Seepage water purification system and control method

Abstract

The invention relates to the technical field of sewage treatment, in particular to a seepage water purification system and a control method. The system comprises a sewage temporary storage pool, a three-stage seepage water purification planting unit, a disinfection pool and a reuse water temporary storage pool which are connected in series in the water flow direction. Wherein each of the first seepage water purification planting unit, the second seepage water purification planting unit and the third seepage water purification planting unit comprises a water outlet layer, a transition layer, a functional soil layer and a plough layer, and the first seepage water purification planting unit and the second seepage water purification planting unit are provided with ventilation layers and are inoculated with heterotrophic aerobic bacteria and nitrifying bacteria respectively. The third seepage water purification planting unit is inoculated with denitrifying bacteria. The ventilation layer comprises ventilation discs which are distributed in an array mode, the hole diameters of concentric annular ventilation rings of the ventilation discs are gradually increased from inside to outside, ventilation holes incline outwards by 15-45 degrees, and radial uniform air distribution is achieved. The problem that traditional aeration is uneven is solved through the aperture gradient design, organic matter and nitrogen are separated and degraded through staged flora, COD, ammonia nitrogen and total phosphorus in sewage are removed in a gradient mode, and sewage can be recycled.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sewage treatment, in particular to a seepage water purification system and a control method. BACKGROUND

[0002] With the rapid development of environmental protection, people's understanding of the ecological function of wetlands is deepening. As the kidney of the earth, wetlands bear the key function of natural water purification and water quality improvement. However, during the process of urban development, the area of natural wetlands gradually shrinks or even disappears. Artificial wetlands have gained widespread attention and rapid development due to their unique advantages. Artificial wetland water purification technology is a new ecological sewage treatment method. Its basic principle is to plant specific wetland plants on the filler of artificial wetlands, and then build an artificial wetland ecosystem. When sewage flows through the wetland system, pollutants and nutrients are adsorbed, absorbed or decomposed by the system, achieving water purification.

[0003] In the application of existing aerobic treatment technology, uneven aeration and dissolved oxygen fluctuation are the core bottleneck of restricting treatment efficiency. Due to the uniform pore size and sparse gas distribution points of traditional aeration devices, it is easy to cause uneven gas diffusion, local area dissolved oxygen supersaturation and remote area anoxia, forming a significant dissolved oxygen concentration gradient and a wide dissolved oxygen concentration fluctuation amplitude. Under high load conditions, anoxic environment inhibits the activity of aerobic microorganisms, reduces the COD degradation rate and ammonia nitrogen nitrification efficiency; when the load is low, excessive aeration not only causes energy waste, but also inhibits the metabolism of denitrifying bacteria, resulting in large fluctuations in nitrogen removal rate. The above problems limit the metabolic function of microorganisms, resulting in low pollutant removal efficiency, which cannot meet the requirements of sewage reuse standards. SUMMARY

[0004] One of the purposes of the present application is to avoid the shortcomings of the prior art and provide a seepage water purification system. The seepage water purification system can realize uniform diffusion of gas and precise control of dissolved oxygen by using an array layout design of aeration discs and a gradient pore size design of aeration holes, effectively solve the problems of uneven aeration and dissolved oxygen fluctuation, and remove COD, ammonia nitrogen and total phosphorus in sewage by gradient through the series inoculation of heterotrophic aerobic bacteria, nitrifying bacteria and denitrifying bacteria in the three seepage water purification planting units, realizing the recycling of sewage.

[0005] The second purpose of the present application is to provide a control method for the seepage water purification system, which can dynamically adjust the hydraulic retention time and aeration opening and closing time of each unit, realize precise control of dissolved oxygen, and solve the imbalance problem between aerobic and anaerobic environments in traditional artificial wetlands.

[0006] One of the purposes of the present application is achieved by the following technical solutions: The application provides a percolation water purification system, which comprises, in sequence along a water flow direction, a sewage temporary storage pool, a first percolation water purification planting unit, a second percolation water purification planting unit, a third percolation water purification planting unit, a disinfection pool and a recycled water temporary storage pool; The first percolation water purification planting unit is inoculated with heterotrophic aerobic bacteria, the second percolation water purification planting unit is inoculated with nitrifying bacteria, and the third percolation water purification planting unit is inoculated with denitrifying bacteria; The first percolation water purification planting unit, the second percolation water purification planting unit and the third percolation water purification planting unit each comprise, in sequence from bottom to top, a water outlet layer, a transition layer, a functional soil layer and a plough layer, and a water-permeable filter cloth is arranged between adjacent layers; the water outlet layer is provided with a water outlet, and the plough layer is used for planting plants; The first percolation water purification planting unit and the second percolation water purification planting unit further comprise an aeration layer arranged between the transition layer and the functional soil layer, the aeration layer comprises a plurality of arrayed aeration discs, adjacent aeration discs are provided with gaps for gas flow, the center of each aeration disc is provided with an interface for connecting a gas source system, and the interfaces of the aeration discs are connected to the gas source system through a gas source distributor; The aeration disc is provided with a plurality of concentric aeration rings, each aeration ring is composed of a plurality of aeration holes, and the aeration hole diameters of the aeration rings from inside to outside gradually increase, so as to reduce the central gas flow resistance and realize radial uniform gas distribution.

[0007] In some embodiments, the aeration hole axis of the aeration disc forms an angle of 15°-45° with the plane where the aeration disc is located, and the aeration hole inclination directions of the aeration rings from inside to outside are all towards the side away from the center of the aeration disc.

