A control method of a city double water source water purification system

Abstract

The present application relates to water purification process technical field, especially a kind of control method of urban double water source water purification system, the water quality condition of the raw water is monitored, different water quality condition raw water uses different water treatment control method, reach for different water quality raw water using a set of processing system can be accurately handled effect, the method provided by the present application not only can be treated to reach water standard for raw water, and can accurately control the use of CO2, coagulant in processing process, reduce the maintenance cost and material cost of entire production process.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of water purification process, and particularly relates to a control method of a city double water source water purification system. BACKGROUND

[0002] At present, in the water treatment process of city water supply, an aluminum coagulant is generally used to treat suspended solids, particles and the like in water, but when the pH value of raw water is high, there are many aluminum ions remaining in the water body after coagulation treatment, and high concentration of aluminum ions can cause damage to the membrane treatment device downstream of the flocculation device, increasing the production cost and maintenance cost. For this problem, the main response methods currently adopted are to add acid coagulant, increase the dosage of coagulant, or directly add acid to the raw water to reduce the pH value. However, the above methods all have disadvantages: the use of acid coagulant and the increase of coagulant dosage will increase the production cost, the residual aluminum in the effluent is difficult to control, there is still a risk of exceeding the standard, and the frequent switching of coagulants is not conducive to the stable operation of the water plant process; the raw water acidification method needs to build an acidification system, which has large engineering investment, and strong acid has corrosive properties, which has safety hazards.

[0003] In the prior art, there is an operation of adjusting the pH value of water by adding CO2 to reduce the concentration of aluminum ions, which avoids the corrosion of liquid strong acids such as sulfuric acid and hydrochloric acid to the production equipment of the water plant, and the pollution to the raw water. However, for water supply using wetlands and lake water as water sources, there is high turbidity, more microorganisms and plant tissues in the raw water, and this feature is influenced by seasonality or climate, so it is necessary to increase the amount of coagulant used during water treatment. At this time, if only the amount of CO2 added is simply increased, it is difficult to ensure accurate control of the pH value and aluminum ions, which will increase the maintenance cost, labor cost and material cost in the production process.

[0004] Therefore, it is necessary to provide a control system and control method for accurately treating different water quality raw water, to promote the coagulation and sedimentation effect and reduce the concentration of aluminum ions by realizing more accurate CO2 addition control, to avoid damage to various membrane materials in the subsequent process, and to promote the effective operation of the entire water purification process. SUMMARY

[0005] The present application provides a control method of a city double water source water purification system to realize the treatment of raw water with different water quality conditions and accurate control of the materials used during the treatment process. The specific technical solutions are as follows:

[0006] In a first aspect, the present application provides a control method of a city double water source water purification system, the city double water source water purification system comprising a pre-ozone treatment pool, a coagulation sedimentation pool, a sand filter pool, an ozone activated carbon filter pool, an ultrafiltration membrane filter pool and an automatic control system connected in sequence; the water inlet end of the pre-ozone treatment pool is provided with double raw water inlet pipes;

[0007] The control method comprises:

[0008] monitoring the water quality condition of the double raw water inlet pipes, and judging whether the raw water is type I raw water or type II raw water according to the pH value data of the raw water;

[0009] The type I raw water adopts a control method I, which comprises:

[0010] I-S1: taking the type I raw water as a water sample to obtain a first theoretical relationship curve between the pH value and the CO2 aeration amount, and a second theoretical relationship curve between the turbidity and the coagulant addition amount;

[0011] I-S2: monitoring the pH value and the turbidity of the water inlet of the coagulation sedimentation pool, the pH value of the water inlet of the ozone activated carbon filter pool, the pH value of the water inlet of the ultrafiltration membrane filter pool, and the turbidity of the water outlet of the coagulation sedimentation pool in real time;

[0012] I-S3: calling the pH value data of I-S2, obtaining the real-time CO2 aeration amount in the coagulation sedimentation pool, the ozone activated carbon filter pool and the ultrafiltration membrane filter pool according to the first theoretical relationship curve; calling the turbidity data of I-S2, and obtaining the real-time coagulant addition amount in the coagulation sedimentation pool according to the second theoretical relationship curve;

[0013] I-S4: controlling the discharge amount of CO2 in the ozone activated carbon filter pool and the ultrafiltration membrane filter pool, and the discharge amount of CO2 and the addition amount of coagulant in the coagulation sedimentation pool according to the real-time CO2 aeration amount and the real-time coagulant addition amount obtained in I-S3;

[0014] The type II raw water adopts a control method II, which comprises:

[0015] II-S1: obtaining the following data information:

[0016] 1) taking the type II raw water as a water sample to obtain a first deviation relationship curve between the pH value and the CO2 aeration amount;

[0017] 2) a CO2 average deviation coefficient;

[0018] 3) taking the type II raw water as a water sample to obtain a second deviation relationship curve between the turbidity and the coagulant addition amount;

[0019] 4) a coagulant average deviation coefficient;

[0020] II-S2: Real-time monitoring of pH value at the inlet of coagulation sedimentation tank, pH value at the inlet of ozone activated carbon filter tank, pH value at the inlet of membrane filter tank, and turbidity at the outlet of coagulation sedimentation tank;

