A sewage treatment system and method

Abstract

The present invention discloses a sewage treatment system and method. The method includes an anaerobic tank, an anoxic tank and an aerobic tank. The water storage capacity of the anaerobic tank is adjustable, and a direct current electric heater and an alternating current electric heater are provided inside. It also includes a photovoltaic module, a mains power device and a controller. The photovoltaic module directly supplies direct current to the direct current electric heater, and the mains power device supplies alternating current to the alternating current electric heater. The power control module of the controller is used to maintain the total power of the direct current electric heater and the alternating current electric heater within a set total power range when the power of the direct current electric heater is less than the set power value; the water storage capacity control module is used to control the alternating current electric heater to stop working and control the increase of the water storage capacity in the anaerobic tank when the power of the direct current electric heater is not less than the set power value. The electric energy converted from solar energy is directly connected to the load, reducing the investment in inverter and energy storage equipment, and cleverly avoiding the adverse factors of discontinuous electric energy and unstable power when directly using solar energy.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and in particular to a sewage treatment system and method. Background Art

[0002] AAO (Anaerobic-Anoxic-Oxic) is also called A2O. It is a commonly used sewage treatment process. It combines the traditional activated sludge and biological nitrification processes, taking advantage of each other's strengths to more effectively remove organic matter from the water, and has good nitrogen and phosphorus removal effects. The specific process is: sewage flows into the anaerobic tank to release phosphorus, and some organic matter is ammonified; then it flows into the facultative aerobic tank for nitrogen removal, and nitrate nitrogen is sent from the aerobic tank through internal circulation; then sewage flows into the aerobic tank, where organic matter removal, nitrification and phosphorus absorption are all carried out; finally, it flows into the sedimentation tank for mud and water separation, part of the sludge flows back to the anaerobic tank, and the supernatant is discharged as treated water.

[0003] In the whole sewage treatment process, the temperature of sewage is the most critical factor affecting the sewage treatment effect. If the temperature of sewage is too high or too low, it will have a direct impact on the treatment of activated sludge sewage. For example, when the environmental microorganisms are below 5°C, the denitrification enzymatic reaction significantly decreases or even stops, and the optimal temperature is 30-60°C; it is generally believed that when it is below 12°C, the denitrification denitrification reaction rate decreases significantly. In addition, in general sewage treatment operation practice, the optimal growth temperature of nitrifying bacteria in activated sludge is 25-35°C. When the temperature is below 18°C, the growth rate of nitrifying bacteria is halved, and when it is below 10°C, the enzymatic reaction of nitrifying bacteria stops significantly. In short, keeping the water in the sewage treatment process at a suitable temperature will greatly improve the sewage treatment efficiency, but due to the huge total amount of sewage, heating will undoubtedly consume more heat. With the popularization of new energy technologies such as solar energy and wind energy, sewage treatment plants occupy a larger area and can be combined with solar power generation. However, since the electric energy converted by solar panels is discontinuous and the power is unstable, and the current fluctuates with the light intensity, most of them are used after battery storage, inverter conversion and other operations, which results in a lot of energy loss and requires more inverter and energy storage equipment. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a sewage treatment system and method, which directly connects the electric energy converted from solar energy to the load, heats the sewage, increases the sewage treatment temperature, reduces the investment in inverter and energy storage equipment, and reduces the energy consumption cost during sewage treatment.

[0005] To solve the above technical problems, a sewage treatment system of the present invention includes an anaerobic tank, an anoxic tank, and an aerobic tank that are connected in sequence. The water storage capacity of the anaerobic tank can be adjusted, and a direct current electric heater and an alternating current electric heater are provided inside. It also includes a photovoltaic module, a mains power device, and a controller. The photovoltaic module is used to convert solar energy into electrical energy and directly supply direct current to the direct current electric heater. The mains power device is used to supply industrial frequency alternating current to the alternating current electric heater. The controller includes a power control module and a water storage capacity control module. The power control module is used to control and adjust the power of the alternating current electric heater when the power of the direct current electric heater is less than the set power value, so that the total power of the direct current electric heater and the alternating current electric heater is maintained within the set total power range. The water storage capacity control module is used to control the alternating current electric heater to stop working when the power of the direct current electric heater is not less than the set power value, and control to increase the water storage capacity in the anaerobic tank to reduce the water temperature rise rate in the anaerobic tank, so that the water temperature in the anaerobic tank is maintained within the set temperature range.

[0006] Preferably, the set power value takes the upper limit value of the set total power range. When the total power of the direct current electric heater and the alternating current electric heater is maintained within the set total power range and the water storage capacity of the anaerobic tank is at the initial value, the water temperature in the anaerobic tank will be maintained within the set temperature range, and the set temperature range can be: 30-45°C.

[0007] In the above sewage treatment system, through the photovoltaic module for photoelectric conversion, the generated electrical energy is directly supplied to the direct current electric heater without first being stored in a storage battery or undergoing an inversion conversion, reducing energy loss and also saving the investment in energy storage and inversion equipment. In addition, since the output power of the photovoltaic module fluctuates with the light intensity, when there is no light, that is, when the output power is zero, only the mains power is used for heating to maintain the sewage temperature; when the light is weak and the output power is insufficient, the photovoltaic module and the mains power are jointly used for heating to maintain the sewage temperature; when the light is strong and the output power is too large, only the photovoltaic module is used for heating, and by increasing the water storage capacity of the anaerobic tank, the adverse factors of discontinuous electrical energy and unstable power when directly using solar energy are cleverly avoided. The solar energy is organically structured with sewage treatment, ensuring sewage treatment efficiency while saving energy and reducing emissions, and also reducing the energy cost.

