U.S. patent application number 10/619671 was filed with the patent office on 2004-01-15 for wastewater containment and treatment methods and apparatus.
Invention is credited to Price, Elbert Glen, Roach, Gary W..
Application Number | 20040007534 10/619671 |
Document ID | / |
Family ID | 28042346 |
Filed Date | 2004-01-15 |
United States Patent
Application |
20040007534 |
Kind Code |
A1 |
Roach, Gary W. ; et
al. |
January 15, 2004 |
Wastewater containment and treatment methods and apparatus
Abstract
Superabsorbent polymers (SAPs) are used for the containment and
treatment of wastewaters. SAPs are mixed with a wastewater in
amounts sufficient to absorb substantially all of the wastewater
and prevent it from leaving a defined containment area. The water
can then be evaporated from the SAP to produce a substantially dry
polymer composition containing the SAP and the wastewater
contaminants. The dry polymer composition is discarded or, when
appropriate, used as a fertilizer for plants. Surprisingly, the SAP
reduces the odor associated with ammonia containing wastewaters by
binding to the ammonia and reducing the ammonia gas present in the
airspace around the wastewater. The evaporation process may be
conducted in the presence of a heat exchanger to produce cool,
fresh air that is used to cool facilities, particularly animal
rearing and production facilities.
Inventors: |
Roach, Gary W.; (Midwest
City, OK) ; Price, Elbert Glen; (Anadarko,
OK) |
Correspondence
Address: |
MCAFEE & TAFT
TENTH FLOOR, TWO LEADERSHIP SQUARE
211 NORTH ROBINSON
OKLAHOMA CITY
OK
73102
US
|
Family ID: |
28042346 |
Appl. No.: |
10/619671 |
Filed: |
July 14, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10619671 |
Jul 14, 2003 |
|
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09697855 |
Oct 27, 2000 |
|
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6623645 |
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Current U.S.
Class: |
210/691 |
Current CPC
Class: |
B01J 20/26 20130101;
B01J 20/267 20130101; B01J 2220/68 20130101; C02F 1/04 20130101;
C02F 1/285 20130101; F26B 9/10 20130101; C05G 3/80 20200201; F26B
2200/18 20130101; F26B 5/16 20130101; C02F 2101/16 20130101; C02F
2103/20 20130101; B01J 20/261 20130101 |
Class at
Publication: |
210/691 |
International
Class: |
C02F 001/28 |
Claims
What is claimed is:
1. A method for generating cool air, comprising: contacting a
wastewater with a superabsorbent polymer; allowing the
superabsorbent polymer and the wastewater to interact until
substantially all of the wastewater is absorbed by the
superabsorbent polymer; and evaporating the water from the
superabsorbent polymer.
2. The method of claim 1 wherein the evaporating step is performed
in the presence of a heat exchanger.
3. The method of claim 1 wherein the superabsorbent polymer is an
organic cross-linked acrylamide/acrylic acid copolymer.
4. The method of claim 1 wherein the superabsorbent polymer is
added to the wastewater in an amount of from about 2 grams to about
200 grams per liter of wastewater.
5. The method of claim 1 wherein evaporating the water is
facilitated by the use of a fan.
6. An apparatus for treating wastewater comprising: a floor; two
side walls connected to the floor; a top connected to the walls,
the top having perforations; a superabsorbent polymer positioned
above the top, the polymer having absorbed wastewater; an air
moving device for moving air through the perforations and across
the polymer such that water from the wastewater undergoes an
evaporation process.
7. The apparatus of claim 6 wherein the evaporation process has a
cooling effect.
8. The apparatus of claim 7 further comprising a first air
passageway for routing the air through the top.
9. The apparatus of claim 8 further comprising a second air
passageway for collecting cooled air.
10. The apparatus of claim 9 further comprising a plenum for
distributing cooled air.
11. The apparatus of claim 10 wherein the wastewater is produced by
an animal rearing facility.
12. The apparatus of claim 11 contiguous with the animal rearing
facility.
13. A method for generating cool air utilizing superabsorbent
polymers, comprising: providing a perforated top; placing a
superabsorbent polymer that has absorbed water in a space above the
top device; and forcing air through the top across the polymer such
that the absorbed water is evaporated.
14. The method of claim 13 further comprising collecting cool air
from a passageway adjacent the top.
