WO2016163868A1

WO2016163868A1 - Mixture, filter and method for removing arsenic, as well as a system and method, for producing drinking water

Info

Publication number: WO2016163868A1
Application number: PCT/MX2015/000059
Authority: WO
Inventors: Daniel DÁVALOS GÁLVEZ; Susana FLORES PRECIADO
Original assignee: Daflow S.A. De C.V.
Priority date: 2015-04-07
Filing date: 2015-04-07
Publication date: 2016-10-13
Also published as: MX2017002137A

Abstract

The invention relates to a chemical mixture for removing arsenic from water, formed by silica sand, iron with a purity of at least 97%, and brick dust. The invention also relates to a filter for removing arsenic from water, comprising a bed of a non-porous material, and a quantity of said chemical mixture. The invention further relates to a system for producing drinking water, characterised by comprising a filter for removing arsenic from water, of the type described in the preceding paragraph, a manganese dioxide filter, an activated carbon filter, and a zeolite filter. In addition, the invention relates to a method for removing arsenic from water, and a method for producing drinking water, as well as the water products resulting from said methods.

Description

MIX, FILTER AND METHOD, TO REMOVE ARSENIC; SYSTEM AND METHOD, TO OBTAIN DRINKING WATER

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a chemical mixture for removing arsenic from water; a filter for removing arsenic from water comprising said chemical mixture; a method to remove arsenic from water; thus also with a system to obtain useful water for the use of human consumption; and a method to obtain water useful for human use and consumption, which is free of arsenic.

BACKGROUND OF THE INVENTION The provision of water for human use and consumption with adequate quality is essential to prevent and prevent the transmission of gastrointestinal and other diseases, for which it is required to establish permissible limits in terms of their rnicrobioiotic, physical, organoleptic, chemical characteristics. and radioactive, in order to ensure and preserve water quality in the systems, until delivery to the consumer.

For such reasons, informal standards have been established for ta! purpose in order to establish an effective sanitary control of the water that is subjected to water treatment treatments in order to make it suitable for human use and consumption. An example of this is the Official Mexican Standard NO -127-SSA1- 1994 modified in 2000, whose objective and field of application is to establish the permissible limits of quality and treatment of water purification for human use and consumption, which is applicable to all public and private supply systems, and to any natural or moral person who distributes it, in the entire national territory. To meet such permissible limits, a number of technologies have been developed for the treatment of water intended for human use and consumption. For example, for the removal of water arsenic, Echeverría and Rodríguez (page 11), disclose that arsenic can be adsorbed on the surfaces of various adsorbents, such as: activated alumina, iron and other oxides, and natural adsorbents (bentonites, silicas, etc.), among which is the sial sand. However, it does not describe any indication of how to make a mixture with the components of a mixture for it {Echeverría,. and Rodríguez R. 2010. Arsenic removal through coagulation, filtration and sedimentation, comparison with available technologies and analysis of a type plant. Water Seminar p: 22). In a more specific aspect, patent document WO2008 / 127757 describes a filter for treating water, and which in turn contains an iron composition, comprising: an iron, manganese, cerium, carbon, phosphorus, sulfur, aluminum component , silicon, chromium, copper and zinc. As you can see, this mixture requires many ingredients, such as layers of sand, sand-coal, pieces of brick and / or sand-gravel, as well as a material! thin porous, such as nets, polyester fabrics, etc., to separate said layers from said mixture.

Said document WO2008 / 127757 also describes a filter where the iron composition described above can be used alone or between one or more layers of sand, sand-coal, pieces of sand-brick and / or sand-gravel; and each layer can be separated by a thin porous material, such as nets, polyester fabrics, etc. This iron composition can be placed in a desired container. The water product obtained had the following concentrations: aluminum <0.07 mg / L, arsenic <0.030 mg / L, iron <0.25 mg / L, manganese <0.22 mg / L, nitrites <0.07 mg / L, and pH 7.4 - 7.9 The use of zeoiites for water purification is described in WO2012034202, since said document discloses a method for removing organic chemicals and organometallic complexes {Cu, Ni, Cd, Co, Cr. Zn, Pb, Hg, Ag, Cs, Rb, Ba or Sr) of water containing diethientriamine (DETA) and DETA-heavy metal complexes, which comprises contacting these waters with zeoiites to absorb them.