[0008] Preferably, when controlling to increase the water storage capacity in the anaerobic tank, the water inlet rate of the anaerobic tank remains unchanged.

[0009] As an improvement to the sewage treatment system of the present invention, the water storage control module is further configured to, after controlling to increase the water storage volume in the anaerobic tank, when the power of the DC electric heater is less than the set power value, control to reduce the water storage volume in the anaerobic tank to the initial value. During a day, the distribution diagram of the light intensity over time generally shows a peak shape. After increasing the water storage volume of the anaerobic tank, there will surely be a light intensity at which the power of the DC electric heater is less than the set power value. At this time, the power control module will keep the DC electric heater and the AC electric heater within the set total power range, and can restore the water storage volume in the anaerobic tank to the initial value. On the one hand, it is for use tomorrow, and on the other hand, it avoids the situation that when heating with the set total power, the total water storage volume is too large to maintain the normal water temperature.

[0010] As another improvement to the sewage treatment system of the present invention, the system further includes a light intensity forecasting device, and the light intensity forecasting device is used to forecast the relationship between the light intensity and time every day; the controller further includes a preset module, and the preset module is used to set the increase value of the water storage volume of the anaerobic tank controlled and adjusted on the same day according to the forecast relationship between the light intensity and time every day.

[0011] Through the predicted light intensity situation of the day, calculate in advance the increase value of the water storage volume of the anaerobic tank when it needs to be controlled and adjusted on the same day, so as to carry out scientific and accurate regulation, and keep the temperature of the anaerobic tank within the set temperature range, without being affected by the fluctuation of the light intensity.

[0012] Furthermore, a temperature alarm device is provided inside the anaerobic tank, and the temperature alarm device is used to give an alarm when the temperature of the anaerobic tank reaches the maximum temperature value. Monitor the temperature inside the anaerobic tank, discover abnormal situations in time, and further ensure that the water temperature of the anaerobic tank is within the set temperature range when the light intensity fluctuates.

[0013] As yet another improvement to the sewage treatment system of the present invention, the water storage volumes of the anoxic tank and the aerobic tank can both be adjusted, and the anoxic tank, the anaerobic tank, and the aerobic tank all adjust the water storage volume by adjusting the water storage capacity. When the water storage control module controls and adjusts the change in the water storage volume in the anaerobic tank, it simultaneously adjusts the water storage volume of the anoxic tank and / or the aerobic tank, so that the total water storage volume of the anoxic tank, the anaerobic tank, and the aerobic tank remains unchanged, and further keeps the water outlet rate of the aerobic tank within the set speed range.

[0014] Since the anaerobic tank, the anoxic tank, and the aerobic tank are interconnected, when adjusting the water storage volume of the anaerobic tank, coordinating the adjustment of the water storage volumes of the anoxic tank and the aerobic tank can keep the total water storage volume of the three tanks unchanged. If the influent rate remains stable, the water outlet rate can remain basically unchanged during the adjustment process, and the impact on the water outlet rate of the entire sewage treatment is relatively small.

[0015] Furthermore, when controlling to reduce the water storage amount in the anaerobic tank, the water storage volume of the anaerobic tank is gradually reduced, so that the sewage effluent rate in the anaerobic tank becomes larger and flows to the anaerobic tank faster; the water storage amount of the anaerobic tank and / or the aerobic tank is synchronously adjusted to increase, and the water storage volume of the corresponding tank is gradually increased. The total water storage amount of the three tanks remains unchanged, and the effluent rate of the aerobic tank is maintained within the set speed range.

[0016] Furthermore, when controlling to increase the water storage amount in the anaerobic tank, the water storage capacity of the anaerobic tank is increased to reduce the water outlet rate of the anaerobic tank; at the same time, the water storage capacity of the anaerobic tank and / or the aerobic tank is reduced, and the water storage capacity of the corresponding tank is gradually reduced. The total water storage capacity of the three tanks remains unchanged, so that the water outlet rate of the aerobic tank is maintained within the set speed range.

[0017] As another improvement of the sewage treatment system of the present invention, the system also includes a tank body, and the internal interval of the tank body is provided with a first adjustable partition and a second adjustable partition, the first adjustable partition and the second adjustable partition divide the tank body into the facultative anoxic tank, the anaerobic tank and the aerobic tank in sequence, and the first adjustable partition and the second adjustable partition are controlled and adjusted by the controller to realize the water storage volume adjustment of the anaerobic tank.

[0018] By adjusting the first adjustable baffle, the water storage capacity and water storage amount of the anaerobic tank and the facultative aerobic tank can be linked and adjusted; by adjusting the second adjustable baffle, the water storage capacity and water storage amount of the anaerobic tank and the aerobic tank can be linked and adjusted. The tank body structure is cleverly designed.

[0019] Furthermore, when controlling and adjusting the water storage capacity in the anaerobic tank, the order of adjusting the water storage capacity of the anaerobic tank and the aerobic tank is determined according to the carbon-nitrogen ratio of the actual sewage. When increasing the water storage capacity of the anaerobic tank, if the carbon-nitrogen ratio is greater than the first set value and the organic matter content is high, the water storage capacity of the anaerobic tank is preferentially controlled to be reduced; if the carbon-nitrogen ratio is not greater than the first set value and the total nitrogen content of the sewage is high, the water storage capacity of the aerobic tank is preferentially controlled to be reduced.

