METHOD FOR MONITORING WATER QUALITY IN A SEAWATER DESALINATION SYSTEM.

Abstract

METHOD FOR MONITORING WATER QUALITY IN A SEAWATER DESALINATION SYSTEM This disclosure provides a method for monitoring the water quality of a seawater desalination system, including: obtaining water quality input parameters during a design phase; taking the water quality input parameters as design input quantities for the seawater desalination system, and monitoring a plurality of sampling points and chemicals used in the seawater desalination system; performing long-term monitoring of the water at the outlet of the pretreatment system, membrane system, industrial and domestic water system, and demineralized water system in the seawater desalination system during an assembly and commissioning phase;and the monitoring of water quality at the outlet of the pretreatment system, the membrane system, the industrial and domestic water system, and the demineralized water system in the seawater desalination system during an operational phase. By performing standardized water quality monitoring throughout the entire seawater desalination process, including the design, assembly and commissioning, and operational phases, this disclosure aims to address the problem in the existing experience-based monitoring process, in which significant safety risks are caused by substantial differences in monitoring quality and human error. Summary figure: Fig. 1;

Description

Title of the invention: METHOD FOR MONITORING THE QUALITY OF WATER IN A SEAWATER DESALINATION SYSTEM. technical field

[0001] This disclosure falls within the technical field of water quality monitoring in seawater desalination systems, and relates more particularly to a method for monitoring the water quality of a seawater desalination system. STATE OF THE ART

[0002] Seawater desalination consists of producing fresh water by desalinating seawater. This is an incremental, open-source technology for utilizing water resources, converting seawater into usable fresh water for purposes such as drinking water and industrial use. In this process, strict control of water quality is necessary to monitor the operating status of equipment and the quality of the produced water, thereby improving safety and economic benefits for downstream users.

[0003] The seawater desalination process system is large and complex, and each subsystem has different functions and materials, thus resulting in different risk points. Currently, units and personnel operating seawater desalination systems perform water quality monitoring solely on the basis of experience. This method of water quality monitoring relies excessively on individual ability and judgment based on experience, and it is extremely easy to cause significant safety risks due to large variations in the quality of monitoring and human error. SUMMARY

[0004] To this end, the present disclosure provides a method for monitoring the water quality of a seawater desalination system. By performing standardized water quality monitoring throughout the entire seawater desalination process, including the design, assembly and commissioning, and operational stages, the present disclosure aims to address the problem in the current experience-based method of water quality monitoring, in which significant safety risks are caused by large differences in monitoring quality and human error.

[0005] This disclosure provides a method for monitoring the water quality of a seawater desalination system, comprising: monitoring at least one water intake point corresponding to a water source intended to obtain the water quality input parameters in a design step of the seawater desalination;taking water quality input parameters as design input quantities of the seawater desalination system in the design stage of the whole seawater desalination process, and monitoring a plurality of sampling points on the seawater desalination system to satisfy the corresponding predefined requirements, where the plurality of sampling points are respectively taken from a pretreatment system, an ultrafiltration system, a first-stage reverse osmosis system, a second-stage reverse osmosis system, a cationic bed, an anionic bed, a mixed bed, a demineralized water tank, and a first-stage freshwater distribution system;monitoring of the chemicals used in the seawater desalination system to meet the corresponding predefined requirements in the design stage of the entire seawater desalination process; carrying out long-term monitoring of the water at the outlet of the pretreatment system, the membrane system, the industrial and domestic water system, and the demineralized water system in the seawater desalination system during the assembly and commissioning stage of the entire seawater desalination process, in order to ensure stable operation; and monitoring of the water quality at the outlet of the pretreatment system, the membrane system, the industrial and domestic water system, and the demineralized water system in the seawater desalination system during the operational stage of the entire seawater desalination process.

[0006] The beneficial effects of the technical solution according to this disclosure lie in the fact that: by dividing a complete seawater desalination process into a design stage, an assembly and commissioning stage, and an operation stage, and by providing water quality monitoring at the corresponding positions for the different stages, an arrangement of sampling points is made for a pretreatment process, a membrane process, and a demineralization process, and the water quality of the seawater desalination is guided according to the different stages, thus ensuring that the water quality is well monitored at the different stages of design, assembly and commissioning, and operation, in order to achieve the objectives of reducing safety risks, improving the quality of the water at the outlet and enhancing the safety and economy of the operation of the system.In addition, a quality monitoring solution is provided for each subsystem in the seawater desalination system, . and the process is controlled. The effect of preventing problems before they occur is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] [Fig.1] shows a diagram of a sampling point arrangement of a pretreatment system provided by an embodiment of the present disclosure;

[0008] [Fig.2] shows a diagram of a sampling point arrangement of an ultrafiltration system provided by an embodiment of the present disclosure;

[0009] [Fig.3] shows a diagram of a sampling point arrangement of a first-phase reverse osmosis system provided by an embodiment of the present disclosure;

[0010] [Fig.4] shows a diagram of a sampling point arrangement of a second-phase reverse osmosis system provided by an embodiment of the present disclosure;

[0011] [Fig.5] shows a diagram of a sampling point arrangement of a cationic bed provided by an embodiment of the present disclosure;

[0012] [Fig.6] shows a diagram of an arrangement of sampling points of an anionic bed provided by an embodiment of the present disclosure;

[0013] [Fig.7] shows a diagram of a sampling point arrangement of a mixed bed provided by an embodiment of the present disclosure;

[0014] [Fig. 8] shows a diagram of a sampling point arrangement of a demineralized water tank supplied by an embodiment of the present disclosure; and

[0015] [Fig.9] shows a diagram of a sampling point arrangement of a first-phase freshwater distribution system provided by an embodiment of the present disclosure.

[0016] In [Fig. 1]: seawater 1, sodium hypochlorite 2, flocculant 3, sampling point after mixer 4, coagulation aid 5, flocculation tank 6, sedimentation tank 7, sampling point at the outlet of the sedimentation tank 8, filter tank 9, sampling point after the filter tank 10, sampling point at the clear water tank 11, clear water tank 12. In [Fig. 2]: sampling point at the clear water tank 11, clear water tank 12, self-cleaning filter 13, ultrafiltration module 14, sampling point at the inlet of the ultrafiltration module 15, sampling point at the outlet of the ultrafiltration module 16, ultrafiltration-produced water tank 17, sampling point at the water produced by ultrafiltration 18, sampling pump 19, dedicated sampling point for SDL5 of water produced by ultrafiltration 20. In [Fig.3] : tank of water produced by ultrafiltration 17, sampling point of the tank of water produced by ultrafiltration 18, safety filter 21, sampling point of water at the inlet of the . first phase reverse osmosis module 22, first phase reverse osmosis module 23, water sampling points at the outlet of individual membranes of first phase reverse osmosis module 24 / 25 / 26 / 27, water sampling point at the outlet of first phase reverse osmosis module 28, first phase freshwater tank 29, first phase freshwater tank sampling point 30, dedicated sampling pump 31, first phase freshwater SDIi5 sampling point 32. In [Fig.4]: First-stage freshwater tank 29, first-stage freshwater tank sampling point 30, safety filter 33, second-stage reverse osmosis module inlet water sampling point 34, second-stage reverse osmosis module 35, second-stage reverse osmosis module outlet water sampling points 36 / 37 / 38 / 39, second-stage reverse osmosis module outlet water sampling point 40, second-stage freshwater tank 41, second-stage freshwater tank sampling point 42. In [Fig. 5]: Second-stage freshwater main line 43, cation bed outlet sampling point 44, resin collector 45, cation bed outlet main line 46. In [Fig.6]: main line at the outlet of the cationic bed 46, sampling point at the outlet of the anionic bed 47, resin collector 48, main line at the outlet of the anionic bed 49. In [Fig.7]: main line at the outlet of the anionic bed 49, sampling point at the outlet of the mixed bed 50, resin collector 51, main line at the outlet of the mixed bed 52. In [Fig.8]: main line at the outlet of the mixed bed 52, demineralized water tank 53, sampling point in the demineralized water tank 54. In [Fig.9] : first phase fresh water tank 29, first phase fresh water booster pump 55, second phase reverse osmosis line 56, calcium chloride dosing point 57, industrial water sampling point 58, industrial water tank 59, industrial water supply pump 60, industrial water line 61, calcium chloride and sodium hypochlorite dosing point 62, domestic water tank 63, domestic water sampling point 64, domestic water supply pump 65, domestic water line 66. . DETAILED DESCRIPTION OF THE IMPLEMENTATION METHODS.

