Unpowered ecological filter

Abstract

The invention relates to the technical field of sewage treatment, and provides an unpowered ecological filter which is characterized in that a front sedimentation tank and a sub-filter are sequentially arranged in the horizontal direction and are sequentially communicated, so that wastewater can sequentially pass through the front sedimentation tank and the sub-filter from front to back according to the arrangement sequence, and the direction is defined as a filtering direction; the first sub-filter tank in the filtering direction is a first-stage sub-filter tank, the first-stage sub-filter tank is filled with pebbles and coarse sand, the pebbles are used for intercepting medium-fine particles of 1-3mm, such as fine silt groups and hair bundles, and meanwhile, the pebbles are used for bearing the water flow impact of supernate of a front sedimentation tank to prevent filler from being scattered, the coarse sand is used for intercepting small-particle-size solid suspended particles, and the coarse sand is used for bearing the water flow impact of the supernate of the front sedimentation tank to prevent the filler from being scattered. And leaked large particles are prevented from entering the second-stage sub-tank and being embedded into zeolite micropores to cause blockage.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the technical field of sewage treatment, in particular, to a non-powered ecological filter. BACKGROUND

[0002] The non-powered ecological filter is an integrated non-powered treatment device specially used for treating rural gray water. The front end can be directly connected to the indoor kitchen, shower room and laundry room. The washing gray water can flow into the device by gravity flow. After a series of biological treatment and purification, the effluent quality meets the second standard of Hebei Province "Rural Domestic Sewage Discharge Standard" (DB13 / 2171-2020), which can meet the requirements of comprehensive reuse of farmers. The device is mainly used for single household or multi-household combined sewage treatment in rural areas with scattered sewage discharge and imperfect pipe network. When used in restaurants and farmhouses, an oil separation tank needs to be set at the front end.

[0003] The device usually includes multiple sub-filter pools. The pollutants are gradually intercepted by multiple stages in series. The filter pool is divided into several independent sub-filter pools along the direction of wastewater flow. Each sub-filter pool is filled with a single type of filler, such as egg stones in the front stage, zeolite and volcanic rock in the middle and rear stages. Each sub-filter pool is connected to each other through the through holes in the bottom or side wall. The wastewater flows through each stage by gravity flow. The suspended solids and organic matter are removed by using the physical interception and adsorption of different fillers. However, the gradation of single filler in single stage lacks transition. The porosity of large particle size filler in the front stage is high, which cannot effectively intercept fine particles. These fine pollutants enter the fine particle size filler in the rear stage with water flow, which easily embeds into the filler pores to form physical blockage. SUMMARY

[0004] To overcome the above-mentioned defects, the present application provides a non-powered ecological filter, which solves the technical problem of the lack of transition in the gradation of single filler in single stage, the high porosity of large particle size filler in the front stage, which cannot effectively intercept fine particles, and the easy embedding of these fine pollutants into the filler pores to form physical blockage.

[0005] According to one aspect, at least one embodiment of the present application provides a non-powered ecological filter, which includes: a filter pool body, the filter pool body includes a horizontal arrangement of a front sedimentation tank and a plurality of sub-filter pools, the front sedimentation tank and the plurality of sub-filter pools are arranged and communicated in sequence along the horizontal direction, so that the wastewater can pass through the front sedimentation tank and the plurality of sub-filter pools in sequence from front to back in the arrangement order, and the direction is defined as the filtration direction. The sub-filter pool located at the first position in the filtration direction is a first-stage sub-pool. The first-stage sub-pool is filled with egg stones and coarse sand. A first-stage water guide pipe is arranged on the upper part of the pool wall of the first-stage sub-pool and is communicated with the upper part of the front sedimentation tank. The first-stage water guide pipe extends downward and approaches the bottom of the first-stage sub-pool.

[0006] For example, in at least one embodiment of the present application, in the unpowered ecological filter, the first-stage sub-tank is divided into a first-stage first section, a first-stage second section and a first-stage third section from bottom to top, the first-stage first section is filled with 90% pebbles and the rest is coarse sand, the first-stage second section is filled with 70% pebbles and the rest is coarse sand, and the first-stage third section is filled with 50% pebbles and the rest is coarse sand, wherein the particle size of the coarse sand in the first-stage first section is smaller than that in the first-stage second section, and the particle size of the coarse sand in the first-stage second section is smaller than that in the first-stage third section.

[0007] For example, in at least one embodiment of the present application, in the unpowered ecological filter, the rear of the first-stage sub-tank is a second-stage sub-tank, the second-stage sub-tank is filled with volcanic rock and zeolite, and a second-stage water guide pipe is arranged on the upper part of the tank wall of the second-stage sub-tank and communicates with the upper part of the first-stage sub-tank, and the second-stage water guide pipe extends downward to be close to the bottom of the second-stage sub-tank.

