Techniques for managing fouling formation in water filtration systems and reverse osmosis (RO) and nanofiltration (NF) systems implementing same

Abstract

The present disclosure relates to a filtration system. The filtration system comprises: at least one inlet; at least one filtration membrane; at least one pump and a controller configured to cause a first drive signal to be provided to the at least one pump such that the generated pressure produces the output permeate stream over a first time period at a recovery substantially equal to a first target recovery, the first target recovery is greater than a maximum non-fouling recovery of the at least one filtration membrane and less than 100%, and causing one or more scale inhibitor doses to be introduced into the at least one filtration membrane at predetermined times within the first time period. The system combines continuous and batched NF / RO elements based on the limits of end user facilities to achieve a targeted balance, e.g., between recovery and power consumption, and to reduce the long-term operating costs of the plant. Also disclosed herein is a system for extending batch operation to a second initiation period by injection of scale inhibitors that allows for higher water recovery.

Description

[0001] This application is a divisional of application No.: 202080100949.2, which entered the Chinese national phase from PCT International Application No. PCT / US2020 / 034674 entitled “Techniques for Managing Fouling in Water Filtration Systems and Reverse Osmosis (RO) and Nanofiltration (NF) Systems Implementing the Same.”

[0002] Cross Reference to Related Applications

[0003] This application claims the benefit of U.S. Provisional Patent Application Serial No. 62 / 991,393, filed March 18, 2020, which is hereby incorporated by reference in its entirety into the present application. TECHNICAL FIELD

[0004] The present specification relates to filtration systems and managing fouling within them. BACKGROUND

[0005] Water filtration systems generally include at least one filtration membrane for producing a permeate from a feed stream. One approach to water filtration employs a steady-state continuous reverse osmosis (RO) operation / cycle and a pump that transfers the feed through the one or more filtration membranes at a substantially constant pressure. The ratio of the feed that exists as permeate relative to the feed that exists as retentate / rejectant determines the recovery of the system. Such continuous flow systems are typically operated at a recovery rate that is equal to or below the rate that initiates fouling conditions. Thus, continuous flow systems have a relatively low maximum recovery rate, e.g., 50-75%, to avoid fouling and contamination.

[0006] Another approach to water filtration employs a batch RO operation / cycle. In batch RO, the pump varies the pressure over time to overcome the osmotic pressure of the one or more filtration membranes. Batch RO systems have a relatively high recovery rate compared to continuous flow systems, but such systems must be periodically flushed to maintain permeate flux. BRIEF DESCRIPTION OF DRAWINGS

[0007] Various aspects and features of the disclosure will be better appreciated and understood from a conjunction of the following detailed description with the accompanying drawings, of which:

[0008] The drawings included herewith are for illustrating various examples of the articles, methods, and apparatuses taught herein and are not intended to limit the scope of the teaching in any way.

[0009] Figure 1 An example graph showing a continuum of filtration systems having opposite extremes representing continuous RO operation and batch RO operation, respectively, is shown.

[0010] Figure 2AA block diagram showing an example filter configuration for use during continuous RO operation is shown.

[0011] Figure 2B A block diagram showing an example filter configuration for use during batch RO operation is shown.

[0012] Figure 3 A block diagram showing an example filtration system according to embodiments of the disclosure is shown.

[0013] Figure 4 A graph showing various recovery target rates over time (T) for a filtration system performing one or more filtration operation sequences according to embodiments of the disclosure is shown. Figure 3

[0014] Figure 5 A graph showing various recovery target rates over time (T) for a filtration system performing one or more filtration operation sequences according to embodiments of the disclosure is shown. Figure 4

[0015] Figure 6 A graph showing various recovery target rates over time (T) for a filtration system performing one or more filtration operation sequences according to embodiments of the disclosure is shown. Figure 3

[0016] Figure 7 A graph showing various recovery target rates over time (T) for a filtration system performing one or more filtration operation sequences according to embodiments of the disclosure is shown. Figure 3

[0017] Figure 8 A graph showing various recovery target rates over time (T) for a filtration system performing one or more filtration operation sequences according to embodiments of the disclosure is shown. Figure 3 DETAILED DESCRIPTION

[0018] The popularity and adoption of RO-based filtration systems continues to increase, particularly in commercial and large-scale filtration plants. RO-based water filtration systems fall into one of two modes of operation, either continuous RO or batch RO. While both modes of RO filtration systems use similar filtration technologies, such as NF, seawater RO, and brackish water RO technologies, filtration systems that implement continuous RO operation are at one end of a continuum relative to filtration systems that implement batch RO operation.

[0019] This continuum can be better understood by way of illustration. Figure 1 ​​​​​One such example continuum is shown, having continuous RO and batch RO operations at opposite ends / extremes of the continuum. In particular, the continuous RO system operates at a relatively low recovery rate to achieve a non-scaling steady state (with or without antiscalant), with an operating time measured in weeks to months. On the other hand, the batch RO system operates at a recovery rate above the non-scaling steady state (i.e., 100% recovery), with an operating time that is typically a small fraction of the amount of time the continuous RO system operates before the filtration membranes are flushed (e.g., by feed). For example, some batch RO operations last only a few minutes to a few hours before the flushing cycle takes place.

[0020] Continuous RO systems are characterized by different structural and operational differences relative to batch RO systems. New and existing filter designs implement batch RO when high recovery rates are needed, continuous operation when it is desirable to run the equipment steadily, uninterrupted, for weeks or months, with no or low antiscalant dosage being preferred, and / or reduced water recovery being acceptable.

[0021] In either case, the design of a water filtration system employing NF and RO technology typically begins with identifying the recovery rate at which the selected filtration membranes begin to foul, which is typically calculated without the use of antiscalant (also referred to herein as antiscalant). The recovery rate of a filtration system is expressed as a ratio defined by the portion of the feed (or feed water) entering the filtration system that remains as product retentate (also referred to herein as retentate or simply retentate) output through one or more drain valves. Thus, a recovery below 100% includes at least a portion of the feed that is output as product retentate.

[0022] Accordingly, product retentate, also referred to herein as retentate, refers to the portion of the feed that does not pass through the filtration membranes. On the other hand, permeate refers to the portion of the feed that passes through the filtration membranes, output as, for example, “clean” water, although the permeate can not necessarily be potable water, depending on the configuration of the filtration system and the intended use of the permeate.

[0023] It is noted that the following disclosure generally refers to the point at which scaling occurs to the point of supersaturation of scale-forming compounds, as well as when fouling occurs to the point of critical flux (or critical concentration), at which point permeate output is significantly reduced or otherwise prevented, referred to simply as scaling and fouling, respectively. Some examples and scenarios discussed herein can refer to one or both of these scaling and fouling conditions, without necessarily referring to both. For example, various aspects and features disclosed herein relate to maximum non-scaling recovery rates. This value is not limited to scaling alone, but can also refer to the maximum rate before the presence of fouling conditions.

[0024] In the case of a continuous RO / NF system, as shown in FIG. 1, Figure 2A the maximum recovery rate (or set point) is established at a rate just below the recovery rate identified when the onset of the scaling condition occurs. Alternatively, as discussed in further detail below, the maximum recovery rate set point can be run above the recovery rate identified when the scaling condition occurs with the use of a scale inhibitor. In any case, the continuous RO / NF system then operates for a period of time, typically measured in weeks / months, in a non-scaling steady state. During operation, the continuous RO / NF system consumes a substantially constant amount of power, for example, to pass the feed stream through the filtration membrane by the load of a pump, and then the resulting product retentate is disposed of via a sewer or provided to an additional filtration stage, which further increases the operating cost of such a system. Continuous RO / NF systems typically operate at a fixed recovery rate of about 50-70% to maintain the non-scaling steady state.

[0025] In contrast, in the case of a batch RO / NF system, as shown in FIG. 2, Figure 2B the maximum recovery rate (or set point) is set above the recovery rate identified when the onset of the scaling condition occurs. This configuration can enable a cyclic batch operation, where 100% of the feed is converted to permeate after a period of time, after which the RO system is flushed with feed to expel the final batch concentrate of the run, and then the batch cycle is restarted.

[0026] For example, using a batch RO / NF, a maximum recovery rate of 100% can be set, such that no bleed is required to output the product retentate. The RO / NF system is set at such a recovery rate, and then operated in a non-steady state, and the pressure is varied over time to overcome the osmotic pressure of the filtration membrane. The total amount of time in this non-steady state operation can be measured in minutes or hours, depending on the particular configuration of the filtration system. One advantage of batch RO is that high recovery rates can be achieved without the use of a scale inhibitor.

[0027] However, at some point during such batch operation, the osmotic pressure of the filtration membrane will exceed the maximum amount of pressure that the pump of the system is capable of generating. System designers typically limit the amount of time that the system is operated in such a non-steady state, i.e., outside the scaling limit, to avoid potential damage to the filtration system and / or unsafe conditions. Such limitations can include, for example, careful monitoring of the system pressure and / or preventing operation in the non-steady state for more than a fixed predetermined amount of time. Thus, a high recovery rate, i.e., 100%, is achieved at the expense of downtime to flush the filtration membrane (and reduced recovery rate), as well as additional wear and tear on the pump from the high frequency batch cycling.

[0028] In the past two decades, scale inhibitors have improved significantly, allowing for higher recovery rates in both batch RO and continuous RO systems. Table 1 below shows the ability of various commercially available scale inhibitors to over-saturate relative to 100% maximum for no scale inhibitor, or the maximum absolute concentration of the primary scaling compound, or for some NF / RO rejection streams, the maximum Langelier Saturation Index (LSI) in pH units, relative to the saturation pH, for calcium carbonate scale. In Table 1, the maximum over-saturation reported from one example source is shown in column 2, but it should be noted that as scale inhibitor research progresses, results can change over time.

