A rural sewage denitrification and phosphorus removal system and a water treatment method

Abstract

The application relates to a rural sewage denitrification and phosphorus removal system and a water treatment method, wherein the rural sewage denitrification and phosphorus removal system comprises a lifting device, a purification device, a liquid collecting device, a backwashing waste liquid device, a gas source flushing device, a series connection pipeline device and a water distribution device; the purification reactor unit is respectively provided with a biological denitrification filler bed and a chemical phosphorus removal filler bed, and the liquid collecting device is used for receiving purified water; the water distribution device is arranged on the purification device and comprises a bottom uniform-flow water distributor used for uniformly distributing bottom inlet and outlet water and a residue cutting and water distribution assembly used for cutting residue and uniformly distributing top inlet and outlet water; the residue cutting and water distribution assembly comprises a top uniform-flow water distributor and a residue cutting and draining device located above the top uniform-flow water distributor. According to the rural sewage generation characteristics, the original water quality and water quantity of the sewage to be treated and the variable scene of high and low load, the application can flexibly and effectively remove nitrogen and / or phosphorus, and meet the needs of strengthening the removal of main pollutants such as carbon, nitrogen and phosphorus in rural areas.

Description

Technical Field

[0001] This application relates to the field of water treatment technology, and more specifically, to a rural sewage denitrification and phosphorus removal system and water treatment method. Background Technology

[0002] In existing centralized treatment processes for agricultural and domestic sewage, conventional methods only employ traditional A... 2 O or its variant processes rely on liquid reagents for enhanced phosphorus and nitrogen removal. However, they are difficult to enhance the removal of major pollutants such as carbon, nitrogen, and phosphorus, often resulting in poor nitrogen removal, poor phosphorus removal, or both. Furthermore, there are no effective pre-treatment measures such as anti-fouling and clogging layer cloth or graded interception device before the effluent or filtration unit. Inappropriate water distribution and chemical distribution methods can lead to turbulent and uneven flow. In particular, for buried chemical dosing and mixing reaction methods, it is difficult to conduct intuitive inspection and observation and facilitate switching operations. It is also difficult to adapt to the changing scenarios of raw water quality and quantity with high and low loads, or to meet the flexible requirements of unit combination control and switching for different effluent water quality targets.

[0003] Furthermore, the use of denitrification and phosphorus removal agents, such as purchasing solid agents or dissolving liquids on-site, or directly purchasing liquid agents, presents numerous limitations due to the remoteness or inconvenient transportation of agricultural wastewater treatment sites. These limitations include limited water sources for diluting solid agents, insufficient mixing and stirring equipment for dissolving agents, difficulties in transporting and unloading agents, or the lack of agent storage facilities. Additionally, agent dosing carries the risk of secondary pollution from direct contact with personnel or environmental leaks. Agricultural wastewater inspections are often intermittent, such as only once a day or once a week. Insufficient attention or untimely inspections can lead to agent depletion, directly impacting and reducing the denitrification and phosphorus removal efficiency of the agricultural wastewater system. This can result in the effluent failing to meet expected emission limits for nitrogen and phosphorus, potentially causing pollution exceeding standards in receiving water bodies, especially in closed or semi-closed rivers.

[0004] Agricultural wastewater often contains floating debris and slag. The lack of effective interception and drainage devices and uniform water flow distribution devices often causes problems such as short flow or poor flow. Summary of the Invention

[0005] The purpose of this application is to provide a rural wastewater denitrification and phosphorus removal system and water treatment method, which, by providing a denitrification and phosphorus removal cascaded packed bed device, is suitable for agricultural wastewater with a daily treatment capacity of 200m³. 3 Rural small-scale centralized sewage treatment technology with a capacity of / d or less, which can meet the requirements for enhanced removal of main pollutants such as carbon, nitrogen and phosphorus in sewage, and can also achieve interception and drainage of agricultural sewage and improvement of uniform influent flow.

[0006] To achieve the above objectives, in a first aspect, the present invention provides a rural sewage denitrification and phosphorus removal system, comprising: a lifting device, a purification device, a liquid collection device, a backwashing waste liquid device, an air source flushing device, a series pipeline device, and a water distribution device.

[0007] The lifting device is used to receive rural sewage and pump the raw water to the purification device. The purification device includes two purification reactor units for biological denitrification and chemical phosphorus removal purification of the raw water, respectively.

[0008] The purification reactor unit is equipped with a biological denitrification packing bed and a chemical phosphorus removal packing bed. The liquid collection device is used to receive purified water. The gas source flushing device can cooperate with the lifting device to backwash the purification device and the connecting pipeline. The backwash waste liquid device is used to receive the backwash wastewater generated by backwashing. The series pipeline device is set between different devices and two purification reactor units for branch transportation of rural sewage.

[0009] The water distribution device is installed on the purification device, including a bottom uniform flow water distributor for evenly distributing the bottom inlet and outlet water, and a slag interception and water distribution component for intercepting slag and evenly distributing the top inlet and outlet water.

[0010] The slag interception and water distribution assembly includes a top uniform water distributor and a slag interception and drainage device located above the top uniform water distributor.

[0011] In an optional embodiment, the purification reactor unit is a buried modular unit or an above-ground installed modular unit, including a purification reactor made of corrosion-resistant material, and the two purification reactors are respectively provided with a fixed bed packing layer for biological denitrification or chemical dephosphorization.

[0012] The fixed bed packing layer includes a phosphorus removal packing bed and a denitrification packing bed, both of which are slow-release packing materials and also have filtration functions. Relative to the flow direction of rural sewage, the phosphorus removal packing bed and the denitrification packing bed are connected in cascade, either preceding or inverting each other.

[0013] The phosphorus removal packing bed is filled with packing material with trivalent metal ions and composite phosphorus removal, which is made of iron-based, iron-carbon-based and iron-calcium-based materials, or a certain proportion of carbon fiber, graphene fiber or cucurbitaceous plant fiber bundles are added as a strong base material for implantation.

[0014] The denitrification packing bed is filled with packing material selected from autotrophic or heterotrophic materials that can provide good electron donors for denitrification reaction and composite denitrification, or a certain proportion of carbon fiber, graphene fiber or cucurbitaceous plant fiber bundles are added as one or more as a strong substrate material for implantation.

[0015] In an optional embodiment, internal gaps for water inlet and outlet are respectively provided on the top and bottom sides of the fixed bed packing layer, and the bottom flow equalizer and the slag interceptor and water distribution assembly are respectively arranged in the internal gaps.

[0016] The two purification reactors are respectively equipped with an upper water inlet pipe and a lower water inlet pipe, and the two purification reactors are respectively connected to an upper water outlet pipe and a lower water outlet pipe.

[0017] Each inlet and outlet pipe is equipped with a control valve located outside the purification reactor.

[0018] The upper water inlet pipe and the upper water outlet pipe, as well as the lower water inlet pipe and the lower water outlet pipe, are respectively arranged opposite to each other on both sides of the purification reactor.

[0019] In an optional embodiment, the lower water inlet pipe extends below the bottom uniform water distributor, and the extended end is positioned at the center of the bottom uniform water distributor.

[0020] The upper water inlet pipe extends above the slag trap and the extended end is placed at the center of the slag trap.

[0021] The connection point of the lower outlet pipe on the purification reactor is located between the fixed bed packing layer and the bottom uniform water distributor.

[0022] The connection point of the upper water outlet pipe on the purification reactor is located above the slag interceptor and drainer.

[0023] In an optional embodiment, the bottom uniform water distributor and the top uniform water distributor are both made of transparent PVC material, and both have a three-dimensional flat structure with the same cross-sectional shape as the purification reactor.

[0024] The bottom uniform water distributor and the top uniform water distributor each include an outlet plate and an inlet plate. Both the inlet plate and the outlet plate are provided with multiple annularly arranged water passage holes. The number of water passage holes on the outlet plate is greater than the number of water passage holes on the inlet plate. A hollow water distribution cavity is provided between the inlet plate and the outlet plate.

[0025] Raw water enters the uniform flow distributor from bottom to top or from top to bottom and flows into the purification packing through the water passage.

[0026] In an optional embodiment, the slag interceptor and the top uniform water distributor are positioned vertically opposite each other, and a gap of 5-10 cm is left between the bottom of the slag interceptor and the top uniform water distributor.

[0027] The slag interceptor and drainer is a double-layer filter structure with an inwardly curved and concave shape, including a primary slag interceptor and drainer layer at the top and a secondary slag interceptor and drainer layer at the bottom.

[0028] The primary slag intercepting and hydrophobic layer and the secondary slag intercepting and hydrophobic layer are stacked one on top of the other, and include a hollow hydrophobic cavity located between the two.

[0029] In an optional embodiment, the slag interceptor includes a first slag interceptor with a semi-circular vertical cross-section, or the slag interceptor includes a second slag interceptor with a crescent-shaped vertical cross-section.

