WO2016193855A1

WO2016193855A1 - Reverse osmosis based potable water system with improved yield

Info

Publication number: WO2016193855A1
Application number: PCT/IB2016/053007
Authority: WO
Inventors: Rohit Kumar MITTAL; Naveen Kumar
Original assignee: Mittal Rohit Kumar; Naveen Kumar
Priority date: 2015-06-02
Filing date: 2016-05-23
Publication date: 2016-12-08
Also published as: GB2554580A; GB201717736D0

Abstract

The present disclosure relates to a Reverse Osmosis based potable water system (200) for water filtration that can provide improved yield of potable water thereby reducing the wastage of water. In an embodiment, the improvement in yield is achieved by providing two RO units (208 and 220) that can be configured in series in such as a way that retentate from the first RO unit (208) is fed as input to the second RO unit (220), through a control valve to get an additional yield of potable water. The potable water purification system 200 includes means, such as piping unit 226 or pumps (210, 218) for maintaining required flow and appropriate pressure level of feed water at different stages, so as to get high yield of pure water and increase the life of the semipermeable membranes.

Description

REVERSE OSMOSIS BASED POTABLE WATER SYSTEM WITH

IMPROVED YIELD

TECHNICAL FIELD

[0001] The present disclosure relates generally to the field of water filtration. In particular, it pertains to a reverse osmosis potable water system that provides improved yield and thus reduces wastage of water.

BACKGROUND

[0002] Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.

[0003] A large population of the world especially in third world countries and in remote areas does not have access to potable water supply. Installation of water purification and distribution infrastructure is expensive and therefore beyond the capacity of many communities. Even at places where such infrastructure exists, piped water is further purified to be suitable for human consumption such as drinking and using for cooking food as bulk of piped water is consumed for other purposes such as washing etc.

[0004] While pure drinking water is essential to good health of humans, our water resources are getting more and more polluted with pollutants and so a variety of water purification devices are being developed and marketed to meet the domestic as well as other drinking water requirements such as that of restaurants and hotels, public places etc. Reverse Osmosis (RO) water purification units are used widely nowadays for providing pure water for drinking and cooking.

[0005] Reverse Osmosis is a water purification technology that uses a semipermeable membrane to remove the larger dissolved particles of impurities from drinking water. In reverse osmosis, an applied pressure is used to overcome osmotic pressure, a colligative property (property of a solution that depends upon the ratio of the number of solute particles to the number of solvent molecules in the solution), which is driven by chemical potential. Reverse osmosis can remove many types of molecules and ions from solutions, as well as microbes including bacteria, and is commonly used in both industrial processes and the production of potable water. The result is that the solute is retained on the pressurized side of the membrane and the pure solvent is allowed to pass to the other side. To be "selective", this membrane should not allow large molecules or ions through the pores (holes), allowing only smaller components of the solution such as the solvent (water in our case) to pass freely.

[0006] A RO water filtration system generally comprises of a water source under pressure, a filter cartridge having a water inlet, a purified water outlet, and a discard water outlet and a purified water storage tank. The cartridge contains a semipermeable membrane, also known as a Nano-filter, for separating salts and other contaminants from the feed water. The incoming water may be pre filtered by other means, such as ultrafiltration or microfiltration to enhance life of the semipermeable membrane.

[0007] In accordance with the principle of Reverse Osmosis, feed water is fed to one side of the semipermeable membrane. The water molecules then permeate to the other side of the membrane under reverse pressure that overcomes the osmosis pressure, to provide pure filtered water. The feed water on feed side of the membrane is continuously replenished with fresh supply. Only a small amount of water gets filtered through the semipermeable membrane and the bulk of water supply is discarded.

[0008] Loss of major portion of water during RO filtration is a big disadvantage of such systems especially when discarded water cannot be put to any other use on account of dispersed installation of such systems as in domestic applications. Moreover, water shortage in many areas of the world has increased the need for judicious use of water resources. Social and environmental needs would be better served if wastage of water during RO filtration can be reduced.

[0009] There is therefore a need for a RO filtration system that can increase the yield of pure water from RO filtration units while reducing wastage of feed water, water being a precious natural resource.

[0010] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply. [0011] In some embodiments, the numbers expressing quantities of ingredients, properties such as concentration, reaction conditions, and so forth, used to describe and claim certain embodiments of the invention are to be understood as being modified in some instances by the term "about." Accordingly, in some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

[0012] As used in the description herein and throughout the claims that follow, the meaning of "a," "an," and "the" includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of "in" includes "in" and "on" unless the context clearly dictates otherwise.

