Rural sewage nitrogen and phosphorus removal system and water treatment method

Abstract

The invention relates to a rural sewage nitrogen and phosphorus removal system and a water treatment method. The rural sewage nitrogen and phosphorus removal system comprises a lifting device, a purification device, a liquid collection device, a backwashing waste liquid device, a gas source flushing device, a serial pipeline device and a water distribution device, the purification reactor unit is respectively provided with a biological nitrogen removal packed bed and a chemical phosphorus removal packed bed, and the liquid collection 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 for uniformly distributing bottom inlet and outlet water and a slag intercepting and water distributing assembly for intercepting and uniformly distributing slag on top inlet and outlet water; the slag intercepting and water distributing assembly comprises a top uniform flow water distributor and a slag intercepting steam trap located above the top uniform flow water distributor. According to the invention, nitrogen and / or phosphorus can be flexibly and effectively removed according to the generation characteristics of rural sewage, the raw water quality of the sewage to be treated and the water volume high-low load variable scene, and the reinforced removal requirements of main pollutants such as carbon, nitrogen and phosphorus in the sewage in rural areas are met.

Description

Technical Field

[0001] The present application relates to the field of water treatment technology, and in particular to a rural sewage denitrification and dephosphorization system and a water treatment method. Background Art

[0002] In the existing centralized treatment process of agricultural and domestic sewage, conventionally only traditional A 2 O or its deformation process, the enhanced phosphorus and nitrogen removal relies on the configuration and addition of liquid reagents, and it is difficult to enhance the removal of major pollutants such as carbon, nitrogen and phosphorus. The nitrogen removal effect is often poor or the phosphorus removal effect is poor, or both are poor. There is no effective front-end tail water or anti-fouling and clogging layer before the filtration unit, and the graded slag cutting device measures, and the water distribution and drug distribution method is inappropriate, resulting in turbulent and uneven distribution. Especially for the buried drug addition and mixed reaction method, it is difficult to carry out intuitive inspection and observation and facilitate switching operations, and it is also difficult to adapt to the high and low load scenarios of the raw water quality and water volume of the treated water, or it is difficult to meet the flexible requirements of the combined control and switching of the working condition units for different water quality targets of the tail water.

[0003] In addition, the additional agents for nitrogen removal and phosphorus removal are purchased in solid form, dissolved in liquid form on site, or directly purchased in liquid form. Due to the remoteness of agricultural pollution sites or inconvenient transportation, the water source for diluting solid agents is limited, the mixing equipment for dissolving agents in tanks is insufficient, or the transportation and unloading of agents is inconvenient or there is no agent storage room, there are many limitations. The addition of agents also poses the risk of secondary pollution such as direct contact with personnel or environmental leakage. Agricultural pollution inspections are mostly intermittent, such as only once a day or only once a week. Due to insufficient inspection attention or untimely frequency, once the agents are exhausted and there is a shortage of drugs, it will directly affect and reduce the nitrogen removal and phosphorus removal purification effect of the agricultural pollution system, making it difficult for the tail water nitrogen and phosphorus to meet the expected emission index limit requirements, which may cause the receiving water body, especially closed rivers and semi-closed rivers, to exceed the pollution standard.

[0004] Agricultural sewage is often mixed with floating debris and slag, and the lack of effective slag interception, drainage and uniform water 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 sewage denitrification and phosphorus removal system and water treatment method, which is suitable for the daily treatment of agricultural sewage with a scale of 200m 3 / d or less, and can meet the needs of enhanced removal of major pollutants such as carbon, nitrogen and phosphorus in sewage, while achieving slag interception and drainage of agricultural sewage and improvement of uniform water inlet flow.

[0006] In order to achieve the above-mentioned object, 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 collecting device, a waste liquid backwashing device, an air source flushing device, a series pipe 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, and the purification device includes two purification reactor units, which are used to perform biological denitrification and chemical phosphorus removal purification treatments on the raw water respectively;

[0008] The purification reactor units are respectively provided with biological denitrification packing beds and chemical dephosphorization packing beds, the liquid collecting 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 pipes, the backwash waste liquid device is used to receive the backwash waste water generated by backwashing, and the series pipe device is arranged between different devices and two purification reactor units for branching and transporting rural sewage;

[0009] The water distribution device is arranged on the purification device, and includes a bottom uniform flow water distributor for uniformly distributing the inlet and outlet water at the bottom, and a slag cutting and water distribution component for cutting and uniformly distributing the inlet and outlet water at the top;

[0010] The slag cutting and water distribution assembly comprises a top uniform flow water distributor and a slag cutting drain located above the top uniform flow water distributor.

[0011] In an optional embodiment, the purification reactor unit is an underground module unit or an above-ground module unit, including a purification reactor made of corrosion-resistant material, and two of the purification reactors are respectively provided with fixed bed filler layers for biological denitrification or chemical phosphorus removal;

[0012] The fixed bed packing layer includes a dephosphorization packing bed and a denitrification packing bed, both of which are slow-release packings and have filtering functions. With respect to the flow direction of rural sewage, the dephosphorization packing bed and the denitrification packing bed are connected in series in a front or inverted manner.

[0013] The dephosphorization filler bed is filled with iron-based, iron-carbon-based and iron-calcium-based fillers with positive trivalent metal ions and composite dephosphorization, or a certain proportion of carbon fiber, graphene fiber or Cucurbitaceae plant fiber bundle is added therein as a bed strengthening base material;

[0014] The denitrification filler bed is filled with autotrophic or heterotrophic driven fillers that can provide good denitrification reaction electron donors and composite denitrification, or a certain proportion of carbon fiber or graphene fiber or Cucurbitaceae fiber bundles is added therein as one or more of the implantation base strengthening materials.

[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 uniform flow water distributor and the slag cutting water distribution assembly are respectively provided in the internal gaps;

[0016] An upper water inlet pipe and a lower water inlet pipe are respectively arranged inside the two purification reactors, and an upper water outlet pipe and a lower water outlet pipe are respectively connected to the two purification reactors;

[0017] Different water inlet pipes and water outlet pipes are respectively provided with control valves located outside the purification reactor;

[0018] The upper water inlet pipe member and the upper water outlet pipe member, as well as the lower water inlet pipe member and the lower water outlet pipe member are respectively arranged on two sides of the purification reactor in an opposite manner.

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

[0020] The upper water inlet pipe extends above the slag cut-off steam trap, and the extended end is retained in the central part of the slag cut-off steam trap;

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

[0022] The connection point of the upper water outlet pipe member on the purification reactor is located above the slag cut-off steam trap.

[0023] In an optional embodiment, the bottom uniform flow water distributor and the top uniform flow water distributor are respectively made of transparent PVC material, both of which are three-dimensional flat structures and have a transverse cross-section that is the same as the transverse cross-section of the purification reactor;

[0024] The bottom uniform flow water distributor and the top uniform flow water distributor respectively include a water outlet disc and a water inlet disc, and the water inlet disc and the water outlet disc are both provided with a plurality of water holes arranged in an annular manner, the number of water holes arranged on the water outlet disc is greater than the number of water holes arranged on the water inlet disc, and a hollow water distribution cavity is provided between the water inlet disc and the water outlet disc;

[0025] The raw water enters the uniform flow water distributor from bottom to top or from top to bottom and flows into the purification filler through the water holes.

[0026] In an optional embodiment, the slag cut-off steam trap is vertically opposite to the top uniform flow water distributor, and a gap of 5-10 cm is left between the bottom of the slag cut-off steam trap and the top uniform flow water distributor;

[0027] The slag cut-off drain device is a double-layer filter screen structure that is bent and concave inward, including a primary slag cut-off drain layer located at the upper part and a secondary slag cut-off drain layer located at the lower part;

[0028] The first-level slag cutting hydrophobic layer and the second-level slag cutting hydrophobic layer are stacked up and down and include a hollow hydrophobic cavity located therebetween.

[0029] In an optional embodiment, the slag cut-off steam trap includes a first slag cut-off steam trap having a semicircular ring shape in vertical cross section, or the slag cut-off steam trap includes a second slag cut-off steam trap having a crescent shape in vertical cross section;

[0030] The horizontal cross-sectional diameter of the first-stage slag cut-off drain layer on the first slag cut-off drain device is smaller than the horizontal cross-sectional diameter of the second-stage slag cut-off drain layer, and the diameter difference is 4-20 cm;

[0031] The horizontal cross-sectional diameter of the first-stage slag cut-off drain layer on the second slag cut-off drain device is the same as the horizontal cross-sectional diameter of the second-stage slag cut-off drain layer;

[0032] The first-level slag cut-off water-repellent layer and the second-level slag cut-off water-repellent layer both include a plurality of annular segment bars spaced inside and outside and a plurality of straight segment bars spaced evenly around the annular segment bars;

[0033] The bar gap formed by the straight bar segments and the annular bar segments on the first-level slag cutting water-repellent layer is larger than the bar gap formed by the straight bar segments and the annular bar segments on the second-level slag cutting water-repellent layer;

[0034] A single set of the slag cut-off drain is fixedly connected to the top of the purification reactor via a mounting member.

