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

Abstract

To provide techniques for managing scale formation in water filtration systems, and reverse osmosis (RO) and nanofiltration (NF) systems implementing the techniques.SOLUTION: The present disclosure is directed to filtering techniques that combine elements of continuous and batch NF / RO based on constraints of end-user capabilities to, for example, achieve a target balance of recovery and power consumption and reduce long-term operating costs of the plant. Also disclosed herein is a method of extending a batch operation to a second induction period with injection of an antiscalant, wherein the second induction period allows for higher water recovery.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 991,393, filed March 18, 2020, which is incorporated by reference in its entirety herein.

[0002] This specification relates to filtration systems and managing scale formation within filtration systems. [Background technology]

[0003]

[0003] Water filtration systems often include at least one filter membrane for producing permeate from a feed stream. One approach to water filtration utilizes a steady-state continuous reverse osmosis (RO) process / cycle and a pump that moves the feed through one or more filter membranes at a substantially constant pressure. The ratio of the feed that exits as permeate to the portion of the feed that exits as retentate / reject determines the recovery rate of the system. Such continuous flow systems typically operate at recovery rates below the rate at which a scaling condition is induced. As a result, continuous flow systems have a relatively low maximum recovery rate, e.g., 50-75%, to avoid the formation of scale and fouling.

[0004] Another approach to water filtration utilizes batch RO processes / cycles. In batch RO, a pump varies pressure over time to overcome the osmotic pressure of one or more filter membranes. Batch RO systems allow for relatively high recovery rates relative to continuous flow systems, but such systems must be periodically flushed to maintain permeate flux. Summary of the Invention

[0005]

[0005] The various aspects and features of the present disclosure will be better understood from the following detailed description when read in conjunction with the drawings.

[0006]

[0006] The drawings included in this specification are intended to illustrate various examples of the articles, methods, and devices taught in this specification and are not intended to limit the scope of the teachings in any way. [Brief explanation of the drawings]

[0007] [Figure 1]

[0007] An exemplary diagram of a filtration system continuum is shown with counter electrodes representing continuous and batch RO processes, respectively. [Figure 2A]

[0008] FIG. 1 shows a block diagram of an exemplary filter configuration used in a continuous RO method. [Figure 2B]

[0009] FIG. 1 shows a block diagram of an exemplary filter configuration used in a batch RO process. [Figure 3]

[0010] FIG. 1 illustrates a block diagram of an exemplary filter system according to an embodiment of the present disclosure. [Figure 4]

[0011] 4 illustrates several exemplary filter operation sequences performed by the filter system of FIG. 3 according to an embodiment of the present disclosure. [Figure 5]

[0012] 5 illustrates an example process for performing one or more filter operation sequences of FIG. 4 according to an embodiment of the present disclosure. [Figure 6]

[0013] 4 illustrates an exemplary process for generating first and second induction periods that extend operation of the filter system of FIG. 3 when operating at recovery rates above the unscaling rate, according to one embodiment. [Figure 7]

[0014] 4 is a graph illustrating various collection target rates over time (T) for the filter system of FIG. 3 when performing one or more filter operation sequences, according to an embodiment of the present disclosure. [Figure 8]

[0015] 4 is another graph illustrating various collection target rates over time (T) for the filter system of FIG. 3 when performing one or more filter operation sequences, according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0008]

[0016] The popularity and adoption of RO-based filtration systems continues to grow, especially in large-scale commercial filtration plants. RO-based water filtration systems are classified into one of two modes of operation: continuous RO or batch RO. While both modes of RO filter systems utilize similar filter technologies, such as NF, seawater RO, and brackish water RO technologies, filter systems implementing continuous RO and batch RO processes are at opposite ends of a continuum.

[0009]

[0017] This continuum may be better understood by example. Figure 1 illustrates one such exemplary continuum, with continuous and batch RO processes at opposite ends. Specifically, continuous RO systems operate at relatively low recovery rates to achieve non-scaling steady-state conditions (with or without antiscalants) over operating times measured in weeks to months. Batch RO systems, on the other hand, operate at recovery rates above non-scaling steady-state conditions, i.e., 100% recovery, typically for a fraction of the time continuous RO systems operate before the filter membrane is flushed, e.g., via a feed. For example, some batch RO processes are run for only a few minutes to a few hours before a flush cycle is performed.

[0010]

[0018] Continuous RO systems feature various structural and operational differences from batch RO systems. New and existing filter designs implement batch RO when high recovery rates are desired, and continuous operation when stable, continuous unit operation is desired for weeks or months, when low or no scale inhibitor dosage is preferred, and / or when low water recovery rates are acceptable.

[0011]

[0019] In both cases, the design of water filtration systems using NF and RO technologies typically begins with determining a maximum recovery set point (also referred to herein as water recovery, recovery, or simply recovery) based on identifying the recovery rate at which scaling begins for a selected filter membrane; the identified recovery rate is typically calculated without the use of scale inhibitors, also referred to herein as scale inhibitors. The recovery rate of a filter system is expressed as a ratio defined by the portion of the feed (or feedwater) entering the filter system versus the portion of the feed exiting as permeate. Thus, recoveries less than 100% include at least a portion of the feed output through one or more bleed valves as product retentate, sometimes referred to herein as reject water or simply reject.

[0012]

[0020] Thus, product retentate, also referred to herein as retentate, refers to the portion of the feed that does not pass through the filter membrane, while permeate refers to the portion of the feed that does pass through the filter membrane and is output, for example, as "clean" water, although permeate may not necessarily be potable water depending on the configuration of the filter system and the use of the permeate.

[0013]

[0021] It should be noted that the following disclosure generally refers to the point at which scaling reaches a point of supersaturation of scale-forming compounds, and when fouling reaches a critical flux (or critical concentration) when it substantially reduces or prevents permeate output simply as scaling and fouling, respectively. Some examples and scenarios discussed herein may refer to one or a combination of such scaling and fouling conditions, without necessarily referring to both. For example, various aspects and features disclosed herein refer to a maximum unscaled recovery rate. This value is not limited to scaling alone, but could also refer to the maximum rate before a fouling condition exists.

[0014]

[0022] In the context of a continuous RO / NF system, such as that shown in FIG. 2A, the maximum recovery rate (or set point) is set just below the specific recovery rate at which the onset of a scaling condition occurs. Alternatively, as discussed in more detail below, the maximum recovery set point may operate above the specific recovery rate at which a scaling condition occurs when an inhibitor is utilized. In either case, the continuous RO / NF system then operates at a non-scaling steady state for a period typically measured in weeks or months. During operation, continuous RO / NF systems consume substantially constant power via loads such as pumps that move the feedstream through the filter membrane, and the resulting product retentate is disposed of via sewer or provided to additional filtration stages, further increasing the operating costs of such systems. Continuous RO / NF systems often operate at a constant recovery rate of approximately 50% to 70% to maintain a non-scaling steady state.

[0015]

[0023] Conversely, in the context of a batch RO / NF system, such as that shown in Figure 2B, the maximum recovery (or set point) is set above the specified recovery rate at which the onset of scaling occurs. This configuration can achieve cyclic batch operation in which 100% of the feed is converted to permeate for a period of time, after which the RO system is flushed with feed to discharge the final batch concentrate of the continuous run and then restart the batch cycle.

[0016]

[0024] For example, using batch RO / NF, a maximum recovery rate of 100% may be set, eliminating the need for a bleed to output the product retentate. The RO / NF system, set at such a recovery rate, then operates at a non-steady state, varying the pressure over time to overcome the osmotic pressure of the filter membrane. The total time of such non-steady state operation may be measured in minutes or hours, depending on the specific configuration of the filter system. One advantage of batch RO is that high recovery rates can be achieved without the use of antiscalants.

[0017]

[0025] However, at some point during such batch operation, the osmotic pressure of the filter membrane will exceed the maximum pressure that the system pump can generate. System designers typically limit the time spent operating in such an unsteady state, i.e., beyond the scaling limit, to avoid potential damage and / or dangerous conditions to the filter system. Such limits may include, for example, carefully monitoring system pressure and / or preventing operation in an unsteady state for longer than a certain period of time. Thus, high recovery rates, i.e., 100%, are achieved at the expense of downtime (and reduced recovery rates) to flush the filter membrane and additional wear on the pump caused by high-frequency batch cycling.

[0018]

[0026] Scale inhibitors have improved significantly over the last 20 years, enabling increased recovery rates in both batch and continuous RO systems. Table 1 below shows the ability of various commercially available scale inhibitors to achieve % supersaturation relative to 100% maximum without scale inhibitor, or maximum absolute concentrations of key scaling compounds, or maximum Langelier Saturation Index (LSI) in pH units relative to the saturated pH of calcium carbonate scale in a given NF / RO reject stream. In Table 1, the maximum supersaturation reported from one exemplary public source is shown in the second column, but it should be noted that results may change over time as research into scale inhibitors progresses.

[0019]

[0027] Commercial / large-scale NF / RO systems typically operate at a constant feed rate and a constant recovery rate (resulting in constant permeate and bleed rates), and such systems use antiscalants dosed into the feed to achieve a certain supersaturation. Antiscalant dosages are typically below 5 mg / L to save on chemical costs. However, market demands for higher recovery rates continue to increase, as do reuse demands in the wastewater market. Increasing antiscalant dosages remain the primary means for meeting such demands. At the same time, these same market demands result in higher membrane fouling rates and associated increased chemical costs.

[0020]

[0028] There are also several challenges associated with handling NF / RO bleed streams containing antiscalants. These challenges include the need to post-treat such streams in settling and heat capacity reduction systems and / or the impact of the antiscalant on the receiving stream in the environment. Additional challenges include potential incompatibilities between membranes and antiscalants, and unexpected deleterious interactions between feedstream components and antiscalants, either or both of which can degrade filter system performance.

[0021] [Table 1]

[0022]

[0029] Continuing improvements in water filtration systems utilizing RO technology will depend, at least in part, on advances in filtering technology that allow the features and advantages of continuous and batch RO systems to be integrated to achieve relatively high recovery rates without the existing drawbacks of such recovery rates, such as wear on system components, high power consumption, and the need for the use of antiscalants.

[0023]

[0030] Additionally, a need exists for a filtration system that can generally operate at an intermediate point on the continuum discussed above with respect to FIG. 1 to enable balancing of multiple target parameters, such as total power consumption, wastewater generation, and other costs, that are factors in the system design to achieve a desired water recovery rate that also meets various other requirements and objectives specific to a particular filter system.

