U.S. patent application number 15/269349 was filed with the patent office on 2017-01-05 for fluid treatment methods and systems.
This patent application is currently assigned to EnergySolutions, Inc.. The applicant listed for this patent is EnergySolutions, Inc.. Invention is credited to Lu Liu, Tim Milner, Paul Sylvester.
Application Number | 20170001890 15/269349 |
Document ID | / |
Family ID | 51258387 |
Filed Date | 2017-01-05 |
United States Patent
Application |
20170001890 |
Kind Code |
A1 |
Milner; Tim ; et
al. |
January 5, 2017 |
Fluid Treatment Methods and Systems
Abstract
Methods and systems for treatment of wastewater. In some
embodiments, the system may comprise one or more modules such as an
electrochemical module, an electrocoagulation module, a flotation
module, an evaporation module, and an ultrafiltration module. One
or more detection modules may also be provided to analyze the
concentration of one or more wastewater components in the
wastewater. Data from such modules may be used to adjust one or
more operational parameters or conditions in the treatment system.
The system may also comprise one or more features designed to
minimize adverse effects on the environment, such as avoiding
adding chemicals to the stream, extracting salt or other chemicals
for re-use, and/or use of carbon dioxide gas from on-site
combustion processes.
Inventors: |
Milner; Tim; (Lexington,
SC) ; Liu; Lu; (Lexington, SC) ; Sylvester;
Paul; (Waltham, MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
EnergySolutions, Inc. |
Salt Lake City |
UT |
US |
|
|
Assignee: |
EnergySolutions, Inc.
Salt Lake City
UT
|
Family ID: |
51258387 |
Appl. No.: |
15/269349 |
Filed: |
September 19, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14174499 |
Feb 6, 2014 |
9446974 |
|
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15269349 |
|
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61761607 |
Feb 6, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C02F 2103/10 20130101;
C02F 2209/06 20130101; C02F 1/463 20130101; C02F 1/66 20130101;
C02F 1/4672 20130101; C02F 1/444 20130101; C02F 2209/005 20130101;
C02F 11/006 20130101; C02F 1/441 20130101; C02F 1/24 20130101; C02F
1/04 20130101; C02F 9/00 20130101; C02F 1/40 20130101; C02F 2101/32
20130101 |
International
Class: |
C02F 1/66 20060101
C02F001/66; C02F 1/04 20060101 C02F001/04; C02F 1/467 20060101
C02F001/467; C02F 1/44 20060101 C02F001/44; C02F 1/463 20060101
C02F001/463; C02F 1/24 20060101 C02F001/24; C02F 1/40 20060101
C02F001/40 |
Claims
1-13. (canceled)
14. A method for treating wastewater comprising: analyzing the
composition of the wastewater in real-time to produce real-time
data; modifying one or more modules or parameters in a wastewater
treatment system using the real-time data; and increasing a pH of
the wastewater using an electrochemical treatment process and
without adding any chemicals to the wastewater.
15. The method of claim 14 wherein the composition of the
wastewater is analyzed before the water is treated by the
wastewater treatment system.
16. The method of claim 14 wherein analyzing the composition of the
wastewater includes analyzing the composition of the wastewater
using Laser-Induced Breakdown Spectroscopy.
17. The method of claim 14 wherein analyzing the composition of the
wastewater includes analyzing the concentration of one or more
constituents in the wastewater.
18. The method of claim 14 wherein modifying one or more modules or
parameters in the wastewater treatment system comprises at least
one of disabling one or more modules in the wastewater treatment
system, adjusting an operational parameter of one or more modules
in the wastewater treatment system, diverting the wastewater to
bypass one or more modules in the wastewater treatment system, or
recirculating the wastewater through one or more modules in the
wastewater treatment system.
19. The method of claim 14 wherein analyzing the composition of the
wastewater includes measuring the pH of the wastewater.
20. The method of claim 19 comprising comparing the pH of the
wastewater to a pH threshold.
21. The method of claim 20 wherein the pH threshold is
approximately 11 and increasing the pH of the wastewater includes
increasing the pH of the wastewater to be approximately 11 to
approximately 12.
22. The method of claim 14 wherein the electrochemical treatment
process includes an electrocoagulation process.
23. The method of claim 14 wherein the electrochemical treatment
process includes an electro-oxidation process.
24. The method of claim 14 wherein analyzing the composition of the
wastewater includes measuring the concentration of at least one
alkaline earth metal in the wastewater.
25. A method for treating wastewater at a fracking site comprising:
measuring the concentration of at least one alkaline earth metal in
wastewater from a fracking operation, the wastewater including oil;
comparing the concentration of the at least one alkaline earth
metal to a threshold and adjusting a pH of the wastewater to be
approximately 11 to approximately 12 using an electrochemical
treatment process if the concentration of the at least one alkaline
earth metal exceeds the threshold; treating the wastewater using at
least one of electrocoagulation, dissolved air flotation treatment,
precipitation of scale forming elements using carbon dioxide gas,
or ultrafiltration.
26. The method of claim 25 wherein measuring the concentration of
at least one alkaline earth metal in the wastewater includes
measuring the concentration of at least two alkaline earth metals
in the wastewater.
27. The method of claim 25 wherein measuring the concentration of
at least one alkaline earth metal in the wastewater includes
measuring the concentration of calcium in the wastewater and
measuring the concentration of magnesium in the wastewater
28. The method of claim 27 wherein comparing the concentration of
the at least one alkaline earth metal to a threshold includes
comparing the concentration of calcium in the wastewater to a first
threshold and comparing the concentration of magnesium in the
wastewater to a second threshold and adjusting the pH of the
wastewater to be approximately 11 to approximately 12 using the
electrochemical treatment process if either the concentration of
calcium exceeds the first threshold or the concentration of
magnesium exceeds the second threshold.
29. The method of claim 28 wherein the first threshold is
approximately 1000 mg/L.
30. The method of claim 28 wherein the second threshold is
approximately 500 mg/L.
31. The method of claim 25 wherein the threshold is at least about
50 mmol/L.
32. The method of claim 25 comprising determining that oil and/or
the at least one alakaline earth metal is present in the
wastewater.
Description
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS
[0001] This is a divisional of U.S. patent application Ser. No.
14/174,499, titled "Fluid Treatment Methods and Systems," filed on
6 Feb. 2014, issued as U.S. Pat. No. 9,446,974, which claims the
benefit of U.S. Provisional Pat. App. No. 61/761,607, titled "Fluid
Treatment Methods and Systems," filed on 6 Feb. 2013, all of which
are incorporated by reference into this document in their entirety.
In the event of a conflict, the subject matter explicitly recited
or shown in this document controls over any subject matter
incorporated by reference. The incorporated subject matter should
not be used to limit or narrow the scope of the explicitly recited
or depicted subject matter.
SUMMARY
[0002] Disclosed herein are embodiments and implementations of
methods and systems for treatment of fluids, such as wastewater
from a fracking site. In some embodiments, the system may comprise
one or more modules such as an electro-oxidation module, an
electrocoagulation module, a flotation module, an evaporation
module, and an ultrafiltration module. One or more detection
modules may also be provided to analyze the concentration of one or
more wastewater components in the wastewater. Data from such
modules may be used to adjust one or more operational parameters or
conditions in the treatment system. The system may also comprise
one or more features designed to minimize adverse effects on the
environment, such as avoiding adding chemicals to the stream,
extracting salt or other chemicals for re-use, and/or use of carbon
dioxide gas from on-site combustion processes.
[0003] In one particular example of a system for treatment of
wastewater, a wastewater feed port configured to receive an
incoming stream of wastewater may be provided. The system may
further comprise an electro-oxidation module configured to receive
an incoming wastewater stream and increase the pH of the wastewater
stream passing therethrough. In some embodiments, one or more of
the modules may be configured to increase the pH of the wastewater
stream to between about 11 and about 12. In some embodiments, the
pH of the stream may be increased without adding chemicals to the
water.
[0004] An electrocoagulation module may also be provided comprising
at least two electrodes. The electrocoagulation module may be
configured to receive an incoming wastewater stream and remove one
or more contaminants from the wastewater stream passing
therethrough. In some embodiments, the electro-oxidation module and
the electrocoagulation module may be part of a single combined
electrochemical treatment unit.
[0005] The system may further comprise a flotation module
configured to receive and separate an incoming wastewater stream
into an aqueous phase stream and one or more other streams, such as
an oil phase stream, a sludge phase stream, and/or a stream
comprising oil and solid particles. An evaporation module may be
configured to receive the aqueous phase stream from the flotation
module and further configured to precipitate scale-forming elements
within the aqueous phase stream. In some embodiments, the flotation
module may further be configured to skim coagulated oil from the
surface of the wastewater stream entering the flotation module.
[0006] In some embodiments, the system may further comprise a
carbon dioxide line configured to deliver carbon dioxide gas to the
evaporation module. In some such embodiments, the carbon dioxide
gas delivered to the carbon dioxide gas line may be generated from
exhaust resulting from the combustion of hydrocarbon fuels at a
treatment site of the system for treatment of wastewater. For
example, the carbon dioxide gas delivered to the carbon dioxide gas
line may be generated from exhaust resulting from the combustion of
hydrocarbon fuels by one or more modules of the treatment
system.
[0007] An ultrafiltration module may be configured to receive an
incoming stream and deliver an outgoing stream of permeate
comprising a salt solution, such as a solution comprising sodium
chloride salt and/or one or more other salts. Such solution may, in
some embodiments, be further processed, such as by way of a thermal
processing module, to obtain a reusable salt product. Such a
thermal processor may be configured to receive an incoming stream
comprising a concentrated NaCl solution from an ultrafiltration
module and deliver a solid NaCl at first port and a purified stream
of water at a second port.
[0008] In some embodiments, a Reverse Osmosis (RO) module may also
be included. This may be useful to separate an incoming stream into
outgoing streams comprising one or more high-TDS streams and one or
more low-TDS streams. The high-TDS stream may be sent to an
evaporator, such as a thermal processor, to produce one or more
solid products, such as a solid sodium chloride salt product, if
desired.
[0009] One or more detection modules, such as Laser Induced
Breakdown Spectroscopy modules, may also be provided that may be
configured to analyze the concentration of one or more chemical
components in the wastewater. Such detection module(s) may further
be configured to transmit data to one or more other modules in the
system to adjust one or more operational parameters or conditions
in the system, such as disabling one or more modules in the
wastewater treatment system, adjusting an operational parameter of
one or more modules in the wastewater treatment system, diverting a
stream of wastewater to bypass one or more modules in the
wastewater treatment system, or recirculating the wastewater
through one or more modules in the wastewater treatment system.