[0035] In an optional embodiment, the slag cut-off steam trap includes multiple sets arranged above the top uniform flow water distributor, and the multiple sets of the slag cut-off steam trap are evenly and symmetrically spaced around the top uniform flow water distributor.

[0036] In an optional embodiment, 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 collecting device includes a secondary detection component, the backwash waste liquid device includes a backwash waste liquid control valve, a short-circuit line and a short-circuit line control valve are arranged between the lifting device and the liquid collecting device, and the control system is electrically connected to the electronic control equipment and control valves in different devices, as well as to the purification device and the control valve in the series line device.

[0037] In a second aspect, 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 aforementioned embodiment, and includes a plurality of different operation modes to adapt to the high and low load variable scenarios of the raw water quality and water volume of the water to be treated;

[0038] The operating modes include:

[0039] M1, when the raw water in the lifting device does not need to be treated, the rural sewage in the lifting device flows directly into the liquid collecting device by gravity;

[0040] M2, when the raw water denitrification demand or phosphorus removal demand in the lifting device only includes its single enhanced water quality improvement demand, the raw water is purified by biological denitrification or chemical phosphorus removal through one of the purification reactor units;

[0041] Also in M2 mode, including:

[0042] M21, when the dissolved oxygen (DO) in the outflow of the lifting device exceeds the empirical allowable content (such as when the DO allowable content value is set to 3.5 mg / L), in order to prevent the upper free fall of the self-purification reactor unit from further falling and enriching the oxygen, under the condition that the suspended solids (SS) in the outflow of the lifting device does not exceed the empirical allowable concentration (such as when the SS allowable concentration value is set to 40 mg / L), the outflow of the lifting device enters the purification reactor unit from bottom to top;

[0043] M22, when the SS outflow from the lifting device exceeds the empirical allowable concentration (such as when the SS allowable concentration value is set to 40 mg / L), under the condition that the DO outflow from the lifting device does not exceed the empirical allowable concentration (such as when the DO allowable content value is set to 3.5 mg / L), in order to prevent the turbidity from entering the bottom of the purification reactor unit and being difficult to be removed from the packing by backwashing, and the SS turbidity can still be intercepted by the upper part of the packing even if it enters the upper part of the purification reactor unit, and can be efficiently removed from the packing by subsequent backwashing, the effluent of the lifting device enters the purification reactor unit from top to bottom;

[0044] M3, when the raw water denitrification demand or phosphorus removal demand in the lifting device only includes its single enhanced water quality improvement demand, the raw water is purified by biological denitrification or chemical phosphorus removal through another purification reactor unit in the M2 mode;

[0045] Also in M3 mode, including:

[0046] M31, when the DO of the outflow from the lifting device exceeds the empirical allowable content (such as when the DO allowable content value is set to 3.5 mg / L), in order to prevent the upper free fall of the self-purification reactor unit from further falling water and enriching oxygen, under the condition that the outflow SS of the lifting device does not exceed the empirical allowable concentration (such as when the SS allowable concentration value is set to 40 mg / L), the effluent of the lifting device enters the purification reactor unit from bottom to top;

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

[0048] M4, when the total nitrogen and total phosphorus indicators of the raw water in the lifting device cannot meet the expected water quality, the raw water is purified by biological denitrification and chemical dephosphorization through two purification reactor units at the same time;

[0049] At the same time, in the M4 mode, when the DO of the outflow from the lifting device exceeds the empirical allowable content (such as when the DO allowable content value is set to 3.5 mg / L), in order to prevent the upper free fall of the self-purification reactor unit from further falling and enriching water, under the condition that the outflow SS of the lifting device does not exceed the empirical allowable concentration (such as when the SS allowable concentration value is set to 40 mg / L), the following two modes are used for processing:

[0050] M41, the effluent of the lifting device enters the first-stage purification reactor unit from bottom to top, and the effluent of the first-stage purification reactor unit enters the second-stage purification reactor unit from top to bottom, and flows into the liquid collecting device after being treated;

[0051] M42, the effluent of the lifting device enters the first-stage purification reactor unit from bottom to top, and the effluent of the first-stage purification reactor unit enters the second-stage purification reactor unit from bottom to top, and flows into the liquid collecting device after being treated;

[0052] At the same time, in the M4 mode, when the SS outflow from the lifting device exceeds the empirical allowable concentration (such as when the SS allowable concentration value is set to 40 mg / L), under the condition that the DO outflow from the lifting device does not exceed the empirical allowable concentration (such as when the DO allowable content value is set to 3.5 mg / L), in order to prevent the contaminants from entering the bottom of the purification reactor unit and being difficult to remove from the packing by backwashing, the SS contaminants can still be intercepted by the upper part of the packing even if they enter the upper part of the purification reactor unit, and can be efficiently removed from the packing by subsequent backwashing, and are processed through the following two modes:

[0053] M43, the effluent of the lifting device enters the first-stage purification reactor unit from top to bottom, and the effluent of the first-stage purification reactor unit enters the second-stage purification reactor unit from bottom to top, and flows into the liquid collecting device after being treated;

[0054] M44, the effluent of the lifting device enters the first-stage purification reactor unit from top to bottom, and the effluent of the first-stage purification reactor unit enters the second-stage purification reactor unit from top to bottom, and flows into the liquid collecting device after being treated.

[0055] The rural sewage denitrification and phosphorus removal system and water treatment method of the present invention, wherein organic pollutants are further consumed as endogenous denitrification electron donors, suspended COD and suspended solids are removed by filtering and intercepting through a packed bed, solid floating garbage is intercepted and collected by a grid, and the goal of purifying tail water quality can be achieved by a full-chain system for coordinated removal of multiple pollutants such as 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, SS removal concentration exceeding 20 mg / L for nitrogen, phosphorus and suspended solids.

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

[0057] At the same time, the water treatment method of the present invention can perform flexible and effective denitrification and / or dephosphorization treatment according to the characteristics of rural sewage generation, the raw water quality of the sewage to be treated, and the variable water load scenarios of high and low water volume, so as to meet the needs of enhanced removal of major pollutants such as carbon, nitrogen, and phosphorus in sewage in rural areas.

[0058] Other features and advantages of the present application will be described in detail in the subsequent detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

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

[0061] Figure 2 It is a schematic diagram of the structure of the purification device;

[0062] Figure 3 It is a schematic diagram of the structure of the top uniform flow water distributor and the bottom uniform flow water distributor;

[0063] Figure 4The schematic diagrams are the structural diagrams of two different forms of top slag cutting and water distribution components;

[0064] Figure 5 The schematic diagrams are the structural diagrams of two different types of slag cut-off steam traps;

[0065] Figure 6 It is a structural schematic diagram of the installation parts of the slag cut-off steam trap;

[0066] Figure 7 It is a schematic diagram of different slag-cutting drain layers of the slag-cutting drain and the plane structure after assembly;

[0067] Figure 8 It is a schematic diagram of the planar structure of multiple slag cut-off steam traps on the top of the reactor;

[0068] Fig. 9 It is a schematic diagram of the flow forms in different modes in the water treatment method;

[0069] Fig.10 Schematic diagram of the removal efficiency of phosphorus removal for agricultural pollution alone;

[0070] Fig.11 Schematic diagram of the removal efficiency of nitrogen removal for agricultural pollution alone.

