Purification of drinkiing water by polymer based.By using membrane spearation,reverse osmosis

1. Title
Purification of drinking water by Polymer-based membrane
.

2. INTRODUCTION
Water borne diseases are common health issues all
over the world especially if the water quality is poor
To avoid the health issues arising from drinking water
people should consume clean water
The purification of water is a challenging issue,
especially in a less developed countries
The selection of proper method of water purification
depends on types of properties of impurities present in
water and the economic feasibility
Membrane filtration is a broadly used technique in
water purification

3. Membrane Separation process
 A membrane is a selective barrier that permits the
separation of certain species in a fluid by combination
of sieving and diffusion mechanisms.
 Membrane acts as a barrier and removes the
contaminating microorganisms from the desired liquid
or gas rather than destroying them.
Benefits:
 Can remove 90–100% pathogens from the water sample.
 This method is more energy efficient and can be easily scaled
up.
 It allows the filtration of any volumes of non-turbid water
through the disk.

4. Types of filtration
Principle: Pressure
driven operations
1.Microfiltration
2.Ultrafiltration
3.Nanofiltration
4.Reverse osmosis (RO)

6. MICROFILTRATION
It separates those particles that have a size range of 0.1 to
10 μm.
Low pressure treatment
It is a pre-treatment process of ultrafiltration and a post-
treatment process for granular media filtration.
APPLICATIONS:
Used to separate pathogens such as the protozoa
Cryptosporidium and Giardia lamblia, etc.
In industries, it is used for the cold sterilization of beverages
and pharmaceuticals.
It separates the macromolecules from proteins, large
molecules, or cell debris.
Cannot separate small viruses, sugars and salts.

7. ULTRAFILTRATION
 It is designed to eliminate proteins,
endotoxins, viruses, and silica.
 Generally, it retains those Suspended
solids and solutes which possess a high
molecular weight and pass those solutes
that have a low molecular weight such
as water.
 Pore size 0.1 μm to 0.01 μm.
 Ultrafiltration uses a pressure induced
separation of solutes from a solvent
through a semi permeable membrane.
APPLICATIONS :
 UF is used for the production of
potable water. It removes
the particulates and macromolecules
from raw water.
 Does not filter ionic particles like lead,
iron, chloride ions other charged
particles .

8. NANO FILTRATION:
 Typical pore size: 0.001
micron (10-9m)
Moderate pressure
Removes toxic or unwanted
bivalent ions (ions with 2 or
more charges), such as Lead,
Iron, Nickel, Mercury (II)

9. REVERSE OSMOSIS (RO):
 Typical pore size: 0.0001 micron i.e.(10^-10m)
 Very high pressure
 Only economically feasible large scale method
to remove salt from water
How RO Works ?
 Osmosis is a natural process that moves water
across a semipermeable membrane, from an
area of greater concentration to an area of
lesser concentration until the concentrations
are equal
 high pressure to push the water in the
opposite direction that it flows naturally

10. If RO Can Get Everything Out That Would Make Water Undrinkable,
Why Not Just Use RO Membranes by Themselves?
RO is Not for Everything! High pressure is required
to push the water through
the smallest pores
RO is the most expensive
filtration system
Because pores are so
small, big particles can
clog them (called fouling)
This makes the filtering
membrane unusable.

11. BEST SOLUTION:

12. What is fouling in filtration?
• Fouling occurs when contaminants
collect on the surface or in the pores of
a filtration membrane.
• REMEDIES:
• Mechanical Cleaning - It involves the
breakdown of contaminants from the
membrane through the use of physical force.
Common methods include vibrations and
backwards or forward flushing.
• Chemical Cleaning - It involves the usage of
acids, chemical solutions, and dispersants
which help in breaking down the foulants from
the surface of the membrane.

13. Process Design Considerations
 Pre-treatment:
Treatment of feed prior to the membrane is essential to prevent damages to the membrane and minimise
the effect of fouling which greatly reduce the efficiency of the separation
 Membrane specifications :
1. Material
2. pore size
 Operation strategy:
 Flow type
 Flow velocity
 Flow temperature
 Pressure

14. Advantages of using
membrane separation:
 No complex instrumentation
Membranes are relatively
expensive
 Separation can be done continuously. Low membrane lifetime
 Membrane properties are variable
and can be adjusted
Synthetics are not effectively
treated by this method
 Greater design flexibility in designing
systems
Oil emulsions are not “chemically
separated “,so secondary oil recovery
can be difficult
 Clean technology with operational
ease
Disadvantages of usingMembrane
Separation:
Certain solvents, especially graphite and other residues can
quickly and permanently destroy the membrane surfaces