Electrode filler bioaugmentation of rural black and odorous water point source sewage treatment process

Abstract

The present application relates to the technical field of sewage treatment, and particularly discloses a rural black and odorous water point source sewage treatment process based on electrode filler biological reinforcement. The process uses a stainless steel cylindrical reactor with a heat preservation layer, a supporting layer composed of gravel and quartz sand is arranged at the bottom, active carbon fillers are filled above the supporting layer, a composite anode is embedded in the filler layer, active carbon fillers are also filled above the anode, an aeration pipe is arranged at the bottom of the upper filler area, a stainless steel mesh cathode with a surface sprayed polyaniline layer is arranged to float on the water surface and is connected to an external power supply; the composite anode is modified by transition metal and carbon co-doping to strengthen the conductivity and catalytic activity, and the active carbon fillers are modified by iron and sulfur loading, and have the functions of adsorption and autotrophic denitrification. The process couples electrode embedding and filler modification to strengthen the electron transfer efficiency, activate the free radical mediated pollutant conversion path, and simultaneously improve the removal efficiency of carbon, nitrogen, phosphorus and antibiotics, and is suitable for rural domestic sewage treatment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of sewage treatment, more particularly to a rural black and odorous water point source sewage treatment process based on electrode filler biological reinforcement. BACKGROUND

[0002] Rural black and odorous water treatment is a prominent challenge in the field of water environment in China. The pollution sources are scattered, the water quality fluctuates greatly, and the pollution characteristics of carbon, nitrogen and phosphorus are significant, and often accompanied by emerging pollutants such as antibiotics. At present, biological filter, constructed wetland, oxidation pond and other technologies are widely used in rural domestic sewage treatment. Traditional biological treatment process has inherent limitations when treating such water bodies, i.e. the metabolic activity of microorganisms is inhibited by low temperature, and the low efficiency of electron transfer leads to incomplete denitrification; heterotrophic bacteria and autotrophic bacteria compete for electron donors, resulting in imbalance of denitrification and phosphorus removal efficiency; in addition, the degradation capacity of biological method for antibiotics is limited, and it is difficult to achieve simultaneous deep removal of multiple pollutants.

[0003] Although existing electrochemical technology can strengthen the conversion of pollutants through free radical oxidation, it has problems such as high energy consumption and poor stability of electrode material when applied alone in rural areas. For example, iridium tantalum coated electrode can improve the efficiency of chlorine evolution, but its complex preparation process and dependence on noble metal lead to a substantial increase in cost, making it difficult to promote in rural decentralized treatment. Although the coupling process of biology and electrochemistry can partially overcome the above defects, most systems still have problems such as large mass transfer resistance at the interface between electrode and filler, and imperfect electron transfer chain construction. For example, in the conventional three-dimensional electrode biofilm reactor, the biofilm does not fully contact the electrode surface, resulting in low current utilization efficiency and difficulty in maintaining the dominance of hydrogen autotrophic denitrifying bacteria; autotrophic denitrifying fillers such as pyrite can provide electron donors, but their synergistic mechanism with electrodes has not been fully optimized, limiting the further improvement of denitrification and phosphorus removal efficiency.

[0004] Therefore, the present application provides a rural black and odorous water point source sewage treatment process based on electrode filler biological reinforcement to solve the above-mentioned technical problems. SUMMARY

[0005] The present application provides a rural black and odorous water point source sewage treatment process based on electrode filler biological reinforcement, which effectively solves the core problem of low electron transfer efficiency of traditional process. The process couples electrode embedding with filler modification to strengthen electron transfer efficiency, activate free radical mediated pollutant conversion path, and simultaneously improve carbon, nitrogen, phosphorus and antibiotic removal efficiency; The process structure is compact and stable in operation, and is suitable for rural domestic sewage treatment.

[0006] The present application provides a rural black and odorous water point source sewage treatment process based on electrode filler biological reinforcement, comprising the following technical solutions:

[0007] (1) In the bottom of the stainless steel cylindrical reactor with insulation layer, lay the support layer, which is composed of gravel with particle size of 5-10 mm and thickness of 5-8 cm, and quartz sand with particle size of 1-3 mm and thickness of 5-7 cm, fill the filler layer above the support layer;

[0008] (2) Embed the composite anode into the filler layer, which is filled with activated carbon filler, install the aeration pipe at the bottom of the upper filler area, set the cathode layer floating on the water surface, the cathode layer is made of stainless steel mesh, the surface of the cathode layer is sprayed with a layer of polyaniline with a thickness of 3-5 μm, and is connected to an external power supply;

[0009] (3) During operation, the aeration amount is controlled at 0.8-1.2 m³ / h, the dissolved oxygen is maintained at 2-4 mg / L, the sewage flows from the bottom, passes through the support layer, the lower filler, the composite anode, the upper filler and the cathode layer in turn, the hydraulic retention time is 8-16 h, and a direct current voltage of 0.8-1.2 V is applied.

