DRINKING WATER FILTRATION

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• Rahman Alam
• Mahadevanna U

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Guided by-Prof. Yunus Patel

Prof. SN Singh

Indian Institute of Technology Delhi

Drinking Water filtration system

https://quenchwater.com/blog/hippocrates-father-of-water-filters/

Indian Institute of Technology Delhi

Status of Indian drinking Water

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1. India stands 120th among 122 nations for its water quality.
2. Old and leaking pipes, leeching materials and water storage tanks often causes contamination.
3. The tap water in India is generally not fit for drinking.

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References://www.kent.co.in/blog/3-facts-about-drinking-water-in-india-why-a-water-purifier-is-a-must/

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Do we need water filter in India?

According to the survey, merely 107.42 million households in India have access to tap water, and only 78.88 million households are getting treated tap water. Even if a significant amount of tap water is treated in India, there is no assurance of water being free from all types of contaminants.

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1. Turbidity free water.
2. Water with good taste.(PH level)

3) Water free from disease causing micro-organisms.

4)Reduce Water wastage in water filter systems.

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References://www.kent.co.in/blog/3-facts-about-drinking-water-in-india-why-a-water-purifier-is-a-must/

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What do people need?

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Introduction to impurities in water

Why we need water filtration-

For healthy life we need to drink a clean water. That clean is just not mean the visibly clean that Means it should be free of any contamination, harmful minerals, bacteria, pesticides and should be good in taste.

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What is inside the water which harms us?

Lets us discuss about some insight of water what it contains. According to IS10500 standard these are the following impurity can be present and we will see the allowable limit as well for those impurities to be in safer side.

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Type of impurity

Radioactive Substances

Toxic Substances

Concerning Substances

Pesticide Residues

Bacteriological Quality of Drinking Water

Physical Parameters

These six are broad classification .

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Concerning substance

Impurities Limit

Reference-Table 2 General Parameters Concerning Substances Undesirable in Excessive Amounts (Foreword and Clause 4)

Indian Standard DRINKING WATER — SPECIFICATION ( Second Revision )

Like wise we can get other impurities limit in the following Standard in following tables

• Table 3 Parameters Concerning Toxic Substances
• Table 4 Parameters Concerning Radioactive Substances
• Table 5 Pesticide Residues Limits and Test Method
• Table 6 Bacteriological Quality of Drinking Water
• Table 1 Organoleptic and Physical Parameters

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Basic water treatment process

• Screening
• Flocculation & Coagulation
• Sedimentation clarifiers
• Precipitation
• Adsorption
• Filters
• Disinfection
• Fluorination
• Storage

Impurity cleaned-Debris, wood, small animals

Very small particle which don’t settle by their own.

Commonly used coagulant-Aluminium sulphate ( Al2(SO4)3).

Particle which get settle down

Fluoride addition for teeth protection

Commonly use filtration process-gravity filter

UV disinfection

We will now study the Advanced filtration technology widely used now a days.

figure 1.1

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Technological Development for Water Purification

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These are the technologies which can be combined to make system for water purification

Boiling

Ceramic bead

Moringa seeds

Coagulation

Charcoal/Activated carbon

Sedimentation

Three container

Method

Distillation

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Technology Description

Boiling-(First in China and then many millennia later in the Near East and Europe)

• Need of boiling was just to cook food at the time it was used years ago.
• Boiling was used 26000 years ago by our early human for just to make foods, without even knowing about what it is doing to the water apart from heating it.
• More than 300 years ago, the Dutch microbiologist Antoni van Leeuwenhoek was the first person to see microbial cells under a microscope.
• Purification by this process just mean killing viruses, cysts and microbes by heating them

to death, and it is effective in killing number of pathogens as fungi, protozoa.

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Why need another process to clean water??

• Boiling can’t remove sediments and sand and metal particles. So, it is not suitable for such type of water sources.
• Taste was also getting changed.

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Ceramic Beads-(Egyptians)

• Made of very pure clay.
• It purify the water and improves its taste.
• Removes chlorine, limestone and other residues.
• Easy reusable.(lifetime).

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Why need another process to clean water??

• Direct contact leads to contamination if not taken care of cleanliness of beads.
• Don’t remove the viruses and other contaminates.

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Harappan civilisation

Technology Description

Moringa Seeds-

• Used for mud rich water.
• Used to remove viruses which was prone to spread some disease, by use of a special proteins which binds mud particle hence the viruses.
• They just absorb the mud carrying the viruses at the bottom, because they are positively charged and clear the cloudy water.

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Why need another process to clean water??

• Direct contact leads to contamination if not taken care of cleanliness of beads.
• Don’t remove the heavy contaminates like sand and metal parts.

