U.S. patent application number 10/146966 was filed with the patent office on 2003-11-20 for alum pellets.
This patent application is currently assigned to Halliburton Energy Services, Inc.. Invention is credited to Harvey, Robert A., Landis, Charles R., Oaks, Danny, Rothermel, Ricky P..
Application Number | 20030213752 10/146966 |
Document ID | / |
Family ID | 29418923 |
Filed Date | 2003-11-20 |
United States Patent
Application |
20030213752 |
Kind Code |
A1 |
Landis, Charles R. ; et
al. |
November 20, 2003 |
Alum pellets
Abstract
Compositions including pellets of alum, a smectite mineral
material and optionally sodium or calcium carbonate that can be
delivered to a phosphate impoundment located at the bottom of a
body of water at the bottom. The pellets of alum, smectite mineral
material and optionally sodium or calcium carbonate are dropped
through the body of water so that the alum is released when the
pellet reaches the bottom of the impoundment thereby treating the
phosphates.
Inventors: |
Landis, Charles R.;
(Littleton, CO) ; Oaks, Danny; (Cowley, WY)
; Rothermel, Ricky P.; (Belle Fourche, SD) ;
Harvey, Robert A.; (Lovell, WY) |
Correspondence
Address: |
CRAIG W. RODDY
HALLIBURTON ENERGY SERVICES
P.O. BOX 1431
DUNCAN
OK
73536-0440
US
|
Assignee: |
Halliburton Energy Services,
Inc.
Duncan
OK
|
Family ID: |
29418923 |
Appl. No.: |
10/146966 |
Filed: |
May 16, 2002 |
Current U.S.
Class: |
210/723 |
Current CPC
Class: |
Y10S 210/906 20130101;
C02F 2305/14 20130101; C02F 1/505 20130101; C02F 1/5236 20130101;
C02F 2101/105 20130101; B01J 20/3204 20130101 |
Class at
Publication: |
210/723 |
International
Class: |
C02F 001/52 |
Claims
What is claimed is:
1. A method of treating a phosphate impoundment in a body of water
comprising: adding to the body of water a composition comprising
alum and a smectite mineral material, wherein the composition is in
a form selected from a tablet, extruded noodle, pellet, briquette
or ribbon; and releasing alum from the composition as the
composition passes through the body of water.
2. A method according to claim 1, wherein the smectite mineral
material is selected from the group consisting of: bentonite,
attapulgite, saponite, hectorite, sepiolite and fallers earth.
3. A method according to claim 1, wherein the composition retains
about 90 percent of the integrity of its form for about 2
minutes.
4. A method according to claim 1, wherein the composition further
comprises a pH buffer selected from the group consisting of sodium
carbonate and calcium carbonate.
5. A method according to claim 1, wherein the composition
comprising alum and smectite material is coated with a water
soluble resin material selected from corn starch, guar gum,
alginates, polyvinyl alcohol and partially hydrolyzed
polyacrylamides.
6. A method according to claim 5, wherein the composition retains
about 90 percent of the integrity of its form for about 24
hours.
7. A method according to claim 1, wherein the composition in the
form of a tablet, extruded noodle, pellet, briquette or ribbon, has
a diameter of from 1/4 to 24 inches.
8. A method according to claim 1, wherein the composition in the
form of a tablet, extruded noodle, pellet, briquette or ribbon, has
a density of from 1.0 to 2.0 gm/cm.sup.3.
9. A method of treating a phosphate impoundment in a body of water
comprising: adding to the body of water a composition comprising
alum and a smectite mineral material, wherein the composition is in
a form selected from a tablet, extruded noodle, pellet, briquette
or ribbon; and delivering the composition to the sediment water
interface whereby alum is released from the composition at the
sediment water interface.
10. A method according to claim 9, wherein the smectite mineral
material is selected from the group consisting of: bentonite,
attapulgite, saponite, hectorite, sepiolite and fullers earth.
11. A method according to claim 9, wherein the composition retains
about 90 percent of the integrity of its form for about 2
minutes.
12. A method according to claim 9, wherein the composition further
comprises a pH buffer selected from the group consisting of sodium
carbonate and calcium carbonate.