[0010] Preferably, the preparation steps of the composite anode in step (2) are as follows:

[0011] S1, disperse the aluminum titanium carbide ceramic powder in the mixed solution, stir in a constant temperature water bath at 40-45°C for 18-24 h, then wash by centrifugation until neutral, add tetrabutylammonium hydroxide, ultrasonic for 1.4-1.6 h under nitrogen protection, and then freeze-dry to obtain functional filler;

[0012] S2, disperse the functional filler in water, add 3-(2,3-epoxypropoxy) propyl trimethoxysilane, and ultrasonic treat at 54-58°C for 40-45 min, then disperse the solid in water again after centrifugation;

[0013] S3, add 20-25 parts of mixed aqueous solution I containing cobalt nitrate hexahydrate, sodium tungstate and cerium nitrate, and 15-20 parts of mixed aqueous solution II containing ammonium hypophosphite and ammonium polyacrylate to the suspension of S2, maintain pH at 5-6, and stir at 58-62°C for 2-2.5 h to obtain a homogeneous slurry;

[0014] S4, transfer the slurry into a reaction kettle, replace with nitrogen, and react at 180-185°C for 9-11 h, then disperse the product in 1-2 M hydrochloric acid after washing and drying by centrifugation, add pyrrole, stir in an ice water bath for 26-30 min, add 0.1-0.2 M hydrochloric acid containing ferric chloride, and polymerize at 0-5°C for 6-8 h;

[0015] S5, washing and drying the product of S4, heating to 550-580℃ at 5℃ / min under argon atmosphere, heat treating for 1.5-2h, naturally cooling, vacuum drying at 120℃ for 2h, mixing with 5-8wt% polytetrafluoroethylene emulsion according to a mass ratio of (95-100):(5-8), rolling into 0.5-0.8mm thin sheets, cutting into 5x5cm mesh electrodes, sintering and curing at 280-300℃, to obtain the composite anode.

[0016] Preferably, the preparation step of the activated carbon filler in step (2) is:

[0017] A1, dispersing the activated carbon and KH550 in ethanol, stirring at 30-40℃ for 1-2h, filtering, washing and drying to obtain the modified activated carbon;

[0018] A2, dispersing the modified activated carbon, ferrous sulfate and montmorillonite in water, soaking for 12-18h, draining, adding sodium sulfide, stirring at 70-80℃ for 2-4h, washing and drying to obtain the activated carbon filler.

[0019] Preferably, in step S1, the aluminum titanium carbide ceramic powder is 15-20 parts by weight, the mixed solution is 53-60 parts by weight, and the tetrabutylammonium hydroxide is 0.8-1.2 parts by weight, and the mixed solution is composed of 50-55 parts by weight of 35-38wt% hydrochloric acid and 3-5 parts of sodium fluoride.

[0020] Preferably, in step S2, the functional filler is 15-20 parts by weight, the water is 100-110 parts by weight, and the 3-(2,3-epoxypropoxy)propyl trimethoxysilane is 0.2-0.4 parts by weight.

[0021] Preferably, in step S3, the mixed aqueous solution I is composed of 2.6-3.1 parts of cobalt nitrate hexahydrate, 1.2-1.4 parts of sodium tungstate, and 0.3-0.4 parts of cerium nitrate, and the mixed aqueous solution II is composed of 1.8-2.1 parts of ammonium hypophosphite and 0.4-0.6 parts of polyacrylamide.

[0022] Preferably, in step S4, the 1-2M hydrochloric acid is 95-100 parts by weight, the pyrrole is 0.4-0.5 parts by weight, the ferric chloride is 0.9-1.1 parts by weight, and the 0.1-0.2M hydrochloric acid is 16-20 parts by weight.

[0023] Preferably, in step A1, the activated carbon is 20-25 parts by weight, the KH550 is 4-7 parts by weight, and the ethanol is 95-100 parts by weight.

[0024] Preferably, in step A2, the modified activated carbon is 20-25 parts by weight, the ferrous sulfate is 12-18 parts by weight, the montmorillonite is 1-3 parts by weight, the water is 190-220 parts by weight, and the sodium sulfide is 6-9 parts by weight.

[0025] In summary, the present invention has the following beneficial effects:

[0026] 1. The bio-enhanced point source wastewater treatment process for black and odorous water bodies in rural areas provided by this invention constructs a highly efficient electrode-microorganism electron transfer system through a layered reactor structure with an insulation layer, an electrode embedded in the packing layer design, and the synergistic effect of a DC electric field. This process comprehensively enhances the pollutant transformation pathway, significantly improves the simultaneous removal efficiency of carbon, nitrogen, phosphorus, and antibiotics, and exhibits excellent operational stability. The composite anode, modified with transition metals and carbon co-doping, possesses both high conductivity and catalytic activity, efficiently mediating electron transfer and free radical generation. The iron-sulfur supported activated carbon packing achieves the coupling of adsorption and autotrophic denitrification functions, overcoming the electron donor limitation. The polyaniline-modified cathode enhances conductivity and stability, ensuring the synergistic effect of the electrode system.

