U.S. patent application number 15/584640 was filed with the patent office on 2017-08-17 for high value organic-enhanced inorganic fertilizers.
This patent application is currently assigned to Anuvia Plant Nutrients Corporation. The applicant listed for this patent is Anuvia Plant Nutrients Corporation. Invention is credited to Jeffrey C. Burnham, James P. Carr, Gary L. Dahms, Barry R. Jarrett.
Application Number | 20170232419 15/584640 |
Document ID | / |
Family ID | 46925453 |
Filed Date | 2017-08-17 |
United States Patent
Application |
20170232419 |
Kind Code |
A1 |
Dahms; Gary L. ; et
al. |
August 17, 2017 |
High Value Organic-Enhanced Inorganic Fertilizers
Abstract
The invention is directed to manufacture of fertilizer having
commercial levels of nitrogen supplemented with organic substances.
The process treats organic matter with acid causing hydrolysis of
organic polymers after which the mix is injected with nitrogen. The
resultant sterilized and liquefied organic matter is disbursed over
recycled material for the production of granules. Because the
process allows for the controlled addition of acids and ammonia,
desired levels of components can be achieved. The process is
scalable, odor controlled and safe thereby allowing for the
location of biosolid processing facilities in most any location.
Further, the fertilizer of the invention provides a dual
nitrogen-release profile when applied to crops. After application
to soil, fertilizer of the invention releases an immediate bolus of
nitrogen, similar to traditional ammonium sulfate, followed by
continued slow release of nitrogen typically over a season.
Inventors: |
Dahms; Gary L.; (Mesquite,
NV) ; Carr; James P.; (Bradenton, FL) ;
Burnham; Jeffrey C.; (Marco Island, FL) ; Jarrett;
Barry R.; (Olive Branch, MS) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Anuvia Plant Nutrients Corporation |
Zellwood |
FL |
US |
|
|
Assignee: |
Anuvia Plant Nutrients
Corporation
Zellwood
FL
|
Family ID: |
46925453 |
Appl. No.: |
15/584640 |
Filed: |
May 2, 2017 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14642842 |
Mar 10, 2015 |
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15584640 |
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13432709 |
Mar 28, 2012 |
8992654 |
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14642842 |
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13104127 |
May 10, 2011 |
9695092 |
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13432709 |
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12033809 |
Feb 19, 2008 |
7947104 |
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13104127 |
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61615258 |
Mar 24, 2012 |
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61569007 |
Dec 9, 2011 |
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61468157 |
Mar 28, 2011 |
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60890422 |
Feb 16, 2007 |
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Current U.S.
Class: |
422/630 |
Current CPC
Class: |
B01J 19/245 20130101;
C05G 5/12 20200201; B01J 2/12 20130101; C05G 5/00 20200201; B01J
2219/24 20130101; B01J 2/006 20130101; C05D 3/00 20130101; C05D
9/02 20130101; Y02W 10/37 20150501; B01J 2219/00006 20130101; C05C
3/00 20130101; B01J 2219/00051 20130101; B01J 2219/00162
20130101 |
International
Class: |
B01J 19/24 20060101
B01J019/24; C05G 3/00 20060101 C05G003/00; B01J 2/12 20060101
B01J002/12; C05C 3/00 20060101 C05C003/00; B01J 2/00 20060101
B01J002/00 |
Claims
1. A system for the manufacture of a fertilizer comprising: a mixer
configured to blend organic material with an odor control agent
forming blended organic material; a first reaction or pressure
vessel containing one or more inlets configured for the blended
organic material and an acid, wherein the blended organic material
is mixed with the acid and heated to a first predetermined
temperature and pressurized to a first predetermined pressure for a
period of time forming a liquid; a second reaction or pressure
vessel containing one or more inlets configured for the liquid and
an ammonia source, wherein the liquid is mixed with ammonia from
the ammonia source and heated to a second predetermined temperature
and pressurized to a second predetermined pressure for a second
period of time; and a granulator wherein the ammoniated liquid is
mixed with preformed granules and heated to form dried granules of
the fertilizer.
2. The system of claim 1, wherein the ammonia source is liquefied
or gaseous ammonia under pressure.
3. The system of claim 1, wherein the first and second reaction or
pressure vessels each contain an agitator.
4. The system of claim 1, further comprising a screening process to
size fertilizer granules, and one or more cooling and coating
apparatus to reduce temperature and control dust prior to
storage.
5. The system of claim 1, further comprising: a conveyer for
transporting the organic material to the mixer and another conveyer
for transporting the blended organic material to the first reaction
or pressure vessel; a pressurized piping system that transports
acidified organic material from the first reaction or pressure
vessel to the second reaction or pressure vessel, ammonia into the
second reaction or pressure vessel; and disperses the ammoniated
liquid to the granulator.
6. The system of claim 1, further comprising one or more screens
for selecting granules of a predetermined size and a rotary cooler
for cooling and polishing the sized granules.
7. The system of claim 1, further comprising a dust control
apparatus that collects and recycles dust from the granulator.
8. The system of claim 1, further comprising a water recovery
system whereby water extracted from the organic material during
processing is recovered and recycled.
9. The system of claim 1, wherein the first reaction or pressure
vessel is a pipe-cross reactor, the second reaction or pressure
vessel is a pipe-cross reactor, or both the first and second
reaction or pressure vessels are each pipe-cross reactors.
10. The system of claim 1, wherein the first reaction or pressure
vessel is a reaction vessel and the second first reaction or
pressure vessel is a pressure vessel.
11. The system of claim 1, wherein the first and second reaction or
pressure vessels are the same vessel.
12. A system for the manufacture of a fertilizer comprising: a
mixer that blends organic material; one or more first reaction or
pressure vessels containing one or more inlets configured for the
blended organic material and an acid, wherein the blended organic
material is mixed with the acid provided through the one or more
inlets that liquefies the organic material generating both heat and
pressure within the vessel; one or more second reaction or pressure
vessels containing one or more inlets configured for input of the
liquid organic material from the one or more first reaction or
pressure vessels and an ammonia inlet from an ammonia source that
is added to the one or more second reaction or pressure vessels
after the organic material has been liquefied; and a granulator
wherein the ammoniated liquid is mixed with preformed granules and
heated to form dried granules of the fertilizer.
13. The system of claim 12, wherein the preformed granules are
recycled fertilizer granules.
14. The system of claim 12, wherein the ammonia source is liquefied
or gaseous ammonia under pressure.
15. The system of claim 12, wherein the one or more first and/or
second reaction or pressure vessels contain an agitator.
16. The system of claim 12, further comprising a screening process
to size fertilizer granules, and one or more cooling and/or coating
apparatus to reduce temperature and control dust prior to
storage.
17. The system of claim 12, further comprising: a conveyer for
transporting the organic material to the mixer and another conveyer
for transporting the blended organic material to the one or more
first reaction or pressure vessels; a pressurized piping system
that transports the acid to the one or more first reaction or
pressure vessel and/or ammonia to the one or more second reaction
or pressure vessels; and disperses the ammoniated liquid to the
granulator.
18. The system of claim 12, further comprising one or more screens
for selecting granules of a predetermined size and a rotary cooler
for cooling and polishing the sized granules.
19. The system of claim 12, further comprising a dust control
apparatus that collects and recycles dust from the granulator.
20. The system of claim 12, further comprising a water recovery
system whereby water extracted from the organic material during
processing is recovered and recycled.
Description
REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 13/432,709 filed Mar. 28, 2012, which issued as U.S. Pat. No.
8,992,654 on Mar. 31, 2015 and claims priority to U.S. Provisional
Application No. 61/468,157 filed Mar. 28, 2011, U.S. Provisional
Application No. 61/569,007 filed Dec. 9, 2011, and U.S. Provisional
Application No. 61/615,258 filed Mar. 24, 2012, and a
continuation-in-part of U.S. application Ser. No. 13/104,127 filed
May 10, 2011, which is pending and is a continuation of U.S.
application Ser. No. 12/033,809 filed Feb. 19, 2008, which issued
as U.S. Pat. No. 7,947,104 May 24, 2011, and claims priority to
U.S. Provisional Application No. 60/890,422 filed Feb. 16, 2007,
all of which are specifically and entirely incorporated by
reference.
BACKGROUND
[0002] 1. Field of the Invention
[0003] This invention is directed to methods, systems, and
processes for the manufacturing of fertilizer and the fertilizer
product manufactured by these methods. In particular, the invention
is also directed to the manufacture of fertilizers with
predetermined concentrations or absences of nitrogen, phosphate
and/or potassium.
[0004] 2. Description of the Background
[0005] Sludge today is estimated to be produced at a rate of over 8
million dry metric tons annually or roughly about 64 dry pounds of
biosolids for every individual in the United States. The term
sludge has been replaced with the term biosolid which includes all
forms of municipal wastes such as, for example, domestic septage,
farm and factory organic wastes that are collected or otherwise
find their way to waste-water treatment, sewer run offs,
pharmaceutical wastes including fermentation and processing wastes,
microbial digests, food wastes and food byproducts, animal manures,
digested animal manures, organic sludge, organisms and
microorganisms and all combinations thereof. Most all industrial
wastes find their way into municipal sludge or are otherwise
disposed of in landfills or as may be common in the particular
industry. As can be envisioned, all forms of discarded material can
and typically do wind up in municipal sludge including
biologically-active molecules such as pharmaceuticals as well as
their metabolized products, paper, plastics, metals and most all
forms of garbage.
[0006] Biosolids are collected typically by municipalities through
existing infrastructures such as sewers and other types of
residential and industrial plumbing systems. Collected material is
sent to one or more central facilities referred to as waste-water
treatment plants. At these plants water is separated from the
solids and sent through purification procedures for reclamation.
The solids are either burned or transported by truck for burial or
by barge for dumping into the ocean. Burning or incineration has
become more common in part because of the awareness the dangers of
unprocessed biosolids. In all biosolids are assumed to be not only
harmful chemicals but also bioactive compounds, and pathogens.
Federal, state and local regulations exist that strictly control
the handling of biosolids for the safety of both workers and the
public. But whether burned or buried, such procedures are highly
inefficient and extremely costly.
[0007] Burning destroys most of the harmful materials present in
the biosolids, but the cost in damage to the environment is always
tremendous. Incinerators have been built specifically to deal with
municipal waste. These incinerators create huge amounts of
contaminated smoke spoiling the air within hundreds of square miles
around the facility. The smoke that's emitted contains whatever
contaminants as were present in the biosolids such as metals and
other non-combustible components. Those contaminants settle onto
fields and bodies of water creating ecological nightmares around
the plants and sometimes for great distances down-wind of the
plants. Although burning can produce energy, energy production is
highly inefficient requiring huge amounts of biosolids to become
cost effective. The amount of energy produced is always small in
comparison to the amount of material incinerated. Even after
burning, enormous amounts of soot remain that must be removed and
disposed. As compared to the original biosolid, the soot is devoid
of any positive impact to the environment whatsoever and is simply
and unceremoniously buried or dumper into the ocean. Overall
burning negatively increases the impact of biosolid disposal to the
environment and for many years into the future.
[0008] Biosolids that have been treated to some degree of
processing are classified according to federal standards
established by the United States Environmental Protection Agency as
Class A or Class B. "Class A" biosolids are considered free of
detectable pathogens and sufficiently safe as a fertilizer for
animal or human crop usage. Pathogens such as, for example,
Salmonella sp. bacteria, fecal coliform indicator bacteria, enteric
viruses, and viable helminth ova are below detectable levels. When
pathogens can be detected in the biosolids, the USEPA has classed
such treated biosolids as "Class B" implying that they are of a
lower standard than the "Class A" treated biosolids. Because Class
B biosolids contain pathogen indicators--and therefore potential
pathogens, they are restricted in the manner by which they can be
applied to animal and human crops.
[0009] The Part 503 rule (Title 40 of the Code of Federal
Regulations, Part 503, incorporated herein by reference) lists six
alternatives for treating biosolids so they can be classified in
Class A with respect to pathogens. Alternative 1 requires biosolids
to be subjected to one of four time-temperature regimes.
Alternative 2 requires that biosolids processing meets pH,
temperature and air-drying requirements. Alternative 3 requires
that when biosolids are treated in other processes, it must be
demonstrated that the process can reduce enteric viruses and viable
helminthes ova, and operating conditions used in the demonstration
after pathogen reduction demonstration is completed must be
maintained. Alternative 4 requires that when treated in unknown
processes, biosolids be tested for pathogens at the time the
biosolids are used or disposed or, in certain situations, prepared
for use or disposal. Alternative 5 requires that biosolids be
treated in one of the Processes to Further Reduce Pathogens.
