TITLE OF THE INVENTION

"Single Core Multiple Fold Hybrid Membrane for Fluid Treatment"

FIELD OF THE INVENTION

The present invention relates to a purification device, more particularly to an integrated water treatment membrane and its efficient and automated operation, in providing sustainable purification system to improve the quality of treated water.

OBJECTIVE OF THE INVENTION

It is an objective of the present invention, to provide a new and improved membrane for purification of water that combines the efficiency of purification, based on the input quality of water.
It is another objective of the present invention to provide a membrane for purification, particularly a hybrid membrane for fluid purification which reduces the wastage as reject water within the purification system.
It is an objective of the present invention, to provide a new and improved single core hybrid membrane water purification system which combines the membranes such as Micro filtration, Reverse osmosis, Nano filtration, Ultra filtration and the combinations thereof.

It is another objective of the present invention to provide improved water purification systems which are simpler and more cost effective in design than conventional systems wherein the Total dissolved solids (TDS) of the output water is customised by the composition of the said single core multiple fold hybrid membrane.

RELEVANT PRIOR ART OF THE INVENTION

The membrane softening (MS) process and nanofiltration (NF) membranes are revolutionizing the soft water industry and moving water softening from a chemical-based to a largely membrane-based process. This change is evident at the municipal and industrial plant scales of application. The need for improvements in the water softening process at the residential level of application is no less, and no different, than that at the industrial level. The water utility industry is concerned about the cycle of water use (water conservation) and the chemicals added to hard water to convert it into soft water prior to use and disposal of the reject water. The predominant residential water treatment process used to soften municipal water is ion exchange. Membrane softening (MS) has been examined for residential use but not significantly adopted because of high water wastage. The MS process produces a de-mineralized permeate stream and a concentrate stream (also called a brine, reject or waste stream). These systems tend to produce more reject water or "Concentrate Water" in the ratio of 1:3, wherein 3 times of the input the water is rejected as reject water into the drain. The below relevant prior art documents addresses the use of reverse osmosis (RO) and nanofiltration (NF) membranes in water softening and water de-mineralization.

U.S. Pat. No. 5,501,798 (Al-Samadi) discloses a micro-filtration (MF)-enhanced industrial RO process for removing soluble and sparingly soluble inorganic salts from an aqueous solution. The method includes operating an RO membrane at a pressure in the range of 100 to 200 psig in excess of the membrane osmotic pressure. The method includes operating the RO membrane at a pressure in the range of 500 to 1000 psig to provide high system recovery of 90 percent or more. The process is illustrated with two configurations: (1) utilizing an RO membrane unit followed by a small capacity MF membrane unit, and (2) the use of a high capacity MF membrane situated upstream of the RO membrane unit. The maximum system recoveries are achieved with the use of anti-sealants, pH adjustment and other chemicals. The method further provides for controlled precipitation in a zone that does not adversely effect the RO membrane. Retentate is withdrawn at a rate of 50% to 500% of the rate of flow to the RO membrane chamber. A high rate of removal from the high-pressure side of the RO membrane is required to avoid precipitation on the membrane, and to avoid interference with its ability to operate at high efficiency. When it is not desirable to add chemicals to the water treatment system, precipitation can be made to occur on the high-pressure side by super-saturation and seeding or by heating of the retentate. The large recycle stream together with the need for chemical precipitation and the use of MF to separate the precipitate, results in high capital and operating costs. The industrial application of the process is limited and not very economical.
2. U.S. Pat. No. 5,925,255 (Mukhopadhyay) discloses a highly efficient industrial membrane process for removing hardness and non-hydroxide alkalinity from feed water to very low levels. The process achieves permeate recovery ratios of 90 percent or higher with most brackish feed waters, resulting in a substantial reduction in membrane cleaning frequency. The method is useful in the preparation of high purity water. The invention shows the feasibility of operating with high pH feed water while avoiding scaling of reverse osmosis (RO) membranes. The Langelier Saturation Index (LSI) in the final reject zone of the RO membrane unit is maintained in the negative range. For long run times, R is considered difficult to maintain recovery levels greater than approximately 75 percent and avoid carbonate scaling, unless a dissolving condition is produced in the RO reject water. The invention demonstrates that it is feasible to operate an RO-water treatment system at higher than pH 9, in a continuous, sustainable, long-term operation to produce ultra pure product water.