[0071] icon:

[0072] 1-lifting device; 11-unit to be purified; 12-lifting pump;

[0073] 13-lifting water delivery pipeline components; 131-water delivery main pipeline; 132-delivery branch pipeline; 132a-lifting liquid check valve; 132b-lifting liquid flow meter; 133-return liquid reduction pipeline; 133a-lifting circuit control valve;

[0074] 14-First level detection component;

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

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

[0077] 23-A type component outlet pipeline; 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 purification packed bed assembly; 31-B type purification reactor;

[0079] 32-B type component water inlet pipeline; 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 pipeline; 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 collecting device; 41-liquid collecting 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-gas source flushing device; 61-gas source equipment; 62-gas flushing conveying pipe fittings; 62a-gas source control valve; 62b-gas flushing check valve;

[0084] 7-series piping device; 70-short-circuit flow and drainage pipe fittings; 70a-short-circuit flow and drainage control valve; 71-liquid lifting and gas flushing pipe fittings; 72-liquid lifting and gas flushing branch pipe fittings; 72a-liquid lifting and gas flushing branch control valve; 73-liquid outlet branch pipe fittings; 74-liquid outlet collection pipe fittings; 74a-liquid outlet collection control valve; 75-purification and drainage pipe fittings; 75a-purification and drainage control valve;

[0085] 8-water distribution device; 80-top uniform flow water distributor; 81-bottom uniform flow water distributor;

[0086] 82-slag cut-off drain; 82a-first slag cut-off drain; 82b-second slag cut-off drain; 821-first slag cut-off drain layer; 821a-first straight section grid bar; 821b-first ring section grid bar; 821c-first installation center hole; 822-second slag cut-off drain layer; 822a-second straight section grid bar; 822b-second ring section grid bar; 822c-second installation center hole; 83-water hole;

[0087] 9-mounting part; 91-lateral bottom rod portion; 92-vertical round rod portion; 93-internal thread nut. DETAILED DESCRIPTION

[0088] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, rather than all of the embodiments. The components of the embodiments of the present application described and shown in the drawings here can be arranged and designed in various different configurations.

[0089] In the description of this application, it should be noted that the terms "inside", "outside", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the application is usually placed when in use, which is only for the convenience of describing this application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0090] In the description of this application, it should also be noted that, unless otherwise clearly specified and limited, the terms "disposed" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0091] The rural sewage denitrification and phosphorus removal system and water treatment method in the present application are mainly used for treating rural sewage (i.e., agricultural sewage). By setting up two packing beds with different functional forms, the agricultural sewage can be subjected to biological denitrification or chemical phosphorus removal treatment alone. At the same time, the agricultural sewage can be subjected to successive biological denitrification or chemical phosphorus removal treatment by passing through two packing beds with different functions in sequence.

[0092] Combined with the necessary slag interception and water distribution structure, the floating debris slag can be effectively intercepted before the agricultural sewage enters the packing bed from the top, and the water is evenly distributed through the water distributor after the slag is intercepted. The agricultural sewage can also obtain the water distribution effect of uniform water flow when entering the packing bed from the bottom.

[0093] The rural sewage denitrification and phosphorus removal system of the present invention can realize water inlet and outlet in various modes, which can meet the requirements of the raw water quality and water volume of the treated water in actual application, with variable loads.

[0094] See also Figure 1 The rural sewage denitrification and phosphorus removal system of the present invention comprises: a lifting device 1, a purification device, a liquid collecting device 4, a waste liquid backwashing device 5, an air source flushing device 6, a series pipe 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, which includes two purification reactor units for performing biological denitrification and chemical phosphorus removal purification treatments on the raw water respectively;

[0096] The purification reactor units are respectively provided with biological denitrification packing beds and chemical dephosphorization packing beds, the liquid collecting device is used to receive purified water, the air source flushing device 6 can cooperate with the lifting device 1 to backwash the purification device and the connecting pipes, the backwashing waste liquid device 5 is used to receive the backwashing waste water generated by backwashing, and the series pipe device 7 is arranged between different devices and two purification reactor units for branching and transporting rural sewage;

[0097] The water distribution device 8 is arranged on the purification device, and includes a bottom uniform flow water distributor 81 for uniformly distributing the inlet and outlet water at the bottom, and a slag-cutting water distribution component for cutting and uniformly distributing the inlet and outlet water at the top;

[0098] The slag cutting and water distribution assembly includes a top uniform flow water distributor 80 and a slag cutting drain 82 located above the top uniform flow water distributor 80 .

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

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

[0101] The lifting pump 12 is used to pressure-pump the liquid in the unit to be purified 11 to the purification device. The lifting water delivery pipeline component 13 includes a water delivery main pipeline 131 connected to the lifting pump 12, a delivery branch pipeline 132, and a liquid return reduction pipeline 133. A liquid lifting check valve 132a and a lifting liquid flow meter 132b are arranged on the delivery branch pipeline 132. The liquid lifting check valve 132a is used as a one-way fluid control to prevent the backflow of the delivered fluid from causing damage to the lifting pump 12 by the heavy hammer. The lifting liquid flow meter 132b is used to measure the purified sewage delivery flow rate flowing through the delivery branch pipeline 132. A lifting loop control valve 133a is arranged on the liquid return reduction pipeline 133 to adjust the flow rate refluxed 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 delivered to the purification device to the expected flow range. The pipe nodes of the water delivery main pipeline 131, the delivery branch pipeline 132 and the liquid return reduction pipeline 133 are connected.

[0102] The primary detection component 14 can optionally be installed with a single parameter of suspended solids (SS) or dissolved oxygen (DO), or a dual parameter detection sensor probe and a digital display converter head for dynamically detecting the suspended solids SS concentration and / or DO value in the unit to be purified 11. On this basis, it can also be expanded to add a phosphate or nitrate real-time detection multi-instrument parameter module, so as to more real-time and accurately monitor and evaluate the biological denitrification removal effect and efficiency of nitrogen-containing pollutants, or the chemical dephosphorization removal effect and efficiency of phosphorus-containing pollutants.

[0103] The purification device comprises two purification reactor units, which are used for biological denitrification and chemical dephosphorization purification of raw water. The purification reactor units are respectively provided with biological denitrification filler beds and chemical dephosphorization filler beds.

[0104] In order to facilitate the explanation of the two purification reactor units of the purification device in the present application, the explanation is 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 unit is an underground module unit or a ground-mounted module unit, which has the advantages of short installation period, wide adaptability, multiple scheduling modes, fast performance, good pollution removal effect and long maintenance period.

[0105] Specifically, see Figure 2 The A-type purification packed bed assembly 2 includes an A-type purification reactor 21 of the packed bed body, an A-type assembly water inlet pipeline 22, and an A-type assembly water outlet pipeline 23. The A-type purification reactor 21 is a packing bed body purification unit, and a corrosion-resistant material reactor with a cylindrical or rectangular structure can be used. The A-type purification reactor 21 is provided with an A-type fixed bed packing layer 24 for either biological denitrification or chemical phosphorus removal.

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

[0107] The bottom uniform flow water distributor 81 and the slag cutting and water distribution assembly are respectively arranged in the internal gap. Through this arrangement, sufficient space can be provided for the inlet and outlet of water in the reactor to meet the needs of slag cutting and uniform water distribution.

[0108] The A-type component water inlet pipeline 22 includes an A-type lower water inlet pipe fitting 221, which extends below the bottom uniform flow water distributor 81, and the extended end is retained in the center of the bottom uniform flow water distributor 81. The A-type lower water inlet pipe fitting 221 is provided with an A-type lower water inlet control valve 221a, and the valve is arranged on the outside of the tank body of the A-type purification reactor 21 to facilitate the operation of the valve during operation and maintenance.

[0109] The A-type component water inlet pipeline 22 also includes an A-type upper water inlet pipe 222, which extends above the slag cut-off trap 82, and the extended end is placed in the center of the slag cut-off trap 82. Through this arrangement, the top water inlet can first be passed to the slag cut-off trap 82, so that the water inlet is effectively cut off, and then enters the top uniform flow water distributor 80 located below the slag cut-off trap 82, and enters the A-type fixed bed packing layer 24 after uniform water distribution. The A-type upper water inlet pipe 222 is provided with an A-type upper water inlet control valve 222a, which is arranged outside the tank of the A-type purification reactor 21, so as to facilitate the operation of the valve in operation and maintenance.

[0110] The A-type component outlet pipe 23 is connected to the A-type purification reactor 21, and includes an A-type lower outlet pipe fitting 231 and an A-type upper outlet pipe fitting 232. The connection point of the A-type lower outlet 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 water distributor 81, and the purified sewage can be discharged at the bottom. The A-type lower outlet pipe fitting 231 is provided with an A-type lower outlet control valve 231a, which is arranged outside the tank body of the A-type purification reactor 21 to facilitate the operation and maintenance of the valve.

[0111] The connection point of the A-type upper water outlet pipe 232 on the A-type purification reactor 21 is located above the slag cut-off drain 82, and is provided with an A-type upper water outlet control valve 232a, which is arranged outside the tank body of the A-type purification reactor 21 to facilitate operation and maintenance of the valve.

[0112] The A-type component water inlet pipeline 22 and the A-type component water outlet pipeline 23 are respectively arranged on two sides of the A-type purification reactor 21.

