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

Abstract

The present disclosure relates to a filtration system. The filtration system comprises: at least one inlet; at least one filtration membrane; at least one pump and a controller configured to: cause a first drive signal to be provided to the at least one pump to cause a generated pressure to produce the output permeate stream at a recovery rate substantially equal to a first target recovery rate for a first time period, the first target recovery rate being greater than a maximum non-fouling recovery rate of the at least one filtration membrane and less than 100%, and cause one or more doses of a scale inhibitor to be introduced into the at least one filtration membrane at a predetermined time within the first time period. The system combines elements of continuous and batch NF / RO based on the limitations of an end-user facility to achieve a target balance between, for example, recovery rate and power consumption, and to reduce long-term operating costs for a plant. Also disclosed herein is a system for extending a batch operation to a second priming period by injecting a scale inhibitor, which allows for a higher water recovery rate.

Description

[0001] This application is a divisional application of PCT international application No. PCT / US2020 / 034674 entitled “Technology for managing fouling formation in water filtration systems and reverse osmosis (RO) and nanofiltration (NF) systems implementing the same”, which entered the Chinese national phase with application No. 202080100949.2.

[0002] Cross-references to related applications

[0003] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 991,393, filed on March 18, 2020, which is incorporated herein by reference in its entirety. Technical Field

[0004] This manual relates to filtration systems and the management of dirt formation within them. Background Technology

[0005] Water filtration systems typically include at least one filter membrane for producing permeate from the feed stream. One approach to water filtration employs steady-state continuous reverse osmosis (RO) operation / circulation and a pump that transfers the feed through one or more filter membranes at a substantially constant pressure. The ratio of the feed present as permeate to the feed present as retentate / retained material determines the system's recovery rate. Such continuous flow systems typically operate at a recovery rate equal to or lower than the rate that induces scaling. Therefore, continuous flow systems have relatively low maximum recovery rates, such as 50-75%, to avoid scaling and fouling.

[0006] Another approach to water filtration is batch RO operation / recirculation. In batch RO, the pump changes pressure over time to overcome the osmotic pressure of one or more filter membranes. Compared to continuous flow systems, batch RO systems offer relatively high recovery rates, but such systems must be periodically flushed to maintain permeate flux. Attached Figure Description

[0007] The various aspects and features of this disclosure will be better understood by reading the following detailed description in conjunction with the accompanying drawings, in which:

[0008] The accompanying drawings included herein are used to illustrate various examples of items, methods, and apparatus for the teachings of this specification and are not intended to limit the scope of the teachings in any way.

[0009] Figure 1 An example diagram of a filtration system continuum is shown, which has relative extremes representing continuous RO operation and batch RO operation, respectively.

[0010] Figure 2AA block diagram of an example filter structure for use in continuous RO operation is shown.

[0011] Figure 2B A block diagram of an example filter structure for use in a batch RO operation is shown.

[0012] Figure 3 A block diagram of an example filtering system according to an embodiment of the present disclosure is shown.

[0013] Figure 4 An embodiment of the present disclosure is shown for use via Figure 3 The order of several example filtering operations performed by the filtering system.

[0014] Figure 5 An embodiment of the present disclosure is shown for performing Figure 4 Example process steps of one or more filtering operation sequences.

[0015] Figure 6 This illustrates how, when operated at a recovery rate higher than the non-fouling rate according to the embodiment, a first initiation period and a second initiation period are generated to prolong the process. Figure 3 An example process for the operation of a filtration system.

[0016] Figure 7 This illustrates the sequence of one or more filtering operations performed according to embodiments of this disclosure. Figure 3 The curves of various recovery target rates of the filtration system over time (T).

[0017] Figure 8 This illustrates the sequence of one or more filtering operations performed according to embodiments of this disclosure. Figure 3 Another graph showing the recovery target rates of the filtration system over time (T). Detailed Implementation

[0018] The popularity and adoption of RO-based filtration systems continue to increase, especially in commercial and large-scale filtration plants. RO-based water filtration systems fall into one of two operating modes: continuous RO or batch RO. Although both modes of RO filtration systems use similar filtration technologies, such as NF, seawater RO, and brackish water RO, filtration systems implementing continuous RO operation and those implementing batch RO operation are located at opposite ends of a continuum.

[0019] This continuum can be better understood through diagrams. Figure 1An example of such a continuous system is shown, featuring continuous and batch RO operations at opposite ends / extremes. Specifically, the continuous RO system operates at relatively low recovery rates to achieve a non-fouling stable state (with or without antiscalant), with its operating time measured in weeks to months. On the other hand, the batch RO system operates at recovery rates higher than the non-fouling stable state (i.e., 100% recovery), and its operating time is typically a fraction of the time the continuous RO system operates before the filter membrane is flushed (e.g., through the feed). For example, some batch RO operations last only a few minutes to a few hours before the flushing cycle takes place.

[0020] Compared to batch RO systems, continuous RO systems are characterized by different structures and operational differences. New and existing filter designs implement batch RO when high recovery rates are required, and continuous operation when stable, uninterrupted operation for weeks or months is needed. No or low scale inhibitor dosage is preferred, and / or reduced water recycling is acceptable.

[0021] In either case, the design of a water filtration system employing NF and RO technologies typically begins by determining the maximum recovery setpoint (also referred to herein as water recovery rate, recovery rate, or simply recovery) based on the recovery rate at which scaling begins to occur on the selected filter membrane. This identified recovery rate is usually calculated without the use of scale inhibitors (also referred to herein as antiscalants). The recovery rate of a filtration system is expressed as the ratio defined by the portion of the feed (or feed water) entering the filtration system to the portion of the feed leaving as permeate. Therefore, a recovery rate below 100% includes at least a portion of the feed that is discharged as product residue (also referred to herein as retained water or simply retained product) through one or more drain valves.

[0022] Therefore, product residue, also referred to herein as residue, refers to the portion of the feed that does not pass through the filter membrane. On the other hand, permeate refers to the portion of the feed that passes through the filter membrane as, for example, “clean” water output, although permeate may not necessarily be drinking water, depending on the structure of the filtration system and the intended use of the permeate.

[0023] It should be noted that the following disclosures generally refer to the point at which scaling reaches the supersaturation point of fouling-forming compounds, and when fouling reaches the critical flux (or critical concentration), at which point permeate output is significantly reduced or otherwise blocked, referred to as scaling and fouling, respectively. Some examples and scenarios discussed herein may refer to one or both of these scaling and fouling conditions, and not necessarily both. For example, various aspects and features disclosed herein relate to the maximum non-scaling recovery rate. This value is not limited to scaling but may also refer to the maximum rate prior to the presence of fouling conditions.