[0021] II-S3: Substituting the pH value data of II-S2 into the first deviation relationship curve to obtain the real-time deviation aeration amount of CO2 in the coagulation sedimentation tank, ozone activated carbon filter tank and ultrafiltration membrane filter tank, and then obtaining the real-time correction aeration amount of CO2 according to the average deviation coefficient of CO2;

[0022] Substituting the turbidity data of II-S2 into the second deviation relationship curve to obtain the real-time deviation addition amount of coagulant, and then calculating the real-time correction addition amount of coagulant in the coagulation sedimentation tank according to the average deviation coefficient of coagulant set inside;

[0023] II-S4: According to the real-time correction aeration amount of CO2 and the real-time correction addition amount of coagulant obtained by II-S3, controlling the discharge amount of CO2 in the ozone activated carbon filter tank and the ultrafiltration membrane tank, and the discharge amount of CO2 and the addition amount of coagulant in the coagulation sedimentation tank.

[0024] Further, in I-S1, the first theoretical relationship curve is obtained by: taking I-type raw water as a water sample, preparing simulated water sample I with different pH values, exposing CO2 gas into the simulated water sample I, measuring the changes of pH value and CO2 aeration amount, and establishing the first theoretical relationship curve between pH value and CO2 aeration amount;

[0025] The second theoretical relationship curve is obtained by: taking I-type raw water as a water sample, adding aluminum salt coagulant to it, measuring the changes of turbidity and coagulant addition amount, and establishing the second theoretical relationship curve between turbidity and coagulant addition amount.

[0026] Further, in II-S1, the first deviation relationship curve is obtained by: taking II-type raw water as a water sample, exposing CO2 gas into it, measuring the changes of pH value and CO2 aeration amount, and establishing the first deviation relationship curve between pH value and CO2 aeration amount;

[0027] The second deviation relationship curve is obtained by: taking II-type raw water as a water sample, adding aluminum salt coagulant to it, measuring the changes of turbidity and coagulant addition amount, and establishing the second deviation relationship curve between turbidity and coagulant addition amount.

[0028] Further, in II-S1, the method for obtaining the average deviation coefficient of CO2 is:

[0029] The standard effluent of the raw water treatment of type II is used as the water sample to establish a third theoretical relationship curve between pH value and CO2 aeration amount; the raw water of type II is used as the water sample to establish a first deviation relationship curve between pH value and CO2 aeration amount;

[0030] According to formula (1), the average deviation coefficient of CO2 is calculated;

[0031] (1);

[0032] wherein, represents the average deviation coefficient of CO2; i represents the numerical value of the change of pH value in the simulated water sample II, i is from high to low, the initial value of i is the initial pH value of the simulated water sample II, generally 7.5-9.0, n is the lowest value after the pH value decreases, generally 6.0-7.0; N represents the determination times of pH value and corresponding CO2 deviation aeration amount in the process of the decrease of pH from i to n; represents the CO2 deviation aeration amount when the pH value is i, which is obtained through the first deviation relationship curve; represents the CO2 theoretical aeration amount when the pH value is i, which is obtained through the third theoretical relationship curve.

[0033] Further, in II-S1, the method for obtaining the average deviation coefficient of the coagulant is:

[0034] The standard effluent of the raw water treatment of type II is used as the water sample to establish a fourth theoretical relationship curve between turbidity and coagulant addition amount, to establish a fifth theoretical relationship curve between Al 3+ concentration and coagulant addition amount; the raw water of type II is used as the water sample to establish a second deviation relationship curve between turbidity and coagulant addition amount;

[0035] According to formula (2), the average deviation coefficient of the coagulant is calculated;

[0036] (2);

[0037] wherein, represents the average deviation coefficient of the coagulant; j represents the numerical value of the change of turbidity in the simulated water sample II, j is from high to low, the initial value of j is the initial turbidity value of the simulated water sample II, generally 20.0-25.0, m is the lowest value after the turbidity decreases, generally 0-1.0; M represents the determination times of turbidity and corresponding coagulant addition amount in the process of the decrease of turbidity from j to m; the coagulant deviation addition amount D dj represents the coagulant deviation addition amount when the turbidity is j in the second deviation relationship curve; D tj represents the coagulant theoretical addition amount when the turbidity is j.

[0038] Further, in II-S4, the formula for real-time correction of the aeration amount of CO2 is: real-time correction of the aeration amount of CO2 = real-time deviation of the aeration amount of CO2 x average deviation coefficient of CO2.

[0039] The formula for real-time correction of the coagulant addition amount is: real-time correction of the coagulant addition amount = real-time deviation of the coagulant addition amount x average deviation coefficient of the coagulant.

[0040] In a second aspect, the present application provides a city double water source water purification system, comprising: a pre-ozone treatment pool, a coagulation sedimentation pool, a sand filter pool, an ozone activated carbon filter pool, an ultrafiltration membrane filter pool and an automatic control system which are sequentially connected; the water inlet end of the pre-ozone treatment pool is provided with double raw water inlet pipes; and the automatic control system executes the steps of the control method described above.

