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Technologies for Scale and Hardness Control
Technology for improving energy efficiency
through the removal or prevention of scale.
The magnetic technology has been cited in the
literature and investigated since the turn of the 19th century, when lodestones and naturally occurring magnetic
mineral formations were used to decrease the formation of
scale in cooking and laundry applications. Today, advances
in magnetic and electrostatic scale control technologies have
led to their becoming reliable energy savers in certain applications.
For example, magnetic or electrostatic scale
control technologies can be used as a replacement for most
water-softening equipment. Specifically, chemical softening
(lime or lime-soda softening), ion exchange, and reverse osmosis,
when used for the control of hardness, could potentially be
replaced by non-chemical water conditioning technology. This
would include applications both to cooling water treatment
and boiler water treatment in once-through and recirculating
The primary energy savings from this technology
result from decrease in energy consumption in heating or cooling
applications. This savings is associated with the prevention
or removal of scale build-up on a heat exchange surface, where
even a thin film can increase energy consumption by nearly
10%. Secondary energy savings can be attributed to reducing
the pump load, or system pressure, required to move the water
through a scale-free, unrestricted piping system.
This Federal Technology Alert provides
information and procedures that a Federal energy manager needs
to evaluate the cost-effectiveness of this technology. The
process of magnetic or eletrostatic scale control and its
energy savings and other benefits are explained. Guidelines
are provided for appropriate application and installation.
In addition, a hypothetical case study is presented to give
the reader a sense of the actual costs and energy savings.
A listing of current manufacturers and technology users is
provided along with references for further reading.
Technology | Federal Sector
Potential | Application | Technology
Case Study | The Technology
in Perspective | Manufacturers
Information | Appendixes | Contacts | Disclaimer
addressed in this FTA uses a magnetic or electrostatic field
to alter the reaction between scale-forming ions in hard water.
Hard water contains high levels of calcium, magnesium, and
other divalent cations. When subjected to heating, the divalent
ions form insoluble compounds with anions such as carbonate.
These insoluble compounds have a much lower heat transfer
capability than heat transfer surfaces such as metal. They
are insulators. Thus additional fuel consumption would be
required to transfer an equivalent amount of energy.
The magnetic technology has been cited in the
literature and investigated since the turn of the 19th century, when lodestones or naturally occurring magnetic mineral
formations were used to decrease the formation of scale in
cooking and laundry applications. However, the availability
of high-power, rare-earth element magnets has advanced the
magnetic technology to the point where it is more reliable.
Similar advances in materials science, such as the availability
of ceramic electrodes and other durable dielectric materials,
have allowed the electrostatic technology to also become more
The general operating principle for the magnetic
technology is a result of the physics of interaction between
a magnetic field and a moving electric charge, in this case
in the form of an ion. When ions pass through the magnetic
field, a force is exerted on each ion. The forces on ions
of opposite charges are in opposite directions. The redirection
of the particles tends to increase the frequency with which
ions of opposite charge collide and combine to form a mineral
precipitate, or insoluble compound. Since this reaction takes
place in a low-temperature region of a heat exchange system,
the scale formed is non-adherent. At the prevailing temperature
conditions, this form is preferred over the adherent form,
which attaches to heat exchange surfaces.
The operating principles for the electrostatic
units are much different. Instead of causing the dissolved
ions to come together and form non-adherent scale, a surface
charge is imposed on the ions so that they repel instead of
attract each other. Thus the two ions (positive and negative,
or cations and anions, respectively) of a kind needed to form
scale are never able to come close enough together to initiate
the scale-forming reaction. The end result for a user is the
same with either technology; scale formation on heat exchange
surfaces is greatly reduced or eliminated.
These technologies can be used as a replacement
for most water-softening equipment. Specifically, chemical
softening (lime or lime-soda softening), ion exchange, and
reverse osmosis (RO), when used for the control of hardness,
can be replaced by the non-chemical water conditioning technology.
This would include applications both to cooling water treatment
and boiler water treatment, in once-through and recirculating
systems. Other applications mentioned by the manufacturers
include use on petroleum pipelines as a means of decreasing
fouling caused by wax build-up, and the ability to inhibit
biofouling and corrosion.
The magnetic technology is generally not applicable
in situations where the hard water contains "appreciable"
concentrations of iron. In this FTA, appreciable means a concentration
requiring iron treatment or removal prior to use, on the order
of parts per million or mg/L. The reason for this precaution
is that the action of the magnetic field on the hardness-causing
ions is very weak. Conversely, the action of the magnetic
field on the iron ions is very strong, which interferes with
the water conditioning action.
A search of the Thomas RegisterTM in conjunction with manufacturer contact
yielded eleven manufacturers of magnetic, electromagnetic
or electrostatic water conditioning equipment that fell within
the scope of this investigation. The defined scope includes
commercial or industrial-type magnetic, electromagnetic or
electrostatic devices marketed for scale control. Devices
intended for home use, as well as other non-chemical means
for scale control, such as reverse osmosis, are not within
the extended scope of this FTA.
Figure 1. Diagram of General Magnetic Device
Exact numbers of units deployed by these manufacturers
are virtually impossible to compile, as some of the manufacturers
had been selling the technology for up to 40 years. One manufacturer
claims as many as 1,000,000 units (estimated total of all
manufacturers represented here) are installed in the field.
Where not withheld by the manufacturer because of business
sensitivity reasons, customer lists included both Federal
and non-Federal installations. Those manufacturers who did
withhold the customer list indicated a willingness to disclose
customer contacts to legitimate prospective customers.
