# Patent

## Title
Apparatus for removal and destruction of ammonia from an aqueous medium

## Abstract

Methods and apparatuses are provided for the removal and destruction of ammonia from an aqueous medium. The methods and apparatuses include the removal of ammonia from an aqueous medium by contact with either natural or synthetic zeolite. The spent zeolite is re-generated for continuous use, while the ammonia is concentrated as ammonium sulfate, and ultimately destroyed via combustion. A system for monitoring and maintaining an ammonia removal system by an off-site provider is also disclosed.

## Background
CROSS REFERENCE TO RELATED APPLICATIONS
The present non-provisional patent application claims priority to U.S. Provisional Application Ser. No. 60/325,141, filed on Sep. 26, 2001, entitled METHODS AND APPARATUS FOR REMOVAL AND DESTRUCTION OF AMMONIA FROM AN AQUEOUS MEDIUM USING ZEOLITES, which is herein incorporated by reference.


FIELD OF THE INVENTION
The invention generally relates to the removal and destruction of ammonia from aqueous media. More specifically, the invention provides systems, methods and apparatuses for the effective removal of ammonia from water as it is treated in a water treatment facility, and in particular, to systems, methods and apparatuses for the removal and destruction of ammonia from drinking water by contacting the water with zeolite materials.
BACKGROUND OF THE INVENTION
Cities and towns throughout the world depend on having clean potable water supplies. The dependence on clean water has increased as the population of the world has increased, especially as industrial use of rivers and lakes have become commonplace.
The explosion of world population, and corresponding increase in fresh water use, has resulted in a need to maximize water usage. However, the ability to maximize fresh water use has been limited by, (1) increased pollution of the fresh water supplies due to higher industrial output throughout the world (a direct result of the increased population); and (2) increased knowledge and standards for what constitutes clean water, acceptable for use in farming, industry, and consumption. As a result, there is a current need to increase the efficiency in the use of water, i.e., conserve existing clean water supplies, increase the current capabilities used to remove pollutants from water supplies, and increase the effectiveness of existing technologies and develop new technologies to effectively treat and reach new standards in water quality.
In this light, ammonia contamination of water resources has proven to be extremely problematic. High levels of ammonia commonly occur in wastewater, and occasionally drinking water, as a result of well contamination by industrial and agricultural processes. Presently, there is a trend to lower the ammonia discharge limits for facilities toward a range of 2 to 4 parts per million (ppm) from a previous ranges of 10 to 15 ppm.
Conventional ammonia removal technology has focused on additional aeration at wastewater treatment plant lagoons. In general, this remedy has proven ineffective. In contrast, a number of new technologies, focused on other wastewater related problems, have had the side-effect of lowering ammonia discharges. For example, activated sludge wastewater plants are being constructed to eliminate a full range of biological contaminants and have the added benefit of decreased ammonia discharges to 2 ppm or less. These plants however are expensive and not required in areas where the only problem is high ammonia levels. Further, technologies such as Sequence Batch Reactors (SBR's), Rotating Biological Filters (RBF's), and Trickle Filters are also used to solve non-ammonia related wastewater cleanup problems, but ammonia reduction seems to be an added benefit. However, these newer technological options require entirely new facilities or expensive rebuilds at existing facilities. This is an appropriate response where a wastewater problem is significant and requires a fairly drastic improvement. However, facilities with efficiently operating wastewater plants need options that are relatively inexpensive, compared to rebuilding the entire facility, and focused on lowering the ammonia discharge levels, not on other, typically more expensive, cleanup problems. Against this backdrop the present invention has been developed.
BRIEF SUMMARY OF THE INVENTION
The present invention provides systems, methods and apparatuses for the removal and destruction of ammonia from an aqueous medium using zeolite materials. The zeolite materials of the present invention absorb ammonia at levels sufficient to comply with discharge limits set by the EPA. Spent zeolite is re-freshed and re-used, where the ammonia on the zeolite is stripped and concentrated as an ammonium salt. Stored ammonium salts are used in the manufacture of fertilizers, or simply converted to a form for combustion, and release as nitrogen into the atmosphere.
The present invention also provides methods and apparatus for operating an ammonia removal and destruction facility, in accordance with the present invention, from an off-site location. The system includes providing a pre-determined amount of zeolite for removal of ammonia from the target water source, providing and maintaining the required chemical compounds for the storage or destruction of the ammonia, and operation and maintenance of a combustion unit for conversion of the ammonium to a nitrogen containing gas for release into the atmosphere.
These and various other features as well as advantages which characterize the invention will be apparent from a reading of the following detailed description and a review of the appended claims.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a schematic for the removal and destruction of ammonia in accordance with an embodiment of the present invention.
FIG. 2 illustrates a schematic for the ammonia absorption process in accordance with an embodiment of the present invention.
FIG. 3 illustrates a schematic for the combustion of ammonia in accordance with an embodiment of the present invention.
FIG. 4 illustrates a schematic of the overall removal and destruction of ammonia in accordance with an embodiment of the present invention.
FIGS. 5A, A2, B, B2, C1 and C2 provide a theoretical mass balance calculation for the schematic shown in FIG. 4.
FIG. 6 is graphical representation of bed volume against concentration for the data illustrated in Tables 6 and 7.
FIGS. 7A–H illustrate tabular and graphical data involved in a five column run in accordance with an embodiment of the present invention.
FIGS. 8A–F illustrate tabular and graphical data involved in another five column run in accordance with an embodiment of the present invention.
FIGS. 9A–F illustrate tabular and graphical data involved in another five column run in accordance with an embodiment of the present invention.
FIGS. 10A–F illustrate tabular and graphical data involved in another five column run in accordance with an embodiment of the present invention.
FIG. 11 provides data from a pilot study performed at Colorado City, Colo., showing the feed and discharge levels of ammonia for a 1000 gallon treatment in accordance with embodiments of the present invention.
FIG. 12 is a schematic of the air stripping process in accordance with an embodiment of the present invention.



DETAILED DESCRIPTION OF THE INVENTION
Definitions:
The following definitions are provided to facilitate understanding of certain terms used frequently herein and are not meant to limit the scope of the present disclosure.
“Aqueous medium” refers to water or any liquid made from, with, or by water.
“Feed” refers to an aqueous medium before treatment with the systems and methods of the present invention, for example, a flowing water source before it enters a wastewater treatment facility.
“Zeolite” refers to a natural and/or synthetic zeolite. Natural zeolites are hydrated silicates of aluminum and either sodium or calcium or both, for example clinoptilolite and chabazite. Synthetic zeolites are made by a number of well known processes, for example gel or clay processes, which form a matrix to which the zeolite is added. Example synthetic zeolites include Linde® AW-30 and Zeolon® 900.
“bed volume” for a particular housing member refers to the volume of zeolite in the housing member. The term bed volume, for purposes of the present invention, also refers to the retention volume and/or specific retention volume. Note that bed volume has units of liters, cubic meters, or cubic feet.
“Remove” refers to the detectable decrease of a target material, for example ammonia, from a source, for example ground water. Typically removal of arsenic from an aqueous source is at least 50%, preferably at least 75% and most preferably at least 90%, from the original levels in the zeolite treated source.
“Absorb” and “adsorb” refer to the same basic principle of one substance being retained by another substance. The processes can include attraction of one substance to the surface of another substance or the penetration of one substance into the inner structure of another substance. The present invention contemplates that zeolite can either absorb and/or adsorb ammonia from an aqueous medium and that for purposes of the present invention, that the two principles be interchangeable. Other terms used to describe this interaction include binding or trapping, each of which contemplates absorption and/or adsorption. As used in the present invention, the term absorb refers to any or all of adsorb, trap, bind, and the like.
Zeolite:
Zeolites, in accordance with the present invention, effectively absorb, adsorb, bind and/or trap ammonia in an aqueous media, and thereby remove it from the aqueous media. Compositionally, zeolites are similar to clay minerals, where zeolites are natural hydrated silicates of aluminum and either sodium or calcium or both. Unlike clays, which have a layered crystalline structure (similar to a deck of cards that is subject to shrinking and swelling as water is absorbed), zeolites have a rigid three-dimensional crystalline structure. Zeolites' rigid honeycomb-like crystalline structure consists of a network of interconnected tunnels and cages, thereby forming a series of substantially uniformly sized pores. Aqueous media moves freely in and out of the pores formed by the crystalline structure, making zeolite an excellent sieving or filtration type material, as well as providing a large surface area for binding ammonia within the target aqueous medium. Zeolite is host to water molecules and ions or potassium, sodium, and calcium, as well as a variety of other positively charged ions, but only those of appropriate molecular size fit into the pores, creating the “sieving” property.
There are approximately fifty different types of natural zeolites, including clinoptilolite, chabazite, phillipsite, mordenite, analcite, heulandite, stilbite, thomosonite, brewsterite, wellsite, harmotome, leonhardite, eschellite, erionite, epidesmine, and the like. Differences between the different zeolites include particle density, cation selectivity, molecular pore size, and cation affinity. For example, clinoptilolite, the most common natural zeolite, has 16% more void volume and pores as much as 0.2 nm larger than analcime, another common zeolite.
Preferable natural zeolites for use in the present invention include any zeolite having an exchange capacity with sufficient capacity to lower the ammonia concentration in an aqueous medium from a first level to a second level. Preferable zeolites for use in the present invention have a capacity for ammonia of at least 1 meq/gram, although other lower capacity zeolites are envisioned to be within the scope of the present invention. In addition, zeolites having particle sizes from 10×60 mesh and preferably 20×40 mesh are useful in the present invention. Zeolite fines are typically removed before use in the present invention to prevent plugging in the tanks of the present invention (see below). Preferable natural zeolites for use in the present invention include clinoptilolite.
Table 1 provides a list of companies that presently produce zeolite minerals in either the United States or Canada. Table 1 provides a chemical analysis of the zeolite materials sold by a number of companies, and provides the physical properties of the corresponding zeolite materials. This Table is provided as illustrative of the type of zeolite material that can be purchased for large scale use.







TABLE 1







Chemical Analysis (Expressed in Weight %)
















Company
Location
Na2O
K2O
CaO
MgO
SiO2
Al2O3
TiO2
Fe2O3





Addwest Minerals
WY
4.7
1.9
1.6
0.65
74.0
14.0
0.1
2.1


American Research
NV/CA
3.5
3.8
0.7
0.4
69.1
11.9
—
0.74


Am. Absorbents
OR
0.8
3.8
0.7
0.4
69.1
11.9
0.2
0.7


Stellhead Res.
CA/NM/OR
0.8
3.8
0.7
0.4
69.1
11.9
0.2
0.4


Teague Minerals
OR
0.9
4.7
1.4
0.3
64.1
11.8
0.3
2.58


Zeotech
TX
0.6
1.7
2.4
0.7
68.4
12.1
NK
NK


St. Cloud Mining
NM
0.9
3.3
3.3
1.0
64.7
12.6
0.2
1.8


W-Way Zeolites
Canada
2.5
2.7
3.4
1.3
65.8
14.3
0.3
2.6


Highwood Res
Canada
2.78
2.79
3.78
0.95
64.5
13.7
0.27
2.19


C2C Mining
Canada
1.35
1.57
2.51
1.55
66.8
11.2
0.6
5.2










Physical Properties
















Ionic Exch
H2O %
Free Silica


pH
Pore



Company
Cap (meq/g)
Adsorption
(%)
SG
Color
(nat.)
Diam. (Å)
Hard.