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Coagulation-(After 1500 BC, the Egyptians first discovered )

• First used alum as coagulant to settle down the particles.
• The commonly used metal coagulants fall into two general categories: those based on aluminum and those based on iron.
• They discharge the impurity and make them disable and they got bigger in size to settle down as floc.
• Aluminum sulfate (alum) as aluminum-based coagulant.

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Why need another process to clean water??

• Costly process as coagulants are costly.
• Sometimes more than one coagulant needed depending upon the type

of impurity/particle presents.

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Technology Description

Charcoal/Activated carbon-(B. A. Zwoyer of Pennsylvania in 1897)

• Used mainly for heavy metals , viruses ,many pollutants(radon , fluorine, pharmaceutical and oils).
• This work on the adsorption principle.
• Improve the taste.

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Why need another process to clean water??

• Filter must be replaced regularly.
• Skilled labor required, at least occasionally.
• Water analysis is required to choose the most adapted type of activated carbon.
• Contaminants are separated from water but not destroyed.

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Sedimentation-(Edmund Faustyn Biernacki (1866-1911))

• Physical water treatment process using gravity to remove suspended solids from water.
• It basically use to reduce the particle concentration in water.
• Minimizes the use of coagulation process, also used to accelerate the filtration process.

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Why need another process to clean water??

• Chemical contamination.
• Dissolved oxygen.
• Infectious substances.
• Instream barriers and altered water flow.
• Modified habitat.
• Time taking

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Combination of Technology

Technology Description

Three container method-

• It is a smaller version of sedimentation for home use.
• 3 bucket used in rotation so that we get continues supply of water.

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Why need another process to clean water??

• Not good for contaminated water.
• Time taking

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Distillation

• Heating the water above its boiling point.​
• Steam formed is condensed and collected at another end. ​
• Non-volatile impurities are left behind.​

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Why need another process to clean water??

• Removes taste
• Decrease in metabolic function
• More urination problem
• laboratory and industrial scale
• Expensive
• Slow
• Not maintenance friendly

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Sand and Gravel water filter(14^th century)

Ancient Greeks and Indians were using this

Method. Water is made to pass through the layers of sand

And gravel. Impurities of considerable size are removed

from this process.

It was needed as its simple and able to remove

Some turbidity of water.

Why its not in much practice?

1. Not able to get fully turbidity free water.
2. No Taste enhancement.

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Reference: https://www.aquaoxwaterfilters.com/the-history-of-water-filters/

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Sand and gravel filter

Technology Description

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Chlorination(1744,Sweden)�

Need: Chlorine was used to remove odours from the water, later as disinfectant.

• Its effective against most of bacteria and viruses and residual avoids regrowth.
• Some protozoan cysts are resistant for chlorine
• The main objective of this chlorine addition is to disinfect the water and maintain chlorine residuals that will remain in the water as it travels through the distribution system.

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Technology Description

Why it is popular?

• 1)Cost effective 2)Dependable 3)No Immediate Threat

Why there is a need for alternate process?

1)Chlorine gas is an irritant and not effective against all microbes.

2)Chlorine by-products are harmful for humans.

3)Chronic use causes cancer.

Benefits of chlorinated water in controlling infectious diseases outweigh the risks associated with chlorination and would not be enough to justify its discontinuation.

Currently Chloramine is substituting Chlorine in some countries.

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Scope and shortcomings of Chlorination

Technology Description

Adsorption-

• Vander Waals and Hydrogen bonds are the reason for this process.
• Mass treatment process.
• Depending on the impurity need to choose the adsorbate.
• A surface phenomenon.
• powdered activated carbon (PAC) and (granular)GAC are primary

adsorbate.

• Silica gel, Alumina also used as adsorbate.
• Generally physical adsorption is used to treat water.
• The graphite structure gives the carbon it's very large

surface area which allows the carbon to adsorb a wide range of impurity

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Why need another process to clean water??

• Relatively high capital cost
• Spent adsorbent may be considered a hazardous waste
• Adsorbent progressively deteriorating in capacity as number of cycles increases
• Need a more robust and lasting solution for mass treatment

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Activation means adsorption capability addition

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Technology Description

• It is a very general setup For adsorption technology for water treatment.
• Depending on the impurity present we use the adsorbate in spoons

A general setup for adsorption process

Activated carbon has the strongest physical adsorption forces or the highest volume of adsorbing porosity of any material known to mankind.

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Technology Description

Sand filteration-

• Sand filtration indirectly relates to very huge mass treatment of water.
• This is not a primary process of treating water unlike sedimentation.
• Rapid and slow sand filtration based on the size of sand.
• Long life
• Solid particles, sludge, insects, seeds, precipitated iron and manganese particles, and protozoa and bacteria can also be reduced

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Why need another process to clean water??

