Distributed biological membrane low-temperature sewage treatment device and method based on Joule heating effect and carrier adsorption

Abstract

The invention relates to a distributed biological membrane low-temperature sewage treatment device based on a Joule heating effect and carrier adsorption. The distributed biological membrane low-temperature sewage treatment device mainly comprises a reactor main body, an electric heating membrane assembly, an aeration system and a reflux adjusting module, a water inlet and a water outlet are respectively formed in the left side and the right side of the reactor main body, and a plurality of baffle plates are arranged in the reactor main body to divide the reactor main body into an anaerobic zone, an anoxic zone, an aerobic zone I, an aerobic zone II and a vertical flow secondary sedimentation tank. The electric heating wire is arranged in the center of the biofilm carrier for low-power and continuous heating, so that the biofilm carrier has lower operation energy consumption, higher heat transfer efficiency and more uniform temperature distribution. An internal heating mode that the electric heating wires are uniformly arranged in the tank body can be used for carrying out centralized heating on an area in which a biological membrane is positioned, generating local high temperature on the surface of the filler and an area nearby the filler, improving the activity of microorganisms growing on the surface of the filler, increasing the biochemical treatment rate and effect, avoiding global heating of sewage in the tank body and reducing the heating energy consumption.

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment equipment, and particularly relates to a decentralized biofilm low-temperature sewage treatment device and method based on the Joule heat effect and carrier adsorption. Background Art

[0002] In winter in northern China, the temperature is relatively low, the sewage water temperature is lower than 15°C, and in some areas, the water temperature can be as low as 4°C in extremely cold weather. There are also low-temperature impacts brought by snowmelt and cold air outbreaks. Due to the low temperature, most of the microorganisms in the sewage are in a dormant state, and the biodegradation effect is strongly inhibited. When the temperature is lower than 15°C, biological nitrification is significantly inhibited, and when the temperature is lower than 4°C, nitrifying bacteria almost completely lose their activity. When the temperature is lower than 10°C, the denitrification rate decreases significantly, and when it is lower than 3°C, the denitrification basically stops. In terms of phosphorus removal, low temperature will affect the phosphorus uptake and release rates of polyphosphate-accumulating bacteria. In practical applications, it is difficult to start the phosphorus removal process under low-temperature conditions, and the phosphorus removal efficiency decreases. The reduction of microbial activity at low temperature significantly reduces the pollutant removal rate of decentralized domestic sewage treatment facilities, resulting in unsatisfactory treatment effects.

[0003] Currently, the main strengthening measures for low-temperature domestic sewage treatment include extending the sludge age, adding nutrients, adding strains, etc. However, the above measures only have short-term effects and increase sludge production. The sewage heating technology can improve the microbial activity in the sewage by raising the sewage temperature, and fundamentally solve the problem of low-temperature sewage treatment. The electric heating technology is considered a simple, practical and effective technical measure with relatively low construction costs and easy implementation, and has been widely used in low-temperature sewage treatment facilities. Currently, the electric heating technology is often arranged in the form of winding electric heating tapes on the outer wall or installing heating rods inside, which has the disadvantages of uneven heating, large heat loss and high energy consumption.

[0004] In view of the above problems, there is an urgent need for a new type of biofilm sewage treatment device to improve the operation stability of decentralized sewage treatment facilities and the sewage treatment effect under low-temperature conditions. Summary of the Invention

[0005] The present invention aims to solve the technical problems of uneven temperature distribution, large heat loss and limited heat transfer effect in the existing low-temperature sewage electric heating system, resulting in poor heating effect, and provides a decentralized biofilm low-temperature sewage treatment device and method based on the Joule heat effect and carrier adsorption.

[0006] The technical solution adopted by the present invention to solve the above problems is:

[0007] A decentralized biofilm low-temperature sewage treatment device based on the Joule heat effect and carrier adsorption mainly includes a reactor main body 1, an electric heating film assembly 2, an aeration system 4 and a reflux adjustment module 9;

[0008] On the left and right sides of the reactor main body 1, a water inlet 1-1 and a water outlet 1-2 are respectively arranged. Inside the reactor main body 1, a plurality of baffle plates are arranged, dividing the reactor main body 1 into an anaerobic zone 1-3, an anoxic zone 1-4, an aerobic zone I 1-5, an aerobic zone II 1-6, and a vertical flow secondary sedimentation tank 1-7;

[0009] The electric heating biofilm assembly 2 is arranged in the reactor main body 1. An elastic biological filler 2-2 is spirally wound around the electric heating wire 2-1 and is connected in parallel to a voltage regulating power supply 2-4 by a waterproof wire 2-3;

[0010] The aeration system 4 includes a blower 4-1, an aeration pipeline 4-2, and a microporous aeration pipe 4-3; the blower 4-1 is connected to the microporous aeration pipe 4-3 through the aeration pipeline 4-2; the aeration pipeline 4-3 is fixed at the bottom of the reactor main body 1, and the microporous aeration pipe 4-3 is installed in the reactor main body 1 through the aeration pipeline 4-2;

[0011] The reflux regulation module 9 includes a reflux pipeline 9-1, one end of which is communicated with the aerobic zone II 1-6, and the other end is communicated with the anoxic zone 1-4; a reflux pump 9-2 is arranged on the reflux pipeline 9-1 for transporting liquid from one end of the reflux pipeline 9-1 to the other end; a reflux valve 9-3 is used to control the opening and closing of the reflux pipeline 9-1.

[0012] Furthermore, a thermometer access port 1-8 is arranged at the top of the reactor main body 1; the thermometer 3 is arranged in the reactor main body 1 through the thermometer access port 1-8; the digital display control box 7 is connected to the thermometer 3, and the real-time temperature data is monitored through the digital display control box 7.