[0024]

[0031] In light of the above, the present disclosure is directed to technologies (e.g., systems and methods) that combine elements of continuous and batch NF / RO. Such systems and methods may take into account end-user performance constraints, for example, to achieve a target balance between recovery rate and power consumption and reduce the plant's long-term operating costs. Also disclosed herein is a method for extending batch operation to a second induction period involving scale inhibitor injection, which allows for even higher water recovery rates. The first and / or second induction periods may be extended to move feedwater through a high-pressure filter membrane module, preferably through the use of a high-pressure filter membrane module and pump capable of generating variable pressures, for example, up to 90-120 bar. Beyond scale, the technology disclosed herein may also be used for fouling management, as foulants similarly adversely affect the pressure and recovery rate of NF / RO systems.

[0025]

[0032] The term "substantially" when used in connection with a stated quality, characteristic or value means ±10% of the stated quality, characteristic or value, unless otherwise specified in this disclosure.

[0026]

[0033] As used herein, the term "coupled" refers to any connection, coupling, link, etc., and "fluid coupled" refers to coupling such that fluid from one element can be transferred to another. Such "coupled" elements are not necessarily directly connected to each other, but may be separated by intermediate components / elements. Similarly, the term "directly coupled" refers to a connection between elements without the use of intermediate elements, and "directly fluid coupled" as used herein refers to coupling of elements such that fluid can be transferred from one element to another without the use of intermediate components / elements.

[0027]

[0034] 3 illustrates an example of a filter system 300 consistent with the present disclosure. As shown, the filter system 300 includes a controller 302, at least one pump 304, and a filter stage 306.

[0028]

[0035] The controller 302 comprises at least one processing device / circuit, such as, for example, 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), etc. Preferably, the controller 302 is implemented within a programmable logic controller (PLC). The controller 302 is preferably communicatively coupled to at least one pump 304. The controller 302 may be configured to cause the pump 304 to provide a drive signal to generate a target pressure.

[0029]

[0036] Controller 302 is also preferably communicatively coupled to at least one bleed valve, e.g., bleed valve 308. Controller 302 may be configured to cause bleed valve 308 to provide a control signal. Preferably, the control signal is configured to cause bleed 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 in feed stream 309 to be output as product retentate 310 (also referred to herein as concentrate reject, reject water, or simply reject). As discussed further below, according to certain embodiments, filter valve apparatus 312 may switchably fluidly couple the feed moved by at least one pump 304 to one or more of filter stages 314, sometimes referred to herein as a filter array. Accordingly, controller 302 may be configured to cause filter valve apparatus 312 to provide a control signal that switchably fluidly couples one or more of filter stages 314 to the feed moved via at least one pump 304.

[0030]

[0037] Bleed valve 308 may be implemented as an electromechanical valve configured to be actuated via a control signal received as discussed above. Alternatively, bleed valve 308 may be implemented as any other suitable device, including, for example, a manual valve requiring a technician or engineer to actuate the valve via user-applied force. Filter stage 306 includes at least one filter membrane 311. Preferably, at least one filter membrane 311 is an NF or RO filter membrane.

[0031]

[0038] In one embodiment, the filter stage 306 comprises at least one high-pressure NF or RO filter membrane having a casing / housing capable of handling an operating pressure of at least 1000-1800 psi, preferably at least 1740±5 psi. In one non-limiting example, the at least one filter membrane 311 is implemented as a plate and frame (or spacer tube) high-pressure membrane module configured to withstand an operating pressure of up to 1750 psi. For example, the at least one filter membrane 311 may be implemented as an AquaZoom™ ultra-high-pressure filter module with a pressure casing capable of handling 90-120 bar (1305-1745 psi) from CrossTek Membrane Technology LLC of Holbrook, Massachusetts.

[0032]

[0039] The at least one filter membrane 311 preferably includes at least one inlet 311-1 (or input) fluidly coupled to the feed stream 309 by at least one pump 304. The at least one pump 304 may generate a pressure (preferably a variable pressure) that causes the feed water (also referred to herein as a feed) of the feed stream 309 to be received by and move through the at least one filter membrane 311. Note that while FIG. 3 illustrates an example in which the inlet 311-1 is directly connected to the pump 304, such a configuration is not required. For example, the at least one inlet 311-1 may be fluidly coupled to a bleed of another filter stage / filter system and configured to receive reject output by the bleed as the feed stream 309. Alternatively, the at least one inlet 311-1 may be fluidly coupled to a permeate output of another filter stage / filter system and configured to receive permeate output by the permeate output as the feed stream 309.

[0033]

[0040] The at least one filter membrane 311 further comprises at least one outlet 311-2 for outputting the permeate 313 and at least one bleed 311-3 for outputting the retentate 310. The outlet 311-2 of the at least one filter membrane 311 may be fluidly coupled, for example, to an inlet of another filter stage of the plurality of filter stages 314 for further processing depending on the desired configuration. The at least one bleed 311-3 may also be fluidly coupled to an inlet of another filter stage of the plurality of filter stages 314, or alternatively, to a sewer / wastewater return.

[0034]

[0041] In some embodiments, filter stage 306 is optionally implemented as multiple different filter stages, such as filter stages 314 collectively and individually designated 314-1 through 314-2. Each of the multiple filter stages 314 may further include substantially similar or different types and / or total numbers of filter membranes compared to the other filter stages. For example, first filter stage 314-1 may be configured with one or more filter membranes of a first type, while second filter stage 314-2 may be configured with one or more filter membranes of a second type having a pressure casing capable of withstanding a higher maximum operating pressure than the first type of filter membranes. This difference in filter type may be particularly advantageous when performing high-pressure cycling through second filter stage 314-2. In this scenario, the valve device 312 can switchably fluidly couple the feed from the at least one pump 304 to the second filter stage 314-2 and switchably fluidly disconnect the feed from other filter stages of the plurality of filter stages 314, such as the first filter stage 314-1, which may not necessarily have a pressure casing capable of withstanding the particular pressures of the high-pressure cycle.

[0035]

[0042] The filter valve arrangement 312 may be implemented as an electromechanical valve configured to be actuated via a received control signal as discussed above, or may be implemented via a manual valve that requires a craftsman or technician to actuate the valve via a user-applied force, or any other suitable device including a combination of such a manual valve and an electromechanical valve.

[0036]

[0043] The recovery rate of a filter system can be calculated, in some embodiments, as the amount of permeate produced per amount of feed consumed (or feedwater received). For example, in a batch process, the recovery rate may be calculated according to Equation (1):

[0037]

number

[0038]

[0044] Consider the following scenario: the filter system flushes at 125 gpm for 3 minutes while running at 100 gallons per minute (gpm) for 30 minutes in batch production. In this case, the overall recovery rate of the filter system 300 may be 88.9% = (100 gpm x 30 minutes) / (100 gpm x 30 minutes + 125 gpm x 3 minutes). One advantage of a batch RO process is that the filter system may exceed maximum recovery rate without scaling by operating without antiscalants and for a period of time that is shorter than the time it takes for scaling / fouling conditions to occur, referred to herein as the first induction period.

[0039]

[0045] The designer then defines the characteristics of the feed, e.g., feed 309, preferably any scaling compounds and concentrations in feed 309. The end user's effluent or permeate quality requirements are also preferably defined, such as permeate conductivity, total dissolved solids (TDS, which can be calculated from conductivity), and organic content. Preferably, the effluent or permeate quality requirements are based on conductivity, as conductivity allows for fast online measurement and is a strong indicator of general permeate quality. The designer may also determine the feed flow rate and recovery target desired by the end user. In the example considered herein, the feed flow rate is 100 gpm, the feed has a total dissolved solids (TDS) of 2,000 ppm, and the end user desires a permeate TDS of less than 250 mg / L.

[0040]

[0046] The designer then selects a membrane, preferably determining the scale and TDS rejection characteristics of the selected membrane. For example, a brackish water RO membrane may be selected, and a TDS rejection rate of 99.5% may be used for both TDS and scale rejection.

[0041]

[0047] The designer then determines the water recovery rate at which scaling begins or supersaturation of the scaling compound of interest first occurs. This maximum unscaled recovery rate is determined, for example, by the temperature conditions and other pretreatment dosage conditions (e.g., scale inhibitor dosage, acid dosage) expected to be implemented in the filter system. For example, the maximum unscaled recovery rate may be set at 80% recovery, although the specific set point for the maximum unscaled recovery rate may vary based on the factors discussed above.

[0042]

[0048] The designer then determines a first induction period, e.g., the time from when the maximum non-scaling recovery rate is reached (or exceeded for the first time) until scaling actually occurs, based on, e.g., the temperature conditions and other pretreatment dosage conditions (e.g., scale inhibitor dosage, acid dosage) expected to be implemented in the filter system. For example, the first induction period may be equal to 25 minutes.

[0043]

[0049] The designer may then optionally determine the amount of feed / reject holdup in the filter system. For example, the filter system may be designed to have a feed / reject holdup of 200 gallons.

[0044]

[0050] The designer then preferably sets multiple inputs (or operating parameters) including, for example, dynamic water / carrier fluid properties, scale, foulants, and TDS (total dissolved solids) to generate a mass balance that allows tracking of the carried fluids (e.g., water and components) entering the system, and the bleed and permeate exiting the system, with bleed rates preferably set as inputs by the designer. This mass balance shows the progression of the concentrations of the above parameters in the system over time, and preferably also tracks recovery rates over time.

[0045]

[0051] The designer may then analyze the mass balance and filter system performance outputs based on varying the various inputs / parameters discussed above and select filter system operating parameters that preferably set a recovery rate between 100% and maximum unscaled recovery rates that achieves the desired power consumption rate (and expansion costs) and average recovery rate for the filter system. Preferably, the selected operating parameters also incorporate sewer / reject treatment costs and / or peak power consumption (e.g., peak current when cycling the filter system pumps for flushing, batch cycles, etc.). The designer may also update or modify the selected operating parameters to change the operating setpoints when conditions on the filter system change, such as increased or decreased sewer treatment costs, increased or decreased power costs, and / or increased or decreased recovery targets.