[0024] In the case of a continuous RO / NF system, such as Figure 2A As shown, the maximum recovery rate (or setpoint) is established at a rate just below the recovery rate identified when scaling conditions begin to occur. Alternatively, as discussed in further detail below, the maximum recovery rate setpoint can be operated above the recovery rate identified when scaling conditions occur when an antiscalant is used. In either case, the continuous RO / NF system then operates in a non-scaling stable state for a period of time, typically measured weekly / monthly. During operation, the continuous RO / NF system consumes substantially constant power, for example, by loading the feed stream through the filter membrane via a pump, and the resulting product residue is then treated via a sewer or provided to an additional filtration stage, which further increases the operating cost of such a system. Continuous RO / NF systems typically operate at a fixed recovery rate of approximately 50%–70% to maintain a non-scaling stable state.

[0025] Conversely, in the case of batch RO / NF systems, such as Figure 2B As shown, the maximum recovery rate (or setpoint) is set above the recovery level identified when scaling conditions begin to occur. This configuration enables cyclic batch operation, where 100% of the feed is converted into permeate after a period of time, after which the RO system is flushed with the feed to remove the final batch concentrate from the run, and then the batch cycle restarts.

[0026] For example, using batch RO / NF, a maximum recovery rate of 100% can be set, eliminating the need for discharge to remove product residues. The RO / NF system is set at this recovery rate and then operated in a non-steady-state condition, with the pressure varying over time to overcome the osmotic pressure of the filter membrane. The total amount of time spent in this non-steady-state operation can be measured in minutes or hours, depending on the specific configuration of the filtration system. One advantage of batch RO is that high recovery rates can be achieved without the use of antiscalants.

[0027] However, at some point during this batch operation, the osmotic pressure of the filter membrane will exceed the maximum pressure the system's pump can generate. System designers typically limit the amount of time that the system operates in this unstable state—that is, outside the scaling limits—to avoid potential damage and / or unsafe conditions to the filtration system. This limitation may include, for example, carefully monitoring system pressure and / or preventing operation in the unstable state for more than a fixed, predetermined amount of time. Therefore, a high recovery rate, i.e., 100%, is achieved at the cost of downtime for rinsing the filter membrane (and a reduced recovery rate), as well as additional wear and tear on the pump due to high-frequency batch cycling.

[0028] Over the past two decades, scale inhibitors have seen significant improvements, resulting in higher recovery rates for both batch and continuous RO systems. Table 1 below shows the maximum 100% supersaturation values ​​of various commercially available scale inhibitors relative to no scale inhibitor, or the maximum absolute concentration of the major scaling compounds, or the maximum Langerier saturation index (LSI) (in pH) relative to saturation pH for calcium carbonate fouling in certain NF / RO retentate streams, making them supersaturated by %. In Table 1, the maximum supersaturation reported from one example publicly available source is shown in column 2, but it should be noted that results may change over time as scale inhibitor research progresses.

[0029] Commercial / large-scale NF / RO systems typically operate at fixed feed and recovery rates (resulting in fixed permeate and effluent rates), and these systems use antiscalants added to the feed to achieve supersaturation. Antiscalant dosages are typically 5 mg / L or less to reduce chemical costs. However, market demand for higher recovery rates and wastewater reuse continues to increase. Increasing antiscalant dosages remains the primary means of meeting these demands. Simultaneously, these market demands also lead to higher membrane fouling rates and associated chemical costs.

[0030] Several challenges also exist related to handling NF / RO effluent streams containing antiscalants. These challenges include the need for post-treatment of these streams in settling and thermal reduction systems, and / or the impact of antiscalants on the receiving streams in the environment. Additional challenges include potential incompatibility between the membrane and the antiscalant, and unintended harmful interactions between the feed stream components and the antiscalant, one or both of which can degrade the performance of the filtration system.

[0031] Table 1

[0032] LSI (calcium carbonate) +2.9 Calcium sulfate 400％ Strontium sulfate 1200％ Barium sulfate 8000％ Calcium fluoride 12000％ silicon dioxide 300 ppm or higher iron 5ppm aluminum 4ppm

[0033] The continuous improvement of water filtration systems using RO technology depends at least in part on the development of filtration technologies that enable the features and advantages of continuous RO and batch RO systems to be integrated in a way that achieves relatively high recovery rates without the existing disadvantages of such rates, such as wear and tear on system components, high power consumption, and the need to use scale inhibitors.

[0034] In addition, there is a need for filtration systems, which in a general sense can be described above regarding... Figure 1 The discussion operates at the midpoint of the continuum to balance multiple target parameters, such as total power consumption, wastewater generation, and other costs in the system design, in order to achieve the desired water recovery rate, which also meets various other requirements and objectives specific to the particular filtration system.

[0035] In light of the foregoing, this disclosure relates to techniques (e.g., systems and methods) that combine elements of continuous and batch NF / RO. Such systems and methods can take into account the limitations of end-user facilities to achieve, for example, a target balance between recovery rate and power consumption, and to reduce long-term plant operating costs. This document also discloses methods for extending batch operation to a second initiation period by injecting an antiscalant, which enables higher water recovery rates. The first and / or second initiation periods can preferably be extended by using a high-pressure filtration membrane module and a pump capable of generating variable pressures up to 90-120 bar, for example, to displace feed water through the high-pressure filtration membrane module. In addition to scaling, the techniques disclosed herein can also be used for fouling management, as fouling similarly has a negative impact on the pressure and recovery of NF / RO systems.

[0036] Unless otherwise specified in this invention, the term "substantially" when used to refer to the quality, characteristic, or value means ±10% of the quality, characteristic, or value.

[0037] As used herein, the term "coupling" refers to any connection, linkage, link, etc., while "fluid coupling" refers to a coupling that enables fluid from one element to communicate with another element. Such "coupled" elements are not necessarily directly connected to each other and can be separated by intermediate components / elements. Similarly, the term "direct coupling" refers to a connection between elements without the use of intermediate components, and as used herein, "direct fluid coupling" refers to the coupling of elements where fluid can be transferred from one element to another without the use of intermediate components / elements.

[0038] Turn to the attached diagram. Figure 3 An example of a filtration system 300 consistent with this disclosure is shown. As shown, the filtration system 300 includes a controller 302, at least one pump 304, and a filtration stage 306.