[0010] In some embodiments, one or more detection modules may be
positioned and configured to detect a pH of wastewater before the
wastewater enters the electro-oxidation module. In some such
embodiments, the system may be configured to disable the
electro-oxidation module and/or divert the wastewater stream to
avoid the electro-oxidation module and/or the electrocoagulation
module upon detecting a threshold pH of wastewater before the
wastewater enters the electro-oxidation module. In some
embodiments, this threshold may be about 11, and the
electro-oxidation module and/or electrocoagulation module may be
configured to increase the pH of the wastewater stream to between
about 11 and about 12 upon receiving an indication from the
detection module that the wastewater stream has a pH below the
threshold.
[0011] In some embodiments, the system may comprise a mobile
wastewater treatment system configured to allow for transporting
the wastewater treatment system to a plurality of distinct
treatment sites. For example, the mobile wastewater treatment
system may comprise at least one of a trailer and a motor
vehicle.
[0012] In a particular example of a method for treatment of
wastewater, the method may comprise receiving an incoming stream of
wastewater in a wastewater feed port, gathering real-time data from
the wastewater comprising at least one of data concerning the
constituents in the wastewater and a concentration of one or more
constituents in the wastewater, and using the real-time data to
determine whether to modify one or more modules or parameters in a
wastewater treatment system. Upon determining from the real-time
data that one or more modules or parameters in the wastewater
treatment system should be modified, the method may further
comprise modifying one or more modules or parameters in the
wastewater treatment system. The step of gathering real-time data
from the wastewater may be performed using, for example, Laser
Induced Breakdown Spectroscopy technology.
[0013] The method may further comprise increasing a pH of the
wastewater. In some implementations, the step of increasing a pH of
the wastewater may be performed using an electrochemical treatment
method, and the step of increasing a pH of the wastewater may be
performed without adding any chemicals to the wastewater.
[0014] In some implementations, the step of receiving an incoming
stream of wastewater in a wastewater feed port may be performed
after the step of gathering real-time data from the wastewater.
[0015] In some implementations, the step of modifying one or more
modules or parameters in the wastewater treatment system may
comprise at least one of disabling one or more modules in the
wastewater treatment system, adjusting an operational parameter of
one or more modules in the wastewater treatment system, diverting a
stream of wastewater to bypass one or more modules in the
wastewater treatment system, and recirculating the wastewater
through one or more modules in the wastewater treatment system.
[0016] In some implementations, the step of gathering real-time
data from the wastewater may comprise assessing a pH level of the
wastewater to determine whether the pH level meets a threshold,
such as 11. In some such implementations, the step of increasing a
pH of the wastewater may comprise increasing the pH of the
wastewater to between about 11 and about 12.
[0017] In a specific example of a method for treatment of
wastewater at a fracking site, the method may comprise receiving an
incoming stream of wastewater from a fracking operation, confirming
the presence of oil within the wastewater, and, upon confirming the
presence of oil within the wastewater, determining whether one or
more alkaline earth metals, such as Ca, Mg, Sr, and Ba, is present
in the wastewater beyond a particular threshold concentration.
[0018] Upon confirming that the threshold has been exceeded, the pH
level of the water may be increased. In some embodiments, the pH
level may be increased to between about 11 and about 12 using an
electrochemical treatment method.
[0019] Upon confirming that the threshold has not been exceeded,
the step of adjusting a pH level of the water may be bypassed.
Following the step of either adjusting a pH level of the water or
bypassing the step of adjusting a pH level of the water, the water
may be sent through at least one treatment process comprising at
least one of electrocoagulation, electro-oxidation, dissolved air
flotation treatment, precipitation of scale-forming elements using
carbon dioxide gas, and ultrafiltration.
[0020] In some implementations, the method may comprise determining
whether Ca is present in the wastewater and determining whether the
Ca in the wastewater exceeds a first threshold. The method may
further comprise determining whether Mg is present in the
wastewater and determining whether the Mg in the wastewater exceeds
a second threshold. In some implementations, the first threshold
may comprise about 1000 mg/L, and the second threshold may comprise
about 500 mg/L.
[0021] Upon confirming that at least one (or, in some
implementations, both) of the first and second thresholds has been
exceeded, the method may further comprise adjusting a pH level of
the water to between about 11 and about 12. This may be performed,
in some implementations, using an electrochemical treatment
method.
[0022] Upon confirming that at least one of the first threshold and
the second threshold has not been exceeded, the step of adjusting a
pH level of the water may be bypassed. In some embodiments, the
step of adjusting a pH level of the water may not be bypassed
unless both the first threshold and the second threshold have not
been exceeded.
[0023] Following the step of either adjusting a pH level of the
water or bypassing the step of adjusting a pH level of the water,
the water may be sent through one or more of the treatment
processes disclosed herein, such as, for example,
electrocoagulation, dissolved air flotation treatment,
precipitation of scale-forming elements using carbon dioxide gas,
and ultrafiltration.
[0024] In some embodiments, if a concentration of carbon greater
than a particular threshold or a concentration of total alkaline
earth metals (Ca, Mg, Sr, and Ba, for example), or one or more such
alkaline earth metals, is less than another particular threshold,
electro-oxidation may be bypassed by either disabling an
electro-oxidation module or diverting the stream around this
module. For example, in some embodiments, upon detecting a
concentration of carbon at a threshold of about 600 mg/L and/or
detecting a concentration of alkaline earth metals below about 50
mmol/L, electro-oxidation may be bypassed.
[0025] In some embodiments, a threshold concentration or
concentrations may be associated with particular alkaline earth
metals. For example, in some embodiments, detecting a concentration
of calcium less than a particular threshold, such as about 800 mg/L
in one preferred embodiment, and about 1000 mg/L in another
preferred embodiment, may be used, in some embodiments in
combination with assessing the concentration of carbon, to
determine whether to bypass electro-oxidation. However, if the
carbon detected in the wastewater stream is below a threshold and
the alkaline earth metal concentration (or one or more such
alkaline earth metals) is above another threshold,
electro-oxidation may be performed and electrocoagulation may
instead be bypassed by either disabling an electrocoagulation
module or diverting the stream around this module.
DRAWINGS
[0026] The written disclosure herein describes illustrative
embodiments that are non-limiting and non-exhaustive. Reference is
made to certain of such illustrative embodiments that are depicted
in the figures, in which:
[0027] FIG. 1 is a schematic diagram of one embodiment of a system
for treatment of a fluid, such as wastewater.
[0028] FIG. 2 is a flow chart of one implementation of a method for
treatment of a fluid, such as wastewater.
[0029] FIG. 3 is a flow chart of another implementation of a method
for treatment of a fluid, such as wastewater.
[0030] FIG. 4 is a flow chart of yet another implementation of a
method for treatment of wastewater at a fracking site.
DETAILED DESCRIPTION
[0031] Embodiments may be best understood by reference to the
drawings, wherein like parts are designated by like numerals
throughout. It will be readily understood that the components of
the present disclosure, as generally described and illustrated in
the drawings herein, could be arranged and designed in a wide
variety of different configurations. Thus, the following more
detailed description of the embodiments of the apparatus is not
intended to limit the scope of the disclosure, but is merely
representative of possible embodiments of the disclosure. In some
cases, well-known structures, materials, or operations are not
shown or described in detail in order to avoid obscuring aspects of
the disclosure. Furthermore, the described features, structures,
steps, or characteristics may be combined in any suitable manner in
one or more alternative embodiments and/or implementations.
[0032] The present disclosure provides various embodiments and
implementations of methods and systems for treatment of a fluid,
such as, for example, wastewater in the oil and gas industries.
More specific examples of contexts in which the inventive methods
and systems described herein may be employed include, for example,
frac flowback water treatment, produced water treatment, and
steam-assisted gravity drainage (SAGD) water treatment.
[0033] In some embodiments and implementations, one or more steps
and/or units may be provided by way of one or more mobile treatment
units. In some embodiments, the entire system may comprise a mobile
treatment system. For example, a mobile water treatment system may
be configured to both transport and treat a fluid, such as
wastewater. Alternatively, such systems may be configured to
provide mobile treatment but not transportation. In other words,
the system may be configured to treat and dispense water at a usage
site.
[0034] Some mobile systems may comprise, for example, a trailer
and/or a motor vehicle. Some such systems may comprise one or more
fluid storage containers, one or more fluid treatment units, and/or
one or more fluid delivery pumps. In some embodiments, the fluid
treatment systems may be incorporated into the fluid storage
containers, such that wastewater, for example, may be treated while
it is contained in a fluid storage container.
[0035] Some embodiments may also be modular, such that one or more
modular units may be replaced individually within the system. Some
embodiments may be both mobile and modular, such that the entire
system, or at least a portion of the system, is provided on a
mobile device, such as a trailer or vehicle, and such that one or
more units in the system may be modular to allow for selective
replacement of individual treatment units within the system.
[0036] Some embodiments may be configured to function by way of
sustainable, relatively low energy input. Some embodiments may
further be configured so as to be environmentally benign. For
example, some embodiments may provide for wastewater treatment
while also providing a low carbon footprint compared to alternative
systems.
[0037] Some embodiments may further provide for the reclamation of
resources from waste streams, such as those resulting from oil and
gas production, in order to render the waste streams suitable for
reuse, recovery, or disposal as environmentally-benign waste
forms.
[0038] Some embodiments may comprise the use of carbon dioxide gas
as a source of carbonate in the selective removal and recovery of
certain substances, such as radium and other alkaline earth metals.
In some embodiments, carbon dioxide may be provided as waste gas
from another process (e.g., the combustion of hydrocarbon fuels)
and fed into such a system or module rather than being discarded.
This may contribute to the environmentally-friendly aspects of
various embodiments of the invention by reducing carbon emissions,
for example.
[0039] As discussed in greater detail below, some embodiments may
employ one or more electrochemical processes. By doing so,
treatment processes may, in some embodiments and implementations,
be provided that are free from chemical agent additives. This may
thereby further reduce the negative impact to the environment, such
as by, in some embodiments, further reducing the carbon footprint
associated with the production and/or transport of chemical agents
to a processing site.
[0040] Some embodiments may be configured to recycle wastewater to
allow for reuse in, for example, the oil and gas industry. In other
words, some embodiments may allow for use of treated wastewater in
one or more post-treatment steps, processes, or systems. The
wastewater from such steps, processes, or systems may then, in some
embodiments, be input back into a treatment process/system such
that water may be continually reused, treated, and then used again
without wasting water along the way. In some embodiments, the
recycling may be tailored to meet a specified reuse criteria. For
example, some embodiments may be configured to produce treated
water that meets federal regulations for drinking water, or that
meets the criteria of a particular permit.