[0029] Commercial / large scale NF / RO systems typically operate at a fixed feed rate and a fixed recovery rate (which results in a fixed permeate and a fixed reject rate), and such systems use scale inhibitors dosed into the feed to achieve over-saturation. The dosage of scale inhibitor is typically at 5 mg / l or below to reduce chemical costs. However, the market demand for higher recovery rates and the re-use demand of the wastewater market continues to increase. Increasing the scale inhibitor dosage is still the primary means to meet these demands. At the same time, these market demands result in higher membrane fouling rates and associated increases in chemical costs.

[0030] There are also challenges associated with treating NF / RO reject streams containing scale inhibitors. These challenges include the need to post-treat these streams in settling and thermal reduction systems, and / or the impact of scale inhibitors on receiving streams in the environment. Additional challenges include potential incompatibilities between membranes and scale inhibitors, and unexpected deleterious interactions between feed stream components and scale inhibitors, either one or both of which can reduce the performance of the filtration system.

[0031] Table 1

[0032] Scale or contaminant Maximum reported by industry sources LSI (calcium carbonate) +2.9 Calcium sulfate 400％ Strontium sulfate 1200％ Barium sulfate 8000％ Calcium fluoride 12000％ Silica 300 ppm or higher Iron 5 ppm Aluminum 4 ppm

[0033] The continuing improvement of water filtration systems employing RO technology depends at least in part on the development of filtration technologies that allow the features and advantages of continuous RO and batch RO systems to be integrated in a manner that achieves relatively high recovery rates without the existing drawbacks of such rates, such as wear and tear on system components, high power consumption, and the necessity of using scale inhibitors, among others.

[0034] In addition, there is a need for a filtration system that, in general terms, can operate at the midpoint of the continuum discussed above with respect to Figure 1 continuous RO and batch RO systems, to be able to balance multiple target parameters, such as total power consumption, wastewater production, and other costs to be considered in system design, to achieve a desired water recovery rate that also meets various other requirements and goals specific to the particular filtration system.

[0035] With the foregoing in mind, the present disclosure is directed to techniques (e.g., systems and methods) that combine elements of continuous and batch NF / RO. Such systems and methods can take into account limitations of an end-user facility to achieve a target balance between, for example, recovery and power consumption, and to reduce long-term operating costs of a plant. Also disclosed herein are methods for extending a batch operation into a second priming period by injecting an antiscalant, which makes higher water recovery possible. The first and / or second priming periods can be extended, preferably, by using high pressure filtration membrane modules and pumps capable of producing variable pressures up to 90-120 bar, for example, to displace feed water through the high pressure filtration membrane modules. In addition to scaling, the techniques disclosed herein can also be used for contamination management, as contamination similarly has a negative impact on pressure and recovery of NF / RO systems.

[0036] Unless otherwise specified herein, the term "substantially" when used in reference to a quality, characteristic or value means ±10% of that quality, characteristic or value.

[0037] The term "coupled" as used herein means any connection, coupling, link, or the like, and "fluidly coupled" means a coupling that allows fluid to communicate from one element to another. Such "coupled" elements are not necessarily directly connected to one another and can be separated by intermediate components / elements. Likewise, the term "directly coupled" means a connection between elements without the use of intermediate elements, and "direct fluid coupling" as used herein means a coupling of elements whereby fluid can pass from one element to another without the use of intermediate components / elements.

[0038] Turning to the drawings, Figure 3 One example of a filtration system 300 consistent with the present disclosure is shown. As shown, the filtration system 300 includes a controller 302, at least one pump 304, and a filtration stage 306.

[0039] The controller 302 includes at least one processing device / circuitry, such as a microcontroller (MCU), a digital signal processor (DSP), a field programmable gate array (FPGA), a reduced instruction set computer (RISC) processor, an x86 instruction set processor, a microcontroller, an application specific integrated circuit (ASIC). Preferably, the controller 302 is implemented within a programmable logic controller (PLC). The controller 302 is preferably communicably coupled to the at least one pump 304. The controller 302 can be configured to cause a drive signal to be provided to the pump 304 to cause the pump 304 to produce a target amount of pressure.

[0040] The controller 302 is also preferably communicably coupled to at least one discharge valve, such as the discharge valve 308. The controller 302 can be configured to cause a control signal to be provided to the discharge valve 308. Preferably, the control signal is configured to cause the discharge valve 308 to transition between a closed position and a plurality of open positions. Each of the plurality of open positions allows a different amount of feed water of the feed stream 309 to be output as a product retentate 310 (also referred to herein as a concentrated retentate, retentate water, or simply retentate). As discussed further below, and in accordance with an embodiment, the filtration valve arrangement 312 can switchably couple the feed stream transferred by the at least one pump 304 to one or more filtration stages 314 (also referred to herein as a filter array). Thus, the controller 302 can be configured to cause a control signal to be provided to the valve arrangement 312 that causes the one or more filtration stages 314 to be switchably fluidically coupled to the feed transferred by the at least one pump 304.

[0041] The discharge valve 308 can be implemented as an electromechanical valve configured to be actuated by a received control signal as described above. However, the discharge valve 308 can be implemented as any other suitable device including a manual valve that requires actuation of the valve by a user-provided force, such as by a technician or engineer. The filtration stage 306 includes at least one filtration membrane 311. Preferably, the at least one filtration membrane 311 is a NF or RO filtration membrane.

[0042] In an embodiment, the filtration stage 306 includes at least one high pressure NF or RO filtration membrane having a housing / shell capable of withstanding an operating pressure of at least 1000-1800 psi, preferably at least 1740 ± 5 psi. In one non-limiting implementation, the at least one filtration membrane 311 is implemented as a plate-and-frame (or spacer-tube) high pressure membrane module configured to withstand a working pressure of up to 1750 psi. For example, the at least one filtration membrane 311 can be implemented as an Aquazoom® high pressure filtration module having a pressure shell capable of withstanding 90-120 bar (1305-1745 psi) provided by CrossTek Membrane Technology LLC of Holbrook, Massachusetts. TM ultra-high pressure filtration module having a pressure shell capable of withstanding 90-120 bar (1305-1745 psi) provided by CrossTek Membrane Technology LLC of Holbrook, Massachusetts.

[0043] The at least one filtration membrane 311 preferably includes at least one inlet 311-1 (or input port) that is fluidically coupled to the feed stream 309 by way of the at least one pump 304. The at least one pump 304 can generate a pressure (preferably, a variable amount of pressure) to cause feed water (also referred to herein as feed) of the feed stream 309 to be received and transferred into the at least one filtration membrane 311. Note that, although not shown, the at least one pump 304 can be fluidically coupled to the feed stream 309 by way of a pre-filter 313.Figure 3 An example is depicted in which the inlets 311-1 are directly coupled to the pump 304, but such a configuration is not required. For example, at least one inlet 311-1 can be fluidly coupled to a drain of another filtration stage / filter system and configured to receive the retentate output through the drain as the feed stream 309. Alternatively, at least one inlet 311-1 can be fluidly coupled to a permeate output of another filtration stage / filter system and configured to receive the permeate output therefrom as the feed stream 309.

[0044] The at least one filtration membrane 311 also includes at least one outlet 311-2 to output the permeate 313 and at least one drain 311-3 to output the retentate 310. The outlet 311-2 of the at least one filtration membrane 311 can be, for example, fluidly coupled to an inlet of another filtration stage of the plurality of filtration stages 314 for further processing, depending on the desired configuration. The at least one drain 311-3 can also be fluidly coupled to an inlet of another filtration stage of the plurality of filtration stages 314 or, alternatively, to a sewer / waste backflow.

[0045] In an embodiment, the filtration stage 306 is optionally implemented in a plurality of different filtration stages, e.g., filtration stages collectively shown at 314, individually 314-1 through 314-2. Each of the plurality of filtration stages 314 can further include substantially similar filtration membranes or different types of filtration membranes and / or total number of filtration membranes relative to the other filtration stages. For example, a first filtration stage 314-1 can be configured with one or more filtration membranes of a first type of filtration membrane, and a second filtration stage 314-2 can be configured with one or more filtration membranes of a second type, the second type having a pressure shell capable of withstanding a higher maximum working pressure than the first type of filtration membrane. Such a change in filter type can be particularly advantageous when high pressure cycling is performed through the second filtration stage 314-2. In such a case, the valve arrangement 312 can switchably fluidly couple the feed from the at least one pump 304 to the second filtration stage 314-2 and switchably fluidly decouple the feed from the at least one pump 304 from the other filtration stages of the plurality of filtration stages 314, e.g., the first filtration stage 314-1, which do not necessarily have pressure shells of the particular pressure amount capable of withstanding high pressure cycling.

[0046] The filtration valve arrangement 312 can be implemented in an electromechanical valve configured to be actuated by a received control signal as described above. However, the filtration valve arrangement 312 can be implemented by other suitable devices including a manual valve that requires actuation of the valve by a user-provided force, e.g., by a technician or engineer.

[0047] The recovery of the filtration system, in one embodiment, can be calculated as the volume of permeate produced per volume of feed (or received feed water) consumed. For example, in a batch process, the recovery can be calculated by equation (1):

[0048]

[0049] Consider the case where the filtration system is flushed at 125 gpm for 3 minutes while running at 100 gpm for 30 minutes in a batch production process. Then, the overall recovery of the filtration system 300 can be 88.9% = (100 gpm x 30 min) / (100 gpm x 30 min + 125 gpm x 3 min). One advantage of batch RO treatment is that the filtration system can be run without the use of a scale inhibitor and exceed the maximum recovery without scaling by running for a period of time that is less than the time required for scaling to occur from the onset of scaling / pollution conditions, referred to herein as the first induction period.

