CN104150698B - A kind of apparatus and method of M type artificial swamp advanced treatment domestic sewage in rural areas - Google Patents

Abstract

A device for advanced treatment of rural domestic sewage in M-type constructed wetlands, mainly comprising: a first-level grille machine connected to a second-level grille machine; a second-level grille machine connected to an M-type constructed wetland; The pressure pump is connected to the surface turbulence screening device; the water outlet of the surface turbulence screening device is connected to the water outlet tank. The invention also discloses a method for the advanced treatment of rural domestic sewage by the M-shaped artificial wetland. The treatment effect is particularly obvious for sewage with high content of heavy metals and large fluctuations in water pollution load.

Description

A device and method for advanced treatment of rural domestic sewage in an M-shaped constructed wetland

technical field

The invention relates to a device for advanced treatment of rural domestic sewage in an M-shaped artificial wetland.

The invention also relates to a method for advanced treatment of tertiary effluent of sewage by using the above-mentioned device.

Background technique

Constructed wetland (CW · Constructed Wetland) sewage treatment technology is a new sewage treatment technology developed in the late 1970s. It has the characteristics of good treatment effect, strong nitrogen and phosphorus removal ability, convenient operation and maintenance management, low engineering infrastructure and operation costs, and strong adaptability to load changes. It is more suitable for small towns or villages with low technical management level and small scale. sewage treatment. Purification mechanism of constructed wetlands: The treatment of wastewater by constructed wetlands integrates the three functions of physics, chemistry and biology. After the wetland system matures, the surface of the filler and the root system of the plant will form a biofilm due to the growth of a large number of microorganisms. When the wastewater flows through the biofilm, a large amount of SS is blocked and intercepted by the filler and plant roots, and the organic pollutants are removed through the absorption, assimilation and dissimilation of the biofilm. In the wetland system, due to the transfer and release of oxygen by plant roots, the surrounding environment appears aerobic, anoxic, and anaerobic in sequence, ensuring that nitrogen and phosphorus in wastewater can not only be absorbed by plants and microorganisms as nutrients, but also can be absorbed by plants and microorganisms. It is removed through nitrification and denitrification, and finally the wetland system replaces the filler or harvests the planted plants to remove the pollutants.

The main problem of rural domestic sewage lies in its dispersed type, low pollution load and the characteristics of a small amount of sundries. This invention uses artificial wetland combined with surface turbulent flow screening device to treat rural domestic sewage, which provides a better solution for the ecological treatment of rural domestic sewage. Subsequent purification steps.

Contents of the invention

The purpose of the present invention is to provide an M-type constructed wetland device for advanced treatment of rural domestic sewage.

Another object of the present invention is to provide a method for advanced treatment of rural domestic sewage in an M-shaped constructed wetland.

In order to achieve the above purpose, the M-type constructed wetland device provided by the present invention for advanced treatment of rural domestic sewage mainly includes:

The first-level grid machine is connected to the second-level grid machine;

The secondary grid machine is connected to the M-type constructed wetland;

The water outlet of the M-type constructed wetland is connected to the surface turbulence screening device through a booster pump;

The water outlet of the surface turbulence screening device is connected to the water outlet tank;

in:

The M-type artificial wetland is a concrete wall with anti-seepage treatment. It is divided into two parts by the partition wall. The water inlet side is higher than the water outlet side as a whole;

Each part of the M-shaped constructed wetland is divided into two areas. The two sides close to the partition wall are filled with A mixed filler and B mixed filler respectively, and the two sides close to the concrete wall are filled with pebbles to isolate impurities in the sewage. ;

There is a gap between the bottom of the partition wall and the bottom of the M-shaped artificial wetland, and a drilled PVC pipe is respectively provided on both sides of the gap parallel to the bottom of the M-shaped artificial wetland, and both PVC pipes are filled with zeolite fillers; The space formed between the two PVC pipes, the partition wall and the M-shaped artificial wetland is filled with zeolite filler for passing water;

The effluent of the M-type constructed wetland enters the surface turbulence screening device through the booster pump;

