Automatic cooling control method and device for wastewater treatment biochemical system

Abstract

The invention discloses an automatic cooling control method and device for a wastewater treatment biochemical system, and the control method comprises the steps: obtaining the heat exchange amount required for cooling the biochemical system to a target temperature according to the water inlet heat effect, the water pump heat effect, the biochemical reaction heat release amount and the blast aeration heat conduction heat of the biochemical system; the biochemical sewage circulation flow and the cooling water circulation flow required during heat exchange are obtained according to the required heat exchange amount; and finally, adjusting the flow of the biochemical sewage circulating pump according to the required biochemical sewage circulating flow, and adjusting the flow of the cooling water circulating pump according to the required cooling water circulating flow. According to the control method, multiple influence factors of the biochemical system are integrated, control is accurate and reliable, automatic control can be achieved, energy loss caused by personal errors is reduced, and the labor cost is also reduced. The control device based on the automatic cooling control method for the wastewater treatment biochemical system is easy to operate, high in automation degree and capable of automatically and accurately regulating and controlling the temperature parameters of the biochemical pool.

Description

Technical Field

[0001] The invention belongs to the technical field of wastewater treatment, and in particular relates to an automatic temperature reduction control method and device for a wastewater treatment biochemical system. Background Art

[0002] At present, the treatment process of landfill leachate mostly adopts membrane biochemical reactor (MBR) process. Compared with traditional biochemical water treatment technology, membrane biochemical reactor has the advantages of high volume load, high treatment efficiency, good effluent quality; compact equipment, small footprint; easy to achieve automatic control, simple operation and management. In the process of biochemical degradation, the temperature of activated sludge has a great influence on sludge growth and nitrification. For nitrifying bacteria, the optimal reaction temperature range is 32℃~36℃. Since bacterial cell components such as proteins and nucleic acids are extremely sensitive to temperature, when the temperature rises or falls suddenly and exceeds a certain limit, irreversible damage will occur. When the temperature in the biochemical system is lower than 5℃ or higher than 45℃, the growth of nitrifying bacteria will be inhibited, thereby inhibiting the nitrification reaction. Temperature difference changes in a short period of time will cause problems such as decreased treatment efficiency and increased foam in the biochemical system. The factors that affect the temperature are mainly the following: ⑴ The inlet water heat effect brought by the temperature difference between the leachate and the sludge in the biochemical pool, including the leachate inlet temperature is higher than the sludge temperature in the biochemical pool, which makes the pool temperature rise, or the leachate inlet temperature is lower than the sludge temperature in the biochemical pool, which reduces the heat in the biochemical pool; ⑵ In the process of biochemical degradation, part of the chemical energy is converted into heat energy during the oxidation of organic matter and ammonia nitrogen, and the higher the concentration of activated sludge, the greater the biochemical heat release, so the temperature in the membrane reactor increases; ⑶ Due to the temperature rise of the circulating water pump, fan, etc., as well as environmental radiation and heat dissipation, the air temperature can be increased, especially the mechanical energy of the circulating water pump can be converted into heat energy. In summer operation, the temperature of the biochemical pool can easily exceed 35℃. If the temperature of the biochemical pool cannot be controlled, it will affect the growth of active bacteria, causing the treatment efficiency of the biochemical system to drop sharply, and in severe cases, the biochemical system cannot operate.

[0003] The conventional cooling device of the biochemical system for treating landfill leachate is as follows: Figure 1As shown, it includes a water inlet pump 11, an aeration fan 22 and a heat exchanger 32 respectively connected to the biochemical pool 21, a biochemical sewage circulation pump 31 connected between the biochemical pool 21 and the heat exchanger 32, a cooling tower 34, a cooling water circulation pump 35 connected between the cooling tower 34 and the heat exchanger 32, a water supply pipe 39 connected to the cooling tower 34, and a water supply pump 38 on the water supply pipe 39. The operation mode of the existing cooling device is mainly based on manual operation, and the temperature of the sludge in the system needs to be controlled by starting and stopping the cooling system from time to time. The operation is frequent and has a great relationship with the technical level and professional quality of the on-site operating personnel, which has a great impact on the stable operation of the biochemical system. For example, the Chinese utility model patent CN 202400898U proposes a biochemical cooling device for use in a landfill leachate treatment system. The device includes a sludge circulation pump, a cooling water pump, a cooling tower, a plate heat exchanger and various pipelines. It can achieve the effect of reducing the sludge temperature in the biochemical system reaction tank, but there are problems such as inaccurate temperature control and low degree of automatic control. The existing biochemical system temperature control method is usually: according to the actual temperature in the biochemical system detected by the temperature sensor in the biochemical system, the cooling system is manually started and stopped. The specific operation is as follows: when the detected temperature is close to or higher than 36°C, the cooling system is turned on; when the detected temperature is close to or lower than 32°C, the cooling system is turned off. The problems with the existing control method are: (1) Since the tank capacity of the biochemical system is too large, it is difficult to achieve uniform mixing of water quality in a short period of time. Therefore, when the cooling system is turned off, there is a temperature difference between the cooled local sludge and the uncooled sludge. The two sludges with different heat continue to transfer heat in the tank. Therefore, the temperature in the biochemical system often continues to drop or rise after the cooling system is turned off; (2) The existing sludge cooling pump and cooling water circulation pump are fixed-frequency large-flow pumps. The biochemical system cools down quickly, resulting in a large temperature fluctuation range (28°C to 40°C) in the biochemical system. On the one hand, it reduces the activity of the biochemical sludge and the rate of pollutant degradation. On the other hand, it requires uninterrupted and frequent opening and closing of the cooling system, which brings great inconvenience to the operator; (3) Manual control is subjective, and differences in the technical capabilities of operators will cause unnecessary energy consumption and other uncertain factors; (4) The manual adjustment method of controlling the temperature of the biochemical system has a low degree of automation, which is not conducive to the refined management of energy consumption. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide a method and device for automatically cooling a wastewater treatment biochemical system with precise control and a high degree of automation.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions: A method for automatically cooling a wastewater treatment biochemical system comprises the following steps: S1, obtain the water inlet heat effect Q1, water pump heat effect Q2, biochemical reaction heat release Q3 and aeration heat conduction heat Q4 of the biochemical system; S2, according to the water inlet heat effect Q1, water pump heat effect Q2, biochemical reaction heat release Q3 and aeration heat conduction heat Q4, the heat exchange required for cooling the biochemical system Q sum ; S3, according to the required heat exchange Q sum Get the biochemical sewage circulation flow rate Q required for heat exchange H and required cooling water circulation flow Q C ; S4, according to the required biochemical sewage circulation flow Q H Adjust the flow rate Q of the biochemical sewage circulation pump H1 , according to the required cooling water circulation flow Q C Adjust the cooling water circulation pump flow Q C1 .

