Method and system for controlling hydrophobic conditions and fouling in water-intensive processes

Abstract

In the water treatment system, during the pretreatment process (1) which includes coagulation, flocculation (10), and separation (18, 19), pretreatment chemicals (14) are added to the water stream (5C) to reduce the amount of dissolved and / or particulate matter in the water stream. Hydrophobic conditions in the water stream are monitored (12) upstream (15C) or downstream (15A, 15B) of the addition of the pretreatment chemicals. The metered addition (11) of the pretreatment chemicals (14) to the water stream is controlled (13) based on the monitored hydrophobic conditions. This minimizes membrane fouling in the subsequent membrane filtration stage (3).

Description

[0001] This application is a divisional application of Chinese patent application filed on October 6, 2017, with application number 201780068973.0 and entitled "Method and System for Controlling Hydrophobic Conditions and Scaling in Water-Intensive Processes". Technical Field

[0002] This invention relates to water treatment systems, and more particularly to water treatment systems having a water pretreatment process, particularly membrane filtration or reverse osmosis, prior to one or more subsequent water treatment steps. Furthermore, this invention relates to water treatment systems with a pretreatment process to reduce or prevent scaling on surfaces in subsequent processes using water from the pretreatment process. Background Technology

[0003] The use of membrane technologies such as microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), and reverse osmosis (RO) is becoming increasingly important in drinking water and wastewater treatment. Membranes provide a physical barrier that allows only materials of a certain size, shape, or characteristic to pass through, effectively removing solids, viruses, bacteria, and other unwanted molecules. Membranes are manufactured in various structures, including hollow fiber, spiral, and tubular.

[0004] Water, such as wastewater and raw water, especially surface water, contains impurities that can affect the operation of processes such as membrane processes. Organic compounds and mineral salts present in the water can form scale on equipment surfaces, such as membrane surfaces, which can reduce the overall efficiency of the water treatment plant. Several types of scaling exist: including inorganic scaling or deposits, colloidal scaling, organic scaling, and biological scaling. Therefore, water treatment processes, such as membrane processes, may require pretreatment steps to reduce the amount of organic matter and particulate matter in the feed water.

[0005] Without pretreatment to reduce the amount of organic matter and particulate matter, water, such as wastewater and raw water, especially surface water, contains impurities that can cause scaling on surfaces in contact with the water. Scaling typically becomes a problem on the surfaces of pipes, instruments, heat exchangers, cooling water systems, and splash zones.

[0006] Coagulation is typically used in pretreatment steps to remove most organic and inorganic substances that contribute to scaling. To track coagulation performance, key parameters need to be monitored to ensure the pretreatment is adequate and effective. However, the most common issues are inappropriate adjustments to the coagulant (over- or under-dosing) and operating conditions that degrade coagulation performance. To mitigate the effects of excessive / low dosages of one or more coagulants, a system is needed to control the dosage of coagulants and / or flocculants.

[0007] Various methods exist for implementing dosage control of coagulants and / or flocculants. A flow current detector (SCD) operates by fixing charged particles and measuring the current generated within the water flow due to these particles; that is, the flow current. Water is drawn in from a sampling point, and electrodes are used to detect the potential difference between the fixed and moving components.

[0008] Another approach is to use the zeta (ζ) potential, which provides a measurable value for monitoring optimal water clarification. At near-zero ζ potentials, the system is unstable and highly prone to aggregation. Therefore, monitoring the ζ potential of the water treatment stream attempts to provide a way to maintain optimal flocculation conditions.

[0009] Another approach is to adjust the amount of coagulant added based on pH.

[0010] Conventional systems are inaccurate and do not provide sufficient information for accurate control of chemical treatments. The water industry is keen to access online measurements and is moving towards automated, more accurate control of coagulants and / or flocculants. Furthermore, there is a desire for more effective measurement of the selection and / or dosage of flocculants and / or coagulants in water treatment processes.

[0011] US 2013078730 A1 discloses a method for detecting the presence and amount of contaminants such as grease in wastewater.

[0012] WO 2012111402 A discloses a pretreatment apparatus for pretreatment to remove impurities by filtering water containing solutes.

[0013] JP 2007245078 A discloses a water treatment system having a flocculation process unit for adding a coagulant to natural water and causing the coagulant to aggregate, and a membrane separation unit for filtering the flocculated water.

[0014] WO 2015075319 A1 discloses a method of breaking a sample into a group of particles and using fluorescence or absorbance measurements to determine the particle size and amount of hydrophobic particles. Summary of the Invention

[0015] The object of the present invention is to provide a method for controlling water treatment in a manner that overcomes at least some of the problems in the present methods.

[0016] Another object of the present invention is to provide a method for controlling the water treatment process in a manner that can prevent or reduce scaling in subsequent water treatment steps, particularly in membrane filtration.

[0017] Another object of the present invention is to provide a method for controlling a water treatment process in a manner that reduces or prevents scaling on the surfaces of process equipment in one or more subsequent processes using water from a pretreatment process. An aspect of the invention is the use of the method, control system, and hydrophobicity monitoring unit in controlling a water treatment process, according to the appended independent claims. Embodiments of the invention are detailed in the dependent claims.

[0018] One aspect of the present invention is a method for controlling a water treatment process, the method comprising:

[0019] In a pretreatment process that includes a coagulation step and / or a flocculation step and at least one separation step, at least one pretreatment chemical is added to the water stream to reduce the amount of dissolved and / or particulate matter in the water stream.

[0020] Monitoring the hydrophobic conditions in the upstream and / or downstream water flow where at least one pretreatment chemical is added, and

[0021] The metered addition of the at least one pretreatment chemical to the water stream is controlled based on at least monitored hydrophobic conditions.

[0022] In one embodiment, the at least one separation step includes one or more of a flotation step, a sedimentation step, and a filtration step.

[0023] In one embodiment, the control includes controlling the metered addition of the at least one pretreatment chemical such that the hydrophobic conditions in the water flow are shifted or maintained below or at a target hydrophobic condition.

[0024] In one implementation, the monitoring includes classifying a sample of the water flow into two or more particle groups based on particle size and / or particle mass.

