Chemical dosing system for pre-chlorination enhanced coagulation algae removal and refined intelligent regulation and control method

Abstract

The invention discloses a dosing system for removing algae through pre-chlorination enhanced coagulation and a refined intelligent regulation and control method, and belongs to the technical field of water treatment. The system comprises a raw water pump, a tubular static mixer, a flocculation basin, a sedimentation basin, an industrial personal computer and multiple online detectors, and is used for monitoring flow, temperature, turbidity, characteristic fluorescence peak intensity, ultraviolet absorbance and organic matter concentration. On the basis of integrated real-time sensing data, by monitoring the characteristic fluorescence intensity ratio of algae cells after pre-chlorination and before flocculation, the dosage of an oxidizing agent (available chlorine) and a coagulant is finely and intelligently regulated and controlled on the premise of ensuring the integrity of the algae cells and enhancing coagulation. Under different water quality conditions, the system shows good self-adaptive capacity, accurate adding of an oxidizing agent (available chlorine) and a coagulant is achieved by applying a dynamic adjustment algorithm, the effluent quality is guaranteed, and the medicine consumption is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of water treatment, and discloses a dosing system and a refined intelligent control method suitable for pre-chlorination enhanced coagulation and algae removal of water source water, and particularly relates to the technical field of pre-oxidation enhanced coagulation and algae removal water treatment. Background Art

[0002] The problem of algal blooms has become an increasingly prominent ecological and environmental safety issue in lakes and rivers around the world, posing a serious threat to drinking water safety and the sustainability of aquatic ecosystems. During algal blooms, algal pollutants in source water have a serious impact on water quality and water treatment processes. In the water treatment process, the traditional coagulation-sedimentation process is still the main means to remove algal cells and algal pollutants. However, due to the low specific density, high motility, morphological diversity and surface negative charge of algal cells, algal cells are difficult to be effectively removed in the coagulation-sedimentation treatment unit, resulting in an increase in the dosage of coagulants, increased reagent costs and possible secondary pollution of metal ion residues. In addition, algal cells will also aggravate the scaling of subsequent filtration units, shorten the filter cycle, and increase the frequency of backwashing. Therefore, in response to the problem of algal blooms, the traditional coagulation-sedimentation-sand filtration water treatment process can no longer meet the needs, and enhanced technologies for conventional water treatment processes should be developed to improve the removal effect of algae and ensure the safety of drinking water quality.

[0003] The enhanced algae removal technologies in drinking water treatment plants mainly include enhanced coagulation, pre-oxidation, flotation, electrochemical method and ultrasound. Considering the decontamination efficiency, operating cost, operating environment and engineering feasibility, chemical pre-oxidation is a widely used method in the enhanced conventional treatment process in drinking water treatment plants. It mainly changes the surface characteristics and Zeta potential of algae cells and destroys the organic coating to inactivate algae cells, so as to achieve the effect of enhanced subsequent coagulation and algae removal. Chlorine-based oxidants (including liquid chlorine, sodium hypochlorite, chlorine dioxide and bleaching powder) have become widely used oxidants in water plants due to their low cost and high efficiency. However, no matter what kind of oxidant is used, when the oxidant dosage is too high, it will lead to the lysis of algae cells and the release of intracellular organic matter (IOM). The low molecular weight and hydrophilic components in IOM are not only difficult to be removed by coagulation, but also easy to form complexes with coagulants to increase the dosage of coagulants. Therefore, moderate pre-oxidation technology that maintains cell integrity and prevents the release of IOM is crucial for the treatment of high algae water. Moderate pre-oxidation desorbs S-AOM (attached organic matter) on the surface of algae cells, destabilizes and inactivates the algae cells without destroying their integrity, thereby achieving the purpose of enhanced coagulation and algae removal.

[0004] In order to solve the shortcomings of traditional algal cell integrity evaluation methods (such as scanning electron microscopy, fluorescence microscopy and flow cytometry), such as complex pretreatment, long analysis time, limited staining conditions, and inability to monitor in real time in water plants, the applicant has developed a dosing system based on the identification of algae characteristic fluorescent substances and a refined intelligent control method. This method can not only realize real-time online monitoring of algal cell integrity in water plants, but also determine the upper limit of oxidant dosage according to changes in raw water quality. In order to further improve the refined dosing control of oxidants and coagulants, it is urgent to develop an intelligent dosing system for pre-oxidation enhanced coagulation and algae removal to ensure effluent water quality and realize refined dosing of agents. The system will combine real-time sensing technology with data analysis to achieve precise dosing of oxidants and coagulants through intelligent control. Under moderate pre-oxidation conditions, the system can further optimize the pre-oxidation-coagulation treatment process to effectively respond to the increasingly severe challenges of algae-containing water source treatment. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a dosing system and refined intelligent control method for pre-chlorination and enhanced coagulation of source water to remove algae. The system can not only achieve moderate pre-oxidation by identifying the structural integrity of algae cells, but also finely control the dosage of oxidants and coagulants based on the changes in raw water quality conditions, thereby ensuring the quality of drinking water supply and achieving refined dosing of agents.

