U.S. patent application number 12/907773 was filed with the patent office on 2011-04-21 for soil stabilization system.
This patent application is currently assigned to TerraFusion, Inc.. Invention is credited to Leigh L. Lindenbaum.
Application Number | 20110091275 12/907773 |
Document ID | / |
Family ID | 38163563 |
Filed Date | 2011-04-21 |
United States Patent
Application |
20110091275 |
Kind Code |
A1 |
Lindenbaum; Leigh L. |
April 21, 2011 |
SOIL STABILIZATION SYSTEM
Abstract
A construction article including a compacted mixture that
includes soil and a crop plant biomass microorganism-expressed
enzyme composition. A method of stabilizing soil including: (i)
mixing together soil, water and a crop plant biomass
microorganism-expressed enzyme composition to form a mixture; (ii)
causing the mixture to be shaped into a selected structure; and
(iii) causing the structure to be compacted.
Inventors: |
Lindenbaum; Leigh L.; (New
York, NY) |
Assignee: |
TerraFusion, Inc.
New York
NY
|
Family ID: |
38163563 |
Appl. No.: |
12/907773 |
Filed: |
October 19, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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12097345 |
Jun 13, 2008 |
7841806 |
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PCT/US06/48094 |
Dec 15, 2006 |
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12907773 |
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60751119 |
Dec 15, 2005 |
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Current U.S.
Class: |
404/34 ;
405/302.4; 435/183 |
Current CPC
Class: |
C12N 9/78 20130101; C04B
2111/00732 20130101; Y02W 30/97 20150501; Y02W 30/91 20150501; C04B
26/006 20130101; C04B 26/006 20130101; C04B 14/361 20130101; C04B
18/24 20130101; C04B 22/085 20130101; C04B 40/0071 20130101; C04B
2103/0001 20130101; C04B 26/006 20130101; C04B 14/361 20130101;
C04B 18/24 20130101; C04B 22/085 20130101; C04B 24/14 20130101;
C04B 40/0071 20130101 |
Class at
Publication: |
404/34 ;
405/302.4; 435/183 |
International
Class: |
E01C 5/00 20060101
E01C005/00; E02D 3/00 20060101 E02D003/00; C12N 9/00 20060101
C12N009/00 |
Claims
1. A construction article comprising a compacted mixture including
soil and a crop plant biomass microorganism-expressed enzyme
composition.
2. The construction article of claim 1, in which the enzyme
composition includes a ureolytic enzyme.
3. The construction article of claim 2, in which the enzyme
composition includes an active ureolytic enzyme.
4. The construction article of claim 1, in which the mixture
includes a nitrate ion source.
5. The construction article of claim 1, in which the mixture has a
pH within a range of between about 7 and about 8.
6. The construction article of claim 1, in which the enzyme
composition is biodegradable.
7. The construction article of claim 1, in which the enzyme
composition is edible.
8. The construction article of claim 1, in which the soil includes
cohesive colloidal fines passing a 200 mesh screen at a
concentration within a range of between about 8% by weight and
about 30% by weight of the soil.
9. The construction article of claim 1, in which the mixture
includes less than about 10% by weight of cellulosic material.
10. The construction article of claim 1, in which the article is
selected from a group consisting of a brick, block, board, tile,
and paver.
11. A method of stabilizing soil, comprising: mixing together soil,
water and a crop plant biomass microorganism-expressed enzyme
composition to form a mixture; causing the mixture to be shaped
into a selected structure; and causing the structure to be
compacted.
12. The method of claim 11, including mixing together soil, water
and a crop plant biomass microorganism-expressed enzyme composition
that includes a ureolytic enzyme.
13. The method of claim 12, including mixing together soil, water
and a crop plant biomass microorganism-expressed enzyme composition
that includes an active ureolytic enzyme.
14. The method of claim 11, including mixing together soil, water
and a crop plant biomass microorganism-expressed enzyme composition
that includes an enzyme expressed by a ureolytic microorganism.
15. The method of claim 11, including mixing together soil, water,
a crop plant biomass microorganism-expressed enzyme composition,
and a nitrate ion source.
16. The method of claim 11, including mixing together soil, water
and a crop plant biomass microorganism-expressed enzyme composition
that has a pH within a range of between about 7 and about 8.
17. The method of claim 11, including mixing together soil, water
and a biodegradable crop plant biomass microorganism-expressed
enzyme composition.
18. The method of claim 11, including mixing together soil, water
and an edible crop plant biomass microorganism-expressed enzyme
composition.
19. The method of claim 11, including selecting soil including
cohesive colloidal fines passing a 200 mesh screen at a
concentration within a range of between about 8% by weight and
about 30% by weight of the soil.
20. The method of claim 11, including selecting such a mixture
including less than about 10% by weight of cellulosic material.
21. The method of claim 11, including selecting such a mixture
including a water concentration within a range of between about 15%
by weight and about 20% by weight of the mixture.
22. The method of claim 11, in which causing such a mixture to be
shaped into a selected structure includes forming at least one lift
having a thickness within a range of between about 2 inches and
about 6 inches.
23. The method of claim 11, in which causing such a mixture to be
shaped into a selected structure includes forming the selected
structure over a subsurface moistened by a solution including the
crop plant biomass microorganism-expressed enzyme composition.
24. The method of claim 11, including dispersing a crop plant
biomass microorganism-expressed enzyme composition in a water body
confined by a soil subsurface, allowing the composition in the
water body to form such a mixture on the soil subsurface, and
allowing the water body to compact the mixture on the soil
subsurface.
25. The method of claim 11, in which causing such a mixture to be
shaped into a selected structure includes forming an article
selected from a group consisting of a brick, block, board, tile,
and paver.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation and claims priority of
U.S. patent application Ser. No. 12/097,345 filed Dec. 15, 2006,
titled SOIL STABILIZATION SYSTEM which is a 371 application of
International Patent Application Serial No. PCT/US06/48094, filed
Dec. 15, 2006, which claims priority to U.S. Provisional Patent
Application Ser. No. 61/750,119, filed Dec. 15, 2005, the entirety
of all applications are incorporated by reference into this
application.