Addwest Minerals
2.00
14.0
2.00
1.5
pale blue

4.4
3.7


American Research
1.85
12.3
NK
NK


4.0
5.1


Am. Absorbents
1.4

1.50
2.3
white
8.0
4.0
3.8


Stellhead Res.
1.30

0.09
1.6
white
8.0
4.0
5.1


Teague Minerals
1.77

low
2.2
off white

not
not









provided
provided


Zeotech


St. Cloud Mining
1.60

  0.01<
2.3
white
8.0
4.0
3.8


W-Way Zeolies
1.00
25.0
NK
2.4
off white/
8.1
6.5
NK







pale green


Highwood Res
1.00

10.0 
2.0

7.0


C2C Mining
NK
NK
5.00
2.3
brown
5.0
NK
NK









It is also envisioned that synthetic zeolites can be used in accordance with the present invention. Synthetic zeolites are made by well known processes, such as a gel process (sodium silicate and alumina) or clay process (kaolin), which form a matrix to which the zeolite is added. Preferable synthetic zeolites include Linde®AW-30, Linde®AW-500, Linde®4-A and Zeolon®900.
It is envisioned that the systems and methods of the present invention can utilize either natural, synthetic or a mixture of natural and synthetic zeolite in the removal of ammonia from aqueous medium.
Ammonia Removal from Aqueous Medium Using Zeolite
Ammonia Absorption:
The absorption of ammonia from an aqueous medium is effected by causing contact between the aqueous medium and zeolite. During the contact period, ammonia in the aqueous medium absorbs onto the zeolite and is effectively removed from the aqueous medium. The zeolite at this point is considered “loaded” with ammonia.
There are two series of chemical reactions believed to occur in the absorption of ammonia to the zeolite. The first series of reactions occurs when the fresh zeolite is initially loaded into an absorption column (see below). The second series of reactions occurs after the zeolite has been migrated through the absorption process, including the elution step. The initial reactions result from the fact that natural zeolite is loaded with sodium ions, the second series of reactions results from the addition of alkaline (basic) material to the system. The alkaline material can be calcium oxide, “calcium based,” sodium hydroxide, “sodium-based,” or potassium hydroxide, “potassium based.” It is envisioned that other alkaline metals could be used in this context, for example, lithium, rubidium and cesium, but all are less preferable due to economic reasons. The two series of reactions are shown below with regard to a “calcium-based” system:
Initial Loading on Zeolite:

Ca+++NaZeol→2Na++CaZeol

2NH4++Na2Zeol→2Na+(NH4)2Zeol

2K++Na2Zeol→2Na++K2Zeol

Equilibrium Loading on Zeolite:

2NH4++Ca2Zeol→Ca+++(NH4)2Zeol

2K++Ca2Zeol→Ca+++K2Zeol

Ammonia Elution:

The ammonia, once loaded onto the zeolite, is passed from the absorption process to an elution unit process. The elution unit process (see below) functions to remove the ammonia absorbed to the zeolite. This is generally accomplished by contacting the loaded zeolite with a salt solution, or brine. The brine is typically composed of sodium, calcium, potassium, and/or magnesium ions in solution. The contact between the loaded zeolite and the brine causes ion displacement between the salt ions and the ammonia, thereby removing the ammonia from the zeolite and creating a “pregnant” brine solution relative to the concentration of ammonia. The chemical reactions of the elution step are illustrated below:

(NH4)2Zeol+Ca++→2NH4++Ca2Zeol

K2Zeol+Ca++→2K+Ca2Zeol

The elution step is in effect the reversal of the reactions discussed with respect to the absorption step above and is driven by the high concentration of salt ions in the brine solution relative to the concentration of ammonia.
Ammonia Dissociation from Brine:
The pregnant brine is fed to an air stripping unit process where the ammonia is dissociated from the brine. Generally, the pH in the pregnant brine is increased to a range of approximately 10 to 11 prior to contact with the air to facilitate the stripping process. In a preferred embodiment of the present invention, the pH is increased by the addition of lime to the brine. The lime helps to dissociate the ammonia from the brine in the form of ammonium hydroxide.
In the air stripping process, contact between air bubbles and loaded brine cause the diffusion of the ammonia from the brine to the air in the form of ammonia gas. The ammonia dissociation reaction steps that occur in the air stripping process are as follows:

2NH4++2Cl−+CaO+H2O→CaCl2+2NH4OH

2NH4OH→2NH3+2H2O

The air/ammonia mixture is then transferred to an air scrubbing step.
Acid Wash to form Ammonium Salt:
The air/ammonia mixture is treated with an acid wash to form an ammonium salt. Preferably, the air is treated with a sulfuric acid (H2SO4), or other like acid, wash via the following reaction:

2NH3+H2SO4→(NH4)2SO4 

Note that the air can preferably be re-circulated in the air stripper.
Storage and Destruction of Ammonium Salt
The ammonium sulfate is passed to a storage tank, or to a re-circulation tank, for ultimate disposal. Ammonium sulfate, in one embodiment of the present invention, is removed from the storage tank and supplied for use in fertilizer and other commercial purpose. However, it has been determined that disposal through these uses can be of marginal economic advantage due to the relatively low concentration of the ammonium sulfate. As such, other embodiments of the present invention are envisioned for the disposal of the ammonium salt, preferably via the destruction of the ammonia through combustion.
Combustion of Ammonia:
The ammonium sulfate in the storage tank is mixed with a basic material, such as lime or other like agent, and passed to an air stripping unit similar to the one described above. The ammonium sulfate stream is reacted with lime to dissociate the ammonia in the form of ammonium hydroxide and facilitate air stripping. The ammonium hydroxide is then removed from the solution as ammonia gas by contacting the solution with a flow of air. The ammonia gas is passed to a combustion unit to be burned at a controlled temperature to avoid the production of NOx gases.
Typically, the combustion unit is heated by natural gas and includes various streams available to vary the composition of the ammonia gas mixture for ideal combustion. For example, where the concentration of the ammonia gas in air is too high, e.g., greater than 1.1% by weight ammonia in the gas stream, the ammonia gas stream is diluted with air. Where the concentration of the ammonia in the air is too low, e.g., less than 1.1% by weight ammonia in the gas stream, the ammonia gas stream is combined with a combustion gas supply to facilitate combustion (increasing the temperature of the stream).
If required, the combustion air supply can be a mixture of burner gas and air that is burned in a pre-burner prior to entering the combustion chamber of the present invention. The exhaust gas from the pre-burner is fed to the combustion unit to raise the temperature of the combustion step to the required level, i.e., the temperature required to combust the concentration of ammonia gas in the gas stream.
Preferably, the concentration of ammonium sulfate fed to the destruction process is in the range of about 20% to about 40% by volume. If the ammonium sulfate is not at this concentration, it is fed to a recirculation tank where the ammonium sulfate is re-circulated through the acid scrubbing process and bled in increments to the destruction process (when the appropriate concentration is reached). The following chemical reactions are believed to occur during the combustion unit process:

(NH4)2SO4+CaO+3H2O→2NH4OH+CaSO4H2O

2NH4OH→2NH3+2H2O

CH4++4NH3+3O2+N2→8H2O+N2+CO2 

Zeolite Flow:

The zeolite for use in the present invention is input into the process at the ammonia absorption step. Typically an appropriate amount of zeolite is charged into a housing member(s), e.g., tank, column, etc, for contact with the aqueous medium. The zeolite is maintained within the absorption step and contacted with the aqueous medium for an amount of time sufficient to decrease the concentration of ammonia from a first level (in the feed of the aqueous medium) to a second level (in the discharge of the aqueous medium). In preferred embodiments the discharge level is less than the acceptable discharge limits for ammonia as set by the Environmental Protection Agency (EPA).
Loaded zeolite passes from the absorption step to the stripping unit process (see above), where the ammonia is eluted from the zeolite. The zeolite is passed from the elution process to a rinse unit where the zeolite is cleaned for re-circulation back to the absorption step. In the rinse step, the zeolite stream is fed to a rinse column where it is rinsed with water. Note that the rinse step can include a reverse osmosis unit where chemicals contained in the rinse stream, including calcium, chloride, sulfate, hydroxide, and carbonate are recovered. The recovery of these chemicals helps defray the overall operation costs, as the chemicals can be re-used. Note also that the reverse osmosis unit lowers the pH and total dissolved solids (TDS) content of the discharge stream.
Once refreshed/regenerated, the zeolite is pumped back to the absorption step and the absorption process repeated. It is believed that the zeolite can be re-used in this manner for an indefinite period of time. However, degradation of the zeolite does occur over time, and degraded zeolite is removed or purged from the system by passing it through with the discharge stream. As such, a fairly predictable amount of zeolite must be added to the absorption process to keep a fairly constant amount of zeolite in the system (typically equal to the amount of degraded zeolite purged from the system).
Embodiments of the present invention will now be described with reference to the following Figures.
FIG. 1 provides a process diagram or schematic 100 of ammonia removal and destruction in accordance with the present invention. Aqueous medium 102 is feed into the absorption step 104 (ion exchange). The ammonia is removed from the aqueous medium, which is discharged having a discharge level of ammonia 106. The ammonia loaded zeolite is next treated with brine in an elution step 108 to release ammonia. The zeolite is recovered in a rinse step 110 and cleaned for re-use in the absorption step (as shown by line 112). The ammonia/brine solution is treated with an air strip step 114 and an acid scrubbing step 116 as described above, for ultimate storage 118 and use, or storage/re-circulation to increase the ammonia concentration for ultimate destruction 120.
FIG. 2 is a schematic diagram 200 of an absorption unit process according to one embodiment of the present invention. In this embodiment, three absorption columns 202, 204, and 206 are provided for contact between the zeolite and aqueous medium. The aqueous medium 208 is fed up-flow through the first absorption column 202, into the second absorption column 204, and into a third absorption column 206, and then discharged from the system 210. The absorption columns can be operated as fixed bed, fluidized bed, or as stirred reactors. Most preferably, the columns are operated as fluidized bed.
The aqueous medium 208 is fed to the absorption tanks at a flow rate such that the zeolite (generally in the form of a slurry) is fluidized in the columns. For example, it has been determined that an aqueous medium having an up-flow rate of 10 gal/ft2 is sufficient to fluidize a bed of zeolite comprising 20×40 mesh zeolite, resulting in between a 40% and 45% expansion of the zeolite. The up-flow configuration creating a fluidized bed is preferred because there is a decreased likelihood of bio-fouling of the columns, the equipment tends not to short-circuit as often, and the configuration allows the degraded zeolite to be discharged from the system with the aqueous medium.
In one particular embodiment of the present invention, the zeolite is migrated through the absorption process in a counter-current flow configuration 212 (see FIGS. 2 and 4). Here the aqueous medium with the strongest concentration of ammonia contacts zeolite that is already partially loaded, and fresh or stripped zeolite contacts the aqueous medium at a point where the concentration of ammonia is decreased. The configuration creates favorable conditions for obtaining a low ammonia content in the discharge and efficient loading of the ammonia on the zeolite.
Referring again to FIG. 2, the zeolite is passed from an elution step 214 to a rinse step 216, where the zeolite is rinsed clean with water or other like solution. The migration of the zeolite is accomplished through methods such as air-lifting or by positive displacement pumps. Air lifts are generally known technology which use compressed air to raise the zeolite in the absorption column by introducing compressed air into the zeolite near the bottom of the absorption column. The air mixes with the fluidized zeolite near the bottom of the column and causes the overall level of zeolite to rise thereby spilling over the top of the column, where the zeolite is collected and fed to the next column. In this manner the zeolite is continuously being transferred from column to column to column to rinse step back to the first column again. Note that the number of absorption columns can be varied with regard to the present invention, and is dependent on the capacity required by the overall system.
FIG. 3 provides a schematic diagram 300 of the destruction process in accordance with one embodiment of the present invention. In this embodiment, the storage tank 302 housing the ammonium sulfate feeds a stream of material (see line 304) to the ammonia recovery step 306, where an ammonia gas is fed 308 to a combustion 310 unit for destruction of the ammonia. In preferred embodiments, a pre-burner 312 is provided to ensure that lower concentrations of ammonia gas can be destroyed. Note also the lime storage tank 314 for ammonia recovery.
Referring to FIG. 4, a process diagram is shown of a preferred embodiment where four absorption columns 402 operating as fluidized beds and having the zeolite migrated counter-current to the flow of aqueous medium is shown. Note that a brine elution step and a rinse step, with a reverse osmosis unit, are provided to reclaim or recover useful chemicals (see below for additional detail). A destruction unit process, comprising an air stripping unit process and a combustion unit process, are also shown. Also note that the ammonium sulfate is stored in a re-circulation tank.
In more detail, the absorption columns 402 are charged with zeolite, preferably a natural zeolite, more preferably clinoptilolite, for contact with an aqueous medium. The aqueous medium feed 404, having a first level of ammonia, is pumped up-flow, via pump 406, to the first absorption tank at a sufficient flow rate to fluidize the zeolite (target of 40% to 45% expansion). The aqueous medium is then pumped from the first column through the remaining columns in an up-flow configuration utilizing pumps 408. As in column one, the flow rate should be sufficient to fluidize the zeolite in the remaining columns. The aqueous medium, now having a second level of ammonia, is discharged from the system as a discharge stream 410. The second level or discharge level of ammonia is preferably below the acceptable discharge limits as set by the EPA and is most preferably at a concentration of less than 1 mg/L.
The zeolite in the absorption system is pumped in a counter-current configuration to the flow of the aqueous medium. The fresh zeolite stream 412 enters the fourth absorption column first, by passing through a screen 414 provided for the conservation of material and minimization of TDS in the discharge. The zeolite in the absorption columns migrates from column four, to column three, to column two, to column one, and then to the elution step. Preferably, the zeolite is moved using air lifts, which are generally known in the art. The rate of migration is selected such that the contacting time with the aqueous medium is sufficient to produce an aqueous medium having a concentration of ammonia (second level) in the discharge stream 410 lower than the discharge limits set by the EPA. The zeolite stream exiting the first absorption tank is loaded with ammonia and becomes the loaded zeolite stream 416 fed to the elution column 418.
In the elution step, the loaded zeolite stream 416 is contacted in an elution column 418 with a lime input stream 420 and an eluant stream 422. The amount of lime, as stored in a lime storage tank 424, added to the elution column is determined such that the alkalinity of the brine solution is sufficient to remove nearly 100% of the ammonia from the loaded zeolite (this goes for the amount of time as well). The stripped zeolite exits the elution column, passes through a screen 426, and becomes the stripped zeolite feed 428 for the rinse process. The pregnant brine, or eluant stream 430, is fed to the air stripping unit 432.
With regard to the zeolite rinse process, the stripped zeolite stream 428 is rinsed with a rinse stream 434 in a rinse column 436. The rinse process may or may not include a reverse osmosis unit 438 depending on the discharge limits of various chemicals (if the discharge limits are low, it may be a requirement to install a reverse osmosis unit), such as chloride, and on the economic feasibility to recovering the chemicals.
The rinse stream 434 is preferably comprised of a water stream 440 and a reverse osmosis unit permeate 442. The reverse osmosis permeate 442 is created by the passage of the rinse stream 434 exiting the rinse column 436 through a reverse osmosis unit 438. The reverse osmosis concentrate 444 generally contains recovered chemicals such as calcium, chloride, sulfate, and carbonate, and is fed back into the elution column 418.
The zeolite stream exiting 428 the rinse column 436 is fed back to the fourth absorption column as regenerated zeolite 412. A difference between the stripped zeolite and newly loaded zeolite loaded into the columns 402 is that the regenerated zeolite has calcium ions absorbed thereto as opposed to sodium ions.
Referring again to the air stripping unit, a slurry containing the pregnant eluant 430 is mixed with lime 420 to a stripping column 432. An air feed stream 446 is added to the stripping column to facilitate the removal of the ammonia from the slurry 430, thereby creating a mixture of air and ammonia gas.
The air/ammonia mixture stream 448 is fed from the stripping column 432 to an air scrubbing unit 450 where it is washed with a scrubbing acid stream 452. The scrubbing acid stream 452 is created by an acid stream 454 mixed with an amount of product scrub stream 456 from the re-circulation tank 458. The scrubbing acid is preferably H2SO4 stored in a acid storage tank 460. Note that the scrubbing acid removes ammonia from the air/ammonia mixture and creates an ammonium sulfate solution. The ammonium sulfate solution is removed from the air scrubbing column 450 as the product scrub stream 456 and is transferred to the re-circulating tank 458. The scrubbing stream 452 contains an amount of the product scrub stream 456 as recycle. This recycle, coupled with the low percentage bleed of the product scrub stream 456 acts as a concentrator of ammonium sulfate. The concentration of this stream is a factor in the efficient combustion of the ammonia in the destruction process.
The ammonium sulfate in the re-circulating tank 458 is bled to a mixing tank 462 via stream line 464 for destruction. The amount of ammonium sulfate bled through line 464 is preferably less than 20% of the flow rate circulating between the re-circulation tank 458 and the air scrubber unit process. The ammonium sulfate solution is mixed in the mixing tank 462 with an amount of alkaline material, preferably lime, present in steam 466. The lime or other alkaline material is stored in alkaline storage tank 468. The lime is added to the ammonium sulfate to dissociate the ammonia from the hydroxide. This reaction also produces calcium sulfate (CaSO4), or gypsum, which is preferably removed by passing the product through a filter (not shown).
In certain applications, where the gypsum in the mixing tank becomes very thick in consistency, dilution water 470 may be added. The filter separates out a gypsum cake from a filtrate 472 comprising ammonium hydroxide. The filtrate 472 is fed to an additional air stripping column 474 where it is contacted with an air stream 476 thereby removing the ammonia from the filtrate 472. The remaining liquid stream contains a relatively low concentration of remaining ammonia and can be bled from the air stripper back to the feed stream 404 (see line 478), or other low or non-ammonia containing waste disposal tank (not shown).
The ammonia containing air stream 480 exiting the air stripping column 474 is passed to a combustion unit 482. Depending on the concentration in the air stream, a dilution air stream 484 (to reduce combustion temperature) or a combustion air stream 486 (to increase combustion temperature) can be added to the combustion unit to facilitate combustion of the ammonia. The combustion air stream is blended with a methane stream 488 and passed to a pre-bumer (not shown) if necessary. The combustion reaction produces water vapor, nitrogen, and carbon dioxide. The products 490 of the combustion reaction are discharged into the atmosphere.
An alternative of the combustion air stream is to use a catalytic combustion device, for example, catalyst sold by CSM Worldwide, Inc., located at 200 Sheffield St., Mountainside, N.J. 07092. The catalyst would be used to facilitate the combustion of the ammonia in the combustion chamber.
FIGS. 5A, A2, B, B2, C1 and C2 show a theoretical mass balance calculation for the process schematic discussed in FIG. 4. The process requirements including flow rates, concentrations of streams, size of columns, and any other process conditions as were determined through the experimental procedures discussed in detail in the Examples which follow. Specifically, the test results shown in the Examples below were used to estimate the design process condition and assumption based in FIGS. 5A–C2. Additionally, several assumptions were made with respect to process conditions, for example, a theoretical one million gallon per day facility was used as the target facility.
Systems for Monitoring and Disposing of Ammonia From an Aqueous Medium
The present invention contemplates a system for operating the equipment required to remove ammonia from a target water source by an off-site provider, for example a company that specifically installs, monitors, trouble-shoots, and replaces the zeolite materials in the tanks/columns of the present invention. The off-site provider is contemplated to be hired by a municipality (or other like governmental or private water board) to maintain the ammonia levels in the municipalities water via the systems and methods of the present invention. The off-site provider is responsible for determining the ammonia removal requirements of the target water source, for example a water treatment facility, including the type and amount of zeolite required, the number of tanks necessary to house the zeolite, the design of the flow through the tanks, i.e., up-flow, down-flow or batch, the flow rate of the aqueous medium, the length of time before replacement of zeolite, the chemical components and amounts required for efficient removal and destruction of the ammonia, and the combustion requirements of the ammonia removal system, etc.
The off-site provider installs the properly charged zeolite materials at the water treatment facility and monitors the first level, second level, discharge level, etc of the ammonia in the water, and of the ammonia levels during the combustion process (note that the ammonia may be stored as an ammonium salt, which may also be controlled by the off-site provider). The ammonia monitoring can be technician based, i.e., a technician goes to the installed system and takes a sample for analysis, or can be performed by a pre-programmed monitoring unit that removes and analyzes a sample, and transmits the ammonia levels to an off-site monitoring unit, for example a computer via a wireless communication unit. The off-site monitoring unit can be equipped with a signaling means for alerting the off-site provider of over target ammonia levels for discharge, as well as for the levels of the zeolite in the system and the concentration of ammonia gas for combustion in the combustion unit. In one embodiment, the off-site provider has the capability of adding fresh zeolite to the absorption tanks when it is evident that the capacity of the system is insufficient for removing the requisite amount of ammonia.
The off-site provider is responsible for coordinating any maintenance or trouble-shooting issues that arise during the ammonia removal and destruction process. As such, alarms or other signaling devices may be included in the zeolite housing members or other units (air stripping, scrubbing, etc) to alert the provider of a potential malfunction in the system. Further, the off-site manager is responsible for the replacement of degraded zeolite.
The off-site provider installs the properly charged zeolite materials at the water treatment facility and monitors the first level, second level, discharge level, etc of the ammonia in the water, and of the concentration and chemical form of the ammonia during the storage and/or destruction process. As noted above, the ammonia monitoring can be technician based, i.e., a technician goes to the installed system and takes samples for analysis, or can be performed by a pre-programmed device that incrementally removes samples for analysis of ammonia levels, data being transmitted automatically to an off-site monitoring unit, for example a computer. The off-site monitoring unit can be equipped with a signaling means for alerting the off-site provider of over target ammonium levels for the discharge level, as well as for ammonium levels that are problematic during the combustion process, so that modifications can be made where appropriate.
The off-site provider is responsible for coordinating any maintenance or trouble-shooting issues that arise during the ammonia removal process, including the ordering and delivery of appropriate chemicals, for example lime, H2SO4, brine, etc. As such, alarms or other signaling devices may be included in the chemical component storage vessels, stream lines, etc, to alert the provider of a potential malfunction or shortcoming in the chemical storage or delivery.
As such, an off-site provider of the present invention can be hired by a third party (municipal water board, private water rights holder, etc.) to independently operate the ammonia removal and destruction system disclosed herein. In one embodiment, the off-site provider is an independent contractor specializing in the systems and methods of the present invention. In preferred embodiments, the off-site provider operates a plurality of ammonia removal and destruction systems at a number of geographically different sites for a number of different third parties.
In another embodiment, the off-site provider compiles data from its different sites to optimize the removal of ammonia and destruction of ammonia at those sites, i.e., data is compiled and compared, and optimized systems and methods developed. The data includes the basic parameters for operating the different embodiments of the invention, amounts of zeolite, flow rate concentration of brine, etc.
Finally, the systems and methods of the present invention provide business advantages for an off-site provider to remove and destroy ammonia from public or private water supplies, as managed by other third parties. The business methods provide economic and technological advantages to the third party for removing and destroying ammonia, as described by the embodiments of the present invention.
Having generally described the invention, the same will be more readily understood by reference to the following examples, which are provided by way of illustration and are not intended as limiting.
EXAMPLES
Example 1
Sodium Zeolite Absorption of De-mineralized Water/Ammonia Feed
Tables 2 and 3 show the results of ammonia absorption from an aqueous medium by two columns connected in series charged with regenerated sodium chloride zeolite. The feed solution was prepared using de-mineralized water and adding approximately 28 mg/L ammonia thereto. The feed solution was pumped in an up-flow configuration at a flow rate of approximately 1.5 liters per min (L/min).
The data shown in Table 2 shows that the concentration of ammonia in the effluent of column one began at 0.06 mg/L and concluded at 20.6 mg/L. The effluent exiting column two began at 0.03 mg/L and remained below the discharge level (1 mg/L ammonia) for about 450 minutes. At the completion of the test, the ammonia concentration in the effluent of column 2 was 8.1 mg/L. These results suggest that at the selected flow rate, an additional column of charged zeolite is necessary to ensure that the ammonia concentration in the effluent or discharge stream is at a level lower than the standard discharge level as set by the EPA (approximately 1 mg/L).







TABLE 2







Ammonia removal from two columns connected in series












Col. 1 Effluent

Col. 2 Effluent




















Flow
Bed
Feed

NH3
meq
meq
NH3
meq
meq on
%


Time
rate
Vol.
NH3
meq NH3
mg/L
dischar.
on zeol.
mg/L
disch.
zeol.
rec.





