[0113] Through the above-mentioned arrangement, a relatively stable water flow of inflow from bottom to top or inflow from top to bottom can be formed, thereby enabling purification treatment in water treatment methods of different modes.

[0114] Correspondingly, the B-type purification packed bed assembly 3 includes a B-type purification reactor 31 of the packed bed main body, a B-type assembly water inlet pipe 32, and a B-type assembly water outlet pipe 33. The B-type purification reactor 31 is a packing bed main body purification unit, and can adopt a corrosion-resistant material reactor with a cylindrical or rectangular structure. A B-type fixed bed packing layer 34 for either biological denitrification or chemical phosphorus removal is arranged in the B-type purification reactor 31.

[0115] A certain height 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 water inlet and outlet of the reactor.

[0116] The bottom uniform flow water distributor 81 and the slag cutting and water distribution assembly are respectively arranged in the internal gap. Through this arrangement, sufficient space can be provided for the inlet and outlet of water in the reactor to meet the needs of slag cutting and uniform water distribution.

[0117] The B-type component water inlet pipeline 32 includes a B-type lower water inlet pipe fitting 321, which extends below the bottom uniform flow water distributor 81, and the extended end is retained in the center of the bottom uniform flow water distributor 81. The B-type lower water inlet pipe fitting 321 is provided with a B-type lower water inlet control valve 321a, and the valve is arranged on the outside of the tank body of the B-type purification reactor 31 to facilitate the operation and maintenance of the valve.

[0118] The B-type component water inlet pipeline 32 also includes a B-type upper water inlet pipe 322, which extends above the slag cut-off trap 82, and the extended end is placed in the center of the slag cut-off trap 82. Through this arrangement, the top water inlet can first be passed to the slag cut-off trap 82, so that the water inlet is effectively cut off, and then enters the top uniform flow water distributor 80 located below the slag cut-off trap 82, and enters the B-type fixed bed packing layer 34 after uniform water distribution. The B-type upper water inlet pipe 322 is provided with a B-type upper water inlet control valve 322a, which is arranged outside the tank body of the B-type purification reactor 31, so as to facilitate the operation and maintenance of the valve.

[0119] The B-type component outlet pipe 33 is connected to the B-type purification reactor 31, and includes a B-type lower outlet pipe fitting 331 and a B-type upper outlet pipe fitting 332. The connection point of the B-type lower outlet 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 water distributor 81, and the purified sewage can be discharged at the bottom. The B-type lower outlet pipe fitting 331 is provided with a B-type lower outlet control valve 331a, which is arranged outside the tank body of the B-type purification reactor 31 to facilitate the operation and maintenance of the valve.

[0120] The connection point of the B-type upper water outlet pipe 332 on the B-type purification reactor 31 is located above the slag cut-off drain 82, and a B-type upper water outlet control valve 332a is provided. The valve is arranged outside the tank body of the B-type purification reactor 31 to facilitate operation and maintenance of the valve.

[0121] The B-type component water inlet pipeline 32 and the B-type component water outlet pipeline 33 are respectively arranged on two sides of the B-type purification reactor 31.

[0122] In the two purification reactor units arranged relatively to each other, when and only when the A-type fixed bed packing layer 24 chooses to install biological denitrification filler, the B-type fixed bed packing layer 34 chooses chemical dephosphorization filler with differentiated functions; when and only when the A-type fixed bed packing layer 24 chooses to install chemical dephosphorization filler, the B-type fixed bed packing layer 34 chooses biological denitrification filler with differentiated functions.

[0123] That is to say, the dephosphorization packing bed and the denitrification packing bed provided in the A-type fixed bed packing layer 24 or the B-type fixed bed packing layer 34 in the present application can be mutually connected in a front or inverted series mode. Further, the front or inverted series mode 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 having effective flexibility.

[0124] The biological denitrification filler layer can be an autotrophic or heterotrophic driven slow-release filler that can provide good denitrification reaction electron donors and composite denitrification and filtration functions. The chemical dephosphorization filler layer can be an iron-based, iron-carbon-based, iron-calcium-based slow-release filler with positive trivalent metal ions and composite dephosphorization and filtration functions. Furthermore, a certain proportion of carbon fiber or graphene fiber or Cucurbitaceae fiber bundles can be added to the biological denitrification filler layer and the chemical dephosphorization filler layer as a base material for implantation.

[0125] The packing volume of the type A fixed bed packing layer 24 and the type B fixed bed packing layer 34 is appropriate to ensure that the design hydraulic retention time of the type A purification reactor 21 or the type B purification reactor 31 is 25 to 120 minutes, so that the packing has sufficient and effective contact reaction and purification time with pollutants such as nitrogen and phosphorus in the water. The biological denitrification packing bed and the chemical dephosphorization packing bed are both slow-release packing beds with filtering functions. They are gradually consumed as they are purified. Generally, the final consumption cycle can reach 9 to 12 months. Therefore, it is only necessary to regularly replenish the packing during the inspection every 3 to 6 months, or according to the evaluation of the purification and removal effect, if it is lower than expected, the enhanced feeding can be started, especially before the winter in November, to stabilize the operation and purification effect under unfavorable water or environmental climate conditions such as winter. Therefore, it has the characteristics of a long replenishment cycle, which greatly reduces the difficulty of maintenance for on-site operation and maintenance personnel and the work intensity of a single replenishment.

[0126] See also Figure 3 From the perspective of facilitating water distribution and draining slag, the bottom uniform flow water distributor 81 and the top uniform flow water distributor 80 are respectively made of transparent PVC material, both of which are three-dimensional flat structures. Preferably, a hollow water distribution cavity is respectively provided inside the bottom uniform flow water distributor 81 and the top uniform flow water distributor 80, and the hollow water distribution cavity mainly plays a buffering effect. After the incoming water passes into the hollow water distribution cavity, it is buffered and then flows out from the evenly distributed water holes 83.

[0127] The use of transparent materials creates conditions for visual inspection and observation of the packing layer. In order to ensure an effective water distribution area and to make the incoming water more evenly dispersed at the top or bottom of the reactor, the transverse cross-sections of the bottom uniform flow water distributor 81 and the top uniform flow water distributor 80 are the same as the transverse cross-section shape of the purification reactor.

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

[0129] In order to effectively install the uniform flow water distributor, the surface cross-sectional areas of the bottom uniform flow water distributor 81 and the top uniform flow water distributor 80 are slightly smaller than the internal cross-sectional areas of the type A purification reactor 21 and the type B purification reactor 31 .

[0130] The bottom uniform flow water distributor 81 and the top uniform flow water distributor 80 respectively include a water outlet disk and a water inlet disk, except that the water outlet disk of the bottom uniform flow water distributor 81 is arranged upward, while the water outlet disk of the top uniform flow water distributor 80 is arranged downward.

[0131] A plurality of circularly arranged water holes 83 are provided on the water inlet disk and the water outlet disk. The number of water holes 83 on the water outlet disk is greater than the number of water holes 83 on the water inlet disk, and the aperture of the water holes 83 on the water inlet disk is greater than the aperture of the water holes 83 on the water inlet disk, thereby reducing the resistance of agricultural sewage entering the hollow water distribution cavity.

[0132] The water distributor in the present application specifically forms two effects through the water inlet disk and the water outlet disk. Firstly, it can form a certain filtering effect through the double-layer setting of the water inlet disk and the water outlet disk. Secondly, the cavity between the water inlet disk and the water outlet disk constitutes a hollow water distribution cavity. The agricultural sewage enters the hollow water distribution cavity through the water holes 83 on the water inlet disk and is then discharged, forming a certain buffering effect, which can reduce the impact of water quality and water volume fluctuations of agricultural sewage on stable water inlet.

[0133] The raw water enters the hollow water distribution cavity of the uniform flow water distributor from bottom to top or from top to bottom and flows into the purification filler through the water holes 83 .

[0134] Of course, based on the setting of the hydrophobic slag interceptor, when the bottom water flows in, the agricultural sewage only needs to enter from the bottom of the fixed bed packing layer, and enter the hollow water distribution cavity of the bottom uniform flow water distributor 81 through the water hole 83 on the water inlet disk surface located below the bottom uniform flow water distributor 81, and after water distribution, enter the fixed bed packing layer through the water hole 83 on the water outlet disk surface located above for purification.

[0135] When water flows in from the top, agricultural sewage first flows to the top of the drain interceptor, obtains physical interception and drainage, and then enters the hollow water distribution cavity of the top uniform flow water distributor 80 through the water hole 83 on the upper water inlet disk, and then flows into the purification filler through the water hole 83 on the lower water outlet disk to complete the interception and water distribution.

