Water purification systems and methods

Abstract

A water purification system comprising: a filter having an input port and an output port, the inlet port fluidically coupled to an influent inlet; a first hydraulic cylinder; a hydraulic actuator; a hydraulic coupler fluidically coupled to the hydraulic actuator; and a piston, the piston having a first piston plate disposed in the first hydraulic cylinder; a second piston plate disposed in the hydraulic coupler; and a piston rod mechanically coupled between the first piston plate and the second piston plate.

Description

WATER PURIFICATION SYSTEMS AND METHODSBACKGROUNDField of Invention

[0001] The invention relates generally the field of water purification. As used herein, water purification includes desalination and reclamation applications. More particularly, but not by way of limitation, embodiments of the invention provide systems and methods for improving the efficiency of systems and methods that utilize reverse osmosis (RO) membranes or similar components.Description of the Related Art

[0002] Clean freshwater is a vital resource that is used for human consumption (e.g., in drinking water or prepared food), plant irrigation, certain industrial processes, and other applications. Yet clean freshwater is extremely limited, since the vast majority of water on earth is saltwater, and because both freshwater and saltwater sources are increasingly contaminated. Such contamination includes, for example, human waste, animal waste, manufacturing byproducts, microplastics, nanoplastics, other forms of human-generated pollution and / or natural impurities.

[0003] Many known systems and methods for water purification use reverse osmosis (RO) membranes to separate water molecules from other substances. In conventional operation, un-purified water (influent) is applied to one side of the RO membrane under positive pressure, and purified water (permeate) passes to the unpressurized side of the RO membrane. RO membranes require periodic maintenance due to fouling; this can be accomplished via forward or backward flushing. Backflushing (or backwashing) refers to pumping clean water (backflush) in a reverse direction through the RO membrane (7.e. , in a direction opposite to purification flow).

[0004] Conventional RO systems and methods have various shortcomings. For instance, throughput (volume of purified water generated per unit of time) is extremely limited and / or the energy consumption (e.g., as measured in kWh)required to pressurize such systems is impractically high for the required throughput of purified water. Improved water purification systems and methods that can operate with better energy efficiently are urgently needed.SUMMARY OF THE INVENTION

[0005] Embodiments of the invention are directed to water purification systems and methods for using such systems. Alternative embodiments, and their advantages, will be described below with reference to FIGS. 1-52.BRIEF DESCRIPTION OF THE DRAWINGS

[0006] FIGS. 1-12 are system diagrams according to a first embodiment of the invention, illustrating an exemplary water purification process.

[0007] FIGS. 13-25 are system diagrams according to the first embodiment of the invention, illustrating an exemplary backflush process.

[0008] FIGS. 26-37 are system diagrams according to a second embodiment of the invention, illustrating an exemplary water purification process.

[0009] FIGS. 38-50 are system diagrams according to the second embodiment of the invention, illustrating an exemplary backflush process.

[0010] FIG. 51 is a system diagram for a variant of the second embodiment of the invention.

[0011] FIG. 52 is a system diagram for an exemplary hydraulic actuator for use with the first and second embodiments of the invention.DETAILED DESCRIPTION

[0012] The following description of each embodiment is meant to be illustrative and not restrictive. Certain conventional features may be omitted from the drawings forclarity. Textual subheadings are used for organizational convenience; the description of any claimed feature is not necessarily restricted to the description of any particular embodiment. As used herein, “negative pressure” is a relative term, e.g. less than atmospheric or ambient pressure, sufficient to cause a desired pressure gradient. Likewise, “positive pressure” is also a relative term, e.g. greater than atmospheric or ambient pressure, sufficient to cause a desired pressure gradient. As used herein, “fluidically coupled” refers to a fluid path between system features, even if such fluid path is controlled by one or more valves, as described below. We begin by disclosing a first embodiment of the invention.First Embodiment

[0013] FIGS. 1-25 are system diagrams according to a first embodiment of the invention. As shown therein, a water purification system 100 includes a hydraulic cylinder 101 fluidically coupled to a first output port of a reverse osmosis (RO) membrane 106. As used herein, the RO membrane 106 can be a higher level of assembly, i.e. , a filter that includes an RO membrane as a component.