The surface turbulence screening device is divided into upper and lower parts by a porous plate. A sieve packing is laid on the top of the porous plate. A nano aeration head is provided at the bottom of the sieve packing. The surface of the sieve packing is filled with a molecular sieve packing. A shrinkage inlet pipe is installed in the packing; the surface turbulence screening device is located under the other side of the shrinkage inlet pipe, and a shrinkage backwash pipe is set in the screening packing, which is connected to the outlet pool through a booster pump; the surface turbulence screening The device is located above the necking backwash pipe, and a reflux tank is installed. An aeration tube is installed on the side of the reflux tank above the filter packing. The aeration tube is provided with multiple vertically upward aeration holes; There is an ultrasonic generator; below the porous plate is a water storage tank, and the inner wall of the water storage tank is evenly loaded with a layer of non-metallic doped photocatalyst. The bottom of the water storage tank is equipped with an ultraviolet sterilizing lamp, and a nano aeration head is installed in the gap of the ultraviolet sterilizing lamp. The remaining space inside the surface turbulence screening device is filled with semiconductor-loaded fillers.

In the M-type constructed wetland device for advanced treatment of rural domestic sewage, the filtration accuracy of the primary grid and the secondary grid are 21 mm and 8 mm, respectively.

In the M-type constructed wetland device for advanced treatment of rural domestic sewage, the mixed filler on the water inlet side of the M-type constructed wetland is prepared by mixing slow-release molecular sieves prepared from fly ash and activated carbon at a volume ratio of 1:2-5. The mixed filler on the water outlet side is made of flori diatomaceous earth and red mud molecular sieve in a volume ratio of 1:2-5.

In the device for the advanced treatment of rural domestic sewage in the M-type constructed wetland, calamus for shallow water is planted in the area of the M-type constructed wetland near the second-level grid machine, and emergent plants are planted in the area near the surface turbulence screening device. reed.

In the M-type constructed wetland device for advanced treatment of rural domestic sewage, the molecular sieve filler in the surface turbulence screening device is a granular molecular sieve prepared from fly ash.

In the M-type artificial wetland device for advanced treatment of rural domestic sewage, the sieve filler in the surface turbulence sieve device is made of quartz sand, modified manganese sand and natural zeolite molecular sieve.

In the M-type artificial wetland advanced treatment device for rural domestic sewage, the non-metallic doped photocatalyst in the surface turbulence screening device is nano- _TiO2 powder, and the semiconductor-loaded filler is nano- _TiO2 powder loaded on a three-dimensional network polymer. Acrylic filler.

The method for the M-type artificial wetland advanced treatment of rural domestic sewage provided by the present invention, its process is:

The two-stage grille machine can effectively intercept solids of different particle sizes in the sewage with two filtration precisions, and initially realize solid-liquid separation, block large solids in sewage, reduce solid content in sewage, and prevent suspended solids from affecting sewage. impact on subsequent processing;

The M-type constructed wetland is divided into two parts by a partition wall, each part is divided into two areas, each area is an upflow type and a downflow type, and the filler filled in the B area is used to absorb a large amount of pollution load and gradually release it slowly. In order to reduce the pollution load and toxicity, at the same time, the C area uses the alkaline red mud molecular sieve as the filler to quickly absorb and neutralize the small molecule acid produced by the anaerobic partial acidification, adjust the pH of the sewage, and make the internal environment of the device more suitable for the survival of plants and microorganisms; At the same time, create an alkaline environment to fix the heavy metals in the sewage to prevent their leaching, use small molecular organic matter to supply plant nutrients, and absorb and absorb heavy metals in the process of plant growth for heavy metal biostabilization. Biofilms are formed on the surface of all mixed fillers, and aerobic, anoxic, and anaerobic states are formed from top to bottom, and pollutants in sewage are removed under the synergy of plant roots and microorganisms;

The surface turbulence screening device introduces the effluent of the M-type constructed wetland during screening. During the water intake process, the impact force of the cross-flow of the incoming water is used to disturb the surface layer of the sieve packing and molecular sieve packing to form a turbulent flow and prevent pollutants from accumulating on the surface against the water flow. The smooth passage of the water forms resistance; the air bubbles push the floating pollutants to the water surface and overflow to the return tank, where they mix with the incoming water to adjust the incoming water quality;

The air intake of the nano-aeration head of the filter packing in the surface turbulence screening device is O ₂ , which is used to clean the filter packing; the intake air of the nano-aeration head in the water storage tank is O ₃ , and hydroxyl radicals are obtained through nano-aeration , together with the ultraviolet sterilizing lamp and the semiconductor-loaded filler, it improves the advanced oxidation effect, and at the same time, the effluent rich in hydroxyl radicals flushes the sieve packing when the device is backwashed, so that the sieve packing can be cleaned and regenerated;