0
1.5
0
28.5
0
0.06
0
0
0.03
0
0



10
1.5
6
28.5
30.54
0.06
0.064
30.47
0.03
0.03
0.03
99.9


105
1.5
63
27.2
307.39
0.83
8.51
298.88
0.12
1.25
7.26
99.6


265
1.5
159
23.1
703.39
5.9
109.66
593.74
0.14
3.65
106.00
99.5


435
1.5
261
24.4
1147.82
10.5
300.91
846.92
0.77
17.68
283.23
98.5


450
1.8
324
18.2
1182.92
5.2
310.93
871.99
0.41
18.47
292.46
98.4


560
1.8
403.2
27.9
1577.51
15.8
534.39
1043.12
1.24
36.01
498.38
97.7


680
1.8
489.6
27.4
2000.25
19.7
838.33
1161.
3.38
88.16
750.18
95.6


800
1.8
576
28
2432.25
20.6
1156.2
1276.1
8.1
213.13
943.04
91.2









Table 3 summarizes the test data with regard to bed volumes and meq/g for columns one and two:







TABLE 3







Ammonia Concentration For Columns One and Two









Bed Volume
meq/g for Col. 1
meq/g for Col. 2












0
0.0
0.0


6
0.018
0.0


63
0.173
0.004


159
0.343
0.059


261
0.490
0.158


324
0.504
0.163


403
0.603
0.278


490
0.672
0.418


576
0.738
0.525









A second test was performed using similar parameters, except that the flow rate for the aqueous medium was 1.7 L/min and the initial concentration of ammonia in the feed was 37.4 mg/L. Again the results, as shown in Tables 4 and 5, were similar to the data in Tables 2 and 3, where the concentration of ammonia in the effluent at the end of the test exceeded the discharge limit of 1 mg/L (suggesting a third column would be desirable). However, as above, the data indicates the utility of zeolite in removing ammonia from an aqueous medium.







TABLE 4







Ammonia removal from two columns connected in series (1.7 L/min flow rate)












Col. 1 Effluent

Col. 2 Effluent




















Flow
Bed
Feed
meq
NH3
meq
meq on
NH3
meq
meq on
%


Time
rate
Vol.
NH3
NH3
mg/L
dischar.
zeol.
mg/L
dischar.
zeol.
rec.





















0
1.7
0
37.4
0
1.19
0
0
2.54
0
0
0


20
1.7
13.6
37.4
90.83
1.19
2.89
87.94
2.54
6.17
−3.2
93.2


85
1.7
57.8
35.9
374.18
1.1
11.57
362.61
0.37
9.09
2.48
97.6


145
1.7
98.6
36.2
637.93
2.92
32.85
605.08
0.41
12.08
20.77
98.1


265
1.7
180.2
31.1
1091.1
11.1
194.59
896.51
0.34
17.03
177.56
98.4


375
1.7
255
33.3
1535.89
21.9
487.11
1048.78
0.73
26.78
460.33
98.3


505
1.7
343.4
36.9
2118.38
26.1
899.12
1219.26
2.32
63.40
835.71
97.0


565
1.7
384.2
31.6
2348.61
26
1088.55
1260.06
5.5
103.48
985.07
95.6
















TABLE 5







summarizes the test data with regard to bed volumes and meq/g for


columns one and two (1.7 L/min flow rate):









Bed Volumes
meq/g for Col. 1
meq/g for Col. 2












0
0
0


14
0.051
0


58
0.210
0.001


99
0.350
0.012


180
0.519
0.099


255
0.607
0.256


343
0.705
0.466


384
0.729
0.549









Example 2
Sodium Zeolite Absorption of High Ammonia Feed Containing Calcium, Magnesium and Potassium
Tables 6 and 7 illustrate that aqueous medium containing approximately 26.5 mg/L ammonia, 127 mg/L calcium, 36 mg/L magnesium, 31 mg/L potassium, and 8.8 mg/L sodium, can be effectively treated to remove ammonia using the apparatus and methods of the present invention. The aqueous medium was pumped up-flow through a two column system similar to the one described in Example 1. The solution was pumped at a flow rate of approximately 1.7 L/min for a total time of 435 minutes.
Tables 6 and 7 show that the concentration of ammonia in the column one effluent was approximately 20.9 mg/L and the concentration in the column two effluent was approximately 16.4 mg/L. As in Example 1, an additional column would have been useful for a more complete removal of the ammonia from the solution at that flow rate. The data also illustrates that calcium loads quickly onto the zeolite and that the majority of the sodium on the zeolite prior to flow of the solution is displaced by calcium and ammonia (see FIG. 6). Note that the concentration of sodium clearly decreases from an initial concentration of greater than 200 mg/L to a concentration of less than 50 mg/L, while the concentration of calcium increases from an initial concentration of less than 25 mg/L to a concentration of greater than 100 mg/L.







TABLE 6







Ammonia Loading onto Two Column Zeolite System - Col 1 Effluent









Col. 1 Effluent




















Flow
Bed
meq fed
meq
meq
meq
meq
meq NH3
meq NH3
meq disch
meq disch
meq disch


Time
rate
Vol.
NH3
fed Ca
fed Mg
fed K
fed Na
disch.
on C#1
Ca
Mg
K





0
1.7
151
0
0
0
0
0
0
0
0
0
0


15
1.7
151
47.9
161.9
75.9
20.2
9.4
4.0
43.9
25.5
23.2
0.65


75
1.7
151
240.96
814.7
387.8
101.1
48
72.2
168.8
392.7
301.4
13.70


135
1.7
151
433.32
1472.6
708.1
179.3
87.5
183.6
249.7
877.2
613.26
39.78


195
1.7
151
621.29
2135.6
1036.9
257.6
127.8
319.2
302.1
1428
950.45
74.70


255
1.7
151
810.72
2788.4
1348.8
335.9
167.7
502.8
307.9
2009.4
1287.65
112.83


315
1.7
151
1000.1
3431.0
1652.2
414.1
207.2
663.8
336.4
2575.5
1591.12
157.17


375
1.7
151
1198.32
4063.4
1947.3
492.4
246.2
802.9
395.4
3162
1903.02
204.13


435
1.7
151
1405.96
4695.8
2242.3
570.7
284.8
955.2
450.8
3743.4
2206.49
253.70















C#1
C #2
bed
elapsed

Col 1 effluent mg/L



















wt
wt
vol.
time
NH3
feed Ca
feed Mg
feed K
feed Na
NH3
Ca
Mg
K





1729
1795
0
0
26.3
127
36
31
8.5
2.22
20
11
1


1729
1795
10.2
15
26.3
127
36
31
8.5
2.22
20
11
1


1729
1795
51
75
26.5
128
37
31
8.7
9.35
72
33
5


1729
1795
91.8
135
26.4
129
38
30
8.9
15.3
95
37
10


1729
1795
132.6
195
25.8
130
39
30
9.1
18.6
108
40
13


1729
1795
173.4
255
26
128
37
30
9.2
5.2
114
40
15


1729
1795
214.2
315
26
126
36
30
8.9
22.1
111
36
17


1729
1795
255
375
27.2
124
35
30
8.8
19.1
115
37
18


1729
1795
295.8
435
28.5
124
35
30
8.7
20.9
114
36
19





total eq
26.56
127
36.56
30.33
8.79





12.08
1.56
6.35
3.00
0.78
0.38










Ammonia Loading onto Two Column Zeolite System - Col 2 Effluent









Column 2 Effluent




















Flow
Bed
meq
meq
meq NH3
meq
meq
meq
meq
meq Ca
meq Mg
meq K


Time
rate
Vol.
Na
dischar
on Col 2
Ca
Mg
K
Na
on Col. 1
on Col. 1
on Col. 1





0
1.7
151
0
0
0
0
0
0
0
0
0
0


15
1.7
151
257.2
2.4
1.64
0.54
0.25
0.65
266.09
136.43
52.69
19.57


75
1.7
151
740.6
12.46
59.71
66.84
135.13
0.91
1148.61
422.03
86.41
87.39


135
1.7
151
1046.6
31.62
152.01
306.54
447.03
6.13
1734.0
595.43
94.84
139.57


195
1.7
151
1268.3
80.43
238.72
658.44
801.08
13.96
2221.83
707.63
86.41
183.91


255
1.7
151
1459.0
154.75
348.01
091.94
1146.7
27
2603.22
779.03
61.12
223.04


315
1.7
151
1618.7
251.65
412.12
1556.04
1458.6
42.65
2926.96
855.53
61.12
256.96


375
1.7
151
1756.2
355.11
447.82
2055.84
1770.5
63.52
3193.04
901.43
44.26
288.26


435
1.7
151
1871.5
474.59
480.62
586.24
2082.40
89.61
3414.78
952.43
35.83
316.96












Col 2 Effluent, mg/L

















Time
Flow rate
Bed Vol.
Na
NH3
Ca
Mg
K
Na







0
1.7
151
232
1.32
0.42
0.12
1
240



15
1.7
151
232
1.32
0.42
0.12
1
240



75
1.7
151
109
1.38
13
16
0.1
199



135
1.7
151
69
2.63
47
37
2
132



195
1.7
151
50
6.7
69
42
3
110



255
1.7
151
43
10.2
85
41
5
86



315
1.7
151
36
13.3
91
37
6
73



375
1.7
151
31
14.2
98
37
8
60



435
1.7
151
26
16.4
104
37
10
50

















TABLE 7







Summary of Loading and Effluent onto Columns One and Two













bed vol
NH3
Ca
Mg
K
Na
Sum










Column 1 - Loading on Zeolite, meq/g













0
0.000
0.000
0.000
0.000
0.000
0.000


10
0.025
0.079
0.030
0.011
−0.143
0.003


51
0.098
0.244
0.050
0.051
−0.401
0.042


92
0.144
0.344
0.055
0.081
−0.555
0.070


133
0.175
0.409
0.050
0.106
−0.660
0.081


173
0.178
0.451
0.035
0.129
−0.747
0.046


214
0.195
0.495
0.035
0.149
−0.816
0.057


255
0.229
0.521
0.026
0.167
−0.873
0.069


296
0.261
0.551
0.021
0.183
−0.918
0.098







Column 2 - Loading on Zeolite, meq/g













0
0.000
0.000
0.000
0.000
0.000
0.000


10
0.001
0.014
0.013
0.000
−0.005
0.023


51
0.033
0.182
0.093
0.007
−0.227
0.087


92
0.085
0.318
0.093
0.019
−0.383
0.131


133
0.133
0.429
0.083
0.033
−0.531
0.147


173
0.194
0.511
0.079
0.048
−0.637
0.194


214
0.230
0.568
0.074
0.064
−0.729
0.206


255
0.249
0.616
0.074
0.078
−0.800
0.217


296
0.268
0.645
0.069
0.091
−0.860
0.213







Column 1 - Effluent, mg/L













0
2.22
20
11
1
232



10
2.22
20
11
1
232


51
9.35
72
33
5
109


92
15.3
95
37
10
69


133
18.6
108
40
13
50


173
25.2
114
40
15
43


214
22.1
111
36
17
36


255
19.1
115
37
18
31


296
20.9
114
36
19
26







Column 2 Effluent, mg/L













0
1.32
0.42
0.12
1
240



10
1.32
0.42
0.12
1
240


51
1.38
13
16
0.1
199


92
2.63
47
37
2
132


133
6.70
69
42
2
110


173
10.2
85
41
3
86


214
13.3
91
37
5
73


255
14.2
98
37
6
60


296
16.4
104
37
8
50









The data in Example 2 illustrates the utility of the present invention for absorbing ammonia from an aqueous medium, in particular absorbing ammonia from an aqueous medium having a high concentration of calcium, sodium, potassium and magnesium.
Example 3
Sodium Zeolite Absorption of Ammonia from an Aqueous Medium Having High Concentrations of Calcium, Magnesium and Potassium
The data in Example 3 was prepared in a manner similar to that shown in Example 2, except that the flow rate through the two columns was approximately 1.5 L/min and the medium was run over the columns for a total of 430 minutes. As noted in Tables 8 and 9, the ammonium concentration of column one effluent was 19.7 mg/L, while the concentration of ammonium of column two was approximately 14.7 mg/L.
Note that the slightly decreased flow rate of the aqueous medium results in a higher absorption of ammonia by the zeolite as compared to the same ammonia loading performed in Example 2. Again, as described in Example 2, a third column of zeolite is required to keep the ammonia levels below 1 mg/L over the course of the experiment.