RELATED APPLICATIONS
[0002] This application claims priority to U.S. Provisional Patent
Application Ser. No. 60/751,119, filed Dec. 15, 2005, titled SOIL
STABILIZATION SYSTEM, which application is incorporated in its
entirety by reference in this application.
BACKGROUND OF THE INVENTION
[0003] 1. Technical Field
[0004] The invention relates to construction articles, including
stabilized soil, and to methods for stabilizing soil.
[0005] 2. Background Art
[0006] Dirt roads, dirt-excavated ponds, levees, railroad
embankments, and other earthen structures have been in widespread
use for eons. However, erosion and other breakdowns in such earthen
structures both at the surface and from within have been perennial
problems. High clay concentrations in soils can lead to
expansion-contraction cycles, and low clay concentrations can
prevent integration of a soil into a monolithic body capable of
enduring water exposure and of withstanding its penetration. Clay
materials strongly bind water with an accompanying expansion or
swelling, making the soil difficult to dry. When clay materials are
thoroughly dried, they contract as the water escapes. This
expansion and contraction often results in general instability of
the dimensions and solidity of soil materials. Air voids in soil
create pathways for soil movement within earthen structures, adding
to this instability. In many soil formations, such as road beds and
pond beds, soil instability causes major construction problems.
Water-containment structures such as lakes frequently accumulate
leaks, causing loss of the contained water, degradation of the
containment structures, and other problems caused by water escape.
Friction among soil particles can require application of high
pressures to compact the soil.
[0007] A continuing need exists for methods of stabilizing soil,
and for solid, self-sustaining articles including soil.
DISCLOSURE OF INVENTION
[0008] In an example of an implementation, a construction article
is provided, including a compacted mixture including soil and a
crop plant biomass microorganism-expressed enzyme composition. As
examples, the construction article may be shaped as a brick, block,
board, tile, or paver. In a further example, the enzyme composition
may include a ureolytic enzyme. The mixture may, as another
example, include a nitrate ion source.
[0009] As another example of an implementation, a method of
stabilizing soil is provided, including: mixing together soil,
water and a crop plant biomass microorganism-expressed enzyme
composition to form a mixture; causing the mixture to be shaped
into a selected structure; and causing the structure to be
compacted. In examples, the method may include mixing together
soil, water and a crop plant biomass microorganism-expressed enzyme
composition that includes a ureolytic enzyme, or such a composition
that includes an enzyme expressed by a ureolytic microorganism. As
a further example, the method may include mixing together soil,
water, a crop plant biomass microorganism-expressed enzyme
composition, and a nitrate ion source. Causing such a mixture to be
shaped into a selected structure may include, in additional
examples, forming an article such as a brick, block, board, tile,
or paver.
[0010] Other systems, methods, features and advantages of the
invention will be or will become apparent to one with skill in the
art upon examination of the following figures and detailed
description. It is intended that all such additional systems,
methods, features and advantages be included within this
description, be within the scope of the invention, and be protected
by the accompanying claims.
BRIEF DESCRIPTION OF DRAWINGS
[0011] The components in the figures are not necessarily to scale,
emphasis instead being placed upon illustrating the principles of
the invention. In the figures, like reference numerals designate
corresponding parts throughout the different views.
[0012] FIG. 1 is a photograph showing a perspective view of an
example of an implementation of a construction article 100.
[0013] FIG. 2 is a flow chart showing an example of an
implementation of a method 200 of stabilizing soil.
MODES FOR CARRYING OUT THE INVENTION
[0014] A construction article is provided, including a compacted
mixture including soil and a crop plant biomass
microorganism-expressed enzyme composition. As examples, the
construction article may be shaped as a brick, block, board, tile,
or paver. In a further example, the enzyme composition may include
a ureolytic enzyme. The mixture may, as another example, include a
nitrate ion source. Further, a method of stabilizing soil is
provided, including: (i) mixing together soil, water and a crop
plant biomass microorganism-expressed enzyme composition to form a
mixture; (ii) causing the mixture to be shaped into a selected
structure; and (iii) causing the structure to be compacted. In
examples, the method may include mixing together soil, water and a
crop plant biomass microorganism-expressed enzyme composition that
includes a ureolytic enzyme, or such a composition that includes an
enzyme expressed by a ureolytic microorganism. As a further
example, the method may include mixing together soil, water, a crop
plant biomass microorganism-expressed enzyme composition, and a
nitrate ion source.
[0015] Soils include chemical substances that may react with other
chemicals if certain conditions are present. These reactions may,
for example, result from attraction between positive and negative
charges in components of the soil and the chemical substances.
Alterations in these charges consequently may change properties of
the soil materials.
[0016] Absorbed water in soil may adhere to the entire surface of
an individual soil particle. This film of water enveloping the soil
particle, which may ultimately govern the expansion and shrinkage
of colloidal soil constituents, may not be completely removable by
purely mechanical methods. However, by means of temperature changes
and addition or removal of water with mechanical pressure, it may
be possible to vary the amount of water held by soil in this
manner. Such variations are attended by swelling or shrinkage.
[0017] Subgrade soil materials, aggregates and mixtures of crushed
rock with soils may behave as electrolyte systems, such that ion
exchanges may occur within the materials. Knowledge of layered
lattice structures that may be present in clay materials, and of
colloid transport and osmotic pressure gradients, may be important
in understanding the behavior of these electrolytic soils. Clays
may have a molecular structure with an anionic, net negative
charge, To maintain electrical neutrality, positively charged
cations may be attracted to and held onto edges and surfaces of
clay particles. These cations are called "exchangeable cations"
because cations of one type may often be exchanged with cations of
another type. When a cation charge in a clay structure is weak, the
remaining negative charge that is not neutralized by the weak
cations may attract polarized water molecules, filling the spaces
of the clay structure with ionized water.