The nano-aeration method is used in the surface turbulent sieving device to increase ^the OH production rate, so that the microbubbles have a large number, specific surface area, and slow rising speed, and increase the gas-liquid contact area and contact time to facilitate the dissolution of ozone in water. Overcome the shortcomings of ozone insoluble in water; the pressure inside the microbubbles and the interface disappears when the nanobubbles are broken, and the chemical energy generated by the drastic changes in the surrounding environment promotes the generation of more hydroxyl radicals, enhancing the ability of ozone to oxidize and decompose organic matter;

Ozone produces OH under the irradiation of ultraviolet light, and ozone takes away the electrons in the photoinduced electron-hole pairs of titanium dioxide, thereby generating more hydroxyl radicals and accelerating the degradation of organic matter. Organic pollutants are treated.

The effluent from the surface turbulence screening device flows back to the M-type constructed wetland to regulate water quality and stimulate the secretion of secondary substances during plant growth.

In the method for the advanced treatment of rural domestic sewage in the M-type constructed wetland, the average irradiation dose of the ultraviolet sterilizing lamp is above 300J/m ² .

The process of the present invention is simple in operation and obvious in effect. The improved M-type constructed wetland and the surface turbulence screening device are used for advanced treatment of rural domestic sewage by mechanical method and ecological method. The improved treatment technology of artificial wetland prolongs the residence time of sewage in a limited space, improves the efficiency of sewage treatment, and builds a more complex and effective treatment environment. At the same time, it breaks the traditional process concept. Under the irradiation, free negative ions with great oxidative power are excited, and at the same time, the energy excited during the nano-aeration process and the ultrasonic generation process can also occur and strengthen the generation of free negative ions to achieve the photocatalytic effect; while free negative ions and their ability to get rid of covalent bonds After being bound, vacancies are left, and the micro-electrolysis effect is produced at the same time as the charge on the surface of the nanobubbles, which can kill Escherichia coli, Staphylococcus aureus, viruses, etc., decompose residual refractory organic compounds and toxic substances, and carry out long-term and safe treatment of sewage Disinfection degradation. It has great advantages in the treatment of environmental hormones (such as hormone pesticides, antibiotics, dioxins, estrogens, and artificial synthetic hormones and other trace harmful chemicals), which can completely mineralize or decompose most of the organic matter. While the sewage is screened and treated, the effluent is purified and disinfected, and the effluent better meets the national requirements.

Description of drawings

Fig. 1 is a schematic diagram of an M-type constructed wetland device for advanced treatment of rural domestic sewage according to the present invention. Explanation of main component symbols in the attached drawings:

1 first-level grid machine; 2 second-level grid machine; 3 concrete wall; 4 calamus; 5 cobblestone; 6 partition; Valve; 11 Shrink inlet pipe; 12 Molecular sieve filler; 13 Surface turbulence screening device; 14 Screen filler; 15 Shrink backwash pipe; 16 Backwash valve; 17 Outlet pool; 18 Hydraulic pump; Water outlet valve; 21 UV sterilizing lamp; 22 porous plate; 23 nanometer aeration head; 24 semiconductor loaded filler; 25 water storage tank; 26 nanometer aerator; 27 drilled PVC pipe; 28 zeolite filler; Aeration pipe; 31 reflux tanks.

detailed description

Describe in detail below in conjunction with accompanying drawing. It should be noted that the left, right, up, down, etc. mentioned in the following descriptions are all based on the directions shown in the drawings.

See Figure 1. The M-type artificial wetland advanced treatment device for rural domestic sewage provided by the present invention, its main structure includes:

The first-level grid machine 1 is connected to the second-level grid machine 2, and the second-level grid machine 2 is connected to the M-shaped artificial wetland 8, and two filtering precisions (two-level grid machine filtration precision are 21mm and 8mm respectively) are used for sewage Effectively intercept solids of different particle sizes, initially realize solid-liquid separation, block large solids in sewage, reduce solid content in sewage, and prevent suspended solids from affecting the subsequent treatment of sewage.

The water outlet of the M-type constructed wetland 8 is connected to the surface turbulent filtering device 13 through the booster pump 9, and the water outlet of the surface turbulent filtering device 13 is connected to the water outlet pool.