[0008] For example, in at least one embodiment of the present application, in the unpowered ecological filter, the second-stage sub-tank is divided into a second-stage first section, a second-stage second section and a second-stage third section from bottom to top, the second-stage first section is filled with 80% volcanic rock and the rest is fine sand, the second-stage second section is filled with 60% zeolite and the rest is volcanic rock, and the second-stage third section is filled with 95% zeolite and the rest is volcanic rock.

[0009] For example, in at least one embodiment of the present application, in the unpowered ecological filter, the rear of the second-stage sub-tank is a third-stage sub-tank, the third-stage sub-tank is filled with volcanic rock, activated carbon and fine sand, and a third-stage water guide pipe is arranged on the upper part of the tank wall of the third-stage sub-tank and communicates with the upper part of the second-stage sub-tank, and the third-stage water guide pipe extends downward to be close to the bottom of the third-stage sub-tank.

[0010] For example, in at least one embodiment of the present application, in the unpowered ecological filter, the third-stage sub-tank is divided into a third-stage first section, a third-stage second section and a third-stage third section from bottom to top, the height ratio of the third-stage first section, the third-stage second section and the third-stage third section is 3:4:2, the third-stage first section is filled with volcanic rock, the third-stage second section is filled with activated carbon, and the third-stage third section is filled with fine sand.

[0011] For example, in at least one embodiment of the present application, in the unpowered ecological filter, the rear of the third-stage sub-tank is a fourth-stage sub-tank, the fourth-stage sub-tank is filled with limestone and zeolite, and a fourth-stage water guide pipe is arranged on the upper part of the tank wall of the fourth-stage sub-tank and communicates with the upper part of the third-stage sub-tank, and the fourth-stage water guide pipe extends downward to be close to the bottom of the fourth-stage sub-tank.

[0012] For example, in at least one embodiment of the present application, in the unpowered ecological filter, the fourth-stage sub-tank is divided into a fourth-stage first section, a fourth-stage second section and a fourth-stage third section from bottom to top, the height of the fourth-stage first section, the fourth-stage second section and the fourth-stage third section is equal, the fourth-stage first section is filled with 80% limestone and the rest is zeolite, the fourth-stage second section is filled with 60% limestone and the rest is zeolite, and the fourth-stage third section is filled with 40% limestone and the rest is zeolite.

[0013] For example, the unpowered ecological filter provided by at least one embodiment of the present application further comprises: a back sedimentation tank located behind the fourth sub-tank, a water outlet pipe being arranged on the upper part of the tank wall of the back sedimentation tank and being in communication with the upper part of the fourth sub-tank, and a drain being further arranged on the tank wall of the back sedimentation tank away from the fourth sub-tank. The top end of the first water guide pipe, the second water guide pipe, the third water guide pipe, the fourth water guide pipe and the water outlet pipe gradually decreases in height, and the height of the drain is lower than the height of the water outlet pipe.

[0014] For example, the unpowered ecological filter provided by at least one embodiment of the present application further comprises: a back sedimentation tank located behind the fourth sub-tank, a water outlet pipe being arranged on the upper part of the tank wall of the back sedimentation tank and being in communication with the upper part of the fourth sub-tank, and a drain being further arranged on the tank wall of the back sedimentation tank away from the fourth sub-tank.

[0015] The embodiment of the present application has the following beneficial effects: In the present application, 90% of 10mm-20mm pebbles are filled in the first section of the first stage, the pebbles are densely packed, the gap rate is about 30%-35%, the actual gap size is about 3mm-5mm, the pebbles serve as the first filtration of sewage and need to intercept 1mm-3mm medium-fine particles such as small silt groups and hair bundles, and meanwhile, the pebbles can withstand the water flow impact of the supernatant of the front sedimentation tank and avoid being washed away. Therefore, 2mm-4mm coarse sand is also filled, the coarse sand is smaller than the upper limit of the actual gap of the pebbles, i.e. 5mm, to avoid blockage, and the coarse sand is larger than 1 / 2 of the lower limit of the actual gap of the pebbles, i.e. 3mm, about 1.5mm, to avoid being washed up by the water flow. If the coarse sand is too fine, it will be suspended with the water flow, resulting in the second emptying of the pebble gap. The second section of the first stage is located above the first section of the first stage, 70% of the pebbles expand the gap to 5mm-8mm, and 30% of 4mm-7mm coarse sand is mixed, for intercepting 2mm-5mm transition particles and gently connecting the water flow speed of the first section of the first stage to ensure the continuity of filtration. In the third section of the first stage, 50% of the pebbles form 8mm-12mm gaps, and 50% of 7mm-10mm coarse sand is filled to intercept 3mm-6mm residual particles, to avoid large particles from leaking into the second sub-tank and being embedded in the zeolite micropores to cause blockage. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments of the present application will be briefly introduced. Obviously, the drawings in the following description are only some example embodiments of the present application. Those skilled in the art can obtain other drawings according to the contents of the example embodiments of the present application and the drawings without any creative effort.