[0018] Individual cations may be unable to disperse freely through
the soil structure because of their attraction to the negatively
charged surfaces of clay particles. This inability to disperse
evenly throughout the soil structure may create an osmotic pressure
gradient in favor of equalization of the cation concentration.
[0019] A movement of water molecules from areas of low cation
concentration to areas of high cation concentration may be
catalyzed to approach equilibrium of the cation concentration
throughout the soil.
[0020] Colloids are amorphous particles without crystalline
structure having an average diameter of less than about a micron.
Particles of this size are influenced by Brownian motion caused by
random thermal gradients. Colloids may be present in a high
concentration in a soil including clay. Colloids may have a net
negative charge that enables them to attract and transport free
cations in the soil as an electrolyte solution. Colloids may
subsequently lose the cations upon passing close to a more strongly
anionic clay particle, leaving the colloids free to then attract
further free cations.
[0021] Both electrochemical and physical effects may have influence
in this transport mechanism. The physical phenomena may be related
to Brownian motion, laminar shear velocity and pore size
distribution. Brownian motion may overcome effects of gravitational
force and prevent deposition of free cations. Laminar shear
velocity may affect a rate of cation exchange with the clay
structure. The pore size distribution may determine a shear
velocity and a proximity of a clay lattice to passing colloids and
cations.
[0022] The electrochemical effects may be related to attractive Van
der Waals forces between positive and negative particles, and to
repulsion forces between multiple ions having the same charge.
[0023] If a solution including cations is introduced into a clay
structure, a microenvironment may be generated in which the cations
may be prevented from dispersing by the adjacent repulsive cations
in the clay lattice. If the soil is not completely saturated with
water, the liquid phase may be moved in a laminar flow through
voids in the soil by capillary forces, leaving a higher
concentration of cations close to the soil surface.
[0024] These capillary forces may generate an osmotic pressure
gradient, which may draw colloidal particles from zones of lower
cation concentration to zones of higher cation concentration. These
colloidal particles may take up some of the free cations, reducing
the ion concentration and the osmotic gradient pressure. This
uptake may result in a hydraulic gradient pressure in the opposite
direction, which may take cation-transporting colloids outward from
a zone of high cation concentration to generate another zone of
high cation concentration where a clay lattice is present,
resulting in a new zone of osmotic pressure and high cation
concentration.
[0025] The flow of cations through clay deposits in soil provides
shrinking and swelling properties in soil. When a cationic material
is added into the soil, the magnitude of neutralization of osmotic
pressure gradients may depend on the valence and size of the
cation. The cation size may determine mobility of the cation.
Smaller cations may travel a greater distance throughout the soil
structure than larger cations. The hydrogen ion is the smallest
cation. Regarding valence, the hydrogen ion may be doubly effective
in affecting the clay structure because even though it has only a
single valence charge, the hydrogen ion produces an effect
equivalent to a valence of two due to its high ionization energy.
Hydrogen cations may be generated in soil in an acidic environment.
Hydrogen cations may exert a strong pull on the clay lattice,
bringing the structure of the soil together and removing trapped
water that may be attracted to clay particles in between sodium and
potassium cations. A loss of bound water results in a strengthening
of the molecular structure of the clay and also in a reduction of
the clay particle size and plasticity. A change in the environment
of the clay in a soil from a basic to acidic state may result in a
persistent change of the molecular structure of the soil.
[0026] Organic cations generated by the growth of vegetation may
have the capacity to exchange with other cations in the clay
lattice. Some organic cations so generated may be huge in size,
equaling the size of smaller ones of the clay particles. These
large organic cations may blanket an entire clay particle,
neutralizing its negative charges and thus reducing its sensitivity
to moisture.
[0027] The electrostatic characteristics of soil particles are
factors in soil-enzyme interactions. In an example, enzymes may
lower the dipole moments of water molecules and dissociation may
then occur to form a hydroxyl (-) ion and a hydrogen (+) ion. The
hydroxyl ion in turn may dissociate into oxygen and hydrogen, and
the hydrogen atom of the hydroxyl ion may be transformed into a
hydronium ion. The hydronium ion can accept or reject either
positive or negative charges, depending on the circumstances. The
finest colloidal particles of soil may be negatively charged. The
enveloping film of absorbed water around soil particles may, as an
example, contain a sufficient number of positive charged metal
ions--such as sodium, potassium, aluminum and magnesium--to ensure
charge equalization with respect to the electrically negative soil
ion. Positively charged hydronium ions or negatively charged
hydroxyl ions may combine with positively charged metal ions in the
water adhering to the surface of the particles.
[0028] Because of the effect of an enzyme in reducing the electric
charges of water molecules, there may be sufficient negative
charges to exert adequate pressure on the positively charged metal
ions to remove them from the absorbed water film. When this
existing electrostatic potential barrier is broken, the metal ions
may migrate freely into the unbound water, and may then be removed
from the soil by washing them out to the soil surface and
evaporating the water. Thus, the film of absorbed water enveloping
the clay particles may be reduced. The clay particles may thereby
lose their swelling capacity and the soil as a whole may acquire a
friable structure. The hydrogen ions, which are liberated in the
dissociation of the water molecules, may once again react with free
hydroxyl ions and form water along with gaseous hydrogen.
[0029] After the absorbed water content of the soil is reduced, the
soil particles may tend to agglomerate. As a result of the
resulting relative movement between particles, the surface area may
be reduced and less absorbed water may be held, which in turn may
reduce the swelling capacity of the soil.
[0030] As an example, crop plant biomass microorganism-expressed
enzyme compositions may be adsorbed by the clay lattice in soil,
and then released upon a complete cycle of exchange with metal
cations such as sodium and potassium. Crop plant biomass
microorganism-expressed enzyme compositions may initially cause the
clay lattice to expand and then to tighten. Crop plant biomass
microorganism-expressed enzyme compositions may also be absorbed by
colloids, enabling enzyme molecules to be transported through soil
electrolyte media. Crop plant biomass microorganism-expressed
enzyme compositions may also may help soil bacteria to release
hydrogen ions, resulting in an acidic pH gradient at the surfaces
of clay particles, which may assist in breaking up the structure of
the clay and facilitating its compaction.