[0013] Furthermore, a heat preservation layer 8 is fixed on the outer side of the reactor main body 1; the water inlet pipe 5 is connected to the reactor main body 1 through the water inlet 1-1; the drain pipe 6 is connected to the reactor main body 1 through the water outlet 1-2.

[0014] Furthermore, the electric heating wire 2-1 is a multi-strand nickel-chromium wire wrapped with silica gel, Φ = 2.5mm, and the resistance value is 100Ω / m.

[0015] Furthermore, the elastic biological filler is a snowflake-shaped aldehydeized fiber branch, the unit diameter Φ = 100mm, and the mass density is 3.1kg / m 3 , the arrangement spacing is 60mm, and the filling rate is 60-80%.

[0016] Furthermore, the heat preservation layer 8 is a polyurethane heat preservation board, with a thickness of 5cm and a thermal conductivity of 0.018-0.024W / (m·K).

[0017] Furthermore, a maintenance opening and an exhaust hole are provided at its top. A cover door is arranged at the top end of the maintenance opening, and a one-way valve is arranged on the exhaust hole. An overflow pipe is connected to the rear side of the main sewage treatment device. A drain pipe is connected to the bottom of the rear side of the main sewage treatment device. The overflow pipe and the drain pipe converge into a main pipe. A detection port is opened at the bottom of the front side of the main sewage treatment device, and the detection port is opened and closed by a valve.

[0018] The present invention also relates to a sewage treatment method, which applies the above-mentioned decentralized biofilm low-temperature sewage treatment device based on the Joule heat effect and carrier adsorption, and includes the following steps:

[0019] Step 1. Start under low-temperature conditions: Install the electro-heated biofilm components 2 in the anaerobic zone 1-3, anoxic zone 1-4, aerobic zone I 1-5, and aerobic zone II 1-6. Use the influent submersible pump to pump the domestic sewage to be treated into the device through the influent port 1-1, and add excess sludge.

[0020] Turn on the voltage regulating power supply 2-4 and the digital display control box 7 of the electro-heated biofilm component 2. After the thermometer 3 converts the temperature data into an electrical signal and transmits it to the digital display control box 7, the digital display control box 7 outputs a control signal to the voltage regulating power supply 2-4 according to the built-in mathematical model to adjust the voltage, so as to ensure the heating power of the heating wire 2-1. After the heating wire 2-1 is started, heat the water layer around the heating wire 2-1 and the elastic biological filler 2-2.

[0021] The biochemical process is started by the delayed sludge discharge method. The inoculated sludge is pumped into the equipment and mixed with the sewage. The mixture is aerated for 1-2 days to make the sludge fully contact with the elastic biological filler. After 1-2 days, it is allowed to settle for 0.5 h, and the supernatant is discharged. Then, the sewage is pumped in again, and the continuous influent and effluent are carried out at 10-20% of the designed flow rate. When a biofilm adheres to the surface of the filler, the influent flow rate is adjusted to 50% of the designed flow rate. When the effluent quality reaches the standard, the influent flow rate is adjusted to the designed flow rate.

[0022] Step 2. Stable operation under low-temperature conditions: The domestic sewage to be treated is pumped into the anaerobic zone 1-3 through the influent port 1-1, and then flows through the baffle plate and into the anoxic zone 1-4, aerobic zone I 1-5, and aerobic zone II 1-6 in turn. The sewage fully contacts the biological film attached to the heating wire 2-1 and the membrane component 2-2, so as to achieve pollutant removal.

[0023] Through the reflux pump 9-2, the nitrified liquid in the aerobic zone II 1-6 is refluxed to the anoxic zone 1-4 through the reflux pipeline 9-1 for the removal of nitrate nitrogen; after the sewage treated biologically is precipitated in the vertical flow secondary sedimentation tank 1-7, it is discharged from the water outlet 1-2, and the excess sludge generated is discharged through the sludge discharge pipe at the bottom of the vertical flow secondary sedimentation tank 1-7. During operation, the voltage regulating power supply 2-4 and the digital display control box 7 of the electrothermal biofilm module 2 are turned on. After the thermometer 3 converts the temperature data into an electrical signal and transmits it to the digital display control box 7, the digital display control box 7 outputs a control signal to the voltage regulating power supply 2-4 according to the built-in mathematical model to adjust the voltage and ensure the heating power of the electrothermal wire 2-1; after the electrothermal wire 2-1 is started, the water layer around the electrothermal wire 2-1 and the elastic biological filler 2-2 is heated to ensure the heat demand of the microorganisms in the pool and improve the activity of the microorganisms.

[0024] Further, the process operation parameters in step one are as follows: the hydraulic retention time in the anaerobic zone 1-3 and the anoxic zone 1-4 is 3-5 h; the filling rate of the elastic biological filler 2-2 in the anaerobic zone 1-3, the anoxic zone 1-4, the aerobic zone I 1-5 and the aerobic zone II 1-6 is 60-80%; the hydraulic retention time in the aerobic zone I 1-5 and the aerobic zone II 1-6 is 6-10 h, the biological film loading on the surface of the elastic biological filler is 3-5 g MLSS / g, the reflux ratio is 100% - 200%, the dissolved oxygen in the anaerobic zone 1-3 is 0-0.2 mg / L, the dissolved oxygen in the anoxic zone 1-4 is 0.2 - 0.5 mg / L, the dissolved oxygen in the aerobic zone I 1-5 and the aerobic zone II 1-6 is 2-4 mg / L, and the temperature of the water layer around the electrothermal wire 2-1 and the elastic biological filler 2-2 is between 9-17 °C.