[0013] The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. "such as") provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.

[0014] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. OBJECT OF THE INVENTION

[0015] An object of the present invention is to provide an RO based potable water system that can provide an improved yield of pure water from RO filtration units.

[0016] Another object of the present invention is to provide an RO based Potable water system that provides multi stage purification for providing potable water.

[0017] Another object of the present invention is to provide an RO based potable water system that reduces wastage of water - a precious natural resource.

[0018] Another object of the present invention is to provide an RO based potable water system that can provide potable water using water of different TDS (total dissolved solids) level.

[0019] An object of the present invention is to provide for a RO based potable water system that maintains required flow and appropriate pressure level of feed water at different stages so as to get high yield of pure water and minimize the risk of damage to the semipermeable membranes.

SUMMARY

[0020] The following presents a simplified summary of the disclosure in order to provide a basic understanding to the reader. This summary is not an extensive overview of the disclosure and it does not identify key/critical elements of the invention or delineate the scope of the invention. Its sole purpose is to present some concepts disclosed herein in a simplified form as a prelude to the more detailed description that is presented later.

[0021] Aspects of the present disclosure relate to a Reverse Osmosis system (RO) for water filtration. In an aspect, the disclosure provides a reverse osmosis potable water system with improved yield of potable water thereby reducing wastage of water.

[0022] An embodiment of the present disclosure provides a RO based potable water system that include a feed water inlet means configured to receive feed water, a first set of one or more filters configured in series to process the feed water to yield pre-treated feed water , a first RO unit configured to process the pre-treated feed water, a first pure water outlet to output pure water, a first reject water outlet, a piping unit configured with a non-return valve, wherein the piping unit is configured to supply the feed water to a junction point preceding the second RO unit where the pre-treated feed water is mixed with reject water from the first RO unit wherein the resultant mixed water is supplied to a second set of one or more filters and thereafter to a second RO unit configured to treat the mixed water. In an aspect, the piping unit is configured to maintain required flow and appropriate pressure level of the mixed water that is supplied to the second set of one or more filters so as to get a high yield of pure water and minimize the risk of damage to semipermeable membranes of the second RO unit.

[0023] In an embodiment, the first set of one or more filters and the second set of one or more filters can be any or combination of an antiscalent, water softeners, or scale inhibitor. In an exemplary embodiment, a mineral cartridge can be attached with each of the first pure water outlet and second pure water outlet, to add required minerals to the pure water to yield potable water. Potable water can thereafter be collected in a storage tank. In an embodiment, the disclosed RO based potable water system can comprise of two filtering units (referred to as RO unit hereinafter) configured with semipermeable membranes that can filter water based on reverse osmosis principle. In an aspect the two RO units can be configured in series such that reject water (also referred interchangeably as retentate) from the first RO unit can be fed, along with a stream of pre-treated feed water , as input to the second RO unit to get an additional yield of pure water and corresponding reduction in wastage of a precious natural resource i.e. water.

[0024] In an embodiment, the retentate from the first RO unit can be sent to the second RO unit through a control valve. Optionally an anti-fouling unit can also be configured in addition to the control valve. In an aspect the control valve can be configured to control the flow and maintain adequate back pressure on the feed side of the first RO unit wherein maintaining of adequate back pressure on the feed side of the first RO unit can ensure reverse osmosis pressure that is essential for adequate filtration from the first RO unit.

[0025] In an embodiment, the system can further comprise an additional pump (in addition to a first pump to feed water to the first RO unit) to feed the retentate from the first RO unit or the mixture of the retentate from the first RO unit and a stream of pre-treated feed water to the second RO unit. The additional pump can work to maintain reverse osmosis pressure in the second RO unit to facilitate filtration of water. As the reject water from the first RO unit may not meet the flow and operational pressure required for the second RO unit, and as the reject may also have high TDS level, the reject water from first RO unit can be mixed with a stream of pre- treated feed water , so as to maintain the required flow and provide appropriate pressure levels. Mixing the pre-treated feed water with reject water can also be controlled so as to reduce the TDS level of feed water fed to the second RO unit. In an exemplary embodiment, the reject water from the first RO unit can be processed by one or more of an antiscalent, water softeners, or scale inhibitor, so as to reduce the risk of early damage of the semipermeable membranes of second RO unit.

