4. contents
O What is Ultrafiltration?
O Ultrafiltration
O How It Works ?
O Benefits
O What does ultrafiltration remove?
O Maintenance
O Reverse osmosis
O History of RO
O Uses
Drinking water purification
Military use: the reverse osmosis water purification unit
Water and wastewater purification
Food industry
O Acknowledgement
O References
4
5. What is Ultrafiltration?
O UF physically separates solids from liquid
streams based on the principle of size-
exclusion.
O Ultrafiltration (UF) is a membrane filtration
process similar to Reverse Osmosis, using
hydrostatic pressure to force water through a
semi-permeable membrane. The pore size of
the ultrafiltration membrane is usually 103 -
106 Daltons. Ultrafiltration (UF) is a pressure-
driven barrier to suspended solids, bacteria,
viruses, endotoxins and other pathogens to
produce water with very high purity and low
silt density. 5
6. Ultrafiltration
O Ultrafiltration (UF) is a variety of membrane
filtration in which hydrostatic pressure forces a
liquid against a semi permeable membrane.
Suspended solids and solutes of high
molecular weight are retained, while water
and low molecular weight solutes pass
through the membrane. Ultrafiltration is not
fundamentally different from reverse osmosis,
microfiltration or nanofiltration, except in terms
of the size of the molecules it retains.
6
7. Cont:
A membrane or, more properly, a semi
permeable membrane, is a thin layer of material
capable of separating substances when a
driving force is applied across the membrane.
Once considered a viable technology only for
desalination, membrane processes are
increasingly employed for removal of bacteria
and other microorganisms, particulate material,
and natural organic material, which can impart
color, tastes, and odors to the water and react
with disinfectants to form disinfection byproducts
(DBP).
7
8. Cont:
O Ultrafiltration (UF) is used to remove
essentially all colloidal particles (0.01 to 1.0
microns) from water and some of the largest
dissolved contaminants. The pore size in a UF
membrane is mainly responsible for
determining the type and size of contaminants
removed. In general, membrane pores range
in size from 0.005 to 0.1 micron. UF
membrane manufacturers classify each UF
product as having a specific molecular weight
cutoff (MWC), which is a rough measurement
of the size of contaminants removed by a
given UF membrane
8
10. Cont:
O This separation process is used in
indZstry and research for purifying and
concentration macromolecular (103-
106DA) solutions, specially protein
solutions. Pore diameters in the 10-1000
range.
O Uf is a veriety of membrane filtration in
wich forces like pressure and
concentration gradients lead to separate
through a semipermeable membrane.
10
11. Uses
O In industries such as chemical and pharmaceutical
manufacturing food and beverages, and waste water
treatment, employ UF in order to recycle flow or add
value to later products. Blood dialysis also utilizes
UF. Drinking water can be used for the removal of
particulates and macromolecules from row water to
produce potable water. This process is currently used
as traditional treatment methods for following
reasons:-
O No chemicals requires
O Constant product quality regardless of feed quality
O Compact plant size
O Capable of exceeding regulatory standards of water
quality, achieving 90-100% pathogen removal.
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12. Other uses are
O filtration of effluent from paper pulp mill
O Cheese manufacture
O Removal of bacteria from milk
O Process and waste water treatment
O Enzyme recovery
O fruit juice concentration and clarification
O radiocarbon dating of bone collagen
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13. How It Works
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Ultrafiltration uses hollow fibers of membrane material and the feed water
flows either inside the shell, or in the lumen of the fibers. Suspended
solids and solutes of high molecular weight are retained, while water and
low molecular weight solutes pass through the membrane. Ultrafiltration is
not fundamentally different from reverse osmosis, microfiltration or
nanofiltration, except in terms of the size of the molecules it retains. When
strategically combined with other purification technologies in a complete
water system, UF is ideal for the removal of colloids, proteins, bacteria,
pyrogens, proteins, and macromolecules larger than the membrane pore
size from water.
15. Benefits
O No need for chemicals (coagulants,
flocculates, disinfectants, pH adjustment)
O Size-exclusion filtration as opposed to media
depth filtration
O Good and constant quality of the treated water
in terms of particle and microbial removal
O Process and plant compactness
O Simple automation
O Environment friendly
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16. What does ultrafiltration remove?
O Endotoxins
O Plastics
O Proteins
O Silica
O Silt
O Smog
O Viruses
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17. Maintenance
O Ultrafiltration systems contain extremely fine
membrane filters which need to be properly
cleaned. The cleaning process used depends on
whether a UF system is being used to remove
organic or inorganic contaminants, or even both.