The M-type artificial wetland 8 is a concrete wall, which is treated with anti-seepage. The wetland is divided into two parts by the partition wall 8a. Surface turbulence screening device 13 side), wherein each part is divided into two areas again, A area and B area are an area, C area and D area are an area. Area A is an upflow type filled with pebbles 5 to isolate impurities in the sewage. Area B is a downflow type filled with a mixed filler 7a, which is a slow-release molecular sieve and activated carbon prepared by fly ash in a volume ratio of 1:2 -5 mixed, the surface of the mixed filler 7 forms a biofilm, and forms aerobic, anoxic, and anaerobic states from top to bottom, and removes pollutants in the sewage under the synergistic action of the plant root system 4 and microorganisms (the left half of the planted Calamus for shallow water, and the right half is planted with emergent plants reed). Zone C is an upflow type, filled with mixed filler 7b, which is made of flori diatomaceous earth and red mud molecular sieve at a volume ratio of 1:2-5; zone D is a downflow type, filled with pebbles 5, The large gaps of the pebbles 5 facilitate the export of the effluent, and the exported effluent is sprayed into the surface turbulence screening device 13 under the action of the booster pump 19 .

There is a gap between the bottom of the partition wall 8a and the bottom of the M-shaped constructed wetland 8, and a drilled PVC pipe 27 is respectively arranged on both sides of the gap, and both PVC pipes 27 are filled with zeolite filler. The space formed between the two PVC pipes 27, the partition wall 8a and the M-type constructed wetland 8 is filled with zeolite filler for passing water.

The surface turbulence filtering device 13 is divided into upper and lower parts by a perforated plate 22 . The holes of the perforated plate 22 are inclined (the present embodiment is inclined to the right), and a sieve packing 14 is laid on the top of the perforated plate 22. The sieve packing 14 is a mixture of quartz sand, modified manganese sand and natural zeolite molecular sieve. It is a multi-functional mixed packing integrating filtration, adsorption, ion exchange, coagulation and removal of heavy metals. The bottom of the sieve packing 14 is provided with a nano-aeration head 23, and the surface layer of the sieve packing 14 is filled with a molecular sieve packing 12 prepared from fly ash, and a shrinkage inlet pipe 11 is installed in the molecular sieve packing 12. The narrowed water inlet pipe 11 is connected with the water outlet of the M-type constructed wetland 8 through a booster pump 19 . The surface turbulence screening device 13 is located under the other side of the constricted water inlet pipe 11 , and a constricted backwash pipe 15 is provided in the screening packing 14 , and is connected to the water outlet pool 17 through a booster pump 19 . The surface turbulence screening device 13 is located above the shrinkage backwash pipe 15 and is provided with a backflow tank 31 . An aeration tube 30 is arranged above the sieve packing 14 on one side of the reflux tank 31, and the aeration tube 30 is provided with a plurality of fine-pore aeration holes, and the fine-pore aeration holes are vertically upward; an ultrasonic generator is installed above the sieve packing 14 Instrument 29. Below the porous plate 22 is a water storage tank 25, and the inner wall of the water storage tank 25 is evenly loaded with a layer of non-metallic doped photocatalyst. The bottom of the water storage tank 25 is equipped with an ultraviolet sterilizing lamp 21, and a nano aeration head is installed in the gap between the ultraviolet sterilizing lamp 21 23. The remaining space inside the surface turbulence screening device 13 is filled with semiconductor-loaded fillers 24 (such as nano- _TiO2 powder loaded on three-dimensional network polypropylene fillers). The present invention fixes the semiconductor-loaded fillers 24 on the carrier to solve the problem of conventional light Catalysts need the disadvantages of dispersants to be used together, which reduces the loss of catalysts and avoids the separation step of catalysts after the reaction.

When the surface turbulence screening device 13 performs screening, the nano-aeration in the water storage tank 25 is aerated intermittently. Break up the pollutant layer on the surface of the sieve packing and molecular sieve packing and make it float, so that the sewage can pass through the sieve packing smoothly; there is an aeration tube at the right end above the sieve packing, and the aeration tube is equipped with multiple fine holes The air hole and the aeration hole are vertically upward, and the air bubbles push the floating pollutants to the water surface, overflow to the return tank on the right side, mix with the influent water to adjust the influent water quality, and prolong the service life of the screening device and the backwash cycle. For the case of low influent turbidity, it can even run continuously to purify sewage without backwashing.

