Sewage treatment system in alpine region and operation method

Abstract

The invention relates to the technical field of energy conservation and environmental protection, and particularly discloses a sewage treatment system for an alpine region and an operation method. Comprising a pretreatment unit, a biological treatment unit and a tail end treatment unit which are sequentially communicated and arranged in a heat preservation area, the pretreatment unit comprises three sections of grating tanks and three sections of grit chambers, and is used for intercepting solid impurities and inorganic particles in sewage step by step; the biological treatment unit consists of a three-section anaerobic tank, a three-section anoxic tank and a three-section aerobic tank, and degradation of organic matters is realized through segmented treatment of the three-section anaerobic tank, the three-section anoxic tank and the three-section aerobic tank; the tail end treatment unit comprises a three-section sedimentation tank, a three-section filter tank and a disinfection tank and is used for solid-liquid separation, filtration and disinfection; a heat preservation structure is further arranged at the top of the heat preservation area and at least comprises an overburden layer and a heat preservation layer; the heat preservation structure does not need an external heat source, energy consumption can be reduced, and operation cost is saved.

Description

Technical Field

[0001] The present invention relates to the technical field of energy conservation and environmental protection, and in particular to a sewage treatment system and an operation method in high-cold areas. Background Art

[0002] In my country, the high-cold areas located in the upper reaches of the Yangtze River and the Yellow River usually constitute important ecological barrier areas. The ecological environment in these areas is relatively fragile, and the demand for ecological protection is particularly high. The climate characteristics of these areas are characterized by a large temperature difference between day and night, extremely low temperatures in winter, and often deep permafrost. Due to the continued low temperature, the water temperature of the sewage is also relatively low, which directly affects the effect of the biochemical treatment process and makes sewage treatment extremely difficult. In high-cold areas, low temperatures are a perennial state. For example, in Litang County, Sichuan Province, the temperature in winter often remains at around -20°C. On February 17, 2024, the area even reached historical extreme low temperatures, with the temperature plummeting to -37°C. However, for the biological treatment unit of sewage treatment, the average temperature should be controlled between 10 and 20°C to ensure the normal activity of water treatment microorganisms. When the water temperature is below 5°C, the reaction activity of these microorganisms will be greatly inhibited, and their biological activation efficiency will be reduced by more than 70% compared with the appropriate temperature, which directly leads to the difficulty of sewage treatment indicators to meet the expected standards. In actual applications, although measures have been taken to install integrated sewage treatment equipment directly on the construction site, these equipment are usually suitable for smaller sewage treatment plants. Even so, the treatment effect is still unsatisfactory due to the problem of low water temperature.

[0003] The patent "An Energy-Saving Sewage Treatment Device for Alpine Regions" (authorization announcement number CN117401824B, hereinafter referred to as prior art 1) discloses a sewage treatment device for alpine regions. In the current technical field, a windmill device driven by wind, in conjunction with the use of vertical air distribution pipes and horizontal air distribution pipes, has realized the reoxygenation process in the sewage pool. This technical means enables the degradation tank to perform alternating aerobic and anaerobic operations, thereby effectively removing harmful pollutants such as chemical oxygen demand (COD) and ammonia nitrogen in the sewage. In addition, by carefully designing the transmission ratio of the two transmission components, it can be ensured that the rotation speed of the stirring device in the anaerobic tank is lower than the rotation speed of the stirring device in the facultative tank. Such a design not only improves the efficiency of sewage treatment, but also enhances the reliability of the entire treatment process.

[0004] However, it should be noted that this type of sewage treatment equipment is usually suitable for smaller sewage treatment plants. They may encounter poor treatment effects when treating sewage, especially when the water temperature is low. This is mainly because the low temperature environment slows down the metabolic activity of microorganisms, thus affecting the efficiency and quality of sewage treatment. Summary of the invention

[0005] In view of this, an embodiment of the present invention provides a sewage treatment system and operation method for high-altitude cold areas, which is used to solve the problem that the activity of microorganisms in the sewage treatment system will be significantly reduced in high-altitude cold areas or when the temperature is extremely low in winter, especially when the temperature is below 5°C, the reaction activity of the microorganisms will be greatly inhibited, resulting in a significant decrease in sewage treatment efficiency.

[0006] In the first aspect, an embodiment of the present invention provides a sewage treatment equipment for high-altitude cold areas, including a pretreatment unit, a biological treatment unit and a terminal treatment unit which are connected in sequence and arranged in an insulation zone; the pretreatment unit includes a three-stage grid tank and a three-stage grit tank, which are used to intercept solid impurities and inorganic particles in the sewage step by step; the biological treatment unit is composed of three-stage anaerobic tanks, three-stage anoxic tanks and three-stage aerobic tanks, and organic matter degradation is achieved through staged treatment of three-stage anaerobic tanks, three-stage anoxic tanks and three-stage aerobic tanks; the terminal treatment unit includes three-stage sedimentation tanks, three-stage filtration tanks and a disinfection tank, which are used for solid-liquid separation and filtration and disinfection; an insulation structure is also provided on the top of the insulation zone, and the insulation structure at least includes a covering soil layer and an insulation layer.

[0007] Preferably, the grid spacing of the three-stage grid pool decreases step by step, and the spacing of the first-stage grid pool is 30-50 mm, the spacing of the second-stage grid pool is 10-20 mm, and the spacing of the third-stage grid pool is 5-10 mm; the three-stage grit chambers respectively adopt a combination of a horizontal flow grit chamber, an aerated grit chamber and a cyclone grit chamber, and achieve sand separation through hydraulic control.

[0008] Preferably, a sludge return channel is provided between the three-stage anaerobic tank and the three-stage anoxic tank, and a mixed liquid return system is provided at the bottom of the three-stage aerobic tank to return the nitrified liquid to the anoxic tank; the aeration intensity of the three-stage aerobic tank decreases step by step, and the aeration volume of the first-stage aerobic tank is 3-5m 3 / h, the aeration volume of the second aerobic pool is 2-3m 3 / h, the aeration volume of the third aerobic pool is 1~2m 3 / h.

[0009] Preferably, the disinfection pool is equipped with an ultraviolet disinfection device and an online water quality monitoring system for real-time monitoring of COD, ammonia nitrogen, total phosphorus and fecal coliform indicators, so that the water is discharged after reaching the standards;

[0010] The three-stage filtration unit consists of a sand filter, a fiber ball filter and an activated carbon filter, and the filtration accuracy is gradually improved to 0.5 to 1 micron.

[0011] Preferably, the three-stage grid tank, three-stage grit tank, three-stage anaerobic tank, three-stage anoxic tank, three-stage aerobic tank, three-stage sedimentation tank, three-stage filtration tank and disinfection tank are arranged in sequence with gradually decreasing heights, and an equipment layout area is provided.

[0012] Preferably, the insulation layer is composed of a composite of 20-30mm sprayed rigid polyurethane foam and 35-45mm lightweight aggregate insulation concrete, and the covering thickness is at least greater than 2.0m; wherein, a composite insulation block layer is also provided on the outer side of the insulation zone, the layer thickness of the composite insulation block is greater than or equal to 240mm, and a 20-30mm rigid polyurethane foam board is filled in the middle.

