Water softener abstract
A method of reclaiming brine waste in a water softener having an
inlet, a service water outlet, a wastewater outlet, and having a
brine/rinse cycle in which brine solution is directed through a
resin bed and to a drain, includes measuring a TDS or specific ion
level of the solution exiting the wastewater outlet during the brine/rinse
cycle, comparing the measured TDS or specific ion level with a preset
value, and diverting the flow of water out the outlet to a reclamation
location once the measured TDS exceeds the preset value. A waste
reclamation unit includes a housing in fluid communication with
the water softener and at least one waste reservoir, a compressor,
a compressor coil, a control unit configured for sensing the introduction
of liquid into the reservoir and for triggering the compressor;
and a collection pan configured for collecting water condensing
on the coil and preventing the entry of water into the waste reservoir.
Water softener claims
1. A method of reclaiming brine waste in a water softener having
an inlet, a service water outlet and a wastewater outlet, the operation
of the softener including a brine/rinse cycle in which brine solution
is directed through a resin bed of the softener to the wastewater
outlet and ultimately to a drain, said method comprising: measuring
a TDS or specific ion level of the solution generally adjacent the
wastewater outlet during the brine/rinse cycle; comparing the measured
TDS or specific ion level with one of a preset value and a value
determined from the inlet water; and diverting the flow of water
out the wastewater outlet away from the drain to a reclamation location
once the measured TDS exceeds the preset value.
2. The method of claim 1 further including continuing the measuring
of the TDS or specific ion level of the solution generally adjacent
the wastewater outlet and diverting the flow until the measured
TDS or specific ion level falls below the preset value.
3. The method of claim 1 wherein the water softener includes a
brine tank, and further including monitoring a brine front in the
treatment tank, and diverting the water flow from the outlet to
the brine tank approximately when the brine front reaches the outlet.
4. The method of claim 3 further including continuing the measuring
of the TDS or specific ion level of the solution exiting the wastewater
outlet and diverting the flow until the measured TDS or specific
ion level falls below the preset value, then sending the flow to
drain.
5. The method of claim 1 further including evaporating the water
from the solution at the reclamation location.
6. The method of claim 5 further including sensing the presence
of the solution at the reclamation location, energizing a compressor
to cool a condensing mechanism, heating the solution with heat generated
by the compressor, and collecting water condensing upon the condensing
mechanism.
7. The method of claim 6 further including sensing the completed
evaporation of the diverted solution and deenergizing the compressor.
8. The method of claim 6 further including collecting the remaining
solids for disposal.
9. The method of claim 1 further including providing one of TDS
level determination using sensing and reference electrode pairs
for monitoring TDS level of the water exiting in the softener as
waste.
10. The method of claim 1 wherein said reclamation location is
a brine tank.
11. The method of claim 1 wherein said reclamation location is
a storage tank where the liquid is collected and taken to an alternate
location for treatment and disposal.
12. A waste reclamation unit configured for use with a water softener
for reclaiming high TDS solution and preventing the discharge of
that solution to drain, said unit comprising: a housing in fluid
communication with the water softener and including at least one
waste reservoir; a compressor associated with said housing and including
at least one coil; a control unit associated with said housing and
configured for sensing the introduction of liquid into said reservoir
and for triggering said compressor; and a collection pan disposed
in operational relationship to said at least one coil and configured
for collecting water condensing on said at least one coil and preventing
the entry of said water into said waste reservoir.
13. The unit of claim 12 wherein said housing includes separate
waste reservoir and compressor chambers respectively for said reservoir
and said compressor, and further including means for transferring
heat generated by said compressor into said waste reservoir chamber.
14. The unit of claim 13 wherein said means for transferring heat
is a fan, an infrared heater, a heat lamp, a heating pad, a ceramic
heater, or heating strips/tape.
15. The unit of claim 12 further including an outlet on said housing
in fluid communication with said collection pan.
16. The unit of claim 12 wherein said at least one coil and said
collection pan are disposed in said housing above said waste reservoir.
17. The unit of claim 12 wherein said at least one waste reservoir
is removable.
18. The unit of claim 17 wherein said at least one waste reservoir
is disposable.
19. The unit of claim 12 further including a supplemental removable
waste reservoir.
20. The unit of claim 12 further including an overflow or reservoir
full sensor configured for sensing the level of liquid or solids
in said at least one waste reservoir and energizing at least one
of an alarm signal and a cutoff signal to the softener.