[0017] The technical solutions in the embodiments of this disclosure will be clearly and fully described below in connection with the drawings in the embodiments of this disclosure. Obviously, the embodiments described are only a part of the embodiments of this disclosure, and not all of them. Based on the embodiments in this disclosure, all other embodiments obtained by a no person in the trade without making an inventive effort is within the scope of protection of this disclosure.

[0018] This disclosure provides at least one embodiment of a method for monitoring the water quality of a seawater desalination system, and the method for monitoring the water quality of the seawater desalination system includes the following steps.

[0019] SI: monitoring of at least one water intake point corresponding to a water source intended to obtain water quality input parameters in a seawater desalination design phase.

[0020] It should be noted that if at least one water intake point comprises several water intake points, individual monitoring is carried out for each of the multiple water intake points. Long-term monitoring can be performed for at least one water intake point corresponding to the intended water source.

[0021] S2: taking water quality input parameters as design input quantities of the seawater desalination system in the design phase of the complete seawater desalination process, and monitoring a plurality of sampling points on the seawater desalination system to satisfy corresponding predefined requirements, where the plurality of sampling points are respectively taken from a pretreatment system, an ultrafiltration system, a first-stage reverse osmosis system, a second-stage reverse osmosis system, a cationic bed, an anionic bed, a mixed bed, a demineralized water tank, and a first-stage freshwater distribution system.

[0022] Water quality input parameters are crucial for the design of the seawater desalination system and can be used to adjust the operating conditions of the seawater desalination system according to the design input quantities.

[0023] In some embodiments, the worst measured result can be taken as the design input quantity, and at least a design margin of 30% is reserved.

[0024] S3: monitoring of the chemicals used in the seawater desalination system to meet the corresponding predefined requirements during an assembly and commissioning phase and an operation phase of the entire seawater desalination process.

[0025] S4: carrying out long-term monitoring of the water at the outlet of the pretreatment system, the membrane system, the industrial and domestic water system, and the demineralized water system in the seawater desalination system during a phase of assembly and commissioning of the entire seawater desalination process, in order to ensure stable operation.

[0026] It should be noted that the subsystems in the seawater desalination system include a pretreatment system, a membrane system, an industrial and domestic water system, and a demineralized water system. The membrane system may include an ultrafiltration system, a first reverse osmosis stage, and a second reverse osmosis stage.

[0027] S5: monitoring of water quality at the outlet of the pretreatment system, membrane system, industrial water system and domestic water system, and demineralized water system in the seawater desalination system during an operational phase of the entire seawater desalination process.

[0028] According to the technical solution provided in the example of the embodiment of this disclosure, by dividing the whole seawater desalination process into a design phase, an assembly and commissioning phase, and an operation phase, and by providing water quality monitoring at the corresponding positions for different phases, an arrangement of sampling points is made for a pretreatment process, a membrane process, and a demineralization process, and the water quality of the seawater desalination is guided according to different phases, in order to ensure that the water quality is well supervised in different phases of design, assembly and commissioning, and operation, in order to achieve the objectives of reducing safety risks, improving the quality of the water at the outlet, and strengthening the safety and economy of the operation of the system.Furthermore, a water quality monitoring solution is provided for each subsystem in the seawater desalination system, and the process is controlled. The effect of preventing problems before they occur is achieved.

[0029] In at least one example of an embodiment of this disclosure, S 1.1 is a specific implementation of S1 above.

[0030] S 1.1: Monitoring the quality of seawater under different seasons and tidal levels during the design phase of the entire seawater desalination process in order to meet a first water quality index, provided that the intended water source is seawater, the first water quality index comprising turbidity, permanganate index, total iron, pH25, temperature, anionic surfactants, sodium ions, chloride ions, sulfate radicals, hardness, calcium ions, magnesium ions, nitrate radicals, manganese, copper and algae; and

[0031] carry out the inspection of seawater quality and hydrological conditions at the project site, and focus on water quality conditions under different seasons and different tidal levels.

[0032] In at least one embodiment of this disclosure, S 1.2 is a specific implementation of the above SI.

[0033] S 1.2: monitor the water quality of the hot wastewater during the phase of design of the entire seawater desalination process to satisfy a second water quality index, under a condition where the intended water source is warm wastewater, the second water quality index including turbidity, permanganate index, total iron, pH25, temperature, anionic surfactants, sodium ions, chloride ions, sulfate radicals, hardness, calcium ions, magnesium ions, nitrate radicals, manganese, copper, algae, total phosphorus, nitrogen ammonia and hydrocarbons.

[0034] It should be noted that the sources of pollution of hot wastewater may also be subject to special attention.

[0035] For cases where the intended water source is seawater and warm wastewater, the corresponding water quality indices are presented in Table 1 below.

[0036] [Tables 1 Sample Index Name (including, but not limited to) Seawater Turbidity, Permanganate Index, Total Iron, pH25, Temperature, Anionic Surfactant, Sodium Ion, Chloride Ion, Sulfate Radical, Hardness, Calcium Ion, Magnesium Ion, Nitrate Radical, Manganese, Copper, Algae Warm Drainage Water "Seawater" Index + Total Phosphorus, Ammoniacal Nitrogen, Petroleum Table 1: Water quality indices at the design stage.

[0037] In at least one embodiment of this disclosure, after S3, S31 and S32 are further included.

[0038] S31: Continued monitoring to verify if the first water quality index or the second water quality index does not exceed the predefined value during the assembly and commissioning phase of the entire seawater desalination process.

[0039] S32: Evaluation to determine if the seawater desalination system can resist when the first water quality index or the second water quality index exceeds the predefined value.

[0040] S33: upgrade of the seawater desalination system when the system of Seawater desalination cannot withstand it.

[0041] In at least one embodiment of this disclosure, during the operational phase of the entire seawater desalination process, a water monitoring frequency at the outlet of each subsystem in the system seawater desalination is less than a water supervision frequency at the outlet of each subsystem during the assembly and commissioning phase of the entire seawater desalination process.

[0042] In at least one embodiment of this disclosure, as shown in Table 2, the multiple sampling points include a water source inlet 1, a dosing mixer outlet 4, a settling tank outlet 8, a clear water tank sampling point 11, an ultrafiltration module inlet 15, an ultrafiltration module outlet 16, an ultrafiltration-produced water tank sampling point 18, a dedicated SDIi5 ultrafiltration-produced water sampling point 20, a first-stage reverse osmosis module water inlet sampling point 22, single membrane outlets of the first-stage reverse osmosis module 24 / 25 / 26 / 27, water at the outlet of the first-stage reverse osmosis module 28, a first-stage freshwater tank sampling point 30, a point dedicated sampling for first-phase fresh water SDIi5 32, a water inlet from the second-phase reverse osmosis module 34,water at the outlet of the second-phase reverse osmosis module 40, outlets of a single membrane of the second-phase reverse osmosis module 36 / 37 / 38 / 39, a sampling point of the second-phase fresh water tank 42, an outlet of the cationic bed 44, an outlet of the anionic bed 47, an outlet of the mixed bed 50, a sampling point of a demineralized water tank 54, a sampling point of the industrial water tank 58 and a sampling point of the domestic water tank 64.