[0027] 2. The composite anode of this invention is prepared by acid etching and stripping of aluminum titanium carbide ceramic powder, co-deposition of transition metal ions, and coating with conductive polymer. The transition metals cobalt, tungsten, and cerium doping form multiple active sites, significantly improving the yield of hydroxyl radicals and the efficiency of pollutant oxidation. The titanium nitride conductive framework and the polypyrrole coating layer synergistically enhance electron transport rate and electrode stability, avoiding dependence on precious metals. Rare earth cerium optimizes oxygen vacancy concentration and promotes interfacial charge transfer, thereby achieving highly efficient electrocatalysis under low voltage conditions, fundamentally solving the technical bottlenecks of high energy consumption and rapid catalytic activity decay in traditional anodes.

[0028] 3. The activated carbon filler of this invention is prepared by surface modification with a silane coupling agent, iron-sulfur loading, and composite with montmorillonite. The beneficial effects of this filler are that KH550 modification constructs amino anchoring sites on the activated carbon surface, significantly enhancing the binding strength of the iron-sulfur components; the reaction of ferrous sulfate and sodium sulfide produces pyrite Fe... 1-x S, through Fe 2+ / Fe 3+ With S 2- / S 0 The redox cycle drives autotrophic denitrification, simultaneously providing electron donors and phosphorus precipitation sites; the layered structure of montmorillonite regulates the slow release of iron ions, maintaining long-term denitrification efficiency while preventing biofilm blockage caused by iron dissolution, ultimately achieving the synergistic effect of adsorption, bioconversion and chemical phosphorus removal by the packing material. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the structure of the present invention.

[0030] In the diagram: 1. Stainless steel cylindrical reactor; 2. Support layer; 3. Packing layer; 4. Composite anode; 5. Aeration pipe; 6. Cathode layer. Detailed Implementation

[0031] With reference to the embodiments of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the scope of protection of the present application.

[0032] In the following examples, the experimental methods are conventional methods, and the test materials used are commercially available from conventional biochemical reagent stores, unless otherwise specified. In the quantitative tests in the following examples, three repeated experiments are set, and the data are the average value or average value ± standard deviation of the three repeated experiments.

[0033] Aluminum titanium carbide ceramic powder, purchased from Fosman Science and Technology (Beijing) Co., Ltd., CAS No. 196506-01-1;

[0034] Ammonium polyacrylate, purchased from Shanghai Yuan Ye Biological Technology Co., Ltd., item number S68736;

[0035] KH550, purchased from Shanghai Yuan Ye Biological Technology Co., Ltd., item number S15028;

[0036] Activated carbon, purchased from Wuhan Jiyue Shenghua Chemical Co., Ltd., CAS No. 7440-44-0.

[0037] Example 1

[0038] The present embodiment provides a rural black and odorous water point source sewage treatment process for electrode filler bioaugmentation, comprising the following technical solutions:

[0039] (1) A support layer 2 is laid at the bottom of a stainless steel cylindrical reactor 1 with a heat preservation layer, which is composed of gravel with a particle size of 5 mm and a thickness of 5 cm, and quartz sand with a particle size of 1 mm and a thickness of 5 cm, and activated carbon filler is filled above the support layer 2 to a height of 40 cm;

[0040] (2) The composite anode 4 is embedded in the filler layer 3 at an interval of 8 cm, activated carbon filler is filled above the anode to a height of 30 cm, an aeration pipe 5 is installed at the bottom of the upper filler area, and a cathode layer 6 is set floating on the water surface, which is made of stainless steel mesh, the surface of the cathode layer 6 is sprayed with a 3 μm polyaniline layer, and an external power supply is connected;

[0041] (3) During operation, the aeration amount is controlled at 0.8 m³ / h, the dissolved oxygen is maintained at 2 mg / L, the sewage flows from the bottom, passes through the support layer 2, the lower filler layer, the composite anode 4, the upper filler layer and the cathode layer 6 in turn, the hydraulic retention time is 8 h, and a direct current voltage of 0.8 V is applied.

[0042] The preparation steps of the composite anode 4 in step (2) are as follows:

[0043] S1, 15 parts of aluminum titanium carbide ceramic powder were dispersed in 50 parts of a mixture of 38 wt% hydrochloric acid and 3 parts of sodium fluoride, and after constant temperature water bath at 40℃ for 24h with mechanical stirring at 340rpm, washed by centrifugation until neutral, then added 0.8 parts of tetrabutylammonium hydroxide, ultrasonic treatment at 45KHz for 1.6h under nitrogen protection, and then freeze-dried to obtain a functional filler;

[0044] S2, 15 parts of functional filler were dispersed in 50 parts of water, 0.2 parts of 3-(2,3-epoxypropoxy) propyl trimethoxysilane was added, and ultrasonic treatment was carried out at 30KHz for 45min at 54℃, and then the solid was re-dispersed in 50 parts of water after centrifugation;

[0045] S3, to the suspension of S2, 20 parts of mixed aqueous solution I containing 2.6 parts of cobalt nitrate hexahydrate, 1.2 parts of sodium tungstate and 0.3 parts of cerium nitrate, and 15 parts of mixed aqueous solution II containing 1.8 parts of ammonium hypophosphite and 0.4 parts of polyacrylammonium were added dropwise, the pH was maintained at 5, and stirring was carried out at 58℃ for 2.5h at 300rpm to obtain a homogeneous slurry;