[0026] In an embodiment, the first set of one or more filters and the second set of one or more filters of RO based potable water purification system can include a sediment filter, an activated carbon filter and a microfiltration unit. The feed water can be received at inlet of the sediment filter and after filtering of sediments it can be sent to the activated carbon filter for removal of organic solvents present in water. A microfiltration unit can optionally filter output from the activated carbon filter before sending the pre-treated feed water to the first RO unit through the first pump.

[0027] In an embodiment, treated water obtained from the two RO units can be further treated with a mineral cartridge to replenish the water with essential minerals to yield potable water that can be collected in a storage tank.

[0028] Various objects, features, aspects and advantages of the inventive subject matter will become more apparent from the following detailed description of preferred embodiments, along with the accompanying drawing figures in which like numerals represent like components.

BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings are included to provide a further understanding of the present disclosure, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0030] FIG. 1A illustrates an exemplary schematic diagram of the disclosed RO based potable water system in accordance with embodiments of the present disclosure.

[0031] FIG. IB illustrates an exemplary schematic diagram of a RO based potable water system designed in accordance with an embodiment of the present disclosure.

[0032] FIG. 2 illustrates an exemplary RO based potable water system designed in accordance with an embodiment of the present disclosure. DETAILED DESCRIPTION

[0033] The following is a detailed description of embodiments of the disclosure depicted in the accompanying drawings. The embodiments are in such detail as to clearly communicate the disclosure. However, the amount of detail offered is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure as defined by the appended claims.

[0034] Each of the appended claims defines a separate invention, which for infringement purposes is recognized as including equivalents to the various elements or limitations specified in the claims. Depending on the context, all references below to the "invention" may in some cases refer to certain specific embodiments only. In other cases, it will be recognized that references to the "invention" will refer to subject matter recited in one or more, but not necessarily all, of the claims.

[0035] As used in the description herein and throughout the claims that follow, the meaning of "a," "an," and "the" includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of "in" includes "in" and "on" unless the context clearly dictates otherwise.

[0036] All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. "such as") provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.

[0037] Various terms as used herein are shown below. To the extent a term used in a claim is not defined below, it should be given the broadest definition persons in the pertinent art have given that term as reflected in printed publications and issued patents at the time of filing.

[0038] Aspects of the present disclosure relate to a Reverse Osmosis system (RO) for water filtration. In an aspect the disclosure provides a reverse osmosis based potable water system with improved yield of potable water thereby reducing wastage of water. [0039] An embodiment of the present disclosure provides a RO based potable water system that can include a feed water inlet means configured to receive feed water, a first set of one or more filters configured in series to process the feed water to yield pre-treated feed water, a first RO unit configured to process the pre-treated feed water, a first pure water outlet to output pure water, a first reject water outlet, a piping unit configured with a non- return valve, wherein the piping unit can be configured to supply the pre-treated feed water to a junction point preceding the second RO unit where the pre-treated feed water can be mixed with reject water from the first RO unit wherein the resultant mixed water can be supplied to a second set of one or more filters and thereafter to a second RO unit configured to treat the mixed water. In an aspect, the piping unit can be configured to maintain required flow and appropriate pressure level of the mixed water that can be supplied to the second set of one or more filters so as to get a high yield of pure water and minimize the risk of damage of membranes of the second RO unit.

[0040] In an embodiment, the first set of one or more filters and the second set of one or more filters can be any or combination of an antiscalent, water softeners, or scale inhibitor. In an exemplary embodiment, a mineral cartridge can be attached with each of the first pure water outlet and second pure water outlet, to add required minerals to the pure water to yield potable water. Potable water can thereafter be collected in a storage tank. In an embodiment, the disclosed RO based water purification system can comprise of two filtering units (referred to as RO unit hereinafter) configured with semipermeable membranes that can filter water based on reverse osmosis principle. In an aspect the two RO units can be configured in series such that retentate from the first RO unit can be fed, along with a stream of pre-treated feed water, as input to the second RO unit to get an additional yield of product water and corresponding reduction in wastage of a precious natural resource i.e. water.

[0041] In an embodiment, the retentate from the first RO unit can be sent to the second RO unit through a control valve. Optionally an anti-fouling unit can also be configured in addition to the control valve. In an aspect the control valve can be configured to control the flow and maintain adequate back pressure on the feed side of the first RO unit wherein maintaining of adequate back pressure on the feed side of the first RO unit can ensure reverse osmosis pressure that is essential for adequate filtration from the first RO unit.