[0014] A piston 102 extends between the hydraulic cylinder 101 and a hydraulic coupler 105. The piston 102 includes a piston plate 103, a piston plate 308, and a piston rod 124. The piston plate 103 is disposed in the hydraulic cylinder 101 and preferably includes a seal ring (not illustrated) to cooperate with interior walls of the hydraulic cylinder 101. The piston plate 308 is disposed in the hydraulic coupler 105 as best illustrated in FIG. 52. The piston plate 103 is mechanically coupled to a first end of the piston rod 124. The piston plate 308 is mechanically coupled to a second end of the piston rod 124. In operation, the hydraulic actuator 104 moves the piston 102 by applying a force to the piston plate 308. No fluid flows between the hydraulic cylinder 102 and the hydraulic coupler 105.

[0015] In the illustrated embodiment, influent filters 107 and 108 are fludically coupled, in series, between an influent inlet 109 and an input port of the RO membrane 106.

[0016] FIGS. 1-25 show multiple valves 115-123. Valves 115 and 116 are each fluidically coupled to a corresponding port at a first end of the hydraulic cylinder 101. Valves 119 and 120 are each fluidically coupled to a corresponding port at a second end of the hydraulic cylinder 101. Valves 115 and 119 are each fluidically coupled between the hydraulic cylinder 101 and a first output port of the RO membrane 106. Valve 117 is fluidically coupled between valve 116 and backflush inlet 110. Valve 118 is fluidically coupled between valve 116 and permeate outlet 111. Valve 121 is fluidically coupled between valve 120 and permeate outlet 112. Valve 122 is fluidically coupled between valve 120 and backflush inlet 113. Valve 123 is fluidically coupled between a second output port of the RO membrane 106 and a reject discharge 114. In the drawings, open valves are rendered with no fill, and closed valves are rendered with black fill.

[0017] Variations to the system configuration illustrated in FIGS. 1-25 are possible. For example, graphene or other filtration devices could be used instead of the RO membrane 106. In alternative embodiments, influent filter 107 and / or influent filter 108 may be excluded, according to application requirements. The type of valve selected for each valve 115-123 could vary according to design choice. For instance, one or more such valves could be a gate valve, a ball valve, a butterfly valve, a solenoid valve, or a control valve. Where operation is limited to a single direction of flow (for instance in the case of valves 117, 118, 121 , 122, and 123) a check valve could be used. Moreover, one or more multi-port valves could be used, for example a multiport valve could be used in place of valves 117 and 118, or a multiport valve could be used in place of valves 116, 117, and 118, to provide an equivalent system configuration.

[0018] FIGS. 1-12 illustrate a water purification method using the system 100. FIGS. 1-12 are sequential “snapshots” of a dynamic process involving small batches of fluid. FIG. 1 can be considered an initial state, with all valves being closed. FIG. 2 illustrates opening valves 115, 120, and 121. FIG. 3 illustrates retracting the piston 102 in a direction 127. The piston plate 103 divides an interior of the hydraulic cylinder 101 into chambers 125 and 126. The chamber 125 is fluidically coupled to the ports at the first end of the hydraulic cylinder 101 ; the chamber 126 is fluidically coupled to the ports at the second end of the hydraulic cylinder 101. Retraction ofthe piston 102 creates a negative pressure in the chamber 125. Since valve 115 is open, such negative pressure causes influent to be drawn from the influent inlet 109, through influent filters 108 and 107, and through RO membrane 106. Permeate (purified water) is drawn from the first output port of the RO membrane 106 into the chamber 125. Open valves 120 and 121 permit any air that is trapped in chamber 126 to escape. FIG. 4 illustrates the piston 102 being fully retracted. FIG. 5 illustrates closing valves 115, 120, and 121. Preferably, chamber 125 is filled with permeate at this step of the water purification process.

[0019] FIG. 6 illustrates opening valves 116, 118, and 119. FIG. 7 illustrates extending the piston 102 in a direction 128. Such extension creates a positive pressure in the chamber 125, and a negative pressure in the chamber 126. Accordingly, the permeate is discharged from the chamber 125 to the permeate outlet 111. Simultaneously, additional influent is drawn from the influent inlet 109, through influent filters 108 and 107, through RO membrane 106, and into the chamber 126. FIG. 8 illustrates the piston 102 being fully extended. FIG. 9 illustrates closing the valves 116, 118, and 119. Preferably, chamber 126 is filled with permeate at this step of the water purification process.

