Village sewage treatment system and method with high efficiency, low energy consumption and effluent reaching Class IV surface water

Abstract

The present invention discloses a rural sewage treatment system and method with high efficiency, low energy consumption and effluent reaching Class IV surface water, comprising: a pretreatment module is provided with a sewage inlet and an outlet, and the outlet is sequentially connected to an enhanced biological treatment module and a advanced treatment module; the advanced treatment module is provided with a standard discharge outlet; an automatic control module is electrically connected to the pretreatment module, the enhanced biological treatment module and the advanced treatment module respectively, and can cooperate to control the pretreatment module, the enhanced biological treatment module and the advanced treatment module to carry out rural sewage treatment. It can meet high discharge standards with the minimum consumption of resources and energy, minimize the sludge production to the greatest extent, has flexible regulation and can realize unattended automatic control. The process performance leads the same type of process technology level in advanced countries in the world, filling the domestic blank in related fields.

Description

Technical Field

[0001] The present invention relates to the field of sewage treatment, and particularly to a rural sewage treatment system and method with high efficiency, low energy consumption and effluent reaching Class IV surface water quality standard. Background Art

[0002] The characteristics of low carbon-nitrogen ratio in rural sewage in China are prominent. The conventional biological nitrogen removal process has a low utilization efficiency of carbon sources in sewage, and the total nitrogen compliance depends on the addition of external carbon sources, resulting in high stable operation costs. Moreover, the influent organic matter concentration of rural sewage is too low and the water quality and quantity fluctuate greatly, so the traditional process design cannot operate stably in actual operation.

[0003] Currently, for rural sewage, the A / O, A 2 2 / O process or SBR process is mostly adopted, which can meet the discharge standard of Class A of the "Pollutant Discharge Standard for Municipal Wastewater Treatment Plants". However, with the introduction of many local standards, higher discharge requirements for environmental comprehensive treatment have been put forward. The drainage standard for rural sewage treatment needs to reach the requirements of Class IV standard of the "Surface Water Environment Quality Standard" (GB3838 - 2002). However, due to the problems of low nitrogen and phosphorus removal efficiency and the need to rely on a large amount of external carbon source addition in the traditional process composition, it not only fails to overcome the high operation cost, but also cannot fully ensure stable operation, resulting in the problem that the discharge cannot meet the discharge standard of the "Water Pollutant Discharge Standard for the Minjiang River and Tuojiang River Basins in Sichuan Province" (DB51 / 2311 - 2016) issued by Sichuan Province. Summary of the Invention

[0004] Based on the problems existing in the prior art, the purpose of the present invention is to provide a rural sewage treatment system and method with high efficiency, low energy consumption and effluent reaching Class IV surface water quality standard, which can solve the problems of high operation cost and unstable operation of existing rural sewage, resulting in the discharge not meeting the discharge standard of the "Water Pollutant Discharge Standard for the Minjiang River and Tuojiang River Basins in Sichuan Province" (DB51 / 2311 - 2016) issued by Sichuan Province.

[0005] The purpose of the present invention is achieved through the following technical solutions:

[0006] An embodiment of the present invention provides a rural sewage treatment system with high efficiency, low energy consumption and effluent reaching Class IV surface water quality standard, including:

[0007] A pretreatment module, an enhanced biological treatment module, a deep treatment module and an automatic control module; wherein,

[0008] The pretreatment module is provided with a sewage inlet and an outlet, and the outlet is sequentially connected to the enhanced biological treatment module and the deep treatment module;

[0009] The deep treatment module is provided with a qualified drainage outlet;

[0010] The automatic control module is electrically connected to the pretreatment module, the enhanced biological treatment module, and the advanced treatment module respectively, and can cooperate to control the pretreatment module, the enhanced biological treatment module, and the advanced treatment module to carry out rural sewage treatment.

[0011] An embodiment of the present invention also provides a rural sewage treatment method with high efficiency, low consumption and effluent reaching Class IV surface water. Using the system of the present invention, it includes the following steps:

[0012] Pretreatment step: Make the rural sewage to be treated enter the pretreatment module, and remove suspended solids, floating substances, gravel, etc. in the sewage through filtration and sedimentation. The effluent after pretreatment enters the enhanced biological treatment module;

[0013] Enhanced biological treatment step: After the sewage enters the enhanced biological treatment module, enhanced biological treatment is carried out in sequence, and the effluent after treatment enters the advanced treatment module;

[0014] Advanced treatment step: The incoming sewage is subjected to flocculation sedimentation, filtration and disinfection treatment in sequence.