Water softener description
BACKGROUND OF THE INVENTION
[0001] The present invention relates generally to water treatment
devices such as water softeners, and particularly to a system for
reducing the amount of wastewater having a high total dissolved
solids (TDS) concentration which is typically sent to the drain
during the operation of the water treatment device.
[0002] Hard water causes problems such as scaling, spotting, soap
scum, irritated/dry skin, poor laundry performance and others. Ion
exchange water softeners are used to remove calcium (Ca.sup.++)
and magnesium (Mg.sup.++), commonly known as the "hardness"
elements for the hard scale deposits they can cause. Softeners do
this using the natural preferential exchange of sodium (Na.sup.+)
or potassium (K.sup.+) ions for those of the hardness elements.
It is also possible to use this process for the removal of other
troublesome multi-valent ions such as iron (Fe.sup.++) and manganese
(Mn.sup.++). Once the sodium ions have been exchanged off the resin
by the hardness ions (given up their site to the more highly charged
ions), the softener needs to have this naturally preferred process
reversed. This is accomplished by overcoming the naturally favored
exchange by using a large excess of sodium or potassium ions to
drive the reaction the other way. As a constant flow of excess sodium
or potassium ions moves through the ion exchange resin bed, the
hardness elements are pushed off as waste along with the excess
sodium or potassium. Finally, as the resin is rinsed, the resin
exchange sites each hold one sodium or potassium ion. The equipment
is then returned to service for the reduction of more hardness ions.
[0003] Theoretically, it is possible to regenerate every exchange
site on the resin by using large amounts of salt, resulting in an
absolute maximum capacity. Practically, this is not done because
the amount of regenerating salt that would be required is excessive
compared to the gain in capacity. Efficiency is measured by determining
the amount of hardness removed for each pound of salt used to regenerate
it back to the sodium or potassium form. During regeneration, each
pound of salt used is increasingly less effective than the previous
one. Modern ion exchange softeners are regenerated at dosages intended
to be efficient rather than for the most hardness removed per regeneration.
Equipped with demand type regeneration devices and adjusted for
the most efficient salt dosages, they can be designed to reach over
70% of maximum theoretical capacities.
[0004] In 2002 California law required new softeners to have an
efficiency rating of 4000 grains hardness removed for each pound
of salt used in regeneration, up from averages of only 2000 grains
for softeners in the 1980s into 1990s. Even with these substantial
gains in efficiencies and the resulting decrease in the amount of
high TDS wastewater discharged during regeneration, some municipal
systems are unable to allow this increase in the TDS of their wastewater.
This can be due to waste treatment plant discharge permits or the
intended uses for reclaim water such as irrigation of sensitive
crops. Some areas have banned self-regenerating water softeners.
[0005] Most of the research efforts to date on a "saltless"
water softener have involved total dissolved solids ("TDS")
reduction processes like reverse osmosis, nanofiltration, distillation,
continuous deionization, capacitive deionization, or others. These
processes do reduce hardness, but they are not selective for hardness
like the ion exchange process. They also reduce other dissolved
solids present along with the hardness elements. Therefore, all
of these TDS reduction processes are limited in the amount of product
water they can recover due to the water chemistry of the influent
supply. The solubility of the various dissolved ion species present
in the feed water will determine how much reduced TDS product water
can be recovered before precipitation will occur, causing scale
to form. In a reverse osmosis system, the precipitation would cause
a failure. On some feed water sources it may only be possible to
recover 50% as product water without causing precipitation to occur.
The advantage of these TDS reduction systems in reducing hardness
without the use of salt is compromised by the issues of water conservation
and cost. There have also been recent concerns about the TDS concentrated
in the waste stream created by these processes.
[0006] Water demands in a household environment are sporadic. There
are periods of high demand for showers, laundry, dishwashing, etc.
and long periods of no demand. TDS reduction systems proposed for
household use would need to be relatively large, complex and expensive
to meet peak demand flow rates. Due to these design requirements
and inherent drawbacks of large on-demand systems, most designs
have typically been storage and repressurization systems. The latter
system treats water and transfers it into a large reservoir that
is then used to deliver product water at the required demand rates.