[0006] Further improvement: In step S4, the end point of the adjustment is: the required biochemical sewage circulation flow Q H The flow rate Q of the biochemical sewage circulation pump H1 The ratio is 0.95 to 1.05; and / or, the required cooling water circulation flow rate Q C and cooling water circulation pump flow Q C1 The ratio is 0.95~1.05.

[0007] Further improvement: in step S1, the inlet heat effect Q1, the water pump heat effect Q2, the biochemical reaction heat release Q3 and the aeration heat transfer heat Q4 are obtained according to the inlet parameters of the biochemical system, the aeration air inlet parameters, the operating parameters and other relevant parameters; the inlet parameters include the inlet temperature and the inlet flow rate, and also include at least one of the inlet COD value or the inlet BOD value, and at least one of the inlet ammonia nitrogen value or the inlet total nitrogen value; the inlet parameters include the inlet flow rate, and the operating parameters include the temperature of the biochemical sewage in the biochemical pool.

[0008] Further improvement: In step S1, the other relevant parameters include the atmospheric pressure of the area, the denitrification rate of the biochemical system, the control target temperature range of the biochemical sewage, the specific heat capacity of water, the shaft power of the biochemical pool auxiliary water pump, the thermal effect coefficient of nitrification reaction, the thermal effect coefficient of denitrification reaction, the thermal effect coefficient of COD oxidation reaction, the moisture content of the ambient air, the fan blowing temperature, the scale coefficient, the heat transfer coefficient of the heat exchanger, the heat exchange area of ​​the heat exchanger, and the correction coefficient.

[0009] Further improvements: the denitrification rate of the biochemical system is 0.02-0.13NO3-N / kgMLSS / d; the control target temperature range of the biochemical sewage is 32°C-36°C; 50%-99% of the total shaft power of the biochemical pool auxiliary water pump is converted into heat energy; the biochemical pool auxiliary water pump includes an inlet pump, a biochemical sewage circulation pump, a jet pump, a defoaming pump, a nitrate reflux pump and an ultrafiltration reflux pump; the fan blowing temperature is 40°C-150°C.

[0010] Further improvement: In step S2, the formula for obtaining the heat exchange required for cooling the biochemical system is: Q sum =Q1+Q2+Q3+Q4 (1) Among them, Q1 is the heat effect of water inlet, Q2 is the heat effect of water pump, Q3 is the heat released by biochemical reaction, and Q4 is the heat conducted by aeration.

[0011] Further improvement: In step S3, the formula for obtaining the required biochemical sewage circulation flow rate is: Q H =(Q sum / 1.16) / Δt(2) Among them, Q H is the required biochemical sewage circulation flow rate; Q sum is the required heat exchange capacity; Δt is the cooling tower temperature drop.

[0012] Further improvement: The formula for the heat effect of water inlet is: Q1=Q×C 水 × (T1-T2) (1-1) Where, Q is the water inlet flow rate; C 水 is the specific heat capacity of water; T1 is the inlet water temperature; T2 is the temperature of biochemical sewage.

[0013] Further improvement: The formula for the thermal effect of the water pump is: Q2=(P1+P2+P3+P4)×β(1-2) Among them, P1 is the shaft power of the water inlet pump; P2 is the shaft power of the jet pump; P3 is the shaft power of the nitrate reflux pump and the ultrafiltration reflux pump; P4 is the shaft power of the biochemical sewage circulation pump; β is the heat conversion coefficient.

[0014] Further improvement: The formula for the heat release of the biochemical reaction is: Q3=R l +R2+R3 (1-3) Among them, R l R is the heat released by nitrification reaction; R2 is the heat released by denitrification reaction; R3 is the heat released by COD oxidation reaction.

[0015] Further improvement: The formula for the heat release of the nitration reaction is: R l =a×Q×Na(1-3-1) Among them, a is the thermal effect of nitrification reaction; Na is the ammonia nitrogen concentration in the influent.

[0016] Further improvement: The formula for the heat release of the denitrification reaction is: R2=b×Q×Na×γ(1-3-2) Among them, b is the thermal effect of denitrification reaction; γ is the denitrification rate.

[0017] Further improvement: The formula for the heat release of COD oxidation reaction is: R3=c×Q×(S1-S2-S3)(1-3-3) Among them, c is the thermal effect of COD oxidation reaction; S1 is the inlet COD concentration; S2 is the effluent COD concentration; S3 is the inlet BOD concentration.

[0018] Further improvement: The formula for the heat transfer of aeration is: Q4=(h1-h2)×q×r0(1-4) h1=T5+X(2500+1.86×T5) / 1000 h2=0.0023×T2 3 -0.078×T2 2 +3.6857×T2-3.1143 r0=-0.0046×T0+1.2714 Among them, q is the blast air volume; T5 is the fan blast temperature; X is the moisture content of the ambient air; T0 is the ambient temperature.

[0019] Further improvement: the other related parameters also include the maximum conductivity threshold σ of the cooling circulating water max and the minimum threshold σ min The steps also include: obtaining the conductivity value σ of the cooling circulating water, comparing σ with the preset maximum conductivity threshold σ max and the minimum threshold σ min Compare; when σ≥σ max When σ≤σ min When the cooling tower is drained, stop replenishing fresh water.