[0015] It can be seen from the technical solutions provided by the present invention above that the rural sewage treatment system and method with high efficiency, low consumption and effluent reaching Class IV surface water provided by the embodiments of the present invention have the following beneficial effects:

[0016] Based on the sustainable denitrifying phosphorus removal process as a prototype, through scientific and reasonable design and optimization, it can meet high discharge standards with the minimum consumption of resources and energy, minimize the sludge production to the greatest extent, have flexible regulation and can achieve unattended automatic control. The process performance leads the similar process technology levels of advanced countries in the world, filling the domestic gap in related fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for description in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0018] Figure 1 It is a schematic diagram of the composition of the rural sewage treatment system provided by the embodiment of the present invention;

[0019] Figure 2 It is a schematic diagram of the enhanced biological treatment module of the rural sewage treatment system provided by the embodiment of the present invention;

[0020] Figure 3 It is a specific flow chart of the rural sewage treatment method provided by the embodiment of the present invention;

[0021] Figure 4 Specific flowchart of the rural sewage treatment method provided by the embodiment of the present invention;

[0022] Figure 1 The components corresponding to the marks are: 100 - pretreatment module; 200 - enhanced biological treatment module; 300 - advanced treatment module; 400 - automatic control module;

[0023] Figure 2 The components corresponding to the marks are: 1 - anaerobic tank; 2 - selector tank; 3 - anoxic tank; 4 - post - anoxic tank; 5 - aerobic tank; 6 - secondary sedimentation tank; 7 - reflux pump from aerobic tank to anoxic tank; 8 - reflux pump from aerobic tank to post - anoxic tank; 9 - valve; 10 - flowmeter; 11 - agitator; 12 - aeration device; 13 - blower; 14 - sludge reflux pump; 15 - excess sludge pump; 16 - influent pipe network. Specific embodiments

[0024] Next, in combination with the specific content of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention. The content not described in detail in the embodiments of the present invention belongs to the prior art well - known to those of ordinary skill in the art.

[0025] As Figure 1 shown, the embodiment of the present invention provides a rural sewage treatment system with high efficiency, low consumption and effluent reaching Class IV surface water, including:

[0026] A pretreatment module, an enhanced biological treatment module, an advanced treatment module and an automatic control module; among them,

[0027] The pretreatment module is provided with a sewage inlet and an outlet, and the outlet is sequentially connected to the enhanced biological treatment module and the advanced treatment module;

[0028] The advanced treatment module is provided with a qualified drainage outlet;

[0029] The automatic control module is electrically connected to the pretreatment module, the enhanced biological treatment module and the advanced treatment module respectively, and can cooperate to control the pretreatment module, the enhanced biological treatment module and the advanced treatment module to carry out rural sewage treatment.

[0030] The pretreatment module in the above - mentioned system includes:

[0031] A coarse grille and a fine grille connected in sequence. These two - stage grilles can remove large suspended solids and floating objects in the incoming sewage.

[0032] The pretreatment module in the above system further includes: an equalization tank, connected behind the fine grille. The equalization tank adopts a grit chamber containing a sludge hopper and a sludge discharge device, which can remove the grit in the sewage and balance the water quality and quantity.

[0033] As Figure 2 shown, in the above system, the enhanced biological treatment module includes:

[0034] An anaerobic tank, a selection tank, an anoxic tank, a post-anoxic tank and an aerobic tank connected in sequence. The volume ratios of the anaerobic tank, the selection tank, the anoxic tank, the post-anoxic tank and the aerobic tank are: 6-9:1:6-9:11-18:11-18. Such a setting of the volume ratio can maximize the role of each tank, so as to achieve the best overall effect;

[0035] Aeration devices are respectively arranged at the bottoms of the post-anoxic tank and the aerobic tank;

[0036] Stirring devices are arranged in the anaerobic tank, the selection tank, the anoxic tank and the post-anoxic tank;

[0037] The anoxic tank is connected back to the anaerobic tank through a mixed liquid return pipe provided with a control valve and a reflux pump;

[0038] The aerobic tank is connected back to the anoxic tank through a first return pipe provided with a reflux pump and a control valve;

[0039] The aerobic tank is connected back to the post-anoxic tank through a second return pipe provided with a reflux pump and a control valve.