Literature provided by and discussions with
manufacturers described a typical installation for a boiler
water treatment scheme as including the device installed upstream
of the boiler. Manufacturers vary in their preference of whether
the device should be installed close to the water inlet or
close to the boiler. Both locations have been documented as
providing adequate performance. Generally, the preferred installation
location for use with cooling towers or heat exchangers is
upstream of the heat exchange location and upstream of the
cooling tower. Downstream of the cooling tower but upstream
of the heat source was also mentioned as a possible installation
location, primarily for the use with chillers or other cooling
The primary caveat on installation of
the magnetic technology is that high voltage (230V, 3-phase
or above) power lines interfere with operation by imposing
a second magnetic field on the water. (This is most noticeable
when these electric power sources are installed within three
feet of a magnetic device.) This second magnetic field most
likely will not be aligned with the magnetic field of the
device, thus introducing interference and reducing the effectiveness
of the treatment. Installations near high voltage power lines
are to be avoided if possible. Where avoidance is not possible,
the installation of shielded equipment is recommended to achieve
optimum operation. Some manufacturers also have limitations
on direction of installation--vertical or horizontal--because
of internal mechanical construction.
The primary energy savings result from a decrease
in energy consumption in heating or cooling applications.
This savings is associated with the prevention or removal
of scale build-up on a heat exchange surface where even a
thin film (1/32" or 0.8 mm) can increase energy consumption
by nearly 10%. Example savings resulting from the removal
of calcium-magnesium scales are shown in Table 1. A secondary
energy savings can be attributed to reducing the pump load,
or system pressure, required to move the water through a scale-free,
unrestricted piping system.
Table 1. Example Increases in Energy Consumption
as a Function of Scale Thickness
As was discussed above, magnetic and electric
fields interact with a resultant force generated in a direction
perpendicular to the plane formed by the magnetic and electric
field vectors. (See Figure 2 for an illustration.) This force
acts on the current carrying entity, the ion. Positively charged
particles will move in a direction in accord with the Right-hand
Rule, where the electric and magnetic fields are represented
by the fingers and the force by the thumb. Negatively charged
particles will move in the opposite direction. This force
is in addition to any mixing in the fluid due to turbulence.
Figure 2. Diagram Showing Positioning of
Fields and Force
The result of these forces on the ions is that,
in general, positive charged ions (calcium and magnesium,
primarily) and negative charged ions (carbonate and sulfate,
primarily) are directed toward each other with increased velocity.
The increased velocity should result in an increase in the
number of collisions between the particles, with the result
being formation of insoluble particulate matter. Once a precipitate
is formed, it serves as a foundation for further growth of
the scale crystal. The treatment efficiency increases with
increasing hardness since more ions are present in solution;
thus each ion will need to travel a shorter distance before
encountering an ion of opposite charge.
A similar reaction occurs at a heat exchange
surface but the force on the ions results from the heat input
to the water. Heat increases the motion of the water molecules,
which in turn increases the motion of the ions, which then
collide. In addition, scale exhibits an inverse solubility
relationship with temperature, meaning that the solubility
of the material decreases as temperature increases. Therefore,
at the hottest point in a heat exchanger, the heat exchange
surface, the scale is least soluble, and, furthermore due
to thermally induced currents, the ions are most likely to
collide nearest the surface. As above, the precipitate formed
acts as a foundation for further crystal growth.
When the scale-forming reaction takes place
within a heat exchanger, the mineral form of the most common
scale is called calcite. Calcite is an adherent mineral that
causes the build-up of scale on the heat exchange surface.
When the reaction between positively charged and negatively
charged ions occurs at low temperature, relative to a heat
exchange surface, the mineral form is usually aragonite. Aragonite
is much less adherent to heat exchange surfaces, and tends
to form smaller-grained or softer-scale deposits, as opposed
to the monolithic sheets of scale common on heat exchange
These smaller-grained or softer-scale deposits
are stable upon heating and can be carried throughout a heating
or cooling system while causing little or no apparent damage.
This transport property allows the mineral to be moved through
a system to a place where it is convenient to collect and
remove the solid precipitate. This may include removal with
the wastewater in a once-through system, with the blowdown
in a recirculating system, or from a device such as a filter,
water/solids separator, sump or other device specifically
introduced into the system to capture the precipitate.
Water savings are also possible in recirculating
systems through the reduction in blowdown necessary. Blowdown
is used to reduce or balance out the minerals and chemical
concentrations within the system. If the chemical consumption
for scale control is reduced, it may be possible to reduce
blowdown also. However, the management of corrosion inhibitor
and/or biocide build-up, and/or residual products or degradation
by-products, may become the controlling factor in determining
blowdown frequency and volume.
Aside from the energy savings, other potential
areas for savings exist. The first is elimination or significant
reduction in the need for scale and hardness control chemicals.
In a typical plant, this savings could be on the order of
thousands of dollars each year when the cost of chemicals,
labor and equipment is factored in. Second, periodic descaling
of the heat exchange equipment is virtually eliminated. Thus
process downtime, chemical usage, and labor requirements are
eliminated. A third potential savings is from reductions in
heat exchanger tube replacement due to failure. Failure of
tubes due to scale build-up, and the resultant temperature
rise across the heat exchange surface, will be eliminated
or greatly reduced in proportion to the reduction in scale
Devices are available in two installation variations
and three operational variations. First to be discussed are
the two installation variations: invasive and non-invasive.
Invasive devices are those which have part or all of the operating
equipment within the flow field. Therefore, these devices
require the removal of a section of the pipe for insertion
of the device. This, of course, necessitates an amount of
time for the pipe to be out of service. Non-invasive devices
are completely external to the pipe, and thus can be installed
while the pipe is in operation. Figure 3 illustrates the two
Figure 3. Illustration of Classes of Magnetic
Devices by Installation Location
The operational variations have been mentioned
above; illustrations of the latter two types are shown Figure
more correctly a permanent magnet
where the magnetic field is generated via electromagnets
where an electric field is imposed on the water flow,
which serves to attract or repel the ions and, in
addition, generates a magnetic field.
