler in the aerobic tank 512 and save costs, in a preferred embodiment, each of the aerobic tanks 512 is provided with a soft filler 5122 (fiber-type soft filler 5122) and a power plant slag filler 5121. Power plant slag has a large specific surface area and is porous, which can provide space for biological attachment. In addition, using power plant slag as filler, which is locally sourced, can reduce transportation and storage costs and achieve 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, compensate for the short service life of the soft filler 5122, and on the other hand, achieve resource utilization of the power plant slag, thereby reducing the operating costs of the system.

[0042] 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.

[0043] In the present invention, the system further includes a blower 8. A cyclone aerator 5124 is provided in the aerobic tank 512. The blower 8 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.

[0044] 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 .

[0045] 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.

[0046] In a preferred embodiment, each of the anoxic tanks 511 is provided with a mixer 5111. The mixer 5111 can better allow the sewage to come into contact with the microorganisms, thereby enhancing the treatment effect.

[0047] The utility model can further remove nitrates in sewage by setting up the denitrification biological filter 6, so that it has a good effect on treating high-ammonia nitrogen sludge drying and condensation wastewater. At the same time, the denitrification biological filter 6 has the advantages of small footprint, high treatment efficiency, and low engineering investment cost.

[0048] In the present invention, the system also includes a blower 8. A cyclone aerator 5124 is provided in both the aerobic tank 512 and the denitrification biological filter 6. The blower 8 is connected to the cyclone aerator 5124 to provide the microorganisms in the aerobic tank 512 and the denitrification biological filter 6 in the biochemical section with oxygen required for survival.

[0049] In the present invention, the effluent from the denitrification biological filter 6 in the biochemical section flows by gravity into the flocculation sedimentation tank 7. The flocculation sedimentation tank 7 can be used to remove suspended solids in the wastewater by precipitation. 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, enlarging the particles and 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 7 can meet discharge standards in terms of color and suspended solids content.

[0050] In a specific embodiment, the reagents added to the flocculation sedimentation tank 7 are PAC and PAM. In order to improve the separation effect, preferably, a coagulant aid can also be added.

[0051] In a specific embodiment, the sludge in the flocculation sedimentation tank 7 is discharged into the sludge thickening tank 9 by gravity.

[0052] In a specific embodiment, the system may further include a disinfection tank 11, which is connected to the outlet of the flocculation sedimentation tank 7 and is used to disinfect the effluent from the flocculation sedimentation tank 7, thereby further killing harmful pathogenic microorganisms in the wastewater and preventing the spread of disease. The present invention is not limited to the specific disinfection treatment method, and can be a disinfection treatment method commonly used in the art, such as: chlorination disinfection, 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 11.

[0053] In a specific embodiment, the system further includes a shallow sand filter 12, which is connected to the outlet of the disinfection tank 11 and is used to filter the effluent from the disinfection tank 11. The shallow sand filter 12, also known as a fully automatic shallow sand filter 12, is a finished device with a large flow rate and no maintenance. The utility model uses the shallow sand filter 12 for filtration treatment, which has good effect and low cost.

[0054] In order to achieve better treatment effects, in a preferred embodiment, the number of the shallow sand filters 12 is 2, and the two shallow sand filters 12 are arranged in series. After the effluent from the disinfection pool 11 is treated by the two shallow sand filters 12, the effluent water quality is better and can be reused or discharged in compliance with standards.

[0055] In a preferred embodiment, the system further includes a sludge thickening tank 9, and the sludge outlet of the sedimentation tank 52 is respectively connected to the sludge thickening tank 9 and the anoxic tank 511. Specifically, each sedimentation tank 52 is 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 connected anoxic tank 511 through the sludge return pump, and can also serve as a sludge discharge pump to discharge the remaining sludge into the sludge thickening tank 9.

[0056] In a specific embodiment, the system may further include a screw stacker 10 for dewatering the sludge from the sludge thickening tank 9. 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 treatment.

[0057] In a specific embodiment of the present invention, the process of using the system described in the present invention to treat high-ammonia nitrogen sludge drying condensate wastewater from a power plant includes: the condensate wastewater generated by drying high-ammonia nitrogen sludge flows by gravity into the regulating tank 1 for homogenization and equalization; a submerged mixer 5111 is installed in the regulating tank 1 for stirring to prevent sludge deposition; the water temperature of the dried condensate wastewater is ≥55°C, and the high water temperature affects the growth of microorganisms in the subsequent biochemical stage, and needs to be cooled; the sludge drying condensate wastewater in the regulating tank 1 is pumped to the closed heat exchanger 2 for heat exchange, and the water temperature of the sludge drying condensate 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 matter in the wastewater; the flotation effluent flows by gravity into the hydrolysis and acidification tank 4, and the organic matter in the wastewater is hydrolyzed in the hydrolysis and acidification tank 4 to improve the biodegradability of the wastewater, and a submerged mixer 5111 is installed in the hydrolysis and acidification tank 4; the hydrolysis and acidification effluent passes through a two-stage A / O unit 5 (with The wastewater is sequentially passed through the A / O reaction tank 51, the sedimentation tank 52, the A / O reaction tank 51 and the sedimentation tank 52 to remove organic matter, ammonia nitrogen and other pollutants in the wastewater; wherein, a submerged mixer 5111 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 of the sedimentation tank 52 at the end of the two-stage A / O unit 5 is discharged. The wastewater enters the denitrification biological filter 6 for further ammonia and nitrogen removal, and then enters the flocculation sedimentation tank 7, where suspended solids in the wastewater are removed by adding chemicals for precipitation. The effluent from the flocculation sedimentation tank 7 is disinfected and then discharged or reused. Two shallow sand filters 12 are installed after the effluent pump to ensure that the recycled water meets the SS standard. After meeting the standard, the water can be used as water for the desulfurization process of the power plant or for the circulating cooling tower. The backwash water from the shallow sand filter 12 and the supernatant from the sludge concentration tank 9 can flow into the ditch by gravity and then into the regulating tank 1.