[0040] In the above system, the enhanced biological treatment module further includes:

[0041] A secondary sedimentation tank, connected behind the aerobic tank. The secondary sedimentation tank is connected back to the selection tank through a pipeline provided with a sludge reflux pump;

[0042] The enhanced biological treatment module further includes:

[0043] An inlet pipe network, which is provided with a main pipeline. Three inlet branch pipes are respectively connected to the main pipeline. A control valve is arranged on each inlet branch pipe. Among the three inlet branch pipes, the first inlet branch pipe is connected to the anaerobic tank, the second inlet branch pipe is connected to the anoxic tank, and the third inlet branch pipe is connected to the aerobic tank.

[0044] In the above-mentioned enhanced biological treatment module, the anaerobic tank degrades the degradable substances in the sewage, produces volatile fatty acids (VFA) and releases phosphates; the selective tank further degrades the remaining COD to prevent the remaining COD from causing competition between the growth of heterotrophic microorganisms and the denitrifying phosphorus removal bacteria in the anoxic tank, and at the same time can effectively prevent sludge swelling and improve sludge sedimentation performance; the anoxic tank enriches denitrification and phosphorus removal, and uses internal carbon sources to remove phosphorus while denitrifying and removing nitrogen; the post-anoxic tank is equipped with aeration and stirring, which can achieve alternating control of anoxic and good nutrition according to water quality conditions; the aerobic tank is accurately aerated through the set aeration device to oxidize the ammonia nitrogen in the sewage into nitrate nitrogen.

[0045] In the above system, the deep processing module includes:

[0046] The flocculation sedimentation tank, sand filter tank and ultraviolet disinfection device are connected in sequence.

[0047] This deep treatment module is equipped with a flocculation sedimentation tank and a dosing room. The flocculation sedimentation tank solves the problem of instantaneous excess of SS and TP in the effluent caused by water quality fluctuations, and PAM and PAC are added in the dosing room to improve the flocculation effect. The sand filter tank further removes SS in the sewage. In special cases, the dosing room uses a pump pit to add activated carbon for emergency treatment. The ultraviolet disinfection device kills harmful microorganisms in the sewage through ultraviolet rays, so that the effluent meets the discharge standards.

[0048] In the pretreatment module, enhanced biological treatment module and deep treatment module of the above system, the pumps and fans used are all adjustable variable frequency pumps and fans, and the valves are all electric valves.

[0049] The automatic control module includes: a pretreatment control submodule, a biological control submodule and a depth control submodule;

[0050] The pretreatment control submodule is electrically connected to the pretreatment module, and can realize the joint control of the pump and the liquid level in the pretreatment module grid and the regulating tank; it can effectively control the liquid level difference before and after the grid to ensure the treatment effect, and at the same time divide the water level in the regulating tank into three different liquid level states of high, medium and low, and correspondingly control different water inlet flow rates to enter the enhanced biological treatment module;

[0051] The biological control submodule is electrically connected to the enhanced biological treatment module, and can realize the joint control of the water quality index, aeration volume and reflow ratio of each process in the enhanced biological treatment module; for example, the aeration volume and reflow ratio are adjusted according to the ammonia nitrogen concentration of the effluent from the aerobic pool, and if the ammonia nitrogen concentration of the effluent is too high, the aeration volume is increased to increase the reflow ratio from the aerobic pool to the post-anoxic pool to improve the nitrification effect;

[0052] The depth control sub-module, which is electrically connected to the depth treatment module, can achieve the joint control of the water quality of the effluent from the depth treatment module and the chemical dosage. For example, when the SS and total phosphorus in the effluent are poor, the chemical dosage can be increased to improve the treatment effect, effectively adjust the chemical dosage in the flocculation sedimentation tank, and control the dosage of activated carbon in the chemical dosing room to reduce the chemical consumption. This automatic control module can flexibly operate various processes according to the changes in the influent water quality and quantity, such as the denitrifying phosphorus removal process, the multi-stage A / O process, and the UCT process, etc., with flexible process adjustment.