[0046] S4, the slurry was transferred into a reaction kettle, replaced with nitrogen, and reacted at 180℃ for 11h, and then the product was washed by centrifugation, dried, dispersed in 95 parts of 2M hydrochloric acid, added 0.4 parts of pyrrole, stirred at 200rpm for 30min in ice water bath, added 0.9 parts of ferric chloride in 16 parts of 0.2M hydrochloric acid dropwise, and polymerized at 5℃ for 8h;

[0047] S5, the product of S4 was washed and dried, heated to 550℃ at 5℃ / min under argon atmosphere, heat treated for 2h, naturally cooled, vacuum dried at 120℃ for 2h, mixed with 5wt% of polytetrafluoroethylene emulsion according to the mass ratio of 95:5, rolled into 0.5mm thin sheet, cut into 5×5cm mesh electrodes, sintered and solidified at 280℃ to obtain a composite anode.

[0048] The preparation steps of the activated carbon filler in step (2) are as follows:

[0049] A1, 20 parts of activated carbon and 4 parts of KH550 were dispersed in 95 parts of ethanol, stirred at 350rpm for 2h at 30℃, filtered, washed and dried to obtain modified activated carbon;

[0050] A2, 20 parts of modified activated carbon, 12 parts of ferrous sulfate and 1 part of montmorillonite were dispersed in 100 parts of water, soaked for 18h, drained, transferred into 90 parts of water, added 6 parts of sodium sulfide, stirred at 70℃ for 4h, washed and dried to obtain an activated carbon filler.

[0051] Example 2

[0052] The embodiment provides a rural black and odorous water point source sewage treatment process for electrode filler bioaugmentation, which comprises the following technical solutions:

[0053] (1) The bottom of the stainless steel cylindrical reactor 1 with insulation layer is paved with a supporting layer 2 composed of gravel with a particle size of 7 mm and a thickness of 6 cm and quartz sand with a particle size of 2 mm and a thickness of 6 cm, and the supporting layer 2 is filled with activated carbon filler to a height of 44 cm;

[0054] (2) The composite anode 4 is embedded in the filler layer 3 at an interval of 9 cm, the activated carbon filler is filled above the anode to a height of 34 cm, the aeration pipe 5 is installed at the bottom of the upper filler area, the cathode layer 6 is arranged floating on the water surface, the cathode layer 6 is made of stainless steel mesh, the surface of the cathode layer 6 is sprayed with a polyaniline layer with a thickness of 4 μm, and the external power supply is connected;

[0055] (3) During operation, the aeration amount is controlled at 0.9 m³ / h, the dissolved oxygen is maintained at 3 mg / L, the sewage flows from the bottom, passes through the supporting layer 2, the lower filler layer, the composite anode 4, the upper filler layer and the cathode layer 6 in turn, the hydraulic retention time is 9 h, and a direct current voltage of 0.9 V is applied.

[0056] The preparation steps of the composite anode 4 in step (2) are as follows:

[0057] S1, 16 parts of aluminum titanium carbide ceramic powder are dispersed in 52 parts of a mixture of 37 wt% hydrochloric acid and 4 parts of sodium fluoride, and after mechanical stirring at 42°C constant temperature water bath for 23 h at 350 rpm, washed by centrifugation until neutral, then add 0.9 parts of tetrabutylammonium hydroxide, ultrasonic at 47 KHz for 1.5 h under nitrogen protection, and then freeze-drying to obtain functional filler;

[0058] S2, 16 parts of functional filler are dispersed in 52 parts of water, 0.3 parts of 3-(2,3-epoxypropoxy) propyl trimethoxysilane is added, and ultrasonic treatment is carried out at 35 KHz for 43 min at 55°C, and after centrifugation, the solid is re-dispersed in 54 parts of water;

[0059] S3, 22 parts of mixed aqueous solution I containing 2.7 parts of cobalt nitrate hexahydrate, 1.3 parts of sodium tungstate and 0.33 parts of cerium nitrate and 17 parts of mixed aqueous solution II containing 1.9 parts of ammonium hypophosphite and 0.5 parts of polyacrylammonium are added dropwise into the suspension of S2, the pH is maintained at 5.5, and stirring is carried out at 320 rpm at 60°C for 2.4 h to obtain a homogeneous slurry;

[0060] S4, the slurry is transferred into a reaction kettle, replaced with nitrogen, and reacted at 182°C for 10 h, and then the product is washed and dried by centrifugation, dispersed in 97 parts of 1.8M hydrochloric acid, 0.44 parts of pyrrole is added, stirred at 220 rpm in ice water bath for 28 min, 1.0 parts of ferric chloride is added in 18 parts of 0.18M hydrochloric acid, and polymerized at 3°C for 7 h;

[0061] S5, the product of S4 was washed and dried, heated to 570℃ at 5℃ / min under argon atmosphere, heat-treated for 1.9h, and then naturally cooled, vacuum dried at 120℃ for 2h, mixed with 7wt% polytetrafluoroethylene emulsion at a mass ratio of 98:7, rolled into 0.6mm thin sheets, and then cut into 5×5cm mesh electrodes, which were sintered and solidified at 290℃ to obtain the composite anode.