[0039] Controller 302 includes at least one processing device / circuit, such as a microcontroller (MCU), digital signal processor (DSP), field-programmable gate array (FPGA), reduced instruction set computer (RISC) processor, ×86 instruction set processor, microcontroller, or application-specific integrated circuit (ASIC). Preferably, controller 302 is implemented within a programmable logic controller (PLC). Controller 302 is preferably communicatively coupled to at least one pump 304. Controller 302 can be configured to provide drive signals to pump 304 to cause pump 304 to generate a target amount of pressure.

[0040] The controller 302 is also preferably communicatively coupled to at least one discharge valve, such as discharge valve 308. The controller 302 can be configured to provide a control signal to discharge valve 308. Preferably, the control signal is configured to switch discharge valve 308 between a closed position and a plurality of open positions. Each of the plurality of open positions allows different amounts of feed water from feed flow 309 to be output as product retentate 310 (also referred herein as concentrated retentate, retentate water, or simply retentate). As discussed further below, and according to one embodiment, filter valve arrangement 312 can switchably couple feed fluid transferred by at least one pump 304 to one or more filter stages 314 (also referred herein as filter array). Therefore, the controller 302 can be configured to provide a control signal to valve arrangement 312 that switches one or more filter stages 314 to the feed transferred by at least one pump 304.

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

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

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

[0044] The at least one filter membrane 311 further includes at least one outlet 311-2 for discharging permeate 313 and at least one discharge port 311-3 for discharging retentate 310. The outlet 311-2 of the at least one filter membrane 311 may, for example, be fluidly coupled to the inlet of another filter stage in the plurality of filter stages 314 for further treatment, depending on the desired configuration. The at least one discharge port 311-3 may also be fluidly coupled to the inlet of another filter stage in the plurality of filter stages 314, or optionally fluidly coupled to a sewage pipe / wastewater return port.

[0045] In one embodiment, filter stage 306 may optionally be implemented as a plurality of different filter stages, such as filter stages 314-1 to 314-2, collectively shown in 314. Each of the plurality of filter stages 314 may further include filter membranes substantially similar to or of different types relative to the other filter stages and / or a total number of filter membranes. For example, first filter stage 314-1 may be configured with one or more filter membranes of a first type, and second filter stage 314-2 may be configured with one or more filter membranes of a second type, the second type having a pressure housing capable of withstanding a higher maximum operating pressure than the first type of filter membrane. This change in filter type is particularly advantageous when high-pressure cycling is performed through second filter stage 314-2. In this case, valve arrangement 312 may switchably couple feed fluid from at least one pump 304 to second filter stage 314-2 and switchably decouple feed fluid from the other filter stages of the plurality of filter stages 314 (e.g., first filter stage 314-1), the other filter stages of the plurality of filter stages 314 not necessarily having a pressure housing capable of withstanding a specific amount of pressure during high-pressure cycling.

[0046] The filter valve arrangement 312 can be implemented as an electromechanical valve configured to be actuated by a received control signal as described above. However, the filter valve arrangement 312 can be implemented by other suitable devices including a manual valve, or a combination of such a manual valve and an electromechanical valve, which requires actuation by a user-supplied force, for example, by a technician or engineer.

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

[0048]

[0049] Consider the following scenario: the filtration system is flushed at gallons per minute (gpm) for 3 minutes, while simultaneously running at 100 gpm for 30 minutes during batch production. The total recovery rate of the filtration system 300 can then be 88.9% = (100 gpm × 30 min) / (100 gpm × 30 min + 125 gpm × 3 min). One advantage of batch RO treatment is that the filtration system can operate without antiscalants and exceed the maximum recovery rate by running for a period of time without scaling, where this period is shorter than the time required from the onset of scaling / fouling conditions to the occurrence of scaling, referred to here as the first initiation period.

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

[0051] The designer then selects a membrane, preferably one with specific fouling and TDS rejection characteristics. For example, a brackish water RO membrane with a 99.5% TDS rejection rate can be selected for both TDS and scaling rejection.

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

[0053] The designer then determines the first initiation time based on factors such as the temperature and other pretreatment feed conditions expected to be implemented on the filtration system (e.g., antiscalant dosage, acid dosage), for example, the time between when the maximum non-scaling recovery rate is reached (or first exceeded) and when scaling actually occurs. For example, the first initiation time could be equal to 25 minutes.

[0054] The designer can then optionally determine the feed / retention capacity of the filtration system. For example, the filtration system could be designed to have a feed / retention capacity of 200 gallons.

[0055] The designer then preferably establishes multiple inputs (or operating parameters), including, for example, dynamic water / carrying fluid characteristics, fouling, contaminants, and TDS (total dissolved solids), to generate a mass balance that allows tracking of the carried fluid (e.g., water and components) entering the system and the emissions and permeates leaving the system. Note that the emission rate is preferably set by the designer as an input. This mass balance shows the concentration of the aforementioned parameters in the system over time and preferably tracks the recovery rate over time.

[0056] The designer can then analyze the output and filtration system performance of the aforementioned quality balance based on changes to the various inputs / parameters described above, and preferably select operating parameters for the filtration system that set the recovery rate between 100% recovery rate and a maximum non-fouling recovery rate, which achieves the desired power consumption rate (and by extending costs) and the average recovery rate of the filtration system. Preferably, the selected operating parameters also take into account wastewater / residue treatment costs and / or peak power consumption (e.g., peak current when the pumps of the circulating filtration system are used for flushing, batch circulation, etc.). The designer can also update or otherwise modify the selected operating parameters to change the operating setpoint as the conditions of the filtration system change (e.g., increase / decrease wastewater treatment costs, increase / decrease electricity costs, and / or increase / decrease recovery rate targets).

[0057] Then, the selected operating parameters can preferably be output as machine-readable instructions, which, when executed by a controller such as controller 302, cause a series of filtering operations to occur, such as... Figure 4 One or more filtering sequences are shown and discussed in further detail below. Such instructions may preferably be stored in the memory (not shown) of the controller 302.

[0058] Extended initiation period of RO / NF filtration system

[0059] This disclosure also recognizes that a second initiation period can be established by introducing an antiscalant at a predetermined time before the end of the first initiation period (e.g., when scaling / fouling occurs). This disclosure further establishes that the total recovery achieved by the operation of the filtration system 300 during both the first and second initiation periods allows the filtration system 300 to achieve a higher total recovery rate than that achievable by using the antiscalant alone during batch / continuous RO cycles. Such a first and second initiation period can be incorporated into the filtration system design process, such as the example filtration system design process described above.

