Ecological filter bed reinforcing material, preparation method and sewage advanced treatment constructed wetland system

Abstract

The invention discloses an ecological filter bed reinforcing material, a preparation method and a sewage advanced treatment artificial wetland system, the material comprises the following raw materials: an electron donor, an electron conductor, a phosphorus removal reinforcing agent, a binding agent and a foaming agent, the material is spherical particles, the particle size of the spherical particles is 0.5-1.0 cm, the BET specific surface area is 120-200m < 2 > / g, the porosity is 55-70%, the bulk density is 0.8-1.3 g / cm < 3 >, and the particle size of the spherical particles is 0.5-1.0 cm. The bearing strength is 1.5 to 2.0 MPa; the method comprises the following steps: under the bonding action of a binding agent and the foaming action of a foaming agent, sequentially mixing and stirring an electron donor, an electron conductor and a dephosphorization enhancer, granulating, drying, calcining at high temperature, and naturally cooling to obtain the ecological filter bed reinforcing material, by coupling an ecological filter bed reinforcing material with a sewage advanced treatment artificial wetland system, the removal rate of NH4 < + >-N, COD, TN and TP in sewage is greatly improved, the technical problem of nitrogen removal by denitrification caused by insufficient carbon sources in tail water of a sewage plant is solved, and the system has the characteristics of good effluent quality, low energy consumption and medicament saving.

Description

Technical Field

[0001] The present invention relates to the technical field of domestic sewage treatment, and in particular to an ecological filter bed reinforcing material, a preparation method and an artificial wetland system for sewage deep treatment. Background Art

[0002] In the process of deep sewage treatment, artificial wetland, an ecological technology, is widely used due to its advantages such as energy saving, simple operation and low operation and maintenance cost. However, traditional artificial wetland technology has technical problems such as limited denitrification and phosphorus removal load, inability to deeply remove nitrogen due to the low carbon-nitrogen ratio (C / N ratio) of sewage in sewage treatment plants, and low phosphorus adsorption efficiency of fillers.

[0003] Yang Xiao et al. (Yang Xiao, Bi Haiquan, Pan Guofeng. Experimental study on blackwater treatment based on A / O-MBR process [J]. Refrigeration and Air Conditioning (Sichuan), 2022, 36(06): 924-928.) combined the A / O process with the MBR process (membrane bioreactor) to form an A / O-MBR process (anaerobic aerobic-membrane bioreactor combined process) to efficiently treat blackwater, but the process was not effective in removing TP.

[0004] Li Yaocheng (Li Yaocheng. Analysis of the operating effect of the combined process of MBR and artificial wetland in industrial wastewater treatment plants [J]. Chemical Engineering Management, 2022, (30): 49-52.) proposed the use of a combined process of hydrolysis acidification + A2O-MBR + vertical flow artificial wetland, which greatly improved the COD removal effect and achieved the goals of nitrogen removal and phosphorus removal. However, due to the low influent concentration in the rainy season, the carbon-nitrogen ratio did not meet the denitrification reaction conditions, resulting in limited removal capacity for total nitrogen.

[0005] The Chinese invention patent application with publication number CN113716810A discloses an integrated A2O process for nitrogen removal and phosphorus removal using core-shell tourmaline particles; the core-shell tourmaline particles effectively promote the treatment of denitrifying bacteria, greatly improve the nitrate treatment efficiency, and also increase the nitrate treatment volume without the need for subsequent reflux treatment. However, an external carbon source is required during the treatment process to achieve the denitrification reaction, resulting in high treatment costs. Summary of the invention

[0006] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide an ecological filter bed reinforcement material, a preparation method and an artificial wetland system for deep treatment of sewage. By adding a foaming agent, sodium bicarbonate, in the synthesis of the ecological filter bed reinforcement material, the porosity of the material can be increased, and adding an adhesive, food-grade carboxymethyl cellulose, can increase the compressive strength of the material, thereby solving the technical problems of low porosity and weak compressive strength of traditional iron-carbon materials; by increasing the mass fraction of powdered activated carbon in the ecological filter bed reinforcement material, the specific gravity of the material is reduced; in a low temperature environment, by introducing the ecological filter bed reinforcement material in the artificial wetland treatment process, electron transfer can be enhanced, thereby solving the technical problem of denitrification and denitrification caused by insufficient carbon source in the tail water of the sewage treatment plant; phosphorus removal is further enhanced by PAC, thereby solving the technical problem of low phosphorus removal efficiency of the ecological filter bed; the artificial wetland system for deep treatment of sewage of the present invention does not require the addition of a carbon source, and has the characteristics of good effluent water quality, low energy consumption and saving of reagents.