[0050] The designer then determines the characteristics of the feed, such as feed 309, and preferably determines all of the scaling compounds and concentrations of feed 309. In addition, preferably, the end user's effluent or permeate quality requirements are determined, such as permeate conductivity, total dissolved solids (TDS, which can be calculated from conductivity), and, for example, organic content. Preferably, the effluent or permeate quality requirements are preferably based on conductivity because conductivity can be measured quickly on-line and is a strong indicator of general permeate quality. The designer can also determine the feed flow rate and the recovery target desired by the end user. For the example discussed herein, the feed flow rate is 100 gpm, the feed total dissolved solids (TDS) is 2000 ppm, and the end user desires a permeate TDS < 250 mg / 1.

[0051] The designer then makes a membrane selection, preferably, determining the scaling and TDS rejection characteristics of the selected membrane. For example, a brackish water RO membrane can be selected, with a 99.5% TDS rejection that can be used for TDS and scaling rejection.

[0052] The designer then determines the water recovery at the onset of scaling, or when the supersaturation of the scaling compound of interest first occurs. This maximum non-scaling recovery is determined at the temperature and other pretreatment feed conditions (e.g., scale inhibitor dosage, acid dosage) expected to be implemented on the filtration system, for example. For example, the maximum non-scaling recovery can be set at 80% recovery, although the specific set point for the maximum non-scaling recovery can vary based on the factors described above.

[0053] The designer then determines a first initiation time based on, for example, the temperature and other pre-treatment feed conditions (e.g., scale inhibitor dosage, acid dosage) expected to be implemented on the filtration system, for example, the time between when the maximum non-scaling recovery is reached (or first exceeded) and when scaling actually occurs. For example, the first initiation time can equal 25 minutes.

[0054] The designer can then optionally determine the hold-up amount of feed / reject in the filtration system. For example, the filtration system can be designed to have a 200 gallons of feed / reject hold-up.

[0055] The designer then preferably establishes a plurality of inputs (or operating parameters), including, for example, dynamic water / carrier fluid properties, scale, contaminants, and TDS (total dissolved solids) to produce a mass balance that allows tracking of the quality of the carrier fluid (e.g., water and components) entering the system and the effluent and permeate exiting the system. Note that the discharge rate is preferably set by the designer as an input. This mass balance shows the concentration of the above-mentioned parameters in the system as a function of time, and preferably tracks the recovery rate as a function of time.

[0056] The designer can then analyze the output of the above-mentioned mass balance and filtration system performance based on varying the above-mentioned various inputs / parameters, and preferably selects operating parameters for the filtration system that set the recovery rate between 100% recovery and the maximum non-scaling recovery that achieves the desired power consumption rate (and by extension cost) and average recovery rate of the filtration system. Preferably, the selected operating parameters also take into account the sewer / reject disposal cost and / or peak power consumption (e.g., current peaks when the pump of the recirculation filtration system is used for flushing, batch recirculation, etc.). The designer can also update or otherwise modify the selected operating parameters to change the operating set points as the conditions of the filtration system change (e.g., increase / decrease sewer disposal cost, increase / decrease power cost, and / or increase / decrease recovery rate target).

[0057] The selected operating parameters can then preferably be outputted as machine readable instructions that, when executed by a controller such as controller 302, cause a series of filtration operations to occur, such as Figure 4 one or more filtration sequences shown and discussed in further detail below. Such instructions can preferably be stored within a memory (not shown) of controller 302.

[0058] Extended break-in period for RO / NF filtration systems

[0059] The present disclosure also recognizes that by introducing an antiscalant at a predetermined time prior to the end of the first priming period (e.g., when scaling / pollution occurs), a second priming period can then be established. The present disclosure further identifies that the total recovery achieved by the operation of the filtration system 300 over the first priming period and the second priming period allows the filtration system 300 to achieve a higher total recovery relative to the recovery that the filtration system 300 could achieve by using the antiscalant dosing alone during the batch / continuous RO cycle. Such a first priming period and a second priming period can be factored into the filtration system design process, such as the example filtration system design process described above.

[0060] Note that, as described above, the feed 309 entering the filtration stage 306 can be from a retentate / holdover stream of another filtration stage / system. In such a case, the feed 309 can include an antiscalant. Then, when determining to dose to prime a second priming period as disclosed herein, the concentration / amount of antiscalant present in the feed 309 can be utilized along with the known efficiency of the antiscalant. For example, the antiscalant can have a time-dependent efficiency, potentially requiring more and / or less of a dose of antiscalant to prime the second priming period, and more importantly, an extended total duration of the second priming period.

[0061] In any case, the specific duration of the second priming period is based at least in part on the performance of the antiscalant introduced at the predetermined time and, optionally, the known presence of the antiscalant. Thus, the second priming period can be preset based at least in part on the performance of the selected antiscalant (and / or based on the presence of the antiscalant in the feed 309). Preferably, the selected antiscalant is such that the second priming period extends for at least half the duration / cycle of the first priming period, and preferably is equal to or longer than the duration of the first priming period. Thus, such an extended second priming period can result in a monotonic increase in permeate pressure to the rated permeate pressure limit of the at least one filtration membrane 311. Thus, the filtration system 300 can benefit if the filtration system 300 implements the at least one filtration membrane 311 as a high pressure filtration membrane module to allow the second priming period to extend to a time period that includes a relevant permeate pressure of, for example, 90-120 bar.

[0062] In an embodiment, the filtration system 300 implements a batch RO feature with a recovery rate set between 100% recovery and the non-scaling steady state, whether or not a scale inhibitor is used, for a portion of the cycle. Preferably, the filtration system 300 implements at least one filtration operation with a recovery rate set greater than the maximum non-scaling recovery rate and less than 100% recovery. This operation can be referred to herein as a substantially continuous operation, as the recovery rate can be set at a rate higher than the maximum non-scaling recovery rate, and with at least a portion of the feed water output as a retentate. In contrast, a continuous operation includes a recovery rate set equal to or less than the maximum non-scaling recovery rate, and a batch operation includes a recovery rate set at 100% (i.e., no retentate is discharged). Thus, a filtration system consistent with the present disclosure allows for a recovery rate higher than a similar continuous system and lower than a similar batch RO system, to achieve a balance of operating parameters such as total power consumption and sewer costs.

[0063] In an embodiment, the batch RO and continuous operation / cycle can be performed in a predetermined filtration operation sequence to achieve various end user requirements regarding, for example, total recovery (e.g., average over a predetermined amount of time), power consumption and related costs, such as sewer / disposal costs for disposal of the retentate water, as discussed above.

[0064] It should be noted that the above first and second priming periods are preferably maximized to extend the total amount of time that the batch operation is operated above the non-scaling steady state. However, other batch end parameters, such as concentration factor of the feed; feed quality, such as total dissolved solids (TDS), conductivity; permeate quality (such as permeate conductivity); and / or feed side pressure are also parameters that can trigger the end of a filtration process or otherwise can affect the total duration of the first / second priming periods.

[0065] Further, it should be noted that the filtration system 300 can use one or more energy recovery devices, such as a turbocharger or pressure exchanger, in conjunction with the various filtration processes disclosed herein to further increase power efficiency and reduce total power consumption.

[0066] In view of the foregoing, an aspect of the present disclosure is to determine optimal recovery rates and power consumption for RO and NF treatment recovery of scaling water by sequencing batch and / or continuous RO operations. Various features and aspects of the present disclosure preferably allow for enhancing / improving existing filtration systems to, for example, be able to better control and adjust power consumption and total recovery rates. However, the present disclosure is equally applicable to new filtration system designs, not necessarily limited to this point.

[0067] Figure 4 A plurality of example sequences (A-C) are shown, wherein Figure 3The operation of the filtration system 300 can include operating according to the sequences A, B, C, or any combination thereof, depending on, for example, desired overall recovery, power consumption, and retentate / retentate output. For example, the operation can include sequences A and B but not sequence C, or include sequences A and C but not sequence B.

[0068] During operation, each selected sequence can include performing each of the stages shown at times I, II, and III, or only a subset of these stages. For example, sequences A and C can be optionally performed without necessarily performing the flush stage at time III. Similarly, the sequences can be performed out of order, and sequence A can not necessarily be performed before B, and similarly C can not necessarily be performed after B, for example can be performed after A instead. The sequences can be repeated N times, such that a given sequence is repeated a predetermined number of times without other sequences in between. Thus, a particular combination of sequences can include one or more selected sequences, where the selected sequences are performed in a desired order, and preferably in an order that enables one or more performance goals, such as overall recovery and power consumption. The particular sequences can be preferably stored as machine-readable code (e.g., a settings file) in the memory (not shown) of the filtration system 300. Figure 3

[0069] It should be noted that sequence C allows for a continuous stage as a partial flush operation of the filtration system 300 following the batch stage at time (I), and is thus referred to herein as a partial flush, thus allowing for a reduction in the total number of operational cycles of the filtration system 300 relative to systems that perform a flush following each batch RO cycle. An example of this partial flush is shown and discussed below with reference to Figure 8 This partial flush can advantageously increase the operational life of the filtration system by reducing wear on the pumps and associated equipment, and reducing the period of time in which the filtration system is not outputting permeate (e.g., at 0% recovery). This also advantageously provides more stable operating conditions for the end user, as well as providing higher power efficiency for the filtration system by reducing energy losses caused by various filtration system components, such as current spikes / surges caused by cycling at least one pump 304. Such energy losses can significantly reduce the power efficiency of the filtration system, as such losses accumulate over the life of the system, and can ultimately represent a significant source of power loss, especially for large current motors in commercial / massive filtration systems.

[0070] Figure 5 An example process 500 is shown that illustrates various aspects and features of the present disclosure. In particular, the process 500 includes operations of causing a filtration system consistent with the present disclosure to perform a continuous operation / cycle, followed by performing a batch operation / cycle, for example as shown in Figure 4 ​as shown in example sequence A. However, process 500 is not necessarily limited to this and other sequences, and combinations of sequences are within the scope of the present disclosure.

