Process and apparatus for purification of water

Patent metadata

Field	Value
Publication number	US-10654728-B2
Application number	US-201515125937-A
Country	US
Kind code	B2
Filing date	Mar 7, 2015
Priority date	Mar 14, 2014
Publication date	May 19, 2020
Grant date	May 19, 2020

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

What is claimed is:

1. A process for removing arsenic and inactivating microorganisms from arsenic and microorganisms laden water in a point of use water purification system;
said process comprising:
preparing granulated arsenic removal media ( 144 ) by:
adding ferric chloride in an amount ranging from 5 to 30% weight/volume and sodium hydroxide in an amount ranging from 5 to 40% weight/volume 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 decantation and 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, the granulated matter represents the granulated arsenic removal media ( 144 ); and

preparing a bed of granulated arsenic removal media ( 140 ) by holding the granulated arsenic removal media ( 144 ) between a mesh and a cloth, and
removing arsenic from the arsenic and microorganisms laden water by leading a flow of the arsenic and microorganisms laden water, against gravity, through the bed of granulated arsenic removal media ( 140 ) to produce a flow of microorganisms laden water with reduced arsenic content, wherein the bed of granulated arsenic removal media ( 140 ) comprises iron compounds in an amount ranging from 30 to 70% of the total mass of the bed, the granulated arsenic removal media ( 144 ) having particle size ranging from 400 to 1000 micrometers and surface area ranging from 50 to 400 m 2 /g, and
regulating a contact time between said arsenic and microorganisms laden water and said bed of granulated arsenic removal media ( 140 ) by regulating the flow of microorganisms laden water with reduced arsenic content, with a nozzle (N), the contact time ranging from 5 to 30 minutes; and
inactivating microorganisms in the water laden with microorganisms with reduced arsenic content by leading the water laden with microorganisms with reduced arsenic content through a disinfectant releasing system which releases at least one disinfectant in the water laden with microorganisms 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, wherein the point of use water purification system does not need electricity and continuous supply of water for performing the process of removing arsenic and inactivating microorganisms from the arsenic and microorganisms laden water.

2. The process according to claim 1 wherein the process for preparation of said granulated arsenic removal media ( 144 ) comprises 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 according to claim 1 , wherein said iron compounds include iron oxide, iron hydroxide and iron-oxy hydroxide.

5. The process according to claim 1 , wherein said disinfectant releasing system comprises at least one spring ( 168 ) mounted with loaded disinfectant releasing tablet ( 170 ) in a chamber, wherein said disinfectant releasing tablet ( 170 ) is biased 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).

6. The process according to claim 5 , 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.

7. 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 ).

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

9. 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 against gravity, and adsorb the arsenic present in said water to obtain a flow of microorganism laden water with reduced arsenic content, wherein the granulated arsenic removal media ( 144 ) is prepared by:
adding ferric chloride in an amount ranging from 5 to 30% weight/volume and sodium hydroxide in an amount ranging from 5 to 40% weight/volume 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 decantation and 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, the granulated matter represents the granulated arsenic removal media ( 144 ); and wherein the bed of granulated arsenic removal media ( 140 ) comprises iron compounds in an amount ranging from 30 to 70% of the total mass of the bed, the granulated arsenic removal media ( 144 ) having particle size ranging from 400 to 1000 micrometers and surface area ranging from 50 to 400 m 2 / g;

a first outlet ( 162 ) adapted to receive the flow of microorganism laden water with reduced arsenic content; and
a cloth ( 148 ), having pore size ranging from 3 micrometer to 20 micrometer, fitted operatively over said bed of granulated arsenic removal media ( 140 ) and between said bed of granulated arsenic removal media ( 140 ) and said first outlet ( 162 ) adapted to trap fine particles in the water with reduced arsenic content and permit passage of the microorganism laden 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 microorganism laden water with reduced arsenic content

Assignees

• Tata Consultancy Services Ltd

Inventors

• Kausley Shankar Balajirao
• Malhotra Chetan Premkumar
• Ahmad Dilshad

Classifications

• B01J20/3085

  Chemical treatments not covered by groups B01J20/3007 - B01J20/3078 · CPC title

• C02F2209/40

  Liquid flow rate · CPC title

• C02F1/001

  Processes for the treatment of water whereby the filtration technique is of importance (C02F1/44 takes precedence; construction of filters in general B01D24/00 - B01D41/00) · CPC title

• C02F1/76

  with halogens or compounds of halogens {(C02F1/4674 takes precedence)} · CPC title

• C02F2307/10

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