[0020] FIG. 10 illustrates opening valves 115, 120, and 121. FIG. 11 illustrates retracting the piston 102 in the direction 127. Such retraction creates a positive pressure in the chamber 126, and a negative pressure in the chamber 125. Accordingly, the permeate is discharged from the chamber 126 to the permeate outlet 112. Simultaneously, additional influent is drawn from the influent inlet 109, through influent filters 108 and 107, through RO membrane 106, and into the chamber 125. FIG. 12 illustrates the piston 102 being fully retracted.

[0021] FIGS. 13-25 illustrate a backflush method using the system 100. FIGS. 13-25 are sequential “snapshots” of a dynamic process involving small batches of fluid. FIG. 13 can be considered an initial state, with all valves being closed. FIG. 14 illustrates opening valves 116, 118, 120 and 122. FIG. 15 illustrates extending the piston 102 in a direction 128. Such extension creates a negative pressure in chamber 126. Since valves 120 and 122 are open, such negative pressure causes backflush fluid to be drawn from backflush inlet 113 into the chamber 126. Openvalves 116 and 118 permit any air that is trapped in chamber 125 to escape. FIG. 16 illustrates the piston 102 being fully extended. FIG. 17 illustrates closing the valves 116, 118, 120 and 122. Preferably, chamber 126 is filled with backflush fluid at this step of the process.

[0022] FIG. 18 illustrates opening valves 116, 117 and 119. FIG. 19 illustrates retracting the piston 102 in the direction 127. Such retraction creates a positive pressure in the chamber 126, and a negative pressure in the chamber 125. Accordingly, the backflush fluid is forced from the chamber 126 to the first outlet port of the RO membrane 106, and through the RO membrane 106 and influent filters 107, 108 in a reverse direction. Simultaneously, additional backflush fluid is drawn from the backflush inlet 110 into the chamber 125. FIG. 20 illustrates the piston 102 being fully retracted. FIG. 21 illustrates closing the valves 116, 117, and 119. Preferably, chamber 125 is filled with backflush fluid at this step of the process.

[0023] FIG. 22 illustrates opening valve 115. FIG. 23 illustrates extending the piston 102 in the direction 128. Such extension creates a positive pressure in the chamber 125. Accordingly, the backflush fluid is forced from the chamber 125 to the first outlet port of the RO membrane 106 in a backward direction. Contaminated backflush flows in a backward direction through the influent filters 107, 108 for discharge at the influent inlet 109. As an alternative to the embodiments illustrated in FIGS. 19 and 23, contaminated backflush could instead be discharged from another input port (not shown) of the RO membrane 106. FIG. 24 illustrates the piston 102 being fully extended. FIG. 25 illustrates closing the valve 115.

[0024] The first system embodiment and related methods offer several distinct advantages over prior art systems and methods. For instance, with respect to water purification, the system 100 is configured to draw fluid through the RO membrane 106 due to negative pressure generated in the chambers 125, 126. Empirical evidence suggests this is more energy efficient than using positive pressure to force influent through the RO membrane to produce permeate. In addition, after an initial priming cycle (FIGS. 2-4), the system 100 is configured to simultaneously filter influent through the RO membrane 106 and discharge permeate; this occurs when the piston 102 is extending (FIGS. 6-8) and also when the piston 102 is retracting(FIGS. 10-12) for a virtual continuous duty cycle. Likewise, after an initial priming cycle (FIGS. 14-16), the system 100 is configured to perform backflush when the piston 102 is retracting (FIGS. 18-20) and also when the piston 102 is extending (FIGS. 22-24).Second Embodiment

[0025] FIGS. 26-50 are system diagrams according to a second embodiment of the invention. As shown therein, a water purification system 200 includes a hydraulic cylinder 201 fluidically coupled to an input port and a first output port of a reverse osmosis (RO) membrane 206. As used herein, the RO membrane 206 can be a higher level of assembly, i.e., a filter that includes an RO membrane as a component.

[0026] A piston 202 extends between the hydraulic cylinder 201 and a hydraulic coupler 205. The piston 202 includes a piston plate 203, a piston plate 308, and a piston rod 221 . The piston plate 203 is disposed in the hydraulic cylinder 201 and preferably includes a seal ring (not illustrated) to cooperate with interior walls of the hydraulic cylinder 201. The piston plate 308 is disposed in the hydraulic coupler 205 as best illustrated in FIG. 52. The piston plate 203 is mechanically coupled to a first end of the piston rod 221 . The piston plate 308 is mechanically coupled to a second end of the piston rod 221. In operation, the hydraulic actuator 204 moves the piston 202 by applying a force to the piston plate 308. No fluid flows between the hydraulic cylinder 202 and the hydraulic coupler 205.