[0058] The flocculated sludge is discharged into the sludge thickening tank 9 through the sludge pump; the two sedimentation tanks 52 are both equipped with a power pump, which can be used as a sludge return pump to return part of the sludge in the sedimentation tank 52 to the A tank of the A / O reaction tank 51 connected to it through the sludge return pump, and can also be used as a sludge discharge pump to discharge the remaining sludge into the sludge thickening tank 9; the sludge in the thickening tank is concentrated and pressurized by the pump and enters the screw stacking machine 10 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.

[0059] Through the above technical scheme, the system provided by the utility model is used to treat high-ammonia nitrogen sludge drying and condensing wastewater from power plants, which has the following advantages: 1. The process flow is short and can effectively remove suspended solids, COD, ammonia nitrogen, total phosphorus, etc. in high-ammonia nitrogen 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 adsorbent 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 combined method of flotation-hydrolysis acidification-two-stage A / O+biological contact oxidation+denitrification biological filter 6-flocculation sedimentation-disinfection-shallow sand filtration-reuse within the power plant; 6. The treated dried condensing wastewater can be reused within the power plant, which saves water resources on the one hand and reduces the amount of wastewater discharged into the municipal pipeline network on the other hand. 7. The biodegradability of sludge drying and condensation wastewater is improved through a hydrolysis and acidification process, reducing the amount of carbon source added in the biochemical stage and lowering operating costs. 8. The A / O process is combined with the biological contact oxidation process, with the biological contact oxidation tank serving as the main operating unit of the aerobic process (stage O). This process has a high processing capacity, generates little sludge, and does not produce sludge bulking during operation, ensuring stable effluent quality. Because this process combines the advantages of both the activated sludge process and the biofilm process, it can reduce one-time investment and operating costs, and reduce floor space. It is easy to manage and resistant to load shocks. 9. Nitrates are further removed from the wastewater through the denitrification biological filter 6, making it suitable for the treatment of high-ammonia nitrogen sludge drying and condensation wastewater. 10. The use of a packing combination process combining soft packing 5122 and power plant slag packing 5121 prolongs the packing's service life and achieves resource utilization of the power plant slag, resulting in low cost and low operating costs for the system.

[0060] 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.

[0061] In the following examples and comparative examples, the high-ammonia nitrogen sludge drying condensate wastewater to be treated is simulated wastewater designed based on the conventional water quality conditions of high-ammonia nitrogen condensate wastewater generated by sludge drying in thermal power plants, and its pollutant content is shown in Table 1 below.

[0062] Table 1

[0063] Serial number Project Name unit Wastewater treatment system inlet 1 pH 6-10 2 Suspended solids SS mg / L 1000 3 <![CDATA[BOD5]]> mg / L 600 4 Chemical oxygen demand (CODcr) mg / L ＜1500 5 <![CDATA[Chloride (Cl - )]]> mg / L 100-200 6 Ammonia nitrogen (as N) mg / L 800 7 Total nitrogen (N) mg / L 900 8 Total phosphorus (P) mg / L 10 9 Petroleum mg / L 50-150

[0064] Example 1

[0065] use Figure 1 The operation of this embodiment is performed in the system for drying and condensing wastewater from a power plant with high ammonia nitrogen content.

[0066] 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 denitrification biological filter 6, a flocculation sedimentation tank 7, a disinfection tank 11, and two shallow sand filters 12, which are connected in sequence along the flow direction of the wastewater.

[0067] Each A / O unit 5 includes an A / O reaction tank 51 and a sedimentation tank 52. The A / O reaction tank 51 (refer to Figure 2 As shown in the figure, the anoxic tank 511 (A tank) and the aerobic tank 512 (O tank) 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 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 the denitrification biological filter 6, and a blower 8 is connected to the cyclone aerator 5124 to provide the microorganisms in the O tank and the denitrification biological filter 6 with oxygen required for survival.