[0030] The horizontal cross-sectional diameter of the primary slag-blocking and water-repellent layer on the first slag-blocking and water-repellent device is smaller than that of the secondary slag-blocking and water-repellent layer, with a diameter difference of 4-20cm.

[0031] The horizontal cross-sectional diameter of the primary slag intercepting and dewatering layer on the second slag intercepting and dewatering device is the same as the horizontal cross-sectional diameter of the secondary slag intercepting and dewatering layer;

[0032] Both the primary intercepting and drainage layer and the secondary intercepting and drainage layer include multiple annular segment bars spaced apart from each other and multiple straight segment bars evenly distributed circumferentially along the annular segment bars.

[0033] The gap between the straight and annular grid bars on the primary intercepting and drainage layer is greater than the gap between the straight and annular grid bars on the secondary intercepting and drainage layer.

[0034] Each set of the aforementioned slag interceptor and drainer is fixedly connected to the top of the purification reactor via an installation component.

[0035] In an optional embodiment, the slag interceptor includes multiple sets disposed above the top uniform water distributor, with the multiple sets of slag interceptors evenly spaced circumferentially relative to the top uniform water distributor.

[0036] In an optional embodiment, a control system is also included. The lifting device includes a lifting pump, a primary detection component, a lifting loop control valve, and a lifting liquid flow meter. The air source flushing device includes an air source device and an air source control valve. The liquid collection device includes a secondary detection component. The backwash waste liquid device includes a backwash waste liquid control valve. A short pipe and a short pipe control valve are provided between the lifting device and the liquid collection device. The control system is electrically connected to the electrical control equipment and control valves in different devices, as well as to the control valves in the purification device and the series pipe device.

[0037] Secondly, the present invention provides a water treatment method, which is carried out according to the rural sewage denitrification and phosphorus removal system described in the foregoing embodiments, including a variety of different operating modes to adapt to the changing scenarios of raw water quality and quantity with high and low loads of the water to be treated.

[0038] The operating modes include:

[0039] M1, When the raw water in the lifting device does not require treatment, the rural sewage in the lifting device flows directly into the collection device by gravity.

[0040] When the raw water denitrification or phosphorus removal requirements of the M2 lifting device only include the single requirement of enhancing water quality, the raw water is subjected to biological denitrification or chemical phosphorus removal purification treatment through one of the purification reactor units.

[0041] Meanwhile, in M2 mode, the following are included:

[0042] M21. When the dissolved oxygen (DO) in the effluent of the lifting device exceeds the empirical allowable content (e.g., when the DO allowable content is set to 3.5 mg / L), in order to prevent further cascading oxygen enrichment from the upper free fall of the self-purifying reactor unit, the effluent of the lifting device enters the purification reactor unit from bottom to top, provided that the suspended solids (SS) in the effluent of the lifting device do not exceed the empirical allowable concentration (e.g., when the SS allowable concentration is set to 40 mg / L).

[0043] M22. When the SS effluent from the lifting device exceeds the empirical allowable concentration (e.g., when the SS allowable concentration is set to 40 mg / L), and the DO effluent from the lifting device does not exceed the empirical allowable concentration (e.g., when the DO allowable concentration is set to 3.5 mg / L), in order to prevent turbidity from entering the bottom of the purification reactor unit and being difficult to remove from the packing through backwashing, and even if the SS turbidity enters the upper part of the purification reactor unit, it can still be intercepted by the upper part of the packing and can be efficiently removed from the packing through subsequent backwashing. The effluent from the lifting device enters the purification reactor unit from top to bottom.

[0044] When the raw water denitrification or phosphorus removal requirements in the M3 lifting device only include the single requirement of enhancing water quality, the raw water is subjected to biological denitrification or chemical phosphorus removal purification treatment through another purification reactor unit in the M2 mode.

[0045] In M3 mode, the following are also included:

[0046] M31. When the DO effluent from the lifting device exceeds the empirical allowable content (e.g., when the DO allowable content is set to 3.5 mg / L), in order to prevent further cascading and oxygen enrichment by the free fall at the top of the self-purifying reactor unit, the SS effluent from the lifting device enters the purification reactor unit from bottom to top, provided that the SS effluent from the lifting device does not exceed the empirical allowable concentration (e.g., when the SS allowable concentration is set to 40 mg / L).

[0047] M32, when the SS effluent from the lifting device exceeds the empirical allowable concentration (e.g., when the SS allowable concentration is set to 40 mg / L), and the DO effluent from the lifting device does not exceed the empirical allowable concentration (e.g., when the DO allowable concentration is set to 3.5 mg / L), in order to prevent turbidity from entering the bottom of the purification reactor unit and being difficult to remove from the packing through backwashing, and even if the SS turbidity enters the upper part of the purification reactor unit, it can still be intercepted by the upper part of the packing and can be efficiently removed from the packing through subsequent backwashing, the effluent from the lifting device enters the purification reactor unit from top to bottom;

[0048] When the total nitrogen and total phosphorus levels in the raw water of the M4 lifting device fail to meet the expected water quality, the raw water is simultaneously subjected to biological denitrification and chemical phosphorus removal purification treatment through two purification reactor units.

[0049] Meanwhile, in M4 mode, when the effluent DO in the lifting device exceeds the empirical allowable content (e.g., when the DO allowable content is set at 3.5 mg / L), to prevent further cascading oxygen enrichment due to the free fall at the top of the self-cleaning reactor unit, and provided that the effluent SS in the lifting device does not exceed the empirical allowable concentration (e.g., when the SS allowable concentration is set at 40 mg / L), the following two modes are used for treatment:

[0050] M41, the water from the lifting device enters the first-stage purification reactor unit from bottom to top, and the water from the first-stage purification reactor unit enters the second-stage purification reactor unit from top to bottom, and flows into the collection device after treatment.

[0051] M42, the water from the lifting device enters the first-stage purification reactor unit from bottom to top, and the water from the first-stage purification reactor unit enters the second-stage purification reactor unit from bottom to top, and after treatment, flows into the collection device.

[0052] Meanwhile, in M4 mode, when the effluent SS from the lifting device exceeds the empirically permissible concentration (e.g., when the permissible SS concentration is set at 40 mg / L), and the effluent DO from the lifting device does not exceed the empirically permissible concentration (e.g., when the permissible DO concentration is set at 3.5 mg / L), to prevent contaminants from entering the bottom of the purification reactor unit and becoming difficult to remove from the packing through backwashing, and even if SS contaminants enter the upper part of the purification reactor unit, they can still be intercepted by the upper part of the packing and efficiently removed from the packing through subsequent backwashing, the following two modes are used for treatment:

[0053] M43, the water from the lifting device enters the first-stage purification reactor unit from top to bottom, and the water from the first-stage purification reactor unit enters the second-stage purification reactor unit from bottom to top, and after treatment, flows into the collection device.

[0054] M44, the effluent from the lifting device enters the first-stage purification reactor unit from top to bottom, and the effluent from the first-stage purification reactor unit enters the second-stage purification reactor unit from top to bottom, and after treatment, flows into the collection device.

[0055] The rural sewage denitrification and phosphorus removal system and water treatment method of this invention further consume organic pollutants as endogenous denitrification electron donors, remove suspended COD and suspended solids through filter bed filtration, and collect solid floating waste through screen interception. It can achieve the goal of synergistic removal of nitrogen, phosphorus and suspended solids in the whole chain system for the purification of effluent water quality, with TN less than 20 mg / L, TN removal concentration exceeding 6 mg / L or TN removal rate exceeding 30%, TP less than 1.0 mg / L, TP removal concentration exceeding 0.6 mg / L or TP removal rate exceeding 50%, and SS less than 20 mg / L and SS removal concentration exceeding 20 mg / L.

[0056] By installing uniform water distributors on both the top and bottom sides of the packing bed, uniform water distribution can be achieved. At the same time, combined with the slag interceptor located at the top, floating debris and slag mixed in with rural sewage can be intercepted, achieving the technical effect of effective slag interception and drainage as well as uniform water distribution.

[0057] Meanwhile, the water treatment method in this invention can perform flexible and effective denitrification and / or phosphorus removal based on the characteristics of rural sewage generation and the varying water quality and volume of the raw water to be treated, thus meeting the enhanced removal needs of main pollutants such as carbon, nitrogen, and phosphorus in rural sewage.

[0058] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0059] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0060] Figure 1 This is a schematic diagram of the rural wastewater nitrogen and phosphorus removal system in this application;

[0061] Figure 2 This is a schematic diagram of the purification device.

[0062] Figure 3 A schematic diagram of the top and bottom uniform water distributors;

[0063] Figure 4Schematic diagrams of two different types of top-mounted slag interception and water distribution assemblies;

[0064] Figure 5 Schematic diagrams of two different types of slag traps and drainage devices;

[0065] Figure 6 A schematic diagram of the installation components for a slag trap and drainer;

[0066] Figure 7 A schematic diagram of the different slag interception and drainage layers of the slag interceptor and the assembled planar structure.