[0025] Further, during the treatment process in step two, the hydraulic retention time in the anaerobic zone 1-3 and the anoxic zone 1-4 is 3-5 h; it is controlled that the hydraulic retention time in the aerobic zone I 1-5 and the aerobic zone II 1-6 is 6-10 h, the biological film loading on the surface of the elastic biological filler is 3-5 g MLSS / g, the reflux ratio is 50% - 100%, the dissolved oxygen in the anaerobic zone 1-3 is 0-0.2 mg / L, the dissolved oxygen in the anoxic zone 1-4 is 0.2-0.5 mg / L, the dissolved oxygen in the aerobic zone I 1-5 and the aerobic zone II 1-6 is 2-4 mg / L; the working voltage of the voltage regulating power supply 2-4 is 6-12 V, and the corresponding heating power is 14.4-57.6 W; the working voltage of the voltage regulating power supply 2-4 will gradually increase with the decrease of the influent water temperature to ensure that the temperature of the water layer around the electrothermal wire 2-1 and the elastic biological filler 2-2 is between 9-17 °C.

[0026] Beneficial effects

[0027] In the decentralized biofilm low-temperature sewage treatment facility of the present invention, the outer layer of the electric heating wire in the electric heating system is wrapped by silica gel, which has good biocompatibility. When a biofilm is loaded on the surface of the electric heating wire, heat is transferred layer by layer from the inner side of the biofilm to the outer side of the biofilm by the electric heating wire, meeting the temperature requirements of the anaerobic layer - anoxic layer - aerobic layer of the biofilm. In addition, the electric heating wire is fixed at the center of the bio-elastic filler, and a temperature distribution gradually decreasing radially outward from the heating wire can be formed, which not only helps to reduce heat loss, but also enables the biofilm carriers in different temperature layers to enrich microorganisms adapted to different temperatures. By increasing the species richness in the system, the low-temperature sewage treatment effect of the system and the ability to resist low-temperature shock loads are enhanced.

[0028] The present invention conducts small-power and continuous heating by arranging an electric heating wire at the center of the biofilm carrier, and has lower operating energy consumption, higher heat transfer efficiency, and more uniform temperature distribution. The internal heating mode with the electric heating wire evenly placed inside the pool body can centrally heat the area where the biofilm is located, generate local high temperatures on the surface of the filler and in the nearby areas, enhance the activity of microorganisms growing on the surface of the filler, and increase the biochemical treatment rate and effect. Avoid globally heating the sewage in the pool body and reduce heating energy consumption; the heat generated by the electric heating wire is directly transferred to the water layer where the biofilm and the elastic biofiller are located, avoiding heat loss generated during the heat transfer process from the pool wall to the inside of the pool; the internal heating mode can form a temperature distribution gradually decreasing from the inside to the outside in the pool body, form different temperature regions around the filler, enable the surface of the filler to enrich microorganisms with different optimal temperatures, increase the species richness in the pool, and enhance the low-temperature operation stability of the system and the ability to resist low-temperature shock loads; the temperature distribution gradually decreasing from the inside to the outside can also reduce the temperature difference between the sewage in the pool body and the external environment, thereby reducing the heat exchange between the pool body and the environment and reducing heat loss.

[0029] The decentralized biofilm low-temperature sewage treatment device of the present invention can be used in the field of low-temperature sewage treatment, especially in cold regions where the sewage temperature is low in spring and winter and low-temperature shock loads are frequent. Description of the Drawings

[0030] Figure 1 is a schematic structural diagram of the decentralized biofilm low-temperature sewage treatment device based on the Joule heat effect and carrier adsorption of the present invention;

[0031] Figure 2 is Figure 1 the schematic cross-sectional view A-A in, and is a schematic structural diagram of the electric heating biofilm assembly 2 of the present invention;

[0032] Figure 3 is a schematic circuit diagram of the electric heating biofilm assembly 2 of the present invention;

[0033] Figure 4 is the influent and effluent pollutant concentrations during the treatment of low-temperature sewage in three embodiments of the present invention.

[0034] Description of Reference Numerals

[0035] 1 is the reactor main body, 1-1 is the water inlet, 1-2 is the water outlet, 1-3 is the anaerobic zone, 1-4 is the anoxic zone, 1-5 is the aerobic zone I, 1-6 is the aerobic zone II, 1-7 is the vertical flow secondary sedimentation tank, 1-8 is the thermometer connection port, 2 is the electric heating biofilm assembly, 2-1 is the electric heating wire, 2-2 is the elastic biological filler, 2-3 is the waterproof wire, 2-4 is the voltage regulating power supply, 3 is the thermometer, 4 is the aeration system, 4-1 is the blower, 4-2 is the aeration pipe, 4-3 is the microporous aeration pipe, 5 is the water inlet pipe, 6 is the water outlet pipe, 7 is the digital display control box, 8 is the thermal insulation layer, 9 is the reflux regulation module, 9-1 is the reflux pipeline, 9-2 is the reflux pump, 9-3 is the reflux valve. Specific Embodiment

[0036] The technical solution of the present invention will be specifically described below.

