This document provides an overview of the water treatment process at JSW Energy Ltd. It discusses the various sources of water, types of impurities present, and steps taken in pre-treatment including coagulation, flocculation, sedimentation, and filtration. It then covers the demineralization process using ion exchange and describes the various unit operations involved, including strong acid cation, strong base anion, mixed bed, and ultrafiltration. The goal of the treatment is to remove impurities and produce high-quality demineralized water for use in power generation processes.

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Welcome to Training Programme
Water Treatment
Pre Treatment & Demineralization
1
JSW Energy
Ltd

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WATER
JSW Energy Ltd
 Molecular Formula – H2O
 Properties:
 Available in three different states.
 High heat storage capacity.
 High latent heat of evaporation.
 Universal solvent.
 Easy to handle.
Water is used in power plants for steam generation
& as cooling water

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JSW Energy Ltd
SOURCES
 Surface Water – Lakes, River, Dam.
 Ground Water – Wells, Deep Springs.
 Sea Water.

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IMPURITIES
 Insoluble
Silt, Mud, Colloidal matter, Organics, Microbes,
Algae.
 Soluble
 Organic - Natural organics
 Inorganic
 Cations – Ca, Mg, Na, K, Fe, Al, As,
 Anions – HCO3, CO3/ Cl, SO4, NO3, PO4, F, SiO2
 Gases - Oxygen, Carbon di oxide, Ammonia etc
If impurities are not removed from water they cause
Scale formation, fouling & corrosion in user systems

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JSW Energy Ltd
Water in Nature Contains
 Suspended impurities – Silt, Mud, Organic
debris, Colloidal matter, etc.
 Organic matter – Bacteria, Algae, Dissolved
Organic matter.
 Dissolved Matter – Mainly Salts of Alkali and
Alkaline earth metals.

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JSW Energy Ltd
Raw Water Treatment
Raw water treatment is divided in two main parts
External Treatment –
 Commonly known as Pre-Treatment.
 Used to remove un-dissolved as well as
dissolved impurities from water.
 Treatment choice varies with water
characteristics and application.
Internal Treatment –
 Commonly known as chemical treatment.
 Main objective to eliminate problems likes
scaling, corrosion, microbial growth.
 Treatment choice varies with make-up water
quality, equipment used & economy.

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JSW Energy Ltd
 Organic Matter – Chlorination.
 Suspended Matter – Coagulation /
Flocculation
 Dissolved Matter – R.O, Ion Exchange
 Steps 1 and 2 Comes Under Pre
Treatment.
 Pre Treatment is done to meet the process
and drinking water requirement and also to
maintain the plant cooling water system
and the DM Plant.
Recommended Treatments

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JSW Energy Ltd
The process of removing suspended matter.
- Coagulation
- Flocculation
- Sedimentation
Coagulation is the process of destabilisation by
charge neutralisation.
Finely divided particles suspended in surface water
repel each other because their surfaces are
predominantly negatively charged. Once
neutralised, particles no longer repel each other
and can be brought together. This is achieved by
adding inorganic salts of aluminium or iron which
neutralise the charge on the turbidity particle.
Eg. Alum.
CLARIFICATION

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JSW Energy Ltd
Flocculation is the process of bringing together the
destabilised or coagulated particles to form a
larger agglomeration or floc.
Coagulation and flocculation are aided and
enhanced by Coagulant / Flocculant aids like
polyelectrolytes.
These are long chain polymer molecules with
higher charge density. They help form larger floc
which settles faster.
Unlike inorganic coagulants they do not decrease
the pH of the treated water nor increase the TDS.
Sedimentation refers to the physical removal from
suspension or settling that occurs once the
particles are coagulated and flocculated.

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JSW Energy Ltd
Coagulation
Finely divided suspended particles in water repel
each other because most of the particles are
negatively charged .The coagulants neutralize the
charge and also hydrolyze to form insoluble
precipitates. pH plays an
important role
Accomplished by inorganic salts of Aluminium and
Iron
or by organic polymers
Al2(SO4)3 + 6NaHCO3 =2 Al(OH)3+3Na2SO4+6CO2
Best coagulation in pH range 6 - 7

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Inorganic Coagulants
Al2(SO4)3 + 6NaHCO3 = 2Al(OH)3 ¯ + 3Na2SO4 +
6CO2
pH 6-7
Fe2(SO4)3 + 6NaHCO3 = 2Fe(OH)3 ¯ + 3Na2SO4 +
6CO2
pH 5 -11
Na2Al2O4 + 4H2O = 2Al(OH)3 ¯ + 2NaOH
pH 7-9
1 ppm of alum adds0.45 ppm of sulfate ion as CaCO3

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JSW Energy Ltd
Polyelectrolyte
They are water soluble organic polymers used in
Clarification.
Low molecular weight(<500000) polymers used for
primary Coagulation
High molecular weight polymers are used for
flocculation