[0071] Note that the operations of process 500 can not necessarily be performed in the order shown, and operations can be modified, omitted, and / or added according to various aspects and features disclosed herein without departing from the scope of the present disclosure. Preferably, process 500 is performed at least in part by controller 302 in conjunction with one or more components of filtration system 300 to enable automated operation, e.g., operation of filtration system 300 does not necessarily require manual control and / or intervention by a technician, e.g., to open / close at least one drain valve 308 and to cause at least one pump 304 to generate a target pressure.

[0072] However, process 500 can also be performed by manual operation, e.g., by a user manually actuating a switch to send a control signal thereto to actuate at least one drain valve 308 and / or filtration valve arrangement 312, or by a combination of automated steps and manual steps. For example, controller 302 can be configured to cause at least one pump to generate a target pressure via an automated sequence, while drain valve 308 can be manually actuated by a technician to achieve a desired recovery rate. Notably, controller 302 can be configured to cause a technician to perform one or more manual steps / processes, e.g., to actuate at least one drain valve 308, based on a timer / schedule, e.g., via a user interface of a computer system, a visual indicator such as an LED light, etc.

[0073] Process 500 begins at operation 502. In operation 502, controller 302 determines a first target recovery rate. Some non-limiting example recovery rates for the first target recovery rate include 25-50%, 50-70%, 50-80%, and all values and ranges therebetween. Preferably, the first target recovery rate is higher than a maximum non-fouling recovery rate of the filtration system, e.g., at least 80% recovery rate, and less than 100%. Additional non-limiting examples of the first target recovery rate include greater than a maximum non-fouling recovery rate of at least one filtration membrane and less than or equal to 98%. In any such case, the remaining feed water can be output as a retentate. For example, in the case where the first target recovery rate is greater than the maximum non-fouling recovery rate and less than or equal to 98%, at least 2% of the feed water is output as a retentate over a first time period. However, the first target recovery rate can also be selected to be equal to or less than the maximum non-fouling recovery rate of the filtration system in the case where steady state continuous operation of at least one cycle is desired.

[0074] In operation 504, the controller 302 causes the at least one bleed valve 308 to output a predetermined portion of the feed stream, e.g., feed stream 309, as retentate / trapped material, based on the first target recovery rate, over a first time period. For example, in an embodiment, a recovery rate of 80% is set as the first target recovery rate, and thus, the at least one bleed valve 308 can be configured to output 20% of the feed stream as retentate.

[0075] In operation 506, the controller 302 causes a drive signal (or first drive signal) to be provided to the at least one pump, e.g., pump 304, to cause it to produce an output permeate stream over a first time period based on the determined first target recovery rate. In an embodiment, the first drive signal is configured to cause the at least one pump to produce a substantially constant pressure such that over the first time period, the pressure increases by at most 10 psi per hour from an initial pressure that achieves the target recovery rate. In an embodiment, the first time period is 1-2 hours, and preferably at least 6 hours. Note that during substantially continuous operation, the rate of pressure change varies based on a plurality of factors including, for example, feed water characteristics and / or recovery rate set point. For example, during substantially continuous operation, a recovery rate of 99% would result in a relatively higher pressure increase per minute relative to operation at a 90% recovery rate. Thus, the example pressure values and rates of change provided herein in relation to substantially continuous operation are not provided for purposes of limitation.

[0076] In operation 508, the controller 302 determines a second target recovery rate. In an embodiment, the second target recovery rate is higher than the first target recovery rate. Some non-limiting embodiments of the second target recovery rate include a recovery rate between 70-80%, 80-100%, 90-100%, and all values and ranges therebetween. In an embodiment, the second target recovery rate is between 95-100%, and preferably 100%. In another embodiment, the second target recovery rate is lower than the first target recovery rate, wherein the second target recovery rate results in at least partial flushing of the at least one filtration membrane. For example, the second target recovery rate can be set to be equal to or lower than a maximum non-fouling recovery rate of the at least one filtration membrane 311, e.g., between 0-80%, and preferably higher than 0% to allow for continued production of permeate during partial flushing.

[0077] Alternatively, in addition, the second target recovery rate is less than or equal to a maximum non-fouling recovery rate of the at least one filtration membrane for a portion of the second time period, and greater than the maximum non-fouling recovery rate for a portion of the second time period.

[0078] In operation 510, the controller 302 causes the at least one bleed valve 308 to output a predetermined portion of the feed stream, e.g., the feed stream 309, as retentate, based on a second target recovery rate, over a second time period. In one example case, the second recovery rate is 100%, and thus the predetermined portion of the feed stream 309 output as retentate is zero (0%) or substantially zero (0%), such that up to and including 2% of the feed stream 309 is output as retentate. Thus, in this embodiment, the controller 302 causes the at least one bleed valve 308 to be closed, and causes substantially no portion of the feed stream 309 to be output as retentate over the second time period.

[0079] Alternatively, the second target recovery rate < 100%, and thus the predetermined portion of the feed stream 309 is proportional to the particular target recovery rate. For example, the second target recovery rate can be set between 96-100% to cause the volume ratio of feed water received to permeate stream output to be between 0.96-1.0 over the second time period. In another example, the second target recovery rate can be set between 0-80% as described above to cause at least partial flushing.

[0080] In operation 512, the controller 302 causes a drive signal (or second drive signal) to be provided to the at least one pump to produce an output permeate stream over a second time period based on the determined second target recovery rate. For example, the drive signal can be configured to cause the at least one pump to monotonically increase pressure during the second time period to exceed the osmotic pressure of the at least one filtration membrane (e.g., the at least one filtration membrane 311) of the system 300. Alternatively, the drive signal can be configured to cause flushing or partial flushing as described above. Further, the second drive signal can be configured to be substantially similar to the first drive signal as described above, the description and features of which will not be repeated for the sake of brevity. Figure 3

[0081] Preferably, the second drive signal is configured to cause the at least one pump to produce a substantially constant pressure such that the pressure increases by at least 10 psi per minute, preferably at least 50 psi per minute, over the second time period. In one embodiment, the second time period is at least two (2) minutes.

[0082] As discussed in greater detail below, operation 512 can further include the controller 302 introducing an antiscalant dose at a predetermined time to introduce a second priming period and extend the overall duration of the second time period, thereby increasing the overall recovery rate (e.g., the average recovery rate over time).

[0083] Figure 6 ​An example process 600 is shown to illustrate various aspects and features of this disclosure. In particular, process 600 includes operations that extend the batch RO cycle of a filtration system conforming to this disclosure (e.g., having a relevant recovery rate set above the maximum non-fouling recovery rate and below 100%, or preferably equal to 100%) by introducing a second initiation period. It should be noted that process 600 can be performed by any filtration system capable of performing batch RO processing and is not necessarily limited to one performed by a filtration system. Figure 3 The process is performed by the filtration system 300 and / or, for example, a filtration system having the aforementioned high-pressure filtration membrane module. However, preferably, the filtration system implementing process 600 includes a high-pressure filtration membrane module to allow the second initiation period to be extended until the osmotic pressure of the relevant filtration membrane reaches 90-120 bar or higher.

[0084] When, for example, as described above Figure 5 Process 600 may be executed when a drive signal is provided during operation 506 and / or 512 of process 500. However, process 600 is not limited in this respect, and process 600 may be executed by a filtering system without necessarily executing the operation of process 500. Note that the operation of process 600 may not necessarily be performed in the order shown, and operations may be modified, omitted, and / or added in accordance with various aspects and features disclosed herein without departing from the scope of this disclosure.

[0085] In operation 602, the controller 302 sets the recovery rate to be higher than the maximum non-fouling rate of at least one filter membrane (e.g., at least one filter membrane 311). In one embodiment, the recovery rate is between 90% and 99.99%, more preferably 100%.

[0086] In operation 604, controller 302 causes at least one pump to monotonically increase the pressure above the osmotic pressure of at least one filter membrane during a first time period. In operation 606, controller 302 determines a first predetermined moment within the first time period, the first predetermined moment being between the occurrence of fouling conditions and when fouling of at least one filter membrane occurs. In one embodiment, the predetermined moment is either at the initial start of the first time period or after the initial start of the first time period and before fouling and / or contamination of at least one filter membrane.

[0087] In operation 608, controller 302 introduces one or more antiscalant doses into at least one filter membrane at a predetermined time. In operation 610, controller 302 causes at least one pump to continuously and monotonically increase the pressure above the osmotic pressure of at least one membrane until a second predetermined time. The second predetermined time may be based on, for example, a fixed amount of time and / or on other conditions and factors to maintain the stability of the filtration system.

[0088] Figure 7To illustrate an example coordinate graph 700 of the operation of the filtration system 300 when the process procedures 500 and 600 of Figure 5 and Figure 6 are performed, respectively. The coordinate graph 700 includes a target recovery range along the Y-axis from 0% to 100%, and time along the X-axis. In this example sequence, the filtration system 300 operates at a first target recovery (e.g., 80%) for a first time period (TO to TO+1) in accordance with the operation 502-506 of the process procedure 500 of Figure 5 As shown, this first target recovery can be preferably selected as a ratio higher than a predetermined maximum non-scaling / polluting recovery of at least one filtration membrane 311 of the filtration system 300.