[0060] Note that, as described above, the feed 309 entering filter stage 306 may originate from retentate / stagnant streams from another filter stage / system. In this case, feed 309 may include an antiscalant. Then, when determining the dosage to initiate a second initiation period as disclosed herein, the concentration / amount of the antiscalant present in feed 309 and its known efficiency can be utilized. For example, the antiscalant may have a time-dependent efficiency, potentially requiring more and / or less antiscalant dosage to initiate the second initiation period, and more importantly, extending the total duration of the second initiation period.

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

[0062] In one embodiment, the filtration system 300, with or without scale inhibitors, implements batch RO characteristics in a portion of the circulation, having a recovery rate set between 100% recovery and a non-scaling stable state. Preferably, the filtration system 300 performs at least one filtration operation at a recovery rate set greater than the maximum non-scaling recovery rate and less than 100% recovery. This operation can be referred to herein as substantially continuous operation because the recovery rate can be set to a ratio higher than the maximum non-scaling recovery rate, with at least a portion of the feed water output as retentate. In contrast, continuous operation includes a recovery rate set equal to or less than the maximum non-scaling recovery rate, and batch operation includes a recovery rate set to 100% (i.e., no retentate discharge). Thus, filtration systems consistent with this disclosure allow recovery rates higher than those of similar continuous systems but lower than those of similar batch RO systems to achieve a balance of operating parameters such as total power consumption and wastewater pipe costs.

[0063] In embodiments, batch RO and continuous operation / cycle can be performed in a predetermined sequence of filtration operations to meet various end-user requirements, such as total recovery rate (e.g., average over a predetermined time period), power consumption, and associated costs, such as wastewater pipe / disposal costs for treating intercepted water, as discussed above.

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

[0065] In addition, it should be noted that the filter 300 system may use one or more energy recovery devices, such as turbochargers or pressure exchangers, and in combination with the various filtration processes disclosed herein to further improve power efficiency and reduce total power consumption.

[0066] In view of the foregoing, one aspect of this disclosure is to determine the optimal recovery rate and power consumption for RO and NF treatment of scaled water by sequencing batch and / or continuous RO operations. Various features and aspects of this disclosure preferably allow for enhancement / improvement of existing filtration systems to, for example, better control and adjustment of power consumption and total recovery rate. However, this disclosure is equally applicable to new filtration system designs and is not necessarily limited thereto.

[0067] Figure 4 Several example sequences (AC) are shown, among which Figure 3The operation of the filtration system 300 may include: operation according to sequence A, B, C, or any combination thereof, depending on, for example, the desired total recovery rate, power consumption, and retained / retained output. For example, operation may include sequence A and B without sequence C, or include sequence A and C without sequence B.

[0068] During operation, each selected sequence may include executing each of the phases shown in times I, II, and III, or only a subset of these phases. For example, sequences A and C may be executed optionally, without necessarily executing the flushing phase in time III. Similarly, sequences may be executed out of order, and sequence A may not necessarily be executed before B, and similarly, C may not necessarily be executed after B, for example, it may be executed after A instead. A sequence may be repeated N times, such that a given sequence is repeated a predetermined number of times without any other sequence in between. Therefore, a particular combination of sequences may include one or more selected sequences, wherein the selected sequences are executed in a desired order, and preferably in an order capable of achieving one or more performance objectives (e.g., total recovery rate and power consumption). A particular sequence may preferably be stored as machine-readable code (e.g., a setup file). Figure 3 The filter system 300 is stored in a memory (not shown).

[0069] It should be noted that sequence C allows for a continuous phase as an incomplete flushing (also referred to herein as partial flushing) operation of the filtration system 300 following the batching phase at time (I), thus allowing for a reduction in the total number of operating cycles of the filtration system 300 relative to a system that performs flushing after each batch RO cycle. An example of this partial flushing is referenced [reference needed]. Figure 8 As shown and discussed below, this partial flushing can advantageously increase the operational life of the filtration system by reducing wear on pumps and related equipment, as well as by reducing the time periods during which the filtration system does not output permeate (e.g., at 0% recovery rate). This also advantageously provides more stable operating conditions for the end user and higher power efficiency for the filtration system by reducing energy losses caused by various filtration system components, such as current spikes / surges caused by circulating at least one pump 304. Such energy losses can significantly reduce the power efficiency of the filtration system because they accumulate over the system's lifespan and can ultimately represent a significant source of power loss, especially for high-current motors in commercial / large-scale filtration systems.

[0070] Figure 5 An example process 500 is shown to illustrate various aspects and features of this disclosure. In particular, process 500 includes operations that cause a filtration system conforming to this disclosure to perform continuous operation / cycles, followed by batch operation / cycles, for example, as... Figure 4Example sequence A is shown. However, process 500 is not necessarily limited to this and other sequences, and combinations of sequences are within the scope of this disclosure.

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

[0072] However, process 500 can also be performed manually, for example, by a user manually actuating a switch to send a control signal to at least one discharge valve 308 and / or filter valve arrangement 312, or by a combination of automatic and manual steps. For example, controller 302 can be configured to cause at least one pump to generate a target pressure via an automatic sequence, while discharge valve 308 can be manually actuated by a technician to achieve the desired recovery rate. Notably, controller 302 can be configured to provide visual indicators based on a timer / timetable, such as via a user interface of a computer system, LED lights, etc., to enable a technician to perform one or more manual steps / processes, such as actuating at least one discharge valve 308.

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

[0074] In operation 504, controller 302 causes at least one discharge valve 308 to output a predetermined portion of the feed stream, such as feed stream 309, as retained / retained material within a first time period based on a first target recovery rate. For example, in one embodiment, a recovery rate of 80% is set as the first target recovery rate, therefore, at least one discharge valve 308 can be configured to output 20% of the feed stream as retained material.

[0075] In operation 506, controller 302 provides a drive signal (or a first drive signal) to at least one pump, such as pump 304, to generate an output permeate stream over a first time period based on a determined first target recovery rate. In one embodiment, the first drive signal is configured to cause at least one pump to generate a substantially constant pressure such that the pressure increases by a maximum of 10 psi per hour from the initial pressure required to achieve the target recovery rate during the first time period. In one embodiment, the first time period is 1-2 hours, preferably at least 6 hours. Note that during substantially continuous operation, the rate of pressure change varies based on multiple factors, including, for example, feed water characteristics and / or the recovery rate setpoint. For example, during substantially continuous operation, a 99% recovery rate will result in a relatively higher pressure increase per minute compared to operation at a 90% recovery rate. Therefore, the example pressure values ​​and rates of change provided herein in relation to substantially continuous operation are not provided for limiting purposes.