3.U.S. Pat. No. 6,103,125 (Kuepper) discloses several designs for a residential or commercial water desalination and softening system using a softening membrane element. The operation of the system is based upon the recycling and storage of rejected membrane concentrate. The rejected concentrate is mixed with source water for servicing 'other' (non-soft) water uses, and becomes the feed water for subsequent processing. The dynamics of water usage in a home or commercial building is used to periodically flush a re-circulation tank that supplies the elevated TDS water to the treatment membrane. Water for other purposes (flushing) is supplied with a deteriorated quality (increased TDS) as a result of the system operation. As soft water use is increased, the performance of the system deteriorates. The level of soft water use is considered for minimal drinking water requirements (about 2% of interior residential use); hot water use only (about 40% of interior use); selective hot and cold soft water (up to 70% of interior use); and for all water used in a building. With the higher levels of soft water production, it is necessary for the system to discharge substantial amounts of concentrate to the drain. The operating characteristics of the system are not disclosed.

4.U.S. Pat. No. 6,113,797 (Al-Samadi) discloses a two-stage high-pressure high-recovery process utilizing two reverse osmosis (RO) membrane systems. This invention provides for the economical industrial purification of water using a two-stage membrane process with a unique recycle of "softened" membrane concentrate streams. The first stage of the process involves the use of a low-pressure membrane system (normally operated at 200-400 psig) to pre-concentrate scale compounds while purifying the bulk volume of the scale-containing water (using anti-sealants and acid/alkali chemicals for pH adjustment). The first stage membrane system is followed by a second stage membrane system in which the concentrate from the first stage membrane system is treated further at higher pressure (500-3000 psig). The influent water is combined with a recycle stream of concentrate from the second stage process. The second stage is required in order to provide purification of the remaining pre-concentrated stream and to achieve very high overall water recoveries, (normally in the range 95-99 percent). Permeate recovery in the first stage is normally in the range 60-85 percent. Scale formation in the first and second stage membrane systems is prevented by the recycle of "softened" water containing a very low concentration of scale-forming compounds.

However, these documents do not address the need to reduce the amount of reject water from the water purification device. Hence it could be argued that individual customer demand for soft water should be met with a residential technology that matches industrial-scale efficiencies and capabilities, while also taking into account the reduction of reject water.

In view of the foregoing, there is a need for methods and apparatuses that provides a water purification device which provides sterilized water at the point of use and is environment friendly by reducing the water flow to the reject drain.

ABSTRACT OF THE INVENTION

The present invention relates to a composite filter for water purification and filtration. In particular, the present invention comprises a Single Core Multiple fold Hybrid Membrane for purification of water. The said single core multiple fold hybrid membrane comprises a combination of membranes such as Reverse osmosis membrane, Nano filtration membrane, ultra filtration membrane, micro filtrations and combinations thereof. In particular, the said hybrid Membrane of the present invention is a composite membrane for purification and filtration of water comprising a combination of (a) Reverse osmosis Membrane and (b) nanofiltration membrane and/or (c) Ultra filtration membrane and (d) a feed channel spacer. The said Single core Multiple fold Hybrid Membrane is formed by a Spiral wound module wherein, the basic unit is a sandwich of flat membrane sheets called a "leaf" wound around a central perforated tube. The said leaf consists of said combination of membrane sheets placed back to back or multiple independent folds and separated by the said feed channel spacer. In a preferred embodiment, there are multiple layers may be more than one, more than two or more than three and combinations of membranes thereof. The membrane combinations are customized based on the Total Dissolved Solids or Salts (TDS) of the Input water. The TDS of the water is the combined output TDS of the filtered water from the combination of the membranes used for purification. Furthermore, said membrane advantageously reduces the rejection of water as waste water, as it comprises a combination of membranes such as Reverse Osmosis and nano filtration to achieve the highest purity of water filtration.