[0043] [Tables2] Sampling location Arrangement form Purpose Water source inlet (in [Fig. 1], 1) One inlet per row, same pipeline as the inline inlet meter Monitoring of inlet water quality, facilitating adjustment of system conditions according to water quality Dosing mixer outlet (in [Fig. 1], 4) One per mixer, arranged on a separate outlet line Monitoring of the dosing mixing effect, dosing control Settling basin outlet (in [Fig. 1], 8) One per settling basin, arranged separately Evaluation of flocculation and settling effects Clear water tank sampling point (in [Fig. 1], 11) One per clear water tank, arranged separately Evaluation of the filter's filtration effect Ultrafiltration module inlet (in [Fig.2], 15) One per ultrafiltration inlet, arranged separately. Evaluation of the usability of the individual ultrafiltration module. Ultrafiltration module outlet (in [Fig. 2], 16) One per ultrafiltration outlet, arranged separately. Evaluation of the usability of the individual ultrafiltration module. Sampling point of the ultrafiltration product water tank (in [Fig. 2], 18) One per ultrafiltration water tank, arranged separately. Evaluation of the ultrafiltration effect. Dedicated sampling point for the SDL5 ultrafiltration product water (in [Fig. 2], 20) Arranged separately at the ultrafiltration tank outlet, equipped with a dedicated sampling pump. Dedicated to measuring SDL5. Sampling point of the inlet water of the first-stage reverse osmosis module (in [Fig. 2], 19). g. 3], 22) Taken from the water inlet pipe of each first-stage reverse osmosis module. Evaluation of the effect of the safety filter. First-stage reverse osmosis module inlet water (in [Fig. 3], 28) Taken from the outlet line of each first-stage reverse osmosis module Evaluation of the effect of the individual module Outlets of a single membrane of the first-stage reverse osmosis module (in [Fig. 3], 24 / 25 / 26 / 27) Taken from the outlet line of the individual first-stage reverse osmosis membrane Dedicated to diagnosing membrane damage First-stage freshwater tank sampling point (in [Fig. 3], 30) One per first-stage freshwater tank, arranged separately First-stage freshwater quality detection Dedicated sampling point for SDIi5 of first-stage freshwater (in [Fig.3], 32) Placed separately at the outlet of the first-phase freshwater tank, equipped with a dedicated sampling pump. Measurement of the SDIi5 of the first-phase freshwater. Inlet water of the second-phase reverse osmosis module (in [Fig. 4], 34). Taken from the water inlet line of each second-phase reverse osmosis module. Evaluation of the effect of the safety filter. Water at the outlet of the second-phase reverse osmosis module (in [Fig. 4], 40). Taken from the outlet line of each second-phase reverse osmosis module. Evaluation of the effect of the individual module. Outlets of a single membrane of the second-phase reverse osmosis module (in [Fig. 4], 36 / 37 / 38 / 39). Taken from the outlet line of the individual membranes. individual second phase reverse osmosis Dedicated to the diagnosis of membrane damage Second phase fresh water tank sampling point (in [Fig.4], 42) One per second phase fresh water tank, arranged separately. Detection of second phase fresh water quality. Sampling point of the second freshwater phase tank (in [Fig. 4], 42) One for each second freshwater phase tank, arranged separately. Detection of second-phase freshwater quality. Cationic bed outlet (in [Fig. 5], 44) Sampled from the outlet pipe of each row of cationic bed, outlet collectors arranged separately. Evaluation of the demineralization effect of the cationic bed. Anionic bed outlet (in [Fig. 6], 47) Sampled from the outlet pipe of each row of anionic bed, outlet collector arranged separately. Evaluation of the demineralization effect of the anionic bed. Mixed bed outlet (in [Fig. 7], 50) Sampled from the outlet pipe of each row of mixed bed, collector. Separately arranged outlet. Evaluation of the demineralization effect of the mixed bed.

[0044] In at least one embodiment of this disclosure, S3.1 to S3.8 are specific implementations of S3 above.

[0045] S3.1: During the design phase of the entire desalination process Seawater, random sampling, and testing for potential chemicals may be adopted to ensure the quality of chemicals entering the plant. S3.2: Monitoring the concentration of an alkaline solution prepared in an alkaline solution dosing tank to verify that it is within a normal range. S3.3: Monitoring the concentration of an acidic solution prepared in an acid solution dosing tank to verify that it is within a normal range. S3.4: Monitoring the concentration of a reducing agent prepared in a reducing agent dosing tank to verify that it is within a normal range. S3.5: Monitoring the concentration of an oxidizing agent prepared in an oxidizing agent dosing tank to verify that it is within a normal range. S3.6: Monitoring the concentration of a prepared scaling inhibitor in a scaling inhibitor dosing tank to verify that it is within a normal range. S3.7: Monitoring the concentration of a prepared flocculant in a flocculant dosing tank to verify that it is within a normal range. S3.8: Monitoring the concentration of a prepared coagulation adjuvant. in a coagulation adjuvant dosing tank, in order to verify that it is within a normal range.

[0046] It should be noted that the arrangement forms and purposes of the respective tank trucks and dosing tanks are presented in Table 3.

[0047] [Tables3] Location | Layout | Purpose | Tanker Truck | Temporary Sampling by Lifting the Tanker Truck | Inspection of the Quality of Chemicals Entering the Plant | Alkaline Solution Dosing Tank | Arranged on a Drain Valve | Verification of the Normal Concentration of the Alkaline Solution | Acid Solution Dosing Tank | Arranged on a Drain Valve | Verification of the Normal Concentration of the Acid Solution | Reducing Agent Dosing Tank | Arranged on a Drain Valve | Verification of the Normal Concentration of the Reducing Agent | Oxidizing Agent Dosing Tank | Arranged on a Drain Valve | Verification of the Normal Concentration of the Oxidizing Agent | Scale Inhibitor Dosing Tank | Arranged on a Drain Valve | Verification of the Normal Concentration of the Scale Inhibitor | Flocculant Dosing Tank | Arranged on a Drain Valve | Verification of the Normal Concentration of the Flocculant | Adjuvant Dosing Tank Coagulant Arrangedon a drain valve. Verification of the normal concentration of the coagulant adjuvant. Table 3: Arrangement forms and objectives of road tanks and measuring tanks.

[0048] In at least one embodiment of this disclosure, S21 is further included before or after the above S3.

[0049] S21: Performing effect verification tests on different flocculants for determine an optimal flocculant during the design phase of the entire seawater desalination process.

[0050] The selection of the flocculant is determined according to the water quality conditions, including: 1, in the selection of iron-based flocculants, focusing on the total iron content initially present in the seawater and a total iron concentration range acceptable for ultrafiltration and reverse osmosis membranes; and 2, performing simulation effect tests of flocculation, i.e. "beaker tests", to compare different flocculants, and record the turbidity removal rate, the organic matter removal rate, the total residual iron post-flocculation (when using iron-based flocculants), the optimal dosage quantity, and other indicators.

[0051] In at least one embodiment of this disclosure, S22 is further included after S21 above.

[0052] S22: Performing further simulation tests on flocculant dosages and coagulation aids for a pretreatment system during a flocculation and settling phase in the assembly and commissioning phase of the entire seawater desalination process, and determination of an optimal dosage concentration by testing different concentrations of flocculants and coagulation aids.

[0053] In at least one embodiment of this disclosure, at least one of S4.1 to S4.21 is a specific implementation of the above S4.

[0054] S4.1: measurement of residual chlorine at the outlets of a dosing mixer and a tank settling of a pretreatment system in the assembly and commissioning phase of the entire seawater desalination process, evaluation of the effect of an oxidizing agent, and adjustment of a dosage concentration of the oxidizing agent according to the effect of the oxidizing agent.

[0055] S4.2: Daily sampling of a clear water tank in the system of Pretreatment and regular inspection of the upper water in the clear water tank.

[0056] In this way, daily sampling monitoring of the clear water tank is carried out in conjunction with regular inspection of the upper water of the clear water tank, thus making it possible to effectively avoid the deterioration of water quality caused by the accumulation of floating substances.

[0057] S4.3: calculation of the Langelier index before and after use of an inhibitor scale buildup for the membrane system, obtaining an effect of the current concentration of the scale inhibitor, and adjusting a dosage concentration of the scale inhibitor according to the effect of the current concentration of the scale inhibitor.

[0058] S4.4: Measurement of the redox potential before and after use of a reducing agent for the Membrane system, obtaining an effect of the current concentration of the reducing agent, and adjusting a reductant dosage concentration according to the effect of the current concentration of the reducing agent. The redox potential is abbreviated as ORP.

[0059] S4.5: Measurement of organic matter content in wastewater after assembly ultrafiltration membranes and reverse osmosis membranes and the initial filling of the membrane system with water, ensuring that the organic matter content does not exceed the total organic carbon (TOC) of the water. the inlet; and carrying out an additional rinse when the organic matter content exceeds the TOC of the water at the inlet.

[0060] S4.6: Inspection, for the membrane system, of the inlet water and the water to the outlet of each ultrafiltration membrane when the water quality of the ultrafiltration tank is abnormal; and additional inspection of the pretreatment system when the inlet water quality causes the anomaly.

[0061] S4.7: guidance for the dosing of the corresponding chemicals for the systems industrial and domestic water by measuring alkalinity, hardness and residual chlorine in the industrial water tank and the domestic water tank.

[0062] S4.8: Regular inspection of the water quality in the demineralized water tank, of the cationic bed outlet, anionic bed outlet and mixed bed outlet for the demineralized water system.

[0063] S4.9: Performing an additional inspection before reuse when the tank demineralized water was inactive for more than 10 days.

[0064] S4.10: Monitoring of the inlet seawater of the pretreatment system for verify that it complies with the corresponding measurement indices of the incoming seawater during the assembly and commissioning phase of the entire seawater desalination process, the corresponding measurement indices of the incoming seawater including a temperature range of 5°C to 40°C.

[0065] The measurement indices and corresponding frequencies of the inlet seawater (1 in [Fig.1]) are detailed in Table 4 below.