[0041] Some embodiments may be configured to produce sodium
chloride as a treatment byproduct. In some such embodiments, an
aqueous stream of sodium chloride may be provided as a treatment
byproduct. Some such embodiments may be configured such that the
sodium chloride stream comprises a concentrated, purified sodium
chloride aqueous stream. In such embodiments, subsequent thermal
processing may also be provided so as to produce a useful resource,
such as road salt. The finished salt product in such systems may be
usable in other processing steps/systems or, alternatively, may be
stored for sale or use in other systems/processes.
[0042] Some embodiments and implementations may be configured to
reduce and/or minimize the amounts of heavy metal hydroxide
byproducts. Instead, such systems and methods may be configured to
provide useful byproducts that can either be reused, stored for
later sale, or will otherwise be less damaging to the environment.
For example, some embodiments may be configured to provide a
concentrated source of alkaline earth carbonates as a
byproduct.
[0043] Some embodiments may be configured for the partitioning of
waste into a plurality of separate waste streams. Such partitioning
may provide for beneficial reuse or production of environmentally
benign waste that requires no additional chemical agents.
[0044] Some embodiments and implementations may comprise use of a
porous membrane in, for example, a crossflow filtration
process/system. Some such embodiments may comprise crossflow
ultrafiltration processes/systems. In some embodiments, the porous
membrane provided may comprise a ceramic material. Alternatively,
the porous membrane may comprise a sintered metal or polymeric
construction. Irrespective of the materials used, some embodiments
may be configured to effectively separate solid products for
recycle from aqueous streams by way of the aforementioned crossflow
filtration. Other embodiments and implementations may comprise use
of one or more other types of filtration, such as sand
filtration.
[0045] Some embodiments and implementations may further comprise
use of in-situ electrochemically-generated oxidants such as, for
example, sodium hypochlorite. Such electrochemically-generated
oxidants may, in some embodiments, be obtained from a waste steam,
such as a waste brine feed stream, and/or a waste hydroxide
stream.
[0046] Some embodiments may further comprise removal of silica.
Such removal may be accomplished via electrocoagulation in some
embodiments. In such embodiments, downstream barrier filtration
devices may be protected from silica fouling.
[0047] Some embodiments may comprise electrochemical mineralization
of water soluble organic pollutants. Some embodiments may also, or
alternatively, comprise separation of heavy oil via entrained gas
floatation, thereby removing these particles from cross
contamination of subsequent process production of viable resources
for reuse.
[0048] Some embodiments may further comprise a methodology for
raising the pH of the waste solution. In some such embodiments,
electrochemical treatment methods may be used in order to avoid the
need for transporting chemicals to the treatment site.
[0049] Some embodiments and implementations may further comprise
the use of one or more low energy evaporative techniques. In some
such techniques, one or more hydrocavitation processes may be
employed. Since such processes are typically performed without need
for chemical additives, they may further enhance the ability of the
system to avoid harming the environment, and enhance the ability of
the system to allow for recycling/reuse of wastewater following
treatment. Such systems may also be used to kill bacteria and
reduce corrosion of certain components of the system in certain
embodiments.
[0050] In some embodiments and implementations, carbon dioxide may
be utilized to form carbonates of alkaline earth metals in one or
more of the hydrocavitation steps. This may render the resultant
alkaline metal carbonates as finely dispersed precipitates, which
may enhance the ease of subsequent mechanical filtration and may
further prevent or at least reduce scaling of one or more
components of an evaporative system through, for example, in-situ
sequestration of alkaline earth scalants.
[0051] Some embodiments may not only be configured to recycle water
or other treated fluids, but may also, or alternatively, be
configured to recycle heat energy. For example, some embodiments
may be configured to use waste heat from one or more
processes/systems to fuel an evaporative drying of purified sodium
chloride for production of useful products such as, for example,
road salt. Alternatively, or additionally, waste heat from one or
more processes/systems may be used to recover one or more other
potentially-valuable resources as a treatment byproduct such as,
for example, lithium salts. Such resources may be stored for later
reuse, used on-site, or a combination of the two. Examples of
methods and systems that may be used to recover lithium salts are
provided in U.S. Pat. No. 6,936,229 titled "Recovery of Lithium
Compounds from Brines," which is hereby incorporated by reference
in its entirety.
[0052] Some embodiments and implementations may further comprise
use of analytical systems and/or techniques to gather and/or
process data in an effort to optimize one or more process
conditions. In some such embodiments, the systems and/or techniques
may gather such data in real time. By so optimizing process
conditions some embodiments may allow for waste streams to be
efficiently partitioned for beneficial reuse. For example, in some
embodiments and implementations, the current density and/or the
retention time for one or more electrochemical processes may be
adjusted as needed in response to real-time parameters and/or
conditions. As another example, the amount of carbon dioxide used
during cavitation may be adjusted based upon one or more real-time
parameters and/or conditions. Similarly, in some embodiments and
implementations, the settling time for flotation/sedimentation may
be adjusted based upon one or more real-time parameters and/or
conditions. In other embodiments and implementations, one or more
of these parameters may instead be adjusted manually. Of course,
some embodiments may be configured to be selectively adjusted to
allow for automatic adjustment based upon real-time condition(s),
or to allow for manual adjustment when desired.
[0053] Such systems and/or techniques may, in some embodiments,
comprise use of a Laser Induced Breakdown Spectroscopy instrument
or system or another similar real-time detection module. Some such
embodiments may comprise use of a field portable Laser Induced
Breakdown Spectroscopy instrument or system. Alternatively, or
additionally, X-Ray Fluorescence (XRF) techniques may be applied to
assess real-time conditions.
[0054] Further details of certain examples of embodiments of
methods and systems according to the present disclosure will now be
provided in conjunction with the accompanying drawings. FIG. 1
depicts an example of a system 100 for treating a fluid, such as
wastewater. In some embodiments, system 100 may comprise a mobile
treatment system. As such, system 100, or at least one or more of
its constituent components, may be mounted or otherwise positioned
on, for example, a vehicle, trailer, or the like. System 100 may,
in such embodiments, thereby be brought to a particular site, such
as a fracking site, a drilling site, a refinery, or another site in
which wastewater is created and/or water is needed in, for example,
the oil and gas industries.
[0055] The wastewater from such a site may be routed through
treatment system 100 at, for example, waste feed port 102. As those
of ordinary skill in the art will appreciate, the wastewater
entering waste feed port 102 may include, for example, oil, soluble
organic compounds, suspended solids, silica, sodium ions, potassium
ions, lithium ions, chloride ions, iron ions, manganese ions,
magnesium ions, strontium ions, calcium ions, barium ions, radium
ions, and/or other transition metal ions and/or anionic and/or
cationic species.
[0056] In some embodiments, upon entering waste feed port 102, the
wastewater may be first routed through an electro-oxidation module
104. In some embodiments, electro-oxidation module 104 may be
configured to generate certain substances in-situ, such as sodium
hypochlorite. In some embodiments, certain substances, such as NaCl
from the waste stream, may be used in generating sodium
hypochlorite.
[0057] In some embodiments, as depicted in FIG. 1, prior to
entering electro-oxidation module 104, a Laser-Induced Breakdown
Spectroscopy (LIBS) module 140 may be used to analyze the
concentration of one or more wastewater components in the feed,
such as alkaline metals, alkaline earth metals, total carbon,
and/or iron, for example. Data gathered from LIBS module 140 may be
used to alter and/or disable one or more other modules in the
treatment system 100.
[0058] For example, in some embodiments, if the LIBS module 140
detects a concentration of carbon greater than a particular
threshold or a concentration of total alkaline earth metals (Ca,
Mg, Sr, and Ba, for example), or one or more such alkaline earth
metals, is less than another particular threshold, the
electro-oxidation module 104 may be bypassed by either disabling
electro-oxidation module 104 or diverting the stream around this
module. For example, in some embodiments, upon detecting a
concentration of carbon at a threshold of about 600 mg/L and/or
detecting a concentration of alkaline earth metals below about 50
mmol/L, the electro-oxidation module 104 may be bypassed by either
disabling electro-oxidation module 104 or diverting the stream
around this module.
[0059] In some embodiments, a threshold concentration or
concentrations may be associated with particular alkaline earth
metals. For example, in some embodiments, detecting a concentration
of calcium less than a particular threshold, such as about 1000
mg/L for example, may be used to determine whether to bypass
electro-oxidation. However, the electrocoagulation module 106 may
remain active and the wastewater stream may be fed therethrough.
However, if the carbon detected by the LIBS module 140 is below a
threshold and the alkaline earth metal concentration (or one or
more such alkaline earth metals) is above a threshold,
electro-oxidation may be performed in electro-oxidation module 104
and electrocoagulation may be bypassed by either disabling
electrocoagulation module 106 or diverting the stream around this
module. The operating parameter (e.g., the upper boundary of
treatment time) may be determined by using detected values of the
concentrations of major cation contaminants, such as Ca, Mg, and/or
Na obtained via LIBS in order to prevent undesired pH swings.
[0060] LIBS module 140 may comprise a unit that is physically
installed online as part of system 100. Alternatively, LIBS module
140 may comprise a handheld or otherwise portable device used by an
operator of system 100. In some embodiments, LIBS module 140 may be
incorporated into system 100 such that data generated from LIBS
module 140 may be automatically transmitted to other units in
system 100 and/or otherwise used by system 100 to alter one or more
functions, modules, and/or aspects of system 100. In alternative
embodiments, data generated from LIBS module 140 may be manually
input by a user into a computer system, which computer system may
be an integral part of treatment system 100, and may then be used
by system 100 to alter one or more functions, modules, and/or
aspects of system 100. As still another alternative, in some
embodiments, data generated from LIBS module 140 may be used to
manually alter one or more functions, modules, and/or aspects of
system 100. For example, a user may take a reading from LIBS module
140 and assess the need for one or more modules in system 100
and/or one or more parameters of one or more such modules and
manually disable, take off line, or otherwise adjust such module(s)
as needed in accordance with such data.
[0061] In some embodiments, one or more of the modules, such as
electro-oxidation module 104 and/or electrocoagulation module 106,
may be configured to increase the pH of the wastewater stream to
between about 11 and about 12. The wastewater stream may also be
sterilized by the electro-oxidation module 104. In addition, total
organic carbon may be reduced and/or Fe, Mn, Mg, and/or other heavy
metal ions may be precipitated at this stage in the system.
[0062] The stream may then be sent to an electrocoagulation module
106. Electrocoagulation module 106 may be configured to precipitate
silica and/or separate entrained organic material(s). In some
embodiments, electrocoagulation module 106 may be combined with
electro-oxidation module 104 in a single combined electrochemical
module. In other words, the functions associated with the
electro-oxidation module 104 and the electrocoagulation module 106
may be combined in a single unit if desired.