[0068] The process flow for treating high-ammonia nitrogen sludge drying and condensation wastewater is as follows:

[0069] The condensed wastewater generated by the drying of high-ammonia nitrogen sludge (see Table 1) flows by gravity into the regulating tank 1 for homogenization and equalization; a submerged mixer 5111 is installed in the regulating tank 1 for stirring to prevent sludge deposition; the sludge drying condensed wastewater (≥55°C) in the regulating tank 1 is pumped to the closed 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 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 and acidification tank 4, and the organic matter in the wastewater is hydrolyzed in the hydrolysis and acidification tank 4 to improve the biodegradability of the wastewater. The hydrolysis and acidification tank 4 is equipped with a submerged mixer 5111; the hydrolysis and acidification effluent passes through the two-stage A / O unit 5 (i.e., passes through the A / O reaction tank 51, the sedimentation tank 52, the A / O reaction tank 51 and the sedimentation tank 53 in sequence) Pool 52) to remove organic matter, ammonia nitrogen and other pollutants in the wastewater; wherein, a submersible mixer 5111 is set in Pool A; the two-stage A / O reaction pool 51 is respectively provided 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 of the sedimentation pool 52 at the end is further denitrified by the denitrification biological filter 6, and then enters the flocculation sedimentation pool 7, and the suspended matter in the wastewater is removed by precipitation by adding drugs (PAC and PAM); the effluent of the flocculation sedimentation pool 7 enters the disinfection pool 11 (with the disinfectant sodium hypochlorite) for disinfection, and then enters the two shallow sand filters 12 in series after passing through the external discharge pump for filtration. The water quality test results of the effluent of the shallow sand filter 12 at the end are shown in Table 2. The effluent can be used as water for the desulfurization process water of the power plant or as water for the circulating cooling tower.

[0070] The suspended matter separated by the flotation machine 3 is discharged into the sludge thickening tank 9; the sludge in the flocculation sedimentation tank 7 is discharged into the sludge thickening tank 9 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 the A tank of the A / O reaction tank 51 connected to it through the sludge return pump, and can also serve as a sludge discharge pump to discharge the remaining sludge into the sludge thickening tank 9; the sludge in the sludge thickening tank 9 is concentrated and pressurized by the pump to enter the screw press 10 for dehydration, and 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.

[0071] Comparative Example 1

[0072] The method described in Example 1 was followed, except that no filler for microorganism attachment was provided inside the two aerobic tanks 512 .

[0073] The high ammonia nitrogen sludge drying and condensation simulated wastewater in the above Example 1 and Comparative Example 1 was treated by the power plant high ammonia nitrogen sludge drying and condensation wastewater treatment and reuse system, and the effluent water quality obtained was shown in Table 2 below.

[0074] Table 2

[0075]

[0076]

[0077] As can be seen from Table 2, the system provided by the utility model can effectively remove suspended solids, BOD, COD, ammonia nitrogen, total phosphorus, etc. in high-ammonia nitrogen sludge drying and condensation wastewater, so that its effluent can meet the water standards for replenishing the circulating cooling tower of the power plant or replenishing the desulfurization process water.

[0078] 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 high-ammonia nitrogen sludge drying and condensation wastewater from power plants, characterized in that: The system comprises a regulating tank (1), a heat exchanger (2), an air flotation machine (3), a hydrolysis acidification tank (4), an A / O unit, a denitrification biological filter (6) and a flocculation sedimentation tank (7) which are sequentially connected along the flow direction of the wastewater; The A / O unit comprises an A / O reaction tank (51) and a sedimentation tank (52), the A / O reaction tank (51) comprises 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 a filler for microorganisms to attach is provided inside the aerobic tank (512).

2. The system according to claim 1, wherein: The number of the A / O units is 2, and the 2 A / O units are arranged in series.

3. The system according to claim 1 or 2, characterized in that The aerobic pool (512) is provided with soft fillers (5122) and power plant slag fillers (5121).

4. The system according to claim 1 or 2, characterized in that The system further comprises a blower (8), and a cyclone aerator (5124) is provided in both the aerobic tank (512) and the denitrification biological filter (6), and the blower (8) is connected to the cyclone aerator (5124).

5. The system according to claim 1 or 2, characterized in that A stirrer is provided in the anoxic tank (511).

6. The system according to claim 1 or 2, characterized in that The system further comprises a sludge concentration tank (9), and the sludge outlet of the sedimentation tank (52) is respectively connected to the sludge concentration tank (9) and the anoxic tank (511).

7. The system according to claim 6, characterized in that The system further comprises a snail stacking machine (10), and the snail stacking machine (10) is connected to the sludge outlet of the sludge thickening tank (9).

8. The system according to claim 1, wherein: The system further comprises a disinfection tank (11), which is connected to the water outlet of the flocculation sedimentation tank (7).

9. The system according to claim 8, characterized in that The system further comprises a shallow sand filter (12), wherein the shallow sand filter (12) is connected to the outlet of the disinfection tank (11).

10. The system according to claim 9, characterized in that The number of the shallow sand filters (12) is 2, and the two shallow sand filters (12) are arranged in series.

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