A process and apparatus for purification of water

Patent metadata

Field	Value
Publication number	US-2018170772-A1
Application number	US-201515125937-A
Country	US
Kind code	A1
Filing date	Mar 7, 2015
Priority date	Mar 14, 2014
Publication date	Jun 21, 2018
Grant date	—

Abstract

The present disclosure relates to a process for the purification of water. The process includes leading water laden with microorganisms and arsenic through an arsenic adsorption media followed by treating the resultant arsenic deficient water with a disinfectant releasing system to obtain water deficient of arsenic and viable microorganisms. The present disclosure also provides an apparatus for the purification of water using the afore-stated process.

First claim

1 . A process for removing arsenic and inactivating microorganisms from arsenic and microorganisms laden water; said process comprising:
removing arsenic from said water by leading said water, against gravity, through a bed of granulated arsenic removal media ( 140 ) comprising iron compounds in an amount ranging from 30 to 70% of the total mass of the bed, said granulated media ( 144 ) having particle size ranging from 400 to 1000 micrometers and surface area ranging from 50 to 400 m 2 /g, for a time period ranging from 5 to 30 minutes, to obtain water with reduced arsenic content; and inactivating microorganisms in the water with reduced arsenic content by leading the water with reduced arsenic content through a disinfectant releasing system which releases at least one disinfectant in the water with reduced arsenic content at a rate ranging from 0.1 to 1 mg/liter to cause depletion of viable microbial content therein, to provide water deficient of arsenic and microorganisms, wherein said disinfectant is chlorine.

2 . The process according to claim 1 wherein said granulated arsenic removal media ( 144 ) is prepared by a process co p sing:
adding ferric chloride in an amount ranging from 5 to 30% w/v and sodium hydroxide in an amount ranging from 5 to 40% w/v, in water, at a pH ranging from 6.5 to 7 to obtain a slurry;
allowing said slurry to settle for a time period ranging from 1 to 8 hours to obtain a residue and a supernatant;
separating said supernatant from said residue by at least one method selected from the group consisting of decantation and vacuum filtration to obtain a cake;
drying said cake at a temperature ranging from 60 to 110° C. for a time period ranging from 8 to 24 hours to obtain a dried cake;
converting said dried cake to granulated matter; and
sieving said granulated matter to obtain the sized granulated arsenic removal media ( 144 ) having particle size ranging from 400 to 1000 micrometers and surface area ranging from 50 to 400 m2/g.

3 . The process according to claim 2 , wherein ferric chloride and sodium hydroxide are added in water simultaneously.

4 . The process, wherein the bed of granulated arsenic removal media ( 140 ) is prepared by holding the granulated arsenic removal media ( 144 ), prepared in accordance with claim 2 , in between a coarse mesh ( 146 ) and a cloth ( 148 ).

5 . The process according to claim 1 , wherein said iron compound is at least one selected from the group consisting of iron oxides, iron hydroxides, ironoxy-hydroxides.

6 . The process according to claim 1 , wherein said disinfectant releasing system is prepared by mounting at least one spring ( 168 ) loaded disinfectant releasing tablet ( 170 ) in a chamber, biasing said disinfectant releasing tablet ( 170 ) in a first compartment (IC) against a diffusion barrier ( 172 ) to release at least one fluidized disinfectant into the water with reduced arsenic content passing through a second compartment (IIC).

7 . The process according to claim 6 , wherein said disinfectant releasing tablet ( 172 ) comprises at least one disinfectant releasing compound selected from the group consisting of calcium hypochlorite, sodium dichloroisocyanurate, trichloroisocyanuric acid and N-chloro-p-toluenesulfonamide sodium salt (Chloramine T), in an amount ranging from 50 to 100% of the total mass of the tablet and at least one additive selected from the group consisting of vehicle, buffer, diluent, binder, glidant, lubricant, disintegrant, wetting agent, stabilizer, flavoring agent, sweetening agent, coating agent, preservative, dispersing agent, oil, wax, emulsifier, surfactant, gelling agent, opacifier, humectant, antioxidant, suspending agent, thickening agent, antifoaming agent and adsorbent, in an amount ranging from 0 to 50% of the total mass of the tablet.