[0017] Figure 1 The structure diagram of the unpowered ecological filter in one embodiment of the present application.

[0018] Fig. 100, front sedimentation tank; 200, sub-filter tank; 210, first-stage sub-tank; 211, first-stage first section; 212, first-stage second section; 213, first-stage third section; 214, first-stage water guide pipe; 220, second-stage sub-tank; 221, second-stage first section; 222, second-stage second section; 223, second-stage third section; 224, second-stage water guide pipe; 230, third-stage sub-tank; 231, third-stage first section; 232, third-stage second section; 233, third-stage third section; 234, third-stage water guide pipe; 240, fourth-stage sub-tank; 241, fourth-stage first section; 242, fourth-stage second section; 243, fourth-stage third section; 244, fourth-stage water guide pipe; 300, back sedimentation tank; 310, water outlet pipe; 320, water outlet; 400, plant; 500, water-permeable partition; 600, filtration direction. DETAILED DESCRIPTION

[0019] The application will be further described below in conjunction with the drawings and embodiments. It should be understood that the specific embodiments described herein merely serve to explain the application, and do not limit the application.

[0020] For the sake of simplicity of the drawings, only the parts related to the application are shown in each drawing, which do not represent the actual structure of the product. In addition, for the sake of simplicity of the drawings and easy understanding, in some drawings, only one of the parts having the same structure or function is shown schematically, or only one of them is marked. In this text, "one" not only means "only one", but also means "more than one", and "several" includes "two" and "more than two".

[0021] In this text, it should be noted that unless otherwise explicitly specified and limited, the terms "mount", "connect", and "connection" should be understood broadly, for example, can be fixed connection, can be detachable connection, or integrally connected; can be mechanical connection, or electrical connection; can be directly connected, or indirectly connected through an intermediate medium, or the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the application can be understood according to the specific circumstances.

[0022] In the application, unless otherwise explicitly specified and limited, the "upper" or "lower" of the first feature to the second feature can include that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the "upper", "above", and "on" of the first feature to the second feature includes that the first feature is directly above and obliquely above the second feature, or only means that the horizontal height of the first feature is higher than that of the second feature. The "lower", "below", and "under" of the first feature to the second feature includes that the first feature is directly below and obliquely below the second feature, or only means that the horizontal height of the first feature is less than that of the second feature.

[0023] In the description of this embodiment, terms such as "upper," "lower," "left," and "right" are based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of description and simplification of operation, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0024] Furthermore, in the description of this application, the terms "first," "second," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0025] like Figure 1 As shown, this illustrates a non-powered ecological filter pond according to an embodiment of the present invention, mainly used for treating rural greywater. In some examples, the filter pond mainly includes a pre-sedimentation tank 100, a post-sedimentation tank 300, and a sub-filter pond 200 located between the pre-sedimentation tank 100 and the post-sedimentation tank 300. In this embodiment, the arrangement direction is defined as the filtration direction 600, and the pre-sedimentation tank 100 is located in front of the sub-filter pond 200, that is, the rural greywater to be treated is first discharged into the pre-sedimentation tank 100. As a reference example, the arrangement of the pre-sedimentation tank 100 is as follows: a circular hole with a diameter of 110mm is drilled at the inlet and connected to the outlet pipe network as the inlet of the non-powered ecological filter pond. The specific size can be adjusted according to actual needs and is not limited here. A downward-facing PVC elbow is installed at the inlet of the filter body, and a PVC pipe is connected to guide the water downwards. The downward-facing PVC pipe extends close to the bottom of the pre-sedimentation tank 100. Wastewater flows into the bottom of the pre-sedimentation tank 100 through the pipe. In the pre-sedimentation tank 100, sludge, sediment, etc. settle due to gravity, avoiding clogging of the packing material in the subsequent primary sub-tank 210. At the same time, it buffers the peak flow fluctuations of water use and stably supplies water to the subsequent sub-filters 200. The clear liquid on the upper layer of the pre-sedimentation tank 100 is transported to the primary sub-tank 210 through the primary water guide pipe 214. After being filtered by the primary sub-tank 210, secondary sub-tank 220, tertiary sub-tank 230 and quaternary sub-tank 240, it enters the post-sedimentation tank 300 and is discharged through the drain outlet 320 set on the tank wall of the post-sedimentation tank 300. The number of sub-filters 200 can be adjusted according to actual needs and is not limited here.