[0042] In an embodiment, the system can further comprise an additional pump (in addition to a first pump to feed water to the first RO unit) to feed the retentate from the first RO unit or the mixture of the retentate from the first RO unit and a stream of pre-treated feed water to the second RO unit. The additional pump can work to maintain reverse osmosis pressure in the second RO unit to facilitate filtration of water. As the reject water from the first RO unit may not meet the flow and operational pressure required for the second RO unit, and as the reject may also have high TDS level, the reject water from first RO unit can be mixed with a stream of pre- treated feed water , so as to maintain the required flow and provide appropriate pressure levels. Mixing the pre-treated feed water with reject water can also be controlled so as to reduce the TDS level of feed water fed to the second RO unit. In an exemplary embodiment, the reject water from the first RO unit can be processed by one or more of an antiscalent, water softeners, or scale inhibitor, so as to reduce the risk of early damage of the semipermeable membrane of second RO unit.

[0043] In an embodiment, the first set of one or more filters and the second set of one or more filters of RO based potable water purification system can include a sediment filter, an activated carbon filter and a microfiltration unit. The feed water can be received at inlet of the sediment filter and after filtering of sediments, it can be sent to the activated carbon filter for removal of organic solvents present in water. The microfiltration unit can optionally filter output from the activated carbon filter before sending to the first RO unit through the first pump.

[0044] In an embodiment, treated pure water obtained from the two RO units can be passed through a mineral cartridge to replenish the water with essential minerals to yield potable water that can thereafter be collected in a storage tank.

[0045] Referring now to FIG. 1 A wherein an exemplary schematic diagram of a RO based potable water system 100 is illustrated. As shown, the RO based potable water purification system 100 can incorporate two RO units, a first RO unit 102 and a second RO unit 104. The two RO units, RO unit 102 and RO unitl04 can be configured in series such that the retentate, also referred interchangeably as reject water, from the first RO unit 102 is fed as input to the second RO unit 104. There can be a flow control valve 106 configured in the pipeline carrying the retentate from the first RO unit 102 to the second RO unit 104. Optionally an anti-fouling unit can also be used in addition to the control valve. In an aspect control valve 106 can be configured to control the flow and maintain adequate back pressure on feed side of first RO unit 102. In an aspect, maintaining of back pressure in the feed side of first RO unit 102 can ensure reverse osmosis pressure that is essential for adequate filtration from first RO unit 102. In an aspect, absence of a flow control valve 106 can result in need of installing a higher capacity pump such as 110, which supplies input water to the first RO unit 102. [0046] In an embodiment, the RO based potable water purification system 100 can further comprise a second pump 108 to feed the retentate from the first RO unit 102 to the second RO unit 104. The second pump 108 can work to maintain reverse osmosis pressure in the second RO unit 104 to facilitate filtration of water. There can be a second flow control valve 122 configured at the retentate outlet of the second RO unit 104. In an aspect the second flow control valve 122 configured at the retentate outlet of the second RO unit 104 can ensure back pressure in the second RO unit 104 to maintain reverse osmosis pressure.

[0047] In an exemplary embodiment, the proposed purification system can be complemented with adsorption unit, MF unit, anti-fouling unit and mineral dosing unit. In an embodiment, the RO based potable water purification system 100 can include a sediment filter 112, an activated carbon filter 114 and a microfiltration unit 116. The feed water can be received at inlet of the sediment filter 112 and after filtering of sediments it can be sent to the activated carbon filter 114 for removal of organic solvents present in water. Output from the activated carbon filter 114 can optionally be filtered by the microfiltration unit 116 before sending it to the first RO unit 102 through the first pump 110.

[0048] In an embodiment, pure water obtained from the two RO units 102 and 104 can be passed through a mineral cartridge 118 to add required minerals and yield potable water. Potable water can, thereafter, be collected in a storage tank 120.

[0049] FIG. IB illustrates an exemplary schematic diagram of the reverse osmosis based potable water system 150 designed in accordance with an embodiment of the present disclosure. As shown in FIG. IB, a water supply pipe unit 124 which can have a non-return valve 126, can be connected to supply the pre-treated feed water to a junction point where the reject water from the first RO unit 102 and the pre-treated feed water supplied through the pipe unit 124 can be mixed before supplying the mixed water to the second RO unit 104. In an exemplary embodiment, the reject water from first RO unit 102 can be mixed with the stream of pre-treated feed water through pipe unit 124 so as to maintain the required flow and provide appropriate pressure levels. As the reject water from the first RO unit 102 may not meet the flow and operational pressure required for the second RO unit 104, the water supply pipe unit 124 can be configured to mix the stream of pre-treated feed water with the reject water, before feeding the mixed water to the second RO unit 104. Mixing the pre-treated feed water with reject water also reduces the TDS level of feed water of second RO unit 104. In an exemplary embodiment, the reject water from the first RO unit 102 can be processed by one or more of a antiscalent, water softeners, or scale inhibitor, represented in FIG. IB as block 128, so as to reduce the risk of early damage to the semipermeable membrane of second RO unit 104.