[0136] Based on the above-mentioned connection between slag cutting and water distribution when water flows over the top, the slag cutting drain 82 and the top uniform flow water distributor 80 are opposite to each other up and down, so that the agricultural sewage from the slag cutting can directly fall into the top uniform flow water distributor 80, achieving double buffering of stable upper water inflow.

[0137] A gap of 5-10 cm is left between the bottom of the slag cut-off steam trap 82 and the top uniform flow water distributor 80. The gap of this part can provide a certain falling space for the slag cut-off steam trap 82, so that the incoming water on the slag cut-off steam trap 82 can be evenly distributed using the gap of this part, and then the top incoming water flow can be fully dispersed, so as to ensure the uniformity of the top incoming water dispersion.

[0138] Combination Figure 4-Figure 8 From the perspectives of slag filtering and dispersed water drainage, the slag drain 82 is a double-layer filter screen structure that is bent inward and concave, including a primary slag drain layer 821 located at the upper part and a secondary slag drain layer 822 located at the lower part. The double-layer filter screen that is bent inward and concave can have a certain water collection effect, that is, double-layer filtration is performed through a curved surface strainer structure similar to that including grid bars.

[0139] The primary slag-cutting hydrophobic layer 821 and the secondary slag-cutting hydrophobic layer 822 are stacked up and down, and include a hollow hydrophobic cavity between the two. When water flows in from the top, the agricultural sewage flowing out from the upper water inlet pipe is first intercepted by the primary slag-cutting hydrophobic layer 821, and the larger floating debris is intercepted at the upper part of the primary slag-cutting hydrophobic layer 821. Then, the agricultural sewage after the initial slag-cutting enters the hollow hydrophobic cavity, which is used for drainage and also forms a certain buffer. The smaller floating debris is cut off for the second time by the secondary slag-cutting hydrophobic layer 822, so as to minimize the impurity content entering the fixed bed packing layer and extend the service life of the fixed bed packing layer.

[0140] In view of the inlet conditions of agricultural sewage with different contents of floating impurities, the slag intercepting drain 82 in the present invention includes two different structural forms, which can intercept the floating impurities respectively. The difference between the two different forms of slag intercepting drain 82 lies in the different areas of interception and drainage.

[0141] Specifically, the slag cut-off steam trap 82 includes a first slag cut-off steam trap 82a having a semicircular ring shape in vertical section, or the slag cut-off steam trap 82 includes a second slag cut-off steam trap 82b having a crescent shape in vertical section.

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

[0143] That is to say, there is no water grid or gap at the diameter difference position. After the agricultural sewage passes through the first-level slag-cutting hydrophobic layer 821 with a bowl-shaped structure, there is a certain diffusion buffer inside the hollow hydrophobic cavity, and then passes through the second-level slag-cutting hydrophobic layer 822. This setting method is suitable for agricultural sewage with less floating impurities, and is also conducive to the dredging of slag impurities.

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

[0145] After passing through the first-level slag cut-off hydrophobic layer 821 with a bowl-shaped structure, the agricultural sewage directly flows through the second-level slag cut-off hydrophobic layer 822 through the hollow hydrophobic cavity. This setting method is suitable for agricultural sewage with a large content of floating impurities, and can avoid the overall clogging of the slag cut-off hydrophobic device 82 by the slag cut-off impurities to a certain extent.

[0146] From the perspective of the drainage structure, no matter what kind of structure is used, the primary slag drainage layer 821 and the secondary slag drainage layer 822 on the slag drainage device 82 both include a plurality of annular segment bars spaced inside and outside and a plurality of straight segment bars spaced evenly around the annular segment bars;

[0147] The bar gap formed by the first-level straight-segment bars 821a and the first-level annular-segment bars 821b on the first-level slag-cutting hydrophobic layer 821 is larger than the bar gap formed by the second-level straight-segment bars 822a and the second-level annular-segment bars 822b on the second-level slag-cutting hydrophobic layer 822;

[0148] Thereby, the first-level slag-cutting hydrophobic layer 821 can intercept the first-level coarse-grained slag in the grid gap, and then the second-level slag-cutting hydrophobic layer 822 can intercept the second-level fine-grained slag in the grid gap, and it can also prevent water stagnation caused by poor flow in the first-level slag-cutting hydrophobic layer 821.

[0149] A single set of the slag cut-off steam trap 82 is connected and anchored on the top of the purification reactor through the mounting member 9, and the centers of the first slag cut-off steam trap 82a and the second slag cut-off steam trap 82b are respectively provided with a first mounting center hole 821c and a second mounting center hole 822c.

[0150] Specifically, the mounting member 9 includes a transverse bottom rod portion 91, a vertical round rod portion 92 and two pairs of internal thread nuts 93. The vertical round rod portion 92 includes two segments of threaded screws arranged at intervals. During the installation process, the vertical round rod portion 92 is passed through the first installation center hole 821c of the first slag cut-off drain 82a, or through the first installation center hole 821c of the second slag cut-off drain 82b, and the secondary slag cut-off drain layer 822 and the primary slag cut-off drain layer 821 are fixed to the vertical round rod portion 92 respectively through the two pairs of internal thread nuts 93.

[0151] This arrangement facilitates the assembly and disassembly of the primary slag cut-off hydrophobic layer 821 and the secondary slag cut-off hydrophobic layer 822 on the mounting member 9, facilitates operation and maintenance, and enables offline manual flushing to remove solid floating garbage such as slag attached to the primary slag cut-off hydrophobic layer 821 and the secondary slag cut-off hydrophobic layer 822.

[0152] The slag cut-off steam trap 82 in the present invention includes multiple sets arranged above the top uniform flow water distributor 80, and the multiple sets of slag cut-off steam traps 82 are evenly spaced and symmetrically distributed in the circumferential direction relative to the top uniform flow water distributor 80. Figure 8 Taking four sets of examples, agricultural sewage flows to the center of the reactor tank through the A-type upper water inlet pipe 222 or the B-type upper water inlet pipe 322, and then the pipeline is bent downward to distribute four branches, and the four branches extend to the top of the center of the slag drainer 82 respectively, through which slag drainage and uniform water distribution are carried out.

[0153] For other components of rural sewage denitrification and phosphorus removal system:

[0154] The liquid collecting device 4 includes a liquid collecting unit container 41 and a secondary detection component 42. The liquid collecting unit container 41 is used to receive the treated liquid after purification treatment from the A-type purification packing bed component 2 or the B-type purification packing bed component 3, or the liquid directly discharged by gravity from the unit to be purified 11, and discharge it to the subsequent unit. The secondary detection component 42 specifically installs a single-parameter detection sensor probe for suspended matter and a digital display converter head. On this basis, it can also be expanded to add a phosphate or nitrate real-time detection multi-instrument parameter module to implement dynamic detection of the suspended matter (SS) concentration in the liquid collecting unit container 41, or expand the synchronous monitoring of phosphate or nitrate concentration, so as to more accurately monitor and evaluate the biological denitrification removal effect and efficiency of nitrogen-containing pollutants, or the chemical dephosphorization removal effect and efficiency of phosphorus-containing pollutants in real time, and provide 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 includes a backwash waste liquid control valve 52a. The backwash waste liquid control valve 52a is arranged outside the tank body of the backwash waste liquid unit container 51 to facilitate the operation of the valve.

[0156] The gas source flushing device 6 includes a gas source device 61 and a gas flushing delivery pipe 62. The gas flushing delivery pipe 62 is provided with a gas source control valve 62a and a gas flushing check valve 62b. The gas flushing check valve 62b is used as a one-way fluid control to prevent the conveying liquid phase fluid from the conveying branch pipeline 132 from reversely flowing into the gas source device 61 and damaging it.