[0037] The decentralized biofilm low-temperature sewage treatment device based on the Joule heat effect and carrier adsorption of the present invention mainly includes a reactor main body 1, an electric heating membrane assembly 2, an aeration system 4, and a reflux regulation module 9;

[0038] The water inlet 1-1 and the water outlet 1-2 are respectively arranged on the left and right sides of the reactor main body 1. A plurality of baffle plates are arranged inside the reactor main body 1 to divide the reactor main body 1 into an anaerobic zone 1-3, an anoxic zone 1-4, an aerobic zone I 1-5, an aerobic zone II 1-6, and a vertical flow secondary sedimentation tank 1-7; the electric heating biofilm assembly 2 is arranged in the reactor main body 1, the elastic biological filler 2-2 is spirally wound on the electric heating wire 2-1, and is connected in parallel to the voltage regulating power supply 2-4 by the waterproof wire 2-3; the aeration system 4 includes a blower 4-1, an aeration pipe 4-2, and a microporous aeration pipe 4-3; the blower 4-1 is connected to the microporous aeration pipe 4-3 through the aeration pipe 4-2; the aeration pipe 4-3 is fixed to the bottom of the reactor main body 1, and the microporous aeration pipe 4-3 is installed in the reactor main body 1 through the aeration pipe 4-2; the reflux regulation module 9 includes a reflux pipeline 9-1, one end of which is communicated with the aerobic zone II 1-6 and the other end is communicated with the anoxic zone 1-4; a reflux pump 9-2 is arranged on the reflux pipeline 9-1 for transporting the liquid from one end of the reflux pipeline 9-1 to the other end; a reflux valve 9-3 is used to control the opening and closing of the reflux pipeline 9-1.

[0039] A thermometer connection port 1-8 is arranged at the top of the reactor main body 1; the thermometer 3 is arranged in the reactor main body 1 through the thermometer connection port 1-8; the digital display control box 7 is connected to the thermometer 3, and the real-time temperature data is monitored through the digital display control box 7. The thermal insulation layer 8 is fixed to the outside of the reactor main body 1; the water inlet pipe 5 is connected to the reactor main body 1 through the water inlet 1-1; the drain pipe 6 is connected to the reactor main body 1 through the water outlet 1-2.

[0040] Preferably, the electric heating wire 2-1 is a multi-strand nickel-chromium wire wrapped with silica gel, with Φ = 2.5 mm and a resistance value of 100 Ω / m. The elastic biological filler is snowflake-shaped aldehydeized fiber branches, with a unit diameter of Φ = 100 mm and a mass density of 3.1 kg / m 3 , and the arrangement spacing is 60 mm, and the filling rate is 60-80%.

[0041] Preferably, the thermal insulation layer 8 is a polyurethane thermal insulation board with a thickness of 5 cm and a thermal conductivity of 0.018-0.024 W / (m·K).

[0042] The decentralized biofilm low-temperature sewage treatment device of the present invention is provided with a maintenance opening and an exhaust hole at the top. A cover door is provided at the top of the maintenance opening, and a one-way valve is provided on the exhaust hole; an overflow pipe is connected to the rear side of the sewage treatment main device; a drain pipe is connected to the bottom of the rear side of the sewage treatment main device, and the overflow pipe and the drain pipe converge into a main pipe; a detection port is opened at the bottom of the front side of the sewage treatment main device, and the detection port is opened and closed through a valve.

[0043] The present invention also relates to a sewage treatment method, which uses the above-mentioned decentralized biofilm low-temperature sewage treatment device based on the Joule heat effect and carrier adsorption, and includes the following steps:

[0044] Step 1: Start under low-temperature conditions: Install the electric heating biofilm assembly 2 in the anaerobic zone 1-3, anoxic zone 1-4, aerobic zone I 1-5, and aerobic zone II 1-6. Pump the domestic sewage to be treated through the water inlet 1-1 with an inlet submersible pump, and add excess sludge;

[0045] Turn on the voltage regulating power supply 2-4 and the digital display control box 7 of the electric heating biofilm assembly 2. After the thermometer 3 converts the temperature data into an electrical signal and transmits it to the digital display control box 7, the digital display control box 7 outputs a control signal to the voltage regulating power supply 2-4 to adjust the voltage according to the built-in mathematical model to ensure the heating power of the electric heating wire 2-1; after the electric heating wire 2-1 is started, heat the water layer around the electric heating wire 2-1 and the elastic biological filler 2-2;

[0046] The biochemical process is started by the delayed sludge discharge method. The inoculated sludge is pumped into the equipment and mixed with the sewage. The sewage is aerobically incubated for 1-2 days to make the sludge fully contact with the elastic biological filler. After 1-2 days, it is settled for 0.5 h, the supernatant is discharged, and the sewage is pumped in again, and the continuous influent and effluent are carried out at 10-20% of the designed flow rate; when the biological film adheres to the surface of the filler, the influent flow rate is adjusted to 50% of the designed flow rate, and when the effluent water quality reaches the standard, the influent flow rate is adjusted to the designed flow rate;

[0047] The process operating parameters in Step 1 are as follows: the hydraulic retention time in the anaerobic zones 1-3 and the anoxic zones 1-4 is 3-5 h; the filling rate of the elastic biological fillers 2-2 in the anaerobic zones 1-3, the anoxic zones 1-4, the aerobic zone I 1-5 and the aerobic zone II 1-6 is 60-80%; the hydraulic retention time in the aerobic zone I 1-5 and the aerobic zone II 1-6 is 6-10 h, the biological film loading on the surface of the elastic biological fillers is 3-5 g MLSS / g, the reflux ratio is 100% - 200%, the dissolved oxygen in the anaerobic zone 1-3 is 0-0.2 mg / L, the dissolved oxygen in the anoxic zone 1-4 is 0.2-0.5 mg / L, the dissolved oxygen in the aerobic zone I 1-5 and the aerobic zone II 1-6 is 2-4 mg / L, and the temperature of the water layer around the electric heating wire 2-1 and the elastic biological filler 2-2 is between 9-17 °C.