[0025] In one implementation, the monitored and / or target hydrophobic conditions include one or more of the following:

[0026] i) At least a certain particle size and their hydrophobicity

[0027] ii) Hydrophobicity of at least a certain particle size

[0028] iii) The quantity or count of hydrophobic particles of a certain size

[0029] iv) Hydrophobic distribution of particles

[0030] v) The overall hydrophobicity of water flow,

[0031] vi) Total particle count,

[0032] vii) Particle count of one or more particle groups,

[0033] viii) Particle size distribution.

[0034] ix) Hydrophobicity of one or more particle groups.

[0035] In one embodiment, the method further includes membrane filtration of the pretreated water stream downstream of the pretreatment process, wherein the control of metering the addition of the at least one pretreatment chemical is configured to reduce membrane fouling in the membrane filtration.

[0036] In one embodiment, the control of the metered addition of the at least one pretreatment chemical includes one or more of the following:

[0037] i) Feedback-based control based on samples extracted from the water stream downstream of the addition of at least one pretreatment chemical, preferably after the at least one separation step.

[0038] ii) Feedforward control based on samples extracted from upstream water flow containing at least one pretreatment chemical, and

[0039] iii) Feedforward control of the first of the at least one pretreatment chemical and feedback control of the second of the at least one pretreatment chemical.

[0040] In one implementation, the monitored and / or target hydrophobic conditions include:

[0041] Hydrophobicity was determined based on fluorescence measurements, and

[0042] The amount or count of particles is determined based on optical measurements, such as light scattering measurements or turbidity measurements.

[0043] In one implementation scheme

[0044] Based on particle size and / or mass, the water sample is divided into two or more particle groups.

[0045] Before or during grading, the samples are stained with fluorescent dyes, preferably Nile Red dyes.

[0046] Fluorescence intensity data over time were measured for each cohort of stained samples.

[0047] The hydrophobicity of each group is calculated from the fluorescence intensity data by integrating the measured fluorescence intensity over time.

[0048] In one embodiment, the method includes membrane filtration of a pretreated water stream downstream of a pretreatment process, and cleaning of the membrane filtration controlled, initiated, or rearranged based on hydrophobic conditions monitored by the water stream, the cleaning preferably including metered addition of at least one chemical cleaning agent.

[0049] Another aspect of the present invention is a control system for implementing a control method according to an embodiment of the present invention, the control system comprising a metering addition unit configured to add at least one pretreatment chemical to a water flow, an online monitoring unit configured to monitor the hydrophobic conditions of the water flow, and a control unit configured to control the metering addition unit based on hydrophobic condition data provided by the online monitoring unit.

[0050] In one implementation, the online monitoring unit includes optical detectors, such as fluorescence detectors and light scattering detectors or turbidity detectors.

[0051] In one embodiment, the system further includes a membrane cleaning system controlled based on hydrophobic condition data provided by an online monitoring unit.

[0052] Another aspect of the invention is the use of an online hydrophobicity monitoring unit in controlling water treatment processes.

[0053] Another aspect of the invention is the use of a method according to an embodiment of the invention to prevent or reduce scaling on surfaces such as pipes, heat exchangers, instruments, cooling water systems, or other underwater surfaces and splash zones in subsequent water treatment steps, such as membrane filtration, or in one or more subsequent processes using water from the pretreatment process.

[0054] Another aspect of the invention is the use of a method according to an embodiment of the invention to optimize hydrophobic conditions on surfaces such as pipes, heat exchangers, instruments, cooling water systems, other underwater surfaces, and splash zones in subsequent water treatment steps, such as membrane filtration, or in one or more subsequent processes using water from a pretreatment process.

[0055] In the implementation plan, process steps include process steps in the pulp and paper industry, food and beverage industry, mining industry, or petroleum industry. Attached Figure Description

[0056] Exemplary embodiments of the invention will be described below with reference to the accompanying drawings, in which:

[0057] Figure 1 This is a schematic block diagram of an exemplary water treatment system;

[0058] Figure 2 This is an explanation Figure 1 A flowchart illustrating an exemplary operation of a water treatment system;

[0059] Figure 3 This is a flowchart illustrating an exemplary control of pretreatment chemicals based on particle size and hydrophobicity in a water treatment system;

[0060] Figure 4The samples are shown before and after grading;

[0061] Figure 5 Illustrative fluorescence data for the three fractions F1, F2, and F3 are shown;

[0062] Figure 6 Examples of scattering signals and fluorescence data are shown;

[0063] Figure 7A and 7B These are bar graphs illustrating the count and size of hydrophobic particles in samples at different measurement points during the water treatment process in operation.

[0064] Figure 7C and 7D The changes in the count of hydrophobic particles in one type of surface water and several different types of surface water were illustrated using different pretreatment chemicals.

[0065] Figure 8 Examples illustrating the metered addition of pretreatment chemicals (milligrams per liter of water) as the count of hydrophobic particles varies; and

[0066] Figure 9 This is a schematic block diagram of a monitoring unit according to an exemplary implementation. Detailed Implementation

[0067] The embodiments of the present invention can be used to control water pretreatment before membrane filtration in a water treatment system.

[0068] The embodiments of the present invention can also be used to control water pretreatment before other water treatment steps.

[0069] Embodiments of the present invention can be used to prevent or reduce scaling in subsequent water treatment steps, such as membrane filtration.

[0070] The embodiments of the present invention can be used to optimize hydrophobic conditions in subsequent water treatment steps, such as membrane filtration.

[0071] Embodiments of the present invention are not limited to water treatment systems and scaling in membrane filtration. Embodiments of the present invention can also be used to control water pretreatment before the use of pretreated water in any subsequent (follow-up) processes where scaling may occur.

[0072] Embodiments of the present invention can be used to prevent or reduce scaling on surfaces in one or more subsequent process steps using water from a pretreatment process. Surfaces where scaling can be prevented or reduced may include, for example, surfaces of pipes, heat exchangers, instruments, cooling water systems, other underwater surfaces, and splash zones. One or more process steps may include, for example, process steps in the pulp and paper industry, food and beverage industry, mining industry, or petroleum industry.

