I claim:
1. A method for pressure-driven liquid separation, the method comprising:
a. receiving, by a sweep reverse osmosis (SRO) system, a system level feed solution to a
feed side of the SRO system and a system level sweep solution to a sweep side of the
SRO system;
b. receiving, by the semi-permeable membrane, a pass level feed solution from the system
level feed solution to a first side of the semi-permeable membrane, wherein the pass
level feed solution has a first osmotic pressure;
c. receiving, by the semi-permeable membrane, a pass level sweep solution from the
system level sweep solution to a second side of the semi-permeable membrane, wherein
the pass level sweep solution has a second osmotic pressure;
d. exerting, by a pressurizing unit, a pressure on the pass level feed solution on first side of
the semipermeable membrane such that, a permeate solution from the pass level feed
solution passes from the first side of the semipermeable membrane to the second side of
the semipermeable membrane, wherein the permeate solution has a different osmotic
pressure than the pass level and feed level solution, wherein the pressurizing unit
includes at l east one of an ener g y r eco v er y d e v i ce (E RD) , a h i gh pressure pump, a
booster pump, a piston, an hydraulic fluid and pneumatic fluid;
e. discharging, by the semipermeable membrane, a pass level concentrate solution from the
first side of the semi-permeable membrane, on passing the permeate solution to the
second side of the semipermeable membrane, wherein the discharged pass level
concentrate solution acts as the pass level feed solution to any subsequent pass until a
system level concentrate solution is generated;
f. discharging, by the semipermeable membrane, a pass level diluate solution from the
second side of the semi-permeable membrane, on receiving the permeate solution from
the first side of the semi permeable membrane, wherein the discharged pass level diluate
solution acts as the pass level sweep solution to any subsequent pass until a system level
diluate solution is generated;

g. removing, by the SRO system, the system level concentrate solution and the system level
diluate solution; and h. repeating by the SRO system steps (a-g) to continue with subsequent operation cycles.
2. The method as claimed in claim 1, wherein the feed side solution flows across the first side of the semipermeable membrane and the sweep side solution flows across the s eco n d side of t h e semip ermeable membr ane s u ch that the y are counte r cu rr en t , co-current or cross-current to each other.
3. The method as claimed in claim 1, wherein an energy recovery device(s) recovers energy exerted by the pressurizing unit.
4. The method as claimed in claim 1, wherein the method further comprises a circulation loop of the feed side solution flow and a circulation loop of the sweep side solution flow are hydraulically connected to transfer at least one of the feed side solution to the sweep side and the sweep side solution to the feed side to retain a desired solution composition.
5. The method as claimed in claim 1, wherein the method comprises adding an external process solution to at least one of the feed side solution and the sweep side solution, wherein the external solution comprises a system level feed solution and a system level sweep solution.
6. The method as claimed in claim 4, wherein the method comprises adding the external process solution to at least one of the feed side solution and the sweep side solution, wherein the external solution comprises the system level feed solution and the system level sweep solution.

7. The method as claimed in claim 1, wherein receiving the system level feed solution to
the feed side of the SRO system and the system level sweep solution to the sweep side of
the SRO system comprises:
r ecei v i n g, by at least one feed side tank, the system level feed solution and supplying the pass level feed solution to the first side of the semi-permeable membrane, wherein the at least one feed side tank is part of the feed side of the SRO system; and
receiving, by at least one sweep side tank, the system level sweep solution and supplying the pass level sweep solution to the second side of the semi-permeable membrane, wherein the at least one sweep side tank is part of the sweep side of the SRO system.
8. The method as claimed in claim 1, wherein exerting the pressure on the first side of the
semipermeable membrane comprises:
actuating a piston on a feed side solution that is hydraulically connected to the first side of the semipermeable membrane;
applying pressure through a hydraulic fluid in a hydraulic chamber of the at least one feed side tank with the feed side solution in a feed chamber of the feed side tank, wherein the at least one feed side tank comprises at least two chambers separated by at least one movable partition;
actuating a piston on the feed side solution present in one of a chamber of the feed side tank, wherein the feed side tank comprises at least two chambers separated by at least one movable partition;
applying pressure through a hydraulic fluid in direct hydraulic contact with the feed side solution in the at least one feed side tank;
applying pressure directly on the feed side solution by filling the at least one feed side tank completely with the feed side solution; and

applying pressure through the high-pressure pump, the ERD and the booster pump when using an unpressurized tank with at least one chamber and an unpressurized tank with at least one movable partition with at least two chambers.
9. The method as claimed in claim 1, wherein receiving the system level feed solution to the feed side of the SRO system and the system level sweep solution to the sweep side of the SRO system, comprises:
receiving a system level feed solution in at least one feed side holding chamber and supplying a pass level feed solution from the at least one feed side holding chamber to a feed side circulation loop;
receiving a system level sweep solution in at least one sweep side holding chamber and supplying pass level sweep solution from the at least one sweep side holding chamber to a sweep side circulation loop;
exerting, by the pressurizing unit, a pressure on the pass level feed solution on first side of the semipermeable membrane such that, the permeate solution from the pass level feed solution passes from the first side of the semipermeable membrane to the second side of the semipermeable membrane, wherein the permeate solution has a different osmotic pressure than the pass level feed solution;
discharging, by the semipermeable membrane, the pass level concentrate solution from the first side of the semi-permeable membrane, on passing the permeate solution to the second side of the semipermeable membrane, wherein the discharged pass level concentrate solution acts as the pass level feed solution to a subsequent pass until the system level concentrate solution is generated;
discharging, by the semipermeable membrane, the pass level diluate solution from second side of the semi-permeable membrane, on receiving the permeate solution from the first side of the semi permeable membrane, wherein the discharged pass level diluate solution acts as the pass level sweep solution to a subsequent pass until the system level diluate solution is generated;