Figure 4. Illustration of Classes of Non-Permanent
Electrostatic units are always invasive. The
other two types can be either invasive or non-invasive. The
devices illustrated in Figure 3 are examples of permanent
Most of the devices are in-line--some invasive,
some non-invasive--as opposed to side-stream. The invasive
devices require a section of pipe to be removed and replaced
with the device. Most of the invasive devices are larger in
diameter than the section of pipe they replace. The increased
diameter is partially a function of the magnetic or electromagnetic
elements, and also a function of the cross sectional flow
area. The flow area through the devices is generally equivalent
to the flow area of the section of pipe removed.
The non-invasive in-line devices are designed
to be wrapped around the pipe. Thus downtime, or line out-of-service
time, is minimized or eliminated.
cost-effective savings achievable by this technology were
estimated as part of the technology assessment process of
the New Technology Demonstration Program (NTDP).
Technology Screening Process
New technologies were solicited for NTDP participation
through advertisements in the Commerce Business Daily and trade journals, and, primarily, through direct correspondence.
Responses were obtained from manufacturers, utilities, trade
associations, research institutes, Federal sites and other
interested parties. Based on these responses, the technologies
were evaluated in terms of potential Federal-sector energy
savings and procurement, installation, and maintenance costs.
They were also categorized as either just coming to market
("unproven" technologies) or as technologies for which field
data already exist ("proven" technologies).
The energy savings and market potentials of
each candidate technology were evaluated using a modified
version of the Facility Energy Decisions Screening (FEDS)
software too (Dirks and Wrench, 1993).
Non-chemical water treatment technologies were
judged life-cycle cost-effective (at one or more Federal sites)
in terms of installation cost, net present value, and energy
savings. In addition, significant environmental savings from
the use of many of these technologies are likely through reductions
in CO2, NOx, and SOx emissions.
Estimated Savings and Market
As part of the NTDP selection process, an initial
technology screening activity was performed to estimate the
potential market impact in the Federal sector. Two technologies
were run through the assessment methodology. The first technology
was assessed assuming the technology was applied to the treatment
of boiler make-up water. The second technology was assessed
assuming the technology was applied to both the treatment
of boiler make-up water and cooling tower water treatment.
The technology screenings used the economic basis required
by 10 CFR 436. The costs of the two technologies were different
based on information provided by the manufacturers, thus leading
to different results.
The technologies were ranked on a total of
ten criteria. Three of these were financial, including net
present value (NPV), installed cost, and present value of
savings. One criterion was energy-related, annual site energy
savings. The remaining criteria were environmental and dealt
with reductions in air emissions due to fuel or energy savings
and included SO2, NOx, CO, CO2,
particulate matter and hydrocarbon emissions.
The ranking results from the screening process
for this technology are shown in Table 2. These values represent
the maximum benefit achieved by implementation of the technology
in every Federal application where it is considered life-cycle
cost-effective. The actual benefit will be lower because full
market penetration is unlikely to ever be achieved.
Table 2. Screening Criteria Results
| Net Present Value ($)
Installed Cost ($)
Present Value of Savings ($)
Annual Site Energy Savings (Mbtu)
SO2 Emissions Reduction (lb/yr)
NOx Emissions Reduction (lb/yr)
CO Emissions Reduction (lb/yr)
CO2 Emissions Reduction (lb/yr)
Particulate Emissions Reduction (lb/yr)
Hydrocarbon Emissions Reduction (lb/yr)
|Note: First Screen:
Boiler make-up water treatment.
Second Screen: Cooling tower water treatment and
boiler make-up water treatment.
The primary question to be answered is "Does
the technology work as advertised?" The history of the technologies,
as illustrated through primarily qualitative--but some quantitative--assessment
in many case studies, has shown that when properly installed,
a decrease in or elimination of scale formation will be found.
While the evidence supporting the technologies may be thought
of as mainly anecdotal, the fact remains that upon visual
inspection after installation of these devices the formation
of new scale deposits has been inhibited. In addition, in
most cases, scale deposits present within the system at the
time of installation have been removed.
The key here is properly installed.
By this it is meant that a manufacturer or their qualified
representative is responsible for equipment integration. Unlike
many other technologies where much of the knowledge has been
reduced to a quantitative model, the non-chemical water treatment
industry still relies largely on experience as the means of
providing quality installation, service and, consequently,
Of particular interest to the manufacturer
would be physical parameters such as water flow rate, and
water quality parameters such as hardness, alkalinity, and
iron concentration. These parameters will help determine the
optimum size and the extent of treatment.
The manufacturer may also want to know whether
the installation is for use in conjunction with a boiler or
a cooling tower, and for once-through or recirculating water
systems. These parameters will help determine the optimum
location within the system.
Other factors of interest may include whether
the cooling or heating system is sensitive to particulate
matter, and if so what particle sizes. The device works by
initiating the precipitation of scale, thus particulate matter
will be present in the treated water. If the system is sensitive
to particulate matter there may be a need for a solid separation
device such as a filter, a settling basin, a cyclone, or a
sump to collect solids and to allow for their easy removal
from the system.
addresses the technical aspects of applying the technology.
The range of applications and climates in which the technology
can be applied are addressed. The advantages, limitations,
and benefits in each application are enumerated. Design and
integration considerations for the technology are discussed,
including equipment and installation costs, installation details,
maintenance impacts, and relevant codes and standards. Utility
incentives and support are also discussed.
As mentioned previously, the technology can
be applied wherever hard water is found to cause scale. Since
the technology is a physical process, as opposed to chemical
water softening, it is expected to perform best in locations
with harder water. In general, only a few locations do not
require or would not benefit from some type of hardness control.
