RU2528989C2 - Water treatment water - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to water treatment device. Proposed device comprises at least two filter medium sized relative to each other so that ensure, first, saturation with filter medium to filter first contaminant and time-delayed saturation with filter medium to filter second contaminant.

EFFECT: lower costs treatment.

20 cl, 8 dwg

Description

This invention relates to a device for low-cost purification of drinking water and a sensor for warning the user when the water is no longer safe to drink. This low-cost device for water purification includes additional functionality that allows you to add beneficial impurities and molecules to water.

BACKGROUND OF THE INVENTION BACKGROUND OF THE INVENTION

Water purification devices can contain many different components that use different mechanisms to remove from water. One of the classes of water purification devices in accordance with the prior art is usually referred to as “on-site use” water purification devices (POUs). Such POUs are composed of components that remove impurities from the water at a relatively small scale, for example, this is a desktop-type device or a device oriented for apartment use, as opposed to a large central device like a municipal water treatment device.

POUs have generally been designed for the high-end market, i.e. a market where value-added POUs may be allowed. POUs did not penetrate efficiently into a large low-end market due to a lack of inventive designs in low cost areas.

A typical POU device may have a pre-filter to remove sediment, followed by nodes that remove pathogens and sometimes inorganic material. One of the most important features of a POU that contains consumables such as filters is the "end point" detection system, which alerts the user or maintenance staff that it is time to replace the filter. Most POU devices use a system with a time criterion in which, after a certain period of time has passed, a light (or other) indicator turns on, which signals that it is time to change the filter. This relatively inexpensive sensor is not adequate if the water purifier is used in different operating modes, and the required period of time between filter changes to avoid contamination can vary significantly, and, accordingly, there is a risk of users consuming contaminated water.

The main method for determining the composition (and safety) of water is to periodically take water samples and transfer these samples to a laboratory, where relatively large-sized equipment is used to analyze the composition of water. This information about what is in the water is sent back to the user or maintenance personnel. In addition, there are field kits that can test specific contaminants, such as chlorine. Typically, none of these standard test methods is versatile or compatible with a POU water purifier. Similarly, none of these test methods is convenient for the consumer.

Existing POU water purifiers do not add beneficial ingredients to water. Typical devices that transfer molecules or compounds into water are created in the confectionery industry or in the restaurant business. A saturator, for example, adds molecules and compounds that give a taste to sparkling water by simply mixing fluid streams, but does not add ingredients that are beneficial to the health of the consumer.

There is a need for an improved apparatus for purifying water and / or adding beneficial ingredients to water. The present invention attempts to satisfy this need.

SUMMARY OF THE INVENTION

In one aspect of the present invention, there is provided a water purification device comprising at least two filter media that are sized in relation to one another to allow first saturation of the first pollutant with some subsequent time delay before saturation of the second pollutant substance. In another aspect, there is provided a method for treating water, comprising passing water through a device comprising at least two filter media that are sized in relation to one another so as to initially saturate the first contaminant in water with some subsequent time delay before a second pollutant is saturated.

An important aspect of this device is the use by the user of the device as an endpoint detector for pathogens or other dangerous elements. This aspect of the device provides a basic principle in low-cost water treatment and maintaining water safety. The device of this invention uses the user as a detector through the vision or taste of the user. Some mechanism in a water purifier releases a colored element when the water filter reaches or begins to reach the end of its life. In addition, the device also has the ability to release various flavors into the water, which can also warn the user that the filter has reached the end of its life. In addition, since these determination mechanisms are introduced in a low cost manner, the same mechanisms can be used to transfer the desired molecules or compounds into purified water, thereby forming healthful drinks and / or therapeutic drinks.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic view of a first embodiment of the present invention, showing a low-cost device for cleaning arsenic;

FIG. 2 illustrates how a taste change medium breaks first and water will have an undesirable mold or earthy taste for a period of time delay before the water becomes contaminated with arsenic;

Figure 3 illustrates how time-delayed release capsules can release taste-changing substances that are absorbed by the downstream medium and saturate the medium at the appropriate time;

Figure 4 illustrates how time-delayed release capsules are designed in a sudden-release form, and they are then located at the end of the cleaning device;

Figure 5 illustrates time-delayed release capsules designed to deliver a uniform dose of flavor after a lapse of time;

6 illustrates a time-delayed release capsule designed so that its outer shell dissolves at such a rate that the flavoring substance is released as sharply as possible when the arsenic removal medium is near exhaustion; and

Figures 7 and 8 show the results of arsenic removal through a filter with a combination of activated carbon (AC) / granular iron oxide (GFO) for water from Lake Chapala over the life of the filter.