[0063] Once the stream exits electrocoagulation module 106 (or a
combined electrochemical module), the stream may then be sent to a
flotation/sedimentation module 108. Flotation/sedimentation module
108 may be configured to skim coagulated oil from the surface of
the fluid. In some embodiments, the sludge (containing, for
example, TSS, silica, microorganism cells, Fe, Mn, and/or
transition metal precipitates) may also be separated from the
aqueous phase within flotation/sedimentation module 108.
[0064] In some embodiments, electrocoagulation module 106 may be
combined with flotation/sedimentation module 108. For example, a
DAF ("Dissolved Air Flotation") unit may be combined with an EC
module by bubbling air or another gas through a perforated pipe,
disk, and/or plate, which may be located on the bottom of an EC
chamber in the EC/DAF module. The electrodes in the EC/DAF module
can be made up of for example, iron, steel, aluminum, and/or
stainless steel materials.
[0065] The geometry/arrangement of the electrodes in the EC/DAF
module may be of plate design, annulus design, or a combination of
the two. In embodiments in which plates are used, such plates may
be solid, perforated, or mesh. However, it has been discovered that
using aluminum as the EC electrode may obviate the DAF unit, in
which case rather than combining modules 106 and 108, such an
embodiment may simply remove or bypass module 108. Without being
limited by theory, it is thought that this may be true because the
gas bubbles formed on the surface of the aluminum electrode(s) may
provide the same, or at least a similar, function as would have
been provided by a DAF unit.
[0066] Electrocoagulation may be effective in the removal of silica
and transition metals, such as Fe and Mn. However, higher current
and/or longer treatment times may be needed in order to remove
alkaline earth metals. As discussed in greater detail below in the
Examples, by providing relatively high surface area per plate, a
greater number of parallel plates, and/or decreasing the distance
between the plates, the applied voltage necessary to achieve
desirable treatment results may be reduced, thereby decreasing
energy usage/requirements. In some embodiments, the polarity of
electrical current to the various plates may be alternating to
prevent scale build-up on the surface of the electrodes and also to
equalize electrode consumption.
[0067] Some embodiments may be configured to separate the incoming
stream to flotation/sedimentation module 108 into a plurality of
outgoing streams. For example, in the embodiment depicted in FIG.
1, the stream entering flotation/sedimentation module 108 is
separated into three separate outgoing streams. Namely, in the
depicted embodiment, an aqueous phase may be passed along to one or
more additional modules within treatment system 100. An oil phase
may be separated from flotation/sedimentation module 108, as shown
at 110. And a sludge phase may be separated from
flotation/sedimentation module 108, as shown at 112. Sludge phase
112 may contain, for example, TSS, microorganism cells, silica, Fe,
Mn, and/or other transition metal precipitates. In some
embodiments, sludge 112 may be passed along for further treatment.
Alternatively, sludge 112 may be directed to a tank or other
storage unit. In other embodiments, the stream entering
flotation/sedimentation module 108 may instead be separated into
just two separate outgoing streams, such as an aqueous stream and a
stream comprising oil, grease, and/or solids.
[0068] In the depicted embodiment, the aqueous phase is directed
into an evaporation and/or cavitation module 116. In some
embodiments, evaporation/cavitation module 116 may comprise an
energy-efficient, low-energy evaporation module.
[0069] In some embodiments, as depicted in FIG. 1, carbon dioxide
gas 114 may be introduced to evaporation module 116 in order to
facilitate precipitation of scale-forming elements (Ca, Mg, Ba, and
Sr, for example) within the aqueous phase. In some embodiments,
carbon dioxide may be added to the system by way of a tank or the
like. Alternatively, the carbon dioxide may be diverted from
exhaust gases produced from, for example, the combustion of
hydrocarbon fuels (e.g., diesel, natural gas, etc.), which may
further improve the impact to the environment by system 100 in such
embodiments. In some embodiments, carbon dioxide from such
combustion that is already taking place at one or more modules
within the system, or is otherwise already taking place at the
treatment site, may be utilized during this process. In this
manner, system 100 may not only avoid detrimental impact on the
environment, but may improve the environment by, for example,
reducing the carbon footprint of the system. Some embodiments may
be configured to use carbon dioxide from combustion when it is
available, and to use carbon dioxide from a tank when combustion
carbon dioxide is not currently available.
[0070] In some embodiments, cavitation may also be used to ensure
the precipitates maintain a suitable morphology for filtration and
do not precipitate out as scale on the equipment. In some
embodiments, such cavitation may be provided for within
evaporation/cavitation module 116. Some embodiments may comprise
use of ultrasound to generate cavitation within module 116 to
physically degrade large particulates in the stream. Some
embodiments may additionally, or alternatively, comprise use of
heat and/or highly-oxidizing conditions. Evaporation/cavitation
module 116 can be used in a single pass mode or, in some
embodiments, a recirculation mode. In other embodiments,
evaporation and cavitation may be provided in separate modules.
[0071] In some embodiments, a LIBS module 140 may be included in
the line prior to module 116 to guide the operation of cavitation
module 116. For example, in some embodiments, the amount of Ca
(data obtained via one or more LIBS modules) may influence the
retention time for CO.sub.2 cavitation treatment as well as the
pressure used during cavitation. Furthermore, in some embodiments,
pH adjustment may be guided based on the information of the
concentration of Ca and/or Mg.
[0072] In some embodiments, chemistry data collected by one or more
LIBS modules 140 may be fed back to fine tune module 116. For
example, if Na content is larger than about 20 mg/L, the
steam-to-liquid ratio may be changed (by decreasing operating
temperature and/or increasing pressure). Furthermore, the LIBS
analysis on the ultrafiltration permeate may be fed back to fine
tune the CO.sub.2 cavitation. For example, if the permeate contains
Ca over 15 mg/L, the retention time of CO.sub.2 treatment may need
to be increased.
[0073] In some embodiments, as depicted in the embodiment of FIG.
1, another LIBS module 140 may be included after module 116 to
ensure that treatment goals are being met. If such treatment goals
are not being met, system 100 may be configured to recirculate the
stream back through module 116 and/or one or more other modules.
For example, in some embodiments, system 100 may be configured to
set one or more treatment thresholds, such as a threshold of
cations (primarily Na, K, Ca, and Mg) of about 600 mg/L. If a LIBS
reading shows that the total concentration of cations is larger
than about 600 mg/L, system 100 may be configured to recirculate
the stream through the evaporation/cavitation module 116.
[0074] Steam generated from evaporation/cavitation module 116 may,
in some embodiments, be condensed, which may result in low-TDS
(Total Dissolved Solids) water that may be suitable for multiple
applications. In the depicted embodiment, steam from
evaporation/cavitation module 116 may be delivered to condenser
118. Water generated from condenser 118 may be delivered to a tank
128. Tank 128 may comprise a storage tank that may be used to store
the water for later use. Alternatively, tank 128 may comprise a
recycling tank that may be fed into one or more other
processes/systems on site. In some embodiments, tank 128 may serve
both purposes. In other words, tank 128 may be used to recycle
water and may also be used to store any excess water generated from
system 100. Water from tank 128 may be delivered out of system 100
at 130 if desired. As shown in FIG. 1, tank 128 may have a
plurality of outlets for delivery of water for other
systems/processes/purposes, including for use in processes involved
in system 100 and other processes/systems on site.
[0075] In some embodiments, as mentioned above, system 100 may be
configured to produce water that may be reused on site. Some
embodiments may be configured to treat wastewater sufficiently such
that it is potable once it reaches tank 128. In other embodiments,
such water may not be potable but may be sufficiently clean/treated
to be used in other systems/processes at a treatment site.
[0076] The resultant solution generated from evaporation/cavitation
module 116 may have a high-salt concentration. This resultant
solution may also contain precipitated carbonates and/or other
solids. This solution may then be passed through a crossflow
filtration module 120 (ultrafiltration, for example). Crossflow
filtration module 120 may comprise a crossflow ultrafiltration
module 120 in some embodiments. Crossflow filtration module 120
may, in some embodiments, comprise membranes made up of a ceramic,
sintered metal, and/or polymeric material. As mentioned above, in
other embodiments, other filtration modules and/or methods may be
used, such as sand or other media filtration.
[0077] Solid materials concentrated from crossflow filtration
module 120 may be delivered out of treatment system 100 at 122.
Such materials can be disposed of as waste, utilized in one or more
other processes within system 100 or otherwise at the site of
system 100, or can be stored in a tank or another such storage unit
at 122 for later use or disposal. Since the solid materials from
crossflow filtration module 120 may comprise a concentrated source
of Ca, Ba, and/or Sr chemicals, it may be desirable in some
embodiments to store and/or reuse such chemicals.
[0078] The permeate from crossflow filtration module 120, which may
comprise a concentrated NaCl solution, may be thermally processed
using a thermal processor 124. Some embodiments may be configured
to deliver water into storage tank 128 from both thermal processor
124 and condenser 118, as shown in FIG. 1. Thermal processor 124
may, in some embodiments, operate using waste heat generated from
elsewhere in system 100 to further reduce energy usage/demands. In
some embodiments, a solid product may be delivered from thermal
processor 124 at 126. In some embodiments, the solid product
delivered from thermal processor 124 may comprise NaCl. This
reclaimed NaCl may, in some embodiments, be stored for later use in
a wide variety of applications, such as winter road deicing, for
example. Depending on the source of wastewater, one or more other
high value resource elements, such as Li, may be reclaimed from the
wastewater, which may be subject to further processing in some
embodiments if economically viable. As shown in FIG. 1, additional
water may be reclaimed from thermal processor and directed to tank
128.
[0079] In some embodiments, module 120 may alternatively comprise,
or additionally comprise, a Reverse Osmosis (RO) module. This may
be useful to separate an incoming stream into outgoing streams
comprising one or more high-TDS streams and one or more low-TDS
streams. The high-TDS stream may be sent to an evaporator, such as
thermal processor 124, to produce one or more solid products, such
as a solid sodium chloride salt product, if desired.
[0080] In some embodiments, the Reverse Osmosis (RO) unit may be
configured to generate a low-TDS stream having less than about 100
mg/l TDS that may be suitable for multiple applications or reuse.
The high-TDS stream may be utilized in road deicing operations or
directed to an evaporation unit to develop a solid salt product.