Hard water is one in which the hardness is greater than 60 mg/L
(or ppm) as calcium carbonate. This corresponds to approximately
3.5 grains of hardness per U.S. gallon. The Pacific Northwest
states, the North Atlantic coastal states, and the Southeast
states, excluding Florida, are locations where naturally occurring
soft water is most likely to be found. The balance of the
United States could benefit from some type of water treatment
to control scale formation, using either one of the traditional
technologies such as lime softening or ion exchange, or the
non-chemical technology discussed in this FTA.
Where to Apply
Non-chemical scale control technologies can
be used for either boiler scale control or cooling tower scale
control. Boiler scale control applications are the majority
of the installations, but the control of silica scale in cooling
water applications is also possible. Experience has been cited
with both retrofit installations and in new installations
(see References for a brief listing of applicable reports
Non-chemical scale control technologies are
use of chemicals for water treatment is to be minimized
or eliminated. Lime, salt and acid for cleaning can
be reduced or eliminated.
requirements do not allow installation of lime softening
equipment or ion exchange equipment. The non-chemical
technologies are generally very space efficient.
matter in the water can be tolerated by the process;
otherwise solids separation is required.
system shutdowns are required for descaling even with
a diligent chemical scale control program.
locations where delivery of chemicals and labor cost
makes conventional water softening or scale control
methods cost prohibitive.
What to Avoid
There are a few precautions to be noted before
selecting the technology:
is littered with disreputable manufacturers or vendors,
the actions of whom have given the technology an undesirable
history in the eyes of many. Work with a reputable
manufacturer (such as those included herein) through
their engineering department or their designated installer.
These people have much more experience with the technology
than the typical water treatment engineering firm.
of process water requirements since these requirements
may dictate the need to install solids separation
equipment or iron removal equipment in order to maximize
the performance of the technology.
near high voltage electrical equipment or strong magnetic
fields is to be avoided since these fields will interfere
with the performance of the technology. (Near is relative
to the voltage; for 208/220/240V it means within 36
inches; for higher voltages it is proportionally more
distant.) Also, check the pipeline for its use as
an electrical ground. Stray electrical current in
the pipe will have the same effect as installation
near a strong electrical or magnetic field.
Installation issues with these devices are
few. The first issue is whether a permanent magnet or one
of the electronic devices is chosen. The latter needs a suitable
supply of electricity.
The second issue is device capacity, which
will dictate space requirements and pipe size. The pipe size
generally determines the fittings. Smaller devices, up to
approximately 2" pipe size, are available with solder or pipe
thread fittings. Larger devices may have flange fittings that
would necessitate the installation of matching flanges in
the current pipe arrangement.
The third issue is the potential for downtime,
which needs to be coordinated with other facility activities.
However, this should not be a major impediment since downtime
for cleaning and maintenance of cooling towers, or boiler
inspection is part of the regularly scheduled activities for
A fourth issue would arise with the corrosion
control chemistry, which will likely need some adjustment
under a non-chemical scale control technology. In many cases
the layer of scale on heat transfer surfaces is beneficial
from a corrosion control standpoint. With this layer not present
when using a non-chemical technology, the concentration of
corrosion control chemicals may need adjustment in order to
provide the proper protection. On the reverse side, many users
are claiming the presence of a fine powdery film on the surfaces
the treated water contacts. This powder has been attributed
to serve as a corrosion inhibitor.
The most significant issue may be whether a
solids separation device is needed to remove the particulates
formed. Filters, hydrocyclones, and settling basins are all
compatible with the technology. The choice among these or
other solids separation technologies should be made in conjunction
with the manufacturer who will have the best idea of particle
size distribution, and thus the relative efficiencies of the
There is a significant, positive impact on
maintenance. Field applications have shown the technology
to be capable of controlling scale for extended periods of
time, months or years, eliminating the periodic cleaning or
descaling of process equipment that is typical of conventional,
chemical-based scale control technologies. The resources--time,
chemicals, and equipment--previously devoted to periodic scale
removal from heat exchange surfaces will be made available
for other tasks. Note, however, the need for periodic inspection
of the heat exchange surfaces is not reduced or eliminated.
The electrostatic devices also require periodic
inspection of the electrodes. This scheduled maintenance activity
can be performed in conjunction with the heat exchange surface
inspection and requires less than a person-day to disassemble
and inspect the system.
All of the manufacturers offer some type of
warranty on their respective device. The range is from 90 days
to as much as 10 years. Another perspective is the potential
impact upon warranties for installed equipment. No information
was uncovered as part of this effort to indicate any instance
where a boiler or cooling tower equipment manufacturer voided
a warranty for equipment. However, no specific effort was
made to contact manufacturers of boilers and cooling tower
equipment to assess specific warranty conditions or policies.
Codes and Standards
Only one code or standard specific to the non-chemical
technologies was identified in the course of preparing this
FTA: API 960, Evaluation of the Principles of Magnetic Water
Treatment, 09/1985, 89 pages. Of course, all applicable
plumbing, piping, mechanical, and/or electrical codes and
standards would still apply.
Cost information was requested from each manufacturer
for three different-size units, based on flow rate: 1 gpm
(gallons per minute), 100 gpm and 1,000 gpm. As is typical
of process equipment, cost per unit of treatment decreases
with increasing capacity. To treat 1 gpm, a typical cost was
on the order of $100, or about $100 per gpm. To treat 1,000
gpm a typical cost was on the order of $10,000, or about $10
In general, the electronic units were more
costly than the magnetic units for an equivalent flow rate.
Costs also ranged considerably with unit size, with the 1-gpm
units ranging in cost up to $500. For the 1,000-gpm units
the range of costs was considerably greater, from $900 to
Installation costs also varied widely, in conjunction
with equipment size. The lower flow rate units will mate with
3/4" to 1" pipe sizes with soldered, flanged or threaded (NPT)
fittings. Installation time estimates were on the order of
one hour, with additional parts costing less than $10. The
larger-size units (1,000 gpm) were typically designed to mate
with a 12" to 18" pipe using a flange fitting. Estimated installation
time ranged from one to four person-days, requiring less than
$1,000 in additional materials.