[0062] The preparation steps of the activated carbon filler in step (2) are as follows:

[0063] A1, 22 parts of activated carbon and 5 parts of KH550 were dispersed in 98 parts of ethanol, stirred at 370 rpm at 33℃ for 1.8h, and then filtered, washed and dried to obtain modified activated carbon;

[0064] A2, 22 parts of modified activated carbon, 13 parts of ferrous sulfate and 2 parts of montmorillonite were dispersed in 105 parts of water, soaked for 17h, drained, transferred into 93 parts of water, added with 7 parts of sodium sulfide, stirred at 72℃ for 3.8h, washed and dried to obtain the activated carbon filler.

[0065] Example 3

[0066] The embodiment provides a rural black and odorous water body point source sewage treatment process for electrode filler bioaugmentation, and comprises the following technical solutions:

[0067] (1) A supporting layer 2 is laid at the bottom of a stainless steel cylindrical reactor 1 with a heat preservation layer, which is composed of gravel with a particle size of 10mm and a thickness of 8cm, and quartz sand with a particle size of 3mm and a thickness of 7cm, and the activated carbon filler is filled above the supporting layer 2 to a height of 50cm;

[0068] (2) The composite anode 4 is embedded in the filler layer 3 at an interval of 10cm, the activated carbon filler is filled above the anode to a height of 40cm, the aeration pipe 5 is installed at the bottom of the upper filler area, and the cathode layer 6 is arranged to float on the water surface, the cathode layer 6 is made of stainless steel mesh, a polyaniline layer with a thickness of 5μm is sprayed on the surface of the cathode layer 6, and an external power supply is connected;

[0069] (3) During operation, the aeration amount is controlled to be 1.2m³ / h, the dissolved oxygen is maintained at 4mg / L, the sewage flows from the bottom, passes through the supporting layer 2, the lower filler layer, the composite anode 4, the upper filler layer and the cathode layer 6 in sequence, the hydraulic retention time is 16h, and a direct current voltage of 1.2V is applied.

[0070] The preparation steps of the composite anode 4 in step (2) are as follows:

[0071] S1, 20 parts of aluminum titanium carbide ceramic powder were dispersed in a mixture of 55 parts of 35wt% hydrochloric acid and 5 parts of sodium fluoride, mechanically stirred at 380rpm in a 45℃ constant temperature water bath for 18h, washed by centrifugation until neutral, then 1.2 parts of tetrabutylammonium hydroxide was added, ultrasonicated at 55KHz under nitrogen protection for 1.4h, and then freeze-dried to obtain the functional filler;

[0072] S2, 20 parts of functional filler were dispersed in 55 parts of water, 0.4 parts of 3-(2, 3-epoxypropoxy) propyl trimethoxysilane was added, and ultrasonic treatment was carried out at 58℃ with 40KHz for 40min, and after centrifugation, the solid was redispersed in 55 parts of water;

[0073] S3, 25 parts of mixed aqueous solution I containing 3.1 parts of cobalt nitrate hexahydrate, 1.4 parts of sodium tungstate and 0.4 parts of cerium nitrate and 20 parts of mixed aqueous solution II containing 2.1 parts of ammonium hypophosphite and 0.6 parts of polyacrylammonium were added dropwise into the suspension of S2, the pH was maintained at 6, and stirring was carried out at 62℃ with 350rpm for 2h to obtain a homogeneous slurry;

[0074] S4, the slurry was transferred into a reaction kettle, replaced with nitrogen, and reacted at 185℃ for 9h, and then the product was centrifuged, washed and dried, and then dispersed in 100 parts of 1M hydrochloric acid, 0.5 parts of pyrrole was added, and stirring was carried out at 240rpm for 26min in an ice water bath, and then 20 parts of 0.1M hydrochloric acid containing 1.1 parts of ferric chloride was added dropwise, and polymerization was carried out at 0℃ for 6h;

[0075] S5, the product of S4 was washed and dried, heated to 580℃ at a rate of 5℃ / min under argon atmosphere, heat treated for 1.5h, naturally cooled, and then vacuum dried at 120℃ for 2h, and then mixed with 8wt% of polytetrafluoroethylene emulsion according to a mass ratio of 100:8, and then rolled into 0.8mm thin sheets, and then cut into 5x5cm mesh electrodes, and then sintered and solidified at 300℃ to obtain a composite anode.

[0076] The preparation steps of the activated carbon filler in step (2) are as follows:

[0077] A1, 25 parts of activated carbon and 7 parts of KH550 were dispersed in 100 parts of ethanol, stirred at 450rpm for 1h at 40℃, and then filtered, washed and dried to obtain modified activated carbon;

[0078] A2, 25 parts of modified activated carbon, 18 parts of ferrous sulfate and 3 parts of montmorillonite were dispersed in 120 parts of water, soaked for 12h, drained, and then transferred into 100 parts of water, 9 parts of sodium sulfide was added, and stirring was carried out at 80℃ for 2h, and then washed and dried to obtain activated carbon filler.