[0007] As discussed above, a water softener reduces hardness by
exchanging one ion for another. In the case of current water softening
technology, this means the exchange of sodium or potassium ions
on the resin contained in the softener tank for the incoming calcium
or magnesium "hardness" ions. This process is an equal
charge-for-charge exchange. The TDS level of the feed water and
the product water are essentially the same, only the mix of ions
present has been changed. The water has been "softened"
now that the "hardness" ions have been removed. In the
service cycle, a water softener recovers 100% of the feed water
as product water. Only the backwash/brine/rinse cycles used to renew
the resin exchange sites in the regeneration cycle produce any wastewater.
The overall product water recovery of the service/regeneration cycle
is typically over 90% and often over 95% depending on the incoming
hardness level and the design of the system. A softener also handles
the wide range of water flow demands in a household environment
without the need for a storage and repressurization system.
[0008] Alternate hardness reduction technologies have been researched,
tested and applied. None of these processes have been shown to be
as effective, safe, reliable, or economical as ion exchange water
softening. The weakness of ion exchange softeners, and the reason
for legislation against their use in some communities is the high
TDS of the regeneration waste. It is not a health hazardous waste;
rather it is only too salty for some secondary uses such as irrigation
or for discharge to sensitive streams. Different secondary uses
and different communities may have different maximum allowable TDS
discharge levels.
[0009] Thus, there is a need for a brine waste treatment system
for use with a water softener which reduces or eliminates the release
of high TDS regeneration water to drain. There is also a need for
such a system where the apparatus requires limited floor space and
is relatively inexpensive. Such an apparatus may also be considered
for installation indoors or outdoors.
BRIEF SUMMARY OF THE INVENTION
[0010] The above-listed needs are met or exceeded by the present
system for water softener brine waste recovery, which features a
method and apparatus for treating the liquid brine waste from a
self-regenerating household water softener for disposal. The invention
uses the system of evaporation and condensation in the preferred
embodiment, to separate water from an undesirable solid. The high
TDS liquid waste is processed into a solid form that can be disposed
of as common household refuse. Ideally, a user places regeneration
salt in one container and removes hardness and sodium salt solid
waste from another container.
[0011] The present system will prevent the potential overloading
of downstream waste treatment processes with high liquid TDS levels
during regeneration, particularly sodium or potassium chloride salts.
Further, the present system will enable the use of effective hardness-reducing,
ion exchange water softening equipment, even in areas currently
troubled with a high TDS load in wastewater.
[0012] More specifically, the present invention provides a method
of reclaiming brine waste in a water softener having an inlet, a
product or service water outlet and a wastewater outlet, the operation
of the softener including a brine/rinse cycle in which brine solution
is directed through a resin bed of the softener to the wastewater
outlet and ultimately to a drain. The method includes measuring
a TDS or specific ion level of the solution generally adjacent the
wastewater outlet during the brine/rinse cycle, comparing the measured
TDS or specific ion level with a locally required maximum preset
value or a value determined from that of the inlet water, and diverting
the flow of water out the wastewater outlet away from the drain
to a reclamation location once the measured TDS exceeds this desired
or preset value. Alternately, TDS levels may be interpreted from
signals given by a pair of conductivity sensors located inside the
softener near the bottom of the resin bed.
[0013] In addition, a waste reclamation unit is provided for use
with a water softener for reclaiming high TDS regeneration solution
and preventing the discharge of that solution to drain. The unit
includes a housing in fluid communication with the water softener
and including at least one reservoir, a compressor associated with
the housing and including at least one coil, a control unit associated
with the housing and configured for sensing the introduction of
liquid into the reservoir and for triggering the compressor; and
a collection pan disposed in operational relationship to the at
least one coil and configured for collecting water condensing on
the at least one coil, directing the low TDS condensed water to
drain and preventing the re-entry of evaporated/condensed water
into the reservoir.
[0014] Further, the present system provides for redirecting very
low hardness brine at the end of a regeneration cycle back to the
brine making system. This reclamation of regenerant brine can reduce
the volume of liquid high TDS solution to be treated by the waste
brine system. However, the practice of redirecting brine for reuse
may be accomplished independently of the waste brine system to save
salt, improve softener regeneration efficiency and reduce high TDS
waste to drain.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0015] FIG. 1 is an elevational view of a conventional water softener
system suitable for use with the present brine reclamation system;
[0016] FIG. 2 is a fragmentary schematic vertical section of a
first embodiment of the present brine reclamation device;
[0017] FIG. 3 is a front view of the device of FIG. 2;
[0018] FIG. 4 is a rear view of the device of FIG. 2; and
[0019] FIG. 5 is a fragmentary elevational view of an alternate
embodiment of the present brine reclamation system.