15. The method of claim 13 wherein the superabsorbent polymer is an
organic cross-linked acrylamide/acrylic acid copolymer.
16. The method of claim 13 wherein the water is a wastewater.
17. The method of claim 16 wherein the wastewater is a wastewater
from an animal rearing facility.
Description
RELATED U.S. APPLICATION DATA
[0001] This Application is a divisional of co-pending Application
Serial No. 09/697,855 filed on Oct. 27, 2000.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates generally to methods and apparatus
for the containment and treatment of wastewater and particularly to
the use of superabsorbent polymers for the containment and
treatment of wastewater.
[0004] 2. Description of the Prior Art
[0005] Superabsorbent polymers (SAPs) are compounds capable of
absorbing water and swelling to many times their original size and
weight. SAPs generally absorb from about 100 to 1000 times their
weight in water and some SAPs absorb up to 1500 times their weight
in water. SAPs have many uses, e.g., as absorbing compounds in
diapers and incontinence products, for protecting power and
communication cables from moisture, in agriculture to increase the
capability of soil to retain moisture and nutrients, and in the
hygienic packaging of food products. SAPs are typically used alone
in granular or powder form or in a composite form in which SAP
particles are imbedded in pads or similar devices to enable easy
handling and convenient use.
[0006] In general, these SAPs are wide-mesh cross-linked,
water-insoluble polymers based on alkali metal salts of polyacrylic
acid or copolymers of alkali metal salts of acrylic acid and
acrylamide that are obtained by radical-initiated copolymerization
of acrylic acid and polyfunctional monomers such as divinylbenzene,
ethylene glycol dimethacrylate, ethylene glycol diallylether,
butanediol acrylate, hexanediol methacrylate, polyglycol
diacrylate, trimethylol propane diacrylate, allyl acrylate, diallyl
acrylamide, triallylamine, diallylether, methylene bis-acrylamide,
and N-methylol acrylamide. There are also SAPs based on
hydrolyzates of graft copolymers of acrylonitrile on starch and on
cross-linked starch/acrylic acid graft copolymers in which the
carboxyl groups are partly neutralized.
[0007] While there are various types of SAPs known in the art,
polyacrylic acid type SAPs are most often used for dewatering
operations. Polyacrylic acid type SAPs are polymers containing an
acrylic acid monomer unit of at least 50 mol % and are
substantially water-insoluble while being highly absorbent and
swellable for water. Such polyacrylic acid type SAPs include
polyacrylic acid cross-linked polymers or copolymers,
starch-acrylonitrile grafted polymer hydrolyzates, starch-acrylic
acid grafted cross-linked polymers, and vinyl acetate-acrylic ester
copolymer saponified products. In these polymers and copolymers, 60
to 90 mol % of the carboxyl groups thereof generally have their
hydrogen atom substituted with an alkali metal.
[0008] Many SAPs are well known in the art. For example, U.S. Pat.
No. 5,883,158 discloses a process for producing a SAP that absorbs
up to 1500 times its weight in water. U.S. Pat. Nos. 5,567,779 and
5,496,890 disclose acrylonitrile based SAPs that absorb up to 1000
times their weight in water. U.S. Pat. No. 5,453,323 discloses a
superabsorbent polymer having superior dryness that is made from
acrylic acid and a cross-linking agent polymerized under controlled
conditions. U.S. Pat. No. 5,451,613 discloses a carboxylic
containing superabsorbent polymer having improved absorption rates
and absorption under pressure. U.S. Pat. No. 5,684,106 discloses a
particulate superabsorbent polymeric material which is a partially
neutralized polymer of an ethylenically unsaturated carboxylic
monomer cross-linked by a triethylenic or higher ethylenic
cross-linking agent. Similarly, U.S. Pat. No. 4,511,477 discloses
cross-linked polymers containing polymerized acrylamide and sodium
2-acrylamide-2-methylpropane sulfonate and their use to remove
acidic water from fuels.
[0009] Wastewater is water containing dissolved and suspended
contaminants. Wastewater comes in many forms. Wastewater can be
sewage in the form of human or animal waste (human or non-human),
effluents from food processing and canning operations, runoff from
mining operations, radioactive wastes, hazardous wastes, or
industrial waste from manufacturing operations. Wastewater is used
herein to mean all such water based industrial and animal
wastes.