[0079] Example 4

[0080] The embodiment provides a rural black and odorous water point source sewage treatment process for electrode filler bioaugmentation, and comprises the following technical schemes:

[0081] (1) A support layer 2 is laid at the bottom of a stainless steel cylindrical reactor 1 with an insulation layer, which is composed of gravel with a particle size of 10mm and a thickness of 6cm, and quartz sand with a particle size of 2mm and a thickness of 5cm, and the activated carbon filler is filled above the support layer 2 to a height of 45cm;

[0082] (2) The composite anode 4 is embedded in the filler layer 3 at a spacing of 9 cm, the anode is filled with activated carbon filler to a height of 40 cm, an aeration pipe 5 is installed at the bottom of the upper filler area, and a cathode layer 6 is arranged floating on the water surface, the cathode layer 6 is made of stainless steel mesh, the surface of the cathode layer 6 is sprayed with a 5 μm polyaniline layer, and an external power supply is connected;

[0083] (3) During operation, the aeration amount is controlled at 1.2 m³ / h, the dissolved oxygen is maintained at 4 mg / L, the sewage flows from the bottom, passes through the support layer 2, the lower filler, the composite anode 4, the upper filler and the cathode layer 6 in turn, the hydraulic retention time is 15 h, and a direct current voltage of 1.2 V is applied.

[0084] The preparation steps of the composite anode 4 in step (2) are as follows:

[0085] S1, 20 parts of aluminum titanium carbide ceramic powder are dispersed in 55 parts of a mixture of 35 wt% hydrochloric acid and 4 parts of sodium fluoride, and after mechanical stirring at 45°C constant temperature water bath for 20 h at 380 rpm, washed by centrifugation to neutral, then 1.2 parts of tetrabutylammonium hydroxide is added, ultrasonic treatment at 50 KHz for 1.5 h under nitrogen protection, and then freeze-drying to obtain functional filler;

[0086] S2, 20 parts of functional filler are dispersed in 55 parts of water, 0.3 parts of 3-(2,3-epoxypropoxy) propyl trimethoxysilane is added, and ultrasonic treatment is carried out at 35 KHz for 40 min at 55°C, and after centrifugation, the solid is redispersed in 50 parts of water;

[0087] S3, 25 parts of mixed aqueous solution I containing 3 parts of cobalt nitrate hexahydrate, 1.3 parts of sodium tungstate and 0.4 parts of cerium nitrate, and 20 parts of mixed aqueous solution II containing 2 parts of ammonium hypophosphite and 0.5 parts of polyacrylammonium are added dropwise into the suspension of S2, the pH is maintained at 6, and stirring is carried out at 350 rpm at 60°C for 2.2 h to obtain a homogeneous slurry;

[0088] S4, the slurry is transferred into a reaction kettle, replaced with nitrogen, and reacted at 185°C for 10 h, and then the product is washed by centrifugation and drying, dispersed in 100 parts of 1.5M hydrochloric acid, 0.5 parts of pyrrole is added, stirred at 240 rpm in an ice water bath for 28 min, 20 parts of 0.18M hydrochloric acid containing 1 part of ferric chloride is added dropwise, and polymerization is carried out at 0°C for 6 h;

[0089] S5, the product of S4 is washed and dried, heated to 580°C at a rate of 5°C / min under argon atmosphere, heat treated for 1.5 h, naturally cooled, vacuum dried at 120°C for 2 h, mixed with 8 wt% polytetrafluoroethylene emulsion according to a mass ratio of 100:8, rolled into 0.8 mm thin sheets, cut into 5×5 cm mesh electrodes, sintered and solidified at 300°C, and the composite anode is obtained.

[0090] The preparation steps of the activated carbon filler in step (2) are as follows:

[0091] A1, 25 parts of activated carbon and 6 parts of KH550 were dispersed in 100 parts of ethanol, stirred at 450 rpm at 40℃ for 1.2h, and then filtered, washed and dried to obtain modified activated carbon;

[0092] A2, 25 parts of modified activated carbon, 15 parts of ferrous sulfate and 2 parts of montmorillonite were dispersed in 100 parts of water, soaked for 15h, drained, transferred into 100 parts of water, added with 8 parts of sodium sulfide, stirred at 80℃ for 2.4h, washed and dried to obtain activated carbon filler.

[0093] Comparative Example 1

[0094] A kind of electrode filler biological strengthening rural black and odorous water point source sewage treatment process, the difference between it and Example 4 is that: in the preparation of composite anode, transition metal doping and conductive polymer coating treatment are not carried out, step S2-S4 is omitted using aluminum titanium carbide ceramic powder, directly step S5 is carried out as anode material, other conditions are same with Example 4.