[0046]

[0052] The selected operating parameters may then preferably be output as machine-readable instructions that, when executed by a controller such as controller 302, cause a series of filter operations, such as one or more of the filter sequences shown in Figure 4 and discussed in more detail below. Such instructions may preferably be stored in a memory (not shown) of controller 302.

[0047] Extended induction period for RO / NF filter systems

[0053] This disclosure further recognized that a second induction period may be established by introducing an antiscalant at a predetermined time prior to the end of the first induction period (e.g., when scaling / fouling occurs). This disclosure further determined that the overall recovery achieved by operation of filter system 300 during the first and second induction periods allows for a higher overall recovery rate to be achieved compared to the recovery enabled by filter system 300 through the use of antiscalant dosing alone in a batch / continuous RO cycle. Such first and second induction periods may be factored into a filter system design flow, such as the exemplary filter system design flow discussed above.

[0048]

[0054] As noted above, the feed 309 to the filter stage 306 may be from the reject / retentate stream of another filter stage / system. In such cases, the feed 309 may contain a scale inhibitor. The concentration / amount of the scale inhibitor present in the feed 309, along with the known efficiency of the scale inhibitor, may then be utilized in determining the dosage to produce the second induction period disclosed herein. For example, the scale inhibitor may have a time-dependent efficiency that may require a greater and / or lesser dosage of the scale inhibitor to produce the second induction period, and more importantly, the overall period over which the second induction period extends.

[0049]

[0055] In any event, the specific duration of the second induction period is based at least in part on the performance of the scale inhibitor introduced at a given time and, optionally, any known scale inhibitors present. Thus, the second induction period may be predetermined based at least in part on the performance of the selected scale inhibitor (and / or based on the presence of the scale inhibitor in the feed 309). Preferably, the selected scale inhibitor allows the second induction period to extend for at least half the duration / period of the first induction period, preferably for a period equal to or longer than the duration of the first induction period. Thus, such an extended second induction period may monotonically increase the osmotic pressure up to the rated osmotic pressure limit of the at least one filter membrane 311. Thus, the filter system 300 may be useful when implementing at least one filter membrane 311 as a high-pressure filter membrane module to allow the second induction period to extend for a period including, for example, an associated osmotic pressure of 90-120 bar.

[0050]

[0056] In one embodiment, filter system 300 implements features of both batch RO, with and without antiscalant, with recovery rates set between 100% recovery and unscaled steady state for a portion of the cycle. Preferably, filter system 300 performs at least one filter run at recovery rates set above the maximum unscaled recovery rate but below 100% recovery. This operation is sometimes referred to herein as substantially continuous operation, since the recovery rate may be set above the maximum unscaled recovery rate and have at least a portion of the feedwater output as reject. In contrast, continuous operation involves recovery rates set below the maximum unscaled recovery rate, and batch operation involves recovery rates set at 100% (i.e., no rejects). Thus, filter systems consistent with the present disclosure allow recovery rates higher than those of a similar continuous system and lower than those of a similar batch RO system to achieve a balance of operating parameters such as overall power consumption and sewer costs.

[0051]

[0057] In some embodiments, batch RO and continuous operation / cycling may be performed in a predetermined sequence of filter operations to achieve various end-user requirements regarding, for example, overall recovery rate (e.g., average over a given time period), power consumption, and associated costs such as sewer / disposal costs for disposing of reject water, as discussed above.

[0052]

[0058] It should be noted that the first and second induction periods discussed above are preferably maximized to extend the total time that the batch operation is conducted beyond the non-scaling steady state. However, other batch termination parameters, such as feed concentration factor, feed quality (e.g., total dissolved solids (TDS) conductivity), permeate quality (e.g., permeate conductivity), and / or feed-side pressure, are also parameters that may trigger termination of the filter process or affect the overall duration of the first and / or second induction periods.

[0053]

[0059] It should also be noted that the filter system 300, in combination with the various filtering processes disclosed herein, may utilize one or more energy recovery devices, such as a turbocharger or pressure exchanger, to further increase power efficiency and reduce overall power consumption.

[0054]

[0060] Therefore, in light of the above, one aspect of the present disclosure is to determine optimal recovery rates and power consumption for RO and NF treatment recovery of scaled water by sequencing batch and / or continuous RO operations. Preferably, various features and aspects of the present disclosure can augment / modify existing filter systems, for example, to allow for better control and adjustment of power consumption and overall recovery rates. However, the present disclosure is equally applicable to new filter system designs and is not necessarily limited in this respect.

[0055]

[0061] 4 illustrates several exemplary sequences (A-C), where operation of the filter system 300 of FIG. 3 may include operating according to sequence A, B, C, or any combination thereof, depending, for example, on the desired overall recovery, power consumption, and retentate / reject output. For example, operation may include sequences A and B without sequence C, or sequences A and C without sequence B.

[0056]

[0062] During operation, each selected sequence may include performing each of the steps shown at times I, II, and III, or only some of those steps. For example, sequences A and C may be performed, optionally without necessarily performing the flush step at time III. Similarly, sequences may be performed out of order; for example, sequence A may not necessarily be performed before sequence B, and similarly, sequence C may not necessarily be performed after sequence B, but may instead be performed after sequence A. A sequence may be repeated N times, such that a given sequence repeats a predetermined number of times without other sequences being performed in between. Thus, a particular combination of sequences may include one or more selected sequences performed in a desired order, preferably an order that achieves one or more performance goals, such as overall recovery rate and power consumption. The particular sequences may be stored as machine-readable code (e.g., a configuration file) in a memory (not shown) of the filter system 300 of FIG. 3 .

[0057]

[0063] It should be noted that because sequence C allows the continuous phase to operate as an incomplete flush (also referred to herein as a partial flush) of filter system 300 after the batch phase at time (I), the total number of operating cycles of filter system 300 can be reduced compared to systems that perform a flush after each batch RO cycle. An example of this partial flush is shown below and discussed with reference to FIG. 8. Such a partial flush may advantageously reduce wear on pumps and associated equipment and extend the operating life of the filter system by reducing the period during which the filter system is not outputting permeate (e.g., 0% recovery). This further advantageously not only provides more stable operating conditions for end users, but also provides the filter system with greater power efficiency by reducing energy losses caused by various filter system components, such as current spikes / overcurrents caused by cycling at least one pump 304. Such energy losses can significantly reduce the power efficiency of the filter system as such losses accumulate over the life of the system and ultimately represent a significant power source drain, particularly for high current motors in commercial / large-scale filtration systems.

[0058]

[0064] 5 shows an example process 500 illustrating various aspects and features of the present disclosure. Process 500 particularly includes causing a filter system consistent with the present disclosure to perform a continuous operation / cycle followed by a batch operation / cycle, for example, as shown in example sequence A of FIG. 4. However, process 500 is not necessarily limited in this respect, and other sequences and combinations of sequences are within the scope of the present disclosure.

[0059]

[0065] It should be noted that the actions of process 500 may not necessarily be performed in the order illustrated, and actions may be modified, omitted, and / or added in accordance with 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 combination with one or more components of filter system 300 to achieve automatic operation, e.g., operation of filter system 300 that does not necessarily require manual control and / or intervention by a technician to open / close at least one bleed valve 308 and generate a target pressure for at least one pump 304.

[0060]

[0066] Alternatively, process 500 may be performed by manual operation, e.g., by a user manually activating a switch to send a control signal to actuate at least one bleed valve 308 and / or filter valve device 312, or by a combination of automated and manual steps. For example, controller 302 may be configured to cause at least one pump to generate a target pressure via an automated sequence, while bleed valve 308 may be manually actuated by a technician to achieve a desired recovery rate. Among other things, controller 302 may be configured to provide a visual indicator, e.g., via a computer system user interface, LED lights, etc., based on a timer / schedule that causes a technician to perform one or more manual steps / procedures, such as actuating at least one bleed valve 308.

[0061]

[0067] Process 500 begins with act 502. In act 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 greater than the maximum unscaled recovery rate of the filter system, e.g., at least 80% recovery, but less than 100%. Additional non-limiting examples of first target recovery rates include those greater than the maximum unscaled recovery rate of at least one filter membrane but less than or equal to 98%. In such cases, the remainder of the feedwater may be output as reject. For example, associated with a first target recovery rate greater than the maximum unscaled recovery rate but less than or equal to 98%, at least 2% of the feedwater may be output as reject during the first time period. However, the first target recovery rate may also be selected to be less than or equal to the maximum unscaled recovery rate of the filter system in scenarios where steady-state continuous operation of at least one cycle is desired.

[0062]

[0068] In act 504, the controller 302 causes the at least one bleed 308 to output a predetermined portion of the feedstream, e.g., feedstream 309, as retentate / rejects for a first time period based on a first target recovery rate. For example, in one embodiment, 80% recovery is set as the first target recovery rate, so the at least one bleed 308 may be configured to output 20% of the feedstream as retentate.

[0063]

[0069] In act 506, the controller 302 provides a drive signal (or a first drive signal) to at least one pump, e.g., pump 304, causing the pump to generate an output permeate stream for a first time period based on the determined first target recovery rate. In some embodiments, the first drive signal is configured to cause the at least one pump to generate a substantially constant pressure such that the pressure increases by a maximum of 10 psi per hour from an initial pressure that achieves the target recovery rate over the first time period. In some embodiments, the first time period is 1-2 hours, preferably at least 6 hours. Note that the rate of pressure change in substantially continuous operation varies depending on several factors, including, for example, feedwater characteristics and / or recovery setpoint. For example, a 99% recovery rate in substantially continuous operation will result in a relatively higher pressure increase per minute compared to operation at a 90% recovery rate. Therefore, the exemplary pressure values ​​and change rates provided herein in connection with substantially continuous operation are not intended to be limiting.

[0064]

[0070] In act 508, the controller 302 determines a second target recovery rate. In some embodiments, the second target recovery rate is higher than the first target recovery rate. Some non-limiting examples of the second target recovery rate include recovery rates of 70-80%, 80-100%, 90-100%, and all values ​​and ranges therebetween. In some embodiments, the second target recovery rate is 95-100%, preferably 100%. In other embodiments, the second target recovery rate is lower than the first target recovery rate, resulting in at least a partial flush of at least one filter membrane. For example, the second target recovery rate may be set at or below the maximum unscaled recovery rate of at least one filter membrane 311, e.g., 0-80%, preferably greater than 0%, to allow permeate production to continue during the partial flush.