TABLE 8







Ammonia Loading onto Two Column Zeolite System - Col 1 Effluent (low flow)









Col 1




















Flow
Bed
meq fed
med feq
meq fed
meq
meq
meq disch
meq NH3
meq disch
meq disch
meq disch


Time
Rate
Vol.
NH3
Ca
Mg
fed K
fed Na
NH3
of Col 1
Ca
Mg
K





0
1.5
150.8
0
0
0
0
0
0
0
0
0
0


10
1.5
150.8
29.6
95.3
44.6
10.7
5.94
0.193
29.38
12.75
9.55
0.038


70
1.5
150.8
203.1
662.3
312.4
75.2
41.54
30.99
172.2
377.3
255
6.944


130
1.5
150.8
370.3
1224
580.2
141.9
77.54
110.7
259.6
845.3
522.8
23.06


190
1.5
150.8
534.2
1782
847.9
208.7
113.5
203.9
330.3
1349
798
46.07


250
1.5
150.8
698.1
2332
1123
275.5
148.8
306.8
391.4
1880
1081
75.99


310
1.5
150.8
861.4
2872
1405
342.2
182.8
437.3
424.2
2420
1363
112.8


370
1.5
150.8
1024
3407
1696
408.9
216.1
576.1
447.9
2965
1638
152


430
1.5
150.8
1187
3938
1986
475.7
248.2
702.8
483.9
3536
1921
193.4












Column 1 Effluent



















Col 1
Col 2
bed
Elap.
Feed
Feed
Feed
Feed
Feed
NH3
Ca
Mg
K


wt
wt
vol
Min.
NH3 mg/L
Ca mg/L
Mg mg/L
K mg/L
Na mg/L
mg/L
mg/L
mg/L
mg/L





1729
1795
0
0
27.6
127
36
28
9.1
0.18
17
7.7
0.1


1729
1795
6
10
27.6
127
36
28
9.1
0.18
17
7.7
0.1


1729
1795
42
70
27
126
36
28
9.1
4.79
81
33
3


1729
1795
78
130
26
125
36
29
9.2
12.4
104
36
7


1729
1795
114
190
25.5
124
36
29
9.2
14.5
112
37
10


1729
1795
150
250
25.5
122
37
29
9
16
118
38
13


1729
1795
186
310
25.4
120
38
29
8.7
20.3
120
38
16


1729
1795
222
370
25.3
119
39
29
8.5
21.6
121
37
17


1729
1795
258
430
25.3
118
39
29
8.2
19.7
127
38
18










Ammonia Loading onto Two Column Zeolite System - Col 2 Effluent (low flow)









Col 2




















meq





meq







meq Na
NH3
meq NH3
meq Ca
meq Mg
meq K
meq Na
Ca on
meq Mg
meq K
meq Na
meq Ca
meq Mg


disch
disch
on col 2
disch
disch
disch
disch
Col 1
on col 1
on col 1
on col 1
on col 2
on col 2





0
0
0
0
0
0
0
0
0
0
0
0
0


148.7
0.107
0.086
1.8
0.409
0.038
167.6
82.5
35.08
10.70
−142
10.95
9.136


571.3
0.750
30.24
136.8
186.4
2.230
883.7
285
57.4
68.25
−529
240.5
68.64


841.3
7.179
103.5
438.3
461.6
4.642
1369
379.5
57.4
118.8
−763
406.9
61.20


1053
25.37
178.5
825.3
744.2
9.246
1760
433.5
49.96
162.6
−939
523.9
53.76


1217
59.38
247.4
1266
1034
16.15
2085
451.5
42.52
199.5
−999
613.9
46.32


1350
126.2
311.0
1739
1310
27.7
2371
451.5
42.52
229.4
−999
681.5
53.76


1475
201.5
374.7
2238
1585
41.47
2609
442.5
57.34
257
−999
726.5
53.76


1582
296
406.8
2796
1860
59.89
2810
402
64.84
282.3
−999
740
61.20












Col 2 Effluent














Na mg/L
NH3 mg/L
Ca mg/L
Mg mg/L
K mg/L
Na mg/L







228
0.1
2.4
0.33
0.1
257



228
0.1
2.4
0.33
0.1
257



108
0.1
30
25
1
183



69
1
67
37
1
124



54
2.83
86
38
2
100



42
5.29
98
39
3
83



34
10.4
105
37
5
73



32
11.7
111
37
6
61



27.5
14.7
124
37
8
51.3

















TABLE 9







Summary of Loading and Effluent in Table 8













bed vol.
NH3
Ca
Mg
K
Na
Sum










Column 1 - Loading of zeolite, meq/g













0
0
0
0
0
0
0


6
0.017
0.048
0.02
0.006
−0.083
0.009


42
0.1
0.165
0.033
0.039
−0.306
0.031


78
0.15
0.219
0.033
0.069
−0.442
0.03


114
0.191
0.251
0.029
0.094
−0.543
0.022


150
0.226
0.261
0.025
0.115
−0.618
0.010


186
0.245
0.261
0.025
0.133
−0.675
−0.011


222
0.259
0.256
0.033
0.149
−0.728
−0.031


258
0.280
0.233
0.037
0.163
−0.772
−0.059







Column 2 - Loading on zeolite, meq/g













0
0
0
0
0
0
0


6
0
0.006
0.005
0
−0.011
0.001


42
0.017
0.134
0.038
0.003
−0.174
0.018


78
0.058
0.227
0.034
0.01
−0.294
0.035


114
0.099
0.292
0.03
0.021
−0.394
0.048


150
0.138
0.342
0.026
0.033
−0.484
0.055


186
0.173
0.380
0.03
0.047
−0.569
0.062


222
0.209
0.405
0.03
0.062
−0.632
0.073


258
0.227
0.412
0.034
0.074
−0.684
0.064







Column 1 - Effluent, mg/L













0
0.18
17
7.7
0.1
228



6
0.18
17
7.7
0.1
228


42
4.79
81
33
3
108


78
12.4
104
36
7
69


114
14.5
112
37
10
54


150
16
118
38
13
42


186
20.3
120
38
16
34


222
21.6
121
37
17
32


258
19.7
127
38
18
27.5







Column 2 - Effluent, mg/L













0
0.1
2.4
0.33
0.1
257



6
0.1
2.4
0.33
0.1
257


42
0.1
30
25
1
183


78
1
67
37
1
124


114
2.83
86
38
2
100


150
5.29
98
39
3
83


186
10.4
105
37
5
73


222
11.7
111
37
6
61


258
14.7
124
37
8
51.3









The data in Example 3 again illustrates the utility of the present invention. Zeolite absorbs ammonia from an aqueous medium with high affinity, even in the presence of high concentrations of calcium, magnesium, and potassium.
Example 4
Calcium Zeolite Absorption of Ammonia from an Aqueous Medium Having High Concentrations of Calcium, Magnesium and Potassium
The following Example illustrates that calcium treated zeolite provides an excellent column material for absorbing ammonia from an aqueous medium (see Table 10). One hundred grams of zeolite, 20×35 mesh, was contacted with a CaCl2 solution (20 grams dissolved into 1,000 ml demineralized water) overnight. The CaCl2 treated zeolite was moved to a column where fines and clays were removed and the zeolite weight determined.
A flow rate of 4 ml/min ammonia sample was passed over the zeolite column and samples of the column discharge taken every one hour (composite samples submitted for testing). A dissolved eluant containing 438 grams CaCl2 in 2000 mls demineralized water, pH of 10 (adjusted with NaOH) was used to elute zeolite at a solution flow rate of 5 ml/min. Discharged volumes were collected using the following formula: Z3-A=0–300 ml, Z3-B=300–600 ml, Z3-C=600–900 ml, Z3-D=900–1500, Z3-E=1500–2000 ml, Z3-E=1500–2000 ml.







TABLE 10







Calcium Form Zeolite Absorption of Ammonia












Analysis, mg/L
Zeolite loading, meq/g
NH3 grab
%





















ID
Day
Vol
Ca
Mg
K
Na
NH3
Ca
Mg
K
Na
NH3
feed/dis
Elu
























Z3
0
feed
97
22
34
.67
30.2









Z3
1
5010
41
.65
2.2
140
1.63
.14
.09
.04
−.3
.08
29.6/


Z3
2
4760
110
5.8
2.7
49
7.64
.11
.15
.08
−.4
.15
27.8/11.8


Z3
3
6450
90
13
3.2
16
17.2
.13
.2
.13
−.45
.186
27.8/21


Z3
4
4820
81
16
4.9
3.7
24.5
.17
.22
.17
−.45
.195
28.8/24.1







Began Elution





















−A
6
300
high
120
110
14
204

.19
.16
−.45
.16
/184
18


−B
6
300
high
29
110
.7
186

.19
.15
−.45
.13
/148
35


−C
6
300
high
23
96
4.3
166

.18
.14
−.46
.1
/186
50


−D
6
500
high
17
85
3.7
111

.17
.13
−.46
.065
/67
67


−E
6
500
high
13
76
3.7
67.7

.17
.12
−.46
.045
/59
77


−F
14
500
high
29
110
22
69

.16
.11
−.46
.025
/41
87


−G
14
500
high
5.7
110
61
32

.15
.09
−.47
.015
/32
92


−H
14
500
high
4.6
120
100
17

.15
.08
−.5
.01
/18
95







Second Cycle





















Z3
15
feed
92
26
38
45
51.7





/5.5



Z3
15
4860
180
.5
9
31
22.3
−.2
.1
.04
.03
.08
47.6/


Z3
16
6900
140
5
11
56
29
−.38
.22
.08
0
.16
41.7/32.4


Z3
17
6350
110
17
13
56
34.4
−.44
.27
.12
−.03
.19
41.3/36.6


Z3
20
9999
108
18
19
60
36
−.6
.39
.22
−.16
.25
39.1/33.8


Z3
21
1500
79
18
23
54
36.6
−.6
.4
.22
−.16
.25
37.7/33.3







Began Elution −45° C.





















−F

300

170
490
420
276

.36
.18
−.22
.2

20


−G

340

36
660
200
282

.35
.13
−.25
.143

42


−H

260

22
540
140
172

.34
.09
−.26
.117

53


−I

470

14
390
130
102

.33
.04
−.29
.089

64


−J

300

9
330
140
51

.33
.02
−.31
.08

68


−K

570

6.3
230
130
37

.33
−.01
−.34
.07

73


−L

580

3.1
180
120
15

.33
−.04
−.37
.062

75


−M

590

2.4
160
130
15

.33
−.07
−.40
.057

77









Table 11 illustrates a second test as above, however, the zeolite was eluted using a calcium concentration of 34.3 g/L. Sample IDs are the same as above, and assume 5 ppm NH3 blank on strip.