[0073] Embodiments of the present invention can be used to optimize hydrophobic conditions on surfaces in one or more subsequent process steps using water from a pretreatment process. Surfaces for which hydrophobic conditions are optimized may include, for example, surfaces of pipes, heat exchangers, instruments, cooling water systems, other underwater surfaces, and splash zones. One or more process steps may include, for example, process steps in the pulp and paper industry, food and beverage industry, mining industry, or petroleum industry.

[0074] An example of a water treatment system is shown schematically. Figure 1 Water: Raw water, such as surface water, industrial water, wastewater, brine or brackish water, or any other type of water supply, may first undergo a preliminary water treatment process (any physical, chemical, or mechanical process) before undergoing the main treatment process. For example, during preliminary treatment, screens or screen filters may typically be used to remove rocks, branches, leaves, and other debris, or a pre-sedimentation stage may be used to settle sand, gravel, and pebbles from the raw water.

[0075] In the main treatment process, the first step can be a pretreatment process 1, which reduces the amount of dissolved and / or particulate matter in the water flow 5C, such as raw water or wastewater, which may affect the performance of the subsequent membrane filtration stage 3, for example, by forming scale on the membrane surface. Particulate matter can be colloidal particles and / or suspended particles. Dissolved and particulate matter can each contain organic, inorganic, or both. Membrane filtration 3 can include one or more of microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), reverse osmosis (RO), forward osmosis, membrane contactors, and membrane distillation. The membrane provides a physical barrier that allows only materials up to a certain size, shape, or characteristic to pass through and effectively removes solids, viruses, bacteria, and other unwanted molecules. Membrane filters are commercially available in various configurations, including hollow fiber, spiral, and tubular. It should be understood that the specific implementation of membrane filtration is not relevant to the embodiments of the present invention. An additional water treatment stage 4 may exist before or after membrane filtration 3, after which purified water 7 is obtained. In one embodiment, membrane filtration step 3 is not included in the water treatment process. In yet another implementation, there are no additional water treatment steps following the pretreatment process.

[0076] In the implementation scheme, the process following pretreatment process 1 can be any process step with surfaces on which scaling may occur, such as process steps in the pulp and paper industry, food and beverage industry, mining industry, or oil industry, rather than membrane filtration 3. The same principles described below with respect to subsequent membrane filtration 3 also apply to other types of subsequent process steps or stages.

[0077] Pretreatment 1 ensures the efficiency of subsequent membrane filtration 3. Dissolved and / or particulate matter must be removed and the water pretreated to prevent scaling from affecting the membrane. Keeping the membrane surface clean and free from organic and inorganic scaling is critical, as scaling can lead to a significant decrease in flux and desalination rate, and eventually complete shutdown, consuming time and labor to clean the membrane. A common pretreatment process step in membrane filtration is coagulation or flocculation 10 or a combination thereof. Coagulation can involve the rapid mixing of a coagulant and water (e.g., using...) Figure 1 (A mixing device not shown), and coagulation may be additionally associated with flocculation processes / stages and / or separation stages 18 such as flotation, sedimentation, filtration. Coagulation and / or flocculation steps may also be carried out in piping. Therefore, the coagulation and / or flocculation unit where coagulation and / or flocculation occurs may be, for example, a pipe. Therefore, coagulation and / or flocculation may be inline coagulation and / or flocculation. In this case, unit / step 18 may preferably not be included; and preferably only one separation unit, typically a filter, such as a sand filter, is sufficient to remove flocs. Dense flocs are formed during the flocculation stage. The separation stage may remove suspended matter, which may include one or more of or consist of: flocs precipitated from the raw water, organic matter, microorganisms, algae, sludge, iron, and manganese. If the separation step is a sedimentation step, sludge accumulated at the bottom of the tank or basin may be pumped or scraped off for final disposal. Separation may be carried out in one or more stages, such as separation stages 18 and 19. The final separation stage 19 can be a sand filter, etc., in which residual suspended or coagulated material is filtered out as water passes through a bed of granular material typically composed of layers of sand, gravel, coal, garnet, or related substances. It should be understood that the specific implementation of the coagulation or flocculation process and any potentially associated water pretreatment processes is not relevant to the embodiments of the present invention.

[0078] The main purpose of the coagulation process 10 is to precipitate the dissolved compounds and aggregate small particles into larger particles. For example, pretreatment chemicals 14, such as coagulants and / or flocculants, are added to the water flow 5C (from the raw water) via the pretreatment chemical metering and addition unit 11. Figure 2 (Step 20 in the process). Pretreatment chemicals 14 cause small particles to agglomerate (coagulate), and even smaller particle clumps can further form larger groups called "flocculations". The flocs / suspended solids can be separated by, for example, flotation, sedimentation and / or filtration.

[0079] Coagulants or flocculants include or may be selected from salts of monovalent or polyvalent cations such as sodium, calcium, magnesium, iron, and aluminum, or anionic, nonionic, and cationic polyelectrolytes, natural products such as starch, semi-synthetic polymers such as cationic starch, and synthetic polymers such as acrylic polymers, polyamines, polyethylene oxide and allyl polymers, or mixtures thereof.

[0080] Coagulants are typically inorganic (anionic / cationic) or organic (polyelectrolyte) chemicals that neutralize (destabilize) the negative or positive surface charge of impurities such as dissolved substances and colloidal particles.

[0081] Flocculation, for example, refers to the action of polymers bridging or acting as a patchwork between suspended particles. Flocculants can promote the formation of flocs. Flocculants can be inorganic polymers (such as activated silica), natural polymers (starch, alginate), or synthetic polymers.

[0082] However, the most common improper adjustments to pretreatment chemicals, such as coagulants (overdosing or underdosing), and operating conditions degrade coagulation performance. To mitigate the effects of overdosing or underdosing pretreatment chemicals, such as one or more coagulants, metered addition of pretreatment chemicals is necessary. Figure 2 The system in step 20). The water stream processed with pretreatment chemicals in condensation stage 10 ( Figure 2 Step 22).

