System for improving pollution reduction and carbon reduction of constructed wetland-microbial electrolysis cell by adding fulvic acid and operation method of system

Abstract

The invention discloses a system for improving pollution reduction and carbon reduction of a constructed wetland-microbial electrolysis cell by adding fulvic acid and an operation method thereof, and belongs to the field of ecological environment governance, the system comprises a water inlet system, a purification system, a water outlet system, an adder and an intelligent detection system; the purification system comprises more than one purification unit, and different connection relations are constructed through opening and closing of valves; wastewater input from the water inlet system is discharged from the water outlet system after reaching the standard through the adsorption-electrolysis purification effect of the purification system, the intelligent detection system dynamically judges whether fulvic acid needs to be added or not and the adding amount according to the water quality condition of inlet water, meanwhile, the operation mode is accurately adjusted, the treatment effect is remarkably improved, and carbon emission is remarkably reduced. The method has the advantages of being good in treatment effect, stable in operation, convenient to operate and run and the like, particularly realizes precise dynamic addition according to different working conditions to improve the pollution and carbon reduction effect of the constructed wetland, and has the advantages of high intelligence, low carbon and greenness.

Description

Technical Field

[0001] The invention belongs to the technical field of ecological environment, and specifically relates to a method for reducing pollution and carbon emissions in an artificial wetland-microbial electrolysis cell system by adding fulvic acid. Background Art

[0002] Carbon and nitrogen emissions during water treatment have become one of the most pressing issues in the world. Studies have shown that when artificial wetlands treat sewage and wastewater, their greenhouse gas emissions per unit area are 2 to 10 times that of natural wetlands, which ultimately leads to unsatisfactory comprehensive environmental effects of artificial wetlands. Therefore, it is necessary to seek an improved method that can enhance the pollution reduction and carbon reduction capabilities of artificial wetlands. Studies have shown that artificial wetland-microbial electrolysis cell systems have higher pollutant removal efficiency than traditional artificial wetlands. However, research on artificial wetland-microbial electrolysis cell systems is still insufficient. For example, it is difficult for laboratories to fully verify their removal effects. Fulvic acid, as the main humus organic matter in urban sewage and artificial wetlands, has a lack of verification of its effect on the treatment efficiency of artificial wetland-microbial electrolysis cell systems. Therefore, a method for adding fulvic acid to improve the treatment efficiency of artificial wetland-microbial electrolysis cell systems is needed.

[0003] The patent application number CN202210057821.3, "A device and method for decarbonization and denitrification of a MEC type downward vertical flow artificial wetland with a rapid start-up microbial electrolysis cell", discloses a device and method for decarbonization and denitrification of a MEC type downward vertical flow artificial wetland with a rapid start-up microbial electrolysis cell, including an artificial wetland pool body, wherein the artificial wetland pool body is provided with a top water distribution pipe, a top non-conductive filler layer, an anode conductive filler layer, an artificial bacteria introduction pipe and an exhaust pipe, a non-conductive filler isolation layer, a cathode conductive filler layer, an artificial bacteria introduction pipe and an exhaust pipe, a bottom non-conductive filler layer and a water outlet pipe from top to bottom, wherein the anode conductive filler layer in the artificial wetland pool body is respectively connected to the top non-conductive filler layer and the non-conductive filler isolation layer, and the cathode conductive filler layer is respectively connected to the bottom non-conductive filler layer and the non-conductive filler isolation layer. However, the patent does not involve the addition of fulvic acid, let alone the effect of dynamic addition of fulvic acid on pollution reduction and carbon reduction in artificial wetlands.

[0004] The patent "Water Purification System and Method for Artificial Wetland Coupled Bioelectrochemical System" with application number CN202111311526.8 discloses a water purification system and method for an artificial wetland coupled bioelectrochemical system. The purification system includes a microbial electrolytic cell and a microbial fuel cell; the microbial electrolytic cell and the microbial fuel cell are provided with water inlets and outlets on their walls, and the outlet of the microbial electrolytic cell is connected to the outlet of the microbial fuel cell through a pipeline; a battery device is installed in the microbial electrolytic cell and the microbial fuel cell; the cathode and anode of the battery device in the microbial electrolytic cell are both arranged in the matrix, and the anode of the battery device in the microbial fuel cell is arranged in the matrix; the anode of the battery device in the microbial electrolytic cell is connected to the cathode of the battery device in the microbial fuel cell through a conductive wire; the cathode of the battery device in the microbial electrolytic cell is connected to the anode of the battery device in the microbial fuel cell through a conductive wire. However, the patent does not involve the addition of fulvic acid, let alone the effect of dynamic addition of fulvic acid on pollution reduction and carbon reduction in artificial wetlands.

[0005] The patent application number CN202210315145.5, "A sewage treatment system and a treatment method for staged sewage purification thereof", discloses a sewage treatment system and a treatment method for staged sewage purification thereof, and relates to the technical field of sewage treatment. The present invention obtains a new sewage treatment system by coupling artificial wetlands with bioelectrochemistry, and metabolizes the electrochemical microorganisms in the microbial fuel cell to convert the chemical energy of organic matter in the sewage into electrical energy, which is then transported to the microbial electrolysis cell through electrodes. The characteristic of the titanium mesh to collect electrons in a concentrated manner improves the efficiency of electron collection, thereby improving the efficiency of sewage treatment. However, the patent does not involve the addition of fulvic acid, let alone the effect of dynamic addition of fulvic acid on pollution reduction and carbon reduction in artificial wetlands. Summary of the invention

[0006] Purpose of the invention: In view of the current problem of excessive greenhouse gas emissions from artificial wetlands and the lack of effective and inexpensive improvement technologies, the present invention provides a system for reducing pollution and carbon emissions from artificial wetlands-microbial electrolysis cells by adding fulvic acid and a method for operating the system, thereby reducing greenhouse gas emissions from artificial wetlands-microbial electrolysis cells and improving the removal capacity of conventional pollutants.