adding an external process solution to the feed side circulation loop and removing a diluate solution from the sweep side circulation loop to maintain a required pressure in the feed side circulation loop and the sweep side circulation loop;
supplying the system level feed solution to the at least one feed side holding chamber for a next operation cycle while simultaneously displacing the system level concentrate solution of a previous operation cycle from the at least one feed holding chamber to an external sink;
supplying the system level sweep solution to the at least one sweep side holding chamber for the next operation cycle while simultaneously displacing the system level diluate solution of the previous operation cycle from the at least one sweep side holding chamber to the external sink;
initiating a solution change over sequence on a feed side circulation loop by hydraulically connecting at least one feed side holding chamber and the feed side circulation loop, when the pass level concentration solution in the feed side circulation loop reaches concentration of the system level concentrate solution;
transporting the system level concentrate solution from the feed side circulation loop into the at least one feed side holding chamber thereby displacing the system level feed solution from the at least one feed side holding chamber to the feed side circulation loop, while achieving separation in a corresponding SRO unit during the entire solution change over sequence, wherein the SRO unit includes the semipermeable membrane;
hydraulically disconnecting the at least one feed side holding chamber from the feed side circulation loop and initiating a next semi batch process;
initiating a solution change over sequence on the sweep side circulation loop by hydraulically connecting the at least one sweep side holding chamber and the sweep side circulation loop, when the pass level diluate solution in the sweep side circulation loop reaches concentration of the system level diluate solution;
transporting the system level diluate solution from the sweep side circulation loop into the at least one sweep side holding chamber thereby displacing the system level

sweep solution from the at least one sweep side holding chamber to the circulation loop, while achieving separation in the SRO unit during the entire solution change over sequence; and
hydraulically disconnecting the at least one sweep side holding chamber from the sweep side circulation loop and initiating the next semi batch process.
10. The method as claimed in claim 1, wherein receiving the system level feed solution to the feed side of the SRO system and the system level sweep solution to the sweep side of the SRO system comprises:
receiving by at least one feed side tank the system level feed solution and supplying the pass level feed solution to the first side of the semi-permeable membrane, wherein the at least one feed side tank is part of the feed side of the SRO system;
receiving the system level sweep solution in at least one sweep side holding chamber and supplying pass level sweep solution from the at least one sweep side holding chamber to the sweep side circulation loop;
exerting, by the pressurizing unit, a pressure on the pass level feed solution on the first side of the semipermeable membrane such that, the permeate solution from the pass level feed solution passes from the first side of the semipermeable membrane to the second side of the semipermeable membrane, wherein the permeate solution has a different osmotic pressure than the pass level feed solution;
discharging, by the semipermeable membrane, a pass level concentrate solution from the first side of the semi-permeable membrane, on passing the permeate solution to the second side of the semipermeable membrane, wherein the discharged pass level concentrate solution acts as the pass level feed solution in a subsequent pass until a system level concentrate solution is generated;
discharging, by the semipermeable membrane, a pass level diluate solution from second side of the semi-permeable membrane, on receiving the permeate solution from the first side of the semi permeable membrane, wherein the discharged

pass level diluate solution acts as the pass level sweep solution in a subsequent pass until a system level diluate solution is generated;
removing diluate solution from the sweep side circulation loop to maintain a required pressure in the sweep side circulation loop;
supplying the system level sweep solution to the at least one sweep side holding chamber for the next operation cycle while simultaneously displacing the system level diluate solution of the previous operation cycle from the at least one sweep side holding chamber to an external sink;
initiating a solution change over sequence on the sweep side circulation loop by hydraulically connecting the at least one sweep side holding chamber and the sweep side circulation loop, when the pass level diluate solution in the sweep side circulation loop reaches concentration of the system level diluate solution;
transporting the system level diluate solution from the sweep side circulation loop into the at least one sweep side holding chamber thereby displacing the system level sweep solution from the at least one sweep side holding chamber to the circulation loop, while achieving separation in the SRO unit during the entire solution change over sequence; and
hydraulically disconnecting the at least one sweep side holding chamber from the sweep side circulation loop and initiating a next semi batch process.
11. The method as claimed in claim 1, wherein receiving the system level feed solution to the feed side of the SRO system and the system level sweep solution to the sweep side of the SRO system comprises:
receiving the system level feed solution in the at least one feed side holding chamber and supplying pass level feed solution from the at least one feed side holding chamber to the feed side circulation loop;
receiving by at least one sweep side tank the system level sweep solution and supplying the pass level sweep solution to the second side of semi-permeable