[0065]

[0071] Alternatively or additionally, the second target recovery rate is less than or equal to the maximum unscaled recovery rate of the at least one filter membrane for a portion of the second time period and greater than the maximum unscaled recovery rate for a portion of the second time period.

[0066]

[0072] In act 510, the controller 302 causes the at least one bleed 308 to output a predetermined portion of the feedstream, e.g., feedstream 309, as rejects during a second time period based on a second target recovery rate. In one exemplary scenario, the second recovery rate is 100%, so that the predetermined portion of the feedstream 309 output as rejects is zero (0%) or substantially zero (0%), such that no more than 2% of the feedstream 309 is output as rejects. Thus, in this embodiment, the controller 302 causes the at least one bleed 308 to close and cause substantially no portion of the feedstream 309 to be output as rejects during the second time period.

[0067]

[0073] Alternatively, the second target recovery is less than 100%, so that the predetermined portion of the feed stream 309 is proportional to the particular target recovery. For example, the second target recovery may be set between 96 and 100%, such that the volumetric ratio of the received feed water to the output permeate stream is between 0.96 and 1.0 during the second time period. In another example, the second target recovery may be set between 0 and 80%, as discussed above, to effect at least a partial flush.

[0068]

[0074] In act 512, the controller 302 causes the at least one pump to provide a drive signal (or a second drive signal) to generate an output permeate stream for a second time period based on the determined second target recovery rate. For example, the drive signal may be configured to cause the at least one pump to monotonically increase pressure for the second time period to exceed the osmotic pressure of the at least one filter membrane, e.g., the at least one filter membrane 311 of FIG. 3 . Alternatively, the drive signal may be configured to cause a flush or partial flush, as discussed above. Also, the second drive signal may be configured substantially similar to the first drive signal discussed above, and its description and features will not be repeated for the sake of brevity.

[0069]

[0075] Preferably, the second drive signal is configured to cause the at least one pump to generate a substantially constant pressure such that the pressure increases by at least 10 psi per minute, preferably at least 50 psi per minute, over a second period of time, hi one embodiment, the second period of time is at least 2 minutes.

[0070]

[0076] As discussed in more detail below, act 512 may further include the controller 302 introducing a second induction period and introducing a scale inhibitor dose at a predetermined time to extend the overall duration of the second period, thereby increasing the overall recovery rate (e.g., time-averaged).

[0071]

[0077] FIG. 6 depicts an exemplary process 600 illustrating various aspects and features of the present disclosure. Process 600 specifically involves extending batch RO cycling (e.g., with an associated recovery rate greater than the maximum unscaled recovery rate and less than 100%, or preferably set equal to 100% recovery) by introducing a second induction period in a filter system consistent with the present disclosure. It should be noted that process 600 may be performed by any filter system capable of batch RO treatment, including, but not limited to, filter system 300 of FIG. 3 and / or a filter system equipped with a high-pressure filter membrane module as described above. However, a filter system implementing process 600 preferably includes a high-pressure filter membrane module that allows the second induction period to extend to the moment the osmotic pressure of the associated filter membrane reaches 90-120 bar or greater.

[0072]

[0078] Process 600 may be performed, for example, in providing a drive signal in acts 506 and / or 512 of process 500 of Figure 5 discussed above, although process 600 is not necessarily limited in this respect, and process 600 may be performed by a filter system without necessarily performing the acts of process 500. Additionally, the acts of process 600 may not necessarily be performed in the order shown, and acts may be modified, omitted, and / or added in accordance with various aspects and features disclosed herein without departing from the scope of the disclosure.

[0073]

[0079] In act 602, the controller 302 sets a recovery rate higher than the maximum unscaling rate of at least one filter membrane, such as at least one filter membrane 311. In certain embodiments, the recovery rate is between 90 and 99.99%, more preferably 100%.

[0074]

[0080] In act 604, the controller 302 causes the at least one pump to monotonically increase a pressure above the osmotic pressure of the at least one filter membrane for a first time period. In act 606, the controller 302 determines a first predetermined point in time between the occurrence of a scaling condition in the first time period and the time when scaling of the at least one filter membrane occurs. In some embodiments, the predetermined point in time is the initial start of the first time period or a point after the initial start of the first time period prior to scaling and / or fouling of the at least one filter membrane.

[0075]

[0081] In 608, the controller 302 causes one or more doses of antiscalant to be introduced to the at least one filter membrane at predetermined times. In act 610, the controller 302 causes the at least one pump to continue monotonically increasing the pressure above the osmotic pressure of the at least one membrane until a second predetermined time. The second predetermined time may be based, for example, on a fixed time period and / or other conditions and factors to maintain stability of the filter system.

[0076]

[0082] FIG. 7 shows an exemplary graph 700 illustrating the operation of filter system 300 when performing processes 500 and 600 of FIGS. 5 and 6, respectively. Graph 700 includes a target recovery range of 0% to 100% on the Y-axis and time on the X-axis. In this exemplary sequence, filter system 300 operates at a first target recovery rate, e.g., 80%, for a first time period (T0 to T0+1) according to acts 502-506 of process 500 of FIG. 5. As shown, this first target recovery rate may be selected as a rate that is preferably greater than a predetermined maximum unscaling / fouling recovery rate of at least one filter membrane 311 of filter system 300.

[0077]

[0083] After the end of the first period (e.g., T0+1), the filter system 300 operates at a second target recovery rate, e.g., 98%, during a second period (e.g., T0+1 to T0+2 or T0+1 to T0+3). The second period defines at least a first induction period, which is the time between when the recovery rate of the filter system 300 exceeds the non-scaling / fouling recovery rate (e.g., the recovery rate at which the onset of a scaling / fouling condition occurs) and when scaling / fouling occurs. That is, during the second period, the target recovery rate exceeds the maximum non-scaling recovery rate of the filter system 300, and there is an associated period before one or more filter membranes reach a maximum non-scaling recovery state without intentionally injecting an inhibitor (sometimes referred to as a maximum non-scaling recovery state before inhibitor injection). As shown, the filter system 300 reaches the maximum non-scaling recovery state before inhibitor injection shortly after T0+2 during the first induction period. It should be noted that, as discussed above, scale inhibitors may be present in the feed, and the term "pre-injection of scale inhibitors" does not exclude the presence of such pre-existing scale inhibitors.

[0078]

[0084] As further shown, the filter system 300, and more specifically the controller 302, may determine a predetermined point in time, shown as TO+2, just prior to reaching a maximum pre-antiscalant injection non-scaling recovery condition, e.g., when scaling / fouling occurs during the first induction period based, for example, on act 606 of process 600 of FIG. 6 .

[0079]

[0085] At a predetermined point in time, controller 302 may cause an antiscalant dose to be introduced / injected into at least one filter membrane 311, for example, based on act 608 of process 600 of Figure 6 discussed above, and operation of filter system 300 at the second target recovery rate may continue during a second induction period, for example, until the osmotic pressure of at least one filter membrane 311 exceeds the maximum pressure of at least one pump 304, or until a predetermined maximum time of operation of filter system 300 during the second induction period has elapsed to avoid operating filter system 300 in an unstable state.

[0080]

[0086] Thus, for example, introducing an inhibitor at a predetermined time point extends the maximum non-scaling recovery state of the filter system 300 to T0+3, and this shifted / extended recovery state is also referred to as a maximum non-scaling recovery state after inhibitor injection. During this extended period, the osmotic pressure of the at least one filter membrane may exceed the maximum pressure that can be generated by the at least one pump 304 and / or the maximum pressure rating of the filter membrane, for example, before the end of the second induction period (e.g., T0+3). Thus, the filter system 300 may be configured to continue batch operation at the second target recovery rate for a predetermined maximum time during the second induction period, which predetermined maximum time is less than the overall duration of the second induction period provided by the introduction of the inhibitor dosage at the predetermined time point. The predetermined maximum time may be selected as a fixed duration, e.g., 1 minute, 3 minutes, 1-30 minutes, or may be dynamically set based, for example, on the dosage of the scale inhibitor, and / or known scale inhibitor performance grades, and / or known feed conditions, pressure or other equipment constraints, and / or permeate or reject quality requirements, which may be measured online, e.g., via an Internet of Things (IoT) device.

[0081]

[0087] Thus, in such cases, the predetermined time point distinguishes the first induction period from the second induction period, as shown in Figure 7. Note that the first and second induction periods may be substantially equal in duration or may be different, with the second induction period preferably being at least half the duration of the first induction period.

[0082]

[0088] 8 shows an exemplary graph 800 illustrating the operation of filter system 300 when performing process 500 of FIG. 5, according to one embodiment. Graph 800 includes target recovery rates of 0% to 100% on the Y-axis and time on the X-axis. In this exemplary scenario, filter system 300 operates in a sequence including substantially continuous operation at a first recovery target (greater than maximum unscaled recovery rate but less than 100% recovery rate) and batch operation at a second recovery target (100% recovery rate). The sequence further includes an optional flush cycle, discussed below.

[0083]

[0089] As shown in the figure, the overall duration of each substantially continuous operation is D1, and the overall duration of each batch operation is D2. D1 can be at least 6 hours, and preferably D1 is at least 1 day, while D2 can be at least 1 minute to several hours, and preferably at least 5 minutes. Thus, D1 can be significantly longer in duration than D2.

[0084]

[0090] The duration D1 of each substantially continuous operation may be uniform or may vary such that each operation is longer, shorter, or substantially equal to other substantially continuous operations. Similarly, the duration D2 of each batch operation may be uniform or may vary such that each operation is longer, shorter, or substantially equal to other batch operations. As discussed above, a scale inhibitor may be introduced at a predetermined time to introduce / trigger a second induction period. Thus, one or more batch operations may include a longer duration D2 than other batch operations that do not include the use of a scale inhibitor to obtain a second induction period.

[0085]

[0091] As further shown, the filter system 300 may be operated at 0% recovery to cause an optional (complete) flush of at least one filter membrane 311 such that all of the received feedwater is output as reject. The optional flush may be caused, for example, by the second drive signal discussed above for process 500 of FIG. 5. Alternatively, the optional flush may be caused by a third drive signal. Preferably, the third drive signal is configured to cause a third target recovery, e.g., 0% for a complete flush, or greater than zero (0%) and up to a maximum unscaled recovery (e.g., 80%) for a partial flush. In some embodiments, the third target recovery may be different from both the first and second target recoveries discussed above for process 500 of FIG. 5.