[0031] Crop plant biomass microorganism-expressed enzyme
compositions may combine with large organic molecules in the soil
to form a reactant intermediary, which then may exchange ions with
the clay structure. This ion exchange may break down the clay
lattice and cause clay particles to be blanketed according to the
"cover-up effect", which prevents further absorption of water and
resultant loss of soil density. The crop plant biomass
microorganism-expressed enzymes are then regenerated as the
reactant intermediaries complete a reaction cycle by disassociating
from the clay lattice, and may then react with it again. Because
the reactant intermediary ions are large, little osmotic migration
takes place in them, and a good mixing process may be utilized.
[0032] When the crop plant biomass microorganism-expressed enzyme
compositions are added to a soil, the enzymes may, for example,
increase the wetting and bonding capacity of the soil particles.
These crop plant biomass microorganism-expressed enzymes may allow
soil materials to become more easily wet and more densely
compacted. These crop plant biomass microorganism-expressed enzymes
may also improve chemical bonding to fuse the soil particles
together, creating a more permanent structure that is more
resistant to weathering, wear and water penetration.
[0033] The crop plant biomass microorganism-expressed enzyme
compositions may increase wetting of soil particles, allowing
higher compaction of soil. The crop plant biomass
microorganism-expressed enzyme compositions may cement soil by
forming weak ionic bonds between negative and positive ions present
in the soil structure. The crop plant biomass
microorganism-expressed enzyme compositions may accelerate cohesive
bonding of soil particles and create a tight permanent layer.
[0034] The stabilized soil may have increased compressive strength,
as the crop plant biomass microorganism-expressed enzyme
composition may act as a catalyst to accelerate and strengthen soil
bonding. The enzymes may result in a denser, more cohesive and
stable soil. The stabilized soil may need less compaction effort
and may have improved soil workability. The enzymes may enable
water to lubricate soil particles, helping them slide into a
densest position. The wetting action of the crop plant biomass
microorganism-expressed enzyme composition may enhance this sliding
action during compaction making the soil easier to grade and
allowing a compactor to achieve a targeted soil density with fewer
passes. Water and the crop plant biomass microorganism-expressed
enzyme composition may also assist in bonding together of clay
particles.
[0035] The stabilized soil may have increased density and be
tighter and drier, as voids between soil particles may be reduced
by altering electro-chemical attraction in soil particles and
releasing bound water. The stabilized soil may have lowered water
permeability and resultant greater resistance to deterioration
caused by water penetration, as a tighter soil configuration
reduces the migration of water that otherwise may occur in voids
between particles.
[0036] As an example, macromolecules in a crop plant biomass
microorganism-expressed enzyme composition may provide a
surfactant-like action that aids in the dispersion of soil
particles and provides cementation effects in the soil. When mixed
with water and applied prior to soil compaction, the crop plant
biomass microorganism-expressed enzyme composition may act upon
organic fines contained in the soil through a catalytic bonding
process, producing a strong cementation action. As an example, a
crop plant biomass microorganism-expressed enzyme composition may
lower the surface tension of water, which may promote fast and
thorough penetration of the composition into soil, as well as
dispersal of moisture from the soil. This penetrative action may,
as an example, cause hydrated clay particles to be pressed into and
to fill voids throughout the soil, thus forming a tight, dense,
permanent stratum. A resulting increased lubricity of soil
particles may allow a designated soil density increase to be
reached with less compaction force.
[0037] Soils with too high or too low a moisture content may, for
example, inhibit penetration of a crop plant biomass
microorganism-expressed enzyme composition into the soil. In a
given soil sample there is a proportional amount of water that may
be determined, called the optimum moisture content, at which it is
possible to obtain a maximum compressed density with a given amount
of compactive effort. A crop plant biomass microorganism-expressed
enzyme composition may reduce, by about 25% as an example, the
amount of water required to reach a desired optimum moisture level
of the soil. A crop plant biomass microorganism-expressed enzyme
composition may facilitate this reduced water addition by promoting
rapid saturation and by inhibiting surface evaporation. The crop
plant biomass microorganism-expressed enzyme composition may also
provide cementation action that increases weight bearing
characteristics of soil by promoting a closer binding of soil
particles. This binding may reduce a tendency of the soil to expand
after compaction and may result in a strong, stable earth layer. By
achieving greater bonding density, soil materials may better resist
migration of water.
[0038] FIG. 1 is a photograph illustrating a perspective view of an
example of an implementation of a construction article 100. The
construction article 100 includes a compacted mixture including
soil and a crop plant biomass microorganism-expressed enzyme
composition. FIG. 1 shows that the construction article 100 has a
firm, self-sustaining structure and an appearance similar to that
of a concrete block. As an example, the construction article 100
may, as shown in FIG. 1, be shaped as a brick. The brick shape may
include projecting and recessed portions suited for assembling and
bonding together a plurality of such construction articles 100 in a
modular arrangement to collectively form a structure such as a
wall. It is understood by those skilled in the art that the
construction article 100 may take other shapes (not shown), such as
a block, board, tile, or paver.
[0039] The construction article 100 includes a compacted mixture
including a crop plant biomass microorganism-expressed enzyme
composition. For example, such a composition may include an enzyme
expressed by microorganisms in fermentation of a crop plant
biomass. Such microorganisms may include, as examples, bacteria and
fungi. In an example, ureolytic microorganisms may be selected.
Urea is converted by certain microorganisms into ammonium
carbonate, releasing ammonium cations that are then converted by
certain microorganisms into nitrite ions and then into nitrate
ions. Nitrate ions are taken up as a nutrient by certain plants.
