The present invention relates to water purification process and, in particular, to home based reverses osmosis drinking water purification process, which would enable avoiding the limitation of reverse osmosis process as regards total demineralization of the purified water. Importantly, the reverse osmosis purification process of the invention is-, directed for improved and wide scale use/application of reverse osmosis in purification of water maintaining desired selective levels of mineral content. The process of the invention is directed to serve as a simple and cost effective manner of fortifying reverse osmosis treated water with desired natural mineral content for use in providing safe and healthy drinking water.

BACKGROUND ART

It is well known to follow reverse osmosis process for generating purified water. In particular, usually a reverse osmosis drinking water process involves inlet and outlet pipes such that the raw water is led into the reverse osmosis treatment zone whereby the reverse osmosis divides the water into pure water and waste water. While the wastewater is 'drained out, the pure water is guided into a storage container.

US 5,928,503 disclose a reverse osmosis mechanism consisting of a reverse osmosis filter and a pair of active carbon filters. The reverse osmosis mechanism is linked to a pump through an inlet pipe, a pure water pipe connected to a reservoir and an outlet pipe connected to the original reservoir where both pipes link the original reservoir to the pump. A water level sensor in the reservoir is linked with the pump through a processor to control a water pumping operation. When the water level rises above the water level sensor, the pump is initiated and delivers water from the reservoir into the reverse osmosis mechanism. Pure water then flows into the storage tank and wastewater flows to the reservoir. When the volume of the water in the reservoir is approximately one-third of the volume of the original water maintained in the reservoir, the pump is deactivated. At this time, the purified water contained in the storage tank approximates two-thirds of the volume of the water in the reservoir, which provides for an increased purifying rate.

US 6,120,688 discloses a method of purifying impure water to provide drinking water using an apparatus, the method comprising the steps of providing a micro filtration unit, a reverse osmosis unit and a CIP (clean-in-place) tank containing retentate interconnected to permit back flushing the micro filtration filter with retentate and continued or uninterrupted operation of the reverse osmosis unit by directing retentate thereto.

^■ US 6,579,451 teaches the provision of a water desalting installation which comprises at least an auxiliary pump and another high pressure pump in parallel with an internal circulation pump, and at least one pair of feed chamber which are pressurized alternatively, each of them forming a closed circuit, preferably toroidal, so that the water circulates always in the same direction and continuously, taking advantage of its kinetic energy in the valve actuation; it may have separation means to separate the water masses of different salinity, said separation means being comprised of pistons having a spherical shape and of which the apparent density is similar to that of the water, said pistons being retained briefly during the cycle change by baskets or equivalent devices, while the water circulates to the expense of its kinetic energy, the cycle changes being controlled by approximation and housing sensors, or by flow meters or by salinity measures when such separation means are not available.

It is found by way of present invention that while reverse osmosis continue to serve as an effective means for purification of water such as for drinking water purposes and the like, the purified water generated by such reverse osmosis treatment is usually found to be deficient in essential natural mineral content which is required by the human body. Importantly, it is found that although reverse osmosis is successful and it is commonly used for purifying water having high salt content and also achieve excellent, result in removing bacteria, viruses as well as salts from tap/tube well water, use of such reverse osmosis process essentially lead to removal of essential minerals from raw water required by the human body.

Again contaminants such as bacteria and viruses are known to be removed by way of conventional filtration means such as UF membranes and/or UV lamp sources.

US 6,395,182 discloses a method for purifying water, in particular ground water, under anaerobic conditions, using a membrane filtration unit, wherein the following steps are carried out: 1) connecting the membrane filtration unit to a rinsing unit then 2) passing a rinsing agent from the rinsing unit through the membrane filtration unit so as to create anaerobic conditions in the membrane filtration unit and 3) passing the water to be purified through the membrane filtration unit , in which anaerobic conditions have thus been created in step 2), wherein the connection between the membrane filtration unit and the rinsing unit is then shut off so that the anaerobic conditions in the membrane filtration unit obtained in step 2) are maintained while the water to be purified is passed through said membrane filtration unit .

US 6,447,721 discloses an ultraviolet (UV) disinfection system and method for treating fluids including a configuration and design to function effectively with at least one UV light source or lamp that is not submerged in the fluid. The UV light source is positioned outside the fluid to be disinfected via exposure to at least one UV dose zone outside the fluid being treated wherein UV light is projected into the at least one dose zone. The UV light source may be presented in a vertical riser configuration, wherein the UV light source is positioned above the fluid to be treated and projecting a UV dose zone downward toward and into the fluid to be treated, with the fluid moving upward toward the UV light source. Alternatively, the UV light source may be presented in a non-vertical riser configuration, wherein the UV light source is positioned above the fluid stored at least temporarily within a reservoir and projecting a UV dose zone downward toward and into the static fluid to be treated, arid is particularly effective where the fluid is pre-treated or purified drinking water.