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

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

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

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

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

[0081] Preferably, the second drive signal is configured to cause 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, during a second time period. In one embodiment, the second time period is at least two (2) minutes.

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

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

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

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

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

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

[0088] Figure 7To illustrate when executed separately Figure 5 and Figure 6 Example coordinate graph 700 shows the operation of filtration system 300 during process steps 500 and 600. Coordinate graph 700 includes the target recovery rate range from 0% to 100% along the Y-axis, and time along the X-axis. In this example sequence, according to... Figure 5 In process 500, operations 502-506, the filtration system 300 operates for a first time period (T0 to T0+1) at a first target recovery rate (e.g., 80%). As shown, this first target recovery rate can preferably be selected as a ratio higher than the predetermined maximum non-fouling / fouling recovery rate of at least one filter membrane 311 of the filtration system 300.

[0089] After the first time period ends (e.g., T0+1), the filtration system 300 operates for a second time period (e.g., T0+1 to T0+2, or T0+1 to T0+3) at a second target recovery rate (e.g., 98%). The second time period defines at least a first initiation period, which is the time between when the filtration system 300's recovery rate exceeds the non-fouling / fouling recovery rate (e.g., the recovery rate at the onset of fouling / fouling conditions) and when fouling / fouling occurs. In other words, during the second time period, the target recovery rate exceeds the maximum non-fouling recovery rate of the filtration system 300 and has a relevant duration before one or more filter membranes reach the maximum non-fouling recovery rate state without intentional injection of an antiscalant, which may also be referred to as the pre-antiscalant maximum non-fouling recovery rate state. As shown, the filtration system 300 reaches the pre-antiscalant maximum non-fouling recovery rate state only after T0+2 during the first initiation period. Note that, as mentioned above, scale inhibitors may be present in the feed, and the use of the term scale inhibitor does not preclude the presence of such existing scale inhibitors.

[0090] As further shown, the filtering system 300, and more specifically, the controller 302, can be, for example, based on... Figure 6 The operation 606 of process 600 determines a predetermined time, such as that shown at T0+2, which is exactly before the state of maximum non-scaling recovery before the scale inhibitor is reached, for example, when scaling / fouling occurs during the first initiation period.

[0091] At a predetermined time, controller 302 can, for example, be based on the above description. Figure 6The operation 608 of process 600 introduces / injects a scale inhibitor dose into at least one filter membrane 311. In response, the operation of the filtration system 300 at the second target recovery rate can then continue during the second initiation period until, for example, 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 amount of time for the operation of the filtration system 300 during the second initiation period has elapsed, in order to avoid the filtration system 300 operating under unstable conditions.

[0092] For example, introducing an antiscalant at a predetermined time extends the maximum non-scaling recovery rate state of the filtration system 300 to T0+3. This extended recovery state is also referred to as the post-antiscalant maximum non-scaling recovery rate state. This extended duration allows the osmotic pressure of at least one filter membrane to exceed the maximum pressure that can be generated by at least one pump 304 and / or the maximum pressure rating of the filter membrane before reaching the end of the second initiation period (e.g., T0+3). Therefore, the filtration system 300 can preferably be configured to continue batch operation for a predetermined maximum amount of time during the second initiation period at a second target recovery rate, wherein the predetermined maximum amount of time is less than the total duration of the second initiation period provided by the dosage of antiscalant introduced at the predetermined time. The predetermined maximum amount of time can be selected as a constant duration, e.g., 1 minute, 3 minutes, 1-30 minutes, or can be dynamically set based on, for example, the dosage of the antiscalant, and / or known antiscalant performance ratings, and / or known feed conditions, pressure or other equipment limitations, and / or permeate or retentate quality requirements (retentates can be measured online, for example, by Internet of Things (IoT) devices).

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

[0094] Figure 8 To illustrate the implementation according to the embodiment Figure 5 Example coordinate graph 800 shows the operation of the filtration system 300 during process 500. Graph 800 includes target recovery rates from 0% to 100% along the Y-axis and time along the X-axis. In this example case, the filtration system 300 operates sequentially, comprising essentially continuous operation at a first recovery rate target (above the maximum non-fouling recovery rate but below 100% recovery rate) and batch operation at a second recovery rate target (100% recovery rate). This sequence also includes optional backwashing cycles, as described below.

[0095] As shown in the figure, the total duration of each basic continuous operation is D1, and the total duration of each batch operation is D2. D1 can be measured in terms of at least 6 hours, preferably in terms of at least one day. On the other hand, D2 can be measured in terms of from at least one minute to several hours, preferably in terms of at least 5 minutes. Therefore, the duration of D1 can be significantly longer than that of D2.

[0096] The duration D1 of each basic continuous operation can be uniform or can be varied such that each operation is longer than, substantially equal to, or shorter than other basic continuous operations. Similarly, the duration D2 of each batch operation can be uniform or can be varied such that each operation is longer than, substantially equal to, or shorter than other batch operations. As described above, a scale inhibitor can be introduced at a predetermined time to introduce / initiate a second initiation period. Therefore, one or more batch operations may include a duration D2 that is longer than other batch operations that do not involve the use of a scale inhibitor to achieve the second initiation period.

[0097] As further shown, the filtration system 300 can operate at a 0% recovery rate, resulting in optional (complete) rinsing of at least one filter membrane 311, such that all received feed water is output as retentate. This optional rinsing can be triggered, for example, by a second drive signal, as described above regarding... Figure 5 The process described in 500 is as follows. However, optional rinsing may also be caused by a third drive signal. Preferably, the third drive signal is configured to result in a third target recovery rate, for example, 0% in the case of a full rinse, or greater than zero (0%) and less than or equal to the maximum non-fouling recovery rate (e.g., 80%) in the case of a partial rinse. In embodiments, the third target recovery rate may differ from the first target recovery rate and the second target recovery rate, as described above regarding... Figure 5 The process described in 500.

[0098] For example, as shown, within a third time period (or duration) D3 based on a third drive signal, the filtration system 300 can operate below the maximum non-fouling / fouling recovery rate, for example, between 1-80%, preferably at 80% recovery rate. Duration D3 is designed to result in at least partial flushing of at least one filter membrane 311 without requiring a complete flush (e.g., flushing at 0% recovery rate for a period of time). Therefore, the filtration system 300 can continue to generate permeate streams without intervening in a complete flush, meaning, for example, it does not need to be reduced to 0% recovery rate for flushing after batch RO operation.