[0089] After the end of the first time period (e.g., TO+1), the filtration system 300 operates at a second target recovery (e.g., 98%) for a second time period (e.g., TO+1 to TO+2, or TO+1 to TO+3). The second time period defines at least a first priming period, where the first priming period is the time between the recovery of the filtration system 300 exceeding the non-scaling / polluting recovery (e.g., the recovery at which the onset of scaling / pollution conditions occurs) and the occurrence of scaling / pollution. In other words, during the second time period, the target recovery exceeds the maximum non-scaling recovery of the filtration system 300, and has an associated duration before the one or more filtration membranes reach a maximum non-scaling recovery state, which can also be referred to as a pre-antiscalant maximum non-scaling recovery state, without intentional injection of an antiscalant. As shown, the filtration system 300 reaches the pre-antiscalant maximum non-scaling recovery state only after TO+2 during the first priming period. Note that, as described above, an antiscalant can be present in the feed, and the term pre-antiscalant moment does not exclude the presence of such existing antiscalant.

[0090] As further shown, the filtration system 300, and more specifically the controller 302, can determine a predetermined moment, such as shown at TO+2, that is just before reaching the pre-antiscalant maximum non-scaling recovery state, e.g., when scaling / pollution occurs during the first priming period, e.g., based on the operation 606 of the process procedure 600 of Figure 6

[0091] At the predetermined moment, the controller 302 can initiate the injection of an antiscalant, e.g., based on the operation 608 of the process procedure 600 of Figure 6 ​Operation 608 of process 600 causes an antiscalant dose to be introduced / injected into at least one filtration membrane 311. In response, operation of filtration system 300 at the second target recovery rate can then continue during a second priming period until, for example, the permeate pressure of at least one filtration membrane 311 exceeds the maximum pressure of at least one pump 304, or until a predetermined maximum amount of time for operation of filtration system 300 during the second priming period has elapsed, to avoid operation of filtration system 300 under unstable conditions.

[0092] For example, therefore, introduction of antiscalant at the predetermined time extends the maximum non-scaling recovery state of filtration system 300 to T0+3, the shifted / extended recovery state also being referred to as the post-antiscalant maximum non-scaling recovery state. The duration of the extension can be such that, for example, the permeate pressure of at least one filtration membrane exceeds the maximum amount of pressure that can be generated by at least one pump 304 and / or the maximum pressure rating of the filtration membrane before the end of the second priming period (e.g., T0+3) is reached. Filtration system 300 can therefore preferably be configured to continue batch operation at the second target recovery rate during the second priming period for a predetermined maximum amount of time, wherein the predetermined maximum amount of time is less than the total duration of the second priming period provided by introduction of the antiscalant dose at the predetermined time. The predetermined maximum amount of time can be selected as a constant duration, e.g., 1 minute, 3 minutes, 1-30 minutes, or can be dynamically set based on, for example, the dose of antiscalant, and / or known antiscalant performance ratings, and / or known feed conditions, pressure, or other equipment limitations, and / or permeate or retentate mass requirements (which can be measured online by, for example, Internet of Things (IOT) devices).

[0093] In any such case, as Figure 7 illustrated, the predetermined time separates the first priming period and the second priming period. Note that the first priming period and the second priming period can be substantially equal in duration, or can be different. Preferably, the second priming period is at least half the duration of the first priming period.

[0094] Figure 8 To illustrate an example coordinate plot 800 of operation of filtration system 300 when performing process 500 according to an embodiment. Figure 5 Coordinate plot 800 includes target recovery rate along the Y-axis from 0% to 100%, and time along the X-axis. In this example case, filtration system 300 is operated in a sequence that includes substantially continuous operation at a first recovery rate target (higher than the maximum non-scaling recovery rate and lower than 100% recovery rate) and batch operation at a second recovery rate target (100% recovery rate). The sequence also includes optional flush cycles, as described below.

[0095] As shown, the total duration of each substantially continuous operation is Di, and the total duration of each batch operation is D2. Di can be counted in at least 6 hours, preferably Di is counted in at least one day. On the other hand, D2 can be counted in at least one minute to several hours, preferably at least 5 minutes. Thus, the duration of Di can be significantly longer relative to D2.

[0096] The duration Di of each substantially continuous operation can be uniform, or can vary such that each operation is longer, substantially equal, or shorter than other substantially continuous operations. Likewise, the duration D2 of each batch operation can be uniform, or can vary such that each operation is longer, substantially equal, or shorter than other batch operations. As noted above, an antiscalant can be introduced at a predetermined time to introduce / trigger a second initiation period. Thus, one or more batch operations can include a duration D2 that is longer than other batch operations that do not include the use of an antiscalant to achieve a second initiation period.

[0097] As further shown, the filtration system 300 can be operated at a recovery rate of 0% to cause an optional (full) flush of the at least one filtration membrane 311 such that all of the received feed water is output as a retentate. The optional flush can be caused by, for example, a second drive signal, as described above with respect to the process 500 of Figure 5 However, the optional flush can also be caused by a third drive signal. Preferably, the third drive signal is configured to cause a third target recovery rate, for example, 0% in the case of a full flush, or greater than zero (0%) and less than or equal to a maximum non-scaling recovery rate (e.g., 80%) in the case of a partial flush. In embodiments, the third target recovery rate can be different than the first target recovery rate and the second target recovery rate, as described above with respect to the process 500 of Figure 5

[0098] For example, as shown, within a third period (or duration) D3 based on the third drive signal, the filtration system 300 can be operated at a recovery rate that is less than the maximum non-scaling / fouling recovery rate, for example, between 1-80%, preferably at a recovery rate of 80%. The duration D3 is designed to cause at least a partial flush of the at least one filtration membrane 311 without necessarily a full flush (e.g., 0% recovery rate flush for a period of time). Thus, the filtration system 300 can continue to produce a permeate stream without intervening full flushes, that is, for example, without having to be reduced to 0% recovery rate to flush after a batch RO operation.

[0099] ​Accordingly, aspects of the present disclosure enable NF / RO designers to select the optimal method of operation that combines selected elements of continuous and batch NF / RO based on constraints of the end user facility and reduce the long term operating cost of the plant. Methods for extending batch operation to a second initiation period that allows for higher water recovery by injecting an antiscalant are also disclosed herein. Furthermore, in addition to scaling, the techniques and features disclosed herein can also be used for contamination management, as contamination similarly has a negative impact on pressure and recovery of NF / RO systems.

[0100] Other example aspects and structures

[0101] One aspect of the present disclosure includes a method of determining recovery and power conditions / parameters (also referred to herein as operating parameters) that allow a NF / RO system to operate at a set point that falls along a continuum between two extremes of non-scaling steady state operation (with or without antiscalant) provided by a continuous system and 100% recovery batch operation provided by an RO system in a general sense. Accordingly, the following disclosure provides the following non-limiting embodiments.

[0102] Embodiment 1 includes operating a NF / RO system having at least one feed stream, one reject stream, and one permeate stream, wherein for at least a portion of an operating cycle, the recovery is set between 100% recovery and an extreme of maximum non-scaling or non-contaminating recovery.

[0103] Embodiment 2 includes operating a NF / RO system having at least one feed stream, one reject stream, and one permeate stream, wherein for at least a portion of an operating cycle, the recovery is set between 100% recovery and an extreme of maximum non-scaling or non-contaminating recovery, and a feed flush sequence is implemented as a final step of the operating cycle prior to repeating the operating cycle. (See, e.g., Sequence B in Figure 4

[0104] Embodiment 3 includes a method of operating a NF / RO system having at least one feed stream, one reject stream, and one permeate stream, wherein for a portion of an operating cycle, the recovery is set between 100% recovery and an extreme of maximum non-scaling or non-contaminating recovery, and for another portion of the operating cycle, the recovery is 100%. (See, e.g., Sequences A and C in Figure 4

[0105] ​​Embodiment 4 is a method of operating an NF / RO system having at least one feed stream, one reject stream, and one permeate stream, wherein for a portion of the operating cycle, the recovery is set between 100% recovery and the extreme of the maximum non-fouling or non-fouled recovery, for another portion of the operating cycle, the recovery is 100%, and prior to repeating the operating cycle, a feed flush sequence is performed as the last step of the operating cycle. (See, e.g., FIGS. 1A and 1C of Sequence A and C). Figure 4

[0106] Embodiment 5 is a method of operating an NF / RO system having at least one feed stream, one reject stream, and one permeate stream, wherein for at least a portion of the operating cycle, the recovery is set between 100% recovery and the extreme of the maximum non-fouling or non-fouled recovery, and for a first priming period, the operation is initially performed without the use of a scale inhibitor until just prior to the point at which fouling / pollution occurs, and then one or more doses of scale inhibitor are added to the feed so as to extend the operation (e.g., a second priming period) just prior to the completion of a feed flush sequence as the last step of the operating cycle before repeating the operating cycle one or more times.

[0107] Embodiment 6 is a method of operating an NF / RO system having at least one feed stream, one reject stream, and one permeate stream, wherein for a portion of the operating cycle, the recovery is set between 100% recovery and the extreme of the maximum non-fouling or non-fouled recovery, for another portion of the operating cycle, the recovery is 100%, and for a first priming period, the operation is initially performed without the use of a scale inhibitor until just prior to the point at which the scale inhibitor priming period (or second priming period) is reached, and then a dose of scale inhibitor is added to the feed so as to extend the operation (e.g., a second priming period) just prior to the completion of a feed flush sequence as the last step of the operating cycle before repeating the operating cycle.

[0108] Embodiment 7 is a method of operating an NF / RO system having at least one feed stream and one permeate stream, wherein the recovery is 100%, and for a first priming period, the operation is initially performed without the use of a scale inhibitor until just prior to the point at which the scale inhibitor priming period (second priming period) is reached, and then a dose of scale inhibitor is added to the feed so as to extend the operation (second priming period) just prior to the completion of a feed flush sequence as the last step of the operating cycle before repeating the operating cycle.

[0109] ​Embodiment 8 is a method of operating an NF / RO system having at least one feed stream and one permeate stream, wherein the recovery is 100%, operated with scale inhibitor, such that the concentration is allowed to exceed the scale inhibitor-free run-in period, until just before the scale inhibitor run-in period, before the completion of the feed flush sequence as the last step of the operating cycle, before repeating the operating cycle.