[0086]

[0092] For example, as shown, filter system 300 may operate at a maximum non-scaling / fouling recovery rate, e.g., 1-80%, preferably less than 80%, based on a third drive signal during a third time period (or duration) D3. Duration D3 is designed to cause at least a partial flush of at least one filter membrane 311 without requiring a full flush (e.g., 0% recovery for a period of time). Thus, filter system 300 may continue to produce a permeate stream without an intervening full flush, i.e., without necessarily dropping to 0% recovery to flush, e.g., after batch RO operation.

[0087]

[0093] Thus, aspects of this disclosure enable NF / RO designers to select an optimal operating approach that combines continuous and batch NF / RO options based on end-user performance constraints and reduces the long-term operating costs of the plant. Also disclosed herein is a method for extending batch operation to a second induction period that allows for even higher water recovery rates through antiscalant injection. Beyond scale, the techniques and features disclosed herein may also be used for fouling management, as foulants similarly adversely affect pressure and recovery in NF / RO systems.

[0088] Additional Exemplary Aspects and Architectures

[0094] One aspect of the present disclosure includes methods for determining recovery and power requirements / parameters (also referred to herein as operating parameters) that allow an NF / RO system to operate at set points that lie on a continuum between two extremes: non-scaling steady-state operation (with or without antiscalant) typically provided by continuous systems, and 100% recovery batch operation provided by RO systems. Accordingly, the following disclosure provides the following non-limiting examples:

[0089]

[0095] Example 1 involves operating an NF / RO system with at least one feed stream, one bleed stream, and one permeate stream at a recovery rate set between 100% recovery and maximum non-scaling or non-fouling recovery for at least a portion of the operating cycle.

[0090]

[0096] Example 2 involves operating an NF / RO system with at least one feed stream, one bleed stream, and one permeate stream at a recovery rate set between 100% recovery and maximum non-scaling or non-fouling recovery for at least a portion of an operating cycle, including a feed flush sequence as the final step of the operating cycle before repeating the operating cycle (see, e.g., Sequence B in Figure 4).

[0091]

[0097] Example 3 involves a method of operating an NF / RO system with at least one feed stream, one bleed stream, and one permeate stream at a recovery rate set between 100% recovery and maximum non-scaling or non-fouling recovery for part of the operating cycle, and at 100% recovery for another part of the operating cycle (e.g., without necessarily requiring a flush cycle; see sequences A and C in Figure 4).

[0092]

[0098] Example 4 is a method of operating an NF / RO system with at least one feed stream, one bleed stream, and one permeate stream at a recovery rate set between 100% recovery and maximum non-scaling or non-fouling recovery for part of the operating cycle, and at 100% recovery for another part of the operating cycle, including a feed flush sequence as the final step of the operating cycle before repeating the operating cycle (see, e.g., sequences A and C in Figure 4).

[0093]

[0099] Example 5 is a method of operating an NF / RO system with at least one feed stream, one bleed stream, and one permeate stream at a recovery rate set between 100% recovery and maximum non-scaling or non-fouling recovery for at least a portion of an operating cycle by first operating without an inhibitor in a first induction period until a predetermined point just before scaling / fouling occurs, and then adding an inhibitor to the feed to allow for extended operation (e.g., a second induction period) just before the final step of the operating cycle, culminating in a feed flush sequence, before repeating the operating cycle one or more times.

[0094]

[0100] Example 6 is a method of operating an NF / RO system having at least one feed stream, one bleed stream, and one permeate stream at a recovery rate set between 100% recovery and maximum non-scaling or non-fouling recovery for part of an operating cycle, and at 100% recovery for another part of the operating cycle, by first operating without scale inhibitor in a first induction period until just before reaching an induction period without scale inhibitor use (i.e., a second induction period), and then adding a dose of scale inhibitor to the feed to allow for extended operation (e.g., a second induction period) until just before reaching an inhibitor induction period culminating in a feed flush sequence that is the final step of the operating cycle, before repeating the operating cycle.

[0095]

[0101] Example 7 is a method of operating an NF / RO system with at least one feed stream and one permeate stream at 100% recovery by first operating without scale inhibitors during a first induction period until just before reaching an induction period without scale inhibitors (second induction period), and then adding scale inhibitor dosing to the feed to allow for extended operation (second induction period) culminating in a feed flush sequence as the final step of the operating cycle before repeating the operating cycle.

[0096]

[0102] Example 8 is a method of operating an NF / RO system with at least one feed stream and one permeate stream at 100% recovery using a scale inhibitor to allow concentration beyond the scale inhibitor-free induction period until just prior to the scale inhibitor induction period, before repeating the operating cycle and concluding with a feed flush sequence as the final step of the operating cycle.

[0097]

[0103] Example 9 is a method for operating an NF / RO system with plate and frame or spacer tube high pressure membrane modules and at least one feed stream and one permeate stream at 100% recovery by first operating without an inhibitor until just before an induction period without the use of an inhibitor, and then adding an inhibitor to the feed to allow for extended operation (a second induction period) until just before an inhibitor induction period culminating in a feed flush sequence as the final step of the operating cycle, before repeating the operating cycle.

[0098]

[0104] Example 10 is a method of operating an NF / RO system with plate and frame or spacer tube high pressure membrane modules and at least one feed stream and one permeate stream at 100% recovery, using a scale inhibitor to allow concentration beyond the scale inhibitor induction period until just before the scale inhibitor induction period, before repeating the operating cycle and concluding with a feed flush sequence as the final step of the operating cycle.

[0099]

[0105] Example 11 is a method of operating a filtration system having at least one inlet fluidly coupled to at least one feedstream, at least one filter membrane fluidly coupled to the at least one inlet to receive feedwater from the at least one feedstream, and at least one pump for generating a pressure to move the feedwater from the at least one feedstream through the at least one filter membrane and produce an output permeate stream, the method comprising providing a first drive signal to the at least one pump to cause the generated pressure to produce the output permeate stream in a first time period at a recovery substantially equal to a first target recovery that is greater than the maximum unscaled recovery of the at least one filter membrane and less than 100%.

[0100]

[0106] Example 12 includes the features of example 11, further including causing the generated pressure to provide a second drive signal to the at least one pump to produce an output permeate stream for a second time period at a recovery rate substantially equal to a second target recovery rate.

[0101]

[0107] Example 13 includes the features of example 12, wherein the second target recovery rate is less than or equal to the maximum unscaled recovery rate of the at least one filter membrane.

[0102]

[0108] Example 14 includes the features of example 12, wherein the second target recovery rate is greater than the maximum unscaled recovery rate of the at least one filter membrane.

[0103]

[0109] Example 15 includes the features of example 12, wherein the second target recovery is greater than the maximum unscaled recovery of the at least one filter membrane and the first target recovery.

[0104]

[0110] Example 16 includes the features of example 12, wherein the second drive signal is configured to cause at least a partial flush of the at least one filter membrane such that the second target recovery rate is less than a maximum unscaled recovery rate of the at least one filter membrane.

[0105]

[0111] Example 17 includes the features of example 16, wherein the second target recovery is equal to zero such that all of the received feedwater for at least one feedstream is output as reject.

[0106]

[0112] Example 18 includes the features of example 12, wherein the second target recovery rate is less than or equal to the maximum unscaled recovery rate of the at least one filter membrane for a portion of the second time period and greater than the maximum unscaled recovery rate for a portion of the second time period.

[0107]

[0113] Example 19 includes the features of example 12, wherein the second target recovery is greater than 0% and less than or equal to the maximum unscaled recovery to cause a partial flush of at least one filter membrane.

[0108]

[0114] Example 20 includes the features of example 12, wherein a second target recovery is 96 to 100% such that the volume ratio of the received feed water to the output permeate stream is 0.96 to 1.0 during a second time period.

[0109]

[0115] Example 21 includes the features of example 12, further including causing at least one bleed valve 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 reject water during a second time period.

[0110]

[0116] Example 22 includes the features of example 21, wherein the second target recovery is equal to 100%, and wherein causing the at least one bleed valve to output a first predetermined portion of the at least one feedstream as reject water during the second time period further includes closing the at least one bleed valve such that substantially 0% of the at least one feedstream is output as reject water.

[0111]

[0117] Example 23 includes the features of example 21, wherein the second target recovery is less than 100%, and causing the at least one bleed valve to output a first predetermined portion of the at least one feed stream as reject water for a second time period further includes opening the at least one bleed valve to output the first predetermined portion of the feed stream as reject water.

[0112]

[0118] Example 24 includes the features of example 12, wherein the second target recovery is 100% such that 0% of the at least one feedstream is output as reject water during at least a portion of the second time period.

[0113]

[0119] Example 25 includes the features of example 12, wherein the second period occurs before or after the first period based on a predetermined sequence of filter operations.

[0114]

[0120] Example 26 includes the features of example 12, wherein the second target recovery rate is 100%, and wherein providing the second drive signal to the at least one pump further includes introducing one or more doses of antiscalant to the at least one filter membrane at predetermined times during the second period, the predetermined times dividing the second period into a first induction period occurring before the predetermined time and a second induction period during which the antiscalant is introduced occurring after the predetermined time, the first induction period being a period acting before scaling and / or fouling of the at least one filter membrane occurs, and the second induction period being a period measured from when the antiscalant is introduced to when scaling and / or fouling of the at least one filter membrane occurs.

[0115]

[0121] Example 27 includes the features of any one of Examples 11 to 26, further including causing the at least one pump to provide a third drive signal to at least partially flush the at least one filter membrane, and wherein causing the at least one pump to provide the third drive signal to at least partially flush the at least one filter membrane further includes causing the at least one pump to provide the third drive signal during a third time period after the second time period.

[0116]

[0122] Example 28 includes the features of example 27, wherein the third drive signal is configured to generate a pressure in the at least one pump to produce the output permeate stream at a recovery rate substantially equal to a third target recovery rate for a third time period.

[0117]

[0123] Example 29 includes the features of example 28, wherein the third target recovery is between 0% and 80% in the third time period to cause at least partial flushing of the at least one filter membrane.

[0118]

[0124] Example 30 includes the features of example 28, wherein the third target recovery rate is substantially 0% to cause a complete flush of the at least one filter membrane, and the third target recovery rate is different from the first target recovery rate and the second target recovery rate.