[0020] As another improvement of the sewage treatment system of the present invention, the system also includes a sedimentation reflow tank, a filtration tank and a middle water tank which are sequentially connected to the outlet of the aerobic tank, and the outlet of the middle water tank is provided with a waste heat recovery device.

[0021] Furthermore, a gas lift reflux device is provided on the top of the sedimentation reflux tank, a stirring and flushing device is provided inside the filtration tank, and an electrolyzer is provided inside the intermediate water tank.

[0022] In order to solve the above technical problems, the present invention provides a sewage treatment method based on the above sewage treatment system, comprising the following steps:

[0023] The sewage to be treated flows through the anaerobic tank, the anoxic tank and the aerobic tank in sequence, and in the anaerobic tank, a DC electric heater and an AC electric heater are used in cooperation to heat the sewage. Among them, the DC electric heater is directly supplied with direct current by a photovoltaic module, and the AC electric heater is supplied with alternating current by a mains device. The heating process is as follows:

[0024] When the power of the DC electric heater is less than the set power value, control and adjust the power of the AC electric heater so that the total power of the DC electric heater and the AC electric heater is maintained within the set total power range for joint heating;

[0025] When the power of the DC electric heater exceeds the set power value, control the AC electric heater to stop working, and the DC electric heater heats alone, and control to increase the water storage volume in the anaerobic tank to reduce the water temperature rise rate in the anaerobic tank so that the water temperature in the anaerobic tank is maintained within the set temperature range.

[0026] Preferably, the set power value takes the upper limit value of the set total power range. When the total power of the DC electric heater and the AC electric heater is maintained within the set total power range and the water storage volume in the anaerobic tank is at the initial value, the water temperature in the anaerobic tank will be maintained within the set temperature range, and the set temperature range can be: 30 - 45 °C.

[0027] In the above sewage treatment method, through photovoltaic conversion by the photovoltaic module, the generated electric energy is directly supplied to the DC electric heater without first being stored in a storage battery or undergoing an inversion conversion, reducing energy loss and also saving the investment in energy storage and inversion equipment. In addition, since the output power of the photovoltaic module fluctuates with the light intensity, when there is no light, that is, when the output power is zero, only the mains power is used for heating to maintain the sewage temperature; when the light is weak and the output power is insufficient, the photovoltaic module and the mains power are jointly supplied for heating to maintain the sewage temperature; when the light is strong and the output power is too large, only the photovoltaic module is used for heating, and by increasing the water storage volume in the anaerobic tank, it is possible to avoid the water temperature rising too fast and too high, store the surplus heat, thus skillfully avoiding the adverse situation of discontinuous electric energy and unstable power generated by directly using the photovoltaic module, organically integrating solar energy with sewage treatment, ensuring the sewage treatment efficiency while saving energy and protecting the environment, and also reducing the energy cost.

[0028] Further, after controlling to increase the water storage volume in the anaerobic tank, when the power of the DC electric heater is less than the set power value, control to reduce the water storage volume in the anaerobic tank to the initial value. During a day, the distribution diagram of the light intensity over time generally shows a shape with a single peak. After increasing the water storage volume of the anaerobic tank, there will surely be a light intensity at which the power of the DC electric heater is less than the set power value. At this time, the water storage volume in the anaerobic tank can be restored to the initial value. On the one hand, it is for use tomorrow, and on the other hand, it can avoid the situation that when heating with the set total power, it is not sufficient to maintain the normal water temperature due to the relatively large total water storage volume. At the same time, the stored surplus energy is released, enabling the aerobic tank to have an energy storage function and reducing the investment in energy storage equipment.

[0029] Further, the value for controlling to increase the water storage volume in the anaerobic tank is obtained according to the relationship between the predicted light intensity and time on the current day. Set a scientifically accurate and appropriate value for increasing the water demand to eliminate the influence of the current generated by the photovoltaic module fluctuating with the light intensity.

[0030] Further, when controlling and adjusting the change in the water storage volume in the anaerobic tank, simultaneously adjust the water storage volume of the anoxic tank and / or the aerobic tank so that the total water storage volume of the anoxic tank, the anaerobic tank, and the aerobic tank remains unchanged, thereby keeping the water outlet speed of the aerobic tank within the set speed range and reducing the impact on the water outlet rate.

[0031] In summary, by adopting this sewage treatment system and method, the electric energy generated by the photovoltaic module is directly utilized without first storing it in a storage battery or performing an inversion conversion, reducing energy loss and also saving the investment in energy storage and inversion equipment. In addition, it cleverly avoids the adverse situations of the discontinuous and unstable power of the electric energy directly generated by the photovoltaic module, organically combines solar energy with sewage treatment, ensures the sewage treatment efficiency, is energy-saving and environmentally friendly, and also reduces the energy cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In the drawings:

[0033] Figure 1 is the structural diagram of the sewage treatment system of the present invention.

[0034] Figure 2 is the structural diagram of the first adjustable partition of the sewage treatment system of the present invention.

[0035] Figure 3 is the sectional structural diagram of the first adjustable partition when the water storage volume of the anaerobic tank of the sewage treatment system of the present invention is at the initial value.

[0036] Figure 4 is the sectional structural diagram of the first adjustable partition when the water storage volume of the anaerobic tank of the sewage treatment system of the present invention increases.

[0037] Figure 5This is the overall structure diagram of the sewage treatment system of the present invention.

