Note: Descriptions are shown in the official language in which they were submitted.
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SYSTEM AND METHOD FOR MANIPULATION OF ION CONCENTRATION TO MAXIMIZE
EFFICIENCY OF ION EXCHANGE
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The following disclosure relates to US Provisional Application
62/286,927, filed January 25,
2016 entitled SYSTEM AND METHOD FOR MANIPULATION OF ION CONCENTRATION TO
MAXIMIZE EFFICIENCY OF ION EXCHANGE MATERIALS, which is herein incorporated by
reference in its entirety, and to which the present application also claims
priority; co-pending application
MOBILE PROCESSING SYSTEM FOR HAZARDOUS AND RADIOACTIVE ISOTOPE REMOVAL,
Ser. No. 14/748,535 filed June 24, 2015 with a priority date of June, 24,
2014, which is herein
incorporated by reference in its entirety; co-pending patent application
HELICAL SCREW ION
EXCHANGE AND DESICCATION UNIT FOR NUCLEAR WATER TREATMENT SYSTEMS, Ser.
No. 15/136,600 filed April 22, 2016 with a priority date of April 24, 2015,
which is herein incorporated
by reference in its entirety: co-pending patent application ISM MEDIA REMOVAL
FROM VESSEL
FOR VITRIFICATION, Ser. No. 15/012,101 filed on February 1, 2016 with a
priority date of February 1,
2015, which is herein incorporated by reference in its entirety; and co-
pending application ADVANCED
TRITIUM SYSTEM AND ADVANCED PERMEATION SYSTEM FOR SEPARATION OF TRITIUM
FROM RADIOACTIVE WASTES, Ser. No. 15/171,183 filed on June 2, 2016 with a
priority date of
October 9, 2015, which is herein incorporated by reference in its entirety.
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TECHNICAL FIELD OF THE INVENTION
[0002] This disclosure relates generally to the manipulation of ion
concentration to dynamically manage
performance of ion exchange systems and processes.
BACKGROUND
[0003] Most existing mobile water processing systems are comprised of merely
one specific process, or
multiple processes within a single transportable module. Sites requiring waste
water remediation are
diverse in their specific requirements, topography, and the location. Natural
disaster, terrorist attacks, and
malfunctions often require rapid deployment of aid to mitigate overall damage
to the environment and
adverse effect to people living in the region surrounding the site. Current
water remediation systems are
not sufficient to perform this task. What is needed is a highly mobile, easily
transportable, scalable,
modular, easily deployable (often within 24 hours depending on site location,
topography, and
remediation requirements) and cost-effective system that can also be utilized
to manipulate ion
conentration and maximize ion exchange efficiency. The system may be highly
adaptable to differing
remediation requirements, scalable to maximize efficiency, and modular to
perform all remediation needs
including outputting water within safety standards as well as processing the
removed contaminants to
final disposition standards.
[0004] So as to reduce the complexity and length of the Detailed
Specification, and to fully establish the
state of the art in certain areas of technology, Applicant(s) herein expressly
incorporate(s) by reference all
of the following publications identified below. Applicant(s) expressly
reserve(s) the right to swear behind
any of the incorporated materials.
[0005] US Provisional Application 62/286,927, filed January 25, 2016 entitled
SYSTEM AND
METHOD FOR MANIPULATION OF ION CONCENTRATION TO MAXIMIZE EFFICIENCY OF
ION EXCHANGE MATERIALS, which is herein incorporated by reference in its
entirety, and to which
the present application also claims priority.
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[0006] Mobile Processing System for Hazardous and Radioactive Isotope Removal,
Ser. No. 14/748,535
filed June 24, 2015, with a priority date of June 24, 2014, which is herein
incorporated by reference in its
entirety.
[0007] Helical Screw Ion Exchange and Desiccation Unit for Nuclear Water
Treatment Systems, Ser.
No. 15/136,600 filed on April 22, 2016 with a priority date of April 24, 2015,
which is herein
incorporated by reference in its entirety.
[0008] ISM Media Removal from Vessel for Vitrification, Ser. No. 15/012,101
filed on February 1, 2016
with a priority date of February 1, 2015, which is herein incorporated by
reference in its entirety.
[0009] Advanced Tritium System and Advanced Permeation System for Separation
of Tritium from
Radioactive Wastes, Ser. No. 15/171,183 filed on June 2, 2016 with a priority
date of October 9, 2015,
which is herein incorporated by reference in its entirety.
[0010] Applicant(s) believe(s) that the material incorporated above is "non-
essential" in accordance with
37 CFR 1.57, because it is referred to for purposes of indicating the
background of the invention or
illustrating the state of the art. However, if the Examiner believes that any
of the above-incorporated
material constitutes "essential material" within the meaning of 37 CFR
1.57(c)(1)-(3), applicant(s) will
amend the specification to expressly recite the essential material that is
incorporated by reference as
allowed by the applicable rules.
[0011] Aspects and applications presented here are described below in the
drawings and detailed
description. Unless specifically noted, it is intended that the words and
phrases in the specification and the
claims be given their plain, ordinary, and accustomed meaning to those of
ordinary skill in the applicable
arts. The inventors are fully aware that they can be their own lexicographers
if desired. The inventors
expressly elect, as their own lexicographers, to use only the plain and
ordinary meaning of terms in the
specification and claims unless they clearly state othenvise and then further,
expressly set forth the
"special" definition of that term and explain how it differs from the plain
and ordinary meaning. Absent
such clear statements of intent to apply a "special" definition, it is the
inventors' intent and desire that the
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simple, plain and ordinary meaning to the terms be applied to the
interpretation of the specification and
claims.