The RO unit may be equipped with traditional polymeric or polymeric
composite membranes comprising one or more polymers and/or
additives such as graphene, graphene oxide, and/or carbon
nanotubes, for example, that may be configured to enhance the
membrane efficiency and/or lower treatment cost. Although wastes
with a TDS>about 50,000 mg/l may be unsuitable for treatment via
RO through currently known techniques, it is expected that this
number may increase as newer, higher efficiency membranes are
developed.
[0081] LIBS modules 140 may also, if desired, be included before
and/or after module 124, as previously discussed. For example, a
LIBS module 140 before module 124 may be used to provide a
chemistry profile of the NaCl solution from module 120 and such
data may be used to guide the operation of thermal processor 124.
For example, in some embodiments, the salt concentration obtained
by one or more LIBS modules before the stream enters module 124 may
be used to determine the steady state set point (temperature,
throughput, etc.) for the thermal process. The setting may get the
distillate to a quality close to a particular desired requirement
or threshold. Therefore, a LIBS module 140 downstream of module 124
may serve as a quality control check point.
[0082] Similarly, a LIBS module positioned in between modules 124
and 128 may be used to ensure that treatment goals are being met.
For example, in some embodiments, if a threshold of 20 mg/L of
total cations (primarily Na) is exceeded, either the steady-state
set point of module 124 may be adjusted or the stream may be
recirculated back through module 124.
[0083] FIG. 2 illustrates an example of a fluid treatment method
according to one implementation. As shown in this figure, method
200 may comprise receiving a fluid (wastewater, for example) stream
at step 202.
[0084] At step 204, a pH level of the fluid stream may be
increased. In some implementations, Fe, Mn, and/or other metals may
be precipitated or otherwise removed prior to step 204. In other
implementations, the pH increase obtained during step 204 may be
used to cause most of the Fe and/or other such metals to drop out
of the solution due to reaction with atmospheric and/or dissolved
oxygen. Step 204 may comprise, in some implementations, raising the
pH level of the fluid stream to between about 11 and about 12. As
also described above, this may be accomplished, in some
implementations, by using an electro-oxidation module. Such a
module may, in some implementations, also generate sodium
hypochlorite in-situ. In some implementations, the pH increase may
be obtained during step 204 by adding NaOH to the fluid stream. In
certain embodiments and/or implementations, a separate module may
be provided in order to increase or otherwise adjust the pH level
of the fluid stream.
[0085] At step 206, the fluid stream may be sterilized. Step 206
may be performed, for example, by one or more physical, chemical,
and/or electrochemical treatment methods. For example, in some
implementations, the fluid stream may be heated to a sufficient
temperature to destroy any, or at least most, harmful pathogens. In
other implementations, irradiation may be used to sterilize the
fluid stream, such as using gamma rays and/or ultraviolet
radiation, for example. Chemical methods may comprise, for example,
use of acids, alcohols, oxidizing chemicals, bactericides, or other
agents such as detergents and the like. In other implementations,
sterilization may be combined with one or more other steps. For
example, some implementations may comprise sufficient sterilization
during oxidation, which may occur during step 204 in some
implementations.
[0086] At step 208, the fluid stream may undergo an
electrocoagulation process. This may, in some implementations,
result in the precipitation of silica and/or separation of
entrained organic materials.
[0087] At step 210, coagulated oil resulting from step 208 may be
skimmed from the surface of the fluid stream. Step 212 may comprise
separating a sludge from the aqueous phase of the fluid stream. In
some implementations, steps 212 and 210 may take place
simultaneously, and may take place using a flotation/sedimentation
module.
[0088] Step 214 may comprise precipitating scale-forming elements,
such as calcium, barium, and strontium, for example. In some
implementations, radioactive radium may be precipitated during this
step to produce a concentrated solid. Such solids may be stored for
disposal at an appropriately licensed nuclear waste disposal site.
In some implementations, step 214 may be performed using carbon
dioxide gas. Such gas may, in some implementations, be introduced
from exhaust gases produced from, for example, the combustion of
hydrocarbon fuels (e.g., diesel, natural gas, etc.). In some
implementations, carbon dioxide from such combustion that is
already taking place at one or more modules within a system
configured to perform method 200 may be used. In other
implementations, carbon dioxide may be introduced from a tank or
the like. In some implementations, step 214 may comprise drawing
carbon dioxide from an on-site combustion process, or otherwise
from another on-site process/system and, if such carbon dioxide is
unavailable, drawing carbon dioxide from a backup tank or other
storage unit.
[0089] Step 216 may comprise running the aqueous phase through a
cavitation step in order to modify the morphology of the
precipitates to ensure that they do not precipitate out as scale on
equipment used in method 200. In some implementations, cavitation
bubbles may be generated and dispersed throughout the aqueous
phase. In some implementations, such bubbles may be introduced by
way of periodic oscillations or waves.
[0090] Step 218 may comprise heating the aqueous phase to generate
steam. In some implementations, this steam may be condensed and the
resultant water stored for later use.
[0091] Step 220 may comprise running the aqueous phase through a
crossflow filtration process in order to concentrate solids from
the aqueous phase. In some implementations, step 220 may comprise a
crossflow ultrafiltration process.
[0092] Step 222 may comprise processing and/or storage of a
permeate from step 220. For example, some implementations may
comprise thermally treating a concentrated NaCl solution resulting
from step 220 to generate a solid NaCl product. This product can be
stored for later use. As shown in FIG. 2, process 200 may be
repeated to continue processing wastewater and/or other fluid
streams. It should be understood that, in some implementations,
each of the various steps in process 200 may be taking place
simultaneously for various different portions of such an incoming
fluid stream.
[0093] Some implementations and embodiments of this invention can
be used to treat/handle a variety of waste products to generate low
TDS water suitable for either discharge to the environment or
reuse, with the benefit of the opportunity to recover resources for
beneficial reuse from the wastes. In some implementations and
embodiments, waste generation may be minimized, and chemical
consumption may be minimized. In some implementations and
embodiments, this may be accomplished by avoiding the need for
large chemical addition tanks, thereby reducing capital costs and
transportation fees.
[0094] Some embodiments and implementations may further comprise
use of real-time, in-line analytical monitoring techniques at one
or more steps/stages to optimize process efficiency and cost by
tailoring treatment requirements to clean up goals. This may be
achieved by application of emergent analytical techniques employing
emission spectroscopy. Some embodiments and implementations may
employ use of field-portable analytical equipment.
[0095] In some implementations, an atomic spectroscopy method, such
as Laser-induced spectroscopy or X-Ray Fluorescence (XRF) may be
employed. For example, by installing a Laser-Induced Breakdown
Spectroscopy (LIBS) prior to the electro-oxidation module,
information (such as salt concentration, for example) can be
collected in-line and in real-time, which can guide the adjustment
of flow rates, current density, and/or retention times to ensure
optimal performance. One or more such in-line analytical tools may
also be installed at one or more additional downstream sites. For
example, such tools may, in some embodiments and implementations,
be used in the stream of an ultrafiltration permeate or condensate
(after condenser 118 in the embodiment of FIG. 1) to determine
whether further treatment or recycling of the stream to a previous
treatment step or module is needed in order to meet desired reuse
criteria.
[0096] Various embodiments and implementations of the invention may
be further understood by the following Examples:
EXAMPLE 1
[0097] In a first working example, water from an oil fracking site
was treated in accordance with one embodiment of the invention.
This treatment process involved an electrocoagulation module, an
air flotation module, a carbon dioxide cavitation, and an
ultrafiltration module.
[0098] A DC supply (Sinometer HY3005D, 0-30V, 0-5A) was used as the
power source for the electrocoagulation testing. Parallel plating
of iron electrodes were used in the electrocoagulation module. The
current used in the electrocoagulation module was approximately 3.0
A, the associated voltage setting was approximately 4.0 V, and the
treatment was performed for eight minutes. Air flotation action was
simulated by bubbling air to the water through a porous stone/inlet
solvent filter. Filtration was achieved by pushing the water
through a 0.1 .mu.m syringe filter.
[0099] Table 1 below demonstrates various component levels both
before and after treatment of the wastewater in accordance with
this example.
TABLE-US-00001 TABLE 1 Na K Ca Mg Fe Ba Al Mn Sr (mg/l) (mg/l)
(mg/l) (mg/l) (mg/l) (mg/l) (mg/l) (mg/l) (mg/l) Before 6497.0 81.0
261.0 41.5 165.0 0.3 0.1 0.42 38.2 After 6457.0 74.0 2.2 0.2
UDL.sup.1 UDL UDL UDL 2.2 Cl Br NO.sub.3 + NO.sub.2 Silica IC.sup.2
TOC.sup.3 Oil/grease Bacteria Turbidity (mg/l) (mg/l) (mg/l) (mg/l)
(mg/l) (mg/l) (mg/l) (RLU) (NTU) Before 11387.0 45.0 0.4 36.1 151.0
819.4 8050.0 227.0 154.0 After 11244.0 33.4 -- UDL 61.9 574.0 1.0 0
0.4 .sup.1UDL: under detection limit .sup.2Inorganic carbon
.sup.3Total organic carbon
EXAMPLE 2
[0100] In a second working example, water from an oil fracking site
was treated repeatedly in accordance with another embodiment of the
invention. This treatment process involved an electrocoagulation
module, an air flotation module, and an ultrafiltration module.
Cavitation was not performed in the testing according to this
example. However, the current was varied in several iterations of
testing to determine the impact on treatment due to the current
used during electrocoagulation.
[0101] As with the testing of Example 1, a DC supply (Sinometer
HY3005D, 0-30V, 0-5A) was used as the power source for the
electrocoagulation testing, and parallel plates of iron electrodes
were used in the electrocoagulation module. Air flotation action
was again simulated by bubbling air to the water through a porous
stone/inlet solvent filter. Filtration was achieved by pushing the
water through a 0.1 .mu.m syringe filter. However, as mentioned
above, the current used in the electrocoagulation module was varied
in several iterations of testing while the treatment time remained
the same (six minutes).
[0102] Table 2 below demonstrates various component levels both
before and after treatment of the wastewater in accordance with
this example. As shown in the table, electrocoagulation has a
significant impact on removal of Fe, Mn, Si, bacteria, and
oil/grease, and regardless of the current intensity as long as the
current is above about 1 A. Higher current, however, tends to
result in better removal of alkaline earth metals (Mg, Ca, Sr, and
Ba). However, of course, more energy is needed in order to achieve
higher currents. Therefore, depending on the specific discharge
requirements and/or energy constraints, the current intensity may
be selected as desired in accordance with the results indicated in
the examples provided herein. For example, if it is required that
the Ca level be below 40 mg/L following electrocoagulation, 3 A may
be a proper selection of the current intensity. If the restriction
is only set for Si, heavy metals, bacteria and oil/grease, and/or
if another method is used for removal of alkaline earth metals, a
lower current intensity, such as about 1 A, may be preferable.
