Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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WATER TREATMENT SYSTEM
RELATED APPLICATIONS
This application claims priority of United States Provisional Application
Serial Number 60/813,267, filed June 13, 2006.
FIELD OF THE INVENTION
The invention pertains to treatment of water to remove metals and other
undesirable substances from well and grounclwater so as to render the water
potable.
BACKGROUND OF THE INVENTION
Water for domestic, industrial and farm use frequently is contaminated
with minerals, organic substances, and bacteria that render the water
unpotable
and even dangerous to health. Among these contaminants is ferrous iron, which
forms a colloidal mass with water and fouls plumbing. Manganese and arsenic,
both toxic metals, are frequently found in water. Another is hydrogen sulfide,
which imparts a rotten egg srnell to the water. Organic substances may include
pesticide residues, drug metabolites and other contaminants that are released
into
the groundwater. Harmful bacteria such as Salmonella sp., E. coli, Shigella
sp.
and Clostridia sp. have been implicated in outbreaks of illness with
significant
mortality.
These contaminants generally have one thing in common: they are
inactivated, killed or transformed to innocuous substances when oxidized.
Municipalities have long treated their water supplies with oxidants such as
chlorine to control contamination. Chlorine is not totally harmless. For those
small municipalities or individual farms or homes, it is impractical to use
chlorine to treat water.
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A widely used treatment system employs the chemical oxidant potassium
permanganate to oxidize contaminants. Sasically, running water is passed
through a bed of permangariate to convert thefouling ferrous iron to the
soluble
ferric iron and the odorous hydrogen sulfide to non-odorous sulfate. Other
contaminants are likewise oxidized to harmless chemicals and bacteria are
killed.
This system, though effective, is difficult and expensive to maintain and
requires
periodic backflushing and replacement of the permanganate. Permanganate
being a toxic and reactive chemical, service of the system can be hazardous.
Oxygen may be used. Oxygen content of water may be raised by several
means: bubbling with air; spraying the water into the air; applying pressure
to
increase the dissolved oxygen, or by the electrolysis of water.
United States Patent No. 6,171,469 described raising the oxygen content
of water by passing the water through a set of electrolysis cells. In order to
raise
the oxygen content to the desired 13-17 ppm, it is necessary to recirculate
the
water past the cells 15 to 55 times.
None of these methods except the permanganate system deliver treated
water on demand, but require the construction of a retention tank and thus are
not convenient for home or farm use.
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SUMMARY OF THE INVENTION
The present invention provides one or a plurality of emitters contained in
one or a plurality of electrolysis chambers through which water flows. When
activated, the emitters cause the evolution of microbubbles of oxygen. The
emitters are connected to a power source controlled by a controller containing
a
flow switch. When the flow switch senses water demand, that is, when a spigot
is opened, the controller causes voltage to be applied to the electrolysis
cells.
The electrolysis cell or cells comprise electrodes separated from each other
by a
critical distance as more fuily described in co-pending patent application
serial
number 10/732,326 (the "`326" application)', the teachings of which are
incorporated by reference. Briefly, the anode and cathode are separated by
0.005
to 0.140 inches. The most preferred critical distance is 0.065 inches. Any
cathode or electrode known in the art may be used. Any number of emitters may
be arranged in the electrolysis chamber; the following examples show a typical
array of three rectangular emitters, but it is understood that the invention
is not
limited to three, but may comprise one to several or hundreds of emitters,
depending on the volume of running water to be treated. Likewise, it may be
convenient to pass the water through a plurality of chambers, arranged in
series
or in parallel, in order to make a more compact unit or to treat large
quantities of
flowing water.
In the preferred embodiment, the cathode and electrode are formed of the
same material and the controller causes the polarity to be reversed at a set
signal.
Many cathodes and anodes are commercially available. United States Patent
Number 5,982,609 discloses cathodes comprising a metal or metallic oxide of at
least one metal selected from the group consisting of ruthenium, iridium,
nickel,
iron, rhodium, rhenium, cobalt, tungsten, manganese, tantalum, molybdenum,
lead, titanium, platinum, palladium and osmium or oxides thereof. Anodes are
preferably formed from the same metallic oxides or metals as cathodes.