On the other hand, Wirth (The magic of manganese dioxide: what it is and why it should matter to you; www.waterprodeveiopment.com) describes the use of manganese dioxide (nC * 2) in arsenic removal processes, specifically where it is Arsenic is co-precipitated with ether to Mn0 ₂ medium as ferric arsenate. In particular, it removes from the water ai iron, manganese and hydrogen suifide, As it has been observed, in the state of the art there is no configured tencnoiogy as the one proposed by the present invention for the arsenic remission of the water destined for the use and consumption of said liquid; In addition to the fact that the water product obtained by such known technologies, they hardly become within the upper permissible limit of the Standard. That is why a chemical mixture was developed to remove arsenic from water, a filter to remove arsenic comprising said chemical mixture, a system to obtain drinking water, a method to remove arsenic from water, a method to obtain water drinking water, and the purified water obtained by means of the mixture, the filter, the system and method referred to above. Because said filtered water obtained has amounts of arsenic other contaminants well below the permissible limits, it is useful for human use and consumption.

The details of the present invention are described below in a purely illustrative and non-limiting example, in the figures and description mentioned below. BRIEF DESCRIPTION OF THE FIGURES

Figure 1 is a conventional perspective view of the system for the treatment of water intended for consumption and use, of the present invention.

Figure 2 is a front view of the system for treating water intended for consumption and use, in question.

Figure 3 is a conventional perspective view of the quation system, where the filters have a longitudinal section to observe the internal arrangement of each of them.

Figure 4 is a top plan view of the system in question.

DETAILED DESCRIPTION OF THE INVENTION In the first instance, the present invention relates to a chemical mixture for the removal of arsenic from water, wherein said mixture comprises: static sand, Iron ai 97% purity, a! less; and brick dust.

In one embodiment of the present invention, the chemical mixture comprises syphilic sand in an amount of 20 to 40%; iron from 20 to 60%; and brick powder of 20 to 40%; with respect to the total volume of said mixture.

Moreover, a preferred embodiment of the mixture is when said mixture has the plastic sand in an amount of 35%; 35% iron and 30% brick dust, compared to the total volume! mix.

The granulometry of the brick powder can be from a granulometry of 8 to 100 mesh; and preferably 100. The way of preparing the mixture of the present invention is very simple, since it is sufficient to mix its ingredients by conventional means, from manual to mechanized means, depending on the amount of ingredients to be used. The invention also relates to a filter (2) for removing arsenic from water, wherein said filter comprises an amount of the chemical mixture (1) for removing arsenic from water, of the present invention; and a bed of a porous material (8) that serves as a support for the chemical mixture (1). Where said porous material (6) can be gravel on which the chemical mixture (1) is deposited. The amount of the chemical mixture (1) and the support material (6) will depend on! volume of water to be treated

AND! The filter containing the chemical mixture (2) can be of the covenconal filters that have the ability to backwash the filter material and have an upper and lower manifold, which allow an up and down flow, made of a material! resistant to oxidation and a pressure of about 2 kg / cm ² , Another aspect of the present invention is a system for obtaining arsenic-free drinking water, e! which is made up of an array of filters where the water passes for purification. Said filters are: at least one filter for removing arsenic (2) from water, such as the filter described in the present invention; to! less, a filter of manganese dioxide (3) to remove iron, manganese, and hydrogen sulfide, was connected with e! arsenic remover filter (2), so this filter has the same characteristics as the arsenic remover filter (2).

The system also comprises at least one activated carbon filter (4) as an organic detoxifier, to remove; Free Cl, Ozone, i, arsenic, Mercury, and Cr, in organic complexes, causing odor, taste and color, benzene, toluene, triatomethanes, organic pesticides, metiiene blue foam and dissolute oils). This filter is placed between e! Arsenic remover filter (2) and the Miter of manganese dioxide (3).