[0013] Preferably, it also includes a plurality of wastewater pipes; the wastewater pipes in the equipment layout area are designed with gravity flow, and the slope is greater than or equal to 0.5%; the power equipment in the equipment layout area is centrally arranged.

[0014] Secondly, a sewage treatment method for high-altitude cold areas is provided, including: calculating the thickness of the insulation layer and the thickness of the covering layer according to the local air temperature, sewage water temperature and operation requirements; arranging the pretreatment unit, the biological treatment unit and the terminal treatment unit in sequence in the insulation area, and insulating the pretreatment unit, the biological treatment unit and the terminal treatment unit through the insulation layer and the covering layer; gradually passing the wastewater through the pretreatment unit, the biological treatment unit and the terminal treatment unit for treatment, and discharging it after meeting the standards.

[0015] Preferably, the thermal conductivity of the thermal insulation structure is less than 0.05 W / m 2 K, and the covering soil thickness is greater than or equal to the maximum frozen soil thickness.

[0016] Preferably, it is characterized in that the wastewater is gradually passed through the pretreatment unit, the biological treatment unit and the terminal treatment unit for treatment, and the discharge after meeting the standards includes: the wastewater enters from the wastewater pipe on the left, passes through three-stage grid tanks and three-stage grit tanks in sequence to complete preliminary pretreatment; then flows into three-stage anaerobic tanks, three-stage anoxic tanks and three-stage aerobic tanks for biological treatment; then passes through three-stage sedimentation units and three-stage filtration units for terminal treatment; finally enters the disinfection tank for disinfection and is discharged after meeting the standards.

[0017] The sewage treatment system and operation method for high-cold areas provided by the present invention have the following beneficial effects:

[0018] The insulation structure provided by the present invention effectively reduces the heat loss during the sewage treatment process by providing a covering soil and insulation layer above the wastewater treatment pool and equipment, thereby ensuring that the system can maintain a stable treatment temperature in extremely cold climates. The selection of insulation layer materials and the design of thickness can ensure that the sewage treatment system maintains a suitable temperature in a low temperature environment, avoiding a significant decrease in microbial activity in the biological treatment unit due to low temperature, thereby improving sewage treatment efficiency. Especially in high-cold areas, this insulation structure does not require an external heat source, can reduce energy consumption and save operating costs, while preventing sewage pipes and treatment structures from being damaged or performance degradation due to freezing, thereby extending the service life of the system and reducing maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solution of the embodiment of the present invention, the following is a brief introduction to the drawings required for use in the embodiment of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work, and these are all within the protection scope of the present invention.

[0020] Figure 1 It is a structural diagram of a sewage treatment system in a high-cold area;

[0021] Figure 2 This is a plan view of the sewage treatment system in a high-cold area;

[0022] Figure 3 It is a schematic diagram of the cross-sectional structure of a sewage treatment system in a high-cold area;

[0023] Parts and numbers in the picture:

[0024] 1-wastewater pipe, 2-grating tank, 3-sand settling tank, 4-anaerobic tank, 5-anoxic tank, 6-aerobic tank, 7-sedimentation tank, 8-filtration tank, 9-disinfection tank, 10-manhole, 11-equipment layout area, 12-wastewater treatment equipment, 13-insulation layer, 14-side insulation structure layer, 15-covering soil. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the embodiment of the present invention clearer, the technical solution in the embodiment of the present invention will be clearly and completely described in conjunction with the drawings in the embodiment of the present invention. It should be noted that, in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. In the description of the present invention, it should be understood that the orientation or position relationship indicated by the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. is based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention. Moreover, the term "includes", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such a process, method, article or device. In the absence of further restrictions, the elements defined by the phrase "comprising..." do not exclude the existence of other identical elements in the process, method, article or device comprising the elements. If there is no conflict, the embodiments of the present invention and the various features in the embodiments can be combined with each other, all within the protection scope of the present invention.

[0026] Example 1

[0027] See also Figure 1 and Figure 2 The embodiment of the present invention provides a sewage treatment device for high-cold areas to ensure that the sewage treatment system can operate stably and efficiently in a low-temperature environment and can operate without the intervention of external heat.

[0028] In the present invention, the proposed sewage treatment equipment 12 is a comprehensive system, which includes a series of treatment units that are connected in sequence and arranged in the insulation area. These treatment units include pretreatment units, biological treatment units and terminal treatment units in sequence. First, the pretreatment unit removes those solid substances and impurities with larger volume and heavier weight in the sewage. Through this stage of treatment, the sewage is preliminarily purified, providing a cleaner water source for the subsequent biological treatment unit. Such a design effectively prevents the blockage or damage problems that may occur in the subsequent equipment and process flow, and ensures the smooth operation of the entire system. Next, the biological treatment unit uses the natural action of microorganisms to effectively degrade and transform the organic matter in the sewage. In this process, harmful pollutants such as ammonia and phosphorus in the sewage are removed, thereby significantly reducing the pollution load of the sewage and achieving water purification. Finally, the terminal treatment unit is responsible for further solid-liquid separation, filtration and disinfection of the biologically treated sewage. Through this series of treatments, it is ensured that the final discharged water quality fully meets the environmental protection standards, and effectively prevents the potential harm of pollutants to the environment.

[0029] The coordinated work of these three treatment units ensures that the entire sewage treatment process is completed from the initial physical removal to biological degradation and then to the final water purification. This system design not only ensures the high efficiency of the treatment process, but also ensures that the treated water quality can meet the standard discharge requirements. In addition, these treatment equipment are cleverly set within the insulation area. This design can ensure that the temperature of the sewage is effectively maintained during the wastewater treatment process, which is very important for the activity of microorganisms and the efficiency of the entire treatment process.

[0030] See also Figure 1 The pretreatment unit includes three-stage grid tank 2 and three-stage grit tank 3, which are used to intercept solid impurities and inorganic particles in sewage step by step; the biological treatment unit consists of three-stage anaerobic tank 4, three-stage anoxic tank 5 and three-stage aerobic tank 6, and organic matter degradation is achieved through segmented treatment of three-stage anaerobic tank 4, three-stage anoxic tank 5 and three-stage aerobic tank 6; the terminal treatment unit includes three-stage sedimentation tank 7, three-stage filtration tank 8 and disinfection tank 9, which are used for solid-liquid separation and filtration disinfection.

[0031] The three-stage grid pool 2, three-stage grit pool 3, three-stage anaerobic pool 4, three-stage anoxic pool 5, three-stage aerobic pool 6, three-stage sedimentation pool 7, three-stage filtration pool 8 and disinfection pool 9 are arranged in a circular shape in sequence, and a certain space is left in the middle after the arrangement is completed. Moreover, compared with other treatment pool arrangements (such as longitudinally arranged treatment pools), these treatment pools arranged in a circular shape require a lower depth from the ground downward, mainly because they require horizontal construction, which makes the construction difficulty lower and is more convenient for the arrangement of such treatment pools.

[0032] See also Figure 1 The grid pool 2 is usually composed of a coarse grid and a fine grid, which is a set of parallel metal or plastic grid bars installed at the front end of the sewage treatment facility. It can have different spacings to intercept solid debris of different sizes. Generally, a mechanical or manual cleaning device is provided to regularly remove the intercepted debris. The grid size of the three-stage grid decreases step by step. The grid can be mechanically lifted and cleaned regularly, and reset after cleaning.