[0053] See Figure 3 and Figure 4 , the embodiment of the present invention also provides a rural sewage treatment method with high efficiency, low consumption and effluent reaching Class IV surface water. Using the above system, it includes the following steps:

[0054] Pretreatment step: The rural sewage to be treated enters the pretreatment module, and the suspended solids, floating substances and gravel in the sewage are removed through filtration and sedimentation. The effluent after pretreatment enters the enhanced biological treatment module;

[0055] Enhanced biological treatment step: After the sewage enters the enhanced biological treatment module, enhanced biological treatment is carried out in sequence, and the effluent after treatment enters the depth treatment module;

[0056] Depth treatment step: The incoming sewage is subjected to flocculation sedimentation, filtration and disinfection treatment in sequence.

[0057] In the enhanced biological treatment step of the above method, the enhanced biological treatment includes:

[0058] At least one of denitrifying phosphorus removal treatment, multi-stage A / O treatment, and UCT treatment.

[0059] In view of the characteristics of rural sewage, the present invention provides a new type of rural sewage treatment system and method, which can treat rural sewage with sustainable denitrifying phosphorus removal technology. The whole system is divided into different modules with reasonable composition, and can meet high discharge standards with the least resources.

[0060] The following further describes the embodiments of the present invention in detail.

[0061] As Figure 1 shown, the embodiment of the present invention provides a rural sewage treatment system, which is sequentially connected by a pretreatment module, an enhanced biological treatment module and a depth treatment module. By using the automatic control module to coordinately control each module of the pretreatment module, the enhanced biological treatment module and the depth treatment module, unattended automatic operation is realized.

[0062] Furthermore, the above-mentioned pretreatment module includes a coarse grid and a fine grid, which can remove the suspended solids and floating substances in the incoming sewage and improve the subsequent treatment effect.

[0063] Furthermore, different pretreatment modules can be selected according to water quality and operation effect to ensure stable effluent compliance. For example, if the influent water quality and quantity fluctuate greatly, the above pretreatment module can add an equalization tank module. The equalization tank is equipped with a sludge hopper and a sludge discharge device to further remove gravel, improve the utilization rate of the subsequent biological tank volume, and reduce the treatment and disposal pressure of excess sludge.

[0064] The above enhanced biological treatment module adopts a flexible design and is composed of an anaerobic tank, a selection tank, an anoxic tank, a post-anoxic tank, and an aerobic tank in sequence. The volume ratio of the tanks is 6-9:1:6-9:11-18:11-18. For the typical layout of the enhanced biological treatment module, please refer to Figure 2 .

[0065] Furthermore, the anaerobic tank of the above enhanced biological treatment module mainly biologically treats the biodegradable COD in the influent water, generates volatile fatty acids (VFA) and releases phosphate, creating conditions for denitrifying phosphorus-removing bacteria. The selection tank further degrades the remaining COD, avoiding competition between the remaining COD and heterotrophic microorganisms in the anoxic tank for growth and denitrifying phosphorus-removing bacteria, and effectively preventing sludge bulking and improving sludge settling performance;

[0066] Furthermore, the anaerobic tank adopts a plug-flow reactor form to avoid sludge deposition, and a stirring device is provided in the selection tank. The anoxic tank adopts a plug-flow reactor form;

[0067] Furthermore, the denitrifying phosphorus-removing bacteria in the anoxic tank remove phosphorus while denitrifying with internal carbon source. The post-anoxic tank adjusts the operation mode according to the effluent ammonia nitrogen and total nitrogen indexes. When there is a risk of exceeding the standard for the effluent total nitrogen, it serves as a post-anoxic tank to further improve the denitrification effect. When there is a risk of exceeding the standard for the effluent ammonia nitrogen, it is used as an aerobic tank, and the DO can be controlled between 0.1-2 mg / L according to different water qualities. The aerobic tank is mainly used to oxidize ammonia nitrogen to nitrate nitrogen. An adjustable aeration device is provided in the aerobic tank, and the DO in the aerobic tank is generally between 2-4 mg / L;

[0068] Furthermore, the reflux ratio from the aerobic tank to the post-anoxic tank is 200%-500%. If the effluent ammonia nitrogen concentration is too high and there is a risk of exceeding the standard, the reflux ratio from the aerobic tank to the post-anoxic tank is increased;

[0069] Furthermore, the reflux ratio from the aerobic tank to the anoxic tank is 50%-300%. If there is a risk of exceeding the standard for the effluent nitrate nitrogen, the reflux ratio from the aerobic tank to the anoxic tank is increased;