[0027] FIGS. 26-50 illustrates multiple valves 212-220 as part of the system 200. Valves 212 and 213 are each fluidically coupled to a corresponding port at a first end of the hydraulic cylinder 201. Valves 216 and 217 are each fluidically coupled to a corresponding port at a second end of the hydraulic cylinder 201. Valve 212 is fluidically coupled between the hydraulic cylinder 201 and the input port of the RO membrane 206; and valve 216 is fluidically coupled between the hydraulic cylinder 201 and a first output port of the RO membrane 206. Valve 214 is fluidically coupled between valve 213 and backflush outlet 207. Valve 215 is fluidically coupled between valve 213 and influent inlet 208. Valve 218 is fluidically coupled betweenvalve 217 and permeate outlet 209. Valve 219 is fluidically coupled between valve 217 and backflush inlet 210. Valve 220 is fluidically coupled between a second output port of the RO membrane 206 and a reject discharge 211. In the drawings, open valves are rendered with no fill, and closed valves are rendered with black fill.

[0028] Variations to the system configuration illustrated in FIGS. 26-50 are possible. For example, graphene or other filtration devices could be used instead of the RO membrane 206. The type of valve selected for each valve 212-220 could vary according to design choice. For instance, one or more such valves could be a gate valve, a ball valve, a butterfly valve, a solenoid valve, or a control valve. Where operation is limited to a single direction of flow (for instance in the case of valves 214, 215, 218, 219 and 220) a check valve could be used. Moreover, one or more multi-port valves could be used, for example a multiport valve could be used in place of valves 214 and 215, or a multiport valve could be used in place of valves 213,214, and 215, to provide an equivalent system configuration.

[0029] FIGS. 26-33 illustrate a water purification method using the system 200. FIGS. 26-33 are sequential “snapshots” of a dynamic process involving small batches of fluid. FIG. 26 can be considered an initial state, with all valves being closed. FIG. 27 illustrates opening valves 213, 215, 217 and 218. FIG. 28 illustrates retracting the piston 202 in a direction 224. The piston plate 203 divides an interior of the hydraulic cylinder 201 into chambers 222 and 223. The chamber 222 is fluidically coupled to the ports at the first end of the hydraulic cylinder 201 ; the chamber 223 is fluidically coupled to the ports at the second end of the hydraulic cylinder 201. Retraction of the piston 202 creates a negative pressure in the chamber 222. Since valves 213 and 215 are open, such negative pressure causes influent to be drawn from the influent inlet 208 and into the chamber 222. Open valves 217 and 218 permit any air that is trapped in chamber 223 to escape. FIG. 29 illustrates the piston 202 being fully retracted. FIG. 30 illustrates closing valves 213,215, 217 and 218. Preferably, chamber 222 is filled with influent at this step of the water purification process.

[0030] FIG. 31 illustrates opening valves 212 and 216. FIG. 32 illustrates extending the piston 202 in a direction 225. Such extension creates a positive pressure in thechamber 222 and a negative pressure in the chamber 223. Accordingly, influent flows from the chamber 222 into the RO membrane 206. Simultaneously, permeate flows from the first output port of the RO membrane 206 into the chamber 223. Advantageously, the forward direction fluid flow just described (and illustrated in FIG. 32) through the RO membrane 206 is motivated by positive pressure in the chamber 222 and by negative pressure in the chamber 223. FIG. 33 illustrates the piston 202 being fully extended. FIG. 34 illustrates closing the valves 212 and 216. Preferably, chamber 223 is filled with permeate at this step of the water purification process.

[0031] FIG. 35 illustrates opening valves 213, 215, 217, and 218. FIG. 36 illustrates retracting the piston 202 in the direction 224. Such retraction creates a positive pressure in the chamber 223, and a negative pressure in the chamber 222. Accordingly, the permeate is discharged from the chamber 223 to the permeate outlet 209. Simultaneously, additional influent is drawn from the influent inlet 208 into the chamber 222. FIG. 37 illustrates the piston 202 being fully retracted.