13. A method according to claim 9, wherein the composition
comprising alum and smectite material is coated with a water
soluble resin material selected from corn starch, guar gum,
alginates, polyvinyl alcohol and partially hydrolyzed
polyacrylamides.
14. A composition for treating a phosphate impoundment in a body of
water comprising: a) alum; and b) a smectite mineral material.
15. A composition according to claim 14, wherein the smectite
mineral material is selected from the group consisting of:
bentonite, attapulgite, saponite, hectorite, sepiolite and fullers
earth.
16. A composition according to claim 14, further comprising a pH
buffer selected from the group consisting of: sodium carbonate and
calcium carbonate.
17. A composition according to claim 14, further comprising a water
soluble resin material selected from guar gum, alginates, polyvinyl
alcohol and partially hydrolyzed polyacrylamides.
18. A composition according to claim 14, where the composition
comprises from 30 to 99 percent by weight of alum and from 1 to 70
percent by weight of the smectite mineral material.
19. A composition according to claim 16, wherein the composition
further comprises from 0 to 30 percent by weight of the pH
buffer.
20. A composition according to claim 17, wherein the composition
further comprises from 0 to 5 percent by weight of the water
soluble resin.
Description
BACKGROUND
[0001] The present embodiment relates generally to the production
of pellets of alum, a smectite mineral-bearing industrial material
such as bentonite (montmorillonite), attapulgite, saponite,
hectorite, sepiolite and fullers earth and optionally sodium or
calcium carbonate that can be delivered to concentrated or
impounded phosphate located at the bottom of various bodies of
water. More particularly, the pellets of alum, a smectite mineral
material as described above and optionally sodium or calcium
carbonate can be delivered to a wider range of locations in bodies
of water including to sites known as the "sediment water interface"
which is an area that can be generally defined as the top six
inches of sediment combined with the deepest six inches of water.
Even more particularly, the pellets of alum, a smectite mineral
material as described above and optionally sodium or calcium
carbonate are dropped through the body of water so that the alum is
released when the pellet reaches the desired location in the water,
thereby treating the phosphates more efficiently and using or
consuming less alum.
[0002] Acidic metal salt and sulfate solutions, such as aluminum
sulfate ((Al.sub.2SO.sub.4).sub.3.14H.sub.2O) solutions, commonly
known and referred to as "alum," have long been used to remove
color and suspended particles, as well as organic and
microbiological contaminants from water. Alum is readily available
and when diluted with surface water, it can function as a
coagulant, flocculent, precipitant and emulsion breaker. As a
coagulant, alum removes the primary nutrient for blue-green algae
in the water. This function is important because these algae remove
oxygen from the water (known as biochemical oxygen demand or BOD)
and thus pose a danger to fish. Alum also forms an insoluble
precipitate or floccule, i.e., a floc, with the impurities in the
water. The floc grows in size as it attracts suspended and
colloidal particles and organic compounds present in the water. The
floc settles out of the water over time and can be removed by well
known techniques such as by decanting or filtration.
[0003] One of the most difficult problems in water pollution
control is the growth of algae. As noted above, algal organisms
exert a BOD on the water and the algal BOD can often exceed the
oxygen resources of the water. Algal growths can also cause
unpleasant tastes and odors in water supplies. Dissolved phosphate
ions provide algae with a necessary nutrient supply. If the
phosphate supply could be removed the algae would not survive or
flourish in the water column and a water pollution control problem
would be addressed. An additional difficulty associated with the
treatment of phosphates in water is that the majority of the
phosphates (50-90%) are concentrated at the sediment-water
interface of an impoundment and current application techniques
involving alum primarily treat the phosphates closer to the surface
of the body of water. In addition, current techniques have been
focused on nearly instantaneous sorption of phosphates. As a
result, the body of existing products and techniques do not perform
as effectively in a number of water systems, especially high energy
and deep systems, and in systems that require more than just
instantaneous phosphate sorption. In the former case, alum is
flushed from the target waters before it can perform. In the latter
case, the alum is poorly utilized in application. Also, the alum
can leave an unwanted white cloud in the water for an extended
period of time.