[0006] The technical solution adopted by the system of the present invention is: a dosing system for pre-chlorination, enhanced coagulation and algae removal of water source water, characterized in that:

[0007] It includes a raw water pump (1), a tubular static mixer (2), a flocculation tank (3), a sedimentation tank (4), a flow meter (5), an online temperature detector (6), an online turbidity detector ① (7), an online ultraviolet detector ① (8), an online organic matter analyzer ① (9), an oxidant tank (10), a metering pump ① (11), a metering pump ② (12), a coagulant tank (13), an online fluorescence detector (14), an online turbidity detector ② (15), an online ultraviolet detector ② (16), an online organic matter analyzer ② (17), a variable frequency speed controller ① (18), a variable frequency speed controller ② (19), and an industrial computer (20);

[0008] The raw water pump (1), the tubular static mixer (2), the flocculation tank (3), and the sedimentation tank (4) are sequentially connected in series by pipelines, and source water is sent into the tubular static mixer (2) through the raw water pump (1);

[0009] The flow meter (5), online temperature detector (6), online turbidity detector ① (7), online ultraviolet detector ① (8), and online organic matter analyzer ① (9) are arranged on the raw water inlet pipe, and the online fluorescence detector (14) is arranged on the flocculation tank (3) inlet pipe; the online turbidity detector ② (15), online ultraviolet detector ② (16), and online organic matter analyzer ② (17) are arranged on the sedimentation tank outlet pipe.

[0010] The oxidant tank (10) is connected to the tubular static mixer (2) via a metering pump ① (11) to add the oxidant into the tubular static mixer (2). The oxidant may be a chlorine-based oxidant such as liquid chlorine, sodium hypochlorite, and bleaching powder; the coagulant tank (13) is connected to the tubular static mixer (2) via a metering pump ② (12) to add the coagulant into the tubular static mixer (2). The coagulant may be an aluminum salt coagulant (polyaluminum chloride, aluminum sulfate, polyaluminum sulfate, etc.) or an iron salt coagulant (ferric chloride, ferrous sulfate, ferric sulfate, etc.);

[0011] The variable frequency speed controller ① (18) is electrically connected to the metering pump ① (11) for controlling the dosage of the oxidant; the variable frequency speed controller ② (19) is electrically connected to the metering ② (12) for controlling the dosage of the coagulant; the industrial computer (20) is electrically connected to the flow meter (5), the online temperature detector (6), the online turbidity detector ① (7), the online ultraviolet detector ① (8), the online organic matter analyzer ① (9), the online fluorescence detector (14), the online turbidity detector ② (15), the online ultraviolet detector ② (16), the online organic matter analyzer ② (17), the variable frequency speed controller ① (18) and the variable frequency speed controller ② (19), respectively.

[0012] The flow meter (5) monitors the raw water flow in real time, the online temperature detector (6) monitors the raw water temperature in real time, and is particularly used to monitor the risk of algae outbreaks, the online turbidity detector ① (7) monitors the raw water turbidity in real time, and the online ultraviolet detector ① (8) monitors the raw water ultraviolet absorbance (UV 254 ), the online organic matter analyzer ① (9) monitors the concentration of dissolved organic carbon (DOC) in the raw water in real time, and the online fluorescence detector (14) simultaneously detects the characteristic fluorescent substances released after the algae cell membrane is damaged and the characteristic peak fluorescence intensity of humus-like substances related to natural organic matter. The above-mentioned collected data are transmitted to the industrial computer (20), the online turbidity detector ② (15) monitors the turbidity of the precipitated water in real time, and the online ultraviolet detector ② (16) monitors the ultraviolet absorbance (UV 254 ), the online organic matter analyzer②(17) monitors the concentration of dissolved organic carbon (DOC) in the precipitated water in real time, and the industrial control computer (20) automatically adjusts the dosage of the reagent according to a preset algorithm.

[0013] The flocculation tank (3) can be a mechanical reaction flocculation tank or a hydraulic reaction flocculation tank, such as a baffle reaction flocculation tank, a perforated plate reaction flocculation tank, a corrugated plate reaction flocculation tank, etc. The hydraulic retention time of the flocculation tank is 15 to 20 minutes, and the average velocity gradient is controlled at 20 to 50 seconds. -1 ; The sedimentation tank (4) can be an inclined plate sedimentation tank, an inclined tube sedimentation tank or a horizontal flow sedimentation tank.

