Water Treatment Seminar: Cooling Towers, Chillers, pH and More

Water Treatment
Seminar
Cooling Towers & Chillers

Presented by International Chemtex P.R.Inc.

Water Treatment Seminar
Things you will learn in this seminar
 Properties of Water
 Hydrogen Bond
 Specific Heat of Water
 Water as a Coolant
 Water as a Solvent

 Meaning of pH
 What is an acid ?
 What is a base ? ( Alkalinity)
 Effect of pH on solubility

 Chiller Plant Operation
 How Chillers Work
 How Cooling Towers Work

 Problems associated with Cooling Water
 Scale/ Deposits: Causes & Prevention
 Corrosion: Causes & Prevention
 Different Types of Corrosion
 Fouling: Causes & Prevention
 Microbiological Fouling: Causes &
Prevention

 Overview of Chemical Equipment
 Cooling Tower Controllers
 Chemical Pumps
 Water Softeners
 Sand Filters

 Chemical Safety
 Explanation of MSDS
 Ten commandments of safe chemical
handling

 Testing Procedures
 Conductivity test using meter
 pH test using meter
 Hardness test to check softener
 Organo test to check residual of scale
inhibitor chemical in the cooling tower
 Nitrite test to check residual of corrosion
inhibitor in the chill loop system


Let’s get started…

Properties of Water

Water has a very simple
atomic structure. It has
two hydrogen atoms
bonded to one oxygen
atom.

Properties of Water

Each hydrogen atom has one
proton and one electron. The
oxygen atom has 8 protons and
8 electrons. Both hydrogen
atoms share their electrons
with the outer shell of the
oxygen. Note there are more
electrons on the oxygen side of
the water molecule than on the
hydrogen side.

Properties of Water

Due to the unique
geometry of the water
molecule, the hydrogen
side has a slight
positive charge. The
oxygen side has a slight
negative charge.

Properties of Water

This molecular polarity causes water to be a
powerful solvent and is responsible for its
strong surface tension.

Properties of Water
This polarity of charge
causes molecules of
water to be attracted to
each other in a strong
molecular bond called
the “hydrogen bond”.
Water molecules can
bind together in
chains.

Properties of Water
 Due to the hydrogen
bond, water has a
high “specific heat”.
 Specific heat is the
amount of energy
Water as ice has a highly required to change
organized structure. It takes the temperature of a
large amounts of heat to make substance.
a phase change to liquid water.

Properties of Water
 Water in the liquid
form remains as a
liquid over a wide
temperature range
from 0 C to 100 C.
 Because water can
As ice is heated and melts to
form water, the water mole-
absorb so much heat
cules move apart and become and still remain a
more energetic. But the hydro- liquid, it makes a
gen bond keeps pulling them good “coolant”.
back together like rubber bands.

Properties of Water
 Once enough heat is
applied, water can
make another phase
change and turn to
steam. Notice the
water molecules as
Water molecules as steam have steam have become so
enough kinetic energy to break energetic they have
away from the hydrogen bond broken away from the
binding it to other water mole- hydrogen bond and
cules. now are separate
atoms.

Properties of Water
 Another property of
water caused by the
hydrogen bond is the
strong surface tension
of water.
 Water can overfill a
cup because the water
underneath pulls
down on the surface
water.

Properties of Water

The strong surface
tension of water
allows for the
formation of
water droplets and
waves.

Properties of Water
The diagram on the left
is that of a salt
molecule. Salt is made
of sodium & chloride
atoms.

Properties of Water
When salt is dropped into
water it dissolves. The
positive regions of each
water molecule is
attracted to the
negatively charged
chloride atoms.
Conversely the negative
area of each water
molecule is attracted to
positively charged
sodium atoms.

Properties of Water
Water will dissolve
different minerals, for
example calcium. The
calcium atom has a
positive charge. The
negative side of each
water molecule is
It takes many water molecules to keep attracted to the positively
just one calcium molecule in solution. charged calcium atom.
Calcium’s atomic number is 20 but
Oxygen’s is only 8. So the calcium
atom is 2.5 times bigger than the
oxygen atom.