[0070] Furthermore, the reflux ratio from the anoxic tank to the anaerobic tank is 50%-200%, which is adjusted according to the ORP of the anaerobic tank. If the ORP is too high, the reflux ratio is reduced;

[0071] Furthermore, the above-mentioned enhanced biological treatment module further includes: a secondary sedimentation tank. The sludge in the secondary sedimentation tank is pumped into the selection tank through a sludge return pump to supplement the sludge concentration of the system. The sludge return ratio from the secondary sedimentation tank to the selection tank is adjusted according to the change in the sludge concentration in the aerobic tank. The sludge discharge frequency of the excess sludge pump is regulated according to the indexes of the total nitrogen and total phosphorus in the effluent. When the phosphorus removal effect is poor, the sludge retention time (SRT) is reduced. When nitrification is poor, the sludge retention time (SRT) is increased to select an appropriate SRT to ensure the treatment effect.

[0072] Furthermore, due to the different sludge retention times (SRTs) of nitrifying bacteria and phosphorus-removing bacteria, during the operation in winter with low temperatures, in order to ensure the nitrification activity and maintain a relatively long sludge retention time (SRT) as much as possible, and to cope with the risk of possible excessive total phosphorus in the effluent, it is recommended that the process of the sewage treatment plant be as Figure 3 shown. A flocculation sedimentation tank can be equipped. When the phosphorus removal effect is poor, the dosage of polyaluminum chloride can be increased, so as to ensure that the total phosphorus meets the standard.

[0073] Furthermore, carbon source dosing sites are provided in the anaerobic tank, anoxic tank and aerobic tank. When the short-term low-load influent causes the operation effect of this process to deteriorate, such as when the denitrification effect is poor and there is a risk of excessive total nitrogen in the effluent, an appropriate amount of external carbon source can be supplemented to maintain the stability of the system performance.

[0074] Furthermore, the above-mentioned operation mode can realize the denitrifying phosphorus removal process. The enhanced biological treatment module of this system can be adjusted according to the change of the influent water quality, and can realize the flexible operation of multiple processes according to the change of the influent water quality. For example, the selection tank and the anaerobic tank can be combined and used as an anaerobic tank, the post-anoxic tank can be divided into an aerobic tank and an anoxic tank for use, and the reflux pump from the anoxic tank to the anaerobic tank is closed, then the multi-stage A / O process can be realized. In addition, when the anaerobic tank and the selection tank are used as an anaerobic tank, and the post-anoxic tank and the aerobic tank are combined and used as an aerobic tank, and the reflux from the aerobic tank to the post-anoxic tank is closed, it can be used as the UCT process. The process adjustment is flexible.

[0075] Furthermore, the above-mentioned advanced treatment module includes a chemical dosing room. When the effluent quality is poor in the short term, activated carbon is added by pumping into the pump pit for emergency treatment to ensure that the effluent quality meets the standard.

[0076] Furthermore, when there is a risk of excessive SS and total phosphorus in the effluent, the above-mentioned advanced treatment module can choose to increase a flocculation sedimentation device to solve the problem of instantaneous excessive SS in the effluent that may be caused by water quality fluctuations under the condition of ultra-high discharge standards. The effluent SS can be less than 10 mg / L.

[0077] Furthermore, the above-mentioned advanced treatment module includes a sand filter tank and an ultraviolet disinfection device, which can further remove SS in the sewage and disinfect the sewage with ultraviolet rays.

[0078] Furthermore, the above-mentioned automatic control module uses variable frequency adjustable pumps and fans used in the system, and uses electric valves for valves, so as to realize the joint control of the pump and the liquid level, so as to maintain a suitable liquid level difference before and after the grille to ensure the treatment effect;

[0079] Furthermore, the pump and liquid level in the regulating pool are controlled in a joint manner. Due to the large fluctuation of the influent water volume of village and town sewage, the liquid level in the regulating pool is divided into three different types: high, medium and low. Different influent flow rates are set through liquid level control to ensure the stable operation of the enhanced biological treatment module system.

[0080] Furthermore, the process water quality indexes, aeration volume and reflow ratio in the enhanced biological treatment module are jointly controlled, so that the aeration volume and reflow ratio are changed according to the changes in water quality indexes during the treatment process of each pool in the enhanced biological treatment module, thereby achieving the effect of high efficiency and low consumption.