DETAILED DESCRIPTION OF THIS INVENTION

When referring to the drawings: FIG. 1 is a schematic view of a first embodiment of a low cost arsenic purification device of the present invention. The device 2 comprises a reservoir 4 for accommodating the water to be purified, connected through a valve 8 to a filtering region 10 having a sequence of correction media 12, 14, 16. Water passing through the filtering region 10 is discharged through the nozzle 18 by means of a valve 20 into a receiving reservoir 22 .

The pre-filter 12 is designed to remove large particles and sediment from the water. After the pre-filter 12 is a sequence of filter media that are designed to remove the target atoms, molecules or compounds from the water, and / or can be used to change the color or taste of the water when the medium is saturated with pollutants and the medium no longer purifies the water (t ie, this invention indicates that water will soon be unsafe), in the particular embodiment illustrated in FIG. 1, pre-filtering medium 12 is followed by a taste change medium 14 and a removal medium 16 arsenic.

Similar mechanisms can be used to introduce other beneficial compounds into water. Useful compounds may be, for example, vitamins, amino acids, minerals and / or herbal extracts. Some examples include vitamin A, vitamin C, vitamin D and vitamin E, vitamin K, vitamin B ₆ , vitamin B ₁₂ , thiamine, riboflavin, niacin, folic acid, biotin, pantothenic acid, calcium, iron, phosphorus, iodine, magnesium, zinc, selenium, copper, manganese, chromium, molybdenum, potassium, boron, nickel, silicon, tin, vanadium, lutein and lycopene.

The device of this invention is primarily designed to treat water that has been disinfected with chlorine. As indicated above, one of the correction media 14 may be designed to remove undesirable taste sensations, and the other medium 16 may be selected to remove arsenic.

Different geographical areas may have different problems with respect to water, and accordingly, regulation of the types of media, the number of media, or media ratios may be required in order to properly remove pollutants. The filter device is designed with the appropriate contact time of the free filter medium with water (EBCT) for each of the media to allow sufficient removal of the target contaminants. Typical EBCT values are in the order of 1 to 10 minutes, and these norms determine the flow of water through the volume of the filter medium.

The cleaning device may include additional filtering stages after the correction media described above (not shown). For example, a filter to remove fine particles (for example, a filter from wound fibers) and / or a filter to remove bacterial contaminants can be applied after steps with corrective media. Common components that cause problems with the taste of water are algal metabolites, such as geosmin or 2-methylisobornoleol (MIB), which give a moldy or earthy taste to water (See, for example, chapter 26 in Adsorption by Carbon, edited by Bottani and Tascon) . Although the arrangement of the medium in the device of this invention is not critical, in the embodiment illustrated in FIG. 1, the filter medium 14 for changing the taste is located immediately after the medium 12 for pre-filtration, followed by the medium 16 for removing arsenic.

In other embodiments, the media may be mixed, alternated, or stacked. In addition, although there are other potential media that can accomplish both of the tasks described above, activated carbon (also referred to as activated carbon) is usually selected as the filter medium 14 to change the taste, and one or more components of granular iron hydroxide , activated alumina, granular iron oxide, titanium oxide, zirconium oxide or other metal oxides, or a mixture of metal oxides can be selected as arsenic removal medium 16.

The design of the device according to this invention has a very low cost for two fundamental reasons. Firstly, the purpose of the device is two main problems that arise with water, namely the concentration of toxic arsenic and an undesirable taste. Secondly, the method for determining the end point is based on time or, more significantly, on taste. The device is able to use the user's taste as a mechanism for determining the endpoint by setting the dimensions of the medium for changing the taste and the medium for removing arsenic so that the medium for changing the taste is saturated before the medium for removing arsenic is saturated. When the volumes of these media are aged in size, as described, the taste-changing medium breaks through first and the water acquires an undesirable mold or earthy taste for a period of time before the water becomes contaminated with arsenic.