There are other sources of nitrate ions which are commonly added to
soil. Ammonium nitrate, ammonium sulfate, ammonium carbonate and
ammonium bicarbonate as examples, are direct sources of ammonium
cations for in situ conversion into nitrate ions. Ammonium nitrate
is additionally a direct source of nitrate ions. Ammonia, as
another example, ionizes into ammonium ions. Fermentation may
include incubation of selected microorganisms together with a crop
plant biomass under conditions suitable for growth of the
microorganisms. The selected microorganisms may then collectively
express such an enzyme in a harvestable amount and concentration.
Selected microorganisms may further express a plurality of enzymes.
A crop plant biomass for fermentation may include, as examples,
selected parts of one or a plurality of plants. A crop plant may
include, for example, a type of plant selected and cultivated as a
crop. As another example, a crop plant biomass may include all
parts or selected parts of a crop plant. A crop plant may, for
example, include one or a mixture of the following: cereals,
vegetables, roots, tubers, fruits, oil crops, pulses, vegetable
fibers, nuts, forestry products, and horticultural products.
[0040] As an example, an enzyme may be a biologically-produced
proteineic substance having specific activation in which the enzyme
combines with its substrate in a stereoscopic position such that
the enzyme causes changes in the electronic configuration around
certain susceptible molecular bonds, catalyzing some bond formation
or breakage in the substrate. In another example, "catalyzing" may
include causing a specific chemical reaction to proceed at an
accelerated rate. In one example, the enzyme composition may
include an enzyme expressed by ureolytic microorganisms. As a
further example, the enzyme composition may include a ureolytic
enzyme. In an additional example, the enzyme composition may
include an active ureolytic enzyme, having ureolytic activity. Such
an active ureolytic enzyme may convert urea that may be present in
the crop plant biomass microorganism-expressed enzyme composition
or in the soil, into cationic ammonium ions. In an example, the
crop plant biomass microorganism-expressed enzyme composition may
include a plurality of enzyme groupings. As another example, each
of a plurality of enzyme groupings may have enzymatic activity
catalyzing the same or different steps of the nitrogen cycle.
According to the nitrogen cycle, for example, amine moieties in
amino acids and in other nitrate ion sources may be successively
converted into ammonium ions, nitrite ions, and nitrate ions.
Nitrate ion sources including ammonium ions, nitrite ions, or
nitrate ions may, for example, be included in a crop plant biomass
microorganism-expressed enzyme composition. As an additional
example, the enzyme composition may include an enzyme synthesized
by a plant. Such a plant enzyme may remain enzymatically active in
the enzyme composition.
[0041] As additional examples, the enzyme composition may include
one or more of the following types of enzymes: urease, hydrolase,
amidohydrolase, oxidoreductase, transferase, lyase, aspartase,
1-glutaminase, dehydrogenase, acid phosphatase, alkaline
phosphatase, arylsulfatase, betaglucosidase, amylase, catalase,
alkaline phosphomonoesterase, phosphodiesterase, deaminase,
invertase, cellulase, protease, asparaginase, amidase, chitinase,
lipase, carbohydrase, phenoloxidase, peroxidase, laccase, lipase,
aminopeptidase, and glucose oxidase.
[0042] Further enzymes that may be utilized are disclosed in Zahir,
Z. A., et al., "Soil Enzymes Research: A Review", OnLine Journal of
Biological Sciences, Vol. 1, No. 5, pp. 299-307 (2001), the
entirety of the article of which is incorporated into this
application by reference. Termite and ant enzymes may, as examples,
also be utilized.
[0043] The crop plant biomass microorganism-expressed enzyme
composition may, for example, be edible. In a further example, the
crop plant biomass microorganism-expressed enzyme composition may
generally be non-harmful to fish, animals, other wildlife,
vegetation, and watersheds. The crop plant biomass
microorganism-expressed enzyme composition may, for example, be
biodegradable.
[0044] The crop plant biomass microorganism-expressed enzyme
composition may not irritate skin tissue and may not cause rashes
or bums. The crop plant biomass microorganism-expressed enzyme
composition may, for example, contain no combustible materials and
may be non-explosive. The crop plant biomass
microorganism-expressed enzyme composition may, as an example, be
non-gaseous and may be suitable for storage in poorly ventilated
areas.
[0045] The microorganisms utilized in fermenting the crop plant
biomass may, for example, be substantially inactive in the crop
plant biomass microorganism-expressed enzyme composition. As a
further example, a pH of the crop plant biomass
microorganism-expressed enzyme composition may be a substantially
neutral pH within a range of between about 7 and about 8.
[0046] In an example, the construction article 100 may include a
crop plant biomass microorganism-expressed enzyme composition that
may include a nitrate ion source. As examples, nitrate ion sources
include amino acids, urea, and compositions including ammonium,
nitrite, or nitrate ions. Urea, for example, may be converted by
the enzymes or by microorganisms in the soil into ammonium ions. A
nitrate ion source may be added to the construction article 100,
for example, in one or more of the following forms: ammonium ions
(NH.sub.4.sup.+), nitrite ions (NO.sub.2.sup.-), nitrate ions
(NO.sub.3.sup.-), and amines such as urea (CO(NH.sub.2).sub.2.
[0047] The construction article 100 includes a compacted mixture
including soil. Soil may be utilized in the construction article
100 that includes cohesive colloidal fines able to pass a 200 mesh
screen, at a concentration within a range of between about 8% by
weight and about 30% by weight of the soil. Such a concentration
may include sufficient fines for adequate soil cohesiveness while
not having excessive potential for expansion and contraction. Such
cohesive fines may include clays, which attract water molecules and
may be characterized by high water retention as well as marked
expansion and contraction dependent on uptake and loss of such
water, or other fines characterized by high water retention. In
further examples, a soil may be selected that includes cohesive
colloidal fines passing a 200 mesh screen at a concentration within
a range of between about 8% by weight and about 20% by weight of
the soil, or between about 8% by weight and about 11% by weight of
the soil, or between about 15% by weight and about 20% by weight of
the soil. In further examples, a soil having a well-graded
distribution of sizes of particles may be utilized. Such a soil
may, as an example, be readily compacted into a dense construction
article 100 as the various sizes of particles may collectively fill
voids and fit tightly together.