TABLE 11







Calcium Form Zeolite Absorption of Ammonia










NH3













Analysis, mg/L
Zeolite Loading, meq/g
Feed/
NH3





















ID
Day
Vol
Ca
Mg
K
Na
NH3
Ca
Mg
K
Na
NH3
Dis
Elut
























Z5
wash
350
12000
1.6
28
40
7

.325
−.07
−.4
0.6






feed
92
37
34
54
34

0
0
0
.01
34/



1
6050
190
2
8.2
38
7.6
−.3
.17
.04
.04
.1
33.3/



2
6450
140
21
8
53
18.2
−.4
.26
.08
.04
.16
32.7/



3
6400
110
29
8.9
54
28
−.5
.3
.12
.04
.18
33.4/



4
6100
110
31
9.6
58
30.4
−.6
.33
.16
.03
.19
32.7/31



wash
200
64
19
5.8
34
23.6


−H

recyl
15000
20
240
120




strip


−A
4
300
9500
230
47
220
76

0.28
0.18
0.02
0.177
/95
7


−B

300
14000
590
100
200
98

0.27
0.19
0.01
0.161
/102
15


−C

300
14000
42
100
160
87

0.26
0.2
0.01
0.146

23


−D
6
500
15000
76
130
150
81

0.24
0.21
0
0.124
/80
35


−E

500
15000
39
140
130
71

0.23
0.23
0
0.1
/73
45


−F

500
15000
29
150
120
52

0.23
0.24
0
0.09
/43
52


−G
8
500
15000
37
150
120
42

0.22
0.25
0
0.08
/34
58


−I

500
15000
12
78
100
39

0.23
0.27
0
0.07

63


−J

500
14000
11
83
100
18

0.23
0.29
0.01
0.07

65


−K

960
15000
11
110
110
20

0.24
0.32
0.01
0.06

70


−L
wash
300
5900
10
50
52
0.24

0.32
0.01







Second cycle





















Z5

feed
69
23
28
42
43.9





43.9/




10
6150
140
3.6
15
30
16.8
−.2
.33
.34
.04
.16
45.8/



11
6600
94
18
25
52
30.2
−.3
.36
.35
.01
.22
44.9/



15
6150
86
20
24
48
29.2
−.4
.38
.35
−.01
.27
44.8/31



16
6150
71
23
23
51
34.3
−.4
.38
.36
−.03
.31
44.4/32












Elution
recy
15000
11
120
110



strip





















−II
42 g/l
310

17
200
250
182

.38
.34

.26

16


−JJ
CaCl2
410

27
190
160
171

.37
.33

.22

30


−KK

280

20
180
120
146

.37
.33

.2

37


−LL

300

18
170
110
149

.37
.32

.17

46


M

500

32
160
110
143

.36
.32

.12

59


N

500

15
140
100
119

.35
.32

.09

71


O

300

13
130
100
99

.35
.31

.22

76


P

340

13
120
100
96

.35
.31

.07

82


Q

280

13
120
100
67

.35
.31

.06

86


S

500

21
120
110
49

.35
.31

.04

90


T

500

10
140
110
49

.34
.3

.03

95


U

520

4.1
140
74
41

.34
.28

.02

99


V

505

3.6
140
64
33

.34
.26

.02

102


X

440

3.2
140
63
26

.34
.25

.003

104


Y

500

9.7
140
71
25

.33
.23



107


Z

500

2.4
130
62
17

.33
.21



108









Example 5
Sodium Zeolite Absorption of Ammonia in a Five-Column Configuration, Including Migration of Zeolite
FIGS. 7A to 7H illustrate a five-column run on a natural supply of aqueous medium located in Colorado City, Colo. The initial concentration of target materials in the aqueous medium was approximately 97 mg/L calcium, 14 mg/L magnesium, 19 mg/L potassium, 16 mg/L sodium, 29 mg/L ammonia (note that these values fluctuate slightly due to the natural source feed). The run was performed at a flow rate of approximately 1.1 L/minute for a period of approximately 24.5 hours. As can be seen in FIG. 7, the concentration of ammonia in the column 5 effluent is at all times less than 1 mg/L, indicating that the five-column configuration a the above mentioned flow rate is effective in removing ammonia from an aqueous medium to levels less than the acceptable discharge levels set by the EPA.
The zeolite was counter-current migrated throughout the course of the experiment. Note that the zeolite in column one was regenerated after day three, i.e., passed through a brine solution, and re-connected to the system after column five. The concentration of the regenerated column one effluent is lower than the column five effluent, indicating that the regenerated column one is still effective at removing even low concentrations of ammonia.
The present Example illustrates the utility of the present invention for removing ammonia from an aqueous medium-especially with regard to using a counter-current migration of zeolite.
Example 6
Sodium Zeolite Absorption of Ammonia in a Five-Column Configuration Including Migration of Zeolite
Table 12 illustrates results from a five-column run on a natural supply of aqueous medium located in Burley, Id. The initial concentration of the aqueous medium was approximately 58 mg/L calcium, 14 mg/L magnesium, 25 mg/L potassium, 12.6 mg/L ammonia and 150 mg/L sodium. As in Example 5, the values tended to fluctuate due to the natural source of the feed. The flow rate for the run was approximately 1.7 L/minute over a period of 455 minutes.
The results show that the concentration of ammonia in the column 5 effluent (discharge) was at all times less than 1 mg/L ammonia, indicating that a five-column configuration at the above mentioned flow rate was effective at removing ammonia from this particular water source.







TABLE 12







Five Column Run at Burley Idaho, Feed














Elapsed
Cum.

Bed
Cum
Feed, mg/L


















Day
Time
Time
Minutes
Rate
Vol.
BV
Ca
Mg
K
NH3
Na





1
13:50
0
0
1700


58
14
25
12.6
150


1
15:00
70
70
1700
64
64
58
14
25
12.6
150



15:55
125
125
1700
51
115
58
14
25
12.6
150


2
 9:00
0
125
1700
0
115
59
14
25
14.9
145


2
10:00
60
185
1700
55
170
59
14
25
14.9
145



12:00
120
305
1700
110
280
61
14
25
14
135



14:00
120
425
1700
110
391
60
14
25
14
140



14:30
30
455
1700
28
418
60
14
25
14
140














Cum.

meq fed to circuit

















Day
Time
Elapsed Time
Minutes
Rate
Liters
Ca
Mg
K
NH3
Na





1
13:50
0
0
1700
0


1
15:00
70
70
1700
119
345
69
76
88
776



15:55
55
125
1700
93.5
271
54
60
69
610


2
 9:00
0
125
1700
0
0
0
0
0
0


2
10:00
60
185
1700
102
301
59
65
89
643



12:00
120
305
1700
204
622
118
130
168
1197



14:00
120
425
1700
204
612
118
130
168
1242



14:30
30
455
1700
51
153
29
33
42
310


1
13:50
0
0


1
15:00
70
70



15:55
55
125


2
 9:00
0
125


2
10:00
60
185



12:00
120
305



14:00
120
425



14:30
30
455


1
13:50
0
0


1
15:00
70
70



15:55
55
125


2
 9:00
0
125


2
10:00
60
185



12:00
120
305



14:00
120
425



14:30
30
455










Five Column Run at Burley Idaho - Col. 1 discharge, mg/L














Elapsed
Cum.

Bed
Cum
Column 1 Discharge, mg/L


















Day
Time
Time
Minutes
Rate
Vol.
BV
Ca
Mg
K
NH3
Na





1
13:50
0
0
1700


1
15:00
70
70
1700
64
64
12
12
2
1.33
240



15:55
125
125
1700
51
115
12
12
2
1.33
240


2
 9:00
0
125
1700
0
115


2
10:00
60
185
1700
55
170



12:00
120
305
1700
110
280



14:00
120
425
1700
110
391



14:30
30
455
1700
28
418














Cum.

meq discharging Column 1

















Day
Time
Elapsed Time
Minutes
Rate
Liters
Ca
Mg
K
NH3
Na





1
13:50
0
0
1700
0


1
15:00
70
70
1700
119
71
59
6.1
9.3
1242



15:55
55
125
1700
93.5
56
46
4.8
7.3
976


2
 9:00
0
125
1700
0


2
10:00
60
185
1700
102



12:00
120
305
1700
204



14:00
120
425
1700
204



14:30
30
455
1700
51


















Day
Time
Elapsed Time
Cum. Minutes
Ca
Mg
K
NH3
Na














1
13:50
0
0
Net Loading on Column 1















1
15:00
70
70
0
0
0
0
0



15:55
55
125
274
10
70
79
−466


2
 9:00
0
125
215
7.7
55
62
−366


2
10:00
60
185



12:00
120
305



14:00
120
425



14:30
30
455


1
13:50
0
0











1
15:00
70
70
Cumulative Loading on Column 1
















15:55
55
125
0
0
0
0
0


2
 9:00
0
125
274
10
70
79
−466


2
10:00
60
185
489
17
125
141
−832



12:00
120
305



14:00
120
425



14:30
30
455










Five Column Run at Burley Idaho - Col. 2 discharge, mg/L














Elapsed
Cum.

Bed
Cum
Column 2 Discharge, mg/L


















Day
Time
Time
Minutes
Rate
Vol.
BV
Ca
Mg
K
NH3
Na





1
13:50
0
0
1700


1
15:00
70
70
1700
64
64
<1
<2
2
0.8
290



15:55
125
125
1700
51
115
<1
<2
2
0.8
290


2
 9:00
0
125
1700
0
115


2
10:00
60
185
1700
55
170
19
18
3
2.3
215



12:00
120
305
1700
110
280
40
16
7
5.8
180



14:00
120
425
1700
110
391
50
14
11
9.1
165



14:30
30
455
1700
28
418
50
14
11
9.1
165














Cum.

meq discharging Column 2

















Day
Time
Elapsed Time
Minutes
Rate
Liters
Ca
Mg
K
NH3
Na





1
13:50
0
0
1700
0
6
9.8
6.1
5.6
1500


1
15:00
70
70
1700
119
4.7
7.7
4.8
4.4
1179



15:55
55
125
1700
93.5
0
0
0
0
0


2
 9:00
0
125
1700
0
97
76
7.8
14
953


2
10:00
60
185
1700
102
408
134
37
70
1597



12:00
120
305
1700
204
510
118
57
109
1463



14:00
120
425
1700
204
128
29
14
27
366



14:30
30
455
1700
51












Net Loading on Column 2















Day
Time
Elapsed Time
Cum. Minutes
Ca
Mg
K
NH3
Na





1
13:50
0
0
0
0
0
0
0


1
15:00
70
70
65
49
0
3.7
−259



15:55
55
125
51
38
0
2.9
−203


2
 9:00
0
125
0
0
0
0
0


2
10:00
60
185
204
−17
57
76
−310



12:00
120
305
214
−17
94
98
−399



14:00
120
425
102
0
73
59
−222



14:30
30
455
26
0
18
15
−55












Cumulative Loading on Column 2















Day
Time
Elapsed Time
Cum. Minutes
Ca
Mg
K
NH3
Na





1
13:50
0
0
0
0
0
0
0


1
15:00
70
70
65
49
0



15:55
55
125
117
87
0


2
 9:00
0
125
117
87
0


2
10:00
60
185
321
71
57



12:00
120
305
535
54
151



14:00
120
425
637
54
224



14:30
30
455
663
54
243










Five Column Run at Burley Idaho - Col. 3 discharge, mg/L














Elapsed
Cum.

Bed
Cum
Column 3 Discharge, mg/L


















Day
Time
Time
Minutes
Rate
Vol.
BV
Ca
Mg
K
NH3
Na





1
13:50
0
0
1700


1
15:00
70
70
1700
64
64
<1
<2
2
1.05
295



15:55
125
125
1700
51
115
<1
<2
2
1.05
295


2
 9:00
0
125
1700
0
115


2
10:00
60
185
1700
55
170
1
<2
1
1.2
280



12:00
120
305
1700
110
280
13
16
2
1.7
215



14:00
120
425
1700
110
391
33
16
3
2.9
190



14:30
30
455
1700
28
418
33
16
3
2.9
190














Cum.

meq discharging Column 3

















Day
Time
Elapsed Time
Minutes
Rate
Liters
Ca
Mg
K
NH3
Na





1
13:50
0
0
1700
0
6
9.8
6.1
7.4
1526


1
15:00
70
70
1700
119
4.7
7.7
4.8
5.8
1199



15:55
55
125
1700
93.5
0
0
0
0
0


2
 9:00
0
125
1700
0
5.1
8.4
2.6
7.2
1242


2
10:00
60
185
1700
102
133
134
10
20
1907



12:00
120
305
1700
204
337
134
16
35
1685



14:00
120
425
1700
204
84
34
3.9
8.7
421



14:30
30
455
1700
51












Net Loading on Column 3















Day
Time
Elapsed Time
Cum. Minutes
Ca
Mg
K
NH3
Na





1
13:50
0
0
0
0
0
0
0


1
15:00
70
70
0
0
0
−1.8
−26



15:55
55
125
0
0
0
−1.4
−20


2
 9:00
0
125
0
0
0
0
0


2
10:00
60
185
92
67
5.2
6.6
−288



12:00
120
305
275
0
26
49
−310



14:00
120
425
173
−17
42
74
−222



14:30
30
455
43
−4.2
10
19
−55












Cumulative Loading on Column 3















Day
Time
Elapsed Time
Cum. Minutes
Ca
Mg
K
NH3
Na





1
13:50
0
0
0
0
0
0
0


1
15:00
70
70
0
0
0
−1.8
−26



15:55
55
125
0
0
0
−3.1
−46


2
 9:00
0
125
0
0
0
−3.1
−46


2
10:00
60
185
92
67
5.2
3.5
−334



12:00
120
305
367
67
31
53
−645



14:00
120
425
541
50
73
127
−867



14:30
30
455
584
46
83
146
−922










Five Column Run at Burley Idaho - Col. 4 discharge, mg/L














Elapsed
Cum.