[0012] The inventors are also aware of the normal precepts of English grammar.
Thus, if a noun, term, or
phrase is intended to be further characterized, specified, or narrowed in some
way, then such noun, term,
or phrase will expressly include additional adjectives, descriptive terms, or
other modifiers in accordance
with the normal precepts of English grammar. Absent the use of such
adjectives, descriptive terms, or
modifiers, it is the intent that such nouns, terms, or phrases be given their
plain, and ordinary English
meaning to those skilled in the applicable arts as set forth above.
[0013] Further, the inventors are fully informed of the standards and
application of the special provisions
of 35 U.S.C. 112, 1 6. Thus, the use of the words "function," "means" or
"step" in the Detailed
Description or Description of the Drawings or claims is not intended to
somehow indicate a desire to
invoke the special provisions of 35 U.S.C. 112, 1 6, to define the systems,
methods, processes, and/or
apparatuses disclosed herein. To the contrary, if the provisions of 35 U.S.C.
112, 1 6 are sought to be
invoked to define the embodiments, the claims will specifically and expressly
state the exact phrases
"means for" or "step for, and will also recite the word "function" (i.e., will
state "means for performing
the function of..."), without also reciting in such phrases any structure,
material or act in support of the
function. Thus, even when the claims recite a "means for performing the
function of. . ." or "step for
performing the function of. . .", if the claims also recite any structure,
material or acts in support of that
means or step, or that perform the recited function, then it is the clear
intention of the inventors not to
invoke the provisions of 35 U.S.C. 112, 1 6. Moreover, even if the
provisions of 35 U.S.C. 112, 1 6
are invoked to define the claimed embodiments, it is intended that the
embodiments not be limited only to
the specific structure, material or acts that are described in the preferred
embodiments, but in addition,
include any and all structures, materials or acts that perform the claimed
function as described in
alternative embodiments or forms, or that are well known present or later-
developed, equivalent
structures, material or acts for performing the claimed function.
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BRIEF DESCRIPTION OF THE FIGURES
[0014] A more complete understanding of the systems, methods, processes,
and/or apparatuses disclosed
herein may be derived by referring to the detailed description when considered
in connection with the
following illustrative figures. In the figures, like-reference numbers refer
to like-elements or acts
throughout the figures.
[0015] Figure 1 depicts a typical breakthrough curve.
[0016] Figure 2 is a graph depicting the relationship between the
concentrations of influent ions to the
capacity of the media without a concentration step.
[0017] Figure 3A depicts the concentration of influent ions and the capacity
of the media with and
without a concentration step when all ions in the liquid are concentrated
equally.
[0018] Figure 3B is a graph showing a comparison between the concentrations of
influent ions to the
capacity of the media with and without a concentration step wherein the
concentration step results in
higher concentration of one ion with respect to the other ions in the liquid.
[0019] Figure 3C is the graph of Figure 3B wherein the concentration step also
increases the capacity of
the media.
[0020] Figure 4 depicts the movement of the curve to achieve maximum capacity
as the concentration
step increases the ion to the ion exchange (IX) media.
[0021] Figure 5 depicts an exemplary nanofilter.
[0022] Figure 6 is an isometric view of an example embodiment Mobile
Processing System (MPS)
comprising five separate skids.
[0023] Figure 7 is a top view of the example embodiment of Figure 6.
[0024] Figure 8 depicts an example configuration of MPS skids.
[0025] Figure 9 depicts the NIPS configuration of Figure 8 with the addition
of a Nanofiltration skid.
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[0026] Figure 10 depicts the MPS configuration of Figure 9 with the addition
of an ISM skid for
processing of the permeate stream.
[0027] Figure 11 depicts two possible storage configurations comprising of a
Permeate Collection Tank
and a Concentrate Collection Tank.
[0028] Figure 12A depicts an embodiment of a nanofiltration step.
[0029] Figure 12B depicts the embodiment of Figure 12A with example flow rates
and tank volumes.
[0030] Figure 13 depicts an embodiment that includes a precipitation process.
[0031] Figure 14 depicts an embodiment that includes a metal hydroxide
precipitation process.
[0032] Elements and acts in the figures are illustrated for simplicity and
have not necessarily been
rendered according to any particular sequence or embodiment.
DESCRIPTION
[0033] In the following description, and for the purposes of explanation,
numerous specific details,
process durations, and/or specific formula values are set forth in order to
provide a thorough
understanding of the various aspects of exemplary embodiments. It will be
understood, however, by those
skilled in the relevant arts, that the apparatus, systems, and methods herein
may be practiced without
these specific details, process durations, and/or specific formula values. It
is to be understood that other
embodiments may be utilized and structural and functional changes may be made
without departing from
the scope of the apparatus, systems, and methods herein. In other instances,
known structures and devices
are shown or discussed more generally in order to avoid obscuring the
exemplary embodiments. In many
cases, a description of the operation is sufficient to enable one to implement
the various forms,
particularly when the operation is to be implemented in software. It should be
noted that there are many
different and alternative configurations, devices, and technologies to which
the disclosed embodiments
may be applied. The full scope of the embodiments is not limited to the
examples that are described
below.