Weight was an important characteristic in the
installation estimate because the permanent magnet units may
exceed 1,000 pounds. There is a trade-off between installing
a heavier permanent magnet unit requiring no outside power
versus a lighter electronic unit for which an electrical connection
needs to be made, and possibly electrical lines run to the
point of installation. The net effect is expected to be neutral
with regard to installation time estimates.
Since these units are typically delivered in
the sizes quoted off-the-shelf, there is no design cost by
the manufacturer. Facilities engineering and design for calculations
and updating plant drawings should amount to less than two
person-days for the large units, and less than an hour for
the small units.
Utility Incentives and Support
Although no specific incentive programs were
identified, the Department of Energy and the Advanced Research
Projects Agency have funded research in this area. Some utility
or trade associations have supported the electronic technologies
with funds and exposure. For example, the American Water Works
Association sponsored a conference to discuss the non-traditional
treatment technologies. In addition, as California municipalities
face water shortages, they have turned to a number of measures
to lower water consumption and increase water quality. Many
have prohibited the use of water softeners and may offer assistance
infunding conversion to low/no salt water conditioning technologies.
There are additional considerations to be taken
into account. Primary among these is the reduction in chemical
use at the facility for water softening. The chemical use
reduction may lead to reduced safety, training and reporting
Electricity consumption will also be reduced.
The actual reduction is highly dependent upon the technology
employed. Permanent magnets use no electricity, so both the
on-site electricity used for chemical treatment as well as
the off-site energy required to produce and transport the
chemicals will be eliminated. For the electronic units, on-site
energy requirements may vary from as little as 10% of the
chemical-based treatment system energy consumption--typical,
to 10 times the energy consumed by the chemical-based treatment
Energy consumption reductions will lead directly
to reductions in air combustion emissions. There will also
be additional indirect reductions due to decreased transportation
of fuels and decreased fuel processing. The latter will also
lead to reductions in water use, water pollution, and solid
wastes from mining and processing operations.
in this section was compiled primarily from case studies,
along with selected contact with users and third party researchers.
As mentioned previously, the use of magnetic or electric fields
to treat water had its origins near the turn of the 19th century. Commercialization of the technology began after World
War II, with the largest advances coming in the last 20 years
with the development of rare earth magnets and inexpensive
There are records of installation of the technology
in the United States from about 1950. Manufacturers claim
to have installations operating satisfactorily for as long
as 30 years. No good statistics were available on the total
number of installations over this period. However, using the
estimates of one manufacturer as a basis, there could be upwards
of 1,000,000 units installed in the United States in commercial
or industrial facilities, inclusive of all units installed
by all manufacturers.
As has been alluded to above, user experience
has been positive. Two experiences have been common. First,
users have noted a dramatic reduction in scale formation to
the point where the need for chemical scale control is eliminated.
Second, the prior build-up of scale on heat exchange surfaces
has been removed over time. This last process has been noted
as taking from 30 days to over a year, depending upon the
thickness and composition of the scale.
This is not to say there have not been less
than successful installations or applications. The non-chemical
technologies may not be universally applicable for scale control,
just as any technology may not be a universally applicable
solution to the problem it was designed to solve.
The magnetic technologies are not as effective
when silica is present in the system. Nor do they work as
efficiently when iron is present, as was mentioned above,
or when other magnetic minerals are present. The history of
the technology is also littered with cases where the magnet
field was applied incorrectly or did not have sufficient strength
to affect the reaction. This latter was especially true early
in the life cycle of the technology when ferrous-based magnets
were the norm. High levels of particulate matter will also
negatively influence the efficiency of the technology by reducing
the collision frequency of the desirable reactions.
Energy savings result from both reductions
in pumping energy input to the system and reduction in fuel
consumption. The first aspect has not been well quantified
by the users or in any of the case studies. It is thought
of as a secondary benefit.
Fuel consumption has been lowered in every
situation. The exact savings are a result of a number of factors:
the chemical scale control program may have been relative
to the input water hardness
the heat exchange system was taken down for maintenance
On systems that were descaled frequently or
had low scale formation, due to low hardness and/or an effective
chemical scale control program, the savings in fuel consumption
was lower, often from a few percent to as much as 15%. The
lower savings were at an installation using ion exchange softening
of moderately hard water (less than 150 mg/L as calcium carbonate
hardness). On systems where descaling was infrequent or absent
altogether, or where the chemical scale control program was
not as effective in controlling scale formation, fuel consumption
savings ranged up to 30%. This was found to be the case in
an installation using very hard water (hardness in excess
of 300 mg/L as calcium carbonate), andd a chemical scale control
program, with heat exchanger tubes closing due to scale formation
after less than one year. In each case the fuel consumption
savings was proportional to the thickness of the scale layer
One important note was that fuel consumption
savings often trailed installation of the technology by a
significant period due to the fact that the savings is driven
by the amount of scale on the heat exchange surface. The accumulated
scale will erode over time, resulting in fuel consumption
reductions. For this reason, many of the manufacturers recommend
installing the technology only after the system has been descaled,
thus savings in fuel consumption would be immediate.
As mentioned above, maintenance requirements
typically are reduced upon implementation of the non-chemical
technology. First, periodic maintenance of the water-softening
equipment and chemicals is eliminated. Second, the periodic
heat exchanger inspection and cleaning cycle is reduced to
an inspection cycle. The handling and storage requirements
for the chemicals--lime, soda ash, salt and acid--have been
eliminated, as has training for their use, storage and handling.
The reduction in these periodic activities frees up the previously
time allocated for application to other activities.
There are maintenance activities associated
with this technology. For the electromagnetic and electrostatic
units, a daily check that the power is on is necessary (a
"power on" indicator light is included with most, if not all,
units). The electrostatic units need to have the electrodes
checked periodically, semi-annually, and the electrodes replaced
when noticeably worn or damaged, perhaps every five years.