Properties of Water

Water is called a
universal solvent, but
each volume of water
has a saturation limit.
 Once any mineral has
reached its saturation
limit in a given
volume of water, no
more mineral can go
into solution.

Properties of Water
 Once the saturation limit
has been reached, any
additional mineral
added to the water will
fall out of solution.
 In cooling water, calcium
will precipitate to form
hard scale deposits in
chiller tubes and towers.

Properties of Water
 Each mineral has a distinct saturation limit in water
which depends on certain factors.
 Calcium is the main scale forming mineral in cooling
tower waters.
 Calcium’s saturation limit is affected or changed by
factors such as the level of calcium hardness, pH,
temperature, and alkalinity of the cooling tower water.
Once the calcium saturation index has been exceeded,
then the excess calcium will precipitate out of solution
and form scale deposits in the heat exchange areas of the
chiller system, namely the chiller tubes and the tower
fill.

Meaning of pH
Water in a pure state
has a neutral pH.
Water changes its
pH when substances
are dissolved in it.
The pH scale is used
to measure the
acidity or alkalinity
of a substance.

Meaning of pH
An acid is any chemical compound that, when
dissolved in water, gives a solution with a hydrogen ion
activity greater than in pure water, i.e. a pH less than
7.0. An acid will range from 0 to 7 on the pH scale.

A base can be thought of as the chemical opposite of
an acid. A base will range from 7 to 14 on the pH scale.
Bases and acids are opposites because the effect of
an acid is to increase the hydrogen ion (H3O+)
concentration in water, whereas bases reduce this
concentration. Bases react with acids to produce water
and salts.

Meaning of pH
For Example:

Acid + Base = Water + Salt

ACID: HCl is Hydrochloric Acid
BASE: NaOH is Sodium Hydroxide

When you combine: HCl+NaOH = H20 + NaCl
This is Water & Salt

Meaning of Ph
The pH of cooling
tower water is
important to us
because the pH will
change the solubility
of calcium in water.
Lower the pH and
more calcium can stay
in solution. If pH is
too alkaline, calcium
will fall out of
solution.

Chiller Plant Operation

Chiller & Cooling Tower work together
to cool interior of the building

 Chiller cools chill water
down to 40 degrees, then
circulates chill water to the
building. Return chill
water comes back at 50
degrees and causes Freon
gas to evaporate.
 Condenser water cools
down Freon gas.
 Compressor turns Freon
gas back to liquid ready to
Tower water enters condenser at repeat the cycle.
85 degrees but leaves condenser
at 95 degrees and returns to tower.

 Purpose of the cooling
tower is to eject heat and
cool down the condenser
water by 10 degrees.

 By cooling the water, the
same water can be used
again and recycled to the
condenser. This saves
large amounts of water.

 Cooling Towers cool water
via the process of
evaporation.

 The tower water is broken
up into droplets and air is
passed through the falling
water. Every minute 1% of
the tower water evaporates
but the other 99% is cooled
down by 10 degrees and is
recycled to cool the
condenser. This process
repeats constantly.

Notice the condensation
of the evaporating
tower water. The
evaporation process
cools down the
remaining tower water
but leaves mineral
impurities behind.

These mineral impurities in water takes us to our next subject,
Problems in Tower Water; the reason we need water treatment.

Problems in Tower Water
There are four main problems which occur
in cooling tower water :
 Scale

 Corrosion

 Fouling

 Microbiological Fouling

 The first problem in tower water is:

Scale

 As we have seen, water
is a good solvent.
Tower makeup water
has mineral impurities
in it like, calcium,
magnesium & silica.
 These minerals left
unchecked can cause
scale deposits to form
on condenser tubes.

 Scale will form on chiller tubes
if mineral saturation level is
exceeded and scale inhibitor
residual falls too low in the
tower water.
 Scale on tubes will increase
energy costs by 10% to 30%
depending on thickness.

 Preventing scale is one of the
main objectives of the water
treatment program.

 The dissolved solids in tower
water if left to concentrate to
high levels will also form
scale deposits in the cooling
tower fill and in the louvers.

 This may require expensive
down time cleanouts.

 Scale is prevented by:

 The proper amount of bleed off

 And the addition of chemical scale
inhibitors to the tower water which
prevent scale formation.