Alternative 6 requires that biosolids be treated in a process
equivalent to one of the Processes to Further Reduce Pathogens, as
determined by the permitting authority.
[0010] Class A pathogen biosolids must also possess a density of
fecal coliform of less than 1,000 most probable numbers (MPN) per
gram total solids (dry-weight basis) or a density of Salmonella sp.
bacteria of less than 3 MPN per 4 grams of total solids (dry-weight
basis). Either of these two requirements must be met at one of the
following times: when the biosolids are used or disposed; when the
biosolids are prepared for sale or give-away in a bag or other
container for land application; or when the biosolids or derived
materials are prepared to meet the requirements for Exceptional
Quality biosolids.
[0011] All biosolids applied to the land must meet the ceiling
concentration for pollutants, comprising ten heavy metal
pollutants: arsenic, cadmium, chromium, copper, lead, mercury,
molybdenum, nickel, selenium, and zinc. If a limit for any one of
these is exceeded, the biosolids cannot be applied to the land
without the incorporation of significant restrictions. Exceptional
Quality (EQ) is a term used by the USEPA Guide Part 503 Rule 7 to
characterize biosolids that meet low-pollutant and Class A pathogen
reduction (virtual absence of pathogens) limits and that have a
reduced level of degradable compounds that attract vectors.
[0012] Biosolids that are merely dried have several disadvantages
for agricultural use. Biosolids have a low fertilization value,
typically having nitrogen content of only about two to five
percent. Volume is large and costs per unit of nitrogen are high.
The heat-dried biosolids often have a disagreeable odor,
particularly when moist. Also, dried pellets have low density and
hardness and when blended with other commercial fertilizer
materials, the pellets may segregate, and disintegrate and may not
spread on the field uniformly with other more dense ingredients.
The disagreeable odor associated with the use of biosolids, unless
adequately treated, will continue to be present during further
processing of a nitrogen rich fertilizer product, and can continue
to be present in the final product. This complicates the placement
of suitable fertilizer processing plants to locations that are not
in close proximity to residential communities. Additionally, the
longer distance that biosolids must be transported adds to the cost
and logistics of disposing of this waste product. Another
disadvantage to current biosolids-enhanced fertilizers is that
bacterial action may continue when the material becomes moist, and
under storage conditions, the material's temperature may rise to
the point of auto-ignition. Hence, except for special markets that
value its organic content for soil amendment or filler in blended
fertilizer, there is relatively poor demand for the heat-dried
biosolids product. In many cases municipalities must pay freight
charges, or may offer other incentives for commercial growers to
use the material. However, this is frequently still more economical
than alternative disposal schemes.
[0013] The market value for agricultural fertilizers is principally
based on their nitrogen content. A need exists for a practical,
safe and economic method for increasing the nitrogen content of
biosolids to a level approaching that of commercial mineral
fertilizers, e.g., eight to twenty-two percent. If such a biosolids
fertilizer could be manufactured, then the overall value of the
biosolids product and demand for the product would likely increase.
Moreover, a properly manufactured biosolids fertilizer will have an
advantage in that much of its nitrogen will be of the slow release
type. Slow-release or controlled release fertilizer is one in which
the nutrient, e.g., nitrogen as in ammonium ions, phosphate and/or
sulfate, becomes available in the soil column at rates slower than
fast-available nutrients as from traditional fertilizers such as
urea, ammonium sulfate and diammonium phosphate. This slower action
and/or prolonged availability of the nutrient in the soil column is
very desirable and provides nutrients to the plant throughout the
plant growing cycle with the implication that less nitrogen needs
to be applied to the soil or crop thereby reducing the potential of
environmental contamination and reducing the cost of fertilizer
usage. Traditional inorganic manufactured slow release nitrogen
fertilizers have a price many times that of ordinary mineral
nitrogen fertilizers. Under the scenario of high nitrogen
biosolids-containing fertilizer production from their biosolids,
municipalities would enjoy public and regulatory support for their
biosolids disposition program. Such a program would ensure the
regular removal of their dewatered or dried biosolids, for example,
by recycling biosolids into a high nitrogen fertilizer which then
can be sold directly into the mature national fertilizer
distribution industry, thereby eliminating one of the major
problems traditionally associated with biosolids treatment
programs.
[0014] Prior attempts have been made to reach some of these
objectives. U.S. Pat. Nos. 3,942,970, 3,655,395, 3,939,280,
4,304,588, and 4,519,831 describe processes for converting sewage
biosolids to fertilizer. In each of these processes a
urea/formaldehyde condensation product is formed in situ with the
biosolids. Thus, the processes require the handling of
formaldehyde, a highly toxic lachrymator and suspected
cancer-causing agent.
[0015] Other processes require costly process equipment and/or
special conditions not readily incorporated in existing sewage
treatment facilities (see, Japanese Patent No. 58032638; French
Patent No. 2,757,504).
[0016] A simple method for increasing the nitrogen in bio solids
would be to blend commercial nitrogen fertilizer materials to the
wet biosolids prior to drying and pelletizing. There are only a few
high-nitrogen fertilizer materials that are economical for use in
agriculture. Examples include: ammonia (82 wt. percent N), urea (46
wt. percent N), and ammonium nitrate (33.54 wt. percent N). Ammonia
has high volatility and is subject to strict regulation of
discharges to the atmosphere. Urea is a solid that adsorbs moisture
quite readily and makes the sludge more difficult to dry. Urea is
also highly susceptible to breakdown to ammonia by the microbes and
enzymes in biosolids if they are not properly prepared, resulting
in nitrogen loss and an odor problem. Ammonium nitrate is a strong
oxidizer and can result in a potential explosion problem which has
all but eliminated this fertilizer from the commercial market after
2000. All of these fertilizers have high nitrogen content, but are
less than ideal for combining with biosolids absent special
processing.
[0017] Other references, such as European Patent No. 0143392,
Japanese Patent No. 9110570 A2, and "Granulation of Compost from
Sewage Sludge. V. Reduction of Ammonia Emission from Drying
Process", Hokkaidoritsu Kogyo Shikenjo Hokoku, 287, 85-89 (1988)
fail to disclose the use of acids with ammonium sulfate additions
and do not discuss the issue of corrosion of steel process
equipment under acid conditions.
[0018] Over the past thirty years, alkaline stabilization of
biosolids has been a standard and successful method of making
biosolids into beneficially useful materials that can be used
principally as soil-conditioning materials. Because these alkaline
stabilized biosolids products have high calcium carbonate
equivalencies, they have been produced and marketed as Agricultural
liming or Ag-lime materials, usually as a replacement for calcium
carbonate in farm soil management strategies. Because of this
usage, the value of these materials has been restricted to only a
few dollars per ton of product. However, transportation costs are
high in large part due to the significant water content of the
material. Amounts of water up to fifty percent render
transportation economically and geographically restricted to areas
close to the source of their treatment.
[0019] Thus, there is a long standing need for practical means of
increasing the economic value of sewage biosolids through
increasing its nitrogen content, and increasing the ability to be
spread as well as a need to treat these materials such that they
are converted into commodity fertilizers with physical and chemical
and nutrient properties such that they can command significant
value in the national and international commodity fertilizer
marketplace. A series of U.S. patents, U.S. Pat. Nos. 5,984,992;
6,159,263; 6,758,879 and 7,128,880 describe methods of production
of high nitrogen organically enhanced ammonium sulfate fertilizers
made with biosolids utilizing a pipe-cross reactor as originated by
the Tennessee Valley Authority. The pipe, tee and pipe-cross
reactor are defined by the IFDC in the Fertilizer Manual (1998), p
440 as: "the pipe reactor consists basically of a length of
corrosion-resistant pipe (about 5-15 m long) to which phosphoric
acid, ammonia and often water are simultaneously added to one end
through a piping configuration resembling a tee, thus the name `tee
reactor.`" The tee reactor was modified by TVA to also accept an
additional flow of sulfuric acid through another pipe inlet located
opposite the phosphoric acid inlet, giving the unit a "cross"
configuration and thus the name "pipe-cross reactor".
[0020] Both the IFDC Fertilizer Manual (1998) and the Fertilizer
Technical Data Book (2000) refer to the pipe-cross reactors.
Pipe-cross reactors deliver a concentrated mix to the granulator
shaping device and more efficiently evaporate undesired water from
the fertilizer mix than other devices, but these references
demonstrate a long-felt need for improvement, indicating that one
of the shortcomings of the pipe-cross reactor is scale formation
inside the pipe which can result in clogging.
[0021] The methodologies taught by this group of patents (U.S. Pat.
Nos. 5,984,992; 6,159,263; 6,758,879 and 7,128,880) are plagued by
problems related to the pluggage of these narrow (relative to their
length) "pipe-cross" reactor configurations, the very short
duration of reaction time in such "pipe-cross" reactors and the
difficulty of control of the reaction temperature and pressure and
retention time of the mix within such pipe-cross reactors. These
pipe-cross reactors are narrow in contrast to their length, e.g.,
up to six to eight inches in diameter and often fifteen feet in
length or longer. The plant practicing the manufacture of
organically-enhanced ammonium sulfate fertilizers often had to shut
down and disassemble the pipe-cross reactor either due to blockage
from biosolids buildup or from destructive over heating in such
reactors such that the commonly used Teflon.RTM. coating on the
interior-reaction side of the reactor was melted and ruined.
Further, the use of the pipe-cross reactor has the distinct
disadvantage of having very short reactor retention times (usually
less than twenty seconds) which is an advantage in the manufacture
of traditional fertilizers like ammonium sulfate but is a
disadvantage when coupled to the simultaneous processing of
biosolids. Such short processing time increases the probability of
untreated or non-homogenous mixing as the three material inputs
pass through this reactor. Also limiting is the lack of control
over the atmospheric pressure within such pipe-cross reactors since
these reactors have open-ended discharges usually directly into a
granulator. Related to but distinct from the lack of control of
internal pressures, pipe-cross reactors also have little to no
temperature control over the mix passing through the reactor.
[0022] U.S. Pat. No. 4,743,287 to Robinson describes a method to
use two reaction vessels in sequence to incorporate organic
biosolids into nitrogen fertilizers of low or medium nitrogen
concentration (a range of four weight-percent nitrogen to a maximum
of nitrogen concentration of ten weight-percent). Robinson uses his
first reaction vessel to achieve very low pH values of the mixture
(pH 0.2 to 1.5) to achieve hydrolysis of molecules present and to
prepare the mix for reaction in a second reaction vessel. Robinson
does indicate that a single reactor can be used, but only in a
batch configuration and not in a continuous flow manufacturing
method. Robinson also indicates that the acid and ammonia may not
be injected in any order, but must be injected in sequence. This
patent describes the reaction vessels capable of achieving high
pressures (30 psig) with relatively long retention times as
compared to the pipe-cross reactors. However, Robinson fails to
meet the need for a novel and practical continuous flow method of
manufacturing high nitrogen (greater than 8 wt. percent nitrogen)
and biosolids-containing fertilizer products under the advantages
of defined temperatures, pressures and reaction retention times.
Thus, an urgent need exists for an effective, efficient, and
economical process for treating biosolids.
SUMMARY OF THE INVENTION
[0023] The present invention overcomes the problems and
disadvantages associated with current strategies and designs, and
provides new tools and methods for the manufacture of
fertilizers.
[0024] One embodiment of the invention is directed to methods for
manufacture of a fertilizer comprising: providing an organic
material that preferably contains biosolids, wherein the organic
material has a solids content of at least ten percent; optionally
adding an odor control agent to the organic material to create a
mixture; adding an acid to the mixture under a first pressure and
elevated temperature for a first period of time forming a liquefied
mixture; adding ammonia to the liquefied mixture under a second
pressure and elevated temperature for a second period of time; and
processing the liquefied mixture to form the fertilizer. The phrase
organic material includes all biosolids, but is not limited to
biosolids such as organic biosolids, biosolids containing
microorganisms, municipal biosolids or heat-dried biosolids, and
also includes pharmaceutical and laboratory processing and
fermentation wastes, farm and agricultural wastes, decayed and
digested organic materials, harvested plants including farmed crop
materials such as roughage and silage of corn and soybean plants as
well as wheat, rice and barley plants, algae and cyanobacteria that
may be harvested from ponds and other bodies of water, bacteria,
mold and fungi, industrial wastes and their by-products, microbial,
chemical and enzymatic digests of organic products, plant and
animal foods, food stuffs, and byproducts, recycled fertilizers,
and all combinations thereof. An element of the invention is that
the organic material that contains plastic and hair and similar
material does not need to be removed prior to processing.
