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The
Objective:
Maintain the highest purity of water with the
least amount of water waste and chemical use. Chemical use in cooling
towers leads to an ever-increasing TDS, which must be reduced by
eliminating water (blow down/bleed off), then refilling with raw/lower TDS
water. This is a “vicious cycle” that will never end unless one of the TDS
increasing culprits is eliminated or reduced: That being
“chemicals”.
The Problem:
Cooling Tower
water quality tends to be extremely poor. Cooling Tower traditional
treatment is based upon extreme chemical use only. This means that you,
the “water treatment professional” has a chance to create an entirely new
income base, and aid in environmental integrity &
responsibility.
I. Water Quality control is
difficult due to:
Evaporation rate
Environmental
contaminates
Extreme chemical use
II.
Chemical Dependence is promoted by an industry that
serves and maintains cooling towers.
Most cooling tower manufacturers
do nothing about recommending or selling treatment equipment along with
the towers. In most cases it’s left up to the end users to set up the
treatment method.
The cost of chemicals is lower on the front end than
water treatment equipment, but far higher based upon the on going nature
of the use.
III. Water Waste:
It’s
not uncommon to see a (IE) 3,000-gallon cooling tower continuously
draining and replenishing raw water just to lower TDS. This
ever-increasing TDS is contributed to a great degree by the chemicals that
are used for treatment.
Not only is there an extreme amount of
water being wasted on a daily bases, but the environmental impact from the
chemical laden wastewater is deplorable. This chemically laden wastewater
will eventually make into our lakes, streams, river, and ground water, and
is becoming the subject of more stringent EPA regulations.
- Bacteria/virus elimination/prevention
- Organic Build-up
elimination/prevention
- Blow-down reduction/elimination
- Bleed-off reduction/elimination
- Improved clarity.
- Scale reduction.
- Cooler running temperatures where scale is
inhibited or reduced.
- Reduction or elimination chemicals needed
for algae control.
All this with no regularly scheduled
maintenance on the ozone unit!
Principle of Operation:
Ozone is injected into the water flow created by a
separate circulation pump. This pump pulls the water from the towers sump
or basin and sends it to the ozone injection, contact tank, and
scale/filtration. Lastly, the treated water returns back to the sump or
basin.
The principle is to treat the water and
eliminate/reduce the:
- Scale forming minerals
- Organics
- Harmful microbes.
The clean water is then used to clean the entire sump,
basin, pipes, and peripheral equipment.
I. Ozone Injection:
Ozone
is injected it into the side stream flow. Oxidation starts to take place
immediately on microbes, organics, bacteria, and virus.
II. Contact/Mixing
Chamber:
A contact tank helps to further the ozone’s ability to
oxidize particles allowing them time to react prior to returning to the
system. As water flows down the Off Gas Tank, ozonated water rises and
mixes any gas in the incoming water.
III. Filtration, Scale Control,
Particle Removal:
Possibly the most important aspect of any water
treatment is the removal of the particles that have been oxidized. Without
this step, all you have done with the ozone is change the structure of the
particles by making them larger, insoluble, &/or heavier. This step is
necessary for systems that require scale control, and particulate
removal.
We are very careful not to construct
too large of an ozone unit to handle the bacteria, scale, and
algae.
The problem encountered at this point is
corrosion. If you carry too high of an ozone residual to de-scale down
line you stand a chance of creating a corrosive situation in the sump and
its adjacent equipment.
For this reason we have utilized existing water
treatment technology and equipment in conjunction with ozonation. The
result is a system that works without high maintenance, dangerous
chemicals, or costly corrosion.
How does the maximum service flow rate relate to the
total system flow rate?
It doesn't. It relates to the total
system gallonage. Our formula is: total gallons / 4-5 (turnovers per day)
/ 60 = gpm of the side stream system. This equals approx. 0.004 gpm/gal
(treatment gpm / system capacity). Therefore, it’s crucial that we know
the total water volume rather than the tonnage. Tonnage to gallon capacity
varies greatly per tower manufacturer.
What is the ozone dosage in grams/hr or
lbs/day?
Each ozonator produces a set ozone production in
gr/hr. The S1 = 1.2 gr/hr; 22HD = 2 gr/hr; 32HD = 3
gr/hr; 62HD = 6 gr/hr; etc. We convert the measurement to lbs/day when
over 24 gr/hr. The typical dosage is: 1 gr/hr to every 5 gpm of treated
water.
IE: 10 gpm side-stream ozone treatment system would
include
a
2 gr/hr ozonator (22HD).
Is the ozone flow controlled by the amount of
residual in the system or is it wired to the tower pump or system pump
control box?
We supply a timer/control box assembly that
controls the ozone unit and circulation pump. Operational time will depend
upon water and tower conditions. As the conditions improve the operational
time can be reduced.
Does the ozone system eliminate the
scaling?
Yes, we can design the ozone system to eliminate
hardness/scale that can build-up on the tower, piping, pumps, and
peripheral equipment. We us a combination of ozone + water softening to
eliminate the scaling. This affords a lower cost system by using a smaller
ozone unit. Our system is set so the water is not completely soft and will
not be corrosive.
Does the ozone system control
algae?
Yes, we can design the ozone system to eliminate
algae but this denotes a larger ozonator. Algae are plants with roots and
are quite resistant to ozone. We can use ozone only, or ozone + a slight
chlorine or bromine residual to eliminate algae. The ozone + chlorine or
bromine option affords a much lower priced system since the ozone unit
used will be much smaller.
Is it true that ozone systems create a corrosive
condition?
In the “old days” when ozone was first used on
towers corrosion became an issue. This was due to the over use of ozone,
or the excessive dosage injected. There are some companies that are still
convinced that more is better and ozone can do “everything”. This can lead
to costly corrosion problems.
Our philosophy is to use the ozone where it is best suited:
- Organic inactivation
- Bacteria, virus, microbe elimination/reduction
- Clarifying
- Odor control
For scale and algae control we utilize
tried-n-true water treatment equipment that has been successful in all
phases of the water treatment industry for over 50 yrs. This affords the
use of smaller and less expensive ozone equipment and avoids corrosive
conditions.
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