 Proper amount of bleed off limits
the concentration of mineral
solids

 Tower water is bled to drain
before the saturation limit on the
scale forming mineral is exceeded

 The exiting bleed off water
contains a high level of dissolved
solids ( minerals) and is replaced
with fresh water which has a
lower level of solids

Bleed off alone can not
prevent scale
 Scale inhibitors must be
added to the tower water
and maintained within
desired ranges at all times
 Bleed off and injection of
chemicals is done
automatically with proper
chemical equipment


 The chemical scale inhibitors we use to treat
the tower water have two main properties:

 Crystal Distortion

 Dispersancy


 Crystal Distortion
 Polymers distort the crystal growth of the scale by disrupting
the crystalline lattice which causes the hard dense adherent
nature of scales. With the inclusion of a relatively large,
irregularly shaped polymer in the crystalline lattice, scale
does not develop or adhere to surfaces where it could cause
heat transfer problems.


 This is an electron
microscope photo of
calcium carbonate
crystals.
 Note the regular
structure of the crystal,
almost like building
blocks.


Once the water is
treated with polymers,
which distort the
crystalline structure, the
calcium can no longer
adhere and build up
scale deposits.


 Dispersancy
 Polymers are used for dispersing particles so they do
not tend to settle. Anionic polymers are effective
dispersants because they will increase the negative
charges of particles causing the particles to repel
each other and more easily keep them in suspension
so they can be removed by normal bleed off.

 The second problem in tower water is:

Corrosion

 Corrosion can be
caused by many
factors.

 If acid is added to tower
water to help maintain
calcium hardness in
solution, an overfeed of
acid can cause severe
corrosion in the
condenser.

 Acid Feed Primer:
Adding acid to the tower water lowers the pH
and increases the solubility of some scale
forming minerals. For example adding sulfuric
acid changes calcium carbonate ( the main scale
forming mineral present in tower water) to
calcium sulfate, which has a much higher
solubility index than than calcium carbonate. An
overfeed of acid can result in severe corrosion
even catastrophic system failure.

 To avoid the potential for this
type of corrosion, we
recommend not to use an acid
feed to control scale forming
impurities.

 In high hardness waters where
acid feed is necessary, we prefer
to use a water softener and a
high quality polymer scale &
corrosion inhibitor chemical.

 There are other types of corrosion that can
occur in tower systems. Some examples are:
 General Corrosion
 White Rust on new galvanized cooling towers
 M.I.C. - Microbiologically Induced Corrosion
 Erosion
 Galvanic Attack
 Cavitation

 Corrosion may be prevented or mitigated by
the proper addition of corrosion inhibitors
and biocide chemicals.

 However; some types of corrosion can not be
prevented by chemicals. They must be
remedied by mechanical or other means.

 Generalized corrosion is caused by oxygen in the
water attacking the metal.
 This type of corrosion is reduced or mitigated by
adding corrosion inhibitors to the tower water.
 The inhibitor works by laying down a thin
protective film on the wetted metal surfaces in the
tower water piping system. This film inhibits the
oxygen from reaching the metal.

 The rate of generalized
corrosion can be monitored
by using corrosion coupons
 Metal coupons of steel and
copper are inserted into the
water stream for 60 to 90
days
 They are then removed and
analyzed for metal loss.

 No corrosion inhibitor will
completely stop all
corrosion. The idea is to
reduce the rate of corrosion
to acceptable limits.

 Acceptable limit for mild
steel is 2 mils per yr. Limit
for copper is 0.2 mils per
year

 White Rust is a type of
corrosion that can occur in
new galvanized towers.
 White Rust refers to the
premature, rapid loss of
galvanized coating on
cooling tower metal
surfaces.
 White Rust is evidenced
by a white, waxy buildup
on the surface of the
galvanized metal.