[0032] FIGS. 38-50 illustrate a backflush method using the system 200. FIGS. 38-50 are sequential “snapshots” of a dynamic process involving small batches of fluid. FIG. 38 can be considered an initial state, with all valves being closed. FIG. 39 illustrates opening valves 213, 214, 217 and 219. FIG. 40 illustrates extending the piston 202 in a direction 225. Such extension creates a negative pressure in chamber 223. Since valves 217 and 219 are open, such negative pressure causes backflush fluid to be drawn from backflush inlet 210 into the chamber 223. Open valves 213 and 214 permit any air that is trapped in chamber 222 to escape. FIG. 41 illustrates the piston 202 being fully extended. FIG. 42 illustrates closing the valves 213, 214, 217 and 219. Preferably, chamber 223 is filled with backflush fluid at this step of the process.

[0033] FIG. 43 illustrates opening valves 212 and 216. FIG. 44 illustrates retracting the piston 202 in the direction 224. Such retraction creates a positive pressure in the chamber 223, and a negative pressure in the chamber 222. Accordingly, the backflush fluid is forced from the chamber 223 to the first outlet port of the RO membrane 206. Simultaneously, contaminated backflush fluid is drawn from the inlet port of the RO membrane 206 into the chamber 222. Advantageously, the reversedirection fluid flow just described (and illustrated in FIG. 44) through the RO membrane 206 is motivated by positive pressure in the chamber 223 and by negative pressure in the chamber 222. FIG. 45 illustrates the piston 202 being fully retracted. FIG. 46 illustrates closing the valves 212 and 216. Preferably, chamber 222 is filled with contaminated backflush fluid at this step of the process.

[0034] FIG. 47 illustrates opening valves 213 and 214. FIG. 48 illustrates extending the piston 202 in the direction 225. Such extension creates a positive pressure in the chamber 222. Accordingly, the contaminated backflush fluid is forced from the chamber 222 to the backflush outlet 207. FIG. 49 illustrates the piston 202 being fully extended. FIG. 50 illustrates closing the valves 213 and 214.

[0035] FIG. 51 is a system diagram for a variant of the second embodiment of the invention. In particular, FIG. 51 shows the addition of influent filters 226, 227 fluidically coupled in series between the influent inlet 208 and the valve 215. The type and number of influent filters could be varied according to application needs.

[0036] The second system embodiment and related methods offer distinct advantages over prior art systems and methods. For instance, with respect to both water purification and backflush processes, the system 200 is configured to simultaneously use both positive and negative pressure to motivate fluid flow through the RO membrane 206. Empirical evidence suggests this is more energy efficient than using positive pressure alone.Hydraulic Actuator

[0037] Water purification systems can require a significant amount of energy to move fluid through an RO membrane. For instance, 60% to 80% of Specific Energy Consumption (SEC) may be used to push fluid through the RO membrane, exclusive of Energy Recovery Devices (ERD). The hydraulic actuator 104, 204 presented in FIG. 52 is preferably used to reduce the SEC of water purification systems 100, 200.

[0038] As illustrated in FIG. 52, a pump & motor assembly 306 is disposed in a tank 307 and is fluidically coupled in parallel to a hydraulic cylinder 301. A primary pistonplate 302 disposed in the hydraulic cylinder 301 is configured to move on an axial shaft 303, the primary piston plate 302 separating an interior of the hydraulic cylinder 301 into chambers 304 and 305. Chamber 304 is fluidically coupled to the hydraulic coupler 105, 205. Secondary piston plate 308 is disposed in the hydraulic coupler 105, 205 at the second end of the piston rod 124, 221.

[0039] In operation, the pump & motor assembly 306 draws fluid from the tank 307 to apply hydraulic pressure. For instance, with reference to the first embodiment, to extend the piston 102 into the hydraulic cylinder 101 in direction 128, the pump & motor assembly 306 draws fluid from tank 307 to apply positive pressure to the chamber 305. This exerts a force on the primary pressure plate 302, causes a positive pressure in the hydraulic coupler 105, and exerts a force on the secondary pressure plate 308. To retract the piston 102 from the hydraulic cylinder 101 in direction 127, the pump & motor assembly 306 draws fluid from the tank 307 to apply a positive pressure to the hydraulic coupler 105. This exerts a force on the secondary pressure plate 308, and causes a positive pressure in the chamber 304.