TABLE-US-00002 TABLE 2 Current Ca Mg Fe Mn Silica Ba Sr Bacteria
Oil/grease (A) (mg/l) (mg/l) (mg/l) (mg/l) (mg/l) (mg/l) (mg/l)
(RLU) (mg/l) Raw 261.00 41.50 165.00 0.42 36.10 0.30 38.20 227 8050
water 1 146.10 3.20 0.05 0.01 0.31 0.08 25.10 0 10.0 2 72.40 3.00
0.05 UDL UDL 0.03 17.30 0 UA.sup.1 3 33.10 UDL 0.02 0.02 0.03 UDL
13.70 0 3.0 4 5.40 UDL 0.02 UDL 0.06 UDL 11.30 0 5.6 .sup.1Data
unavailable
EXAMPLE 3
[0103] In a third working example, water from an oil fracking site
was treated repeatedly in accordance with yet another embodiment of
the invention. This treatment process involved an
electrocoagulation module, an air flotation module, and a
filtration module. Cavitation was not performed in the testing
according to this example. However, the treatment time associated
with electrocoagulation was varied in several iterations of testing
to determine the impact on treatment due to the electrocoagulation
treatment time while the applied current remained the same (3
A).
[0104] As with the testing of Examples 1 and 2, a DC supply
(Sinometer HY3005D, 0-30V, 0-5A) was used as the power source for
the electrocoagulation testing, and parallel plates of iron
electrodes were used in the electrocoagulation module. Air
flotation action was again simulated by bubbling air through the
water via a porous stone/inlet solvent filter. Filtration was
achieved by pushing the water through a 0.1 .mu.m syringe filter.
However, as mentioned above, the treatment time in the
electrocoagulation module varied in several iterations of
testing.
[0105] Table 3 below demonstrates various component levels both
before and after treatment of the wastewater in accordance with
this example. Within the range tested, the treatment time did not
substantially influence the removal of Fe, Mn, Si, bacteria and
oil/grease, because the removal of these components was already
significant after a two-minute treatment. As shown in the table,
longer treatment times tend to result in better removal of alkaline
earth metals. However, of course, there is a trade-off in terms of
efficiency associated with electrocoagulation treatment times,
since higher treatment times result in lower throughput and tend to
require more energy. Therefore, depending on the specific discharge
requirement, an appropriate treatment time should be selected. For
example, if 40 mg/L is set as the allowed discharge level for Ca as
a result of electrocoagulation, a treatment time of about eight
minutes may be desirable. If the restriction is only set for Si,
heavy metals, bacteria and oil/grease, and/or another method is
used for removal of alkaline earth metals, a lesser treatment time,
such as two minutes, may be sufficient.
TABLE-US-00003 TABLE 3 Time Ca Mg Fe Mn Si Ba Sr Bacteria
Oil/grease (min) (mg/l) (mg/l) (mg/l) (mg/l) (mg/l) (mg/l) (mg/l)
(RLU) (mg/l) Raw 261 41.50 165 0.42 36.10 0.30 38.20 227 8050 water
2 165.45 7.67 UDL 0.04 UDL 0.09 33.88 0 10.0 4 79.03 2.54 UDL 0.05
UDL 0.03 28.18 1 2.5 6 78.62 UDL UDL 0.06 UDL 0.06 24.45 0 4.0 8
20.56 UDL UDL 0.05 UDL 0.13 14.99 0 1.0
EXAMPLE 4
[0106] In a fourth working example, water from an oil fracking site
was treated repeatedly in accordance with still another embodiment
of the invention. This treatment process again involved an
electrocoagulation module, an air flotation module, and a
filtration module, but not a cavitation module. However, the metal
used for the electrodes in the electrocoagulation module was varied
in this example to determine the impact on treatment due to such
materials.
[0107] As with the testing of Examples 1-3, a DC supply (Sinometer
HY3005D, 0-30V, 0-5A) was used as the power source for the
electrocoagulation testing, and parallel plates of electrodes were
used in the electrocoagulation module. Air flotation action was
again simulated by bubbling air to the water through a porous
stone/inlet solvent filter. Filtration was again achieved by
pushing the water through a 0.1 .mu.m syringe filter. However, as
mentioned above, the electrodes in the electrocoagulation module
were varied during testing. More particularly, aluminum electrodes
were used in one test and iron electrodes were used in another
test.
[0108] Table 4 below demonstrates various component levels both
before and after treatment of the wastewater in accordance with
this example. As shown in the table, iron tends to provide better
removal of calcium and magnesium. If the wastewater is rich in
calcium or magnesium and/or if substantial Ca and/or Mg removal by
electrocoagulation is desired, use of an iron electrode may be
preferred.
TABLE-US-00004 TABLE 4 Ca Mg Fe Mn Si Ba Sr Electrode (mg/ (mg/
(mg/ (mg/ (mg/ (mg/ (mg/ material l) l) l) l) l) l) l) Raw 261 41.5
165 0.42 36.1 0.30 38.20 water Al 136.95 7.09 UDL 0.05 UDL 0.01
25.60 Fe 79.03 2.54 UDL 0.05 UDL 0.03 28.18
[0109] However, it has also been discovered that using aluminum as
the electrode material may obviate the need for a DAF unit. Without
being limited by theory, it is thought that this may be true
because the gas bubbles formed on the surface of the aluminum
electrode(s) may provide the same, or at least a similar, function
as would have been provided by a DAF unit. Aluminum electrodes may
be preferable for certain systems, such as systems treating
wastewater having a relatively low concentration of calcium (e.g.,
below about 200 mg/L), those having a strict limitation on the
footprint, and/or those lacking a DAF unit/module. Otherwise, iron
electrodes may be preferred since they are applicable to a wider
range of wastewater characteristics.
EXAMPLE 5
[0110] In a fifth working example, water from an oil fracking site
was treated repeatedly in accordance with another embodiment of the
invention. This treatment process again involved an
electrocoagulation module, an air flotation module, and a
filtration module, but not a cavitation module. However, the number
of electrodes (aluminum plate electrodes) in the electrocoagulation
module was varied in this example to determine the impact on
treatment due to varying the number of electrodes.
[0111] As with the testing of Examples 1-4, a DC supply (Sinometer
HY3005D, 0-30V, 0-5A) was used as the power source for the
electrocoagulation testing, and parallel plates of electrodes were
used in the electrocoagulation module. Air flotation action was
again simulated by bubbling air to the water through a porous
stone/inlet solvent filter. Filtration was again achieved by
pushing the water through a 0.1 .mu.m syringe filter. However, as
mentioned above, the number of plate electrodes used in the
electrocoagulation module varied during testing in accordance with
the data presented in Table 5.
[0112] Table 5 below demonstrates various component levels both
before and after treatment of the wastewater in accordance with
this example. As shown in the table, increasing the number of
electrodes tends to result in better removal of contaminants, even
using the same current. This suggests that energy consumption may
be reduced without sacrificing performance by increasing the number
of plates used in an electrocoagulation module.
TABLE-US-00005 TABLE 5 Ca Mg Fe Mn Si Ba Sr Plate Voltage (mg/ (mg/
(mg/ (mg/ (mg/ (mg/ (mg/ numbers (V).sup.a l) l) l) l) l) l) l) Raw
-- 261.0 41.5 165 0.4 36.1 0.3 38.2 water 6 plates 3.3 25.5 UDL UDL
0.02 UDL 0.1 23.1 4 plates 4.9 20.6 UDL UDL 0.05 UDL 0.1 15.0 2
plates 8.0 23.0 2.7 UDL 0.05 UDL 0.1 21.0 .sup.athe experiments
were controlled at the same current.
[0113] It is also thought that significant improvement in energy
consumption may be achieved, alone or in combination with a higher
number of electrode plates (preferably parallel electrode plates),
by providing a higher surface area per plate, and/or providing a
smaller distance between the plates. In some embodiments, the
polarity of the electrical current may be alternating to prevent
scale build-up on the surface of the electrodes and also to
equalize consumption rates between the electrodes. These results
further suggest that iron may be a better material choice for
electrodes than aluminum for many systems, due to its applicability
to treatment of wastewater having a wider range of characteristics.
A minimum electric charge (I't) of about 6 *minute may be desirable
for the removal of heavy metals, bacterial, silica, and/or
oil/grease. Higher electric charge may be needed for better removal
of alkaline earth metal contaminants by electrocoagulation.
EXAMPLE 6
[0114] In a sixth working example, water from a gas fracking well
site in the Marcellus Shale was treated in accordance with another
embodiment of the invention. This treatment process involved an
electrochemical module, pH adjustment, a cavitation module, and a
filtration module. More particular, in this example, the
electrochemical module comprised an electro-oxidation module. Due
to the wastewater characteristics, an electrocoagulation module was
omitted from this example. In addition, a flotation/sedimentation
module was also omitted from the example. Without being limited by
theory, it is thought that the gas bubbles formed on the surface of
the electrodes of the electrochemical module may serve one or more
of the same functions of the flotation/sedimentation module, such
as separating organic and light debris from the bulk liquid.
[0115] Electro-oxidation was achieved by conducting electric
current through mixed-metal oxide coated titanium plates immersed
under water. The electrodes used in this example comprised mesh
plates in parallel. However, other embodiments are contemplated in
which the plates may be solid or perforated, for example. In
addition, other embodiments are contemplated in which the geometric
arrangement of the electrodes could employ an annulus design.
[0116] Electro-oxidation was conducted under a 1 A electrical
current for 1 minute. However, it is anticipated that these
parameters may be highly dependent on the particular geometry and
other parameters of the system. For example, use of higher surface
area per plate, more plates, and/or shorter distances between the
plates may allow for significant reduction of applied voltage,
thereby providing significant improvement in energy
consumption.
[0117] Treatments in accordance with the principles of this example
can be performed in batch or continuous processes. In some
embodiments, high chloride (or bromide) concentrations may result
in production of free chlorine (or free bromine), which may be
useful in the oxidation of heavy metals, breakdown of organics,
and/or killing bacteria in the wastewater. In some embodiments, it
may therefore be useful to equip the electro-oxidation module with
a pH monitoring device and/or a free-chlorine analyzer, allowing
control flexibility to a wide range of wastewater and fine tuning
to variation of the feed water.
[0118] Table 6 below demonstrates various component levels both
before and after treatment of the wastewater in accordance with
this example.