Preferably, the organic material is dewatered or hydrated to a
solids content of between 15 and 40 percent, more preferably the
organic material has a percent dryness of 22 percent or less. Also,
a portion of the organic material may be dewatered to a dryness
greater than 70 or 85 percent, and blended with the remaining
portion of the organic material to achieve a desired percent
dryness. Preferably, the organic material is hydrated with process
water recovered from one or more steps of the method.
[0025] Optionally, odor control agents may be added to the organic
material. Preferred odor control agents include, but are not
limited to one or more of calcium ferrate, sodium ferrate,
potassium ferrate, ferrous sulfate heptahydrate, rozenite,
melanterite, ferric chloride, ferrous sulfate, ferrous sulfate
monohydrate, hydrogen peroxide, ozone and salts, derivatives and
combinations thereof, as well as various salts thereof. Preferably,
the mixture of the organic material with the odor control agent
forms a thixotropic mixture and the mixture is heated prior to the
addition of acid. Also preferably, heating is performed in a first
pressure vessel and the first pressure is maintained at between 20
and 60 psig, the first temperature is between 66.degree. C.
(150.degree. F.) and 127.degree. C. (260.degree. F.), and the first
period of time is between 3 minutes and 30 minutes. More
preferably, the first temperature may be between 93.degree. C.
(200.degree. F.) and 121.degree. C. (250.degree. F.) and the first
period of time may be between 5 minutes and 10 minutes. Preferably
the viscosity of the acidified and heated mixture is about 4,000 cP
or less. The acid added to the mixture is preferably a phosphoric
acid, a sulfuric acid, or a combination thereof. After
acidification, the liquefied mixture is transferred to a second
pressure vessel and, preferably, ammonia is heated under pressure
to form a gas prior to being added to the liquefied mixture. The
preferred second temperature is between 121.degree. C. (250.degree.
F.) and 199.degree. C. (390.degree. F.), the preferred second
period of time is between 1 minute and 30 minutes, and the
preferred pressure within the second pressure vessel is maintained
at between 50 and 200 psig. The viscosity of the ammoniated mixture
is preferably about 1,000 cP or less. Processing of liquefied
mixture comprises forming the usable fertilizer. Preferably, the
processing comprises drying the combination to a solids content of
greater than 92 percent, or more preferably to a solids content is
at least 98 percent. One or more hardening agents may be added
during processing such as, for example, ligno-sulfonate, molasses,
alum or a combination thereof. Preferably processing is performed
in a granulator to form granules and the granules are sized and
granules of between 0.5 and 4 mm selected. Preferably, granules of
greater than 4 mm are further crushed, and combined with granules
of less than 0.5 mm and both are added during processing. An
element of the invention is that each step of the method can be
performed in a continuous process without interruption, although
batch processing is also possible. The processes of the invention
preferably also comprise a dust control system that collects and
recycles dust material created from the processing.
[0026] Another embodiment of the invention is directed to
fertilizer manufactured by the methods of the invention. Fertilizer
will typically contain hydrolyzed polymers of one or more of
plastics, pharmaceutical compounds, antibiotics, hormones,
hormone-like molecules, biologically active compounds,
macromolecules, carbohydrates, nucleic acids, fats, lipids,
proteins, and microorganisms that are present in the biosolids.
Preferably the hydrolyzed polymers are amino acids, most of which
are not destroyed during the method of processing, that supplement
and substantially increase the value of the fertilizer. Preferably,
fertilizer of the invention has a nitrogen content of between 6 and
20 percent, a phosphate content of between 0 and 10 percent, a
potassium content of between 0 and 5 percent, a sulfur content of
between 10 and 30 percent, an iron content of between 0 and 10
percent, and an organic content of between 5 and 30 percent. Also
preferably, the fertilizer has no or almost no unpleasant or
disagreeable odors.
[0027] Another embodiment of the invention is directed to processes
for manufacture of a fertilizer with a predetermined content of one
or more of nitrogen, phosphate and potassium comprising: providing
an organic material containing biosolids wherein the organic
material has a solids content of at least ten percent; optionally
adding an odor control agent to the organic material to create a
mixture; heating the mixture under a first pressure to a first
temperature for a first period of time; adding an amount of a
predetermined acid to the heated mixture, thereby creating an
exothermic reaction and forming a liquefied mixture; adding a
predetermined amount of ammonia to the liquefied mixture under a
second pressure and heating the mixture to a second temperature for
second period of time, wherein the amount of ammonia added is
determined from the composition of the organic material; and
processing the liquefied mixture to form the fertilizer with a
predetermined content of one or more of nitrogen, phosphate and
potassium. The process of the invention may optionally further
comprise adding one or more plant nutrients to during processing.
Such plant nutrients that can be added include, but are not limited
to one or more of urea, ammonium nitrate, ammonium sulfate,
monoammonium phosphate, diammonium phosphate, urea ammonium
nitrate, liquid urea, potash, iron oxide, soluble iron, chelated
iron and combinations thereof. The process preferably further
comprises adding and one or more hardening agents during processing
such as, for example, ferric oxides, alum attapulgite clay,
industrial molasses, lignin, ligno sulfonate, urea formaldehyde
polymerizer and combinations thereof.
[0028] Another embodiment of the invention is directed to systems
for the manufacture of a fertilizer comprising: a mixer that blends
biosolids with an odor control agent; a first reaction or pressure
vessel wherein the blended biosolids are mixed with an acid and
heated to a first predetermined temperature and pressurized to a
first predetermined pressure for a period of time forming a liquid;
a second reaction or pressure vessel wherein the liquid is mixed
with ammonia from an ammonia source and heated to a second
predetermined temperature and pressurized to a second predetermined
pressure for a second period of time; and a granulator wherein the
ammoniated liquid is mixed with preformed granules and heated to
form dried granules of the fertilizer. Preferably the ammonia
source is liquefied or gaseous ammonia under pressure and the first
and second reaction or pressure vessels each contain an agitator.
The systems may also include a screening process to select product
sized fertilizer granules, and one or more a cooling and coating
apparatus to reduce temperature and control dust prior to storage.
Optionally, the cooler may include an ozone generator that provides
ozone to the cooling fertilizer to eliminate or at least
substantially reduce disagreeable odors. Preferably, systems also
comprise a conveyer for transporting biosolids to the mixer and
another conveyer for transporting the blended biosolids to the
first reaction or pressure vessel; a pressurized piping system that
transports acidified biosolids from the first reaction or pressure
vessel to the second reaction or pressure vessel, ammonia into the
second reaction or pressure vessel; and disperses the ammoniated
liquid to the granulator. Preferred systems further comprise one or
more screens for selecting granules of a predetermined size and a
rotary cooler for cooling and polishing the sized granules, and
both a dust control apparatus that collects and recycles dust from
the granulator and a water recovery system whereby water extracted
from biosolids during processing is recovered and recycled. In
certain embodiments, the first and/or second reaction or pressure
vessel may be a pipe-cross reactor, or both reaction or pressure
vessels are pipe-cross reactors. The process may be performed as a
continuous or batch process.
[0029] Another embodiment of the invention is directed to methods
for manufacture of a product comprising: providing an organic
material wherein the organic material has a solids content of at
least ten percent; adding an acid to the organic material under a
first pressure and elevated temperature for a first period of time
forming a liquefied mixture; adding ammonia to the liquefied
mixture under a second pressure and elevated temperature for a
second period of time; and processing the liquefied mixture to form
the fertilizer. Preferably the organic material is plant or
bacterial material and, also preferably, the plant or bacterial
material is algae, bacteria, fungi or a combination thereof.
Preferably there are toxic materials present in the organic
materials that are hydrolyzed or otherwise rendered nontoxic or
inactivated by the process of the invention. Preferably the first
pressure is between 20 and 60 psig, the elevated temperature is
between 66.degree. C. (150.degree. F.) and 127.degree. C.
(260.degree. F.) and the first period of time is between 3 minutes
and 30 minutes. Also preferably, the second pressure and elevated
temperature for a second period of time are, respectively, between
50 and 200 psig and between 121.degree. C. (250.degree. F.) and
199.degree. C. (390.degree. F.), between 1 minute and 30 minutes.
Preferably the product is a fertilizer.
[0030] Another embodiment of the invention is directed to
fertilizer manufactured by the methods of the invention.
Preferably, fertilizers of the invention have both fast and slow
nitrogen release profiles so that a percentage of available
nitrogen is released to the soil upon application of the
fertilizer, preferably from 10 percent to 70 percent, and a second,
slower release representing about 30 percent to 90 percent of the
available nitrogen content of the fertilizer releases into the soil
over a period of week and months. Preferably, nitrogen release is
timed to match the needs of the growing crops or plants.
[0031] Other embodiments and advantages of the invention are set
forth in part in the description, which follows, and in part, may
be obvious from this description, or may be learned from the
practice of the invention.
DESCRIPTION OF THE FIGURES
[0032] FIG. 1A is directed to portions of the Biosolid Fertilizer
Plant Flow Chart of one embodiment of the Invention.
[0033] FIG. 1B is directed to portions of the Biosolid Fertilizer
Plant Flow Chart of one embodiment of the Invention.
[0034] FIG. 1C is directed to portions of the Biosolid Fertilizer
Plant Flow Chart of one embodiment of the Invention.
[0035] FIG. 2A is directed to portions of the Biosolid Fertilizer
Plant Flow Chart of another embodiment of the Invention.
[0036] FIG. 2B is directed to portions of the Biosolid Fertilizer
Plant Flow Chart of another embodiment of the Invention.
[0037] FIG. 2C is directed to portions of the Biosolid Fertilizer
Plant Flow Chart of another embodiment of the Invention.
[0038] FIG. 3. Schematic of a modified Ammonium Sulfate
Process.
[0039] FIG. 4. Physical and chemical characteristics of organically
modified ammonium sulfate fertilizer of one embodiment of the
invention.
[0040] FIG. 5. Nitrogen release curve of ammonium sulfate
fertilized plants showing percent nitrogen released into soil over
number of weeks.
[0041] FIG. 6. Nitrogen release curve showing percent nitrogen
released into soil over number of days for ammonium sulfate (AS),
organically-modified ammonium sulfate of the invention (VITAG), and
conventional biomass (MILORGANITE).
[0042] FIG. 7. Academic nitrogen release curve of plants fertilized
with ammonium sulfate, organically-modified ammonium sulfate of the
invention, and biosolids showing percent nitrogen released into
soil over number of weeks.
DESCRIPTION OF THE INVENTION
[0043] All countries and population regions around the world create
waste in the form of organic materials. The phrase organic material
includes, but is not limited to biosolids such as organic
biosolids, biosolids containing microorganisms, municipal biosolids
and heat-dried biosolids, and also includes pharmaceutical and
laboratory processing and fermentation wastes, farm and
agricultural wastes, decayed and digested organic materials,
harvested plant and plant-like materials such as algae including
blue/green algae, bacteria including blue/green bacteria,
cyanobacteria (e.g., blue/green, rust, black), mold and fungi,
industrial wastes and their by-products, microbial, chemical and
enzymatic digests of organic products, plant and animal foods, food
stuffs, and byproducts, animal manures, digested and processed
animal manures, recycled fertilizers, and all combinations thereof.
Disposal of organic waste materials pose a major problem as well as
expense to all communities. Traditional disposal methods involve
burial, burial at sea or incineration. Each of these options
compounds the problem by creating untenable amounts of pollution
that foul the community as well as the planet. New techniques have
been developed that involve heat treatment to inactivate
microorganisms and other potentially contaminants that can result
in a product that can be as a low value fertilizer. Although these
techniques are ecologically sound, they have not caught on because,
in large part, the product is of such low value that there is
little to no commercial incentive for communities to switch from
the traditional bury and burn philosophy, and no funds that allow
for the creation of safe processing facilities.
[0044] It has been surprisingly discovered that high-value
fertilizer can be efficiently manufactured from organic materials,
including but not limited to, raw and semi-processed biosolids,
agricultural materials and industrial wastes. The process of the
invention destroys not only all potentially harmful microorganisms,
but hydrolyzes many polymers including forms of biopolymers (e.g.,
DNA, proteins, carbohydrates, toxins, antibiotics, hormones, etc.),
forms of composite materials, and even forms of plastics. The
resulting fertilizer product is of high value and also contains the
hydrolyzed monomers (e.g. amino acids, sugars, etc.) that are
beneficial and desirable for a fertilizer. The process of the
invention also allows for the production of fertilizer with
pre-selected amounts of each of the components of the fertilizer
including, but not limited to, the concentrations of nitrogen,
phosphorous, potassium, sulfur, iron and organics.