[0007] Technical solution: The purpose of the present invention is achieved by the following technologies:

[0008] A system for reducing pollution and carbon emissions by adding fulvic acid to an artificial wetland-microbial electrolytic cell, comprising a water inlet system (1), a purification system (2), a water outlet system (3), a dosing device (4), and an intelligent detection system (5).

[0009] The water inlet system (1) comprises, from left to right, a water inlet pipe (1-1), a peristaltic pump (1-2), a water inlet flow meter (1-3) and a water inlet concentration detector (1-4); the purification system (2) comprises, from bottom to top, a supporting layer (2-1), an intermediate layer A (2-2), an anode layer (2-3), an intermediate layer B (2-4), a cathode layer (2-5), a gas collecting hood (2-6), a concentration detector (2-9), a valve A (2-10), a valve B (2-11), and a pressure sensor (2-12). 1); the outlet system (3) includes an outlet pipe (3-1), a valve (3-2), an outlet flow meter (3-3) and an outlet concentration detector (3-4); the intelligent detection system (5) includes an inlet module (5-1), an early warning module (5-2), a dosing module (5-3) and an outlet module (5-4) in sequence, wherein the anode layer (2-3) and the cathode layer (2-5) are respectively connected to the positive and negative electrodes of a DC power supply (2-8) through a wire (2-7). The activated sludge enters the reactor from bottom to top through the inlet pipe by a peristaltic pump, and enters the startup period after the sludge is inoculated. After the startup period ends, fulvic acid of different concentrations is added in four stages to study the effect of fulvic acid concentration on the treatment efficiency of the artificial wetland-microbial electrolysis cell system.

[0010] The supporting layer (2-1) is 10 cm thick, the middle layer A (2-2) is 7.5 cm thick, the anode layer (2-3) is 5 cm thick, the middle layer B (2-4), and the cathode layer (2-5) are 4.5 cm thick. The filling of the positive and negative electrode layers is consistent, that is, coconut shell activated carbon with a height of 5 cm and a particle size of 3-6 mm is filled, and a collector is placed in the middle.

[0011] Preferably, the activated carbon is pretreated: the coconut shell activated carbon is repeatedly washed with clean water until there is no obvious impurity. In order to activate the efficiency of the activated carbon and facilitate the subsequent enrichment of electroactive microorganisms, it is placed in 1mol / L sodium hydroxide solution and 1mol / L hydrochloric acid and soaked for 12 to 14 hours, and finally washed with deionized water until the pH of the washing solution is 7±0.2, and dried at 105°C for use.

[0012] Preferably, the carbon felt is pretreated: the cut carbon felt is immersed in an acetone aqueous solution for 12 to 14 hours to remove fat-soluble substances, and then kept in fresh boiling water, the boiling water is replaced every half an hour, and after repeating 6 times, it is dried at 105°C for use.

[0013] Preferably, the supporting layer (2-1) is filled with coarse gravel with a particle size of 10-20 mm, and the intermediate layer 1 (2-2) and the intermediate layer 2 (2-5) are filled with fine gravel with a particle size of 6-9 mm, and the gravel is unpolished gravel to enhance the biofilm formation effect of microorganisms.

[0014] Preferably, the cathode collector is cut into a ring with an inner diameter of 10 cm and an outer diameter of 15 cm, so that the upper plants can take root in the ring. The anode carbon felt is evenly punched with 9 circular holes with a diameter of about 5 mm to facilitate water flow in the anode area. The working volume of the device is 7.78 L, of which the effective volume is 3.10 L, and the overall porosity is 39.87%. Finally, the entire device is protected from light with a shade cloth (mainly including the outer wall of the device, the water inlet bucket and the water inlet pipe).

[0015] Preferably, the artificial wetland selects Iris calamus as the artificial wetland plant, and Iris calamus with similar growth status, lush plants and full tubers are selected and transplanted to the cathode areas of CW2 and ECW2.

[0016] The final wastewater contains 100 mg / L COD, 3 mg / L TP, 20 mg / L NH3-N and 12 mg / L NO3-N, so that the carbon-nitrogen ratio is about 3:1. In addition, a 10-fold diluted modified Hoagland nutrient solution (without carbon, nitrogen and phosphorus) is added to the wastewater as a source of trace elements for plant and microbial growth.

[134] , the amount added per liter of wastewater is 1mL, and it is washed into the water bucket every day.

[0017] A pollution reduction and carbon reduction system for artificial wetland-microbial electrolysis cell system by adding fulvic acid, the steps of which are as follows:

[0018] The influent concentration detector (1-4) detects the COD, TN and TP concentrations in the influent as C Ci , C Ni , C Pi , the water inlet flow meter (1-3) detects the water inlet flow Q i The effluent concentration detector (3-4) detects the COD, TN and TP concentrations in the effluent as C Ce , C Ne , C Pe , the outlet flow meter (3-3) detects the outlet flow rate Q e The concentration detector (2-9) detected the concentrations of CO2, N2O, and CH4 in the gas hood to be C CO2 , C N2O , C CH4 .