[0008] In some embodiments, the functional soil layer is sequentially arranged from bottom to top with a lower soil mixture layer, a lower water passage layer, an upper soil mixture layer and an upper water passage layer; The transition layer is mixed by quartz sand, steel slag and foamed glass in a mass ratio of 5:3:2; The lower water passage layer and the upper water passage layer are mixed by zeolite, volcanic rock and ceramsite in a mass ratio of 4:3:3; The lower soil mixture layer and the upper soil mixture layer are mixed by soil, sand, wood chips and biochar in a mass ratio of 6:2:1:1; The water outlet layer is mixed by gravel and quartz sand in a mass ratio of 1:1; The plough layer is mixed by coarse sand and undisturbed soil in a mass ratio of 1:2.

[0009] In some embodiments, the gas source system comprises a controller, an air compressor, a first gas storage tank and a second gas storage tank; The air compressor, the first gas storage tank and the second gas storage tank are sequentially communicated through pipelines, an air inlet valve is arranged between the first gas storage tank and the second gas storage tank, the second gas storage tank is connected to the aeration layer of the first seepage water purification planting unit through a first air valve and connected to the aeration layer of the second seepage water purification planting unit through a second air valve; The second gas storage tank is further provided with a pressure stabilizing valve and a pressure regulating valve, and the first gas storage tank and the second gas storage tank are both provided with a pressure gauge and a safety pressure relief valve. The controller is electrically connected with the air compressor, the pressure gauge, the air inlet valve, the first air valve and the second air valve, so as to control the start and stop of the air compressor according to the pressure of the first gas storage tank and control the on-off of the air inlet valve according to the pressure of the second gas storage tank.

[0010] In some embodiments, a dissolved oxygen sensor is arranged in each of the first seepage water purification planting unit and the second seepage water purification planting unit, and the controller controls the opening time and the closing time of the first air valve and the second air valve according to the dissolved oxygen concentration data detected by the dissolved oxygen sensor.

[0011] In some embodiments, the heterotrophic aerobic bacteria include Bacillus subtilis and / or Pseudomonas putida, the nitrifying bacteria include Nitrosomonas and / or Nitrobacter, and the denitrifying bacteria include Paracoccus denitrificans and / or Pseudomonas stutzeri.

[0012] In some embodiments, the sewage temporary storage tank is connected to the water inlet end of the first seepage water purification planting unit through a first lifting pump, the water outlet of the first seepage water purification planting unit is connected to the water inlet end of the second seepage water purification planting unit through a second lifting pump, the water outlet of the second seepage water purification planting unit is connected to the water inlet end of the third seepage water purification planting unit through a third lifting pump, and the water outlet of the third seepage water purification planting unit is connected to the disinfection tank through a fourth lifting pump and a purification pipeline. The purification pipeline is detachably filled with a porous adsorption composite material, and the disinfection tank is provided with a chlorine disinfection system.

[0013] In some embodiments, the porous adsorption composite material is made of waste glass powder, the porous carrier is loaded with iron or its oxide, calcium oxide and magnesium oxide, the loading amount of the iron or its oxide is 5%-10% of the mass of the waste glass powder, the loading amount of the calcium oxide is 3%-5% of the mass of the waste glass powder, and the loading amount of the magnesium oxide is 2%-4% of the mass of the waste glass powder.

[0014] The second purpose of the present application is achieved by the following technical scheme: The present application provides a control method applied to the seepage water purification system, comprising the following steps: (1) Start the first booster pump, and pump the sewage in the sewage temporary storage pool into the first seepage water purification planting unit according to the preset flow rate; (2) The dissolved oxygen concentration is monitored through the dissolved oxygen sensor in the first seepage water purification planting unit, and the controller adjusts the opening and closing time length of the first aeration valve to maintain the dissolved oxygen concentration at 2 mg / L to 4 mg / L; (3) When the hydraulic retention time of the first seepage water purification planting unit reaches the preset value, the second booster pump is started to pump the sewage into the second seepage water purification planting unit; at the same time, the data of the dissolved oxygen sensor in the second seepage water purification planting unit is monitored to adjust the opening and closing time length of the second aeration valve to maintain the dissolved oxygen concentration at 1.5 mg / L to 3 mg / L; (4) When the hydraulic retention time of the second seepage water purification planting unit reaches the preset value, the third booster pump is started to pump the sewage into the third seepage water purification planting unit; (5) The fourth booster pump is started to send the water treated by the third seepage water purification planting unit into the disinfection pool, and the purified water after disinfection is transported to the reuse water temporary storage pool for storage.

[0015] In some embodiments, the step of dynamically adjusting the treatment parameters based on the water quality of the inlet water is further included: a) The COD online sensor and the ammonia nitrogen online sensor are arranged in the sewage temporary storage pool to monitor the COD concentration and the ammonia nitrogen concentration of the inlet water in real time; b) When the COD concentration is greater than the preset threshold value, the hydraulic retention time of the first seepage water purification planting unit is extended to 1.2-1.5 times of the preset value, and the opening time length of the first aeration valve is increased to maintain the dissolved oxygen concentration at 3-4 mg / L; c) When the ammonia nitrogen concentration is greater than the preset threshold value, the hydraulic retention time of the second seepage water purification planting unit is extended to 1.2-1.5 times of the preset value, and the opening time length of the second aeration valve is increased to maintain the dissolved oxygen concentration at 2-3 mg / L; d) When the COD and ammonia nitrogen concentrations are both less than or equal to the preset threshold value, the controller automatically restores the default parameters of each unit.

[0016] Compared with the prior art, the technical scheme provided by the present application can include the following beneficial effects: (1) The aeration disc designed in an array layout and the aeration hole designed in a gradient aperture can solve the problem of uneven aeration of the traditional aeration device, and the inclined aeration hole of the aeration disc can enhance the uniformity of gas diffusion, avoid local oxygen saturation or oxygen deficiency, effectively stabilize the dissolved oxygen in the concentration range required by the microbial flora, thereby improving the activity of aerobic microorganisms, and improving the COD degradation rate and the ammonia nitrogen nitrification efficiency.