[0007] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is as follows:

[0008] An ecological filter bed strengthening material, the raw materials of which include an electron donor, an electron conductor, a phosphorus removal strengthening agent, a binder and a foaming agent, the material is a spherical particle, the particle size of the spherical particle is 0.5-1.0 cm, and the BET specific surface area is 120-200 m 2 / g, porosity 55%-70%, bulk density 0.8-1.3g / cm 3 , the bearing strength is 1.5-2.0MPa.

[0009] The electron donor is a mixture of reduced iron powder and scrap iron, the electron conductor is a mixture of powdered activated carbon and cobalt powder, the phosphorus removal enhancer is polyaluminium chloride (PAC), the binder is food grade carboxymethyl cellulose, and the foaming agent is sodium bicarbonate.

[0010] The mass ratio of the reduced iron powder to the scrap iron is (1-1.5):1, and the mass ratio of the powdered activated carbon to the cobalt powder is (800-1000):1.

[0011] A method for preparing an ecological filter bed strengthening material, comprising:

[0012] The binder, foaming agent, electron donor, electron conductor and phosphorus removal enhancer are sequentially mixed, stirred, granulated, dried, and calcined at high temperature, and then naturally cooled to obtain an ecological filter bed reinforcement material; in terms of mass percentage, electron donor: electron conductor: phosphorus removal enhancer: binder: foaming agent = 70-80%: 10-20%: 3-7%: 2-4%: 1-3%.

[0013] The stirring speed is 90-120r / min, and the time is 20-30min; the drying temperature is 100-105°C, and the time is 3-4h; the high-temperature calcination temperature is 1000-1100°C, and the time is 2-3h; the drying, high-temperature calcination and natural cooling operations are all carried out under anaerobic conditions.

[0014] A sewage deep treatment artificial wetland system comprises the ecological filter bed reinforcement material as described above, or the ecological filter bed reinforcement material prepared by the above preparation method, and the ecological filter bed reinforcement material is evenly distributed in the electron transfer layer 6 of the vertical flow artificial wetland pool.

[0015] The vertical flow artificial wetland pool also includes a cultivation layer 3, an isolation layer 4, a zeolite layer 5, a ceramsite layer 7, and a gravel layer 8 which are laid in sequence according to the direction of water flow, and the electron transfer layer 6 is located between the zeolite layer 5 and the ceramsite layer 7; the thickness ratio of the cultivation layer 3, the isolation layer 4, the zeolite layer 5, the electron transfer layer 6, the ceramsite layer 7 and the gravel layer 8 is 4:1:4:(2-6):(2-6):2.

[0016] The cultivation layer 3 is composed of soil and quartz sand with a volume ratio of 1:1, which is used to support vegetation growth, and the particle size of the quartz sand is 0.1-1mm; the isolation layer 4 is quartz sand with a particle size of 1-3mm, which is used to prevent the soil of the cultivation layer 3 from penetrating downward into each layer; the zeolite layer 5 is biological zeolite with a particle size of 3-5mm, which is used to adsorb and oxidize organic matter and ammonia nitrogen; the ceramsite layer 7 is biological ceramsite with a particle size of 8-15mm, which is used to further remove organic matter, nitrogen and phosphorus; the gravel layer 8 is pebbles with a particle size of 15-30mm, which serves as a drainage layer of the ecological filter bed; reeds and calamus are planted on the cultivation layer according to a planting ratio of 1:1, and the planting density is 20-25 plants / m 2 , forming a vegetation layer.

[0017] The system also includes an inlet pool 1, the outlet pipe of the inlet pool 1 is connected to the inlet pipe of the vertical flow artificial wetland pool through a peristaltic pump 2, and the outlet pipe of the vertical flow artificial wetland pool is connected to the overflow pipe 9 through a three-way air connector 10.

[0018] The optimal operating conditions of the system in sewage treatment are: hydraulic load of 0.6-1.0m 3 /

[0019] (m 2 ·d).