[0083] exist Figure 1 In the exemplary pretreatment process 1 shown, a monitoring unit 12 is provided to monitor one or more parameters of the (pretreated) water flow 5A and / or 5B downstream of the flocculation / coagulation 10. Figure 2 (Step 24). For example, water samples or sample streams 15A and / or 15B can be extracted from water streams 5A or 5B respectively and input to monitoring unit 12. In another exemplary embodiment, water samples or water sample streams 15C can be extracted from water stream 5C before pretreatment process 1 or flocculation / coagulation stage 10. In yet another embodiment, samples can be extracted from the water streams after flocculation / coagulation step 10 and before subsequent separation step 18. Furthermore, controller 13 (separate from or integrated with monitoring unit 12) can control the dosage of one or more pretreatment chemicals from pretreatment chemical metering unit 11, more specifically, based on monitoring results 16 of monitoring unit 12. Figure 2 (Step 26). As discussed above, a flowing current detector (SCD), a Zeta (ζ) potential detector, and a pH sensor have been proposed for implementing monitoring unit 12 in existing systems. These approaches have various drawbacks.

[0084] In an embodiment of the invention, the monitoring unit 12 monitors hydrophobic particles in the (pretreated) water flow 5A and / or 5B downstream of condensation 10 (before membrane filtration 3) and / or the (original) water flow 5C upstream. Figure 3 In step 32), and based on the monitoring and control of at least hydrophobic particles, the dosage of one or more pretreatment chemicals 14 is controlled. Figure 3 Step 34).

[0085] In an embodiment of the invention, a monitoring unit 12 monitors at least a certain particle size and their hydrophobicity in the pretreated raw water 5A or 5B downstream of condensation 10 and / or the raw water 5C upstream of condensation 10, and controls the dosage of one or more pretreatment chemicals 14 based on the at least monitored particle size and hydrophobicity.

[0086] In an embodiment of the invention, the monitoring unit 12 monitors the count of hydrophobic particles (preferably particles of a certain size and hydrophobicity) in the pretreated water 5A or 5B downstream of the condensation 10 (before the membrane filtration 3) and / or the raw water 5C upstream, and controls the dosage of one or more pretreatment chemicals 14 based on the count of hydrophobic particles.

[0087] In an embodiment of the invention, the dosage of one or more pretreatment chemicals 14 is controlled based on the monitoring of at least hydrophobic particles in order to reduce membrane fouling in the membrane filtration 3.

[0088] Compared to existing control methods, such as those using flowing current or zeta potential, this technology enables more reliable and accurate pretreatment of feedwater. It also enables more reliable and accurate control of membrane fouling or other post-treatment of water. Post-treatment can be, for example, microfiltration (MF), ultrafiltration (UF), nanofiltration (NF), reverse osmosis (RO), or tertiary flotation. Furthermore, more reliable and accurate methods are used to control scaling on surfaces in subsequent process steps utilizing pretreated water. Such surfaces include pipes, instruments, heat exchangers, cooling water systems, or other underwater surfaces and splash zones. Pretreated water is typically used in industrial processes such as the pulp and paper industry, the food and beverage industry, and the mining and petroleum industries. Information about hydrophobic particles is more reliable and closer to the actual conditions on water treatment surfaces, such as membrane surfaces or other process equipment surfaces. Most organic matter and particles (colloids and suspended solids) are hydrophobic, most membranes have hydrophobic surfaces, and hydrophobic-hydrophobic interactions between hydrophobic particles and membrane surfaces cause membrane fouling. In addition, organic matter, especially hydrophobic particles, tends to form scale on various types of surfaces.

[0089] In an embodiment of the present invention, the hydrophobicity of a certain particle size is determined by fluorescence measurement based on a certain particle size.

[0090] In embodiments of the invention, the monitoring includes monitoring samples extracted from water downstream and / or upstream of the condensation point. The samples may include substantially continuous sample streams or individual samples extracted sequentially, such as at predetermined intervals. Individual samples may be batch samples or “plug samples” extracted using an automated sampling device, having a predetermined size such as a few milliliters to tens of milliliters, preferably about 10 milliliters.

[0091] In embodiments of the invention, different groups of particles in a water flow are distinguished or separated from each other. For example, suspended materials in pretreated raw water can be separated or classified into two or more “fractions” based on particle mass and / or size. For example, classification can be performed by varying the flow rate of water from a pump upstream of the sample to be classified, where the lightest particles emerge first and the heaviest particles emerge last. An example of classification is the method described in WO 2013 / 175007 A1. As an example, Figure 4 The images illustrate the samples before and after classification. Unclassified sample 41 contains a mixture of particles of different sizes. Heavier particles tend to sink, as indicated by the downward arrows through 41. In flow-classified sample 42, the particles are separated into (at least) three particle groups F1, F2, and F3, with the lightest particle F1 being the first and the heaviest F3 being the last. Therefore, the different particle groups F1, F2, and F3 leave the classifier at different times, thus separating the groups in a timely manner. The time required for the groups to leave the classifier can be referred to as the retention time of the group. It can be seen that there is horizontal and vertical separation of the particle groups, with the vertical difference due to differences in particle weight.

[0092] In embodiments of the invention, a sample containing particles may be mixed with a fluorescent dye, also known as a fluorescent probe. This particular type of dye is absorbed only by hydrophobic substances. This process is commonly referred to as sample staining. Staining of the sample or sample particles may be performed before or during grading, or after grading, and before one or more measurements. A predetermined amount of fluorescent dye is added to the sample. The amount of staining agent may be, for example, about 10 to 100 microliters per 1 milliliter of sample, preferably about 40 microliters. A very suitable fluorescent dye that can be used is Nile Red.