[0081] Furthermore, the joint control of the effluent quality and dosage of the deep treatment module can be achieved. For example, when the effluent SS is too high, the dosage of polyaluminium chloride in the flocculation sedimentation tank can be increased to ensure the treatment effect.

[0082] Furthermore, the modular design allows for easy equipment combination, with equipment of different sizes designed according to water volume and quality, and equipped with an automatic control module to achieve unattended remote control;

[0083] The method for treating village and town sewage of the above system comprises the following steps:

[0084] Step 1, pretreatment: Municipal sewage is pretreated in the pretreatment module to remove suspended matter, floating matter and gravel in the sewage, and at the same time remove non-degradable organic matter such as lignin and cellulose in the sewage, improve the utilization rate of subsequent biological pool capacity and reduce the treatment and disposal pressure of residual sludge, so as to achieve subsequent stable treatment effect;

[0085] Step 2, enhanced biological treatment: The effluent after pretreatment enters the enhanced biological treatment module, which consists of six parts in sequence: anaerobic tank, selection tank, anoxic tank, post-anoxic tank, aerobic tank and secondary sedimentation tank. It adopts a flexible design to achieve different biochemical treatments;

[0086] Step 3, deep treatment: The effluent from enhanced biological treatment enters the deep treatment module, and the flocculation sedimentation tank is used to solve the problem of instantaneous excess of effluent SS caused by water quality fluctuations, and emergency treatment is carried out in the dosing room where activated carbon is added using a pump pit;

[0087] Automatic control treatment: Through the automatic control module, the joint control of the pump and the liquid level, the joint control of the process water quality index and the aeration volume and the reflow ratio, the joint control of the effluent water quality and the dosage, etc. are realized. Through these controls, the pretreatment module, the enhanced biological treatment module and the deep treatment module are coordinated and controlled.

[0088] Embodiment

[0089] Taking the treatment of a rural sewage treatment project by the system of the present invention as an example, the specific situation is as follows:

[0090] The influent flow rate of the project is 1200 m 3 / d. By using the system of the present invention and treating it with a full-process process combination, the hydraulic retention times HRT of the anaerobic tank, selection tank, anoxic tank, post-anoxic tank and aerobic tank are 3.5, 0.5, 4.0, 7.5 and 7.5 h respectively. Under the condition of an average temperature of 20°C and without adding external carbon sources, the effluent can meet the discharge standard of Beijing Standard A.

[0091] The influent water quality of the system of the present invention is shown in the following table:

[0092]

[0093] Compared with the existing processes, the system and method of the present invention have at least the following beneficial effects:

[0094] (1) Based on the sustainable denitrifying phosphorus removal process as a prototype, through scientific and reasonable design and optimization, it can meet the requirements of efficient and low-consumption effluent reaching Class IV surface water with the least resources, while maximizing the reduction of excess sludge and energy consumption;

[0095] (2) Adopting the modular design of the pretreatment module, enhanced biological treatment module, advanced treatment module and automatic control module, it can be flexibly regulated according to the influent and effluent water quality and quantity, and is very suitable for the application in the environment of rural sewage with low carbon-nitrogen ratio, low concentration and large fluctuations in water quality and quantity. Unattended automatic control can be realized through the automatic control module;

[0096] (3) It can adjust the operation process according to the influent load, and can flexibly operate a variety of processes according to the change of influent water quality, such as the denitrifying phosphorus removal process, multi-stage A / O and UCT processes, etc., and the process adjustment is flexible.

[0097] The system of the present invention can be applied to a wide range of process tank types, including: traditional A 2 O and its modified processes, oxidation ditch processes and modular equipment, etc. Among them, the transformation of the A 2 O process and the oxidation ditch process is mainly to re-divide the existing tanks or sections without changing the overall tank volume, so as to realize the denitrifying phosphorus removal process, reduce the dependence on carbon sources and improve the treatment effect.