[0048] Step 2. Stable operation under low temperature conditions: The domestic sewage inlet 1-1 to be treated is pumped into the anaerobic zone 1-3, and then flows into the anoxic zone 1-4, the aerobic zone I 1-5 and the aerobic zone II 1-6 in turn through the baffle, and the sewage is in full contact with the biological film attached to the electric heating wire 2-1 and the membrane module 2-2 to achieve pollutant removal.

[0049] Through the reflux pump 9-2, the nitrified liquid in the aerobic zone II 1-6 is refluxed to the anoxic zone 1-4 through the reflux pipeline 9-1 for nitrate nitrogen removal; the sewage after biological treatment is precipitated in the vertical flow secondary sedimentation tank 1-7 and then discharged from the outlet 1-2, and the generated excess sludge is discharged through the sludge discharge pipe at the bottom of the vertical flow secondary sedimentation tank 1-7. During the operation, the voltage regulating power supply 2-4 and the digital display control box 7 of the electric heating biological membrane module 2 are turned on. After the thermometer 3 converts the temperature data into an electric signal and transmits it to the digital display control box 7, the digital display control box 7 outputs a control signal to the voltage regulating power supply 2-4 according to the built-in mathematical model to adjust the voltage and ensure the heating power of the electric heating wire 2-1. After the electric heating wire 2-1 is started, the water layer around the electric heating wire 2-1 and the elastic biological filler 2-2 is heated to ensure the heat demand of the microorganisms in the pool and improve the microbial activity.

[0050] During the treatment process in Step 2, the hydraulic retention time in the anaerobic zones 1-3 and the anoxic zones 1-4 is 3-5 h; the hydraulic retention time in the aerobic zone I 1-5 and the aerobic zone II 1-6 is controlled to be 6-10 h, the biological film loading on the surface of the elastic biological fillers is 3-5 g MLSS / g, the reflux ratio is 50% - 100%, the dissolved oxygen in the anaerobic zone 1-3 is 0-0.2 mg / L, the dissolved oxygen in the anoxic zone 1-4 is 0.2-0.5 mg / L, and the dissolved oxygen in the aerobic zone I 1-5 and the aerobic zone II 1-6 is 2-4 mg / L; the working voltage of the voltage regulating power supply 2-4 is 6-12 V, and the corresponding heating power is 14.4-57.6 W; the working voltage of the voltage regulating power supply 2-4 will gradually increase with the decrease of the influent water temperature to ensure that the temperature of the water layer around the electric heating wire 2-1 and the elastic biological filler 2-2 is between 9-17 °C.

[0051] Example 1

[0052] The decentralized biofilm low-temperature sewage treatment device based on the Joule heat effect and carrier adsorption in this example consists of a reactor main body 1, an electric heating membrane assembly 2, a thermometer 3, an aeration system 4, a water inlet pipe 5, a drain pipe 6, a digital display control box 7, a heat preservation layer 8, and a reflux adjustment module 9.;

[0053] An inlet 1-1 and an outlet 1-2 are arranged on the left and right sides of the reactor main body 1. A plurality of baffle plates are arranged inside the reactor, dividing the reactor into an anaerobic zone 1-3, an anoxic zone 1-4, an aerobic zone I 1-5, an aerobic zone II 1-6, and a vertical flow secondary sedimentation tank 1-7; a thermometer access port 1-8 is also arranged at the top of the reactor main body 1; the total effective volume of the reactor main body 1 is 37L, and the effective volumes of the anaerobic zone 1-3, the anoxic zone 1-4, the aerobic zone I 1-5, and the aerobic zone II 1-6 are all 7.5L; the effective volume of the vertical flow secondary sedimentation tank is 7L, and the slope i of the bottom mud hopper is 1.75;

[0054] The electric heating biofilm assembly 2 is arranged in the reactor main body 1. An elastic biological filler 2-2 is spirally wound around an electric heating wire 2-1, and is connected in parallel to a voltage regulating power supply 2-4 by a waterproof wire 2-3. The voltage regulating power supply 2-4 is connected to the digital display control box 7, and the output voltage is adjusted within the range of 3-12V through the built-in program of the digital display control box 7; the electric heating wire 2-1 is a multi-strand nickel-chromium wire wrapped with silica gel, Φ = 2.5mm, the length is 0.8m, and the resistance value is 80Ω; the elastic biological filler 2-1 is a snowflake-shaped aldehydeized fiber branch, the unit diameter Φ = 100mm, and the mass density is 3.1kg / m 3 , the wire diameter is 0.35mm, fixed and installed by a steel bracket, the arrangement spacing is 60mm, and the filling rate is 80%. Such an arrangement form not only helps to cut bubbles and obtain a better aeration effect, but also more conforms to the heat field distribution of the electric heating wire heating, improving the heat energy utilization rate;

[0055] The thermometer 3 is arranged in the reactor main body 1 through the thermometer access port 1-7 and is connected to the digital display control box 7 to monitor the inlet water temperature in real time;

[0056] The aeration system 4 consists of a blower 4-1, an aeration pipe 4-2, and a microporous aeration pipe 4-3; the blower 4-1 is connected to the microporous aeration pipe 4-3 through the aeration pipe 4-2; the aeration pipe 4-3 is fixed at the bottom of the reactor main body 1, and the microporous aeration pipe 4-3 is installed in the reactor main body 1 through the aeration pipe 4-2; the microporous aeration pipe 4-3 is installed 30mm away from the bottom of the reactor 1;

[0057] The water inlet pipe 5 is connected to the reactor main body 1 through the water inlet 1-1; the drain pipe 6 is connected to the reactor main body 1 through the water outlet 1-2; the heat insulation layer 8 is a polyurethane heat insulation board with a thickness of 5 cm and a thermal conductivity of 0.02 W / (m·K), which is fixed on the outside of the reactor main body 1 for heat insulation of the reactor main body 1;

[0058] The reflux regulation module 9 includes a reflux pipeline 9-1, one end of which is communicated with the aerobic zone II 1-6, and the other end is communicated with the anoxic zone 1-4; a reflux pump 9-2 is arranged on the reflux pipeline 9-1 for transporting the liquid from one end of the reflux pipeline 9-1 to the other end; a reflux valve 9-3 is used to control the opening and closing of the reflux pipeline 9-1;

[0059] Example 2

[0060] The difference from Example 1 is that the water body temperature is controlled at 8°C, the working voltage of the voltage regulating power supply 2-4 is 6V, and the corresponding heating power is 14.4W.