The reader should speak to the manufacturer for details which
When solids or particulates accumulate in the
system, they will need to be removed. Automatic blowdown of
the system should control the daily accumulation. If the system
is not cleaned prior to installation of the non-chemical technology,
the scale in the system will detach and its removal will be
necessary. Filters, sumps and hydrocyclones are all effective
means of capturing the solids, but each will require periodic
There are areas where the technology mitigates
environmental impacts. The first is air quality due to emissions
reduction associated with decreases in fuel consumption. The
second is a corresponding decrease in solid wastes, ash and
other fuel combustion residues to be disposed. Of course,
this will only be applicable in the situation in which an
end user combusts fuels on-site for the production of power.
A third area is the reduction in release, or potential for
release, of water treatment chemicals stored at a facility.
Since chemical consumption will decrease, emissions from storage
will also decrease. The wastes associated with disposal and
management of used chemical containers will also be reduced.
For the case
study, a hypothetical facility is used and the application
of a permanent magnet device is described. The conditions
are based on information gathered during the user interviews
and reading of published and unpublished case studies. The
purpose is to illustrate the types of data required to prepare
a site-specific cost analysis, not to illustrate what any
particular user might experience in the way of cost savings.
The facility currently uses extremely hard
water (hardness of 350 mg/L as calcium carbonate) and employs
lime softening. The process water is used in a recirculating
boiler water system with flow of 1,000 gpm or 1.4 MGD (million
gallons per day). Makeup and blowdown were estimated at 10%
of the flow, or 140,000 gallons per day. The water-softening
process removes a significant fraction of the hardness, but
not all, leading to semiannual inspections and annual cleaning
of the heat exchanger. This frequency is thought to be fairly
Cost for the lime used in the process is estimated
at $10/ton delivered. Cost for natural gas is $5.80/1000 ft3.
Acetic acid, used for cleaning, costs $2 per gallon.
Existing Technology Description
The current system is a conventional lime softening
plant consisting of lime storage facilities, a slaker where
the powered lime is mixed with water, a mixing basin for adding
controlled amounts of the lime solution to the water, and
a settling basin where the precipitated solids are removed.
Downstream of the water treatment facilities is a conventional
shell-and-tube heat exchanger used to heat the water for both
building heat and process water.
Lime consumption for softening is 48 tons/year.
In this case, alkalinity is sufficient so as to not require
the addition of soda ash during the softening process. Natural
gas consumption for process water heating is 400,000 MBtu/year.
Electricity consumption for the softening process was estimated
at 3,100 kWh per year. Acetic acid is used during cleaning,
approximately 100 gallons per cleaning. Production losses
due to system downtime are not being included in this analysis.
(If the system had instead used ion exchange
softening, the applicable chemical use information would have
been the regenerant, typically salt but possibly acid, and
the consumption of ion exchange resin. This last item is calculated
as the mass replaced divided by the total volume of water
Data on lime consumption can typically be found
in purchasing records, or also in a water treatment system
operator's log. The latter would be more accurate since it
would more closely reflect lime used for water softening,
whereas the former would list only lime purchases including
those for water softening, pH adjustment and other uses.
Natural gas consumption, or other fuel consumption
data, can be taken from accounting records, if the only use
of natural gas is for process water, or from operation data,
(e.g., firing rate data), or calculated from an energy balance
for a portion of the production system. The firing rate data
or other operation data would be the most accurate but might
not always be available.
Electricity consumption information can be
calculated from nameplate capacity of the mixing and pumping
equipment involved. For this report, it was derived from information
compiled by the Electric Power Research Institute. In some
cases there may be energy or monitoring data available for
the process that would be available as part of the water treatment
system operator's records.
New Technology Equipment
A magnetic scale control device will be investigated
as an alternative to chemical scale control. The first step
was consultation with the manufacturer, including submitting
water analysis data and a schematic of the current system
showing the proposed location of the equipment to facilitate
manufacturer selection and equipment sizing. (A magnetic device
was chosen because the preferred installation location was
remote, with electrical power not readily available.)
For the proposed location and required flow
rate, a unit was identified that would fit the current piping
configuration without a need for adapters. The unit cost is
$10,000 including shipping. The estimate by the in-house facilities
engineering staff calls for three days to install the system,
one-half day each for set-up and clean-up, one day to remove
a section of pipe to make space for the device (including
installing flanges), and one day for installation and leak
testing. Three people are required, as well as a device capable
of lifting 1,000 pounds in order to position the device and
facilitate removal of the old section of pipe.
One of the key elements to sizing these devices
is the water velocity through the device. Manufacturers recommend,
typically, at least a 7 feet per second water velocity. If
the water velocity through a section of pipe is too low, it
will be necessary to use adapters to decrease the size of
the pipe through the device, thus increasing the velocity.
Water velocity in feet per second can be calculated as follows,
where Diameter is in feet:
Savings are expected to result from discontinuance
of chemical consumption and decreased energy consumption (10%
of process energy and all of the water treatment energy).
Inspection will still occur.
Energy savings can result from two areas. First
is the reduction in fuel used in generating heat. Methods
for calculating the fuel consumption were discussed above
in the technology descriptions. The fuel consumption savings
is simply the net difference, in this case estimated equal
to 10% of the baseline fuel consumption. (This estimated savings
was used to illustrate a case where there was a fairly uniform
1/16" thick layer of scale across a heat exchanger surface.
Of course, it is realized that the scale layer, and therefore
energy consumption, builds over time and is not an instantaneous
effect.) This savings is also equal to the loss in heat transfer
efficiency due to scale formation on the heat exchange surface.