The air intake of the nano-aeration head at the bottom of the filter packing is O ₂ for cleaning the packing; the air intake of the nano-aeration head in the water storage tank is O ₃ , and a large amount of hydroxyl radicals are obtained through nano-aeration, which is compatible with ultraviolet sterilization lamps and semiconductors. Loaded fillers work together to improve the advanced oxidation effect, and at the same time, the effluent rich in hydroxyl radicals flushes the sieve fillers when the device is backwashed, so that the fillers are cleaned and regenerated better.

Use nano-aeration to increase ^the OH production rate. Because the microbubbles have a large number, specific surface area, and slow rising speed, the gas-liquid contact area and contact time are greatly increased, which is conducive to the dissolution of ozone in water and overcomes the difficulty of ozone. The disadvantage of being soluble in water. The inside of the microbubbles has a large pressure and the interface disappears when the nanobubbles are broken. The chemical energy generated by the drastic changes in the surrounding environment promotes the generation of more hydroxyl radicals, which enhances the ability of ozone to oxidize and decompose organic matter.

Ozone produces OH under the irradiation of ultraviolet light, and the average irradiation dose of ultraviolet germicidal lamp is above 300J/ ^m2 . Ozone can take away the electrons in the photo-induced electron-hole pairs of titanium dioxide, thereby generating more hydroxyl radicals, accelerating the degradation of organic matter, and treating organic pollutants through the strong oxidation of OH.

When the surface turbulence screening device is working, the outlet water of the M-type constructed wetland is introduced, and the water inlet pipe is buried in the surface layer of the molecular sieve packing. During the water intake process, the impact force of the cross-flow of the incoming water is used to disturb the surface layer of the molecular sieve packing to form a turbulent flow and prevent pollutants from being deposited on the surface. Accumulation forms resistance to the smooth passage of water flow; during backwashing, the nano-aeration head starts to aerate, and in the case of high-temperature nano-aeration, the sand particles are subjected to nano-aeration treatment. Under the action of the impact force generated during the aeration process, the impurities, colloids and biofilms grown on the surface are cleaned. At the same time, the supernatant liquid in the outlet pool is introduced through the backwash pipe for backwashing. The shrinking backwash pipe exerts an inward force on the filter packing, and the air on the liquid surface is strongly squeezed during the filling process of the water storage tank. , rise to the filter packing layer through the porous plate, so that the filter packing presents a state of boiling flow. After the air in the water storage tank is emptied, the water flow continues to flow upward at a high speed through the holes of the porous plate, and at the same time, the shrinkage backwashes during the entire backwashing process. The water in the pipe is flushed inward, and the fillers (filter fillers and molecular sieve fillers) of the entire surface turbulence screening device form a fast-moving turbulent flow under the impact of the water flow. By rubbing against each other, the attached organic pollutants can be removed, which is beneficial to obtain relatively pure fillers. The water outlet of the water storage tank of the surface turbulence screening device is connected with the water outlet pool through a hydraulic pump.

The device of the present invention is simple in operation and obvious in effect. It uses M-type artificial wetland and surface turbulence screening device to treat rural domestic sewage in depth. It has fast processing speed, short processing cycle and easy operation. Wetland improvement treatment technology prolongs the residence time of sewage in a limited space, improves sewage treatment efficiency, and builds a more complex and effective treatment environment. At the same time, it breaks the traditional process concept and kills E. coli, Staphylococcus aureus, viruses, etc., and decomposes residues Refractory organic compounds and toxic substances can disinfect and degrade sewage in a durable and safe manner. It has great advantages in the treatment of environmental hormones (such as hormone pesticides, antibiotics, dioxins, estrogens, and artificial synthetic hormones and other trace harmful chemicals), which can completely mineralize or decompose most of the organic matter. While the sewage is screened and treated, the effluent is purified and disinfected, and the effluent better meets the national requirements.

According to an embodiment of the present invention, the removal rate of heavy metals is as high as 100%, the content of trace organic matter is reduced by more than 95%, and the characteristic fluorescence peak of proteinoid substances is reduced by more than 90%.