Thus while the above state of art reveals the possible advantageous use of reverse osmosis in removing high salt content as well as bacteria and viruses and also whi|e methods involving UF/UV for removing bacteria/viruses is also known, it is found by way of the invention that the method of water purification based on reverse osmosis are not capable of generating good quality safe and healthy drinking water due to complete demineralization of the purified water. Importantly while the above process of reverse osmosis presently in use can purify water by removal of high salt content _f the reverse osmosis is found to be disadvantageous due to its substantial aηd

complete demineralization of the processed water. As discussed above natural mineral is required by human body from drinking water and in case of such complete demineralization following reverse osmosis, the purified water is necessarily not healthy and safe enough for the human body. Also while various methods have been proposed in the art such as involving the use of UF membrane or UV lamp to remove harmful bacteria/viruses as contaminants from drinking water, such methods on its own are again not capable of carrying out the effective desalting of the water possible by way of reverse osmosis.

OBJECTS OF THE INVENTION

It is thus the basic object of the present invention to provide for a process for reverse osmosis based purification of water which would avoid the afore discussed limitation/drawbacks in terms of complete and substantial demineralization of reverse osmosis treated water.

Yet another object of the present invention is to provide ot reverse osmosis based drinking water, which would enable providing metered and controlled incorporation of natural mineral useful for the human body in demineralised purified drinking water generated following reverse osmosis.

Yet another object of the present invention is directed to a simple and cost effective manner of providing reverse osmosis based drinking water, which would enable providing metered and controlled incorporation of natural mineral useful for the human body in purified drinking water.

Yet another object of. the present invention is directed to ensure safety and guard against health concerns due to limitations resulting from complete demineralization of reverse osmosis treatment for purified drinking water and enable reverse osmosis method for providing drinking water with desired levels of natural mineral content.

Yet further object of the present invention is directed to providing for reverse osmosis based method of purification of water which would be simple and enable incorporating desired levels of essential natural mineral in drinking water thereby

providing for wide scale safe and effective application and use of reverse osmosis in water purification ensuring safety and well being of individual.

SUMMARY OF THE INVENTION

Thus according to the basjc aspect of the present invention there is provided a drinking water purification process for producing purified water with controlled natural mineral content comprising:

Subjecting reverse osmosis treated demineralised water ' to at least a step of controlled natural mineral incorporation to thereby provide for purified drinking water with controlled natural mineral content.

According to an aspect of the present invention there is provided a drinking water purification process comprising:

(a) demineralization of raw water by reverse osmosis process;

(b) providing partially purified water having desired mineral content,'

(c) mixing the said demineralised reverse osmosis treated water with said partially purified mineral containing water; and

(d) purifying the mix of (c) above by passing through further filtration stages.

ϊn accordance with an embodiment the said drinking water purification process comprises:

(a) demineralizing of raw water by reverse osmosis process;

(b) providing partially purified water having desired mineral content ¹ ;

(C) mixing the said demineralised reverse osmosis treated water with said partially purified mineral containing water; and

(d) purifying the mix of (c) above by passing through further filtration stages such as to free the water of harmful bacteria and viruses.

In accordance with another aspect of the present invention there is provided a drinking water purification process comprising: 10

(a) demineralization of raw '"water by reverse osmosis process;

(b) providing raw water processed by passing through further filtration stages such as to free the water of harmful bacteria and viruses and having desired mineral

15 containing water.

(c) mixing the said demineralised reverse osmosis treated water with said raw processed and desired mineral containing water.

20 Preferably, in the above process the said step of providing raw water processed and having desired mineral content comprise stages for removal and/or killing of harmful bacteria and viruses. Also, in the above process it is also possible to carry out the step of controlling the TDS level in purified water.

25 It is thus possible by way of the above discussed reverse osmosis based method of water purification to fortify usually demineralised purified water generated by reverse osmosis with desired levels of natural mineral content and safeguard agatrisf ^' the drawbacks/limitation of complete demineralization of water following presently available reverse osmosis based purification.

30. .

