FORM 2
THE PATENTS ACT, 1970 (39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10, rule 13)
1. Title of the invention:
DEVICE FOR PURIFICATION OF WATER
2.. Applicant(s)
NAME NATIONALITY ADDRESS
TATA CONSULTANCY SERVICES Indian Nirmal Building, 9th Floor, Nariman Point,
LIMITED Mumbai, Maharashtra-400021, India
3. Preamble to the description
COMPLETE SPECIFICATION
The following specification particularly describes the invention and the manner in which it
is to be performed.

TECHNICAL FIELD
[0001] The present subject matter relates, in general, to a device for purification
of water and, in particular, to a device for removing fluorine ions from drinking water obtained from ground and surface water sources.
BACKGROUND
[0002] Water available from natural sources, such as groundwater sources, or surface water sources, has impurities. The impurities may include chemical impurities, such as fluoride and arsenic, and biological impurities, such as Escherichia coli, and can cause acute and chronic illnesses. Fluoride, for example, occurs in both surface water and groundwater in varying concentrations.
[0003] Excessive exposure to fluoride can give rise to a number of adverse effects. These range from mild dental fluorosis to crippling skeletal fluorosis as the level
and period of exposure increases. Various health organizations have prescribed safe limits for fluoride concentration in drinking water. For example, the World Health Organization (WHO) prescribes a value of 1.5 parts-per-millon (ppm) as the safe limit for fluoride concentration in drinking water.
[0004] The prescribed safe limits for fluoride concentration in drinking water often tend to be difficult to achieve. A large population across the world, especially those in developing and underdeveloped countries, directly consumes contaminated water. Elevated fluoride concentrations usually occur in contaminated water, thus, subjecting the consumers depending on contaminated water to the effects of fluorosis. Defluoridation plants may be set up for providing purified water for the population, but such plants usually get abandoned due to lack of proper maintenance. Further, point-of- use or household defluoridation devices that are available in the market are expensive and involve regular maintenance, which puts them beyond the reach of many households.
SUMMARY
[0005] This summary is provided to introduce concepts related to a device for purification of water, which is further described below in the detailed description. This summary is not intended to identify essential features of the claimed subject matter nor is it intended for use in determining or limiting the scope of the claimed subject matter.

[0006] In an embodiment, a device for purification of water includes a dosing unit to provide at least one chemical to the contaminated water, resulting in formation of floc water having flocs. The flocs include a portion of contaminant ions removed from the contaminated water. The device also includes a treatment unit having a floc separator to provide floc-free water by removing the flocs from the floc water, where the floc water is received from the dosing unit under an influence of gravity. An adsorber selectively adsorbs a substantial portion of remaining contaminant ions from the floc-free water to provide purified water. BRIEF DESCRIPTION OF DRAWINGS
[0007] The detailed description is provided with reference to the accompanying
figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to reference like features and components.
[0008] Fig. 1 illustrates an exemplary water purification device, according to an
embodiment of the present subject matter.
[0009] Fig. 2 illustrates an exemplary dosing unit of the water purification device, in accordance with an embodiment of the present subject matter.
[0010] Figs. 3(a) and 3(b) illustrate exemplary operation of measuring units of
the dosing unit, in accordance with an embodiment of the present subject matter.
[0011] Fig. 4 illustrates an exemplary construction of a stirrer unit of the water
purification device, in accordance with an embodiment of the present subject matter.
[0012] Fig. 5 illustrates the constructional details of a treatment unit, in accordance with an embodiment of the present subject matter.
DETAILED DESCRIPTION
[0013] Devices and methods for purification of water are described herein. The
devices and methods facilitate removal of ions, for example, fluoride and arsenic ions, from water. Fluorine (F") ions occur in both surface water, having concentrations ranging from 0.01 parts-per-million (ppm) to 0.3 ppm, and groundwater, with concentrations varying from about less than 1 ppm to about more than 35 ppm. It is well known that excessive exposure to fluoride can adversely affect human's health by causing illnesses such as dental fluorosis and skeletal fluorosis. Various health organizations such as World Health Organization (WHO), United States Environmental Protection Agency