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JSW Energy Ltd
Types of poly-electrolytes
Anionic: ionize in water to form negatively charged
sites along the polymer chain. It is a copolymer of
acrylamide and acrylic acid
Cationic: ionize in water to form positively Charged
sites along the polymer chain. It is a copolymer of
acrylamide and acrylic acid
Nonionic: ionize in water to form slightly negatively
charged sites along the polymer chain.It is
basically
polyacrylamide

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JSW Energy Ltd
Chlorine, Sodium hypochlorite Ozone etc. are some
of the chemicals used for Oxidation
Cl2 + H2O = HOCl + H+
+ Cl-
Ozone is a powerful oxidizing agent but requires on
site generation equipment

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The Three processes happening in a clarification
equipment are
- Rapid mix for coagulation
- Moderate mixing for flocculation and
- Floc and water separation.
The most common design is the upflow clarifier
where the water flows up while the floc settles.The
two types are
- Sludge blanket type and
- Solids contact type
Both utilise part of the settled floc to enhance
sedimentation
Clarification

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Removes bulk of turbidity & sediment. The particles
with a settling velocity exceeding the upward
velocity of the fluid settle out and are separated
STOKES LAW
Vs = g(ρs –ρl)d2
------------------
18μ
Vs is terminal settling velocity m/s
g is acceleration due to gravity m/s2
d is particle diameter m
ρs, ρl density of particle, liquid,Kg/m3
μ is liquid viscosity Pa.S

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JSW Energy Ltd
Clariflocculator
"Solids-contact" refers to units in which large
volumes of sludge are circulated internally. The term
also describes the sludge blanket unit and simply
means that prior to and during sedimentation the
chemically treated water contacts previously
coagulated solids.

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Clarifier JSW Steel Ltd

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The efficiency of coagulation – flocculation is increased
by repeated soilids contact.
The sludge formed in the Process is utilized to contact
the coagulated –flocculated water and increase the
probability of collisions resulting In better flocculation.
High rate solids contact clarifiers work on this principle

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JSW Energy Ltd
Solids contact Clarifier

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JSW Energy Ltd
Filtration
Used to remove any remnants from clarification
process brings down turbidity from 10-20 NTU to
0.5 – 2 NTU.If raw water has less turbidity, directly
filtration can be applied.
It is a separation process where in solid liquid
mixture is passed through porous media which
retains solids and allows liquid to pass through.
During filtration the retained solids gradually build
up and block the interstices of the filter media and
cause head loss.

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Gravity filters – Pressure filters
Down flow filters – Up-flow filters
Automatic gravity filters
Filter washing gravity filters
Pre coat filters
Self cleaning filters
TYPES OF FILTERS

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Gravity Sand filter

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Pressure sand filter

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JSW Energy Ltd
The filter needs to be back washed :
Once the head loss reaches a preset value
The treated water turbidity deviates from the preset
value
Back wash is performed using
1.Air and Water simultaneously
2.Air and water in succession

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The different types of filter media used are
Quartz sand
Anthracite
Dual media of sand and
Anthracite / garnet
Multi media of sand, anthracite
Garnet, Granular activated carbon (GAC)
Typical filter media is 15 -30 inch deep bed.
Dual media filters allow high filtration rates, require
Less back wash water than stand alone filters
GAC additionally removes organics and free chlorine
FILTERMEDIA

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JSW Energy Ltd
DEMINERALIZATION
The process of removing the dissolved solids from
Water is known as Demineralization
This is accomplished at JSW Energy by using
Ion Exchange Process

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JSW Energy Ltd
DM Plant Flow
Diagram
DMF
Degas blower
Degas water
Storage
Tank
Raw water tank
SAC
DM STORAGE
TankSBA
Mixed
Bed
UF STORAGE
Tank
UF

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JSW Energy Ltd
Dual Media Filter
Carbon steel vessel containing Sand & Anthracite
Capacity :45 m3/hr
Anthracite Qty : 1.64m3, 0.508 m depth
Size of Anthracite : 0.9 – 1.0 mm
Sand Qty :2.07 m3, 0.405 m depth
Size of sand : 0.45 – 0.55 mm
Turbidity Inlet water : <20 NTU
Turbidity Outlet water : <2 NTU

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Ion Exchange Resins
Made by co polymerization of Styrene cross
linked with
Di-vinyl Benzene. Ion exchange resins exchange
one ion
for another, hold it temporarily and release it to a
regenerant solution.
New forms of resins with acrylic structures are
also available with more resistance to organic
fouling
In addition to plastic matrix ion exchange resin
has ionizable functional groups. This contains one
mobile and one immobile Radical. Mobile radical
is exchanged

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JSW Energy Ltd
Strong Acid Cation Resin (R-SO3.H)
SAC has sulfonic acid (HSO3) functional group
Converts neutral salts into respective acids
Ca 2(HCO3) Ca
2H2CO3
Mg SO4 + 2RSO3.H = 2RSO3. Mg +
H2SO4
2Na 2Cl 2Na
2HCl
The exchange reaction is reversible. When
capacity
Is exhausted the resin is regenerated with excess