[0110] Embodiment 9 is a method of operating an NF / RO system having plate-and-frame or spacer-tube high pressure membrane modules, having at least one feed stream and one permeate stream, wherein the recovery is 100%, operated initially without scale inhibitor, until just before the scale inhibitor-free run-in period, then adding a dose of scale inhibitor to the feed, such that the operation is extended (second run-in period) until the scale inhibitor run-in period, just before the completion of the feed flush sequence as the last step of the operating cycle, before repeating the operating cycle.

[0111] Embodiment 10 is a method of operating an NF / RO system having plate-and-frame or spacer-tube high pressure membrane modules, having at least one feed stream and one permeate stream, wherein the recovery is 100%, operated with scale inhibitor, such that the concentration is allowed to exceed the scale inhibitor-free run-in period, until just before the scale inhibitor run-in period, before the completion of the feed flush sequence as the last step of the operating cycle, before repeating the operating cycle.

[0112] Embodiment 11 is a method of operating a filtration system having at least one inlet fluidically coupled to at least one feed stream, at least one filtration membrane fluidically coupled to the at least one inlet to receive feed water from the at least one feed stream, and at least one pump for generating pressure to transfer the feed water from the at least one feed stream to the at least one filtration membrane and produce an output permeate stream, the method comprising causing a first drive signal to be provided to the at least one pump such that the generated pressure produces the output permeate stream at a recovery rate substantially equal to a first target recovery rate for a first time period, the first target recovery rate being greater than a maximum non-scaling recovery rate of the at least one filtration membrane and less than 100%.

[0113] Embodiment 12 includes the features of Embodiment 11 and further comprises causing a second drive signal to be provided to the at least one pump such that the generated pressure produces the output permeate stream at a recovery rate substantially equal to a second target recovery rate for a second time period.

[0114] Embodiment 13 includes the features of Embodiment 12, wherein the second target recovery rate is equal to or less than the maximum non-scaling recovery rate of the at least one filtration membrane.

[0115] Embodiment 14 includes the features of Embodiment 12, wherein the second target recovery is greater than the maximum non-fouling recovery of the at least one filtration membrane.

[0116] Embodiment 15 includes the features of Embodiment 12, wherein the second target recovery is greater than the maximum non-fouling recovery of the at least one filtration membrane and the first target recovery.

[0117] Embodiment 16 includes the features of Embodiment 12, wherein the second drive signal is configured to cause at least partial flushing of the at least one filtration membrane such that the second target recovery is less than the maximum non-fouling recovery of the at least one filtration membrane.

[0118] Embodiment 17 includes the features of Embodiment 16, wherein the second target recovery is equal to zero such that all of the received feed water of the at least one feed stream is output as retentate.

[0119] Embodiment 18 includes the features of Embodiment 12, wherein the second target recovery is less than or equal to the maximum non-fouling recovery of the at least one filtration membrane for a portion of the second time period and is higher than the maximum non-fouling recovery for a portion of the second time period.

[0120] Embodiment 19 includes the features of Embodiment 12, wherein the second target recovery is greater than 0% and less than or equal to the maximum non-fouling recovery to cause partial flushing of the at least one filtration membrane.

[0121] Embodiment 20 includes the features of Embodiment 12, wherein the second target recovery is between 96-100% such that the volume ratio of received feed water to output permeate stream is between 0.96-1.0 for the second time period.

[0122] Embodiment 21 includes the features of Embodiment 12, and further includes fluidly coupling at least one bleed valve to the at least one filtration membrane to output a first predetermined portion of the feed water of the at least one feed stream as retentate water for the second time period.

[0123] Embodiment 22 includes the features of Embodiment 21, wherein the second target recovery is equal to 100%, and wherein causing the at least one bleed valve to output the first predetermined portion of the feed water of the at least one feed stream as retentate water for the second time period further includes closing the at least one bleed valve such that substantially 0% of the at least one feed stream is output as retentate water.

[0124] Embodiment 23 includes the features of Embodiment 21, wherein the second target recovery is less than 100%, and wherein causing the at least one bleed valve to output the first predetermined portion of the feed water of the at least one feed stream as retentate water for the second time period further includes opening the at least one bleed valve to output the first predetermined portion of the feed water as waste water.

[0125] Embodiment 24 includes the features of Embodiment 12, wherein the second target recovery is 100% such that 0% of the at least one feed stream is output as reject water for at least a portion of the second time period.

[0126] Embodiment 25 includes the features of Embodiment 12, wherein the second time period occurs before or after the first time period based on a predetermined order of filtration operations.

[0127] Embodiment 26 includes the features of Embodiment 12, wherein the second target recovery is 100%, and causing the second drive signal to be provided to the at least one pump further includes introducing one or more doses of antifouling agent into the at least one filtration membrane at a predetermined time within the second time period, and wherein the predetermined time divides the second time period into a first induction period occurring before the predetermined time and a second induction period occurring after the predetermined time of introducing the antifouling agent, the first induction period being a period of operation before the at least one filtration membrane experiences fouling and / or contamination, the second induction period being a measured period of time from when the antifouling agent is introduced to when the at least one filtration membrane experiences fouling and / or contamination.

[0128] Embodiment 27 includes the features of any of Embodiments 11-26, and further includes causing a third drive signal to be provided to the at least one pump to at least partially flush the at least one filtration membrane, wherein causing the third drive signal to be provided to the at least one pump to at least partially flush the at least one filtration membrane further includes causing the third drive signal to be provided to the at least one pump for a third time period, the third time period being after the second time period.

[0129] Embodiment 28 includes the features of Embodiment 27, wherein the third drive signal is configured to cause the at least one pump to generate pressure to produce an output permeate stream at a recovery rate substantially equal to a third target recovery for the third time period.

[0130] Embodiment 29 includes the features of Embodiment 28, wherein the third target recovery is between 0-80% for the third time period to result in a partial flush of the at least one filtration membrane.

[0131] Embodiment 30 includes the features of Embodiment 28, wherein the third target recovery is substantially 0% to result in a complete flush of the at least one filtration membrane, the third target recovery being different from the first target recovery and the second target recovery.

[0132] Embodiment 31 includes the features of any of Embodiments 11-30, wherein the second time period is after the first time period, and wherein causing the second drive signal to be provided for the second time period does not result in an intervening complete flush of the at least one filtration membrane between the first time period and the second time period.

[0133] Embodiment 32 includes the features of Embodiment 12, wherein the second drive signal is configured to cause the pressure generated by the at least one pump to increase by an amount that exceeds the osmotic pressure of the at least one filtration membrane to cause the pressure to increase by at least 10 psi per minute for a second time period of at least two (2) minutes.

[0134] Embodiment 33 includes the features of Embodiment 12, wherein the second drive signal is configured to cause the at least one pump to generate a substantially constant pressure to cause the substantially constant pressure to increase by at most 10 pounds per square inch (psi) per hour for a second time period of at least 6 hours.

[0135] Embodiment 34 includes the features of any one of Embodiments 11-33, wherein the first drive signal is configured to cause the pressure generated by the at least one pump to increase by an amount that exceeds the osmotic pressure of the at least one filtration membrane to cause the pressure to increase by at least 10 psi per minute for a first time period of at least two (2) minutes.

[0136] Embodiment 35 includes the features of any one of Embodiments 11-33, wherein the first drive signal is configured to cause the at least one pump to generate a substantially constant pressure to cause the substantially constant pressure to increase by at most 10 pounds per square inch (psi) per hour for a first time period of at least 6 hours.

[0137] Embodiment 36 includes the features of any one of Embodiments 11-35, further comprising fluidly coupling the at least one bleed valve to the at least one filtration membrane to output a second predetermined portion of the feed water of the at least one feed stream as retentate water for the first time period.

[0138] Embodiment 37 includes the features of Embodiment 36, wherein the first target recovery is less than or equal to 98%, and wherein fluidly coupling the at least one bleed valve to the at least one filtration membrane to output a second predetermined portion of the feed water of the at least one feed stream as retentate water for the first time period further comprises opening the at least one bleed valve to cause at least 2% of the feed water of the at least one feed stream to be output as retentate water for the first time period.

[0139] Embodiment 38 includes the features of any one of Embodiments 11-37, wherein causing the first drive signal to be provided to the at least one pump further comprises causing one or more antiscalant doses to be introduced to the at least one filtration membrane at a predetermined time during the first time period, the predetermined time being at or after an initial start of the first time period and before a time at which the at least one filtration membrane is scaled and / or fouled.

[0140] Embodiment 39 includes the features of Embodiment 38, wherein the first time period is divided by a predetermined time into a first induction period occurring before the predetermined time and a second induction period occurring after the predetermined time of introducing the scale inhibitor, the first induction period being a time period of operation before the at least one filtration membrane experiences fouling and / or contamination, the second induction period being a measured time period from the introduction of the scale inhibitor to the at least one filtration membrane experiencing fouling and / or contamination.

[0141] Embodiment 40 includes the features of Embodiment 39, wherein causing the first drive signal to be provided to the at least one pump further includes causing the at least one pump to monotonically increase pressure above an osmotic pressure of the at least one filtration membrane from the predetermined time of introducing the scale inhibitor to maintain the first target recovery rate for at least a portion of the second induction period.

[0142] Embodiment 41 is a filtration system including at least one inlet fluidically coupled to at least one feed stream, at least one filtration membrane fluidically coupled to the at least one inlet to receive feed water from the at least one feed stream, at least one pump to generate pressure to transfer the feed water from the at least one feed stream to the at least one filtration membrane and to generate an output permeate stream, and a controller configured to cause a first drive signal to be provided to the at least one pump to cause the generated pressure to generate the output permeate stream at a recovery rate substantially equal to a first target recovery rate for a first time period, the first target recovery rate being greater than a maximum non-fouling recovery rate of the at least one filtration membrane and less than 100%.