[0033] The principle of the grid pool 2 is mainly the physical interception principle. After the sewage enters the grid pool 2, the water flows through the gaps between the grid bars, while larger floating objects, such as branches, plastic bags, rags, large particles of solid garbage, etc., will be blocked by the grid bars. If these solid debris are not removed, they may damage subsequent processing equipment, such as water pumps, pipes, etc., affecting the normal operation of the entire treatment system. The coarse grid can intercept larger solids, while the fine grid further intercepts smaller suspended solids to ensure the smooth operation of the subsequent treatment units.

[0034] See also Figure 1 , the grit chamber 3 has many types, the common ones are horizontal grit chamber 3, aerated grit chamber 3 and cyclone grit chamber 3. Generally, it has a certain length, width and depth, and has a water inlet, a water outlet and a grit bucket. The horizontal grit chamber 3 is a rectangular tank body, and the water flows in the horizontal direction; the bottom of the aerated grit chamber 3 is provided with an aeration device to make the water flow produce a rotating flow state; the cyclone grit chamber 3 uses the principle of hydraulic cyclone to form a cyclone through the special design of the inlet and outlet. The three-stage grit chamber 3 can select the same or different types of grit chambers 3 for sand treatment according to the specific water quality conditions. Generally, a combination of horizontal grit chamber, aerated grit chamber, horizontal grit chamber or a combination of horizontal grit chamber, cyclone grit chamber and horizontal grit chamber is adopted.

[0035] The grit chamber 3 utilizes the principle of physical precipitation to make the sand and other inorganic particles with a large specific gravity in the sewage settle to the bottom of the tank under the action of gravity or centrifugal force. For the horizontal flow grit chamber, since the water flow velocity is kept within a certain range during design, the sand with a large specific gravity settles quickly under the action of gravity, while the organic matter and other substances with a light specific gravity flow out with the water flow. The aerated grit chamber 3 separates the sand and organic matter through the rising airflow generated by aeration, because the heavier sand will sink to the bottom, while the organic matter will flow out suspended in the water under the combined action of the water flow and airflow. The cyclone grit chamber uses hydraulic cyclone to make the sand sink into the sand hopper at the center of the bottom under the action of centrifugal force, thereby separating the sand and organic matter. Removing the sand in the sewage can prevent the wear and blockage of subsequent treatment equipment and pipelines.

[0036] The anaerobic tank 4 is a sealed or semi-sealed tank body, which provides an oxygen-free environment for microorganisms. A stirring device can be set in the tank to ensure sufficient mixing of sewage and microorganisms. Different partitions can be set as needed to promote anaerobic reactions at different stages. The three-stage anaerobic tank 4 has the same structural type, and a fully enclosed tank body is recommended.

[0037] The anaerobic tank 4 is a place where anaerobic microorganisms decompose complex organic matter in sewage into simple organic matter and some intermediate products under anaerobic conditions. It mainly includes three stages: hydrolysis, fermentation and methanogenesis. The hydrolysis stage is to decompose macromolecular organic matter (such as proteins, polysaccharides, etc.) into small molecular organic matter (such as amino acids, monosaccharides, etc.); the fermentation stage converts small molecular organic matter into fatty acids, alcohols, etc.; the methanogenesis stage further converts these products into gases such as methane and carbon dioxide. Anaerobic treatment can reduce the organic content of sewage and produce biogas to achieve energy recovery. The recovered biogas can be used for canteen cooking and heating of duty personnel rooms according to usage requirements.

[0038] The anoxic tank 5 is generally a tank body structure, which requires a stirring device to ensure uniform mixing of sewage and microorganisms, and an internal reflux system can be set to return the mixed liquid of the aerobic tank 6 to the anoxic tank 5. The three-stage anoxic tank 5 has the same structural type and generally adopts a fully enclosed tank body.

[0039] The anoxic tank 5 mainly utilizes denitrifying bacteria to reduce nitrate and nitrite in the refluxed nitrification solution to nitrogen gas under the condition of anoxic (no molecular oxygen but the presence of combined oxygen such as nitrate and nitrite), thereby achieving the purpose of denitrification. The anoxic tank 5 receives the mixed solution containing nitrate and nitrite from the aerobic tank 6, and at the same time utilizes the organic carbon source in the sewage as an electron donor, and under the action of denitrifying bacteria, performs a denitrification reaction to achieve the removal of nitrogen in the sewage.

[0040] The aerobic tank 6 usually has various forms, such as an aeration tank for the activated sludge method, a biological contact oxidation tank, etc. The aeration tank will be equipped with an aeration device, such as a microporous aeration head, a jet aerator, etc., to provide sufficient oxygen for the microorganisms; the biological contact oxidation tank is provided with fillers, and the microorganisms grow on the fillers. The aerobic tank 6 generally has a return sludge system to return a part of the activated sludge after precipitation in the third stage aerobic tank 6 to the first stage aerobic tank 6. The three-stage aerobic tank 6 has the same structural form, and the aeration volume of the three-stage aerobic tank 6 gradually decreases, and the aeration intensity gradually decreases.

[0041] The aerobic tank 6 utilizes aerobic microorganisms to oxidize and decompose organic matter in sewage under aerobic conditions, converting it into carbon dioxide and water. For the activated sludge method, the aeration device provides oxygen, allowing aerobic microorganisms (such as bacteria, protozoa, metazoa, etc.) to metabolize and grow organic matter under aerobic conditions, and at the same time, nitrifying bacteria convert ammonia nitrogen into nitrate and nitrite, preparing for subsequent denitrification; for the biological contact oxidation method, microorganisms attach to the filler to form a biofilm, and treat organic matter and ammonia nitrogen in sewage under sufficient oxygen.

[0042] The sedimentation unit includes a square tank body with a water inlet area, a sedimentation area, a sludge hopper and a water outlet area. The sedimentation area is the core part, and the suspended matter is precipitated by gravity. An inclined tube or inclined plate sedimentation device can be used to improve the sedimentation efficiency. The sedimentation units are generally consistent in form, and each level of the sedimentation unit can be provided with a bypass pipe. A part of the precipitated sludge can be returned to the 4 ends of the anaerobic tank to maintain biological activity, and the other part can be sent to the filter press for filtration treatment under the action of the sludge discharge pump.

[0043] The sedimentation unit uses the principle of gravity sedimentation to precipitate the suspended solids in the sewage in the sedimentation tank 7. The sewage after biological treatment enters the sedimentation unit. Due to the slowdown of water flow, microbial flocs (such as activated sludge or biofilm fragments) are precipitated to the sludge hopper at the bottom of the tank under the action of gravity to form sludge, realize solid-liquid separation, and greatly reduce the suspended solid content of the sewage.

[0044] The filtration unit is usually in the form of a sand filter, a fiber ball filter or an activated carbon filter. The sand filter is composed of sand layers of different particle sizes; the fiber ball filter is filled with fiber balls; and the activated carbon filter is filled with activated carbon particles or fibers. It has a water inlet, a filter material layer, a support layer and a water outlet. Some are also equipped with a backwashing device to ensure the long-term stable operation of the filter. Usually, the three-stage filtration single option will be configured with a sand filter + a fiber ball filter + an activated carbon filter; and the overall filtration accuracy is set in a step-by-step manner.