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The present invention adds ecological filter bed strengthening materials to the artificial wetland system. Inorganic electron donors such as iron not only improve the autotrophic denitrification (AD) process and strengthen the denitrification effect, but also the reaction product Fe 3+It can react with phosphate to improve the phosphorus removal effect; at the same time, PAC has the effect of further improving the phosphorus removal efficiency, and enhances the removal of nitrogen and phosphorus in low-nitrogen, high-phosphorus and low-carbon sewage by traditional artificial wetland sewage treatment process. Ecological filter bed reinforcement material coupling sewage deep treatment artificial wetland system in high nitrogen / phosphorus and low-carbon sewage treatment NH4 + The removal rates of -N, COD, TN and TP were 85.3%, 86.17%, 82.6% and 94.8% respectively, and the removal rates of NH4 + -N、NO3 - -N, NO2 - -N and TP effluent concentrations were reduced to 5.40mg / L, 0.61mg / L, 0.30mg / L, 0.22mg / L, respectively. COD, TN and TP removal rates were higher than 81.6%, 51.0%, 38.2% when activated carbon was added. NO3 - -N, NO2 - -N and TP effluent concentrations are lower than 12.40mg / L, 0.93mg / L, and 2.50mg / L when activated carbon is added. The artificial wetland system for deep sewage treatment proposed by the present invention effectively enhances the TN and TP removal efficiency of the A2O process in the treatment of high nitrogen and phosphorus and low C / N ratio sewage.

[0022] 2. The present invention greatly increases the specific surface area, porosity and compressive strength of the material by adding food-grade carboxymethyl cellulose and sodium bicarbonate during the material synthesis process, and enhances the phosphorus removal effect of the material by adding PAC, thereby solving the technical problem of low phosphorus removal efficiency of zero-valent iron itself, and has the characteristics of high efficiency and no pollution.

[0023] 3. The present invention proposes an artificial wetland system for deep sewage treatment coupled with an ecological filter bed reinforcement material, which can overcome the disadvantage that traditional artificial wetland systems for deep sewage treatment require external organic agents, avoid the use of external carbon sources in the system, and reduce operating costs.

[0024] 4. The present invention proposes an artificial wetland system for deep sewage treatment coupled with an ecological filter bed reinforcement material, which can operate normally under cold weather conditions, has a good effect on gray water treatment, solves the problem that traditional artificial wetland systems cannot operate normally under extreme conditions, and has the characteristics of strong adaptability.

[0025] In summary, the ecological filter bed enhancement material is coupled with the sewage deep treatment artificial wetland system. In a low temperature environment of -11.5 to 8.0℃, the in-situ H2 / Fe 2+ Under the supply, the zeolite layer effectively carried out nitrification, phosphorus accumulation and organic matter degradation, and the electron transfer layer carried out efficient H 2- / Fe 2+Autotrophic denitrification and phosphorus fixation greatly increase the NH4 + -N, COD, TN and TP removal rates. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the structure of the artificial wetland system for deep sewage treatment provided by the present invention.

[0027] Figure 2 A structural schematic diagram of an artificial wetland system provided for Comparative Example 1.

[0028] In the figure: water inlet pool 1, peristaltic pump 2, cultivation layer 3, isolation layer 4, zeolite layer 5, electron transfer layer 6, ceramsite layer 7, gravel layer 8, overflow pipe 9, three-way air connector 10, activated carbon layer 11. DETAILED DESCRIPTION

[0029] The technical solution of the present invention is further introduced below in conjunction with the accompanying drawings and specific embodiments.

[0030] An ecological filter bed strengthening material, the raw materials of which include an electron donor, an electron conductor, a phosphorus removal strengthening agent, a binder and a foaming agent; in terms of mass percentage, the electron donor: the electron conductor: the phosphorus removal strengthening agent: the binder: the foaming agent = 70%-80%: 10%-20%: 3%-7%: 2%-4%: 1%-3%; the electron donor is a mixture of reduced iron powder and scrap iron, the mass ratio of the reduced iron powder to the scrap iron is (1-1.5): 1; the electron conductor is a mixture of powdered activated carbon and cobalt powder, the mass ratio of the powdered activated carbon to the cobalt powder is (800-1000): 1; the phosphorus removal strengthening agent is polyaluminium chloride (PAC); the binder is food-grade carboxymethyl cellulose; the foaming agent is sodium bicarbonate; the material is spherical particles, the particle size of the spherical particles is 0.5-1.0cm, and the BET specific surface area is 120-200m 2 / g, porosity 55%-70%, bulk density 0.8-1.3g / cm 3 , the bearing strength is 1.5-2.0MPa.