[0017] (2) The three-stage series flow seepage water purification planting unit, wherein the first flow seepage water purification planting unit is inoculated with heterotrophic aerobic bacteria, the second flow seepage water purification planting unit is inoculated with nitrifying bacteria, and the third flow seepage water purification planting unit is inoculated with denitrifying bacteria, in combination with a multi-layer seepage substrate, solves the problem of unstable treatment effect caused by water quality fluctuation in traditional wetlands.

[0018] (3) Through intelligent dynamic regulation and control, manual intervention can be reduced, operation and maintenance costs can be reduced, and the effluent after treatment can be directly used for flushing toilets, landscaping and other recycling scenarios, realizing the trinity function of water purification, recycling and landscape. BRIEF DESCRIPTION OF DRAWINGS

[0019] The above and other objects, features and advantages of the present application will become more apparent from the following detailed description of preferred embodiments of the present application taken in conjunction with the accompanying drawings, in which like reference characters refer to the like parts throughout the different views.

[0020] Fig. 1 is a structural schematic diagram of a flow seepage water purification system shown in an embodiment of the present application; Fig. 2 is a structural schematic diagram of a first flow seepage water purification planting unit shown in an embodiment of the present application; Fig. 3 is a structural schematic diagram of an aeration layer shown in an embodiment of the present application.

[0021] In the drawings: 1, sewage temporary storage tank; 2, first flow seepage water purification planting unit; 20, pit; 21, effluent layer; 22, transition layer; 23, functional soil layer; 231, lower soil mixing layer; 232, lower water passage layer; 233, upper soil mixing layer; 234, upper water passage layer; 24, tillage layer; 25, aeration layer; 251, aeration disc; 3, second flow seepage water purification planting unit; 4, third flow seepage water purification planting unit; 5, disinfection tank; 6, recycled water temporary storage tank; 7, air supply system. DETAILED DESCRIPTION

[0022] The preferred embodiments of the present application will be described in more detail below with reference to the accompanying drawings. Although the preferred embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to make the present application more thorough and complete, and to fully convey the scope of the present application to those skilled in the art.

[0023] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting. As used in this application and the appended claims, the singular forms "a," "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that the term "and / or," as used herein, refers to and encompasses any and all possible combinations of one or more of the associated listed items.

[0024] It should be understood that although the terms "first," "second," "third," etc. can be used in this application to describe various information, the information should not be limited to these terms. These terms are only used to distinguish one type of information from another type of information. For example, the first information can also be referred to as the second information without departing from the scope of the application, and similarly, the second information can also be referred to as the first information. Thus, the features defined with "first," "second" can explicitly or implicitly include one or more of the features. In the description of the application, the meaning of "multiple" is two or more, unless otherwise specifically limited.

[0025] In the prior art, the constructed wetland water purification technology realizes sewage purification by constructing an ecological system through fillers and plants. The traditional aeration device causes large differences in dissolved oxygen distribution due to uneven gas distribution. Local anoxia inhibits microbial activity at high load, and excessive aeration causes energy waste at low load, making it difficult to stabilize the treatment efficiency to meet the standard. For example, in the scenario of urban sewage treatment, the water quality fluctuates frequently, and the traditional method cannot adapt to the load change, resulting in significant fluctuations in COD and ammonia nitrogen removal rate.

[0026] To solve the above problems, the present application provides a seepage water purification system, which can realize uniform diffusion of gas and precise control of dissolved oxygen through the array layout design of the aeration disc 251 and the gradient aperture design of the aeration hole, effectively solve the problems of uneven aeration and dissolved oxygen fluctuation, and simultaneously realize gradient removal of COD, ammonia nitrogen and total phosphorus in sewage through the series inoculation of heterotrophic aerobic bacteria, nitrifying bacteria and denitrifying bacteria in the three-stage seepage water purification planting unit, and realize the recycling of sewage.

[0027] The technical solutions of the embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0028] Referring to Figs. 1 to 3 The present application provides a seepage water purification system, which comprises a sewage temporary storage tank 1, a first seepage water purification planting unit 2, a second seepage water purification planting unit 3, a third seepage water purification planting unit 4, a disinfection tank 5 and a recycled water temporary storage tank 6 connected in series through pipes and valves in the water flow direction.

[0029] The seepage water purification system can realize sewage transmission by gravity flow or lifting pump. The sewage temporary storage tank 1, the first seepage water purification planting unit 2, the second seepage water purification planting unit 3, the third seepage water purification planting unit 4, the disinfection tank 5 and the recycled water temporary storage tank 6 are all reinforced concrete tank structures, wherein the sewage temporary storage tank 1 is used for storing sewage to be treated and adjusting the inflow, and the effective volume is determined according to the designed water quantity; the disinfection tank 5 and the recycled water temporary storage tank 6 realize sterilization and water purification storage respectively, and the recycled water temporary storage tank 6 realizes toilet water or green irrigation through an external delivery system.