[0019] The intelligent detection system (5) performs the following operations:

[0020] 1) Calculate the influent pollution content W by formula 1 i :

[0021]

[0022] In the formula, C Ciis the COD concentration in the influent, mg / L;

[0023] C Ni is the TN concentration in the influent, mg / L;

[0024] C Pi is the TP concentration in the influent, mg / L;

[0025] K C is the conversion coefficient of pollutant COD, dimensionless;

[0026] K N is the conversion coefficient of pollutant TN, dimensionless;

[0027] K P is the conversion coefficient of pollutant TP, dimensionless;

[0028] Q i is the water inlet flow rate.

[0029] 2) Calculate the influent carbon-nitrogen ratio CN by formula 2 i :

[0030] CN i =C Ci / C Ni Formula 2

[0031] In the formula, C Ci is the COD concentration in the influent, mg / L;

[0032] C Ni is the TN concentration in the influent, mg / L;

[0033] 3) Calculate the water pollution content W through formula 3 e :

[0034]

[0035] In the formula, C Ce is the COD concentration in the effluent, mg / L;

[0036] C Ne is the TN concentration in the effluent, mg / L;

[0037] C Pe is the TP concentration in the effluent, mg / L;

[0038] K C is the conversion coefficient of pollutant COD, dimensionless;

[0039] K N is the conversion coefficient of pollutant TN, dimensionless;

[0040] K Pis the conversion coefficient of pollutant TP, dimensionless;

[0041] Q e is the water outlet flow rate, L / s.

[0042] 4) Calculate the greenhouse gas generation G by formula 4:

[0043]

[0044] In the formula, C CO2 is the volume fraction of CO2 in the gas hood, dimensionless;

[0045] C N2O is the volume fraction of N2O in the gas collection hood, dimensionless;

[0046] C CH4 is the volume fraction of CH4 in the gas collection hood, dimensionless;

[0047] V is the volume of the gas hood, m 3 ;

[0048] K CO2 , K N2O , K CH4 They are the conversion coefficients of CO2, N2O, and CH4, respectively, and are dimensionless.

[0049] The system operation is divided into the following three working conditions according to the above calculation results:

[0050] Working condition 1:

[0051] A. Wastewater is introduced into the reactor from bottom to top through the water inlet pipe (1-1) via the peristaltic pump (1-2). The intelligent detection system (5) measures the pollution content W of the inlet water. i and the influent carbon-nitrogen ratio CN i Make a judgment: When W i >W i,max , or CN i <CN i,max The input system (5-1) is fed back to the early warning system (5-2), and the purification system is adjusted by the early warning system (5-2), closing valve A (2-10) and opening valve B (2-11), so that the pool A and the pools B, C, and D are in series mode, and the pools B, C, and D are in parallel mode. The dosing module (5-3) calculates the dosage of fulvic acid for pollution reduction as W. 黄1 .

[0052] B. The wastewater then passes through the supporting layer (2-1), the intermediate layer A (2-2), and enters the anode layer (2-3), where an oxidation reaction occurs.

[0053] C. The wastewater then flows into the middle layer B (2-4), which mainly functions as a separation layer between the anode layer (2-3) and the cathode layer (2-5), and in this layer microbial treatment of the wastewater occurs.

[0054] D. The wastewater then flows into the cathode layer (2-5), where a reduction reaction occurs.

[0055] E. The outlet flow meter (3-3) and the outlet concentration detector (3-4) detect the flow and concentration of the treated water. e <W e,max When valve C (3-3) is opened, the wastewater purified by tank A flows into tanks B, C, and D through valve B (2-11), and after being treated, flows out through the outlet pipe (3-1).

[0056] F. The concentration detector (2-9) detects the concentration of greenhouse gases in the gas collection hood, and the intelligent detection system (5) determines the amount of greenhouse gases produced G: when G>G min When the greenhouse gas production of the wetland is judged to be higher than the limit, additional fulvic acid is needed for carbon reduction, and the dosage is W 黄2 .

[0057] Working condition 2:

[0058] A. Wastewater is introduced into the reactor from bottom to top through the water inlet pipe (1-1) via the peristaltic pump (1-2). The intelligent detection system (5) measures the pollution content W of the inlet water. i and the influent carbon-nitrogen ratio CN i Make a judgment: When W i,min <W i <W i,max , and CN i >CN i,max The input module (5-1) feeds back to the early warning module (5-2), and the purification system is adjusted through the early warning system (5-2), valve A (2-10) is opened, valve B (2-11) is closed, and the pools A, B, C, and D are changed to parallel mode. The dosing module (5-3) calculates the dosage of fulvic acid for pollution reduction as W. 黄1 .

[0059] B. The wastewater then passes through the supporting layer (2-1), the intermediate layer A (2-2), and enters the anode layer (2-3), where an oxidation reaction occurs.

[0060] C. The wastewater then flows into the middle layer B (2-4), which mainly functions as a separation layer between the anode layer (2-3) and the cathode layer (2-5), and in this layer microbial treatment of the wastewater occurs.

[0061] D. The wastewater then flows into the cathode layer (2-5), where a reduction reaction occurs.

[0062] E. The outlet flow meter (3-3) and the outlet concentration detector (3-4) detect the flow and concentration of the treated water. e <W e,max When valve C (3-3) is opened, wastewater enters tanks A, B, C, and D through the inlet pipe and the peristaltic pump, and after evolving through the tank, it flows out through the outlet pipe (3-1).