Second is the energy savings resulting from
decreased pressure drop within the heat exchanger. This is
not quantified here, but could be quantified if the pressure
drop through the current system was known, along with the
energy characteristics of the pump so that reductions in pressure
could be related to energy consumption.
Cost savings also result from reductions in
chemical use. Chemical softening will be reduced, and likely
eliminated, by the use of non-chemical treatment technologies.
There will also be a corresponding energy decrease from the
shutdown of chemical mixing equipment and water treatment
equipment used in the softening process. The estimated chemical
savings here was 480 tons per year and the corresponding electricity
savings was 31,000 kWh per year.
Table 3 illustrates typical consumption data
for the baseline and alternative and the potential annual
costs savings. Not shown are water consumption and water discharge,
which do not change between the alternatives. Capital cost
for the alternative treatment system, estimated at $10,000
at the beginning of the 15-year analysis period, is not shown
either. Fifteen years was chosen because it was typical of
the life of field units.
Table 3. Annual Costs and Savings
The full results of the BLCC computations are
shown in Appendix B. A discussion of the BLCC software is
given in Appendix A. The BLCC Comparative Economic Analysis
is shown in Figure 5. Installation cost for the magnetic treatment
device is estimated at $10,360, calculated as $10,000 for
the device and $360 for design and installation labor. Operating
costs for the technology are estimated at $2,088,000 per year
versus costs of $2,320,635 per year for the conventional lime-softening
technology, both exclusive of water consumption and discharge.
Life-cycle costs for each of the technologies as calculated
by the BLCC software are $27,524,500 for the magnetic technology
versus $30,283,500 for the conventional technology. (This
includes the cost of water and wastewater disposal of $2,605,292.)
This represents a life-cycle cost savings of $2,759,000. The
Simple Payback from BLCC is less than one year, and the Adjusted
Internal Rate of Return is 50.66%.
Figure 5. Comparative BLCC Analysis
of non-chemical water treatment technologies is promising.
As public awareness of the environmental effects of chemicals
increases there will be an increasing demand to deploy alternative,
more environmentally beneficial technologies. As a means of
reducing energy consumption and stretching the available personnel
resources in the days of ever-shrinking budgets, non-chemical
technologies make sense as both cost effective and having
The Technology's Development
Magnetic and electrical effects on water were
first noticed prior to the turn of the 20th century.
Considerable research is being conducted on magnetohydrodynamics
by the Japanese as a means of propulsion, and similar research
has been conducted in the past in the United States and other
industrialized countries. This research has been facilitated
by the advent of rare earth magnets, solid state electronics,
and advanced ceramic or polymeric materials after World War
II. Only after these advances has non-chemical water treatment
shown promise and come into more widespread use.
Of the manufacturers listed in this FTA most
have come into existence since the advent of the environmental
movement in the United States in the early 1970s. This can
be attributed both to the advent of cost-effective components
(e.g., magnets, electronics) and to the public desire for
more "green" or environmentally friendly alternatives to chemical
Relation to Other Technologies
The use of the non-chemical technologies does
not prohibit the use of any other technology or equipment.
As was mentioned previously, the change from chemical to non-chemical
scale control may warrant investigation of other means of
corrosion or biofouling control, as these three chemical scale
treatment or control strategies or applications are often
balanced amongst each other.
An increase in cycles of concentration was
also noted by one user as another water saving measure that
was employed. The ability to increase the cycles of concentration
was attributed to the stability of scale-forming ions or scale
particles in suspension. Water consumption was halved in this
There is no basis to assume that the technologies
are going to disappear anytime soon. Each has a historical
basis of successful installations. Advances in materials science
should only serve to improve each of the technologies. More
powerful magnets will allow the magnetic devices to become
smaller and/or more efficacious. More durable electrodes and
dielectric compounds will improve the life of the electrostatic
Probably the most significant trend is the
move away from chemical treatment technologies. This trend
has begun at the consumer level, is becoming apparent at the
corporate level, and will continue to grow. Increased availability
of information on the technologies, the environment, and human
health will only serve to feed this trend.
The following is a
listing of manufacturers of these technologies compiled
from the Thomas Register and those who have contacted
FEMP directly. It has been limited to U.S. manufacturers;
foreign manufacturers or U.S. affiliates of foreign
manufacturers were not included. No effort was made
to locate and include manufacturers not listed in the
Thomas Register. This listing does not purport to be
complete, to indicate the right to practice the technology,
or to reflect future market conditions.
|Advanced Environmental Products
9450 Schulman #113
Dallas, TX 75243
6244 Frankford Avenue
Baltimore, MD 21206
|Aqua Magnetics International, Inc.
915-B Harbor Lake Drive
Safety Harbor, FL 34695
30555 Southfield Road #420
Southfield, MI 48076
4855-T Brookside Ct. Suite A
Norfolk, VA 23502
|Electrostatic Technologies Inc.
2223 Guinotte Avenue
Kansas City, MO 64120
125 Bayliss Road Suite 190
Mellville, NY 11747-3800
306 Railroad Street
P.O. Box 85
Union City, MI 49094
1615 W. Abram Street #110
Arlington, TX 76013
Superior Manufacturing Division
2015 S. Calhoun Street
P.O. Box 13543
Fort Wayne, IN 46868
|Progressive Equipment Corp.
419 East 9th Street
Erie, PA 16503
|Quantum Magnetic Systems Inc.
5224 Blanche Ave.
Cleveland, OH 44127
|Zeta Hydrometals Corporation
4565 S. Palo Verde Road, Suite 213
Tucson, AZ 85714
Included here are but a few of the installations
provided by the manufacturers. For a full listing the reader
is advised to contact a manufacturer directly. Some manufacturers
expressed concern about printing customer names in a public
list such as this Federal Technology Alert but indicated they
could provide such customer references to interested potential
buyers. Most manufacturers specify having hundreds to almost
10,000 installations. Not all of these sites were contacted
during the course of preparing this FTA.