[0066] [Tables4] Temperature Index, °C Turbidity, NTU Specification 5~40 / Method: pH meter, thermometer Turbidimetry by scattered light Frequency: Once a day Once a day Table 4: Corresponding measurement indices and frequencies of the inlet water of the seawater intake (1 in [Fig.1]).

[0067] Note: If the turbidity result is high, the dose of flocculant is increased; if the turbidity is low, the dose of flocculant is decreased and a coagulation adjuvant is added.

[0068] S4.11: monitoring compliance with measurement indices corresponding to the output of the settling tank in the pretreatment system during the assembly and commissioning phase of the entire seawater desalination process, the measurement indices corresponding to the outlet of the settling tank including a temperature range of 5°C to 40°C and a turbidity of less than 5 NTU.

[0069] The corresponding measurement indices and the frequencies of the outlet of the settling tank (8 in [Fig.1]) are detailed in Table 5 below.

[0070] [Tables5] Temperature Index, °C Turbidity, NTU Specification 5~40 <5 Method: pH meter, thermometer Turbidimetry by diffused light Frequency: Once a day Once a day Table 5: Corresponding measurement indices and frequencies of the outlet of the settling tank (8 in [Fig.1]).

[0071] If the turbidity result is high, the dosage of flocculant is increased.

[0072] In at least one embodiment of this disclosure, S4.2.1 is a specific implementation of S4.2 above.

[0073] S4.2.1: monitoring that the water at the outlet of the pretreatment system satisfies the corresponding measurement indices of the water at the outlet of the pretreatment during the assembly and commissioning phase of the entire seawater desalination process, where the corresponding measurement indices of the water at the outlet of the pretreatment include a temperature range of 5°C to 40°C, a turbidity of less than 1 NTU and a total iron of less than 0.15 pg / L.

[0074] It should be noted that the water at the outlet of the pretreatment refers to the quality of the water in the clear water tank.

[0075] The corresponding measurement indices and frequencies of the water at the outlet of the pretreatment are detailed in Table 6 below.

[0076] [Tableauxô] Temperature Index, °C Turbidity, NTU Total Iron, mg / L Specification 5~40 <1 <0.15 Method pH meter, thermometer Light scattering turbidity method Phenantroline method Frequency Once a day Once a day Once a week Table 6: Corresponding measurement indices and frequencies of water at the outlet of the pretreatment (sampling point of tank 11 of clear water in [Fig.1]).

[0077] If the turbidity result is high, the flocculant dose is increased; if the total iron is high, the flocculant dose is decreased.

[0078] S4.12: monitoring that the water at the outlet of the membrane system meets the corresponding measurement indices of the water at the ultrafiltration outlet, where the corresponding measurement indices of the water at the ultrafiltration outlet include a range of temperature ranging from 5°C to 40°C, SDIi5 <3, turbidity < 0.2 NTU and pH25 in a range of 4 to 11.

[0079] The corresponding measurement indices and frequencies of the water at the outlet of the ultrafiltration are detailed in Table 7 below.

[0080] [Tables7 Temperature Index, °C sdi15 Turbidity, NTU pH25 Specification 5~40 <3 <0.2 4~11 Method pH meter, thermometer Manual method Scattered light turbidimetry Electrode method Frequency Once a day Once a week Once a day Once a day Table 7: Corresponding measurement indices and frequencies of water at the outlet of ultrafiltration (16 in [Fig.2]).

[0081] If the turbidity or SDIi5 result is high, the ultrafiltration membrane should be checked for damage, or membrane cleaning should be intensified.

[0082] S4.13: Monitoring the conformity of the inlet water of the first phase module reverse osmosis of the membrane system to the corresponding measurement indices of the inlet water intake point of the first stage reverse osmosis module, the corresponding measurement indices of the inlet water intake point of the first stage reverse osmosis module including a temperature range of 5°C to 40°C, SDIi5<5, residual chlorine <0.1 mg / L, pH25 in a range of 4 to 11 and redox potential <200 mV.

[0083] [Tables8] Temperature Index, °C sdi15 Residual Chlorine, mg / L pH25 Redox Potential, mV Specification 5~40 <5 <0.1 4~11 <200 Method pH meter, thermometer Manual method DPD method Electrode method Electrode method Frequency Measurement before start Measurement before start Measurement before start Measurement before start Measurement before start Table 8: Corresponding measurement indices and frequencies of the inlet water sampling point of the first phase reverse osmosis module (22 in [Fig.3]).

[0084] If the redox potential result is high, the dosage of the reducing agent is increased; if SDI15 is high, the dosage of the scale inhibitor is increased or the operating conditions of the ultrafiltration are checked; if the residual chlorine is high, the dosage of sodium hypochlorite in the seawater is decreased.

[0085] S4.14: Monitoring of water quality compliance at the sampling point of the first phase fresh water tank of the membrane system with the corresponding measurement indices of the first phase fresh water tank, where the corresponding measurement indices of the first phase fresh water tank include a temperature range of 5°C to 40°C, SDIi5 < 5, residual chlorine <0.1 mg / L, pH25 in a range of 4 to 11, and conductivity < 1000 qS / cm.

[0086] The corresponding measurement indices and the sampling point frequencies of the first phase fresh water tank are detailed in Table 9 below.

[0087] [Tables9] Temperature Index, °C sdi15 Residual Chlorine, mg / L pH25 Conductivity, μ S / cm Specification 5~40 <5 <0.1 4~11 <1000 Method pH25 meter, thermometer Manual Method DPD Method Electrode Method Electrode Method Frequency Once a day Once a week Once a day Once a day Once a day Table 9: Corresponding measurement indices and frequencies of the sampling point of the first freshwater phase tank (30 in [Fig.3])

[0088] If SDI15 is high, membrane cleaning is enhanced; if residual chlorine is high, sodium hypochlorite dosage in seawater is decreased; if conductivity is high, conductivity at the outlet of each reverse osmosis membrane is checked.

[0089] S4.15: Monitoring the water quality of the second freshwater phase tank in the membrane system satisfies the corresponding measurement indices of the sampling point of the second freshwater phase tank, where the corresponding measurement indices of the sampling point of the second freshwater phase tank include a temperature range of 5°C to 40°C, TDS<50 mg / L, and pH25 in a range of 6.5 to 8.5.

[0090] [TableauxlO] Temperature Index, °C STD, mg / L pH25 Specification 5-40 <50 6.5-8.5 Method pH meter, thermometer Drying Method Electrode method Frequency Once a day Once a day Once a day Table 10: Corresponding measurement indices and frequencies of the sampling point of the second freshwater phase tank (42 in [Fig.4]).

[0091] If the TDS is high, membrane cleaning is intensified; if residual chlorine is high, the dosage of sodium hypochlorite in seawater is reduced; if conductivity is high, the conductivity at the outlet of each reverse osmosis membrane is checked to identify the damaged membrane component.

[0092] S4.16: Monitoring of the water at the outlet of the cation bed to verify if it satisfies to the corresponding measurement indices of the sampling point of the cationic bed outlet, the corresponding measurement indices of the sampling point of the cationic bed outlet including sodium less than or equal to 3 pg / L.

[0093] The corresponding measurement indices of the sampling point of the cationic bed outlet are detailed in Table 11 below.

[0094] [Tables II] Sodium Index Specification <3 Method Flame method, electrode method Frequency Each water production Table 11: Corresponding measurement indices and sampling point frequencies of the cationic bed outlet (44 in [Fig.5]).

[0095] If the sodium content is high, the cation bed is regenerated.

[0096] S4.17: Monitoring the conformity of the water at the outlet of the anionic bed to corresponding measurement indices of the anionic bed outlet, the corresponding measurement indices of the anionic bed outlet including a conductivity < 5 pS / cm and a soluble silica < 50 pg / L.

[0097] The measurement indices and corresponding frequencies of the anionic bed output are detailed in Table 12 below.

[0098] [Tables 12] Conductivity index, pS / cm Soluble silica, pg / L Specification <5 <50 Method Electrode method Spectrophotometry method Frequency Each time of water production Each time of water production Table 12: Corresponding measurement indices and anion bed output frequencies (47 in [Fig.6]).

[0099] If the conductivity or soluble silica is high, the anionic bed is regenerated.

[0100] S4.18: Monitoring the conformity of water at the outlet of the mixed bed to the indices corresponding measurement indices of the mixed bed outlet, said corresponding measurement indices of the mixed bed outlet including chloride ions < 1 pg / L, sulfate radicals < 1 pg / L, conductivity < 0.15 pS / cm, TOC < 100 pg / L, soluble silica < 10 pg / L, pH25 in a range of 6.5 to 8.0 and sodium < 3 pg / L.