[0061] Example 3

[0062] The difference from Example 1 is that the water body temperature is controlled at 8°C and the voltage regulating power supply 2-4 is turned off.

[0063] The method for treating low-temperature domestic sewage by using the decentralized biofilm low-temperature sewage treatment device based on the Joule heat effect and carrier adsorption of Examples 1, 2, and 3 is carried out according to the following steps:

[0064] Step 1: Under the condition that the inlet water temperature is 8°C, turn on the voltage regulating power supply 2-4 of the electric heating biofilm component 2 and the digital display control box 7. After the thermometer 3 converts the temperature data into an electric signal and transmits it to the digital display control box 7, the digital display control box 7 outputs a control signal to the voltage regulating power supply 2-4 to adjust the voltage according to the built-in mathematical model to ensure the heating power of the electric heating wire 2-1. After the electric heating wire 2-1 is started, the water layer around the electric heating wire 2-1 and the elastic biological filler 2-2 is heated to ensure the heat demand of the microorganisms in the pool and improve the activity of the microorganisms. The working voltage of the voltage regulating power supply 2-4 reaches the target voltage, and the surface biofilm and the water layer around the elastic biological filler 2-2 are heated through the electric heating wire 2-1.

[0065] Step 2: Pump the inlet 1-1 of the domestic sewage to be treated into the anaerobic zone 1-3, and then flow through the baffle plate and into the anoxic zone 1-4, aerobic zone I 1-5, and aerobic zone II 1-6 in sequence. The sewage is in full contact with the biofilm attached to the electric heating wire 2-1 and the membrane module 2-2 to achieve pollutant removal. Through the reflux pump 9-2, the nitrified liquid in the aerobic zone II 1-6 is refluxed to the anoxic zone 1-4 through the reflux pipeline 9-1 for nitrate nitrogen removal, and the reflux ratio is controlled at 50%-100% during the process. During the treatment process, the hydraulic retention time (HRT) of the anaerobic zone 1-3 and the anoxic zone 1-4 is 3h; the hydraulic retention time (HRT) in the aerobic zone I 1-5 and the aerobic zone II 1-6 is controlled at 6h, the biofilm load on the surface of the elastic biological filler is 3-5g MLSS / g, the reflux ratio is 50%-100%, the dissolved oxygen in the anaerobic zone 1-3 is 0-0.2mg / L, the dissolved oxygen in the anoxic zone 1-4 is 0.2-0.5mg / L, and the dissolved oxygen in the aerobic zone I 1-5 and the aerobic zone II 1-6 is 2-4mg / L.

[0066] Step 3: Operate the reactor stably under the conditions of an influent load of 2m 3 / (m 3 ·d), a retention time (HRT) of 12h, a pH value of 6.5-7.5, and the water layer temperature around the electric heating wire 2-1 and the elastic biological filler 2-2 between 9-17°C. After the treated sewage is precipitated in the vertical flow secondary sedimentation tank 1-7, it is discharged from the outlet 1-2, and the excess sludge generated is discharged through the sludge discharge pipe at the bottom of the vertical flow secondary sedimentation tank 1-7.

[0067] In Example 1, the working voltage of the voltage regulating power supply 2-4 is 9V, and the corresponding heating power is 32.4W. At this time, the surface temperature of the electric heating wire 2-1 is 23°C, and the water layer temperature around the elastic biological filler 2-2 is between 11-23°C; in Example 2, the working voltage of the voltage regulating power supply 2-4 is 6V, and the corresponding heating power is 14.4W. At this time, the surface temperature of the electric heating wire 2-1 is 17°C, and the water layer temperature around the elastic biological filler 2-2 is between 9-17°C; in Example 3, the surface temperature of the electric heating wire 2-1 and the water layer temperature around the elastic biological filler 2-2 are the same as the influent water temperature, which is 8°C; the influent and effluent water quality conditions during the operation of Examples 1, 2, and 3 are plotted in Figure 4 the

[0068] In Examples 1 and 2, since the biofilm is heated by the electrothermal biofilm module 2, it has a higher pollutant removal efficiency, and Example 1 is better than Example 2 in the removal of COD, NH4 + -N, TN, and TP; in Example 3, since the heating is not turned on, the pollutant removal efficiency is significantly lower than that of Examples 1 and 2.

[0069] In the decentralized biofilm low-temperature sewage treatment device based on the Joule heating effect and carrier adsorption in this embodiment, the electric heating wire arranged at the center of the biofilm carrier adopts a low-power and continuous internal heating design, which can improve the heat transfer efficiency and optimize the heat field distribution under lower operating energy consumption. By forming local high-temperature regions on the surface of the electric heating wire, the surface of the packing and the vicinity thereof, global heating is avoided, and while reducing the heating energy consumption, the activity of the biofilm in the high-temperature region is effectively enhanced. Under the low-temperature condition of 8 °C, by setting an appropriate heating power, the removal efficiencies of the device for COD, NH4 + -N, TN and TP can reach 91.53%, 80.96%, 86.06% and 60.13% respectively, and the effluent water quality reaches the first-class A standard in the "Discharge Standard of Pollutants for Municipal Wastewater Treatment Plants" (GB 18918-2002).