[0099] Therefore, aspects of this disclosure enable NF / RO designers to select the optimal operating method for combining selected elements of continuous and batch NF / RO systems based on the constraints of the end-user facility, and to reduce long-term operating costs for the plant. This document also discloses a method for extending batch operation to a second initiation period by injecting an antiscalant, which allows for higher water recovery rates. Furthermore, in addition to scaling, the techniques and features disclosed herein can also be used for fouling management, as fouling similarly negatively impacts the pressure and recovery rates of NF / RO systems.

[0100] Other examples and structures

[0101] One aspect of this disclosure includes a method for determining recovery rate and power conditions / parameters (also referred to herein as operating parameters) that allow an NF / RO system to operate at a setpoint that, in a general sense, falls on a continuum between two extremes: non-scaling stable operation (with or without scale inhibitor) provided by a continuous system and batch operation with 100% recovery provided by an RO system. Therefore, the following disclosure provides the following non-limiting embodiments.

[0102] Implementation 1 includes operating an NF / RO system having at least one feed stream, one discharge stream, and one permeate stream, wherein for at least a portion of the operating cycle, the recovery rate is set between the extremes of a 100% recovery rate and a maximum non-fouling or non-contamination recovery rate.

[0103] Implementation 2 includes operating an NF / RO system having at least one feed stream, one discharge stream, and one permeate stream, wherein for at least a portion of the operating cycle, the recovery rate is set between an extreme value of 100% recovery rate and a maximum non-fouling or non-contamination recovery rate, and the feed flushing sequence is the final step of the operating cycle before repeating the operating cycle. (See, for example, [link to relevant documentation]). Figure 4 The order in B)

[0104] Implementation 3 includes a method for operating an NF / RO system having at least one feed stream, one discharge stream, and one permeate stream, wherein for a portion of the operating cycle, the recovery rate is set between a 100% recovery rate and an extreme value of a maximum non-fouling or non-contamination recovery rate, and for another portion of the operating cycle, the recovery rate is 100% (see, for example, see...). Figure 4 The order of A and C does not necessarily require a flushing cycle.

[0105] Implementation method 4 is a method for operating an NF / RO system having at least one feed stream, one discharge stream, and one permeate stream, wherein for a portion of the operating cycle, the recovery rate is set between a 100% recovery rate and an extreme value of a maximum non-fouling or non-contamination recovery rate, and for another portion of the operating cycle, the recovery rate is 100%, with the feed flushing sequence serving as the final step of the operating cycle before repeating the cycle. (See, for example...) Figure 4 (in the order A and C).

[0106] Implementation 5 is a method for operating an NF / RO system having at least one feed stream, one discharge stream, and one permeate stream, wherein for at least a portion of the operating cycle, the recovery rate is set between a 100% recovery rate and an extreme value of a maximum non-scaling or non-fouling recovery rate. During a first initiation period, no scale inhibitor is used initially until a predetermined time just before scaling / fouling occurs, at which point one or more doses of scale inhibitor are then added to the feed to extend the operation (e.g., a second initiation period) just before the feed flushing sequence, which is the final step of the operating cycle, is completed before repeating the operating cycle one or more times.

[0107] Implementation 6 is a method for operating an NF / RO system having at least one feed stream, one discharge stream, and one permeate stream, wherein for a portion of the operating cycle, the recovery rate is set between a 100% recovery rate and an extreme value of a maximum non-fouling or non-contamination recovery rate, and for another portion of the operating cycle, the recovery rate is 100%. During the first initiation period, no scale inhibitor is used at the beginning of the operation until just before reaching the scale inhibitor-free initiation period (or the second initiation period), and then a dose of scale inhibitor is added to the feed so that the operation (e.g., the second initiation period) can be extended until the scale inhibitor initiation period just before the operation cycle is completed with the feed flushing sequence as the last step of the operation cycle, before repeating the operation cycle.

[0108] Implementation 7 is a method for operating an NF / RO system having at least one feed stream and one permeate stream, wherein the recovery rate is 100%, and during the first initiation period, no scale inhibitor is used at the beginning of the operation until just before reaching the scale inhibitor-free initiation period (second initiation period), then the dosage of scale inhibitor is added to the feed so that the operation (second initiation period) can be extended just before the operation cycle is completed with the feed flushing sequence as the last step of the operation cycle before the operation cycle is repeated.

[0109] Implementation 8 is a method of operating an NF / RO system having at least one feed stream and one permeate stream, wherein the recovery rate is 100%, and scale inhibitors are used in operation so that, before repeated operating cycles, concentration is achieved beyond the scale-initiating period without scale inhibitors, until just before the scale-initiating period.

[0110] Implementation 9 is a method for operating an NF / RO system having a plate-and-frame or spacer-tube high-pressure membrane module, having at least one feed stream and one permeate stream, wherein the recovery rate is 100%, no scale inhibitor is used at the beginning of operation, and then the scale inhibitor is added to the feed just before reaching the scale inhibitor-free initiation period, so that the operation (second initiation period) can be extended to the scale inhibitor initiation period just before the feed flushing sequence is completed as the last step of the operation cycle before repeating the operation cycle.

[0111] Implementation 10 is a method of operating an NF / RO system having a plate-and-frame or spacer-tube high-pressure membrane module, having at least one feed stream and one permeate stream, wherein the recovery rate is 100%, and the system is operated with an antiscalant so that the concentration can be made beyond the antiscalant-free initiation period before repeated operating cycles are completed, until just before the antiscalant initiation period.

[0112] Implementation 11 is a method of operating a filtration system having at least one inlet fluidly coupled to at least one feed stream, at least one filter membrane fluidly coupled to said at least one inlet to receive feed water from said at least one feed stream, and at least one pump for generating pressure to transfer feed water from said at least one feed stream to said at least one filter membrane and generate an output permeate stream, the method comprising providing a first drive signal to said at least one pump such that the generated pressure generates an output permeate stream at a recovery rate substantially equal to a first target recovery rate within a first time period, said first target recovery rate being greater than a maximum non-fouling recovery rate of said at least one filter membrane and less than 100%.

[0113] Implementation 12 includes the features of implementation 11, and further includes providing a second drive signal to at least one pump such that the generated pressure produces an output permeate stream at a recovery rate substantially equal to the second target recovery rate during a second time period.