[0045] One embodiment of the invention is directed to methods for
the manufacture of a fertilizer. A schematic of the general process
of the invention is depicted by FIG. 3. The method comprises
providing an organic material which may contain biosolids or
another organic material to which, optionally, is added an odor
control agent, that itself can be utilized as an important plant
nutrient in the final fertilizer product, to reduce or eliminate
odors that may be present from the organic material or other
components of the starting materials. The resulting mixture, which
may contain added water recycled from other steps of the method, is
thoroughly mixed and heated to a predetermined temperature for a
period of time prior to commencing the critical acid/base reactions
that occur in a reaction or hydrolysis vessel. To this heated
material is added an acid that reacts exothermically with the
organic material and increases both temperature and pressure.
During this time, preferably two to ten minutes, the components are
mostly or entirely liquefied. To the heated liquefied material,
which optionally may be transferred to a second pressure vessel, is
added ammonia, which is preferably also liquefied or vaporized and
also under pressure, and the subsequent reaction with the acid
component of the mixture serves to further increase temperature and
pressure. The ammoniated and liquefied biosolids are maintained for
a short period of time under these conditions, preferably two to
ten minutes, and then processed, preferably into granules of
fertilizer.
[0046] The ammoniation reaction may be carried out to completion
whereby all or nearly all of the acid is reacted such that little
to no residual acid remains. The combination of nearly all of the
acid produces a salt or a salt melt (a partially ammoniated mix)
(e.g. with sulfuric acid the salt produced is ammonium sulfate).
Preferably, upon ammoniation salt to melt ratios are about 20/80,
about 25/75, about 30/70, about 35/65, about 40/60, about 45/55,
about 50/50, about 55/45, about 60/40, about 65/35, about 70/30,
about 75/25, and about 80/20. Salt formation may be determined and
in real time by the measurement of the pH of the mixture. Preferred
pH values are between 6.2 and pH 7.0. Alternatively, it is
sometimes preferable to partially ammoniate the acid mixture in the
reactor and complete the ammoniation in a second pugmill or in the
granulation process.
[0047] An advantage of this invention is that, because the organic
materials are liquefied, the liquid can be more easily transported
as needed through pipes preferably using pressure differentials as
compared with any solid, semisolid or thixotropic material. The
liquefied organic materials can also be more evenly applied to
acceptor material in the granulator thereby permitting the
formation of a more evenly formed spherically-shaped granule.
Biosolids are preferably entirely liquefied, although mostly
liquefied is typically sufficient. Preferably the liquid exhibits a
characteristic readiness to flow, little or no tendency to
disperse, and relatively high incompressibility.
[0048] Viscosity of the starting organic material is typically in
excess of 100,000 cP and typically 150,000 cP at ambient
temperature and does not change significantly even at elevated
temperatures typical in a processing facility. For comparative
purposes, at about room temperatures, molasses has a viscosity of
about 5,000 to 10,000 cP, honey has a viscosity of about 2,000 to
10,000 cP, chocolate syrup has a viscosity of about 900 to 1,150
cP, and olive oil has a viscosity of about 81 cP. With the addition
of acid and heat according to invention, viscosity of the organic
material decreases to a range of from about 1,000 to 10,000 cP, and
preferably to less than 4,000 cP, more preferably to less than
3,000 cP, more preferably to less than 2,000 cP, and more
preferably to less than 1,000 cP. With the addition of ammonia and
the added temperature increase from the resulting exothermic
reaction, viscosity decreases to a range of 500 to 4,000 cP, and
preferably to 2,000 cP or less, more preferably to 1,000 cP or
less, and more preferably to 750 cP or less, and more preferably to
500 cP or less. Also, problems typically associate with solid
debris that is normally present in organic material such as
biosolids, with debris such as plastic and hair, are eliminated as
all such material is hydrolyzed as well.
[0049] The low viscosity material of the invention has a
substantially decreased energy requirement for transportation and
processing as compared with conventional materials. No biological
or organic solid material remains, so problems and inefficiencies
commonly associated with solid debris clogging or otherwise
blocking transport from one area to another and thereby requiring
shutting down the system for maintenance are eliminated. No solids
or semi-solids are present that would otherwise increase wear and
tear on equipment and thus, shorten equipment life. Further,
organic solid materials including, for example, plastic and hair,
well known to cause blockages in conventional processing, are
completely broken down and hydrolyzed to their monomer components.
The acid reaction hydrolyzes many polymers that may be present
including plastics, hair, and biologically active compounds
(whether naturally present or artificially created), and breaks
down and destroys many and nearly all and preferably all
macromolecules and microorganisms that may be present. This
increases the safety to process workers and further simplifies and
increases the efficiency of any cleaning or maintenance of the
system that may be required periodically. This hydrolysis further
increases the safety in the use of the resultant fertilizer product
in comparison to other traditional organics-containing fertilizer
products such as those made in biosolids alkaline-stabilization
processes.
[0050] Another advantage of the invention is that, because the
process can be easily contained, the need for dust and odor control
apparatus is minimized. The processing steps are closed and under
negative pressure and no steps are performed in open or areas
exposed to the environment or the environment of the facility. Odor
control agents are preferably added initially, but could optionally
as easily be added at any step in the process. Alternatively, or in
addition to other odor control processing, the granules may be
exposed to ozone during formation and/or cooling. Ozone will
substantially reduce or eliminate disagreeable odors of the
fertilizer. Thus the invention is a major improvement as compared
to conventional fertilizer manufacturing practices in which a large
manufacturing facility is located as far away from communities as
possible thereby requiring that input materials be shipped over
long distances to operate the plant. A good example of this problem
was the biosolids conversion-to-fertilizer plant located in Helena,
Ark. which practiced the manufacturing processes taught in U.S.
Pat. Nos. 5,984,992; 6,159,263; 6,758,879; and 7,128,880, and
utilized biosolids that were transported all the way from New York
City.
[0051] Another advantage of the invention is that, because acid and
ammonia are added in a controlled manner, the final components of
the fertilizer can be predetermined. The exact amount of nitrogen
in the final product can be regulated based on the amount of the
starting materials including the biosolids, acid, base, water, and
any other components. Similarly, the exact amount of sulfur, iron,
phosphate, potassium and even organic matter can also be regulated
or, if desired, eliminated from the final product producing a
custom-made fertilizer product. Many crops that require
fertilization are grown in areas known to be high in phosphate,
sulfur, potassium or other elements. Fertilizing with conventional
fertilizers, although needed, typically exacerbates the
contamination. Fertilizers produced by the methods of the present
invention would not only overcome such problems, but could be
tailored for use in conjunction with a specific type of soil or
specific need of a select type of crop. In addition, the process of
the invention allows for supplementation of the fertilizer during
processing with additional ingredients.
[0052] Another advantage of the invention is that it is easily
performed in large scale, with continuous processing and under
automation. No significant retention times are required, thus no
delays, so that processing continues from start to finish without
interruption as can be required when material is required to
incubate for days as is common for some types of conventional
biosolids processing as in composting or alkaline stabilization
processes. Also, the process is not dependent on a particular
amount of material. The process of the invention is scalable to any
amount of organic material. This is highly preferred at least
because most municipal regions vary in size and thus, the amounts
of organics such as biosolids produced per day vary widely. Also,
amounts are expected to also vary over time. Further, each step of
the process can be performed under complete automation including
accounting for necessary variation per day and over time.
[0053] Another advantage of the invention is that it allows for
co-location of the facilities for processing organic materials such
as biosolids with the treatment plants. Biosolids can be then taken
directly from waste water treatment plants to processing thereby
minimizing transport and potential spillage of potentially harmful
compounds. Another preferred embodiment is to locate close enough
to the wastewater treatment plant to be connected by a screw or
belt conveyor or a biosolids pumping system. Alternatively, another
preferred embodiment is to locate adjacent to the wastewater plant.
The goal of the present invention is to place the processing plant
as close to the wastewater plant as possible. Thus the present
invention eliminates the cost of transportation by locating the
physical equipment necessary to perform the manufacturing process
adjacent or close to the source of the biosolids such as municipal
wastewater treatment plants. Manufacturing plants of the invention
preferably allow for adjacent storage facilities. Again, by being
adjacent, transportation logistics are simplified or eliminated
thereby reducing transportation costs of the product as well as the
transportation costs of input organics such as biosolids. Also, the
processes of the invention have the advantage that they may be
interfaced with other production facilities. Those facilities may
be associated with an unrelated commercial enterprise such as, for
example, nylon or steel production. In these two industries hot
ammonium sulfate is created as a by-product to the manufacture of
product. Further and more commonly, co-locating near a commercial
enterprise that creates excess heat, as in a furnace, or kiln,
would advantageously permit the use of this excess heat by the
present invention as in the replacement of the need for fossil
fuels such as natural gas or by the co-generation of electricity by
utilization of said excess heat. By co-locating a processing
facility of the invention at these types of sites, the otherwise
unwanted by-products such as ammonium sulfate need not be carted
away, but can be directly utilized in the manufacture of fertilizer
according to the present invention.
[0054] Another advantage of the invention is that because the
process minimizes the amount of water and power (e.g. electrical)
needed, and amount of waste byproducts formed, as compared to
conventional processing, manufacturing can be sized to service the
needs of the size of the particular community in which the plant is
located. This tailoring design allows for a biosolids
processing/fertilizer manufacturing plant that can process smaller
amounts of biosolids (e.g., less than 3 tons per hour of dewatered
biosolids) or scaled up for larger plants (e.g., up to 10 to 12
tons per hour or more). In a preferred embodiment the optimal size
is between 6 and 8 tons per hour when the biosolids are
standardized to a percent solids of 25. The amount of biosolids
processed per hour does depend upon the percent solids of the
biosolids. As the biosolids increase in moisture the amount of
biosolids that may be processed per hour increases proportionally.
This sizing feature reduces costs, allows for standardization with
interchangeable equipment and increases the efficiency of the
operational logistics as well as decreases overall liability.
[0055] Organic materials that can be processed according to the
invention include, but are not limited to biosolids. Types of
biosolids include municipal biosolids, domestic septage, farm and
agricultural wastes, animal manures, digested and processed animal
manures, recycled biosolid fertilizers, organic biosolids,
biosolids containing microorganisms, and heat-dried biosolids.
Other organic materials that can be processed according to the
method of the invention include, but are not limited to
pharmaceutical and laboratory processing and fermentation wastes,
organic industrial wastes, microbial materials, decayed and
digested organic materials, farm and agricultural wastes, harvested
plant materials such as algae including blue/green algae, seaweed
and other aquatic plants and water-borne organic detritus, bacteria
including blue/green bacteria and cyanobacteria (e.g., blue/green,
rust, black), slime, insects and insect biomass (e.g., body parts,
manure), mold and fungi, industrial wastes and their by-products,
microbial, chemical and enzymatic digests of organic products,
foods, food stuffs and food byproducts, and combinations thereof.
In addition to conventional biosolids, most all organic materials
can be processed by the methods of the invention including spoiled
or otherwise rotted food stuffs such as, but not limited to meats,
fish and agricultural products as well as plastics, and
carbon-containing household trash and recyclables.
[0056] Another advantage of the invention is that organic
materials, and even certain non-organic materials, that are
otherwise difficult to dispose can be processed according to the
invention as a method of turning into a useful product what would
otherwise be waste material occupying space in a landfill or the
ocean. By way of non-limiting example, algae is skimmed from the
surface or otherwise collected from bodies of water for aesthetic
purposes as well as for the general health of the plants and
animals that habitat the environment. Often this algae may be
contaminated with natural toxins or toxic compounds absorbed or
metabolized and concentrated within the algae from the environment.
By processing the algae according to the methods of the invention,
the algae can be converted to fertilizer and, importantly, the
toxins destroyed or otherwise inactivated. In addition, algae or
other plants or bacteria may be intentionally grown in or on a
contaminated area and harvested to be processed according to the
invention. In addition, as toxic contamination is a matter of
concentration, the materials generated from the processes of the
invention can be added to other processed materials and
sufficiently diluted so as not to pose a hazard. This process of
land or water reclamation can be performed with a variety of
plants, bacteria and insects with the organisms collected,
processed according to the invention and rendered non-toxic or
otherwise harmless. Accordingly, the process of the invention can
be applied to treated or untreated soil, humus and most any biomass
including cellular components, sedimentary organic matter, and
biotic materials.