[0014] The technical solution adopted by the method of the present invention is: a refined intelligent control method for a dosing system for pre-chlorination enhanced coagulation algae removal, characterized in that:

[0015] It aims to integrate multiple online detection instruments to monitor key water quality parameters in real time, and dynamically adjust the dosage of oxidants and coagulants in combination with intelligent algorithms to achieve precise control of the pre-chlorination and coagulation processes, thereby achieving the purpose of efficiently removing algae and organic pollutants.

[0016] This method is applicable to algae density of 10 3 Up to 10 6 The dominant algae species in the water source water may be blue algae, green algae and diatoms, etc. When the water temperature is between 20℃ and 30℃, the reproduction rate of algae will be significantly accelerated. Through the monitoring data of the temperature detector, the possibility of algae outbreak can be predicted in time, and the dosing strategy of secondary oxidants and coagulants can be adjusted.

[0017] The intelligent control method of the present invention is applicable to UV 254 ≤0.1cm - 1. Raw water conditions with DOC≤2.5mg / L and turbidity<40NTU are monitored in real time by online UV detector, online organic matter analyzer and online turbidity detector and integrated into the industrial computer system.

[0018] Through real-time data feedback and intelligent algorithm integration, intelligent control of the dosage of oxidant (chlorine) and coagulant (aluminum salt, iron salt) can be achieved respectively;

[0019] (1) Determine the upper limit of the oxidant (chlorine) concentration and the corresponding chlorine concentration during actual operation: Based on the data feedback from the online temperature detector, especially when the water temperature is between 20°C and 30°C, the system determines that algae may explode and the pre-oxidant needs to be regulated; the amount of chlorine added is dynamically adjusted according to the change of the fluorescence intensity ratio C1 / C2. The fluorescence intensity of C1 and C2 is detected online by an online fluorescence detector. C1 is a characteristic fluorescent substance released after the algae cell membrane is damaged (this is detected by the online fluorescence detector (14)), and C2 represents humus-like substances related to natural organic matter (also detected by the online fluorescence detector (14)).

[0020] The oxidant (chlorine) is first added using a time series model that is segmented by time, and the time points or time sequences of the addition are recorded as i=0, 1, 2, 3...n (n≥3), and the specific value of n can be designed as needed;

[0021] The concentration of the oxidant (chlorine) added at the above n time points or moments (the concentration added to the pipeline) meets the following restrictions: the chlorine concentration variation range meets 0.2mg / L≤|m i+1 -m i |≤0.5mg / L, and 0.3mg / L≤m i ≤3.0mg / L; preferably the concentration of oxidant (chlorine) increases gradually;

[0022] Chlorine dosing adopts a time series model with segmented time periods, and the raw water flow Q is calculated based on the dosing time point or time i. i and the chlorine concentration in the pipeline m i Design, dynamically adjust the speed of the oxidant metering pump to adjust the chlorine dosing pump flow rate q at time i i ,q i is the volume flow rate of the dosing (usually in L / h or m 3 / h), the calculation formula is shown in (1); Q i is the raw water flow rate at time i (in m 3 / h);m i is the chlorine concentration in the pipeline at time i (expressed in mg / L); ρ0 is the effective concentration of the oxidant in the oxidant tank (expressed in g / L or kg / m 3 express).

[0023]

[0024] In the time series i = 0, 1, 2, 3...n (n ≥ 3), the corresponding chlorine concentration at each moment is m i , the raw water flow is Q i , the corresponding chlorine dosing pump flow is q i ;

[0025] The change rate of the fluorescence intensity ratio C1 / C2 is calculated as shown in formula (2):

[0026]

[0027] (C1 / C2) i represents the fluorescence intensity ratio C1 / C2 at time i; when the k value of formula (2) reaches the maximum at time i and C1 i+1 >C1 i When the upper limit concentration of chlorine is m i The actual later stable operation is based on the chlorine concentration m at time i-1. i-1 , the actual adjustment dosing pump flow is qi-1 ; When the k value of formula (2) reaches the maximum at time i and C1 i+1 <C1 i When the upper limit concentration of chlorine is m i+2 , the corresponding chlorine concentration m in the later actual operation i+1 , the actual adjustment dosing pump flow is q i+1 ;

[0028] (2) After determining the chlorine concentration corresponding to the actual operation in step (1), the amount of coagulant added is finely regulated and determined: based on the dissolved organic carbon (DOC) and ultraviolet absorbance (UV 254 ) and turbidity removal efficiency to dynamically adjust the coagulant dosage; when the raw water UV 254 ≤0.1cm-1, DOC≤2.5mg / L, turbidity<40NTU, the dosage of coagulant should meet the requirement that the DOC removal rate of the effluent after sedimentation reaches or exceeds 20% (i.e. the ratio of effluent DOC to influent DOC≤80%), and the UV 254 The removal rate should reach or exceed 35% (i.e. the effluent UV 254 UV 254 The ratio is ≤65%), the turbidity removal rate of the effluent water after sedimentation should reach or exceed 95% (that is, the ratio of the effluent turbidity to the inlet turbidity is ≤5%), and the dosage of the coagulant is controlled in the range of 0.04 to 0.15 mM (in terms of Al or Fe).