[0004] Therefore, there is a need for simple compositions, forms
and methods for treating phosphate impoundments in bodies of
water.
DETAILED DESCRIPTION
[0005] According to one embodiment, a phosphate impoundment is
treated with a composition that includes alum and a member of the
smectite family of minerals as the two major components. As used
herein the term "alum" shall be used to refer to aluminum sulfate
((Al.sub.2SO.sub.4).sub.3.14H.- sub.2O). Among the smectite bearing
ores, or industrial minerals, is bentonite. Bentonite is the ore
enriched in the smectite called montmorillonite. As used herein the
term "smectite mineral material" shall be used to refer to
bentonite, attapulgite, saponite, hectorite, sepiolite and fullers
earth. This embodiment also optionally includes sodium carbonate or
calcium carbonate. According to a second embodiment, the alum and
smectite mineral material preferably are covered or coated by
techniques well known to those skilled in the art, with one or more
natural organic by-products such as corn starch, sugar-based
resins, and various natural product derivatives such as chemical
families of resins and starches. Suitable resins and coatings
include guar gum, alginates, polyvinyl alcohol, partially
hydrolyzed polyacrylamides and other similar polymers well known to
those skilled in the art.
[0006] The compositions of these embodiments selectively remove
phosphates from natural and man-made water systems. Phosphates are
a primary nutrient for aquatic flora/fauna such as blue-green algae
which produce unsightly green slimes and clouds, and undesirable
odors in waters. By removing the phosphates, the algae are deprived
of nourishment and therefore do not proliferate in the water
column.
[0007] Each component of the compositions of the present
embodiment, serves a function in the product towards the goal of
optimal sorption and thus removal of phosphates. Alum is a water
treatment product that is used to remove phosphates and other
compounds such as dissolved organics, suspended sediment, and
metals from a body of water. The primary purpose of the alum is to
sorb the phosphates from the water or sediments. Alum is generally
commercially available from General Chemical Corporation.
[0008] The smectite mineral material, preferably, bentonite
functions to 1) optimize the timing of the dissolution of the
composition in the water column, 2) buffer the pH of the water that
is being treated to a neutral pH level, and 3) optimize or control
the density of the composition to more precisely estimate the
residence time in the water column. Bentonite is generally
commercially available from Bentonite Performance Minerals.
[0009] Compositions of uncoated alum and smectite mineral material
generally retain approximately 90% of their integrity or shape for
up to approximately 2 minutes. Compositions of alum and smectite
mineral material that have been coated with accessory additives
such as water soluble resins, natural polymers and macromolecular
by-products from grain and agriculture industries dissolve in water
at a much slower rate than uncoated compositions. Specifically, the
coated compositions generally retain approximately 90% of their
integrity or shape for up to approximately 24 hours. The
concentration of the accessory additives preferably is less than
five percent by weight of the total composition.
[0010] According to another embodiment, the compositions preferably
include a pH buffering agent selected from sodium carbonate
(Na.sub.2CO.sub.3) or calcium carbonate (Ca.sub.2CO.sub.3). In
addition to buffering the pH of the body of water, the pH buffering
agent also enhances the density of the composition for use in
higher energy--higher flow--water systems.
[0011] According to a preferred embodiment, the composition
includes from 30-99% by weight of alum and from 1-70% of a smectite
mineral material. According to another preferred embodiment, the
composition further includes from 0-5% natural water soluble resins
and byproducts as a coating. According to still another preferred
embodiment, the composition further includes from 0-30% of a pH
buffering agent selected from sodium carbonate and calcium
carbonate.