[0057] The organic material is preferably dewatered or hydrated to
a solids content of between 10 and 40 percent, more preferably
between 20 and 30 percent, and more preferably between 22 and 25
percent. The optimal solids content of a particular organic
material can also be empirically or experimentally determined.
Organic material received for processing according to the invention
will typically have lower solids content than the optimal level.
Preferably, the organic material of insufficient solids content can
be adjusted to the desired concentration through blending/mixing
with `dry` organic materials with a solids concentration of 70 to
95 percent and preferably 85 to 92 percent. The `dry` organic
materials may be available through third party sources or may be
produced with the available organic material through heat drying.
Heat drying processes include heated screw conveyors, disc dryers,
rotary dryers, paddle mixer/dryers, fluid bed dryers and other
commercially available processes/equipment. The dried organic
materials and the organic material of insufficient solids
concentration will be mixed in a mixing vessel to reach the ideal
solids content as determined empirically or experimentally. The
mixing vessel may be a pugmill, a mixing screw conveyor, a
multishaft mixer, a ribbon paddle blender, a high shear mixer or
other commercial high viscosity slurry mixer. Less preferably, the
organic material of insufficient solids content can be adjusted to
the desired concentration by heating the material to remove water
as necessary to attain the desired concentration. This can also be
done in the same heat drying equipment listed above. Organic
materials received for processing may need hydration and, when
necessary, additional water is preferably added from water
collected during other steps of processing. This use of recycled
water further adds to both the efficiency and beneficial economics
of the invention.
[0058] If necessary during the intake processing, the organic
material can be conditioned by injection of steam, water, and/or
heat (e.g. made thixotropic) to enable or enhance flow or movement.
In these initial steps, the organic material can be blended with
chemical additives such as oxidizing agents, for the initial odor
control and to prepare the biosolids for reaction in the pressure
vessel. For example, biosolids may be infused with black or
agricultural grad phosphoric acid to minimize odors. In this
example, the phosphoric acid added here will alter the final
concentration of phosphate in the fertilizer product. The amount of
phosphate added to the product in this step can be as little as 0.5
percent and as much as 6 percent. In addition to odor minimization,
the phosphoric acid adds a valuable nutrient component to the
product fertilizer.
[0059] Preferably the odor control agent is added to the initial
organic material to be processed, although one or more odor control
agents can be added at any time during processing including during
granule formation and cooling. Preferred odor control agents
include, but are not limited to calcium ferrate, sodium ferrate,
potassium ferrate, ferrous sulfate heptahydrate, rozenite,
melanterite, ferric chloride, ferrous sulfate, ferrous sulfate
monohydrate, hydrogen peroxide, and/or ozone as well as various
other salts, derivatives and combinations thereof. The amount and
type of odor control agent can be determined empirically by one of
ordinary skill in the art, but typical amounts range from 0.01
percent by weight of the mix or of the granules, to up to 6 percent
of the mix or granules, and is preferably about 0.05%, 0.1%, 0.25%,
0.5%, 0.75%, 1.0%, 1.5%, or 2.0%.
[0060] The organic material, odor control agent and possibly
recycle water are delivered to a mixing vessel where they are
thoroughly mixed and may form a thixotropic paste that is pumped or
easily transported. The mixing vessel may be a pug mill, a mixing
screw conveyor, a multishaft mixer, a ribbon paddle blender, a high
shear mixer or other commercial high viscosity slurry mixer.
Pug-mills, blenders and mixers are mixing chambers having
blade-shaped blending elements mounted on a powerfully driven shaft
or shafts that rotate at a variable but controlled speed which
divide, mix, back-mix and re-divide the materials to be blended
multiple times a second to yield a thorough, uniform blend with
reliable consistency.
[0061] Alternatively, the mixing vessel to reach solids
concentration and the mixing vessel for the conditioning with
recycle water, phosphoric acid, odor control agents or other
additives may be combined in a single mixer of adequate size to
give desired mixing energy and time.
[0062] This mixture is heated preferably by indirect heat such as a
heated screw conveyor, paddle mixer or disc dryer or direct heat
such as steam injection, to a temperature required for proper
reaction in the next acidification phase of the process. The
required temperature is determined by the type and concentration of
the acid used as well as the type and concentration of the organic
materials mixture. Heating the mixture preferably involves
continuous mixing or agitation of the mixture within the mixing
vessel and possibly heating of the vessel itself. Accordingly, to
achieve a desired temperature of the mix, more or less heat may be
required depending in part of the material composition of the
vessel. Preferably heating is performed for a retention period of
time that is equivalent to the time required to achieve the desired
temperature or the mixture may be maintained for longer periods of
time. Preferred periods of time, which includes heating time, are
between 1 and 30 minutes, more preferably between 3 and 15 minutes,
more preferably between 5 and 10 minutes (or any combination of
these ranges). Also, heating times may also be dependent on the
amount of mixture being heated. Preferred is a heating time that is
about equivalent to the time it takes to achieve the desired
temperature. Less preferably, heating may also be achieved through
direct injection of steam or heated gases in a mixing vessel or
piping system.
[0063] To the heated mixture is added acid, in the preferred
embodiment at the inlet of the first pressure vessel, creating an
exothermic reaction, which thereby causes additional heating. The
acid is added to the mixture by direct injection into a pressure
vessel or injection at the vessel inlet. In the pressure vessel the
mixture is agitated or otherwise continuously mixed. The acid is at
a very low pH and preferably in the range of pH negative 4.0 to pH
positive 2.0. As is known to those skilled in the art, with a very
strong aqueous acid there are too few water molecules to
disassociate the acid completely. As a consequence, the true pH is
much lower than an actual measurement. A negative pH indicates that
the pH calculation would be a negative log of the molarity where
the molarity of hydrogen ions is greater than 1. Preferred pH
values for acids utilized are, for example, pH of 2.0 or less, pH
of 1.0 or less, pH of 0.8 or less, pH of negative 1.0 or less, pH
of negative 2.0 or less. Preferred acids include, but are not
limited to hydrochloric acid, boric acid, hypochlorous acid,
perchloric acid, carbonic acid, phosphoric acid, sulfuric acid,
nitric acid, hydrofluoric acid, carboxylic acid, and derivatives,
mixtures, and combinations thereof. The amount and type of acid
added is determined by one of ordinary skill in the art from the
amount of organic materials being treated and/or the desired
result, which includes but is not limited to one or more of,
achieving a predetermined temperature or pressure or liquefying the
mixture. In part because the organic materials are liquefied, there
is little to no build-up of calcium silicate, insoluble phosphate
compounds or other insoluble compounds in pipes, a typical problem
with conventional biosolids processing facilities. Addition of the
acid causes an exothermic reaction that heats and increases the
pressure of the container. This pressure which upon commencement of
the reaction is at ambient may in fact be maintained at ambient or
a desired pressure throughout the acidification process by
monitored or controlled venting. Alternatively, the pressure may be
allowed to increase with increasing temperature due to the
exothermic heat of dilution reaction. Such pressures may reach an
upper range of 60 psig by controlling venting or in the absence of
venting.
[0064] Temperature of the mixture increases, preferably to or above
66.degree. C. (150.degree. F.) such as for example to or above
82.degree. C. (180.degree. F.) or 93.degree. C. (200.degree. F.),
and more preferably to or above 104.degree. C. (220.degree. F.),
110.degree. C. (230.degree. F.), 116.degree. C. (240.degree. F.),
121.degree. C. (250.degree. F.), 127.degree. C. (260.degree. F.),
132.degree. C. (270.degree. F.), 137.degree. C. (280.degree. F.),
143.degree. C. (290.degree. F.), 149.degree. C. (300.degree. F.),
163.degree. C. (325.degree. F.) or to or above 177.degree. C.
(350.degree. F.). This acidification may be carried out without
pressure in the reactor by permitting release of vessel air during
acidification, however in the preferred embodiment to facilitate
the transfer of the acidified mix into the second vessel the
pressure in the first or acidification vessel will be maintained
above the pressure achieved the second vessel. The acidification
process is carried out for a retention time of between 3 minutes
and 30 minutes with a preferred time of between 4 minutes and 8
minutes.
[0065] Subsequent addition of the ammonia base, preferably in a
second pressure vessel, further affects the temperature of the mix,
preferably raising the temperature to at or above 132.degree. C.
(270.degree. F.) such as 138.degree. C. (280.degree. F.) or
143.degree. C. (290.degree. F.), more preferably to at or above
149.degree. C. (300.degree. F.), more preferably to at or above
154.degree. C. (310.degree. F.), 160.degree. C. (320.degree. F.),
166.degree. C. (330.degree. F.) or 171.degree. C. (340.degree. F.),
and more preferably to at or above 177.degree. C. (350.degree. F.)
such as for example to at or above 182.degree. C. (360.degree. F.),
188.degree. C. (370.degree. F.), 191.degree. C. (375.degree. F.),
193.degree. C. (380.degree. F.), 199.degree. C. (390.degree. F.),
204.degree. C. (400.degree. F.) 210.degree. C. (410.degree. F.),
216.degree. C. (420.degree. F.), 221.degree. C. (430.degree. F.),
227.degree. C. (440.degree. F.) or 232.degree. C. (450.degree. F.).
Preferably heating is performed for a retention period of time that
is equivalent to the time required to achieve the desired
temperature and allow completion of reactions. Preferred periods of
reaction time, which may include exothermic heating time, are
between 1 and 30 minutes, more preferably between 3 and 15 minutes,
more preferably between 5 and 10 minutes, or any combinations of
these ranges. Also, reacting times may also be dependent on the
constituents and/or makeup of mixture being reacted and/or the
amount and/or type of acid added. Reactions take place in closed
container vessels, and pressure in the headspace of the container
vessel increases as well. Pressures can again be regulated with
pressure relief valves and are preferably maintained between 5 psig
and 250 psig, more preferably between 30 psig and 150 psig, and
more preferably between 40 and 100 psig. Preferred pressures
include, but are not limited to 5, 10, 20, 30, 40, 50, 60, 70, 75,
80, 90, 100, 110, 120, 125, 130, 140, 150, 160, 170, 175, 180, 190,
200, 210, 220, 225, 230, 240 and 250 psig.
[0066] After reaction of the acid at the desired time, temperature
and pressure, the acidified mixture is discharged from the acid
pressure vessel and transferred to a second pressure vessel. At the
second pressure vessel, ammonia is injected to the mixture either
at the second pressure vessel inlet or directly into the second
pressure vessel. The amount and form of ammonia added is determined
by one of ordinary skill in the art from the amount of acidified
mixture or organic materials being treated and the desired result,
which includes but is not limited to one or more of, achieving a
predetermined temperature or pressure or liquefying the mixture.
The addition of ammonia increases the temperature of the mixture
liberating steam which increases the headspace pressure within the
second pressure vessel. Pressures can again be regulated with
pressure relief valves and are preferably maintained between 50
psig and 200 psig, more preferably between 75 and 150 psig, and
more preferably between 100 psig and 130 psig (or any combinations
of these ranges). Preferably the ammonia addition is performed for
a retention period of time that is equivalent to the time required
to inject the ammonia and complete the ammoniation reactions.
Preferred periods of time are between 1 and 30 minutes, more
preferably between 3 and 15 minutes, and more preferably between 5
and 10 minutes (or any combinations of these ranges). Also, time to
inject ammonia and complete the ammoniation reactions may be
dependent on the amount of acidified mixture present and/or the
amount and/or form of ammonia added. The pH at this point is
preferably from about 1.5 to about 7.5, and more preferably from
about 6.0 to about 7.0.
[0067] The processes of the present invention with biosolids and
others forms of organic materials produce a fertilizer that is
preferably safe to handle and work with and preferably meets and/or
exceeds the minimum requirements of a USEPA Class A biosolids.
Fertilizer product is preferably sterilized and biological and
chemical contaminants are at least partially and preferably
completely hydrolyzed and biological agents or organisms are
denatured to the point of inactivation and/or destruction. Typical
biological or chemical contaminants include, but are not limited to
one or more of pharmaceutical compounds, antibiotics, hormones,
hormone-like molecules, biologically active compounds,
macromolecules, carbohydrates, lipids, proteins, nucleic acids, and
combinations thereof.