A zeoüta filter (5) is also provided as an expandable catalyst, which is located in the final part of the filter series, of! system in question. All containers of the filters can be of the same configuration of the arsenic remover filter container (2). A bed of a non-porous material (6), such as gravel, was applied to its internal base. , on which the filter material of each filter is placed; where the amount of the gravel (8) and the filter material will depend on the amount of the filter material to be supported.

The filters were connected to each other, by means of a pipe (7) for the flow of the water to be treated, where the pipe is configured so that the water passes through the filtering material, either by gravity or by a mechanical force.

Therefore, said system can be provided with a pump (not illustrated) to flow the water through the system in question.As will be understood, the system of the present invention is provided with means for collecting the water to be treated. , such as a container (8), which is connected to the filter that removes the arsenic (2), by means of the pipeline (7), as well as means for collecting the treated water, ready for be used and / or consumed; the means for collecting treated water can be a container (9), for example.

Another aspect of the invention is a method for removing arsenic from water, said method comprising: passing co-arsenic water through a chemical mixture to remove arsenic (1), as described in this invention, The mixture for removing arsenic (1) may be contained in a container, such as a filter, such that the water is passed at a pressure of 2 kg / cm ² . in a flow of 15 L / s, to cite an example.

A further aspect of the present invention is a method for obtaining arsenic-free drinking water, preferably; where the method includes, in addition to making happen to! water through the arsenic remover filter (2), pass it through the manganese dioxide filter (3), activated carbon filter (4) and «zeolite ro (5). Water enters the system at a pressure of 2 kg / cm ² , in a flow 15 L / s, going through the matter! filter of each filter. Where one modality is that the water enters through the upper part and out through the lower part of the filters involved, following the direction of the arrows in the figures. With this system and method, a water quality for human consumption is obtained, which meets the standards allowed by the Official Mexican Standard NO -127-SSA1-1994, modified on October 20, 2000. For this purpose, the comparison is made in the Table 3. Examples

The following examples are merely to demonstrate some of the embodiments of the present invention, so they should not be considered as a limitation for the present invention.

Example 1. System to obtain drinking water.

Two filters were used to remove the arsenic (2), whose container has the ability to backwash a filter material, with a sump and bottom collector that allowed an ascending and descending Rujo, made of a material resistant to oxidation and a pressure of 2 kg / cm ² ; whose dimensions were d 180.5 X 170.18 cm, a volume of 2.12 nr \ a flange of 15.24 cm, and with a tripod base. A 35% silica sand mixture was applied to said container; Iron at 97% purity, in an amount of 35%; and brick powder with a 100 mesh granulometry, in an amount of 30%, with respect to the total volume of the mixture.

Two filters of manganese dioxide (3) were included, to remove iron, manganese, and hydrogen sulfide, from water; This filter was connected with the arsenic remover filter (2), so the container of this filter has the same characteristics as the arsenic remover filter container (2). Two activated carbon filters (4) were included in the system of the present example, the four were connected to the manganese dioxide filters (3),

Two zeolite filters (5) were colored at the end of the series of the aforementioned filters.

The filters of the manganese dioxide (3), activated carbon (4) and zeolite (5) filters had exactly the same configuration as! arsenic remover filter container (2).

A first tinaco (8) was connected to the arsenic remover filter (2), to contain the water to be treated, where said water is not useful for use and consumption, because it has high amounts of non-permissible contaminants, such as arsenic, by example.

A second water tank (9) was connected to the zeolite filter (5), to receive the treated water, with a permissible content of arsenic and other contaminants, which is already useful to be used and / or consumed. A pipe (7) interconnected Sos filters (2, 3, 4 and 5) and the tinaco (8 and 9), in such a way that it allowed an upward and downward flow of the water to be treated.