[0030] The first seepage water purification planting unit 2, the second seepage water purification planting unit 3 and the third seepage water purification planting unit 4 provided by the present application are used to realize the structure of sewage treatment. After digging the pit 20 on the ground, the water outlet layer 21, the transition layer 22, the functional soil layer 23 and the plough layer 24 can be laid in turn from bottom to top, and the water-permeable filter cloth is laid between adjacent layers to realize water quality purification through the synergistic effect of physical filtration and biological degradation. Exemplarily, the first, second and third seepage water purification planting units 4 are steel-concrete structures with a length of 9.6 m, a width of 4.0 m and a depth of 1.4 m, and the effective depth is 1.1 m. Among them, the thickness of the water outlet layer 21 can be 10 cm, and gravel or pebbles with a particle size of 20-50 mm are used, and the bottom is provided with a water outlet to connect the next unit; the thickness of the transition layer 22 can be 10 cm, which is composed of quartz sand, steel slag and foamed glass, and is used to intercept suspended solids (SS) and colloidal impurities; the thickness of the functional soil layer 23 can be 60 cm, which is the core area of microbial attachment and pollutant degradation. In some embodiments, multiple purification seepage layers can be provided, for example, from top to bottom, the upper soil mixed layer 233 with a thickness of 20 cm, the upper water passage layer 234 with a thickness of 10 cm, the lower soil mixed layer 231 with a thickness of 20 cm and the lower water passage layer 232 with a thickness of 20 cm. The thickness of the plough layer 24 can be 20 cm, and wetland plants such as reeds and cattails are planted, and the root system of the plants can promote microbial metabolism. After the system runs for a period of time, the plants can be harvested and each unit can be cleaned and maintained.

[0031] To strengthen the efficiency of aerobic degradation, the first seepage water purification planting unit 2 and the second seepage water purification planting unit 3 are additionally provided with a ventilation layer 25 between the transition layer 22 and the functional soil layer 23, the ventilation layer 25 is used to improve the dissolved oxygen concentration of the two, and is composed of a plurality of arrayed ventilation discs 251, the size specification of which can be adjusted according to actual needs, for example, the thickness is set to 3 cm, and the shape is selected to be circular or regular hexagonal. A sewage flow gap is reserved between adjacent ventilation discs 251, and the disc body is fixed on the concrete beam on the inner wall of the pit 20 through a PVC support frame. A gas source interface is arranged at the center of the disc body, and the ventilation disc 251 is sealingly connected to the gas source system 7 through the quick plug joint of the gas source distributor and the raw material belt. The ventilation disc 251 is provided with three concentric annular ventilation rings, and the distance of each concentric annular ventilation ring from the center can be determined according to the size of the ventilation disc 251. At the same time, in order to ensure that each annular ventilation ring has a consistent air output, the hole diameters of each ring are increased from inside to outside, so as to reduce the central airflow resistance and ensure the uniform radial air output. In specific implementation, the number and diameter of the holes can be adjusted according to actual needs, as long as the air output of each ring is consistent.

[0032] In the embodiment, when the system is running, the sewage in the sewage temporary storage tank 1 enters the seepage water purification planting units in turn. In the first seepage water purification planting unit 2, the heterotrophic aerobic bacteria degrade organic matter in the functional soil layer 23, and the ventilation layer 25 uniformly supplies oxygen through the annular ventilation rings to maintain an aerobic environment; in the second seepage water purification planting unit 3, the nitrifying bacteria convert ammonia nitrogen into nitrate, and the ventilation layer 25 adjusts the dissolved oxygen to a suitable concentration; in the third seepage water purification planting unit 4, the denitrifying bacteria reduce the nitrate to nitrogen under anoxic conditions, and the functional soil layer 23 provides a carbon source to promote the denitrification reaction; after treatment, the water flows through the disinfection tank 5 to be chlorinated and sterilized, and is finally stored in the reclaimed water temporary storage tank 6.

[0033] Through the above technical solution, the application realizes layered and collaborative sewage purification, realizes integrated treatment of organic matter degradation, nitrogen conversion and suspended matter removal through the synergistic effect of the plants in the tillage layer 24, the microorganisms in the functional soil layer 23 and the filtration of the transition layer 22. The aperture gradient and inclined hole structure of the ventilation disc 251 solve the problems of large central airflow resistance and uneven gas distribution of traditional aeration devices, and improve the efficiency of aerobic reaction.

[0034] To further balance the dissolved oxygen concentration of the first seepage water purification planting unit 2 and the second seepage water purification planting unit, and ensure the uniformity of aeration, on the basis of the above specific embodiment, the angle and direction of the air holes are optimized, specifically, the air hole axis and the plane where the air disc 251 is located form an angle of 15°-45°, and the inclined direction of the air holes of the annular air ring from inside to outside is towards the side away from the disc center. Under this setting, the inclined hole channel makes the airflow obtain vertical upward lifting component velocity and horizontal tangential component velocity along the disc surface, and the tangential component velocity of multiple annular holes superimposes to form a cyclone effect, promoting the uniform radial diffusion of the gas; the uniform outward inclined direction can avoid the air flow of adjacent annular rings from colliding, and at the same time prevent local blockage in the center area caused by airflow interference, and cooperates with the reduction of the hole diameter gradient to reduce the center airflow resistance, thereby improving the radial air distribution uniformity of the aeration layer 25.

[0035] Further, the functional soil layer 23 is sequentially laid from bottom to top with a lower soil mixture layer 231, a lower water passage layer 232, an upper soil mixture layer 233, and an upper water passage layer 234; The transition layer 22 is mixed by quartz sand, steel slag, and foamed glass in a mass ratio of 5:3:2; The lower water passage layer 232 and the upper water passage layer 234 are mixed by zeolite, volcanic rock, and ceramic ball in a mass ratio of 4:3:3; The lower soil mixture layer 231 and the upper soil mixture layer 233 are mixed by soil, sand, wood chips, and biochar in a mass ratio of 6:2:1:1; The water outlet layer 21 is mixed by gravel and quartz sand in a mass ratio of 1:1; The tillage layer 24 is mixed by coarse sand and undisturbed soil in a mass ratio of 1:2.