DETAILED DESCRIPTION OF THE INVENTION
[0020] Referring to FIG. 1 a water conditioning or softening apparatus
suitable for use with the present system is generally designated
10 and includes a water tank or main treatment tank 12 containing
a bed 14 of suitable ion exchange resin. In the service cycle, a
water supply line 16 is connected via a valve housing 18 which passes
the water into the tank 12. The water is softened as it passes down
through the bed 14 and is removed via a pipe 22 through the valve
housing 18 to a line 24 which supplies the softened water to the
water system. A conduit 26 extends from the valve housing 18 to
a brine tank 28 which contains salt and water for forming the brine.
A drain conduit 30 is also connected to the valve housing 18 and
is connected to a suitable drain (not shown). A control unit 32
is mounted adjacent the valve housing for controlling the operation
of the valve which diverts water as required during operation of
the softener 10. As is typical in such control units, a microprocessor
34 (shown hidden) is included in the control unit 32.
[0021] As is well known in the art, the softener 10 operates most
of the time in a service cycle, in which feed water flows through
the resin bed 14 and is softened. Softened water is emitted out
the line 24. After a certain amount of water has been softened,
set by the user based on consumption rates, hardness of feed water,
and other factors known to those skilled in the art, the resin bed
14 must be regenerated to discharge the hardness ions collected
on the resin beads and replaces them with sodium or potassium ions.
[0022] The following describes a typical regeneration sequence
for a water softener. First, a backwash step is conducted, in which
feed water enters the tank 12 in reverse direction to flush out
particles filtered in the service cycle and to loosen the resin
bed 14 so that it is not overly compacted. The next step is brine/draw
and brine/rinse. This step has two functions. The first is to introduce
brine into the treatment tank 12 from the brine tank 28 via the
conduit 26. Brine is drawn into the treatment tank 12 for a number
of minutes or until a mechanical brine valve (not shown) in the
brine tank 28 discontinues the brine draw. At that time, a slow
rinse cycle begins. The resin bed 14 of the water softener 10 is
surrounded totally by sodium or potassium ions. As hard water used
in the slow rinse enters the tank through the conduit 16 it starts
to form a low sodium/high sodium front at the top of the tank 12.
This front will gradually advance downward towards the bottom of
the tank 10 pushing the high TDS liquid out.
[0023] As is described in commonly assigned U.S. Pat. No. 5699272
incorporated by reference herein, pairs of sensing and reference
electrodes 36 38 connected to the microprocessor 34 can be used
to monitor the progress of the front towards the bottom of the tank
12. The electrode pairs 36 38 are vertically spaced relative to
each other for detecting the impedance difference of the solution
in the water tank between the electrodes 36 which form a sensing
cell Rs and the electrodes 38 which form a reference cell Rr. The
monitoring of this front is preferably used to determine when the
slow rinse cycle has concluded. It will also be noted that the electrodes
38 are in close operational proximity to a lower end of the conduit
22 through which flows both treated water out conduit 24 and water
intended for the drain through conduit 30 depending on the position
of the valve in the valve housing 18. Upon conclusion of the slow
rinse cycle, a fast rinse/refill cycle is completed and the softener
10 returns to the service cycle. However, as described below, the
signals from these electrodes 36 38 may also be used to monitor
the TDS level of the water in the tank 12. The rinse out of high
TDS solution may also be monitored with a conductivity sensor 42
located in drain conduct 30.
[0024] A typical household water softener with one cubic foot of
ion exchange resin produces 40-75 gallons of liquid to drain per
regeneration. The regeneration frequency of a softener is dependent
on water use and hardness, but typically occurs 1-2 times a week.
The challenge is to control the type and amount of liquid waste,
thereby reducing the volume of high dissolved solids water to be
treated for disposal.
[0025] To characterize the liquid waste produced by a typical softener,
the amount and chemistry of each regeneration step must be analyzed.