membrane, wherein the at least one sweep side tank is part of the sweep side of the SRO system;
exerting, by the pressurizing unit, a pressure on the pass level feed solution on first side of the semipermeable membrane such that, the permeate solution from the pass level feed solution passes from the first side of the semipermeable membrane to the second side of the semipermeable membrane, wherein the permeate solution has a different osmotic pressure than the pass level feed solution;
discharging the pass level concentrate solution from the first side of the semi-permeable membrane on passing the permeate solution to the second side of the semipermeable membrane, wherein the discharged pass level concentrate solution acts as the pass level feed solution in a subsequent pass until the system level concentrate solution is generated;
discharging the pass level diluate solution from second side of the semi-permeable membrane on receiving the permeate solution from the first side of the semi permeable membrane, wherein the discharged pass level diluate solution acts as the pass level sweep solution in a subsequent pass unti l the system level diluate solution is generated;
adding an external process solution to the feed side circulation loop to maintain a required pressure in the feed side circulation loop;
supplying the system level feed solution to the at least one feed side holding chamber for the next operation cycle while simultaneously displacing the system level concentrate solution of a previous operation cycle from the at least one feed side holding chamber to an external sink;
initiating a solution change over sequence on the feed side circulation loop by hydraulically connecting at least one feed side holding chamber and the feed side circulation loop, when the pass level concentrate solution in the feed side circulation loop reaches concentration of the system level concentrate solution;

transporting the system level concentrate solution from the feed side circulation loop into the at least one feed side holding chamber thereby displacing the system level feed solution from the at least one feed side holding tank to the feed side circulation loop, while achieving separation in the SRO unit during the entire solution change over sequence; and
hydraulically disconnecting the at least one feed side holding chamber from the feed side circulation loop and initiating the next semi batch process.
12. The method as claimed in claim 1, wherein receiving the system level feed solution to the feed side of the SRO system and the system level sweep solution to the sweep side of the SRO system comprises:
receiving by at least one feed side tank the system level feed solution and supplying the pass level feed solution to the first side of semi-permeable membrane, wherein the at least one feed tank is part of the feed side of the SRO system;
receiving a system level sweep solution from an external source and supplying the pass level sweep solution to the sweep side circulation loop;
exerting, by a pressurizing unit, a pressure on the pass level feed solution on first side of the semipermeable membrane such that, a permeate solution from the pass level feed solution passes from the first side of the semipermeable membrane to the second side of the semipermeable membrane, wherein the permeate solution has a different osmotic pressure than the pass level feed solution;
discharging, by the semipermeable membrane, a pass level concentrate solution from the first side of the semi-permeable membrane on passing the permeate solution to the second side of the semipermeable membrane, wherein the discharged pass level concentrate solution acts as the pass level feed solution to a subsequent pass until a system level concentrate solution is generated;
discharging, by the semipermeable membrane, a pass level diluate solution from second side of the semi-permeable membrane on receiving the permeate

solution from the first side of the semi permeable membrane, wherein the discharged pass level diluate solution acts as the pass level sweep solution to a subsequent pass until a system level diluate solution is generated; and
discharging a portion of the pass level diluate as the system level diluate to an external sink.
13. The method as claimed in claim 1, wherein receiving the system level feed solution to the feed side of the SRO system and the system level sweep solution to the sweep side of the SRO system comprises:
receiving the system level feed solution from the external source and supplying the pass level feed solution to the feed side circulation loop;
receiving by at least one sweep tank the system level sweep solution and supplying the pass level sweep solution to the second side of semi-permeable membrane, wherein the at least one sweep tank is part of the sweep side of the SRO system;
exerting a pressure on the pass level feed solution on first side of the semipermeable membrane such that, the permeate solution from the pass level feed solution passes from the first side of the semipermeable membrane to the second side of the semipermeable membrane, wherein the permeate solution has a different osmotic pressure than the pass level feed solution;
discharging the pass level concentrate solution from the first side of the semi-permeable membrane on passing the permeate solution to the second side of the semipermeable membrane, wherein the discharged pass level concentrate solution acts as the pass level feed solution in a subsequent pass until the system level concentrate solution is generated;
discharging the pass level diluate solution from second side of the semi-permeable membrane on receiving the permeate solution from the first side of the semi permeable membrane, wherein the discharged pass level diluate solution acts as the pass

level sweep solution in a subsequent pass unti l the system level diluate solution is generated; and
discharging a portion of the pass level concentrate as the system level concentrate to the external sink.
14. The method as claimed in claim 1, wherein receiving the system level feed solution to the feed side of the SRO system and the system level sweep solution to the sweep side of the SRO system comprises:
receiving a system level feed solution in at least one feed side holding chamber and supplying the pass level feed solution from the holding chamber to a feed side circulation loop;
receiving a system level sweep solution from the external source and supplying the pass level sweep solution to the sweep side circulation loop;
exerting, by a pressurizing unit, a pressure on the pass level feed solution on first side of the semipermeable membrane such that, a permeate solution from the pass level feed solution passes from the first side of the semipermeable membrane to the second side of the semipermeable membrane, wherein the permeate solution has a different osmotic pressure than the pass level feed solution;
discharging, by the semipermeable membrane, a pass level concentrate solution from the first side of the semi-permeable membrane on passing the permeate solution to the second side of the semipermeable membrane, wherein the discharged pass level concentrate solution acts as the pass level feed solution in a subsequent pass until a system level concentrate solution is generated;
discharging, by the semipermeable membrane, a pass level diluate solution from second side of the semi-permeable membrane on receiving the permeate solution from the first side of the semi permeable membrane, wherein the discharged pass level diluate solution acts as the pass level sweep solution in a subsequent pass until a system level diluate solution is generated;