[0040] The table below illustrates benefits of the configuration disclosed in Fig. 52. In each example presented in the table, the secondary piston plate 308 has a diameter of 6 inches, a target force on the secondary piston plate 308 is 28,953 lbs., and a target water purification throughput is 1 ,000 gpm (gallons per minute). As the diameter of the primary piston plate 302 increases, the required pressure from the pump & motor assembly 306 decreases, and thus energy consumption of the pump & motor assembly 306 also decreases.CONCLUSION

[0041] Accordingly, embodiments of the invention improve the efficiencies of water purification and similar systems by utilizing negative pressure to draw fluid through an RO membrane or similar filtration component. Preferred embodiments employ a hydraulic actuator with a force multiplier feature to further reduce the energy consumption of such systems. In embodiments of the invention, negative pressure and force multiplier features can be used separately or combined.

[0042] Those skilled in the art can readily recognize that numerous variations and substitutions may be made in the invention, its use and its configuration to achieve substantially the same results as achieved by the embodiments described herein. Accordingly, there is no intention to limit the invention to the disclosed exemplary forms. Many variations, modifications and alternative constructions fall within the scope and spirit of the disclosed invention.REFERENCE DESIGNATORS

[0043] The following list of reference designators used in this specification is provided for convenience.100 water purification system101 hydraulic cylinder102 piston103 piston plate104 hydraulic actuator105 hydraulic coupler106 reverse osmosis (RO) membrane107 influent filter108 influent filter109 influent inlet110 backflush inlet111 permeate outlet112 permeate outlet113 backflush inlet114 reject discharge [brine discharge, in the case of desalination]115 valve116 valve117 valve118 valve119 valvevalve valve valve valve piston rod chamber chamber direction of piston contraction direction of piston extension water purification system hydraulic cylinder piston piston plate hydraulic actuator hydraulic coupler reverse osmosis (RO) membrane backflush outlet influent inlet permeate outlet backflush inlet reject discharge valve valve valve valve valve valve valve valve valve piston rod chamber chamber direction of piston contraction direction of piston extension influent filter influent filter hydraulic cylinder piston plate shaft chamber chamber pump & motor assembly tank piston plate

Claims

CLAIMSI claim:1 . A water purification system comprising: a filter having an input port and an output port, the inlet port fluidical ly coupled to an influent inlet; a first hydraulic cylinder; a hydraulic actuator; a hydraulic coupler fluid ically coupled to the hydraulic actuator; and a piston, the piston having a first piston plate disposed in the first hydraulic cylinder; a second piston plate disposed in the hydraulic coupler; and a piston rod mechanically coupled between the first piston plate and the second piston plate, the first piston plate separating a first chamber from a second chamber in the first hydraulic cylinder, the first hydraulic cylinder having a first port and a second port coupled to the first chamber, the first hydraulic cylinder having a third port and a fourth port coupled to the second chamber, the first port and the third port flu idical ly coupled to the output port of the filter, the second port fluidically coupled to a first permeate outlet, the fourth port fluidically coupled to a second permeate outlet.

2. The water purification system of claim 1 , wherein the filter includes a reverse osmosis (RO) membrane.

3. The water purification system of claim 1 , further comprising at least one influent filter fluidically coupled between the influent inlet and the input port of the filter.

4. The water purification system of claim 1 , wherein the hydraulic actuator includes: a second hydraulic cylinder; a pump assembly; a third piston plate disposed in the second hydraulic cylinder; and an axial shaft disposed in the second hydraulic cylinder, the third piston plate configured to move along the axial shaft, the third piston plate separating a third chamber from a fourth chamber in the second hydraulic cylinder, the second hydraulic cylinder having a fifth port coupled to the third chamber, the second hydraulic cylinder having a sixth port coupled to the fourth chamber, the pump assembly having a seventh port and an eight port, the fifth port and the seventh port flu idical ly coupled to the hydraulic coupler, the sixth port flu idical ly coupled to the eight port.

5. A method for using the water purification system of claim 1 , the method comprising the following sequential steps: a) moving the piston in a first direction to create a negative pressure in the first chamber to draw a first batch of influent from the influent inlet into the input port of the filter and draw a first batch of permeate from the output port of the filter into the first chamber; b) moving the piston in a second direction to create a positive pressure in the first chamber to discharge the first batch of permeate from the first chamber to the first permeate outlet, and to simultaneously create a negative pressure in the second chamber to draw a second batch of influent from the influent inlet into the input port of the filter and draw a second batch of permeate from the output port of the filter into the first chamber; and c) moving the piston in the first direction to create a positive pressure in the second chamber to discharge the second batch of permeate from the second chamber to a second permeate outlet, and to simultaneously create a negative pressure in the first chamber to draw a third batch of influent from the influent inlet into the input port of the filter and draw a third batch of permeate from the output port of the filter into the first chamber.