(USEPA), and Bureau of Indian Standards (BIS) have prescribed safe limits for fluoride concentration in drinking water. For example, WHO prescribes a value of 1.5 ppm as the safe limit for fluoride concentration in drinking water.
[0014] The prescribed safe limits for fluoride concentration are often difficult to
achieve, especially in rural areas. A large population across the world, especially in the rural areas in developing and underdeveloped countries, directly consumes contaminated water. Various systems or methods are implemented to provide purified water to the population, either at community level or for households. However, such systems or methods, typically, are expensive and involve frequent maintenance, which puts them beyond the reach of many households.
[0015] Conventionally, techniques such as reverse osmosis and membrane technology are implemented to reduce fluoride concentration in contaminated water. However, both the techniques require electrical energy input, which may either be unavailable or be in short supply in rural areas of developing or underdeveloped countries. Furthermore, systems implementing such techniques are usually costly and, thus, beyond the reach of rural population.
[0016] Other conventional systems implement contact precipitation for fluoride removal from contaminated water. In such systems, calcium and phosphate compounds are added to contaminated water, and then brought in contact with an already saturated bone charcoal medium. Precipitation of calcium fluoride and fluorapatite is catalyzed in a contact bed of saturated bone charcoal that also acts as a filter for the precipitates. These systems can be used as a domestic unit as well as in a community plant. However, such systems require skilled installation of fittings and careful adjustment of flow rates. Furthermore, such systems have limited durability and the fluorides break through after saturation of the bed. This defluoridation method is unreliable and unsafe to be used in households.
[0017] Other conventional techniques, such as the Nalgonda technique or mechanisms based on adsorption of fluoride using activated alumina, are often difficult to maintain. The Nalgonda technique, for example, releases the fluorine ions back to water. Additionally, sulphate concentrations are relatively high in the water after treatment. Further, disposal of produced toxic sludge, which also contains fluorine ions,

may have adverse effects on the environment. Mechanisms based on activated alumina produce wastes containing fluorine ions.
[0018] The present subject matter describes a device for purification of water, also referred to as a water purification device. The water purification device selectively removes fluorides from water, for example, water for consumption or further use. In an embodiment, the water purification device includes a dosing unit, a stirrer unit, and a treatment unit. The dosing unit adds pre-determinable amounts of one or more chemicals to the contaminated water. A stirrer unit of the water purification system is then used to uniformly mix the chemicals with the contaminated water. The mixing of chemicals in the contaminated water leads to flocculation followed by precipitation. Flocculation is a process in which colloids come out of suspension in the form of floc or flakes whereas in precipitation, a dissolved solute, in a solution of at least one solute and at least one solvent, due to certain chemical reaction forms an insoluble compound which comes out of the solution as a precipitate. Thus, in one implementation, the mixing results in floc formation. The floc complexes with fluoride ions present in the contaminated water to form floc water.
[0019] After a prescribed wait-time, the floc water is passed through the treatment unit under the influence of gravity. The treatment unit performs water
purification in two stages. In the first stage, the floc water passes through a series of floc
separators. The floc separators physically retain the flocs as well as any particulate
matter present in the floc water and pass floc-free water through a bank of adsorbers. The
adsorbers selectively adsorb fluorides from the floc-free water, which further reduces
fluorides and other ions, to provide purified water. The purified water then flows into a
collection container from where the purified water can be used for consumption.
[0020] The water purification device, as described herein, keeps fluoride concentration in water below the safe limits throughout its rated life, within wide ranges of input fluoride concentration and water pH level, and total dissolved solids (TDS) conditions. Additionally, the device described herein may also be used to remove other contaminant ions such as arsenic ions, microbial contaminants, etc. The water purification device can be effectively employed as a household or community level purification device, does not require electricity, is cost effective, is easy to operate, and requires minimal maintenance.