[0041] Further, the automatic control system comprises: a water quality sensor, a CO2 dosing device, a coagulant dosing device and a feedback control system.

[0042] The water quality sensor is provided with a double raw water inlet pipe, a coagulation sedimentation pool inlet, a coagulation sedimentation pool outlet, an ozone activated carbon filter pool outlet and an ultrafiltration membrane filter pool outlet respectively.

[0043] The CO2 dosing device is provided with a CO2 aeration port which is in communication with the coagulation sedimentation pool, the ozone activated carbon filter pool and the ultrafiltration membrane filter pool respectively.

[0044] The coagulant dosing device is provided with a coagulant dosing port which is in communication with the coagulation sedimentation pool.

[0045] The feedback control system executes the steps of the control method described above.

[0046] Further, the feedback control system comprises: an information acquisition module, a data processing and analysis module and a feedback control module.

[0047] The information acquisition module is used for receiving water quality data information of the water quality sensor and feeding back the water quality data information to the data processing and analysis module.

[0048] The data processing and analysis module receives data information of the information acquisition module, judges the type of raw water, and calculates and corrects the aeration amount of CO2 and the coagulant addition amount.

[0049] The feedback control module comprises a CO2 dosing control submodule and a coagulant dosing control submodule.

[0050] The CO2 dosing control submodule receives data information of the data processing and analysis module, controls the opening and closing of the CO2 aeration port and the gas flow.

[0051] The coagulant dosing control submodule controls the opening and closing of the coagulant dosing port and the dosing flow of the coagulant.

[0052] Compared with the prior art, the present application has the following beneficial effects:

[0053] (1) The present application effectively improves the coagulation and sedimentation effect by fine CO2 automatic dosing control, and reduces the concentration of aluminum ions in the water body, thereby prolonging the membrane life and promoting the effective operation of the entire water purification process.

[0054] (2) Improve coagulation efficiency: By precisely controlling CO2 dosing and optimizing pH value, the coagulation efficiency of aluminum salt coagulant is significantly improved, the flocculation time is reduced, and the treatment speed is improved.

[0055] (3) Reduce coagulant dosage: Under the optimized pH condition, the use amount of aluminum salt coagulant is reduced, the operation cost is reduced, and the potential environmental impact of aluminum salt coagulant is reduced.

[0056] (4) Reduce the use of chemical additives: Using CO2 instead of traditional acidification coagulant or directly adding acid, reducing the use of chemical additives, reducing environmental pollution and operation risk.

[0057] (5) Improve water quality safety: By reducing the aluminum concentration in the finished water, the water quality safety is improved, and the more stringent drinking water standards and health requirements are met.

[0058] (6) The present application has good operation simplicity, system stability and scalability, and is suitable for water plants of different scales and easy to integrate with other water treatment processes. BRIEF DESCRIPTION OF DRAWINGS

[0059] Figure 1 is a device schematic diagram of an embodiment of the city dual water source water purification system of the present application;

[0060] Among them, 1 is a pre-ozone treatment tank, 2 is a coagulation and sedimentation tank, 3 is a sand filter tank, 4 is an ozone activated carbon filter tank, 5 is an ultrafiltration membrane filter tank, 6 is a dual raw water inlet pipe, 8. is a water outlet.

[0061] Figure 2 is a mechanism schematic diagram of an embodiment of the city dual water source water purification system of the present application;

[0062] Among them, 2 is a coagulation and sedimentation tank, 4 is an ozone activated carbon filter tank, 5 is an ultrafiltration membrane filter tank, 7 is an automatic control system, 71 is a water quality online monitoring equipment, 72 is a CO2 dosing equipment, 73 is a coagulant dosing equipment, and 74 is a feedback control system.

[0063] Figure 3 is a structure block diagram of an embodiment of the feedback control system in the city dual water source water purification system of the present application;

[0064] Wherein, 74 feedback control system, 741 information collection module, 742 data processing analysis module, 743 feedback control module.

[0065] Figure 4 It is the flow schematic diagram of the embodiment of the control method of the city double water source water purification system of the application. DETAILED DESCRIPTION

[0066] In order to make the purpose, technical scheme and advantages of the application more clear and obvious, the specific embodiments of the high pH raw water purification control system and control method are described below with reference to the drawings. It should be understood that the specific embodiments described herein are only used to explain the application and not to limit the application.

[0067] The II type raw water described in the application refers to the raw water with pH of 7.6~ 8.8, permanganate index of 2.4 ~ 4.8 mg / L, ammonia nitrogen of 0.1 ~ 0.6 mg / L and turbidity of 12 ~ 25 NTU, which is generally derived from wetland water, lake water and river water.

[0068] The I type raw water described in the application refers to the raw water with pH lower than 7.6 and turbidity lower than 12 NTU, which is treated as I type raw water for subsequent treatment according to the regulation of II type raw water.

[0069] The water treatment qualified effluent described in the application has pH of 6.5~ 7.5, permanganate index of 1.0~ 2.5 mg / L, ammonia nitrogen of 0.04 ~ 0.1 mg / L and turbidity of 0 ~ 0.2 NTU.