[0029] After completing the time sequence of optimizing the dosage of oxidant (chlorine), the system automatically enters the next time sequence j=0, 1, 2, 3...n (n≥1), and the specific value of n can be set as needed; and the coagulant is added at different times j;

[0030] According to the raw water flow Q j The coagulant metering pump speed is adjusted according to the coagulant dosage to adjust the coagulant dosing pump flow rate q at different times j , calculated by formula (3). j is the raw water flow at different times (in m 3 / h);m j is the concentration of coagulant in the pipeline at different times (expressed in mM, in Al or Fe, the concentration added to the pipeline); w0 is the mass fraction of Al or Fe in the coagulant (expressed in %), ρ0 is the effective concentration of the coagulant in the coagulant tank (expressed in g / L or kg / m 3 express).

[0031]

[0032] Start the optimization of coagulant dosage. The corresponding coagulant concentration at each moment is m j, the raw water flow is Q j , the corresponding coagulant dosing pump flow is q j ; At different times, the effluent water quality meets the target requirements, DOC 出水j / DOC 进水j ≤80%,UV 254出水j / With UV 254进水j ≤65%, T 出水j / T 进水j ≤5%, the system automatically optimizes the coagulant concentration to m at time j j , and adjust the dosing pump flow rate to the corresponding q j , in order to achieve the optimal dosage of coagulant;

[0033] (3) Under the conditions corresponding to steps (1) and (2) for maintaining the raw water quality, perform the actual operation according to the corresponding chlorine concentration determined in step (1) and the amount of coagulant determined in step (2);

[0034] (4) Time series trigger mechanism based on raw water quality fluctuations: When the system monitors the raw water quality changes in real time and compares it with the raw water quality at time i=0 in step (1), if it is found that the change amplitude of any of the following indicators exceeds the preset threshold, then steps (1) to (3) are repeated to automatically start the next time series and re-optimize the chlorine and coagulant addition strategy: turbidity change exceeds 3NTU, DOC change exceeds 0.2mg / L, UV 254 Changes greater than 0.005 cm - 1

[0035] (5) By designing and implementing the automatic control method based on the fluorescence intensity ratio and water quality parameters of the above steps (1) to (4), it is embedded into the industrial computer system for centralized control. The system logic control diagram is shown in FIG. Figure 2 The system collects water quality information in real time and accurately adjusts the dosage of oxidant (chlorine) and coagulant based on the above intelligent control method.

[0036] The system can not only significantly improve the accuracy and efficiency of water treatment, but also make adaptive adjustments according to the instantaneous changes in water quality, thereby optimizing the dosage of reagents, reducing the amount of chemical reagents used, and reducing treatment costs. 3 Up to 10 6 cells / mL, UV 254 Under the raw water conditions of ≤0.1cm-1, DOC≤2.5mg / L, and turbidity<40NTU, it can achieve efficient removal of algae and organic matter, ensuring the stability and efficiency of the water treatment process.

[0037] The beneficial effects of the present invention are:

[0038] The refined intelligent dosing system of the present invention adopts a dynamic control algorithm based on the characteristic fluorescence peak intensity ratio, and integrates multi-parameter sensors such as online water temperature, turbidity, ultraviolet and organic matter analysis. Through real-time data feedback combined with intelligent algorithms, it can finely control the dosage of oxidants (chlorine) and coagulants (such as aluminum salts and iron salts) under the premise of ensuring moderate pre-oxidation, greatly reducing the amount of reagents used and reducing the cost of chemical reagents. At the same time, it improves the removal efficiency of algae and organic matter, and ensures the stability and safety of the effluent water quality. In addition, the intelligent control system has good adaptive capabilities, can quickly respond to instantaneous changes in water quality, and optimize dosing strategies. This feature makes the water treatment process more efficient and energy-saving, ensuring that the water treatment plant can operate stably and efficiently during the algae outbreak period. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic diagram of the process flow and control system of the invention.