[0098] As described above, it is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. An efficient and low-consumption rural sewage treatment system with effluent reaching Class IV surface water, characterized in that Comprising: A pretreatment module, an enhanced biological treatment module, an advanced treatment module, and an automatic control module; wherein, The pretreatment module is provided with a sewage inlet and a water outlet, and the water outlet is sequentially connected to the enhanced biological treatment module and the advanced treatment module; The advanced treatment module is provided with a qualified drainage outlet; The automatic control module is electrically connected to the pretreatment module, the enhanced biological treatment module, and the advanced treatment module respectively, and can coordinately control the pretreatment module, the enhanced biological treatment module, and the advanced treatment module to perform rural sewage treatment; The enhanced biological treatment module includes: An anaerobic tank, a selection tank, an anoxic tank, a post-anoxic tank, and an aerobic tank connected in sequence, and the volume ratio of the anaerobic tank, the selection tank, the anoxic tank, the post-anoxic tank, and the aerobic tank is 6-9:1:6-9:11-18:11-18; Aeration devices are respectively arranged at the bottom of the post-anoxic tank and the aerobic tank; Stirring devices are arranged in the anaerobic tank, the selection tank, the anoxic tank, and the post-anoxic tank; The anoxic tank is connected back to the anaerobic tank through a mixed liquor return pipe provided with a control valve and a reflux pump; The aerobic tank is connected back to the anoxic tank through a first return pipe provided with a reflux pump and a control valve; The aerobic tank is connected back to the post-anoxic tank through a second return pipe provided with a reflux pump and a control valve; The advanced treatment module includes: a flocculation sedimentation tank, a sand filter tank, and an ultraviolet disinfection device connected in sequence.

2. The rural sewage treatment system with high efficiency, low energy consumption and effluent meeting Class IV surface water quality according to claim 1, characterized in that, The pretreatment module includes: A coarse grille and a fine grille connected in sequence.

3. The rural sewage treatment system with high efficiency, low energy consumption and effluent meeting the Class IV surface water standard according to claim 2, characterized in that, The pretreatment module further includes: an adjustment tank, which is connected behind the fine grille.

4. The rural sewage treatment system with high efficiency, low energy consumption and effluent reaching Class IV surface water according to claim 1, characterized in that The enhanced biological treatment module further includes: A secondary sedimentation tank, which is connected behind the aerobic tank, and the secondary sedimentation tank is connected back to the selection tank through a sludge return pipe provided with a sludge reflux pump and a control valve; This enhanced biological treatment module further includes: An inlet pipe network, which is provided with a main pipeline, and three inlet branch pipes are respectively connected to the main pipeline. A control valve is arranged on each inlet branch pipe. Among the three inlet branch pipes, the first inlet branch pipe is connected to the anaerobic tank, the second inlet branch pipe is connected to the anoxic tank, and the third inlet branch pipe is connected to the aerobic tank.

5. The rural sewage treatment system with high efficiency, low energy consumption and effluent reaching Class IV surface water according to any one of claims 1 to 3, characterized in that, The automatic control module includes: A pretreatment control sub-module, a biological control sub-module, and a depth control sub-module; wherein, The pretreatment control sub-module, which is electrically connected to the pretreatment module, can realize the coordinated control of the grille and the pumps and liquid levels in the adjustment tank of the pretreatment module; The biological control sub-module, which is electrically connected to the enhanced biological treatment module, can realize the coordinated control of the water quality indexes, aeration volume, and reflux ratio in each process of the enhanced biological treatment module; The depth control sub-module, which is electrically connected to the advanced treatment module, can realize the coordinated control of the effluent water quality and the chemical dosage of the advanced treatment module.

6. An efficient and low-energy-consuming rural sewage treatment method with effluent reaching Class IV surface water, characterized in that, Using the system according to any one of claims 1 to 5, comprising the following steps: Pretreatment step: making the rural sewage to be treated enter the pretreatment module, removing suspended solids, floating objects, and gravel in the sewage through filtration, and the pretreated effluent enters the enhanced biological treatment module; Enhanced biological treatment step: after the sewage enters the enhanced biological treatment module, enhanced biological treatment is carried out in sequence, and the treated effluent enters the advanced treatment module; Advanced treatment steps: The incoming sewage is subjected to flocculation precipitation, filtration, and disinfection treatment in sequence.

7. The rural sewage treatment method according to claim 6, which can achieve surface class IV water with high efficiency and low energy consumption, is characterized in that In the enhanced biological treatment step of the method, the enhanced biological treatment includes: At least one of denitrifying phosphorus removal treatment, multi-stage A / O treatment, and UCT treatment.

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