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[0034] In the following examples of the illustrated embodiments, references
are made to the
accompanying drawings which form a part hereof, and in which is shown by way
of illustration various
embodiments in which the systems, methods, processes, and/or apparatuses
disclosed herein may be
practiced. It is to be understood that other embodiments may be utilized and
structural and functional
changes may be made without departing from the scope.
Ion Exchange and Ion Concentration Overview
[0035] Ion exchange (IX) materials operate on the conditions of equilibrium
between ions in solution and
ions in the media, such that if a particular ion in the solution is not in the
media, there is a dynamic where
a percentage of the ion will enter into the material creating equilibrium.
[0036] Ion exchange materials have varying capacities for ions, meaning that
there is limited space for a
given ion in the material. This varying capacity in operation can be termed
the "effective capacity" and
should approach the theoretical capacity of the material. All IX media contain
counter ions, such as (H+)
or (OH) that are exchanged when the material comes in contact with other ions
(such as Na, Ca2+, cr,
etc.). The extent of the exchange is a function of the material itself, the
physical conditions of the
solution, and the concentration of ions in the solution. The equilibrium
between an IX media and any
given ion, X. is dependent on the concentration of that ion (X) in solution
and other ions that may compete
with it for IX sites. When there is a low concentration ofX in solution, the
equilibrium forces are weak,
and the capacity of the media will be lower than the maximum theoretical
capacity. When there are other
ions in solution, mass action can help drive ion X into the media, or other
ions (Y, Z, etc.) may compete
with ion X for sites.
[0037] in using concentration technologies such as nanofiltration, reverse
osmosis, and evaporation the
total concentration of the ion X will increase. This increases the driving
force for X to be sorbed by the IX
material allowing the "effective capacity" of the media to more closely
approach the theoretical capacity.
In some embodiments, the addition of a concentration step prior to ion
exchange increases the rate of
reaction in the ion exchange media thus increasing the operating efficiency of
the media by reducing
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processing time. For the nanofilter option, chemicals can be added such that
the nanofilter selectively
concentrates one ion (or group of ions) over another ion (or group of ions).
For example, it can increase
the strontium concentration by four times in the concentrate stream while the
sodium concentration
remains the same, in some embodiments. The ratio of ion X to ion Y may be
increased, such that the
driving force to reach equilibrium is increased by reducing the relative
competition from Y. For a reverse
osmosis system, concentration can be controlled using other methods, but in
general, the concentrations
of all ions may be increased at the same factor. This results not in a better
ratio of Xto Y, but an overall
ionic driving force in the equilibrium system by mass action. Evaporation
methods work in a similar
manner as reverse osmosis systems.
[0038] This concept can be applied in any treatment of solutions containing
ions, and in which a sorption
material (IX, adsorption, or absorption material) is used. The adsorption or
absorption materials may
work in a similar manner, however in a different mechanism. This concept is
primarily used to optimize
loading of a target ion, or species, on a material and to reduce overall waste
generation. In some
embodiments the performance of the media is determined by the amount of waste
produced wherein a
smaller amount of waste is indicative of better performance.
Breakthrough Curves
[0039] Figure 1 depicts a typical breakthrough curve that is plotted as final
concentration (C) (effluent)
divided by initial concentration (Co) (influent) with respect to time (t), as
depicted, or voltune (v). This
represents a normalization of the ions with respect to concentration. The
steepness of the breakthrough
curve detennines the extent to which the capacity of a sorbent bed can be
utilized. Thus, the shape of the
curve is instrumental in determining the length of the sorption bed. When the
curve is plotted with respect
to time (t) a steeper curve indicates a quicker reaction which is indicative
of improved operating
efficiency. Improving operating efficiency allows for a larger volume to be
processed in a shorter amount
of time.
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[0040] Figure 2 depicts the relationship between the ion concentration and the
capacity of the media. The
performance of ion exchange media in a column or batch mode is dependent on
the total ion
concentration in the solution, the ion to be separated, and the other ions
that are competing with it. An ion
exchange media also has a maximum theoretical capacity (defined in meq/g or
meq/L), which can only be
met under certain conditions. In normal operating conditions, this capacity is
rarely met due to
competition between ions; this is considered the "active" capacity of the
medium. Based on an Adsorption
Isotherm Model, the maximum capacity of a media can be reached when the
concentrations of the target
ions are high; the total capacity decreases when the concentrations are low.
Given these facts,
concentration techniques can be employed to increase the "active" capacity of
media.
[0041] There are at least three technologies which can be used to concentrate
ions in solution:
nanofiltration, reverse osmosis, and evaporation/crystallization. In each of
these technologies there is a
concentrate stream whereby ions are concentrated as portion of the total
solution and a penneate, or
discharge, stream which has significantly reduced ion concentrations. The
concentrate stream is the
portion of the liquid containing a greater concentration of ions after
processing. In nanofiltration and
reverse osmosis the concentrate stream is the portion of the liquid that does
not pass through the
membrane. In evaporation the concentrate stream is the portion of the liquid
that is not evaporated. The
permeate stream is the portion of the liquid containing a smaller
concentration of ions after processing. In
nanofiltration and reverse osmosis the permeate stream is the portion of the
liquid that passes through the
membrane. In evaporation the permeate stream is the portion of the liquid that
is evaporated. "Permeate"
as used herein specifically refers to the permeate stream that is produced by
one or more ion
concentration technologies.
