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Non-Chemical
Water Treatment Technologies |
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AquaMAX
II
Proven Science and Engineering!
SKASOL provides physical and
chemical water treatment programs.
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We have no ‘built-in’ prejudice for chemical or physical
solutions. Our primary goal is to provide the optimal
solution for our customers. SKASOL has continually
explored the many "non-chemical" water treatment devices
that enter the market place. To date, it is our opinion
they have been more smoke and mirrors than solid
science. The exception has been a system from overseas
that we investigated over two years. After 12 months of
piloting and monitoring in our lab and a review of
existing installations we have launched our system as
AquaMAX II. It has now proven to control scale, reduce
water usage, control microbiological growth and
corrosion.
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| The science of the mineral scale
formation process is mature and well understood. The
heat transferred to the circulating water shifts the
carbonate equilibrium causing the relatively soluble
calcium bicarbonates to become the insoluble calcium
carbonate. Since the reaction occurs at the heat
transfer surface, the calcium carbonate crystals tend to
stick to each other and form a tenacious bond while also
adhering to the metallic heat transfer surface. The
AquaMAX II system exploits the well-known science of
"Bicarbonate Hardness" to relieve circulating water of
the scale causing constituents. |
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Current Cooling Water Treatment
Strategies
The majority of today’s cooling water operating parameters
exist above the pH of 7.0 and commonly above 8.0. The chemicals
used today are designed to aid in scale prevention under those
constraints. The cooling water systems operate at or just above
the level of saturation of calcium carbonate. The control of
calcium carbonate deposition/precipitation is from CaCO 3
crystal modification induced by the
chemicals. The cooling water is ‘stressed’ to the point where
blowdown is minimized while calcium carbonate and other mineral
scales are prevented with the chemical treatment.
How does the AquaMAX II control the
scaling process?
Using a process that is similar to the lime softening
process, the water to be treated is circulated through a vessel
while being exposed to high pH areas. When bicarbonate hardness
contacts high pH zones, the precipitation of calcium carbonate
is naturally forced from the calcium bicarbonate (see graph at
right). The resulting precipitation accomplishes two objectives:
1) It reduces the level of saturation of calcium carbonate 2)
Calcium carbonate forms in the vessel that will be filtered
directly after formation. This process does not remove all the
calcium. The constant precipitation of calcium serves to keep
the level of calcium carbonate at or below the level of
saturation in the cooling water systems preventing calcium scale
formation. Small seed crystals created are removed with a filter
included with the AquaMAX II system.
Removing scale
electrochemically before your heat exchanger can create it!
In the lime softening process, all the calcium is not removed
but is substantially reduced. The same reaction results occur in
the AquaMAX II. In the AquaMAX II, the high pH areas are created
electrochemically with anodes and cathodes. The typical DC
circuit provides a low pH surrounding the anode surface while
the cathode surface becomes very high pH. The vessel itself is
the large cathodic surface, which encourages the precipitation
of the calcium in the carbonate form using the available
bicarbonates. As the water is continuously circulated through
the vessel, the reduction of the bicarbonates is constantly
occurring, much of which will adhere to the vessel wall. The
excess calcium carbonate that is formed as a result of this
process is removed via filtration, so a buildup will not occur
of the precipitated calcium in your cooling systems. In essence,
the continual conversion of the bicarbonate to carbonate form
and the removal of the calcium carbonate controls the scaling
process in your cooling systems.
Reducing water usage
There will still be required blowdown of the system water to
remove excessive TDS, though the volume of blowdown required is
typically only 25 -30% of the prevailing
chemically-treated system blowdown
volume. The savings in water & sewer costs will be substantial
when using the AquaMAX II technology while significantly
reducing or eliminating the need for
any additional chemicals. This technology should not be confused
with "zero liquid discharge" programs. When the scaling
potential becomes excessive, the AquaMAX II will ‘flush’ the
accumulated internal scale buildup from the vessel and allow a
proportionate amount of circulating water to rinse the vessel.
The flushing cycle accomplishes the same function as a blowdown
controller does on a typical chemically treated cooling water
system. The major difference is the level of cycled TDS is still
much greater with the AquaMAX II than with traditional
chemically treated systems.
Example: 10,000gpm recirculation rate
@15 ºF
Delta T
 
The AquaMAX II System has a dramatic impact on
the environment. The AquaMAX II System significantly reduces the
amount of water previously discharged from your cooling water
system to control mineral concentration.
Typically, the AquaMAX II can save up to 75% of the water
normally discharged. ISO 9000 & 14000 certified companies
utilize the AquaMAX II System to achieve the environmental
standards required for certification. Best of all, the reduced
water and chemical consumption will benefit EVERYONE!
Corrosion Control via Control of
Saturation Indices
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Though the circulating water will still contain some minerals,
those remaining minerals will be
permanently dissolved and will not cause further scaling
concerns. The remaining mineral content in the circulation water
will cycle to a desired pre-set level. The water with the
additional mineral content serves to reduce any potential
corrosion concerns by adjusting the saturation indexes away from
the corrosion tendency. Corrosion concerns are alleviated since
the water is not aggressively seeking to dissolve metal while
being treated with the AquaMAX II system. AquaMAX II will keep
corrosion rates below industry-accepted standards by safely
increasing the Saturation Indices. Corrosion monitoring can be
accomplished using corrosion coupons and the Corrator technology
which provides real time data on the corrosivity of the water
and the corrosion rate of specific metallurgy. |
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Eliminating Chemical and Retaining
Microbiological Control Mechanisms
If your facility is using a softener or acid
feed, there are additional worries about the failure of softener or
overfeed/storage of acid. The AquaMAX II system is designed to eliminate
the need for acids or softening. In fact, there are only a few locations
that need any chemicals to successfully treat their cooling water. The
AquaMAX II system will provide added protection to control bacteria,
algae, and slime growth in your cooling water. In the electrolysis
process, the anode produces a small but constant level of chlorine from
the chlorides in the water. This small amount of chlorine combined with
the electrical current itself provides sufficient reduction of microbes
to maintain the control of bacteria and algae in your cooling water
system. The amount of chlorine generated is not sufficient to
significantly impact the ORP so the corrosive effect of chlorine is not
seen .
Further, bacteria are also killed by the localized
high pH at the cathode of the vessel. It is not unusual to achieve
bacterial counts of <1000 cfu in cooling systems using AquaMAX II.
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