The present invention adopts successive three-stage backwashing technology for backwashing:

The first level of backwash is an aeration cycle backwash. Due to the accumulation of pollutants on the surface of the filler, it is difficult for the sewage to penetrate through the gaps between the fillers. Backwash is carried out during the screening process, and the aeration pipe 30 is opened and the porous is intermittently opened. The nano-aerator 26 above the plate, the nano-aerator head in the water storage tank does not work continuously, the air bulges upward from the porous plate, and is divided into small bubbles, which intermittently wash away the dense dirt layer on the sieve packing, and the pollutant layer is broken Floating in flakes, under the synergistic effect of the buoyancy of the air bubbles in the aeration tube and the rightward thrust of the shrinking tube when it enters the water, a pulsator effect is produced, vigorously cleaning the flaky and dense pollutants on the surface of the packing, and overflowing to the return tank, so that the packing The intercepted pollutants are concentrated and removed from the device, mixed with the influent for retreatment, and the sewage can continue to permeate through the molecular sieve gap; the first-stage backwash can prolong the service life of the screening device and the backwash cycle. In some cases, there is even no need for backwashing, so that the device can continue to operate to purify sewage.

The second-stage backwash is an air pulse backwash. Due to the high turbidity of the sewage, a large amount of pollutants accumulate on the surface of the filler. The effect of continuous screening cannot be achieved only by the first-stage backwash step. Now close the water inlet valve 10, the water outlet valve 20, open the backwash valve 16, start the booster pump 19, the aeration pipe 30 and two nano aerators 26, and the water outlet in the outlet pool is imported in the water storage tank. Under the action of the return water pressure, all the air in the water storage tank is quickly squeezed and rises along the pores, and the entire sieve packing layer is affected by the rising air, the action of the wave wheel of the rotating disturbance and the action of the nano-aeration head under the sieve packing. Under the action of the impact force, the pollutants in the filler gap are broken and floated, and under the synergistic effect of the buoyancy of the aeration tube and the rightward thrust of the incoming water impact baffle, they overflow to the return tank and mix with the initial incoming water. decline. After the filtration rate is stabilized again, close the booster pump 19, the nano aerator 26 under the perforated plate, the backwash valve 16, open the water inlet valve 10 and the water outlet valve 2, and continue the screening process.

The third-stage backwashing is aeration turbulent backwashing. At this time, the first and second-stage backwashing are not enough to solve the problem of covering and blocking the filler by pollutants, and a large amount of sewage cannot be filtered. Now close the water inlet valve 10, open the backwash valve 16, the water outlet valve 20, start the booster pump 19, the aeration pipe 30 and two nano aerators 26, the ultrasonic generator 29, start the hydraulic pump 18 in reverse, and A large amount of effluent in the effluent pool is introduced into the sump. (1) The air in the sump rises and stirs along the pores of the porous plate, the nano-aeration head at the bottom of the filler starts to aerate, and the turbine above the filler rotates continuously; (2) Using nano-aeration technology for shock, oxidation, air flotation and high-temperature cleaning , the upper packing presents a state of turbulent flow and is in a state of irregular high-speed motion. The packing rubs against each other under the impact force of the vortex of the water flow and the shear force of the air bubbles, and the organic pollutants attached to the packing can be removed to obtain a relatively pure packing; (3 )Using an ultrasonic generator to generate ultrasonic waves in the liquid medium, the cavitation effect is generated on the surface of the filter packing, and the shock wave formed when the cavitation bubble breaks during the closing process will generate thousands of air pressure shock pressure around it. Break the stickiness between the dirt on the surface of the filler, and make them quickly disperse in the backwash solution, so as to achieve the effect of cleaning the surface of the filler. (4) After the air is exhausted, the effluent from the effluent tank continues to be introduced. Nano-aeration and ultrasonic waves can promote the generation of hydroxyl radicals. The effluent rich in hydroxyl radicals washes the surface and micropores of filler particles in a turbulent state, and strips pollutants. , the filler is regenerated. (5) The pollutants continuously float up to the water surface under the impact of the water flow and the air flotation of the right aeration tube, and flow out from the water inlet weir at the left end and the reflux tank at the right end to mix with the initial water inlet. After three-stage backwashing, the internal pollutants are cleaned and emptied.