[0042] The manipulation of ion concentration can be used to maximize uptake on
the media. The use of
one or more ion concentration technologies to increase multivalent ion
concentration to cation media
improves its performance. Figures 3A through 3C graphically depict the
capacity of the media in relation
to the ion concentration and the difference between the use of a concentration
step and without a
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concentration step. Figure 3A is a graph showing the concentration of influent
ions to the capacity of the
media with and without a concentration step when all ions in the liquid are
concentrated equally. Figure
3B is a graph showing a comparison between the concentrations of influent ions
to the capacity of the
media with and without a concentration step wherein the concentration step
results in higher
concentration of one ion with respect to the other ions in the liquid. Figure
3C is the graph of Figure 3B
wherein the concentration step also increases the capacity of the media. When
a first set of ions Xis
concentrated by a factor of A, and a second set of ions Y is concentrated by a
different set of
factors B (wherein B is less than A) the effective capacity of the media to
retain Xis increased.
Figure 4 shows the upward movement of the curve to achieve maximum capacity of
the media and a
concentration step increases the ion to ion exchange (IX) media.
Nanofiltration
[0043] in some embodiments a nanofilter conditioning step is used to increase
the concentration of one
or more select target species (e.g. magnesium, calcium, and strontium, among
others) and improve the
utilization of the ion exchange media. Figure 5 shows an isometric view of an
exemplary nanofilter.
Nanofiltration is a separation process that utilizes diffusion through a
membrane with a typical pore size
between 0.1 to 10 nanometers. Unlike reverse osmosis membranes, nanofilter
membranes operate at
lower pressure and offer selective solute rejection based on size. The
pressure differential between the
two sides of the membrane facilitates the nanofiltration process.
[0044] Application of a nanofilter creates a concentrate stream with greater
concentration of target
species (e.g., magnesium, calcium, and strontium) while allowing monovalent
species to pass to the
permeate stream. In some embodiments, the media loading capacity increases as
the concentration of the
select target species increases. Preliminary testing of the concentrate stream
composition did not show
significant difference in loading capacity from the reduced ratio of
multivalent to monovalent ions.
[0045] Table 1 shows preliminary analyses that illustrate an example
embodiment wherein the ion
exchange media loading capacity is a function of magnesium concentration. As
magnesium concentration
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increases, so does the loading capacity. A similar effect can be achieved for
other target species such as
calcium and strontium. among others.
Removal Cycle Magnesium, Media Capacity
Step # ppm mg/kg media
0 1400 24.22
1 1359 24.03
2 1319 23.86
3 1280 23.69
63 218 19.02
64 212 18.99
65 206 18.96
66 199 18.93
Table 1: Effect of Mg Concentration on Media Capacity
[0046] In some embodiments the nanofilter is a 5:3:2 tube array. In some
embodiments the nanofilter
elements are eight inches in diameter and forty inches in length. In some
embodiments there are six
elements per tube. In some embodiments, the tubes may be twenty-one feet long.
In some embodiments
the Nanofilter skid comprises a three stage array and associated equipment and
may be contained within a
single enclosure. Other configurations are possible and considered.
[0047] In some embodiments more than one nanofilter, or array of nanofilters,
may be used where each
nanofilter, or array of nanofilters, is implemented to concentrate a specific
target species in the liquid. In
some embodiments one or more nanofilters or nanofilter arrays may be mounted
in one or more mobile
skids. In some embodiments one or more Nanofilter skids may be used wherein
each skid may contain
one or more nanofilters and wherein each skid is operable to concentrate a
specific target species in the
liquid. In some embodiments one Nanofilter skid may be used wherein the
Nanofilter skid comprises one
or more nanofilters each operable to concentrate a different target species in
the liquid.
[0048] With respect to projected life for the nanofilter membranes, a properly
designed system (which
requires defined and consistent source liquid chemistry at the inlet) can
operate for many years without
cleaning. Aspects which are considered include maintaining a membrane flux
within acceptable range,
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flow on the concentrate side within acceptable range, and liquid chemistry
managed to minimize solids
formation. Typically, a clean-in-place system may be provided with the
nanofilter to address unexpected
changes in the liquid chemistry. The specific chemicals required for the
cleaning may be dependent on the
projected spikes in the liquid chemistry and the type of scaling which might
occur.
[0049] Another potential situation which may require maintenance is the
presence of suspended solids
that may become entrained in the nanofilter membrane. To address this
situation an inline cartridge filter
is typical for the incoming stream. Other filtration systems may be utilized.
If significant suspended solids
were projected for an embodiment, one or more Solids Removal skids 220 (FIG.
8) comprising one or
more solids removal filters (SRF) may be used to reduce, or remove, the
suspended solids in the process
liquid. Within the membranes, accumulation of solids may be minimized by
controlling chemistry and
designing the system so that an acceptable flow rate is maintained on the
concentrate side of the
membrane.