[0068] The present invention preferably includes a stress
conditioning over a predetermined retention period that creates
stress conditions that meet or exceed those associated with
traditional autoclaving of materials. This autoclave effect
destroys and/or inactivates or simply sterilizes the organic
material. Microorganisms in the organic material, including for
example, bacteria, viruses, fungi, parasites, parasite eggs,
bacterial and fungal spores and combinations thereof, are destroyed
and/or inactivated. In addition, the processes of the invention are
preferably designed to hydrolyze macromolecules such as proteins,
nucleic acids, lipids, fats, carbohydrates and combinations
thereof, and/or other biologically-active substances that may be
present.
[0069] At any time during the steps of the method, one or more
hardening agents can be added to the mixture. Preferred hardening
agents include, but are not limited to ferric oxides, alum
attapulgite clay, industrial molasses, lignin, ligno sulfonate,
urea formaldehyde polymerizer and combinations thereof.
[0070] At the desired time, which may be determined empirically or
experimentally, the liquid is processed into fertilizer. Preferably
processing involves transfer to a granulator for removal of water
and formation of dried fertilizer granules. Preferred is processing
in a granulator which contains 60-88 percent by weight old
granules, and drying the granules preferably with heat to greater
than 90 percent solids, and preferably 98 or 99 percent solids or
greater. Preferably, water extracted from the granules is collected
with a portion recycled in the steps of the process and the
remainder treated for discharge. Granules are typically quite hot
during the drying process and, optionally, may be allowed to cool
by transfer to a cooling room or cooling apparatus. During cooling,
ozone may be injected into the cooler as an odor control measure.
Preferred amounts of ozone to be injected are from 0.01% to 5% of
the weight of the cooling granules, more preferably from 0.1% to 2%
and more preferably from about 0.5% to 1%. Preferably, ozone is
introduced to the cooling apparatus by sparging.
[0071] Once dried and formed and optionally after cooling, the
granules are sized and preferred are granule size of 0.5 mm to 4
mm. More preferred are standard fertilizer granules of about 2.8 mm
and specialty "mini" granules of about 1 mm.
[0072] One or more commercially available hardening agents can be
added to the granulator. Preferred hardening agents include, but
are not limited to ligno-sulfonate, lignin, molasses, or a
combination thereof. Granules of greater than 4 mm and less than
0.5 mm are recycled in the granulator. Granules of the desired size
are further processed by coating with one or more commercially
available dust control agents. Preferably, granules greater than 4
mm are crushed and mixed with the granules of less than 0.5 mm, and
all is recycled in the granulator.
[0073] The invention preferably provides for both dust and odor
control systems to ensure community acceptance of the manufacturing
plant and to facilitate meeting USEPA standards as well as making
the process more efficient through the capture and incorporation of
valuable nitrogen or other potential and/or fugitive plant
nutrients from the processed air of the plant.
[0074] Another embodiment of the invention is the fertilizer
manufactured by the methods of the invention. The physical and
chemical characteristics of organically modified ammonium sulfate
fertilizer of one preferred embodiment of the invention are listed
in FIG. 4. Fertilizer from organic materials such as biosolids may
be powdered or in blocks, or is preferably in the form of granules
that are of a predetermined size and are resistant to crushing
after polishing as compared to unpolished granules. Further,
preferred granules have a smooth exterior with few pits or crevices
and circular or oval in shape. Preferably, the fertilizer contains
no or negligible detectable un-hydrolyzed polymers and preferably
the polymers within the organic mixture have been hydrolyzed
including, but not limited to plastics, pharmaceutical compounds,
antibiotics, hormones, hormone-like molecules, biologically active
compounds, macromolecules, carbohydrates, nucleic acids, fats,
lipids, proteins, and microorganisms. Hydrolyzed polymers form
monomers of the polymer that accumulate in the product and are
preferably amino acids.
[0075] The process of the invention preferably results in the
production of granules or pellets of USEPA Class A fertilizer
product of suitable dryness, hardness, and chemical quality to
produce a valuable, high-nitrogen, controlled release (e.g. slow
release or dual release) commercial fertilizer product that is
capable of competing in the national and international marketplace
against traditional inorganic fertilizers. A commercial,
high-nitrogen fertilizer preferably has greater than 8 percent
nitrogen by dry weight of the finished fertilizer and more
preferably at least 16 percent nitrogen by dry weight of the
finished fertilizer. The Class A characteristic refers to the
microbiological quality of the finished fertilizer product, which
meets the United States Environmental Protection Agency Class A
microbiological standards for a product containing municipal
biosolids as defined in 40 C.F.R. .sctn.503. Also, fertilizer of
the present invention meets or exceeds this standard on the basis
of the stress condition and the retention time utilized thus
ensuring that the associated USEPA Vector Attraction Standards are
met (90 percent solids or greater in the finished product), that
the finished fertilizer granule is optimized for minimal water
content increasing hardness characteristic and eliminating water
with respect to transportation of the finished fertilizer. The
percent solids of the finished product are preferably greater than
92 percent solids, more preferably greater than 97 percent solids,
and more preferably greater than 99 percent solids.
[0076] Biosolids treated according to the processes of the
invention typically contain low levels of metals such as arsenic,
cadmium, copper, lead, mercury, molybdenum, nickel, selenium and/or
zinc. Low levels are levels below what are considered harmful and
less than the Exceptional Quality ("EQ") standard for metals as
published by the USEPA for products containing municipal biosolids.
Thus, by exceeding the USEPA regulation and the hydrolyzing
conditions of the hydrolyzer or pressure vessel for macromolecules
(e.g., personal pharmaceutical products such as antibiotics or
hormones or hormone-like substances), the resulting fertilizer is
safe for use in and around farming, plants, and animals and is
exceptionally safe for handling by workers during processing,
handling, distribution and sales.
[0077] As the fertilizer product produced contains both biosolids
and a high-content of desirable nitrogen, a preferred embodiment
results in a variety of specific nutrient formula fertilizers of
which the following are typical: 16-0.5-0-18-3-15 or
16-0.5-2-17-3-14
(Nitrogen-Phosphorus-Potassium-Sulfur-Iron-Organics) slow release
granular fertilizer that is at least 99 percent dry and exceeds the
United States Environmental Protection Agency (USEPA) Class A
requirements and Exceptional Quality (EQ) Standards. The 16 percent
controlled-release organic nitrogen component helps bind the
nitrogen in the root zone when and where it is needed. For example,
the nitrogen in the ammonium ion, because it is bound to components
of the biosolids, migrates slowly through the root zone and stays
available to the plant rather than being volatized or lost to the
ground water below the root zone. As a result, it may be absorbed
into the plant slowly over time.
[0078] The fertilizer product may be tailored to a desirable
content of elemental components. Preferably the fertilizer has a
nitrogen content of between 6 and 20 percent, more preferably from
8 to 18 percent, a phosphate content of between 0 and 10 percent,
more preferably from none to 5 percent, a potassium content of
between 0 and 5 percent, more preferably from one to four percent,
a sulfur content of between 10 and 30 percent, more preferably from
15 to 20 percent, an iron content of between 0 and 10 percent, more
preferably from one to four percent, and an organic content of
between 5 and 30 percent, more preferably from 10 to 20 percent (or
any combinations of these ranges).
[0079] The fertilizer product contains nitrogen in the form of
ammonium ions non-covalently bound to organic and other chemical
compounds of the fertilizer. Unlike ammonium sulfate fertilizer,
the bound ammonium ions are not all immediately released into the
soil upon application. Instead, there is an immediate release of a
bolus of nitrogen to the soil that represents from about 30-60
percent of the available nitrogen of the fertilizer. This fast
release is typically over a period of one to two weeks, slower than
a conventional ammonium sulfate fertilizer that typically releases
90 percent or more of its available nitrogen to the soil in about 5
to 10 days, but slightly faster than or equal to nitrogen release
of conventional pure biosolids fertilizers. Over the subsequent
days and weeks, the bulk of the remaining nitrogen of the
fertilizers of the invention gradually releases into the soil. Sun,
heat, water and/or microbes in the soil act on the fertilizer and
slowly break down the ionic bonds releasing available nitrogen to
the roots of the plant. Preferably, the nitrogen release is about
from about 1% to 5% per week, and more preferably from about 2% to
4% per week. A small amount of nitrogen may be covalently bound to
compounds of the fertilizer, and thereby remain unavailable to the
plant. Preferably this amount of unavailable nitrogen is 5% or
less, more preferably 2% or less, and more preferably 1% or less of
all nitrogen of the fertilizer product. This dual nitrogen-release
profile is unavailable with conventional fertilizers.
[0080] Dual release fertilizers of the invention allow for a single
application of fertilizer that provides a bolus of nitrogen to
growing or emerging plants such as commercial crops (e.g., fruits,
vegetables, grains, trees), then a continued amount preferably over
an entire or part of a growing season (e.g., see FIG. 7). This
minimizes the number of fertilizer applications needed per crop
which provides substantially savings in application expenses.
[0081] Another embodiment of the invention is directed to a process
for manufacture of a fertilizer with a predetermined content of one
or more of nitrogen, phosphate and/or potassium. Processing of
organic materials proceeds as described herein wherein the acid
selected is of the type and amount desired in the final fertilizer
product. For example, using a set amount of phosphoric acid will
result in a set amount of phosphate in the final fertilizer
product. By using a particular amount of sulfuric acid, a
particular amount of sulfur will be retained in the fertilizer. By
selecting the type and amount of acid, one can pre-select the
content of the fertilizer product produced. Preferably, the
fertilizer is supplemented with one or more plant nutrients added
during one or more steps of the processing. The one or more plant
nutrients include, but are not limited to urea, ammonium nitrate,
ammonium sulfate, monoammonium phosphate, diammonium phosphate,
urea ammonium nitrate, liquid urea, potash, iron oxide, soluble
iron, chelated iron, micronutrients like magnesium, manganese,
copper, zinc, molybdenum or boron, and combinations thereof.
[0082] Another embodiment of the invention is directed to a system
for the manufacture of a fertilizer. The invention comprises a
mixer that blends the organic component containing biosolids,
optionally with an odor control agent. The mixture is then heated
either in this mixer or in a separate heating vessel. Heating the
mixture preferably involves continuous mixing or agitation during
the addition of heat either through indirect heating, e.g., heated
container walls or heated mixers, or direct heating, e.g.,
injection of steam or heated air. The heated mixture is then
transferred to a first pressure vessel. The pressure vessel is
preferably of a construction that allows for a vigorous mixing with
continuous exothermic reaction with the conditioned acidic
biosolids paste. An agitator/mixer is incorporated into the first
pressure vessel. Optional heating elements that may be external to
or internal within the vessel may also be incorporated into the
pressure vessel. Acid may be blended directly with the heated
biosolids in the first pressure vessel or, preferably, the acid and
heated biosolids are combined in a mixing tee and together added to
the pressure vessel. Within the pressure vessel heat and pressure
buildup is continued for a period of time to form a liquid from the
paste-like biosolids mix. The liquid mix may be further treated in
the same pressure vessel, or preferably transferred to a second
pressure vessel through a pipe or conduit. The mix is preferably
transferred in a turbulent flow so as to prevent or minimize the
possibility of biosolid material remaining in the conduit. Also
preferably, the acidified liquid mix is combined in a mixing tee
with the ammonia from an ammonia source, preferably liquid ammonia,
and together forcibly injected to the second pressure vessel.
Preferably the liquid mix is forced through the conduit by
pressurized gas that is added to the system behind the liquid
mixture to ensure that all of the liquid mix has been transferred
to the second vessel. Preferably the gas, which may be air or
another gaseous compound or mixture, is purged by way of a relief
valve in the second vessel. Within the second pressure vessel, the
acidified and nitrogen-fortified liquid mix exothermically heats to
and/or is heated to a second predetermined temperature and
pressurized to a second predetermined pressure for a second period
of time. Preferably the ammonia source is liquefied and/or
vaporized ammonia under pressure. Also preferred, is a system
whereby the first and second pressure vessels each contain an
agitator or other mechanism that continually mixes the mixture.
Alternatively, the first and second pressure vessels may be the
same. Following ammoniation, the mixture is transferred to a
pugmill or granulator wherein the steam and water vapor is released
and the ammoniated liquid is mixed with preformed granules
(commonly referred to as "recycle" to form or shape the new
fertilizer granules. These granules are then heated in a rotary
dryer or fluidized bed dryer to form dried granules of the
fertilizer. In a preferred embodiment, the entire reaction process
is controlled by a closed loop computer control that continuously
monitors and adjusts the exothermic reaction through addition of
sulfuric acid, ammonia, plant nutrients, pH adjusters and pressure
control. The preferred control mechanism is through adjustment of
the head space pressure above the biosolids in this pressure
vessel. The system also preferably contains a conveyer (e.g. pump
or screw conveyer, conveyer belt) for transporting biosolids to the
mixer and another pump for transporting the blended biosolids to
the first pressure vessel; a pressurized piping system that
transports acidified biosolids from the first pressure vessel to
the second pressure vessel, ammonia into the second pressure
vessel; and disperses the ammoniated liquid to the granulator.