Bed
Cum
Column 4 Discharge, mg/L


















Day
Time
Time
Minutes
Rate
Vol.
BV
Ca
Mg
K
NH3
Na





1
13:50
0
0
1700


1
15:00
70
70
1700
64
64
<1
<2
2
1.01
295



15:55
125
125
1700
51
115
<1
<2
2
1.01
295


2
 9:00
0
125
1700
0
115


2
10:00
60
185
1700
55
170
<1
<2
1
1.1
290



12:00
120
305
1700
110
280
2
16
1
1
235



14:00
120
425
1700
110
391
10
18
1
1.3
220



14:30
30
455
1700
28
418
10
18
1
1.3
220














Cum.

meq discharging Column 4

















Day
Time
Elapsed Time
Minutes
Rate
Liters
Ca
Mg
K
NH3
Na





1
13:50
0
0
1700
0
6
9.8
6.1
7.1
1526


1
15:00
70
70
1700
119
4.7
7.7
4.8
5.6
1199



15:55
55
125
1700
93.5
0
0
0
0
0


2
 9:00
0
125
1700
0
5.1
8.4
2.6
6.6
1286


2
10:00
60
185
1700
102
20
134
5.2
12
2084



12:00
120
305
1700
204
102
151
5.2
16
1951



14:00
120
425
1700
204
26
38
1.3
3.9
488



14:30
30
455
1700
51


















Day
Time
Elapsed Time
Cum. Minutes
Ca
Mg
K
NH3
Na














1
13:50
0
0
Net Loading on Column 4















1
15:00
70
70
0
0
0
0
0



15:55
55
125
0
0
0
0.3
0


2
 9:00
0
125
0
0
0
0.2
0


2
10:00
60
185
0
0
0
0
−44



12:00
120
305
0
0
0
0.6
−177



14:00
120
425
112
0
5.2
8.4
−266



14:30
30
455
235
−17
10
19
−67












Cumulative Loading on Column 4















Day
Time
Elapsed Time
Cum. Minutes
Ca
Mg
K
NH3
Na





1
13:50
0
0
0
0
0
0
0


1
15:00
70
70
0
0
0
0.3
0



15:55
55
125
0
0
0
0.5
0


2
 9:00
0
125
0
0
0
0.5
0


2
10:00
60
185
0
0
0
1.1
−44



12:00
120
305
112
0
5.2
9.5
−222



14:00
120
425
347
−17
16
29
−488



14:30
30
455
405
−21
18
34
−554










Five Column Run at Burley Idaho - Col. 5 discharge, mg/L














Elapsed
Cum.

Bed
Cum
Column 4 Discharge, mg/L


















Day
Time
Time
Minutes
Rate
Vol.
BV
Ca
Mg
K
NH3
Na





1
13:50
0
0
1700


1
15:00
70
70
1700
64
64



15:55
125
125
1700
51
115


2
 9:00
0
125
1700
0
115


2
10:00
60
185
1700
155
170
2
<2
1
0.2
335



12:00
120
305
1700
1110
280
1
<2
1
0.4
285



14:00
120
425
1700
1110
391
3
18
1
0.1
225



14:30
30
455
1700
128
418
3
18
1
0.1
225














Cum.

meq discharging Column 5

















Day
Time
Elapsed Time
Minutes
Rate
Liters
Ca
Mg
K
NH3
Na





1
13:50
0
0
1700
0


1
15:00
70
70
1700
119
0
0
0
0
0



15:55
55
125
1700
93.5
0
0
0
0
0


2
 9:00
0
125
1700
0
0
0
0
0
0


2
10:00
60
185
1700
102
10
8.4
2.6
1.2
1486



12:00
120
305
1700
204
10
17
5.2
4.8
2528



14:00
120
425
1700
204
31
151
5.2
1.2
1996



14:30
30
455
1700
51
7.7
38
1.3
0.3
499












Net Loading on Column 5















Day
Time
Elapsed Time
Cum. Minutes
Ca
Mg
K
NH3
Na





1
13:50
0
0


1
15:00
70
70



15:55
55
125


2
 9:00
0
125


2
10:00
60
185
−5.1
0
0
5.4
−200



12:00
120
305
101
18
0
7.2
−443



14:00
120
425
71
0
0
14
−44



14:30
30
455
18
0
0
3.6
−11












Cumulative Loading on Column 5















Day
Time
Elapsed Time
Cum. Minutes
Ca
Mg
K
NH3
Na





1
13:50
0
0


1
15:00
70
70



15:55
55
125


2
 9:00
0
125
0
0
0
0
0


2
10:00
60
185
−5.1
0
0
5.4
−200



12:00
120
305
5.1
118
0
13
−643



14:00
120
425
77
118
0
27
−687



14:30
30
455
94
118
0
31
−698









Example 7
Calcium Zeolite Absorption of Ammonia from an Aqueous Medium Containing Calcium, Magnesium, and Potassium
FIGS. 8A–F provide tabular and graphical results of a five-column test run on a feed solution containing approximately 3.5 mg/L calcium, 2 mg/L magnesium, 30 mg/L potassium, 36 mg/L ammonia and 13 mg/L sodium. The run was performed at a flow rate of 0.95 L/minute for a time period of 280 minutes. FIG. 8 shows that the concentration of ammonia in column 5 effluent began at 0.03 mg/L and finished at 2.2 mg/L. The data indicates that the five-column configuration at the above-mentioned flow rate is effective to remove ammonia to a discharge level of less than 1 mg/L. FIGS. 8A–8F illustrate the MEQ per gram loading of the various components of the feed on each column versus bed volume. Again, this graphical data shows that the calcium on the zeolite is replaced by ammonia during the absorption process.
FIGS. 9A–9F, represent the results of a continuation of the run shown above in this Example (FIGS. 8A–F) in which column one was eluted with a calcium chloride brine solution and placed back into the test after column five. The data indicates that the concentration of ammonia in the regenerated column one effluent is at all times, but for the final reading, at a concentration of less than 1 mg/L. The final concentration of ammonia in the column one effluent was 1.5 mg/L, suggesting that the absorption of ammonia can be accomplished in a batch or a continuous process.
Finally, FIGS. 10A–F represents tabular and graphical results of a continuation of the above data in which the second column was regenerated and migrated and the concentration of potassium in the feed solution was increased from approximately 30 mg/L initially to approximately 90 mg/L. These results show that the transfer of potassium through zeolite to the brine does not substantially effect the absorption of ammonia.
Example 8
Industrial Scale-Up for Ammonia Removal and Destruction at a Theoretical Treatment Facility
The following Table 13 provides a potential scale-up calculation for removing and destroying ammonia from a hypothetical one million gallon a day treatment facility. The amount of zeolite material and the size of the tank(s) for commercial applications are selected based on a number of design parameters, including but not limited to, average amount of ammonia in the water, desired levels of reduction, plant capacity (1 MGD) and the types of zeolites used.
Predictable scale-up for the methods according to the present invention are shown below with respect to a theoretical one million gallon per day treatment facility.
Table 13 summarizes a typical scale-up calculation for design of an industrial capacity system (1 MGD). A 98% reduction in ammonia concentration at the facility is attainable by using approximately 125 tons of zeolite. Each absorption column should be approximately 9 feet in diameter and 25 feet tall. A maximum rate of migration of the zeolite is approximately 116 pounds per minute and a minimum rate is 58 pounds per minute. Ultimately, the system provides for the destruction of approximately 1,673 pounds of ammonium sulfate solution per day.







TABLE 13







Material Balance For Calcium, Sulphuric acid and Ammonia At a 1


MGD Facility









Value














Input Data




Gallons per day
1.008 million



Gallons per minute
700



Ammonia in feed (mg/L)
40



Assumptions



# lime/# NH3 for stripping
1.64



zeolite



# lime/# NH3 for stripping
0.82



brine



# lime/# NH3 for
1.55



destruction



# H2SO4/#  NH3 for ammonia
2.875



removal



CaSO4 produced/# of NH3
5.1



Results



1000 gallons/day
1,008



Pounds per day ammonia
334.7



Pounds zeolite loaded/day
83,664



Pounds zeolite stripped/min
58



Tons Zeolite in plant/3 days
125



# H2SO4 to remove
962



ammonia/day



# (NH4)SO4/day
1,297



# lime for stripping zeolite
549



# lime for stripping brine
274



# lime for destruction
519



# total lime/day
1,342



Absorption



Flow rate gpm/ft3
10



Square feet needed
70



Diameter of tank
9.44



Height of tank
25



Depth of zeolite/tank
13



Cubic feet zeolite/tank
875



Pounds zeolite/tank
48,125



Tons zeolite/tank
24



Number of loading tank
4



Tons zeolite in absorption
96.25



circuit



Zeolite maximum
116 pounds/min



advancement rate



Zeolite minimum
58 pounds/min



advancement rate



Desorption



Retainage time (minimum)
2 hours



Cubic feet advancement of
2.1



zeolite/min



Pounds capacity
13,944



Tons capacity
7



Cubic feet zeolite capacity
254



Depth of zeolite
15



Square feet of base
16.9



Diameter of base
4.6



Brine flow rate/ft3
6



Gallons per minute brine
101.4



Cubic feet of brine/minute
13.6



Minimum bed volumes
770



Ammonia Stripping



Flow rate to ammonia
101.4



stripper



Square feet of stripper
101.4



Diameter of stripper
11.4



Height of stripper
20



Air flow of stripper
40,673 ft3



Lime to stripper
0.93 lb/minute



Ammonia Recovery



Diameter of absorber
11.4



Flow rate of absorber
507



Air flow to absorber
40,673 ft3



H2SO4 to absorber
0.67 lb/minute



Pounds (NH4)2SO4
0.90 lb/minute



produced/minute



Zeolite Rinse



Retainage time (minimum)
0.5 hours



Cubic feet advancement of
2.1



zeolite/minute



Pounds capacity
3,486



Tons capacity
1.7



Cubic feet zeolite capacity
63



Depth of zeolite
15



Square feet of base
4.2



Diameter of base
2.3



Brine flow rate/ft3
6



Gallons per minute rinse
25.4



solution



Cubic feet of brine/minute
3.4



Minimum bed volumes
48



Ammonia Destruction



Bleed stream to destruction
1,673.28 lbs/day



stripper



Cubic feet liquid to
26.82 ft3/day



destruction stripper



Liquid to stripper/minute
0.139 gallons/minute



Air to destruction
55.865 ft3/min



stripper/minute



Gypsum production
1706.7456/day



Number/minute gypsum
1.19



production










The above discussed scale-up calculation illustrates the utility of the present invention, for large scale application of the present invention.
Example 9
Pilot Plant Study—Ammonia Removal Pilot Plant at Tomahawk Wastewater Treatment Facility, Johnson County, Kansas.
The Tomahawk wastewater treatment facility has a trickling filter system with ammonia discharges that limit the plant throughput. The plant has a current capacity of 9 MGD, but operates at 4 MGD and has an ammonia permit of 4 mg/L.
A six day pilot study was conducted to verify the applicability of the methods and apparatuses of the present invention at removing ammonia from a wastewater source. The pilot study was set-up to test 3.5 gallons/minute, having a feed concentration of 11.65 mg/L ammonia. A total of 29,000 gallons of water was treated during the study. Sampling and analysis were conducted on-site using a Hanna Ion Specific Meter for ammonia and analysis was re-checked at the Johnson County Wastewater Lab (note that discrepancies between lab results appear to be due to the differences in the sample analysis temperature).
As shown in Table 14, the pilot ammonia removal plant was effective at removing a sub-permit level of ammonia. Ultimately, ammonia discharge was lowered to 1.14 mg/L, showing an ammonia recovery of 90.2%. The chemical consumption used during the test was below expectation.