Reverse Osmosis
[0050] In some embodiments a reverse osmosis conditioning step is used to
increase the concentration of
one or more select target species (e.g. magnesitun, calcitun, and strontium,
among others) and improve
the utilization of the ion exchange media. Reverse osmosis is capable of
separating granular particulate
such as sand, sediment, or other suspended solids, as well as molecular
compounds and ions provided
their physical size is larger than that of the solvent. Application of reverse
osmosis creates a concentrate
stream with greater concentration of ions (e.g., magnesium, calcium, and
strontium) while allowing water
to pass to the permeate stream. In some embodiments, the media loading
capacity increases as the
concentration of the ions in the process liquid increases.
[0051] Osmosis is the spontaneous tendency for water to move concentrations
across a pressure gradient
of high to low. For example, if one gallon of saline water is connected to one
gallon of distilled water and
allowed to sit, after a period of time both gallons would contain an equal
concentration of saline. The
dissolved molecules will balance out across the concentration gradient of high
to low, resulting in two
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equal midpoint concentrations. Reverse osmosis is a forcibly applied inverse
of natural osmosis in which
a single volume of concentrated liquid is separated into solute and solvent.
The process is typically
employed for the desalinization and filtering of drinking water, but can be
applied to most any liquid
processing operation.
[0052] In some embodiments, the process may be accomplished by employing an
outside force such as a
pump, gravity, moving plate, or any other means of applying a force, to the
solvent, and forcing it through
a semi-permeable membrane. The semi-permeable membrane contains holes or gaps
large enough for the
solvent to pass through while leaving the solute behind. In the example
embodiment discussed above, a
high saline concentration solvent is forced through a semi-permeable membrane
comprised of holes large
enough for WO molecules, but small enough to prevent Na + or cr ions from
passing through. These ions
are both larger than an H20 molecule, so any amount can be filtered out of the
solvent regardless of ion
concentration or mass of solute present.
Evaporation/Crystallization
[0053] Evaporation/crystallization is a treatment option that removes liquid
from dissolved solids (as
opposed to other options where the dissolved solids are removed from liquid).
The overall ion
concentration increases because the amount of ions in the liquid remains the
same while the volume of the
liquid decreases. Generally evaporation/crystallization systems are
implemented to completely remove
the liquid from the solids in solution; however, for the systems and methods
disclosed herein it is
beneficial to use evaporation/crystallization systems to reduce the volume of
the liquid resulting in a
solution having a greater concentration of ions. As discussed previously,
increasing the concentration of
ions in solution increases the performance of ion exchange media.
[0054] An embodiment utilizes an evaporation/crystallization system to reduce
volume of source liquid
thus increasing ion concentration in the liquid. This approach does not add
chemicals to precipitate solids.
Depending on the chemistry of the source liquid, the first step in the process
may be pH adjustment and
de-gassing of the liquid stream to remove bicarbonate alkalinity. This
operating step may be done in three
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stages (acidification, de-aeration, re-alkalinization), in some embodiments,
and results in a liquid stream
that protects the downstream evaporator/crystallizer components from scaling.
[0055] The recirculating concentrated slurry may be taken off as a slip stream
to a dewatering system to
produce a 90wt% suspended solids stream, in some embodiments. The liquid
recovered from dewatering
the solids may be recycled through the evaporator/crystallizer and/ or one or
more additional evaporators
and/or crystallizers, in some embodiments.
[0056] In some embodiments processing equipment may be modular. For instance,
the processing
equipment may be contained within a modular enclosure, or skid, much like the
MPS skids. In some
embodiments water treatment flow capacity is 400 n-0/day (16.7 m3/hr). Other
flow rate capacities and
processing equipment are considered. Processing equipment for any flow rate
capacity may be modular in
design. In some embodiments, power consumption for the facility, with
equipment, is estimated to be
about 1100 kW. The power consumption is predominantly for the evaporation
process and thus a function
of the flow rate and not the dissolved solids content. The equipment may
include one or more auxiliary
boiler to produce steam for startup purposes to operate the crystallizer
heater until the vapor generation is
sufficient to drive the crystallizer heater.
Mobile Processing System Overview
[0057] The processing options discussed above, and others not expressly
described herein, may be
mobile or modular in design. In some embodiments the systems and methods
disclosed herein may be
included in mobile modules such as those disclosed in co-pending application
entitled Mobile Processing
System (MPS) for Hazardous and Radioactive Isotope Removal, Ser. No.
14/748,535 filed June 24, 2015,
with a priority date of June 24, 2014, which is herein incorporated by
reference in its entirety.
[0058] The Mobile Processing System (MPS) is designed to be both transported
and operated from
standard sized intermodal containers or custom designed enclosures, referred
to herein as skids or
modules, for increased mobility between sites and on-site, further increasing
the speed and ease with
which the system may be deployed. The system may be completely modular wherein
different modules
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perform different operations in a modular liquid remediation process. The
skids may be connected in
parallel and/or in series in order to perform all of the process requirements
for any given site. A further
advantage of the MPS is the availability of additional modules for further
processing of the contaminants
removed from contaminated liquids such that the contaminants do not need to be
transported from the site
for further processing prior to final disposition.