This effect is shown schematically in the circuit shown in FIG. 2. The task of the volume of medium in order to achieve this functional effect, in which the user is a sensor, since the user gives a signal to replace the medium when an earthy or moldy taste is detected in the water, is carried out in the sequence of steps described below.

First, local water characteristics are measured to determine the level of flavoring compounds, such as geosmin or 2-methylisobornoleol (MIB), and the level of arsenic in the water. Secondly, the environment for changing taste and arsenic removal is tested to determine how long it takes to saturate the medium with geosmin and / or 2-methylisobornoleol (MIB) or arsenic. After completion of the second step, volumes of medium in the device can be selected in order to achieve the effect shown in FIG.

For example, a two-component POU filter can be designed with activated carbon to improve the taste and granular iron oxide (GFO) to remove arsenic. By appropriately setting the dimensions of the medium, a change in taste acts as an early warning to the user that it is time to replace the filter. Relevant parameters are the adsorption capacity of the media in relation to the target pollutants, usually expressed in mg of pollutant adsorbed by a gram of medium. The adsorption capacity of activated carbon for 2-methylisoborneol (MIB) is in the range of 1 to 3 mg / g, depending on the structure of the activated carbon (starting material containing carbon, pore size and surface area distribution) and water chemistry (See e.g. chapter 26 in Adsorption by Carbon, edited by Bottani and Tascon, p.683, (2008)). Similarly, the adsorption capacity for arsenic (V) adsorption on granular iron oxide (GFO) is in the range of 0.5 to 1 mg / g depending on the chemistry of the water (Source: Adsorption Treatment Technologies for Arsenic Removal, AWWA publishing, Chapter 6, (2005)).

Suitable activated carbon can be obtained from Caigon Carbon Corporation (http://www.calgoncarbon.com/solutions/?view=ChallengeProducts&Industry=10&Application=7&Challenge=7). Granular iron oxide (GFO) can likewise be obtained from Severnt Trent Corporation (http://severntrentservices.com/Water_Wastewater_Treatment/Arsenic_Removal_prod_52.aspx).

For example, it is assumed that in water at the inlet, the concentrations of 2-methylisoborneol (MIB) and arsenic (V) are both 0.05 mg / L, and it is also assumed that the adsorption capacity for adsorption of both pollutants on the respective media for their removal is 1 mg / g Neither granular iron oxide (GFO) nor activated carbon (AC) has significant adsorption capacity with respect to another pollutant. Accordingly, to design a filter in which 2-methylisobornoleol (MIB) breaks through activated carbon before the arsenic breaks through granular iron oxide (GFO), a granular iron oxide (GFO) to carbon ratio of greater than 1 is required. A suitable ratio may be 2: 1 = mass of GFO: mass of activated carbon. This ratio will alert the user through an undesirable taste that it is time to replace the filter before the user is exposed to elevated levels of arsenic. Naturally, the total mass of the media (and, accordingly, the volume of the filter) should be selected in accordance with the estimated water flow rate and filter life. If the concentration of geosmin or 2-methylisoborneol (MIB) is not high enough, the saturation is not sharp enough, or the compound to give another suitable taste is not present in water, then the method described above cannot be used as a sensor to determine the end point.

If the flavoring compound is added at a constant flow rate from the outside of the POU device, the invention has the same design as shown in FIG. 1, since the taste removal medium of geosmin or 2-methylisobornoleol (MIB) is replaced with a medium that removes the intentionally introduced compound to give a taste. Alternatively, a flavoring substance or compound may be added within the POU device by the use of time-delayed release capsules.