[0031] A method for preparing an ecological filter bed strengthening material comprises the following steps:

[0032] Under the bonding effect of the binder and the foaming effect of the foaming agent, the binder, foaming agent, electron donor, electron conductor and phosphorus removal enhancer are mixed and stirred at 90-120r / min for 20-30min; then granulation, drying and high-temperature calcination are carried out in sequence, followed by natural cooling to obtain an ecological filter bed reinforcement material with a particle size of 0.5-1.0cm; the drying temperature is 100-105°C and the time is 3-4h; the high-temperature calcination temperature is 1000-1100°C and the time is 2-3h; in order to prevent oxidation of iron filings during the preparation process, drying, high-temperature calcination and natural cooling operations are all carried out under anaerobic conditions; by mass percentage, electron donor: electron conductor: phosphorus removal enhancer: binder: foaming agent = 70%-80%: 10%-20%: 3%-7%: 2%-4%: 1%-3%.

[0033] like Figure 1 As shown, a sewage deep treatment artificial wetland system includes an inlet pool 1, the outlet pipe of the inlet pool 1 is connected with the inlet pipe of the vertical flow artificial wetland pool through a peristaltic pump 2, and is used to collect sewage and drain the sewage into the vertical flow artificial wetland pool; the outlet pipe of the vertical flow artificial wetland pool is connected with the overflow pipe 9 through a three-way air connector 10; the three-way air connector 10 is connected with the vertical flow artificial wetland pool through a pipeline to form a liquid level difference, so that the sewage stays in the vertical flow artificial wetland pool for a long time.

[0034] The vertical flow artificial wetland pool is sequentially paved with a cultivation layer 3, an isolation layer 4, a zeolite layer 5, an electron transfer layer 6, a ceramsite layer 7, and a gravel layer 8 in the direction of water flow; the thickness ratio of the cultivation layer 3, the isolation layer 4, the zeolite layer 5, the electron transfer layer 6, the ceramsite layer 7, and the gravel layer 8 is 4:1:4:(2-6):(2-6):2; the cultivation layer 3 is composed of soil and quartz sand in a volume ratio of 1:1, and is used to support vegetation growth, and the particle size of the quartz sand is 0.1-1mm; the isolation layer 4 is quartz sand with a particle size of 1-3mm, and is used to prevent the soil of the cultivation layer 3 from penetrating downward into each layer; the zeolite layer 5 is quartz sand with a particle size of 3-5 The biological zeolite of mm is used for adsorbing and oxidizing organic matter and ammonia nitrogen; the electron transfer layer 6 adopts the above-mentioned ecological filter bed reinforcement material or the ecological filter bed reinforcement material prepared by the above-mentioned preparation method, which is used to attach denitrifying microorganisms, provide electron donors for autotrophic denitrification, and provide positive complex ions in situ for the removal of total phosphorus; the ceramsite layer 7 is biological ceramsite with a particle size of 8-15mm, which is used for further removal of organic matter, nitrogen and phosphorus; the gravel layer 8 is pebbles with a particle size of 15-30mm, which serves as the drainage layer of the ecological filter bed; reeds and calamus are planted on the cultivation layer according to a planting ratio of 1:1, and the planting density is 20-25 plants / m 2 , forming a vegetation layer.

[0035] The optimal operating conditions of the sewage deep treatment artificial wetland system are: hydraulic load is 0.6-1.0m3 / (m 2 ·d).

[0036] The working principle of the artificial wetland system for deep sewage treatment of the present invention is as follows:

[0037] The above ecological filter bed reinforcement materials were introduced into the vertical flow artificial wetland pool, and effective nitrification, phosphorus accumulation and organic degradation were carried out in the zeolite layer 5, and H2 / Fe2O3 was supplied in situ by Fe / C micro-electrolysis in the electron transfer layer 6. 2+ , achieving H2 / Fe 2+ Mediated efficient autotrophic denitrification and phosphorus fixation.