[0038] In the figure, 1 is the pool body; 100 is the intermediate tank for surplus sludge; 101 is the anoxic tank; 102 is the anaerobic tank; 103 is the aerobic tank; 104 is the sedimentation and reflux tank; 105 is the filtration tank; 106 is the intermediate water tank; 2 is the direct current electric heater; 3 is the alternating current electric heater; 4 is the photovoltaic module; 5 is the mains device; 6 is the controller; 61 is the power control module; 62 is the water storage capacity control module; 63 is the preset module; 7 is the first adjustable partition; 71 is the upper telescopic rotating plate; 711 is the upper U-shaped plate; 712 is the lower U-shaped plate; 713 is the middle sliding plate; 72 is the middle rotating plate; 73 is the bottom support plate; 74 is the telescopic component; 75 is the hinge seat ear; 76 is the first rotating shaft; 77 is the second rotating shaft; 78 is the third rotating shaft; 8 is the second adjustable partition; 9 is the light intensity forecasting device; 10 is the temperature alarm device; 11 is the air-lift reflux equipment; 12 is the stirring and flushing equipment; 13 is the electrolyzer; 14 is the first inclined tube; 15 is the surplus sludge hopper; 16 is the effluent weir; 17 is the blower; 18 is the water pump; 19 is the connecting pipe; 20 is the aeration system; 21 is the first valve; 22 is the second valve; 23 is the third valve; 24 is the backwashing water pump; 25 is the check valve; 26 is the installation valve. Detailed implementation manners

[0039] The following further describes the detailed implementation manners of the present invention with reference to the accompanying drawings. It should be noted here that the description of these implementation manners is for helping to understand the present invention, but does not limit the present invention.

[0040] Figures 1-5 Shows a sewage treatment system of the present invention. As Figure 1 shown, the sewage treatment system includes an anaerobic tank 102, an anoxic tank 101 and an aerobic tank 103 that are connected in sequence. The water storage capacity of the anaerobic tank 102 can be adjusted, and a direct current electric heater 2 and an alternating current electric heater 3 are arranged inside. It also includes a photovoltaic module 4, a mains device 5 and a controller 6. The photovoltaic module 4 is used to convert solar energy into electric energy and directly supply direct current to the direct current electric heater 2. The mains device 5 is used to supply industrial frequency alternating current to the alternating current electric heater 3. The controller 6 includes a power control module 61 and a water storage capacity control module 62. The power control module 61 is used to control and adjust the power of the alternating current electric heater 3 when the power of the direct current electric heater 2 is less than the set power value, so that the total power of the direct current electric heater 2 and the alternating current electric heater 3 is maintained within the set total power range. The water storage capacity control module 62 is used to control the alternating current electric heater 3 to stop working when the power of the direct current electric heater 2 is not less than the set power value, and control to increase the water storage capacity in the anaerobic tank 102 to reduce the water temperature rise rate in the anaerobic tank 102, so that the water temperature in the anaerobic tank 102 is maintained within the set temperature range.

[0041] The photovoltaic module 4 is arranged outside the pond. Generally, there is sufficient space in the sewage treatment plant to install solar panels. A voltage regulator can be connected to the output end of the photovoltaic module 4. The controller 6 is electrically connected to the photovoltaic module 4 and the mains device 5 to achieve power monitoring and control; the controller 6 is also electrically connected to the water storage amount regulating device of the anaerobic pond 102 for control. The water storage amount regulating device of the present invention will be described later. Among them, the set power value takes the upper limit value of the set total power range. When the total power of the DC electric heater 2 and the AC electric heater 3 is maintained within the set total power range and the water storage amount in the anaerobic pond 102 is at the initial value, the water temperature in the anaerobic pond 102 will be maintained within the set temperature range, and the set temperature range can be: 30 - 45 °C. The water inlet rate of the anaerobic pond 102 remains unchanged.

[0042] Optionally, the water storage amount control module 62 is further configured to, after controlling to increase the water storage amount in the anaerobic pond 102, when the power of the DC electric heater 2 is less than the set power value, control to reduce the water storage amount in the anaerobic pond 102 to the initial value.

[0043] During a day, the distribution diagram of the light intensity over time is roughly in a peak shape. After increasing the water storage amount in the anaerobic pond 102, there will surely be a light intensity at which the power of the DC electric heater 2 is less than the set power value. At this time, the power control module 61 will keep the DC electric heater 2 and the AC electric heater 3 within the set total power range, and the water storage amount in the anaerobic pond 102 can be restored to the initial value. On the one hand, it is for use tomorrow, and on the other hand, it avoids the situation that when heating with the set total power, the water temperature cannot be maintained normal due to the relatively large total water storage amount.

[0044] Optionally, the system further includes a light intensity forecasting device 9. The light intensity forecasting device 9 is used to forecast the relationship between the light intensity and time every day; the controller 6 further includes a preset module 63. The preset module 63 is used to set the increase value of the water storage amount of the anaerobic pond 102 controlled and adjusted on the current day according to the forecast relationship between the light intensity and time every day. By predicting the light intensity situation on the current day, the increase value of the water storage amount of the anaerobic pond 102 that needs to be controlled and adjusted on the current day is calculated in advance, so as to perform scientific and accurate regulation, and make the temperature in the anaerobic pond 102 within the set temperature range, without being affected by the light intensity fluctuation.