• Not as effective on virus(0.1 micron)
• No chlorine residual protection
• Difficult to transport due to weight
• Due to direct contact recontamination problem

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Technology Description

Claims- Basically on the type of sand(Zeolite)

And the thickness provided to various beds.

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Ceramic Water filtration

• In 1827, inventor and potter Henry Doulton discovered that filtering water through porous ceramic media would remove waterborne pathogens like cholera from drinking water.

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Benefits

• Simplicity of use and acceptability
• Proven reduction of diarrheal disease incidence for users
• A low one-time cost and portable

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References:https://www.cdc.gov/safewater/ceramic-filtration.html

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Technology Description

Evolution of Ceramic filtration

Fig 2: First patented ceramics

Fig1: Patented setup for water filtration

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Technology Description

• In the year 1980, Dr.Fernando fully redesigned the system.

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• He added plastic receptacle surrounding the ceramic filter and plastic faucet is provided and made it very user friendly.

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• He impregnated filter with colloidal silver, which takes care of the pathogens.
• He donated his design to humanity and never claimed this intellectual property.

References:https://www.pottersforpeace.org/

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Technology Description

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Scope of Ceramic filtration

• It has been instrumental in satisfying drinking water needs in disaster struck areas all over the world
• In backward African countries, its still being used to provide clean water at the  lowest cost possible.

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Why do we need to overlook this method?

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• Not as effective against viruses
• Variable quality control for locally produced filters
• Filters can break over time – need for spare parts
• A low flow rate of 1-3 liters per hour for non-turbid waters
• Filters and receptacles must be cleaned regularly, especially after filtering turbid water

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Technology Description

Technology Description

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UV light Dis-infection-(Natural Way)

• Discovered 90 year back before it used as disinfectant for water.(1801 by Johan Ritter)
• This method is also an extension of SODIS(1990)(Solar water infection) method.
• Before water they used first for killings germs from air.
• Wavelength 253.7 nanometres(for water treatment)
• Bacteria, Viruses, algae, microorganism,(leave them dead cant grow further)
• Economical among all available disinfectant methods
• Fastest
• Mercury vapour lamp used to generate UV light in system.

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Why need another process to clean water??

• Don’t remove dissolved impurities(Fluoride,

arsenic, pesticides)

• Can't be used on muddy water
• Can’t be used as primary process
• Need to change the UV light source frequently

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https://www.alfaauv.com/blog/uv-disinfection-system-water-treatment/

https://mro.massey.ac.nz/bitstream/handle/10179/6847/02_whole.pdf?sequence=3&isAllowed=y

Technology Description

Indian Institute of Technology Delhi

2007(ACTIVE)

https://mro.massey.ac.nz/bitstream/handle/10179/6847/02_whole.pdf?sequence=3&isAllowed=y

Patent 1

Patent 2

Patent Not Granted

1996

Technology Description

Indian Institute of Technology Delhi

Bag Filters-(Purpose-Brewing/Ground water treatment)

• Discovered or used only for pre-treated water or used at pre-treatment.
• Industrial use as brewing, agriculture water, cleaning water treatment
• Very high flowrate(90-2400 gallons/min)
• Easy install/Uninstall
• Cost effective for mass treatment
• Less often change of filter(low maintain ace cost)

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Why need another process to clean water??

• Not effective or don’t remove fine particles,

viruses, bacteria and chemicals

• It is only used where mass treatment and cost

criteria is present

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1-200micron

Technology Description

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Ozone Treatment

• Ozone is a powerful oxidising agent which, when dissolved in water, produces a broad spectrum biocide that destroys all bacteria, viruses and cysts.
• It is better Oxidizing agent than Chlorine.
• In Many Muncipal bodies, Ozone being used in place of chlorine and saved Bottle industry in 1980s.

Developments of Ozone Method

• 1857 - Werner Von Siemens designed an ozone generator, now known as the “Siemens Type” ozone generator.
• Marius Paul Otto began studying ozone at La Sorbonne University, in Paris.
• 1893 - Ousbaden, in Holland, get the world’s first water treatment plant using ozone. Ozone is also used for the first time in Algae control.

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Von siemen ozone setup

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Technical Description

Tesla patented ozone generator

•  Nikola Tesla patents his first ozone generator.​

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•   (1903)Niagara Falls, in USA, get the first U.S. drinking water installation ozone treated.​

Scope of Ozone water Treatment

1)  Ozone saved the bottled water industry in the early days when bottled water wasn’t always properly disinfected and was frequently criticized.

2) Still Ozone water treatment is being in many industries to disinfect Bottled water.

3)It leaves no residue unlike Chlorination.

4)Very fast  process.

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Why there was need to overlook this process and look for other Methods?

1) It is expensive for small scale, so Chlorine is still preferred over Ozone.

2)Short Half life, difficult to store and transport it.

3)Ozone exposure Causes headache , irritation of eyes.