[0119]

[0125] Example 31 includes the features of any one of Examples 11 to 30, wherein the second time period follows the first time period, and providing the second drive signal during the second time period occurs without an intervening full flush of the at least one filter membrane between the first and second time periods.

[0120]

[0126] Example 32 includes the features of example 12, wherein the second drive signal is configured to increase the pressure generated by the at least one pump above the osmotic pressure of the at least one filter membrane such that the pressure increases by at least 10 psi per minute over a second period of time, wherein the second period of time is at least 2 minutes.

[0121]

[0127] Example 33 includes the features of example 12, wherein the second drive signal is configured to generate a substantially constant pressure in the at least one pump, such that the substantially constant pressure increases by up to 10 pounds per square inch (psi) per hour over a second period of time, the second period of time being at least 6 hours.

[0122]

[0128] Example 34 includes the features of any one of Examples 11 to 33, wherein the first drive signal is configured to increase the pressure generated by the at least one pump above the osmotic pressure of the at least one filter membrane such that the pressure increases by at least 10 psi per minute over a first period of time, wherein the first period of time is at least 2 minutes.

[0123]

[0129] Example 35 includes the features of any one of Examples 11 to 33, wherein the first drive signal is configured to generate a substantially constant pressure in the at least one pump, such that the substantially constant pressure increases by up to 10 pounds per square inch (psi) per hour over a first period of time, wherein the first period of time is at least 6 hours.

[0124]

[0130] Example 36 includes the features of any one of Examples 11 to 35, further including causing at least one bleed valve 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 reject water during the first time period.

[0125]

[0131] Example 37 includes the features of example 36, wherein the first target recovery is less than or equal to 98%, and wherein causing the at least one bleed valve to output a second predetermined portion of the feedwater for the at least one feedstream as reject water during the first time period further includes opening the at least one bleed valve to output at least 2% of the feedwater for the at least one feedstream as reject water during the first time period.

[0126]

[0132] Example 38 includes the features of any one of Examples 11 to 37, and further includes causing the providing of the first drive signal to the at least one pump to introduce one or more doses of scale inhibitor to the at least one filter membrane at a predetermined time during the first time period, the predetermined time at an initial start of the first time period or a time after the initial start of the first time period and prior to scaling and / or fouling of the at least one filter membrane.

[0127]

[0133] Example 39 includes the features of example 38, wherein the predetermined time point divides the first period into a first induction period occurring before the predetermined time point and a second induction period occurring after the predetermined time point during which a scale inhibitor is introduced, the first induction period being a period of time that acts before scaling and / or fouling of the at least one filter membrane occurs, and the second induction period being a period measured from when the scale inhibitor is introduced to when scaling and / or fouling of the at least one filter membrane occurs.

[0128]

[0134] Example 40 includes the features of example 39, wherein providing the first drive signal to the at least one pump further 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 point at which the antiscalant is introduced to maintain the first target recovery rate during at least a portion of the second induction period.

[0129]

[0135] Example 41 is a filter system comprising: at least one inlet fluidly coupled to at least one feedstream; at least one filter membrane fluidly coupled to the at least one inlet for receiving feedwater from the at least one feedstream; at least one pump for generating a pressure to move the feedwater from the at least one feedstream through the at least one filter membrane and produce an output permeate stream; and a controller configured to cause the generated pressure to provide a first drive signal to the at least one pump to produce the output permeate stream for a first time period at a recovery rate substantially equal to a first target recovery rate that is greater than a maximum unscaled recovery rate of the at least one filter membrane and less than 100%.

[0130]

[0136] Example 42 includes the features of example 41, and further configures the controller to provide a second drive signal to the at least one pump to cause the generated pressure to produce an output permeate stream at a recovery rate substantially equal to a second target recovery rate for a second time period.

[0131]

[0137] Example 43 includes the features of example 42, wherein the second target recovery rate is less than or equal to the maximum unscaled recovery rate of the at least one filter.

[0132]

[0138] Example 44 includes the features of example 42, wherein the second target recovery rate is greater than the maximum unscaled recovery rate of the at least one filter membrane.

[0133]

[0139] Example 45 includes the features of example 42, wherein the second target recovery is greater than the maximum unscaled recovery of the at least one filter membrane and the first target recovery.

[0134]

[0140] Example 46 includes the features of example 42, wherein the second drive signal is configured to cause at least partial flashing of the at least one filter membrane.

[0135]

[0141] Example 47 includes the features of example 46, wherein the second target recovery is equal to zero such that all of the feedwater for at least one feedstream is output as reject.

[0136]

[0142] Example 48 includes the features of example 46, wherein the second target recovery is less than or equal to the maximum unscaled recovery of the at least one filter membrane for a portion of the second time period and greater than the maximum unscaled recovery for a portion of the second time period.

[0137]

[0143] Example 49 includes the features of example 46, wherein the second target recovery is greater than 0% and less than the maximum unscaled recovery to cause partial flushing of at least one filter membrane.

[0138]

[0144] Example 50 includes the features of Example 42, wherein a second target recovery is 96 to 100% such that the volumetric ratio of the received feed water to the output permeate stream is 0.96 to 1.0 during a second time period.

[0139]

[0145] Example 51 includes the features of example 42, further comprising at least one bleed valve 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 reject water during a second time period.

[0140]

[0146] Example 52 includes the features of example 51, wherein the second target recovery percentage is equal to 100%, and the controller is configured to close the at least one bleed valve so that the first predetermined portion of the feed water output as reject water is zero percent during the second time period.

[0141]

[0147] Example 53 includes the features of example 51, wherein the second target recovery is 100% such that 0% of the at least one feed stream is output as reject water during the second time period.

[0142]

[0148] Example 54 includes the features of example 51, wherein the second period occurs before or after the first period based on a predetermined sequence of filter operations stored in memory.

[0143]

[0149] Example 55 includes the features of any one of Examples 42 to 54, further configured to cause the second drive signal to introduce one or more doses of scale inhibitor to the at least one filter membrane at predetermined times during the second time period.

[0144]

[0150] Example 56 includes the features of example 55, wherein the predetermined time point divides the second period into a first induction period occurring before the predetermined time point and a second induction period occurring after the predetermined time point during which a scale inhibitor is introduced, the first induction period being a period of time that acts before scaling and / or fouling of the at least one filter membrane occurs, and the second induction period being a period measured from when the scale inhibitor is introduced to when scaling and / or fouling of the at least one filter membrane occurs.

[0145]

[0151] Example 57 includes the features of any one of Examples 42 to 56, and further configures the controller to provide a third drive signal to the at least one pump to cause the at least partial flush to occur in a third time period after the second time period.

[0146]

[0152] Example 58 includes the features of example 57, wherein the third drive signal is configured to generate a pressure that causes the at least one pump to produce the output permeate stream at a recovery rate substantially equal to a third target recovery rate, the third target recovery rate being different from the first and second target recoveries, during a third time period.

[0147]

[0153] Example 59 includes the features of examples 57 or 58, wherein the third target recovery is between 0% and 80% in the third time period to cause at least partial flushing of the at least one filter membrane.

[0148]

[0154] Example 60 includes the features of Examples 57 or 58, wherein the third recovery rate is substantially 0% to cause complete flushing of the at least one filter membrane.

[0149]

[0155] Example 61 includes the features of any one of Examples 42 to 60, wherein the second time period follows the first time period, and providing the second drive signal during the second time period occurs without intervening full flushing of the at least one filter membrane between the first and second time periods.

[0150]

[0156] Example 62 includes the features of example 42, wherein the second drive signal is configured to increase the pressure generated by the at least one pump above the osmotic pressure of the at least one filter membrane such that the pressure increases by at least 10 psi per minute over a second period of time, wherein the second period of time is at least 2 minutes.

[0151]

[0157] Example 63 includes the features of example 42, wherein the second drive signal is configured to generate a substantially constant pressure in the at least one pump such that the substantially constant pressure increases by up to 10 pounds per square inch (psi) per hour over a second period of time, the second period of time being at least 6 hours.

[0152]

[0158] Example 64 includes the features of any one of Examples 41 to 63, wherein the first drive signal is configured to increase the pressure generated by the at least one pump to a pressure above the osmotic pressure of the at least one filter membrane such that the pressure increases by at least 10 psi per minute over a first period of time, wherein the first period of time is at least 2 minutes.

[0153]

[0159] Example 65 includes the features of any one of Examples 41 to 63, wherein the first drive signal is configured to generate a substantially constant pressure in the at least one pump, such that the substantially constant pressure increases by up to 10 pounds per square inch (psi) per hour over a first period of time, wherein the first period of time is at least 6 hours.

[0154]

[0160] Example 66 includes the features of any one of Examples 41 to 65, further comprising at least one bleed valve 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 reject water during a first time period.

[0155]

[0161] Example 67 includes the features of example 66, wherein the first target recovery is less than or equal to 98% and the first predetermined portion of the feedwater is at least 2%, and the controller is configured to cause the at least one bleed valve to output the first predetermined portion of the feedwater of the at least one feedstream that is output during the first time period as reject water.

[0156]

[0162] Example 68 includes the features of any one of Examples 41 to 67, wherein the controller is further configured to cause one or more doses of scale inhibitor to be introduced to the at least one filter membrane at predetermined times during the first time period.

[0157]

[0163] Example 69 includes the features of example 68, wherein the predetermined time point divides the first period into a first induction period occurring before the predetermined time point and a second induction period occurring after the predetermined time point during which a scale inhibitor is introduced, the first induction period being a period of time that acts before scaling and / or fouling of the at least one filter membrane occurs, and the second induction period being a period measured from when the scale inhibitor is introduced to when scaling and / or fouling of the at least one filter membrane occurs.

[0158]

[0164] Example 70 includes the features of example 69, wherein providing the first drive signal to the at least one pump further 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 point at which the antiscalant is introduced to maintain the first target recovery rate during at least a portion of the second induction period.

[0159]

[0165] Example 71 includes the features of any one of Examples 41 to 70, wherein the at least one filter membrane includes at least one high-pressure filter membrane with a pressure casing capable of withstanding a pressure of at least 90 bar.

[0160]

[0166] Example 72 includes the features of any one of Examples 41 to 71, wherein the at least one filter membrane includes at least first and second filter membranes, each providing at least a portion of a first and second filter stage, respectively.