[0101] The corresponding measurement indices and the frequencies of the mixed bed outlet are detailed in Table 13 below.

[0102] [Tables 13] Chloride ion index pg / L Tallow radical pg / L Conductivity pg / L TOC pS / cm Soluble silica pg / L pH25 pg / L Sodium pg / L Specification <1 <1 <0.15 <100 <10 6.5 ~8.0 <3 Method Chromatography Chromatography Method Met Method by Met Ioniq ioniq ioniq by electrode p spectrophoto ioniq ioniq ioniq ioniq iono ... Table 13: Corresponding measurement indices and frequencies of the mixed bed outlet (50 in [Fig.7]).

[0103] If an index other than pH is relatively high, regeneration of the mixed bed is necessary.

[0104] S4.19: Monitoring of the quality of the demineralized water tank satisfactory to the corresponding measurement indices of the demineralized water tank sampling point, where the corresponding measurement indices of the demineralized water tank sampling point include chloride ions < 50 qg / L, sulfate radical < 50 qg / L, conductivity <1.2 qS / cm, total organic carbon (TOC) < 500 qg / L, soluble silica < 20 qg / L and pH25 in a range of 6.5 to 8.0.

[0105] The corresponding measurement indices of the sampling point of the demineralized water tank are detailed in Table 14 below.

[0106] [Tables 14] Chloride ion index (qg / L) Sulfate radical (qg / L) Conductivity (qS / cm) TOC (qg / L) Soluble silica (qg / L) pH25 Specification <50 <50 <1.2 <500 <20 6.5-8.0 Frequency Once a day Once a day Once a day Once a day Once a day Once a day Once a day Table 14: Corresponding measurement indices and frequencies of the sampling point of the demineralized water tank (54 in [Fig.8]).

[0107] If any index deviates, the states of the mixed bed, the anionic bed and the cationic bed must be checked in sequence.

[0108] S4.20: Monitoring the conformity of industrial water to measurement indices corresponding to the industrial water sampling point, where the corresponding measurement indices of the industrial water sampling point include a temperature between 5°C and 40°C, a total hardness > 40 mg / L, an alkalinity > 40 mg / L, a pH25 between 8.0 and 9.0, and a Langelier index > 0.5.

[0109] The corresponding measurement indices of the industrial water sampling point are detailed in Table 15 below.

[0110] [Tables 15] Temperature Index, °C Total Hardness, mg / L Alkalinity, mg / L pH25 Langelier Index Specification 5-40 >40 >40 8.0-9.0 >0.5 Method pH meter, thermometer Titration method, electrode method Titration method Electrode method Online Frequency Once a day. Once a week. Once a week. Once a day Once a week. Table 15: Corresponding measurement indices and frequencies of the industrial water sampling point (58 in [Fig.9]).

[0111] If the hardness or Langelier index is relatively low, the amount of calcium chloride dosage is increased; if the alkalinity is too low, the amount of sodium bicarbonate or sodium carbonate dosage is increased.

[0112] S4.21: monitoring to verify whether domestic water meets measurement indices corresponding to the domestic water sampling point, said corresponding measurement indices of the domestic water sampling point including a residual chlorine range of 0.3 mg / L to 2.0 mg / L, a permanganate index < 3 mg / L, a turbidity < 1 NTU, a pH25 range of 6.0 to 9.0, a total number of bacteria < 100 and a total coliform group of 0 / 100 mL.

[0113] The corresponding measurement indices of the domestic water sampling point are detailed in Table 16 below.

[0114] [Tableauxlô] Residual Chlorine Index, mg / L Permanganate Index, mg / L Turbidity, NTU PH25 Total Bacterial Count, CFU / mL Total Coliform Group, cells / 100 mL Specification 0.3-2.0 <3 <1 6.0-9.0 <100 0 Method DPD Method Titration Method Nephelometric Method Electrode Method Manual Method Manual Method Frequency Once a day Once a week Once a week Once a day Once a day Once a day Table 16: Corresponding measurement indices and frequencies of the domestic water sampling point (64 in [Fig.9]).

[0115] If bacterial indicators exceed the standard, it is necessary to increase the dose of disinfectant.

[0116] In at least one embodiment of this disclosure, at least one of S5.1 and S5.4 is a specific implementation of the above S5.

[0117] S5.1: periodically measure the water quality of a clear water tank in a pretreatment system during the operating phase of the entire seawater desalination process, and periodically check the upper water of the clear water tank.

[0118] It should be noted that if the quality of the clear water tank is abnormal, it is necessary to check the water quality conditions of each connection of the pretreatment system.

[0119] S5.2: periodically measure the water quality of the ultrafiltered water tank, the first fresh water tank and the second fresh water tank in the membrane system.

[0120] It should be noted that if the membrane system is abnormal, it is necessary to check each membrane module.

[0121] S5.3: periodically inspect the water quality of the industrial water tank and of the domestic water tank in the industrial and domestic water system.

[0122] For example, measuring the alkalinity, hardness and residual chlorine of the industrial water tank and the domestic water tank can guide the dosage of the corresponding chemicals.

[0123] S5.4: periodically inspect the quality of the water in the demineralized water tank in the demineralized water system.

[0124] It should be noted that if the quality of the water in the demineralized water tank is abnormal, it is necessary to check the effectiveness of each demineralization bed.

[0125] In at least one embodiment of this disclosure, S5.1.1 is a specific implementation of S5.1 above.

[0126] S5.1.1: monitor whether the **water at the outlet** of the pretreatment system meets to the corresponding measurement indices of **water at the outlet** of the pretreatment, where the corresponding measurement indices of **water at the outlet** of the pretreatment include a temperature range of 5°C to 40°C and a turbidity < 1 NTU.

[0127] The corresponding measurement indices and frequencies of **water at the outlet** of the pretreatment are detailed in Table 15 below.

[0128] [Tables 15] Temperature Index, °C Turbidity, NTU Specification 5~40 <1 Method pH meter, thermometer Light scattering turbidity nephelometry Frequency Once a week Once a week Table 15: Corresponding measurement indices and frequencies of water at the outlet before treatment (11 in [Fig.1]).

[0129] If the turbidity result is high, the flocculant dosage is increased; if the total iron is high, the flocculant dosage is decreased.

[0130] In at least one embodiment of this disclosure, S5.2.1 is a specific implementation of S5.2 above.

[0131] S5.2.1: monitoring of the fact that the water quality of the ultrafiltration water tank satisfies the corresponding measurement indices of the water at the outlet of the ultrafiltration, where the corresponding measurement indices of the water at the outlet of the ultrafiltration include a temperature range of 5°C to 40°C, SDIi5 <3, turbidity < 0.2 NTU, residual chlorine <0.1 mg / L and pH25 in a range of 4 to 11.

[0132] [Tables 16] Temperature Index, °C sdi15 Turbidity, NTU Residual Chlorine, mg / L pH25 Specification 5~40 <3 <0.2 <0.1 4~11 Method pH meter, thermometer Manual method Scattered light turbidity nephelometry DPD method Electrode method Frequency Once a week Once a week Once a week Once a week Once a week Table 16: Measurement indices and frequencies of water at the outlet of ultrafiltration (16 in [Fig.2]).

[0133] If the turbidity or SDIi5 result is high, the ultrafiltration membrane should be checked for possible damage, or membrane cleaning should be intensified.

[0134] S5.5: Monitoring and adjustment of the inlet water quality of the first module reverse osmosis phase to meet the corresponding measurement indices of the inlet water sampling point of the first reverse osmosis module when the first reverse osmosis module malfunctions during the operating phase of the overall seawater desalination process, the corresponding measurement indices of the inlet water sampling point of the first reverse osmosis module including a temperature range of 5°C to 40°C, SDI15 < 5, residual chloride <0.1 mg / L, pH25 in a range of 4 to 11 and redox potential < 200 mV.

[0135] The corresponding measurement indices and frequencies of the point of sampling of the inlet water of the first stage reverse osmosis module are detailed in Table 17 below.

[0136] [Tables l7] Temperature Index, °C sdi15 Residual Chlorine, mg / L pH25 Redox Potential, mV Specification 5~40 <5 <0.1 4~11 <200 Method pH meter, thermometer Manual Method DPD Method Electrode Method Electrode Method Frequency Measurement in case of anomaly Measurement in case of anomaly Measurement in case of anomaly Measurement in case of anomaly Table 17: Corresponding measurement indices and frequencies of the inlet water sampling point of the first phase reverse osmosis module (22 in [Fig.3]).