[0010] The disposal of wastewater is a major problem throughout the
world. Wastewater must be contained or controlled so that it does
not pollute aquatic habitats for plants and animals and does not
contaminate drinking water. In most instances, wastewater cannot be
disposed of until the contaminants have been reduced to a level
acceptable to governmental organizations, e.g., the Environmental
Protection Agency. For radioactive and other hazardous wastes,
there is no acceptable level for disposal. The wastewaters must be
contained and the contaminants removed before disposal.
[0011] Wastewaters from animal rearing and production facilities
are a major cause of air and water pollution. Ammonia is a common
cause of odor in animal rearing and production facilities,
particularly swine rearing facilities. The accumulation of manure
and urine in these wastewaters results in the production of ammonia
gas from ammonia volatilization and causes elevated levels of
ammonia gas in the atmosphere. Accumulation of ammonia gas causes
loss of production by the animals and causes respiratory problems
for the animals. Ammonia can also accumulate around wastewaters
from food processing and similar facilities.
[0012] Similarly, the disposal of wastewaters containing manure,
urine, milk, feed, and the like is of great concern. Nutrients and
other materials found in wastewaters containing animal waste
contaminate ground and surface waters and contribute to
eutrophication. Use of untreated agricultural wastewaters as
fertilizers has proven problematic because of biological
contaminants in the wastewaters. Also, the cost of transporting
untreated wastewaters is very high since most of the cost is
associated with transporting the water that makes up a large
portion, usually greater than 95%, of the waste. There exists,
therefore, a need for methods and apparatus to control the odor
caused by wastewaters and methods and apparatus for treating
wastewaters to manage the excess nutrients in many wastes,
particularly if the nutrients can be reused as a fertilizer.
[0013] The containment and treatment of wastewater is often a major
cost associated with a business enterprise. Much effort has been
devoted to developing methods and apparatus for containing and
treating wastewater in an economical way, e.g., using as little
energy as possible, reusing materials and energy if possible, and
minimizing the amount of solid waste. Despite this effort, however,
there exists a continuing need for new methods and apparatus for
economically and efficiently containing and treating wastewater and
for managing the byproducts of such treatment methods.
SUMMARY OF THE INVENTION
[0014] It is, therefore, an object of the invention to provide new
methods and apparatus for the containment and treatment of
wastewater.
[0015] It is another object of the invention to provide new methods
and apparatus for producing fertilizers and fertilizers produced by
such methods.
[0016] It is a further object of the invention to provide new
methods and apparatus for controlling odor caused by ammonia in
wastewaters.
[0017] It is another object of the invention to provide new methods
and apparatus for generating cool air utilizing the evaporation
process involved with treating wastewaters.
[0018] These and other objects are achieved by using superabsorbent
polymers (SAPs) for the containment and treatment of wastewaters.
The SAPs absorb substantially all of the wastewater and prevent it
from leaving a defined containment area. Once contained, the water
can be evaporated from the SAP to produce a substantially dry
polymer composition containing the SAP and the wastewater
contaminants. The dry polymer composition can be discarded or, when
appropriate, used as a fertilizer for plants and other vegetation.
Advantageously, the SAP reduces the odor associated with ammonia
containing wastewaters by binding to the ammonia and reducing the
ammonia gas present in the airspace around the wastewater. The
evaporation process may be conducted in the presence of a heat
exchanger to produce cool, fresh air that can be collected and used
to cool facilities, particularly animal rearing and production
facilities.
[0019] Other and further objects, features and advantages of the
present invention will be readily apparent to those skilled in the
art upon a reading of the description of preferred embodiments that
follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is a plan view of the apparatus of the present
invention.
[0021] FIG. 2 is a cross-sectional view at section 2-2 of the
apparatus illustrated in FIG. 1.
[0022] FIG. 3 is a cross-sectional view at section 3-3 of the
apparatus illustrated in FIG. 1.
DETAILED DESCRIPTION OF THE INVENTION
[0023] The present invention provides new methods and apparatus for
the containment and treatment of wastewaters. The methods for
contaminant of wastewater comprise contacting the wastewater with a
superabsorbent polymer (SAP) in a defined containment area and
allowing the SAP and the wastewater to interact until substantially
all of the wastewater is absorbed by the SAP. The SAP is contacted
with and allowed to absorb the wastewater before the wastewater
leaves the defined containment area. The containment methods,
therefore, prevent the wastewater from leaving the area where it
was generated and from entering adjacent aquifers and surface
waters.