[0067] Figure 8 A schematic diagram of the planar structure of multiple slag traps and drainage devices at the top of the reactor;

[0068] Figure 9 This is a schematic diagram of the flow patterns under different modes in water treatment methods;

[0069] Figure 10 A schematic diagram illustrating the phosphorus removal efficiency of agricultural wastewater alone;

[0070] Figure 11 A schematic diagram illustrating the nitrogen removal efficiency of agricultural wastewater alone.

[0071] icon:

[0072] 1-Lifting device; 11-Unit to be purified; 12-Lifting pump;

[0073] 13-Lifting water supply pipeline components; 131-Main water supply pipeline; 132-Transport branch pipeline; 132a-Lifting liquid check valve; 132b-Lifting liquid flow meter; 133-Return liquid reduction pipeline; 133a-Lifting loop control valve;

[0074] 14 - Primary detection components;

[0075] 2-A type purified packed bed assembly; 21-A type purified reactor;

[0076] 22-A type component water inlet pipe; 221-A type lower water inlet fitting; 221a-A type lower water inlet control valve; 222-A type upper water inlet fitting; 222a-A type upper water inlet control valve;

[0077] 23-A type component outlet pipe; 231-A type lower outlet pipe fitting; 231a-A type lower outlet control valve; 232-A type upper outlet pipe fitting; 232a-A type upper outlet control valve; 24-A type fixed bed packing layer;

[0078] 3-B type purified packed bed assembly; 31-B type purified reactor;

[0079] 32-B type component water inlet pipe; 321-B type lower water inlet pipe fitting; 321a-B type lower water inlet control valve; 322-B type upper water inlet pipe fitting; 322a-B type upper water inlet control valve;

[0080] 33-B type component outlet pipe; 331-B type lower outlet pipe fitting; 331a-B type lower outlet control valve; 332-B type upper outlet pipe fitting; 332a-B type upper outlet control valve; 34-B type fixed bed packing layer;

[0081] 4-Liquid collection device; 41-Liquid collection unit container; 42-Secondary detection component;

[0082] 5-Backwash waste liquid device; 51-Backwash waste liquid unit container; 52-Waste liquid pipe fittings; 52a-Backwash waste liquid control valve;

[0083] 6-Air source flushing device; 61-Air source equipment; 62-Air flushing conveying pipe fittings; 62a-Air source control valve; 62b-Air flushing check valve;

[0084] 7-Series piping device; 70-Short-circuit flow manifold fitting; 70a-Short-circuit flow manifold control valve; 71-Liquid lifting air flushing fitting; 72-Liquid lifting air flushing branch fitting; 72a-Liquid lifting air flushing branch control valve; 73-Liquid outlet branch fitting; 74-Liquid outlet collection fitting; 74a-Liquid outlet collection control valve; 75-Purified drain fitting; 75a-Purified drain control valve;

[0085] 8-Water distribution device; 80-Top uniform water distributor; 81-Bottom uniform water distributor;

[0086] 82-Slag interceptor and drainer; 82a-First slag interceptor and drainer; 82b-Second slag interceptor and drainer; 821-Primary slag interceptor and drainer layer; 821a-Primary straight section bar; 821b-Primary annular section bar; 821c-First mounting center hole; 822-Secondary slag interceptor and drainer layer; 822a-Secondary straight section bar; 822b-Secondary annular section bar; 822c-Secondary mounting center hole; 83-Water passage hole;

[0087] 9-Installation component; 91-Horizontal base rod; 92-Vertical round rod; 93-Internal threaded nut. Detailed Implementation

[0088] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0089] In the description of this application, it should be noted that the terms "inner" and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing this application and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0090] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "setup" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0091] The rural sewage denitrification and phosphorus removal system and water treatment method in this application are mainly used for the treatment of rural sewage (i.e. agricultural waste). By setting up two different types of packing bed layers, the agricultural waste can be treated by biological denitrification or chemical phosphorus removal alone. At the same time, the agricultural waste can be passed through the two different types of packing bed layers in sequence for successive biological denitrification or chemical phosphorus removal.

[0092] By combining the necessary slag interception and water distribution structures, floating debris can be effectively intercepted before agricultural waste enters the packing bed from the top. After slag interception, water is evenly distributed through the water distributor, so that agricultural waste can also achieve a uniform water distribution effect when entering the packing bed from the bottom.

[0093] The rural sewage denitrification and phosphorus removal system of this invention can perform influent and effluent modes in multiple ways, which can meet the needs of actual application scenarios with varying raw water quality and water volume under high and low loads.

[0094] See Figure 1 The rural sewage denitrification and phosphorus removal system of the present invention includes: a lifting device 1, a purification device, a liquid collection device 4, a backwash waste liquid device 5, an air source flushing device 6, a series pipeline device 7, and a water distribution device 8.

[0095] The lifting device 1 is used to receive rural sewage and pump the raw water to the purification device. The purification device includes two purification reactor units for biological denitrification and chemical phosphorus removal purification of the raw water, respectively.

[0096] The purification reactor unit is respectively equipped with a biological denitrification packing bed and a chemical phosphorus removal packing bed. The liquid collection device is used to receive purified water. The gas source flushing device 6 can cooperate with the lifting device 1 to backwash the purification device and the connecting pipeline. The backwash waste liquid device 5 is used to receive the backwash wastewater generated by backwashing. The series pipeline device 7 is set between different devices and two purification reactor units for branch transportation of rural sewage.

[0097] The water distribution device 8 is installed on the purification device, including a bottom uniform water distributor 81 for evenly distributing the bottom inlet and outlet water, and a slag interception and water distribution component for intercepting slag and evenly distributing the top inlet and outlet water.

[0098] The slag interception and water distribution assembly includes a top uniform water distributor 80 and a slag interception and drainage device 82 located above the top uniform water distributor 80.

[0099] The lifting device 1 is specifically located at the very front of the process flow. It is used to receive rural sewage and pump the raw water to the purification device. The raw water is the original, untreated rural sewage.

[0100] Specifically, the lifting device 1 includes a purification unit 11, a lifting pump 12, a lifting water pipeline component 13, and a primary detection component 14. The purification unit 11 can be the biochemical secondary sedimentation tank section of the agricultural wastewater purification facility, that is, the section after secondary biological degradation treatment, or the effluent section after secondary biological degradation treatment.

[0101] The booster pump 12 is used to pump the liquid pressure in the unit to be purified 11 to the purification device. The booster water supply pipeline component 13 includes a main water supply pipeline 131 connected to the booster pump 12, a delivery branch pipeline 132, and a return liquid reduction pipeline 133. A booster check valve 132a and a booster flow meter 132b are installed on the delivery branch pipeline 132. The booster check valve 132a is used for one-way fluid control to prevent the backflow of the transported fluid from damaging the booster pump 12. The booster flow meter 132b is used to measure the flow rate of the purified sewage flowing through the delivery branch pipeline 132. A booster loop control valve 133a is installed on the return liquid reduction pipeline 133 to adjust the flow rate back to the unit to be purified 11, so as to adjust the flow rate on the delivery branch pipeline 132, that is, to adjust the amount of sewage sent to the purification device to the expected flow rate range. The pipe nodes of the main water supply pipeline 131, the delivery branch pipeline 132, and the return liquid reduction pipeline 133 are connected.

[0102] The primary detection component 14 can be equipped with a single-parameter sensor probe for suspended solids (SS) or dissolved oxygen (DO), or a dual-parameter sensor probe for both suspended solids and dissolved oxygen, and a digital display converter. This is used to dynamically detect the SS concentration and / or DO value within the purification unit 11. It can also be expanded to include a multi-parameter module for real-time detection of phosphates or nitrates, thereby enabling more real-time and accurate monitoring and evaluation of the biological denitrification effect and efficiency of nitrogen-containing pollutants, or the chemical phosphorus removal effect and efficiency of phosphorus-containing pollutants.

[0103] The purification unit comprises two purification reactor units, used for biological denitrification and chemical phosphorus removal purification of raw water, respectively. Each purification reactor unit is equipped with a biological denitrification packing bed and a chemical phosphorus removal packing bed.

[0104] To facilitate the explanation of the two purification reactor units of the purification device in this application, the explanation will be carried out in the form of specific distinction. The purification device specifically includes a type A purification packing bed assembly 2 and a type B purification packing bed assembly 3. The two purification packing bed assemblies constitute two purification reactor units. At the same time, the purification reactor units are either buried modular units or above-ground installed modular units, which have the advantages of short installation cycle, wide adaptability, multiple scheduling modes, fast efficiency, good decontamination effect, and long maintenance cycle.