[0021] These and other features of the present subject matter are explained hereinafter with reference to embodiments illustrated in the drawings. It would be appreciated that no limitation of the scope of the subject matter is thereby intended and it would be understood by those skilled in the art that the foregoing description is exemplary and explanatory of the specific embodiments and are not intended to be restrictive thereof. Further, even though the description is in terms of fluorides; however, other contaminants can also be removed by certain variations as will be understood by a person skilled in the art.
[0022] Fig. 1 illustrates an exemplary water purification device 100, interchangeably referred to as device 100, according to an embodiment of the present
subject matter. In said embodiment, the device 100 includes a source container 102 and a
collection container 104. The source container 102 can be of any suitable capacity,
volumetric or any other measure, depending upon the need, for example, the source
container 102 may have a capacity to hold 10 litres of water. Similarly, the collection
container 104 can be of any suitable capacity, say 10 litres. Additionally, the source
container 102 and the collection container 104 maybe of different capacity.
[0023] In an embodiment, the source container 102 receives contaminated water, indicated by an arrow marked 106. The contaminated water 106 may be obtained from any source of water, such as ground water and other surface water sources, and therefore may have chemical and microbial contaminants. Further, the contaminated water 106 may be supplied to the source container 102 either in batches of a suitable quantity, say 5 litres, at regular intervals, say every 1 hour, depending upon the purification and consumption rates, or in a continuous manner with the influx rate adjusted according to the purification and the consumption rates.
[0024] The device 100 further includes a first dosing unit 110-1 and a second dosing unit 110-2, collectively referred to as dosing unit 110, which add pre-determined quantities of chemicals (as indicated by arrows A and B) to the contaminated water 106. In one implementation, the chemicals may include at least one of a metal salt solution and an alkali solution. In an example, the concentration of the metal salt solution is within I to 1000 parts per million (ppm) and the concentration of the alkali solution is kept in the range of about 0.001 to 100 ppm. However, other concentrations may also be used as will be understood by a person skilled in the art.

[0025] Within the source container 102, a stirrer unit 114 thoroughly mixes the chemicals with the contaminated water 106 such that chemical reactions occur between the chemicals and the contaminated water 106. The chemical reactions lead to formation of a complex chemical compound with the contaminants, for example fluorides, present in the contaminated water 106. Such a complex chemical compound agglomerates to form floc. The contaminated water 106 containing floc is hereinafter referred to as floc water. The floc water gravitatively passes at a suitable flow rate; say 5 litres per hour, into a treatment unit 116. The flow rate may be adjusted using any known flow regulating mechanism, such as a valve or a nozzle 117.
[0026] Further, in one embodiment, the treatment unit 116 employs a two-stage process for removal of contaminants, such as fluoride, from the floc water. In the first stage, the fluorides are removed by flocculation while in the second stage; further reduction of fluoride is accomplished by adsorbing the remnant fluoride on a chemically treated medium. As indicated by arrows, the water passes from one stage to another within the treatment unit 116 under the influence of gravity. The water obtained after substantial removal of impurities, such as fluorides and turbidity, is referred to as purified water 118 and can be withdrawn from the collection container 110 for consumption or further use through a tap 120.
[0027] The source container 102, the collection container 104, the dosing unit 110, the stirrer unit 114, and the treatment unit 116 may be made of a material including, but not limited to, Polyethylene (PE), polypropylene (PP), acrylonitrile butadiene styrene (ABS), polycarbonate (PC), polyethylene terepthalate (PET), low density polyethylene (LDPE), high density polyethylene (HDPE), polystyrene, polyvinyl chloride (PVC), polytetrafiuoroethylene (PTFE), nylons, polyesters, acrylics, polyolefins, polyurethanes, polyamides, polycarboxyamides, phenolics, polylactic acids, rubbers, and combinations thereof. The operation and construction of the various components of the device 100 is further described in detail with respect to Figs. 2 to 5.
[0028] Fig. 2 illustrates construction of the exemplary first dosing unit 110-1 and
the second dosing unit 110-2 of the water purification device 100, according to an embodiment of the present subject matter. In one implementation, the water purification device 100 includes the first dosing unit 110-1 and a second dosing unit 110-2, collectively referred to as dosing unit 110, for dosing different kinds of liquid chemicals.