[0024] The methods for treatment of wastewater comprise contacting
a wastewater with a SAP, allowing the SAP and the wastewater to
interact until substantially all of the wastewater is absorbed by
the SAP, evaporating the water from the SAP to produce a
substantially dry polymer composition containing the SAP and the
wastewater contaminants, and disposing of the substantially dry
polymer composition. The treatment methods, therefore, separate the
water from its contaminants and facilitate the individual disposal
or reuse of the water and the contaminants.
[0025] The SAPs useful in the present invention are those known in
the art. Useful SAPs include, but are not limited to, commercial
products sold under the trademarks and tradenames AmiSorb.RTM. and
Magnet.TM. available from the Donlar Corporation of 6502 South
Archer Road, Bedford Park, Ill. 60501, Stockosorb.RTM. Stockosorb
400K, Stockosorb Agro available from Stockhausen, Inc.,
Chem-Posites.TM. available from Emerging Technologies, Inc., 12-F
Wendy Court, Greensboro, N.C. 27409, Horta-Sorb.RTM. available from
Hotsorb, PO Box 5744, Sarasota, Fla. 34277, and Terra-Sorb.RTM.
available from Industrial Services International, Inc. Preferably,
the SAP is an organic cross-linked acrylamide/acrylic acid
copolymer based on potassium salt with water binding groups that
dissociate into negatively charged carboxyl ions which contain
large numbers of ionic groups that repel each other. Such preferred
SAPs are available commercially from known sources, e.g., Exacto,
Inc., 7617 State Route 31, Richmond, Ill. 60071, under the
trademark SORBEX.RTM. superabsorbent polymer.
[0026] The SAPs are interacted with the wastewater in an amount
sufficient to absorb substantially all of the wastewater. The
amount of SAP needed to absorb substantially all of the wastewater
depends somewhat upon the source of the wastewater and the
contaminants therein. Generally, the SAP is contacted with the
wastewater in an amount of from about 2 to about 200 grams of SAP
per liter of wastewater, preferably from about 10 to about 100
grams of SAP per liter of wastewater.
[0027] The wastewater contained or treated according to the present
invention can be any wastewater from industrial or animal wastes.
Human and other animal sewage can be contained and treated by the
methods of the present invention, particularly those from swine,
dairy, and poultry operations. Similarly, swine runoff containing
dissolved solids and other contaminants, slaughterhouse effluents,
tanning process effluents, food processing, canning, and the like
can be treated using these methods. Radioactive and hazardous
wastewaters produced during the generation of radioactive and other
materials for use by industry can also be treated by the above
methods. Also, wastewater spills and their containment and
treatment are encompassed by the methods of the present invention.
For example, the spill of an aqueous solution containing a
pesticide can be contained by contacting the spill with SAPs and
allowing the SAP to absorb the solution. The spill can be treated
by removing the SAP containing the solution from the spill site and
evaporating the water to produce a substantially dry polymer
composition containing the SAP and the pesticide. The polymer
composition can then be disposed of by techniques appropriate for
the pesticide. Preferably, the wastewater is selected from the
group consisting of wastewaters from confined animal feeding
operations and food processing operations.
[0028] Wastewaters can also be generated by passing air around or
through contaminated solids or liquids such that the air becomes
contaminated with undesirable waste gases. The contaminated air is
then passed through water where the contaminants dissolve in the
water to produce a wastewater that can be treated with the SAPs of
the present invention. In one embodiment, air is passed through an
enclosed animal rearing facility where the ammonia gas generated by
animal wastes becomes mixed with the air. The contaminated air is
bubbled through water where the ammonia dissolves in the water to
produce a wastewater ammonia solution. The resulting ammonia
solution is contacted with SAPs to absorb the ammonia solution and
the SAP is treated according to the methods described herein. In a
particularly preferred embodiment, the SAPs are in the water when
the air containing ammonia is bubbled through the water.
[0029] The SAPs are contacted with the wastewater by any convenient
means. The SAPs can be added to standing wastewaters in granular or
powder form or the SAPs can be added to a collection tank and the
wastewaters allowed to run or trickle into the tank and contact the
SAPs as the wastewater is generated. The SAPs can be spread on the
floor or subfloor of a worksite or in an animal's cage and allowed
to contact the wastewater as it is generated. For spills, the SAPs
can be spread onto the spill and allowed to absorb the spilled
wastewater.