[0070] The application provides a city double water source water purification system, specifically as shown in the figure. Figure 1 The city double water source water purification system of the application is composed of a pre-ozone treatment pool, a coagulation sedimentation pool, a sand filter pool, an ozone activated carbon filter pool, an ultrafiltration membrane filter pool and an automatic control system connected in sequence. When water treatment is performed, water flows through the pre-ozone treatment pool, the coagulation sedimentation pool, the sand filter pool, the ozone activated carbon filter pool and the ultrafiltration membrane filter pool in sequence.

[0071] Specifically, the pre-ozone treatment pool is provided with double raw water inlet pipes at the water inlet end, and an outlet pipe is arranged at the water outlet end of the ultrafiltration membrane filter pool.

[0072] Specifically, ozone gas is added in the pre-ozone treatment pool, the ozone gas contacts with the water body, changes the properties of the suspended matter in the raw water, so that it is more easily combined with the coagulant to form larger flocculation bodies, which are more easily removed in the subsequent sedimentation and filtration process, thereby improving the coagulation effect and treatment efficiency.

[0073] Specifically, the coagulation sedimentation tank is provided with a dosing port for adding coagulant and a gas inlet for adding CO2 gas. The coagulant added in the coagulation sedimentation tank is polyaluminum chloride, which makes the impurities such as suspended solids and colloidal particles in the water coagulate into larger flocculation bodies. These flocculation bodies have larger adsorption capacity and can adsorb suspended solids, bacteria and dissolved substances in the water. Through static sedimentation, these flocculation bodies gradually settle to the bottom of the tank, thereby realizing purification of the water body.

[0074] Specifically, the sand filter tank includes two layers of sand filter layers, and the sand filter particles in the two layers of sand filter layers have different particle sizes, so as to filter the suspended solids, particles and organic matters in the water body.

[0075] Specifically, the bottom of the ozone activated carbon filter tank is provided with a water inlet, and the top is provided with a water outlet, and the water flow direction is from bottom to top. Preferably, the ozone activated carbon filter tank is sequentially provided with first to third activated carbon filter layers from bottom to top; the double aeration device of oxygen and carbon dioxide is arranged in the first activated carbon filter layer and the third activated carbon filter layer, and the oxygen aeration device is arranged at the bottom of the second activated carbon filter layer.

[0076] Specifically, for the ozone activated carbon filter tank and the ultrafiltration membrane filter tank, oxygen needs to be exposed, and the exposure method adopts a conventional method, which is not described in detail in the present application.

[0077] In the present application, the specific model and specification of the coagulation sedimentation tank, the sand filter tank, the ozone activated carbon filter tank and the aerated membrane filter tank are not strictly limited.

[0078] Specifically, in one embodiment, the water quality online monitoring device 71 is connected to the coagulation sedimentation tank 2, the sand filter tank 3, the ozone activated carbon filter tank 4 and the ultrafiltration membrane filter tank 5. Figure 2 As shown in the figure, the automatic control system 7 is composed of a water quality online monitoring device 71, a CO2 dosing device 72, a coagulant dosing device 73 and a feedback control system 74. The automatic control can adopt a PLC control system or a DCS control system.

[0079] Specifically, the water quality online monitoring device 71 is provided with water quality monitoring probes respectively installed at the water inlet of the coagulation sedimentation tank 2, the water outlet of the coagulation sedimentation tank 2, the inlet of the ozone activated carbon filter tank 4 and the inlet of the ultrafiltration membrane filter tank 5,

[0080] The water quality monitoring probe arranged at the water inlet of the coagulation sedimentation tank can detect the pH value and turbidity of the water flow, the water quality monitoring probe arranged at the inlet of the ozone activated carbon filter tank and the inlet of the aerated membrane filter tank can at least detect the pH value of the water flow, and the water quality monitoring probe arranged at the water outlet of the coagulation sedimentation tank can at least detect the turbidity of the water flow.

[0081] The CO2 adding device comprises a CO2 outlet pipe, a metering pump and a CO2 storage tank.

[0082] Specifically, in one embodiment, the feedback control system 74 comprises an information acquisition module 741, a data processing and analysis module 742 and a feedback control module 743. Figure 3 Specifically, in one embodiment, the feedback control system 74 comprises an information acquisition module 741, a data processing and analysis module 742 and a feedback control module 743.

[0083] As shown in the figure, the feedback control system 74 comprises an information acquisition module 741, a data processing and analysis module 742 and a feedback control module 743. Figure 4 As shown in the figure, the feedback control system 74 comprises an information acquisition module 741, a data processing and analysis module 742 and a feedback control module 743.

[0084] According to the pH value data of the raw water at the inlet of the coagulation sedimentation tank, it is determined whether the raw water is type I raw water or type II raw water, and the selection of the treatment mode is performed according to the type of the raw water.

[0085] The control method I for type I raw water comprises the following steps:

[0086] I-S1: obtaining a first theoretical relationship curve between the pH value and the CO2 aeration amount and a second theoretical relationship curve between the turbidity and the coagulant addition amount by taking type I raw water as a water sample.