[0026] In a traditional example, the sub-filter 200 includes multiple sub-filters, and the sub-filters are usually separated by a single packing material. For example, in a filter body example including four sub-filters 240, the packing materials of the four sub-filters 240 are sequentially arranged from the filtration direction 600 as follows: pebbles with a particle size of 10mm-20mm, zeolite / multifunctional activated biological filter media with a particle size of 5mm-10mm, volcanic rock / high-performance microbial carrier with a particle size of 0.5mm-10mm, and limestone with a particle size of 5mm-10mm.

[0027] In the traditional example, the first sub-pool 210 is filled with pebbles with a particle size of 10-20 mm, which can only intercept large particles with a particle size of >10 mm. The single pebble pore is large, and small suspended solid particles can easily pass through the filter material layer, causing subsequent fine filler blockage and affecting the stability of the permeability coefficient. At the same time, the specific surface area of the pebble is small, about 0.1 m 2 / g-0.2 m 2 / g, and the amount of microorganism attachment is small, which cannot effectively degrade the organic matter in the sewage, such as small molecule organic acids and carbohydrates, resulting in difficulty in reducing the COD value. The COD is the chemical oxygen demand, which is the mass of oxygen corresponding to the oxidizing agent consumed when all the reducing substances in the water, mainly organic matter, and a small amount of inorganic reducing substances, are oxidized by chemical oxidizing agents such as potassium dichromate and potassium permanganate. The COD value is used to indirectly measure the total content of organic matter in water. The higher the COD value, the more organic matter in the water, such as oil, detergent residues, and food residues in kitchen wastewater, and microbial metabolites in domestic wastewater, and the higher the degree of water pollution.

[0028] In the traditional example, the second sub-pool 220 is filled with zeolite / multifunctional active biological filter material with a particle size of 5-10 mm. Although the zeolite has the ability to adsorb ammonia nitrogen in the sewage, the single zeolite lacks a carrier function for microorganism attachment. The nitrogen-containing substances adsorbed by the zeolite, such as ammonium ions, cannot be effectively degraded by microorganisms, resulting in the zeolite reaching adsorption saturation within 1-2 months. After adsorption saturation, the removal effect of the zeolite on ammonia nitrogen in the sewage will gradually decrease, and the corresponding effluent ammonia nitrogen concentration will gradually rise and exceed the predetermined value, requiring frequent replacement of the zeolite, with a replacement frequency higher than the predetermined replacement period of 2-3 years.

[0029] In the traditional example, the third sub-pool 230 is filled with volcanic rock / high-performance microbial carrier with a particle size of 0.5-10 mm. Although the volcanic rock can serve as a carrier for microorganism attachment, and the specific surface area is about 1 m 2 / g-2 m 2 / g, the single volcanic rock has weak removal ability for various phosphorus-containing substances corresponding to total phosphorus (TP) in water, including soluble phosphate such as phosphate ions, particulate phosphorus such as phosphorus attached to suspended solids, and organic phosphorus such as phosphorus-containing compounds in food residues and detergents. At the same time, the volcanic rock has a large particle size span of 0.5-10 mm, which can easily cause filler stratification, with fine particles sinking and coarse particles floating, resulting in uneven distribution of filler pores in the pool. The water flow easily short-circuits through the areas with larger pores, failing to fully contact the filler and microorganisms, and ultimately making the hydraulic retention time fail to reach the designed 3-4.8 days, affecting the degradation effect of organic matter in the sewage and reducing the organic matter removal rate.

[0030] In the traditional example, the fourth sub-tank 240 is filled with limestone with a particle size of 5mm-10mm, which can remove the soluble phosphate salt corresponding to total phosphorus (TP) in water, such as phosphate ions, through calcium carbonate precipitation, and the reaction formula is: Ca 2+ +PO4 3- →Ca3(PO4)3↓, but single limestone does not have the function of degrading organic matter in wastewater, and cannot remove organic matter producing chemical oxygen demand (COD) in water through microbial or chemical reactions. At the same time, limestone itself has strong alkalinity, with a pH value of about 8.5-9.5, and if used alone, it may cause the pH value of the effluent after treatment to exceed the design range; and this alkaline environment will affect the activity of microorganisms on the previous stage of volcanic rock, and the suitable pH value range of such microorganisms is 6.5-7.5, and after the pH value deviates from the suitable range, the ability of the microorganisms to degrade organic matter will decrease, thereby affecting the overall wastewater treatment effect.