Electrodes may also be formed from alloys of the abbve metals or metals and
oxides co-deposited on a substrate. The cathode and anodes may be formed on
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any convenient support in any desired shape or size. The most preferred
electrode is titanium coated with iridium oxide.
Polarity of the electrodes is reversed in order to clean the electrodes of
deposited minerals. The time of reversal may be set for any convenient
interval
or be activated by any convenient means. The means for reversal include:
reversal each time the well pump turns on; when the water flow is initiated;
at
timed intervals from 45 seconds to 24 hours or more; or manually. When the
water flow is intermittent, it is convenient to program the controller to
change
polarity each time the flow switch detects a flow of water. The preferred
embodiment is self-cleaning; mineral residue tends to build up on the cathode
when current is flowing. When the current is reversed, the anode and the
cathode change polarity. The mineral buildup on the former cathode is repelled
and starts to form on the new cathode. This reversal of polarity limits the
amount
of buildup and the emitter is essentially self-cleaning.
The system is supplied with valves to direct the water flow. The water
may be directed to bypass the electrolysis chamber, to pass through the
chamber
to be oxygenated, or a separate line is provided to backflush the electrolysis
chamber to remove any minerals that may have accumulated in the vicinity of
the
electrodes.
Any embodiment is preferably supplied with fail-safe sensors, valves and
the like, devices known to those in the art. When the flow switch senses that
there is no water flow, the power is turned off. A temperature. sensor in the
electrolysis chamber shuts off current if the current is applied but no water
is
flowing. In that case, the temperature in the chamber rises and the
temperature
sensor will instruct the controller to cut the voltage. Likewise, relief
valves to
release fluid in case of liquid or gas pressure buildup may be located at any
point
in the system. A gas relief valve is best vented to the outside.
The- system includes an electrical circuit to control the activation of the
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emitters, to reverse polarity and to inactivate the emitters when water is not
flowing.
In an alternate embodiment, the oxygen is provided by bubbling it into a
chamber. In this embodiment, the oxygen can be supplied by tank or generated
on the site by PSA technology. The embodiment that comes closest to
approxirnating the result of the present invention is sparging oxygen through
a
microorifice in order to produce microbubbles of oxygen.
Water may contain many undesirable substances, such as iron,
manganese, arsenic, antimony, chrome and aluminum. The reduced salts are
generally soluble, while oxidized metals, such as Fez03 or MnOz are insoluble
and form fine precipitates. Reduced sulfur compounds, such as HZS, have a
noxious odor, while oxidized sulfur compounds are generally odorless. Other
undesirable siibstances include pesticide residues, drug metabolites and
bacteria.
In all embodiments, it is recommended to pass the effluent of treated water
through a final filter bed in order to remove fine precipitates and to improve
the
clarity of the water. Such filter beds are well known in the art and include:
Birm
filter, Greensand, Pyrolux. Filtersand, Filter-Ag, activated carbon,
anthracite and
gamet.
When the water is hard, that is, contains divalent metals such as calcium
and magnesium, the portion of the effluent intended to be heated, may pass
through a water softener.
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BRIEF DESCRIPTION OF 'THE DRAWINGS
Figure 1 shows a simple water treatment system.
Figure 2 shows a water treatment system with added safety devices and a
bypass.
Figure 3 is a diagram of the electric circuitry.
Figure 4 is a representation of various emitters.
Figure 5 shows an embodiment with two electrolysis chambers in series
and a final filter.
Figure 6 shows the preferred embodiment in a case with the electrolysis
chambers arranged in parallel.
Figure 7 shows the embodiment with oxygen bubbling or sparging.