[0020] As a general inventive concept, the present invention also provides an automatic cooling device for a wastewater treatment biochemical system, comprising a water inlet unit, a biochemical unit, a cooling unit and a control unit, wherein the water inlet unit comprises a water inlet pump, a water inlet pipe and a water inlet parameter detector, wherein the water inlet parameter detector is located on the water inlet pipe and comprises a water inlet temperature sensor, a water inlet flow meter, a COD online detector and an ammonia nitrogen online detector; wherein the biochemical unit comprises a biochemical pool, an aeration fan, an aeration pipe and an air inlet parameter detector, wherein the aeration pipe is used to connect the aeration fan with the biochemical pool, wherein the air inlet parameter detector is located on the aeration pipe and comprises an air inlet flow meter, wherein a biochemical wastewater temperature sensor is also provided in the biochemical pool, and wherein the outlet of the water inlet pipe is connected with the biochemical pool; wherein The cooling unit includes a biochemical sewage circulation pump, a heat exchanger, a biochemical sewage circulation pipe, a cooling tower, a cooling water circulation pump and a cooling water circulation pipe. The biochemical sewage circulation pipe connects the biochemical pool, the biochemical sewage circulation pump and the hot side pipeline of the heat exchanger. The biochemical sewage circulation pipe is provided with a biochemical sewage circulation flowmeter. The cooling water circulation pipe connects the cooling tower, the cooling water circulation pump and the cold side pipeline of the heat exchanger. The cooling water circulation pipe is provided with a cooling water circulation flowmeter; the water inlet parameter detector, the air inlet parameter detector, the biochemical sewage circulation pump and the cooling water circulation pump are respectively connected to the control unit. The control unit is programmed with a control program, and the control program is used to execute the above-mentioned automatic cooling control method for the wastewater treatment biochemical system.

[0021] Further improvement: the cooling unit also includes a conductivity detector, a water supply pump, a water supply pipe and a sewage pipe. The conductivity detector is used to detect the conductivity of the circulating cooling water. The water supply pipe connects the cooling tower and the water supply pump with an external water source. The sewage pipe is located at the bottom of the water collection tank of the cooling tower, and a sewage valve is provided on the sewage pipe. The conductivity detector, the water supply pump and the sewage valve are respectively connected to the control unit or a separately provided controller.

[0022] Compared with the prior art, the advantages of the present invention are: (1) The automatic cooling control method for the wastewater treatment biochemical system of the present invention first obtains the heat exchange required for cooling the biochemical system to the target temperature based on the heat effect of the biochemical system inlet water, the heat effect of the water pump, the heat released by the biochemical reaction and the heat conducted by the aeration, and then obtains the required biochemical sewage circulation flow and the required cooling water circulation flow during heat exchange based on the required heat exchange; finally, the biochemical sewage circulation pump flow is adjusted based on the required biochemical sewage circulation flow, and the cooling water circulation pump flow is adjusted based on the required cooling water circulation flow. The control method of the present invention comprehensively considers multiple key factors affecting the thermal effect of the biochemical system to obtain the target heat exchange required to reduce the temperature to the target temperature. According to the heat balance equivalence relationship, the heat released by the biochemical system during heat exchange is equal to the heat absorbed by the cooling water, and the target circulation flow of the hot side medium and the cold side medium of the heat exchanger is obtained, and the actual circulation flow is adjusted and controlled based on the target circulation flow. Compared with the traditional method of single temperature feedback control through the biochemical pool, the control method of the present invention overcomes the technical defects of the prior art that the feedback parameters and the actual parameters have a large deviation and cannot be accurately controlled due to the large pool capacity and difficulty in mixing in a short time. The control method of the present invention adjusts the actual circulation flow rate by the heat exchange target circulation flow rate. Since many influencing factors are integrated, the control is more accurate and reliable, and can ensure that the temperature in the biochemical pool is in a relatively stable working condition, so that the temperature fluctuation range in the biochemical pool does not exceed 1°C.

[0023] (2) The control method of the present invention controls the circulation flow rate of biochemical wastewater and the circulation flow rate of cooling water when the temperature in the biochemical pool is lowered by means of key parameter signals and logical operations, thereby achieving the purpose of controlling the temperature index in the biochemical pool. The control method can be fully automated and easy to operate, reducing unnecessary energy loss and other uncertain factors caused by differences in the technical capabilities of operators, thereby reducing labor costs.

[0024] (3) The control method of the present invention uses conductivity feedback control to timely replace the cooling circulating water, and monitors and controls the conductivity of the cooling circulating water in real time within an appropriate range to avoid the enrichment of calcium, magnesium and chloride ions in the cooling water due to circulating evaporation, which may lead to scaling and corrosion problems inside the equipment.

[0025] (4) The automatic cooling device for the wastewater treatment biochemical system of the present invention is equipped with a variety of water inlet parameter detectors, air inlet parameter detectors, electrical components and control units on the basis of existing facilities, which are used to implement the control method of the present invention to achieve the effect of accurately regulating the temperature parameters in the biochemical pool. The device of the present invention can realize automatic and accurate regulation of the temperature parameters of the biochemical pool, so that the microorganisms are in a relatively constant temperature condition, improve the activity of the microorganisms and the rate of pollutant degradation, and at the same time, it is simple to operate, which can reduce the energy loss caused by the difference in the technical ability of the operators and reduce the influence of uncertainty factors.

[0026] (5) The device of the present invention adds a conductivity detector, a sewage discharge component, a water replenishment component and a control connection component to the cooling unit. By real-time monitoring and controlling the conductivity index of the cooling circulating water, the concentrated water of the cooling tower is discharged in time and fresh water is added to control the conductivity within an appropriate range, thereby preventing the scaling of calcium and magnesium ions in the heat exchanger and the corrosion of the cooling tower by chloride ions. Because the cooling water will gradually evaporate during the circulation process, the calcium and magnesium ions and chloride ions in the water will be enriched. When enriched to a certain concentration, the calcium and magnesium ions will scale on the inner wall of the heat exchanger, and the chloride ions will have a certain corrosive effect on the cooling tower. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of a cooling device for an existing conventional biochemical system for treating landfill leachate.

[0028] Figure 2 It is a structural schematic diagram of the automatic cooling device for the wastewater treatment biochemical system according to Example 1 of the present invention.

[0029] Legend: 1. Water inlet unit; 11. Water inlet pump; 12. Water inlet pipe; 121. Water inlet temperature sensor; 122. Water inlet flowmeter; 123. COD online detector; 124. Ammonia nitrogen online detector; 2. Biochemical unit; 21. Biochemical pool; 211. Biochemical sewage temperature sensor; 22. Aeration fan; 23. Aeration pipe; 231. Air inlet flowmeter; 3. Cooling unit; 31. Biochemical sewage circulation pump; 32. Heat exchanger; 33. Biochemical sewage circulation pipe; 331. Biochemical sewage circulation flowmeter; 34. Cooling tower; 35. Cooling water circulation pump; 36. Cooling water circulation pipe; 361. Cooling water circulation flowmeter; 37. Conductivity detector; 38. Make-up water pump; 39. Make-up water pipe; 30 Sewage pipe; 301. Sewage valve; 4. Control unit; 5. Controller. DETAILED DESCRIPTION

[0030] The present invention is further described below in conjunction with the accompanying drawings and specific preferred embodiments, but the protection scope of the present invention is not limited thereby.