TABLE 14







Johnson County Pilot Plant
















JCW Lab
WRT




JCW Lab
WRT feed
discharge
discharge




feed NH3—N
NH3—N
NH3—N
NH3—N


Day
Time
mg/L
mg/L
mg/L
mg/L















1
12 PM 
10.52
12.80
0.17
0.95


1
2 PM
12.20
15.40
0.10
1.12


1
3 PM
10.06
10.60
0.56
1.14


4
7 PM
11.24
9.12
0.29
0.70


5
8 AM
8.84
8.78
0.98
1.43



Average:
10.57
11.34
0.39
1.07









The data in the pilot study shows the utility of the present invention at removing ammonia from a waste water stream.
Example 10
Pilot Plant Study-Ammonia Removal Pilot Plant at Colorado City Wastewater Treatment Facility, Colo. City, Colo.
The Colorado City wastewater treatment facility has an aerated lagoon system with ammonia discharges that limit the plant throughput. The plant has a current capacity of about 0.35 MGD and an ammonia permit level of 10 mg/L, which is expected to be decreased to 2 mg/L in the near future.
A six day pilot study was conducted to verify the applicability of the methods and apparatuses of the present invention at removing ammonia from a wastewater source. The pilot study was set-up to test 15 gallons/minute, having a feed concentration of 16.2 mg/L ammonia. A total of 65,300 gallons of water was treated during the study. Sampling and analysis were conducted on-site using a Hanna Ion Specific Meter for ammonia.
As shown in FIG. 11, the pilot ammonia removal plant was effective at removing a sub-permit level of ammonia. Ultimately, ammonia discharge was lowered to 0.6 mg/L, showing an ammonia recovery of 96.5%. The chemical consumption used during the test was at or below expectation.
Example 11
Pilot Plant Study-Air Stripping Ammonia from Feed Having High Ammonia Levels
The pilot study was performed for the City of Harrisburg in an effort to remove ammonia directly to an air stripping unit from a high ammonia waste stream (the secondary digester discharge). The basic process consist of first clarifying the feed medium from the secondary digester and filter press returning solids to the filter press for removal from the system and air stripping the ammonia from the medium. The ammonia is then recaptured in a mild acid solution to form up to 20% ammonium sulfate. The low ammonia feed medium is then returned to the process plant. The ammonium sulfate can be used as fertilizer or burned to release nitrogen as has been discussed above.
Note that it was originally hoped that the secondary digester discharge could be handled with no additional clarification but the discharge was too viscous, having to many large particles of plastic and other waste. As such, it was necessary to clarify the solution prior to air stripping.
The schematic diagram in FIG. 12 provides an overview of the steps performed in the process. For example, feed 500 is filtered 502 and/or clarified 504 to provide a high ammonia stream 506 for the air stripping process. The filtrate cycles through an ammonia stripper 508 and scrubber 510 as previously described, to provide an ammonium sulfate solution for storage in a tank 512. Acid 514 and caustic 516 storage tanks are shown. The data, as illustrated in Table 15, shows that ammonia recoveries of about 90 to 98% could be achieved when the pH was maintained at about 10. Caustic consumption was lower than expected, averaging 3.68 pounds per 1000 gallons treated. Recovery is directly related to the pH of the solution, where a pH of 10 to 12 is necessary to have recovery over 90%. The average results of the four day test were: feed rate=0.52 gallons/min., feed concentration=274 mg/L ammonia, discharge pH=10, the discharge ammonia concentration=21 mg/L, providing a recovery of 93% on average.







TABLE 15





Ammonia Recover From A Highly Concentrated Ammonia Source























Feed
Feed
Feed
Feed pH



Day
Time
Temp
Flow
Total
Target/Actual
Feed NH4





1
start

0.53
216.7
10.5/10.2
181



20 min

0.57
224
10.5/11
212



42


235.8



56

0.51
243.1
10.5/10.2
196



80

0.54
256.5
10.5/10.2



110

0.45
271.9
10.2/10.8
193/217



140

0.48
287.2
10/11
192



170

0.51
301.4
10/10
188



200
27.4° C.
0.56
316.4
10/10.1
99



230

0.47
330.5
10.0/9.7
180.5



290

0.53
356
9/9.3
609



320

0.55
377.7
9/8.7



350
27.5° C.
0.61
391.3
9/8.9
210



380

0.61
410.2
9/9.8



410

0.53
426.2
9.8/10
209.5



440
27.6° C.
0.5
442.5
9.5/10.6



455




288.5



470

0.51
458.3
9.5/9.8



500

0.5
473.2
9.2/9.8



530

0.49
484.2
9.2/10.9


2
start



20

0.50
503.1
9.4



50

0.51
517.4
9.1
236



80
26.0° C.
0.50
531.8
9.9



110

0.48
546.6
9.7
213



140

0.49
561.5
10



170

0.54
577.4
9.7
212



200

0.55
592.3
9.5
211



230

0.54
607.2
9.9
214


3
start


619.2



15
30.2° C.
0.52
627.5
9.9
283



45

0.52
643.4
10.2
270



75

0.52
658.5
10.3
278



105

0.55
674.6
11
251



135

0.53
689.8
10.7
266



165

0.43
702.6
9.9
295


3
re-start

0.48
713
9.5



36
28.8° C.
0.50
821.9
11.2
301



66

0.53
840.3
10
395



90

0.55
852.4
10.3
353



120

0.53
868.4
11.1



150

0.54
884.2
10.4
311


4
start




10
25.3° C.
0.5
892.2
9.9



40

0.52
905.9
10.2
573



70

0.49
921.2
10.1
391



100

0.57
937.6
10.8
307



130

0.52
954.4
10.4
307



160

0.53/





0.51
968.5
10.2
293



190

0.51
984.8
10.2
300



220

0.49
999.6
10.3
301



250

0.50
1014.9
10.9
299



280

0.47
1029
10.4
295



310

0.5
1043.7
10.7
316



330



340

0.5
1058.6
10.4
316



370

0.5
1073.6
10.9
298




















Dis-
Dis-







Caustic
charge
charge
Concen.
Conc.
Conc.


Day
Time
added
pH
NH4
flow
pH
NH4





1
start

10.3
7.82
1.24

0.167%



20 min

10.5
15.58
1.26

0.189



42
75/75
10.6



56
120/195
10.4
6.6
1.27
1.6
0.217



80
195/390
10.9

1.27
1.7



110
185/575
10.9
3.06
1.28
1.8
0.255



140
205/780
10.1
3.55
1.27
1.9



170
155/935
10.1
8.20
1.27
2
0.323



200
175/1110
10.2
13.8
1.27
2.2



230
160/1270
10.6
3.86
1.28
2.5



290
245/1515
9.7
43.54
1.28
3.3
0.42



320
165/1680
9.2

1.29
3.1



350
125/1805
9.7
35.94
1.28
3.6
0.477



380
135/1940
9.3

1.28
3.4



410
145/2085
9.4
35.68
1.28
3.3
0.519



440
160/2245
9.8

1.28
4.2



455

9.5
29.2



470
170/2415
10.1

1.28
3.4



500
135/2550
10.0

1.28
3.7



530
125/2675
9.8

1.28
3.2


2
start



20
60/60
9.5

1.16
3.1



50
125/185
9.9
10.7
1.21
5.0
1962



80
135/320
10

1.20
3.5



110
135/455
9.9
5.08
1.20
3.8
6794



140
125/580
10

1.20
5.0



170
270/850
9.7
92
1.21
3.0
7534



200
210/1060
9.4
24
1.21
4.2



230
240/1300
9.9
25

3.2


3
start



15
150/150
9.4
53.8
1.26
3.2



45
230/380
9.8
29.1
1.27
3.4



75
270/650
9.9
26.3
1.28
3.5



105
230/880
10
28.8
1.30
3.5



135
300/1180
10.3
15.3
1.28
4.6



165
295/1475
10.5
22.9
1.27
4


3
re-start
200/1675
10.1

1.24
3.8



36
570/2245
10.2
16.7
1.24
3.9



66
330/2575
10
15.5
1.25
3.5



90
230/2805
10.2
16.1
1.25
3.7



120
270/3075
10.1

1.26
3.6



150
360/3435
10
21
1.27
3.7


4
start



10
80/80
9.9

1.21
2.6



40
260/340
10.2
25.3
1.22
3.9



70
360/700
10.2
20.1
1.23
3.5



100
300/1000
10.2
26.8
1.23
3.6



130
340/1340
10.3
18.9
1.23
4.2



160
310/1650
10.3
18.3
1.23
3.9



190
360/2010
10.3
15.3
1.24
3.9



220
270/2280
10.2
11.8
1.22
3.8



250
350/2630
10.3
11.5
1.24
3.8



280
265/2895
10.3
8.8
1.23
3.8



310
295/3190
10.3
11.7
1.23
4.1



330




340
370/3560
10.3
12.6
1.23
3.5



370
320/3880
10.3
11.2
1.23
4.3

















Acid

NaOH



Day
Time
Added
Air Flow
ml
H2SO4





1
start

0.15/1528



20 min

0.145/1502



42

0.15/1528



56

0.14/1476



80

0.145/1502



110

0.135/1450



140

0.135/1450



170
50/50
0.14/1476



200

0.12/1371



230

0.14/1476



290

0.13/1424



320
90/140
0.12/1371
835
410



350
85/225
0.11/1319
710
325



380
98/323
0.12/1371
575
227



410
97/420
0.12/1371
430/1000
130/500



440
100/520
0.13/1424
840
400



455



470
105/625
0.12/1371
670
295



500
70/695
0.125/1397
535
225



530
115/810
0.11
410
110


2
start



20

0.155/1555
940
485



50

0.135/1450
815
445



80
185
0.135/1450
680
315



110
90/275
0.135/1450
545
225



140
95/365
0.135/1450
420
405



170
75/440
0.135/1450
150
330



200
75/515
0.135/1450
790
255



230
125/640

550
130


3
start



15
15/15
0.26/1420
850
485



45
130/145
0.16/1581
620
355



75
130/275
0.16/1581
350
225



105
110/385
0.155/1555
770
390



135
140/525
0.16/1581
470
250



165
285/690
0.155/1555
175
 85


3
re-start
80/770 

800
420



36
210/980
0.07/1060
230
210



66
160/1140
0.26
660
340



90
100/1240
0.16/1581
430
240



120
110/1350
0.16/1581
730
390



150
170/1520
0.16/1581
370
220


4
start



10
5/5
0.17/1634
920
495



40
5/10
0.16/1581
660
490



70
165/175
0.16/1581
300
325



100
155/330
0.155/1555
700
170



130
155/485
0.15
360
345



160
120/605
0.15
690
225/500



190
120/725
0.15/1555
330
345



220
125/850
0.15/1555
730
220



250
150/1000
0.15/1555
380
370



280
130/1130
0.15
735
240/500



310
95/1225
0.145/1502
440
405



330


180/1000



340
145/1370
0.14/1502
890
260



370
165/1535
0.14
570
95









The data in this Example shows that ammonia can be recovered directly from a secondary or high ammonia source. Caustic consumption for pH control was less than anticipated.
It should be understood for purposes of this disclosure, that various changes and modifications may be made to the invention that are well within the scope of the invention. Numerous other changes may be made which will readily suggest themselves to those skilled in the art and which are encompassed in the spirit of the invention disclosed herein and as defined in the appended claims.

## Claims

1. A system for removing ammonia from an aqueous medium comprising:
an ammonia absorption unit for contacting an amount of zeolite with the aqueous medium;
an ammonia elution unit for eluting the ammonia from the zeolite with a brine solution;
an air stripping unit for dissociating the ammonia from the brine solution and providing an ammonia gas;
an acid wash unit for treating the ammonia gas with an acid wash and forming an ammonium salt;
a second air stripping unit for receiving the ammonium salt and a base to dissociate the ammonia in the form of ammonium hydroxide and providing an ammonia gas; and
a combustion unit for receiving the ammonium gas to be burned at a controlled temperature.

2. The system of claim 1 further comprising:
a pre-burner unit for providing an exhaust gas to the ammonia gas in the combustion unit, wherein the exhaust gas raises the temperature within the combustion unit to a level appropriate for the combustion of the ammonia gas.

3. The system of claim 1 further comprising:
a re-circulation unit for concentrating the ammonium salt, the re-circulation unit providing the ammonium salt solution back to the air stripping unit for additional ammonium salt production.

4. The system of claim 1 further comprising:
a zeolite regeneration unit for regenerating fresh-zeolite from spent zeolite and providing the regenerated zeolite for continued use in the absorption unit.