[0070] In the present invention, by arranging an electric heating wire at the center of the biofilm carrier for low-power and continuous heating, it has lower operating energy consumption, higher heat transfer efficiency and more uniform temperature distribution. The internal heating mode with the electric heating wire evenly placed inside the pool body can centrally heat the area where the biofilm is located, generate local high temperatures on the surface of the packing and the vicinity thereof, enhance the activity of the microorganisms growing on the surface of the packing and increase the biochemical treatment rate and effect. Global heating of the sewage in the pool body is avoided, and the heating energy consumption is reduced; the heat generated by the electric heating wire is directly transferred to the water layer where the biofilm and the elastic bio-packing are located, avoiding the heat loss generated during the heat transfer process from the pool wall to the inside of the pool; the internal heating mode can form a temperature distribution that gradually decreases from the inside to the outside in the pool body, form different temperature regions around the packing, enable the surface of the packing to enrich microorganisms with different optimal temperatures, increase the species richness in the pool, and enhance the low-temperature operation stability and the ability to resist low-temperature shock loads of the system; the temperature distribution that gradually decreases from the inside to the outside can also reduce the temperature difference between the sewage temperature in the pool body and the external environment temperature, thereby reducing the heat exchange between the pool body and the environment and reducing the heat loss.

[0071] The above are only the preferred embodiments of the present invention, and do not impose any form of limitation on the present invention. Although the present invention has been disclosed above with the preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art, without departing from the scope of the technical solution of the present invention, can make some changes or modifications to the above-disclosed technical content to make equivalent embodiments with equivalent changes. However, as long as it does not depart from the content of the technical solution of the present invention, based on the technical essence of the present invention, any simple modification, equivalent replacement and improvement of the above embodiments within the spirit and principle of the present invention still fall within the protection scope of the technical solution of the present invention.

Claims

1. A decentralized biofilm low-temperature sewage treatment device based on the Joule heating effect and carrier adsorption, characterized in that It mainly includes a reactor main body (1), an electric heating film assembly (2), an aeration system (4) and a reflux regulation module (9); The reactor main body (1) is respectively provided with a water inlet (1-1) and a water outlet (1-2) on its left and right sides. A plurality of baffle plates are arranged inside the reactor main body (1), dividing the reactor main body (1) into an anaerobic zone (1-3), an anoxic zone (1-4), an aerobic zone I (1-5), an aerobic zone II (1-6) and a vertical flow secondary sedimentation tank (1-7); The electric heating biofilm assembly (2) is arranged in the reactor main body (1). An elastic biological filler (2-2) is spirally wound on the electric heating wire (2-1) and is connected in parallel to a voltage regulating power supply (2-4) by a waterproof wire (2-3); The aeration system (4) includes a blower (4-1), an aeration pipeline (4-2), and a microporous aeration pipe (4-3); The blower (4-1) is connected to the microporous aeration pipe (4-3) through the aeration pipeline (4-2); The aeration pipeline (4-3) is fixed to the bottom of the reactor main body (1), and the microporous aeration pipe (4-3) is installed in the reactor main body (1) through the aeration pipeline (4-2); The reflux regulation module (9) includes a reflux pipeline (9-1) with one end communicating with the aerobic zone II (1-6) and the other end communicating with the anoxic zone (1-4); A reflux pump (9-2) is arranged on the reflux pipeline (9-1) for transporting liquid from one end of the reflux pipeline (9-1) to the other end; A reflux valve (9-3) is used to control the opening and closing of the reflux pipeline (9-1).

2. The decentralized biofilm low-temperature sewage treatment device based on the Joule heat effect and carrier adsorption according to claim 1, wherein A thermometer access port (1-8) is provided at the top of the reactor main body 1; A thermometer (3) is arranged in the reactor main body (1) through the thermometer access port (1-8); A digital display control box (7) is connected to the thermometer (3), and the real-time temperature data is monitored through the digital display control box (7).

3. The decentralized biofilm low-temperature sewage treatment device based on the Joule heating effect and carrier adsorption according to claim 1, characterized in that, A heat preservation layer (8) is fixed to the outside of the reactor main body (1); A water inlet pipe (5) is connected to the reactor main body (1) through the water inlet (1-1); A drain pipe (6) is connected to the reactor main body (1) through the water outlet (1-2).

4. The decentralized biofilm low-temperature sewage treatment device based on the Joule heating effect and carrier adsorption according to claim 1, characterized in that, The electric heating wire (2-1) is a multi-strand nickel-chromium wire wrapped with silica gel, Φ = 2.5mm, and the resistance value is 100Ω / m.

5. The decentralized biofilm low-temperature sewage treatment device based on the Joule heat effect and carrier adsorption according to claim 1, characterized in that, The elastic biological filler is snowflake-shaped aldehydeized fiber branches, with a unit diameter Φ = 100 mm and a mass density of 3.1 kg / m 3 , the arrangement spacing is 60 mm, and the filling rate is 60 - 80%.

6. The decentralized biofilm low-temperature sewage treatment device based on the Joule heating effect and carrier adsorption according to claim 4, wherein The heat preservation layer (8) is a polyurethane heat preservation board with a thickness of 5 cm and a thermal conductivity of 0.018 - 0.024 W / (m·K).