[0087] Specifically, in the control method I, in I-S1, the first theoretical relationship curve is obtained by taking type I raw water as a water sample, preparing simulated water samples I with different pH values, introducing CO2 gas into the simulated water samples I, measuring the changes of the pH value and the CO2 aeration amount, and establishing the first theoretical relationship curve between the pH value and the CO2 aeration amount; the second theoretical relationship curve is obtained by taking type I raw water as a water sample, adding an aluminum salt coagulant to the water sample, measuring the changes of the turbidity and the coagulant addition amount, and establishing the second theoretical relationship curve between the turbidity and the coagulant addition amount.

[0088] Specifically, in the control method I, the first theoretical relationship curve and the second theoretical relationship curve need to be input into the data processing and analysis module before the system is operated.

[0089] I-S2: Real-time monitoring of pH value, turbidity of the coagulation sedimentation tank inlet, pH value of the ozone activated carbon filter tank inlet, pH value of the ultrafiltration membrane filter tank inlet, and turbidity of the coagulation sedimentation tank outlet.

[0090] I-S3: Accessing the pH value data of I-S2, obtaining the CO2 real-time aeration amount in the coagulation sedimentation tank, the ozone activated carbon filter tank and the ultrafiltration membrane filter tank according to the first theoretical relationship curve; accessing the turbidity data of I-S2, obtaining the coagulant real-time dosage in the coagulation sedimentation tank according to the second theoretical relationship curve.

[0091] Specifically, in the control method of the urban dual water source water purification system, the turbidity requirement of the final effluent is 0 ~ 0.2 NTU, therefore, in the data processing and analysis module, the turbidity of the coagulation sedimentation tank effluent is reduced to 0.1 NTU, and in actual use, the coagulant real-time dosage in the coagulation sedimentation tank is obtained according to the second theoretical relationship curve combined with the raw water turbidity.

[0092] Specifically, in the control method of the urban dual water source water purification system, in the data processing and analysis module, the pH value in the coagulation sedimentation tank is reduced to 7, and in actual use, the CO2 real-time aeration amount in the coagulation sedimentation tank is obtained according to the first theoretical relationship curve combined with the pH value of the coagulation sedimentation tank inlet.

[0093] Specifically, in the control method of the urban dual water source water purification system, in the data processing and analysis module, the pH value of the water in the ozone activated carbon filter tank is maintained at 7, and in actual use, the CO2 real-time aeration amount in the ozone activated carbon filter tank is obtained according to the first theoretical relationship curve combined with the pH value of the ozone activated carbon filter tank inlet.

[0094] Specifically, in the control method of the urban dual water source water purification system, in the data processing and analysis module, the pH value of the water in the ultrafiltration membrane filter tank is maintained at 7, and in actual use, the CO2 real-time aeration amount in the ultrafiltration membrane filter tank is obtained according to the first theoretical relationship curve combined with the pH value of the ultrafiltration membrane filter tank inlet.

[0095] I-S4: According to the CO2 real-time aeration amount and the coagulant real-time dosage obtained by I-S3, controlling the discharge amount of CO2 in the ozone activated carbon filter tank and the ultrafiltration membrane filter tank, and the discharge amount of CO2 and the dosage of coagulant in the coagulation sedimentation tank.

[0096] Specifically, the pH value of the coagulation sedimentation tank inlet, the turbidity of the coagulation sedimentation tank inlet, the pH value of the ozone activated carbon filter inlet, the pH value of the ultrafiltration membrane filter inlet, and the input to the data processing analysis module, the data processing analysis module obtains the CO2 real-time aeration amount in the coagulation sedimentation tank, the CO2 real-time aeration amount in the ozone activated carbon filter, the CO2 real-time aeration amount in the ultrafiltration membrane filter, and the coagulant real-time dosage in the coagulation sedimentation tank according to the pre-input first theoretical relationship curve, the second theoretical relationship curve, and outputs to the feedback control module, controls the CO2 dosing device, the coagulant dosing device to add CO2 and coagulant.

[0097] The raw water of type II adopts control method II, which comprises:

[0098] II-S1: setting the following data information in the automatic control system:

[0099] 1) the first deviation relationship curve between the pH value and the CO2 aeration amount;

[0100] 2) the CO2 average deviation coefficient;

[0101] 3) the second deviation relationship curve between the turbidity and the coagulant addition amount;

[0102] 4) the coagulant average deviation coefficient;

[0103] The first deviation relationship curve is obtained by taking the raw water of type II as a simulation water sample II, exposing CO2 gas to the simulation water sample II, measuring the changes of the pH value and the CO2 aeration amount, and establishing the first deviation relationship curve between the pH value and the CO2 aeration amount.

[0104] The second deviation relationship curve is obtained by taking the simulation water sample II, adding an aluminum salt coagulant to the simulation water sample II, measuring the changes of the turbidity and the coagulant addition amount, and establishing the second deviation relationship curve between the turbidity and the coagulant addition amount.