[0040] 1-raw water pump; 2-tubular static mixer; 3-flocculation tank; 4-sedimentation tank; 5-flow meter; 6-online temperature detector; 7-online turbidity detector ①; 8-online UV detector ①; 9-online organic matter analyzer ①; 10-oxidant medicine tank; 11-metering pump ①; 12-metering pump ②; 13-coagulant medicine tank; 14-online fluorescence detector; 15-online turbidity detector ②; 16-online UV detector ②17-online organic matter analyzer ②; 18-variable frequency speed controller; 19-variable frequency speed controller ②; 20-industrial computer

[0041] Figure 2 It is the logic control diagram of the control system of the invention. DETAILED DESCRIPTION

[0042] The pre-chlorination enhanced coagulation algae removal system and refined intelligent control method of the present invention were respectively applied to the source water of three different water plants, and finally the control of algae cell integrity and the improvement of water quality after sedimentation were used to illustrate the innovation and superiority of the system and method. The present invention is described in detail by the following examples, which are only part of the examples of the present invention, not all of them.

[0043] Embodiment 1:

[0044] The algae density in the water source of water plant A is 4.0×10 4 cells / mL, cyanobacteria, green algae and diatoms are the dominant algae species, the water temperature is 25±1℃, the turbidity is 12±1NTU, the pH is 7.8±0.2, the DOC is 2.0±0.2mg / L, and the UV 254 0.087±0.005cm -1During the pre-chlorination treatment, a chlorine addition time sequence (i = 0, 1, 2, 3 ... 7 (n = 7)) is set, and the chlorine addition amount at each moment is m i , respectively 0, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 mg / L. The change of chlorine dosage at adjacent moments of the control system satisfies 0.2≤|m i+1 -m i |≤0.5, and the chlorine dosage does not exceed 3.0mg / L. The chlorine dosage is regulated according to the change of the fluorescence intensity ratio C1 / C2 k value. Through online data analysis, it reaches the maximum when the k value is 0.236, at which time the i+2th moment is 6, and the fluorescence intensity C15>C14(C1 i+1 >C1 i ), so the upper limit of chlorine dosage is m4, i.e. 1.5mg / L. Adjust the chlorine dosage to m3, i.e. 1.2mg / L. According to the preset algorithm conditions, the dosage of coagulant must meet the requirement that the DOC removal rate of the effluent after sedimentation should reach or exceed 20% (i.e. the ratio of effluent DOC to influent DOC ≤80%), and the UV of the effluent after sedimentation should reach or exceed 20%. 254 The removal rate should reach or exceed 35% (i.e. the effluent UV 254 UV 254 The ratio is ≤65%), the turbidity removal rate of the effluent water after sedimentation should reach or exceed 95% (i.e. the ratio of effluent turbidity to inlet turbidity is ≤5%), and the dosage of coagulant is controlled within the range of 0.04 to 0.15mM (in terms of Al or Fe). Through the adaptive adjustment of the system, the intelligent system adjusts the dosage of coagulant to 0.09mM (in terms of Al). At this time, the turbidity removal rate of the effluent water reached 95.7%, the DOC removal rate was 22.6%, and the UV 254 The removal rate reached 35.5%. Compared with the traditional coagulation treatment process, the turbidity removal rate increased by 13.5 percentage points, the DOC removal rate increased by 6.5 percentage points, and the UV 254 The removal rate increased by 8.9 percentage points, and the dosage of coagulant was saved by 50%. Water Plant A simultaneously achieved the goal of moderate pre-oxidation to enhance coagulation and save on chemical consumption.

[0045] Implementation Example 2:

[0046] The algae density in the water source of water plant B is 3×10 3 cells / mL, cyanobacteria and diatoms were the dominant algae species, the water temperature was 22±2℃, the turbidity was 5.0±0.5NTU, the pH was 7.5±0.1, the DOC was 1.4±0.1mg / L, and the UV 254 0.035±0.005cm -1During the pre-chlorination treatment, a chlorine addition time sequence (i = 1, 2, 3 ... 7 (n = 7)) is set, and the corresponding chlorine addition amount at each moment is m i , respectively 0, 0.3, 0.6, 0.9, 1.2, 1.5 and 1.8 mg / L. The change of chlorine dosage between adjacent moments of the control system satisfies 0.2≤|m i+1 -m i |≤0.5, and the chlorine dosage does not exceed 3.0mg / L. The chlorine dosage is regulated according to the change of the fluorescence intensity ratio C1 / C2 k value. Through online data analysis, it reaches the maximum when the k value is 0.377. At this time, the i+2th moment is 6, and the fluorescence intensity C15>C14(C1 i+1 >C1 i ), so the upper limit of chlorine dosage is m4, i.e. 0.9mg / L. Adjust the chlorine dosage to m3, i.e. 0.6mg / L. According to the preset algorithm conditions, the dosage of coagulant must meet the requirement that the DOC removal rate of the effluent after sedimentation should reach or exceed 20% (i.e. the ratio of effluent DOC to influent DOC ≤80%), and the UV of the effluent after sedimentation should reach or exceed 20%. 254 The removal rate should reach or exceed 35% (i.e. the effluent UV 254 UV 254 The ratio is ≤65%), the turbidity removal rate of the effluent water after sedimentation should reach or exceed 95% (i.e. the ratio of effluent turbidity to inlet turbidity is ≤5%), and the dosage of coagulant is controlled within the range of 0.04 to 0.15mM (in terms of Al or Fe). Through the adaptive adjustment of the system, the intelligent system adjusts the dosage of coagulant to 0.06mM (in terms of Al). At this time, the turbidity removal rate of the effluent water reached 97.3%, the DOC removal rate was 22.7%, and the UV 254 The removal rate reached 39.1%. Compared with the traditional coagulation treatment process, the turbidity removal rate increased by 11.3 percentage points, the DOC removal rate increased by 7.9 percentage points, and the UV 254 The removal rate increased by 10.9 percentage points, and the dosage of coagulant was saved by 44%. Water Plant B also achieved the goal of moderate pre-oxidation to enhance coagulation and save chemical consumption.