[0036] In this embodiment, the functional soil layer 23 is used for microbial attachment carriers and pollutant degradation core areas, and is specifically designed in layers, the lower soil mixture layer 231 and the upper soil mixture layer 233 increase the organic matter content by adding wood chips and biochar, providing a carbon source for microbial metabolism, and the addition of sand improves the air permeability. The lower water passage layer 232 and the upper water passage layer 234 simultaneously guide water and adsorb heavy metals and suspended solids through the synergistic effect of zeolite, volcanic rock, and ceramic ball. The alkaline components of the steel slag in the transition layer 22 can neutralize the acidity of the wastewater, and the foamed glass enhances the ability to intercept impurities. The combination of gravel and quartz sand in the water outlet layer 21 forms a stable support structure to prevent bottom sedimentation. The tillage layer 24 is optimized by the ratio of coarse sand and undisturbed soil, which not only ensures the nutrients needed for plant growth, but also avoids root rot caused by insufficient water permeability.

[0037] Further, the gas source system 7 includes a controller, an air compressor, a first gas storage tank, and a second gas storage tank; The air compressor, the first gas storage tank and the second gas storage tank are communicated in sequence through pipelines, the first gas storage tank and the second gas storage tank are provided with an air inlet valve, the second gas storage tank is communicated with the aeration layer 25 of the first seepage water purification planting unit 2 through a first aeration valve and with the aeration layer 25 of the second seepage water purification planting unit 3 through a second aeration valve; The second gas storage tank and the aeration layer 25 are further provided with a pressure stabilizing valve and a pressure regulating valve, and the first gas storage tank and the second gas storage tank are both provided with a pressure gauge and a safety pressure relief valve; The controller is electrically connected with the air compressor, the pressure gauge, the air inlet valve, the first aeration valve and the second aeration valve respectively, so as to control the start and stop of the air compressor according to the pressure of the first gas storage tank and control the on-off of the air inlet valve according to the pressure of the second gas storage tank. The air compressor delivers compressed air to the first gas storage tank, when the pressure of the first gas storage tank reaches the set upper limit, the controller stops the air compressor from running; when the pressure is lower than the lower limit, the air compressor is restarted. The first gas storage tank supplements gas to the second gas storage tank through the air inlet valve, and the controller adjusts the opening degree of the air inlet valve according to the pressure of the second gas storage tank. The gas output by the second gas storage tank is stabilized by the pressure stabilizing valve to eliminate pressure fluctuation, and then the output pressure is accurately controlled by the pressure regulating valve, and then the gas is supplied to the aeration layer 25 of the two planting units through the first aeration valve and the second aeration valve respectively. The safety pressure relief valve is automatically opened when the gas storage tank is overpressure, so as to ensure the safe operation of the system. Exemplarily, the rated power of the air compressor can be selected as 5kW, the exhaust volume is 0.3m 3 / min, and the outlet pressure is 1MPa; the volume of the first gas storage tank can be selected as 5m 3 , and the pressure control range is 0.8-1MPa; the volume of the second gas storage tank is 5m 3 , the pressure is controlled at 0.5MPa, and the outlet pressure is stabilized to 0.05MPa by the pressure regulating valve, which is suitable for the low-pressure and large-flow gas supply requirement of the aeration layer 25 and the water depth pressure where the aeration layer 25 is located.

[0038] Further, the first and second percolation water purification planting units 2 and 3 are each provided with a dissolved oxygen sensor, and the controller controls the opening and closing time of the first and second aeration valves according to the dissolved oxygen concentration data detected by the dissolved oxygen sensor. The dissolved oxygen sensor is installed in the functional soil layer 23 or the water outlet layer 21 of the percolation water purification planting unit to collect the dissolved oxygen concentration data of the water body in real time and transmit the data to the controller. When the dissolved oxygen concentration is lower than the set lower limit, the controller increases the opening time of the corresponding aeration valve, and prolongs the oxygen supply time of the air supply system 7 to increase the oxygen input; when the dissolved oxygen concentration is higher than the set upper limit, the controller shortens the opening time of the aeration valve or closes the valve to reduce the oxygen input to avoid excessive aeration. By dynamically adjusting the working cycle of the aeration valve, the dissolved oxygen concentration can be stabilized within the target range. For example, the first aeration valve of the first percolation water purification planting unit 2 adopts duty cycle control, and the default opening time is 30 min per cycle. When the dissolved oxygen sensor detects that DO < 2 mg / L, the opening time is extended to 45 min per cycle. The opening time of the second aeration valve of the second percolation water purification planting unit 3 is 20 min per cycle, and the target dissolved oxygen is 1.5-3 mg / L. When DO > 3 mg / L, the opening time is shortened to 15 min per cycle.

[0039] Further, the heterotrophic aerobic bacteria include Bacillus subtilis and / or Pseudomonas putida; the nitrifying bacteria include Nitrosomonas and / or Nitrobacter; and the denitrifying bacteria include Paracoccus denitrificans and / or Pseudomonas stutzeri.