TABLE-US-00006 TABLE 6 Na K Ca Mg Fe Ba Al Mn B (mg/l) (mg/l)
(mg/l) (mg/l) (mg/l) (mg/l) (mg/l) (mg/l) (mg/l) Before 125500.0
1170.0 14859.0 1512.0 3.7 51.6 0.0 1.1 24.6 After 125704.0 1207.0
0.8 UDL.sup.1 0.4 0.2 UDL UDL 39.7 Cl Br SO.sub.4 Silica TSS.sup.2
TN TOC.sup.3 Oil/grease Bacteria (mg/l) (mg/l) (mg/l) (mg/l) (mg/l)
(mg/l) (mg/l) (mg/l) (RLU) Before 127954.0 259.5 46.3 4.61 5755.5
229.6 29.9 1 75 After 123188.0 23.9 49.4 UDL 0 2.7 15.3 0 0
.sup.1UDL: under detection limit .sup.2Total suspended solid
.sup.3Total organic carbon
EXAMPLE 7
[0119] In a seventh working example, water from an gas fracking
well site in the Marcellus Shale was repeatedly treated in
accordance with another embodiment of the invention. This treatment
process again involved an electrochemical module comprising an
electro-oxidation module, pH adjustment, a cavitation module in all
but one iteration of this example, and an ultrafiltration module.
Electrocoagulation and flotation/sedimentation modules were again
omitted from this example. However, in this example, the pH
adjustments were varied in this example by adding NaOH to determine
the impact on treatment efficacy due to varying this parameter.
[0120] As with Example 6, electro-oxidation was achieved by
conducting electric current through mixed-metal oxide coated
titanium plates immersed under water. Electro-oxidation was again
conducted under a 1 A electrical current for 1 minute.
[0121] Table 7 below demonstrates various component levels both
before and after treatment of the wastewater in accordance with
this example. In one of the experimental iterations shown in Table
7, the result was obtained without use of a cavitation module as a
reference to show the effect of cavitation. Ca was removed
primarily via the mechanism of forming slightly soluble hydroxide.
In some embodiments, near complete removal of the contaminants may
not be achieved without a cavitation module. Otherwise, the pH
values in the chart were measured before the wastewater stream
entered the cavitation module. As shown in the table, increasing
the pH value of the wastewater stream prior to cavitation tends to
improve treatment efficacy. In addition, adjusting to higher pH
levels may improve the removal of alkaline earth metals. At lower
pH levels, for CO.sub.2 cavitation to be functional and effective,
a pH adjustment to at least about 11.5 may be desirable. Otherwise,
Ca may be primarily removed in the form of hydroxide. It is worth
mentioning that the pH of the effluent after the cavitation module
is about neutral. Thus, no acid addition is needed for certain
embodiments in the subsequent stages.
TABLE-US-00007 TABLE 7 Ca Mg Fe Mn Si Ba Sr (mg/ (mg/ (mg/ (mg/
(mg/ (mg/ (mg/ l) l) l) l) l) l) l) Raw 14859.0 1512.0 3.7 1.1 2.4
51.6 2921.0 pH = 8.sup.a 9628.0 UDL 0.3 0.1 UDL 51.5 2902.0 pH =
8.8.sup.a 6185.0 UDL 0.4 0.1 UDL 50.0 2701.0 pH = 9.7.sup.a 3542.0
UDL 0.4 0.1 UDL 50.4 2762.0 pH = 10.5.sup.a 975.0 UDL 0.4 0.1 UDL
38.8 2292.0 pH = 11.5.sup.a 0.8 UDL UDL UDL UDL 0.2 1.7 pH =
11.5.sup.b 109.0 0.19 0.05 UDL 0.1 47.2 2891.7 without CO.sub.2
.sup.athese pHs are the values that were measured before CO.sub.2
cavitation. .sup.bThe experiment result was obtained without
CO.sub.2 cavitation.
EXAMPLE 8
[0122] In an eighth working example, water from a fracking site was
treated in accordance with another embodiment of the invention.
This treatment process again involved an electrochemical module
comprising an electro-oxidation module, an electrocoagulation
module, an air flotation module, pH adjustment, a cavitation module
comprising a CO.sub.2 hydrocavitation module, and a crossflow
filtration module comprising an ultrafiltration module.
[0123] A DC supply (Sinometer HY3005D, 0-30V, 0-5A) was used as the
power source for the electro-oxidation and electro-coagulation
steps in this example. Electro-oxidation was achieved by conducting
electric current (1 A for 1 minute) using mixed-metal oxide coated
titanium plates immersed under water. Electro-coagulation was
achieved by conducting electric current (3 A for 6 minutes) using
iron plates. Air floatation action was simulated by bubbling air to
the liquid through a porous stone/inlet solvent filter. Filtration
was achieved by pushing the liquid through a 0.1 .mu.m syringe
filter.
[0124] Table 8 below demonstrates various component levels both
before and after treatment of the wastewater in accordance with
this example.
TABLE-US-00008 TABLE 8 Na K Ca Mg Fe Ba Cu (mg/l) (mg/l) (mg/l)
(mg/l) (mg/l) (mg/l) (mg/l) Before 100023.0 41.8 190.1 41.8 10.1
0.1 0.1 After 101250.5 37.0 UDL.sup.1 UDL UDL UDL UDL Mn Cl Br
Silica TN.sup.2 Oil/grease Bacteria (mg/l) (mg/l) (mg/l) (mg/l)
(mg/l) (mg/l) (RLU) Before 0.4 111323.0 53.6 36.1 21.0 7452.0 378
After UDL 110244.0 1.4 UDL UDL UDL 0 .sup.1UDL: under detection
limit .sup.2Total nitrogen
EXAMPLE 9
[0125] In a ninth working example, testing was performed to
simulate a potential embodiment of an evaporation module. More
particularly, this example should be considered an example of a
low-energy evaporation module. To obtain the results in the table
below, 400 ml of water was heated on a hot-plate with stirring. The
distillate was evaporated, condensed, and collected, and the
chemistry of the distillate was analyzed to assess the particulate
levels indicated in Table 9 below. This testing illustrates the
efficacy of an exemplary embodiment of an evaporation module, such
as module 116. However, other evaporation technologies, such as
mechanical vapor compression evaporators and thermal evaporators,
may alternatively, or additionally, be used for such a module.
[0126] Table 9 below demonstrates various component levels both
before and after treatment of the wastewater in accordance with
this example. The "before evaporation module" data represents
contaminants in a stream of fluid, such as wastewater, that may be
entering an evaporation module, such as evaporation module 116 in
the system of FIG. 1. The "distillate" data represents contaminants
in a distillate stream that may be exiting an evaporation module,
such as evaporation module 116 in FIG. 1. Thus, the "distillate"
data may represent, for example, a stream of fluid entering
condenser 118 in the system of FIG. 1. The "concentrate" data
represents contaminants in a concentrate stream that may be exiting
an evaporation module, such as evaporation module 116 in FIG. 1.
Thus, the "concentrate" data may represent, for example, a stream
of fluid entering filtration module 120 in the system of FIG.
1.
[0127] This result demonstrates the potential efficacy of a working
embodiment of a treatment system according to this invention, in
this case, such an embodiment comprising an electrocoagulation
module, an air flotation module, a CO.sub.2 cavitation module, an
ultrafiltration module, and a high-efficiency evaporator module.
The effluent ("clean" stream) contains only 15 mg/L Na, 0.2 mg/L K,
26.1 mg/L Cl and 0.1 mg/L Br (at least substantially free of
alkaline earth metals, heavy metals, silica, oil/grease and
bacteria). In some embodiments, the concentrated salt solution with
minimal impurity can be further concentrated and/or crystallized
for producing a deicing agent for local application in winter, or
can be accepted by another industrial partner for miscellaneous
uses.
TABLE-US-00009 TABLE 9 Na K Ca Mg Fe Ba Cu (mg/l) (mg/l) (mg/l)
(mg/l) (mg/l) (mg/l) (mg/l) Before evaporation 6460.0 74.0 2.2 UDL
UDL UDL UDL module Distillate (from 15.0 0.20 -- -- -- -- --
evaporation module) Concentrate (from 43000 540 14.6 -- -- -- --
evaporation module) Mn Cl Br Silica TN.sup.1 Oil/grease Bacteria
(mg/l) (mg/l) (mg/l) (mg/l) (mg/l) (mg/l) (BLU) Before evaporation
UDL 11200 33.4 UDL UDL UDL 0 module Distillate (from -- 26.1 0.10
UDL UDL UDL 0 evaporation module) Concentrate (from -- 74700 222 --
-- -- -- evaporation module) .sup.1Total nitrogen
[0128] Another example of a method 300 according to some
implementations is depicted in FIG. 3. At step 302, LIBS technology
or another technique/apparatus/system for gathering real-time data
to assess and/or alter a wastewater treatment system is applied to
a wastewater flow at one or more stages in the wastewater treatment
system. In some implementations, step 302 may comprise use of a
LIBS module, such as LIBS module 140 in system 100 of FIG. 1. In
some implementations, step 302 may comprise performing an analysis
of the wastewater stream as or before it enters a wastewater
treatment system. Because the LIBS analysis involved in step 302 is
performed before a particular treatment step and may be used to
alter such treatment step, as discussed below, step 302 should be
considered a pre-treatment LIBS analysis/step/module.
[0129] Data obtained from the analysis performed in step 302 may
then be used to determine, at step 304, whether modification of one
or more subsequent modules/steps in the treatment system are
needed. For example, in some embodiments, the calcium and magnesium
concentration in the incoming stream to system 100 detected by LIBS
may be used to determine whether electro-coagulation or
electro-oxidation would be in service. Also, such information may
be used in guiding whether pH adjustment is needed and how much
such adjustment is needed.
[0130] If data obtained from step 302 warrants a modification to
one or more subsequent treatment parameters, method 300 proceeds
from step 304 to step 306, at which point a modification may be
implemented with respect to one or more treatment modules,
parameters, and/or methods involved in the treatment system. For
example, in some embodiments, the concentration of calcium
monitored by one or more LIBS modules before an
evaporation/cavitation module may be used to influence how
cavitation would be operated in terms of CO.sub.2 pressure and/or
retention time. Also, or alternatively, such data may be used,
alone or in combination with the chemistry profile of the incoming
stream, as determined by a LIBS module, to assess whether and to
what extent pH adjustment may be needed at this stage. In some
implementations, step 302 may comprise disabling one or more
subsequent modules altogether or, alternatively, bypassing such
module(s).
[0131] If, at step 304, data obtained from step 302 indicates that
no modification to any modules/steps/parameters is needed, then
method 300 proceeds to step 308 from step 304. At step 308, the
wastewater stream may undergo a particular treatment, such as any
of the specific treatment modules referenced herein. Similarly, if
at step 304, data obtained from step 302 indicated that
modification to any modules/steps/parameters was needed, then
method 300 proceeds to step 308 from step 306 after such
modification(s) have been implemented.