[0063] F. The concentration detector (2-9) detects the concentration of greenhouse gases in the gas collection hood, and the intelligent detection system (5) determines the amount of greenhouse gases produced G: when G>G min When the greenhouse gas production of the wetland is judged to be higher than the limit, additional fulvic acid is needed for carbon reduction, and the dosage is W 黄2 .

[0064] Working condition three:

[0065] A. Wastewater is introduced into the reactor from bottom to top through the water inlet pipe (1-1) via the peristaltic pump (1-2). The intelligent detection system (5) measures the pollution content W of the inlet water. i and the influent carbon-nitrogen ratio CN i Make a judgment: When W i <W i,min , and CN i >CN i,max When the input system (5-1) is fed back to the early warning system (5-2), the purification system is adjusted by the early warning system (5-2), the valve A (2-10) is opened, the valve B (2-11) is closed, and the tanks A, B, C, and D are changed to a parallel mode. The dosing module (5-3) calculates the dosage of fulvic acid for pollution reduction as Whuang 1 .

[0066] B. The wastewater then passes through the supporting layer (2-1), the intermediate layer A (2-2), and enters the anode layer (2-3), where an oxidation reaction occurs.

[0067] C. The wastewater then flows into the middle layer B (2-4), which mainly functions as a separation layer between the anode layer (2-3) and the cathode layer (2-5), and in this layer microbial treatment of the wastewater occurs.

[0068] D. The wastewater then flows into the cathode layer (2-5), where a reduction reaction occurs.

[0069] E. Then the concentration detector (3-3) performs concentration detection, and the outlet flow meter (3-3) and the outlet concentration detector (3-4) perform flow and concentration detection on the treated water. e<W e,max When valve C (3-2) is opened, wastewater enters tanks A, B, C, and D through the inlet pipe and the peristaltic pump, and after evolving through the tank, it flows out through the outlet pipe (3-1).

[0070] F. The concentration detector (2-9) detects the concentration of greenhouse gases in the gas collection hood, and the intelligent detection system (5) determines the amount of greenhouse gases produced G: when G>G min When the greenhouse gas production of the wetland is judged to be higher than the limit, additional fulvic acid is needed for carbon reduction, and the dosage is W 黄2 .

[0071] Determine the dosage of fulvic acid according to formula 5

[0072] W 黄 =W 黄1 +W 黄2 Formula 5

[0073] in,

[0074]

[0075] Where W 黄1 is the dosage of fulvic acid used for pollution reduction, mg;

[0076] W 黄2 is the dosage of fulvic acid for carbon reduction, mg;

[0077] W i is the pollutant content of the influent, mg;

[0078] W i,max is the upper limit of the influent pollution content, mg;

[0079] W i,min is the lower limit of the influent pollution content, mg;

[0080] G is the amount of greenhouse gas produced, m 3 ;

[0081] G min is the lower limit of greenhouse gas production, m 3 ;

[0082] K1 is the conversion coefficient, dimensionless.

[0083] K2 is the conversion coefficient, mg / m 3 .

[0084] Compared with the prior art, the advantages of the present invention are:

[0085] (1) The present invention uses fulvic acid as the dosing material for the artificial wetland-microorganism electrolysis cell system. The substance is a humus-like organic matter mainly present in urban sewage and artificial wetlands. By adding fulvic acid, the emission of greenhouse gases in the artificial wetland-microorganism electrolysis cell system is reduced, and the removal capacity of conventional pollutants is improved.

[0086] (2) The present invention adopts four devices connected in series and parallel, which improves the wastewater treatment effect and the treatment efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0087] Figure 1 This is a schematic diagram of the connection relationship between the artificial wetland-microbial electrolysis cell system of the present invention;

[0088] Figure 2 It is the flow chart of working condition 1;

[0089] Figure 3 This is the flow chart of working condition 2;

[0090] Figure 4 This is the flow chart for working condition three.

[0091] Among them, water inlet system-1, purification system-2, water outlet system-3, dosing device-4, intelligent detection system-5; water inlet pipe-1-1, peristaltic pump-1-2;

[0092] Inlet flow meter-1-3, outlet pipe-3-1, valve 3-2, outlet flow meter-3-3, outlet water concentration detector 3-4;

[0093] Support layer-2-1, intermediate layer A-2-2, anode layer-2-3, intermediate layer B-2-4, cathode layer-2-5, gas collecting hood-2-6, concentration detector-2-9, DC power supply-2-8. DETAILED DESCRIPTION

[0094] The technical solution of the present invention will be described in detail below in conjunction with specific embodiments:

[0095] An artificial wetland-microorganism electrolysis cell system for adding fulvic acid to improve pollution reduction and carbon reduction includes an inlet system 1, a purification system 2, an outlet system 3, a doser 4, and an intelligent detection system 5; wherein the inlet system 1, the purification system 2, and the outlet system 3 are connected in sequence, and the intelligent detection system 5 is simultaneously connected to the inlet system, the purification system, the outlet system, and the doser; the doser is connected to the purification system. Wastewater is input from bottom to top into the purification unit of the purification system through the inlet system 1, and after adsorption-microorganism electrolysis purification, it is discharged through the outlet system after purification meets the standards; during the purification process, the intelligent detection system determines the opening and closing of the valves between the purification units according to the concentration of pollutants in the wastewater to be treated, thereby constructing the connection relationship between the purification units, and at the same time determines whether fulvic acid needs to be added, and the addition amount.