[0038] Fe(0) and activated carbon (AC) in ecological filter bed reinforcement materials form a galvanic cell including a cathode (Formula (1)) and an anode (Formula (2)) in water. Compared with natural Fe(0) corrosion, using Fe(0) as the only electron donor, the iron-carbon galvanic cell material can induce an effective redox reaction (Formula (3)). Therefore, the iron-carbon galvanic cell material has been used to accelerate the [H] / H2 and Fe 2 + to start the production of H2 / Fe 2+ Supported autotrophic denitrification process (ADP); ecological filter bed enhancement materials were introduced into constructed wetlands to achieve rapid nitrate reduction in groundwater treatment. In addition, Fe 2 + Fe produced by oxidation 3 + Capable of fixing phosphorus, the ecological filter bed reinforcement material is combined with the sewage deep treatment artificial wetland system, so that the system has a high efficiency of nitrogen and phosphorus removal. The following is the relevant formula:

[0039] 2H + +2e - →H2,φ 0 (H / [H])=0.00V (1)

[0040]

[0041] Fe+2H2O→H2 / 2[H]+Fe 2+ +2OH-(3)

[0042] Example 1

[0043] An ecological filter bed strengthening material, the raw materials of which include electron donor, electron conductor, PAC, food-grade carboxymethyl cellulose and sodium bicarbonate; in terms of mass percentage, electron donor: electron conductor: PAC: food-grade carboxymethyl cellulose: sodium bicarbonate = 70%: 20%: 7%: 2%: 1%; the electron donor is a mixture of reduced iron powder and scrap iron, the mass ratio of reduced iron powder to scrap iron is 1:1, the electron conductor is a mixture of powdered activated carbon and cobalt powder, the mass ratio of powdered activated carbon to cobalt is 800:1; the material is spherical particles, the particle size of the spherical particles is 0.5-1.0 cm, and the BET specific surface area is 125-133 m 2 / g, porosity 55%-62%, bulk density 0.9-1.1g / cm 3 , the bearing strength is 1.6-1.8MPa.

[0044] A method for preparing an ecological filter bed strengthening material comprises the following steps:

[0045] Under the action of a binder and a foaming agent, a mixture of reduced iron powder and scrap iron chips, a mixture of powdered activated carbon and cobalt powder, and PAC are stirred at 90 r / min for 30 min; then granulation, drying, and high-temperature calcination are carried out in sequence, followed by natural cooling to obtain an ecological filter bed reinforcement material; the drying temperature is 105°C and the time is 3 h; the high-temperature calcination temperature is 1100°C and the time is 2 h; in order to prevent oxidation of iron chips during the preparation process, drying, high-temperature calcination, and natural cooling operations are all carried out under anaerobic conditions.

[0046] A sewage deep treatment artificial wetland system, in which in a vertical flow artificial wetland pool, the depth of the cultivation layer is 40 cm, the depth of the isolation layer is 10 cm, the depth of the zeolite layer is 40 cm, the depth of the electron transfer layer is 20 cm, the depth of the ceramsite layer is 60 cm, and the depth of the water outlet layer is 20 cm; reeds and calamus are planted at a planting ratio of 1:1, and the planting density is 20-25 plants / m 2 .

[0047] The sewage deep treatment artificial wetland system is used to treat the secondary effluent of the low C / N ratio and high phosphorus sewage plant. The raw water quality is: COD concentration is 88.7-204.1mg / L, NH4 + The concentration of -N is 29.7-41.2mg / L, NO 3- -N and NO 2- -N concentration is less than 0.1mg / L, TP concentration is 2.8-4.9mg / L, hydraulic load is 0.6m 3 / (m 2·d) After 30 days of stable operation, the inlet and outlet water quality was tested and the effluent water quality parameters met the Class A emission limits in the Integrated Wastewater Discharge Standard (GB 18918-2002).

[0048] Example 2

[0049] An ecological filter bed strengthening material, the raw materials of which include electron donor, electron conductor, PAC, food-grade carboxymethyl cellulose and sodium bicarbonate; in terms of mass percentage, electron donor: electron conductor: PAC: food-grade carboxymethyl cellulose: sodium bicarbonate = 80%: 10%: 3%: 4%: 3%; the electron donor is a mixture of reduced iron powder and scrap iron, the mass ratio of reduced iron powder to scrap iron is 1.5:1, the electron conductor is a mixture of powdered activated carbon and cobalt powder, the mass ratio of powdered activated carbon to cobalt is 1000:1; the material is spherical particles, the particle size of the spherical particles is 0.5-1.0 cm, and the BET specific surface area is 175-190 m 2 / g, porosity 66%-69%, bulk density 1.1-1.2g / cm 3 , the bearing strength is 1.8-2MPa.