For example, the first dosing unit 110-1 may be used for dosing a metallic salt solution and the second dosing unit 110-2 may be used for dosing an alkali solution. Examples of the metal salt include aluminium acetate, alurninium chloride, aluminium hydroxide, aluminium sulphate, alumimum nitrate, alumimum carbonate, ferric bromide, ferrous carbonate, ferrous chloride, ferrous hydroxide, ferrous sulphate, ferrous oxalate, ferric sulphate, ferric chloride, and combinations thereof. In one embodiment, the metal salt is aluminium sulphate. Alkali used in combination with aluminium salt can be potassium hydroxide, sodium hydroxide or any other base of alkali and alkali earth metals. Even though the description hereinafter is with reference to multiple dosing units, however, it will be understood that a single dosing unit may also be used.
[0029] Further, in one implementation, the first dosing unit 110-1 consists of a first chamber 202-1, a first casing 204-1, and a first measuring unit 206-1. Similarly, the second dosing unit 110-2 consists of a second chamber 202-2, a second casing 204-2, and a second measuring unit 206-2. The first chamber 202-1 and the second chamber 202-2 are collectively referred to as chambers 202. The first and the second measuring units 206-1 and 206-2 are collectively referred to as measuring units 206. The chambers 202 store liquid chemicals to be dosed to the contaminated water 106. In said embodiment, each of the chambers 202 is kept in an inverted position within the casing 204. For example, the first chamber 202-1 is kept in the first casing 204-1 and the second chamber 202-2 is kept in the second casing 204-2.
[0030] Further, to provide metered volumes of chemicals into the contaminated water 106, the first chamber 202-1 is connected to the first measuring unit 206-1 through the first casing 204-1, while the second chamber is associated with the second measuring unit 206-2 through the second casing 204-2. When a chamber, for example, the first chamber 202-1, is connected to a measuring unit, for example, the first measuring unit 206-1, the chemical flows from the first chamber 202-1 to the first casing 204-1. A breather 208-1 in the first chamber 202-1 helps in maintaining a constant level of the chemical in the first casing 204-1. Similarly, another breather 208-2 in the second chamber 202-2 helps in maintaining a constant level of the chemical in the second casing 204-2. The chemical also fills the first measuring unit 206-1 or the second measuring unit 206-2, as the case may be. The first measuring unit 206-1 and the second measuring unit 206-2, which are in the form of tubes, dose chemicals to the water through openings 210-1 and 210-2, respectively. The openings 210-1 and 210-2 are collectively referred to