[0059] The MPS may comprise one or more forms of liquid processing. Depending
on the needs of the
particular site, one or more different processes may be used. In some
embodiments, one or more of the
same modules may be used in the same operation. For instance, two or more
separate ion specific media
(ISM) modules may be used in series and/or in parallel. In some embodiments
one or more ISM modules
in a series may each be operable to remove a specific ion from the waste
stream. Another example is
placing two or more of the same module in parallel to handle an increased flow
capacity or to bring one or
more modules online while one or more others are brought offline for
maintenance. For processes that
take more time, such as feed/blend in some embodiments, it may be advantageous
to place one or more
modules in parallel to reduce overall processing time. Other configuration
variations not expressly
disclosed herein may be implemented.
[0060] Figure 6 is an isometric view of an embodiment of a MPS comprising five
separate skids: a
Control and Solids Feed skid 140, a Feed/Blend skid 130, a Solids Removal
Filter skid 120, an Ultra
Filter skid 110, and an Ion Specific Media (ISM) skid 100. In an embodiment,
the five skids depicted in
Figure 6 can be arranged in different operation modes that allow for
flexibility in accommodating specific
processing needs. Some embodiments may comprise one or more types of skids not
depicted in Figure 6
such as one or more Nanofiltration skids 250 (FIG. 9), Reverse Osmosis skids
(not shown), and
Evaporation/Crystallization skids (not shown). Processing embodiments may
comprise any number and
type(s) of skids as required for the particular application.
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[0061] Figure 7 is a top view of the system of Figure 6.1n an embodiment, the
five skids of Figure 6 are
depicted side by side but do not necessarily have to be in this configuration
on site. In an embodiment, the
skids may be positioned as required by the topography of the site.
[0062] in some embodiments, to minimize the frequency for access to the skids
for Ion Specific Media
(ISM) vessel replacement, the equipment may be configured to use six or more
ISM vessels in series, or
parallel, by connection of two or more ISM modules. The determination of the
number of ISM vessels
required is dependent on the loading capacity of the media, the target
species, and the size of the vessels.
In some embodiments, the loading capacity of the media is a function of the
concentration of the target
species. Preliminary testing indicates higher loading capacity for higher
magnesium concentration, for
instance.
[0063] Figure 8 depicts an example configuration of four MPS skids: a Powder
Feed/Controls skid 240, a
Feed Blend skid 230, a Solids Removal skid 220, and an ISM skid 200. The
Solids Removal skid 220
with the solid removal filters may be used to protect the ion exchange columns
with the aim of accounting
for the potential presence of suspended solids. The ISM skid 200 may be
configured to utilize one or
more ISM vessels in series and/or in parallel. Some embodiments utilize more
than one ISM skid 200 in
series and/or in parallel. The configuration, type, and number of skids may
vary between embodiments.
Processing may continue until a target residual ion concentration is attained
for one or more
target species.
[0064] In some embodiments, the selected endpoint is magnesium removal until
the residual magnesium
concentration is 200 ppm or less, which may then be treated by other treatment
systems, if necessary to
meet certain regulations, standards, and/or requirements. The amount of media
required is based on the
desired end concentrations of one or more target species. In some embodiments
the process liquid may be
continuously cycled through the system until it meets process or other
requirements. In some
embodiments the process liquid may proceed to secondary processing where it
may be treated by other
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low concentration treatment systems; if necessary to meet certain regulations,
standards, and/or
requirements.
[0065] The system may incorporate a number of valves. The valves may be of one
or more different
types. Check valves may be used through the system to prevent flow from
flowing backwards. Many of
the valves may be motor operated to allow for quick shutoff or open as
necessary to prevent leaks or
reduce pressure. Pressure relief valves may be used to automatically release
pressure when the system
pressure exceeds a predetermined value. Motor operated valves may be designed
to fail as-is, open, or
closed depending on their location in the system to minimize damage and
environmental hazards in the
event of failure. Redundant valves may be used throughout the system to
provide additional control and
increase the factor of safety of the system, reducing the possibility of
leakage to the environment in the
event of a failure. Valves are disclosed in more detail in co-pending
application entitled Mobile
Processing System for Hazardous and Radioactive Isotope Removal, Ser. No.
14/748,535 filed June 24,
2015, with a priority date of June 24, 2014, which is herein incorporated by
reference in its entirety.
Concentration Step Followed by MPS
[0066] In some embodiments the concentrate stream may be processed using a
Mobile Processing
System (MPS). Figure 9 depicts an embodiment utilizing a Nanofilter skid 250
as a form of a
conditioning step that is incorporated into the MPS configuration of Figure 8.
Some embodiments may
comprise one or more Reverse Osmosis skids, Evaporation/Crystallization skids;
and/or Nanofilter skids
250 for ion concentration. The configuration, type, and number of skids may
vary between embodiments.
The Nanofilter skid 250 is used for further embodiment descriptions as the
example concentration
method; however it should be noted that other concentration methods may be
used. The Nanofilter skid
250 separates the source liquid into a permeate stream and a concentrate
stream. The concentrate stream
containing the greater concentration of multivalent species is sent to MPS, in
the depicted embodiment. In
some embodiments the permeate stream may be processed, stored, reused, or
released to the environment
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depending on the types and concentrations of contaminants remaining in the
liquid. In some embodiments
the permeate stream may be processed by MPS.