[0157] The serial piping device 7 includes a short-circuit flow pipe 70, a liquid-lifting gas flushing pipe 71, a liquid-lifting gas flushing branch pipe 72, a liquid outlet branch pipe 73, a liquid outlet collecting pipe 74, and a purified liquid discharge pipe 75, wherein: the short-circuit flow pipe 70 is a gravity self-flow pipe for the purified unit 11 to flow to the liquid receiving unit container 41; the liquid-lifting gas flushing pipe 71 is connected in series with the delivery branch pipe 132 and the gas flushing delivery pipe 62, and then connected to the A-type upper water inlet pipe 222 and the A-type lower water inlet pipe 221; the liquid-lifting gas flushing pipe 71 and the A-type upper water inlet pipe 2 22. The A-type lower water inlet pipe fitting 221 is connected in series and then merged into the liquid-lifting gas-flushing branch pipe fitting 72; the liquid outlet branch pipe fitting 73 is connected in series with the A-type lower water outlet pipe fitting 231, the A-type upper water outlet pipe fitting 232, the B-type lower water inlet pipe fitting 321, and the B-type upper water inlet pipe fitting 322, and then connected in series with the liquid-lifting gas-flushing branch pipe fitting 72 and then merged into the liquid outlet collecting pipe fitting 74; the liquid outlet collecting pipe fitting 74 is connected in series with the B-type lower water outlet pipe fitting 331 and the B-type upper water outlet pipe fitting 332, and then merged into the purification drainage pipe fitting 75, and then enters the liquid collecting unit container 41. The short-circuit flow control valve 70a, the liquid-lifting gas-rush branch control valve 72a, the liquid-outlet collecting control valve 74a and the purified liquid-draining pipe fitting 75 are respectively provided with a short-circuit flow control valve 70a, a liquid-lifting gas-rush branch control valve 72a, a liquid-outlet collecting control valve 74a and a purified liquid-draining control valve 75a.

[0158] The present 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 collecting device 4 includes a secondary detection component 42, the backwash waste liquid device 5 includes a backwash waste liquid control valve 52a, a short-circuit line and a short-circuit line control valve are arranged between the lifting device 1 and the liquid collecting device 4, and the control system is electrically connected to the electronic control equipment and control valves in different devices, as well as to the purification device and the control valve in the series line device 7.

[0159] Through the electrical connection between the control system and different control valves and electronic control equipment, automatic control can be achieved to meet intelligent operation, and at the same time, specific references can be provided for different modes of water treatment methods.

[0160] The present invention also provides a water treatment method, which is carried out according to the rural sewage denitrification and phosphorus removal system described above, including a plurality of different operation modes to adapt to the raw water quality and water volume of the treated water with high and low loads, see Fig. 9 , the A-type purification packing bed assembly 2 is used as the biological denitrification packing bed function, while the B-type purification packing bed assembly 3 is used as the chemical phosphorus removal packing bed function. The operation modes include:

[0161] In the M1 mode, when it is detected that the effluent from the lifting device 1 has met the expected water quality and there is no need to further enhance the water quality through nitrogen removal and phosphorus removal, the lifting device 1 directly flows into the liquid collecting device 4 by gravity, and the type A purification packed bed assembly 2 and the type B purification packed bed assembly 3 are both in an offline non-reactive condition.

[0162] In the M2 mode, when the primary detection component 14 detects that the raw water denitrification demand or phosphorus removal demand in the lifting device 1 only contains a 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 it is detected that one of the total nitrogen or total phosphorus indicators of the effluent from the lifting device 1 has met the expected water quality, and the denitrification demand or phosphorus removal demand only contains a single enhanced water quality improvement demand, such as the total nitrogen demand has been met and only the phosphorus removal water quality improvement demand is required; or the phosphorus removal demand has been met and only the ammonia removal water quality improvement demand is required, the type A purification packing bed assembly 2 participates in the reaction condition, while the type B purification packing bed assembly 3 is in an offline non-reaction condition.

[0164] In the M21 mode, when the secondary detection component 42 detects that the DO of the outflow of the lifting device 1 exceeds the empirically permissible content (such as when the DO permissible content value is set to 3.5 mg / L), in order to prevent the free fall from the upper part of the self-unit A-type purification packing bed component 2 to further drop and enrich the water with oxygen, under the condition that the secondary detection component 42 simultaneously detects that the outflow SS of the lifting device 1 does not exceed the empirically permissible concentration (such as when the SS permissible concentration value is set to 40 mg / L), the A-type purification packing bed component 2 of the water outlet of the lifting device 1 adopts an upward flow state, that is, a bottom-up mode is more suitable, and the lifting device 1 takes in water from the bottom of the A-type purification packing bed component 2, and the water reacts and exits from the top of the A-type purification packing bed component 2 and then flows into the liquid collecting device 4, that is, the flow of the A-type purification packing bed component 2 adopts a bottom-in and top-out method.

[0165] In the M22 mode, when the secondary detection component 42 detects that the SS outflow from the lifting device 1 exceeds the empirical allowable concentration (such as when the SS allowable concentration value is set to 40 mg / L), and the secondary detection component 42 detects that the DO outflow from the lifting device 1 does not exceed the empirical allowable concentration (such as when the DO allowable content value is set to 3.5 mg / L), in order to prevent the contaminants from entering the bottom of the A-type purification packing bed component 2 and being difficult to backwash out of the A-type purification packing bed component 2 system, even if the SS contaminants enter the A-type purification packing bed component 2, the SS contaminants are removed from the bottom of the A-type purification packing bed component 2. 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 performed from bottom to top in countercurrent with the incoming water. 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 is more suitable. The lifting device 1 takes in water from the top of the A-type purification packing bed assembly 2, and the water reacts from the bottom of the A-type purification packing bed assembly 2 and then flows into the liquid collecting device 4, that is, the flow of the A-type purification packing bed assembly 2 adopts a top-in and bottom-out mode.

[0166] In the M3 mode, when the raw water denitrification demand or phosphorus removal demand in the lifting device 1 only includes a single enhanced water quality improvement demand, the raw water is subjected to biological denitrification or chemical phosphorus removal purification treatment through another purification reactor unit in the M2 mode.

[0167] Specifically, in the M31 and M32 modes, when it is detected that one of the total nitrogen or total phosphorus indicators of the effluent from the lifting device 1 has met the expected water quality, and the denitrification demand or phosphorus removal demand only contains a single enhanced water quality improvement demand, such as the total nitrogen demand has been met and only the phosphorus removal water quality improvement demand is required; or the phosphorus removal demand has been met and only the ammonia removal water quality improvement demand is required, the B-type purification packing bed assembly 3 participates in the reaction condition, while the A-type purification packing bed assembly 2 is in an offline non-reaction condition.

[0168] In the M31 mode, when the secondary detection component 42 detects that the DO of the outflow of the lifting device 1 exceeds the empirically permissible content (such as when the DO permissible content value is set to 3.5 mg / L), in order to prevent the free fall from the upper part of the self-unit B-type purification packing bed component 3 to further drop water and enrich oxygen, under the condition that the secondary detection component 42 simultaneously detects that the outflow SS of the lifting device 1 does not exceed the empirically permissible concentration (such as when the SS permissible concentration value is set to 40 mg / L), the B-type purification packing bed component 3 of the water outlet of the lifting device 1 adopts an upward flow state, that is, the bottom-up mode is more suitable, the lifting device 1 takes in water from the bottom of the B-type purification packing bed component 3, and the water reacts and flows into the liquid collecting device 4 from the top of the B-type purification packing bed component 3, that is, the flow of the A-type purification packing bed component 2 adopts a bottom-in and top-out method.

[0169] In the M32 mode, when the secondary detection component 42 detects that the SS outflow of the lifting device 1 exceeds the empirical allowable concentration (such as when the SS allowable concentration value is set to 40 mg / L), and the secondary detection component 42 detects that the DO outflow of the lifting device 1 does not exceed the empirical allowable concentration (such as when the DO allowable content value is set to 3.5 mg / L), in order to prevent the contaminants from entering the bottom of the B-type purification packing bed component 3 and being difficult to backwash and clear out of the B-type purification packing bed component 3 system, even if the SS contaminants enter the B-type purification packing bed component 3, the SS contaminants are not removed from the B-type purification packing bed component 3. 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 through subsequent pulse backwashing performed from bottom to top in a countercurrent manner with the incoming water. 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 is more suitable. The lifting device 1 takes in water from the top of the B-type purification packing bed assembly 3, and the water reacts from the bottom of the B-type purification packing bed assembly 3 and then flows into the liquid collecting device 4, that is, the flow of the B-type purification packing bed assembly 3 adopts a top-in and bottom-out mode.

[0170] In M4 mode, when the total nitrogen and total phosphorus indicators of the raw water in the lifting device 1 cannot meet the expected water quality, the raw water is purified by biological denitrification and chemical dephosphorization through two purification reactor units at the same time;

[0171] At the same time, in the M4 mode, when the DO of the outflow from the lifting device 1 exceeds the empirical allowable content (such as when the DO allowable content value is set to 3.5 mg / L), in order to prevent the upper free fall of the self-purification reactor unit from further falling and enriching oxygen, under the condition that the outflow SS of the lifting device 1 does not exceed the empirical allowable concentration (such as when the SS allowable concentration value is set to 40 mg / L), the following two modes are used for processing:

[0172] Specifically, in the M41 and M42 modes, when the first-level detection component 14 detects that the total nitrogen and total phosphorus indicators of the outlet water of the lifting device 1 cannot meet the expected water quality, denitrification and phosphorus removal still need to be processed by the flow of type A purification packing bed component 2 and type B purification packing bed component 3 in order to strengthen the dual needs of water quality improvement, type A purification packing bed component 2 and type B purification packing bed component 3 both participate in the reaction conditions.