[0045] The filter unit type is filtered by the physical filtering principle. When the sewage passes through the filter material layer, fine suspended matter, colloid and other impurities are intercepted by the filter material, further removing the residual solid particles and some organic matter, improving the clarity and water quality of the sewage. The sand filter relies on the filtering effect of sand particles; the fiber ball filter relies on the adsorption and interception of fiber balls; in addition to physical filtration, the activated carbon filter also uses the adsorption effect of activated carbon to adsorb some dissolved organic matter and odor substances, so as to further improve the water quality.

[0046] The disinfection pool 9 can be a rectangular pool body, equipped with a dosing device or disinfection equipment. Common disinfection methods include ultraviolet disinfection, chlorine dioxide disinfection, liquid chlorine disinfection, etc. For dosing disinfection, a dosing point and a stirring device will be set to ensure that the disinfectant is evenly mixed; for ultraviolet disinfection, an ultraviolet lamp will be installed. Considering the comprehensive cost and convenience factors, the ultraviolet disinfection pool 9 is often selected.

[0047] The ultraviolet disinfection uses the bactericidal effect of ultraviolet rays to destroy the DNA structure of microorganisms and make them inactive; chlorine dioxide and liquid chlorine disinfection use the strong oxidizing properties of disinfectants to oxidize the cell structure and enzyme system of microorganisms, kill microorganisms, and achieve the purpose of disinfection, ensuring that the effluent meets the discharge standards and preventing pathogenic microorganisms in sewage from causing harm to the environment and human health.

[0048] In the embodiment of the present invention, the three-stage grid pool 2, the three-stage grit chamber 3, the three-stage anaerobic tank 4, the three-stage anoxic tank 5, the three-stage aerobic tank 6, the three-stage sedimentation tank 7, the three-stage filtration tank 8 and the disinfection tank 9 are closely arranged together through a circular surround layout to form a connected overall treatment structure. Such a layout can effectively concentrate the heat inside the tank body and avoid heat loss. Especially in cold environments, this layout helps to keep the temperature difference between the units small, ensuring that the entire system can maintain a stable operating temperature at low temperatures. In addition, the circular surround design makes the flow path of the wastewater more concentrated and closed during treatment, and the flow direction of the water flow can help circulate and distribute the heat in the system. Especially in the biological treatment unit in the system, the heat exchange between the tank bodies and the internal circulation of the water flow help to improve the temperature stability. In this way, the heat between the treatment tanks will not leak out quickly, which helps to maintain the higher temperature required for microbial growth and ensure the efficiency of biological treatment.

[0049] The circular layout also allows the compact layout of the tank bodies, and the external insulation layer 13 and the covering soil 15 can form a common insulation barrier to reduce the impact of external cold air on the system. The circular layout allows the treatment tanks to be closer together, sharing the benefits of the covering soil 15 and the insulation layer 13, thereby reducing temperature fluctuations caused by the cold climate outside. This structure improves the system's ability to adapt to low temperatures, ensuring that even in extremely cold weather, the sewage temperature in the system can still be maintained within an appropriate range.

[0050] The circular wraparound design also minimizes the temperature difference between the pools, avoiding the problem of excessive temperature differences that may exist in traditional layouts (for example, the temperature of the pool far away from the heat source may be lower; wastewater causes heat loss through flow). Through the wraparound layout, each treatment pool is in a relatively uniform thermal environment, which helps to maintain the stability of the treatment process, especially in cold regions, to avoid the impact of low temperatures on microbial activity or treatment efficiency in some pools.

[0051] The circular surround pool layout not only reduces heat loss, but also helps reduce the need for additional heating. Due to the close layout and shared insulation effect between the pools, the demand for external heat sources is greatly reduced, saving energy consumption. This design not only saves energy in high-cold areas, but also avoids additional investment and maintenance costs for external heating equipment, reducing the operating costs of the entire sewage treatment system. Overall, the circular surround layout helps to improve the thermal effect of the system, reduce the interference of external cold air on the system, ensure that the sewage treatment system in high-cold areas can still operate stably in winter, and has excellent insulation effect and economic benefits.

[0052] The reasonable setting of the equipment layout area 11 facilitates the centralized management and maintenance of power equipment, backwashing system and dosing system, etc., and improves the operation efficiency. The wastewater pipe 1 is designed to rely on gravity flow to enter the wastewater treatment pool and equipment, which reduces the dependence on additional power equipment, reduces the operation cost, and also reduces the risk of pipeline rupture due to excessive pressure. Especially in the low temperature environment of high-altitude cold areas, the protection of the pipeline is more important. The three-stage unit treatment and the circular surround layout arrange the main biological treatment in the middle of the equipment layout area 11, effectively reducing heat loss. The unit can effectively improve the removal rate of pollution indicators, improve the sewage treatment efficiency, and ensure the central temperature of the biological treatment unit. The temperature of the aerobic pool 6 will be 2 to 3 ° C higher than that of the anaerobic pool 4 and the anoxic pool 5 in the operating state. The treatment process is carried out from the outside to the inside, and the treatment temperature gradually increases. The 15 layers of soil cover have a good insulation effect, and the natural heat dissipation of the power equipment in the central area also helps to increase the temperature of the water pool in the back-end water treatment link.

[0053] Furthermore, when these treatment pools are arranged in a return shape, an equipment layout area 11 and a layout area for related auxiliary facilities are also arranged in the space formed by them. During use, wastewater flows through each treatment unit in turn through the wastewater pipe 1, completes the entire sewage treatment process, and is discharged after meeting the standards. When the equipment requires personnel to enter the system for operation, maintenance and overhaul, the manhole 10 is provided to facilitate the operation. The loss equipment layout area 11 also centrally arranges power equipment, backwashing system and dosing system, etc., for easy management and operation control.

[0054] Preferably, the grid spacing of the three-stage grid pool 2 decreases step by step, and the spacing of the first stage grid pool 2 is 30-50 mm, which mainly intercepts larger floating objects, such as branches, plastic bags, large particles of garbage, etc.

[0055] The spacing of the second section of the grating pool 2 is 10 to 20 mm, which further removes smaller suspended matter and ensures that the particles in the sewage are screened out more finely, providing a cleaner water source for the subsequent grit chamber 3 and biological treatment unit.

[0056] The spacing of the third section grid pool 2 is 5 to 10 mm, which can filter out finer debris thoroughly to ensure that there are almost no particles in the sewage to avoid blockage and wear of subsequent equipment (such as pumps, pipes, reaction tanks, etc.).

[0057] The three-stage grit chamber 3 is a combination of a horizontal grit chamber 3, an aerated grit chamber 3 and a cyclone grit chamber 3, and the sand separation is achieved through hydraulic control. The combination of the three-stage grid tank 2 and different types of grit chambers 3 can meet the sewage treatment needs of various water qualities, especially for sewage with high particulate matter content or large differences in particle size in the water, and has good adaptability and treatment effect. Different types of grit chambers 3 cooperate with each other to ensure that particles of various sizes can be effectively separated, thereby improving the overall operation efficiency of the system.

[0058] This three-stage setup ensures that particulate matter and impurities are fully removed after sewage pretreatment, reducing the burden on subsequent biological treatment and terminal treatment units.