[0031] Based on the problems faced by the traditional example scheme described above, in the example of the present application, a sub-filter tank 200 with different filler structures is provided, and in the present example, the sub-filter tank 200 includes four, namely a first sub-tank 210, a second sub-tank 220, a third sub-tank 230 and a fourth sub-tank 240, wherein the first sub-tank 210 is divided into a first section 211, a second section 212 and a third section 213 from bottom to top, and the heights of the three sections are equal. The first section 211 is filled with 90% of 10mm-20mm pebbles and the rest is 2mm-4mm coarse sand, the second section 212 is filled with 70% of 10mm-20mm pebbles and the rest is 4mm-7mm coarse sand, and the third section 213 is filled with 50% of 10mm-20mm pebbles and the rest is 7mm-10mm coarse sand. The 10-20mm particle size pebbles have high strength and moderate particle size, which can form a stable pore structure to avoid being washed away and deformed by the water flow, and also provide filling space for the coarse sand; Specifically, the first stage 211 is filled with 90% of 10mm-20mm pebbles, which are densely packed with a porosity of about 30%-35% and an actual gap size of about 3mm-5mm. The first stage 211 serves as the first filtration of sewage and needs to intercept 1mm-3mm medium-fine particles such as fine silt and hair bundles. At the same time, the first stage 211 can withstand the impact of the water flow from the supernatant of the front sedimentation tank 100 to avoid the filler being washed away. Therefore, the first stage 211 is also filled with 2mm-4mm coarse sand. The coarse sand is smaller than the upper limit of the actual gap of the pebbles, i.e., 5mm, to avoid blockage, and is larger than half of the lower limit of the actual gap of the pebbles, i.e., 3mm, i.e., about 1.5mm, to avoid being washed up by the water flow. If the coarse sand is too fine, it will be suspended with the water flow, resulting in a secondary void between the pebbles. The second stage 212 of the first stage is located above the first stage 211. The 70% pebbles expand the gap to 5mm-8mm, and the 30% 4mm-7mm coarse sand is mixed to intercept 2mm-5mm transition particles, while gradually connecting the water flow speed of the first stage 211 to ensure the continuity of filtration. In the third stage 213 of the first stage, 50% of the pebbles form a gap of 8mm-12mm, and 50% of the 7mm-10mm coarse sand is filled to intercept 3mm-6mm residual particles to prevent large particles from entering the second stage 220 and being embedded in the zeolite micropores to cause blockage.

[0032] Further, the embodiment of the present application also proposes a secondary sub-pool 220, which receives the effluent of the primary sub-pool 210. After the filtration of the primary sub-pool 210, most of the suspended solids with a size of ≥0.5 mm in the sewage have been intercepted, and the remaining pollutants mainly include small suspended solids with a size of 0.1 mm-0.5 mm, organic matters (such as small-molecule carbohydrates and organic acids) that generate chemical oxygen demand (COD), and nitrogen-containing substances (such as ammonium ions and free ammonia) that generate ammonia nitrogen (NH3-N). The traditional secondary sub-pool 220 uses single-stage single packing with full volcanic rock or full zeolite. The full volcanic rock has weak adsorption capacity for the above-mentioned organic matters and nitrogen-containing substances; and the full zeolite is easy to be blocked in the pores by small suspended solids. Therefore, in the present example, the secondary sub-pool 220 also adopts a three-stage equal-height layered design. The secondary first stage 221 is located at the lowermost end, directly receives the effluent of the primary sub-pool 210, and is filled with 80% of 10 mm-20 mm volcanic rock and the rest of 0.5 mm-1 mm fine sand. The volcanic rock is selected as the main filling material of the secondary first stage 221 because its Mohs hardness reaches 5-6 grade, and the single-particle compressive strength is ≥10 MPa, which is higher than that of the zeolite with Mohs hardness of 4-5 grade. After being stacked at a high proportion of 80%, the volcanic rock can form a stable bottom skeleton, avoid the displacement of the filling material in the secondary sub-pool 220, and protect the structural stability of the zeolite layer of the secondary second stage 222. In addition, the volcanic rock has a honeycomb-like connected pore structure with a porosity of 40%-50%, which can quickly guide the water flow. If non-porous fillers such as pebbles are used, they can resist impact but cannot adsorb pollutants. If zeolite is used, although it can adsorb pollutants, the pores are easy to be compacted by impact, resulting in a decrease in water guiding efficiency. The middle-layer secondary second stage 222 is filled with 60% of 10 mm-20 mm zeolite and 40% of 10 mm-20 mm volcanic rock, which serves as a transition layer. The 10 mm-20 mm zeolite preliminarily adsorbs organic matters that generate chemical oxygen demand (COD) and nitrogen-containing substances that generate ammonia nitrogen (NH3-N), and the 40% of 10 mm-20 mm volcanic rock maintains the pores and smoothly guides the water, avoids the change of water resistance due to the increase of the proportion of zeolite, and prevents anaerobic accumulation of water. The uppermost secondary third stage 223 is filled with 95% of 2 mm-5 mm zeolite and 5% of 5 mm-10 mm volcanic rock. The high proportion of zeolite can provide more adsorption sites, improve the removal efficiency of organic matters and nitrogen-containing substances, and reduce the values of chemical oxygen demand (COD) and ammonia nitrogen (NH3-N). A small amount of volcanic rock supports the gaps to prevent the compaction of zeolite and ensures the full contact between the water flow and the filling material.