[0047] Implementation Example 3:

[0048] The algae density in the water source of water plant C is 1.5×10 4 cells / mL, diatoms were the dominant algae, water temperature was 20±2℃, turbidity was 12.0±0.5NTU, pH was 7.2±0.1, DOC was 1.5±0.1mg / L, UV 254 0.038±0.005cm -1During the pre-chlorination treatment, a chlorine addition time sequence (i = 1, 2, 3 ... 7 (n = 7)) is set, and the corresponding chlorine addition amount at each moment is m i , respectively 0, 0.3, 0.6, 0.9, 1.2, 1.5 and 1.8 mg / L. The change of chlorine dosage between adjacent moments of the control system satisfies 0.2≤|m i+1 -m i |≤0.5, and the chlorine dosage does not exceed 3.0mg / L. The chlorine dosage is regulated according to the change of the fluorescence intensity ratio C1 / C2 k value. Through online data analysis, it reaches the maximum when the k value is 0.587, at which time the i+2th moment is 4, and the fluorescence intensity C13<C12(C1 i+1 <C1 i ), so the upper limit of chlorine dosage is m4, i.e. 0.9mg / L. Adjust the chlorine dosage to m3, i.e. 0.6mg / L. According to the preset algorithm conditions, the dosage of coagulant must meet the requirement that the DOC removal rate of the effluent after sedimentation should reach or exceed 20% (i.e. the ratio of effluent DOC to influent DOC ≤80%), and the UV of the effluent after sedimentation should reach or exceed 20%. 254 The removal rate should reach or exceed 35% (i.e. the effluent UV 254 UV 254 The ratio is ≤65%), the turbidity removal rate of the effluent water after sedimentation should reach or exceed 95% (i.e. the ratio of effluent turbidity to inlet turbidity is ≤5%), and the dosage of coagulant is controlled within the range of 0.04 to 0.15mM (in terms of Al or Fe). Through the adaptive adjustment of the system, the intelligent system adjusts the dosage of coagulant to 0.08mM (in terms of Fe). At this time, the turbidity removal rate of the effluent water reached 97.2%, the DOC removal rate was 26.9%, and the UV 254 The removal rate reached 40.8%. Compared with the traditional coagulation treatment process, the turbidity removal rate increased by 13.3 percentage points, the DOC removal rate increased by 8.8 percentage points, and the UV 254 The removal rate increased by 13.9 percentage points, and the dosage of coagulant was saved by 47%. Water Plant C also achieved the goal of moderate pre-oxidation to enhance coagulation and save chemical consumption.