[0030] In one embodiment, wastewaters that may contain bacteria,
virus, protozoa, yeasts, fungi, or other biological agents, e.g.,
wastewaters generated in animal and food processing operations, are
separated from the SAP by a selective membrane that allows water
molecules and other relatively small wastewater components to pass
through the membrane and interact with the SAP but does not allow
the biological agents to pass through the membrane and interact
with the SAP. By eliminating the biological agents from the SAP,
the SAP's useful life is extended and the SAP can be disposed of
without treatment to reduce or eliminate the potentially harmful
biological agents. Membranes useful in this method include any
membrane known to have a pore size that will retain the biological
agents while allowing water to pass through the membrane.
[0031] Upon contact, the SAP and wastewater are allowed to interact
until the wastewater and its contaminants are absorbed by the SAP
and produce a gel that can be dewatered through evaporation to
produce a substantially dry polymer composition containing the SAP
and the wastewater contaminants. While it is desirable to remove
all of the water through evaporation, the SAPs of the present
invention are substantially dry when about 75% or more of the water
has been removed. Preferably, about 90% of the water is
removed.
[0032] The water canbe evaporated by any convenient means.
Preferably the gel is exposed to an air-flow that facilitates the
evaporation of the water. Such air-flow can be from a natural
source such as convection or the wind or can be artificially
produced by fans or similar apparatus. Heat can be added to the
system to facilitate evaporation if required but is not preferred
because of the cost.
[0033] The substantially dry polymer composition containing the SAP
and the wastewater contaminants produced by the evaporation process
can be disposed of by discarding the dry polymer composition, e.g.,
by incineration or in a landfill, or can be reused by again
contacting the substantially dry polymer composition with
wastewater. However, at some point when the polymer composition has
collected sufficient contaminants and is no longer efficient at
absorbing the wastewater, the determination of which is well within
the skill of the artisan, the polymer composition cannot be reused
and must be discarded.
[0034] When the contaminants in the polymer composition have no
beneficial use, the polymer composition is disposed of by
discarding it as described herein. However, when the contaminants
have a beneficial use, the polymer composition may be disposed of
by using it for a beneficial purpose. For example, when the
wastewater contains sewage or other elements useful as a
fertilizer, the dry polymer composition can be processed and spread
on soil as a fertilizer to promote plant growth. The present
invention, therefore, provides a method for producing a fertilizer
and a fertilizer useful for promoting plant growth. The method for
producing the fertilizer comprises contacting a wastewater
containing contaminants useful as a fertilizer with a SAP, allowing
the SAP and the wastewater to interact until most or substantially
all of the wastewater is absorbed by the SAP, evaporating the water
from the SAP to produce a substantially dry polymer composition
containing the SAP and the wastewater contaminants useful as a
fertilizer, and disposing of the substantially dry polymer by
applying the dry polymer as a fertilizer.
[0035] Generally, the dry polymer composition is separated from
other contaminants by meshes or sieves, treated to destroy any
unwanted biological agents, and transported to farmlands for use as
a fertilizer. The polymer composition could, however, be bagged and
sold for use in greenhouses or other botanical applications. The
type of fertilizer produced and type of plant that can use the
fertilizer will depend upon the source and content of the
wastewater. For example, when the wastewater is from a swine,
dairy, or poultry production facility, the polymer composition is
useful as a fertilizer for pastures. Alternatively, the polymer
composition could be blended with other fertilizers to produce a
desirable fertilizer mixture useful in almost any application.
[0036] In a preferred embodiment, SORBEX.RTM. 9001-XGL
superabsorbent polymer is mixed with wastewater known to contain
animal wastes, preferably from a swine production facility, at an
amount of 50 grams of SAP per liter of wastewater. The SAP absorbs
substantially all of the wastewater and produces a gel containing
the wastewater. The gel is transported to an evaporation platform
where it is spread to allow air to flow easily about the gel. The
water in the gel is evaporated by the use of fans to circulate air
about the gel and evaporate the water. The substantially dry SAP
containing the contaminants is collected and contacted with another
batch of wastewater and the cycle is repeated. If the substantially
dry SAP contains excess contaminants, it is disposed of according
to methods of the present invention and new SAP is used in the
process.
[0037] The present invention also provides new methods for
controlling the odor caused by ammonia in wastewaters.