[0143] Embodiment 42 includes the features of Embodiment 41, wherein the controller is further configured to cause a second drive signal to be provided to the at least one pump to cause the generated pressure to generate the output permeate stream at a recovery rate substantially equal to a second target recovery rate for a second time period.

[0144] Embodiment 43 includes the features of Embodiment 42, wherein the second target recovery rate is equal to or less than the maximum non-fouling recovery rate of the at least one filter.

[0145] Embodiment 44 includes the features of Embodiment 42, wherein the second target recovery rate is greater than the maximum non-fouling recovery rate of the at least one filtration membrane.

[0146] Embodiment 45 includes the features of Embodiment 42, wherein the second target recovery rate is greater than the maximum non-fouling recovery rate of the at least one filtration membrane and the first target recovery rate.

[0147] Embodiment 46 includes the features of Embodiment 42, wherein the second drive signal is configured to cause at least a partial flush of the at least one filtration membrane.

[0148] Embodiment 47 includes the features of Embodiment 46, wherein the second target recovery is equal to zero, such that all of the feed water of the at least one feed stream is output as retentate.

[0149] Embodiment 48 includes the features of Embodiment 46, wherein the second target recovery is less than or equal to a maximum non-fouling recovery of the at least one filtration membrane for a portion of the second time period, greater than the maximum non-fouling recovery for a portion of the second time period.

[0150] Embodiment 49 includes the features of Embodiment 46, wherein the second target recovery is greater than 0% and less than the maximum non-fouling recovery, to result in partial flushing of the at least one filtration membrane.

[0151] Embodiment 50 includes the features of Embodiment 42, wherein the second target recovery is between 96-100%, such that a volume ratio of feed water received to output permeate stream is between 0.96-1.0 for the second time period.

[0152] Embodiment 51 includes the features of Embodiment 42, further comprising at least one bleed valve fluidically coupled to the at least one filtration membrane to output a first predetermined portion of the feed water of the at least one feed stream as retentate water for the second time period.

[0153] Embodiment 52 includes the features of Embodiment 51, wherein the second target recovery is equal to 100%, and wherein the controller is configured to cause the at least one bleed valve to close, such that the first predetermined portion of the feed water output as retentate water for the second time period is zero.

[0154] Embodiment 53 includes the features of Embodiment 51, wherein the second target recovery is 100%, such that 0% of the at least one feed stream is output as retentate water for the second time period.

[0155] Embodiment 54 includes the features of Embodiment 51, wherein the second time period occurs before or after the first time period based on a predetermined order of filtration operations stored in the memory.

[0156] Embodiment 55 includes the features of any one of Embodiments 42-54, wherein the second drive signal is further configured to cause one or more antifouling agent doses to be introduced into the at least one filtration membrane at predetermined times for the second time period.

[0157] Embodiment 56 includes the features of Embodiment 55, wherein the second time period is divided by a predetermined time into a first induction period occurring before the predetermined time and a second induction period occurring after the predetermined time of introducing the scale inhibitor, the first induction period being a time period of operation before scale and / or fouling occurs on the at least one filtration membrane, the second induction period being a measured time period from when the scale inhibitor is introduced to when scale and / or fouling occurs on the at least one filtration membrane.

[0158] Embodiment 57 includes the features of any one of Embodiments 42-56, wherein the controller is further configured to cause the third drive signal to be provided to the at least one pump to cause at least partial flushing over a third time period, the third time period being after the second time period.

[0159] Embodiment 58 includes the features of Embodiment 57, wherein the third drive signal is configured to cause the at least one pump to generate a pressure to produce an output permeate flow over the third time period at a recovery rate substantially equal to a third target recovery rate, the third target recovery rate being different from the first target recovery rate and the second target recovery rate.

[0160] Embodiment 59 includes the features of any one of Embodiments 57-58, wherein the third target recovery rate is between 0-80% over the third time period to cause partial flushing of the at least one filtration membrane.

[0161] Embodiment 60 includes the features of any one of Embodiments 57-58, wherein the third recovery rate is substantially 0% to cause complete flushing of the at least one filtration membrane.

[0162] Embodiment 61 includes the features of any one of Embodiments 42-60, wherein the second time period is after the first time period, and wherein the second drive signal is caused to be provided over the second time period without causing an intervening complete flushing of the at least one filtration membrane between the first time period and the second time period.

[0163] Embodiment 62 includes the features of Embodiment 42, wherein the second drive signal is configured to cause the pressure generated by the at least one pump to increase to an amount that exceeds an osmotic pressure of the at least one filtration membrane such that the pressure increases by at least 10 pounds per square inch (psi) per minute over a second time period, the second time period being at least two (2) minutes.

[0164] Embodiment 63 includes the features of Embodiment 42, wherein the second drive signal is configured to cause the at least one pump to generate a substantially constant pressure such that the substantially constant pressure increases by at most 10 pounds per square inch (psi) per hour over a second time period, the second time period being at least 6 hours.

[0165] Embodiment 64 includes the features of any of embodiments 41-63, wherein the first drive signal is configured to cause the pressure generated by the at least one pump to increase by an amount that exceeds the osmotic pressure of the at least one filtration membrane such that, for a first time period, the pressure increases by at least 10 psi per minute, the first time period being at least two (2) minutes.

[0166] Embodiment 65 includes the features of any of embodiments 41-63, wherein the first drive signal is configured to cause the at least one pump to generate a substantially constant pressure such that, for a first time period, the substantially constant pressure increases by at most 10 pounds per square inch (psi) per hour, the first time period being at least 6 hours.

[0167] Embodiment 66 includes the features of any of embodiments 41-65, further comprising at least one bleed valve fluidically coupled to the at least one filtration membrane to output a second predetermined portion of the feed water of the at least one feed stream as retentate for the first time period.

[0168] Embodiment 67 includes the features of embodiment 66, wherein the first target recovery is less than or equal to 98%, the first predetermined portion of the feed water is at least 2%, and wherein the controller is configured to cause the at least one bleed valve to output the first predetermined portion of the feed water of the at least one feed stream as retentate for the first time period.

[0169] Embodiment 68 includes the features of any of embodiments 41-67, wherein the controller is further configured to cause one or more antiscalant doses to be introduced into the at least one filtration membrane at a predetermined time within the first time period.

[0170] Embodiment 69 includes the features of embodiment 68, wherein the predetermined time divides the first time period into a first induction period occurring before the predetermined time and a second induction period occurring after the predetermined time at which the antiscalant is introduced, the first induction period being a period of operation before the at least one filtration membrane experiences fouling and / or contamination, the second induction period being a measured period of time from when the antiscalant is introduced to when the at least one filtration membrane experiences fouling and / or contamination.

[0171] Embodiment 70 includes the features of embodiment 69, wherein causing the first drive signal to be provided to the at least one pump further comprises causing the at least one pump to monotonically increase the pressure beyond the osmotic pressure of the at least one filtration membrane from the predetermined time at which the antiscalant is introduced to maintain the first target recovery for at least a portion of the second induction period.

[0172] Embodiment 71 includes the features of any of embodiments 41-70, wherein the at least one filtration membrane comprises at least one high pressure filtration membrane having a pressure shell capable of withstanding a pressure of at least 90 bar.

[0173] Embodiment 72 includes the features of any of embodiments 41-71, wherein the at least one filtration membrane includes at least a first filtration membrane and a second filtration membrane, each of the first and second filtration membranes providing at least a portion of a first filtration stage and a second filtration stage, respectively.

[0174] Embodiment 73 includes the features of embodiment 72, further comprising a filtration valve arrangement to switchably fluidly couple the first filtration membrane and / or the second filtration membrane to the at least one feed stream.

[0175] Embodiment 74 includes the features of embodiment 73, wherein the controller is further configured to cause the filtration valve arrangement to switchably fluidly couple the first filtration membrane and / or the second filtration membrane to the at least one feed stream for the first time period and / or the second time period.

[0176] Embodiment 75 includes the features of any of embodiments 41-74, wherein the at least one inlet is fluidly coupled to a drain of the filtration system such that the at least one feed stream includes a concentrate from the filtration system.

[0177] Embodiment 76 includes the features of any of embodiments 41-74, wherein the at least one inlet is fluidly coupled to an outlet of the filtration system such that the at least one feed stream includes a permeate output by the filtration system.

[0178] Embodiment 77 is a method for operating a filtration system having an inlet fluidly coupled to at least one feed stream, at least one filtration membrane fluidly coupled to the inlet to receive feed water of the at least one feed stream, and at least one pump for generating a pressure to transfer the feed water of the at least one feed stream into the at least one filtration membrane and to generate an output permeate stream, the method comprising causing a first drive signal to be provided to the at least one pump, wherein the first drive signal increases the generated pressure of the at least one pump to an amount that exceeds an osmotic pressure of the at least one filtration membrane, and maintaining a target recovery rate that exceeds a maximum non-fouling recovery rate and has an associated duration of time before reaching a maximum non-fouling recovery rate condition of the at least one filtration membrane for a first time period; detecting when the maximum non-fouling recovery rate condition of the at least one filtration membrane is reached during the first time period; and in response to detecting that the maximum non-fouling recovery rate condition is reached, causing one or more antifouling agent doses to be introduced into the at least one filtration membrane to increase an amount of time between when the maximum non-fouling recovery rate condition is reached and when fouling and / or contamination of the at least one filtration membrane occurs.