[0173] In the M41 mode, the lifting device 1 takes in water through the bottom of the A-type purification packing bed assembly 2, and after the water reacts from the top of the A-type purification packing bed assembly 2, it flows into the top of the B-type purification packing bed assembly 3, and after the water reacts from the bottom of the B-type purification packing bed assembly 3, it flows into the liquid collecting device 4, that is, the flow of the A-type purification packing bed assembly 2 and the B-type purification packing bed assembly 3 adopts the bottom-in and top-out method of the A-type purification packing bed assembly 2 and the top-in and bottom-out method of the B-type purification packing bed assembly 3.

[0174] In the M42 mode, the lifting device 1 takes in water through the bottom of the A-type purification packing bed assembly 2, and the water reacts from the top of the A-type purification packing bed assembly 2 and flows into the bottom of the B-type purification packing bed assembly 3, and the water reacts from the top of the B-type purification packing bed assembly 3 and flows into the liquid collecting device 4, that is, the flow of the A-type purification packing bed assembly 2 and the B-type purification packing bed assembly 3 adopts the bottom-in and top-out mode of the A-type purification packing bed assembly 2 and the bottom-in and top-out mode of the B-type purification packing bed assembly 3 respectively.

[0175] At the same time, in the M4 mode, when the outflow SS in the lifting device 1 exceeds the empirical allowable concentration (such as when the SS allowable concentration value is set to 40 mg / L), under the condition that the outflow DO in the lifting device 1 does not exceed the empirical allowable concentration (such as when the DO allowable content value is set to 3.5 mg / L), in order to prevent the contaminants from entering the bottom of the purification reactor unit and being difficult to be removed from the packing by backwashing, the SS contaminants can still be intercepted by the upper part of the packing even if they enter the upper part of the purification reactor unit, and can be efficiently removed from the packing by subsequent backwashing, and are processed through the following two modes:

[0176] Specifically, when the secondary detection component 42 detects that the SS outflow from the lifting device 1 exceeds the empirically permissible concentration (such as when the SS permissible concentration value is set to 40 mg / L), while the secondary detection component 42 simultaneously detects that the DO outflow from the lifting device 1 does not exceed the empirically permissible concentration (such as when the DO permissible content value is set to 3.5 mg / L), in order to prevent the contaminants from entering the bottom of the type A purification packing bed component 2 and being difficult to backwash out of the type A purification packing bed component 2 system, and the SS contaminants can still be intercepted by the upper part of the packing even if they enter the upper part of the type A purification packing bed component 2, and can be efficiently removed out of the type A purification packing bed component 2 system through subsequent pulse backwashing from bottom to top in countercurrent with the inlet water, the type A purification packing bed component 2 of the outlet water of the lifting device 1 can adopt a downward flow state, that is, a top-down mode is more suitable.

[0177] In the M43 mode, the outlet water of the lifting device 1 enters through the top of the A-type purification packing bed assembly 2, reacts and discharges water from the bottom of the A-type purification packing bed assembly 2, and then flows into the bottom of the B-type purification packing bed assembly 3, and reacts and discharges water from the top of the B-type purification packing bed assembly 3 and flows into the liquid collecting device 4, that is, the flow of the A-type purification packing bed assembly 2 and the B-type purification packing bed assembly 3 successively adopts the top-in and bottom-out mode of the A-type purification packing bed assembly 2 and the bottom-in and top-out mode of the B-type purification packing bed assembly 3.

[0178] In the M44 mode, the outlet water of the lifting device 1 enters through the top of the A-type purification packing bed assembly 2, reacts and discharges water from the bottom of the A-type purification packing bed assembly 2, and then flows into the top of the B-type purification packing bed assembly 3, and reacts and discharges water from the bottom of the B-type purification packing bed assembly 3 and flows into the liquid collecting device 4, that is, the flow of the A-type purification packing bed assembly 2 and the B-type purification packing bed assembly 3 adopts the top-in and bottom-out mode of the A-type purification packing bed assembly 2 and the top-in and bottom-out mode of the B-type purification packing bed assembly 3 respectively.

[0179] It should be noted that by opening and closing necessary valves and devices, three flushing recovery modes can be adopted: single air source flushing, single raw water flushing, and combined air source and water source mixed flushing. The A-type purification packing bed assembly 2, the B-type purification packing bed assembly 3 and the pipeline facilities can be flushed one by one or flushed synchronously and waste liquid collected. The primary detection assembly 14 and the secondary detection assembly 42 are used to assist in observation and feedback warning to mobilize the start-up of the air source flushing device 6, or to start the flushing source system at a fixed periodic frequency to ensure the long-term stable operation of the system.

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

[0181] It can be seen from the examples that the rural sewage denitrification and phosphorus removal system and water treatment method of the present invention can effectively achieve the nitrogen and phosphorus purification tail water quality goals of TN less than 20 mg / L (or TN removal concentration exceeds 6 mg / L, or TN removal rate exceeds 30%), TP less than 1.0 mg / L (or TP removal concentration exceeds 0.6 mg / L, or TP removal rate exceeds 50%). In addition, through the fine filter bed deep filtration and net capture interception of type A or / and type B purification packing bed, the synergistic multi-pollutant removal effect of tail water SS less than 20 mg / L or SS removal concentration exceeding 20 mg / L can be achieved.

[0182] It should be noted that, in the absence of conflict, the features in the embodiments of this application may be combined with each other.

[0183] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A rural sewage denitrification and phosphorus removal system, characterized in that: include: Lifting device, purification device, liquid collecting device, backwash waste liquid device, air source flushing device, serial piping device and water distribution device; The lifting device is used to receive rural sewage and pump the raw water to the purification device, and the purification device includes two purification reactor units, which are used to perform biological denitrification and chemical phosphorus removal purification treatments on the raw water respectively; The purification reactor units are respectively provided with biological denitrification packing beds and chemical dephosphorization packing beds, the liquid collecting 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 pipes, the backwash waste liquid device is used to receive the backwash waste water generated by backwashing, and the series pipe device is arranged between different devices and two purification reactor units for branching and transporting rural sewage; The water distribution device is arranged on the purification device, and includes a bottom uniform flow water distributor for uniformly distributing the inlet and outlet water at the bottom, and a slag cutting and water distribution component for cutting and uniformly distributing the inlet and outlet water at the top; The slag cutting and water distribution assembly comprises a top uniform flow water distributor and a slag cutting drain located above the top uniform flow water distributor.

2. The rural sewage denitrification and phosphorus removal system according to claim 1, characterized in that: The purification reactor unit is an underground module unit or an above-ground module unit, including a purification reactor made of corrosion-resistant material, and two purification reactors are respectively provided with fixed bed filler layers for biological denitrification or chemical dephosphorization; The fixed bed packing layer includes a dephosphorization packing bed and a denitrification packing bed, both of which are slow-release packings and have filtering functions. With respect to the flow direction of rural sewage, the dephosphorization packing bed and the denitrification packing bed are connected in series in a front or inverted manner. The dephosphorization filler bed is filled with iron-based, iron-carbon-based and iron-calcium-based fillers with positive trivalent metal ions and composite dephosphorization, or one or more of carbon fiber, graphene fiber or Cucurbitaceae plant fiber bundles are added therein as a bed strengthening base material; The denitrification filler bed is filled with autotrophic or heterotrophic driven fillers that can provide good denitrification reaction electron donors and composite denitrification, or one or more of carbon fiber, graphene fiber or Cucurbitaceae fiber bundles are added therein as bed strengthening base materials.

3. The rural sewage denitrification and phosphorus removal system according to claim 2, characterized in that: Internal gaps for water inlet and outlet are respectively arranged on the top and bottom sides of the fixed bed packing layer, and the bottom uniform flow water distributor and the slag cutting water distribution assembly are respectively arranged in the internal gaps; An upper water inlet pipe and a lower water inlet pipe are respectively arranged inside the two purification reactors, and an upper water outlet pipe and a lower water outlet pipe are respectively connected to the two purification reactors; Different water inlet pipes and water outlet pipes are respectively provided with control valves located outside the purification reactor; The upper water inlet pipe member and the upper water outlet pipe member, as well as the lower water inlet pipe member and the lower water outlet pipe member are respectively arranged on two sides of the purification reactor in an opposite manner.