[0033] Further, the tertiary sub-pool 230 is divided into a tertiary first section 231, a tertiary second section 232 and a tertiary third section 233 from bottom to top, and the height ratio of the tertiary first section 231, the tertiary second section 232 and the tertiary third section 233 is 3:4:2. The tertiary first section 231 is filled with volcanic rock, the tertiary second section 232 is filled with activated carbon, and the tertiary third section 233 is filled with fine sand. The tertiary sub-pool 230 receives the secondary effluent, the lowermost tertiary first section 231 is filled with 100% volcanic rock, the tertiary second section 232 is filled with 100% activated carbon, and the tertiary third section 233 is filled with fine sand. The volcanic rock in the tertiary first section 231 can resist the impact of the secondary effluent, prevent the upper activated carbon from being displaced due to impact, and preliminarily filter the remaining small suspended solid particles, prevent fine particles from embedding into the micropores of the activated carbon to cause blockage, and solve the problem of easy saturation of traditional activated carbon directly receiving the effluent. The activated carbon in the tertiary second section 232 has a large specific surface area, and this section has a higher height to increase the contact time of the sewage and the activated carbon, fully adsorb pollutants, ensure the deep purification effect, and avoid insufficient adsorption due to insufficient height or increased water flow resistance and water accumulation due to excessive height.

[0034] Further, the tertiary sub-pool 230 is divided into a tertiary first section 231, a tertiary second section 232 and a tertiary third section 233 from bottom to top, and the height ratio of the tertiary first section 231, the tertiary second section 232 and the tertiary third section 233 is 3:4:2. The tertiary first section 231 is filled with volcanic rock, the tertiary second section 232 is filled with activated carbon, and the tertiary third section 233 is filled with fine sand. The tertiary sub-pool 230 receives the secondary effluent, the lowermost tertiary first section 231 is filled with 100% volcanic rock, the tertiary second section 232 is filled with 100% activated carbon, and the tertiary third section 233 is filled with fine sand. The volcanic rock in the tertiary first section 231 can resist the impact of the secondary effluent, prevent the upper activated carbon from being displaced due to impact, and preliminarily filter the remaining small suspended solid particles, prevent fine particles from embedding into the micropores of the activated carbon to cause blockage, and solve the problem of easy saturation of traditional activated carbon directly receiving the effluent. The activated carbon in the tertiary second section 232 has a large specific surface area, and this section has a higher height to increase the contact time of the sewage and the activated carbon, fully adsorb pollutants, ensure the deep purification effect, and avoid insufficient adsorption due to insufficient height or increased water flow resistance and water accumulation due to excessive height. 2+ 、Cd 2+ )and residual organic matter, ensuring that the effluent indicators (pH, hardness, heavy metals) meet the standards; and the equal height design ensures balanced contact time in each section, avoiding insufficient treatment in some areas.

[0035] In some examples, the back sedimentation tank 300 is located behind the fourth-stage sub-tank 240, and is in communication with the upper part of the fourth-stage sub-tank 240 through a water outlet pipe 310 on the upper part of the tank wall. A drain outlet 320 is separately arranged on the tank wall away from the fourth-stage sub-tank 240 as a final water outlet passage. The top end heights of the first-stage water guide pipe 214, the second-stage water guide pipe 224, the third-stage water guide pipe 234, the fourth-stage water guide pipe 244, and the water outlet pipe 310 are sequentially lowered, and the height of the drain outlet 320 is lower than the top end of the water outlet pipe 310. The top ends of the water guide pipes and the water outlet pipe 310 are sequentially lowered, so that the natural water pressure is formed by using the water level difference, the water flow speed is controlled by the height difference, the disturbance of the filler in the sub-tank caused by too fast flow speed is avoided, and the filtering and adsorption functions of each sub-tank are ensured to be stably exerted.