[0031] In the following examples, unless otherwise specified, the raw materials and instruments used are commercially available, the equipment used is conventional equipment, and the data obtained are the average values ​​of more than three repeated experiments.

[0032] Embodiment 1: The present invention provides a method for automatically cooling a wastewater treatment biochemical system, comprising the following steps: S1, obtain the water inlet heat effect Q1, water pump heat effect Q2, biochemical reaction heat release Q3 and aeration heat conduction heat Q4 of the biochemical system; S2, according to the water inlet heat effect Q1, water pump heat effect Q2, biochemical reaction heat release Q3 and aeration heat conduction heat Q4, the heat exchange required for cooling the biochemical system Q sum ; S3, according to the required heat exchange Q sum Get the biochemical sewage circulation flow rate Q required for heat exchange H and required cooling water circulation flow Q C ; S4, according to the required biochemical sewage circulation flow Q H Adjust the flow rate Q of the biochemical sewage circulation pump H1 , according to the required cooling water circulation flow Q C Adjust the cooling water circulation pump flow Q C1 .

[0033] The control method of this embodiment comprehensively affects multiple key factors affecting the thermal effect of the biochemical system, obtains the target heat exchange required to reduce to the target temperature, and obtains the target circulation flow rate of the hot side medium and the cold side medium of the heat exchange according to the heat balance equivalence relationship. The actual circulation flow rate is adjusted and controlled according to the target circulation flow rate. Compared with the traditional method of single temperature feedback control of the biochemical pool, the control method of this embodiment overcomes the technical defects of the prior art that the feedback parameters and the actual parameters have a large deviation and cannot be accurately controlled due to the large pool capacity and difficulty in mixing evenly in a short time. The control method of this embodiment that adjusts the actual circulation flow rate by the heat exchange target circulation flow rate, due to the comprehensive control of many influencing factors, is more accurate and reliable, and can ensure that the temperature in the biochemical pool is in a relatively stable working condition, so that the temperature fluctuation amplitude in the biochemical pool does not exceed 1°C. The control method of this embodiment has a high degree of automation, reduces the unnecessary energy loss and other uncertain factors caused by differences in the technical capabilities of operators, and thus reduces labor costs.

[0034] In step S4 of this embodiment, the end point of the adjustment is: the flow rate Q of the biochemical sewage circulation pump H1 and the required biochemical sewage circulation flow Q H The ratio is 0.95~1.05.

[0035] In step S1 of this embodiment, the inlet heat effect Q1, the water pump heat effect Q2, the biochemical reaction heat release Q3 and the aeration heat transfer heat Q4 are obtained according to the inlet parameters of the biochemical system, the aeration air inlet parameters, the operating parameters and other relevant parameters; wherein the inlet parameters include the inlet temperature and the inlet flow rate, and also include at least one of the inlet COD value or the inlet BOD value, and one or more of the inlet ammonia nitrogen value or the inlet total nitrogen value; the air inlet parameters include the air inlet flow rate, and the operating parameters include the temperature of the biochemical sewage in the biochemical pool.

[0036] In step S1 of this embodiment, other relevant parameters include the atmospheric pressure of the area, the denitrification rate of the biochemical system, the control target temperature range of the biochemical sewage, the specific heat capacity of water, the shaft power of the water pump attached to the biochemical pool, the thermal effect coefficient of the nitrification reaction, the thermal effect coefficient of the denitrification reaction, the thermal effect coefficient of the COD oxidation reaction, the moisture content of the ambient air, the blower temperature of the fan, the scale coefficient, the heat transfer coefficient of the heat exchanger, the heat exchange area of ​​the heat exchanger, and the correction coefficient.

[0037] Among them, the denitrification rate of the biochemical system is related to the system operating temperature (i.e., the temperature of the biochemical sewage in the biochemical pool), and will fluctuate with the fluctuation of the biochemical sewage temperature; the thermal effect coefficient of nitrification reaction, the thermal effect coefficient of denitrification reaction, and the thermal effect coefficient of COD oxidation reaction are constants; the water content of the ambient air is related to the ambient air humidity and ambient temperature, and the specific data can be found through relevant tables, that is, the corresponding air water content is found according to the ambient temperature; the fan blowing temperature is the outlet temperature of the aeration pipe; the scale coefficient, heat transfer coefficient of the heat exchanger and the heat exchange area vary with the different brands and models of the heat exchanger. The specific data can be found according to the equipment brand or equipment manual, but the scale coefficient and heat transfer coefficient of the same heat exchanger also have fluctuation ranges, which are mainly caused by the service life of the heat exchanger and the scaling condition. The scale coefficient of the heat exchanger in this embodiment ranges from 0.7 to 0.8, and the heat transfer coefficient ranges from 3500W / (m 2 •K)~5000W / (m 2 •K).

[0038] In this embodiment, the denitrification rate of the biochemical system is 0.02-0.13 NO3-N / kgMLSS / d; the control target temperature range of the biochemical sewage is 32°C-36°C; 50%-99% of the total shaft power of the biochemical pool auxiliary water pump is converted into heat energy, and the biochemical pool auxiliary water pump includes an inlet pump, a biochemical sludge circulation pump, a jet pump, a defoaming pump, a nitrate reflux pump and an ultrafiltration reflux pump; the fan blowing temperature is 40°C-150°C.

[0039] In step S2 of this embodiment, the formula for obtaining the heat exchange amount required for cooling the biochemical system is: Q sum =Q1+Q2+Q3+Q4 (1) Among them, Q1 is the heat effect of water inlet, Q2 is the heat effect of water pump, Q3 is the heat released by biochemical reaction, and Q4 is the heat conducted by aeration.

[0040] In step S3 of this embodiment, the formula for obtaining the required biochemical sewage circulation flow rate is: Q H =(Q sum / 1.16) / Δt(2) Among them, Q H is the required biochemical sewage circulation flow rate, m 3 / h;Q sum is the required heat exchange capacity, kW; Δt is the cooling amplitude of the cooling tower, which is 3℃~5℃. In this embodiment, the formula for obtaining the water inlet thermal effect is: Q1=Q×C 水 × (T1-T2) (1-1) Where Q1 is the inlet water thermal effect, kW; Q is the inlet water hourly volume flow, m 3 / h; C 水 is the specific heat capacity of water, 4.2×10 3 J / kg∙℃; T1 is the inlet water temperature, ℃; T2 is the biochemical wastewater temperature, ℃; When the above units are specified, Q1 = Q × 4.2 × (T1 - T2) / 3.6.