BRIEF DESCRIPTION OF THE FIGURES

The embodiments herein will be better understood from the following detailed description with reference to the drawings, in which:

FIG. 1 illustrates a general block diagram of Single Core Multiple fold Hybrid Membrane, as disclosed in the embodiments herein;

FIG. 2 illustrates a general block diagram of triple membrane fold with non-uniform surface area to meet specific treatment as disclosed in the embodiments herein;

FIG. 3 illustrates a general block diagram of triple membrane fold with uniform surface area to meet specific treatment as disclosed in the embodiments herein;

DETAILED SPECIFICATION OF THE INVENTION

The embodiments herein and the various features and advantages, details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.

The present invention relates to a fluid purification system, more particularly a water purification system that comprises a single core multiple fold hybrid membrane for purification of water based on the input water. The said single core multiple fold hybrid membrane comprises a combination of membranes such as Reverse osmosis membrane, Nano filtration membrane, ultra filtration membrane, micro filtrations and combinations thereof.

Microfiltration (MF) membranes have the largest pore size of .1 microns, a molecular weight cut-off (MWCO) of greater than 1,000,000 daltons and a relatively low feed water operating pressure of approximately 100 to 400 kPa (15 to 60psi). Materials removed by MF include sand, silt, clays, Giardia lamblia and Crypotosporidium cysts, algae, and some bacterial species and typically large particles and various microorganisms.

Ultra filtration (UF) membranes with a pore size of .01 microns have smaller pores than MF membranes, an MWCO of approximately 10,000 to 100,000 daltons, and an operating pressure of approximately 200 to 700 kPa (30 to 100 psi) and, therefore, in addition to large particles and microorganisms, they can reject bacteria and soluble macromolecules such as proteins.

Nanofiltration (NF) membranes are relatively new and are sometimes called "loose" RO membranes with pore size of 0.001 microns, an MWCO of 1,000 to 100,000 daltons Operating pressures are usually near 600 kPa (90psi) and can be as high as 1,000 kPa (150psi). They are porous membranes,but since the pores are on the order often angstroms or less, they exhibit performance between that of RO and UF membranes.

Reverse osmosis (R.O.) membranes are effectively non-porous with pore size of 0.0001 microns and, therefore, exclude particles and even many low molar mass species such as salt ions, organics, etc.
The Single Core Multiple fold Hybrid Membrane is a composite membrane for purification and filtration of water comprising a combination of (a) Reverse osmosis Membrane and (b) nanofiltration membrane and/or (c) Ultra filtration membrane and a feed channel spacer.

The said Single core Multiple fold Hybrid Membrane is a formed by a Spiral wound module wherein, the basic unit is a sandwich of flat membrane sheets called a "leaf wound around a central perforated tube. The said leaf consists of said combination of membrane sheets placed back to back or independent folds of different types of membranes and separated by the said feed channel spacer. Layers of the leaf are glued along three edges, while the unglued edge is sealed around the perforated central tube. The filtered water in the permeate carrier travels spirally inward toward the central collector tube and is stored in a Storage tank of the purification system.

The said input water enters the said feed channel spacer at the end of the spiral-wound element in a path parallel to the central tube of the said Single Core Multiple fold Hybrid Membrane. As feed water flows through the spacers, a portion of the same permeates through either of the two said surrounding membrane layers and their combination thereof and into the permeate carrier, leaving behind any dissolved and particulate contaminates that are rejected by the Reverse osmosis membrane and/or nano filtration and /or ultra filtration membranes.

The membrane herein disclosed in the invention is a combination of Reverse osmosis membrane and/or nano filtration membrane and /or Ultra filtration membrane and/or micro filtration membrane. The said combinations are customized based on the input TDS quality of the water. The said reverse Osmosis membrane purification purifies water with high TDS with approximately 90-99 percent TDS reduction. The said nano filtration membrane purification purifies water with high TDS with approximately 60-70 percent TDS reduction. The said ultra filtration membrane purification purifies water with Zero TDS reduction
In a typical example, the tables below illustrate the membrane element TDS reductions for Uniform and non uniform surface area of the said Single Core Multiple Fold Hybrid Membrane for Fluid Treatment.

Table I: Membrane element with Reverse Osmosis and Nano filtration membrane with Uniform Surface area: In a preferred embodiment, the single core membrane comprises a multiple fold hybrid membrane, wherein the Spiral wound module is fold with one or more combinations of membrane, selected from a combination of membranes such as Reverse osmosis membrane, Nano filtration membrane, ultra filtration membrane, micro filtrations and combinations thereof.