[0105] Specifically, see Figure 2 The A-type purification packing bed assembly 2 includes an A-type purification reactor 21, an A-type assembly inlet pipe 22, and an A-type assembly outlet pipe 23. The A-type purification reactor 21 is the main purification unit of the packing bed and can be a reactor made of corrosion-resistant material with a cylindrical or cuboid structure. The A-type purification reactor 21 is equipped with an A-type fixed bed packing layer 24 for either biological denitrification or chemical dephosphorization.

[0106] A certain height of gap is reserved between the top of the type A fixed bed packing layer 24 and the top of the inner tank of the type A purification reactor 21, and between the bottom of the type A fixed bed packing layer 24 and the bottom of the inner tank of the type A purification reactor 21, forming an internal gap for the inlet and outlet of the reactor.

[0107] The bottom uniform water distributor 81 and the slag interception and water distribution component are respectively set in the internal gap. This arrangement can provide sufficient space for the inlet and outlet water in the reactor, and meet the requirements of slag interception and uniform water distribution.

[0108] The A-type component water inlet pipe 22 includes an A-type lower water inlet pipe 221, which extends below the bottom uniform water distributor 81 and has its extended end placed at the center of the bottom uniform water distributor 81. An A-type lower water inlet control valve 221a is provided on the A-type lower water inlet pipe 221. The valve is located outside the tank of the A-type purification reactor 21 for easy operation and maintenance.

[0109] The A-type component inlet pipe 22 also includes an A-type upper inlet pipe fitting 222. The A-type upper inlet pipe fitting 222 extends above the slag trap 82, with its extended end positioned at the center of the slag trap 82. This arrangement allows top-feed water to first reach the slag trap 82, ensuring effective slag removal before entering the top uniform water distributor 80 located below the slag trap 82. After uniform water distribution, the water then enters the A-type fixed bed packing layer 24. An A-type upper inlet control valve 222a is installed on the A-type upper inlet pipe fitting 222. The valve is located outside the A-type purification reactor 21 tank for convenient operation and maintenance.

[0110] The A-type component effluent pipe 23 is connected to the A-type purification reactor 21, including the A-type lower effluent pipe fitting 231 and the A-type upper effluent pipe fitting 232. The connection point of the A-type lower effluent pipe fitting 231 on the A-type purification reactor 21 is located between the A-type fixed bed packing layer 24 and the bottom uniform flow distributor 81, which can discharge the purified wastewater at the bottom. The A-type lower effluent pipe fitting 231 is equipped with an A-type lower effluent control valve 231a, which is located on the outside of the A-type purification reactor 21 tank for convenient operation and maintenance.

[0111] The connection point of the type A upper outlet pipe fitting 232 on the type A purification reactor 21 is located above the slag interceptor 82. It is equipped with a type A upper outlet control valve 232a. The valve is located on the outside of the tank of the type A purification reactor 21 for easy operation and maintenance.

[0112] The inlet pipe 22 and outlet pipe 23 of the type A component are respectively arranged on both sides of the type A purification reactor 21.

[0113] The above configuration allows for a relatively stable water flow that is either bottom-in, top-out, or top-in, bottom-out, enabling purification treatment in different water treatment methods.

[0114] Correspondingly, the Type B purification packing bed assembly 3 includes a Type B purification reactor 31, a Type B assembly inlet pipe 32, and a Type B assembly outlet pipe 33. The Type B purification reactor 31 is the main purification unit of the packing bed and can be a reactor made of corrosion-resistant material with a cylindrical or cuboid structure. The Type B purification reactor 31 is equipped with a Type B fixed bed packing layer 34 for either biological denitrification or chemical dephosphorization.

[0115] A certain height of gap is reserved between the top of the B-type fixed bed packing layer 34 and the top of the inner tank of the B-type purification reactor 31, and between the bottom of the B-type fixed bed packing layer 34 and the bottom of the inner tank of the B-type purification reactor 31, forming an internal gap for the inlet and outlet of the reactor.

[0116] The bottom uniform water distributor 81 and the slag interception and water distribution component are respectively set in the internal gap. This arrangement can provide sufficient space for the inlet and outlet water in the reactor, and meet the requirements of slag interception and uniform water distribution.

[0117] The B-type component water inlet pipe 32 includes a B-type lower water inlet pipe 321, which extends below the bottom uniform water distributor 81 and has its extended end placed at the center of the bottom uniform water distributor 81. A B-type lower water inlet control valve 321a is provided on the B-type lower water inlet pipe 321. The valve is located outside the tank of the B-type purification reactor 31 for easy operation and maintenance.

[0118] The B-type component inlet pipe 32 also includes a B-type upper inlet pipe fitting 322. The B-type upper inlet pipe fitting 322 extends above the slag trap 82, with its extended end positioned at the center of the slag trap 82. This arrangement allows top-feed water to first reach the slag trap 82, ensuring effective slag removal before entering the top uniform water distributor 80 located below the slag trap 82. After uniform water distribution, the water then enters the B-type fixed bed packing layer 34. A B-type upper inlet control valve 322a is installed on the B-type upper inlet pipe fitting 322. The valve is located outside the B-type purification reactor 31 tank for convenient operation and maintenance.

[0119] The B-type component effluent pipe 33 is connected to the B-type purification reactor 31, including a B-type lower effluent pipe fitting 331 and a B-type upper effluent pipe fitting 332. The connection point of the B-type lower effluent pipe fitting 331 on the B-type purification reactor 31 is located between the B-type fixed bed packing layer 34 and the bottom uniform flow distributor 81, which can discharge the purified wastewater at the bottom. A B-type lower effluent control valve 331a is provided on the B-type lower effluent pipe fitting 331. The valve is located on the outside of the tank of the B-type purification reactor 31 for convenient operation and maintenance.

[0120] The connection point of the upper outlet pipe fitting 332 of type B on the type B purification reactor 31 is located above the slag interceptor 82. A type B upper outlet control valve 332a is provided. The valve is located on the outside of the tank of type B purification reactor 31 for convenient operation and maintenance.

[0121] The inlet pipe 32 and outlet pipe 33 of the type B component are respectively arranged on both sides of the type B purification reactor 31.

[0122] In two opposing purification reactor units, if and only if the type A fixed bed packing layer 24 is selected to be equipped with biological denitrification packing, then the type B fixed bed packing layer 34 is selected to be equipped with chemical phosphorus removal packing with a different function; if and only if the type A fixed bed packing layer 24 is selected to be equipped with chemical phosphorus removal packing, then the type B fixed bed packing layer 34 is selected to be equipped with biological denitrification packing with a different function.

[0123] In other words, the phosphorus removal and denitrification packing beds set in the type A fixed bed packing layer 24 or the type B fixed bed packing layer 34 in this application can be connected in a pre- or inverted series configuration. Furthermore, the pre- or inverted series configuration is defined relative to the flow direction of rural sewage in the purification device, which can ensure the purification effect to the greatest extent while also providing effective flexibility.

[0124] The biological denitrification packing layer can be an autotrophic or heterotrophic driven slow-release packing material that provides good electron donors for the denitrification reaction and combines denitrification and filtration functions. The chemical phosphorus removal packing layer can use iron-based, iron-carbon-based, iron-calcium-based, or other slow-release packing materials with trivalent metal ions and combined phosphorus removal and filtration functions. Furthermore, a certain proportion of carbon fiber, graphene fiber, or cucurbitaceous plant fiber bundles can be added to both the biological denitrification packing layer and the chemical phosphorus removal packing layer as one or more of these as a bonding agent.

[0125] Both the Type A fixed bed packing layer 24 and the Type B fixed bed packing layer 34 have appropriate packing volumes to ensure that the designed hydraulic retention time of the Type A purification reactor 21 or the Type B purification reactor 31 is 25-120 minutes, allowing the packing material sufficient and effective contact reaction and purification time with pollutants such as nitrogen and phosphorus in the water. Both the biological denitrification packing bed and the chemical phosphorus removal packing bed are slow-release packing beds with filtration functions. They are gradually consumed during purification, and the final consumption period is generally 9-12 months. Therefore, only periodic replenishment of packing material is needed during inspections every 3-6 months. Alternatively, based on the evaluation of the purification effect, if it is lower than expected, enhanced replenishment can be initiated, especially before the arrival of winter in November, to stabilize the purification effect under unfavorable water inflow or environmental climatic conditions during winter. Therefore, they have the characteristic of long replenishment cycles, greatly reducing the difficulty of on-site maintenance and the workload of each replenishment.

[0126] See Figure 3 From the perspective of facilitating water distribution and drainage and slag interception, the bottom uniform water distributor 81 and the top uniform water distributor 80 are made of transparent PVC material and are both three-dimensional flat structures. Preferably, hollow water distribution cavities are provided inside the bottom uniform water distributor 81 and the top uniform water distributor 80. The hollow water distribution cavity mainly plays a buffering role. After the water enters the hollow water distribution cavity, it is buffered and flows out from the evenly distributed water passage holes 83.