[0093] In embodiments of the invention, prior to the monitoring step, for measurement purposes, fluorescence intensity data over time is measured and recorded for samples separated or fractionated into two or more particle groups or fractions. The measured fluorescence data can exist as a fluorescence intensity curve. The fluorescence data is used to calculate hydrophobicity. When a hydrophobic dye, such as Nile Red, is added to the sample, the fluorescence intensity is directly related to the hydrophobicity of the sample fraction. Hydrophobicity can be determined as the integral area under the fluorescence intensity curve. The hydrophobicity data for each particle fraction or particle group of the sample can be determined as the integral area under the portion of the fluorescence intensity curve corresponding to the specific particle fraction or group over time. Figure 5 The diagram shows three levels, F1, F2, and F3 (e.g.) Figure 4 The illustrative fluorescence data (those shown) are provided, where the integral areas A1, A2, and A3 below the fluorescence curves 51, 52, and 53 for each fraction F1, F2, and F3 represent the hydrophobicity of the corresponding fractions F1, F2, and F3. The hydrophobicity of each fraction depends in particular on the number of hydrophobic particles, the hydrophobicity level of the corresponding particles (the number of hydrophobic structural portions in the particles), and the particle size of the corresponding particles.

[0094] In embodiments of the invention, the number of particles of a given particle size is determined based on light scattering measurements or turbidity measurements. Turbidity data can be used to determine the relative number of particles in each fraction. The turbidity of each fraction (measured via light scattering techniques) can depend in particular on the number of particles, the size of the corresponding particles, the shape of the corresponding particles, and the color or reflectivity of the corresponding particles.

[0095] Figure 6 An example is shown of the scattering signal 61 and fluorescence data 62 that the monitoring unit can provide for samples fractionated into two particle groups, or fractions F4 and F5. In the example, small particles such as colloids in fraction F4 leave first from the separation stage (e.g., a classifier), followed by heavier particles such as aggregates (with the longest retention time) in fraction F5, which leave last. As can be seen, for fraction F4 with small particles, scattering 61 increases first from baseline 60, while fraction F5 with large particles and high particle concentration receives even higher scattering. Fluorescence 62 begins to increase slightly earlier than light scattering. The fluorescence value of fraction F4 is higher than that of fraction F5, meaning that the larger particles are less hydrophobic.

[0096] In embodiments of the present invention, at least one or more of the following key variables can be derived from the provided data:

[0097] - One or more particle counts: The total count and the count for each particle group are derived from the turbidity signal;

[0098] - One or more particle sizes are derived from the retention time of each particle group in the system, i.e., the time when the particles leave the classifier;

[0099] - The particle size distribution is derived from turbidity and one or more retention times;

[0100] - Hydrophobicity of particles: The overall hydrophobicity and the hydrophobicity of each particle group are derived from the fluorescence signal;

[0101] - The hydrophobicity distribution of the particles is derived from the fluorescence signal and one or more retention times.

[0102] In embodiments of the invention, signal processing and calculation of key variables of particle properties may include one or more of signal filtering, averaging, derivation, and baseline correction, or any other basic mathematical operations and / or the use of applicable functions to modify the measurement signal. Baselines can be removed from the raw signal of the graded sample, and cumulative sums can be calculated from the signal. The cumulative sum of turbidity signals can be correlated with particle counts, and the cumulative sum of fluorescence signals can be correlated with particle hydrophobicity. The hydrophobicity and count of each particle group can be derived from the signal at certain time intervals. The total hydrophobicity and total count can be derived from the total signal of the graded sample. Turbidity, particle size, and number in a sample group can be determined by measuring absolute or relative values. If absolute values ​​are measured, the processing means used to process the measurement signal for each particle group can be calibrated relative to a known sample.

[0103] Example 1

[0104] Figure 7A and 7B These are bar graphs illustrating the count and size of hydrophobic particles in samples taken at different measurement points during a water treatment process in operation. In the water treatment process from which samples are extracted, a first separation stage 18 includes a flotation tank, and a second separation stage 19 includes a sand filter. Water is fed from the sand filter to a membrane filtration stage 3, which includes a reverse osmosis (RO) stage. During this process, hydrophobic particles of a specific size are measured using optical sensors (fluorescence and scattering). Samples extracted from specific points in the water treatment process are then analyzed offline in the laboratory. Figure 7A and 7BAs can be seen, in the analyzed water treatment processes, the number of hydrophobic particles decreased by 62% after flotation and by 92% after sand filtration, relative to the raw water. Therefore, it is evident that the water pretreatment process affects the quantity and properties of hydrophobic particles, and this can be used as a quality control parameter to adjust the coagulant and / or flocculant or other chemicals during water pretreatment, preferably by metering the addition of coagulant and / or flocculant. The quantity and properties of hydrophobic particles can also be used as quality control parameters to adjust the metering of coagulant and / or flocculant, thereby preventing, reducing, or keeping scale under control in subsequent water treatment steps, such as scaling on membrane filters, or scaling on surfaces in the pretreated water used in subsequent processes.

[0105] Example 2

[0106] The goal of this study was to evaluate the performance of an online water quality monitoring device for surface water, when the device is capable of measuring particle size and hydrophobicity online. Three different types of surface water (1, 2, and 3) with varying total organic carbon (TOC) concentrations were used in this study. Three pretreatment chemicals (coagulants) (1, 2, and 3) were also used. First, reference samples of each of the surface waters (1, 2, and 3) were analyzed before the pretreatment chemicals were added in metered amounts. Figure 7C The table shows the count of hydrophobic particles in surface water samples (5A, pretreated water after flotation) after chemical pretreatment using different pretreatment chemicals 1, 2, and 3. The results show that the online monitoring device can detect changes in water quality (compared to a reference sample) and changes between water samples treated with different chemicals. It is also evident that the type of chemical has a significant impact on the extent to which hydrophobic particles are removed from surface water. Lower columns indicate better removal of hydrophobic particles by the corresponding chemical. Similarly, Figure 7D The table shows the hydrophobic particle counts for all surface waters 1, 2, and 3 treated with different pretreatment chemicals 1, 2, and 3. It can be seen that the type of surface water significantly influences the selection of pretreatment chemicals. For example, chemical 3 effectively removed hydrophobic particles from surface water 1, but it was less suitable for surface waters 2 and 3.