[0096] The purification system 2 includes more than one purification unit, and different connection relationships are constructed by opening and closing valves; the wastewater input from the water inlet system passes through the adsorption-electrolysis purification effect of the purification system 2, and is discharged from the water outlet system after meeting the standards. The intelligent detection system 5 determines whether fulvic acid needs to be added and the amount of addition according to the water condition.

[0097] The purification unit is provided with a supporting layer 2-1, an intermediate layer A2-2, an anode layer 2-3, an intermediate layer B2-4, a cathode layer 2-5, an air collecting hood 2-6, and a concentration detector 2-9 from bottom to top; wherein, the anode layer 2-3 and the cathode layer 2-5 are respectively connected to the positive and negative poles of a DC power supply 2-8 through wires; after the start-up period, different concentrations of humic acid are added according to different water conditions.

[0098] The water inlet system 1 includes a water inlet pipe 1-1, a peristaltic pump 1-2, a flow meter 1-3 and a concentration detector from left to right; the water outlet system 3 includes a water outlet pipe 3-1, a concentration detector B3-2, and a valve C3-3. The intelligent detection system 5 is provided with a water inlet module 5-1, an early warning module 5-2, a dosing module 5-3, and a water outlet module 5-4 in sequence; wherein the water inlet module and the early warning module are connected to the water inlet system 1, the dosing module 5-3 is connected to the doser, and the doser is connected to the purification system; the water outlet module is connected to the water outlet system.

[0099] In this embodiment, the supporting layer 2-1 is 10 cm thick, the middle layer 2-2 is 7.5 cm thick, and the middle layer 2-4 is 5 cm thick. The filling material of the positive and negative electrode layers is coconut shell activated carbon, 5 cm high and 3 to 6 mm in particle size, and the collector is placed in the middle.

[0100] The filling materials of the positive and negative electrodes are pretreated before use, among which: the pretreatment of coconut shell activated carbon is to wash and dry the coconut shell activated carbon, place it in 1mol / L sodium hydroxide solution and 1mol / L hydrochloric acid for 12-14 hours to activate it, and finally wash it with deionized water until the pH of the washing solution is 7±0.2, and dry it at 105℃ for use. The pretreatment of carbon felt used as the anode collector is to place the cut carbon felt in an acetone aqueous solution to remove fat-soluble substances; then immerse it in fresh boiling water, replace the boiling water every half an hour, repeat 6 times, and dry it at 105℃ for use.

[0101] Example 1

[0102] In this embodiment, the number of purification units is four, and the connection relationship between the first purification unit to the fourth purification unit is established by opening and closing the valve A2-10 and the valve B2-11.

[0103] The specific operation process is: take four plexiglass columns with an inner diameter of 15 cm and a height of 44.5 cm, and mark them as purification units 1 to 4.

[0104] Artificially synthesized simulated secondary water was selected as the experimental wastewater (carbon-nitrogen ratio of 3:1), and 10-fold diluted Hoagland nutrient solution (removing carbon, nitrogen and phosphorus) was added to the wastewater as a source of trace elements for plant and microbial growth, with an addition amount of 1 mL per liter of wastewater.

[0105] The retrieved activated sludge was passed through a 2mm sieve to remove large particles of impurities. After repeated washing and sedimentation with clean water three times, the sludge was cultured in an anaerobic environment in the laboratory for one week, during which the nutrient solution was replaced every three days. Finally, the activated sludge and experimental simulated wastewater were mixed in a volume ratio of 1:9 and passed into the artificial wetland from bottom to top using a peristaltic pump.

[0106] The artificial wetland officially entered the startup period after inoculation with sludge. On the first day of startup, the reactor was not drained. From the second to the seventh day, half of the reactor effluent was mixed with half of the fresh wastewater and passed back to the reactor. From the eighth day, the reactor officially operated continuously with continuous upward flow, and the hydraulic load rate remained unchanged. In addition, the potential difference between the cathode and cathode was maintained at 0.8-0.9V. To achieve this goal, a voltmeter was required to be used for measurement and calibration from time to time. The entire startup period lasted for 2 months.

[0107] After the start-up period, the COD, TN and TP concentrations in the influent water detected by the influent concentration detector are C Ci，1 , C Ni,1 , C Pi,1 , the water inlet flow meter detects the water inlet flow Q i The effluent concentration detector detected the COD, TN, and TP concentrations in the effluent as C Ce，1 , C Ne,1 , C Pe,1 The intelligent detection system calculates the influent pollution content W according to formula 1. i,1 , calculate the influent carbon-nitrogen ratio CN according to formula 2 i，1 .

[0108] Intelligent detection system for influent pollution content W i,1 and the influent carbon-nitrogen ratio CN i，1 Make a judgment: Since W is satisfied i,1 >W i,max , determine the operating condition 1. The water inlet module feeds back to the early warning system, and the connection relationship of the purification units of the purification system is adjusted through the early warning system, so that the first purification unit and the second to Nth purification units are in series mode, and the second to Nth purification units are in parallel mode; the dosage of fulvic acid for pollution reduction is W 黄1 In addition, the intelligent detection system calculates the water pollution content W according to formula 3e，1 , determine whether W is satisfied e , 1 <W e,max Open the valve, and the wastewater purified by the first purification unit flows through the valve into the 2nd to Nth purification units in parallel, and after being processed again, it flows out through the outlet pipe to meet the standards.