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Strong acid Cation Resin

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SAC is a rubber lined carbon steel vessel with inlet
distributor, regenerant distributor, ion exchange resin
free board space and resin retaining under drain
system
Resin is retained using strainers which allow only
water to flow and prevent resin
The volume of resin employed depends up on
capacity of resin and salanity to be removed
Selectivity for cation exchange
Ca > Mg > Na

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JSW Energy Ltd
ION EXCHANGE VESSEL INTERNALS

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STRAINERS

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JSW Energy Ltd
Strong acid cation is regenerated when
1.Designed quantity of water is processed
OR
2.Sodium content in outlet water is more than design
usually >1 ppm
OR
3.Conductivity comparator reading crosses stipulated
value

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Regeneration
Co – flow Counter flow
Service Regeneration Service Regeneration
Counter flow results in
High quality out put, better regeneration efficiency
Requires down flow water to keep resin bed intact

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JSW Energy Ltd
Hydrochloric acid Regeneration 4 – 5% HCl
Sulphuric acid Regeneration H2SO4
Step 1 : 1.5 – 2 %
Step 2 : 3 %
To avoid Calcium Sulphate precipitation
Regeneration

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Degasser Tower
Water Inlet
Air Inlet
Air Vent
Water Storage
Packing

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De carbonator works on the principle of Henry’s
law
Solubility of any gas in liquid is directly
proportional to the partial pressure of gas at the
liquid surface
C total = K P
C total : total concentration of gas in solution
P : Partial pressure of gas above solution
K : constant

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Hence a dissolved gas can be removed from solution
By lowering the partial pressure of the gas above
solution
This can be done by
1. Vacuum is applied over the system and unwanted
gas is vented
2. A new gas is introduced and unwanted gas is
vented

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Strong Base Anion
Strong base anion has quarternary ammonium
Functional group and is used in hydroxide (OH-
) form
CH3
l
(R – N – CH3)+
. OH-
l
CH3

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JSW Energy Ltd
In hydroxide form SBA can remove all anions
commonly encountered
H2SO4 SO4
2HCl 2Cl
2H2SiO3 + 2R.OH = 2R. 2HSiO3 + 2H2O
2H2CO3 2HCO3
The reactions are reversible and once exhausted
The resin can be regenerated with sodium hydroxide
to return to hydroxide form
The selectivity for anion exchange
SO4 > Cl > HSiO3

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Treated water quality parameters for SBA
pH 7.5 to 8.5
Conductivity < 6.0 μ s/cm
Silica < 0.1 ppm

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Strong base anion is regenerated
1.When designed quantity of water is processed
OR
2.Silica content in treated water goes beyond limits
OR
3.Conductivity of treated water increases beyond limits
& pH of treated water is lower then limits
Regeneration is carried out using 4% Sodium hydroxide

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JSW Energy Ltd
MIXED BED
As the name suggests it consists of both Cation and
Anion Resins. This is a polishing unit and is the last
stage of Demineralization process to get final quality
DM Water.
The two resins are in thoroughly mixed state in service
condition and are separated for regeneration using
Back wash
After back wash Cation resin settles at the bottom
and Anion resin remains at top due to density difference
Blocking flow arrangements are designed to prevent
entry of regenerant chemicals into other resin during
regeneration

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Treated water quality after Mixed Bed
pH 6.5 to 7.2
Conductivity <0.1 μ s/cm
Silica < 0.02 ppm

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JSW Energy Ltd
Mixed bed is regenerated
1.When designed quantity of water is processed
OR
2.Silica content in treated water goes beyond limits
OR
3.Conductivity of treated water increases beyond limits

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JSW Energy Ltd
ULTRA FILTRATION
Ultra filtration is a membrane process in which higher
molecular weight solutes are concentrated from feed
stream
In JSW Energy it is employed to remove colloidal
Silica which can not be removed in Ion exchange
process.
Colloidal Silica removal efficiency > 95%
Ultra filtration membranes are hollow fiber membranes
made of
Polysulphone (PS)
Polyethersulphone (PES)
Polyvinylidenefluoride (PVDF)

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UF Hollow Fiber Membrane

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The filtration system is inside out cross- flow filtration
Fast flush : In this water will flow in the same
direction as in service with higher flow rate membrane
Gets pressurized and adhered material gets dislodged
Back flush: In this water flows in opposite direction to
Service cycle. This takes away the remaining dirt after
Fast flush

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JSW Energy Ltd
DMT
Fast flush pump
Feed pump
Pre-filter
UF MODULE
Back flush pump
UFT
UF PERMEATE
Reject To CW Forebay
To Neutralizing pit
Cleaning tank
UF SCHEMATIC

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Thank You