[0048] In an example, the construction article 100 may include less
that about 10% by weight of vegetation. Vegetation may include
cellulosic materials, such as straw. As one example, the
construction article 100 may be formed without being subjected to
heat curing such as firing in a kiln at an elevated temperature.
Utilizing a crop plant biomass microorganism-expressed enzyme
composition may, as examples, increase the resilient modulus and
shear strength of the construction article 100.
[0049] As illustrated, the construction article 100 is compacted.
For example, the construction article may have a dense structure
resulting from formation of the construction article 100 by
compaction, under an elevated pressure, of a mixture including
soil, water and a crop plant biomass microorganism-expressed enzyme
composition. Compaction pressure in pounds per unit surface area
may be utilized in forming a construction article 100 comparable to
a compaction pressure in pounds per unit area generated by road
construction equipment such as a drum roller, a sheeps foot roller,
or a vibrating roller.
[0050] FIG. 2 is a flow chart showing an example of an
implementation of a method 200 of stabilizing soil. In an example,
the method 200 may include (i) mixing together soil, water and a
crop plant biomass microorganism-expressed enzyme composition to
form a mixture; (ii) causing the mixture to be shaped into a
selected structure; and (iii) causing the structure to be
compacted.
[0051] The method 200 begins at step 205 and at step 210, the soil
to be stabilized may be fragmented. As examples, the soil to be
stabilized may be soil utilized to form a road, parking lot or
trail. The surface of such soil to be stabilized may be dense,
dusty and hard when dry, even though the same surface may be soft
and muddy when wet. Accordingly, to facilitate mixing the soil to
be stabilized together with water and a crop plant biomass
microorganism-expressed enzyme composition, breaking up such a dry,
dense, hard surface may be carried out at step 210. For example,
the soil to be stabilized may be scarified with road-working
equipment suitable to scratch the soil surface to a selected depth.
The scarified soil may then be subjected to further steps of the
method 200. The hard soil surface below the scarified soil may be
referred to as the subsurface. A selected scarification depth may
be determined based on the intended type of usage for the
stabilized soil surface. For example, the axle weight of vehicles
expected to utilize a road may be utilized to determine the depth
of soil that may need to be stabilized on a subsurface to bear such
weight. It is understood that if a given stabilized soil depth is
found insufficient to support the actual vehicular traffic through
a selected life cycle for a road, then a greater stabilized soil
depth may be selected.
[0052] At step 215, a crop plant biomass microorganism-expressed
enzyme composition may be formulated at a selected concentration
for mixing at step 220 with the soil to be stabilized. Such a crop
plant biomass microorganism-expressed enzyme composition may be
initially prepared as discussed above in connection with the
construction article 100 shown in FIG. 1. As an example, such a
crop plant biomass microorganism-expressed enzyme composition may
include a concentrated solution of such an enzyme. A dilution
factor for such a concentrated enzyme solution may be selected for
efficient utilization of the enzymes. As an example, one gallon of
a concentrated enzyme solution may be sufficient for mixing with
about 1,000 gallons of water, for subsequently mixing with about
165 cubic yards of soil. In another example, 15 gallons of a
concentrated enzyme solution may be sufficient for mixing with an
amount of soil equivalent to a 25-foot wide roadway having a depth
of 6 inches and a length of one mile. Concentrated enzyme solution
may be added to a water tank for mixing after the water has been
filled into the tank to prevent excessive foam generation.
[0053] At step 220, the soil to be stabilized, water, and a crop
plant biomass microorganism-expressed enzyme composition are
combined to form a mixture. In an example, a reasonable effort may
be made before forming such a mixture to remove vegetation such as
cellulosic materials including wood, mulch and leaves from the
surface of the soil to be stabilized. For example, a concentration
of cellulosic materials in the soil to be stabilized may be reduced
to less than about 10% by weight. Where step 210 may be carried out
to fragment the soil, removal of such cellulosic materials may be
carried out before the fragmentation is done. A concentration of
cohesive colloidal fines in the soil to be stabilized may further
be determined and adjusted. To determine such a concentration, ASTM
International Standard No. D422-63(2002)e1, "Standard Test Method
for Particle-Size Analysis of Soils" ("ASTM D422") may be utilized,
as well as other testing methods. The ASTM D422 article is
incorporated in its entirety in this application by reference. The
concentration of cohesive colloidal fines in soil to be stabilized
may be upwardly and downwardly adjusted by additions to the soil of
fines or of fines-free soil, respectively. Suitable concentrations
of cohesive fines may, as examples, be those within the same ranges
as discussed above in connection with the construction article 100.
As another example, a soil may be selected that includes cohesive
colloidal fines passing a 200 mesh screen at a concentration in
excess of about 95% by weight. Where a soil including cohesive
colloidal fines passing a 200 mesh screen at a concentration of
less than about 8% by weight is selected, such a concentration may
as an example be increased by addition of "dirty fines" to the
soil. Such "dirty fines" may generally include, for example,
cohesive fines having particle sizes such that about 15% to about
20% by weight of the fines pass a 200-mesh screen.
[0054] Where the soil to be stabilized is a lake bed for example,
step 220 may be carried out without removal of the lake water.
Where a maximum depth of the lake water is no greater than about 8
feet for example, lake water removal may not be needed. To carry
out step 220, about 1 gallon of concentrated crop plant biomass
microorganism-expressed enzyme composition may be applied to the
lake bed per 6,000 square feet of lake surface area. In
application, the concentrated crop plant biomass
microorganism-expressed enzyme composition may be poured into the
lake from the windward side and around the perimeter, or
distributed evenly across the lake from a boat. The concentrated
crop plant biomass microorganism-expressed enzyme composition may
then form a mixture with the lake bed soil subsurface. Following
addition of the concentrated crop plant biomass
microorganism-expressed enzyme composition, further water entry
into the lake may be prevented for a curing period. For example,
the curing period may be at least about 3 days. The weight of the
lake water may compact the mixture into the lake bed soil
subsurface. The lake bed may be scarified before or after adding
the crop plant biomass microorganism-expressed enzyme composition.