[0059] For example, biological treatment units (such as anaerobic tank 4, anoxic tank 5, aerobic tank 6) are able to work in cleaner water sources, reducing the load of microorganisms and helping to improve their treatment efficiency.

[0060] The terminal treatment units (such as sedimentation tank 7 and filtration tank 8) can also remove suspended solids in the water more efficiently, ensuring that the effluent quality meets the discharge standards.

[0061] Moreover, the combined design of the step-by-step decreasing grid pool 2 and three different types of grit chambers 3 effectively improves the solid removal effect in the sewage pretreatment stage, reduces the burden on the subsequent treatment units, improves the system's treatment efficiency, stability and equipment life, and reduces maintenance costs. This setting can not only handle sewage with high concentrations of solids, but also ensure efficient and stable treatment effects.

[0062] A sludge return channel is provided between the three-stage anaerobic tank 4 and the three-stage anoxic tank 5, and a mixed liquid return system is provided at the bottom of the three-stage aerobic tank 6 to return the nitrified liquid to the anoxic tank 5; specifically, the sludge return channel enables the treated sludge to return to the front end of the anaerobic tank 4, maintain the concentration of microorganisms in the anaerobic tank 4, and improve the processing capacity and efficiency of the anaerobic tank 4. In the anoxic tank 5, the nitrate in the returned sludge can provide a continuous source of ammonia for the denitrification reaction, promote the growth of denitrifying bacteria and the removal of nitrogen, and help improve the deammoniation effect. By reflux of the nitrified liquid, nitrate can be provided to the anoxic tank 5 to maintain the smooth progress of the denitrification reaction in the anoxic tank 5. The nitrate in the refluxed nitrified liquid provides sufficient ammonia source for the denitrifying bacteria, ensuring the efficient deammoniation process. Enhanced reaction stability: Through the reflux of the mixed liquid, the stability of the removal process of pollutants such as phosphorus in the system is maintained, while avoiding the influence of water quality fluctuations on the biological treatment efficiency.

[0063] The aeration intensity of the three-stage aerobic pool 6 decreases step by step. The aeration volume of the first-stage aerobic pool 6 is 3-5m 3 / h, the aeration volume of the second aerobic pool 6 is 2-3m 3 / h, the aeration volume of the third aerobic pool 6 is 1~2m 3 / h.

[0064] In the staged oxidation, the higher aeration volume of the first aerobic pool 6 ensures that the organic matter in the water can be fully degraded by aerobic microorganisms, providing treated water sources for the subsequent pool sections. And as the water quality gradually improves, the aeration volume of the subsequent pool sections gradually decreases, which can avoid excessive oxygen supply and reduce unnecessary energy consumption. At the same time, it can also control the growth of biofilms and ensure the best growth environment for microorganisms at different stages. In practical applications, the lower aeration volume in the third aerobic pool 6 helps to avoid excess oxygen, reduce the pressure on microorganisms, and enhance the activity of denitrifying bacteria, which is helpful for further treatment of sewage, especially in high-ammonia and high-COD sewage, and reduces the operating cost of the system.

[0065] In order to ensure that the discharged water quality meets the sanitary standards, an ultraviolet disinfection device and an online water quality monitoring system are installed in the disinfection pool 9 to monitor the COD, ammonia nitrogen, total phosphorus and fecal coliform group indicators in real time, so that the water can be discharged after reaching the standards; ultraviolet rays are an efficient disinfection method that can effectively kill pathogenic microorganisms (such as bacteria, viruses, etc.) in water. Ultraviolet disinfection does not have chemical additives, will not produce secondary pollution, and can avoid harm to the environment and human health.

[0066] Real-time monitoring of water quality indicators such as COD (chemical oxygen demand), ammonia nitrogen, total phosphorus and fecal coliform bacteria can ensure that the water quality always meets the discharge standards. If the water quality does not meet the standards, the system can remedy it by adjusting the process or adding disinfectants. The introduction of this monitoring system improves the system's adaptability and response speed, making the entire sewage treatment process more accurate and reliable. The online monitoring system can automatically record and report water quality data, reduce manual operations, ensure real-time control and data analysis, and improve the accuracy and efficiency of water quality monitoring.

[0067] The filtration accuracy is gradually improved (to 0.5-1 micron) in the filtration units (sand filter, fiber ball filter and activated carbon filter); as the primary filtration unit, the sand filter can effectively remove larger suspended particles in the water, reduce the burden of subsequent filters, and ensure that the coarser solid impurities in the water are completely removed. The fiber ball filter has a higher filtration accuracy and can remove smaller suspended matter and colloids in the water, further purifying the water quality and achieving higher water quality standards. Activated carbon has good adsorption properties and can remove soluble organic matter, odor substances and some soluble ammonia, phosphorus and other pollutants in the water, ensuring that the water quality achieves better purification effects. In addition, the activated carbon filter can also adsorb trace amounts of harmful substances in the water and effectively remove residual pollutants in the water.

[0068] Through the multi-stage filtration design (sand filter-fiber ball-activated carbon), it can ensure that everything from larger particles to extremely fine colloidal substances can be efficiently removed, the water purification effect is gradually improved, and ultimately ensure that the emission standards are met.

[0069] A covering soil 15 is arranged above the wastewater treatment pool and the equipment, and a top structural insulation layer 13 is arranged between the two. The insulation layer 13 material can be selected from extruded polystyrene foam plastics (extruded board), molded polystyrene foam plastics (ordinary foam board), sprayed rigid polyurethane foam, rigid polyurethane insulation board (product), foam concrete (foam mortar), chemical foamed cement board, lightweight aggregate insulation concrete (ceramsite concrete, etc.), inorganic insulation mortar (vitrified microsphere insulation mortar), polystyrene particle insulation mortar, mineral wool (rock wool), phenolic resin board, expanded perlite insulation mortar inorganic active wall insulation material, etc., or a combination of multiple materials; the thickness of the insulation layer 13 is calculated based on comprehensive factors such as local temperature and sewage water temperature operation requirements, and the thermal conductivity efficiency of the insulation structure is less than 0.05W / m 2 K, the thickness of the covering soil is greater than or equal to the maximum frozen soil thickness.

[0070] This design can effectively utilize the heat preservation performance of the soil, reduce the heat loss of sewage during the treatment process, and enable the treatment system to maintain a relatively stable temperature environment in winter, which is conducive to the growth and metabolism of microorganisms and ensures the sewage treatment effect. At the same time, the covering soil 15 can also protect the treatment structures and equipment from frost heave damage and extend the service life of the system.