[0050] FIG. 2 illustrates an exemplary RO based potable water system designed in accordance with an embodiment of the present disclosure. An embodiment of the present disclosure provides a RO based potable water system 200 that includes a feed water inlet means 202 configured to receive feed water, a first set of one or more filters, such as antiscalent 204, filter 206-1, filter 206-2, filter 206-3, UV disinfection unit 206-4, collectively and interchangeably referred as one or more filters 206, configured in series to process and partially treat the feed water and yield pre-treated feed water, a first RO unit 208 configured to process the pre-treated feed water, a first pure water outlet 212 to output pure water, a first reject water outlet, a piping unit 226 configured with a non-return valve attached with it that is configured to supply the pre-treated feed water to junction point 216 where this pre-treated feed water is mixed with reject water to supply the mixed water to a second set of one or more filters connected in series to partially treat the mixed water , a second RO unit 220 configured to treat the mixed water, and a second pure water outlet 228 to output pure water. The piping unit 226 is configured to to maintain required flow and appropriate pressure level of the mixed water being supplied to the second set of one or more filters and the second RO unit 220. Mixing the pre-treated feed water with reject water also reduces the TDS level of feed water of second RO unit 220. The RO based potable water system includes the piping unit 226 as a means to maintain required flow and appropriate pressure level of feed water to the second set of one or more filters and second RO unit 220, so as to get high yield of pure water and minimize risk of damage to semipermeable membranes of second RO unit 220.

[0051] In an embodiment, the first set of one or more filters 206 and second set of one or more filters can be any or combination of an antiscalant, water softeners, or scale inhibitor. In an exemplary embodiment, a mineral cartridge 214 can be attached with the first pure water outlet and second pure water outlet, to add required minerals to the pure water and yield potable water. Potable water can thereafter be collected in potable water storage tank 224.

[0052] In an alternative embodiment, the piping unit 226 can be configured to mix feed water that is filtered by one or more filters 206 with the reject water output of first RO unit 208 and to supply the mixed water to the second RO unit 220. In an exemplary embodiment, a pump 210 can attached with the system to supply pressurized pre-treated feed water to the first RO unit 208. Similarly, another pump 218 can be attached with the system to supply pressurized mixed water to the second RO unit 220. The second RO unit 220 can have a reject water outlet 222. In an embodiment, a UV disinfection unit 206-4 or similar other filters can be provided in the first set of filters to filter and kill pathogens before feeding water to the first RO unit 208.

[0053] In an embodiment, one or more filters 206 of the RO based potable water purification system 200 can be a sediment filter, an activated carbon filter and a microfiltration unit. The feed water can be received at inlet 202 of an antiscalant 204 that can treat the feed water and can send partially treated water to a sediment filter 206-1 that can filter sediments from it and can send it to the activated carbon filter 206-2 that can remove organic solvents present in it and send it to microfiltration unit 206-3 that can separate microorganisms and suspended particles from it. Output of the microfiltration unit 206-3 can be processed by one or more of ultra violet (UV) filters 206-4 or an ion exchange unit before sending the pre-treated feed water to the first RO unit 208 through first pump 210. In another embodiment, pure water obtained from the two RO units 208 and 220 can be passed through a mineral cartridge 214 to add required minerals. The system 200 can have one or more filters attached with the system for pre-treatment processes depending on the TDS level of feed water. The system 200 can be configured to provide high flow rate or low wastage of water for any kind of feed water including feed water with low to high total dissolved solids (TDS) level and feed water with low to high hardness.

[0054] As one may appreciate, the feed water to the first RO unit 208 is pre-treated by one or more filters using different pre-treatment procedures to yield pre-treated feed water that is supplied to the first RO unit 208. In alternative embodiments, the feed water can be pre-treated by one or combination of chemical coagulation, flocculation, clarification and/or gravity settling followed by multi-media filtration, or by means of prefiltration using microfiltration or ultrafiltration. In order to prevent formation of scale compounds on membrane of second RO unit 220, the reject water from the first RO unit 208 can be "softened" by suitable means in order to prevent scale formations.