[0127] Transparent materials are selected to facilitate visual inspection and observation of the packing layer. In order to ensure an effective water distribution area and make the influent more evenly distributed at the top or bottom of the reactor, the transverse cross-sections of the bottom uniform water distributor 81 and the top uniform water distributor 80 are the same as the transverse cross-section shape of the purification reactor.

[0128] When the cross-sections of the type A purification reactor 21 and the type B purification reactor 31 are circular or rectangular, the cross-sections of the bottom uniform flow distributor 81 and the top uniform flow distributor 80 also adopt the same circular or rectangular structural shape.

[0129] In order to ensure the effective installation of the uniform flow distributors, the surface cross-sectional area of ​​the bottom uniform flow distributor 81 and the top uniform flow distributor 80 is slightly smaller than the internal cross-sectional area of ​​the type A purification reactor 21 and the type B purification reactor 31.

[0130] The bottom uniform water distributor 81 and the top uniform water distributor 80 each include an outlet plate and an inlet plate, except that the outlet plate of the bottom uniform water distributor 81 is set facing upwards, while the outlet plate of the top uniform water distributor 80 is set facing downwards.

[0131] Multiple annularly arranged water passage holes 83 are provided on the inlet and outlet water plates. The number of water passage holes 83 on the outlet water plate is greater than the number of water passage holes 83 on the inlet water plate, and the diameter of the water passage holes 83 on the inlet water plate is greater than the diameter of the water passage holes 83 on the outlet water plate, thereby reducing the resistance of agricultural waste entering the hollow water distribution cavity.

[0132] The water distributor in this application specifically creates two effects through the inlet and outlet water plates. Firstly, the double-layer arrangement of the inlet and outlet water plates creates a certain filtration effect. Secondly, the cavity between the inlet and outlet water plates forms a hollow water distribution cavity. Agricultural waste enters the hollow water distribution cavity through the water passage holes 83 on the inlet water plate and is then discharged, forming a certain buffering effect, which can reduce the impact of fluctuations in the quality and quantity of agricultural waste on the stable water intake.

[0133] Raw water enters the hollow water distribution chamber of the uniform flow distributor from bottom to top or from top to bottom and flows into the purification packing through the water passage 83.

[0134] Of course, based on the setting of the water-draining and slag-blocking device, when the bottom inlet water flows through, the agricultural waste only needs to enter below the fixed bed packing layer, and enter the hollow water distribution cavity of the bottom uniform water distributor 81 through the water passage hole 83 on the lower water inlet plate surface. After water distribution, it enters the fixed bed packing layer for purification through the water passage hole 83 on the upper water outlet plate surface.

[0135] When water flows through the top inlet, the agricultural waste first flows to the top of the drainage and slag interceptor, where it is physically intercepted and drained. Then, it enters the hollow water distribution chamber of the top uniform water distributor 80 through the water passage 83 on the upper inlet plate, and then flows into the purification packing through the water passage 83 on the lower outlet plate to complete the slag interception and water distribution.

[0136] Based on the above-mentioned top water inlet flow, the interception and water distribution connection required is as follows: the interception drain 82 and the top equalizer 80 are positioned vertically opposite each other, which allows the intercepted agricultural wastewater to fall directly into the top equalizer 80, achieving a double buffer to stabilize the top water inlet.

[0137] A 5-10cm gap is left between the bottom of the slag interceptor 82 and the top water distributor 80. This gap provides a certain amount of space for the slag interceptor 82 to receive water, allowing the water entering the slag interceptor 82 to be evenly distributed through this gap, thereby fully dispersing the water flow from the top and ensuring the uniformity of the water flow from the top.

[0138] Combination Figures 4-8 From the perspectives of slag interception and filtration as well as water dispersion and drainage, the slag interceptor and drainer 82 is an inwardly curved and concave double-layer filter structure, including a primary slag interception and drainage layer 821 at the top and a secondary slag interception and drainage layer 822 at the bottom. The inwardly curved and concave double-layer filter can achieve a certain water collection effect, that is, it performs double-layer filtration through a curved sieve structure similar to that including grid bars.

[0139] The primary intercepting and draining layer 821 and the secondary intercepting and draining layer 822 are stacked one on top of the other, and include a hollow draining cavity between them. When water flows through from the top inlet, the agricultural waste flowing out from the upper inlet pipe is first intercepted by the primary intercepting and draining layer 821, which intercepts larger floating debris at the top of the primary intercepting and draining layer 821. Then, the agricultural waste after preliminary interception enters the hollow draining cavity, which not only drains water but also forms a buffer. Furthermore, the secondary intercepting and draining layer 822 further intercepts smaller floating debris, thereby minimizing the impurity content entering the fixed bed packing layer and extending the service life of the fixed bed packing layer.

[0140] In response to the different contents of floating impurities in agricultural wastewater, the slag interceptor 82 of this invention includes two different structural forms, which can intercept floating impurities respectively. The difference between the two different forms of slag interceptor 82 lies in the different areas of the interception and drainage area.

[0141] Specifically, the slag interceptor 82 includes a first slag interceptor 82a with a semi-circular vertical cross-section, or the slag interceptor 82 includes a second slag interceptor 82b with a crescent-shaped vertical cross-section.

[0142] The horizontal cross-sectional diameter of the primary slag intercepting and drainage layer 821 on the first slag intercepting and drainage device 82a is smaller than the horizontal cross-sectional diameter of the secondary slag intercepting and drainage layer 822, with a diameter difference of 4-20cm.

[0143] In other words, no water-passing grid or gap is set in the part with the difference in diameter. After the agricultural waste passes through the primary intercepting and drainage layer 821 with a bowl-shaped structure, there is a certain diffusion buffer inside the hollow drainage cavity. Then it passes through the secondary intercepting and drainage layer 822. This setting method is suitable for agricultural waste with less floating impurities and is also conducive to the scooping of intercepting impurities.

[0144] The horizontal cross-sectional diameter of the primary slag intercepting and drainage layer 821 on the second slag intercepting and drainage device 82b is the same as the horizontal cross-sectional diameter of the secondary slag intercepting and drainage layer 822.

[0145] After passing through the primary intercepting and drainage layer 821, which has a bowl-like structure, agricultural wastewater flows directly through the hollow drainage cavity into the secondary intercepting and drainage layer 822. This configuration is suitable for agricultural wastewater with a large content of floating impurities and can, to a certain extent, prevent the intercepting impurities from clogging the intercepting and drainage device 82.

[0146] From the perspective of hydrophobic structure, regardless of the structural form, the primary slag intercepting and hydrophobic layer 821 and the secondary slag intercepting and hydrophobic layer 822 on the slag intercepting and hydrophobic device 82 include multiple inner and outer spaced annular section bars and multiple straight section bars evenly distributed along the circumference of the annular section bars.

[0147] The gap between the primary straight section bar 821a and the primary annular section bar 821b on the primary slag intercepting and drainage layer 821 is greater than the gap between the secondary straight section bar 822a and the secondary annular section bar 822b on the secondary slag intercepting and drainage layer 822.

[0148] This enables the primary slag interception and drainage layer 821 to intercept slag with coarse particles through the grid, and the secondary slag interception and drainage layer 822 to further enhance the interception of slag with fine particles through the grid. It also prevents water accumulation caused by poor flow in the primary slag interception and drainage layer 821.

[0149] Each set of the slag interceptor 82 is anchored to the top of the purification reactor through the mounting component 9, and the first slag interceptor 82a and the second slag interceptor 82b are respectively provided with a first mounting center hole 821c and a second mounting center hole 822c.

[0150] Specifically, the mounting component 9 includes a horizontal base rod portion 91, a vertical round rod portion 92, and two pairs of internal threaded nuts 93. The vertical round rod portion 92 includes two segments of threaded rod spaced apart. During installation, the vertical round rod portion 92 passes through the first mounting center hole 821c of the first slag interceptor 82a or the first mounting center hole 821c of the second slag interceptor 82b, and the secondary slag interceptor 822 and the primary slag interceptor 821 are fixed to the vertical round rod portion 92 by the two pairs of internal threaded nuts 93.

[0151] This configuration facilitates the assembly and disassembly of the primary intercepting and drainage layer 821 and the secondary intercepting and drainage layer 822 on the mounting component 9, making operation and maintenance convenient and enabling offline manual flushing to remove solid floating waste such as slag attached to the primary intercepting and drainage layer 821 and the secondary intercepting and drainage layer 822.

[0152] In this invention, the slag interceptor and drainer 82 comprises multiple sets disposed above the top uniform flow distributor 80, with the multiple sets of slag interceptors and drainers 82 being symmetrically and evenly distributed circumferentially relative to the top uniform flow distributor 80. (Refer to...) Figure 8 In the example of four sets, agricultural waste flows to the center of the reactor tank through the upper inlet pipe fitting 222 of type A or the upper inlet pipe fitting 322 of type B. Then, the pipeline bends downward and is distributed into four branch pipes, which extend to the center of the slag interceptor and drainer 82, respectively, and perform slag interception, drainage and uniform water distribution.