7. The decentralized biofilm low-temperature sewage treatment device based on the Joule heating effect and carrier adsorption according to claim 1, wherein, An inspection opening and an exhaust hole are provided at its top. A cover door is provided at the top of the inspection opening, and a one-way valve is provided on the exhaust hole; An overflow pipe is connected to the rear side of the sewage treatment main device; A drain pipe is connected to the bottom rear side of the sewage treatment main device, and the overflow pipe and the drain pipe converge into a main pipe; An inspection port is opened at the bottom front side of the sewage treatment main device, and the inspection port is opened and closed through a valve.

8. A sewage treatment method, which applies the decentralized biofilm low-temperature sewage treatment device based on the Joule heating effect and carrier adsorption according to any one of claims 1 to 7 above, is characterized in that, It includes the following steps: Step 1. Start under low-temperature conditions: Install the electric heating biofilm assembly (2) in the anaerobic zone (1-3), anoxic zone (1-4), aerobic zone I (1-5) and aerobic zone II (1-6). Pump the domestic sewage to be treated through the water inlet (1-1) with an inlet submersible pump and add excess sludge; Turn on the voltage regulating power supply (2-4) and the digital display control box (7) of the electric heating biofilm component (2). After the thermometer (3) converts the temperature data into an electrical signal and transmits it to the digital display control box (7), the digital display control box (7) outputs a control signal to the voltage regulating power supply (2-4) according to the built-in mathematical model to adjust the voltage and ensure the heating power of the electric heating wire (2-1). After the electric heating wire (2-1) starts, heat the water layer around the electric heating wire (2-1) and the elastic biological filler (2-2). The biochemical process is started by the delayed sludge discharge method. The inoculated sludge is pumped into the equipment and mixed with the sewage. Aerate it for 1-2 days to make the sludge fully contact with the elastic biological filler. After 1-2 days, precipitate for 0.5 h, discharge the supernatant, pump in the sewage again, and continuously inflow and outflow at 10-20% of the designed flow rate. When the biological film adheres to the surface of the filler, adjust the influent flow rate to 50% of the designed flow rate. When the effluent quality reaches the standard, adjust the influent flow rate to the designed flow rate. Step 2: Stable operation under low-temperature conditions: The influent port (1-1) of the domestic sewage to be treated is pumped into the anaerobic zone (1-3), and then flows through the baffle plate and into the anoxic zone (1-4), aerobic zone I (1-5) and aerobic zone II (1-6) in turn. The sewage fully contacts the biological film attached to the electric heating wire (2-1) and the membrane component (2-2) to achieve pollutant removal. Through the reflux pump (9-2), the nitrified liquid in the aerobic zone II (1-6) is refluxed to the anoxic zone (1-4) through the reflux pipeline (9-1) for nitrate nitrogen removal. After the sewage treated biologically is precipitated in the vertical flow secondary sedimentation tank (1-7), it is discharged from the outlet (1-2). The generated excess sludge is discharged through the sludge discharge pipe at the bottom of the vertical flow secondary sedimentation tank (1-7). During the operation, turn on the voltage regulating power supply (2-4) and the digital display control box (7) of the electric heating biofilm component (2). After the thermometer (3) converts the temperature data into an electrical signal and transmits it to the digital display control box (7), the digital display control box (7) outputs a control signal to the voltage regulating power supply (2-4) according to the built-in mathematical model to adjust the voltage and ensure the heating power of the electric heating wire (2-1). After the electric heating wire (2-1) starts, by heating the water layer around the electric heating wire (2-1) and the elastic biological filler (2-2), ensure the heat demand of the microorganisms in the pool and improve the activity of the microorganisms.

9. A sewage treatment method according to claim 8, characterized in that, The process operating parameters in Step 1 are as follows: the hydraulic retention time in the anaerobic zone (1-3) and the anoxic zone (1-4) is 3-5 h; the filling rate of the elastic biological filler (2-2) in the anaerobic zone (1-3), the anoxic zone (1-4), the aerobic zone I (1-5) and the aerobic zone II (1-6) is 60-80%; the hydraulic retention time in the aerobic zone I (1-5) and the aerobic zone II (1-6) is 6-10 h, the biofilm load on the surface of the elastic biological filler is 3-5 g MLSS / g, the reflux ratio is 100% - 200%, the dissolved oxygen in the anaerobic zone (1-3) is 0-0.2 mg / L, the dissolved oxygen in the anoxic zone (1-4) is 0.2-0.5 mg / L, the dissolved oxygen in the aerobic zone I (1-5) and the aerobic zone II (1-6) is 2-4 mg / L, and the temperature of the water layer around the electric heating wire (2-1) and the elastic biological filler (2-2) is between 9-17 °C.

10. A sewage treatment method according to claim 8, characterized in that, In the process of Step 2, the hydraulic retention time in the anaerobic zone (1-3) and the anoxic zone (1-4) is 3-5 h; the hydraulic retention time in the aerobic zone I (1-5) and the aerobic zone II (1-6) is controlled to be 6-10 h, the biofilm load on the surface of the elastic biological filler is 3-5 g MLSS / g, the reflux ratio is 50% - 100%, the dissolved oxygen in the anaerobic zone (1-3) is 0-0.2 mg / L, the dissolved oxygen in the anoxic zone (1-4) is 0.2-0.5 mg / L, the dissolved oxygen in the aerobic zone I (1-5) and the aerobic zone II (1-6) is 2-4 mg / L; the working voltage of the voltage regulating power supply (2-4) is 6-12 V, and the corresponding heating power is 14.4-57.6 W; the working voltage of the voltage regulating power supply (2-4) will gradually increase with the decrease of the influent water temperature to ensure that the temperature of the water layer around the electric heating wire (2-1) and the elastic biological filler (2-2) is between 9-17 °C.

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