[0055] In RO units, when pressurized feed water is supplied semipermeable membrane of the RO unit separates different inorganic ions and allows pure water to pass through the membrane. The inorganic ions can be any one or combination of as sodium, potassium, calcium, magnesium, iron, chloride, fluoride, carbonate, bicarbonate, sulphate and silica. The system 200 can include an ion exchange filter if feed water has high concentration of ions. In order to maintain an operating pressure higher than the osmotic pressure, the feed water can pass through a pump that can create required pressure and flow parameters of feed water for optimal filtration. An operating pressure higher than the osmotic pressure of the solution at RO unit 208 can be maintained by the first pump 210 in order to continue to permeate purified water through the membrane while allowing the membrane to retain/ separate / reject the soluble compounds. As the purified/cleaned water, also referred as permeate, coming out from the first RO unit 208 is low and the reject water coming out of the first RO unit 208 is high, the reject water can be reused. The reject water from the first RO unit 208 can be processed by the second RO unit 220 wherein to maintain the required pressure and flow parameters, the reject water from first RO unit 208 can be mixed with the pre-treated feed water supplied through the piping unit 226.

[0056] In an exemplary embodiment, the system can include acids and anti-scalants such as polyacrylates, EDTA, SHMP, etc. that can broaden the recovery range or the amount of purified water and improve life of the semipermeable membranes. The system 200 of the present disclosure provides high recovery rate and low wastage of water without increasing much the cost of the RO based potable water system. This is achieved by incorporating a first RO unit 208 and second RO unit 220 in series under adequate high pressure of feed water.

[0057] While the foregoing describes various embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof. The scope of the invention is determined by the claims that follow. The invention is not limited to the described embodiments, versions or examples, which are included to enable a person having ordinary skill in the art to make and use the invention when combined with information and knowledge available to the person having ordinary skill in the art.

ADVANTAGE OF THE INVENTION

[0058] The present invention provides an RO based potable water system that can provide increased yield of pure water from RO filtration units.

[0059] The present invention provides a RO based Potable water system that provides multi stage purification for providing potable water.

[0060] The present invention provides an RO based potable water system that reduces wastage of water - a precious natural resource. [0061] The present invention provides an RO based potable water system that can provide potable water for feed water of different TDS levels.

[0062] The present invention provides an RO based potable water system that includes means for maintaining required flow and appropriate pressure level of feed water at different stages so as to get high yield of pure water and minimize risk of damage to semipermeable membranes.

Claims

We Claim:

1. A reverse osmosis (RO) based potable water system with high recovery rate of pure water, the system comprising: a feed water inlet means configured to receive feed water; a first set of one or more filters, configured in series to partially treat the feed water; a first RO unit configured to receive pre-treated feed water supply from the first set of one or more filters, and process the pre-treated feed water with help of membrane(s) that rejects impurities present in the pre treated water and allows only pure water to pass through the membrane (s); a first pure water outlet configured to output pure water from the first RO unit; a first reject water outlet configured to output rejected water from the first RO unit; a junction configured to receive the rejected water from the first reject water outlet and a stream of pre-treated feed water through a piping unit configured with a non-return valve; a second RO unit configured to receive mixed water from junction point and process the mixed water with help of membrane(s) that allows only pure water to pass through the membrane and filters out different impurities present in the mixed water; a second pure water outlet configured to output pure water from the second RO unit; and a second reject water outlet configured to output reject water from the second RO unit.

2. The system of claim 1 , wherein the membrane(s) is a semi-permeable membrane or a nano- filter membrane.

3. The system of claim 1, further comprising a first pump configured to supply the partially treated feed water to the first RO unit at the high pressure side of the first RO unit with required pressure and flow parameters.

4. The system of claim 1, further comprising a second set of one or more filters preceding the second RO unit configured to pre-treat the mixed water from the junction point before supplying the mixed water to the second RO unit.

5. The system of claim 1 and 4, wherein the first set of one or more filters is one or combination of anti-scalant, a water softener, a scale inhibitor, means of pre-filtration comprising chemical coagulation, flocculation, clarification, gravity setting, multi media filtration, activated carbon, adsorption media, microfiltration and ultra-filtration.

6. The system of claim 1 and 4, wherein the second set of one or more filter is one or combination of an anti-scalant, water softener and scale inhibitor.

7. The system of claim 1, further comprising a second pump configured to supply the mixed water from the junction point to the second RO unit with required pressure and flow parameters.

8. The system of claim 1, wherein pure water from the first RO unit and pure water from the second RO unit passes through a mineral cartridge configured to add required minerals in the pure water.