[0153] Other components of rural wastewater nitrogen and phosphorus removal systems:

[0154] The liquid collection device 4 includes a liquid collection unit container 41 and a secondary detection component 42. The liquid collection unit container 41 is used to receive the treated liquid after purification from the type A purification packing bed component 2 or the type B purification packing bed component 3, or the liquid directly discharged by gravity from the unit to be purified 11, and then discharges it to the subsequent unit. The secondary detection component 42 is specifically equipped with a suspended solids single-parameter detection sensor probe and a digital display converter. It can also be expanded to include a phosphate or nitrate real-time detection multi-parameter module to dynamically detect the suspended solids (SS) concentration in the liquid collection unit container 41, or to simultaneously monitor the phosphate or nitrate concentration, thereby more real-time and accurate monitoring and evaluation of the biological denitrification effect and efficiency of nitrogen-containing pollutants, or the chemical phosphorus removal effect and efficiency of phosphorus-containing pollutants, providing a basis for different water treatment method operation modes.

[0155] The backwash waste liquid device 5 includes a backwash waste liquid unit container 51 and a waste liquid pipe 52. The waste liquid pipe 52 has a backwash waste liquid control valve 52a. The backwash waste liquid control valve 52a is located outside the tank of the backwash waste liquid unit container 51 for easy operation and maintenance.

[0156] The air source flushing device 6 includes an air source device 61 and an air flushing conveying pipe 62. The air flushing conveying pipe 62 is equipped with an air source control valve 62a and an air flushing check valve 62b. The air flushing check valve 62b serves as a one-way fluid control to prevent the conveying liquid phase fluid from the self-conveying branch pipe 132 from flowing back into the air source device 61 and causing it to be damaged.

[0157] The series pipeline device 7 includes a short-circuit flow pipe 70, a liquid lifting and air-flushing pipe 71, a liquid lifting and air-flushing branch pipe 72, a liquid outlet branch pipe 73, a liquid outlet collection pipe 74, and a purified liquid discharge pipe 75. The short-circuit flow pipe 70 is a gravity-fed pipe for the liquid to be purified from the purification unit 11 to the liquid collection unit container 41. The liquid lifting and air-flushing pipe 71 is connected in series with the conveying branch pipe 132 and the air-flushing conveying pipe 62, and then connected to the type A upper water inlet pipe 222 and the type A lower water inlet pipe 221. The liquid lifting and air-flushing pipe 71 and the type A upper water inlet pipe 222... 22. The lower inlet pipe 221 of type A is connected in series and then connected to the liquid lifting air flushing branch pipe 72; the outlet branch pipe 73 is connected in series with the lower outlet pipe 231 of type A, the upper outlet pipe 232 of type A, the lower inlet pipe 321 of type B, and the upper inlet pipe 322 of type B, and then connected in series with the liquid lifting air flushing branch pipe 72 and connected to the outlet collecting pipe 74; the outlet collecting pipe 74 is connected in series with the lower outlet pipe 331 of type B and the upper outlet pipe 332 of type B, and then connected to the purification drain pipe 75, and then enters the liquid collection unit container 41. A short-circuit flow control valve 70a, a liquid lifting air flushing branch control valve 72a, a liquid outlet collection control valve 74a, and a purified liquid discharge control valve 75a are respectively installed on the short-circuit flow pipe fitting 70, the liquid lifting air flushing branch pipe fitting 72, the liquid outlet collection control valve 74a, and the purified liquid discharge control valve 75a.

[0158] The invention also includes a control system. The lifting device 1 includes a lifting pump 12, a primary detection component 14, a lifting circuit control valve 133a, and a lifting liquid flow meter 132b. The air source flushing device 6 includes an air source device 61 and an air source control valve 62a. The liquid collection device 4 includes a secondary detection component 42. The backwash waste liquid device 5 includes a backwash waste liquid control valve 52a. A short pipe and a short pipe control valve are provided between the lifting device 1 and the liquid collection device 4. The control system is electrically connected to the electrical control equipment and control valves in different devices, as well as to the control valves in the purification device and the series pipe device 7.

[0159] Through the electrical connections between the aforementioned control system and various control valves and electrical control equipment, automated control can be achieved, enabling intelligent operation. Simultaneously, it can provide specific reference criteria for different water treatment methods.

[0160] This invention also provides a water treatment method based on the rural sewage denitrification and phosphorus removal system described above, including various operating modes to adapt to scenarios with varying raw water quality, quantity, and load conditions. (See also...) Figure 9 The following describes the application of Type A purification packing bed assembly 2 as a biological denitrification packing bed, and Type B purification packing bed assembly 3 as a chemical phosphorus removal packing bed. Operating modes include:

[0161] In M1 mode, when the water quality of the effluent from the lifting device 1 meets the expected water quality and there is no further need to enhance the water quality for denitrification and phosphorus removal, the lifting device 1 flows directly into the collection device 4 by gravity. Both the type A purification packing bed assembly 2 and the type B purification packing bed assembly 3 are in offline non-reactive conditions.

[0162] In M2 mode, when the raw water denitrification or phosphorus removal demand detected by the primary detection component 14 in the lifting device 1 only includes its single enhanced water quality improvement demand, the raw water is subjected to biological denitrification or chemical phosphorus removal purification treatment through one of the purification reactor units.

[0163] Specifically, in the M21 and M22 modes, when the total nitrogen or total phosphorus index of the effluent from the lifting device 1 is detected to meet the expected water quality, and the denitrification or phosphorus removal requirements only include the single enhanced water quality improvement requirement, if the total nitrogen requirement is met, only the phosphorus removal water quality improvement requirement is needed; or if the phosphorus removal requirement is met, only the ammonia removal water quality improvement requirement is needed, the type A purification packing bed assembly 2 participates in the reaction mode, while the type B purification packing bed assembly 3 is in the offline non-reaction mode.

[0164] In the M21 mode, when the secondary detection component 42 detects that the DO effluent from the lifting device 1 exceeds the empirical allowable content (e.g., when the DO allowable content is set to 3.5 mg / L), in order to prevent further water drop and oxygen enrichment from the upper free fall of the type A purification packing bed assembly 2, under the condition that the SS effluent from the lifting device 1 does not exceed the empirical allowable concentration (e.g., when the SS allowable concentration is set to 40 mg / L), the type A purification packing bed assembly 2 of the water effluent from the lifting device 1 adopts an upward flow state, that is, the bottom-up mode is more suitable. The lifting device 1 enters water through the bottom of the type A purification packing bed assembly 2, reacts and exits water from the top of the type A purification packing bed assembly 2, and then flows into the liquid collection device 4. That is, the flow of the type A purification packing bed assembly 2 adopts the bottom-in and top-out method.

[0165] In M22 mode, when the secondary detection component 42 detects that the SS concentration in the effluent from the lifting device 1 exceeds the empirical allowable concentration (e.g., when the SS allowable concentration is set to 40 mg / L), and simultaneously detects that the DO concentration in the effluent from the lifting device 1 does not exceed the empirical allowable concentration (e.g., when the DO allowable concentration is set to 3.5 mg / L), to prevent contaminants from entering the bottom of the type A purification packing bed assembly 2 and being difficult to backwash out of the type A purification packing bed assembly 2 system, while SS contaminants do enter the type A purification system... The upper part of the packing bed assembly 2 can still be intercepted by the upper part of the packing, and can be efficiently removed from the A-type purification packing bed assembly 2 system by subsequent pulse backwashing in a counter-current manner from bottom to top. The A-type purification packing bed assembly 2 of the water outlet of the lifting device 1 can adopt a downward flow state, that is, a top-down mode, which is more suitable. The lifting device 1 enters the A-type purification packing bed assembly 2 through the top, reacts and exits the A-type purification packing bed assembly 2 through the bottom, and then flows into the liquid collection device 4. That is, the flow of the A-type purification packing bed assembly 2 adopts the top-in and bottom-out method.

[0166] In M3 mode, when the raw water denitrification or phosphorus removal requirements in the booster unit 1 only include the single requirement of enhancing water quality, the raw water is subjected to biological denitrification or chemical phosphorus removal purification treatment through another purification reactor unit in M2 mode.

[0167] Specifically, in the M31 and M32 modes, when the total nitrogen or total phosphorus index of the effluent from the lifting device 1 is detected to meet the expected water quality, and the denitrification or phosphorus removal requirements only include the single enhanced water quality improvement requirement, if the total nitrogen requirement is met, only the phosphorus removal water quality improvement requirement is needed; or if the phosphorus removal requirement is met, only the ammonia removal water quality improvement requirement is needed, the type B purification packing bed assembly 3 participates in the reaction mode, while the type A purification packing bed assembly 2 is in the offline non-reaction mode.