Surprisingly, it has been discovered that SAP exposed to
wastewaters that contain ammonia will reduce the amount of ammonia
in the airspace surrounding the wastewater. The methods of the
present invention for controlling odor caused by ammonia in
wastewaters comprise contacting the wastewater with a SAP and
allowing the SAP and the wastewater to interact until a substantial
portion of the ammonia gas in the wastewater and in the airspace
surrounding the wastewater is physically or chemically bound to the
SAP. This reduces the amount of ammonia gas in the airspace around
the wastewater and reduces the odor caused by the ammonia gas.
[0038] The SAP is added in sufficient quantities to bind to the
ammonia but not to completely absorb the wastewater. Generally, the
SAP is added to the wastewater in amounts of from about 1 gram to
about 30 grams of SAP per liter of wastewater. The SAPs have been
found to bind to and remove up to 60% of the total ammonia gas from
the airspace surrounding the wastewater, particularly when the
airspace is enclosed and the ammonia gas cannot escape to the
atmosphere.
[0039] In a preferred embodiment, wastewater from a swine rearing
facility is mixed with SAP in an amount of from about 10 grams of
SAP per liter of wastewater. The SAP binds to the ammonia in the
wastewater and reduces the ammonia gas in the airspace around the
wastewater by up to about 40%. This significantly reduces air
pollution, reduces the odor encountered by the animals and the
human caretakers and increases the habitability of the facility for
the animals and the caretakers.
[0040] The present invention also provides new methods for
generating cool air utilizing the evaporation process involved with
treating wastewaters according to the present invention. The method
comprises evaporating the water from the gels produced by the
absorption of wastewaters by SAPs. The evaporation process provides
a cooling effect. In a preferred embodiment, wastewaters generated
by animal rearing facilities, particularly swine rearing
facilities, are absorbed by SAPs to produce gels containing the
wastewater. The water in the gels is evaporated in the presence of
a heat exchanger. The evaporation process cools the air in the heat
exchanger and the cool air is circulated throughout the animal
rearing facility. This process provides cool, fresh air to the
animals and cools the facility.
[0041] The present invention also provides a new apparatus for
generating cool air when evaporating the water from SAPs according
to the present invention. The apparatus is shown in FIGS. 1-3 and
generally referred to by the numeral 10. Referring to FIGS. 1-3,
the apparatus 10 has a floor 11 with two side walls 12 connected to
floor 11. Apparatus 10 has a top 14 connected to walls 12 and
positioned above and generally parallel to floor 11. Top 14 is
perforated such as by a plurality of holes 16 that allow air to
pass through the top. The device also has a plurality of ridges 18
attached to and extending perpendicular from floor 11 above the
top. Ridges 18 extending above top 14 form a space 19 that can
contain materials, e.g., a SAP 21 that has absorbed wastewater.
Apparatus 10 has a plurality of plates 20 angularly disposed
between walls 12 and floor 11 and between ridges 18 and floor 11.
The ridges 18, plates 20, and top 14 form a first air passageway 22
and the ridges 18, plates 20, and floor 11 form a second air
passageway 24 that permits air to enter and exit apparatus 10.
Apparatus 10 contains an end plate 26 on the exit end 28 of
apparatus 10 that sealably covers the end of first air passageway
22. End plate 26 prevents air from escaping through exit end 28 and
forces air entering first passageway 22 through the entry end 30 to
exit through holes 16 in top 14. Apparatus 10 has a cool air plenum
32 on exit end 28 that is sealably connected to second air
passageway 24. Plenum 32 is connected such that air entering second
air passageway 24 through entry end 30 must exit apparatus 10
through plenum 32 where it can be collected and routed as
desired.
[0042] In operation, the SAP 21 that has been used to collect
wastewater according to the present invention is placed in space 19
formed by ridges 18 above top 14 such that the SAP 21 covers holes
16 in top 14. Holes 16 are sized to prevent the SAP 21 from passing
through holes 16 and into first air passageway 22. Air is forced
through first and second air passageways 22, 24 through entry end
30 using a fan 34 or other air moving device. The air in first air
passageway 22 must exit through holes 16 in top 14 because end
plate 26 prevents the air from exiting through exit end 28. The air
exiting through holes 16 contacts the SAP 21 in space 19 and
evaporates the water from the SAP 21. The process of evaporation
cools apparatus 10 in general and, in particular, cools ridges 18
and plates 20. Air passing through second air passageway 24 is
cooled by the now cool ridges 18 and plates 20. Cooling fins and
similar devices (not shown) may also be added to second air
passageway 24 to improve cooling efficiency. The cool air exits
second air passageway 24 and enters plenum 32 at the exit end 28 of
apparatus 10. The cool air can be collected and routed as desired.