Although the exact flow rates, timing and order of regeneration
steps vary between systems designs, the following descriptions are
typical for a 1 cubic foot system:
1 FLOW RATE TO STEP TIME Gallons per DRAIN TDS LEVEL NAME Minutes
Minute Gallons PPM Backwash 5-10 1.5-2 7-20 Same as inlet Brine
Draw 20-40 0.3-0.5 5-20 Same as inlet, increasing to High Rinse
20-30 0.4-0.5 8-15 High, then declining to same as inlet Final Rinse
5-10 1.5-2 7.5-20 Same as inlet
[0026] Control of each cycle and sending acceptable TDS liquid
directly to drain without treatment reduces the cost/size of the
waste treatment system. There is little or no impact on the incoming
TDS level for the regeneration waste produced in the Backwash or
the Final Rinse steps. These steps and their associated liquid volumes
could be controlled to discharge directly to drain since there is
no TDS concentration occurring. That leaves only the 13-35 gallons
of liquid waste produced in Brine Draw and Rinse to control/treat.
It is anticipated that improvements in regeneration efficiency could
further reduce this volume.
[0027] An analysis of the TDS levels at drain during these steps
shows that there is a lag before the high TDS liquid gets to the
drain at the start of Brine Draw. This is due to the displacement
of the water already in the resin tank. Conventional water softeners
continue to send this liquid with an acceptable TDS level to the
normal household drain. Effective monitoring and control of the
wastewater will result in less liquid to handle with the brine waste
treatment system.
[0028] Referring now to FIGS. 2-4 to minimize the amount of high
TDS level water to drain, the present system, generally designated
40 provides a way for the undesirable high TDS wastewater to be
diverted from the household drain, stored and concentrated for separate
disposal as household refuse. TDS values are preferably interpreted
from the signals given by the electrode pairs 36 38 as described
above, which are also connected to the microprocessor 34. A diversion
threshold value may vary to suit the application, or the regulations
of a specific locality. Alternately, a TDS sensor or an ion specific
electrode 42 is placed in the conduit 30 where it exits the valve,
through which water will flow to the drain outlet 30. This sensor
42 is connected to the microprocessor 34 which measures sensed
TDS or specific ion values and compares them with preset values,
as is known in the art.
[0029] At a point in the Brine Draw step when the TDS or specific
measured ions exceeds the diversion threshold or the acceptable
limit of TDS in the softener discharge, the controller 32 and specifically
the microprocessor 34 will signal a drain valve 43 and a divert
valve 45 to divert the high TDS liquid from the softener 10 into
the present waste reduction device 44 which serves as the brine
reclamation location. This diversion to the device 44 continues
as long as, and until the control 32 senses, through the signals
from the electrodes 36 and 38 or the sensor 42 a return to an acceptable
discharge TDS level.
[0030] An advantage of the present system 40 is that using the
electrodes 36 and 38 or the sensor 42 with the control 32 to only
divert the high TDS regeneration waste for treatment, reduces the
total volume of liquid that requires treatment for alternate disposal.
Only the lower TDS water from the regeneration steps that is not
a burden to the downstream waste treatment plant or the environment
is released to the drain.
[0031] The basic function of the waste reduction device 44 is to
evaporate the water from the collected high TDS material. This serves
to concentrate the remaining solids so that they can easily be discarded.
To achieve these goals, the device 44 includes a housing 46 having
an inlet 48 in fluid communication with the drain conduit 30 of
the water softener 10. The housing 46 defines a reservoir chamber
50 configured for retaining at least one removable, and preferably
disposable reservoir 52. A compressor 54 is preferably associated
with the housing 46 and in the preferred embodiment is located
in a compressor chamber 56 adjacent, but separated from, the reservoir
chamber 50. A partition 58 separates the compressor chamber 56 from
the reservoir chamber 50. An aperture 60 in the partition 58 is
provided with a fan 62 disposed to vent hot air from the compressor
chamber 56 into the reservoir chamber 50. This venting enhances
the evaporation of the liquid in the reservoir 52.
[0032] At least one compressor coil 64 is connected to the compressor
54 as is known in the art and is preferably disposed above the reservoir
52. Separating the coil 64 from the reservoir 52 is a collection
pan 66 disposed to collect low TDS water droplets condensing upon
the coil 64. The pan 66 is preferably inclined so that collected
water may be removed via a discharge outlet 68. As best seen in
FIG. 3 it will be appreciated that the pan 66 is narrower than
the housing 46 to allow for the free flow of water vapor upward
towards the coil 64. It is also contemplated that the discharge
outlet 68 is connected to drain, however it is also contemplated
that a collection container (not shown) may be provided for retaining
and reusing the low TDS condensed water. The latter essentially
is now distilled water. It is also anticipated that a reclamation
system could be located outside in some geographical regions. Such
system may not require a compressor and coils since the evaporated
water vapor could be released directly to the atmosphere.