adding an external process solution to the feed side circulation loop to maintain a required pressure in the feed side circulation loop and discharging a portion of the pass level diluate as the system level diluate to an external sink;
supplying the system level feed solution to the feed side holding chamber for a next operation cycle while simultaneously displacing the system level concentrate solution of a previous operation cycle from the holding chamber to the external sink;
initiating the solution change over sequence on feed side circulation loop by hydraulically connecting at least one feed side holding chamber and the feed side circulation loop, when the pass level concentration solution in the feed side circulation loop reaches concentration of the system level concentrate solution;
transporting the system level concentrate solution from the feed side circulation loop into the feed side holding chamber thereby displacing the system level feed solution from the holding chamber to the circulation loop, while achieving separation in the SRO unit during the entire solution change over sequence;
hydraulically disconnecting the holding chamber from the feed side circulation loop and initiating a next semi batch process; and
discharging a portion of the pass level diluate solution as the system level diluate to an external sink.
15. The method as claimed in claim 1, wherein receiving the system level feed solution to the feed side of the SRO system and the system level sweep solution to the sweep side of the SRO system comprises:
receiving the system level feed solution from the external source and supplying the pass level feed solution to the feed side circulation loop;
receiving a system level sweep solution in at least one sweep side holding chamber and supplying the pass level sweep solution from the holding chamber to the sweep side circulation loop;

exerting, by the pressurizing unit, a pressure on the pass level feed solution on first side of the semipermeable membrane such that, a permeate solution from the pass level feed solution passes from the first side of the semipermeable membrane to the second side of the semipermeable membrane, wherein the permeate solution has a different osmotic pressure than the pass level feed solution;
discharging, by the semipermeable membrane, a pass level concentrate solution from the first side of the semi-permeable membrane on passing the permeate solution to the second side of the semipermeable membrane, wherein the discharged pass level concentrate solution acts as the pass level feed solution in a subsequent pass until a system level concentrate solution is generated;
discharging, by the semipermeable membrane, a pass level diluate solution from second side of the semi-permeable membrane on receiving the permeate solution from the first side of the semi permeable membrane, wherein the discharged pass level diluate solution acts as the pass level sweep solution in a subsequent pass until a system level diluate solution is generated;
discharging a portion of the pass level concentrate as the system level concentrate to the external sink and removing diluate solution from the sweep side circulation loop to maintain a required pressure in the feed side circulation loop and the sweep side circulation loop;
supplying the system level sweep solution to the sweep side holding chamber for the next operation cycle while simultaneously displacing the system level diluate solution of the previous operation cycle from the sweep side holding chamber to the external sink;
initiating a solution change over sequence on sweep side circulation loop by hydraulically connecting at least one sweep side holding chamber and the sweep side circulation loop, when the pass level diluate solution in the sweep side circulation loop reaches concentration of the system level diluate solution;

transporting the system level diluate solution from the sweep side circulation loop into the sweep side holding chamber thereby displacing the system level sweep solution from the sweep side holding chamber to the circulation loop, while achieving separation in the SRO unit during the entire solution change over sequence; and
hydraulically disconnecting the sweep side holding chamber from the sweep side circulation loop and initiating a next semi batch process.
16. The method as claimed in of claim 1, wherein the method further comprises:
a. supplying a stage level concentrate solution from a first separation stage as a stage level
sweep solution to a second separation stage, wherein each of the separation stage
comprises the SRO system, wherein the feed side and the sweep side of the SRO system
is operated by at least one of at least one tank, at least one holding chamber, an external
source and an external sink;
b. supplying a stage level sweep solution to the first separation stage from an external
source and discharging the stage level diluate solution from the first separation stage to
an external sink;
c. supplying a stage level diluate solution from the second separation stage as a stage level
feed solution to the first separation stage;
d. supplying a stage level concentrate solution from the second separation stage as a stage
level sweep solution to the third separation stage;
e. supplying a stage level diluate solution from the third separation as a stage level feed
solution to the second separation stage; and
f. repeating the steps (a-e) till nth separation stage, wherein the stage level feed solution to
the nth separation stage is supplied from an external source and stage level concentrate
solution from the nth separation stage is discharged to the external sink.
17. The method as claimed in claim 16, wherein the first separation stage, second separation
stage, third separation stage to nth separation stage are arranged in an array.