[0071] See also Figure 3 For example, the maximum frozen soil depth in Litang County is about 86-120cm. In order to ensure that the soil temperature under the frozen soil is not lower than 10℃, the soil temperature of the project site can be detected in winter. According to local experience, the soil temperature at 2.0m below the frozen soil layer can be controlled at around 4℃. In order to save investment, the top of the structure is designed to be filled with 20-30mm sprayed rigid foam polyurethane or rigid foam polyurethane insulation board, covered with 35-45mm lightweight aggregate insulation concrete (ceramsite concrete, etc.), and covered with 152.0m of soil. A side insulation structure layer 14 is set on the periphery of the structure and equipment layout area 11, and an insulation design is adopted. The insulation layer 13 adopts a composite structure. The structure body can use lightweight aggregate insulation concrete (ceramsite concrete, etc.) under the condition of meeting the design structural strength requirements, and the outer side is filled with composite insulation blocks with a thickness of more than 240mm. If necessary, 20-30mm sprayed rigid foam polyurethane or rigid foam polyurethane insulation board is filled between the insulation block and the body. By adjusting the structure and thickness of the insulation material, the overall heat transfer coefficient is less than 0.05W / m 2 ·K. This setting does not require the supply of additional heat source. 3 / d treatment scale of small and medium-sized sewage treatment plants save about 1,200 kWh of energy consumption per day for electric heating of water pools. For high-altitude cold regions with long winters, which can last up to 6 months, this measure is expected to save about 216,000 kWh of electricity per year, with significant economic benefits. There is basically no related post-operation and maintenance cost, and the cost of updating and maintaining electric heating equipment is avoided.

[0072] The comparison data is as follows:

[0073]

[0074] In the embodiment of the present invention, by using an efficient insulation layer 13 (such as extruded polystyrene foam, rigid polyurethane foam, etc.), the heat loss during the sewage treatment process can be greatly reduced. Especially in cold and high-altitude areas, this insulation design ensures that the internal temperature of the system is maintained within an appropriate range, so that the treatment process can be carried out stably without causing the temperature to drop due to the cold weather outside, thereby ensuring the activity and metabolic efficiency of microorganisms.

[0075] In this embodiment, the combination of the thickness of the insulation layer 13 and the covering soil 15 layer can effectively utilize the natural insulation effect of the soil to maintain the temperature in the system under long-term low temperature environment (up to 6 months in winter), so that the sewage treatment plant can continue to operate efficiently in a low temperature environment.

[0076] Furthermore, the activity of microorganisms will decrease significantly at lower temperatures, affecting the treatment effect of biological treatment units (such as anaerobic tank 4, aerobic tank 6, etc.). The thermal insulation design can ensure that the system maintains a suitable temperature (such as above 10°C), thereby promoting the growth and metabolic activities of microorganisms, ensuring the stability of sewage treatment effects, and improving the efficiency of pollutant removal. The stable temperature environment reduces the negative impact of temperature fluctuations on biological reactions, especially for biological treatment processes such as ammonia and phosphorus removal, which can significantly improve the system's treatment capacity and water quality stability.

[0077] Furthermore, the wastewater pipe 1 of the equipment layout area 11 adopts a gravity flow design, and no additional power source is required; by designing the wastewater pipe 1 to adopt a gravity flow mode, the wastewater can rely on natural gravity to flow, thereby avoiding reliance on additional power equipment such as pumps. This greatly reduces operating energy consumption and reduces electricity consumption, especially in high-cold areas, which can avoid excessive load or damage to pump equipment caused by low temperatures in winter. The use of gravity flow design allows the system to efficiently utilize natural resources, reduce the demand for external electricity, reduce electricity consumption and operating costs, and has a significant energy-saving effect.

[0078] The slope of the wastewater pipe 1 is greater than or equal to 0.5%, which ensures that the flow speed of the wastewater in the pipe is appropriate and avoids stagnation or backflow of water. A reasonable slope can not only ensure the smooth flow of sewage, but also effectively reduce the risk of solid deposition and blockage inside the pipe, ensuring long-term stable operation. This slope design can also ensure that the wastewater continues to flow in the system, avoid the deposition of suspended matter caused by too low water flow speed, and reduce the frequency of later cleaning and maintenance.

[0079] When in use, wastewater enters from the wastewater pipe 1, passes through the three-stage grid pool 2 and the three-stage grit pool 3 in turn to complete preliminary pretreatment, then flows into the three-stage anaerobic pool 4, the three-stage anoxic pool 5 and the three-stage aerobic pool 6 for biological treatment, and then passes through the three-stage sedimentation unit and the three-stage filtration unit for further treatment, and finally enters the disinfection pool 9 for disinfection and discharge after meeting the standards. Manholes 10 are distributed throughout the system to facilitate personnel entry and exit. The equipment layout area 11 is located in a suitable position for placing related equipment. The soil covers the treatment pool and equipment to play a role in insulation and protection. The wastewater pipe 1 relies on gravity to introduce wastewater into the treatment system.

[0080] Example 2

[0081] The embodiment of the present invention provides a procedure for setting up and maintaining a sewage treatment device in a high-cold region;

[0082] Step 1: Site selection

[0083] According to the local terrain and sewage pipe network layout, the site selection of the sewage treatment plant is determined, and the site is leveled according to the design requirements; the sewage treatment pool and equipment are built at a location with a low groundwater level and in line with urban planning, ensuring that the treatment structure adopts a suitable concrete structure to ensure its strength and durability, and at the same time, precise construction is carried out according to the circular layout of the treatment pool, including the construction of three-stage grid pool 2, three-stage sand settling pool 3, anaerobic pool 4, anoxic pool 5, aerobic pool 6, sedimentation unit, filtration unit, disinfection pool 9, etc., as well as the planning and construction of the equipment layout area 11, and the location of the manhole 10 is reserved. In areas where the groundwater level is too high, the sewage pipe network elevation is designed according to the requirements of gravity flow, the design elevation of the sewage treatment plant is lowered, the process units are centrally arranged, and the thickness of the soil pile and cover 15 is reasonably determined.

[0084] Step 2: Install the wastewater pipe

[0085] Ensure that the pipelines are tightly connected, have a reasonable slope, and have no leaks, so that the wastewater can flow smoothly between the treatment units by gravity. At the same time, install power equipment, backwash systems, and dosing systems in the equipment layout area 11, and conduct debugging and trial operation to ensure the normal operation of the equipment.

[0086] Step 3: Test run

[0087] Wastewater enters the three-stage screen tank 2 through the wastewater pipe 1, and the debris intercepted on the screen is cleaned regularly to prevent blockage. The wastewater treated by the screen flows into the three-stage grit tank 3, and the grit is discharged regularly to ensure the normal operation of the grit tank 3.

[0088] The pretreated sewage enters the three-stage anaerobic tank 4, the three-stage anoxic tank 5 and the three-stage aerobic tank 6 in sequence. In the anaerobic tank 4, the appropriate hydraulic retention time and anaerobic environment are controlled to promote the action of anaerobic microorganisms; the appropriate organic matter concentration and anoxic conditions are maintained in the anoxic tank 5 to ensure the smooth progress of the denitrification reaction; the aerobic tank 6 provides sufficient oxygen through aeration equipment to maintain the activity of aerobic microorganisms, and at the same time adjusts the aeration volume and mixed liquor reflux ratio according to the water quality monitoring results to ensure the decomposition of organic matter, nitrification and phosphorus removal.

[0089] The effluent from the three-stage aerobic tank 6 enters the three-stage sedimentation unit. A portion of the precipitated sludge flows back to the front end of the anaerobic tank 4. The return ratio is adjusted according to the actual operation situation. The other portion of the sludge is regularly collected and transported for treatment. The effluent from the sedimentation unit enters the three-stage filtration unit, and the filtration equipment is backwashed regularly to ensure the filtration effect.