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DETAILED DESCRIPTION OF THE INVENTION
In the following discussion, a water treatment system with three emitters
in one chamber is used as an example. The voltages and flow rates below are
suitable for this example, but it should be understood that more or fewer
cells can
be used, depending on the needs of the installation. It may be convenient to
pass
the water to be treated through a plurality of chambers to make a more compact
system or to treat large volumes of water. The chambers may be arranged in
series or in parallel. One of the pressing needs is the removal of ferrous
hydroxide, which has an odor, stains and fouls plumbing. Oxidized iron is non-
reactive and will not stain or foul plumbing, nor does it have an
objectionable
odor. The microbubbles evolved by the emitters are effective in rapid
oxidation
of contaminants both because of the high oxygen content achieved in the water
and because of the large surface area for reaction. A final filter is
preferred in
order to remove fine precipitates of oxidized iron and other oxidized metals
and
to improve the clarity of the water. In the following examples, specific
conditions of power supply, size and flow rates are provided for illustrative
purposes only. Those skilled in the art can readily make adjustments in power
supply, size and flow rates to provide the benefits of this invention.
Example 1. Experimental model
Turning to Figure 1, the intake 1 is attached to the water supply to be
treated. Valve 2 is shut; valve 3 is open to allow water into the electrolysis
chamber 4. When the flow switch 5connected to the controller 6 senses the
water
flow, the power supply 7 supplies voltage to the plates 8a, 8b and 8c, causing
oxygen to be evolved. The oxygenated water passes valve 9 to exit by the
outlet
10. Water pressure relief valve 11 and gas relief valve 12 will relieve
pressure in
the system. When the temperature sensor 13 senses an increase in temperature,
the controller 6 inactivates the plates 8a, 8b and 8c.
Turning to Figure 2 the intake 1 is attached to the water supply to be
treated. Valve 2 is shut; valve 3 is open to allow water into the electrolysis
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chamber 4. Valves 14 and 15 are closed. When the flow switch 5 connected to
the controller 6 senses the water flow, the power supply 7 applies voltage to
the
plates 8a, 8b and 8c, causing oxygen to be evolved. The oxygenated water
passes
by valve 9 to exit by the outlet 10. Pressure relief valve 11 and gas relief
valve
12 will relieve fluid pressure in the system when excess pressure is generated
and
detected by pressure gauge 16, a pressure switch 16a is activated. When the
temperature sensor 13 or pressure switchl6a senses an increase in temperature
or
pressure, the controller 6 inactivates the plates 8a, 8b and 8c. Connector 17
is
provided for ease of installation. Intake 18 is connected to the water supply.
When valve 14 and 15 are open and valves 3 and 9 are closed, water may be sent
in a backflush direction through the electrolysis chamber 4 and out outlet 19.
Either the embodiment in Figure 1 or the embodiment in Figure 2 may be
operated in several modes:
1. Bypassing the system: Valve 2 is open; valves 3 and 9 are closed. Water
flows from intake 1 to outlet 10, bypassing the emitters.
2. Through the system: Valves 3 and 9 are open; valves 2, 14 and 15 (Figure
2 only) are closed. Water flows from intake 1 through electrolysis chamber 4.
The flow switch 5 senses flow and controller 6 activates power source 7 to
supply current to the emitters.
3. Through the system with self-cleaning feature activated. Valves 3 and 9
are open; valves 2, 14 and 15 (Figure 2 only) are shut. The flow switch 5
senses flow and controller 6 activates power source 7. Controller 6
switches polarity as programmed. For intermittent use, it may be convenient
to program the controller to switch polarity each time water flow is started.
4. Backflush cycle, the model of Figure 2 only: Valves 14 and 15 are open,
valves 3 and 9 are closed. Water is introduced to the electrolysis chamber
through intake 18, flows in a retro direction through the chamber and out the
outlet 19. The electric circuitry is bypassed and adjustments are not
programmed, but are made manually.