[0050] A method for preparing an ecological filter bed strengthening material comprises the following steps:

[0051] Under the action of a binder and a foaming agent, a mixture of reduced iron powder and waste iron filings, a mixture of powdered activated carbon and cobalt powder, and PAC are stirred at 120 r / min for 20 min; then granulation, drying, and high-temperature calcination are carried out in sequence, followed by natural cooling to obtain an ecological filter bed reinforcement material; the drying temperature is 100°C and the time is 4 h; the high-temperature calcination temperature is 1000°C and the time is 3 h; in order to prevent oxidation of iron filings during the preparation process, drying, high-temperature calcination, and natural cooling operations are all carried out under anaerobic conditions.

[0052] The sewage deep treatment artificial wetland system and the sewage treated in this embodiment are the same as those in Example 1, and the effluent water quality parameters meet the Class A emission limits in the "Comprehensive Sewage Discharge Standard" (GB 18918-2002).

[0053] Example 3

[0054] An ecological filter bed strengthening material, the raw materials of which include electron donor, electron conductor, PAC, food-grade carboxymethyl cellulose and sodium bicarbonate; in terms of mass percentage, electron donor: electron conductor: PAC: food-grade carboxymethyl cellulose: sodium bicarbonate = 80%: 10%: 5%: 3%: 2%; the electron donor is a mixture of reduced iron powder and scrap iron, the mass ratio of reduced iron powder to scrap iron is 1.5:1, the electron conductor is a mixture of powdered activated carbon and cobalt powder, the mass ratio of powdered activated carbon to cobalt is 1000:1; the material is spherical particles, the particle size of the spherical particles is 0.5-1.0 cm, and the BET specific surface area is 162-182 m 2 / g, porosity 63%-68%, bulk density 1.0-1.2g / cm 3 , the bearing strength is 1.7-1.8MPa.

[0055] A method for preparing an ecological filter bed strengthening material comprises the following steps:

[0056] Under the action of a binder and a foaming agent, a mixture of reduced iron powder and scrap iron chips, a mixture of powdered activated carbon and cobalt powder, and PAC are stirred at 120 r / min for 20 min; then granulation, drying, and high-temperature calcination are carried out in sequence, followed by natural cooling to obtain an ecological filter bed reinforcement material; the drying temperature is 105°C and the time is 3 h; the high-temperature calcination temperature is 1100°C and the time is 2 h; in order to prevent oxidation of iron chips during the preparation process, drying, high-temperature calcination, and natural cooling operations are all carried out under anaerobic conditions.

[0057] A sewage deep treatment artificial wetland system, in which in a vertical flow artificial wetland pool, the depth of the cultivation layer is 40 cm, the depth of the isolation layer is 10 cm, the depth of the zeolite layer is 40 cm, the depth of the electron transfer layer is 40 cm, the depth of the ceramsite layer is 40 cm, and the depth of the water outlet layer is 20 cm; reeds and calamus are planted at a planting ratio of 1:1, and the planting density is 20-25 plants / m 2 .

[0058] The sewage deep treatment artificial wetland system and the sewage quality treated in this embodiment are the same as those in Example 1, except that the hydraulic load is 1.0m 3 / (m 2 ·d) The effluent water quality parameters meet the Class A emission limits in the Integrated Wastewater Discharge Standard (GB18918-2002).

[0059] Example 4

[0060] The ecological filter bed reinforcement materials, preparation methods and treated sewage quality selected in this embodiment and embodiment 3 are the same, except that: when sewage is treated by using the sewage deep treatment artificial wetland system, in the vertical flow artificial wetland pool, the depth of the cultivation layer is 40 cm, the depth of the isolation layer is 10 cm, the depth of the zeolite layer is 40 cm, the depth of the electron transfer layer is 60 cm, the depth of the ceramsite layer is 20 cm, and the depth of the water outlet layer is 20 cm; reeds and calamus are planted at a planting ratio of 1:1, and the planting density is 20-25 plants / m 2 The effluent water quality parameters meet both the Class A emission limits in the Integrated Sewage Discharge Standard (GB 18918-2002) and the Class A emission limits in the Integrated Water Pollutant Discharge Standard (Beijing Local Standard) (DB 11 / 307-2013).

[0061] Example 5

[0062] The ecological filter bed reinforcement materials, preparation methods and treated sewage quality selected in this embodiment and embodiment 3 are the same, except that: when sewage is treated by using the sewage deep treatment artificial wetland system, in the vertical flow artificial wetland pool, the depth of the cultivation layer is 40 cm, the depth of the isolation layer is 10 cm, the depth of the zeolite layer is 40 cm, the depth of the electron transfer layer is 60 cm, the depth of the ceramsite layer is 40 cm, and the depth of the water outlet layer is 20 cm; reeds and calamus are planted at a planting ratio of 1:1, and the planting density is 20-25 plants / m 2 ; Hydraulic load is 0.6m 3 / (m 2 d) The effluent water quality parameters meet the Class A emission limits in the Integrated Wastewater Discharge Standard (GB 18918-2002), the Class A emission limits in the Integrated Water Pollutant Discharge Standard (Beijing Local Standard) (DB 11 / 307-2013) and the Class V standards in the Surface Water Environmental Quality Standard (GB 3838-2002).