Once the
galvanized coating
has been removed,
the underlying
steel/iron rapidly
corrodes

Problem in Tower Water
 Why White Rust occurs is a little
complicated, but there are 3 main reasons:
 The imperfect manufacture of the galvanized
coating of the tower metal
 Lack of passivation when tower first started up

 Running tower with high alkalinity levels in
tower water
 Please refer to Chemtex Technical Topic on
White Rust for a more in depth analysis

 The next type of corrosion to discuss is:
M.I.C. - Microbiological Induced Corrosion

 M.I.C. is caused by bacteria, mostly by:
SRB- Sulfate Reducing Bacteria
IRB - Iron Reducing Bacteria

 SRB - Sulfate Reducing
Bacteria are anaerobic
(oxygen free) class of
bacteria that can thrive
under deposits of dirt and
silt in basin of towers.
 SRB form nodules that
cause pitting. This bacteria
can actually eat through
the basin of the tower
and/or piping and cause
leaks.

 SRB - Sulfate Reducing
Bacteria are usually found
in low flow areas of the
tower system, like in the
tower basin.

 Nodules are formed under
dirt or other aerobic
bacteria debris. These
nodules start a reaction
that leads to pitting.


 These are active SRB nodules in the cooling
tower basin.

 IRB - Iron Reducing
Bacteria are aerobic ( need
oxygen) class of bacteria
which feed on iron.
 IRB removes iron from the
water and/or the piping
and deposits it into sticky
secretions.
 IRB can cause pitting and
plugging. IRB can form
tubercules inside piping
reducing water flow.

 Erosion
 Sometimes in the tower, corrosion of the metal is
caused by erosion. If sand or dirt particles are
present in the air around the tower, the
movement of air thru the tower can scratch the
surface metal, removing the protective
galvanizing thus opening up the underlying
steel/iron for rapid corrosion.

 Please note the corrosion inhibitor can only work
on fully wetted surfaces. In the tower the
corrosion inhibitor can not protect any metal
above the water line.

 It should be obvious that erosion corrosion
occurring in the tower cannot be prevented by
chemicals. Unfortunately the addition of the
proper chemicals and good control of the
chemistry will not prevent some types of
corrosion.
 Don’t fall into the “Flag Pole Syndrome”…
If the flag pole in front of the building falls
down, call the water treater cause it must be
his fault :)

 Galvanic attack is type of corrosion which can
occur in cooling tower piping systems.
 If two dissimilar metals are connected in the
presence of an electrolyte (water), they act as a
short circuited galvanic cell and corrosion will
occur.
 The farther apart the metals are on the
galvanic series the greater potential for
corrosion.

 The anode (negative)
metal is giving up
ions to the cathode
(positive) metal.
 The results is
corrosion and pitting
in the anode metal.


The higher the dissolved solids level in the
water, the higher the potential for corrosion


 Corrosion starts when two dissimilar metals such as galvanized
pipe (anode) is joined to a metal like copper (cathode) in an
electrolyte (water).
 Corrosion can occur at the anode metal causing pitting.

 On the galvanic series,
copper is on the cathodic
end of the range and
zinc (galvanized) is
close to the top of the
anodic range.
 When these two metals
are joined together, there
exists a high potential
for galvanic corrosion.

 These photos show
galvanic corrosion when
a galvanized pipe is
attached to a copper
pipe.
 If a small section of
galvanized pipe is
connected to a large
section of copper pipe,
then the cathodic area
will begin to corrode.

 Galvanic corrosion can not be prevented by
chemical treatment.
 Mechanical measures need implementing to
prevent galvanic attack.
 Avoid installing dissimilar metals
 Insert di-electric couplings between metals

 Reduce conductivity of the electrolyte
 Pure water will poorly conduct an electrical current

Problems with Tower Water
 Cavitation is another type of corrosion which
can occur in cooling tower water piping
systems.
 Cavitation occurs when gas bubbles trapped in
the circulating water enter an elbow or make a
turn and the pressure in the water changes
rapidly. The gas bubbles can expand making
microscopic gouges in the metal.
 Over time these gouges, erode away the metal.
 This is called Cavitation-Erosion.

 The drawing shows
the turbulence of the
gas bubbles
expanding & making
gouges in the metal.

 These two photos show
the cavitation-erosion or
impingement in the
elbow of pipes.

The damage is done after
the elbow in the area
where the gas expands
rapidly after making the
curve.

 This type of corrosion can
only be prevented by
mechanical means and
not by chemicals.

 Cavitation-erosion can
occur inside chiller tubes
where baffle supports
hold the tubes.
 If support pinches the
tubes, gas bubbles in
water can expand to
create turbulence and
gouge metal inside
chiller tubes.