An amount of 800 kg of gravel was applied to its internal filter to support the filter bed. To the arsenic remover filter (2) a quantity of the chemical mixture of 975 kg was put in total; to the manganese dioxide filter (3) 488 kg manganese oxide; 825 kg of activated carbon was applied to the activated carbon filter (4); and the zeolite filter (5) 575 kg of zeolite. The filters were placed vertically and linearly on the ground and communicated with each other by means of pipes (7) for the passage of the water to be treated.

With this system there was a water treatment capacity of 15 L s. Example 2. Method for the removal of arsenic from water, through the use of the arsenic remover filter of the present invention.

Water with arsenic, concentrated in a first water tank (8), was introduced into the filter to remove arsenic (2) of the present invention, at a pressure of 2 kg / cm ² , at a flow of 15 L / s, through the upper part of the filter (2); where the water crossed vertically the chemical mixture (1) and the gravel layer; and collect the water that comes out from the bottom of said filter (2), where said water leaves with a level of arsenic well below the permissible limits see results of the labia 2.

Example 3. Method for obtaining drinking water, by using the system of the present invention. Water with arsenic, concentrated in a first water tank (8), was introduced into the filter to remove arsenic (2) of the present invention, at a pressure of 2 kg / cm ² , in a flow of 15 L / s, through the upper part of the filter (2); where the water crossed vertically the chemical mixture (1) and the gravel layer; the water leaves the lower part of this filter, rises with the help of the pipe (7) and a pump (not shown), to make it enter the manganese dioxide filter (3) and so on with the other filters ; and finally, the water was collected in a second tinaco (9), where said resurgent water has a level of arsenic and other contaminants, well below the permissible limits see results in Table 3.

For backwashing, both of the system in question and of the arsenic removal filter (2), the pressure is increased by 0.5 Kg / cm ² , for this it will be enough to apply a water flow but in reverse, to the flow of the methods described above, so that the water releases pollutants from gravel and filter materials, which are channeled to the drainage, as it complies with Standard 003. Example 4. Analysis of water samples, prior to their filtering treatment, by means of the system of the present invention.

On June 18, 2013, water samples were collected from a system for filtration in the drinking water system, of the present invention. 8 samples of water to be treated were collected, which were stored in jars. ES water underwent a physicochemical analysis, atomic absorption, microbiology, among others, before filtering it with the system of the present invention, in the laboratory called "ECOTEC" of the company PIBSA, S. A de C. V .; whose results are concentrated in Table 1,

Table 1. Values of previous analyzes of water samples.

Bottle 1 Physicochemicals refrigerated 4 "C.

Test Value Units U Method

Residual Chlorine 2.02 mg / L1 +/- 9.2E-02 N X-AA-108- Free SCFI-2001

Chlorides (CI-) 22.4 mg / L1 + .8E-01 NMX-AA-073- SCFI-2001

Color <5.0 Pt-Co +/- NA MX-AA-045- SCFI-2001

Total hardness mg / L +/- 2.8E + 0Q N X-AA-072- (CaC0 ₃ ) SCFI-2001

Fluorides (F-) ___ mg / L +/- 1.7E-01 NMX-AA-077- ^"™

SCFI-200

Nitrites (N) <0.02 mg / L +/- N.A. NMX-AA-099- SCFI-2006

pH 6.81 pH +/- 1.0E-01 NMX ~ AA ~ 008- SCH-2011

Presence of iodine 0.11 mg / L +/- 5 E-03 NMX-AA-108- and Bromo SCFi-2001

Sulfates (S04-) 6.59 mg / L +/- 7.2E-01 N X-AA-074-

Bottle 2 Solids kept refrigerated 4 "C.

Bottle 3 Nitrogens conserved with: H _z S0 ₄ at pH <2 and refrigeration 4 ^* C

Bottle 6 Metals preserved with: HNO ₃ at pH <2 and refrigeration 4 ° C.