The ridges 18, plates 20, and top 14 should be constructed of a
material that is a good conductor of heat, e.g., aluminum, such
other materials being known to the skilled artisan.
[0043] In another aspect, the present invention provides a method
for generating cool air using the device of the present invention
and a SAP that has been used to absorb water, preferably
wastewater. The method comprises placing a SAP that has absorbed
water in the space formed by the ridges above the top of the
device, forcing air through the device, and collecting cool air
from the second passageway in the plenum.
[0044] Apparatus 10 may be easily adapted to the specific
wastewater treatment application. For example, in the application
of treating animal waste, a livestock containment facility can be
constructed using apparatus 10. In this application, animal waste
is secreted directly or indirectly into the SAP 21. Fan 34
periodically or continuously moves air through first air passageway
22 and through holes 16 in top 14 to keep the wastewater
contaminant substantially dry and extend the useful life of the SAP
21. The air moving across the SAP 21 is cooled which in turn cools
the area above the SAP 21, i.e., the livestock containment
facility. This evaporation process, which results in cool air in
second passageway 24 collected at plenum 32, can be also circulated
into the livestock containment facility for additional cooling
effect or into a completely different facility. Similar adaptations
of apparatus 10 to the specific wastewater treatment applications
described herein are readily apparent to one skilled in the
art.
[0045] In order to further illustrate the methods and compositions
of the present invention, the following examples are given.
EXAMPLE 1
Initial Screening for Ammonia Absorption Using SORBEX.TM.
9001-XLG
[0046] An initial screening test was conducted using household
ammonia solutions of various strength dilutions and household
ammonia solutions treated with the SAP SORBEX.TM. 9001-5 XLG.
Solutions were made from household ammonia (14% strength) and
diluted to 10% and 1% of original strength with distilled water.
Approximately 1 gram of SAP and 50 ml of the solution to be tested
were placed in a 500 ml glass jar and sealed with Saran Wrap.TM..
The system was allowed to equilibrate for 4 hours. The equilibrated
systems were analyzed for the presence of ammonia by having three
panel members, designated A, B and C, sniff the system and score
for the odor of ammonia. The scores were: 0=absent, 1=weak
presence, and 2=strong odor detected. The entire experiment was
replicated and the replications totaled. The results are shown in
Table 1.
1TABLE 1 Rating by Panel Total Score Solution Replication 1
Replication 2 (6 total Strength Treatment A B C A B C observations)
Distilled Water None 0 0 0 0 0 0 0 Distilled Water +1 gm SAP 0 0 0
0 0 0 0 0.14% None 1 1 1 1 1 1 6 0.14% +1 gm SAP 0 0 0 0 0 0 0 1.4%
None 2 2 1 2 2 2 11 1.4% +1 gm SAP 1 1 2 2 1 2 9
[0047] Referring to Table 1, the results show that ammonia was not
detected by sniffing headspace air when the solutions contained
less than 1.4% ammonia. Therefore, SAPs are effective for absorbing
ammonia from ammonia containing solutions.
EXAMPLE 2
Waste Treatment from Swine Production
[0048] Groups of swine (six littermates) with an initial weight of
30 to 35 pounds each were placed in pairs in open cages with
self-feed and water. The cages had false floors (wire mesh) which
allowed the urine and feces to pass through to a large pan just
below. In the first pan, water was added (and the level maintained
during the week compensating for evaporation) to mix with the swine
wastes according to standard methods of rearing feeder pigs in
commercial operations. In the pan below the second cage, 100 grams
of SORBEX.TM. 9001-XLG was added and adjusted to leave free water
initially (level also maintained). Under the third cage, 300 grams
of SORBEX.TM. 9001-XLG was spread on the pan floor with no water,
with the urine swelling the SAP during the trial.
[0049] At the end of one week, the cages were totally enclosed
under tarpaulin covers, and intake hoses for one of three identical
aquarium air pumps placed in the upper portion of each cage which
was allowed to set for a twelve hour period. The pumps were then
activated for 12 hours, discharging into one liter of distilled
water. The resulting solutions were analyzed for ammonia content.