[0045] The specific calculation steps of the preset module 63 include:

[0046] ① According to the forecast relationship between the light intensity and time every day, obtain the relationship between the output power of the photovoltaic module 4, that is, the power of the DC electric heater 2, and time;

[0047] ② According to the relationship between the power of the DC electric heater 2 and time, calculate the total heat generation amount during the time interval when the power of the DC electric heater 2 exceeds the set power value;

[0048] ③ Calculated based on the total calorific value, the total amount of water that can raise the sewage temperature to the lower limit of the set temperature range;

[0049] ④ Calculate the increase in water storage capacity of anaerobic tank 102 based on the total water volume; the total water volume minus the initial value is the desired value.

[0050] Optionally, a temperature alarm device 10 is provided inside the anaerobic tank 102, and the temperature alarm device 10 is used to alarm when the temperature of the anaerobic tank 102 reaches the maximum temperature value. The temperature alarm device 10 is connected to a temperature detector provided in the anaerobic tank 102 to monitor the temperature in the anaerobic tank 102, and detect abnormal conditions in time, and further ensure that the water temperature of the anaerobic tank 102 is within the set temperature range when the light intensity fluctuates. Of course, temperature detectors can also be provided in the facultative aerobic tank 101 and the aerobic tank 103 to monitor the temperature.

[0051] Optionally, the water storage capacity of the anaerobic tank 101 and the aerobic tank 103 can be adjusted, and the anaerobic tank 101, the anaerobic tank 102 and the aerobic tank 103 all achieve water storage capacity adjustment by adjusting the water storage volume. When the water storage capacity control module 62 controls and adjusts the change of the water storage capacity in the anaerobic tank 102, it also adjusts the water storage capacity of the anaerobic tank 101 and / or the aerobic tank 103, so that the total water storage capacity of the anaerobic tank 101, the anaerobic tank 102 and the aerobic tank 103 remains unchanged, thereby keeping the water outlet rate of the aerobic tank 103 within a set speed range.

[0052] Since the anaerobic tank 102, the facultative anoxic tank 101 and the aerobic tank 103 are interconnected, when adjusting the water storage capacity of the anaerobic tank 102, the water storage capacity of the facultative anoxic tank 101 and the aerobic tank 103 can be coordinated to keep the total water storage capacity of the three tanks unchanged. If the water inlet rate remains stable, the water outlet rate can be kept basically unchanged during the adjustment process, which has little impact on the water outlet rate of the entire sewage treatment.

[0053] Optionally, the system further comprises a tank body 1, wherein the internal interval of the tank body 1 is provided with a first adjustable partition 7 and a second adjustable partition 8, wherein the first adjustable partition 7 and the second adjustable partition 8 sequentially divide the tank body 1 into an anaerobic tank 101, an anaerobic tank 102 and an aerobic tank 103, and the first adjustable partition 7 and the second adjustable partition 8 are controlled and adjusted by a controller 6 to adjust the water storage volume of the anaerobic tank 102. By adjusting the first adjustable partition 7, the water storage volume and water storage amount of the anaerobic tank 102 and the anaerobic tank 101 can be adjusted in linkage; by adjusting the second adjustable partition 8, the water storage volume and water storage amount of the anaerobic tank 102 and the aerobic tank 103 can be adjusted in linkage, and the structure design of the tank body 1 is ingenious.

[0054] like Figures 2-4As shown, the first adjustable partition 7 includes an upper telescopic rotating plate 71, a middle rotating plate 72 and a bottom support plate 73, and the three plates are all rectangular blocks. The bottom support plate 73 is fixed to the bottom surface of the pool body 1; the bottom edge of the middle rotating plate 72 is rotatably set on the top edge of the bottom support plate 73, the top edge of the middle rotating plate 72 is rotatably connected to the bottom edge of the upper telescopic rotating plate 71, and the top edge of the upper telescopic rotating plate 71 is rotatably set on the first rotating shaft 76, and the two ends of the first rotating shaft 76 are rotatably set on the pool body 1.

[0055] The outer surface of the upper telescopic rotating plate 71 is provided with a telescopic assembly 74, which can be an oil cylinder or an air cylinder; the outer surface of the middle rotating plate 72 is provided with an articulated seat ear 75 hinged to the output end of the telescopic assembly 74, and the articulated axis of the articulated seat ear 75 and the output end of the telescopic assembly 74 is located at the outer top of the middle rotating plate 72. Optionally, the articulated seat ear 75 has a C-shaped support arm, and the hinge point is located at the top of the C-shaped arm; there are two telescopic assemblies 74, and the tail end is hinged on the first rotating shaft 76.

[0056] Driven by the telescopic assembly 74, the middle rotating plate 72 rotates away from the anaerobic tank 102, and the upper telescopic rotating plate 71 also rotates and extends, expanding the side wall of the anaerobic tank 102 toward the anoxic tank 101, so that the water storage capacity of the anaerobic tank 102 becomes larger, and the water storage volume becomes larger. At the same time, the linkage adjustment makes the water storage capacity of the anoxic tank 101 smaller, and the water storage volume becomes smaller, but the water storage volume of the two remains basically unchanged. Compared with the commonly used method of adjusting the tank capacity by moving the plug plate, the first adjustable partition plate 7 structure of the present invention has small resistance during adjustment, and the adjustment process is gentle. It can be adjusted during the sewage treatment process and has a wide range of applications.

[0057] The upper telescopic rotating plate 71 includes an upper U-shaped plate 711, a lower U-shaped plate 712 and a middle sliding plate 713. The U-shaped openings of the upper U-shaped plate 711 and the lower U-shaped plate 712 are arranged opposite to each other; the top of the middle sliding plate 713 extends into the U-shaped opening of the upper U-shaped plate 711, and the bottom of the middle sliding plate 713 extends into the U-shaped opening of the lower U-shaped plate 712, and can slide in translation in the U-shaped opening. Optionally, a sliding guide rail is arranged between the middle sliding plate 713 and the upper U-shaped plate 711 and the lower U-shaped plate 712 for guidance.