[0095] Comparative Example 2

[0096] A kind of electrode filler biological strengthening rural black and odorous water point source sewage treatment process, the difference between it and Example 4 is that: in the preparation of composite anode, step S1, replace aluminum titanium carbide ceramic powder with graphite powder of equal weight, subsequent steps S2-S5 are same with Example 4.

[0097] Comparative Example 3

[0098] A kind of electrode filler biological strengthening rural black and odorous water point source sewage treatment process, the difference between it and Example 4 is that: in the preparation of composite anode, step S3, replace cobalt nitrate hexahydrate and cerium nitrate in mixed aqueous solution I with equal molar amount of cobalt sulfate and cerium sulfate respectively, replace sodium tungstate with equal molar amount of sodium molybdate, other conditions are same with Example 4.

[0099] Comparative Example 4

[0100] A kind of electrode filler biological strengthening rural black and odorous water point source sewage treatment process, the difference between it and Example 4 is that: in the preparation of composite anode, omit conductive polymer coating treatment of step S4, do not carry out pyrrole polymerization, directly roll forming step S5 on the slurry heat treated product obtained in step S3, other conditions are same with Example 4.

[0101] Comparative Example 5

[0102] A kind of electrode filler biological strengthening rural black and odorous water point source sewage treatment process, the difference between it and Example 4 is that: in the preparation of activated carbon filler, only carry out silane coupling agent modification treatment of step A1, do not carry out iron and sulfur loading, directly use modified activated carbon as filler, other conditions are same with Example 4.

[0103] Comparative Example 6

[0104] A point source sewage treatment process for rural black and odorous water body bioaugmentation of electrode filler, which is different from Example 4 in that in the preparation of activated carbon filler in step A2, ferrous sulfate and sodium sulfide are replaced by equimolar amounts of ferrous chloride and sodium thiosulfate, and other conditions are the same as in Example 4.

[0105] Performance test

[0106] The self-configured water system is used as the treatment object of point source sewage of rural black and odorous water body, that is, the initial COD is 370 mg / L, ammonia nitrogen is 48 mg / L, total nitrogen is 52 mg / L, total phosphorus is 8.5 mg / L, and tetracycline is 1 mg / L. The test results are shown in Table 1.

[0107] Table 1

[0108] Test item COD removal rate Ammonia nitrogen removal rate Total nitrogen removal rate Total phosphorus removal rate Tetracycline removal rate Example 1 92.38 98.15 94.76 96.27 95.89 Example 2 93.56 98.73 95.35 97.16 96.57 Example 3 94.17 99.24 96.04 97.85 97.38 Example 4 95.65 99.52 96.83 98.44 98.16 Comparative Example 1 65.29 72.85 63.78 68.46 58.21 Comparative Example 2 72.55 80.13 70.84 75.32 62.48 Comparative Example 3 83.60 89.79 81.21 86.49 75.32 Comparative Example 4 80.41 87.20 78.52 84.11 71.64 Comparative Example 5 68.38 75.66 65.27 70.85 58.70 Comparative Example 6 76.14 83.42 73.95 79.53 66.87

[0109] The pollutant removal performance of Examples 1-4 is excellent, and the indicators of Example 4 are the best. This shows that the electrode filler bioaugmentation process of the present application effectively strengthens the electron transfer efficiency and the pollutant conversion path through the modification of the composite anode, the iron and sulfur loading treatment of the activated carbon filler, and the synergistic effect of the electrode and the filler, and achieves efficient simultaneous removal of carbon, nitrogen, phosphorus and antibiotics.

[0110] The pollutant removal rates of Comparative Examples 1-6 are significantly lower than those of the examples. Comparative Example 1 has low catalytic activity and electron conduction ability due to the absence of transition metal doping and conductive polymer coating of the composite anode, resulting in low removal rates. In Comparative Example 2, the stability of the conductive framework is insufficient after replacing the aluminum titanium carbide ceramic powder with graphite powder, which further aggravates the electrode corrosion and affects the electrochemical strengthening effect. In Comparative Example 3, the combination of transition metals is replaced by a cobalt-molybdenum system, which destroys the synergistic catalytic effect of multivalent metals and reduces the yield of hydroxyl radicals. In Comparative Example 4, the electrode and biofilm interface electron transfer efficiency is reduced due to the absence of polypyrrole conductive coating. In Comparative Example 5, the activated carbon filler lacks the electron donor and phosphorus precipitation site required for autotrophic denitrification, resulting in a significant decrease in total nitrogen and total phosphorus removal rates. This phenomenon is attributed to the lack of pyrite electron donor and insufficient abundance of denitrifying bacteria, which hinders the biological denitrification path. In Comparative Example 6, the activity of the generated iron-sulfur compounds is low after replacing the iron-sulfur source, and the biological and chemical synergistic effect of the filler is weakened, resulting in poor overall treatment performance.

[0111] The above content is merely an example and description of the present application, and those skilled in the art can make various modifications or supplements or use similar ways to replace the described specific embodiments, as long as they do not deviate from the scope of the present application or exceed the scope defined by the present claims.