[0041] In this embodiment, the formula for obtaining the thermal effect of the water pump is: Q2=(P1+P2+P3+P4)×β(1-2) Among them, Q2 is the thermal effect of the water pump, kW; P1 is the shaft power of the water inlet pump, kW; P2 is the shaft power of the jet pump, kW; P3 is the shaft power of the reflux pump (nitrate reflux pump and ultrafiltration reflux pump), kW; P4 is the shaft power of the biochemical sewage circulation pump, kW; β is the heat conversion coefficient, which ranges from 50% to 99%; Under normal circumstances, the defoaming pump is not turned on and the pump power is small, which has little effect on the total thermal energy and can be ignored.

[0042] In this embodiment, the formula for obtaining the heat release of the biochemical reaction is: Q3=R l +R2+R3 (1-3) Among them, Q3 is the heat released by the biochemical reaction, kW; R l is the heat released by nitrification reaction, kW; R2 is the heat released by denitrification reaction, kW; R3 is the heat released by COD oxidation reaction, kW; In this embodiment, the formula for obtaining the heat release of the nitration reaction is: R l = (a × Q × Na / 1000) / 3600 (1-3-1) Where a is the thermal effect of nitrification reaction, which is 26660 kJ / kgNH4-N; Na is the influent ammonia nitrogen concentration, mg / L; In this embodiment, the formula for obtaining the heat release of the denitrification reaction is: R2=(b×Q×Na×γ / 1000) / 3600(1-3-2) Among them, b is the thermal effect of denitrification reaction, which is 35625 kJ / kgNO3-N; γ is the denitrification rate, %, and denitrification rate = (influent total nitrogen - effluent total nitrogen) / influent total nitrogen; In this embodiment, the formula for obtaining the heat release of the COD oxidation reaction is: R3=(c×Q×(S1-S2-S3) / 1000) / 3600(1-3-3) Among them, c is the thermal effect of COD oxidation reaction, which is 14065 kJ / kgO2; S1 is the inlet COD concentration, mg / L; S2 is the effluent COD concentration, mg / L; S3 is the inlet BOD concentration, mg / L.

[0043] In this embodiment, the formula for obtaining the heat transfer amount of aeration heat is: Q4=(h1-h2)×q×r0(1-4) h1=T5+X(2500+1.86×T5) / 1000 h2=0.0023×T2 3 -0.078×T2 2 +3.6857×T2-3.1143 r0=-0.0046×T0+1.2714 Where, q is the blast air volume, m 3 / h (mass flow rate can also be used, the specific conversion is slightly different); T5 is the fan blast temperature, ℃; X is the ambient air moisture content, g / kg; T0 is the ambient temperature, ℃; In this embodiment, other relevant parameters include the maximum conductivity threshold σ of the cooling circulating water. max and the minimum threshold σ min The step also includes: obtaining the conductivity value σ of the cooling circulating water, comparing σ with the preset maximum conductivity threshold σ max and the minimum threshold σ min Compare; when σ≥σ max When σ≤σ min When , stop draining the cooling tower and stop replenishing fresh water. max is 4500us / cm, σ min The conductivity feedback control method can be used to timely replace the cooling circulating water, and the conductivity of the cooling circulating water can be monitored and regulated in real time within an appropriate range, which can effectively avoid the accumulation of calcium, magnesium and chloride ions in the cooling water due to circulating evaporation, leading to scaling and corrosion inside the equipment.

[0044] Embodiment 2: This embodiment provides an automatic cooling device for a wastewater treatment biochemical system for executing the control method of the present invention, but the device capable of implementing the control method of the present invention is not limited to the automatic cooling device of this embodiment.

[0045] An automatic cooling device for a wastewater treatment biochemical system, such as Figure 2 As shown, it includes a water inlet unit 1, a biochemical unit 2, a cooling unit 3 and a control unit 4. The water inlet unit 1 includes a water inlet pump 11, a water inlet pipe 12 and a water inlet parameter detector. The water inlet parameter detector is located on the water inlet pipe 12 and includes an inlet temperature sensor 121, an inlet flow meter 122, a COD online detector 123 and an ammonia nitrogen online detector 124. The biochemical unit 2 includes a biochemical pool 21, an aeration fan 22, an aeration pipe 23 and an air intake parameter detector. The aeration pipe 23 is used to connect the aeration fan 22 with the biochemical pool 21. The aeration pipe 23 is an outlet main pipe of the aeration fan 22. The air intake parameter detector is located on the aeration pipe 23 and includes an air intake flow meter 231. A biochemical sewage temperature sensor 211 is also provided in the biochemical pool 21. The outlet of the water inlet pipe 12 is connected to the biochemical pool 21, and is used to introduce the landfill leachate to be treated into the biochemical pool 21. The cooling unit 3 includes a biochemical sewage circulation pump 31, a heat exchanger 32, a biochemical sewage circulation pipe 33, a cooling tower 34, a cooling water circulation pump 35 and a cooling water circulation pipe 36. The biochemical sewage circulation pipe 33 connects the biochemical pool 21, the biochemical sewage circulation pump 31 and the hot side pipe of the heat exchanger 32. The biochemical sewage circulation pipe 33 is provided with a biochemical sewage circulation flowmeter 331. The cooling water circulation pipe 36 connects the cooling tower 34, the cooling water circulation pump 35 and the cold side pipe of the heat exchanger 32. The cooling water circulation pipe 36 is provided with a cooling water circulation flowmeter 361. The water inlet parameter detector, the air inlet parameter detector, the biochemical sewage circulation pump 31, and the cooling water circulation pump 35 are respectively connected to the control unit 4. The control unit 4 is programmed with a control program, which is used to execute the automatic cooling control method of the wastewater treatment biochemical system in Example 1.