[0058] The top edge of the upper U-shaped plate 711 is provided with a first rotating shaft 76, and both ends of the first rotating shaft 76 are rotatably provided on the pool body 1. A second rotating shaft 77 is provided between the lower U-shaped plate 712 and the top edge of the middle rotating plate 72, and both ends of the second rotating shaft 77 are not fixed. A third rotating shaft 78 is provided between the bottom edge of the middle rotating plate 72 and the top edge of the bottom supporting plate 73, and both ends of the third rotating shaft 78 are fixed.

[0059] In addition, a sliding seal structure, such as a sealing lip, is provided between the upper telescopic rotary plate 71 and the middle rotary plate 72 and the inner wall of the pool body 1.

[0060] The first adjustable partition 7 and the second adjustable partition 8 have the same structure and are arranged oppositely. The first adjustable partition 7 is arranged between the anaerobic pool 102 and the facultative anaerobic pool 101, and its height is less than that of the second adjustable partition 8. The water in the anaerobic pool 102 overflows and flows into the facultative anaerobic pool 101.

[0061] Of course, the first adjustable partition 7 can also be a vertical plate, and the whole can move in the pool body 1 for adjustment.

[0062] Optionally, when controlling and adjusting the water storage volume in the anaerobic pool 102, the sequence of adjusting the water storage volumes of the facultative anaerobic pool 101 and the aerobic pool 103 is determined according to the actual carbon-nitrogen ratio of the sewage. The main function of the facultative anaerobic pool 101 is nitrogen removal, and the decomposition of organic matter can be completed in the aerobic pool 103. When increasing the water storage volume of the anaerobic pool 102, if the carbon-nitrogen ratio is greater than the first set value and the organic matter content is relatively high, the water storage volume of the facultative anaerobic pool 101 is preferentially controlled to be reduced; if the carbon-nitrogen ratio is not greater than the first set value and the total nitrogen content of the sewage is relatively high, the water storage volume of the aerobic pool 103 is preferentially controlled to be reduced.

[0063] As Figure 5 shown, the system further includes a sedimentation and reflux pool 104, a filtration pool 105, and a middle water pool 106 that are sequentially connected to the water outlet of the aerobic pool 103. A waste heat recovery device is provided at the water outlet of the middle water pool 106. Since the water temperature remains at a relatively high level during the entire sewage treatment process, the discharged water can be subjected to waste heat recovery. The recovered heat can be used to heat the water in the front-end anaerobic pool 102, facultative anaerobic pool 101, etc., and can also be used elsewhere, further saving energy.

[0064] Optionally, the system further includes a surplus sludge intermediate pool 100 provided at the front end of the pool body 1. An air-lift reflux device 11 is provided at the top of the sedimentation and reflux pool 104, a stirring and flushing device 12 is provided inside the filtration pool 105, and an electrolyzer 13 is provided inside the middle water pool 106.

[0065] A first inclined tube 14 is installed at the upper part of the surplus sludge intermediate pool 100, a surplus sludge hopper 15 is provided at the lower part, and a sludge discharge perforated pipe is arranged in the sludge hopper; there is an outlet trough at the upper part of the surplus sludge intermediate pool 100, a horizontal outlet weir 16 is provided, and it is communicated with the anaerobic pool 102; the surplus sludge intermediate pool 100 pumps the raw water into it through a water pump 18.

[0066] The anaerobic tank 102 is arranged between the anoxic tank 101 and the aerobic tank 103; the anaerobic tank 102 is composed of the area between the first adjustable partition board 7 and the second adjustable partition board 8; the anaerobic tank 102 is provided with a direct-current electric heater 2 and an alternating-current electric heater 3; the photovoltaic module 4 directly supplies direct current to the direct-current electric heater 2 through an electric control device, a direct-current heating controller, etc.; the top of the first adjustable partition board 7 of the anaerobic tank 102 is provided with a water passing hole or directly overflows from the bottom into the anoxic tank 101.

[0067] The bottom of the anoxic tank 101 is connected to the aerobic tank 103 through a connecting pipe 19; the upper part of the anoxic tank 101 is connected to the sedimentation and reflux tank 104 through an air-lift reflux device 11 and its pipeline.

[0068] An aeration system 20 is arranged at the bottom of the aerobic tank 103 and is connected to a blower 17; the water inlet pipe at the bottom of the aerobic tank 103 is connected to the anoxic tank 101; the drainage hole in the middle of the aerobic tank 103 is connected to the sedimentation and reflux tank 104; a sludge concentration meter, a temperature detector, a dissolved oxygen meter, etc. are arranged in the aerobic tank 103.

[0069] The sedimentation and reflux tank 104 is arranged on the inclined side wall of the aerobic tank 103. The sludge and intermediate water in the aerobic tank 103 flow back to the aeration and stirring area at the bottom of the aerobic tank 103 through the bottom channel of the sedimentation and reflux tank 104. The bottom of the sedimentation and reflux tank 104 is a funnel-shaped reflux trough, and an inclined tube layer is arranged in the middle; a nitrification liquid reflux air-lift pipeline and an air-lift reflux device 11 are arranged at the upper part of the sedimentation and reflux tank 104; an effluent overflow trough opening is arranged at the upper part of the sedimentation and reflux tank 104 and is connected to the water distribution trough of the inlet of the filtration tank 105.