In one of the preferred embodiment, the spiral would is fold with a Reverse Osmosis membrane and/or nanofiltration module separated by the said feed channel spacer. The second layer of the multiple layers is ultra filtration module and/or micro filtration module separated by the said feed channel spacer. Similarly, the multiple fold hybrid membrane comprises of number of layers as customised for the TDS of the input water.

While the filtered water in the permeate carrier travels spirally inward toward the central collector tube, the water in the feed spacer that does not permeate through the membrane continues to flow across the membrane surface, becoming increasingly concentrated with rejected contaminates.

The accumulated solids are removed from the systems by flushing and/or are allowed to accumulate wherein the solids reduce the flow to an unacceptable level, at which point the membrane cartridge is replaced. The said system can also utilize a periodic "backpulse" or a short interval of reverse flow (which may include air and/or addition of small doses of oxidants) designed to dislodge particles from the membrane surface of the system. This process re-suspends particles, effectively concentrating the suspended solids in the feed near the membrane surface and increasing the potential for pathogens or other particulate to pass through an integrity breach and contaminate the filtrate.

The said Single Core Multiple fold Hybrid Membrane advantageously reduces the rejection of water as waste water, as it comprises a combination of membranes such as Reverse Osmosis and nano filtration to achieve the highest purity of water filtration. It avoids the use and/or dependency of purification by reverse Osmosis as a single membrane filtration where in the reject water is three times more for the same amount of purified water.

The said device comprises the said Single Core Multiple fold Hybrid Membrane is eco-friendly and provides a reduced wastage of water during the purification system.

The purification system of the present invention, though not specifically described for operation in any particular applications, is used in domestic, industrial or the like for customized purification of water based on the TDS of the input water.

Claims

1. A single core multiple fold hybrid membrane for purification of water, comprises hybrid layers of combination of membranes for purification wound around a feed channel, wherein the membrane interacts with the dissolved chemicals in the water resulting in the removal of both organic /inorganic chemical constituents during filtration.

2. The single core multiple fold hybrid membrane of claim 1 wherein the membrane is selected from the group comprising of Reverse osmosis membrane, Nano filtration membrane, ultra filtration membrane, micro filtration membrane or the like.

3. The single core multiple fold hybrid membrane of claim 1, where in the combination of membrane sheets are selected on the Total Dissolved Solids or Salts (TDS) of the input water.

4. The single core multiple fold hybrid membrane of claim 1, where in the combination of membrane sheets are placed back to back or independent folded form at varied propositions around the feed channel based on the need of said TDS rejection requirements.

5. The combination of single core multiple fold hybrid membrane of claim 4, is selected from, Reverse Osmosis membrane and Nano filtration membrane; Nano filtration membrane and Ultra filtration membrane; Ultra filtration membrane and Reverse Osmosis membrane; Reverse Osmosis membrane and Microfiltration membrane; Microfiltration membrane and Nano filtration membrane; Microfiltration membrane and Ultra filtration membrane; and combinations thereof

6. The single core multiple fold hybrid membrane of claim 1, where in the combination of membrane sheets are selected based on the TDS of the source water to be purified and provides treated water with different TDS than purified with a single filtration Membranes

7. A method for purification and filtration of water containing chemical constituents which comprises: (a) Selecting the combination of membrane based on the input and output TDS of the water (b) providing the selected single core multiple fold hybrid membrane combination which interact with the organic/ inorganic chemical constituents in the,,water resulting in removal of the chemical constituents and (c) filtering the water containing the organic/inorganic matter through the membrane to obtain different TDS than with a single filtration membrane

8. A method for purification and filtration of water containing chemical constituents which comprises: (a) providing in a purification apparatus which comprises single core multiple fold hybrid membrane combination; and (b) filtering the water containing the organic/inorganic constituents through single core multiple fold hybrid membrane combination, resulting in the removal of the organic/inorganic matter by the filtration; and (c) removing the purified and filtered water and, stored in the purification apparatus with different TDS than with a single filtration membrane.