[0046] In this embodiment, the working process of the automatic cooling device is introduced by taking the biochemical system for treating landfill leachate as an example, but it is not limited to this. In fact, the automatic cooling device of this embodiment is applicable to all MBR biochemical systems under similar water quality. The specific working process includes the following steps: S1. The inlet temperature, inlet flow rate, inlet COD concentration and inlet ammonia nitrogen concentration of the landfill leachate entering the biochemical pool 21 are measured by an inlet parameter detector, the inlet air flow rate entering the biochemical pool 21 is detected by an inlet parameter detector, and the temperature of the biochemical sewage is detected by a biochemical sewage temperature sensor 211, and the inlet temperature parameter control signal ①, the inlet flow parameter control signal ②, the inlet COD parameter control signal ③ and the inlet ammonia nitrogen parameter control signal ④, the inlet air flow parameter control signal ⑤ and the detection temperature control signal ⑥ of the biochemical sewage are transmitted to the control unit 4 respectively.

[0047] S2. After receiving the control signals ①②③④⑤⑥, the control unit 4 calculates the heat exchange Q required by the biochemical system (specifically the biochemical pool 21) in combination with other preset parameter control signals. sum .

[0048] S3, according to the required heat exchange Q sum Calculate the biochemical sewage circulation flow rate Q required for heat exchange H and required cooling water circulation flow Q C .

[0049] S4, control unit 4 according to the required biochemical sewage circulation flow Q H Send a first frequency control signal ⑦ to the biochemical sewage circulation pump 31, according to the required cooling water circulation flow Q C The second frequency control signal ⑩ is sent to the cooling water circulation pump 35, and the biochemical sewage circulation flow meter 331 detects the flow rate Q H1 The signal ⑧ is fed back to the control unit 4, and the cooling water circulation flow meter 361 detects the flow Q C1 The signal ⑨ is fed back to the control unit 4, and the biochemical sewage circulation pump 31 and the cooling water circulation pump 35 respectively adjust the opening frequency of the biochemical sewage circulation pump 31 and the cooling water circulation pump 35 according to the received first frequency control signal ⑦ and the second frequency control signal ⑩, and the real-time flow rate Q detected after adjustment is H1 Signal⑧ and real-time traffic Q C1 The signal ⑨ is fed back to the control unit 4, and the control unit 4 performs multiple cycles of calculation until the biochemical sewage circulation flow meter 331 feeds back the flow rate Q H1 The required biochemical sewage circulation flow Q calculated by the control unit 4 H When the ratio is between 0.95 and 1.05, the frequency adjustment of the biochemical sewage circulation pump 31 and the cooling water circulation pump 35 is stopped.

[0050] Among them, the temperature control range of the inlet water temperature sensor 121 is 0-60°C (i.e., the detectable range of the inlet water temperature sensor 121), and the inlet water flowmeter 122 adopts an electromagnetic flowmeter with a 4mA-20mA output signal. The COD online detector 123 adopts the potassium dichromate method, the single detection time does not exceed 45min, the detection limit is not less than 15mg / L, and it is equipped with an automatic sampling device and a 4mA-20mA output signal. The ammonia nitrogen online detector 124 adopts the salicylic acid method, the single detection time does not exceed 40min, the detection limit is not less than 1mg / L, and it is equipped with an automatic sampling device and a 4mA-20mA output signal. The biochemical pool 21 is a closed biochemical pool, the air inlet flowmeter 231 has a 4mA-20mA output signal, and the temperature control range of the biochemical sewage temperature sensor 211 is 0-60°C (i.e., the detectable range of the biochemical sewage temperature sensor 211). This embodiment realizes online real-time detection of parameters of the biochemical system by adding detectors of COD, ammonia nitrogen, flow rate, temperature and other parameters on the basis of existing equipment and facilities, laying a foundation for realizing automatic control.

[0051] In this embodiment, the diameters of the biochemical sewage circulation pipe 33 and the cooling water circulation pipe 36 are equal, and the biochemical sewage circulation pump 31 and the cooling water circulation pump 35 are set to be interlocked and controlled to be opened and closed at the same time, and both are additionally provided with frequency converters for frequency conversion control, wherein the specific heat capacity of the biochemical sewage is approximately equal to the specific heat capacity of the cooling water. Thus, the opening or closing of the two pumps can be automatically controlled in an interlocked manner to reduce manual misoperation and avoid energy loss caused by opening one pump and closing the other pump.

[0052] In this embodiment, the cooling unit 3 further includes a conductivity detector 37, a water supply pump 38, a water supply pipe 39, a sewage pipe 30 and a controller 5 such as a PLC. The conductivity detector 37 is used to detect the conductivity of the circulating cooling water. The water supply pipe 39 connects the cooling tower 34 and the water supply pump 38 with an external water source (such as recycled water produced by the system). The sewage pipe 30 is located at the bottom of the water collection tank of the cooling tower 34, and a sewage valve 301 is provided on the sewage pipe 30. The conductivity detector 37, the water supply pump 38, and the sewage valve 301 are respectively connected to the controller 5. Of course, in other embodiments, the controller 5 may not be provided, and the conductivity detector 37, the water supply pump 38, and the sewage valve 301 are respectively connected to the control unit 4. The device of this embodiment is provided with a conductivity detector 37, a sewage discharge component, a water replenishment component and a control connection component in the cooling unit 3. By real-time monitoring and controlling the conductivity index of the cooling circulating water, the concentrated water of the cooling tower 34 is discharged in time and fresh water is added to control the conductivity within an appropriate range, so as to prevent the scaling of calcium and magnesium ions in the heat exchanger 32 and the corrosion of the cooling tower 34 by chloride ions. Because the cooling water will gradually evaporate during the circulation process, the calcium and magnesium ions and chloride ions in the water will be enriched. When enriched to a certain concentration, the calcium and magnesium ions will scale on the inner wall of the heat exchanger 32, and the chloride ions will have a certain corrosive effect on the cooling tower 34.

[0053] In this embodiment, the conductivity detector 37 is arranged at the water outlet of the cooling tower 34, with a measurement accuracy range of 0 to 5000 us / cm, and has a 4mA to 20mA output signal and an upper limit alarm function.

[0054] The process of controller 5 controlling the cooling circulating water is as follows: (1) When the controller 5 receives the signal value σ≥σ output by the conductivity detector 37 max When the drain valve 301 of the cooling tower 34 and the water supply pump 38 of the cooling tower 34 are opened successively, wherein σ max =4500us / cm, which is the preset maximum conductivity threshold; (2) When the controller 5 receives the signal value σ≤σ output by the conductivity detector 37 min When the cooling tower drain valve 301 and the cooling tower 34 water supply pump 38 are closed successively, σ min =2000us / cm, which is the preset minimum conductivity threshold.