18. The method as claimed in claim 16, wherein a plurality of separation stages are arranged in the array such that the process solution is transported from one side of the semi permeable membrane to another side of the semi permeable membrane through a direct hydraulic connection or through a residual solution carryover.
19. The method as claimed in claim 16, wherein the method comprises:
adding process solution from an external source to a separation stage other than the first and nth separation stage or removing the stage level process solution from the separation stage other than the first or the nth stage to the external sink.
20. The method as claimed in claim 18, wherein the method further comprises
adding process solution from an external source to a separation stage other than the first and the nth separation stage or removing the stage level process solution from the separation stage other than the first or the nth separation stage to the external sink.
21. The method as claimed in claim 1, wherein the method comprises:
a. receiving by the first separation stage the stage level diluate solution from the second
separation stage and receiving a process solution from an external source by the first
separation stage, wherein each of the separation stage comprises the SRO system,
wherein the feed side and the sweep side of the SRO system is operated by at least one of
at least one tank, at least one holding chamber, an external source and an external sink;
b. combining by the first separation stage the stage level diluate from the second separation
stage and the process solution from the external source and using as a stage level feed
solution and the stage level sweep solution for the first separation stage;
c. discharging the stage level diluate solution from the first separation stage to an external
sink and stage level concentrate solution from the first separation stage to the second
separation stage;

d. receiving by the second separation stage the stage level diluate solution from the third
separation stage and the stage level concentrate solution from the first separation stage;
e. combining by the second separation stage the stage level diluate solution from the third
separation stage and the stage level concentrate solution from the first separation stage
and used as a stage level feed solution and the stage level sweep solution for the second
separation stage;
f. discharging stage level concentrate solution and stage level diluate solution from the
second separation stage;
g. receiving by the third separation stage a stage level concentrate solution of the second
separation stage and stage level diluate solution from the fourth separation stage and
combining and supplying as a stage level feed solution and stage level sweep solution for
the third separation stage; and
h. discharging stage level concentrate solution and stage level diluate solution from the
third separation stage; i. repeating the steps (a-h), till the nth separation stage, wherein at least one of a stage level
concentrate solution from n-1 stage and process solution from the external source are
released; j. supplying one of the stage level concentrate solution from the n-1th separation stage and
a combination of the stage level concentrate solution from the n-1 th separation stage and
the process solution from the external source as a stage level feed solution and stage
level sweep solution for the nth separation stage; and k. discharging stage level concentrate solution from the nth separation stage to an external
sink and discharging the stage level diluate solution from the nth separation stage to the
n-1 separation stage.
22. The method as claimed in claim 21, wherein the first separation stage, second separation stage, third separation stage to nth separation stage are arranged in an array.

23. The method as claimed in claim 21, wherein the method comprises:
adding process solution from the external source to a separation stage other than the first stage or removing the stage level process solution from the separation stage other than the first or the nth separation stage to the external sink.
24. The method as claimed in of claim 1, wherein the method comprises:
a. supplying a stage level concentrate solution from a first separation stage as a stage level
feed solution to a second separation stage, wherein each of the separation stage
comprises the at least one SRO system;
b. supplying a stage level feed solution to the first separation stage from an external source
and discharging the stage level diluate solution from the first separation stage to an
external sink, wherein each of the separation stage comprises at least one SRO system,
wherein the feed side and the sweep side of the SRO system is operated by one of at least
one tank, at least one holding chamber, an external source and an external sink;
c. supplying a stage level diluate solution from the second separation stage as a stage level
sweep solution to the first separation stage;
d. supplying a stage level concentrate solution from the second separation stage as a stage
level feed solution to the third separation stage;
e. supplying a stage level diluate solution from the third separation as a stage level sweep
solution to the second separation stage; and
f. r ep eat i n g the steps ( a-e) till nth separ at i o n s t age , w h erein t h e s t age l ev el co n cen t rat e
solution from the n-1 separation stage is supplied as stage level feed solution to the nth
separation stage and either a portion of the feed solution to the nth separation stage or a
portion of the concentrate solution from the nth separation stage or both are supplied as
stage level sweep solution to the nth separation stage; further a portion of the concentrate
solution from the nth separation stage is discharged to an external sink and the stage level
diluate solution from the nth separation stage is supplied as stage level sweep solution to
n-1 separation stage.

25. The method as claimed in claim 24, wherein the first separation stage, second separation stage, third separation stage to nth separation stage are arranged in an array.
26. The method as claimed in claim 24, wherein a plurality of separation stages are arranged in the ar ra y such that the process solution is transported from one side of the semi permeable membrane to another side of the semi permeable membrane through a direct hydraulic connection or through a residual solution carryover.
27. The method as claimed in claim 24, wherein the method comprises:
adding process solution from an external source to a separation stage other than the first stage or removing the stage level process solution from the separation stage other than the first or the nth stage to an external sink.
28. The method as claimed in claim 26, wherein the method comprises:
adding process solution from an external source to a separation stage other than the first stage or removing the stage level process solution from the separation stage other than the first or the nth stage to the external sink.
29. A sweep reverse osmosis (SRO) system for pressure-driven liquid separation, the SRO
system comprises:
a. a feed side and a sweep side configured to:
receive a s ystem level feed solution to a feed side of the SRO system and a system level sweep solution to a sweep side of the SRO system;
b. a semi-permeable membrane configured to:
receive a pass level feed solution from the system level feed solution to a first side of the semi-permeable membrane, wherein the pass level feed has a first osmotic pressure;