[0070] The filtration tank 105 and the intermediate water tank 106 are of an upper and lower structure. The upper filtration tank 105 is communicated with the intermediate water tank 106 at the bottom. A four-way pipeline is arranged at the bottom, and the discharge sequence is controlled by a valve. The first valve 21 connects the filtration tank 105 and the intermediate water tank 106. The second valve 22 connects the emptying and sludge discharge pipeline. The third valve 23 connects the backwashing water pump 24. A check valve 25 is connected in the middle. The backwashing water pump 24 is connected to the water outlet of the intermediate water tank 106 for pumping and cleaning; the filtration tank 105 is provided with a filtration partition board and a stirring and flushing device 12, and spherical filtration fillers are filled in the middle; a backwashing discharge water pipeline is arranged at the upper part of the filtration tank 105 and is provided with a valve 26.

[0071] A liquid level meter and an electrolyzer 13 are arranged in the intermediate water tank 106. The electrolyzer 13 is mainly connected to the commercial power supply, and can also be directly powered by the photovoltaic module 4 for assistance, and is controlled in the same way as the electric heater in the anaerobic tank 102. Electrolysis can control the microorganisms and heavy metals in the effluent, and the finally treated water is discharged from the water outlet of the intermediate water tank 106.

[0072] In addition, the control logic of the controller 6 of the present invention is mainly implemented based on the weather in which the light intensity is continuous and presents a single peak during the day. Of course, it can also be used for sudden weather conditions such as thunderstorms, but it is best to base it on the weather forecast and the light intensity forecast. In the event of extreme weather changes that lead to frequent changes in light, the controller 6 can be manually turned off, and the photovoltaic components 4 can also be turned off to avoid system disorder.

[0073] A sewage treatment method of the present invention comprises the following steps:

[0074] The sewage to be treated flows through the anaerobic tank 102, the facultative oxygen tank 101 and the aerobic tank 103 in sequence, and the sewage is heated in the anaerobic tank 102 by using the DC electric heater 2 and the AC electric heater 3, wherein the DC electric heater 2 is directly supplied with DC power by the photovoltaic module 4, and the AC electric heater 3 is supplied with AC power by the mains device 5, and the heating process is as follows:

[0075] When the power of the DC electric heater 2 is less than the set power value, the power of the AC electric heater 3 is controlled and adjusted so that the total power of the DC electric heater 2 and the AC electric heater 3 is maintained within the set total power range for joint heating;

[0076] When the power of DC heater 2 exceeds the set power value, AC heater 3 is controlled to stop working, DC heater 2 heats alone, and controls to increase the water storage capacity in anaerobic tank 102, reduce the water temperature rise rate of anaerobic tank 102, and maintain the water temperature of anaerobic tank 102 within the set temperature range.

[0077] Preferably, the set power value is the upper limit of the set total power range. When the total power of the DC electric heater 2 and the AC electric heater 3 is maintained within the set total power range, and the water storage capacity of the anaerobic tank 102 is at the initial value, the water temperature in the anaerobic tank 102 will be maintained within the set temperature range, and the set temperature range can be: 30-45°C.

[0078] Optionally, after the water storage in the anaerobic tank 102 is increased, when the power of the DC electric heater 2 is less than the set power value, the water storage in the anaerobic tank 102 is controlled to be reduced to the initial value. During the day, the distribution diagram of light intensity over time is roughly in the shape of a wave crest. After the water storage in the anaerobic tank 102 is increased, there will definitely be a light intensity that makes the power of the DC electric heater 2 less than the set power value. At this time, the water storage in the anaerobic tank 102 can be restored to the initial value, on the one hand to prepare for tomorrow's use, and on the other hand to avoid the total water storage being too large and insufficient to maintain the water temperature normal when heating with the set total power.

[0079] Optionally, the value for controlling the increase in the water storage volume in the anaerobic tank 102 is obtained according to the relationship between the predicted light intensity and time on the current day. A scientifically accurate and appropriate value for increasing the water demand is set to eliminate the influence of the current generated by the photovoltaic module fluctuating with the light intensity.

[0080] Optionally, when controlling and adjusting the change in the water storage volume in the anaerobic tank 102, the water storage volumes of the anoxic tank 101 and / or the aerobic tank 103 are adjusted simultaneously so that the total water storage volume of the anoxic tank 101, the anaerobic tank 102, and the aerobic tank 103 remains unchanged, thereby keeping the water outlet rate of the aerobic tank 103 within the set speed range and reducing the influence on the water outlet rate.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the scope of its protection. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that after reading the present invention, various changes, modifications, or equivalent replacements can still be made to the specific implementation manners of the invention. However, these changes, modifications, or equivalent replacements are all within the scope of the claims of the invention pending approval.