Thus, the entire process is carried out without the need for
stopping the continuous flow of biosolids into and out of the
pressure vessels.
[0083] From the granulator, or incorporated with it, is preferably
a rotary dryer or alternatively a fluidized bed dryer that further
dries the biosolids fertilizer to less than 1 percent water
content. Upon exiting the dryer, the biosolids fertilizer is
further screened for size and separated into product, undersize and
oversize granule groups. The undersized particles are recycled back
into the entrance of the second pug-mill. The oversized particles
are sent to a hammer mill where they are crushed and then recycled.
After leaving the screening process the biosolids fertilizer
granules are processed through the rotary cooler where the
biosolids fertilizer is cooled. Optionally, the cooler may include
an ozone generator that provides ozone to the cooling fertilizer.
In the presence of ozone, odor-causing material complexes with
oxygen and possible other molecules present in the biosolids and
substantially reduces or eliminates disagreeable odors. The
fertilizer granules empty into the final polishing screens to
remove undersize granules or dust created in the cooling process.
After processing through the polishing screens, the product passes
through a coating drum where a coating agent that inhibits dusting
is added. The biosolids fertilizer is then warehoused ready for
bulk shipping or subsequent packaging. Alternatively, granules may
be subject to an air polishing system that continuously recycles
the hot air generated in the cooling process to the drying stage
resulting in a reduction in fuel usage and waste air for
processing. The air drawn from the screens and equipment is cleaned
in a dust collector, cooled through a heat exchanger and reused as
inlet air to the cooler. The heated air discharging from the cooler
is again cleaned in a dust collector. The cleaned, heated air is
used as inlet air for the rotary dryer. The system also preferably
contains one or more screens for selecting granules of a
predetermined size and a rotary cooler for cooling and polishing
the sized granules. The system of the invention preferably
comprising a dust control apparatus such as, for example, vacuums
and baghouses that collect dust from the granulator and also a
water recovery system whereby water extracted from biosolids during
processing is recovered and recycled rendering the system very
efficient.
[0084] In a preferred embodiment, process air is acid scrubbed to
remove any fugitive odorants and especially vaporized or gaseous
ammonia. The captured ammonia, as an ammonium salt is mixed back
into the biosolids mix prior to its entering the reaction vessel or
mixer thereby increasing the efficiency of the entire system and
maximizing the final nitrogen concentration in the finished
fertilizer. Miscellaneous residuals including dust,
non-specification or reclaimed product and dried fertilizer that is
too small or undersized or oversize material that is crushed in a
crushing or mill apparatus or may include other additives, e.g.,
iron that a customer would prefer can be added to the composition
of the finished fertilizer are added to an optional pug-mill or
mixer positioned downstream from the pressure vessel or directly
into the granulator. During the granulation process, a hardener or
hardeners which help to agglomerate the mix and contribute to the
hardness of the dried pellet or granule are added at the second
pug-mill or granulator. The hardener or hardeners are selected from
the group comprised of attapulgite clay, lignin, industrial
molasses, and alum among others or mixtures of these hardeners as
known by one skilled in the art.
[0085] Optionally, dependent upon the requirements of the customer,
additional plant nutrients, for example, potash or other forms of
potassium, e.g., potassium hydroxide, are preferably added at the
pug mill or granulator. The solid nutrients that may be added also
comprise urea, ammonium nitrate, mono-ammonium phosphate,
diammonium phosphate, zinc chloride, and/or potash. Also added in
this second pug-mill is any additional iron required. The iron
contributes an important and valuable plant nutrient to the
fertilizer mix.
[0086] Also, additional ammonia may be sparged into the pug-mill
and into the granulator directly to complete the formation of the
ammonium salt and to control the pH of the mix and to facilitate
the formation of the finished granule. The solids used to adjust
the pH may also be principally alkaline agents selected from the
group comprised of calcium carbonate, sodium hydroxide, calcium
oxide, cement kiln dust, lime kiln dust, Class C fly ash, Class F
fly ash, multistage burner ash, alum, alum biosolids from water
treatment and wood ash. These are added via screw conveyors at
specific rates for each compound. The liquid additions also include
pH adjustment materials such as acids, e.g., phosphoric acid or
sulfuric acid, or caustic solutions, e.g., sodium hydroxide. These
are pumped at respective rates to the injection ring to enter the
pug-mill.
[0087] The fertilizer product of the present invention preferably
has a pH of between 5.0 and 7.0, more preferably between pH 5.8 and
pH 7.0, and more preferably between pH 6.2 and pH 6.9. The
remainder of the processing for shaping as in pellet or granule
production includes standard fertilizer granulation technology
especially for high volume throughput plants. The pellet or granule
product, especially in smaller throughput plants considered to be
those of less than 25 tons of product production per day, may
involve more innovative technologies such as injection or extrusion
followed by milling or spherulizing the pellet or granule or
involves simple discharge from a granulator or granulating
pug-mill. When a granulator or granulating pug-mill is used, it is
preferable to feed some recycle, as in dry seed material, i.e., dry
fines and fines produced by the crusher or mill or
sub-specification or reclaim material of the fertilizer product,
into the pug-mill and the granulator to adjust the percent moisture
present in the mix so that agglomeration or nucleation can occur
resulting in granule formation.
[0088] Other preferred embodiments comprise adjustments to the
processes disclosed herein. Embodiments incorporate a pelletizer in
place of the granulator in the process train. The pelletizer may
include the drying step to the preferred dryness or the formed
pellets may then be transferred to a dryer, preferably a fluidized
bed dryer to reach the preferred dryness. These other embodiments
may also incorporate adjustments to control pH, dryness, nutrients
in the product, shape, concentrations etc. to produce a plethora of
fertilizers specific for different plants such as roses,
rhododendrons, and any other flowers, vegetables, herbs, as well as
products such as cat litters. Adjustments can also be made
according to the geographic area in which the product is to be
applied, to vary, for example, nutrients that may be inherently or
otherwise missing in the location. Examples of such variations
include the addition of calcium, potassium or phosphorus in
different amounts.
[0089] Normal drying for final drying is conducted using a
horizontal fluidized bed dryer, or a rotary drum dryer. The dried
pellets or granules which are greater than 92 percent solids and
preferably are greater than 95 percent solids and more preferably
are greater than 98 percent and even more preferably are greater
than 99 percent solids are then sized through one or more screens.
The specification size may be varied dependent upon customer
requirements, however, the range of suitable product for sale is
between 0.5 mm and 4 mm with the commercial range for normal sized
fertilizer is between 2 mm and 3 mm. The present invention also can
manufacture a minimal sized product suitable for use in golf course
applications which ranges from 0.5 mm to 1.3 mm. The proper sized
material is separated and then cooled and then coated and then
cooled in an apparatus, preferably a rotary drum, to less than
60.degree. C. (140.degree. F.), preferably to less than 49.degree.
C. (120.degree. F.) and more preferably to less than 43.degree. C.
(110.degree. F.). Cooling the granule or pellet optimally occurs in
a rotary drum apparatus using ambient air or cooled air as from an
ammonia evaporation cooler. Coating may occur in a coating vessel
specifically for that purpose typically a rotary drum or a mixer.
Alternatively, cooling and coating may be accomplished in a single
vessel which cools the material and mixes the coating agent with
the granules. Coating is with a de-duster or glazing material which
minimizes dust generation during transport, storage and
application. The finished coated granule or pellet is then conveyed
to storage as finished high nitrogen containing bioorganic-enhanced
inorganic ammonium fertilizer until shipment from the manufacturing
site. Properly coated and dried pellets or granules have a hardness
of greater than 5 pounds crush resistance in order to resist
dusting and handing during transport, shipment and application. The
de-duster coating or glazing material often requires a higher
temperature, often 71-105.degree. C. (160 to 220.degree. F.), to
maintain a molten condition for application in the coating
apparatus.
[0090] The granule storage facility or warehouse, usually
incorporating bins or silos to contain the granules, must be dry to
prevent agglomeration of the granules leading to degradation and
destruction. The finished product is upon manufacture a sterile
fertilizer having substantially no detectable amount of viable
microorganisms, such as E. coli or streptococci, harmful to animals
or humans. Substantially no viable microorganisms means that the
fertilizer is microbially-safe and has no detectable amount or a
detectable amount well below a threshold for safe handling and use
of microorganisms originating from the biosolids. Although the
fertilizer is rendered sterile during manufacturing, contamination
can be expected from air-borne microorganisms or by microorganisms
deposited by animal or other contamination during storage or use.
In any case, because the fertilizer product is dry and
predominantly inorganic ammonium salts will not support
microorganism multiplication at a rate which would lead to a public
health problem.
[0091] During normal operations periodic shutdown plant equipment
will be necessary for inspection, repair, or replacement. This is
done to different degrees depending on specific situations. In one
embodiment, shutdowns are automatic as in an automated command
sequence provided by the plant control processor; in another
embodiment, the shutdowns are carried out manually.
[0092] If a limited shutdown of the process is necessary to a
single piece of equipment the flow of biosolids into the reactor
vessel would stop Material in the lines prior to the first pressure
vessel are evacuated into the organic mixture mixer(s). Material in
the pressure vessels and associated piping are evacuated using
alternate valve and piping systems and air pressure to the
`recycle` bed of granules in the granulator or if not available to
an emergency storage tank system provided for such events. In the
pressure vessel, after the fertilizer mix drops to below the normal
discharge point, a diverter valve on the discharge closes sealing
off the pressure vessel normal discharge. The diverter valve at the
bottom of the pressure vessel then shifts, allowing the compressed
air entering the head space of the pressure vessel to force
remaining material into the return fertilizer mix line. If further
cleaning is needed, process water is then injected into the
pressure vessel followed by compressed air to purge the water.
Cleanout of the granulator, the dryer and all subsequent equipment
is performed by running them until the vessels are empty.
[0093] The fertilizer of the present invention is preferably
chemically adjusted to fit the needs of high nitrogen fertilizer
requirements containing significant amounts of phosphate, sulfur
and iron to enhance the targeted nitrogen (N) content of between 8
and 18 percent by weight, and preferably 16 weight-percent
permitting significant commercial valuation.
[0094] FIGS. 1A, 1B and 1C, and FIGS. 2A, 2B, and 2C provide
schematic diagrams of embodiments of the present invention, wherein
the process of these embodiments utilizes dewatered municipal
biosolids combined with additional plant nutrients, ammonium salt
fertilizers, and binding agents. In this example, the biosolids to
be treated is a dewatered biosolids, often referred to as a
"biosolids cake." This biosolids are delivered to the manufacturing
facility where they are stored in a storage bin until the biosolids
are ready to be conditioned. The conditioning initially takes place
in a first pugmill by a vigorous mixing or blending with iron or
other agent for odor control, along with optional oxidizing agents,
which converts the thixotropic biosolids into a pumpable mix,
paste, or paste-like mix. The iron and/or oxidizing agent reacts
with reduced sulfur compounds and other odorants present in the
biosolids. If phosphoric acid is added to this first pugmill it
assists in modifying odorants present in the biosolids and
contributes the majority of the phosphorus nutrient found in the
final product. As the biosolids proceed through the equipment train
additional plant nutrients can be infused into the mix. In this
embodiment biosolids are heated during their passage through the
pugmill prior to being pumped to the first reaction vessel. In the
preferred embodiment shown here two sulfuric acid streams (in a
concentration range of 68 percent up to 105 percent sulfuric) are
injected into the vessel where in the mix is acidified and
liquefaction commences. Once the mix exits the first pressure
vessel it is transferred under pressure into a second pressure
vessel where the primary nitrogen infusion reaction occurs. In this
figure, a sparger injects ammonia (or other nitrogen source) as a
gas or liquid. This reaction in both vessels is carefully
controlled to optimize temperature, pressure, retention time, pH,
and nitrogen, all of which can be empirically determined based on
the input biosolid materials and the desired output content of
treated and dried biosolids. The pressure vessels include a
plurality of valves and controls that serve to automate the system.