[0168] In the M31 mode, when the secondary detection component 42 detects that the DO effluent from the lifting device 1 exceeds the empirical allowable content (e.g., when the DO allowable content is set to 3.5 mg / L), in order to prevent further water drop and oxygen enrichment from the upper free fall of the unit B-type purification packing bed assembly 3, under the condition that the SS effluent from the lifting device 1 does not exceed the empirical allowable concentration (e.g., when the SS allowable concentration is set to 40 mg / L), the B-type purification packing bed assembly 3 of the water effluent from the lifting device 1 adopts an upward flow state, that is, the bottom-up mode is more suitable. The lifting device 1 enters water through the bottom of the B-type purification packing bed assembly 3, reacts and exits water from the top of the B-type purification packing bed assembly 3, and then flows into the liquid collection device 4. That is, the flow of the A-type purification packing bed assembly 2 adopts the bottom-in and top-out method.

[0169] In M32 mode, when the secondary detection component 42 detects that the SS concentration in the effluent from the lifting device 1 exceeds the empirical allowable concentration (e.g., when the SS allowable concentration is set to 40 mg / L), and simultaneously detects that the DO concentration in the effluent from the lifting device 1 does not exceed the empirical allowable concentration (e.g., when the DO allowable concentration is set to 3.5 mg / L), to prevent contaminants from entering the bottom of the type B purification packing bed assembly 3 and being difficult to backwash out of the type B purification packing bed assembly 3 system, even if SS contaminants enter the type B purification... The upper part of the packing bed assembly 3 can still be intercepted by the upper part of the packing, and can be efficiently removed from the B-type purification packing bed assembly 3 system by subsequent pulse backwashing in a counter-current manner from bottom to top. The B-type purification packing bed assembly 3 of the water outlet of the lifting device 1 can adopt a downward flow state, that is, a top-down mode, which is more suitable. The lifting device 1 enters the B-type purification packing bed assembly 3 through the top, reacts and exits the B-type purification packing bed assembly 3 through the bottom, and then flows into the liquid collection device 4. That is, the flow of the B-type purification packing bed assembly 3 adopts the top-in and bottom-out method.

[0170] In M4 mode, when the total nitrogen and total phosphorus levels in the raw water of the lifting device 1 cannot meet the expected water quality, the raw water is simultaneously subjected to biological denitrification and chemical phosphorus removal purification treatment through two purification reactor units.

[0171] Meanwhile, in M4 mode, when the effluent DO in lifting device 1 exceeds the empirical allowable concentration (e.g., when the DO allowable concentration is set at 3.5 mg / L), to prevent further cascading oxygen enrichment due to the free fall at the top of the self-cleaning reactor unit, and under the condition that the effluent SS in lifting device 1 does not exceed the empirical allowable concentration (e.g., when the SS allowable concentration is set at 40 mg / L), it is treated through the following two modes:

[0172] Specifically, in the M41 and M42 modes, when the total nitrogen and total phosphorus indicators of the effluent from the lifting device 1 are detected by the primary detection component 14 as failing to meet the expected water quality, and denitrification and phosphorus removal still need to be processed through the A-type purification packing bed component 2 and the B-type purification packing bed component 3 in order to enhance the dual requirements of water quality improvement, both the A-type purification packing bed component 2 and the B-type purification packing bed component 3 participate in the reaction.

[0173] In the M41 mode, the lifting device 1 enters water through the bottom of the type A purification packing bed assembly 2, reacts and exits water from the top of the type A purification packing bed assembly 2, and then flows into the top of the type B purification packing bed assembly 3. After reacting and exiting water from the bottom of the type B purification packing bed assembly 3, it flows into the liquid collection device 4. That is, the flow of the type A purification packing bed assembly 2 and the type B purification packing bed assembly 3 adopts the method of bottom inlet and top outlet for type A purification packing bed assembly 2 and top inlet and bottom outlet for type B purification packing bed assembly 3, respectively.

[0174] In the M42 mode, the lifting device 1 enters water through the bottom of the type A purification packing bed assembly 2, reacts and exits water from the top of the type A purification packing bed assembly 2, and then flows into the bottom of the type B purification packing bed assembly 3. After reacting and exiting water from the top of the type B purification packing bed assembly 3, the water flows into the collection device 4. That is, the flow of the type A purification packing bed assembly 2 and the type B purification packing bed assembly 3 adopts the bottom-in and top-out method of type A purification packing bed assembly 2 and type B purification packing bed assembly 3, respectively.

[0175] Meanwhile, in M4 mode, when the SS effluent from lifting device 1 exceeds the empirically permissible concentration (e.g., when the permissible SS concentration is set to 40 mg / L), and the DO effluent from lifting device 1 does not exceed the empirically permissible concentration (e.g., when the permissible DO concentration is set to 3.5 mg / L), to prevent contaminants from entering the bottom of the purification reactor unit and being difficult to remove from the packing through backwashing, and even if SS contaminants enter the upper part of the purification reactor unit, they can still be intercepted by the upper part of the packing and can be efficiently removed from the packing through subsequent backwashing, the following two modes are used for treatment:

[0176] Specifically, when the secondary detection component 42 detects that the SS concentration in the effluent from the lifting device 1 exceeds the empirical allowable concentration (e.g., when the SS allowable concentration is set to 40 mg / L), and simultaneously detects that the DO concentration in the effluent from the lifting device 1 does not exceed the empirical allowable concentration (e.g., when the DO allowable concentration is set to 3.5 mg / L), in order to prevent turbidity from entering the bottom of the type A purification packing bed assembly 2 and being difficult to backwash out of the type A purification packing bed assembly 2 system, and even if the SS turbidity enters the upper part of the type A purification packing bed assembly 2, it can still be intercepted by the upper part of the packing and can be efficiently removed out of the type A purification packing bed assembly 2 system through subsequent pulse backwashing in a counter-current manner from bottom to top, it is more suitable for the type A purification packing bed assembly 2 of the effluent from the lifting device 1 to adopt a downward flow state, i.e., a top-down mode.

[0177] In the M43 mode, the water from the lifting device 1 enters through the top of the type A purification packing bed assembly 2, reacts and exits from the bottom of the type A purification packing bed assembly 2, and then flows into the bottom of the type B purification packing bed assembly 3. After reacting and exiting from the top of the type B purification packing bed assembly 3, the water flows into the collection device 4. That is, the flow of the type A purification packing bed assembly 2 and the type B purification packing bed assembly 3 adopts the method of top inlet and bottom outlet for type A purification packing bed assembly 2 and bottom inlet and top outlet for type B purification packing bed assembly 3, respectively.

[0178] In the M44 mode, the water from the lifting device 1 enters through the top of the type A purification packing bed assembly 2, reacts and exits from the bottom of the type A purification packing bed assembly 2, and then flows into the top of the type B purification packing bed assembly 3. After reacting and exiting from the bottom of the type B purification packing bed assembly 3, the water flows into the collection device 4. That is, the flow of the type A purification packing bed assembly 2 and the type B purification packing bed assembly 3 adopts the method of top inlet and bottom outlet for type A purification packing bed assembly 2 and top inlet and bottom outlet for type B purification packing bed assembly 3, respectively.

[0179] It should be noted that, by opening and closing necessary valves and devices, three flushing and recovery modes can be adopted: individual air source flushing, individual raw water flushing, and combined air and water source flushing. Furthermore, individual or coordinated synchronous flushing and waste liquid collection can be performed on the Type A purification packing bed assembly 2, Type B purification packing bed assembly 3, and pipeline facilities. Primary detection component 14 and secondary detection component 42 assist in observation and feedback early warning to activate the air source flushing device 6, or to activate the flushing source system at a fixed periodic frequency to ensure the long-term stable operation of the system.

[0180] Figures 10-11 This is an example of the removal efficiency when the main reaction unit for phosphorus removal or denitrification of agricultural wastewater is used alone, and the hydraulic retention time is 35 to 45 minutes.

[0181] As can be seen from the examples, the rural wastewater nitrogen and phosphorus removal system and water treatment method of this invention can effectively achieve the nitrogen and phosphorus purification effluent water quality target of TN less than 20 mg / L (or TN removal concentration exceeding 6 mg / L, or TN removal rate exceeding 30%) and TP less than 1.0 mg / L (or TP removal concentration exceeding 0.6 mg / L, or TP removal rate exceeding 50%). Furthermore, through deep filtration and net interception using a fine filter bed of type A or / and type B purification packing, a synergistic multi-pollutant removal effect of SS less than 20 mg / L or SS removal concentration exceeding 20 mg / L can be achieved in the effluent.

[0182] It should be noted that, where there is no conflict, the features in the embodiments of this application can be combined with each other.