[0109] The concentration detector detected the concentrations of CO2, N2O, and CH4 in the gas hood as C CO2，1 , C N2O,1 , C CH4,1 , calculate the greenhouse gas generation G1 through formula 4, and it is determined that G1 is satisfied <G min , the dosage of fulvic acid used for carbon reduction is 0.

[0110] Example 2

[0111] In this embodiment, after the start-up period, the influent concentration detector detects the COD, TN, and TP concentrations in the influent as C Ci，2 , C Ni,2 , C Pi,2 , the water inlet flow meter detects the water inlet flow Q i The effluent concentration detector detected the COD, TN, and TP concentrations in the effluent as C Ce，2 , C Ne,2 , C Pe,2 The intelligent detection system calculates the influent pollution content W according to formula 1. i,2 , calculate the influent carbon-nitrogen ratio CN according to formula 2 i，2 .

[0112] Intelligent detection system for influent pollution content W i,2 and the influent carbon-nitrogen ratio CN i，2 Make a judgment: Since W is satisfied i,min <W i , 2 <W i,max , and CN i,2 >CN i,max , determine the second operating condition. The water inlet module feeds back to the early warning system, and the connection relationship of the purification units of the purification system is adjusted through the early warning system to make the first to Nth purification units in parallel mode. Open valve A, close valve B and use purification units 1 to 4 in parallel to meet the water outlet standard and improve the treatment efficiency. The dosage of fulvic acid used for pollution reduction is:

[0113]

[0114] The concentration detector detected the concentrations of CO2, N2O, and CH4 in the gas hood as C CO2，2 , C N2O,2 , C CH4,2, calculate the greenhouse gas generation G2 through formula 4, and it is determined that G2 is satisfied <G min , the dosage of fulvic acid used for carbon reduction is 0.

[0115] Example 3

[0116] In this embodiment, after the start-up period, the influent concentration detector detects the COD, TN, and TP concentrations in the influent as C Ci，3 , C Ni,3 , C Pi,3 , the water inlet flow meter detects the water inlet flow Q i The effluent concentration detector detected the COD, TN, and TP concentrations in the effluent as C Ce，3 , C Ne,3 , C Pe,3 The intelligent detection system calculates the influent pollution content W according to formula 1. i,3 , calculate the influent carbon-nitrogen ratio CN according to formula 2 i，3 .

[0117] Intelligent detection system for influent pollution content W i,1 and the influent carbon-nitrogen ratio CN i,3 Make a judgment: Because the following conditions are met:

[0118] W i,3 <W i,min , and CN i,3 >CN i,max

[0119] The operating condition 3 is determined, and the water inlet module (5-1) is fed back to the early warning system (5-2). The connection relationship of the purification units of the purification system is adjusted through the early warning system (5-2), so that the first purification unit and the second to Nth purification units are in parallel mode. The dosage of fulvic acid for pollution reduction is W 黄1 is 10mg.

[0120] The concentration detector detected the concentrations of CO2, N2O, and CH4 in the gas hood as C CO2，3 , C N2O,3 , C CH4,3 , the greenhouse gas generation G3 is calculated by formula 4, and it is determined that G3>G min The dosage of fulvic acid for carbon reduction is:

[0121]

[0122] Total dosage of fulvic acid W 黄 =W 黄1 +W 黄2

[0123] Therefore, the present invention provides a method for reducing pollution and carbon emissions in an artificial wetland-microbial electrolysis cell system by adding fulvic acid, which applies fulvic acid to reduce greenhouse gas emissions from artificial wetlands, and adopts different series and parallel purification unit connections according to different conditions of the wastewater to be treated, achieving good results.

[0124] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A system for reducing pollution and carbon emissions by adding fulvic acid to an artificial wetland-microbial electrolysis cell, characterized in that: It comprises a water inlet system (1), a purification system (2), a water outlet system (3), a dosing device (4), and an intelligent detection system (5); wherein the water inlet system (1), the purification system (2), and the water outlet system (3) are connected in sequence, and the intelligent detection system (5) is simultaneously connected to the water inlet system, the purification system, the water outlet system, and the dosing device; and the dosing device is connected to the purification system; The purification system (2) includes more than one purification unit, and different connection relationships are established by opening and closing valves; the wastewater input from the water inlet system passes through the adsorption-electrolysis purification action of the purification system (2), and is discharged from the water outlet system after meeting the standards; the intelligent detection system (5) determines whether fulvic acid needs to be added and the amount of addition according to the water condition.

2. A system for reducing pollution and carbon emissions by adding fulvic acid to an artificial wetland-microbial electrolysis cell according to claim 1, characterized in that: The water inlet system (1) comprises, from left to right, a water inlet pipe (1-1), a peristaltic pump (1-2), a water inlet flow meter (1-3) and a water inlet concentration detector (1-4); the water outlet system (3) comprises a water outlet pipe (3-1), a valve (3-2), a water outlet flow meter (3-3) and a water outlet concentration detector (3-4); The number of the purification units is more than one, and two valves are provided between the first purification unit and the subsequent purification units. The first purification unit and the other purification units are connected in series or in parallel by respectively setting the opening of the valves. The purification units of the purification system (2) are provided with a supporting layer (2-1), an intermediate layer A (2-2), an anode layer (2-3), an intermediate layer B (2-4), a cathode layer (2-5), a gas collecting hood (2-6), and a concentration detector (2-9) from bottom to top. The anode layer (2-3) and the cathode layer (2-5) are respectively connected to the positive and negative electrodes of a direct current power supply (2-8) through wires. The activated sludge enters the purification system (2) from bottom to top through the water inlet pipe through a peristaltic pump, and enters a startup period after the sludge is inoculated. After the startup period ends, different concentrations of fulvic acid are added according to different water conditions. The intelligent detection system (5) is provided with a water inlet module (5-1), an early warning module (5-2), a dosing module (5-3), and a water outlet module (5-4) in sequence; wherein the water inlet module and the early warning module are connected to the water inlet system (1), the dosing module (5-3) is connected to the doser, and the doser is connected to the purification system; and the water outlet module is connected to the water outlet system.