To remove organic contaminants the general
cleaning protocol for the cleaning of tubular
membranes is to use a low foam, medium alkaline
detergent at 0.6% to 1% for a maximum of 40 to 60
minutes. To remove inorganic contaminants the
best treatment is with citric acid at a maximum
concentration of 3.0 %. The acid should circulate
for 1 to 3 hours. Hydrochloric acid can also be
used to clean membranes, as can oxalic, sulfuric
and nitric acid.
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18. types of filtration
O Membrane modules come in two basic
configurations;
1- self-contained, and 2- open immersion type.
The most common module type for UF and RO
membranes is the self-contained (or housed)
membrane module where feed water is pumped
through the housing. All feed, concentrate, and
filtrate piping connections are integral to the
module. Typical module variations are shown
below.
The open immersion type modules are placed
into the feed water tank with the membrane
exposed.
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19. Reverse osmosis
O Reverse osmosis (RO) is a water purification technology
that uses a semipermeable membrane to
remove ions, moleculesand larger particles from drinking
water. In reverse osmosis, an applied pressure is used to
overcome osmotic pressure, a colligative property, that is
driven by chemical potential differences of the solvent,
a thermodynamic parameter. Reverse osmosis can remove
many types of dissolved and suspended species from
water, including bacteria, and is used in both industrial
processes and the production of potable water. The result is
that the solute is retained on the pressurized side of the
membrane and the pure solvent is allowed to pass to the
other side. To be "selective", this membrane should not
allow large molecules or ions through the pores (holes), but
should allow smaller components of the solution (such as
solvent molecules) to pass freely.
19
20. Cont:
O In the normal osmosis process, the solvent
naturally moves from an area of low solute
concentration (high water potential), through a
membrane, to an area of high solute concentration
(low water potential). The driving force for the
movement of the solvent is the reduction in the
free energy of the system when the difference in
solvent concentration on either side of a
membrane is reduced, generating osmotic
pressure due to the solvent moving into the more
concentrated solution. Applying an external
pressure to reverse the natural flow of pure
solvent, thus, is reverse osmosis. The process is
similar to other membrane technology
applications.
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23. History of ro
O A process of osmosis through semipermeable
membranes was first observed in 1748 by Jean-
Antoine Nollet. For the following 200 years,
osmosis was only a phenomenon observed in the
laboratory. In 1950, the University of California at
Los Angeles first investigated desalination of
seawater using semipermeable membranes. In
1977 Cape Coral, Florida became the first
municipality in the United States to use the RO
process on a large scale with an initial operating
capacity of 11.35 million liters (3 million US gal)
per day. By 1985, due to the rapid growth in
population of Cape Coral, the city had the largest
low pressure reverse osmosis plant in the world,
capable of producing 56.8 million liters (15 million
US gal) per day (MGD).
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24. Uses
O Drinking water purification
O Around the world, household drinking water purification systems, including a
reverse osmosis step, are commonly used for improving water for drinking
and cooking.
O Such systems typically include a number of steps:
O a sediment filter to trap particles, including rust and calcium carbonate
O optionally, a second sediment filter with smaller pores
O an activated carbon filter to trap organic chemicals and chlorine, which will
attack and degrade thin film composite membrane reverse osmosis
membranes
O a reverse osmosis filter, which is a thin film composite membrane
O optionally, a second carbon filter to capture those chemicals not removed by
the reverse osmosis membrane
O optionally an ultraviolet lamp for sterilizing any microbes that may escape
filtering by the reverse osmosis membrane
O The latest developments in the sphere include nano materials and
membranes.
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25. Military use: The reverse
osmosis water purification
unit
O A reverse osmosis water purification unit
(ROWPU) is a portable, self-contained water
treatment plant. Designed for military use, it can
provide potable water from nearly any water
source. There are many models in use by
the United States armed forces and
the Canadian Forces. Some models
are containerized, some are trailers, and some
are vehicles unto themselves.
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26. Water and wastewater
purification
O Rain water collected from storm drains is
purified with reverse osmosis water
processors and used for landscape irrigation
and industrial cooling in Los Angeles and other
cities, as a solution to the problem of water
shortages.
O In industry, reverse osmosis removes minerals
from boiler water at power plants. The water
is distilled multiple times. It must be as pure as
possible so it does not leave deposits on the
machinery or cause corrosion. The deposits
inside or outside the boiler tubes may result in
underperformance of the boiler, bringing down
its efficiency and resulting in poor steam
production, hence poor power production at
the turbine 26
27. Food industry
O In addition to desalination, reverse
osmosis is a more economical operation
for concentrating food liquids (such as
fruit juices) than conventional heat-
treatment processes. Research has been
done on concentration of orange juice and
tomato juice. Its advantages include a
lower operating cost and the ability to
avoid heat-treatment processes, which
makes it suitable for heat-sensitive
substances such as
the protein and enzymes found in most
food products. 27