[0063] Comparative Example 1

[0064] like Figure 2 As shown, a sewage deep treatment artificial wetland system, in the vertical flow artificial wetland pool, the depth of the cultivation layer 3 is 40cm, the depth of the isolation layer 4 is 10cm, the depth of the zeolite layer 5 is 40cm, the depth of the activated carbon layer 11 is 40cm, the depth of the ceramsite layer 7 is 40cm, the depth of the gravel layer 8 is 20cm; reeds and calamus are planted at a planting ratio of 1:1, and the planting density is 20-25 plants / m 2 ;

[0065] The water quality of the sewage treated by the sewage deep treatment artificial wetland system in this comparative example is the same as that in Example 1, and the effluent water quality parameters meet the Class B emission limits in the "Comprehensive Sewage Discharge Standard" (GB 18918-2002), but do not meet the Class A emission limits therein.

[0066] In summary, the present invention uses a sewage deep treatment artificial wetland system based on an ecological filter bed reinforcement material to treat practical decentralized low-carbon, high-nitrogen and phosphorus gray water in rural areas of northern China, which solves the technical problems of insufficient carbon source supply and phosphorus removal agent addition in the gray water treatment process, and through in situ [H] / H2 and Fe 2+ supply, while improving the denitrification and dephosphorization effects in cold weather. + The concentration of -N was 29.7-41.2 mg / L, the concentration of TP was 2.8-4.9 mg / L, and the concentration of NO 3- -N and NO 2- -N concentration is less than 0.1mg / L, COD concentration is 88.7-204.1mg / L, C / N ratio is 2.9-6.8, showing typical low-carbon characteristics. In a low temperature environment of -11.5 to 8.0℃, the continuous operation of the laboratory-scale activated carbon coupled artificial wetland system process and the ecological filter bed reinforcement material coupled sewage deep treatment artificial wetland system process lasted for 56 days, including microbial cultivation (36 days) and stable operation (20 days). The activated carbon and the ecological filter bed reinforcement material were filled into the electron transfer layer 6 of the system respectively. The various parameters of the water quality after treatment by the above-mentioned sewage treatment system are shown in Table 1 below.

[0067] Table 1 Water quality test indicators with different materials added

[0068] Activated carbon-constructed wetland Ecological filter bed enhancement materials-constructed wetlands COD removal rate (%) 81.6 86.17 <![CDATA[Influent NH4 + -N concentration (mg / L)]]> 36.80 36.74 <![CDATA[Effluent NH4 + -N concentration (mg / L)]]> 4.60 5.40 <![CDATA[NH4 + -N removal rate (%)]]> 87.5 85.3 <![CDATA[Effluent NO3 - -N concentration (mg / L)]]> 12.40 0.61 <![CDATA[Effluent NO2 - -N concentration (mg / L)]]> 0.93 0.30 Influent TP concentration (mg / L) 4.05 4.24 Outlet TP concentration (mg / L) 2.50 0.22 TP removal rate (%) 38.2 94.8 TN removal rate (%) 51.0 82.6

[0069] As shown in Table 1, after the ecological filter bed reinforcement material prepared by the present invention is added to the artificial wetland system to treat gray water, COD, NH4 + The removal rates of -N, TP and TN reached 86.17%, 85.3%, 94.8% and 82.6% respectively, which greatly enhanced the treatment efficiency of grey water by artificial wetland system. + -N and TP concentrations were reduced to 5.40 mg / L and 0.22 mg / L, respectively, both lower than the emission limits specified in Class A of my country's Pollutant Discharge Standard for Urban Wastewater Treatment Plants (GB 18918-2002). + -N≤8mg / L, TP≤0.5mg / L, TN≤15mg / L).