[0036] Further, the inner pipe diameter of the first-stage water guide pipe 214 is larger than that of the second-stage water guide pipe 224, the inner pipe diameter of the second-stage water guide pipe 224 is larger than that of the third-stage water guide pipe 234, and the inner pipe diameters of the third-stage water guide pipe 234, the fourth-stage water guide pipe 244, the water outlet pipe 310, and the drain outlet 320 are equal. The first-stage water guide pipe 214 receives the initial sewage, and the large pipe diameter design can reduce the water flow speed, avoid the high-speed water flow impacting the first-stage first section 211 of the first-stage sub-tank 210, and prevent the filler from being displaced or the fine sand from being lifted up. After being intercepted by the first-stage sub-tank 210, the suspended solid particles in the sewage transported by the second-stage water guide pipe 224 are reduced, and the pipe diameter is reduced to maintain the stable flow speed. If the first-stage large pipe diameter is still used, the flow speed will be reduced, which will easily cause the anaerobic water accumulation at the bottom of the second-stage sub-tank 220. After being further intercepted by the second-stage sub-tank 220, the pipe diameter of the third-stage water guide pipe 234 is continuously reduced to be consistent with the subsequent pipes. At this time, the water quality is stable, and the small pipe diameter can ensure that the flow speed is kept stable. The sewage treated by the first three-stage sub-tank 230 will have a slight water volume reduction due to the filler interception and trace evaporation. The pipe diameter reduction can avoid the slow flow speed and insufficient treatment time caused by the large pipe diameter transporting small water volume, and ensure that the hydraulic retention time of each sub-tank meets the standard. Further, the pipe diameters of the water outlet pipe 310 and the drain outlet 320 are equal, so that the sewage flows into the sedimentation tank from the fourth-stage sub-tank 240 smoothly.

[0037] Illustratively, the upper part of the sub-filter tank 200 can be provided with a planting area. An example of the arrangement of the planting area is that a plant 400 fixing device is arranged above the sub-filter tank 200 and the plant 400 is placed. The fixing device can adopt a PP material hollow bucket, the bucket wall is covered with small holes in the shape of triangles or other shapes, and the roots of the plant 400 can grow around through the small holes. The plant 400 is selected from the wet-loving greening indigenous plants 400 such as pothos, and the plant 400 can also be selected according to the preferences of the villagers. Rotting leaf soil can be used to sow flowers and cultivate seedlings. Rotting leaf soil is an important material for preparing culture soil, which can effectively improve the germination rate and accelerate the growth and development of seedlings.

[0038] It should be noted that the multiple sections of the first sub-pool 210, the second sub-pool 220, the third sub-pool 230 and the fourth sub-pool 240 can be separated by a water-permeable partition 500 made of HDPE material, for example, a water-permeable partition 500 is arranged between the first one section 211 and the first two section 212, the water-permeable partition 500 can be uniformly provided with circular through holes for water flow, the diameter of the circular through hole should not be too large, and can be determined according to the actual particle size of the filler, for example, the diameter of the circular through hole of the water-permeable partition 500 between the first one section 211 and the first two section 212 is about 3mm, the first one section 211 and the first two section 212 are both filled with coarse sand, the diameter of the circular through hole does not need to be necessarily smaller than the particle size of the coarse sand, large-diameter pebbles form a stable skeleton, and the coarse sand is filled in the gap between the pebbles and is limited in position by the surrounding pebbles. The up-and-down movement of the coarse sand through the gap is relatively small, therefore, the hole diameter should not be significantly larger than the particle size of the coarse sand, and more attention should be paid to ensuring water permeability.

[0039] It should be noted that the Figure 1 The filling pattern used in each sub-pool in the sub-filter tank 200 is only used to indicate the presence of filler in the corresponding area, and does not actually limit or imply the specific size, particle size, arrangement, filling ratio and morphological structure of the filler.

[0040] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not limiting, although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present application, and all should be covered in the scope of the claims of the present application.

Claims

1. A passive ecological filter, characterized in that The utility model relates to a sewage treatment device, including: A front sedimentation tank (100) and a sub-filter tank (200) are arranged in sequence in the horizontal direction and are communicated in sequence, so that the wastewater passes through the front sedimentation tank (100) and the sub-filter tank (200) in sequence from front to back, and the arrangement order is defined as the filtration direction (600); The sub-filter tank (200) includes a first-stage sub-tank (210) arranged adjacent to the front sedimentation tank (100), the first-stage sub-tank (210) is filled with pebbles and coarse sand, and a first-stage water guide pipe (214) is arranged in the first-stage sub-tank (210) and is communicated with the upper part of the front sedimentation tank (100), and the lower end of the first-stage water guide pipe (214) extends to the bottom of the first-stage sub-tank (210).