4. The rural sewage denitrification and phosphorus removal system according to claim 3, characterized in that: The lower water inlet pipe extends below the bottom uniform flow water distributor, and the extended end is retained at the center of the bottom uniform flow water distributor; The upper water inlet pipe extends above the slag cut-off steam trap, and the extended end is retained in the central part of the slag cut-off steam trap; The connection point of the lower water outlet pipe on the purification reactor is located between the fixed bed packing layer and the bottom uniform flow water distributor; The connection point of the upper water outlet pipe member on the purification reactor is located above the slag cut-off steam trap.

5. The rural sewage denitrification and phosphorus removal system according to claim 1, characterized in that: The bottom uniform flow water distributor and the top uniform flow water distributor are respectively made of transparent PVC material, both of which are three-dimensional flat structures and have the same transverse cross-section shape as the transverse cross-section of the purification reactor; The bottom uniform flow water distributor and the top uniform flow water distributor respectively include a water outlet disc and a water inlet disc, and the water inlet disc and the water outlet disc are both provided with a plurality of water holes arranged in an annular manner, the number of water holes arranged on the water outlet disc is greater than the number of water holes arranged on the water inlet disc, and a hollow water distribution cavity is provided between the water inlet disc and the water outlet disc; The raw water enters the uniform flow water distributor from bottom to top or from top to bottom and flows into the purification filler through the water holes.

6. The rural sewage denitrification and phosphorus removal system according to claim 1, characterized in that: The slag cut-off steam trap and the top uniform flow water distributor are vertically opposite to each other, and a gap of 5-10 cm is left between the bottom of the slag cut-off steam trap and the top uniform flow water distributor; The slag cut-off drain device is a double-layer filter screen structure that is bent and concave inward, including a primary slag cut-off drain layer located at the upper part and a secondary slag cut-off drain layer located at the lower part; The first-level slag cutting hydrophobic layer and the second-level slag cutting hydrophobic layer are stacked up and down and include a hollow hydrophobic cavity located therebetween.

7. The rural sewage denitrification and phosphorus removal system according to claim 6, characterized in that: The slag cut-off steam trap comprises a first slag cut-off steam trap having a semicircular ring shape in vertical cross section, or the slag cut-off steam trap comprises a second slag cut-off steam trap having a crescent shape in vertical cross section; The horizontal cross-sectional diameter of the first-stage slag cut-off drain layer on the first slag cut-off drain device is smaller than the horizontal cross-sectional diameter of the second-stage slag cut-off drain layer, and the diameter difference is 4-20 cm; The horizontal cross-sectional diameter of the first-level slag cut-off drain layer on the second slag cut-off drain device is the same as the horizontal cross-sectional diameter of the second-level slag cut-off drain layer; The first-level slag cut-off water-repellent layer and the second-level slag cut-off water-repellent layer both include a plurality of annular segment bars spaced inside and outside and a plurality of straight segment bars spaced evenly around the annular segment bars; The gap between the straight bars and the annular bars on the primary slag cut-off hydrophobic layer is larger than the gap between the straight bars and the annular bars on the secondary slag cut-off hydrophobic layer; A single set of the slag cut-off drain is fixedly connected to the top of the purification reactor via a mounting member.

8. The rural sewage denitrification and phosphorus removal system according to claim 6, characterized in that: The slag cut-off steam trap comprises a plurality of sets arranged above the top uniform flow water distributor, and the plurality of sets of slag cut-off steam traps are evenly and symmetrically spaced relative to the top uniform flow water distributor in the circumferential direction.

9. The rural sewage denitrification and phosphorus removal system according to claim 1, characterized in that: 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 collecting device includes a secondary detection component, the backwash waste liquid device includes a backwash waste liquid control valve, a short-circuit line and a short-circuit line control valve are arranged between the lifting device and the liquid collecting device, and the control system is electrically connected to the electronic control equipment and control valves in different devices, as well as to the purification device and the control valve in the series line device.

10. A water treatment method, characterized in that: The rural sewage denitrification and phosphorus removal system according to claim 1 is characterized in that it includes a plurality of different operation modes to adapt to the raw water quality and water volume of the treated water with high and low loads; The operating modes include: M1, when the raw water in the lifting device does not need to be treated, the rural sewage in the lifting device flows directly into the liquid collecting device by gravity; M2, when the raw water denitrification demand or phosphorus removal demand in the lifting device only includes its single enhanced water quality improvement demand, the raw water is purified by biological denitrification or chemical phosphorus removal through one of the purification reactor units; Also in M2 mode, including: M21, when the DO of the outflow from the lifting device exceeds the empirical allowable content, in order to prevent the free fall of the upper part of the self-purification reactor unit from further falling and enriching the water with oxygen, under the condition that the outflow SS of the lifting device does not exceed the empirical allowable concentration, the outflow of the lifting device enters the purification reactor unit from bottom to top; M22, when the SS outflow from the lifting device exceeds the empirical allowable concentration, under the condition that the DO outflow from the lifting device does not exceed the empirical allowable concentration, in order to prevent the contaminants from entering the bottom of the purification reactor unit and being difficult to be removed from the packing by backwashing, and the SS contaminants can still be intercepted by the upper part of the packing even if they enter the upper part of the purification reactor unit, and can be efficiently removed from the packing by subsequent backwashing, the effluent of the lifting device enters the purification reactor unit from top to bottom; M3, when the raw water denitrification demand or phosphorus removal demand in the lifting device only includes its single enhanced water quality improvement demand, the raw water is purified by biological denitrification or chemical phosphorus removal through another purification reactor unit in the M2 mode; Also in M3 mode, including: M31, when the DO of the outflow from the lifting device exceeds the empirical allowable content, in order to prevent the free fall of the upper part of the self-purification reactor unit from further falling and enriching the water with oxygen, under the condition that the outflow SS of the lifting device does not exceed the empirical allowable concentration, the effluent of the lifting device enters the purification reactor unit from bottom to top; M32, when the SS outflow from the lifting device exceeds the empirical allowable concentration, under the condition that the DO outflow from the lifting device does not exceed the empirical allowable concentration, in order to prevent the contaminants from entering the bottom of the purification reactor unit and being difficult to be removed from the packing by backwashing, the SS contaminants can still be intercepted by the upper part of the packing even if they enter the upper part of the purification reactor unit, and can be efficiently removed from the packing by subsequent backwashing, the effluent of the lifting device enters the purification reactor unit from top to bottom; M4, when the total nitrogen and total phosphorus indicators of the raw water in the lifting device cannot meet the expected water quality, the raw water is purified by biological denitrification and chemical dephosphorization through two purification reactor units at the same time; At the same time, in the M4 mode, when the DO of the outflow from the lifting device exceeds the empirical allowable content, in order to prevent the upper free fall of the self-purification reactor unit from further falling and enriching water with oxygen, under the condition that the outflow SS of the lifting device does not exceed the empirical allowable concentration, the following two modes are used for treatment: M41, the effluent of the lifting device enters the first-stage purification reactor unit from bottom to top, and the effluent of the first-stage purification reactor unit enters the second-stage purification reactor unit from top to bottom, and flows into the liquid collecting device after being treated; M42, the effluent of the lifting device enters the first-stage purification reactor unit from bottom to top, and the effluent of the first-stage purification reactor unit enters the second-stage purification reactor unit from bottom to top, and flows into the liquid collecting device after being treated; At the same time, in the M4 mode, when the SS outflow from the lifting device exceeds the empirical allowable concentration, under the condition that the DO outflow from the lifting device does not exceed the empirical allowable concentration, in order to prevent the contaminants from entering the bottom of the purification reactor unit and being difficult to remove from the packing by backwashing, the SS contaminants can still be intercepted by the upper part of the packing even if they enter the upper part of the purification reactor unit, and can be efficiently removed from the packing by subsequent backwashing, and are processed through the following two modes: M43, the effluent of the lifting device enters the first-stage purification reactor unit from top to bottom, and the effluent of the first-stage purification reactor unit enters the second-stage purification reactor unit from bottom to top, and flows into the liquid collecting device after being treated; M44, the effluent of the lifting device enters the first-stage purification reactor unit from top to bottom, and the effluent of the first-stage purification reactor unit enters the second-stage purification reactor unit from top to bottom, and flows into the liquid collecting device after being treated.

Images