FIG. 3 shows a device similar to that shown in FIG. 1, except that a region 24 is provided downstream of the flavoring medium 14 containing capsules that add flavoring agents at a constant release rate. These time-delayed release capsules can release taste-changing substances that are absorbed by the downstream medium and saturate the medium at the appropriate time (as shown in FIG. 3), or the capsules can be designed in a form of 26 with a sudden release , and they are located in this case at the end of the cleaning device as the last step (see Figure 4). In the first case (continuous), time-delayed release capsules (see FIG. 5) are designed to deliver a uniform dose of flavor after a lapse of time. In the case of the capsule shown in FIG. 6, it is designed so that its outer shell dissolves at such a rate that the flavoring substance is released as sharply as possible when the arsenic removal medium is near exhaustion.

The time-delayed release capsules of this invention used in the water purification device of this invention can also be used to release a coloring agent in addition to or instead of a flavoring agent. For example, both of the methods described above for releasing a flavoring agent can be used to release a coloring agent. In the first case, capsules with a release at a constant speed can be used to release a coloring substance that is absorbed by one of the media in the filter device, and saturation is planned so that the coloring compound reaches saturation in this medium immediately before the cleaning medium becomes saturated unwanted atoms, molecules or compound (s) to be removed. Accordingly, water will change color when it comes time to replace the cleaning medium. The time delay is designed in this device in such a way that, although the water changes color, the water is still safe for a certain period of time. The delay is designed by taking into account the degree of saturation of the coloring compound with the concentration released from the capsule with a time-delayed release, as well as saturation with the unwanted atoms, molecules or compound removed.

Time-delayed sudden release capsules can also be used to color the water to indicate that it is time to replace the cleaning medium. In this embodiment, the time-delayed outer shell of the capsule dissolves at such a rate that the colorant is released suddenly just before the cleaning medium is saturated with atoms, molecules or a compound that are removed from the water.

The time-delayed release capsules described herein are also useful for adding the desired atoms, molecules or compounds to water. Constant-rate release capsules described above are desirable for this beneficial release. Capsules are loaded into the medium or are located separately at the last stage of the water purification device (so that another medium does not remove the desired beneficial atoms, molecules or compounds). These capsules can release flavoring substances, as well as substances with a therapeutic effect, such as vitamins.

A key feature of this invention is the realization that the characteristics of the local water must be carefully evaluated in order to select the most suitable, least cost medium for optimal removal of arsenic at the point of use (POU) of water with a sufficient service life to receive drinking water in amount suitable for home use. For example, in one particular location, tests show that the chlorine content, arsenic valency and pH need to be taken into account primarily when choosing the most suitable arsenic removal medium. In the same way, the ratio of the media in the filter device should be adjusted based on the characteristics of the water and the desired service life and quality of the water after filtration. Neutralization of chlorine requires the use of activated carbon (AC), while the removal of arsenic requires a metal oxide medium such as granular iron oxide (GFO). In the example above, granular iron oxide (GFO) medium was selected because it exhibits excellent removal of As (V) at elevated pH values that occur when supplied with local water, compared to other metal oxide media such as activated alumina (Source: Adsorption Treatment Technologies for Arsenic Removal, AWWA publishing, Chapter 6, (2005)).

In order to minimize the plumbing work for making connections to the water supply and sewage systems and to reduce the assembly cost of the assembly, the media were combined in a single standard filter housing. It has been estimated that 550 g of granular iron oxide (GFO) (1.1 liters dry) can provide sufficient arsenic removal capacity with local water characteristics to achieve a design filter life of 7000 liters. The total filter volume was set equal to the volume of a standard filter element of 130 cm ³ in the POU device. It was determined that an element containing 1.1 L of granular iron oxide (GFO) and 1.1 L of activated carbon (AC) with a media ratio of 1: 1 by volume functions best for the conditions of this example.