[0055] Taking the biochemical system of landfill leachate in a garbage treatment plant in a city in the central and southern regions as an example, the automatic cooling device of this embodiment is used to automatically cool down the landfill leachate biochemical system. The specific parameters involved in the actual operation process are as follows: In step S1, the measured water inlet parameters are: water inlet temperature 40°C, water inlet flow rate 62.5m 3 / h, inlet COD concentration 11000mg / L, inlet BOD concentration 5000mg / L, effluent COD concentration 800mg / L, inlet ammonia nitrogen concentration 3200mg / L; The measured intake parameters are: intake flow rate 18239m 3 / h; The measured operating parameters of the biochemical system were: the temperature of the leachate in the biochemical pool was 32°C; Other relevant parameters are set as follows: denitrification rate 0.128NO3-N / kgMLSS / d, target temperature range of biochemical sewage 32℃~36℃, total power of auxiliary water pumps of biochemical pool 21 including water inlet pump, biochemical sludge circulation pump, jet pump, defoaming pump, nitrate reflux pump and ultrafiltration reflux pump is 772kw (the defoaming pump has a shorter opening time and a smaller pump power, which has little effect on the total heat energy and can be ignored), assuming that 85% of the shaft power of the auxiliary water pump is converted into heat energy, nitrification reaction Thermal effect is 26660 kJ / kgNH4-N, thermal effect of denitrification reaction is 35625 kJ / kgNO3-N, thermal effect of CODcr oxidation reaction is 14065 kJ / kgO2; total nitrogen in inlet is 4000 mg / L, total nitrogen in outlet is 40 mg / L, then denitrification rate is 99%; ambient air moisture (humidity) is 22 g / kg, machine blast temperature is 100 °C, ambient temperature is 40 °C, scale coefficient is 0.75, heat transfer coefficient is 3500 W / (m 2 •K), heat exchange area 645m 2 , Δt is 3.5℃.

[0056] The control unit 4 calculates based on the above parameters and the preset formula: Q1=583kw, Q2=656kw, Q3=4710kw, Q4=268kw, and the heat exchange required by the biochemical system Q sum =6217kw, required biochemical sewage circulation flow Q H =1531m 3 / h, required cooling water circulation flow Q C =1531m 3 / h.

[0057] By real-time monitoring of the temperature parameters in the biochemical pool by the temperature sensor, it can be known that the automatic cooling device of this embodiment obtains the required theoretical heat exchange rate by comprehensively considering multiple key factors that affect the thermal effect of the biochemical system, and further obtains the theoretical circulation flow rate of the cold and hot media during heat exchange. The flow rates of the biochemical sewage circulation pump 31 and the cooling water circulation pump 35 are controlled according to the theoretical circulation flow rates of the cold and hot media of the heat exchanger to maintain the temperature in the biochemical system at a relatively constant working condition. The control is precise, and the temperature fluctuation amplitude in the biochemical pool basically does not exceed 1°C. The degree of automation is high, energy damage caused by human operation is avoided, and labor costs are reduced.

[0058] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any technician familiar with the art can make many possible changes and modifications to the technical solution of the present invention by using the technical content disclosed above without departing from the scope of the technical solution of the present invention, or modify it into an equivalent embodiment of equivalent changes. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention should fall within the scope of protection of the technical solution of the present invention.

Claims

1. A method for automatically cooling a wastewater treatment biochemical system, characterized in that: The following steps are involved: S1, obtain the water inlet heat effect Q1, water pump heat effect Q2, biochemical reaction heat release Q3 and aeration heat conduction heat Q4 of the biochemical system; S2, according to the water inlet heat effect Q1, water pump heat effect Q2, biochemical reaction heat release Q3 and aeration heat conduction heat Q4, the heat exchange required for cooling the biochemical system Q sum ; S3, according to the required heat exchange Q sum Get the biochemical sewage circulation flow rate Q required for heat exchange H and required cooling water circulation flow Q C ; S4, according to the required biochemical sewage circulation flow Q H Adjust the flow rate Q of the biochemical sewage circulation pump H1 , according to the required cooling water circulation flow Q C Adjust the cooling water circulation pump flow Q C1 .

2. The automatic temperature reduction control method for wastewater treatment biochemical system according to claim 1, characterized in that: In step S4, the end point of the adjustment is: the required biochemical sewage circulation flow rate Q H The flow rate Q of the biochemical sewage circulation pump H1 The ratio is 0.95 to 1.05; and / or, the required cooling water circulation flow rate Q C and cooling water circulation pump flow Q C1 The ratio is 0.95~1.

05.

3. The automatic temperature reduction control method for wastewater treatment biochemical system according to claim 2 is characterized in that: In step S1, the inlet heat effect Q1, the water pump heat effect Q2, the biochemical reaction heat release Q3 and the aeration heat conduction heat Q4 are obtained according to the inlet parameters of the biochemical system, the aeration air inlet parameters, the operating parameters and other relevant parameters; the inlet parameters include the inlet temperature and the inlet flow rate, and also include at least one of the inlet COD value or the inlet BOD value, and at least one of the inlet ammonia nitrogen value or the inlet total nitrogen value; the inlet parameters include the inlet flow rate, and the operating parameters include the temperature of the biochemical sewage in the biochemical pool.

4. The automatic temperature reduction control method for wastewater treatment biochemical system according to claim 3 is characterized in that: In step S1, the other relevant parameters include the atmospheric pressure of the area, the denitrification rate of the biochemical system, the control target temperature range of the biochemical sewage, the specific heat capacity of water, the shaft power of the biochemical pool auxiliary water pump, the thermal effect coefficient of nitrification reaction, the thermal effect coefficient of denitrification reaction, the thermal effect coefficient of COD oxidation reaction, the moisture content of the ambient air, the blast temperature of the fan, the scale coefficient, the heat transfer coefficient of the heat exchanger, the heat exchange area of ​​the heat exchanger, and the correction coefficient; The denitrification rate of the biochemical system is 0.02-0.13 NO3-N / kgMLSS / d, the control target temperature range of the biochemical sewage is 32°C-36°C, 50%-99% of the total shaft power of the biochemical pool auxiliary water pump is converted into heat energy, and the biochemical pool auxiliary water pump includes an inlet pump, a biochemical sewage circulation pump, a jet pump, a defoaming pump, a nitrate reflux pump and an ultrafiltration reflux pump; the fan blowing temperature is 40°C-150°C.