[0137] If the redox potential result is high, the dosage of the reducing agent is increased; if the SDIi5 is high, the dosage of the scale inhibitor is increased or the operating conditions of the ultrafiltration are checked; if the residual chlorine is high, the dosage of sodium hypochlorite in seawater is decreased.

[0138] In at least one embodiment of this disclosure, S5.2.2 is a specific implementation of S5.2 above.

[0139] S5.2.2: Monitoring and adjusting the water quality of the first tank freshwater phase to meet the corresponding measurement indices of the sampling point of the first freshwater phase tank when the first freshwater phase tank is abnormal, where the corresponding measurement indices of the sampling point of the first freshwater phase tank include a temperature range of 5°C to 40°C, SDIi5 < 5, residual chlorine <0.1 mg / L and pH25 in a range of 4 to 11.

[0140] The corresponding measurement indices and sampling point frequencies of the first freshwater phase tank are detailed in Table 18 below.

[0141] [Tables l8] Temperature Index, °C sdi15 Residual Chlorine, mg / L pH25 Specification 5~40 <5 <0.1 4~11 Method pH meter, thermometer Manual method DPD method Electrode method Frequency Measurement in case of anomaly Measurement in case of anomaly Measurement in case of anomaly Table 18: Corresponding measurement indices and frequencies of the sampling point of the first phase fresh water tank (30 in [Fig.3]).

[0142] If SDI15 is high, membrane cleaning is reinforced; if residual chlorine is high, sodium hypochlorite dosing in seawater is decreased; if conductivity is high, conductivity at the outlet of each reverse osmosis membrane is checked.

[0143] In at least one embodiment of this disclosure, S5.3.1 is a specific implementation of S5.3 above.

[0144] S5.3.1: Monitoring of the water quality of the industrial water tank and the domestic water tank meets the corresponding measurement indices of the industrial water sampling point, where the corresponding measurement indices of the industrial water sampling point include a temperature between 5°C and 40°C, a total hardness > 40 mg / L, an alkalinity > 40 mg / L, a pH25 between 8.0 and 9.0, and a Langelier index > 0.5.

[0145] The corresponding measurement indices of the industrial water sampling point are detailed in Table 19 below.

[0146] [Tables 19] Temperature Index, °C Water Hardness, mg / L Alkalinity, mg / L pH25 Langelier Index Specification 5-40 >40 >40 8.0-9.0 >0.5 Method pH meter, thermometer Titration method, electrode method Titration method Electrode method Online Frequency Once a week Once a week Once a week Once a week Once a week Table 19: Measurement indices and frequencies of the industrial water sampling point (58 in [Fig.9])

[0147] If the hardness or Langelier index is relatively low, the amount of calcium chloride dosed is increased; if the alkalinity is too low, the amount of sodium bicarbonate and sodium carbonate dosed is increased.

[0148] In at least one embodiment of this disclosure, S5.2.3 is a specific implementation of S5.2 above.

[0149] S5.2.3: Monitoring and adjustment of the fresh water tank water quality of the second phase to respond to the corresponding measurement indices of the sampling point of the second phase freshwater tank when the second phase freshwater tank is abnormal, where the corresponding measurement indices of the point Sampling parameters for the second-phase freshwater tank include a temperature range of 5°C to 40°C, TDS < 50 mg / L, and pH25 in a range of 6.5 to 8.5.

[0150] The corresponding measurement indices and sampling frequencies for the second-phase freshwater tank are detailed in Table 20 below.

[0151] [Tables20] Temperature Index, °C SST, mg / L pH25 Specification 5-40 <50 6.5-8.5 Method pH meter, thermometer Drying Method Electrode Method Frequency Measurement in case of anomaly Measurement in case of anomaly Measurement in case of anomaly Table 20: Corresponding measurement indices and frequencies of the sampling point of the second phase fresh water tank (42 in [Fig.4]).

[0152] If the TDS is high, membrane cleaning is intensified; if residual chlorine is high, the dosage of sodium hypochlorite in seawater is decreased; if conductivity is high, the conductivity at the outlet of each reverse osmosis membrane is checked to identify the damaged membrane component.

[0153] S5.6: Monitoring and adjustment of water quality at the outlet of the cation bed to meet the corresponding measurement indices of the cation bed outlet sampling point when the water at the cation bed outlet is abnormal. The corresponding measurement index of the cation bed outlet sampling point includes: sodium < 3 qg / L.

[0154] [Tables21] Sodium Index, qg / L Specification <3 Method Flame method, electrode method Frequency Measurement in case of anomaly Table 21: Corresponding measurement indices and sampling point frequencies of the cationic bed outlet (44 in [Fig.5]).

[0155] If the sodium content is high, the cation bed must be regenerated.

[0156] S5.7: Monitoring and adjustment of water quality at the outlet of the anion bed for respond to the corresponding measurement indices of the output sampling point of the anionic bed when the water at the outlet of the anionic bed is abnormal, the corresponding measurement indices of the sampling point of the outlet of the anionic bed including a conductivity < 5 qS / cm and a soluble silica < 50 qg / L.

[0157] The corresponding measurement indices of the sampling point of the anionic bed outlet are detailed in Table 22 below.

[0158] [Table 22], Conductivity Index, qS / cm Soluble Silica, qg / L Specification <5 <50 Method Electrode Method Spectrophotometry Method Frequency Measurement in case of anomaly Measurement in case of anomaly Table 22: Corresponding measurement indices and sampling point frequencies of the anionic bed outlet (47 in [Fig.6])

[0159] If the conductivity or soluble silica is high, the anionic bed is regenerated.

[0160] S5.8: Monitoring and adjusting water quality at the outlet of the mixed bed to meet the measurement indices corresponding to the sampling point of the mixed bed outlet when the water at the outlet of the mixed bed is abnormal, the measurement indices corresponding to the sampling point of the mixed bed outlet include chloride ions < 1 qg / L, sulfate radicals < 1 qg / L, conductivity <0.15 qS / cm, TOC <100 qg / L, soluble silica <10 qg / L, pH25 in a range of 6.5 to 8.0 and sodium < 3 qg / L.

[0161] The measurement indices corresponding to the sampling point of the outlet of the mixed bed are detailed in Table 23 below.

[0162] [Table 23]. Chloride ion index, pg / L Tallow radical, pg / L Conductivity, p S / cm TOC, pg / L Soluble silica, pg / L pH25 Sodium, pg / L Specificity <1 <1 <0.15 <100 <10 6.5-8, 0 <3 Frequency Chromatography Chromatography Method Met Method s Met Met nce raphie ioniq raphie ioniq par electrohode u pectropho hode p hode a ue ode Itravi olet tométrie ar éctrode u four à graphite. Frequency Measurement in Measurement in Measurement My Measurement in case of anomaly in case of anomaly in case of anomaly in case of anomalies in case of anomaly in case of anomaly in case of anomaly Table 23: Corresponding measurement indices and sampling point frequencies of the mixed bed outlet (50 in [Fig.7]).

[0163]

[0163] If an index other than pH is relatively high, bed regeneration mixing is necessary.

[0164]

[0164] In at least one embodiment of this disclosure, S5.4.1 is a specific implementation of S5.4 above.

[0165]

[0165] S5.4.1: monitoring that the water quality in the tank is in the demineralized water system satisfies the corresponding measurement indices of the tank sampling point, where the corresponding measurement indices of the tank sampling point include chloride ions < 50 pg / L, sulfate radicals < 50 pg / L, conductivity <1.2 pS / cm, TOC < 500 pg / L, soluble silica < 20 pg / L, and pH25 in a range of 6.5 to 8.0.

[0166]

[0166] [Table 24] Chloride ion index, pg / L Tallow radical, pg / L Conductivity, pS / cm TOC, pg / L Soluble silica, pg / L pH25 Specification <50 <50 <1.2 <500 <20 6.5-8.0 Method Ion chromatography Ion chromatography Electrode method Ultraviolet method Spectrophotometry method Electrode method Frequency Measurement in case of anomaly Measurement in case of anomaly Measurement in case of anomaly Measurement in case of anomaly Measurement in case of anomaly Table 24: Corresponding measurement indices and frequencies of the sampling point of the demineralized water tank (54 in [Fig.8]).

[0167] If bacterial indicators exceed the standard, it is necessary to increase the dose of sodium hypochlorite.