receive a pass level sweep solution from the system level sweep to a second side of the semi-permeable membrane, wherein the pass level sweep has a second osmotic pressure;
c. a pressurizing unit configured to:
exert a pressure on the pass level feed solution on first side of the semipermeable membrane such that, a permeate solution from the pass level feed solution passes from the first side of the semipermeable membrane to the second side of the semipermeable membrane, wherein the permeate solution has a different osmotic pressure than the pass level feed solution, , wherein the pressurizing unit includes at least one of an energy recovery device (ERD), a high pressure pump, a booster pump, a piston, an hydraulic fluid and a a pneumatic fluid;
d. the semi-permeable membrane unit configured to:
discharge a pass level concentrate solution from the first side of the semi-permeable membrane on passing the permeate solution to the second side of the semipermeable membrane, wherein the discharged pass level concentrate solution acts as the pass level feed solution to any of its subsequent pass level feed until a system level concentrate solution is generated;
discharge a pass level diluate solution from second side of the semi-permeable membrane on receiving the permeate solution from the first side of the semi permeable membrane, wherein the discharged pass level diluate solution acts as the pass level sweep solution to any of its subsequent pass level sweep until a system level diluate solution is generated;
e. a feed side circulation pump and a sweep side circulation pump configured to:
remove the system level concentrate solution and the system level diluate
solution; and
f. the SRO system configured to:
repeat steps (a-f) to continue with subsequent operation cycles.

30. The SRO system of claim 29, wherein the system further comprises:
at least one feed side holding chamber hydraulically connected to first side of the
semipermeable membrane, configured to:
establish intermittent hydraulic communication with the first side of the semi
permeable membrane for exchanging process solution with a feed side circulation loop; receive system level feed solution from an external source; and discharge the system level concentrate solution to an external sink;
at least one sweep side holding chamber hydraulically connected to the second side of
the semipermeable membrane, configured to:
establish intermittent hydraulic communication with second side of the
semipermeable membrane for exchanging process solution with sweep side circulation
loop;
receive system level sweep solution from an external source; and discharge the system level diluate solution to an external sink.
31. The SRO system as claimed in claim 30, wherein a hydraulic connection to at least one external source containing a process solution supplying to at least one feed side holding chamber, a feed side circulation loop, at least one sweep side holding chamber and a sweep side circulation loop.
32. The SRO system as claimed in claim 29, wherein the SRO system comprises:
at least one feed side tank hydraulically connected to the first side of the semipermeable membrane is configured to:
receive the system level feed side solution, to store the process solution, to supply the pass level feed side solution to the first side of the semi permeable membrane, to collect the pass level concentrate solution from the first side of the semi permeable membrane, to collect pass level sweep side solution and to collect pass level diluate solution;

at least one sweep side tank hydraulically connected to the second side semi permeable membrane configured to:
receive the system level sweep side solution, to store the process solution, to supply the pass level sweep side solution to the second side of the semi permeable membrane, to collect pass level diluate solution from the second side of the semi permeable membrane, to collect the pass level feed solution and to collect pass level concentrate solution;
at least one external source configured to supply a process solution to the at least one feed side tank, and at least one sweep side tank.
33. The SRO system as claimed in claim 29, wherein the at least one feed side tank and the
at least one sweep side tank comprises at least one of:
an unpressurized tank;
a piston pressurized tank;
a piston pressurized tank with at least two chambers separated by at least one movable
partition;
an indirect hydraulically pressurized tank with at least two chambers separated by at least
one movable partition;
a direct hydraulically pressurized tank;
a direct feed pressurized tank; and
an unpressurized tank with at least two chambers separated by at least one movable
partition.
34. The SRO system as claimed in claim 29, wherein the system comprises:
at least one feed side tank hydraulically connected to the first side of the semi permeable membrane configured to:
receive the system level feed side solution, to store the process solution, to supply the pass level feed side solution to the first side of the semi permeable membrane, to

collect the pass level concentrate solution from the first side of the semi permeable
membrane, to collect pass level sweep side solution and to collect pass level diluate
solution;
at least one sweep side holding chamber hydraulically connected to the second side of
the semi permeable membrane configured to:
establish intermittent hydraulic communication with second side of the semipermeable membrane for exchanging process solution with sweep side circulation loop;
receive system level sweep solution from an external source;
discharge the system level diluate solution to an external sink; and at least one external source configured to supply a process solution to the at least one feed side tank, at least one sweep side holding chamber and sweep side circulation loop.
35. The SRO system as claimed in claim 29, wherein the system comprises:
at least one feed side holding chamber hydraulically connected to first side of the semipermeable membrane, configured to:
establish intermittent hydraulic communication with the first side of the semi permeable membrane for exchanging process solution with a feed side circulation loop;
receive system level feed solution from an external source; and discharge the system level concentrate solution to an external sink;
at least one sweep side tank hydraulically connected to the second side semi permeable membrane configured to:
receive the system level sweep side solution, to store the process solution, to supply the pass level sweep side solution to the second side of the semi permeable membrane, to collect pass level diluate solution from the second side of the semi permeable membrane, to collect the pass level feed side solution and to collect pass level concentrate solution;