The unexposed distilled water source was included in the samples
along with unexposed water from the trial site.
[0050] The wastewater from pans 1 and 2 were diluted 10:1 and
sampled for ammonia. Each measurement was completed using EPA
method 330.3. The results are shown in Table 2.
[0051] Afterwards, the SAP/waste mixtures were allowed to dry in
air on screen wire tables and observed over several cycles of
drying and rehydration. The SAP became discolored after several
cycles to a dark amber color. This discoloration, however, did not
significantly effect the SAPs ability to absorb water.
2TABLE 2 Concentration Sample Source Treatment Head Space Air
Solution Wastewater From Pan 1) First Cage 15.50 mg/L 198 mg/L 2)
Second Cage 8.92 mg/L 166 mg/L 3) Third Cage 3.74 mg/L * 4)
Distilled Water 0.05 mg/L 5) Water From Site 0.22 mg/L *No valid
test could be made on the sample source from the Third Cage because
the SAP/waste was totally absorbed
[0052] Referring to Table 2, the results show that the ammonia in
the headspace air was correlated to the ammonia in the solution,
that the waste stream could be fully absorbed by the SAP, and that
the SAP gel maintained its ability to shrink and swell with wet/dry
cycles, even though the SAP was colored in the process to various
shades of brown. Therefore, SAPs such as SORBEX.TM. 9001-XGL can be
used to contain, treat, and abate swine waste streams.
EXAMPLE 3
Ammonia Absorbing Capacity of SAPs
[0053] 400 milliliters of a 1.4% ammonia solution was added to
either zero or 3 grams of SORBEX.TM. 9001-XLG. The solutions were
allowed to stand in closed containers for 1 hour.
[0054] The supernatant was then removed to another closed
container. The supernatant was tested using standard EPA electrode
testing procedures to determine the amount of NH.sub.3 and
potassium present in the supernatant. Potassium was measured to
determine if the ammonia was being physically or chemically bound
to the SAP, an increase in potassium in solution indicating
chemical binding because SORBEX.TM. 9001-XLG is a K salt SAP.
Potassium is bound to the SAP and an increase in potassium
concentration in solution indicates that potassium has been
replaced by ammonia in the SAP structure. The results are shown in
Table 3.
3 TABLE 3 Ammonia Potassium (mg) (mg) EPA Method 400 ml of 1.4%
solution 1070 0.078 350.2 400 ml of 1.4% solution 910 0.290 200.7
containing 3 grams of SAP
EXAMPLE 4
Headspace Ammonia Determination
[0055] Deuterium was substituted for hydrogen in NH.sub.4 and
H.sub.2O in various ammonia concentrations. The headspace levels of
ammonia were determined with a mass spectrometer that could
adequately separate these greater weights. Seven vials with the
following concentrations of ammonia were created: 0, 0.7, 1.4, 2.8,
7.0, 14 and 28%. 200 milligrams of SORBEX.TM. 9001-XLG were added
to the vials. As shown in Table 4, the appropriate amount of
D.sub.2O and ND.sub.4OD was added to the vial to produce a solution
with a final volume of 10 milliliters.
4 TABLE 4 Conc. (%) SAP (mg) ND.sub.4OD (ml) D.sub.2O (ml) 0 200 0
10.0 0.7 200 0.25 9.75 1.4 200 0.5 9.5 2.8 200 1.0 9.0 7 200 2.5
7.5 14 200 5.0 5.0 28 200 10.0 0
[0056] The solutions were allowed to equilibrate for 2 hours and
then analyzed for ammonia by headspace GC/MS. The results are shown
in Table 5.
5TABLE 5 Conc. % MS* abundance Ammonia level Ammonia Present (+/-)
0 630 0 - 0.7 770 140 - 1.4 753 123 - 2.8 731 101 - 7 3162 2530 +
14 11547 10917 + 28 26630 26000 + *MS--Mass spectrometer
[0057] Referring to Table 5, the results show that the threshold
for headspace "ammonia" was between 2.8 and 7.0% after long-term
equilibration (over 24 hours).
[0058] While the preferred embodiments are shown to illustrate the
invention, numerous changes to the materials and methods can be
made by those skilled in the art. All such changes are encompassed
within the spirit of the invention as defined by the appended
claims.
* * * * *