[0033] A liquid sensor 70 serves as the reservoir control unit,
is disposed in operational relationship to the reservoir 52 and
monitors the presence of liquid or solids build-up in the reservoir.
Suitable liquid sensors 70 include float switches, optical switches,
spring-loaded weight switches or other types of sensors capable
of generating a signal upon the presence of liquid or a solids build-up
in the reservoir 52. The compressor 54 may be alternately be energized
by the control unit 32 upon water being diverted from the drain
conduit 30 and into the inlet 48. Also, the reservoir 52 is preferably
sized to accommodate in excess of the amount of solution generated
during the cyclical diversion, which is expected to be in the range
of 10-20 gallons.
[0034] Typically high TDS liquid diverted from the softener tank
12 travels through the drain conduit 30 is diverted by the valves
43 and 45 under the control of the microprocessor 34 (signaled by
the TDS sensor 42 or the electrodes 36 and 38) to the inlet 48 and
ultimately into the reservoir 52. Upon entry into the reservoir
52 the liquid sensor 70 or the microprocessor 34 energizes the
compressor 54 which then cools the at least one coil 64. In so doing,
the compressor 54 generates heat, which is preferably passed by
the fan 62 into the reservoir chamber 50 to enhance the evaporation
of the liquid from the reservoir 52. It is contemplated that other
sources of heat or other evaporation enhancers 51 (FIGS. 2 and 3)
may be provided, including but not limited to solar heaters, exhaust
fans, incandescent bulbs, heater coils and the like. The water vapor
emitted by the reservoir condenses on the coil 64.
[0035] Once the solution in the reservoir 52 is evaporated, which
can be determined by the humidity level inside the housing 46 the
weight of the reservoir, the level of a float switch, the optical
density of the contents of the reservoir, the passage of time or
other known technique, the compressor 54 is deenergized. The remaining
solids are collected in the reservoir after successive cycles, and
preferably disposed of as a solid with normal household refuse.
It is contemplated that the collected solids may be emptied from
the reservoir 52 for disposal, or that the entire reservoir is disposable.
[0036] An optional overflow or reservoir full sensor 72 (FIG. 2)
may be provided with, or in operational proximity to the reservoir
52 to gauge the flow of liquid in the brine inlet 48 or gauge the
need for the reservoir 52 to be replaced/emptied. Upon triggering
of the sensor 72 the flow from the treatment tank 12 is terminated,
or the regeneration step is cancelled. Furthermore, the overflow
sensor 72 may be connected to a visual and/or audible alarm (not
shown). An overflow outlet 74 is provided for draining excess water
which may spill over the reservoir 52. A return air screen 75 may
be provided to stabilize airflow between the compressor chamber
56 and the coils 64.
[0037] Referring now to FIG. 5 another embodiment of the reclamation
device is generally designated 80. Shared components with the reclamation
device 44 have been designated with the same reference numbers.
Also, it is contemplated that the devices 44 80 may each include
equipment and/or features described for the other in the present
application. The main difference between the device 80 and the device
44 is that a generally "L"-shaped housing 82 has been
provided for a more compact arrangement of the components. Such
a model could be used where household space is at a premium.
[0038] A rotary or "squirrel cage" fan 84 is located
at an upper end 86 of the housing 82 and pulls air through the device
past warm coils 88. The warmed air aids in the evaporation of the
waste brine in the two reservoirs 52 52a. The use of one reservoir
52 is also contemplated, and it is also contemplated that the device
may have multiple reservoirs. A conventional "Y" diverter
fitting 90 may be used to alternate flow to either reservoir 52
52a. Upon becoming filled with the collected sediment, the reservoirs
52 52a may be removed from the chamber by a lateral, drawer-like
sliding action or removed through an opening in the top of the device.