[0107] In embodiments of the invention, the metered addition of one or more pretreatment chemicals, such as coagulants and / or flocculants, is controlled to orient the hydrophobic conditions in the pretreated water toward a target hydrophobic condition.

[0108] In embodiments of the invention, the metered addition of one or more pretreatment chemicals, such as coagulants and / or flocculants, is controlled to reduce or maintain the amount or count of hydrophobic particles of a certain size below or at a predetermined target value. In embodiments of the invention, the metered addition of one or more pretreatment chemicals, such as coagulants and / or flocculants, is controlled to reduce or maintain the total hydrophobicity of the particles below or at a predetermined target value after chemical pretreatment.

[0109] In embodiments of the invention, the metered addition of one or more pretreatment chemicals, such as coagulants and / or flocculants, is controlled to reduce the count of hydrophobic particles after chemical pretreatment.

[0110] In embodiments of the invention, the metered addition of one or more pretreatment chemicals, such as coagulants and / or flocculants, is controlled to reduce the count of hydrophobic particles, thereby reducing the risk of membrane fouling.

[0111] Control can be performed manually or preferably automatically.

[0112] In embodiments of the invention, the control of the metered addition of one or more pretreatment chemicals, such as coagulants and flocculants, can be based on any control algorithm that outputs chemical dosage values ​​according to monitored characteristics such as the count of measured hydrophobic particles. An example of the metered addition of pretreatment chemicals (milligrams per liter of water) varying with the hydrophobic particle count is shown in… Figure 8 middle.

[0113] In an embodiment of the present invention, the metering controller can be a proportional-integral (PI) type controller.

[0114] In embodiments of the invention, feedback-controlled metering can be used, wherein the metering is based on a sample extracted from chemically treated water (e.g., Figure 1 The sample 15A or 15B in the control chemical is added in a controlled manner.

[0115] In embodiments of the invention, feedforward-controlled metering addition control can be used, wherein the control is based on samples extracted from the incoming raw water stream 15C before or after coagulation and chemical addition (e.g., samples from the raw water stream 15C before or after chemical addition). Figure 1 The sample 15C) controls the metering of chemicals added. Feedforward control allows for a rapid and proactive response to large changes in influent quality: the metering of chemicals can be immediately adapted to the change.

[0116] In embodiments of the present invention, both feedforward dose addition control and feedback metering addition control can be used.

[0117] In embodiments of the present invention, feedforward metering control can be used for one chemical (e.g., a coagulant), and feedback metering control can be used for another chemical (e.g., a flocculant).

[0118] In embodiments of the present invention, two or more chemicals may be added. In embodiments of the present invention, the type of chemical may be changed based on measurement results.

[0119] According to aspects of the invention, cleaning of the membrane filter unit can be controlled, initiated, or rearranged based on measured hydrophobic conditions. In embodiments of the invention, cleaning of the membrane filter unit can be initiated or rearranged based on short-term or long-term measurements of hydrophobic conditions. For example, if short-term or long-term measurements exceed a threshold level, cleaning can be controlled, initiated, or rearranged. Mechanical or chemical cleaning, or both, of the membrane can be used. Chemical cleaning agents that remove deposits and restore the membrane's normal capacity and separation properties can be used. Figure 1 In the exemplary embodiment shown, controller 13 may be connected to membrane cleaning system 3A of the membrane filtration stage. In one embodiment, reports or alarms may be provided to the water treatment process operator regarding the need to control, initiate, or reschedule membrane cleaning. In one embodiment, control of chemical cleaning may include controlling the metered addition of one or more cleaning agents.

[0120] According to one aspect of the invention, the performance of a membrane filter unit can be controlled based on measured hydrophobic conditions. Membrane performance can be described by removal rates, such as desalination rate, permeate flux, and / or pressure differential. Higher removal rates, higher permeate flux, and lower pressure differentials through the membrane are examples of indicators of better membrane filter performance.

[0121] Figure 9The monitoring unit 12 according to an exemplary embodiment is schematically shown. The monitoring unit can be considered as having two main parts: a preparation section and a measurement section. The preparation section can perform sampling, staining of the sample, and separation of the sample into particle groups. The preparation section may include a sampling device 81, which may be arranged, for example, to extract a substantially continuous stream of sample from a sidestream 15 of pretreated water, or, for example, to sequentially extract individual samples (such as batch samples or “plunger samples”) of predetermined sizes at predetermined intervals. A staining unit 82 with a dye reservoir (not shown) may be provided to feed an appropriate amount of dye to the sample before separating the particles into groups. A clean water source 80 and a pump (not shown) may be provided to drive the sample or water forward through a classifier in a system using suitable valves (not shown). The prepared sample from the preparation section (e.g., the classifier) ​​may be measured using one or more detectors 84, such as fluorescence detectors and light scattering or turbidity detectors. The measurement section of the monitoring unit may also include a data processing unit to process the measurement signal, such as extracting key variables, to provide measurement results 17. Alternatively, data processing 85 can be provided in a separate computing entity or computer, such as the process controller 13 of preprocessing stage 1. Such a computing entity can be, for example, a programmable logic controller (PLC) or an industrial computer for the automated operation and data collection of the system.

[0122] It is to be understood that the embodiments of the present invention disclosed herein are not limited to the specific structures, processes, or materials disclosed herein, but extend to their equivalents as will be recognized by those skilled in the art.

[0123] It should also be understood that the terminology used herein is for the purpose of describing specific implementations only and is not intended to be restrictive.

[0124] Throughout this specification, the reference to "an embodiment" or "an embodiment" means that a specific feature, structure, or characteristic described with respect to that embodiment is included in at least one embodiment of the invention. Therefore, the appearance of the phrase "in one embodiment" or "in an embodiment" in various places throughout this specification does not necessarily refer to the same embodiment.

[0125] The various parts, structural elements, constituent elements, and / or materials used herein may exist in a common list for convenience. However, these lists should be interpreted as if each member of the list were individually identified as a separate and distinct member. Therefore, a single member of such a list should not be interpreted solely based on its statement in the common group without to the contrary as a practically existing equivalent of any other member of the same list. Furthermore, various embodiments and examples of the invention may be mentioned herein along with alternatives to its various components. It should be understood that such embodiments, examples, and alternatives should not be interpreted as practically existing equivalents of each other, but rather as separate and independent representations of the invention. Well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the invention.