 Vibration at the
baffle support area
can also lead to metal
fatigue and corrosion
resulting in leaks in
the chiller tubes.
 Not all types of
corrosion can be
prevented by
chemicals.

 Corrosion Section Summary
 We have reviewed some of the more common
corrosion problems to occur in cooling
systems.
 However, be aware there are other types of
corrosion which can occur. Time does not
permit us to mention them all.
 When corrosion does occur, the relative data
needs to be collected, studied and analyzed
before causes and cures can be assigned.

 The third problem in tower water is:

Fouling

 Fouling is caused by dirt and other
suspended solids in the cooling tower
water accumulating in the tower basin
and migrating to the chiller tubes.


 This photo shows the
accumulation of sludge
buildup in the tower
basin.
 This dirt/mud/silt
buildup is called
fouling and has several
sources.

 Sources of Fouling are:

 Suspended solids (dirt) in tower water makeup. Sometimes, the
makeup water ( especially after a heavy rain) comes with a high
amount of suspended solids ( dirt).

 Air borne dirt entering the tower. Cooling towers act like air
washers; any dirt in the air gets sucked into the tower and can
settle out in the basin of the tower. Some of this dirt can travel to
the chiller causing fouling inside condenser tubes.

 Accumulations of dead algae & bacteria in tower basin and piping.

 Suspended Solids are different than dissolved solids. The dissolved
solids in tower water which concern us are the scale forming minerals
like calcium. Dissolved solids are at the molecular level and must be
treated with chemicals.

 Suspended solids are the dirt and silt in the tower water you can see
with your eye. Suspended solids are many thousands of time larger
than dissolved solids.

 Some success can be achieved using chemicals like anionic
dispersants to remove suspended solids from the tower water system.
At times it is necessary to remove the suspended solids from the
tower water by mechanical means, by filtering the water via a sand
filter. Sand filters will be discussed in the “Equipment Overview”
section later in this presentation.

 The fourth problem in tower water is:

Microbiological Fouling

 Microbiological fouling refers to fouling
that occurs when algae, bacteria and
fungus grows out of control in cooling
tower systems.
 This type of fouling can plug strainers,
which reduces water flow to chillers.

 Algae & bacteria can
grow unchecked in
tower water and cause
fouling in the tower
basin and inside the
condenser tubes.
 Fouled tubes increases
energy consumption &
can cause unscheduled
shutdowns.

Problems with Tower Water
 To prevent
microbiological fouling of
the tower and chiller
tubes a good dual biocide
feed program must be
used at all times.

 Tower should be visually
inspected weekly and
bacteria dip slides run to
insure bacteria counts are
under control.

Discussion of Biocides:

 Biocides are the chemicals that kill and control
the growth of algae, bacteria and fungus in open
cooling tower water systems.
 Biocides are usually slug fed to the tower.
 There are different classes of biocides. Some are
oxiziders, like chlorine, and are slightly
corrosive to use. While others are non-oxiziders
and are non-corrosive.

Discussion of Biocides continued:

 Different biocides have different mechanisms
or ways to kill the organisms.
 Oxidizing biocides strip or burn thorough the
cell wall thus exploding the bacteria.
 Non-oxidizing biocides control organic growth
by preventing the bacteria from absorbing food
or reproducing.


 Some biocides, due to the way they work, are
excellent at killing algae but only average in
killing bacteria.
 Conversely, other biocides are great at killing
bacteria but only average to poor at killing
algae.
 Some biocides do not work well in high
hardness or high alkaline waters.


 The proper selection of biocides will depend on
several factors such as what type of organism
you are trying to kill and control and what is the
chemical qualities of the tower water you are
treating.
 It is important to use dual alternating biocides
to insure no organism develops an immunity to
a single biocide used constantly.

 Improper water treatment
and/or lack of control will
result in fouled chiller tubes
and dirty towers costing
thousands of dollars in
excess energy and clean out
expenses.
 A good, well controlled,
water treatment program
will prevent these problems
from occurring.