[0168] In the above embodiments of this disclosure, regulations are established for monitoring the water quality of the seawater desalination system to facilitate the arrangement of sampling points during the design phase and to implement scientific monitoring during assembly, commissioning, and operation. Water quality monitoring includes elements such as sampling point selection, index types, and index ranges; and three distinct phases: assembly, commissioning, and operation. This technology provides methods for various elements and phases of water quality monitoring in seawater desalination to ensure that water quality can be effectively controlled.After implementation, the technology can guide water quality monitoring of the seawater desalination system, ensuring the system's safety and cost-effectiveness during commissioning and operation. Furthermore, by establishing a water quality monitoring method for the seawater desalination system based on different water usage scenarios, various water use scenarios are covered. Additionally, by controlling the process of each subsystem, successful initial commissioning and long-term, continuous, and stable operation can be achieved, thus improving risk prevention capabilities, which is primarily reflected in training. references for design, discovery of assembly and commissioning defects, and provision of a guide for operational adjustment.

[0169] It should be noted that the combinations of technical features in the embodiments of this disclosure are not limited to those described in the specific embodiments or examples of this disclosure. All technical features described in this disclosure may be freely combined or associated in any way, unless there is a conflict between them.

[0170] As stated in this disclosure and in the claims, unless the context clearly indicates otherwise, the terms "a", "an", "an", and / or "the" are not limited to singular forms and may also include plural forms. In general, the terms "include" and "include" indicate only that the steps and elements that have been explicitly identified are included, and these steps and elements do not constitute an exhaustive list. The method or device may also include other steps or elements.

[0171] The above description is only a preferred embodiment of this disclosure and is not intended to limit this disclosure. Any modification, equivalent substitution, or improvement made in the spirit and principle of this disclosure shall be included within the scope of protection of this disclosure.

Claims

Demands

1. A method for monitoring the water quality of a seawater desalination system, comprising: monitoring at least one water intake point corresponding to a planned water source to obtain water quality input parameters during a design phase of an overall seawater desalination process;the use of water quality input parameters as design input quantities of the seawater desalination system during the design phase of the overall seawater desalination process, and the monitoring of a plurality of sampling points on the seawater desalination system to satisfy corresponding predefined requirements, the plurality of sampling points being respectively taken from a pretreatment system, an ultrafiltration system, a first-stage reverse osmosis system, a second-stage reverse osmosis system, a cation bed, an anion bed, a mixed bed, a demineralized water tank, and a first-stage freshwater distribution system;monitoring of the chemicals used in the seawater desalination system to meet corresponding predefined requirements during the assembly and commissioning phase and the operational phase of the overall seawater desalination process; carrying out long-term monitoring of the effluent from the pretreatment system, the membrane system, the industrial and domestic water system and the demineralized water system in the seawater desalination system during the assembly and commissioning phase of the overall seawater desalination process, in order to ensure stable operation; and monitoring of the water quality of the effluent from the pretreatment system, the membrane system, the industrial and domestic water system and the demineralized water system in the seawater desalination system during the operational phase of the overall seawater desalination process.

2. The method for monitoring the water quality of the seawater desalination system according to claim 1, the step of monitoring of at least one water intake point corresponding to a planned water source to obtain water quality input parameters in a seawater desalination design phase includes: monitoring of seawater quality under different seasons and tidal levels in the design phase of the entire seawater desalination process to satisfy a first water quality index, provided that the planned water source is seawater, the first water quality index including turbidity, permanganate index, total iron, pH, temperature, anionic surfactants, sodium ions, chloride ions, sulfate radicals, hardness, calcium ions, magnesium ions, nitrate radicals, manganese, copper and algae;or the monitoring of hot wastewater quality in the design phase of the entire seawater desalination process to satisfy a second water quality index, provided that the intended water source is hot wastewater, the second water quality index comprising turbidity, permanganate index, total iron, pH, temperature, anionic surfactants, sodium ions, chloride ions, sulfate radicals, hardness, calcium ions, magnesium ions, nitrate radicals, manganese, copper, algae, total phosphorus, ammonia nitrogen and petroleum.;

3. The method for monitoring the water quality of the seawater desalination system according to claim 2, wherein, after the step of monitoring the chemicals used in the seawater desalination system to meet the corresponding predefined requirements during the design phase of the entire seawater desalination process, the method further comprises: continued monitoring to verify whether the first water quality index or the second water quality index does not exceed a predefined value during the assembly and commissioning phase of the entire seawater desalination process; and evaluation to determine whether the seawater desalination system is capable of withstanding the first water quality index. water or the second water quality index exceeds the predefined value; and upgrading the seawater desalination system when the seawater desalination system is unable to withstand the pressure.

4. The method for monitoring the water quality of the seawater desalination system according to claim 1, wherein the plurality of sampling points comprises a water source inlet, a dosing mixer outlet, a settling tank outlet, a clear water tank, an ultrafiltration module inlet, an ultrafiltration module outlet, a sampling point for the ultrafiltration-produced water tank, a dedicated sampling point for the SDIi5 of the ultrafiltration-produced water, a sampling point for the inlet water of the first-stage reverse osmosis module, a water outlet from the first-stage reverse osmosis module, a single-membrane outlet from the first-stage reverse osmosis module, a sampling point for a first-stage freshwater tank, a dedicated sampling point for the SDIi5 of the first-stage freshwater,a water inlet from a second-phase reverse osmosis module, a water outlet from the second-phase reverse osmosis module, an outlet from a single membrane of the second-phase reverse osmosis module, a sampling point from a second-phase freshwater tank, a cation bed outlet, an anion bed outlet, a mixed bed outlet, a sampling point from a demineralized water tank, a sampling point from an industrial water tank, and a sampling point from a domestic water tank.

5. The method for monitoring the water quality of the seawater desalination system according to claim 1, further comprising: conducting efficacy verification tests on different flocculants to determine an optimal flocculant during the design phase of the entire seawater desalination process; and conducting further simulation tests on the dosages of flocculants and coagulation aids for the pretreatment system during a flocculation and sedimentation phase in the assembly and commissioning phase of the entire process

6. seawater desalination, and the determination of an optimal dosage concentration by testing different concentrations of flocculants and coagulation adjuvants. The method for monitoring the water quality of the seawater desalination system according to claim 1, the step of performing long-term monitoring of the outlet water of the pretreatment system, the membrane system, the industrial and domestic water system and the demineralized water system in the seawater desalination system during the assembly and commissioning phase of the entire seawater desalination process, in order to ensure stable operation, comprises: measure residual chlorine at the outlets of a dosing mixer and a settling tank of the pretreatment system during the assembly and commissioning phase of the entire seawater desalination process, evaluate the effect of an oxidizing agent and adjust a dosing concentration of the oxidizing agent according to the effect of the oxidizing agent; sample the clear water tank daily in the pretreatment system and regularly inspect the upper water in the clear water tank; calculate the Langelier index before and after the use of a scaling inhibitor for the membrane system, obtain the effect of a current concentration of the scaling inhibitor and adjust a dosage concentration of the scaling inhibitor according to the effect of the current concentration of the scaling inhibitor; measure the redox potential before and after the use of a reducing agent for the membrane system, obtain the effect of a current concentration of the reducing agent and adjust a dosage concentration of the reducing agent according to the effect of the current concentration of the reducing agent; measure the organic matter content in a drainage after assembly of the ultrafiltration membranes and reverse osmosis membranes and first filling of water for the membrane system, ensuring that the organic matter content does not exceed the total organic carbon of the incoming water; inspect, for the membrane system, the inlet water and the outlet water of each ultrafiltration membrane when the water quality in the ultrafiltered water tank is abnormal; and further inspect the pretreatment system when an anomaly is indicated by the quality of the incoming water; guide the dosage of the corresponding chemicals for the industrial and domestic water system by measuring alkalinity, hardness and residual chlorine in an industrial water tank and a domestic water tank; regularly inspect the water quality in a demineralized water tank, a cationic bed outlet, an anionic bed outlet and a mixed bed outlet for the demineralized water system; perform a further inspection before reuse when the demineralized water tank has been inactive for more than 10 days; monitor whether the seawater inlet to the pretreatment system meets the corresponding measurement indices of the water source inlet during the assembly and commissioning phase of the entire seawater desalination process, the corresponding measurement indices of the water source inlet including a temperature range of 5°C to 40°C; monitor whether an outlet from the settling basin in the pretreatment system meets the corresponding measurement indices of the settling basin outlet during the assembly and commissioning phase of the entire seawater desalination process, the corresponding measurement indices including a temperature range of 5°C to 40°C and a turbidity of less than 5 NTU; monitor whether the water at the outlet of the membrane system meets the corresponding measurement indices, the indices including a temperature range from 5°C to 40°C, SDIi5 <3, turbidity < 0.2 NTU and pH25 in a range from 4 to 11; monitor whether the inlet water of a first-stage reverse osmosis module in the membrane system meets the corresponding indices at a sampling point, the indices including a range from 5°C to 40°C, SDIi5 <5, residual chlorine <0.1 mg / L, pH25 in a range from 4 to 11, and redox potential <200 mV; monitor whether the quality at a sampling point of a first-stage freshwater tank in the membrane system meets the corresponding indices, the indices including a range from