Conventional sand filtration does not disturb the sand layer during the filtration process, allowing water to flow through the small gaps in the sand. Usually, the sand filtration process is improved by means of not disturbing the sand layer, compacting the filler, increasing the water pressure, and adding grids on the sand, so that the water flows through the small gaps in the sand, while the pollutants stay on the surface of the sand layer. The present invention utilizes the high-pressure water inlet of the constricted tube to disturb the surface layer of the filler, prevents the accumulation of pollutants from forming resistance to the smooth passage of the water flow, and uses advanced oxidation, ultrasonic waves, nano-aeration, impact force and shear force of air bubbles to improve the device. , use molecular sieve, manganese sand and other fillers to optimize the design, and finally use three-stage backwashing to improve the treatment process. The device has a good interception effect on suspended solids such as colloids, fibers, algae, etc. For water with low turbidity, the treatment process can be completed even without backwashing. At the same time, it can remove odors, kill bacteria, pathogenic bacteria, etc. The efficacy of a small amount of residual surfactants, polychlorinated biphenyls and other refractory organic compounds.

Nano _TiO of the present invention's semiconductor loaded filler-carbon doping Preparation of powder:

Carbon-doped nano-TiO ₂ was prepared by a two-step process of uniform precipitation and hydrothermal method. With titanium sulfate and urea as the precursor, glucose as the carbon source, the specific preparation process is as follows: dissolve titanium sulfate and urea in deionized water, then add an appropriate amount of glucose and stir evenly, the molar ratio of titanium sulfate: urea: glucose = 1:2 : 0.023, reacted at 90°C for 2h. After the reaction is finished, the reactant is taken out and dried, repeatedly washed with water until neutral, dried again, and ground with a ball mill to obtain carbon-doped nano TiO ₂ powder.

The method of loading nano TiO ₂ powder on the filler:

The three-dimensional network structure filler made of polypropylene is used to mix nano-TiO ₂ powder with deionized water (the mass ratio of powder to water is 1:20), and the emulsion is formed by ultrasonic wave, and the clean three-dimensional network The structural filler is immersed in a titanate coupling agent mixed with ethanol at a volume ratio of 1:1, stirred slowly for a period of time, then the filler is taken out and placed in the TiO ₂ emulsion to continue stirring for a period of time, and then placed in an oven to dry (85 ℃) 2h, that is, the polypropylene suspension filler loaded with nano TiO ₂ is prepared, its appearance is light yellow, and the film layer is relatively uniform.

Claims (10)