Claims

1. A dosing system for pre-chlorination of source water, enhanced coagulation and algae removal, characterized by: It includes a raw water pump (1), a tubular static mixer (2), a flocculation tank (3), a sedimentation tank (4), a flow meter (5), an online temperature detector (6), an online turbidity detector ① (7), an online ultraviolet detector ① (8), an online organic matter analyzer ① (9), an oxidant tank (10), a metering pump ① (11), a metering pump ② (12), a coagulant tank (13), an online fluorescence detector (14), an online turbidity detector ② (15), an online ultraviolet detector ② (16), an online organic matter analyzer ② (17), a variable frequency speed controller ① (18), a variable frequency speed controller ② (19), and an industrial computer (20); The raw water pump (1), the tubular static mixer (2), the flocculation tank (3), and the sedimentation tank (4) are sequentially connected in series by pipelines, and source water is sent into the tubular static mixer (2) through the raw water pump (1); The flow meter (5), online temperature detector (6), online turbidity detector ① (7), online ultraviolet detector ① (8), and online organic matter analyzer ① (9) are arranged on the raw water inlet pipe, and the online fluorescence detector (14) is arranged on the flocculation tank (3) inlet pipe; the online turbidity detector ② (15), online ultraviolet detector ② (16), and online organic matter analyzer ② (17) are arranged on the sedimentation tank outlet pipe; The oxidant tank (10) is connected to the tubular static mixer (2) via a metering pump ① (11) to add the oxidant into the tubular static mixer (2). The oxidant may be a chlorine-based oxidant such as liquid chlorine, sodium hypochlorite, and bleaching powder; the coagulant tank (13) is connected to the tubular static mixer (2) via a metering pump ② (12) to add the coagulant into the tubular static mixer (2). The coagulant may be an aluminum salt coagulant (polyaluminum chloride, aluminum sulfate, polyaluminum sulfate, etc.) or an iron salt coagulant (ferric chloride, ferrous sulfate, ferric sulfate, etc.); The variable frequency speed controller ① (18) is electrically connected to the metering pump ① (11) for controlling the dosage of the oxidant; the variable frequency speed controller ② (19) is electrically connected to the metering ② (12) for controlling the dosage of the coagulant; the industrial computer (20) is electrically connected to the flow meter (5), the online temperature detector (6), the online turbidity detector ① (7), the online ultraviolet detector ① (8), the online organic matter analyzer ① (9), the online fluorescence detector (14), the online turbidity detector ② (15), the online ultraviolet detector ② (16), the online organic matter analyzer ② (17), the variable frequency speed controller ① (18) and the variable frequency speed controller ② (19), respectively. The flow meter (5) monitors the raw water flow in real time, the online temperature detector (6) monitors the raw water temperature in real time, the online turbidity detector ① (7) monitors the raw water turbidity in real time, and the online ultraviolet detector ① (8) monitors the raw water ultraviolet absorbance (UV 254 ), the online organic matter analyzer ① (9) monitors the concentration of dissolved organic carbon (DOC) in the raw water in real time, and the online fluorescence detector (14) simultaneously detects the characteristic fluorescent substances released after the algae cell membrane is damaged and the characteristic peak fluorescence intensity of humus-like substances related to natural organic matter; the above-mentioned collected data are transmitted to the industrial control computer (20), the online turbidity detector ② (15) monitors the turbidity of the precipitated water in real time, and the online ultraviolet detector ② (16) monitors the ultraviolet absorbance (UV 254 ), the online organic matter analyzer②(17) monitors the concentration of dissolved organic carbon (DOC) in the precipitated water in real time, and the industrial control computer (20) automatically adjusts the dosage of the reagent according to a preset algorithm.

2. A dosing system for pre-chlorination, enhanced coagulation and algae removal of water source water according to claim 1, characterized in that: The flocculation tank (3) is a mechanical reaction flocculation tank or a hydraulic reaction flocculation tank, such as a baffle reaction flocculation tank, a perforated plate reaction flocculation tank, a corrugated plate reaction flocculation tank, etc. The hydraulic retention time of the flocculation tank is 15 to 20 minutes, and the average velocity gradient is controlled at 20 to 50 seconds. -1 ; The sedimentation tank (4) is an inclined plate sedimentation tank, an inclined tube sedimentation tank or a horizontal flow sedimentation tank.