7. 5°C to 40°C, SDI15 <5, residual chlorine <0.1 mg / L, pH25 in a range of 4 to 11 and conductivity < 1000 qS / cm; monitor whether the quality at a sampling point of a freshwater tank in the second phase in the membrane system meets the corresponding indices, the indices including a range from 5°C to 40°C, TDS <50 mg / L and pH25 in a range from 6.5 to 8.5; monitor whether the quality at a sampling point of a cationic bed outlet meets the corresponding indices, the indices including sodium less than or equal to 3 qg / L; monitor whether the quality at a sampling point of an anionic bed outlet meets the corresponding indices, the indices including conductivity < 5 qS / cm and soluble silica <50 qg / L; monitor whether the quality at a sampling point of a mixed bed outlet meets the corresponding indices, the indices including chloride ion < 1 qg / L, sulfate radical < 1 qg / L, conductivity <0.15 qS / cm, TOC < 100 qg / L, soluble silica < 10 qg / L, pH25 in a range of 6.5-8.0 and sodium < 3 qg / L; monitor whether the quality at a sampling point in a demineralized water tank meets the corresponding indices, the indices including chloride ion < 50 qg / L, sulfate radical < 50 qg / L, conductivity < 1.2 qS / cm, total organic carbon (TOC) < 500 qg / L, soluble silica < 20 qg / L and pH25 in a range of 6.5 to 8.0; monitor whether industrial water meets the corresponding indices at a sampling point, the indices including temperature in a range of 5°C to 40°C, total hardness > 40 mg / L, alkalinity > 40 mg / L, pH25 in a range of 8.0 to 9.0 and Langelier index > 0.5; and to monitor whether domestic water meets the indices corresponding to a sampling point, the indices including residual chlorine in a range from 0.3 mg / L to 2.0 mg / L, permanganate index < 3 mg / L, turbidity < 1 NTU, pH25 in a range from 6.0 to 9.0, total bacterial count < 100 and total coliform group = 0 / 100 mL. The method for monitoring the water quality of the seawater desalination system according to claim 1, wherein the step of monitoring the water quality of the water at the outlet of the pretreatment system, the membrane system, the water system industrial and domestic water, and the demineralized water system in the seawater desalination system during the operational phase of the entire seawater desalination process includes: periodically measuring the water quality of the clear water tank in the pretreatment system during the operational phase of the entire seawater desalination process, and periodically checking the top of the clear water tank; periodically measuring the water quality of the ultrafiltration water tank, the first fresh water tank and the second fresh water tank; periodically inspecting the water quality of the industrial water tank and the domestic water tank in the industrial and domestic water system; and periodically inspecting the water quality of the demineralized water tank in the demineralized water system.

8. The method for monitoring the water quality of the seawater desalination system according to claim 7, wherein the step of periodically measuring the water quality of the clear water tank in the pretreatment system during the operating phase of the entire seawater desalination process, and of periodically monitoring the upper water of the clear water tank, comprises: monitoring whether water at the outlet of the pretreatment system meets the corresponding measurement indices of the water at the outlet of the pretreatment, where the corresponding measurement indices of the water at the outlet of the pretreatment include a temperature range of 5°C to 40°C and a turbidity <1 NTU;the periodic measurement step of water quality of the ultrafiltration water tank, the first fresh water tank and the second fresh water tank in the membrane system includes: monitoring whether the water quality of the ultrafiltration water tank meets the corresponding measurement indices of the water at the outlet of the ultrafiltration, where the corresponding measurement indices of the water at the outlet of the ultrafiltration include a temperature range of 5°C to 40°C, SDIi5 <3, turbidity < 0.2 NTU, residual chlorine <0.1 mg / L, and pH25 in a range of 4 to 11; monitoring and adjusting the quality of the first-phase freshwater tank when the first-phase freshwater tank is abnormal to meet the corresponding measurement indices of a sampling point of the first-phase freshwater tank, where the corresponding measurement indices of the sampling point of the first-phase freshwater tank include a temperature range of 5°C to 40°C, SDI<5, residual chlorine <0.1 mg / L, and pH25 in a range of 4 to 11; monitoring and adjusting the quality of second-phase freshwater tank water when the second-phase freshwater tank is abnormal to meet the corresponding measurement indices of a sampling point of the second-phase freshwater tank, where the corresponding measurement indices of the sampling point of the second-phase freshwater tank include a temperature range of 5°C to 40°C, TDS<50 mg / L, and pH25 in a range of 6.5 to 8.5; The periodic inspection stage of water quality in industrial and domestic water tanks within the industrial and domestic water system includes: Monitoring whether the water quality in the industrial and domestic water system meets the corresponding measurement indices of a sampling point for industrial water, where the corresponding measurement indices of the sampling point for industrial water include a temperature in the range of 5°C to 40°C, total hardness > 40 mg / L, alkalinity > 40 mg / L, pH25 in the range of 8.0 to 9.0, and Langelier index > 0.5; and the periodic inspection step of water quality in the demineralized water system includes: monitoring whether the water quality in the demineralized water system meets the corresponding measurement indices of a sampling point for the demineralized water tank, where the corresponding measurement indices of the sampling point for the demineralized water tank include chloride ion < 50 qg / L, sulfate radical < 50 qg / L, conductivity <1.2 qS / cm, TOC < 500 qg / L, soluble silica < 20 qg / L, and pH25 in a range of 6.5 to 8.

0.

9. The method of monitoring the water quality of the seawater desalination system according to claim 1, further comprising: monitoring and adjusting the inlet water quality of the first-stage reverse osmosis module to meet the corresponding measurement indices of a sampling point of the inlet water of the first-stage reverse osmosis module when the first-stage reverse osmosis module is abnormal during the operating phase of the entire seawater desalination process, the corresponding measurement indices of the sampling point of the inlet water of the first-stage reverse osmosis module comprising a temperature range of 5°C to 40°C, SDIi5 < 5, residual chlorine <0.1 mg / L, pH25 in a range of 4 to 11, and redox potential < 200 mV;monitoring and adjusting water quality at the outlet of the cationic bed to meet the corresponding measurement indices of a sampling point at the outlet of the cationic bed when the water at the outlet of the cationic bed is abnormal, the corresponding measurement index of the sampling point at the outlet of the cationic bed including sodium < 3 qg / L; monitoring and adjusting water quality at the outlet of the anionic bed to meet the corresponding measurement indices of a sampling point at the outlet of the anionic bed when the water at the outlet of the anionic bed is abnormal, the corresponding measurement indices of the sampling point at the outlet of the anionic bed including conductivity < 5 qS / cm and soluble silica <50 qg / L;and the monitoring and adjustment of water quality at the outlet of the mixed bed to meet the corresponding measurement indices of a sampling point of a mixed bed outlet when the water at the outlet of the mixed bed is abnormal, the corresponding measurement indices of the sampling point of the mixed bed outlet including chloride ion < 1 qg / L, sulfate radical < 1 qg / L, conductivity < 0.15 qS / cm, TOC < 100 qg / L, soluble silica < 10 qg / L, pH25 in a range of 6.5-8.0 and sodium < 3 qg / L.;

10. The method for monitoring the water quality of the seawater desalination system according to any one of claims 1 to 9, wherein the step of monitoring chemicals used in the seawater desalination system to meet the corresponding predefined requirements during the design phase of the entire seawater desalination process also includes: sampling and monitoring of temporary loading of tank trucks for the seawater desalination system during the design phase of the entire seawater desalination process, in order to ensure the quality of chemicals entering a plant; monitoring that the concentration of alkaline solution prepared in an alkaline solution dosing tank is within a normal range; monitoring that the concentration of acid solution prepared in an acid solution dosing tank is within a normal range; monitoring that a concentration of reducing agent prepared in a reducing agent dosing tank is within a normal range; monitoring that a concentration of oxidizing agent prepared in an oxidizing agent dosing tank is within a normal range; monitoring that a concentration of scale inhibitor prepared in a scale inhibitor dosing tank is within a normal range; monitoring to ensure that a flocculant concentration prepared in a flocculant dosing tank is within a normal range; and monitoring that a concentration of coagulation adjuvant prepared in a coagulation adjuvant dosing cuvette is within a normal range.

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