[0105] The CO2 average deviation coefficient is obtained by:

[0106] The standard water of the II-type raw water treatment is taken as a water sample, and a third theoretical relationship curve between the pH value and the CO2 aeration amount is established; the II-type raw water is taken as a water sample, and a first deviation relationship curve between the pH value and the CO2 aeration amount is established.

[0107] According to formula (1), the CO2 average deviation coefficient is calculated;

[0108] (1);

[0109] wherein, represents the average deviation coefficient of CO2; i represents the numerical value of the change of pH in the simulated water sample II, i is from high to low, the initial value of i is the initial pH value of the simulated water sample II, which is generally 7.5-9.0, and n is the minimum value after the pH value decreases, which is generally 6.0-7.0; N represents the number of times of measuring the pH value and the corresponding CO2 deviation aeration amount in the process of the pH value decreasing from i to n; represents the CO2 deviation aeration amount when the pH value is i, which is obtained through the first deviation relationship curve; represents the CO2 theoretical aeration amount when the pH value is i, which is obtained through the third theoretical relationship curve.

[0110] The method for obtaining the average deviation coefficient of the coagulant is as follows:

[0111] The fourth theoretical relationship curve between the turbidity and the coagulant addition amount is established by taking the treated water of the raw water of type II as the water sample, and the fifth theoretical relationship curve between the Al 3+ concentration and the coagulant addition amount is established; the second deviation relationship curve between the turbidity and the coagulant addition amount is established by taking the raw water of type II as the water sample;

[0112] According to formula (2), the average deviation coefficient of the coagulant is calculated;

[0113] (2);

[0114] wherein, represents the average deviation coefficient of the coagulant; j represents the numerical value of the change of turbidity in the simulated water sample II, j is from high to low, the initial value of j is the initial turbidity value of the simulated water sample II, which is generally 20.0-25.0, and m is the minimum value after the turbidity decreases, which is generally 0-1.0; M represents the number of times of measuring the turbidity and the corresponding coagulant addition amount in the process of the turbidity decreasing from j to m; the coagulant deviation addition amount D dj represents the coagulant deviation addition amount when the turbidity is j in the second deviation relationship curve; D tj represents the coagulant theoretical addition amount when the turbidity is j.

[0115] II-S2: Real-time monitoring of the pH value at the inlet of the coagulation sedimentation tank, the pH value at the inlet of the ozone activated carbon filter tank, the pH value at the inlet of the membrane filtration tank, and the turbidity at the outlet of the coagulation sedimentation tank.

[0116] The pH value and the turbidity data in II-S2 are obtained in the same way as in I-S2.

[0117] II-S3: the pH value data of II-S2 is substituted into the first deviation relationship curve to obtain the real-time deviation aeration amount of CO2 in the coagulation sedimentation tank, the ozone activated carbon filter tank and the ultrafiltration membrane filter tank, and then the real-time correction aeration amount of CO2 is obtained according to the average deviation coefficient of CO2;

[0118] The turbidity data of II-S2 is substituted into the second deviation relationship curve to obtain the real-time deviation addition amount of coagulant, and then the real-time correction addition amount of coagulant in the coagulation sedimentation tank is calculated according to the average deviation coefficient of coagulant set inside;

[0119] II-S4: according to the real-time correction aeration amount of CO2 and the real-time correction addition amount of coagulant obtained in II-S3, the discharge amount of CO2 in the ozone activated carbon filter tank and the ultrafiltration membrane filter tank, and the discharge amount of CO2 and the addition amount of coagulant in the coagulation sedimentation tank are controlled.

[0120] Specifically, in II-S4, the calculation formula of the real-time correction aeration amount of CO2 is: real-time correction aeration amount of CO2 = real-time deviation aeration amount of CO2 × average deviation coefficient of CO2; and the calculation formula of the real-time correction addition amount of coagulant is: real-time correction addition amount of coagulant = real-time deviation addition amount of coagulant × average deviation coefficient of coagulant.

[0121] Specifically, the pH value of the coagulation sedimentation tank inlet, the turbidity of the coagulation sedimentation tank inlet, the pH value of the ozone activated carbon filter tank inlet, the pH value of the ultrafiltration membrane filter tank inlet and the turbidity of the coagulation sedimentation tank outlet obtained from II-S2 are input into the data processing and analysis module, the data processing and analysis module obtains the real-time aeration amount of CO2 in the coagulation sedimentation tank, the real-time aeration amount of CO2 in the ozone activated carbon filter tank, the real-time aeration amount of CO2 in the ultrafiltration membrane filter tank, and the real-time addition amount of coagulant in the coagulation sedimentation tank according to the pre-input first deviation relationship curve and the second deviation relationship curve, and outputs to the feedback control module to control the CO2 and coagulant addition devices to add CO2 and coagulant.

[0122] During the treatment of raw water controlled by the control method I or the control method II, the Al 3+ concentration of the ozone activated carbon filter tank outlet is monitored in real time, and if the Al 3+ concentration is 0.05-0.2 mg / L, the effluent of the aeration ozone activated carbon filter tank is reflowed to the coagulation sedimentation tank.