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Example 2. Description of circuit operation
This description is based on a example system with three emitters and the
self cleaning polarity reversal on each initiation of water flow. Adjustments
can
be made for bigger or smaller systems. Circuit operation starts with applying
line
voltage, 120 V AC, to the power supply 26, which transforms the line voltage
to
12 V DC. The controller circuit is in electrical communication with flow
switch
23, temperature sensor 22 and push button switch 21 which activates the
circuit,
if the temperature sensor 22 indicates cool, thereby allowing 12 volts to be
applied to the push button switch 21. When this push button switch is pushed,
it
energizes relay 24 K1A. The connections on this relay are such that it remains
energized after the push button is released. The other contacts on this relay
look
at the flow switch to see if water is flowing. If so, the next relay 25 K1B is
energized, applying 120 V AC to the second power supply 20 and relay 27 K2.
K2 is a sequencing relay, the contacts of which will change state when
energized
and remain in an energized state when power is removed. The next time the
relay is energized, the contacts change state and then stay in that position.
When 120 V AC power is supplied to the power supply 20, it sends DC
voltage onto its output connections. Relays 28K3, 29K4, and 30K5 send the
current through terminal boards 31, 32 and 33 to the emitters. If K2 is in one
position, the voltage applied to the emitters is "forward" biased. The next
water
flow detection will change the state of K2 and the relays will change state,
resulting in a reversal of polarity on the emitters. Oxygen will be produced
during either state.
The action will continue indefinitely if the temperature sensor detects no
increase in temperature. If the sensor sees an increase in temperature above
its
set point, it will open the circuit and remove the 12 V DC power to the
relays,
thereby shutting down the circuit. The circuit can be restarted only by
activating
the button switch again. When the spigot is turned off, there is a slight
temperature rise until the flow switch turns off the controller. This rise is
not
enough to trigger the much higher set point on the temperature switch. Hence
the
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system will turn on again once the flow switch detects flow. The temperature
switch is a safety device and preferably, once the temperature switch
inactivates
the power system, manual intervention is required to reactivate the system.
Example 3. Emitter configurations.
Depending on the volume of fluid to be oxygenated, the emitter of this
invention may be shaped as a circle, rectangle, cone or other model. One or
more
may be set in a substrate that may be metal, glass, plastic or other material.
The
substrate is not critical as long as the current is isolated to the electrodes
by the
nonconductor spacer material of a thickness from 0.005 to 0.140 inches,
preferably 0.030 to 0.075 inches, most preferably 0.065 inches. Within this
distance, micro-and nanobubbles of oxygen are evolved. These bubbles are so
small that they cannot escape and build up into what may be termed a colloidal
suspension of oxygen in an aqueous medium. Oxygen concentrations of 260% of
calculated saturation at a particular temperature and =pressure have been
achieved
in a stationary container. The oxygen suspension in a flow-through unit can be
so
coricentrated with oxygen that the water appears milky. In addition to the
high
oxygen content achieved, the microbubbles have a larger surface area for
reaction
than ordinary-sized bubbles. While any configuration may be used in the water
treatment system, a funnel or pyramidal shaped cell was constructed to treat
larger volumes of fluid. Figure 4 shows a simple flat emitter 4A; a cone-
shaped
emitter 4B; and a rod shaped emitter 4C. Figure 4D depicts the most favored
configuration, a triple set of emitters arranged in a pyramidal configuration
in a
conduit. This flow-through ernbodiment is suitable for treating large volumes
of
water rapidly and is selected as the best mode for use in water treatment. It
should be understood that any configuration will be useful in the water
treatment
system and the system is not limited to the pyramidal configuration nor to
three
emitters nor to one chamber. In each of these configurations, the anode 34 and
cathode 35 are separated by 0.040 to 0.75 inches.
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Example 4. Operation of experimental systems.
A. An experimental system, such as that in Figure 1, was tested at a
home drawing water from a well 220 feet deep. The dissolved oxygen was
28.9 ~'o and iron content was between 2 and 2.5 ppm. The water had an
unpleasant smell and taste due to the iron and hydrogen sulfide content. The
system was activated and oxygen content of the outlet water was near 100%
saturation. Iron was reduced to less than 0.5 ppm and there was no unpleasant
taste or smell.