Claims

1. A sewage treatment system, characterized in that, It includes an anaerobic pond (102), an anoxic pond (101) and an aerobic pond (103) connected in sequence. The water storage capacity of the anaerobic pond (102) can be adjusted, and a DC electric heater (2) and an AC electric heater (3) are provided inside. It also includes a photovoltaic module (4), a mains power device (5) and a controller (6). The photovoltaic module (4) is used to convert solar energy into electric energy and directly supply direct current to the DC electric heater (2). The mains power device (5) is used to supply industrial frequency alternating current to the AC electric heater (3). The controller (6) includes a power control module (61) and a water storage capacity control module (62). The power control module (61) is used to control and adjust the power of the AC electric heater (3) when the power of the DC electric heater (2) is less than the set power value, so that the total power of the DC electric heater (2) and the AC electric heater (3) is maintained within the set total power range. The water storage capacity control module (62) is used to control the AC electric heater (3) to stop working when the power of the DC electric heater (2) is not less than the set power value, and control to increase the water storage capacity in the anaerobic pond (102) to reduce the water temperature rise rate in the anaerobic pond (102) and keep the water temperature in the anaerobic pond (102) within the set temperature range; The water storage capacities of the anoxic pond (101) and the aerobic pond (103) can be adjusted, and the water storage capacities of the anoxic pond (101), the anaerobic pond (102) and the aerobic pond (103) are adjusted by adjusting the water storage volume. When the water storage capacity control module (62) controls and adjusts the change in the water storage capacity in the anaerobic pond (102), it simultaneously adjusts the water storage capacity of the anoxic pond (101) and / or the aerobic pond (103) to keep the total water storage capacity of the anoxic pond (101), the anaerobic pond (102) and the aerobic pond (103) unchanged; It also includes a pond body (1). A first adjustable partition (7) and a second adjustable partition (8) are arranged at intervals inside the pond body (1). The first adjustable partition (7) and the second adjustable partition (8) divide the pond body (1) into the anoxic pond (101), the anaerobic pond (102) and the aerobic pond (103) in sequence. The first adjustable partition (7) and the second adjustable partition (8) are controlled and adjusted by the controller (6) to realize the adjustment of the water storage volume of the anaerobic pond (102); The first adjustable partition (7) includes an upper telescopic rotating plate (71), a middle rotating plate (72) and a bottom support plate (73); the bottom support plate (73) is fixed on the bottom surface of the pond body (1); the bottom edge of the middle rotating plate (72) is rotatably arranged on the top edge of the bottom support plate (73), the top edge of the middle rotating plate (72) is rotatably connected to the bottom edge of the upper telescopic rotating plate (71), the top edge of the upper telescopic rotating plate (71) is rotatably arranged on a first rotating shaft (76), and both ends of the first rotating shaft (76) are rotatably arranged on the pond body (1); A telescopic component (74) is arranged on the outer side surface of the upper telescopic rotating plate (71). Driven by the telescopic component (74), the middle rotating plate (72) rotates away from the anaerobic pond (102), and the upper telescopic rotating plate (71) also rotates and extends, expanding the side wall of the anaerobic pond (102) towards the anoxic pond (101), increasing the water storage volume and water storage amount of the anaerobic pond (102). Meanwhile, through linkage adjustment, the water storage volume and water storage amount of the anoxic pond (101) are decreased.

2. The sewage treatment system according to claim 1, characterized in that, The water storage amount control module (62) is further configured to, after controlling and adjusting the increase of the water storage amount in the anaerobic pond (102), when the power of the DC electric heater (2) is less than the set power value, control to decrease the water storage amount in the anaerobic pond (102) to the initial value.

3. A sewage treatment system according to claim 1, characterized in that, It further includes a light intensity forecasting device (9), and the light intensity forecasting device (9) is used to forecast the relationship between the light intensity and time every day. The controller (6) further includes a preset module (63), and the preset module (63) is used to set the increase value of the water storage amount in the anaerobic pond (102) controlled and adjusted on the current day according to the forecast relationship between the light intensity and time every day.

4. A sewage treatment system according to claim 1, characterized in that, A temperature alarm device (10) is arranged inside the anaerobic pond (102), and the temperature alarm device (10) is used to give an alarm when the temperature of the anaerobic pond (102) reaches the maximum temperature value.

5. A sewage treatment system according to claim 1, characterized in that, It further includes a sedimentation and reflux pond (104), a filtration pond (105) and a middle water pond (106) that are sequentially communicated with the water outlet of the aerobic pond (103), and a waste heat recovery device is arranged at the water outlet of the middle water pond (106).

6. A sewage treatment method, which uses the sewage treatment system according to any one of claims 1-5 for sewage treatment, characterized in that, It includes the following steps: Flow the sewage to be treated through the anaerobic pond (102), the anoxic pond (101) and the aerobic pond (103) in sequence, and use the DC electric heater (2) and the AC electric heater (3) to jointly heat the sewage in the anaerobic pond (102). Among them, the DC electric heater (2) is directly supplied with direct current by the photovoltaic module (4), and the AC electric heater (3) is supplied with alternating current by the mains device (5). The heating process is as follows: When the power of the DC electric heater (2) is less than the set power value, control and adjust the power of the AC electric heater (3) so that the total power of the DC electric heater (2) and the AC electric heater (3) is maintained within the set total power range for joint heating. When the power of the DC electric heater (2) is not less than the set power value, control the AC electric heater (3) to stop working, and control to increase the water storage amount in the anaerobic pond (102) to reduce the water temperature rising rate in the anaerobic pond (102) so that the water temperature in the anaerobic pond (102) is maintained within the set temperature range.

7. A sewage treatment method according to claim 6, characterized in that, The value of controlling to increase the water storage amount in the anaerobic pond (102) is obtained according to the forecast relationship between the light intensity and time on the current day.

8. A sewage treatment method according to claim 6, characterized in that, When controlling and adjusting the change in the water storage volume in the anaerobic tank (102), simultaneously adjust the water storage volume of the anoxic tank (101) and / or the aerobic tank (103) so that the total water storage volume of the anoxic tank (101), the anaerobic tank (102), and the aerobic tank (103) remains unchanged.

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