[0183] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A rural wastewater nitrogen and phosphorus removal system, characterized in that, include: Lifting device, purification device, liquid collection device, backwash waste liquid device, air source flushing device, series pipeline device, and water distribution device; The lifting device is used to receive rural sewage and pump the raw water to the purification device. The purification device includes two purification reactor units. One purification reactor unit is equipped with a biological denitrification packing bed for biological denitrification purification of rural sewage, and the other purification reactor unit is equipped with a chemical phosphorus removal packing bed for chemical phosphorus removal purification of rural sewage. The liquid collection device is used to receive purified water. The air source flushing device can cooperate with the lifting device to backwash the purification device and the connecting pipeline. The backwash waste liquid device is used to receive the backwash wastewater generated by backwashing. The series pipeline device is set between different devices and between two purification reactor units for branch transportation of rural sewage. The water distribution device is installed on the purification device, including a bottom uniform flow water distributor for evenly distributing the bottom inlet and outlet water, and a slag interception and water distribution assembly for intercepting slag and evenly distributing the top inlet and outlet water. The slag interception and water distribution assembly includes a top uniform flow water distributor and a slag interception and water drainage device located above the top uniform flow water distributor. The purification reactor unit includes a purification reactor made of corrosion-resistant material. The two purification reactors are respectively provided with fixed bed packing layers. One fixed bed packing layer includes a biological denitrification packing bed, and the other fixed bed packing layer includes a chemical phosphorus removal packing bed. The fixed bed packing layer has internal gaps for water inlet and outlet on both the top and bottom sides, and the bottom flow equalizer and the slag interceptor and water distribution assembly are respectively installed in the internal gaps. Both of the purification reactors are equipped with an upper water inlet pipe and a lower water inlet pipe, and both of the purification reactors are connected to an upper water outlet pipe and a lower water outlet pipe. Each inlet and outlet pipe is equipped with a control valve located outside the purification reactor. The upper water inlet pipe and the upper water outlet pipe, as well as the lower water inlet pipe and the lower water outlet pipe, are respectively arranged opposite to each other on both sides of the purification reactor; Both the bottom and top uniform water distributors are made of transparent PVC material, have a three-dimensional flat structure, and their transverse cross-sectional shape is the same as that of the purification reactor. Both the bottom and top uniform water distributors include an outlet plate and an inlet plate. Both the inlet and outlet plates are provided with multiple annularly arranged water passage holes. The number of water passage holes on the outlet plate is greater than the number of water passage holes on the inlet plate. A hollow water distribution cavity is provided between the inlet and outlet plates. The slag interceptor and the top uniform water distributor are positioned vertically opposite each other, and a gap of 5-10cm is left between the bottom of the slag interceptor and the top uniform water distributor. The slag interceptor and water drainer is an inwardly curved and concave double-layer filter structure, including a primary slag interceptor and water drain layer at the top, a secondary slag interceptor and water drain layer at the bottom, and a hollow water drain cavity between the two. The primary intercepting and dewatering layer and the secondary intercepting and dewatering layer are arranged in an upper and lower stacked manner. Multiple sets of slag interceptors and drainers are provided, and the multiple sets of slag interceptors and drainers are symmetrically and evenly distributed around the top uniform water distributor. The rural wastewater nitrogen and phosphorus removal system includes a variety of different operating modes to adapt to scenarios with varying raw water quality, water volume, and high and low loads. It also includes a control system. The lifting device includes a lifting pump, a primary detection component, a lifting circuit control valve, and a lifting liquid flow meter. The air source flushing device includes an air source device and an air source control valve. The liquid collection device includes a secondary detection component. The backwash waste liquid device includes a backwash waste liquid control valve. A short pipe and a short pipe control valve are provided between the lifting device and the liquid collection device. The control system is electrically connected to the electrical control equipment and control valves in different devices.

2. The rural wastewater nitrogen and phosphorus removal system according to claim 1, characterized in that, The purification reactor unit is either a buried modular unit or an above-ground installed modular unit; Both the biological denitrification packing bed and the chemical phosphorus removal packing bed have slow-release and filtration functions. Relative to the flow direction of rural sewage, the chemical phosphorus removal packing bed and the biological denitrification packing bed are connected in series, either as a pre- or post-position of each other.

3. The rural wastewater nitrogen and phosphorus removal system according to claim 1, characterized in that, The lower water inlet pipe extends below the bottom uniform water distributor, and the extended end is located at the center of the bottom uniform water distributor. The upper water inlet pipe extends above the slag trap and the extended end is located at the center of the slag trap. The connection point of the lower outlet pipe on the purification reactor is located between the fixed bed packing layer and the bottom uniform water distributor. The connection point of the upper water outlet pipe on the purification reactor is located above the slag interceptor and drainer.

4. The rural wastewater nitrogen and phosphorus removal system according to claim 1, characterized in that, Raw water enters the uniform flow distributor from bottom to top or from top to bottom and flows into the purification packing through the water passage.

5. The rural wastewater nitrogen and phosphorus removal system according to claim 1, characterized in that, The slag interceptor includes a first slag interceptor with a semi-circular vertical cross-section, or the slag interceptor includes a second slag interceptor with a crescent-shaped vertical cross-section. The horizontal cross-sectional diameter of the primary slag-blocking and water-repellent layer on the first slag-blocking and water-repellent device is smaller than that of the secondary slag-blocking and water-repellent layer, with a diameter difference of 4-20cm. The horizontal cross-sectional diameter of the primary slag intercepting and dewatering layer on the second slag intercepting and dewatering device is the same as the horizontal cross-sectional diameter of the secondary slag intercepting and dewatering layer; Both the primary intercepting and dewatering layer and the secondary intercepting and dewatering layer include multiple annular segment bars spaced apart inside and outside, and multiple straight segment bars evenly distributed circumferentially along the annular segment bars. The gap between the straight and annular sections of the grid bars on the primary intercepting and drainage layer is greater than the gap between the straight and annular sections of the grid bars on the secondary intercepting and drainage layer. Each set of the aforementioned slag interceptor and drainer is fixedly connected to the top of the purification reactor via an installation component.

6. A method for treating rural sewage, implemented using the rural sewage denitrification and phosphorus removal system described in claim 1, characterized in that, It includes a variety of different operating modes to adapt to scenarios with varying raw water quality, water volume, and high and low loads; The operating modes include: M1, When the raw water in the lifting device does not require treatment, the rural sewage in the lifting device flows directly into the collection device. When the raw water in the M2 lifting device only requires denitrification or phosphorus removal, it undergoes biological denitrification or chemical phosphorus removal purification treatment through one of the purification reactor units. Meanwhile, in M2 mode, the following are included: M21, when the DO concentration of the effluent from the lifting device exceeds the empirical allowable concentration, and the SS concentration of the effluent from the lifting device does not exceed the empirical allowable concentration, the effluent from the lifting device enters the purification reactor unit from bottom to top. M22, when the SS concentration in the effluent of the lifting device exceeds the empirical allowable concentration, and the DO concentration in the effluent of the lifting device does not exceed the empirical allowable concentration, the effluent of the lifting device enters the purification reactor unit from top to bottom. When the raw water in the M3 lifting device only requires denitrification or phosphorus removal, it undergoes biological denitrification or chemical phosphorus removal purification treatment through another purification reactor unit in the M2 mode. In M3 mode, the following are also included: M31, when the DO concentration of the effluent from the lifting device exceeds the empirical allowable concentration, and the SS concentration of the effluent from the lifting device does not exceed the empirical allowable concentration, the effluent from the lifting device enters the purification reactor unit from bottom to top. M32, when the SS concentration in the effluent of the lifting device exceeds the empirical allowable concentration, and the DO concentration in the effluent of the lifting device does not exceed the empirical allowable concentration, the effluent of the lifting device enters the purification reactor unit from top to bottom. When the total nitrogen and total phosphorus levels in the raw water of M4 and the lifting device do not meet the expected water quality requirements, the raw water is subjected to biological denitrification and chemical phosphorus removal purification treatment through two purification reactor units. Meanwhile, in M4 mode, when the DO concentration in the effluent from the booster exceeds the empirically permissible concentration, but the SS concentration in the effluent from the booster does not exceed the empirically permissible concentration, the following two modes are used for treatment: M41, the water from the lifting device enters the first-stage purification reactor unit from bottom to top, and the water from the first-stage purification reactor unit enters the second-stage purification reactor unit from top to bottom, and after treatment, flows into the collection device. M42, the water from the lifting device enters the first-stage purification reactor unit from bottom to top, and the water from the first-stage purification reactor unit enters the second-stage purification reactor unit from bottom to top, and after treatment, flows into the collection device. Meanwhile, in M4 mode, when the SS concentration in the effluent from the booster exceeds the empirically permissible concentration, but the DO concentration in the effluent from the booster does not exceed the empirically permissible concentration, the following two modes are used for treatment: M43, the water from the lifting device enters the first-stage purification reactor unit from top to bottom, and the water from the first-stage purification reactor unit enters the second-stage purification reactor unit from bottom to top, and after treatment, flows into the collection device. M44, the effluent from the lifting device enters the first-stage purification reactor unit from top to bottom, and the effluent from the first-stage purification reactor unit enters the second-stage purification reactor unit from top to bottom, and after treatment, flows into the collection device.

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