Aeronautics and Space Administration, multiple locations
United States Coast Guard, multiple locations
Air Force, Luke AFB, Phoenix, AZ
Army Corps of Engineers, Sacramento District, Sacramento,
Environmental Protection Agency, Andrew W. Breidenbach
Environmental Research Center, Cincinnati, OH (Rich
Koch and Bob Banner, Cleveland Telecommunications
Postal Service, multiple locations
Cincinnati, OH (Hank Majeushi, 513/533-9600)
Steel, multiple locations Chrysler, multiple locations
Company, multiple locations
Electric, multiple facilities
Motors, multiple facilities
Los Angeles, CA
the Future, Ahwatukee, AZ (Arnold Roy, The Frank Lloyd
Wright Foundation, 602/948-6400)
Center, Chicago, IL
Coatings Inc. (Bob Bernadin and Ron Byers, 219/456-3596)
Steel, over 100 installations
Playing Card Company, Cincinnati, OH (Tom Berens,
No trade associations
exist that are specific to the non-chemical water treatment
technology manufacturers. The following associations
are general water quality associations.
American Water Works Association
6666 West Quincy Ave
Denver, CO 80235
Cooling Tower Institute
P.O. Box 73383
Houston, TX 77273
Water Quality Association
4151 Naperville Road
Lisle, IL 60532
|Robert A. Marth
340 Central Avenue
Sunnyvale, CA 94086
|T. Craig Molden
Water Service Technology/NWI
P.O. Box 545 Michigan City, IN 46361
User and Third Party Field
The following references represent only a small
sample of the published work on these technologies. The references
here are intended to give the reader an indication of the
history of scientific research on the topic as well as the
sponsoring agencies and interested audiences.
Alleman, J. 1985. Quantitative Assessment
of the Effectiveness of Permanent Magnet Water Conditioning
Devices. Purdue University. Sponsored by and protocol
by Water Quality Association.
American Petroleum Institute. 1985. Evaluation
of the Principles of Magnetic Water Treatment, Publication
Baker, J.S., and S.J. Judd. 1996. "Magnetic
Amelioration of Scale Formation." Water Research, 30(2):247-260.
Benson, R.F., B.B. Martin, and D.F. Martin.
1994. "Management of Scale Deposits by Diamagnetism. A Working
Hypothesis." Journal Environmental Science and Health,
Busch, K. W., M. A. Busch, D. H. Parker, R.
E. Darling, and J. L. McAtee, Jr. 1986. "Studies of a Water
Treatment Device That Uses Magnetic Fields," In Proceedings
Corrosion/85, Boston MA.
Dirks, J.A., and L.E. Wrench. 1993. "Facility
Energy Decision Screening (FEDS) Software System." PNL-SA-22780.
In Proceedings of the Energy and Environmental Congress.
Minneapolis, Minnesota, August 4-5, 1993.
Fryer, L. 1995. "Magnetic Water Treatment A
Coming Attraction?" E-Source, TU-95-7
Gruber and Carda. 1981. Performance Analysis
of Permanent Magnet Type Water Treatment Devices. South
Dakota School of Mines and Technology. Sponsored by and protocol
by Water Quality Association.
Hibben, S.G. 1973. Magnetic Treatment of
Water. Advanced Research Projects Agency of the Department
Marth, R.A. 1997. A Scientific Definition
of the Magnetic Treatment of Water: Its Subsequent Use in
Preventing Scale Formation and Removing Scale. Research
Conducted for Descal-A-Matic Corporation.
Parsons, S.A., Bao-Lung Wang, S.J. Judd, and
T. Stephenson. 1997. "Magnetic Treatment of Calcium Carbonate
Scale -- Effect of pH Control." Water Research, 31(2):
Quinn, C.J., T.C. Molden, and C.W. Sanderson.
1996. "Nonchemical Approach to Hard Water Scale, Corrosion
and White Rust Control." In Proceedings Iron and Steel
Engineer, Chicago IL, September 30, 1996.
Reimers, R.S., P. S. DeKernion, and D. B. Leftwich.
1979. "Sonics and Electrostatics - An Innovative Approach
to Water and Waste Treatment." In Proceedings Water Reuse
Symposium, Volume 2. American Water Works Research Association
Research Evaluation, Denver, CO.
Rubin, A.J. 1973. To Determine if Magnetic
Water Treatment is Effective in Preventing Scale. The
Ohio State University, Columbus, OH.
Schmutzer, M. A., and G. W. Hull. 1969. Examination
to Determine the Physical or Chemical Differences Between
Untreated and Magnetically Treated Water. United States
Testing Center, Inc. Hoboken, NJ.
Simpson. L. G. 1980. "Control Scale and Save
Energy." The Coast Guard Engineer's Digest, Volume
20, Number 205, pp. 32-35.
Design and Installation
Many of the manufacturers have guides for internal
use or use by their recommended installer or sales agent.
Contained in these guides are listings of customers, design
and installation notes, warranty information, and answers
to many user questions. Most or all of this information may
not be available to customers. However, the manufactures do
make available sales brochures and summaries of specific applications
or case studies. Also included with the units will be owner's
manuals and other end user installation and maintenance documentation.
Federal Life-Cycle Costing Procedures and the BLCC Software
Appendix B: Life-Cycle Cost Analysis Summary
New Technology Demonstration Program
Federal Energy Management Program
U.S. Department of Energy
1000 Independence Avenue, SW, EE-92
Washington, DC 20585
Fax: (202) 586-3000
|Steven A. Parker
Pacific Northwest National Laboratory
P.O. Box 999, MSIN: K5-08
Richland, Washington 99352
Fax: (509) 375-3614
Battelle Columbus Operations
505 King Avenue
Columbus, Ohio 43201
Produced for the U.S. Department of Energy by Battelle Columbus
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recommendation, or favoring by the United States Government
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