After the process described above, the media ratios can be adjusted without undue experimentation, since the characteristics of the local water have already been determined. The media formed two separate layers, and water flowed through activated carbon (AC) before flowing through granular iron oxide (GFO). Figures 7 and 8 show the results of arsenic removal through a filter with a combination of activated carbon (AC) / granular iron oxide (GFO) for water from Lake Chapala over the life of the filter. The arsenic content was maintained below the limit of 0.01 mg / L during the test. In addition, chlorine was not found in the treated water, and the result was a taste that was pleasant to the locals. Depending on local water quality indicators, the size of the POU filter and the design operational life of the ratio of granular iron oxide (GFO) and activated carbon (AC) can be adjusted as needed. For the small filters available in POUs, it is expected that the appropriate ratios of granular iron oxide (GFO) arsenic removal medium to activated carbon would be approximately 1: 1 = volume of granular iron oxide (GFO): volume of activated carbon (AC) or more, for example 2: 1. These volumes should be adjusted taking into account the ability to remove arsenic and the densities of different media, suitable for the characteristics of local water. Additional media can be added to the filter elements to remove other water polluting substances when necessary, leading to elements with 3, 4 or more media components. Individual media may be separate (i.e., arranged in layers), as in the above example, or they may be mutually mixed.

Although this invention has been described in relation to what is currently considered the most practical and preferred embodiment, it should be understood that the invention is not limited to the described embodiment, but rather encompasses various modifications and equivalent devices included in the essence and the scope of the attached claims.

Claims (20)

1. A device for water purification, containing at least two filter media having such dimensions relative to each other so as to initially saturate the filter medium filtering the first pollutant in water, and with a time delay saturation of the filter medium filtering the second pollutant. 2. The device for water purification according to claim 1, which is an element of the system. 3. The water purification device according to claim 1, wherein said at least two filter media are located downstream of the water tank. 4. The water purification device according to claim 1, in which there is a preliminary filter downstream of the at least two filter media to remove coarse particles and sediment from the water. 5. The water purification device according to claim 1, which is configured to remove such contaminants as chlorine and arsenic. 6. The water purification device according to claim 1, wherein the first filter medium is activated carbon, when the first pollutant is chlorine, and the second filter medium is activated alumina, granular iron oxide and / or granular iron hydroxide, when the second pollutant is arsenic. 7. A device for water purification, containing
at least two filter media having such dimensions with respect to each other so as to initially ensure saturation of the filter medium filtering the first pollutant in water, and with a time delay, saturation of the filter medium filtering the second pollutant; and
delayed-release flavoring capsules to determine the end of the saturation of the filter medium. 8. The water purification device of claim 7, wherein the sustained release capsules are continuous release capsules. 9. The water purification device of claim 7, wherein the sustained release capsules are discontinuous release capsules. 10. The water purification device according to claim 9, in which the sustained release capsules are placed as the last stage of the device. 11. The water purification device of claim 8, in which the sustained release capsules are located upstream of the saturable filter medium and provide the introduction of a flavoring substance into the water. 12. A device for water purification, containing
at least two filter media having such dimensions with respect to each other so as to initially saturate the filter medium filtering the first pollutant in water and with a time delay saturation of the filter medium filtering the second pollutant;
sustained release capsules of a color-giving colorant to determine the end of the saturation of the filter medium. 13. The water purification device of claim 12, wherein the sustained release capsules of the coloring material are continuous release capsules. 14. The water purification device of claim 12, wherein the sustained release capsules are discontinuous release capsules. 15. The water purification device of claim 14, wherein the stepwise release capsules are the last stage of the device. 16. The device for water purification according to item 13, in which the capsules with continuous release are located upstream of the saturated medium and provide the introduction of a coloring substance into the water. 17. A device for water purification, containing
at least two filter media having such dimensions with respect to each other so as to initially ensure saturation of the filter medium filtering the first pollutant in water, and with a time delay, saturation of the filter medium filtering the second pollutant; and
sustained release capsules for continuous introduction into the water of a flavoring substance or substance with a therapeutic effect. 18. The water purification device according to claim 17, wherein the sustained release capsules are arranged so that the flavor is introduced into the water at the last stage of the device. 19. A method of water purification, according to which water is passed through a system containing at least two filter media having such dimensions with respect to each other so as to initially saturate the filter medium filtering the first pollutant in water and to delay the saturation of the filter medium filtering a second pollutant. 20. The method according to claim 19, according to which measurements of the characteristics of water are performed to determine the level of the content of flavoring compounds and the level of arsenic in the water; filtering medium is tested to determine how long it takes to saturate the medium with aromatic compounds and arsenic; and the volumes of media in the system are selected so as to initially ensure saturation with taste-giving compounds in water and with a time delay saturation with arsenic.

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