8 . The process according to claim 1 , further comprising the step of leading the arsenic and microorganisms laden water through a filtration unit ( 198 ) before leading said water through the bed of granulated arsenic removal media ( 140 ).

9 . The process according to claim 1 , wherein the flow of the water with reduced arsenic content obtained in step 1(i) and allowed to flow into step 1(ii) and the contact time between said arsenic and microorganisms laden water and said bed of granulated arsenic removal media ( 140 ) is regulated by means of a nozzle (N).

10 . The process according to claim 1 , includes the step of monitoring the volume of water deficient of arsenic and microorganisms.

11 . An apparatus ( 300 ) for removing arsenic and inactivating microorganisms from arsenic and microorganisms laden water; said apparatus ( 300 ) comprising:
a first chamber (A) comprising:
a first inlet ( 142 ) adapted to receive said arsenic and microorganisms laden water;
a coarse mesh ( 146 ), having mesh size ranging from 20 mesh (841 micrometer) to 60 mesh (250 micrometer), adapted to permit the passage of said water received from said first inlet ( 142 ) there through;
a bed of granulated arsenic removal media ( 140 ) supported by said coarse mesh ( 146 ) adapted to allow the passage of said arsenic and microorganisms laden water and adsorb the arsenic present in said water to obtain water with reduced arsenic content;
a first outlet ( 162 ) adapted to receive the water with reduced arsenic content; and
a cloth ( 148 ), having pore size ranging from 3 micrometer to 20 micrometer, fitted operatively over said bed ( 140 ) and between said bed ( 140 ) and said first outlet ( 162 ) adapted to trap fine particles in the water with reduced arsenic content and permit passage of the water with reduced arsenic content there through to said first outlet ( 162 );
a second chamber (B) comprising a first compartment (IC) and a second compartment (IIC) operatively separated from said first compartment by a diffusion barrier ( 172 ), said first compartment being located operatively over the second compartment; said second chamber (B) comprising:
a second inlet ( 164 ) provided to said second compartment adapted to receive the water with reduced arsenic content from said first outlet ( 162 );
at least one disinfectant releasing tablet ( 170 ) provided in said first compartment adapted to release at least one disinfectant when moistened;
a diffusion barrier ( 172 ) adapted to regulate the diffusion of the released disinfectant;
at least one spring ( 168 ) provided in the first compartment adapted to bias said tablet(s) ( 170 ) against said diffusion barrier ( 172 ); and
a second outlet ( 180 ) provided to said second compartment adapted to receive the water deficient of arsenic and containing diffused disinfectant; and
a conduit ( 162 c ) configured to communicate liquid from said first outlet ( 162 ) to said second inlet ( 164 ), optionally comprising at least one nozzle (N) for regulating the contact time between said arsenic and microorganisms laden water and said bed of granulated arsenic removal media ( 140 ).

12 . The apparatus according to claim 11 , further includes at least one filtration unit ( 198 ).

13 . The apparatus according to claim 11 , further includes a life indicator to display the remaining life of the media ( 144 ).

14 . The apparatus according to claim 13 , wherein at least one dimension of the disinfectant releasing tablets ( 170 ) is used to indicate the remaining life of the apparatus.

Assignees

• Tata Consultancy Services Ltd

Inventors

• Kausley Shankar Balajirao
• Malhotra Chetan Premkumar
• Ahmad Dilshad

Classifications

• C02F2307/10

  as part of a potable water dispenser, e.g. for use in homes or offices · CPC title

• B01J20/28057

  Surface area, e.g. B.E.T specific surface area · CPC title

• C02F2101/103

  Arsenic compounds · CPC title

• C02F1/003

  using household-type filters for producing potable water, e.g. pitchers, bottles, faucet mounted devices (C02F9/20 takes precedence) · CPC title

• C02F2307/04

  as part of a pitcher or jug · CPC title