Calculations of power expended and cost thereof were made. The current
varied between 3.3 and 3.8 amps. At 12 volts, the power used was about 48
Watts for each emitter or about 144 watts. The system was activated for about
two hours each day, at a daily cost (current electric company rates) of about
3.4
cents per day.
This experimental system did not feature the self-cleaning reverse
polarity feature. The system was run for six days, during which time 1400
gallons of water was drawn. At this time, the electrodes began to show some
mineral deposits.
B. The first polarity-reversing experimental system, with three emitters,
was installed in a home provided with well water, containing 2 to 3 ppm iron.
The flow rate in the system was 6 gallons/minute. Polarity of the emitters was
reversed every time the flow was started, that is, when a faucet was opened,
about 70 times per day. This unit was equipped with a Birm filter. Tests
showed
complete removal of iron, down to 0 detectable ppm.
C. The second polarity-reversing experimental system was installed at a
site where the effluent was also used for irrigation. The water contained
12.75
ppm iron and operated at a 15 gallon/minute rate. Polarity was reversed every
time the well pump was started, which varied between 14 and 18 times a day.
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As for the prototype in Example B, the iron in the effluent was
undetectable and the effluent was passed through a Birm filter and the results
showed that iron levels were undetectable. These results were verified by an
independent testing laboratory.
D. The third polarity-reversing experimental system was installed at a
site where the water contained both 10 ppm iron and 2.25 ppm hydrogen sulfide.
Flow rate was 7 gallons per minute, and the polarity was reversed each time
the
well pump was started, about 14 times per day. The effluent was passed through
a greensand filter. Iron and hydrogen sulfide levels in the effluent were
undetectable.
Example 5. Laboratorv testing of 4.0-5.0 ppm iron
A. Seventy gallons of well water testing 4 to 5 ppm were passed through
conduit equipped with a three plate, twelve-inch emitter at 12 Volts. The flow
rates were varied and the iron content was measured after the effluent passed
through a 9 by 48 inch Birm filter. The first flow rate tested was two gallons
per
minute. Iron content was below 0.5 ppm (the practical lower limit of
measuring).
When the flow rate was increased to 2.7 gallons per minute, the iron content
was
less than 0.5 ppm. The flow was increased to 4.87 gallons per minute and then
to
six gallons per minute. The iron content of the effluent was 0.5 ppm or below.
B. Trailer testing. A special 5 ft. by 8 ft. trailer was outfitted in order to
conduct water testing at various sites and to verify results before units were
installed. The trailer was equipped with two polarity-reversing oxygenator
chambers, a power supply, and two Birm filters. A 14 inch by 65 inch Birm
filter
for lower flow rates and a 21 inch by 54 inch Birm filter for higher rates
were
used. The trailer had its own power generator and large flow pump so iron,
hydrogen sulfide and manganese removal can be tested inunediately on site.
With this trailer, the ability of the system to remove manganese was
tested. At the City of Brooklyn Park,lblinnesota, various wells tested between
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1.3 ppm to 2.7 ppm manganese. With the two chambers, powered on the trailer,
and at flow rates up to 10 gallons/niinute, the manganese was oxidized and
100%
removed by the 21 by 54 inch Birm filter.
Example 6. Compact unit with self- cleaning feature.
New embodiments have been developed that are suitable for factory
assembly into a compact unit within a case for convenient installation. The
improved features include a self-cleaning feature. Figure 5 shows a typical
system for assembly on site. In this example, six sets of emitters are
provided,
three in each of two electrolytic chambers 36 A and 35B, with a 12 V DC power
source. The chambers in this embodiment are arranged in series. In this
embodiment, when raw or untreated water enters the chamber 36A at the water
input 37, a flow switch connected to the control box 38 is activated. The
control
box is shown in detail in Figure 3. The flow switch is-calibrated to sense
water
flow at or above a preset flow, preferably 0.5 gallons per minute. When flow
is
sensed, the flow switch sends a signal to the power supply box in the control
box
38, which in turn applies 12 V DC power to the emitters in the chambers 36A
and
36B. The effluent leaves chamber 36A and enters chamber 36B. Following
oxygenation, the effluent then passes by control and safety devices 39, 40,
41, 42
and 43 and thence into the filter 44. As water passes down to the bottom of
the
filter 44, it is drawn up through an internal conduit (not shown) and to the
output
45.