[0040] During construction, the fillers of the water outlet layer 21, the transition layer 22, the functional soil layer 23, and the plough layer 24 are first flushed out, and then laid according to the design requirements. The functional soil layer 23 can be inoculated. Specifically, the heterotrophic aerobic bacteria of the first percolation water purification planting unit 2 are loaded on polyurethane sponge carriers with a pore size of 500-800 pm. Bacillus subtilis and Pseudomonas putida can be loaded separately or mixed. In some embodiments, to ensure biological activity and survival rate, Bacillus subtilis and Pseudomonas putida are mixed at a ratio of 1:1, and the inoculation amount can be set to 10 8 CFU / g dry soil. At the same time, the polyurethane sponge carrier accounts for 10% of the mass of the functional soil layer 23. The nitrifying bacteria of the second percolation water purification planting unit 3 can be loaded on activated carbon particles with a particle size of 3-5 mm. Nitrosomonas and Nitrobacter can be loaded separately or mixed. In some embodiments, Nitrosomonas and Nitrobacter are mixed at a ratio of 2:1, and the inoculation amount can be set to 5 7CFU / g dry soil, while the activated carbon granular carrier accounts for 5% of the mass of the functional soil layer 23. The denitrifying bacteria of the third seepage water purification planting unit 4 can be loaded alone or mixed with Paracoccus denitrificans and Pseudomonas stutzeri. In some embodiments, the Paracoccus denitrificans and Pseudomonas stutzeri are mixed at a ratio of 3:2, and the inoculation amount is 8 x 10 7 CFU / g dry soil, while the activated carbon granular carrier accounts for 5% of the mass of the functional soil layer 23. The denitrifying bacteria of the third seepage water purification planting unit 4 can be loaded alone or mixed with Paracoccus denitrificans and Pseudomonas stutzeri. In some embodiments, the Paracoccus denitrificans and Pseudomonas stutzeri are mixed at a ratio of 3:2, and the inoculation amount is 8 x 10

[0041] After the inoculation is completed, domestication work is performed, and the specific process is as follows: Low-load water is fed on the first day and the second day, for example, the water fed is 50% of the design flow rate, and the dissolved oxygen is monitored to be stable at 2-4 mg / L; The design flow rate is gradually increased on the third day to the fifth day, and the COD and ammonia nitrogen of the effluent are detected every day, and when the COD is less than or equal to 40 mg / L and the ammonia nitrogen removal rate is greater than or equal to 50%, it is determined that the domestication is completed; Stable operation is performed on the sixth day to the seventh day, and the opening time of the aeration valve is adjusted to a dissolved oxygen fluctuation of less than or equal to 0.5 mg / L.

[0042] Further, the sewage temporary storage tank 1 is connected to the water inlet end of the first seepage water purification planting unit 2 through a first lifting pump, the water outlet of the first seepage water purification planting unit 2 is connected to the water inlet end of the second seepage water purification planting unit 3 through a second lifting pump, the water outlet of the second seepage water purification planting unit 3 is connected to the water inlet end of the third seepage water purification planting unit 4 through a third lifting pump, and the water outlet of the third seepage water purification planting unit 4 is connected to the disinfection tank 5 through a fourth lifting pump and a purification pipeline; The purification pipeline is detachably filled with a porous adsorption composite material, and the disinfection tank 5 is provided with a chlorine disinfection system.

[0043] In this embodiment, after the sewage is treated by the three seepage planting units, it enters the purification pipeline through the fourth lifting pump. The detachable porous adsorption composite material filled in the pipeline can capture the residual small particles in the water body, and further remove heavy metal and phosphate pollutants through ion exchange reactions with metal oxides and calcium-magnesium compounds loaded on the surface. After the water body treated by adsorption enters the disinfection tank 5, the chlorine disinfection system automatically adjusts the disinfectant dosage according to the flow rate to inactivate pathogenic microorganisms. The porous adsorption composite material is designed in a modular manner, which can be conveniently replaced when saturated to avoid the increase of system operating pressure caused by material blockage. The step-by-step configuration of the lifting pump forms independent hydraulic control units for each treatment unit, which can flexibly adjust the pumping rate according to the water load to ensure that each unit operates at the optimal hydraulic retention time.

[0044] Further, the porous adsorption composite material is made of waste glass powder, and the porous carrier is formed by foaming. The porous carrier is loaded with iron or its oxide, calcium oxide and magnesium oxide. The loading amount of the iron or its oxide is 5%-10% of the mass of the waste glass powder. The loading amount of the calcium oxide is 3%-5% of the mass of the waste glass powder. The loading amount of the magnesium oxide is 2%-4% of the mass of the waste glass powder.

[0045] In the embodiment, the porous carrier forms a three-dimensional through-pore structure through a foaming process, and forms a tortuous path to prolong the contact time when the water flow passes through the purification pipeline. The iron oxide, the calcium oxide and the magnesium oxide form composite active sites on the surface of the carrier. The iron oxide adsorbs heavy metal ions through coordination. The calcium oxide reacts with phosphate ions to generate hydroxyapatite precipitate. The magnesium oxide is combined with organic matter through hydrogen bonds. In some embodiments, the porosity of the porous carrier is 60%-70%, the specific surface area is 50-80 m 2 / g, and the average pore size is 50-100 μm. When the water flow passes through the purification pipeline filled with the material, the pollutants are adsorbed and chemically fixed in multiple stages. For example, the heavy metal ions are captured by the iron oxide, the phosphates react with the calcium oxide to generate precipitate, and the organic matter is adsorbed and degraded by the magnesium oxide. After the material is saturated, the whole material can be taken out for regeneration treatment, thereby avoiding the problem of pipeline blockage caused by traditional adsorbents.

[0046] The application further provides a control method of the percolation water purification system, which comprises the following steps: (1) starting the first lifting pump to pump the sewage in the sewage temporary storage tank 1 into the first percolation water purification planting unit 2 at a preset flow rate; (2) monitoring the dissolved oxygen concentration through the dissolved oxygen sensor in the first percolation water purification planting unit 2, and adjusting the opening and closing time of the first aeration valve by the controller to maintain the dissolved oxygen concentration at 2 mg / L to 4 mg / L; (3) when the hydraulic retention time of the first percolation water purification planting unit 2 reaches a preset value, starting the second lifting pump to pump the sewage into the second percolation water purification planting unit 3; simultaneously monitoring the data through the dissolved oxygen sensor in the second percolation water purification planting unit 3, and adjusting the opening and closing time of the second aeration valve to maintain the dissolved oxygen concentration at 1.5 mg / L to 3 mg / L; (4) when the hydraulic retention time of the second percolation water purification planting unit 3 reaches a preset value, starting the third lifting pump to pump the sewage into the third percolation water purification planting unit 4; (5) starting the fourth lifting pump to send the water treated by the third percolation water purification planting unit 4 into the disinfection tank 5, and sending the disinfected purified water to the recycled water temporary storage tank 6 for storage.