Claims

1. A process for the treatment of point source wastewater from rural black and odorous water bodies by bioaugmentation of electrode fillers, characterized by, The method comprises the following steps: (1) laying a supporting layer on the bottom of a stainless steel cylindrical reactor with a heat preservation layer, wherein the supporting layer is composed of gravel and quartz sand, and a filler layer is filled above the supporting layer; (2) embedding a composite anode into the filler layer, wherein the filler layer is filled with activated carbon filler, an aeration pipe is installed at the bottom of the upper filler area, and a cathode layer is arranged floating on the water surface, wherein the cathode layer is made of a stainless steel mesh, the cathode layer is sprayed with a polyaniline layer, and is connected to an external power supply; (3) during operation, the aeration amount is controlled at 0.8-1.2 m³ / h, the dissolved oxygen is maintained at 2-4 mg / L, sewage flows from the bottom, sequentially passes through the supporting layer, the lower filler layer, the composite anode, the upper filler layer and the cathode layer, the hydraulic retention time is 8-16 h, and a direct current voltage of 0.8-1.2 V is applied; In the step (2), the preparation steps of the composite anode are as follows: S1, dispersing aluminum titanium carbide ceramic powder in a mixed solution, centrifuging and washing to neutral after constant temperature water bath stirring, adding tetrabutylammonium hydroxide, ultrasonic treatment under nitrogen protection, and obtaining functional filler by freeze-drying the obtained suspension; S2, dispersing the functional filler in water, adding 3-(2,3-epoxypropoxy) propyl trimethoxysilane, and centrifuging the obtained solid to disperse it in deionized water again; S3, adding 20-25 parts of a mixed aqueous solution I containing cobalt nitrate hexahydrate, sodium tungstate and cerium nitrate and 15-20 parts of a mixed aqueous solution II containing ammonium hypophosphite and ammonium polyacrylate to the suspension of S2, adjusting the pH value, and stirring to obtain a homogeneous slurry; S4, transferring the slurry into a reaction kettle, replacing with nitrogen, and then heat preserving and reacting, centrifuging and washing the product, and then dispersing it in 1-2 M hydrochloric acid, adding pyrrole, stirring in an ice water bath, adding 0.1-0.2 M ferric chloride hydrochloric acid solution dropwise, and polymerizing at 0-5℃; S5, washing and drying the product of S4, heat treating under argon atmosphere, naturally cooling, vacuum drying, mixing with polytetrafluoroethylene, rolling into a thin sheet, cutting into a mesh electrode, sintering and solidifying at 280-300℃, and obtaining the composite anode; In the step (2), the preparation steps of the activated carbon filler are as follows: A1, dispersing activated carbon and KH550 in ethanol, filtering, washing and drying after stirring treatment, and obtaining modified activated carbon; A2, dispersing the modified activated carbon, ferrous sulfate and montmorillonite in water, immersing, draining, transferring into water, adding sodium sulfide, stirring, washing and drying, and obtaining the activated carbon filler.

2. The electrode-filled bio-augmented rural blackish odorous water point source sewage treatment process according to claim 1, characterized in that, In the step S1, the weight parts are 15-20 parts of aluminum titanium carbide ceramic powder, 53-60 parts of mixed solution and 0.8-1.2 parts of tetrabutylammonium hydroxide, and the mixed solution is composed of 50-55 parts of 35-38 wt% hydrochloric acid and 3-5 parts of sodium fluoride.

3. The electrode-stuffed bio-augmented rural blackish odorous water point source sewage treatment process according to claim 1, characterized in that, In the step S2, the weight parts are 15-20 parts of functional filler, 100-110 parts of water and 0.2-0.4 parts of 3-(2,3-epoxypropoxy) propyl trimethoxysilane.

4. The electrode-stuffed bio-augmented rural blackish odorous water point source sewage treatment process according to claim 1, characterized in that, The mixed aqueous solution I in the step S3 is composed of 2.6-3.1 parts of cobalt nitrate hexahydrate, 1.2-1.4 parts of sodium tungstate and 0.3-0.4 parts of cerium nitrate, and the mixed aqueous solution II is composed of 1.8-2.1 parts of ammonium hypophosphite and 0.4-0.6 parts of ammonium polyacrylate.

5. The electrode-stuffed bio-augmented rural blackish odorous water point source sewage treatment process according to claim 1, characterized in that, The step S4 is 95-100 parts of 1-2M hydrochloric acid, 0.4-0.5 parts of pyrrole, 0.9-1.1 parts of ferric trichloride and 16-20 parts of 0.1-0.2M hydrochloric acid by weight.

6. The electrode-stuffed bio-augmented rural blackish odorous water point source sewage treatment process according to claim 1, characterized in that, The step A1 is 20-25 parts of activated carbon, 4-7 parts of KH550 and 95-100 parts of ethanol by weight.

7. The electrode-stuffed bio-augmented rural blackish odorous water point source sewage treatment process according to claim 1, characterized in that, The step A2 is 20-25 parts of modified activated carbon, 12-18 parts of ferrous sulfate, 1-3 parts of montmorillonite, 190-220 parts of water and 6-9 parts of sodium sulfide by weight.

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