1. An M-type constructed wetland device for advanced treatment of rural domestic sewage, mainly including: The first-level grid machine is connected to the second-level grid machine; The secondary grid machine is connected to the M-type constructed wetland; The water outlet of the M-type constructed wetland is connected to the surface turbulence screening device through a booster pump; The water outlet of the surface turbulence screening device is connected to the water outlet tank; in: The M-type artificial wetland is a concrete wall with anti-seepage treatment. It is divided into two parts by the partition wall. The water inlet side is higher than the water outlet side as a whole; The M-shaped artificial wetland is divided into two areas by the partition wall, the two sides near the partition wall are filled with mixed filler, and the two sides near the concrete wall are filled with pebbles to isolate impurities in the sewage; There is a gap between the bottom of the partition wall and the bottom of the M-shaped artificial wetland, and a drilled PVC pipe is respectively provided on both sides of the gap parallel to the bottom of the M-shaped artificial wetland, and both PVC pipes are filled with zeolite fillers; The space formed between the two PVC pipes, the partition wall and the M-shaped artificial wetland is filled with zeolite filler for passing water; The effluent of the M-type constructed wetland enters the surface turbulence screening device through the booster pump; The surface turbulence screening device is divided into upper and lower parts by a porous plate. A sieve packing is laid on the top of the porous plate. A nano aeration head is provided at the bottom of the sieve packing. The surface of the sieve packing is filled with a molecular sieve packing. A shrinkage inlet pipe is installed in the packing; the surface turbulence screening device is located under the other side of the shrinkage inlet pipe, and a shrinkage backwash pipe is set in the screening packing, which is connected to the outlet pool through a booster pump; the surface turbulence screening The device is located above the necking backwash pipe, and a reflux tank is installed. An aeration tube is installed on the side of the reflux tank above the filter packing. The aeration tube is provided with multiple vertically upward aeration holes; There is an ultrasonic generator; below the porous plate is a water storage tank, and the inner wall of the water storage tank is evenly loaded with a layer of non-metallic doped photocatalyst. The bottom of the water storage tank is equipped with an ultraviolet sterilizing lamp, and a nano aeration head is installed in the gap of the ultraviolet sterilizing lamp. The remaining space inside the surface turbulence screening device is filled with semiconductor-loaded fillers. 2. The device for advanced treatment of rural domestic sewage in an M-shaped constructed wetland according to claim 1, wherein the filtration accuracy of the primary grid and the secondary grid are 21mm and 8mm respectively. 3. according to the device of the described M type constructed wetland advanced treatment of rural domestic sewage of claim 1, wherein, the mixed filler of the water inlet side in the M type constructed wetland is the slow-release molecular sieve prepared by fly ash and activated carbon by volume ratio It is formed by mixing 1:2-5, and the mixed filler on the water outlet side is formed by mixing flori diatomaceous earth and red mud molecular sieve in a volume ratio of 1:2-5. 4. according to claim 1 described M-type constructed wetland advanced treatment device for rural domestic sewage, wherein, the area of the M-type constructed wetland near the secondary grid machine side is planted with calamus for shallow water, close to the surface turbulence screening device Emergent plants reeds are planted in the side area. 5. The device for advanced treatment of rural domestic sewage in an M-type constructed wetland according to claim 1, wherein the molecular sieve filler in the surface turbulence screening device is a granular mesoporous molecular sieve prepared from fly ash. 6. according to claim 1 described M-type artificial wetland advanced treatment device of rural domestic sewage, wherein, the sieve filter filler in the surface layer turbulence sieving device is to be mixed by quartz sand, modified manganese sand and molecular sieve, wherein doped A small amount of zero-valent nano-iron. 7. according to claim 1 said M-type artificial wetland advanced treatment device of rural domestic sewage, wherein, the non-metallic doped photocatalyst in the surface layer turbulent sieving device is nano TiO ₂ powder, and the semiconductor loaded filler is nano TiO ₂ powder Body loaded in three-dimensional reticulated polypropylene packing. 8. A method for advanced treatment of rural domestic sewage in an M-shaped constructed wetland, the process of which is: The two-stage grille machine can effectively intercept solids of different particle sizes in the sewage with two filtration precisions, and initially realize solid-liquid separation, block large solids in sewage, reduce solid content in sewage, and prevent suspended solids from affecting sewage. impact on subsequent processing; The M-type constructed wetland is divided into two parts by a partition wall, each part is divided into two areas, each area is an upflow type and a downflow type, and the mixed filler surface filled inside forms a biofilm, forming an aerobic, Under anoxic and anaerobic conditions, pollutants in sewage are removed under the synergistic effect of deep plant roots and microorganisms; The surface turbulence screening device introduces the effluent of the M-type constructed wetland during screening. During the water intake process, the impact force of the cross-flow of the incoming water is used to disturb the surface layer of the sieve packing and molecular sieve packing to form a turbulent flow and prevent pollutants from accumulating on the surface against the water flow. The smooth passage of the water forms resistance; the air bubbles push the floating pollutants to the water surface and overflow to the return tank, where they mix with the incoming water to adjust the incoming water quality; In the surface turbulence screening device, the air intake of the nano-aeration head of the filter packing is O ₂ , which is used to clean the filter packing; the air intake of the nano-aeration head in the water storage tank is O ₃ , and OH is obtained through nano-aeration, Together with the ultraviolet sterilizing lamp and the semiconductor loaded filler, the advanced oxidation effect is improved. At the same time, the OH-rich effluent flushes the sieve packing when the device is backwashed, so that the sieve packing can be cleaned and regenerated; The nano-aeration method is used in the surface turbulence screening device to increase the OH generation rate, so that the microbubbles have a large number, specific surface area, and slow rising speed, and increase the gas-liquid contact area and contact time to facilitate the dissolution of ozone in water. Overcome the disadvantage that ozone is insoluble in water; the microbubbles have pressure inside and the interface disappears when the microbubbles break, and the chemical energy generated by the drastic changes in the surrounding environment promotes the production of more OH, which enhances the ability of ozone to oxidize and decompose organic matter; Ozone produces OH under the irradiation of ultraviolet light, and ozone takes away the electrons in the photo-induced electron-hole pairs of titanium dioxide, thereby generating more OH, which accelerates the degradation of organic matter, and through the strong oxidation of OH to the organic Pollutants are treated. 9. The method for the advanced treatment of rural domestic sewage in the M-type constructed wetland according to claim 8, wherein the average irradiation dose of the ultraviolet sterilizing lamp is above 300 J/m ² . 10. The method for advanced treatment of rural domestic sewage in the M-type constructed wetland according to claim 8, wherein the effluent from the surface turbulence screening device flows back into the M-type constructed wetland to adjust the water quality and stimulate the secretion of secondary substances during plant growth.