3. A refined intelligent control method using the drug delivery system according to claim 1 or 2, characterized in that: Through real-time data feedback and intelligent algorithm integration, intelligent control of the dosage of oxidant (chlorine) and coagulant (aluminum salt, iron salt) can be achieved respectively; (1) Determine the upper limit of the oxidant (chlorine) concentration and the corresponding chlorine concentration during actual operation: Based on the data feedback from the online temperature detector, especially when the water temperature is between 20°C and 30°C, the system determines that algae may explode and needs to adjust the pre-oxidant; The amount of chlorine added is dynamically adjusted according to the change of the fluorescence intensity ratio C1 / C2. The fluorescence intensity of C1 and C2 is detected online by an online fluorescence detector. C1 is a characteristic fluorescent substance released after the algae cell membrane is damaged, and C2 represents humus-like substances related to natural organic matter. The oxidant (chlorine) is first added using a time series model that is segmented by time, and the time points or time sequences of the addition are recorded as i=0, 1, 2, 3...n (n≥3), and the specific value of n can be designed as needed; The concentration of the oxidant (chlorine) added at the above n time points or moments (the concentration added to the pipeline) meets the following restrictions: the chlorine concentration variation range meets 0.2mg / L≤|m i+1 -m i |≤0.5mg / L, and 0.3mg / L≤m i ≤3.0mg / L; Chlorine dosing adopts a time series model with segmented time periods, and the raw water flow Q is calculated based on the dosing time point or time i. i and the chlorine concentration in the pipeline m i Design, dynamically adjust the speed of the oxidant metering pump to adjust the chlorine dosing pump flow rate q at time i i ,q i is the volume flow rate of the dosing (usually in L / h or m 3 / h), the calculation formula is shown in (1); Q i is the raw water flow rate at time i (in m 3 / h);m i is the chlorine concentration in the pipeline at time i (expressed in mg / L); ρ0 is the effective concentration of the oxidant in the oxidant tank (expressed in g / L or kg / m 3 express). In the time series i = 0, 1, 2, 3...n (n ≥ 3), the corresponding chlorine concentration at each moment is m i , the raw water flow is Q i , the corresponding chlorine dosing pump flow is q i ; The change rate of the fluorescence intensity ratio C1 / C2 is calculated as shown in formula (2): (C1 / C2) i represents the fluorescence intensity ratio C1 / C2 at time i; when the k value of formula (2) reaches the maximum at time i and C1 i+1 >C1 i When the upper limit concentration of chlorine is m i The actual later stable operation is based on the chlorine concentration m at time i-1. i-1 , the actual adjustment dosing pump flow is q i-1 ; When the k value of formula (2) reaches the maximum at time i and C1 i+1 <C1 i When the upper limit concentration of chlorine is m i+2 , the corresponding chlorine concentration m in the later actual operation i+1 , the actual adjustment dosing pump flow is q i+1 ; (2) After determining the chlorine concentration corresponding to the actual operation in step (1), the amount of coagulant added is finely regulated and determined based on the dissolved organic carbon (DOC) and ultraviolet absorbance (UV 254 ) and turbidity removal efficiency to dynamically adjust the coagulant dosage; when the raw water UV 254 ≤0.1cm-1, DOC≤2.5mg / L, turbidity<40NTU, the dosage of coagulant should meet the requirement that the DOC removal rate of the effluent after sedimentation reaches or exceeds 20% (i.e. the ratio of effluent DOC to influent DOC≤80%), and the UV 254 The removal rate should reach or exceed 35% (i.e. the effluent UV 254 UV 254 The ratio is ≤65%), the turbidity removal rate of the effluent water after sedimentation should reach or exceed 95% (that is, the ratio of the effluent turbidity to the inlet turbidity is ≤5%), and the dosage of the coagulant is controlled in the range of 0.04 to 0.15 mM (in terms of Al or Fe). After completing the time sequence of optimizing the dosage of oxidant (chlorine), the system automatically enters the next time sequence j=0, 1, 2, 3...n (n≥1), and the specific value of n can be set as needed; and the coagulant is added at different times j; According to the raw water flow Q j The coagulant metering pump speed is adjusted according to the coagulant dosage to adjust the coagulant dosing pump flow rate q at different times j , calculated by formula (3). j is the raw water flow at different times (in m 3 / h);m j is the concentration of coagulant in the pipeline at different times (expressed in mM, in Al or Fe, the concentration added to the pipeline); w0 is the mass fraction of Al or Fe in the coagulant (expressed in %), ρ0 is the effective concentration of the coagulant in the coagulant tank (expressed in g / L or kg / m 3 express); Start the optimization of coagulant dosage. The corresponding coagulant concentration at each moment is m j , the raw water flow is Q j , the corresponding coagulant dosing pump flow is q j ; At different times, the effluent water quality meets the target requirements, DOC 出水j / DOC 进水j ≤80%,UV 254出水j / With UV 254进水j ≤65%, T 出水j / T 进水j ≤5%, the system automatically optimizes the coagulant concentration to m at time j j , and adjust the dosing pump flow rate to the corresponding q j , in order to achieve the optimal dosage of coagulant; (3) Under the conditions corresponding to steps (1) and (2) for maintaining the raw water quality, perform the actual operation according to the corresponding chlorine concentration determined in step (1) and the amount of coagulant determined in step (2); (4) Time series trigger mechanism based on raw water quality fluctuations: When the system monitors the raw water quality changes in real time and compares it with the raw water quality at time i=0 in step (1), if it is found that the change amplitude of any of the following indicators exceeds the preset threshold, then steps (1) to (3) are repeated to automatically start the next time series and re-optimize the chlorine and coagulant addition strategy: turbidity change exceeds 3NTU, DOC change exceeds 0.2mg / L, UV 254 Changes greater than 0.005 cm - 1; (5) By designing and implementing the automatic control method based on the fluorescence intensity ratio and water quality parameters of the above steps (1) to (4), it is embedded in the industrial computer system for centralized control; the system collects water quality information in real time, and accurately adjusts the dosage of oxidant (chlorine) and coagulant based on the above intelligent control method.

4. The method according to claim 3, characterized in that Step (1) The concentration of the oxidant (chlorine) is gradually increased.

5. The method according to claim 3, characterized in that Applicable to algae density of 10 3 Up to 10 6 cells / mL, UV 254 Raw water conditions: ≤0.1cm-1, DOC≤2.5mg / L, turbidity<40NTU.

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