Advantageously the method of reverse osmosis based purification of the invention not only provides for natural mineral content in purified water but also provides for the much required flexibility and control over the mineral content in drinking water. Importantly, the process provides for controlled TDS levels in purified water, which

is directed to take care of the much-desired health attributes concerning constitution of purified water generated By reverse osmosis processes.

The above method of the invention for the first time provides for regulating the mineral content in purified water following reverse osmosis based purification. The method is simple and cost effective and is directed to facilitate wide scale application and use of the reverse osmosis technique for purification of drinking water avoiding the concern of complete demineralization of water following such reverse osmosis system.

The selective provision of flow control step in the above process by way of controlling the flow of the purified water with mineral content would enable effectively regulating the contents in the purified water depending upon the end user requirements/specifications, The method is therefore directed to add value to the process of reverse osmosis for purification of water in particular in drinking water and can be selectively combined with other conventional methods of treatments of water to lead to good quality and desired mineral containing purified water. Statement of Invention: Accordingly the present invention provides a reverse osmosis based drinking water purification process for producing purified water with controlled natural mineral content comprising:

<a) Demineralization of raw water by reverse osmosis process;

(ti) Subjecting reverse osmosis treated demineralised water to atleast a step of controlled natural mineral incorporation in a manner as herein described; (c) Optionally purifying.-rthe water obtained in step (b) above by passing through further filtration stages to obtain purified and fortified with natural mineral content water.

The details of the invention, its objects and advantages are explained hereunder in greater detail in relation to non-limiting exemplary illustrations as per the following examples.

EXAMPLES EXAMPLE I

Under this example raw water was subjected to desalting technique involving the conventional reverse osmosis process. For the purpose the constitution of the raw water before and after its passage through the reverse osmosis membrane was noted especially in terms of its salt, mineral and harmful bacteria/virus contents and the results are represented in the Table I on the following page: Table I

EXAMPLE II

Under this Example raw water was subjected to UF membrane and UV lamp treatment and the constitution of the raw water before and after its treatment was noted especially in terms of its salt, mineral and harmful bacteria/virus contents and the results are represented in the Table II hereunder:

Table II

It would be clearly apparent from the above results that the same confirms the findings of the present invention that while reverse osmosis provides for desalting of the raw water the same in the process also removes the essential minerals required in purified and healthy drinking water. On the other hand the treatment involving UF membrane and UV lamp while providing for the removal of harmful bacteria and viruses is unable to relieve the water of the unnecessary salt content and

contamination by way of excessive salt in purified water continue to affect the desired purity of drinking water.

Thus the above results bring out the limitations of the conventional methods of reverse osmosis and /or the UF or UV lamp treatment and requires for a filtration and purification method involving reverse osmosis whereby the water purified is not only pure but is also healthy and would contain the desired levels of mineral content which is essential to the body.

EXAMPLE III

Under this example a reverse osmosis method for purification of the water in accordance with the present invention involving a selective controlled incorporation of essential mineral in reverse osmosis treated water in accordance with the present invention is carried out.

For the purpose, raw water is first subjected to reverse osmosis and thereafter the constitution of the processed water in terms of its salt, mineral and harmful bacteria/virus contents was determined.

Thereafter, based on the required end use and the desired levels of mineral required in the water controlled amount of UF membrane/UF lamp treated water containing desired mineral is introduced into the reverse osmosis treated demineralised water to provide for the purified salt-free but controlled mineral containing purified water.

The stages of demineralization under reverse osmosis followed by mineral addition subsequently directed to meet the desired controlled levels of mineral in reverse osmosis treated water is detailed hereunder in Table III:

Table III

It would be clearly apparent from Table III above that it is possible by way of the method of the invention to advantageously avoid the prior art limitations of the reverse osmosis treatment of water considering the total removal of health essential minerals from drinking water and provide for reverse osmosis purified drinking water which can have controlled amount of selective content of mineral apart from being harmful bacteria/virus free.

It is thus possible by way of the present invention to provide for a process for reverse osmosis based purification of water, which would avoid the limitation/drawbacks in terms of complete and substantial demineralization of reverse osmosis treated water. Also by way of the above method of the invention the generation of reverse osmosis based drinking water, would enable providing metered and controlled incorporation of natural mineral useful for the human body.

The method of the invention is directed to a simple and cost effective manner of providing reverse osmosis based drinking water, which would enable providing metered and controlled incorporation of natural mineral useful for the human body in purified drinking water. The invention is thus directed to providing for wide scale safe and effective application and use of reverse osmosis in water purification ensuring safety and well being of individual.