[0123] For example, the application provides an application case. For a certain water plant in a city, the water purification system of the application is used for water purification treatment, and the raw water of the water plant comes from the urban wetland water, and the water quality is: pH is 7.7-8.2; permanganate index is 2.7-3.5 mg / L; ammonia nitrogen is 0.1-0.4 mg / L; turbidity is 12.3-16.9 NTU. Through the water purification system and the matching control method thereof, the CO2 aeration amount can be reduced from 12 mg / L to 8 mg / L, the coagulant consumption is reduced by 25%-35%, and the final water purification efficiency can be improved by 15%-20%; the effluent water quality is: pH is 6.8-7.5; permanganate index is 1.3-1.7 mg / L; ammonia nitrogen is 0.04-0.08 mg / L; turbidity is 0-0.11 NTU.

[0124] The specific embodiments described above illustrate the technical solutions and beneficial effects of the application. It should be understood that the above description is only the most preferred embodiment of the application and is not intended to limit the application. Any modification, supplement and equivalent replacement within the principle range of the application should be included in the protection scope of the application.

Claims

1. A control method of a municipal dual water source water purification system, characterized by, The urban dual water source purification system comprises a pre-ozone treatment pool, a coagulation sedimentation pool, a sand filter pool, an ozone activated carbon filter pool, an ultrafiltration membrane filter pool and an automatic control system connected in sequence; a double raw water inlet pipe is arranged at the water inlet end of the pre-ozone treatment pool; The control method comprises: According to the pH value data of the raw water at the inlet of the coagulation sedimentation pool, it is determined whether the raw water is type I raw water or type II raw water; The pH value of the type I raw water is lower than 7.6, and the turbidity is lower than 12 NTU; the pH value of the type II raw water is 7.6-8.8, and the turbidity is 12-25 NTU; The type I raw water adopts control method I, which comprises: I-S1: taking the type I raw water as a water sample, a first theoretical relationship curve between the pH value and the CO2 aeration amount, and a second theoretical relationship curve between the turbidity and the coagulant addition amount are obtained; I-S2: the pH value at the inlet of the coagulation sedimentation pool, the pH value at the inlet of the ozone activated carbon filter pool, the pH value at the inlet of the ultrafiltration membrane filter pool, and the turbidity at the outlet of the coagulation sedimentation pool are monitored in real time; I-S3: the pH value data of I-S2 is retrieved, the CO2 real-time aeration amount in the coagulation sedimentation pool, the ozone activated carbon filter pool and the ultrafiltration membrane filter pool is obtained according to the first theoretical relationship curve, the turbidity data of I-S2 is retrieved, and the coagulant real-time addition amount in the coagulation sedimentation pool is obtained according to the second theoretical relationship curve; I-S4: according to the CO2 real-time aeration amount and the coagulant real-time addition amount obtained in I-S3, the discharge amount of CO2 in the ozone activated carbon filter pool and the ultrafiltration membrane filter pool, and the discharge amount of CO2 and the addition amount of coagulant in the coagulation sedimentation pool are controlled; The type II raw water adopts control method II, which comprises: II-S1: the following data information is obtained: 1) taking the type II raw water as a water sample, a first deviation relationship curve between the pH value and the CO2 aeration amount is obtained; 2) a CO2 average deviation coefficient; 3) taking the type II raw water as a water sample, a second deviation relationship curve between the turbidity and the coagulant addition amount is obtained; 4) a coagulant average deviation coefficient; II-S2: the pH value at the inlet of the coagulation sedimentation pool, the pH value at the inlet of the ozone activated carbon filter pool, the pH value at the inlet of the ultrafiltration membrane filter pool, and the turbidity at the outlet of the coagulation sedimentation pool are monitored in real time; II-S3: the pH value data of II-S2 is substituted into the first deviation relationship curve, the CO2 real-time deviation aeration amount in the coagulation sedimentation pool, the ozone activated carbon filter pool and the ultrafiltration membrane filter pool is obtained, and the CO2 real-time correction aeration amount is obtained according to the CO2 average deviation coefficient; the turbidity data of II-S2 is substituted into the second deviation relationship curve, the coagulant real-time deviation addition amount is obtained, and the coagulant real-time correction addition amount in the coagulation sedimentation pool is calculated according to the coagulant average deviation coefficient; II-S4: according to the CO2 real-time correction aeration amount and the coagulant real-time correction addition amount obtained in II-S3, the discharge amount of CO2 in the ozone activated carbon filter pool and the ultrafiltration membrane filter pool, and the discharge amount of CO2 and the addition amount of coagulant in the coagulation sedimentation pool are controlled.

2. The control method of the urban dual water source water purification system according to claim 1, characterized in that, In I-S1, the first theoretical relationship curve is obtained by using I-type raw water as a water sample, preparing simulated water samples I with different pH values, exposing CO2 gas into the simulated water samples I, measuring the changes of pH value and CO2 exposure amount, and establishing the first theoretical relationship curve between the pH value and the CO2 exposure amount. The second theoretical relationship curve is obtained by using I-type raw water as a water sample, adding aluminum salt coagulant into the water sample, measuring the changes of turbidity and coagulant addition amount, and establishing the second theoretical relationship curve between the turbidity and the coagulant addition amount.