Aluminum 0.293 mg / L +/- 8.5E-03 N X-AA-051-

SCFS-2001

Barium <0.250 mg / L + / ^« NA N X-AA-051- SCFÍ-2001

Cadmium <0.000 mg / L +/- N N X-AA-051-

5 SQFI-2001

Copper <0.050 mg / L +/- N.A. N X-AA-051-

SCFI-2001

Total Chrome <0.001 mg / L +/- NA NMX-AA-051-

5 SCFI-2001

Iron <0.050 mg / L +/- N.A. N X-AA-051-

SCFI-2001 Manganese <Q.040 m4g / L +/- NA NMX-AA-051- SCFi-2001

Lead <0.005 mg / L +/- NA NMX ~ AA-05t ~

0 SCFi-2001

Sodium 86.6 mg / L +/- 4.2E + 0O NMX-AA-Q51- SCFí-2001

Zinc <0.020 mg / L +/- N X-AA-051-

SCFI-2001

Flask 7 Arsenic-Merci trio agreed with: h / V <¾ a ptt <; 2 and in cooling e

Arsenic 0.0729 mg / L +/- 37E-03 NMX-AA-051-

SCFt-2001

Mercury <0.0010 mg / L +/- NA, N X-AA-051-

SCFÍ-20Q1

Bottle $ Microbiological in sterile container kept refrigerated 4 ° C.

Fecal Coiiforms <2.0 NMP / 100 +/- A N X-AA-042- mi 1987

Total Cauliflowers <2.0 NMP / 100 +/- A NMX-AA-042- mi 1987 Example 5, Results obtained from water treated only by the arsenic remover filter (2), of the present invention,

In order to observe the efficiency of the arsenic remover filter of the present invention (2), on December 24, 2014, a sample of water filtered only by the arsenic remover filter (2) was analyzed in laboratories referred to as " Analysis of Water, S. A, of CV The results obtained are concentrated in Table 2.

As can be seen, in Table 2, the arsenic content is well below the permissible limits of the established Standard, so that said chemical mixture proposed in the present invention is highly competitive, despite being formulated with very few ingredients Table 2. Values of the water sample analysis after passing through the arsenic remover filter (2), according to the present invention.

P = Parameter, AA ~ Accredited or Approved Test, LDM ~ Method Detection Limit,

ND = Analytical Not Detected, NA «No App! LMP ~ Maximum Allowable Limit, AN = Code of the Analyst who performed the test, LPC - Practical Limit of Equation, U - Expanded Uncertainty = 2. * Contracted or subcontracted test, CF Fecal coliforms, CT = Total Coittermes.

Example 6. Comparative analysis of the water resulting from the system and

procedure, for obtaining potable water, of the present invention, against the permissible parameters established by the Official Mexican Standard.

As can be seen in Table 3, most of the water parameters resulting from the system and procedure of the present invention are well below the parameters established by the Official Ivlexicana Standard NOM-127-SSA1-1994 and also exceed the parameters reported in the prior art, for example with the parameters disclosed in patent document WO20Q8 / 127757. The chemical mixture of the invention gave a water product with 0.0026 mg / L on average arsenic, while the water product of WO2008 / 127757 was 0.030 mg / L which is a very high value, since the Standard Official has established in 2005, a concentration of arsenic d 0.025 rog / L. so that the water is consumable. So with the rest metals, the mixture in question gave better results compared to said WO2008 / 127757.

Table 3, Comparative parameters between water obtained by the system and method of the present invention, against the Official Mexican Standard

NOM-127-SSA1-19 4, modified in 2000.

* Analysis performed by ANASA (Analysis of Water, SA of C. V), on January 8, 2014, water samples from Nueva Galicia, Tíajomuíco de Zúñiga, Jalisco. It is worth mentioning that these examples are merely illustrative and not limiting, so that all those modalities or modifications, obvious to a person skilled in the art, fall within the scope of the present invention.

Claims

1. A chemical mixture to remove arsenic from water, characterized in that it comprises: i) syphilic sand;

i) iron in a purity of at least 97%; Y

tü) brick dust.

2. The mixture of the preceding claim, wherein the silica sand is in an amount of 20 to 40%; iron from 20 to 80%; and brick dust of 20 to 40%; with respect to the total volume of the mixture.

3. The mixture according to the preceding claim, wherein the sand is in an amount of 35%; 35% iron and 30% brick dust; preferably, with respect to the total volume of the mixture.