[0179] Embodiment 78 is a method for operating a batch reverse osmosis (RO) filtration system having an inlet fluidically coupled to at least one feed stream, at least one filtration membrane fluidically coupled to the inlet to receive feed water of the at least one feed stream, and at least one pump for generating pressure to transfer the feed water of the at least one feed to the at least one filtration membrane and to generate an output permeate stream, the method comprising causing a first drive signal to be provided to the at least one pump to cause output of the output permeate stream at a target recovery rate that is greater than a maximum non-fouling recovery rate of the at least one filtration membrane for a first time period, and the first drive signal increasing the generated pressure of the at least one pump to an amount that exceeds a permeate pressure of the at least one filtration membrane to maintain output of the output permeate stream at the target recovery rate, and introducing one or more antifouling agent doses into the at least one filtration membrane at a predetermined time within the first time period.

[0180] Embodiment 79 includes the features of Embodiment 78, wherein the predetermined time divides the first time period into a first induction period occurring before the predetermined time and a second induction period occurring after the predetermined time of introducing the one or more antifouling agent doses, the first induction period being a time period of operation before fouling and / or contamination occurs, and the second induction period being a measured time period from when the one or more antifouling agent doses are introduced to when fouling and / or contamination occurs.

[0181] Embodiment 80 is a non-transitory computer readable medium having stored thereon a plurality of instructions that cause the method of Embodiment 77 to be performed. Embodiment 81 is a non-transitory computer readable medium having stored thereon a plurality of instructions that cause the method of any one of Embodiments 78-79 to be performed.

[0182] Embodiment 82 is a non-transitory computer readable medium having stored thereon a plurality of instructions that cause the method of any one of Embodiments 1-40 to be performed.

[0183] While principles of the present disclosure have been described herein, it is to be understood that the description is merely exemplary and not intended to limit the scope of the present disclosure. Other embodiments within the scope of the present disclosure are possible. Those skilled in the art will appreciate variations from the teachings herein and it is intended that the present disclosure cover such variations as fall within the scope of the claims. Modifications and alternatives are contemplated to fall within the scope of the present disclosure as defined by the following claims, other than as limited to the scope of the disclosure.

Claims

1. A filtration system, comprising: At least one inlet, the at least one inlet fluidly coupled to at least one feed flow; At least one filter membrane, the at least one filter membrane being fluidly coupled to the at least one inlet to receive feed water from the at least one feed stream; At least one pump, the at least one pump being used to generate pressure to transfer feed water from the at least one feed stream into the at least one filter membrane in the future, and to generate an output permeate stream; and The controller is configured as follows: A first drive signal is provided to the at least one pump such that the resulting pressure produces the output permeate stream at a recovery rate substantially equal to a first target recovery rate over a first time period, the first target recovery rate being greater than the maximum non-fouling recovery rate of the at least one filter membrane and less than 100%, wherein the maximum non-fouling recovery rate is the water recovery rate at the onset of fouling, or when supersaturation of the fouling compound of interest first occurs. One or more antiscalant doses are introduced into the at least one filter membrane at predetermined times within the first time period, wherein the predetermined times divide the first time period into a first initiation period occurring before the predetermined times and a second initiation period occurring after the predetermined times of antiscalant introduction, the first initiation period being the time period before scaling and / or fouling occurs in the at least one filter membrane, and the second initiation period being the time period measured from the introduction of the antiscalant to the time when scaling and / or fouling occurs in the at least one filter membrane.

2. The filtration system according to claim 1, wherein, The controller is further configured to provide a second drive signal to the at least one pump, such that the resulting pressure generates the output permeate stream at a recovery rate substantially equal to the second target recovery rate during a second time period.

3. The filtration system according to claim 2, wherein, The second target recovery rate is equal to or less than the maximum non-fouling recovery rate of the at least one filter.

4. The filtration system according to claim 2, wherein, The second target recovery rate is greater than the maximum non-fouling recovery rate of the at least one filter membrane.

5. The filtration system according to claim 2, wherein, The second target recovery rate is greater than the maximum non-fouling recovery rate of the at least one filter membrane and the first target recovery rate.

6. The filtration system according to claim 2, wherein, The second drive signal is configured to cause at least a partial flushing of the at least one filter membrane.

7. The filtration system according to claim 6, wherein, The second target recovery rate is zero, such that all feed water from the at least one feed stream is output as retentate.

8. The filtration system according to claim 6, wherein, The second target recovery rate is less than or equal to the maximum non-fouling recovery rate of the at least one filter membrane during a portion of the second time period, and greater than the maximum non-fouling recovery rate during a portion of the second time period.

9. The filtration system according to claim 6, wherein, The second target recovery rate is greater than 0% and less than the maximum non-fouling recovery rate, resulting in partial flushing of the at least one filter membrane.

10. The filtration system according to claim 2, wherein, The second target recovery rate is between 96% and 100%, such that the volume ratio of the feed water received to the output permeate stream during the second time period is between 0.96 and 1.

0.

11. The filtration system of claim 2, further comprising at least one drain valve, the at least one drain valve being fluidly coupled to the at least one filter membrane to output a first predetermined portion of the feed water of the at least one feed stream as truncation water during the second time period.

12. The filtration system according to claim 11, wherein, The second target recovery rate is equal to 100%, and the controller is configured to close the at least one discharge valve so that the first predetermined portion of the feed water output as truncation water during the second time period is zero.

13. The filtration system according to claim 11, wherein, The second target recovery rate is 100%, such that 0% of the at least one feed stream is output as truncation water during the second time period.

14. The filtration system according to claim 11, wherein, Based on a predetermined order of filtering operations stored in memory, the second time period occurs before or after the first time period.

15. The filtration system according to claim 2, wherein, The second drive signal is further configured to introduce one or more antiscalant doses into the at least one filter membrane at a predetermined time within the second time period. The predetermined time period divides the second time period into a first initiation period that occurs before the predetermined time period and a second initiation period that occurs after the predetermined time period when the scale inhibitor is introduced. The first initiation period is the time period before scaling and / or fouling of the at least one filter membrane occurs, and the second initiation period is the time period measured from the introduction of the scale inhibitor to the time when scaling and / or fouling of the at least one filter membrane occurs.

16. The filtration system according to claim 2, wherein, The controller is further configured to provide a third drive signal to the at least one pump to cause at least partial flushing during a third time period, which follows the second time period.

17. The filtration system according to claim 16, wherein, The third drive signal is configured to cause the at least one pump to generate pressure to produce the output permeate stream at a recovery rate substantially equal to the third target recovery rate during the third time period, the third target recovery rate being different from the first target recovery rate and the second target recovery rate.

18. The filtration system according to claim 16, wherein, During the third time period, the third target recovery rate is between 0% and 80%, resulting in at least partial flushing of the at least one filter membrane.

19. The filtration system according to claim 17, wherein, The third target recovery rate is essentially 0% to result in complete flushing of the at least one filter membrane.

20. The filtration system according to claim 2, wherein, The second time period is after the first time period, and the second drive signal is provided during the second time period without causing interim complete rinsing of the at least one filter membrane between the first and second time periods.

21. The filtration system according to claim 2, wherein, The second drive signal is configured to increase the pressure generated by the at least one pump by an amount exceeding the osmotic pressure of the at least one filter membrane, such that the pressure increases by at least 10 pounds per square inch per minute during the second time period, which is at least two minutes.

22. The filtration system according to claim 2, wherein, The second drive signal is configured to cause the at least one pump to generate a substantially constant pressure such that the substantially constant pressure increases by a maximum of 10 pounds per square inch per hour during the second time period, which is at least 6 hours.

23. The filtration system according to claim 1, wherein, The first drive signal is configured to increase the pressure generated by the at least one pump by an amount exceeding the osmotic pressure of the at least one filter membrane, such that the pressure increases by at least 10 pounds per square inch per minute during the first time period, which is at least two minutes.

24. The filtration system according to claim 1, wherein, The first drive signal is configured to cause the at least one pump to generate a substantially constant pressure such that the substantially constant pressure increases by a maximum of 10 pounds per square inch per hour during the first time period, which is at least 6 hours.

25. The filtration system of claim 1, further comprising at least one drain valve, the at least one drain valve being fluidly coupled to the at least one filter membrane to output a second predetermined portion of the feed water of the at least one feed stream as truncation water during the first time period.

26. The filtration system according to claim 25, wherein, The first target recovery rate is less than or equal to 98%, the first predetermined portion of the feed water is at least 2%, and wherein the controller is configured to cause the at least one discharge valve to output the first predetermined portion of the feed water of the at least one feed stream as truncation water during the first time period.

27. The filtration system according to claim 1, wherein, Providing the first drive signal to the at least one pump also includes causing the at least one pump to monotonically increase the pressure above the osmotic pressure of the at least one filter membrane from the predetermined moment when the antiscalant is introduced, in order to maintain the first target recovery rate for at least a portion of the second initiation period.

28. The filtration system according to claim 1, wherein, The at least one filter membrane includes at least one high-pressure filter membrane having a pressure housing capable of withstanding a pressure of at least 90 bar.

29. The filtration system according to claim 1, wherein, The at least one filter membrane includes at least a first filter membrane and a second filter membrane, each of the first filter membrane and the second filter membrane providing at least a portion of a first filtration stage and a second filtration stage, respectively.

30. The filtration system of claim 29, further comprising a filter valve arrangement for switchably fluidly coupling the first filter membrane and / or the second filter membrane to the at least one feed flow.

31. The filtration system according to claim 30, wherein, The controller is further configured to allow the filter valve to switchably couple the first and / or second filter membranes to the at least one feed flow during a first and / or second time period.

32. The filtration system according to claim 1, wherein, The at least one inlet fluid is coupled to the vent of the filtration system such that the at least one feed stream includes concentrate from the filtration system.

33. The filtration system according to claim 1, wherein, The at least one inlet fluid is coupled to the outlet of the filtration system such that the at least one feed stream includes permeate output from the filtration system.

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