at least one external source configured to supply the process solution to the at least one feed side holding chamber, the feed side circulation loop and the at least one sweep side tank.
36. The SRO system as claimed in claim 29, wherein the system comprises:
at least one feed side tank hydraulically connected to the first side of the semi permeable membrane configured to: receive the system level feed side solution, to store the process solution, to supply the pass level feed side solution to the first side of the semi permeable membrane, to collect the pass level concentrate solution from the first side of the semi permeable membrane, to collect pass level sweep side solution and to collect pass level diluate solution;
at least one external source hydraulically connected to the second side of the semi permeable membrane configured to, supply system level sweep solution;
at least one external sink hydraulically connected to the second side of the semi permeable membrane configured to, remove the system level diluate solution; and
at least one external source configured to, supply the process solution to the at least one feed side tank and the sweep side circulation loop.
37. The SRO system as claimed in claim 29, wherein the system further comprises:
at least one external source hydraulically connected to the first side of the semi
permeable membrane configured for, supplying the system level feed solution;
at least one external sink hydraulically connected to first side of the semi permeable
membrane configured for, removing the system level concentrate solution;
at least one sweep side tank hydraulically connected to the second side semi permeable
membrane configured to:
receive the system level sweep side solution, to store the process solution, to supply the pass level sweep side solution to the second side of the semi permeable membrane, to collect pass level diluate solution from the second side of the semi

permeable membrane, to collect the feed side solution and to collect pass level concentrate solution; and
at least one external source configured to supply the process solution to the feed side circulation loop and the at least one sweep side tank.
38. The SRO system as claimed in claim 29, wherein the system further comprises:
at least one feed side holding chamber hydraulically connected to the first side of the
semipermeable membrane, configured to:
establish intermittent hydraulic communication with the first side of the semi
permeable membrane for exchanging process solution with a feed side circulation loop; receive system level feed solution from an external source; and discharge the system level concentrate solution to an external sink.
at least one external source hydraulically connected to the second side of the
semipermeable membrane for supplying system level sweep solution;
at least one external sink hydraulically connected to the second side of the
semipermeable membrane for removing system level diluate solution; and
at least one external source configured to supply the process solution to the at least one
feed side holding chamber, the feed side circulation loop and the sweep side circulation
loop.
39. The SRO system as claimed in claim 29, wherein the system comprises:
at least one external source hydraulically connected to the first side of the semipermeable
membrane for supplying system level feed solution;
at least one external sink hydraulically connected to the first side of the semipermeable
membrane for removing system level concentrate solution;
at least one sweep side holding chamber hydraulically connected to the second side of
the semi permeable membrane configured to:

establish intermittent hydraulic communication with second side of the semipermeable membrane for exchanging process solution with sweep side circulation loop;
receive system level sweep solution from an external source;
discharge the system level diluate solution to an external sink; and at least one external source configured to supply the process solution to the feed side circulation loop, the at least one sweep side holding chamber and the sweep side circulation loop.
40. The SRO system as claimed in claim 33, wherein the unpressurized tank with the at least
two chambers separated by the at least one movable partition, is configured to:
supply from one of the at least two chambers the at least one of the pass level feed solution and the pass level sweep solution to the first side of the semipermeable membrane and the second side of the semipermeable membrane respectively; and collect at leas t one o f t h e pas s l ev el concent rat e solution and the pass level diluate solution from the first side of the semipermeable membrane and the second side of the semipermeable membrane respectively in one of the at least two chambers.
41. The SRO system as claimed in claim 33, wherein the piston pressurized tank with at least
two chambers separated by the at least one movable partition, is configured to:
supply from one of the at least two chamber the pass level feed solution to the first side of the semi permeable membrane; and
collect the pass level concentrate solution from the fist side of the semi permeable membrane in one of the a at least two chambers.
42. The SRO system as claimed in claim 33, wherein the indirect hydraulically pressurized
tank with the at least two chambers separated by the at least one movable partition,
configured to:

supply from one of the at least two chamber the pass level feed solution to the first side of the semi permeable membrane; and
collect the pass level concentrate solution from the fist side of the semi permeable membrane in one of the at least two chambers.
43. A system for pressure driven separation, comprising a plurality of SRO systems wherein the system is configured to:
a. supply a stage level concentrate solution from a first separation stage as a stage level
sweep solution to a second separation stage, wherein the stage level concentrate solution
is an output of at least one SRO system of the plurality of SRO system, wherein each of
the separation stage comprises at least one SRO system of the plurality of the SRO
systems;
b. supply a stage level sweep solution to the first separation stage from an external source
and discharging the stage level diluate solution from the first separation stage to an
external sink, wherein the stage level sweep solution is an output of the at least one SRO
system of the plurality of SRO system, wherein a feed side and a sweep side of the at
least one SRO system is operated by at least one of at least one tank, at least one holding
chamber, an external source and an external sink;
c. supply a stage level diluate solution from the second separation stage as a stage level
feed solution to the first separation stage;
d. supply a stage level concentrate solution from the second separation stage as a stage
level sweep solution to the third separation stage;
e. supply a stage level diluate solution from the third separation as a stage level feed
solution to the second separation stage; and
f. repeat the steps (a-e) till nth separation stage, wherein the stage level feed solution to the
nth separation stage is supplied from an external source and stage level concentrate
solution from the nth separation stage is discharged to an external sink.