[0090] The filtered sewage enters the disinfection pool 9, and the online indicator detection system in the disinfection pool 9 monitors the water quality in real time, such as COD, ammonia nitrogen, total phosphorus, fecal coliform group and other indicators. When the water quality meets the standard, the external discharge valve is opened for discharge; if it does not meet the standard, corresponding measures are taken for treatment, such as adjusting process parameters, increasing the amount of disinfectant, etc. The ultraviolet irradiation equipment in the disinfection pool 9 is regularly maintained to ensure its normal operation and effectively kill pathogenic microorganisms.

[0091] Step 4: Maintenance and management stage

[0092] Regularly check the operating conditions of the structures and equipment in the treatment system, including whether the wastewater pipe 1 is leaking, whether the treatment pool has cracks, whether the equipment is operating normally, etc. Enter the system through the manhole 10 to conduct inspection, repair and maintenance work, such as cleaning the sediment at the bottom of the pool and replacing damaged equipment parts.

[0093] Monitor the growth of microorganisms in the biological treatment unit, and adjust the operating parameters such as nutrient addition and aeration volume according to the changes in microbial activity and water quality to ensure the stability of the biological treatment effect. At the same time, regularly check the cover soil 15, and repair it in time if there is settlement or damage to ensure its insulation and protection function.

[0094] Carry out maintenance on the power equipment, backwash system and dosing system in equipment layout area 11 according to the prescribed period, such as replacing lubricating oil, cleaning filters, calibrating dosing equipment, etc., to ensure long-term stable operation of the equipment, extend the service life of the equipment and reduce operating costs.

[0095] Through the above specific implementation methods of construction, operation and maintenance management, the small and medium-sized sewage treatment plant system in high-cold areas of the present invention can operate efficiently and stably in a low-temperature environment, achieve standard treatment of sewage, and have good environmental and social benefits.

[0096] Example 3

[0097] See also Figure 1 The embodiment of the present invention provides a method for treating sewage in a high-cold area, comprising:

[0098] According to the local temperature, sewage temperature and operation requirements, the thickness of the insulation layer 13 and the thickness of the covering soil 15 are calculated; the thickness and material selection of the insulation layer 13 directly affect the energy efficiency and microbial activity of the system. In high-altitude cold areas, it is recommended to choose low thermal conductivity materials, such as extruded polystyrene foam, rigid polyurethane foam and other materials, whose thermal conductivity efficiency is less than 0.05W / m 2 ·K, to reduce heat loss. In addition, according to the changes in local air temperature and sewage water temperature, the thickness of the insulation layer 13 is regularly tested and adjusted to ensure that the system maintains a good insulation effect in cold seasons.

[0099] The thickness of the 15-layer covering soil should be greater than or equal to the maximum frozen soil thickness (e.g. the maximum frozen soil thickness in Litang County is 86-120 cm). The 15-layer covering soil not only provides additional insulation, but also prevents frost heave from damaging the equipment, ensuring that the system can operate stably under extremely cold conditions.

[0100] Through the insulation design, no additional electric heating system is needed to maintain the temperature of the treatment pool. Combined with the insulation layer 13 and the soil cover 15 structure, it is expected that a large amount of energy consumption can be saved, especially in high-altitude cold areas with a winter of up to 6 months. This greatly reduces the operating cost of the electric heating equipment and reduces the maintenance requirements of the equipment.

[0101] The pretreatment unit, the biological treatment unit and the terminal treatment unit are sequentially arranged in the heat preservation zone, and the pretreatment unit, the biological treatment unit and the terminal treatment unit are heat-insulated by the heat preservation layer 13 and the covering soil layer 15;

[0102] The wastewater is gradually passed through the pretreatment unit, biological treatment unit and terminal treatment unit for treatment and discharged after meeting the standards.

[0103] Furthermore, the heat conduction efficiency of the thermal insulation structure is less than 0.05 W / m 2 K, and the thickness of the covering soil 15 is greater than or equal to the maximum frozen soil thickness.

[0104] Furthermore, the wastewater is gradually passed through the pretreatment unit, the biological treatment unit and the terminal treatment unit for treatment, and is discharged after meeting the standards. The wastewater enters from the wastewater pipe 1 on the left, passes through the three-stage grid tank 2 and the three-stage grit tank 3 in sequence to complete preliminary pretreatment; then flows into the three-stage anaerobic tank 4, the three-stage anoxic tank 5 and the three-stage aerobic tank 6 for biological treatment; then passes through the three-stage sedimentation unit and the three-stage filtration unit for terminal treatment; finally enters the disinfection tank 9 for disinfection and discharge after meeting the standards.

[0105] The high-cold region sewage treatment method ensures the stable operation of the system in a low-temperature environment by accurately calculating and designing the thickness of the insulation layer 13 and the covering soil 15 layer, adopting a step-by-step treatment process, and optimizing the microbial growth environment. It also reduces operating costs and improves treatment efficiency through energy-saving design and intelligent control. Its superior economic benefits and environmental protection effects make it have significant advantages in sewage treatment applications in high-cold regions.

[0106] Compared with the existing high-cold area sewage treatment equipment 12, this high-cold area sewage treatment method has the following significant advantages:

[0107] No need for additional electric heating equipment. Traditional sewage treatment systems in high-cold areas usually require additional electric heating equipment to maintain the temperature of the treatment pool, especially in winter. However, through the precisely designed insulation layer 13 and the covering soil layer 15, the method can naturally maintain the temperature in the pool and avoid dependence on electric heating equipment. In this way, the system can significantly reduce energy consumption, especially in the cold winter of up to 6 months, and it is expected to save a lot of electricity. The lack of the need for an electric heating system means that the installation, maintenance, operation and update costs of electric heating equipment are greatly reduced, and the long-term operation and maintenance costs are greatly reduced.

[0108] It can also improve the activity of microorganisms and the treatment effect. In a low temperature environment, the activity of microorganisms will be inhibited, affecting the sewage treatment effect. By designing a suitable insulation layer 13 and a covering soil layer 15, the system temperature is ensured to be maintained within a suitable range of 10°C to 20°C, which is conducive to the growth and metabolism of microorganisms and ensures the efficient operation of biological treatment units (such as anaerobic tanks 4 and aerobic tanks 6). The stable temperature environment improves the ability of microorganisms to degrade organic matter, so that the system can still efficiently remove pollutants such as COD, ammonia nitrogen, and total phosphorus in cold climates, ensuring that the water quality meets the discharge standards.

[0109] Enhance system stability and reliability: In high-cold areas, sewage treatment equipment 12 and pipelines are prone to frost heave problems due to low temperatures, resulting in equipment damage. The thickness of the 15-layer covering soil is designed to be greater than or equal to the maximum frozen soil thickness, which can effectively prevent the impact of frozen soil and protect treatment structures and equipment from frost heave damage. This design improves the reliability and long-term stability of the system and reduces failures and downtime. By controlling the heat loss within the system, the system can operate stably under extremely cold conditions, avoiding the adverse effects of drastic temperature fluctuations on the treatment process, and improving the system's ability to cope with harsh environments.