Figure 6 shows a compact system that can be factory-assembled. The
system has two chambers 46A and 46B, arranged in parallel and fitted into a
case
47. The case is a compact enclosure containing both plumbing and electrical
components. The water enters at input 48 and then passes by the input side of
a backflow preventer 49, splitting into parallel paths and through the
electrolytic
chambers 46A and 46B where it is oxygenated. The oxygenated water then
recombines in the upper manifold 50 and is routed out of the output side 51 of
the
bypass valve 52. The effluent is finally passed out of the case into a final
filter as
in Figure 5.
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It should be noted that the details of the elements of the water treatment
system are more fully descrhbed in examples 1 to 4. The embodiments described
in this example 6 are equipped with a polarity reversing control. The process
continues as long as the water flow exceeds the preset flow.
Example 7. Bubbling or sparging with oxy'gen.
As mentioned above, it is well-known to attempt to improve the quality of
water by aeration. Previous techniques of bubbling air or oxygen were not
effective in reducing metals and sulfur compounds. Whi1e the embodiments
descri7aed above produce the most improvement in quality of water, other means
may produce an approximation of those resu-lts. Technology exists to bring
pure
oxygen to a site and inject it into the water in the form of microbubbles,
which
raises the oxygen content of the water and also presents a greater surface
area for
reaction with undesirable substances. A tank of oxygen may be used. The PSA
methods passes air through a filter that removes the dinitrogen, leaving pure
oxygen. Figure 7 shows a diagram of a simple bubbling embodiment. Oxygen
from tank 53 is sparged into a simple chamber 54 with a static mixer 55
through
a microorifice 56 in order to produce microbubbles to raise the oxygen content
above the content calculated to be 100% saturation at the pressure and
temperature of the chamber. Metals and other contaminants are oxidized.
Microbubbles, with increased surface area for reaction, can be produced by
sparging air or oxygen through a microorifice. Oxygen is preferred. Such a
microorifice is described in United States Patent Number 6,394,429, the
teachings of which are incorporated by reference. The bubble chamber is
preferably provided with a means to direct the bubbles throughout the chamber
rather than rising in a stream to the outlet. The means can be inert particles
or
more preferably, a static mixer, such as that sold by Koflo Corporation (Cary,
IL)
or Chemineer (Dayton, OH). A static mixer 55 is, generally, a series of vanes
or
paddles that disrupt the flow of bubbles to ensure mixing. In this schematic
diagram, the outfZow from the chamber 54 is shown entering through connection
57 to the top of filter 58. In practice, the effluent enters at the top of the
filter
tank and an internal conduit (not shown) draws it down through the filter.
Water
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enters the system at inlet 59.
ExaMle S. Activation of polarity reversal
Various embodiments of emitter were tested. Round, ftat or pyramid
configuration emitters were tested in the laboratory for over 30 days. The
emitters chosen were of titanium. The current was switched at varying
intervals
from five seconds to three hours. No buildup of mineral deposits was observed.
Depending on the site and the user's preference,,in the functioning water
treatment system, the polarity can be set to reverse:
= each time the well pump turns on and the water pressure increases;
= when the water flow is initiated;
= at timed intervals from 45 seconds to 24 hours or more;
= or manually.
Each choice has its advantages with the purpose of minimizing the
frequency of reversing polarity in order to prolong the useful life of the
electrodes while maintaining the efficacy of water treatment. In general, if
the
water use is constant, the timing mode can be selected. When water use is
intennittent, as is generally the case with home use, a mode based on pump or
water flow is preferred.
Those skilled in the art may readily make insubstantial changes or
additions. Such changes or additions are within the scope of the appended
claims.