3. The system for reducing pollution and carbon emissions by adding fulvic acid to an artificial wetland-microbial electrolysis cell according to claim 1, characterized in that: The supporting layer (2-1) is 10 cm thick and filled with coarse gravel with a particle size of 10-20 mm; The middle layer (2-2) is 7.5 cm thick and filled with fine gravel with a particle size of 6–9 mm; The filling material of the middle layer (2-4) of the cathode and anode electrodes is coconut shell activated carbon, 5 cm high and 3-6 mm in diameter, and a collector is placed in the middle; the anode collector is carbon felt and the cathode collector is ring-shaped; The purification unit is protected from light as a whole, and plants are planted on the top.

4. The system for reducing pollution and carbon emissions by adding fulvic acid to an artificial wetland-microbial electrolysis cell according to claim 3, characterized in that: The filling materials of the cathode and anode electrodes are pre-treated before use, including: The pretreatment of coconut shell activated carbon is to wash and dry the coconut shell activated carbon, place it in 1mol / L sodium hydroxide solution and 1mol / L hydrochloric acid for 12-14h activation, and finally wash it with deionized water until the pH of the washing solution is 7±0.2, and dry it at 105℃ for use; The carbon felt pretreatment is to place the cut carbon felt in an acetone aqueous solution to remove fat-soluble substances; then immerse it in fresh boiling water, replace the boiling water every half an hour, repeat 6 times, and then dry it at 105°C for use.

5. The method for operating a system for reducing pollution and carbon emissions by adding fulvic acid to an artificial wetland-microbial electrolysis cell according to claim 1, characterized in that: Wastewater is input from bottom to top into the purification unit of the purification system through the water inlet system (1), and after being purified by adsorption-microorganism electrolysis, it is discharged through the water outlet system after the purification reaches the standard. During the purification process, the intelligent detection system determines the opening and closing of the valves between the purification units according to the concentration of pollutants in the wastewater to be treated, thereby establishing the connection relationship between the purification units, and at the same time determines whether fulvic acid needs to be added, and the amount of addition.

6. The method for operating a system for reducing pollution and carbon emissions by adding fulvic acid to an artificial wetland-microbial electrolysis cell according to claim 5, characterized in that: The influent concentration detector (1-4) detects the COD, TN and TP concentrations in the influent as C Ci , C Ni , C Pi , the water inlet flow meter (1-3) detects the water inlet flow Q i The effluent concentration detector (3-4) detects the COD, TN, and TP concentrations in the effluent as C Ce , C Ne , C Pe , the outlet flow meter (3-3) detects the outlet flow rate Q e The concentration detector (2-9) detects the concentrations of CO2, N2O, and CH4 in the gas hood and is C CO2 , C N2O , C CH4 ; The intelligent detection system (5) performs the following calculations based on the above detection data: 1) Calculate the influent pollution content W by formula 1 i : In the formula, C Ci is the COD concentration in the influent, mg / L; C Ni is the TN concentration in the influent, mg / L; C Pi is the TP concentration in the influent, mg / L; K C is the conversion coefficient of pollutant COD, dimensionless; K N is the conversion coefficient of pollutant TN, dimensionless; K P is the conversion coefficient of pollutant TP, dimensionless; Q i is the inlet flow rate; 2) Calculate the inlet carbon-nitrogen ratio CN by formula 2 i : CN i = C Ci / C Ni Formula 2 In the formula, C Ci is the COD concentration in the influent, mg / L; C Ni is the TN concentration in the influent, mg / L; 3) Calculate the water pollution content W through formula 3 e : In the formula, C Ce is the COD concentration in the effluent, mg / L; C Ne is the TN concentration in the effluent, mg / L; C Pe is the TP concentration in the effluent, mg / L; K C is the conversion coefficient of pollutant COD, dimensionless; K N is the conversion coefficient of pollutant TN, dimensionless; K P is the conversion coefficient of pollutant TP, dimensionless; Q e is the water outlet flow rate, L / s. 4) Calculate the greenhouse gas generation G by formula 4: In the formula, C CO2 is the volume fraction of CO2 in the gas hood, dimensionless; C N2O is the volume fraction of N2O in the gas collection hood, dimensionless; C CH4 is the volume fraction of CH4 in the gas collection hood, dimensionless; V is the volume of the gas hood, m 3 ; K CO2 , K N2O , K CH4 They are the conversion coefficients of CO2, N2O, and CH4, respectively, and are dimensionless.