3. The control method of the urban dual water source water purification system according to claim 1, characterized in that, In II-S1, the first deviation relationship curve is obtained by using II-type raw water as a water sample, exposing CO2 gas into the water sample, measuring the changes of pH value and CO2 exposure amount, and establishing the first deviation relationship curve between the pH value and the CO2 exposure amount. The second deviation relationship curve is obtained by using II-type raw water as a water sample, adding aluminum salt coagulant into the water sample, measuring the changes of turbidity and coagulant addition amount, and establishing the second deviation relationship curve between the turbidity and the coagulant addition amount.

4. The control method of the urban dual water source water purification system according to claim 1, characterized in that, In II-S1, the CO2 average deviation coefficient is obtained by: using the II-type raw water treated by water purification to obtain standard effluent as a water sample, establishing a third theoretical relationship curve between the pH value and the CO2 exposure amount, and using II-type raw water as a water sample, establishing a first deviation relationship curve between the pH value and the CO2 exposure amount; calculating the CO2 average deviation coefficient according to formula (1); （1）； wherein, represents the average deviation coefficient of CO2; i represents the numerical value of the change of pH in the simulated water sample II, i is from high to low, the initial value of i is the initial pH value of the simulated water sample II, generally 7.5~9.0, n is the lowest value after the pH value decreases, generally 6.0~7.0; N represents the number of times of measuring the pH and the corresponding CO2 deviation aeration amount in the process of the pH decreasing from i to n; represents the CO2 deviation aeration amount when the pH is i, which is obtained through the first deviation relationship curve; represents the CO2 theoretical aeration amount when the pH is i, which is obtained through the third theoretical relationship curve.

5. The control method of the urban dual water source water purification system according to claim 1, characterized in that, In II-S1, the coagulant average deviation coefficient is obtained by: using the II-type raw water treated by water purification to obtain standard effluent as a water sample, establishing a fourth theoretical relationship curve between the turbidity and the coagulant addition amount, and using II-type raw water as a water sample, establishing a second deviation relationship curve between the turbidity and the coagulant addition amount; calculating the coagulant average deviation coefficient according to formula (2); （2）； wherein, represents the average deviation coefficient of coagulant; j represents the value of turbidity change in simulated water sample II, j is from high to low, the initial value of j is the initial turbidity value of simulated water sample II, generally 20.0 ~ 25.0, m is the minimum value after turbidity decreases, generally 0 ~ 1.0; M represents the number of times of measuring turbidity and corresponding coagulant dosage in the process of turbidity decreasing from j to m; coagulant deviation dosage D dj represents the coagulant deviation dosage when the turbidity is j in the second deviation relationship curve; D tj represents the coagulant theoretical dosage when the turbidity is j.

6. The control method of the urban dual water source water purification system according to claim 1, characterized in that, In II-S4, the calculation formula of the CO2 real-time correction exposure amount is: CO2 real-time correction exposure amount=CO2 real-time deviation exposure amount×CO2 average deviation coefficient; The calculation formula of the coagulant real-time correction addition amount is: coagulant real-time correction addition amount=coagulant real-time deviation addition amount×coagulant average deviation coefficient.

7. A city dual water source purifying system, characterized in that, It comprises: It comprises a pre-ozone treatment pool, a coagulation and sedimentation pool, a sand filter pool, an ozone activated carbon filter pool, an ultrafiltration membrane filter pool, and an automatic control system connected in sequence; The water inlet end of the pre-ozone treatment pool is provided with double raw water inlet pipes; the automatic control system performs the steps of the control method according to any one of claims 1-6.

8. The urban dual water source purification system of claim 7, wherein, The automatic control system comprises a water quality sensor, a CO2 dosing device, a coagulant dosing device, and a feedback control system; The water quality sensor is provided with double raw water inlet pipes, coagulation and sedimentation pool inlets, coagulation and sedimentation pool outlets, ozone activated carbon filter pool outlets, and ultrafiltration membrane filter pool outlets; The CO2 dosing device is provided with CO2 exposure ports communicated with the coagulation and sedimentation pool, the ozone activated carbon filter pool, and the ultrafiltration membrane filter pool; The coagulant dosing device is provided with a coagulant dosing port communicated with the coagulation and sedimentation pool; The feedback control system performs the steps of the control method according to any one of claims 1-6.

9. The urban dual water source purification system of claim 8, wherein, The feedback control system comprises an information collection module, a data processing and analysis module and a feedback control module; The information collection module is used for receiving water quality data information of a water quality sensor and feeding back the water quality data information to the data processing and analysis module; The data processing and analysis module receives data information of the information collection module, judges raw water types, and calculates and corrects CO2 aeration quantity and coagulant addition quantity; The feedback control module comprises a CO2 addition control submodule and a coagulant addition control submodule; The CO2 addition control submodule receives data information of the data processing and analysis module, controls opening and closing of a CO2 aeration port and gas flow; The coagulant addition control submodule controls opening and closing of a coagulant addition port and coagulant addition flow.

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