Claims

1. An ecological filter bed strengthening material, characterized in that: The raw materials of the material include electron donor, electron conductor, dephosphorization enhancer, binder and foaming agent, and the mass percentage is electron donor: electron conductor: dephosphorization enhancer: binder: foaming agent = 70-80%: 10-20%: 3-7%: 2-4%: 1-3%; the material is spherical particles, the particle size of the spherical particles is 0.5-1.0cm, and the BET specific surface area is 120-200m 2 / g, porosity 55%-70%, bulk density 0.8-1.3g / cm 3 , the bearing strength is 1.5-2.0MPa.

2. The ecological filter bed strengthening material according to claim 1, characterized in that: The electron donor is a mixture of reduced iron powder and scrap iron, the electron conductor is a mixture of powdered activated carbon and cobalt powder, the phosphorus removal enhancer is polyaluminium chloride (PAC), the binder is food grade carboxymethyl cellulose, and the foaming agent is sodium bicarbonate.

3. The ecological filter bed strengthening material according to claim 2, characterized in that: The mass ratio of the reduced iron powder to the scrap iron is (1-1.5):1, and the mass ratio of the powdered activated carbon to the cobalt powder is (800-1000):

1.

4. A method for preparing an ecological filter bed strengthening material according to any one of claims 1 to 3, characterized in that: include: The binder, foaming agent, electron donor, electron conductor and phosphorus removal enhancer are sequentially mixed, stirred, granulated, dried, and calcined at high temperature, and then naturally cooled to obtain an ecological filter bed enhancement material; By mass percentage, electron donor: electron conductor: phosphorus removal enhancer: binder: foaming agent = 70-80%: 10-20%: 3-7%: 2-4%: 1-3%.

5. The method for preparing an ecological filter bed strengthening material according to claim 4, characterized in that: The stirring speed is 90-120r / min, and the time is 20-30min; the drying temperature is 100-105°C, and the time is 3-4h; the high-temperature calcination temperature is 1000-1100°C, and the time is 2-3h; the drying, high-temperature calcination and natural cooling operations are all carried out under anaerobic conditions.

6. A sewage deep treatment artificial wetland system, characterized by: The invention comprises an ecological filter bed strengthening material as described in any one of claims 1 to 3, or an ecological filter bed strengthening material prepared by a preparation method of an ecological filter bed strengthening material as described in claim 4 or 5, and the ecological filter bed strengthening material is evenly distributed in the electron transfer layer (6) of the vertical flow artificial wetland pool.

7. The artificial wetland system for deep sewage treatment according to claim 6, characterized in that: The vertical flow artificial wetland pool further comprises a cultivation layer (3), an isolation layer (4), a zeolite layer (5), a ceramsite layer (7), and a gravel layer (8) which are laid in sequence according to the direction of water flow; the electron transfer layer (6) is located between the zeolite layer (5) and the ceramsite layer (7); and the thickness ratio of the cultivation layer (3), the isolation layer (4), the zeolite layer (5), the electron transfer layer (6), the ceramsite layer (7), and the gravel layer (8) is 4:1:4:(2-6):(2-6):

2.

8. The artificial wetland system for deep sewage treatment according to claim 7, characterized in that: The cultivation layer (3) is composed of soil and quartz sand in a volume ratio of 1:1, and is used to support vegetation growth. The particle size of the quartz sand is 0.1-1 mm. The isolation layer (4) is quartz sand with a particle size of 1-3 mm, and is used to prevent the soil of the cultivation layer (3) from penetrating downward into each layer. The zeolite layer (5) is biological zeolite with a particle size of 3-5 mm, and is used to adsorb and oxidize organic matter and ammonia nitrogen. The ceramsite layer (7) is biological ceramsite with a particle size of 8-15 mm, and is used to further remove organic matter, nitrogen and phosphorus. The gravel layer (8) is pebbles with a particle size of 15-30 mm, and serves as a drainage layer of the ecological filter bed. Reeds and calamus are planted on the cultivation layer at a planting ratio of 1:1, and the planting density is 20-25 plants / m 2 , forming a vegetation layer.

9. The artificial wetland system for deep sewage treatment according to claim 6, characterized in that: The system also comprises an inlet pool (1), the outlet pipe of the inlet pool (1) being connected to the inlet pipe of the vertical flow artificial wetland pool via a peristaltic pump (2), and the outlet pipe of the vertical flow artificial wetland pool being connected to the overflow pipe (9) via a three-way air connector (10).

10. The artificial wetland system for deep sewage treatment according to claim 6, characterized in that: The optimal operating conditions of the system in sewage treatment are: hydraulic load of 0.6-1.0m 3 / (m 2 ·d).

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