[0110] Improve water treatment efficiency: This method adopts a step-by-step treatment process, passing the wastewater through three-stage grid pool 2, three-stage grit pool 3, three-stage anaerobic pool 4, three-stage anoxic pool 5, three-stage aerobic pool 6, three-stage sedimentation unit, three-stage filtration unit, and finally enters the disinfection pool 9 for treatment. This graded treatment method can effectively remove suspended matter, dissolved organic matter, nitrogen, phosphorus and other pollutants in the water to ensure that the effluent water quality meets the discharge standards. Different treatment units (such as anaerobic pool 4, aerobic pool 6, etc.) work together under suitable temperature and environment to improve the treatment effect of sewage, especially in high-cold areas, to prevent poor biological treatment effects due to low temperatures.

[0111] Strong environmental adaptability: Through insulation design and appropriate soil cover thickness of 15 layers, this method can effectively cope with long-term low temperature environment in high-cold areas, especially in areas with large temperature fluctuations. The system does not rely on external heat sources, reduces the demand for electricity, chemicals, etc., and is more environmentally friendly.

[0112] Reduced operating costs: By reducing energy consumption, reducing equipment update and maintenance costs, and avoiding reliance on electric heating equipment, the overall operating cost of the system is significantly lower than traditional methods. In high-altitude cold areas, the energy and maintenance cost savings can bring considerable economic benefits in the long run.

[0113] Increased service life: Insulation design not only improves process efficiency, but also extends system service life by protecting equipment from frost heave and low temperatures, reducing equipment failure and replacement costs caused by severe weather conditions.

[0114] Compared with the existing high-cold area sewage treatment equipment 12, this method can not only operate efficiently and stably in an extremely cold environment through the combination of thermal insulation design and sewage treatment process, but also significantly save energy and reduce consumption, improve treatment efficiency, extend equipment life, and reduce operating costs. Its intelligent control and green environmental protection characteristics make this method more sustainable and economical in the application of sewage treatment in high-cold areas, solving the problems of traditional methods in operating difficulties and excessive energy consumption in cold climates.

[0115] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A sewage treatment system for high-cold areas, characterized in that: It includes a pretreatment unit, a biological treatment unit and a terminal treatment unit which are sequentially connected and arranged in the heat preservation area; The pretreatment unit comprises three sections of grid tanks (2) and three sections of grit tanks (3), which are used to intercept solid impurities and inorganic particles in sewage step by step; the biological treatment unit comprises three sections of anaerobic tanks (4), three sections of anoxic tanks (5) and three sections of aerobic tanks (6), and organic matter degradation is achieved through staged treatment in the three sections of anaerobic tanks (4), three sections of anoxic tanks (5) and three sections of aerobic tanks (6); the terminal treatment unit comprises three sections of sedimentation tanks (7), three sections of filtration tanks (8) and a disinfection tank (9), which are used for solid-liquid separation and filtration and disinfection; A thermal insulation structure is also provided on the top of the thermal insulation zone, and the thermal insulation structure comprises at least a covering soil (15) layer and a thermal insulation layer (13).

2. A sewage treatment system for high-cold areas according to claim 1, characterized in that: The grid spacing of the three-stage grid pool (2) decreases step by step, and the spacing of the first-stage grid pool (2) is 30-50 mm, the spacing of the second-stage grid pool (2) is 10-20 mm, and the spacing of the third-stage grid pool (2) is 5-10 mm; The three-stage grit chamber (3) respectively adopts a combination of a horizontal grit chamber (3), an aerated grit chamber (3) and a cyclone grit chamber (3), and achieves sand particle separation through hydraulic control.

3. A sewage treatment system for high-cold areas according to claim 1, characterized in that: A sludge return channel is provided between the three-stage anaerobic tank (4) and the three-stage anoxic tank (5), and a mixed liquid return system is provided at the bottom of the three-stage aerobic tank (6) to return the nitrified liquid to the anoxic tank (5); The aeration intensity of the three-stage aerobic pool (6) decreases step by step, and the aeration volume of the first-stage aerobic pool (6) is 3-5m 3 / h, the aeration rate of the second aerobic pool (6) is 2-3m 3 / h, the aeration rate of the third aerobic pool (6) is 1-2m 3 / h.

4. A sewage treatment system for high-cold areas according to claim 1, characterized in that: The disinfection pool (9) is equipped with an ultraviolet disinfection device and an online water quality monitoring system for real-time monitoring of COD, ammonia nitrogen, total phosphorus and fecal coliform group indicators, so that the water is discharged after reaching the standards; The three-stage filtration unit consists of a sand filter, a fiber ball filter and an activated carbon filter, and the filtration accuracy is gradually improved to 0.5 to 1 micron.

5. A sewage treatment system for high-cold areas according to any one of claims 1-4, characterized in that: The three-stage grid pool (2), the three-stage grit pool (3), the three-stage anaerobic pool (4), the three-stage anoxic pool (5), the three-stage aerobic pool (6), the three-stage sedimentation pool (7), the three-stage filtration pool (8) and the disinfection pool (9) are arranged in sequence, and the heights gradually decrease, and an equipment arrangement area (11) is provided.

6. A sewage treatment system for alpine areas according to claim 1, characterized in that: The insulation layer (13) is composed of a composite of 20-30 mm spray-hard polyurethane foam and 35-45 mm lightweight aggregate insulation concrete, and the thickness of the covering soil (15) is at least greater than 2.0 m; Wherein, a composite thermal insulation block layer is also arranged on the outer side of the thermal insulation zone, the layer thickness of the composite thermal insulation block is greater than or equal to 240 mm, and a 20-30 mm rigid foam polyurethane board is filled in the middle.

7. A sewage treatment system for alpine areas according to claim 5, characterized in that: It also includes a plurality of wastewater pipes (1); the wastewater pipes (1) in the equipment layout area (11) are designed with gravity flow and have a slope greater than or equal to 0.5%; and the power equipment in the equipment layout area (11) is centrally arranged.

8. A method for operating sewage treatment in high-cold areas, applied to a sewage treatment system in high-cold areas according to any one of claims 1 to 7; characterized in that: include: Calculate the thickness of the insulation layer (13) and the thickness of the covering soil (15) according to the local air temperature, sewage water temperature and operation requirements; A pretreatment unit, a biological treatment unit and a terminal treatment unit are sequentially arranged in the heat preservation zone, and the pretreatment unit, the biological treatment unit and the terminal treatment unit are heat-insulated by a heat preservation layer (13) and a covering soil layer (15); The wastewater is gradually processed through the pretreatment unit, biological treatment unit and terminal treatment unit and then discharged after meeting the standards.

9. A method for sewage treatment in alpine areas according to claim 8, characterized in that: The thermal conductivity efficiency of the thermal insulation structure is less than 0.05 W / m 2 K, and the thickness of the covering soil (15) is greater than or equal to the maximum frozen soil thickness.

10. The method for sewage treatment in alpine areas according to claim 8, characterized in that: The wastewater is gradually processed through the pretreatment unit, biological treatment unit and terminal treatment unit, and the discharge after reaching the standards includes: The wastewater enters from the wastewater pipe (1) on the left side, and passes through three-stage grid tanks (2) and three-stage grit chambers (3) in sequence to complete preliminary pretreatment; Then it flows into three-stage anaerobic tank (4), three-stage anoxic tank (5) and three-stage aerobic tank (6) for biological treatment; Then it passes through three-stage sedimentation units and three-stage filtration units for terminal treatment; Finally, it enters the disinfection pool (9) and is discharged after being disinfected to the standard.

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