[0067] In an embodiment one or more Solids Removal skids 220 may be used at
one or more points in
the system to reduce the possibility of any potential solids from fouling the
systems. The number and
location(s) of Solids Removal skids 220 required for a given embodiment is
dependent on the suspended
solids content in the process liquid. The level of suspended solids may be
small in some embodiments
because the inlet may be filled by decanting liquid from an evaporator
collection tank. In some
embodiments, the number of Solids Removal skids 220 may be as low as one or
two when the MPS
process does not include powder addition.
[0068] Figure 10 depicts the embodiment of Figure 9 wherein both the
concentrate stream and permeate
stream from the Nanofilter skid 250 proceed to an ISM skid (200a and 200b,
respectively). The
concentrate stream and the permeate stream will contain differing target
species and concentrations
thereof. Each ISM skid 200a and 200b is operable to remove one or more target
species present in the
stream it receives for processing.
[0069] Figure 11 depicts an embodiment that utilizes the Nanofilter skid 250
to process the source liquid
into a Permeate Collection Tank 310 and Concentrate Collection Tank 320. In
this embodiment, the
filtered liquid containing the monovalent species is sent to the Permeate
Collection Tank 310 while the
concentrate stream containing the multivalent species is sent to the
Concentrate Collection Tank 320. In
some embodiments, one or both of the liquid streams exiting the Nanofilter
skid 250 may be processed,
stored, reused, or released to the environment depending on the types and
concentrations of contaminants
remaining in the liquid.
[0070] The liquid in the Concentrate Collection Tank 320 may be higher in
target species concentration
(compared to the source liquid concentration), which may improve the
effectiveness of the media.
Recirculation through the MPS skids and back to the Concentrate Collection
Tank 320 may allow for
more complete use of the media capacity. The projected chemistry for the
Concentrate Collection Tank
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320, in some embodiments, is not near the saturation point for one or more
target species; therefore, solids
are not expected from the concentration operation.
[0071] The projected composition of selected components in an embodiment for
the Permeate Collection
Tank 310 and Concentrate Collection Tank 320 is shown in Table 2, and an
example of source liquid
composition is provided for reference. A nanofilter system or skid may be
designed to achieve 75%
permeate recovery, in some embodiments.
Component Source Liquid Permeate Tank, ppm Concentrate
Tank, ppm
Calcium 120 30 390
Magnesium 1400 145 5161
Strontium (total) 3.7 0.9 11.8
Sodium 5865 5671 6443
Chloride 12490 9333 21945
Table 2: Projected Composition of Permeate and Concentrate Tanks
[0072] Figure 12A depicts an embodiment that utilizes an ISM skid 200 to
capture one or more target
species from the concentrate stream. Since the amount of liquid to be
processed is directly proportional to
the amount of ion exchange media needed in some embodiments, the use of the
Nanofilter skid 250 aids
in reducing the amount of the liquid to be treated by filtering out the
permeate stream that is sent to the
Permeate Collection Tank 310, in the depicted embodiment; hence, maximizing
the use of the ion
exchange media and reducing the amount of ISM vessels needed. In some
embodiments the concentrate
stream may pass directly from the Nanofilter skid 250 to the ISM skid 200. In
some embodiments the
permeate stream may pass directly from the Nanofilter skid 250 to a separate
ISM skid 200.
[0073] Some embodiments may utilize one or more of each skid. In some
embodiments more than one
concentration skid may be used wherein each concentration skid is used to
concentrate a different
particular target species. In some embodiments the system may comprise more
than one ISM skid 200
wherein each ISM skid 200 may be specific to different particular target
species. In some embodiments
both the concentrate stream and the permeate stream may proceed to separate
ISM skids 200 wherein
each ISM skid 200 is operable to remove one or more particular target species
present in each stream.
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[0074] In some embodiments the source liquid may have been previously
processed. In some
embodiments the source liquid may have been previously processed for a
different target species prior to
processing in the depicted systems. In some embodiments the source liquid is a
concentrate stream. In
some embodiments the source liquid is a permeate stream. Some embodiments may
comprise a series of
Nanofilter skid 250 and ISM skid 200 pairs wherein each pair is operable to
process a particular target
species. In some embodiments the processed liquid exiting the ISM skid 200 may
proceed through one or
more systems of Nanofilter skid 250 and ISM skid 200 pairs wherein each pair
is operable to process a
different target species. In some embodiments the permeate stream may be
stored in a Permeate
Collection Tank 310, proceed directly to other processing or storage systems,
or be released if it meets
release standards.
[0075] Figure 12B depicts the embodiment of Figure 12A with example flow rates
and tank volumes. In
this example embodiment, a 7500 m3 Permeate Collection Tank 310 is used for
receiving the permeate
stream from the Nanofilter skid 250 while a 25001113 Concentrate Collection
Tank 320 is used for
receiving the concentrate stream. In the depicted embodiment, a source liquid
may be supplied to the
Nanofiltration skid 250 at 220 gpm; the permeate stream may be delivered to
the Permeate Collection
Tank 310 at 165 gpm while the concentrate stream may be delivered to the
Concentrate Collection Tank
320 at 55gpm. The same or similar flow rates may be applied to other
configurations. Other embodiments
may have different flow rates and tank voluines.
Precipitation
[0076] Another alternate method of increasing ion exchange media capacity is
precipitation.