Chemical Equipment Overview

 Chemical Equipment Review

1. Cooling Tower Controllers
2. Chemical Feed Pumps
3. Water Softeners
4. Sand Filters

 Photo shows a typical
chemical equipment
installation.
 It consists of:
 tower bleed controller
& solenoid valve for
bleed off
 one scale inhibitor
pump
 two biocide pumps for
dual biocide feed

QuickTime™ and a
decompressor
are needed to see this picture.

Schematic of Chemical Equipment Installation

 The main purpose of the
bleed controller is to
monitor via a electronic
sensor, the conductivity of
the tower water.
 Once the conductivity set
point has been reached, the
controller sends a signal to
the bleed solenoid valve to
open.
 Tower water is bled to drain
replaced with fresh makeup
water.

 The tower controller also
controls the operation of the
three chemical pumps.
 The scale inhibitor pump is
programmed to come on
once every 30 minutes for a
few minutes to inject the
scale inhibitor chemical.
 Each biocide pump only
comes on once a week for a
preset time to slug feed a
dose of biocide to the tower.

 All settings on the controller
are programmed by the
Chemtex technician.
 All functions work
automatically without the
need for the plant’s
personnel to do anything.
 However, from time to time
the controller may lose some
calibration on the
conductivity reading. If &
when this happens, the
Chemtex technician will re-
calibrate the controller.

 Water Softener.
 The purpose of the
softener is to remove
the calcium &
magnesium hardness
from the tower
makeup water.

 A water softener consists
of a mineral tank that
holds the resin and a brine
tank that stores the salt.
 It also has a control valve
and a timer that initiates
and controls regeneration.
 Once the resin bed is
exhausted, the
regeneration cycle starts.

 When softener tank is
online, hard water
enters the softener and
passes down through
the resin bed.
 Ion exchange takes
place with the calcium
& magnesium ions
sticking to the resin
and releasing sodium
ions in their place.

 Calcium & magnesium are scale forming ions.

 The sodium ion is non scaling. Sodium will stay
in solution hundreds of times more than calcium.

 Replacing the calcium and magnesium ions for
sodium makes the water soft ( non scaling).

 The softener ion
exchange resin looks
like tiny beads.
 Once all the resin
beads are saturated
with calcium, the
resin bed must be
recharged with salt
 Salt is NaCl (sodium
chloride).

 Recharging the resin bed with salt is called
regeneration.
 During regeneration the control valve passes the
softener through 4 stages.
 During regeneration, salt ( sodium) is passed
across the resin. Ion exchange takes place again.
 Now the sodium sticks to the resin and the
calcium & magnesium are released and flushed
to the drain.

The four stages of regeneration are:

1. Backwash
2. Brine Draw
3. Slow Rinse
4. Fast Rinse

 Before regeneration starts
the softener is in the
normal service mode.
 The hard water enters
from the top passes down
through the resin.
 Ion exchange takes place.
 Soft water exits softener
and goes out to service.

 During the first stage of
regeneration the softener
enters the backwash
mode.

 The water enters from the
bottom passes up through
the resin then out to drain.

 Backwash removes the
dirt from the resin.

 During the second stage of
regeneration the softener
enters the brine draw
mode.
 The salt water enters from
the brine tank and passes
down through the resin
then out to drain.
 Brine draw releases the
calcium & magnesium
from the resin and flushes
it to drain.

 In the third stage of
regeneration, once the
brine tank is empty, the
softener goes into the
slow rinse mode.

 During slow rinse the
excess salt water is
slowly rinsed or purged
from the mineral tank
and flushed to the drain.

 In the fourth stage of
regeneration, the softener
goes into the fast rinse
mode.
 During fast rinse water is
rapidly passed across the
resin to remove any last salt
left in mineral tank from
the brine draw.
 After fast rinse, the softener
is returned to service or
placed in standby ( if a twin
unit).

 In a twin alternating water softener systems, one tank is
in service and one tank is on standby. When the unit
online goes into regeneration, it goes offline and the
standby unit goes into service. Thus soft water always
goes out to the system.

 In a single tank unit, when the mineral tank goes into
regeneration there are two options:

 Hard Water Bypass- While the unit is in regeneration, hard
water by-passes the softener and goes out to the system.

 NO Hard Water Bypass- While the softener is in regeneration,
NO water goes out to the system.