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

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

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

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

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

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

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

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

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

[0123] Implementation 22 includes the features of implementation 21, wherein the second target recovery rate is equal to 100%, and wherein causing at least one discharge valve to output a first predetermined portion of the feed water of at least one feed stream as truncation water during the second time period further includes closing at least one discharge valve so that at least one feed stream is output as truncation water at a basic 0%.

[0124] Implementation 23 includes the features of implementation 21, wherein the second target recovery rate is less than 100%, and wherein causing at least one discharge valve to output a first predetermined portion of at least one feed stream as truncation water during the second time period further includes opening at least one discharge valve to output the first predetermined portion of the feed water as wastewater.

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

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

[0127] Implementation 26 includes the features of implementation 12, wherein the second target recovery rate is 100%, and providing a second drive signal to at least one pump further includes introducing one or more antiscalant doses into at least one filter membrane at a predetermined time within a second time period, wherein the predetermined time period divides the second time period into a first initiation period occurring before the predetermined time period and a second initiation period occurring after the predetermined time period of antiscalant introduction, the first initiation period being the time period before scaling and / or fouling occurs in at least one filter membrane, and the second initiation period being the time period measured from the introduction of the antiscalant to the time when scaling and / or fouling occurs in at least one filter membrane.

[0128] Embodiment 27 includes the features of any one of embodiments 11-26, and further includes providing a third drive signal to at least one pump to at least partially flush at least one filter membrane, wherein providing the third drive signal to at least one pump to at least partially flush at least one filter membrane further includes providing the third drive signal to at least one pump during a third time period after the second time period.

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

[0130] Implementation 29 includes the features of implementation 28, wherein during a third time period, the third target recovery rate is between 0% and 80%, resulting in partial flushing of at least one filter membrane.

[0131] Implementation 30 includes the features of implementation 28, wherein the third target recovery rate is substantially 0% to result in the complete rinsing of 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.

[0132] Embodiment 31 includes the features of any one of embodiments 11-30, wherein the second time period is after the first time period, and wherein the second drive signal is provided during the second time period without causing interim complete flushing of at least one filter membrane between the first and second time periods.

[0133] Implementation 32 includes the features of implementation 12, wherein the second drive signal is configured to increase the pressure generated by at least one pump by an amount exceeding the osmotic pressure of at least one filter membrane, such that the pressure increases by at least 10 psi per minute during a second time period, the second time period being at least two (2) minutes.

[0134] Implementation 33 includes the features of implementation 12, wherein the second drive signal is configured to cause 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 during a second time period of at least 6 hours.

[0135] Implementation 34 includes the features of any one of Implementations 11-33, wherein the first drive signal is configured to increase the pressure generated by at least one pump by an amount exceeding the osmotic pressure of at least one filter membrane, such that the pressure increases by at least 10 psi per minute during a first time period, the first time period being at least two (2) minutes.

[0136] Implementation 35 includes the features of any one of Implementations 11-33, wherein the first drive signal is configured to cause at least one pump to generate a substantially constant pressure such that the substantially constant pressure increases by a maximum of 10 pounds per square inch (psi) per hour during a first time period of at least 6 hours.

[0137] Embodiment 36 includes the features of any one of embodiments 11-35, and further includes fluidly coupling at least one discharge valve to at least one filter membrane to output a second predetermined portion of the feed water of at least one feed stream as truncation water during a first time period.

[0138] Implementation 37 includes the features of implementation 36, wherein the first target recovery rate is less than or equal to 98%, and wherein causing at least one discharge valve to output a second predetermined portion of the feed water of at least one feed stream as truncation water during a first time period further includes opening at least one discharge valve such that at least 2% of the feed water of at least one feed stream is output as truncation water during the first time period.

[0139] Embodiment 38 includes the features of any one of embodiments 11-37, wherein providing the first drive signal to at least one pump further includes introducing one or more antiscalant doses into at least one filter membrane at a predetermined time during a first time period, the predetermined time being at the initial start of the first time period or after the initial start of the first time period and before scaling and / or fouling of at least one filter membrane.

[0140] Implementation 39 includes the features of implementation 38, wherein a predetermined time divides a first time period into a first initiation period occurring before the predetermined time and a second initiation period occurring after the predetermined time of introduction of the scale inhibitor, the first initiation period being the time period before scaling and / or fouling of at least one filter membrane occurs, and the second initiation period being the time period measured from the introduction of the scale inhibitor to the time when scaling and / or fouling of at least one filter membrane occurs.

[0141] Embodiment 40 includes the features of Embodiment 39, wherein providing the first drive signal to at least one pump further includes monotonically increasing the pressure of at least one pump beyond the osmotic pressure of at least one filter membrane from a predetermined moment when the antiscalant is introduced, in order to maintain the first target recovery rate for at least a portion of the second initiation period.

[0142] Embodiment 41 is a filtration system comprising at least one inlet fluidly coupled to at least one feed stream, at least one filter membrane fluidly coupled to said at least one inlet to receive feed water from the at least one feed stream, at least one pump for generating pressure to transfer feed water from the at least one feed stream to the at least one filter membrane and generate an output permeate stream, and a controller configured to provide a first drive signal to the at least one pump such that the generated pressure generates the output permeate stream at a recovery rate substantially equal to a first target recovery rate over a first time period, the first target recovery rate being greater than a maximum non-fouling recovery rate of the at least one filter membrane and less than 100%.

[0143] Implementation 42 includes the features of implementation 41, wherein the controller is further configured to provide a second drive signal to at least one pump such that the generated pressure produces an output permeate stream at a recovery rate substantially equal to the second target recovery rate during a second time period.

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

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

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

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

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

[0149] Implementation 48 includes the features of implementation 46, wherein the second target recovery rate is less than or equal to the maximum non-fouling recovery rate of at least one filter membrane during a portion of the second time period, and greater than the maximum non-fouling recovery rate during a portion of the second time period.

[0150] Implementation 49 includes the features of implementation 46, wherein the second target recovery rate is greater than 0% and less than the maximum non-fouling recovery rate, resulting in partial flushing of at least one filter membrane.

[0151] Implementation 50 includes the features of implementation 42, wherein the second target recovery rate is between 96 and 100%, such that the volume ratio of the feed water received to the output permeate stream during the second time period is between 0.96 and 1.0.

[0152] Embodiment 51 includes the features of Embodiment 42, and further includes at least one discharge valve fluidly coupled to at least one filter membrane to output a first predetermined portion of the feed water of at least one feed stream as truncation water during a second time period.

[0153] Implementation 52 includes the features of implementation 51, wherein the second target recovery rate is equal to 100%, and wherein the controller is configured to close at least one discharge valve so that a first predetermined portion of the feed water output as truncation water during a second time period is zero.