[0161]

[0167] Example 73 includes the features of example 72, further comprising a filter valve device for switchably fluidly coupling the first and / or second filter membranes to the at least one feed stream.

[0162]

[0168] Example 74 includes the features of Example 73, wherein the controller is further configured to cause the filter valve apparatus to switchably fluidly couple the first and / or second filter membranes to the at least one feed stream during first and / or second time periods.

[0163]

[0169] Example 75 includes the features of any one of Examples 41 to 74, wherein the at least one inlet is fluidly coupled to a bleed of the filter system such that the at least one feed stream includes a concentrate from the filter system.

[0164]

[0170] Example 76 includes the features of any one of Examples 41 to 74, wherein the at least one inlet is fluidly coupled to an outlet of the filter system such that the at least one feed stream comprises permeate output by the filter system.

[0165]

[0171] Example 77 is a method of operating a filtration system having an inlet fluidly coupled to at least one feedstream, at least one filter membrane fluidly coupled to the inlet to receive feedwater of the at least one feedstream, and at least one pump for generating a pressure to move the feedwater of the at least one feedstream through the at least one filter membrane and generate an output permeate stream, the method including: increasing the pressure generated by the at least one pump to a pressure above an osmotic pressure of the at least one filter membrane and providing a first drive signal to the at least one pump to maintain a target recovery rate for a first time period that exceeds a maximum unscaled recovery rate and has an associated time period before reaching a maximum unscaled recovery state for the at least one filter membrane; detecting that the maximum unscaled recovery state has been reached for the at least one filter membrane during the first time period; and detecting that the maximum unscaled recovery state has been reached for the at least one filter membrane. The method includes introducing one or more doses of an inhibitor to at least one filter membrane to increase the time between when a filtering recovery condition is reached and when scaling and / or fouling of the at least one filter membrane occurs.

[0166]

[0172] Example 78 is a method of operating a batch reverse osmosis (RO) filtration system having an inlet fluidly coupled to at least one feedstream, at least one filter membrane fluidly coupled to the inlet to receive feedwater for the at least one feedstream, and at least one pump for generating a pressure to move the feedwater for the at least one feed through the at least one filter membrane and generate an output permeate stream, the method including: providing a first drive signal to the at least one pump to increase the generated pressure of the at least one pump to a pressure above the osmotic pressure of the at least one filter membrane to output the output permeate stream at substantially a target recovery rate that is greater than a maximum unscaled recovery rate of the at least one filter membrane during a first time period, thereby maintaining output of the output permeate stream at substantially the target recovery rate; and introducing one or more doses of an inhibitor to the at least one filter membrane at predetermined times during the first time period.

[0167]

[0173] Example 79 includes the features of example 78, wherein the predetermined time point divides the first period into a first induction period occurring before the predetermined time point and a second induction period occurring after the predetermined time point during which one or more doses of scale inhibitor are introduced, the first induction period being a period that acts before scaling and / or fouling occurs, and the second induction period being a period measured from the time when the one or more doses of scale inhibitor are introduced to the time when scaling and / or fouling occurs.

[0168]

[0174] Example 80 is a non-transitory computer-readable medium having stored thereon instructions for performing the method of example 77. Example 81 is a non-transitory computer-readable medium having stored thereon a plurality of instructions for performing the method of example 78 or 79.

[0169]

[0175] Example 82 is a non-transitory computer-readable medium having stored thereon a plurality of instructions for performing a method according to any one of Examples 1 to 40.

[0170]

[0176] While the principles of the present disclosure have been described herein, those skilled in the art will recognize that this description is made by way of example only and is not intended to limit the scope of the present disclosure. Other embodiments in addition to the exemplary embodiments shown and described herein are contemplated within the scope of the present disclosure. Those skilled in the art will recognize that a surface cleaning device may embody any one or more of the features contained herein, and that the features may be used in any specific combination or subcombination. Modifications and substitutions made by those skilled in the art are deemed to be within the scope of the present disclosure, and are not to be limited except as by the appended claims.

Claims

1. 1. A method of operating a filtration system having at least one inlet fluidly coupled to at least one feedstream, at least one filter membrane fluidly coupled to the at least one inlet for receiving feedwater from the at least one feedstream, and at least one pump for generating pressure to move the feedwater from the at least one feedstream through the at least one filter membrane and produce an output permeate stream, comprising: providing a first drive signal to the at least one pump to cause the generated pressure to produce the output permeate stream at a recovery substantially equal to a first target recovery that is greater than a maximum unscaled recovery of the at least one filter membrane and less than 100% for a first time period.

2. 10. The method of claim 1, further comprising: providing a second drive signal to the at least one pump to cause the generated pressure to produce the output permeate stream at a recovery rate substantially equal to a second target recovery rate for a second time period.

3. 3. The method of claim 2, wherein the second target recovery rate is less than or equal to the maximum unscaled recovery rate of the at least one filter membrane.

4. 3. The method of claim 2, wherein the second target recovery rate is greater than the maximum unscaled recovery rate of the at least one filter membrane.

5. 3. The method of claim 2, wherein the second target recovery rate is greater than the maximum unscaled recovery rate of the at least one filter membrane and the first target recovery rate.

6. 3. The method of claim 2, wherein the second drive signal causes at least a partial flush of the at least one filter membrane such that the second target recovery rate is less than the maximum unscaled recovery rate of the at least one filter membrane.

7. 7. The method of claim 6, wherein the second target recovery is equal to zero such that all of the feedwater received in the at least one feedstream is output as reject.

8. 3. The method of claim 2, wherein the second target recovery rate is less than or equal to the maximum unscaled recovery rate of the at least one filter membrane for a portion of the second period of time and greater than the maximum unscaled recovery rate for a portion of the second period of time.

9. 3. The method of claim 2, wherein the second target recovery is greater than 0% and less than or equal to the maximum unscaled recovery to cause partial flushing of the at least one filter membrane.

10. 3. The method of claim 2, wherein the second target recovery is from 96 to 100% such that the volumetric ratio of the received feed water to the output permeate stream is from 0.96 to 1.0 during the second time period.

11. 3. The method of claim 2, further comprising causing at least one bleed valve fluidly coupled to the at least one filter membrane to output a first predetermined portion of the feed water of the at least one feedstream as reject water during the second time period.

12. the second target recovery rate is equal to 100%; 12. The method of claim 11, wherein causing the at least one bleed valve to output the first predetermined portion of the at least one feedstream as reject water during the second period of time further comprises closing the at least one bleed valve such that substantially 0% of the at least one feedstream is output as reject water.

13. the second target recovery rate is less than 100%; 12. The method of claim 11, wherein causing the at least one bleed valve to output the first predetermined portion of the at least one feedstream as reject water during the second time period further comprises opening the at least one bleed valve to output the first predetermined portion of the feedwater as reject water.

14. 3. The method of claim 2, wherein the second target recovery is 100% such that 0% of the at least one feedstream is output as reject water during at least a portion of the second time period.

15. The method of claim 2 , wherein the second period occurs before or after the first period based on a predetermined sequence of filter operations.

16. the second target recovery rate is 100%; causing the at least one pump to provide the second drive signal further includes introducing one or more doses of scale inhibitor to the at least one filter membrane at predetermined times during the second period of time; The predetermined time point divides the second period into a first induction period occurring before the predetermined time point and a second induction period occurring after the predetermined time point during which a scale inhibitor is introduced; the first induction period is a period of time that acts before scaling and / or fouling of the at least one filter membrane occurs; 3. The method of claim 2, wherein the second induction period is a period measured from when the antiscalant is introduced to when scaling and / or fouling of the at least one filter membrane occurs.

17. and causing the at least one pump to provide a third drive signal to at least partially flush the at least one filter membrane; 3. The method of claim 2, wherein causing the at least one pump to provide a third drive signal to at least partially flush the at least one filter membrane further comprises causing the at least one pump to provide the third drive signal for a third time period after the second time period.

18. 20. The method of claim 17, wherein the third drive signal causes the at least one pump to generate a pressure that produces the output permeate stream at a recovery rate substantially equal to a third target recovery rate during the third time period.

19. 20. The method of claim 18, wherein the third target recovery rate is from 0% to 80% during the third period of time to cause at least partial flushing of the at least one filter membrane.

20. 20. The method of claim 18, wherein the third target recovery rate is substantially 0% to cause a complete flush of the at least one filter membrane, and the third target recovery rate is different from the first target recovery rate and the second target recovery rate.

21. the second period follows the first period; 3. The method of claim 2, wherein providing the second drive signal for the second period occurs without an intervening full flush of the at least one filter membrane between the first and second periods.

22. the second drive signal increases the pressure generated by the at least one pump above the osmotic pressure of the at least one filter membrane such that the pressure increases by at least 10 psi per minute over the second period of time; The method of claim 2 , wherein the second period of time is at least two minutes.

23. the second drive signal causes the at least one pump to generate a substantially constant pressure such that the substantially constant pressure increases by up to 10 pounds per square inch (psi) per hour over the second time period; 3. The method of claim 2, wherein the second period of time is at least 6 hours.

24. the first drive signal increases the pressure generated by the at least one pump above the osmotic pressure of the at least one filter membrane such that the pressure increases by at least 10 psi per minute over the first period of time; The method of claim 1 , wherein the first period of time is at least two minutes.

25. the first drive signal causes the at least one pump to generate a substantially constant pressure such that the substantially constant pressure increases by up to 10 pounds per square inch (psi) per hour over the first time period; 10. The method of claim 1, wherein the first period of time is at least 6 hours.

26. 10. The method of claim 1, further comprising causing at least one bleed valve fluidly coupled to the at least one filter membrane to output a second predetermined portion of the feedwater of the at least one feedstream as reject water during the first time period.

27. the first target recovery rate is 98% or less; 27. The method of claim 26, wherein causing the at least one bleed valve to output the second predetermined portion of the feedwater of the at least one feedstream as reject water during the first period of time further comprises opening the at least one bleed valve to output at least 2% of the feedwater of the at least one feedstream as reject water during the first period of time.

28. 2. The method of claim 1, wherein causing the at least one pump to provide the first drive signal further comprises causing one or more doses of scale inhibitor to be introduced to the at least one filter membrane at a predetermined time during the first time period that is a predetermined time at an initial start of the first time period or at a time after the initial start of the first time period and prior to scaling and / or fouling of the at least one filter membrane.