as opening 210. In said embodiment, the volume of the chemical filled in the first measuring unit 206-1 or the second measuring unit 206-2 is equal to the volume of the chemical desired to be mixed with the contaminated water 106 and is considered as a single dose of the chemical.
[0031] Thus, the first measuring unit 206-1 adds pre-determined quantity, for example, in a range of about 0.5 milliliter to 2 milliliter, of a chemical from the first chamber 202-1 to the contaminated water 106. Similarly, the second measuring unit 206-2 also adds desired quantity of a chemical into the contaminated water 106 stored in the source container 102 (as shown in Fig. 1). The operation of the measuring units 206-1 or 206-2 is further described with reference to Figs. 3(a) and 3(b).
[0032] Figs. 3(a) and 3(b) illustrate exemplary operation of a dosing unit, for example dosing unit 110-1, in accordance with an embodiment of the present subject matter. As shown in Fig. 3(a), when a chamber, for example, the first chamber 202-1, is connected to a casing, for example, the first casing 204-1, the chemical flows from the first chamber 202-1 to the first casing 204-1. As mentioned before, the breather 208-1 in the first chamber 202-1 helps in maintaining a constant level 304 of the chemical in the first casing 204-1. The chemical also fills the measuring unit 206-1, which is in the form of a tube, through the opening 210-1 to the level 304.
[0033] Once the chemical is obtained in the first measuring unit 206-1, a single dose of the chemical is discharged by pressing down the first measuring unit 206-1 to a
position D from a position C, as shown in Fig. 3(b). As a result, the chemical in the first
measuring unit 206-1 enters the source container 102 through the opening 210-1. To
reset the first measuring unit 206-1, the first measuring unit 206-1 is pulled back to the
position C. This can be done either manually, coupled with the float in the source
container 102 or through an electronic arrangement as will be understood to a person
skilled in the art. When the first measuring unit 206-1 comes back at the position C, the
chemical from the first casing 204-1 re-fills the first measuring unit 206-1. For this, the
same amount of the chemical from the first chamber 202-1 enters the first casing 204-1
so as to maintain the constant level 304 of chemical in the first casing 204-1.
[0034] Fig. 4 illustrates an exemplary construction of the stirrer unit 114 of the water purification device 100 located within the source container 102, in accordance with an embodiment of the present subject matter. In said embodiment, the stirrer unit 114

includes a controller 402 and a plurality of blades 404. A shaft 406 connects the blades
404 to the controller 402. In one implementation, the controller 402 controls the
operation of the blades 404 and makes the blades 404 rotate in different directions. The
shaft 406 and the blades 404 move in unison on activation by the controller 402.
[0035] In operation, when the controller 402 is activated, the stirrer unit 114
moves in a direction, say clockwise direction. As a result, the chemicals get thoroughly mixed with the contaminated water 106. The controller 402 can also be operated to rotate in the opposite direction, i.e., in the anti-clockwise direction, thus returning the stirrer unit 114 to its initial state. This is referred to as one cycle of the stirrer unit 114. In one implementation, one cycle is sufficient for thorough mixing of the chemicals with the contaminated water 106. However additional rotation(s) or cycle(s) may be used as desired.
[0036] Due to mixing of the chemicals in the stirrer unit 114, reactions between
the chemicals occur. Consider a scenario in which the dosing unit 110 provides sodium hydroxide and aluminum sulphate. The two react in a predefined wait time, for example 10 minutes, to give aluminium hydroxide according to chemical reaction (1): Al2{SO4)3 +6NaOH → Al(OH)3 +3Na2SO4
[0037] The aluminium hydroxide Al(OH)3 thus formed complexes with fluorides present in the contaminated water and flocculates according to chemical reaction (2) in the pre-defined time: Al(OH)3(floc)+ F→ Al(OH)3F- (complex)

[0038] The floc water thus produced is then sent for purification. Flow rate of the floc water may be adjusted using any known flow regulating mechanism, such as a valve
or a nozzle 117. For example, when the valve 117 is opened, the floc water flows from
the source container 102 to the treatment unit 116 for purification. The construction and
operation of the treatment unit 116 is described in the following paragraphs.
[0039] Fig. 5 illustrates the constructional details of the treatment unit 116, in
accordance with an embodiment of the present subject matter. In one embodiment, the treatment unit 116 includes a bank of floc separators, for example floc separators 502-1, 502-2,..., 502-4 (collectively referred to as floc separators) 502), followed by a bank of