5. The automatic temperature reduction control method for a wastewater treatment biochemical system according to any one of claims 1 to 4, characterized in that: In step S2, the formula for obtaining the heat exchange amount required for cooling the biochemical system is: <h2 style=";text-align:left;direction:ltr">Q<h2 style=";text-align:left;direction:ltr"> sum <h2 style=";text-align:left;direction:ltr"> =Q1+Q2+Q3+Q4(1) Among them, Q1 is the heat effect of water inlet, Q2 is the heat effect of water pump, Q3 is the heat released by biochemical reaction, and Q4 is the heat conducted by aeration.

6. The automatic temperature reduction control method for wastewater treatment biochemical system according to claim 5, characterized in that: In step S3, the formula for obtaining the required biochemical sewage circulation flow rate is: Q H =(Q sum / 1.16) / Δt(2) Among them, Q H is the required biochemical sewage circulation flow rate; Q sum is the required heat exchange capacity; Δt is the cooling tower temperature drop.

7. The automatic temperature reduction control method for wastewater treatment biochemical system according to claim 6, characterized in that: The formula for the heat effect of water inlet is: Q1=Q×C 水 ×(T1-T2)(1-1) Where, Q is the water inlet flow rate; C 水 is the specific heat capacity of water; T1 is the inlet water temperature; T2 is the biochemical sewage temperature; The formula for the thermal effect of the water pump is: Q2=(P1+P2+P3+P4)×β(1-2) Among them, P1 is the shaft power of the water inlet pump; P2 is the shaft power of the jet pump; P3 is the shaft power of the nitrate reflux pump and the ultrafiltration reflux pump; P4 is the shaft power of the biochemical sewage circulation pump; β is the heat conversion coefficient; The formula for obtaining the heat released by the biochemical reaction is: Q3=R l +R2+R3(1-3) Among them, R l R is the heat released by nitrification reaction; R2 is the heat released by denitrification reaction; R3 is the heat released by COD oxidation reaction; The formula for the heat released by the nitration reaction is: R l =a×Q×Na(1-3-1) Where a is the thermal effect of nitrification reaction; Na is the ammonia nitrogen concentration in the influent; The formula for the heat released by the denitrification reaction is: R2=b×Q×Na×γ(1-3-2) Wherein, b is the thermal effect of denitrification reaction; γ is the denitrification rate; The formula for obtaining the heat released by the COD oxidation reaction is: R3=c×Q×(S1-S2-S3)(1-3-3) Wherein, c is the heat effect of COD oxidation reaction; S1 is the influent COD concentration; S2 is the effluent COD concentration; S3 is the influent BOD concentration; The formula for obtaining the heat transfer of aeration is: Q4=(h1-h2)×q×r0(1-4) h1=T5+X(2500+1.86×T5) / 1000 h2=0.0023×T2 3 -0.078×T2 2 +3.6857×T2-3.1143 r0=-0.0046×T0+1.2714 Among them, q is the blast air volume; T5 is the fan blast temperature; X is the moisture content of the ambient air; T0 is the ambient temperature.

8. The automatic temperature reduction control method for wastewater treatment biochemical system according to claim 1 is characterized by: The other relevant parameters also include the maximum conductivity threshold σ of the cooling circulating water max and the minimum threshold σ min The steps also include: obtaining the conductivity value σ of the cooling circulating water, comparing σ with the preset maximum conductivity threshold σ max and the minimum threshold σ min Compare; when σ≥σ max When σ≤σ min When the cooling tower is drained, stop replenishing fresh water.

9. An automatic cooling device for a wastewater treatment biochemical system, comprising a water inlet unit (1), a biochemical unit (2), a cooling unit (3) and a control unit (4), characterized in that: The water inlet unit (1) comprises a water inlet pump (11), a water inlet pipe (12) and a water inlet parameter detector; the water inlet parameter detector is located on the water inlet pipe (12) and comprises a water inlet temperature sensor (121), a water inlet flow meter (122), a COD online detector (123) and an ammonia nitrogen online detector (124); The biochemical unit (2) comprises a biochemical pool (21), an aeration fan (22), an aeration pipe (23) and an air intake parameter detector. The aeration pipe (23) is used to connect the aeration fan (22) with the biochemical pool (21). The air intake parameter detector is located on the aeration pipe (23) and comprises an air intake flow meter (231). A biochemical sewage temperature sensor (211) is also provided in the biochemical pool (21). The outlet of the water inlet pipe (12) is connected to the biochemical pool (21); The cooling unit (3) comprises a biochemical sewage circulation pump (31), a heat exchanger (32), a biochemical sewage circulation pipe (33), a cooling tower (34), a cooling water circulation pump (35) and a cooling water circulation pipe (36); the biochemical sewage circulation pipe (33) connects the biochemical pool (21), the biochemical sewage circulation pump (31) and the hot side pipe of the heat exchanger (32); the biochemical sewage circulation pipe (33) is provided with a biochemical sewage circulation flow meter (331); the cooling water circulation pipe (36) connects the cooling tower (34), the cooling water circulation pump (35) and the cold side pipe of the heat exchanger (32); the cooling water circulation pipe (36) is provided with a cooling water circulation flow meter (361); The water inlet parameter detector, the air inlet parameter detector, the biochemical sewage circulation pump (31), and the cooling water circulation pump (35) are respectively connected to a control unit (4). The control unit (4) is programmed with a control program, and the control program is used to execute the automatic temperature reduction control method for a wastewater treatment biochemical system according to any one of claims 1 to 8.

10. The automatic cooling device for wastewater treatment biochemical system according to claim 9, characterized in that: The cooling unit (3) further comprises a conductivity detector (37), a water supply pump (38), a water supply pipe (39) and a sewage discharge pipe (30); the conductivity detector (37) is used to detect the conductivity of the circulating cooling water; the water supply pipe connects the cooling tower (34) and the water supply pump (38) with an external water source; the sewage discharge pipe (30) is located at the bottom of the water collection tank of the cooling tower (34); and a sewage discharge valve (301) is provided on the sewage discharge pipe (30); the conductivity detector (37), the water supply pump (38) and the sewage discharge valve (301) are respectively connected to the control unit (4) or a separately provided controller (5).

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