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Technology Description

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Micro Filteration/Ultra filteration/Nanofilteration/ROfilteration

• These technology developed for getting water with very good quality.
• In simple they use same technology but the filtering out impurity are different.
• Nanofiltration was just a cost reduction compared to RO and better performant compared to UF.
• Challenge is to develop micro to nano pores of sieve.
• Cleaning and maintenance is very high.
• Pressure range 2-17 bar(30-250 psi) but for sea water it is 27 bar

Truck tire pressure(7bar)

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Why need another process to clean water??

• They waste a lot of water due to cleaning process of itself.
• Can't be leave dry.
• Very slow process
• Costly.
• Skilled labor required for maintenance and production
• Filter out everything which is even necessary
• Need extra filter to add minerals for drinking
• Long term effect of RO treated water are tiredness ,heart disease, Muscle cramps

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https://www.youtube.com/watch?v=h7SpkI52ZP4

Technology Description

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Fig1-SEM image at 600X

Fig2-SEM image at 2700X during the manufacturing(faced roller side)

Fig3-SEM image at 500X during the manufacturing(Faced roller side)

Fig4-SEM image at 2000X during the manufacturing(Faced air side)

Membrane material- polysulfone or polyethersulfone

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Other similar patents

• U.S. Pat. No. 5,866,059
• U.S. Pat. No. 5,906,742
• U.S. Pat. No. 4,933,081
• EP-A-361 085

All hydrophobic so need other process to make hydrophilic

https://www.youtube.com/watch?v=LCt0Brm0bO8

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Centrifugal water treatment

• Industrial purpose
• For very high flow rate
• Low maintenance cost
• Uses the principal that heavy particles will be on periphery
• Removal of sludge
• Can be use to remove oil

Why need another process to clean water??

• Do not remove virus, contaminants
• Costly
• Very high-power consumption

Technology Description

Iodination

• Iodine  is an oxidizing agent and plays same role as chlorine.
• Iodine is one of the oldest forms of water purification. Iodine comes either as a water purification tablet or a disinfectant solution.
• It does a good job in freeing water from bacteria, cysts and viruses.
• Residuals reaches the other place and disinfects them.

Adding Tincture to purify water

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Technology Description

Scope of Iodination

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Technology Description

Bromination

• Available in pellets form and solutions.
• Directly added to water and plays same role as chlorine and  iodine.
• Has comparable pathogens killing capacity like chlorine and iodine.
• Bromine is widely found in spas and hot tubs, as it remains stable in hot water.
• it has less of a chemical odor than chlorine.

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Technology Description

Scope of Bromination

• Bromine is widely found in spas and hot tubs, as it remains stable in hot water
• Of the three halogens, bromine is favored in consumer opinion as determined in blind taste testing.
• It doesn’t leave  odor, taste  like chlorine and iodine and doesn’t affect thryoid patients like iodine.
• Mainly used in non-residential settings, for example, aboard ships and on oil and gas drilling/production platforms.
• Why it failed in most of the places?
• The decision on whether bromine can serve as a disinfectant for drinking-water and wastewater treatment is likely to be a balance between the dose required to achieve efficacy  its advantages over other disinfectants, particularly chlorine.
• nasty reddish-brown liquid that is hazardous to handle and harmful byproducts.

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Technology Description

Thankyou

Have a nice day

https://www.wsj.com/articles/BL-IRTB-31726

Annexure

Filtration Technologies

Few emerging technologies for filtration process.

• Depth Filtration
• Surface Filtration

Why we need so many different types of filters??

• Type of impurity
• Place where water need to be used
• Type of input water source
• Size of the impurity
• Size of the filtration Unit
• Cost of the Unit

Deep Filtration:

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This technology is used to clean dirt, organic solids, grit, rust particles, wooden pieces etc. These filter comes in cartridge form. These cartridge are made of cotton and glass fibre ,polypropylene. These cartridge just work as a siew which just stops the particle from passing from the layer of cartridge. As the depth of cartridge increases, smaller size of particles get stuck in cartridge and get filter out as shown in figure 1.3 . This sieving mechanism is called mechanical retention. This way outer layer capture the bigger size impurities and inner layer captures the smaller size of impurities.

figure 1.2

Filtration Technologies

Surface Filtration:

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This process of filtering the particulate impurities works on the surface phenomenon. Particle will only be retained by the surface of the media. There will be form cakes which will increase the efficiency of process. This is less expensive than the depth filtration process. By playing with the surface area we can increase or decrease the efficiency and flowrates of water to be filtered.

figure 1.3

figure 1.4 schematic of surface and deep filtration

Complete water solution

3M

Ecolab

Parker hannifen

Donaldson company

Reference:https://www.safewater.org/fact-sheets-1/2017/1/23/what-is-chlorination