[0126] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details, such as examples of length, width, shape, etc., are provided to provide a comprehensive understanding of embodiments of the invention.

[0127] While the foregoing examples illustrate the principles of the invention in one or more specific applications, those skilled in the art will understand that many modifications in form, usage, and detail of the implementation methods can be made without inventiveness and without departing from the principles and concepts of the invention. Therefore, the invention is not intended to be limited except as set forth in the claims below.

[0128] In particular, the present invention also relates to the following items:

[0129] Project 1. Methods for controlling water treatment processes, including:

[0130] In a pretreatment process that includes a coagulation step and / or a flocculation step and at least one separation step, at least one pretreatment chemical is added to the water stream to reduce the amount of dissolved and / or particulate matter in the water stream.

[0131] Monitoring the hydrophobic conditions in the upstream and / or downstream water flow where at least one pretreatment chemical is added, and

[0132] The metered addition of the at least one pretreatment chemical to the water stream is controlled based on at least monitored hydrophobic conditions.

[0133] Project 2. The method according to Project 1, wherein the at least one separation step includes one or more of a flotation step, a sedimentation step, and a filtration step.

[0134] Project 3. The method according to Project 1 or 2, wherein the control includes controlling the metered addition of the at least one pretreatment chemical to cause the hydrophobic conditions in the water flow to shift or be maintained below or at a target hydrophobic condition.

[0135] Project 4. The method according to Project 1, 2 or 3, wherein the monitoring includes classifying a sample of water flow into two or more particle groups based on particle size and / or particle mass.

[0136] Item 5. The method according to any one of Items 1-4, wherein the monitored and / or target hydrophobic conditions include one or more of the following:

[0137] i) At least a certain particle size and their hydrophobicity

[0138] ii) Hydrophobicity of at least a certain particle size

[0139] iii) The quantity or count of hydrophobic particles of a certain size

[0140] iv) Hydrophobic distribution of particles

[0141] v) The overall hydrophobicity of water flow,

[0142] vi) Total particle count,

[0143] vii) Particle count of one or more particle groups,

[0144] viii) Particle size distribution.

[0145] ix) Hydrophobicity of one or more particle groups.

[0146] Project 6. The method according to any one of Projects 1-5, further comprising membrane filtration of a pretreated water stream downstream of a pretreatment process, wherein the control of metering the addition of the at least one pretreatment chemical is configured to reduce membrane fouling in the membrane filtration.

[0147] Item 7. The method according to any one of Items 1-6, wherein the control of the metered addition of the at least one pretreatment chemical includes one or more of the following:

[0148] i) Feedback-based control based on samples extracted from the water stream downstream of the addition of at least one pretreatment chemical, preferably after the at least one separation step.

[0149] ii) Feedforward control based on samples extracted from upstream water flow containing at least one pretreatment chemical, and

[0150] iii) Feedforward control of the first of the at least one pretreatment chemical and feedback control of the second of the at least one pretreatment chemical.

[0151] Item 8. The method according to any one of Items 1-7, wherein the monitored and / or target hydrophobic conditions include:

[0152] Hydrophobicity was determined based on fluorescence measurements, and

[0153] The amount or count of particles is determined based on optical measurements, such as light scattering measurements or turbidity measurements.

[0154] Item 9. The method according to any one of Items 1-8, wherein:

[0155] Based on particle size and / or mass, the water sample is divided into two or more particle groups.

[0156] Before or during grading, the samples are stained with a fluorescent dye, preferably Nile Red dye.

[0157] Fluorescence intensity data over time were measured for each cohort of stained samples.

[0158] The hydrophobicity of each group is calculated from the fluorescence intensity data by integrating the measured fluorescence intensity over time.

[0159] Item 10. The method according to any one of items 1-9, further comprising membrane filtration of a pretreated water stream downstream of a pretreatment process, and cleaning of the membrane filtration controlled, initiated, or rearranged based on monitoring of the water stream hydrophobic conditions, said cleaning preferably comprising metered addition of at least one chemical cleaning agent.

[0160] Project 11. A control system for implementing the control method according to any one of Projects 1-10, the control system comprising a metering addition unit configured to add at least one pretreatment chemical to a water flow, an online monitoring unit configured to monitor the hydrophobic conditions of the water flow, and a control unit configured to control the metering addition unit based on hydrophobic condition data provided by the online monitoring unit.

[0161] Item 12. The system according to Item 11, wherein the online monitoring unit includes optical detectors, such as fluorescence detectors and light scattering detectors or turbidity detectors.

[0162] Item 13. The system according to Item 11 or 12, further comprising a membrane cleaning system controlled based on hydrophobic condition data provided by an online monitoring unit.

[0163] Project 14. Application of online hydrophobicity monitoring units in water treatment control processes.

[0164] Item 15. Use of the method according to any one of Items 1-10 for preventing or reducing scaling on surfaces such as pipes, heat exchangers, instruments, cooling water systems, or other underwater surfaces and splash zones in subsequent water treatment steps such as membrane filtration, or in one or more subsequent process steps using water from the pretreatment process.

[0165] Item 16. Use of the method according to any one of Items 1-10 for optimizing hydrophobic conditions on surfaces such as pipes, heat exchangers, instruments, cooling water systems, other underwater surfaces, and splash zones in subsequent water treatment steps, such as membrane filtration, or in one or more subsequent process steps using water from a pretreatment process.

[0166] Item 17. According to the use described in Item 16 or 15, one or more process steps include process steps in the pulp and paper industry, the food and beverage industry, the mining industry, or the petroleum industry.