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

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

[0156] Implementation 55 includes the features of any one of Implementations 42-54, wherein the second drive signal is further configured to introduce one or more antiscalant doses into at least one filter membrane at a predetermined time during a second time period.

[0157] Implementation 56 includes the features of implementation 55, wherein a predetermined time divides the second time period into a first initiation period occurring before the predetermined time and a second initiation period occurring after the predetermined time of introduction of the scale inhibitor, the first initiation period being the time period before at least one filter membrane becomes scaled and / or fouled, and the second initiation period being the time period measured from the introduction of the scale inhibitor to the time when at least one filter membrane becomes scaled and / or fouled.

[0158] Implementation 57 includes the features of any one of Implementations 42-56, wherein the controller is further configured to provide a third drive signal to at least one pump to cause at least partial flushing during a third time period following the second time period.

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

[0160] Implementation 59 includes the features of any one of Implementations 57-58, wherein during the third time period, the third target recovery rate is between 0% and 80%, resulting in partial flushing of at least one filter membrane.

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

[0162] Embodiment 61 includes the features of any one of embodiments 42-60, wherein the second time period is after the first time period, and wherein the second drive signal is provided during the second time period without causing interim complete flushing of at least one filter membrane between the first and second time periods.

[0163] Implementation 62 includes the features of implementation 42, wherein the second drive signal is configured to increase the pressure generated by at least one pump by an amount exceeding the osmotic pressure of at least one filter membrane, such that the pressure increases by at least 10 psi per minute during a second time period, the second time period being at least two (2) minutes.

[0164] Implementation 63 includes the features of implementation 42, wherein the second drive signal is configured to cause 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 during a second time period of at least 6 hours.

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

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

[0167] Embodiment 66 includes the features of any one of embodiments 41-65, and further includes at least one discharge valve fluidly coupled to at least one filter membrane to output a second predetermined portion of the feed water of at least one feed stream as truncation water during a first time period.

[0168] Implementation 67 includes the features of implementation 66, wherein the first target recovery rate is less than or equal to 98%, the first predetermined portion of the feed water is at least 2%, and wherein the controller is configured to cause at least one discharge valve to output the first predetermined portion of the feed water of at least one feed stream as truncation water during a first time period.

[0169] Implementation 68 includes the features of any one of Implementations 41-67, wherein the controller is further configured to introduce one or more antiscalant doses into at least one filter membrane at a predetermined time during a first time period.

[0170] Implementation 69 includes the features of implementation 68, wherein a predetermined time divides a first time period into a first initiation period occurring before the predetermined time and a second initiation period occurring after the predetermined time of introduction of the scale inhibitor, the first initiation period being the time period before at least one filter membrane becomes scaled and / or fouled, and the second initiation period being the time period measured from the introduction of the scale inhibitor to the time when at least one filter membrane becomes scaled and / or fouled.

[0171] Implementation 70 includes the features of implementation 69, wherein providing the first drive signal to at least one pump further includes monotonically increasing the pressure of at least one pump beyond the osmotic pressure of at least one filter membrane from a predetermined moment when the antiscalant is added, in order to maintain the first target recovery rate for at least a portion of the second initiation period.

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

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

[0174] Embodiment 73 includes the features of Embodiment 72, and further includes a filter valve arrangement for switchably fluidly coupling the first filter membrane and / or the second filter membrane to at least one feed flow.

[0175] Implementation 74 includes the features of implementation 73, wherein the controller is further configured to allow the filter valve to switchably fluidly couple the first filter membrane and / or the second filter membrane to at least one feed flow during a first time period and / or a second time period.

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

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

[0178] Implementation 77 is a method for operating a filtration system having at least one filter membrane fluidly coupled to at least one feed stream inlet, at least one filter membrane fluidly coupled to the inlet to receive feed water from at least one feed stream, and at least one pump for generating pressure to transfer feed water from at least one feed stream to at least one filter membrane and generate an output permeate stream. The method includes providing a first drive signal to at least one pump, wherein the first drive signal increases the pressure generated by at least one pump by an amount exceeding the osmotic pressure of at least one filter membrane and maintains a target recovery rate for a first time period exceeding a maximum non-fouling recovery rate and having an associated duration before reaching the maximum non-fouling recovery rate state of at least one filter membrane; detecting when the maximum non-fouling recovery rate state of at least one filter membrane is reached within the first time period; and in response to detecting that the maximum non-fouling recovery rate state has been reached, introducing one or more antiscalant doses into at least one filter membrane to increase the amount of time between reaching the maximum non-fouling recovery rate state and when scaling and / or fouling of at least one filter membrane occurs.

[0179] Embodiment 78 is a method for 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 to receive feed water from at least one feed stream, and at least one pump for generating pressure to transfer the feed water from at least one feed stream to at least one filter membrane and generate an output permeate stream. The method includes providing a first drive signal to at least one pump to cause the output of the output permeate stream substantially at a target recovery rate greater than the maximum non-fouling recovery rate of at least one filter membrane within a first time period, and the first drive signal increasing the pressure generated by at least one pump by an amount exceeding the osmotic pressure of at least one filter membrane to maintain the output of the output permeate stream substantially at the target recovery rate, and introducing one or more antiscalant doses into at least one filter membrane at predetermined times within the first time period.

[0180] Implementation 79 includes the features of Implementation 78, wherein a predetermined time divides a first time period into a first initiation period occurring before the predetermined time and a second initiation period occurring after the predetermined time when one or more antiscalant doses are introduced, the first initiation period being the time period before scaling and / or fouling occurs, and the second initiation period being the time period measured from the introduction of one or more antiscalant doses to the occurrence of scaling and / or fouling.

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

[0182] Implementation 82 is a non-transitory computer-readable medium having a plurality of instructions stored thereon, which cause the method according to any one of Implementations 1-40 to be executed.

[0183] While the principles of this disclosure have been described herein, those skilled in the art will understand that this description is by way of example only and is not intended to limit the scope of this disclosure. Other embodiments are contemplated within the scope of this disclosure in addition to the exemplary embodiments shown and described herein. Those skilled in the art will understand that surface cleaning devices may embody any one or more features contained herein, and that these features may be used in any particular combination or sub-combination. Modifications and substitutions by those skilled in the art are considered to fall within the scope of this disclosure and, apart from the claims, do not limit the scope of this disclosure.

Claims

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

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

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

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

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

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

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

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

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

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

0.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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