Additives can be used to control the temperature, pressure, and pH
and nutrient levels. The nitrogen source that is pumped into the
pressure vessel comprises a base, such as anhydrous or aqueous
ammonia. A mix of biosolids and ammonium sulfate and ammonium
phosphate is formed that becomes molecularly integrated in that the
ammonium ions become electrically bound to the amphoteric organic
molecules from the bio solids thereby creating a slow-release or
controlled-release nitrogen in the final fertilizer granule.
Similarly, this electric bonding can occur between the sulfate and
phosphate and iron molecules present in the mix thereby rendering
these nutrient molecules similarly to a slow-release or controlled
release state. This mix is maintained in a stress condition for a
retention period as determined by its retention time (which in turn
is based on the head pressure and volume as described herein) as
the mix moves through the pressure vessel. The stress condition
preferably includes elevated temperature, and/or elevated pressure.
The elevated temperature is produced partly or entirely by the
exothermic reaction of the components, which can increase the
temperature of the mix. At these temperatures steam is generated
from the mix. This steam is allowed to exit the pressure vessel
under valve-controlled release, accomplishing a partial drying of
the mix. The stress condition the biosolids undergo in the pressure
vessel and the retention period are controlled so as to result in
the production of a mix that is sterile and that contains
hydrolyzed macromolecules from the biosolids. Control of the stress
condition and the retention period also results in the fusion of
the ammonium ions formed with the organic molecules present
creating a natural slow-release property for the nitrogen present,
and the denaturization and or hydrolysis of many macromolecules
present in the biosolids, such as proteins, plastics and other
polymers. When such molecules are biologically active, this
denaturization and/or hydrolysis renders them less active or
inactive thereby creating a safer mix for public usage or exposure.
The retention time to induce the necessary fertilizer properties
and biological inactivation are controlled by the continuous
pumping and flow of the biosolids into the pressure vessel. This
continuous flow processing of the invention versus the traditional
batch processing of older plants aids the high throughput of this
invention. The continuous flow also minimizes the problems
associated with clogging of the process necessitating down time to
clear the clog.
[0095] The new liquid biosolids mixture flows from the pressure
vessel and, optionally, is mixed with a hardening agent or agents
and possibly additional nutrients to fine tune the fertilizer as
desired. That mix is further treated by granulation or extrusion
into granules such as pellets or other, smaller structures. The
granules are dried in rotary dryer and passed through one or more
screens to separate oversized materials and undersized materials
from proper-sized materials. The oversized materials can be crushed
in a crusher or mill. Subsequently, the undersized materials and
the crushed oversized materials can be recycled to facilitate the
granulation of the fertilizer mix. The resulting proper-sized
granules are then dried in rotary cooler, sized, coated, cooled and
stored. When a traditional granulator is used in the shaping
process, ammoniation by vaporized ammonia and recycle addition may
occur. Water removed from the mix as steam from the pressure vessel
and from subsequent vessels as steam and/or water vapor may be
condensed and preferably returned to the wastewater treatment plant
(WWTP), or may be treated and discharged into adjacent water
resources, or into the atmosphere. Water that is retained from the
capture of ammonia in the process emission air is returned to a
process water containment vessel. For optimal odor control of the
process and optimization of the odor of the resultant fertilizer
from the present invention this process water may be treated with
25 percent to 50 percent liquid hydrogen peroxide to eliminate most
of the chemical odorants associated with this process water before
it is subsequently added to the biosolids mix immediately prior or
in the first pugmill. Alternatively, the odorous process water can
be treated with gaseous ozone which is bubbled by diffuser through
the process water thereby also eliminating the majority of odorant
associated with this water.
[0096] In another embodiment a series of reaction vessels may be
used to accomplish the acid/base reactions described herein. In a
preferred embodiment of the present invention the sequence of two
reactor vessels can be utilized. In one optional embodiment a
combination of one reactor vessel for acid reaction can be followed
by an ammoniation conducted in a pipe-cross reactor. Alternatively,
in another embodiment the reactions could be carried out in the
sequence of a first pipe-cross reactor for acidification of the
biosolids mix followed by the ammoniation conducted in a pressure
vessel. Also described is an embodiment whereby the acidification
reaction is conducted in a first pipe-cross reactor followed by the
ammoniation reaction in a second pipe-cross reactor.
[0097] Another embodiment of the present invention can have the
acidification of the biosolids mix to partly or fully occur in the
first pugmill. The partly or fully acidified biosolids mix could
then be treated by ammoniation in a first reaction vessel. If the
mix were partially acidified the acid/base reaction could then be
completed in this first vessel or the incomplete mix transferred to
a second reactor vessel (or pipe-cross reactor) for completion.
[0098] Another embodiment of the invention is directed to a system
for the manufacture of a product from organic materials treated in
accordance with the method of the invention as described herein.
The combination of pressure, heat and ammonia treatment destroys or
otherwise inactivates toxins and other hazardous compounds that are
present in an otherwise contaminated organic material. The
resulting product may be used as a fertilizer or other nutrient or
support for plants and/or animals, or in another industry such as,
for example, construction or habitat creation.
[0099] The following examples illustrate embodiments of the
invention, but should not be viewed as limiting the scope of the
invention.
EXAMPLES
Example 1
[0100] To 900 grams of raw bio solids with a solids content of 16
percent were added 15 grams of process water, 38.6 grams of iron
sulfate, and 21.8 grams phosphoric acid. The mixture was thoroughly
mixed (10 rpm) to a viscosity of about 1,250 cP, and then heated in
an agitated pressure vessel to about 54.degree. C. (130.degree. F.)
and vented to maintain atmospheric pressure of 0 psig (ambient).
411.4 grams of 93 percent sulfuric acid were added to the heated
mixture and allowed to attain maximum temperature for 5 minutes.
The temperature of the mixture rose to about 104.degree. C.
(220.degree. F.) and the vessel was vented to maintain atmospheric
pressure at 0 psig. The viscosity ranged from 760 cP to 3630 cP
dependent on induced shear rates.
Example 2
[0101] To 730 grams of raw biosolids with a solids content of 23.5
percent were added 56 grams of process water, 45.9 grams of iron
sulfate, and 25.9 grams phosphoric acid. The mixture was heated in
an agitated pressure vessel to 54 C (130 F) and vented to maintain
atmospheric pressure of 0 psig. 490.1 grams of 93 percent sulfuric
acid were added to the heated mixture and allowed to attain
temperature and maximum pressure for 5 minutes. The temperature of
the mixture rose to about 116.degree. C. (241.degree. F.) and the
pressure to a maximum of 40 psig. At the maximum pressure, 165
grams of ammonia were added and the ammoniated mixture allowed to
attain temperature and maximum pressure for 5 minutes after which
the temperature rose to 183.degree. C. (362.degree. F.) and the
pressure rose to 111 psig. The viscosity was about 518 to 968 cP
dependent on induced shear rates.
Example 3
[0102] To 720 grams of biosolids with a pH of 6.7 and a solids
content of 24.5 percent were added 50 grams of process water, and
47.2 grams of iron sulfate. The mixture was thoroughly mixed and
then heated in an agitated pressure vessel until reaching about
54.degree. C. (130.degree. F.), and a maximum pressure of 26 psig.
503.9 grams of 93 percent sulfuric acid were added to the heated
and pressurized mixture. The temperature of the mixture rose to
114.degree. C. (238.degree. F.) and the pressure to a maximum of 58
psig. After 5 minutes and at the maximum pressure, 170 grams of
ammonia were added and the ammoniated mixture was allowed to attain
temperature and maximum pressure for 5 minutes after which time the
temperature of the mixture rose to 182.degree. C. (360.degree. F.)
and the pressure to 109 psig. The liquefied mixture was then
sprayed into a granulator and the entire mixture was dried. The
resulting mixture in the granulator contained about 80 percent by
weight of recycled fertilizer granules. Granules were sized to
about 2 to 4 mm in size and tested for content. Granules were found
to contain 16(N)-2(P)-0(K)-175(S)-1(Fe)-15(Org).
Example 4
[0103] To 720 grams of biosolids with a pH of 6.45 and a solids
content of 23 percent were added 100 grams of process water, and
146 grams of iron sulfate. The mixture was thoroughly mixed and
then heated in an agitated pressure vessel until reaching about
54.degree. C. (130.degree. F.), and a maximum pressure of 23 psig.
406 grams of 93 percent sulfuric acid were added to the heated and
pressurized the mixture. The temperature of the mixture rose to
111.degree. C. (232.degree. F.) and the pressure to a maximum of 34
psig. After 5 minutes at the maximum pressure, 166 grams of ammonia
were added and the ammoniated mixture was allowed to attain
temperature and maximum pressure for 5 minutes after which time the
temperature of the mixture rose to 176.degree. C. (348.degree. F.)
and the pressure to 106 psig. The liquefied mixture was then
sprayed into a granulator and the entire mixture was dried. The
resulting mixture in the granulator contained about 80 percent by
weight of recycled fertilizer granules. Granules were sized to
about 2 to 4 mm in size and tested for content. Granules were found
to contain 16(N)-0(P)-0(K)-175(S)-3(Fe)-15(Org).
Example 5
[0104] To 600 grams of biosolids with a pH of 6.54 and a solids
content of 23 percent were added 130 grams of process water, and
158.9 grams of iron sulfate. The mixture was thoroughly mixed and
then heated in an agitated pressure vessel until reaching about
54.degree. C. (130.degree. F.), and a maximum pressure of 21 psig.
511.7 grams of 93 percent sulfuric acid were added to the heated
and pressurized mixture. The temperature of the mixture rose to
118.degree. C. (244.degree. F.) and the pressure to a maximum of 46
psig. After 5 minutes and at the maximum pressure, 183 grams of
ammonia were added and the ammoniated mixture was allowed to attain
temperature and maximum pressure for 5 minutes after which time the
temperature of the mixture rose to 175.degree. C. (347.degree. F.)
and the pressure to 107 psig. The liquefied mixture was sprayed
into a granulator and the entire mixture was dried. The resulting
mixture in the granulator contained about 80 percent by weight of
recycled fertilizer granules. Granules were sized to about 2 to 4
mm in size and tested for content. Granules were analyzed found to
contain 16(N)-0(P)-2(K)-185(S)-3(Fe)-13(Org).
Example 6
[0105] Nitrogen release profiles of the organically modified
ammonium sulfate of the invention are determined in comparison to
traditional, pure ammonium sulfate fertilizer and pure biosolids as
controls. First, ammonium sulfate is applied over sterilized sand
in a laboratory environment (ambient temperatures with no sun,
water or soil organisms) and allowed to permeate the sand over a
period of time. As can be seen in FIG. 5, about 90 percent of the
nitrogen of the pure ammonium sulfate fertilizer travels through
the sand within less than one week. Next, nitrogen penetration is
compared between pure ammonium sulfate (AS), pure biosolids
(MILORGANITE), and organically modified ammonium sulfate of the
invention (VITAG). As can be seen in FIG. 6, about 90% of the
nitrogen of AS is released through the sand within about one week
of application. In comparison, about 35 percent of the nitrogen of
traditional biosolids is released which increased to about 70
percent over two weeks where it remained. Organically augmented
ammonium sulfate of the invention released about 60 percent of its
nitrogen within the first week which increased to about 70 percent
over two weeks.
[0106] Also, a theoretical nitrogen release profile is determined
for these same three fertilizer materials in normal soil. Soil is
presumed to contain microorganisms that break down
nitrogen-containing molecules thereby releasing additional nitrogen
into the soil. As can be seen in FIG. 7, ammonium sulfate again
releases its nitrogen content within the first week. Pure biosolids
release only about 30% of its nitrogen in the first two weeks,
which gradually increases to about 90% over a period of 26 weeks.
However, organically modified ammonium sulfate prepared according
to the processes of the invention releases just under 60 percent of
its nitrogen over two weeks which gradually increased to about 90
percent over the next 26 weeks. Thus, organically modified ammonium
sulfate fertilizer prepared according to the processes of the
invention initially releases just over half of its nitrogen and
slowly releases the remaining half over a period of weeks to
months. This two-stage nitrogen release profile (e.g.,
dual-release, two-step release, combined fast/slow release) is
characteristic of the fertilizers of the invention.
[0107] Other embodiments and uses of the invention will be apparent
to those skilled in the art from consideration of the specification
and practice of the invention disclosed herein. All references
cited herein, including all publications, U.S. and foreign patents
and patent applications, are specifically and entirely incorporated
by reference. The term comprising, where ever used, is intended to
include the terms consisting and consisting essentially of. It is
intended that the specification and examples be considered
exemplary only with the true scope and spirit of the invention
indicated by the following claims.
* * * * *