7. The method for operating a system for reducing pollution and carbon emissions by adding fulvic acid to an artificial wetland-microbial electrolysis cell according to claim 6, characterized in that: There are three working conditions: Working condition 1: (1) Wastewater enters the water inlet system from the water inlet pipe (1-1) through the peristaltic pump (1-2). The intelligent detection system (5) measures the pollution content W of the inlet water. i and the influent carbon-nitrogen ratio CN i Make a judgment: When W i >W i,max , or CN i <CN i,max Then, the water inlet module (5-1) is fed back to the early warning system (5-2), and the connection relationship of the purification units of the purification system is adjusted through the early warning system (5-2), so that the first purification unit and the second to Nth purification units are in series mode, and the second to Nth purification units are in parallel mode; the addition module (5-3) calculates the addition amount of fulvic acid for pollution reduction as W 黄1 ; (2) In the first purification unit, the wastewater flows from bottom to top in an overflow mode through the support layer (2-1), the intermediate layer A (2-2), and enters the anode layer (2-3), where an oxidation reaction occurs; microorganisms treat the wastewater in the intermediate layer B (2-4), which is a separation layer between the anode layer (2-3) and the cathode layer (2-5); and flows into the cathode layer (2-5), where a reduction reaction occurs; (3) The outlet water flow meter (3-3) and the outlet water concentration detector (3-4) detect the flow and concentration of the treated water. e <W e,max When the valve (3-3) is opened, the wastewater purified by the first purification unit flows through the valve into the 2nd to Nth purification units in parallel, and after being processed again, flows out through the outlet pipe (3-1) to meet the standards, wherein; (4) The concentration detector (2-9) detects the concentration of greenhouse gases in the gas collection hood, and the intelligent detection system (5) determines the amount of greenhouse gases produced G: when G>G min When the greenhouse gas production of the wetland is judged to be higher than the limit, additional fulvic acid is needed for carbon reduction, and the dosage is W 黄2 ; Working condition 2: (1) Intelligent detection system (5) for the influent pollution content W i and the influent carbon-nitrogen ratio CN i Make a judgment: When W i,min <W i <W i,max , and CN i >CN i,max The water inlet module (5-1) is fed back to the early warning system (5-2), and the connection relationship of the purification units of the purification system is adjusted by the early warning system (5-2), so that the first to Nth purification units are in parallel mode, and the addition module (5-3) calculates the addition amount of fulvic acid for pollution reduction as W 黄1 ; (2) In the first to Nth purification units, the wastewater flows from bottom to top in an overflow mode through the support layer (2-1), the intermediate layer A (2-2), and enters the anode layer (2-3), where an oxidation reaction occurs; microorganisms treat the wastewater in the intermediate layer B (2-4), which is a separation layer between the anode layer (2-3) and the cathode layer (2-5); and flows into the cathode layer (2-5), where a reduction reaction occurs; (3) The outlet water flow meter (3-3) and the outlet water concentration detector (3-4) detect the flow and concentration of the treated water. e <W e,max When the valve (3-3) is opened, the standard flow is achieved; (4) The concentration detector (2-9) detects the concentration of greenhouse gases in the gas collection hood, and the intelligent detection system (5) determines the amount of greenhouse gases produced G: when G>G min When the greenhouse gas production of the wetland is judged to be higher than the limit, additional fulvic acid is needed for carbon reduction, and the dosage is W 黄2 . Working condition three: (1) Intelligent detection system (5) for the influent pollution content W i and the influent carbon-nitrogen ratio CN i Make a judgment: When W i <W i,min , and CN i >CN i,max Then, the water inlet module (5-1) is fed back to the early warning system (5-2), and the connection relationship of the purification units of the purification system is adjusted through the early warning system (5-2), so that the first purification unit and the second to Nth purification units are in parallel mode; the addition module (5-3) calculates the addition amount of fulvic acid for pollution reduction as W 黄1 ; (2) In the first to Nth purification units, the wastewater flows from bottom to top in an overflow mode through the support layer (2-1), the intermediate layer A (2-2), and enters the anode layer (2-3), where an oxidation reaction occurs; microorganisms treat the wastewater in the intermediate layer B (2-4), which is a separation layer between the anode layer (2-3) and the cathode layer (2-5); and flows into the cathode layer (2-5), where a reduction reaction occurs; (3) The outlet water flow meter (3-3) and the outlet water concentration detector (3-4) detect the flow and concentration of the treated water. e <W e,max When the valve (3-3) is opened, the standard flow is achieved; (4) The concentration detector (2-9) detects the concentration of greenhouse gases in the gas collection hood, and the intelligent detection system (5) determines the amount of greenhouse gases produced G: when G>G min When the greenhouse gas production of the wetland is judged to be higher than the limit, additional fulvic acid is needed for carbon reduction, and the dosage is W 黄2 .

8. The method for operating a system for reducing pollution and carbon emissions by adding fulvic acid to an artificial wetland-microbial electrolysis cell according to claim 7, characterized in that: Determine the dosage of fulvic acid according to formula 5 W 黄 = W 黄1 + W 黄2 Equation 5 in, Where W 黄1 is the dosage of fulvic acid used for pollution reduction, mg; W 黄2 is the dosage of fulvic acid for carbon reduction, mg; W i is the pollutant content of the influent, mg; W i,max is the upper limit of the influent pollution content, mg; W i,min is the lower limit of the influent pollution content, mg; G is the amount of greenhouse gas produced, m 3 ; G min is the lower limit of greenhouse gas production, m 3 ; K1 is the conversion coefficient, dimensionless. K2 is the conversion coefficient, mg / m 3 .

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