[0047] In the present embodiment, sewage flows through three series of seepage planting units in turn through multi-stage lifting pumps, each unit is monitored in real time by a dissolved oxygen sensor, and the controller automatically adjusts the opening and closing time of the corresponding aeration valve according to the set threshold value. When the COD concentration is detected to be excessive, the system automatically prolongs the treatment time of the first unit and increases the aeration intensity to strengthen the organic matter degradation capacity of heterotrophic bacteria; when the ammonia nitrogen concentration is detected to be excessive, the treatment time of the second unit is prolonged and the aeration strategy is optimized to promote the ammonia oxidation of nitrifying bacteria. The treated water is disinfected and then enters the reuse storage, and the whole process realizes parameter optimization through online monitoring and automatic control. Exemplarily, the hydraulic time of the first seepage water purification planting unit 2 can be set to 6h, the hydraulic time of the second seepage water purification planting unit 3 can be set to 6h, and the hydraulic time of the third seepage water purification planting unit 4 can be set to 10h.

[0048] In some specific embodiments, the COD online sensor can adopt a UV absorption detection module, and the ammonia nitrogen sensor can adopt an ion selective electrode detection module. The detection data is transmitted wirelessly to the controller. The lifting pump can be an intelligent pump with a flow meter, and the rotation speed is linked to the liquid level of the treatment unit. The calculation of hydraulic retention time can be dynamically corrected by combining the volume of the treatment unit and the instantaneous flow.

[0049] Further, the control method further comprises the step of dynamically adjusting the treatment parameters based on the water quality: a) setting a COD online sensor and an ammonia nitrogen online sensor in the sewage temporary storage tank 1 to monitor the COD concentration and ammonia nitrogen concentration of the influent in real time; b) when the COD concentration > the preset threshold value, the hydraulic retention time of the first seepage water purification planting unit 2 is prolonged to 1.2-1.5 times of the preset value, the opening time of the first aeration valve is increased, and the dissolved oxygen concentration is maintained at 3-4 mg / L; c) when the ammonia nitrogen concentration > the preset threshold value, the hydraulic retention time of the second seepage water purification planting unit 3 is prolonged to 1.2-1.5 times of the preset value, the opening time of the second aeration valve is increased, and the dissolved oxygen concentration is maintained at 2-3 mg / L; d) when the COD and ammonia nitrogen concentrations are both ≤ the preset threshold value, the controller automatically restores the default parameters of each unit.

[0050] Specifically, when the COD online sensor detects that the organic matter concentration exceeds the set value, the system automatically prolongs the first seepage unit processing time and increases the air valve opening time, so that the heterotrophic aerobic bacteria can obtain sufficient oxygen to accelerate the decomposition of organic matter. When the ammonia nitrogen concentration exceeds the standard, the system prolongs the second seepage unit processing time and enhances the aeration intensity, so as to promote the nitrifying bacteria to convert the ammonia nitrogen into nitrate. When the pollutant concentration falls below the threshold value, the controller automatically restores the initial operating parameters to avoid energy waste caused by excessive aeration. Through the linkage adjustment of dissolved oxygen concentration and hydraulic retention time, the dynamic matching of treatment intensity and influent load is realized.

[0051] The above has described various embodiments of the present application, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those skilled in the art without departing from the scope and spirit of the described embodiments. The selection of terms used herein is intended to best explain the principles, practical application or improvement of technology in the market of the embodiments, or to enable other ordinary skilled persons in the art to understand the embodiments disclosed herein.

Claims

1. A permeable water purification system, characterized in that, The sewage temporary storage tank, the first seepage water purification planting unit, the second seepage water purification planting unit, the third seepage water purification planting unit, the disinfection tank and the recycled water temporary storage tank are sequentially connected in series along the water flow direction. The first seepage water purification planting unit is inoculated with heterotrophic aerobic bacteria, the second seepage water purification planting unit is inoculated with nitrifying bacteria, and the third seepage water purification planting unit is inoculated with denitrifying bacteria. The first seepage water purification planting unit, the second seepage water purification planting unit and the third seepage water purification planting unit each comprise, from bottom to top, a water outlet layer, a transition layer, a functional soil layer and a plough layer, which are sequentially laid in a pit, and a water permeable filter cloth is laid between adjacent layers. The first seepage water purification planting unit and the second seepage water purification planting unit each further comprise an aeration layer laid between the transition layer and the functional soil layer, the aeration layer comprising a plurality of aeration discs arranged in an array, adjacent aeration discs having a gap for gas flow, and the center of each aeration disc being provided with an interface for connecting to a gas source system, and the interfaces of the aeration discs being connected to the gas source system through a gas source distributor. The aeration disc is provided with a plurality of concentric annular aeration rings, each annular aeration ring being composed of a plurality of aeration holes, and the aeration hole diameters of the annular aeration rings from inside to outside gradually increase, so as to reduce the central airflow resistance and achieve radial uniform gas distribution.

2. The percolating water purification system of claim 1, wherein The aeration hole axis of the aeration disc forms an angle of 15°-45° with the plane in which the aeration disc lies, and the aeration hole inclination directions of the annular aeration rings from inside to outside are all towards the side away from the center of the aeration disc.