44. The system as claimed in claim 43, wherein one of the at least one holding chamber and the at least one tank is shared between any of the separation stages.
45. The system as claimed in claim 43, wherein the first separation stage, second separation stage, third separation stage to nth separation stage are arranged in an array.
46. The system as claimed in claim 43, wherein the at least one SRO system of the plurality of SRO system is configured to: transport the process solution from a first side of a semi permeable membrane to a second side of the semi permeable membrane through a direct hydraulic connection or through a residual solution carryover.
47. The system as claimed in claim 43, wherein the system is further configured to:
add process solution from an external source to a separation stage other than the first and nth separation stage or remove the stage level process solution from the separation stage other than the first or the nth stage to the external sink.
48. The system as claimed in claim 46, wherein the at least one SRO system of the plurality
of SRO system is further configured to:
add process solution from an external source to a separation stage other than the first and the nth separation stage or remove the stage level process solution from the separation stage other than the first or the nth separation stage to the external sink.
49. The system as claimed in claim 43, wherein the system is further configured to:
a. r ecei v e b y t h e fir st separ at i o n s t age the sta ge l evel d i l u at e solution from the second separation stage and receiving a process solution from an external source by the first separation stage;

b. combine by the first separation stage the stage level diluate from the second separation
stage and the process solution from the external source and used as a stage level feed
solution and the stage level sweep solution for the first separation stage;
c. discharge the stage level diluate solution from the first separation stage to an external
sink and stage level concentrate solution from the first separation stage to the second
separation stage;
d. receive by the second separation stage the stage level diluate solution from the third
separation stage and the stage level concentrate solution from the first separation stage;
e. combine by the second separation stage, the stage level diluate solution from the third
separation stage and the stage level concentrate solution from the first separation stage
and used as a stage level feed solution and the stage level sweep solution for the second
separation stage;
f. discharge stage level concentrate solution and stage level diluate solution from the
second separation stage;
g. receive by the third separation stage a stage level concentrate solution from the second
separation stage and a stage level diluate solution from the fourth separation stage;
h. combine by the third separation stage, the stage level concentrate solution from the
second separation stage and the stage level diluate solution from the fourth separation
stage and used as a stage level feed solution and stage level sweep solution for the third
separation stage; i. discharge stage level concentrate solution and stage level diluate solution from the third
separation stage; j. repeat the steps (a-i), till the nth separation stage, wherein receiving stage level
concentrate solution from n-1 stage and process solution from the external source; k. combine the stage level concentrate solution from the n-1 th separation stage and the
process solution from the external source, and supply as a stage level feed solution and
stage level sweep solution for the nth separation stage; and

l. discharge stage level concentrate solution from the nth separation stage to an external sink and discharge the stage level diluate solution from the nth separation stage to the n-1 separation stage.
50. The system as claimed in claim 49, wherein the first separation stage, second separation stage, third separation stage to nth separation stage are arranged in an array.
51. The system as claimed in claim 49, wherein the system is further configured to:
add process solution from the external source to a separation stage other than the first stage or remove the stage level process solution from the separation stage other than the first or the nth separation stage to the external sink.
52. The system as claimed in claim 49, wherein the system further comprises:
at least one accumulator configured to:
store the stage level process solution and supply the stage level process solution.
53. A system for pressure driven separation, comprising a plurality of SRO systems, wherein
the system is configured to:
a. supply a stage level concentrate solution from a first separation stage as a stage level
feed solution to a second separation stage;
b. supply a stage level feed solution to the first separation stage from an external source and
discharge the stage level diluate solution from the first separation stage to an external
sink, wherein each of the separation stage comprises at least one SRO system, wherein
the feed side and the sweep side of the SRO system is operated by one of at least one
tank, at least one holding chamber, an external source and an external sink;
c. supply a stage level diluate solution from the second separation stage as a stage level
sweep solution to the first separation stage;

d. supply a stage level concentrate solution from the second separation stage as a stage
level feed solution to the third separation stage;
e. supply a stage level diluate solution from the third separation as a stage level sweep
solution to the second separation stage; and
f. repeat the steps (a-e) till nth separation stage, wherein the stage level concentrate solution
from the n-1 separation stage supplied as stage level feed solution to the nth separation
stage and either a portion of the feed solution to the nth separation stage or a portion of
the concentrate solution from the nth separation stage or both are supplied as stage level
sweep to the nth separation stage; further a portion of the concentrate solution from the
nth separation stage is discharged to an external sink and the stage level diluate solution
from the nth separation stage is supplied as stage level sweep solution to n-1 separation
stage.
54. The system as claimed in claim 53, wherein the first separation stage, second separation stage, third separation stage to nth separation stage are arranged in an array.
55. The system as claimed in claim 53, wherein the at least one SRO system of the plurality of SRO system is configured to transport the process solution from one side of the semi permeable membrane to another side of the semi permeable membrane through a direct hydraulic connection or through a residual solution carryover.
56. The system as claimed in claim 53, wherein the system is further configured to:
add process solution from an external source to a separation stage other than the first stage or removing the stage level process solution from the separation stage other than the first or the nth stage to the external sink.
57. The system as claimed in claim 55, wherein the system is further configured to:

add process solution from an external source to a separation stage other than the first stage or removing the stage level process solution from the separation stage other than the first or the nth stage to the external sink.
58. The system as claimed in claim 53, wherein the system further comprises:
at least one accumulator configured to:
store the stage level process solution and supply the stage level process solution.
59. The system as claimed in claim 53, wherein one of the at least one holding chamber and
the at least one tank is shared between any of the separation stages.