Chains may be dragged across the lake bed. Further, analysis of the
soil composition of the lake bed may be carried out. A target soil
composition for the lake bed may, for example, be selected that
includes cohesive colloidal fines passing a 200 mesh screen at a
concentration within a range of between about 25% by weight and
about 30% by weight of the soil. If a concentration of cohesive
fines in the lake bed is deficient, then cohesive fines such as
bentonite clay may be dispersed over the lake bed. It is understood
that the above discussion regarding lake beds is applicable to
other types of water bodies confined by a soil subsurface, such as
containment structures, canals, landfills, reservoirs, lake beds,
drainage areas, mine leach ponds, water ducts, and levees.
[0055] Mixing the crop plant biomass microorganism-expressed enzyme
composition with the soil to be stabilized may be carried out for
example, as needed, by blading the soil into a windrow with road
building equipment. The windrow may then be bladed from side to
side across the roadway over the subsurface. A grader may also be
utilized. In another example, the soil to be stabilized may be
removed from the subsurface, mixed elsewhere with the crop plant
biomass microorganism-expressed enzyme composition, and then
deposited onto the subsurface. A moisture content of the soil to be
stabilized may be determined, and a suitable amount of water may be
mixed with the soil. A hydrometer may be utilized, for example, to
determine and monitor the moisture concentration of the soil to be
stabilized. An optimum water concentration in the soil within a
range of between about 15% and about 20% by weight may, for
example, be selected. A water concentration in the soil that is
within a range of between about 2% by weight and about 3% by weight
below such an optimum water concentration may then for example be
selected as a target water concentration in carrying out step 220.
Such a water concentration may be adequate for mixing, while
allowing a margin of error to avoid excessive water addition that
might necessitate drying the soil. A rough determination of an
appropriate water concentration in the soil may be made by
attempting to make a small, cohesive ball of soil between one's
fingers. When a soil to be stabilized has a water concentration
that is too high, the soil may be dried, as an example, by
successively blading the soil in windrows to facilitate water
evaporation.
[0056] Step 220 may be carried out, for example, at a time when the
daytime ambient temperature reaches a high of at least about 50
degrees Fahrenheit, and when the nighttime ambient temperature
reaches a low that is above about 32 degrees Fahrenheit.
[0057] A crop plant biomass microorganism-expressed enzyme
composition may be applied to a dusty soil surface for dust control
at a dilution rate, for example, of about 10,000 gallons water to 1
gallon of the concentrated crop plant biomass
microorganism-expressed enzyme composition.
[0058] In step 225, the mixture including a crop plant biomass
microorganism-expressed enzyme composition and the soil to be
stabilized, may be allowed to sit for awhile before shaping the
soil in step 235. Step 225 may facilitate absorption of the crop
plant biomass microorganism-expressed enzyme composition into the
soil. For example, step 225 may include leaving the mixture
overnight in a windrow.
[0059] At step 230, the water concentration of the mixture
including a crop plant biomass microorganism-expressed enzyme
composition and the soil to be stabilized may be determined and
potentially adjusted. In an example where the mixture is allowed to
sit overnight in step 225, step 230 may be carried out to ensure
that the water concentration of the mixture remains sufficient.
Hydrometer monitoring may be utilized, and a selected amount of
additional water may be added to and mixed with the soil. Such
additional water may include a crop plant biomass
microorganism-expressed enzyme composition. A suitable dilution
factor for a concentrated crop plant biomass
microorganism-expressed enzyme composition may be, for example,
about 1 gallon of concentrate in about 10,000 gallons of water,
although other concentrations may be utilized. After applying the
enzyme composition to the soil, as necessary, additional water may
be applied to bring the moisture content closer to the amount
needed for proper compaction.
[0060] At step 235, the mixture including a crop plant biomass
microorganism-expressed enzyme composition and the soil to be
stabilized is shaped into a selected structure. For example, the
soil to be stabilized may be deposited onto the subsurface, earlier
discussed, in one or more lifts. Each such lift may, as an example,
have a thickness within a range of between about 2 inches and about
6 inches, or within a range of between about 2 inches and about 3
inches. Lifts within such thicknesses may be high enough so that
compaction of the selected structure may be done in a minimized
series of passes, while not being too high for the selected
compaction equipment to be effective. Lifts having a thickness of
less than about 2 inches and greater than about 6 inches may also
be utilized. The subsurface may be moistened with a crop plant
biomass microorganism-expressed enzyme composition diluted in water
before depositing a first lift. A dilution of 1 gallon of
concentrated crop plant biomass microorganism-expressed enzyme
composition in 10,000 gallons of water may be utilized, among other
concentrations. A surface on which any successive lifts are then
deposited may be similarly moistened before depositing each lift,
as needed. A total accumulation of up to about 24 inches of soil
lifts or more may be deposited on a subsurface. In addition to
forming selected soil lifts, it is understood that shaping of a
selected structure may include providing for proper drainage
including crowning and side drainage. In a further example, step
235 may include causing the mixture to be shaped into a selected
structure including a brick, block, board, tile, or paver.