adsorbers, for example adsorbers 504-1, 504-2,..., 504-4 (collectively referred to as adsorber(s) 504). Each floc separator 502 is made of a porous cloth material made from a fabric; mesh or foam made out of a suitable material including, but not limited to, cotton, canvas, felt, nylon, polypropylene, polyamide polyester, polyvinylalcohol, and combinations thereof. The material used can be produced using suitable process for example, weaving, spinning, spun bound, melt brown, and needle punched processes and may be formed either in a woven or non-woven manner.
[0040] In operation, the floc water from the source container 102 is made to pass
through the floc separators 502 under the influence of gravity. The flox separators 502 have small pores on their surfaces. The floc in the floc water, along with other particulate matter, gets retained within the floc separators 502 along with the fluoride in the range of about 50% to 90% of total fluoride in the contaminated water 106. Not all the fluorides are adsorbed on the aluminum hydroxide floc and some fluoride passes into the floc-free water 506 gravitatively exiting the floc separators 502. The amount of the fluorides passing through the floc separators 502 depends on the pH of the reaction and the amount of floc generated.
[0041] In one embodiment, the concentration of fluoride in the floc-free water, indicated by an arrow marked 506, is further reduced by passing the floc-free water 506 through the adsorbers 504. In said embodiment, the adsorber 504 is a cylindrical vessel filled with an adsorption media 508, for example, aluminum hydroxide coated with rice husk ash, activated alumina, bone char, ferric hydroxide coated with rice husk ash, and any combination thereof. In one example, the adsorption media 508 comprising aluminium hydroxide coated rice husk ash may be made using any known method. In one method, rice husk is cleaned and sieved to a size range of about 425 microns to about 800 microns. The rice husk ash is then coated with aluminium hydroxide. The aluminium hydroxide coated rice husk ash is dried at a specific temperature in the range of about 80°C to 120°C for a period of about 5 to about 8 hours. Other adsorbent media may be prepared using known methods.
[0042] Further, in one implementation, the adsorption media 508 becomes selective to fluorides around neutral pH levels, for example, in the range of pH 6.5 and 7.5. Hence, the functioning of the adsorber 504 is not affected by the presence of other ions, such as sulphate, nitrate, chloride, carbonates, and bicarbonates, which are usually

present in high concentrations in water, for example, drinking water, available from ground and surface water sources.
[0043J The operation of the adsorber 504 can be further understood with the help
of an example. Reference is made to Fig. 5, which shows an exploded view of one of the
adsorbers 504, i.e., the adsorber 504-1. As shown, the floc-free water 506 enters into the
adsorber 504-1 through a curved surface 510 and then flows to a centre of the adsorber
504-1. Such a radial flow of the floc-free water 506 through the adsorber 504-1 leads to
the adsorption of the remnant fluoride and other ions present in the floc-free water 506
with the adsorption media 508. The water coming from an outlet port 512, i.e., the
purified water 118, is substantially free from fluorides and other contaminants such as
As+3 and As+5 ions. The purified water 118 from the adsorber 504-1 collects into the
collection container 104 (as shown in Fig.l) and can be withdrawn for consumption.
[0001] The water purification device, as described herein, keeps fluoride
concentrations in water below the safe limits throughout its rated life and within wide ranges of input fluoride concentration, water pH level and total dissolved solids (TDS) limits. The water purification device can be effectively employed as a household or community level purification device, does not require electricity, is cost effective, is easy to operate, and requires minimal maintenance. The cost-effective and readily available chemicals further make the device more cost-effective. Hence, the water purification device is affordable for households with low income level, such as rural households in developing and underdeveloped countries. Besides, the water purification device is also capable of reducing concentration of other contaminants such as heavy metals, pathogenic micro-organisms, harmful ions, etc. The removal of contaminants is not dependent on the oxidation state of the contaminants. Additionally, color, odor, and turbidity are also removed so as to make the treated water safe for human consumption. The contaminants, particulate matter, etc., removed during the purification process are contained within the water purification system and can be readily disposed after a prescribed time interval. The water purification device also improves the pH of the water from very basic pH to about neutral pH.
[0044] Although embodiments for a water purification device have been
described in language specific to structural features and methods, it is to be understood that the invention is not necessarily limited to the specific features or methods described.

Rather, the specific features and methods are disclosed as exemplary implementations for the water purification device.