Claims

1. Methods for controlling water treatment processes, including: - In a pretreatment process including a coagulation step and / or a flocculation step and at least one separation step, at least one pretreatment chemical comprising a coagulant and / or a flocculant is added to the water stream to reduce the amount of dissolved and / or particulate matter in the water stream, wherein the at least one separation step includes a flotation step or a sedimentation step. - In the online monitoring unit, the hydrophobic conditions in the upstream and / or downstream water flow where at least one pretreatment chemical has been added are monitored, and - The metering addition of the at least one pretreatment chemical to the water flow is controlled based on at least monitored hydrophobic conditions, wherein the metering addition of one or more pretreatment chemicals is controlled based on monitoring at least hydrophobic particles. - In subsequent membrane filtration water treatment steps, if short-term or long-term hydrophobic conditions exceed a threshold level, cleaning of the membrane filter is initiated or scheduled, including metered addition of chemical cleaning agents, and - To prevent or reduce scaling on surfaces in one or more subsequent process steps using water from the pretreatment process, said surfaces being pipes, heat exchangers, instruments, cooling water system surfaces, other underwater surfaces, or splash zones, and in The process controller for the pretreatment process is connected to the membrane cleaning system in the membrane filtration stage following the pretreatment process, and The metering of one or more pretreatment chemicals is controlled based on the monitoring and control of at least hydrophobic particles, and The membrane cleaning system is controlled based on the monitored hydrophobic conditions.

2. The method of claim 1, wherein the at least one separation step comprises one or more of a flotation step, a sedimentation step, and a filtration step.

3. The method according to claim 1 or 2, wherein the control comprises controlling the metered addition of the at least one pretreatment chemical to cause the hydrophobic conditions in the water flow to shift or be maintained below or at a target hydrophobic condition.

4. The method according to claim 1 or 2, wherein the monitoring includes classifying a sample of the water flow into two or more particle groups based on particle size and / or particle mass.

5. The method according to claim 1 or 2, wherein the monitored and / or target hydrophobic conditions include one or more of the following: i) At least a certain particle size and their hydrophobicity ii) Hydrophobicity of at least a certain particle size iii) The quantity or count of hydrophobic particles of a certain size iv) Hydrophobic distribution of particles v) The overall hydrophobicity of water flow, vi) Total particle count, vii) Particle count of one or more particle groups, viii) Particle size distribution. ix) Hydrophobicity of one or more particle groups.

6. The method according to claim 1 or 2, further comprising membrane filtration of the pretreated water stream downstream of the pretreatment process, wherein the control of metering the addition of the at least one pretreatment chemical is configured to reduce membrane fouling in the membrane filtration.

7. The method according to claim 1 or 2, wherein the control of the metered addition of the at least one pretreatment chemical comprises one or more of the following: i) Feedback-based control based on samples extracted from downstream water streams containing at least one pretreatment chemical. ii) Feedforward control based on samples extracted from upstream water flow containing at least one pretreatment chemical, and iii) Feedforward control of the first of the at least one pretreatment chemical and feedback control of the second of the at least one pretreatment chemical.

8. The method according to claim 1 or 2, wherein the control of the metered addition of the at least one pretreatment chemical comprises one or more of the following: i) Feedback-based control based on samples extracted from downstream water flow following the at least one separation step. ii) Feedforward control based on samples extracted from upstream water flow containing at least one pretreatment chemical, and iii) Feedforward control of the first of the at least one pretreatment chemical and feedback control of the second of the at least one pretreatment chemical.

9. The method according to claim 1 or 2, wherein the monitored and / or target hydrophobic conditions include: Hydrophobicity was determined based on fluorescence measurements, and The quantity or count of particles is determined based on optical measurements.

10. The method of claim 9, wherein the optical measurement is a light scattering measurement or a turbidity measurement.

11. The method according to claim 1 or 2, wherein: Based on particle size and / or mass, the water sample is divided into two or more particle groups. The sample is stained with a fluorescent dye before or during grading. Fluorescence intensity data over time were measured for each cohort of stained samples. The hydrophobicity of each group is calculated from the fluorescence intensity data by integrating the measured fluorescence intensity over time.

12. The method of claim 11, wherein the fluorescent dye is Nile Red dye.

13. The method according to claim 1 or 2, further comprising membrane filtration of the pretreated water stream downstream of the pretreatment process, and hydrophobic condition control, initiation, or rearrangement of cleaning of the membrane filtration based on monitoring of the water stream.

14. The method of claim 13, wherein cleaning the membrane filter comprises metering the addition of at least one chemical cleaning agent.

15. The method according to claim 1 or 2, wherein the hydrophobic conditions monitored in the water flow are determined by measuring hydrophobicity based on fluorescence measurements and determining the amount or count of particles based on light scattering measurements.

16. A control system for implementing the control method according to any one of claims 1-15, the control system comprising a metering addition unit configured to add at least one pretreatment chemical to a water flow, an online monitoring unit configured to monitor the hydrophobic conditions of the water flow, and a control unit configured to control the metering addition unit based on hydrophobic condition data provided by the online monitoring unit.

17. The system of claim 16, wherein the online monitoring unit includes an optical detector.

18. The system of claim 17, wherein the optical detector is a fluorescence detector and a light scattering detector or a turbidity detector.

19. The system according to claim 16 or 17, further comprising a membrane cleaning system controlled based on hydrophobic condition data provided by an online monitoring unit.

20. Use of the method according to any one of claims 1-15 for preventing or reducing scaling on surfaces in subsequent water treatment steps or in one or more subsequent process steps using water from the pretreatment process.

21. Use of the method according to any one of claims 1-15 for preventing or reducing scaling on surfaces during membrane filtration or in one or more subsequent process steps using water from the pretreatment process.

22. The use according to claim 20 or 21, wherein the surface is the surface of a pipe, heat exchanger, instrument, cooling water system, or other underwater surface and splash zone.

23. The use according to claim 20 or 21, wherein the one or more process steps comprise process steps in the pulp and paper industry, the food and beverage industry, the mining industry, or the petroleum industry.

24. Use of the method according to any one of claims 1-15 for optimizing hydrophobic conditions on a surface in a subsequent water treatment step, or in one or more subsequent process steps using water from the pretreatment process.

25. The use according to claim 24, for optimizing hydrophobic conditions on a surface in membrane filtration or in one or more subsequent process steps using water from the pretreatment process.

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