[0061] In step 240, the selected structure is compacted. Where
multiple lifts are to be deposited, each successive lift may be
compacted before deposition of the next lift. The soil to be
stabilized may be compacted utilizing static weight, kneading, or
vibration, among other known methods of compaction. Static weight,
kneading and vibration may, for example, be applied to compact a
soil lift utilizing a drum roller, a sheeps foot roller, and a
vibrating roller, respectively. The vibration in a vibrating roller
may be turned off after two compaction passes, to avoid fracturing
previously compacted soil lifts. Compaction of soil lifts may be
determined and monitored utilizing, for example, the American
Association of State Highway and Transportation Officials
("AASHTO") Standard Method T 99-01 "Moisture-Density Relations of
Soils Using a 5.5-Pound Rammer and a 12-Inch Drop", the entirety of
which is incorporated into this application by reference. Each lift
may be compacted to at least about 95% as determined by AASHTO
Method T-99-01, or to other compaction percentages in practice.
Compaction of soil lifts may also be determined and monitored, as
an example, utilizing ASTM International Standard D698-00ae1
"Standard Test Methods for Laboratory Compaction Characteristics of
Soil Using Standard Effort", the entirety of which is incorporated
into this application by reference. As an example, the compaction
density may be about 98 to 102% of optimum density, as measured
using ASTM-D-698. In addition, soil density may be determined and
monitored, as an example, utilizing a nuclear moisture-density
meter. Compaction densities of up to 100-105 percent may, for
example, be reached. Compaction may be achieved and then the
surface may be worked to a smooth finish with a rubber tire or
smooth steel-wheeled roller, or other smoothing devices.
[0062] The selected structure may be a construction article 100.
Step 240 may then be carried out by applying compressive pressure
to a mixture including soil and a crop plant biomass
microorganism-expressed enzyme composition confined to a selected
article shape such as that of a brick, block, board, tile, paver,
or other construction article.
[0063] Final shaping of the selected structure may be carried out
at step 245. Following completion of deposition and compaction of
soil lifts, parts of such lifts may be removed and pushed aside,
leaving behind a compacted soil structure having a selected shape.
As an example, a new lake bed may be constructed by forming a
perimeter berm in a series of compacted lifts having roughly the
selected lake bed dimensions, and then blading the compacted soil
structure to selected elevations. Where a liner is installed, the
top 10 to 12 inches of a soil base may, for example, be subjected
to the method 200 to provide a stable base for most lake bed
liners.
[0064] In another example, at step 250 final compaction of the
selected soil structure may be carried out. In an example, step 250
may be utilized following step 245 to re-compact surface soil
disturbed by the final shaping.
[0065] At step 255, the selected soil structure may be allowed to
cure undisturbed. In an example, curing may be completed in warm
ambient temperatures over a period of about 3 days. As an example,
the selected structure may become cured without application of
heat, provided that a daytime high temperature of at least about 50
degrees Fahrenheit is reached and provided that a nighttime low
temperature measured at the soil surface is above about 32 degrees
Fahrenheit, in most instances.
[0066] In step 260, a wear surface may be applied over the
stabilized soil. As an example, high speed road traffic may merit
protection of the stabilized soil by application of a protective
layer. In examples, a chip seal or an asphalt layer may be applied.
A 3 to 5 day curing period for the soil stabilized by the method
200 may be allowed before such application.
[0067] The stabilized soil surface may be moistened before
application of the protective layer by a diluted crop plant biomass
microorganism-expressed enzyme composition in the same manner as
earlier discussed. Further, the stabilized soil surface may be
dressed to remove surface bumps and pits, so that a smooth
protective layer may be applied. The method 200 may then end at
step 265.
[0068] The soil stabilized by the method 200 may, as examples, have
increased resilient modulus and increased shear strength. As an
example, the resilient modulus of a soil to be stabilized may be
relatively increased by a factor within a range of between about
30% and about 100%. As another example, the resilient modulus of a
soil to be stabilized may be relatively increased by a factor
within an average range of between about 69% and about 77%. In
another example, the shear strength of a soil to be stabilized may
be relatively increased by an average factor within a range of
between about 31% and about 39%. Development of maximum resilient
modulus may be delayed for a period of time, in certain instances
up to about 5 months after completion of the method 200.
Development of maximum shear strength may be delayed for a period
of time, in certain instances up to about 4 months after completion
of the method 200. The resilient modulus of soil may be determined
by utilizing the test procedures in National Cooperative Highway
Research Program Project 1-28A, "Laboratory Determination of
Resilient Modulus for Flexible Pavement Design", the entirety of
which is incorporated in this application by reference. Further,
the resilient modulus of soil may further be determined by
utilizing the test procedures in Strategic Highway Research Program
("SHRP") Protocol 46 "Resilient Modulus of Unbound Granular
Base/Subbase Materials and Subgrade Soils", as modified in
SHRP-P-693, "Type II Unbound Cohesive Subgrade Soil Synthetic
Reference Sample Program", Washington, D.C. 1994, the entirety of
which is incorporated in this application by reference.
[0069] The soil stabilized by the method 200 may exhibit decreased
surface water permeability, increased structural integrity,
increased surface wear resistance, increased load bearing capacity,
and increased resistance to surface deterioration due to weather
exposure including frost heaving.
[0070] Soil stabilization by the example method 200 may be utilized
for dust control, trails, roads, parking lots, slope stabilization
including railway embankments, air strips, pipe bedding, and soil
surfaces intended to receive continuous water exposure including
containment structures, canals, landfills, reservoirs, lake beds,
drainage areas, mine leach ponds, water ducts, and levees, in
addition to other applications. In slope stabilization
applications, as an example, no vegetation such as straw and no
matting may need to be applied.
[0071] The foregoing description of an implementation has been
presented for purposes of illustration and description. It is not
exhaustive and does not limit the claimed inventions to the precise
forms disclosed. Modifications and variations are possible in light
of the above description or may be acquired from practicing the
invention. Note also that the implementation may vary. In addition
to the article and method features described in this document,
those skilled in the art will recognize that other features may be
included or offered in connection with the articles and methods and
should be viewed as within the scope of this invention. For
example, the articles may be formed into any selected shape for
which a composition including soil may have utility. As another
example, the soil stabilization methods may be applied to any soil
surface that may benefit from a hardening and a reduction in water
permeability. The claims and their equivalents define the scope of
the invention.
* * * * *