6. The water purification system of claim 1 , further comprising: a first backflush inlet fluidical ly coupled to the fourth port; and a second backflush inlet fluid ically coupled to the second port.

7. A method for using the water purification system of claim 6, the method comprising the following sequential steps: a) moving the piston in a first direction to create a negative pressure in the second chamber to draw a first batch of backflush from the first backflush inlet into the the second chamber; b) moving the piston in a second direction to create a positive pressure in the second chamber and discharge the first batch of backflush from the second chamber to the output port of the filter, and to simultaneously create a negative pressure in the first chamber to draw a second batch of backflush from the second backflush inlet into the first chamber; and c) moving the piston in the first direction to create a positive pressure in the first chamber and discharge the second batch of backflush from the first chamber to the output port of the filter.

8. A water purification system comprising: a filter having an input port and an output port; a first hydraulic cylinder; a hydraulic actuator; a hydraulic coupler fluid ically coupled to the hydraulic actuator; and a piston, the piston having a first piston plate disposed in the first hydraulic cylinder; a second piston plate disposed in the hydraulic coupler; and a piston rod mechanically coupled between the first piston plate and the second piston plate, the first piston plate separating a first chamber from a second chamber in the first hydraulic cylinder, the first hydraulic cylinder having a first port and a second port coupled to the first chamber, the first hydraulic cylinder having a third port and a fourth port coupled to the second chamber, the first port flu idical ly coupled to an input port of the filter, the second port flu idical ly coupled to an influent inlet, the third port flu idical ly coupled to the output port of the filter, the fourth port flu idical ly coupled to a permeate outlet.

9. The water purification system of claim 8, wherein the filter includes a reverse osmosis (RO) membrane.

10. The water purification system of claim 8, further comprising at least one influent filter fluidically coupled between the influent inlet and the second port.11 . The water purification system of claim 8, wherein the hydraulic actuator includes: a second hydraulic cylinder; a pump assembly; a third piston plate disposed in the second hydraulic cylinder; and an axial shaft disposed in the second hydraulic cylinder, the third piston plate configured to move along the axial shaft, the third piston plate separating a third chamber from a fourth chamber in the second hydraulic cylinder, the second hydraulic cylinder having a fifth port coupled to the third chamber, the second hydraulic cylinder having a sixth port coupled to the fourth chamber, the pump assembly having a seventh port and an eight port, the fifth port and the seventh port fluidically coupled to the hydraulic coupler, the sixth port fluidically coupled to the eight port.

12. A method for using the water purification system of claim 8, the method comprising the following sequential steps: a) moving the piston in a first direction to create a negative pressure in the first chamber to draw a first batch of influent from the influent inlet into the first chamber; b) moving the piston in a second direction to create a positive pressure in the first chamber to discharge the first batch of influent into the input port of the filter, and simultaneously create a negative pressure in the second chamber to draw a first batch of permeate from the output port of the filter into the second chamber; and c) moving the piston in the first direction to create a positive pressure in the second chamber to discharge the first batch of permeate from the second chamber to the permeate outlet, and to simultaneously create a negative pressure in the first chamber to draw a third batch of influent from the influent inlet into the first chamber.

13. The water purification system of claim 8, further comprising: a backflush inlet flu idical ly coupled to the fourth port; and a backflush outlet flu idical ly coupled to the second port.

14. A method for using the water purification system of claim 13, the method comprising the following sequential steps: a) moving the piston in a first direction to create a negative pressure in the second chamber to draw a batch of backflush from the first backflush inlet into the the second chamber; b) moving the piston in a second direction to create a positive pressure in the second chamber and discharge the batch of backflush from the second chamber to the output port of the filter, and to simultaneously create a negative pressure in the first chamber to draw a batch of contaminated backflush from the input port of the filter into the first chamber; and c) moving the piston in the first direction to create a positive pressure in the first chamber and discharge the batch of contaminated backflush from the first chamber to the backflush outlet.

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