3. The percolating water purification system of claim 1, wherein, The functional soil layer is sequentially laid from bottom to top with a lower soil mixture layer, a lower water passage layer, an upper soil mixture layer and an upper water passage layer. The transition layer is mixed from quartz sand, steel slag and foamed glass in a mass ratio of 5:3:

2. The lower water passage layer and the upper water passage layer are mixed from zeolite, volcanic rock and ceramic ball in a mass ratio of 4:3:

3. The lower soil mixture layer and the upper soil mixture layer are mixed from soil, sand, wood chips and biochar in a mass ratio of 6:2:1:

1. The water outlet layer is mixed from gravel and quartz sand in a mass ratio of 1:

1. The plough layer is mixed from coarse sand and undisturbed soil in a mass ratio of 1:

2.

4. The percolating water purification system of claim 1, wherein The gas source system comprises a controller, an air compressor, a first gas storage tank and a second gas storage tank. The air compressor, the first gas storage tank and the second gas storage tank are sequentially connected through pipelines, an air inlet valve is arranged between the first gas storage tank and the second gas storage tank, the second gas storage tank is connected to the aeration layer of the first seepage water purification planting unit through a first aeration valve and connected to the aeration layer of the second seepage water purification planting unit through a second aeration valve. A pressure stabilizing valve and a pressure regulating valve are further arranged between the second gas storage tank and the aeration layer, and the first gas storage tank and the second gas storage tank are each provided with a pressure gauge and a safety pressure relief valve. The controller is electrically connected to the air compressor, the pressure gauge, the air inlet valve, the first aeration valve and the second aeration valve, so as to control the start and stop of the air compressor according to the pressure of the first gas storage tank and control the opening and closing of the air inlet valve according to the pressure of the second gas storage tank.

5. The percolation water purification system of claim 4, wherein The first and second seepage water purification planting units are provided with dissolved oxygen sensors, and the controller controls the opening and closing time of the first and second air valves according to the dissolved oxygen concentration data detected by the dissolved oxygen sensors.

6. The percolation water purification system of claim 1, wherein The heterotrophic aerobic bacteria include Bacillus subtilis and / or Pseudomonas putida; the nitrifying bacteria include Nitrosomonas and / or Nitrobacter; and the denitrifying bacteria include Paracoccus denitrificans and / or Pseudomonas stutzeri.

7. The percolation water purification system of claim 1, wherein The sewage temporary storage tank is connected with the water inlet end of the first seepage water purification planting unit through a first lifting pump, the water outlet of the first seepage water purification planting unit is connected with the water inlet end of the second seepage water purification planting unit through a second lifting pump, the water outlet of the second seepage water purification planting unit is connected with the water inlet end of the third seepage water purification planting unit through a third lifting pump, and the water outlet of the third seepage water purification planting unit is connected with the disinfection tank through a fourth lifting pump and a purification pipeline. The purification pipeline is detachably filled with porous adsorption composite material, and the disinfection tank is provided with a chlorine disinfection system.

8. The percolation water purification system of claim 7, wherein, The porous adsorption composite material is prepared by foaming waste glass powder into a porous carrier, and the porous carrier is loaded with iron or its oxide, calcium oxide and magnesium oxide, wherein the loading amount of the iron or its oxide is 5%-10% of the mass of the waste glass powder, the loading amount of the calcium oxide is 3%-5% of the mass of the waste glass powder, and the loading amount of the magnesium oxide is 2%-4% of the mass of the waste glass powder.

9. A control method of a seepage water purification system, applied to the seepage water purification system according to any one of claims 1-8, characterized in that, The method comprises the following steps: (1) Start the first lifting pump to pump the sewage in the sewage temporary storage tank into the first seepage water purification planting unit at a preset flow rate; (2) Monitor the dissolved oxygen concentration by the dissolved oxygen sensor in the first seepage water purification planting unit, and adjust the opening and closing time of the first air valve by the controller to maintain the dissolved oxygen concentration at 2 mg / L to 4 mg / L; (3) When the hydraulic retention time of the first seepage water purification planting unit reaches a preset value, start the second lifting pump to pump the sewage into the second seepage water purification planting unit; simultaneously monitor the data by the dissolved oxygen sensor in the second seepage water purification planting unit, and adjust the opening and closing time of the second air valve to maintain the dissolved oxygen concentration at 1.5 mg / L to 3 mg / L; (4) When the hydraulic retention time of the second seepage water purification planting unit reaches a preset value, start the third lifting pump to pump the sewage into the third seepage water purification planting unit; (5) Start the fourth lifting pump to send the treated water in the third seepage water purification planting unit into the disinfection tank, and send the disinfected purified water to the temporary storage tank for reuse.

10. The control method according to claim 9, characterized by, The method further comprises the following steps of dynamically adjusting the treatment parameters based on the water quality: a) Set a COD online sensor and an ammonia nitrogen online sensor in the sewage temporary storage tank to monitor the COD concentration and ammonia nitrogen concentration in real time; b) When the COD concentration is greater than a preset threshold, extend the hydraulic retention time of the first seepage water purification planting unit to 1.2-1.5 times of the preset value, increase the opening time of the first air valve, and maintain the dissolved oxygen concentration at 3-4 mg / L. c) When the ammonia nitrogen concentration > preset threshold value, the hydraulic retention time of the second percolation water purification planting unit is extended to 1.2-1.5 times of the preset value, the opening time of the second aeration valve is increased, and the dissolved oxygen concentration is maintained at 2-3 mg / L; d) When the COD and ammonia nitrogen concentration are both ≤ preset threshold value, the controller automatically restores the default parameters of each unit.

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