 Sand Filter

 While the sand filter is not a piece of chemical
treatment equipment, it does help us achieve the
goals of the water treatment program.

 Sand filters by eliminating the sludge buildup in
the tower basin, prevents fouling.

 When a sand filter is installed on a tower there is little or
no buildup of dirt in the tower basin. This makes the
biocide/ chemical program more efficient.

 Less biocide/ chemicals are used. When a tower is
fouled with sludge deposits, this layer of dirt gives a
place for the bacteria to hide and prevents the biocide/
chemicals from penetrating down through the dirt and
completing killing all the algae and bacteria. The
remaining bacteria quickly re-infect the tower water
system.


These are photos of typical sand filters installed
on cooling towers


This is a cut away view of the sand filter. The
sand only fills up 2/3 of the vessel.

 When in service mode, the water in a sand filter
flows from the top to the bottom. The space
between the sand is only 5 microns. The dirt gets
trapped between the sand particles. As the sand
filter becomes dirty it actually filters better and
better but the outlet flow starts to diminish.
 When flow is reduced, the filters’ back pressure
goes up. The pressure sensor on the filter senses
this and automatically puts the filter into the
backwash mode for 2 to 3 minutes.

 In backwash, the flow is reversed from the
bottom to the top of the filter. The sand bed is
uplifted. Because the dirt trapped between the
sand is lighter than the sand, the dirt is shaken
loose and flows up and away to the drain.
 The water flow up through filter in the backwash
mode is controlled so that the sand media is
slightly uplifted but not enough to wash the sand
up and over to the drain.
 After 2 minutes of backwash, the sand filter is
then again put back into the service mode.


The sweeper piping installation in the tower basin improves
operating efficiency of the sand filter. Sweeper jets push the
dirt to center of the tower towards suction piping of the filter.


Sand filters come in different sizes, from small, medium and large

Safety Guidelines
 The next section of our presentation is
called:

Safety Guidelines

Safety Guidelines
What is a MSDS ?
 MSDS stands for Material Saftey Data Sheets.
 MSDS give the following types of information:
 Identifies the chemical and lists hazard ingredients
 Lists the health hazards to personnel who handle any specific
chemical product
 List protective equipment personnel should use while handling
the chemical
 Lists the First Aid measures to give in case of accident
 Gives instructions on preventive measures in case of a spill or
leak

Safety Guidelines
 In your handouts are copies of MSDS on all
chemical products Int’l Chemtex supplies to this
site.
 While Chemtex employees usually handle and
place all chemicals online and refill drums, if you
handle any of these chemicals or if there ever is a
leak or spill,please refer to the appropriate MSDS
and follow the instructions.

Safety Guidelines
The next series of slides are called the:

10 Commandments of Handling Chemicals

We will discuss each slide as we go along.

Testing Procedures
Testing Procedures

In this section you will
learn how to run tests to
check for the chemical
residuals in the tower
and chill water systems.

Testing Procedures
 You will learn how to use
the conductivity meter.
 The meter is used to check
level of dissolved solids in
the tower & chill water.
 Using the meter double
checks the operation of
bleed controller & insures
the controller is calibrated
and working correctly.

Testing Procedures
 You will learn how to use
the pH meter.
 The pH meter is used to
check pH level of the
tower & chill water.
 At this site you may also
need to check the pH of
the tower effluent.
 The pH meter can verify if
tower pH controller is
properly calibrated.

Testing Procedure
 The next three tests are done using
reagents. These tests are:
 Hardness Test
 Checks for level of hardness in softener effluent
and in the tower and chill water
 Organo Test
 Checks for the residual of the scale inhibitor
chemical present in the cooling tower water
 Nitrite Test
 Checks for the residual of the corrosion inhibitor
chemical present in the chill water

Testing Procedures

 Please refer to your
handouts for the
instructions for each
test.

 This ends our water
treatment seminar.
 Congratulations ! You
are now graduates of a
Water Treatment
Seminar.
 Now put you new
knowledge to work.
 Thank you for your
attention !

Water Treatment
Seminar
The End

Presented by International Chemtex PR Inc

Water Treatment Seminar: Cooling Towers, Chillers, pH and More

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