29. The predetermined time point divides the first period into a first induction period occurring before the predetermined time point and a second induction period occurring after the predetermined time point during which a scale inhibitor is introduced; the first induction period is a period of time that acts before scaling and / or fouling of the at least one filter membrane occurs; 30. The method of claim 28, wherein the second induction period is a period measured from when the antiscalant is introduced to when scaling and / or fouling of the at least one filter membrane occurs.

30. 30. The method of claim 29, wherein causing the at least one pump to provide the first drive signal further comprises causing the at least one pump to monotonically increase pressure above the osmotic pressure of the at least one filter membrane from the predetermined time point at which the antiscalant is introduced to maintain the first target recovery rate during at least a portion of the second induction period.

31. at least one inlet fluidly coupled to at least one feedstream; at least one filter membrane fluidly coupled to the at least one inlet for receiving feedwater from the at least one feedstream; at least one pump for generating pressure to move the feed water from the at least one feed stream through the at least one filter membrane and produce an output permeate stream; a controller causing the at least one pump to provide a first drive signal to cause the generated pressure to produce the output permeate stream for a first time period at a recovery substantially equal to a first target recovery greater than a maximum unscaled recovery of the at least one filter membrane and less than 100%; A filter system comprising:

32. 32. The filter system of claim 31 , wherein the controller further causes the at least one pump to provide a second drive signal to the at least one pump to cause the generated pressure to produce the output permeate stream at a recovery rate substantially equal to a second target recovery rate for a second time period.

33. 33. The filter system of claim 32, wherein the second target recovery rate is less than or equal to a maximum unscaled recovery rate of the at least one filter.

34. 33. The filter system of claim 32, wherein the second target recovery rate is greater than the maximum unscaled recovery rate of the at least one filter membrane.

35. 33. The filter system of claim 32, wherein the second target recovery rate is greater than the maximum unscaled recovery rate of the at least one filter membrane and the first target recovery rate.

36. 33. The filter system of claim 32, wherein the second drive signal causes at least a partial flush of the at least one filter membrane.

37. 37. The filter system of claim 36, wherein the second target recovery is equal to zero such that all of the feedwater of the at least one feedstream is output as reject.

38. 37. The filter system of claim 36, wherein the second target recovery rate is less than or equal to a maximum unscaled recovery rate of the at least one filter membrane during a portion of the second time period and greater than the maximum unscaled recovery rate during a portion of the second time period.

39. 37. The filter system of claim 36, wherein the second target recovery rate is greater than 0% and less than the maximum unscaled recovery rate to cause a partial flush of the at least one filter membrane.

40. 33. The filter system of claim 32, wherein the second target recovery is between 96 and 100% such that the volumetric ratio of the received feed water to the output permeate stream is between 0.96 and 1.0 during the second time period.

41. 33. The filter system of claim 32, further comprising at least one bleed valve fluidly coupled to said at least one filter membrane for outputting a first predetermined portion of said feedwater of said at least one feedstream as reject water during said second time period.

42. the second target recovery rate is equal to 100%; 42. The filter system of claim 41, wherein the controller causes the at least one bleed valve to close so that the first predetermined portion of feed water output as reject water is zero percent during the second period of time.

43. 42. The filter system of claim 41, wherein said second target recovery is 100% such that 0% of said at least one feedstream is output as reject water during said second time period.

44. 42. The filter system of claim 41, wherein the second period occurs before or after the first period based on a predetermined sequence of filter operations stored in memory.

45. 33. The filter system of claim 32, wherein the second drive signal further causes one or more doses of antiscalant to be introduced to the at least one filter membrane at predetermined times during the second period of time.

46. The predetermined time point divides the second period into a first induction period occurring before the predetermined time point and a second induction period occurring after the predetermined time point during which a scale inhibitor is introduced; the first induction period is a period of time that acts before scaling and / or fouling of the at least one filter membrane occurs; 46. ​​The filter system of claim 45, wherein the second induction period is a period measured from when the antiscalant is introduced to when scaling and / or fouling of the at least one filter membrane occurs.

47. 33. The filter system of claim 32, wherein the controller further causes the at least one pump to provide a third drive signal to cause at least a partial flush to occur during a third period of time after the second period of time.

48. 48. The filter system of claim 47, wherein the third drive signal causes the at least one pump to generate a pressure that produces the output permeate stream at a recovery rate substantially equal to a third target recovery rate during the third time period, the third target recovery rate being different from the first and second target recoveries.

49. 48. The filter system of claim 47, wherein said third target recovery rate is from 0% to 80% during said third time period to cause at least partial flushing of said at least one filter membrane.

50. 49. The filter system of claim 48, wherein the third recovery rate is substantially 0% to cause a complete flush of the at least one filter membrane.

51. the second period follows the first period; 33. The filter system of claim 32, wherein providing the second drive signal for the second time period occurs without an intervening full flush of the at least one filter membrane between the first and second time periods.

52. the second drive signal increases the pressure generated by the at least one pump above the osmotic pressure of the at least one filter membrane such that the pressure increases by at least 10 psi per minute over the second period of time; 33. The filter system of claim 32, wherein the second period of time is at least two minutes.

53. the second drive signal causes the at least one pump to generate a substantially constant pressure such that the substantially constant pressure increases by up to 10 pounds per square inch (psi) per hour over the second time period; 33. The filter system of claim 32, wherein the second period of time is at least six hours.

54. the first drive signal increases the pressure generated by the at least one pump above the osmotic pressure of the at least one filter membrane such that the pressure increases by at least 10 psi per minute over the first period of time; 32. The filter system of claim 31, wherein the first period of time is at least two minutes.

55. the first drive signal causes the at least one pump to generate a substantially constant pressure such that the substantially constant pressure increases by up to 10 pounds per square inch (psi) per hour over the first time period; 32. The filter system of claim 31, wherein the first period of time is at least six hours.

56. 32. The filter system of claim 31, further comprising at least one bleed valve fluidly coupled to said at least one filter membrane for outputting a second predetermined portion of feedwater of said at least one feedstream as reject water during said first time period.

57. the first target recovery rate is 98% or less; the first predetermined portion of feed water is at least 2%; 57. The filter system of claim 56, wherein the controller causes the at least one bleed valve to output the first predetermined portion of the feedwater of the at least one feedstream output during the first time period as reject water.

58. 32. The filter system of claim 31, wherein the controller further causes one or more doses of antiscalant to be introduced to the at least one filter membrane at predetermined times during the first period of time.

59. The predetermined time point divides the first period into a first induction period occurring before the predetermined time point and a second induction period occurring after the predetermined time point during which a scale inhibitor is introduced; the first induction period is a period of time that acts before scaling and / or fouling of the at least one filter membrane occurs; 60. The filter system of claim 58, wherein the second induction period is a period measured from when the antiscalant is introduced to when scaling and / or fouling of the at least one filter membrane occurs.

60. 60. The filter system of claim 59, wherein causing the at least one pump to provide the first drive signal further comprises causing the at least one pump to monotonically increase a pressure above the osmotic pressure of the at least one filter membrane from the predetermined time point at which the antiscalant is introduced to maintain the first target recovery rate during at least a portion of the second induction period.

61. 32. The filter system of claim 31, wherein the at least one filter membrane comprises at least one high-pressure filter membrane with a pressure casing capable of withstanding a pressure of at least 90 bar.

62. 32. The filter system of claim 31, wherein the at least one filter membrane comprises at least first and second filter membranes, each providing at least a portion of a first and second filter stage, respectively.

63. 63. The filter system of claim 62, further comprising a filter valve device for switchably fluidly coupling said first and / or second filter membranes to said at least one feed stream.

64. 64. The filter system of claim 63, wherein the controller further causes the filter valve device to switchably fluidly couple the first and / or second filter membranes to the at least one feed stream during the first and / or second time periods.

65. 32. The filter system of claim 31, wherein the at least one inlet is fluidly coupled to a bleed of a filter system such that the at least one feed stream comprises a concentrate from the filter system.

66. 32. The filter system of claim 31, wherein said at least one inlet is fluidly coupled to an outlet of a filter system such that said at least one feed stream comprises permeate output by said filter system.

67. 1. A method of operating a filtration system having an inlet fluidly coupled to at least one feedstream, at least one filter membrane fluidly coupled to the inlet for receiving feedwater for the at least one feedstream, and at least one pump for generating pressure to move the feedwater for the at least one feedstream through the at least one filter membrane and produce an output permeate stream, comprising: causing the at least one pump to provide a first drive signal to increase the pressure generated by the at least one pump above the osmotic pressure of the at least one filter membrane and maintain a target recovery rate for a first period of time that exceeds a maximum non-scaling recovery rate and has an associated period of time before reaching a maximum non-scaling recovery state for the at least one filter membrane; detecting that the maximum non-scaling recovery condition has been reached for the at least one filter membrane during the first time period; in response to detecting that the maximum non-scaling recovery condition has been reached, introducing one or more doses of scale inhibitor to the at least one filter membrane to increase the time between when the maximum non-scaling recovery condition is reached and when scaling and / or fouling of the at least one filter membrane occurs; A method comprising:

68. 1. A method of operating a batch reverse osmosis (RO) filtration system having an inlet fluidly coupled to at least one feed stream, at least one filter membrane fluidly coupled to the inlet for receiving feedwater for the at least one feed stream, and at least one pump for generating pressure to move the feedwater for the at least one feed through the at least one filter membrane and produce an output permeate stream, comprising: providing a first drive signal to the at least one pump to increase the pressure generated by the at least one pump above an osmotic pressure of the at least one filter membrane to output the output permeate stream at substantially a target recovery rate greater than a maximum unscaled recovery rate of the at least one filter membrane during a first time period, thereby maintaining output of the output permeate stream at substantially the target recovery rate; introducing one or more doses of scale inhibitor into the at least one filter membrane at predetermined times during the first period of time; A method comprising:

69. The predetermined time point divides the first period into a first induction period occurring before the predetermined time point and a second induction period occurring after the predetermined time point during which the one or more doses of scale inhibitor are introduced; the first induction period is a period that acts before scaling and / or fouling occurs; 69. The method of claim 68, wherein the second induction period is the period measured from the time the one or more antiscalant doses are introduced to the time scaling and / or fouling occurs.

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