4. The mixture according to claim 1, wherein the brick powder has an 8 to 100 mesh granulometry.

5. The mixture of claim 1, wherein the mesh granulometry is 100, preferably.

6. A filter for removing arsenic from water, characterized in that it comprises: i) a bed of a non-porous material; Y

ii) an amount of a chemical mixture to remove arsenic from water is added to the gravel bed; wherein said chemical mixture comprises the characteristics of the chemical mixture according to any of the preceding claims.

7. The filter of the preceding claim, characterized in that it comprises a container configured to accommodate the bed of the non-porous material, the chemical mixture and allow the passage of water through the chemical mixture.

8. The filter according to claims 6 and 7, wherein the non-porous material is gravel.

9. A system for obtaining potable water, characterized in that it comprises an array of filters, as follows; at least one filter for removing arsenic from water, in accordance with claims 8 to 8.

at least one filter of manganese dioxide, to remove iron, manganese, and hydrogen sulfide;

at least one activated carbon filter, such as organic detoxifier, to eliminate free Cl, Ozone, i, arsenic, Mercury, and Cr, in organic complexes, causing odor, taste and color, benzene, toluene, trialomethanes, organic pesticides, Foam of methyrene blue and little oils); Y

At least, a zeolite filter as an expandable catalyst.

The system of the preceding claim, characterized in that the filters of manganese dioxide, activated carbon and zeolite, comprise a bed of a non-porous material, on which the filter materials are added.

11. The system according to claims 9 and 10, characterized in that each filter of manganese dioxide, activated carbon and zeolite comprises a container suitable for housing the bed of porous material, the filtering material and making the water flow through ! filter material

12. The system of claims 10 and 1 1. wherein the non-porous material is gravel.

13. The system according to claims 9 to fa 12, characterized in that it comprises a pipe for interconnecting the filters with each other.

14. The system according to claims 9 to 13, characterized in that it comprises at least a first water container that concentrates the water to be treated and is connected to the arsenic remover filter.

15. The system as claimed in claims 9 to ia 14, characterized in that it comprises a second container that concentrates the treated water.

16. The system according to claims 9 to 15, characterized in that it further comprises a pump for circulating water through the system.

17. A method for removing arsenic from water, characterized in that it comprises passing water with arsenic through a chemical mixture to remove arsenic, in accordance with claims 1 to 5,

18. A method for removing arsenic from water, characterized in that it comprises: passing water with arsenic through a filter for removing arsenic, in accordance with claims 6 to 8,

19. The method of the preceding claim, wherein the passage of water is done at a pressure of 2 kg / cm ² , in a flow of 15 L / s.

20. A method to obtain drinking water; characterized in that it comprises passing water with arsenic through the filters of the system in accordance with claims 9 to 16.

21. It is a method according to the preceding claim, where water enters the system at a pressure of 2 kg / cm ² , in a 15 Lis flow, through the filter material of each filter.

22. A water product obtained by the method for removing arsenic, according to any of claims 17 to 19, characterized in that said water product has an arsenic amount of 0.0026 to 0.0088 mg / L.

23. A water product obtained by the method for obtaining drinking water, according to claims 20 and 21, characterized in that said water product has the following amounts of: Aluminum <0.2000 mg / L, Arsenic 0.0026 mg / L , Iron <0.1000 mg / L, Mercury <0.0010 mg / L, Manganese 0.1080 mg / L, Sodium 94.2860 mg / L, Romo <0.0100 mg / L, fecal conformations 0 NMP / 100 mL, total coliforms 0

NMP / 100 mL, total hardness 162.00 mg / L, Fluorides 2,350 mg / L, Phenols <0.0100 mg / L, Ammoniacal nitrogen <0.5000 mg / L, Nitrites 0.0150 mg / L, Nitrates 1,082 mg / L, pleasant oior, pleasant taste , total dissolved solids 449,800 mg / L, Sulfates 9,580 mg / L, Total Trihalomethanes <0.032 mg / L, and pH 7.74.