[0012] The compositions of the present embodiment are manufactured
and produced according to techniques well known to those skilled in
the art. Preferably, the compositions of the present embodiment are
produced in the form of spheres to oblate spheroids, cylinders to
cubes and three-dimensional rectangles ranging in size from 1/4" to
24" in diameter. More preferably, the compositions of the present
embodiment are produced in the form of tablets, pellets, extruded
noodles, briquettes or ribbons by equipment well known to those
skilled in the art such as extruders, tabletizers, briquetters or
agglomerators. In the process of forming such tablets, extruded
noodles, briquettes or ribbons, each component of the compositions
are provided in powdered or granular form and the components are
blended. Preferably, the raw material components are blended in the
proportions noted above and are physically mixed at the desired
levels in tanks or similar units of 20 to 200 ton capacity, by
augers and paddles for a prescribed amount of time, preferably from
5 minutes to up to 6 hours in batch mode, or by continuous metered
feed onto a common belt or in a common continuously producing
extruder, pelletizer, tabletizer, or agglomerator. For instance, a
typical extruder is in the form of an elongated rectangular tub
with at least one and optionally two augers oriented parallel to
the ground that physically mixes the materials into a uniform
mixture of the composition and then passes the composition through
a restricted opening to form elongated noodles or cylindrical
pellets. Conventional tabletizers and pelletizers take the mixed
materials from a storage tank and compress the mixture via
converging die plates into forms in the order of 1/4 to 1" diameter
spheres and spheroids. Commercial agglomerators take the mixtures
as a powder (having a particle size ranging from 44 .mu.m to 100
.mu.m) and non-compressively combines the mixture into spheroids.
Preferably, the composition has a moisture content of from 1 to 15
percent by weight. Preferably, the compositions manufactured
according to the above mentioned processes may be coated with
accessory additives such as water soluble resins, natural polymers
and macromolecular by-products from grain and agriculture
industries according to techniques well known to those skilled in
the art. Those skilled in the art will also recognize that other
well known techniques may also be utilized to manufacture the
compositions of the present embodiment.
[0013] The composition of the present embodiment has utility in the
following water treatment markets: municipal water treatment
polishing agent, commercial construction/engineering, agricultural
feedstock (such as in piggeries, cattle, sheep and ostrich farms),
aquaculture (fish farms and hatcheries, such as for shrimp, salmon
and trout), natural lake and river systems and watersheds,
recreational and leisure (golf course ponds, amusement parks and
aquatic centers), industrial effluent management, and mining and
exploration (tailings ponds and discharge systems).
[0014] The composition of the present embodiment, is a time release
alum-based sorbent of phosphates in water. The vast majority of
phosphate-laden water systems contain a minority of suspended or
dissolved phosphates in the water column as compared to the
sediment water interface. As used herein, the term "sediment water
interface" shall be used to refer to an area in a body of water
that is generally defined as the top six inches of sediment
combined with the deepest six inches of water. In the vast majority
of water systems such as lakes, rivers, ponds or trenches, the
majority of the total phosphates is located at the sediment water
interface. Powdered alum tends to remain in suspension removing the
suspended phosphates, organic matter, and other sediment but rarely
reaches the targeted problem area in need of such treatment.
Preferably the density of individual tablets of the composition of
the present embodiment ranges from 1.0 to 2.0 gm/cm.sup.3. It is
also preferred that the individual pellets of the composition of
the present embodiment have a diameter that ranges from 1/4" to
24". Most preferably, the composition of the present embodiment has
a density and size such that the compositions settle quickly
through the water column arriving where they are needed most at the
sediment water interface.
[0015] The calculation for settling in water systems is based upon
the long accepted Stokes Settling Law which describes the rate of
settling of a particle based upon the density of the particle and
the density of the water. This law is a proven scientific principle
used in a number of industries and can be used to estimate settling
distances and time parameters for the composition of the present
embodiment. As noted above, the uncoated composition according to
the present embodiment will retain approximately 90% of its
particle integrity for about 2 minutes which translates to a
minimum of 50 feet of water column at the percentages of alum and
smectite mineral material indicated above.
[0016] In commercial terms, the average depth of the water columns
needing to be cleaned up will be about 6', so according to Stokes
Law, the uncoated product will reach the sediment water interface
well in advance of the onset of significant dissolution.
Variations and Equivalents
[0017] Although only a few exemplary embodiments have been
described in detail above, those skilled in the art will readily
appreciate that many other modifications are possible in the
exemplary embodiments without materially departing from the novel
teachings and advantages described herein. Accordingly, all such
modifications are intended to be included within the scope of the
following claims.
* * * * *