I/We claim;
1. A device (100) for purification of contaminated water (106), the device (100) comprising:
at least one dosing unit (110) to provide at least one chemical to the contaminated water (106) resulting in formation of floc water having flocs, wherein the flocs comprise a portion of contaminant ions removed from the contaminated water (106); and at least one treatment unit (116) to provide purified water (118), the treatment unit (116) comprising,
at least one floc separator (502) to provide floc-free water (506) by removing the flocs from the floc water, wherein the floc water is received from the dosing unit (110) under an influence of gravity; and at least one adsorber (504) to selectively adsorb a substantial portion of remaining contaminant ions from the floe-free water to provide purified water (118).
2. The device (100) as claimed in claim 1 further comprises at least one stirring unit (114) disposed in a fluid communication path between the dosing unit (110) and the treatment unit (116) to mix the chemical with the contaminated water (106).
3. The device (100) as claimed in claim 2, wherein the dosing unit (110) and the stirring unit (114) are made of a material selected from at least one of polyethylene, polypropylene, acrylonitrile butadiene styrene, polycarbonate, polyethylene terepthalate, low density polyethylene, high density polyethylene, polystyrene, polyvinyl chloride, polytetrafluoroethylene, nylons, polyesters, acrylics, polyolefins, polyurethanes, polyamides, polycarboxyamides, phenolics, polylactic acids, and rubbers.
4. The device (100) as claimed in claim 1, wherein the dosing unit (110) comprises:
at least one chamber (202) to store the chemical in liquid form;
a measuring unit (206) to meter and dispense a predetermined amount of
chemical into the contaminated water (106); and a casing (204) to connect the chamber (202) with the measuring unit (206).
5. The device (100) as claimed in claim 1 removes at least one of arsenic ions,
fluorides, and microbial contaminants from the contaminated water (106).

6. The device (100) as claimed in claim 1, wherein the chemical is a solution of a metal salt selected from at least one of aluminium acetate, aluminium chloride, aluminium hydroxide, aluminium sulphate, aluminium nitrate, aluminium carbonate, ferric bromide, ferrous carbonate, ferrous chloride, ferrous hydroxide, ferrous sulphate, ferrous oxalate, ferric sulphate, and ferric chloride.
7. The device (100) as claimed in claim 1, wherein the dosing unit (110) provides another chemical, wherein the other chemical is a base solution of an alkali and an alkali earth metal.
8. The device (100) as claimed in claim I, wherein the adsorber (504) comprises a vessel filled with adsorption media.
9. The device (100) as claimed in claim 8, wherein the adsoption media (508) is at least one of aluminum hydroxide coated with rice husk ash, activated alumina, bone char, and ferric hydroxide coated with rice husk ash.
10. The device (100) as claimed in claim 1 further removes turbidity, odor and color from the contaminated water (106).
11. The device (100) as claimed in claim 1, wherein the floc separator (502) is made of a porous cloth material made from at least one of cotton, canvas, felt, nylon, polypropylene, polyamide polyester, and polyvinylalcohol.
12. A method for purification of contaminated water, the method comprising:
providing at least one chemical to the contaminated water (106);
mixing the chemical with the contaminated water (106), wherein the mixing leads to formation of floc water having flocs, and wherein the flocs comprise a portion of contaminant ions removed from the contaminated water (106); separating the flocs from the floc water under an influence of gravity to provide
floc-free water; and selectively adsorbing a substantial portion of remaining ions from the floc-free water to provide purified water (118).
13. The method of purification of water as claimed in claim 12, wherein the providing comprises metering the chemical to provide a metered dose of chemical into the contaminated water (106), wherein the metered dose is based on a volume of the contaminated water (106).
14. The method as claimed in claim 12, wherein the providing comprises:
filling a casing (204) with the chemical up to a threshold level; filing a measuring unit (206) with the chemical up to a predetermined height, wherein the chemical is received from the casing (204); and dispensing the chemical into the contaminated water (106) by sliding the measuring unit (206) in an outward direction, wherein an amount of the chemical dispensed is based on a volume of the contaminated water (106). 15. The method as claimed in claim 14, wherein the dispensing further comprises resetting the measuring unit (206) by pulling the measuring unit (206) in an inward direction such that an opening (210) opens within the casing (204).