Precipitation is different than nanofiltration, reverse osmosis, and
evaporation/crystallization in that it
results in a concentrate stream containing the target species and one or more
precipitated solids instead of
a permeate stream. In an embodiment, a precipitation agent may be added to
facilitate the extraction of
one or more precipitants. Precipitation of one or more solids from solution
increases the ratio of the
remaining target species with respect to the precipitant species such that the
driving force to reach
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equilibrium is increased by reducing the relative competition from the
precipitant species. This increase in
driving force results in more effective use of the ion exchange media thus
increasing the capacity of the
media.
[0077] Figure 13 depicts a generic embodiment of a precipitation process that
involves the addition of a
precipitation agent for the removal of one or more precipitant. In the
depicted embodiment a Precipitation
skid 375 follows a Nanofilter skid 250 prior to an ISM skid 200. In the
depicted embodiment the
permeate stream is routed to a Permeate Collection Tank 310. In some
embodiments the permeate stream
may be processed, stored, reused, or released to the environment depending on
the types and
concentrations of contaminants remaining in the liquid.
[0078] In an embodiment, the concentrations of one or more target species,
such as magnesium, calcium,
and strontium, in the concentrate stream can be significantly reduced with the
use hydroxide precipitation.
The difference in solubility and precipitation pH can be used to selectively
extract and reduce the amount
of one or more target species.
[0079] Figure 14 depicts the precipitation process embodiment of Figure 13
where the precipitation
agent is a hydroxide. In the depicted embodiment hydroxide ions are introduced
to the concentrate stream
containing the metals to be extracted aiding in the precipitation of a target
species such as magnesium,
calcium, and/or strontium. Metals precipitate at various pH levels depending
on the form of the metal,
chemistry of the source liquid, and presence of other metals and chelates. As
such the manipulation of the
hydroxide ion concentration in the liquid adjusts the pH and readily
precipitates the metals in form of
metal hydroxide compounds. The pH level can be adjusted to target specific
species. The pH may need to
be carefully controlled because some metals are amphoteric in nature and the
presence of chelating agents
can also interfere with the ability for metals to precipitate.
[0080] The addition of a strong base such as sodium hydroxide may facilitate
the formation of
magnesium hydroxide, in some embodiments. In some embodiments magnesium
hydroxide is the
targeted precipitant though strontium hydroxide and calcium hydroxide may also
form. Magnesium
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hydroxide is the more insoluble than strontium hydroxide and calcium hydroxide
regardless of liquid
temperature and has a lower precipitation pH of 9-10 so it is likely to
precipitate first. Both strontium
hydroxide and calcium hydroxide are slightly soluble in the same pH ranee as
magnesium but most likely
will not precipitate. An increase of the pH may result in the precipitation of
strontium hydroxide and
calcium hydroxide, since both have a solubility pH around 12.
[0081] The difference in the solubility of strontium hydroxide and calcium
hydroxide can be used to
selectively extract one from the other. This means that the relationship
between solubility and temperature
may be used to precipitate one while the other remains the liquid. The
solubility of strontium hydroxide is
directly proportional to temperature; hence, lowering the temperature of the
liquid would decrease the
solubility of strontium hydroxide and increase its precipitation rate. The
solubility of calcium hydroxide is
inversely proportional to temperature; hence, increasing the temperature of
the liquid would decrease the
solubility of calcium hydroxide and increase its precipitation rate.
[0082] Calcium hydroxide being more insoluble than strontium hydroxide would
likely precipitate after
magnesium hydroxide and before strontium hydroxide with an increase in pH of
the stream to around 12,
depending on temperature of the process liquid. An increase in temperature of
the liquid may improve the
efficiency of calcium hydroxide precipitation, while the strontium hydroxide
becomes more soluble and
remains in solution. In some embodiments the remaining strontium in solution
may be concentrated in a
nanofiltration step and removed in an ion exchange step.
[0083] In an embodiment, after the precipitation of magnesium hydroxide and
calcium hydroxide, the
concentrate stream may be cooled to facilitate the precipitation of the
strontium hydroxide. Generally, the
precipitation of strontium hydroxide occurs when the temperature of the
solution is around 25 C to 30 C.
If the strontium hydroxide precipitation upon cooling isn't sufficient, carbon
dioxide gas can be
introduced into the solution to increase the efficiency of the strontium
hydroxide precipitation.
[0084] In an embodiment, the advantage of using sodium carbonate and/or sodium
hydroxide in the
removal of magnesium, calcium, and strontium is that the remaining sodium in
the liquid may be
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crystallized with the chlorides (as shown on Table 2) to form sodium chloride
salt. The precipitants can
then be recovered with the use of conventional processes such as filtering.
[0085] For the sake of convenience, the operations are described as various
interconnected functional
blocks or distinct software modules. This is not necessary, however, and there
may be cases where these
functional blocks or modules are equivalently aggregated into a single logic
device, program or operation
with unclear boundaries. In any event, the functional blocks and software
modules or described features
can be implemented by themselves, or in combination with other operations in
either hardware or
software.
[0086] Having described and illustrated the principles of the systems,
methods, processes, and/or
apparatuses disclosed herein in a preferred embodiment thereof, it should be
apparent that the systems,
methods, processes, and/or apparatuses may be modified in arrangement and
detail without departing
from such principles. Claim is made to all modifications and variation coming
within the spirit and scope
of the following claims.
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