[0039] Below the fan 84 is an inclined cooling panel 92 bearing
the coil 64. The warmed moist air condenses on the coils and collects
in a pan for disposal through discharge outlet 68. In this embodiment,
the compressor 54 is located external to the device 80 or beneath
the cooling panel 92. It will be appreciated that other configurations
of these components may be provided and still achieve the benefits
of the collection, evaporation, condensation and reclamation of
water and solids from softener regeneration discharge.
[0040] Another aspect of the present system relates to the previously
described characteristics of the various waste solutions coming
from the softener during regeneration. As has been noted, as the
brine solution first enters the treatment tank 12 the first liquid
to waste is treated water. The next liquid component is mixed brine
and the discharged calcium and magnesium ions. This component is
the prime object of the present diversion reclamation system, since
it has the highest undesirable TDS levels and dislodged hardness
levels. The last part of this brine component is disposed behind
a brine front and is relatively hardness-free, pure sodium or potassium
chloride, since the resin media 14 has been regenerated at this
point and cannot take up any more sodium or potassium ions. Further,
the calcium and magnesium ions have been substantially eliminated.
[0041] To reduce the amount of liquid sent to the reclamation unit
40 and also to prevent the discharge of this substantially pure
brine to drain, it is contemplated that the present system is configurable
for conservation of the brine. Specifically, the brine front BF
(FIG. 1) is monitored in the tank 12 and, upon the front reaching
the bottom of the tank, the drain conduit 30 is connected, as by
a diverter valve 94 under the control of the control unit 32 to
the brine tank 28 for reuse in the next regeneration. In this manner,
the salt consumed by the softener 10 is also reduced.
[0042] One way in which the movement of the brine front BF is monitored
is by the electrodes 36 38 which sense the change in conductivity
of the two solutions, first the high TDS calcium, magnesium and
brine regeneration solution, and second, the relatively low TDS
brine solution. The TDS or specific ion monitor 42 may also be considered
as a technique for monitoring when diversion should be initiated.
The diversion to the brine tank 28 continues until the desired amount
of liquid has been returned. If the electrodes 36 and 38 or the
TDS or specific ion sensor 42 sense that the TDS of the outgoing
solution is then below the acceptable discharge level, it is diverted
directly to the drain through valve 43. If an acceptable level has
not been reached, the wastewater is then diverted to the present
waste reclamation system 40 through the valve 45 until an acceptable
level is achieved.
[0043] It is obvious that any steps taken to reduce the amount
of liquid diverted to the invention would reduce the time/energy
needed to turn it into a disposable solid. Optimization of resin
tank design, distribution, brine flow rates, brine strengths times,
steps, resin types would all enhance the value and performance of
this system.
[0044] One concept would be the use of higher concentration brine
for regeneration. Salt dosages used in conventional softeners are
fine-tuned to meet brine regeneration efficiency requirements. With
the present device, it may be more energy and cost efficient to
focus on reducing the amount of liquid to treat due to low cost
and availability of salt. The cost of removing the water from the
high TDS waste may exceed the cost of using additional salt. A balance
between the cost of waste disposal and the gallons of product water
provided per pound of salt used would need to be examined. With
this invention, any additional salt used in an effort to reduce
liquid volume is efficiently disposed of as a solid and not released
to any downstream wastewater treatment plants.
[0045] The goal of treating the high TDS waste from the regeneration
of a water softener is to finish with a safely disposable solid.
The water needs to be selectively removed from the solids dissolved
in it. A number of options in an industrial or municipal application
involve the use of hazardous chemicals, precipitation, filter presses,
waste heat, and others. These are not realistic options for use
in a household environment. The process needs to be simple and cost
effective.
[0046] The present system uses the processes of evaporation and
condensation to first separate and then capture the water portion
of the softener regeneration waste. This condensed low TDS wastewater
can be safely released to drain, and the resulting solid waste product
left behind after evaporation can be disposed of as normal household
waste. In addition, the present system can be sized to provide the
separation of the anticipated waste volume to the number of days
between regeneration. Therefore, if the softener only produces 15
gallons of waste every 4-5 days, the present system could be sized
to have 2-3 days of time to evaporate/condense and recover the water
to drain from the waste. This would mean smaller and more cost efficient
systems could be used.
[0047] While a particular embodiment of the present system for
reclaiming water softener brine waste has been described herein,
it will be appreciated by those skilled in the art that changes
and modifications may be made thereto without departing from the
invention in its broader aspects and as set forth in the following
claims. |