2. A passive ecological filter according to claim 1, characterized in that The first-stage sub-tank (210) is divided into a first-stage first section (211), a first-stage second section (212) and a first-stage third section (213) from bottom to top, the first-stage first section (211) is filled with pebbles accounting for 90% of the volume, and the rest is coarse sand, the first-stage second section (212) is filled with pebbles accounting for 70% of the volume, and the rest is coarse sand, and the first-stage third section (213) is filled with pebbles accounting for 50% of the volume, and the rest is coarse sand, wherein the particle size of the coarse sand in the first-stage first section (211) is smaller than that in the first-stage second section (212), and the particle size of the coarse sand in the first-stage second section (212) is smaller than that in the first-stage third section (213).

3. A passive ecological filter according to claim 2, characterised in that The sub-filter tank (200) further includes a second-stage sub-tank (220) located behind the first-stage sub-tank (210), the second-stage sub-tank (220) is filled with volcanic rock and zeolite, and a second-stage water guide pipe (224) is arranged in the second-stage sub-tank (220) and is communicated with the upper part of the first-stage sub-tank (210), and the second-stage water guide pipe (224) extends downward to the bottom of the second-stage sub-tank (220).

4. A passive ecological filter according to claim 3, characterised in that The second-stage sub-tank (220) is divided into a second-stage first section (221), a second-stage second section (222) and a second-stage third section (223) from bottom to top, the second-stage first section (221) is filled with volcanic rock accounting for 80% of the volume, and the rest is fine sand, the second-stage second section (222) is filled with zeolite accounting for 60% of the volume, and the rest is volcanic rock, and the second-stage third section (223) is filled with zeolite accounting for 95% of the volume, and the rest is volcanic rock.

5. A passive ecological filter according to claim 4, characterised in that The sub-filter tank (200) further includes a third-stage sub-tank (230) located behind the second-stage sub-tank (220), the third-stage sub-tank (230) is filled with volcanic rock, activated carbon and fine sand, and a third-stage water guide pipe (234) is arranged in the third-stage sub-tank (230) and is communicated with the upper part of the second-stage sub-tank (220), and the third-stage water guide pipe (234) extends downward to the bottom of the third-stage sub-tank (230).

6. A passive ecological filter according to claim 5, characterised in that The third-level sub-pool (230) is divided into a third-level first section (231), a third-level second section (232) and a third-level third section (233) from bottom to top, the height ratio of the third-level first section (231), the third-level second section (232) and the third-level third section (233) is 3:4:2, the third-level first section (231) is filled with volcanic rock, the third-level second section (232) is filled with activated carbon, and the third-level third section (233) is filled with fine sand.

7. A passive ecological filter according to claim 6, characterised in that The sub-filter tank (200) further comprises a fourth-level sub-pool (240) located behind the third-level sub-pool (230), the fourth-level sub-pool (240) is filled with limestone and zeolite, and the fourth-level sub-pool (240) is provided with a fourth-level water guide pipe (244) in communication with the upper part of the third-level sub-pool (230), the fourth-level water guide pipe (244) extends downward to the bottom of the fourth-level sub-pool (240).

8. A passive ecological filter according to claim 7, characterised in that The fourth-level sub-pool (240) is divided into a fourth-level first section (241), a fourth-level second section (242) and a fourth-level third section (243) from bottom to top, the fourth-level first section (241) is filled with 80% limestone and the rest is zeolite, the fourth-level second section (242) is filled with 60% limestone and the rest is zeolite, and the fourth-level third section (243) is filled with 40% limestone and the rest is zeolite.

9. A passive ecological filter according to claim 8, characterised in that Further comprising: A back precipitation tank (300) located behind the fourth-level sub-pool (240), the back precipitation tank (300) is provided with a water outlet pipe (310) in communication with the upper part of the fourth-level sub-pool (240), and the pool wall of the back precipitation tank (300) away from the fourth-level sub-pool (240) is further provided with a drainage port (320); The top end of the first-level water guide pipe (214), the second-level water guide pipe (224), the third-level water guide pipe (234), the fourth-level water guide pipe (244) and the water outlet pipe (310) gradually decreases in height, and the height of the drainage port (320) is lower than the top end height of the water outlet pipe (310).

10. A passive ecological filter according to claim 9, characterised in that The inner diameter of the first-level water guide pipe (214) is greater than that of the second-level water guide pipe (224), the inner diameter of the second-level water guide pipe (224) is greater than that of the third-level water guide pipe (234), and the inner diameters of the third-level water guide pipe (234), the fourth-level water guide pipe (244), the water outlet pipe (310) and the drainage port (320) are equal.

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