[0132] Following the treatment involved in step 308, another LIBS
analysis may be performed at step 310. Again, like step 302, step
310 may comprise use of a LIBS module such as LIBS module 140.
However, because the LIBS analysis involved in step 310 is
performed after the treatment involved in step 308, and may be used
to repeat such treatment step, as discussed below, step 310 should
be considered a post-treatment LIBS analysis/step/module.
[0133] Step 310 may comprise assessing the wastewater after
undergoing the treatment involved in step 308 to ensure that it
meets certain treatment goals and/or thresholds. Data obtained from
step 310 may then be used to determine, in step 312, whether to
send the water through the treatment of step 308 again, as
indicated in FIG. 3, or not. In some implementations, if the
analysis of step 312 suggests the need for repeating a previous
treatment, the wastewater may be recirculated through an identical
treatment module. Alternatively, if the analysis of step 312
suggests the need for repeating a previous treatment, the
wastewater may be directed to another identical or similar
treatment module for further treatment.
[0134] To illustrate the principles of steps 310 and 312 with an
example, in some embodiments, the threshold of one or more heavy
metals (Fe, for example) may be set at 0.4 mg/L for the effluent
liquid stream after module 108 (referring back to FIG. 1). The
liquid with Fe exceeding the threshold may then be recirculated
back through an electrochemical treatment module. If the stream
following module 108 does not contain particulates exceeding the
threshold, the stream may be directed through the subsequent
modules without recirculation.
[0135] If the analysis of step 312 indicates that the treatment of
step 308 was sufficient and/or there is no need for further such
treatment, method 300 may proceed to step 314, at which point
another type of treatment may be performed. Again, the treatment of
step 314 may comprise use of any of the treatment modules
previously disclosed.
[0136] Still another example of a method 400 according to other
implementations is depicted in FIG. 4. At step 402, a wastewater
stream, such as a stream of frac water from a fracking site, enters
a water treatment system. Following step 402, method 400 may
proceed either to step 404 or to step 432. The process stemming
from step 404 comprises a more environmentally-friendly or benign
process, as discussed in greater detail below, relative to the
process stemming from step 432. Some water treatment systems
according to certain embodiments of the inventions may be
configured to selectively perform either the process stemming from
step 404 or the process stemming from step 432. Alternatively, such
systems may be configured to perform either the process stemming
from step 404 or the process stemming from step 432. In embodiments
configured to selectively perform either the process stemming from
step 404 or the process stemming from step 432, treatment may be
performed by way of the process stemming from step 432 in
circumstances where environmental concerns are not present, or are
less important.
[0137] Following the process stemming from step 404, a
determination may be made as to whether oil is present in the
wastewater at step 404. This determination may be made by, for
example, standard analytical techniques or visual inspection. In
some implementations, step 404 may comprise a predetermined
indication of whether oil is expected to be present that may be
made depending upon the site at which the process is implemented.
For example, processes implemented at a fracking site may be
configured such that step 404 automatically directs the process to
step 406 (discussed below), effectively disabling the portion of
method 400 beginning with step 408.
[0138] If the determination at step 404 indicates that no oil is
present in the water, the process proceeds to step 408, at which
point another determination is made as to whether levels of
particular chemicals and/or substances exceed a predetermined
threshold. In some implementations, step 408 comprises determining
whether Ca is present in an amount exceeding a threshold. In some
such implementations, this threshold may be about 1000 mg/L. One or
more of the determinations involved in step 408 may, in some
implementations, be made using Laser Induced Breakdown
Spectroscopy.
[0139] In some implementations, step 408 may further comprise
determining whether Mg is present in an amount exceeding a
threshold. In some such implementations, this threshold may be
about 500 mg/L.
[0140] In some implementations, step 408 may further comprise
determining whether the inorganic carbon in the water is greater
than a threshold percentage of the Ca content. For example, in some
implementations, step 408 may comprise determining whether the
inorganic carbon in the water is greater than about 60% of the Ca
content.
[0141] In certain preferred implementations, step 408 may comprise
making three separate determinations, as outlined above. For
example, in certain preferred implementations, step 408 may
comprise determining whether the Ca content is greater than about
1000 mg/L, whether the Mg content is greater than about 500 mg/L,
and whether the inorganic carbon is greater than about 60% of the
Ca content.
[0142] If one or more (in preferred implementations, each) of these
determinations meets the predetermined threshold, then the process
proceeds to step 420, at which still another determination is made
as to whether bacteria is present in the water. In some
implementations step 420 may comprise determining whether a
threshold amount of bacteria is present. In some implementations,
step 420 may comprise determining whether any detectable level of
bacteria is present. One or more such determinations may be made,
for example, using a method involving detection of adenosine
triphosphate (ATP) within the wastewater.
[0143] If, at step 420, it is determined that bacteria is present
and/or is exceeds a predetermined threshold, the process may
proceed to step 422 at which point one or more steps are taken to
kill and/or remove the bacteria. For example, in some
implementations, step 422 may comprise activating and/or directing
water through an electro-oxidation process. In some
implementations, the electro-oxidation process may be performed in
an electrochemical module, such as electrochemical module 104 of
FIG. 1.
[0144] Following step 422, the process may proceed to step 424, at
which point a pH adjustment may be made. In preferred
implementations, step 424 may comprise increasing the pH of the
water to between about 11 and about 12. If, at step 420, it is
determined that bacteria is not present and/or does not exceed a
predetermined threshold, the process may proceed directly from step
420 to step 424.
[0145] Following step 424, water may be directed to a
flotation/sedimentation module, such as module 108 in FIG. 1, at
step 426. In certain preferred implementations, a DAF ("Dissolved
Air Flotation") unit may be used in step 426.
[0146] Following step 426, water may be directed to an evaporation
module, such as module 116, at step 428, which may facilitate
precipitation of scale-forming elements. In some implementations,
step 428 may be performed using carbon dioxide gas. Such gas may,
in some implementations, be introduced from exhaust gases produced
from, for example, the combustion of hydrocarbon fuels (e.g.,
diesel, natural gas, etc.) already taking place at one or more
modules within a system configured to perform method 400 or
otherwise drawn from an on-site combustion process apart from such
a system.
[0147] The process may then proceed to step 430 for ultrafiltration
of the stream. In some implementations, step 430 may comprise
sending the stream through a crossflow filtration module, such as
crossflow filtration module 120 of FIG. 1.
[0148] Following step 430, the process may then proceed to step 442
at which point the stream of water may be directed out of the
treatment system. Preferably, at step 442, the water comprises a
solution of NaCl having Ca and Mg levels less than about 10 mg/L
without any detectable, or at least any significant, amounts of
bacteria, oil, or any heavy metals.
[0149] In some implementations, method 400 may terminate at step
442. However, in other implementations, the process may then
continue to step 444 for further processing by further
concentrating and/or crystallizing salt extracted from the stream.
In some implementations, step 444 may be performed at a different
site/system. In other implementations, the same system used to
perform the steps previously described may be used. Step 444 may,
in some implementations, be performed using a thermal processor,
such as module 124. The concentrated salt(s) may be compiled at 448
separate from the clean water stream at 446.
[0150] Returning to step 408 in method 400, if one or more of the
determinations of step 408 are under the predetermined
threshold(s), then the process proceeds to step 412, which may
comprise an electrocoagulation process. In some implementations,
step 412 may comprise actuating and/or directing the stream to an
electrocoagulation module, such as module 106.
[0151] Following the electrocoagulation treatment of step 412, the
process may then proceed through steps 414, 416, and 418. Steps
414, 416, and 418 may comprise steps similar or identical to steps
426, 428, and 430. In some implementations, these steps may
comprise, respectively, Dissolved Air Flotation treatment,
precipitation of scale-forming elements using carbon dioxide gas,
and ultrafiltration.
[0152] Returning to step 404, if oil is detected in the wastewater
stream (or if the process/system is configured to assume the
presence of oil), method 400 may proceed from step 404 to step 406,
at which point a determination is made as to whether levels of
particular chemicals and/or substances exceed a predetermined
threshold. In some implementations, step 406 comprises determining
whether Ca is present in an amount exceeding a threshold. In some
such implementations, this threshold may be about 1000 mg/L. One or
more of the determinations involved in step 406 may, in some
implementations, be made using Laser-Induced Breakdown
Spectroscopy.
[0153] In some implementations, step 406 may further comprise
determining whether Mg is present in an amount exceeding a
threshold. In some such implementations, this threshold may be
about 500 mg/L.
[0154] In some implementations, step 406 may further comprise
determining whether the inorganic carbon in the water is greater
than a threshold percentage of the Ca content. For example, in some
implementations, step 406 may comprise determining whether the
inorganic carbon in the water is greater than about 60% of the Ca
content.
[0155] In certain preferred implementations, step 406 may comprise
making three separate determinations, as previously described. For
example, in certain preferred implementations, step 406 may
comprise determining whether the Ca content is greater than about
1000 mg/L, whether the Mg content is greater than about 500 ppm or
mg/L, and/or whether the inorganic carbon is greater than about 60%
(molar percentage) of the total contents of alkaline earth
metals.
[0156] If one or more (in preferred implementations, each) of these
determinations meets the predetermined threshold, then the process
proceeds to step 410 at which point a pH adjustment is made. As
with step 424, step 410 may, in certain preferred implementations,
comprise adjusting the pH level to between about 11 and about
12.
[0157] If one or more of the determinations of step 406 are under
the predetermined threshold(s), then the process proceeds to step
412 from step 406. Step 412, as previously mentioned, may comprise
an electrocoagulation process. Following step 412, the process may
then proceed through steps 414, 416, 418, 442, and 444, as
previously described.
[0158] As an alternative to the process stemming from step 404,
method 400 may instead proceed from 402 to step 432, as shown in
FIG. 4. In step 432, a carbonate salt, such as calcium carbonate
may be added to the wastewater to facilitate further processing of
the water, such as precipitation of heavy metals for example.
[0159] Following step 432, the water stream may be subjected to a
hydrocyclone or a settling process at step 434, which may be used
to separate certain types of fluids and/or other substances, such
as oil, from the water. The process may then proceed to step 436,
which may comprise an electrocoagulation process, as described
above in connection with step 412.
[0160] Step 438 may comprise directing the stream into and/or
through a flotation/sedimentation module, such as module 108 in
FIG. 1. In certain preferred implementations, a DAF ("Dissolved Air
Flotation") unit may be used in step 438. Following step 438, the
water may undergo ultrafiltration, such as crossflow
ultrafiltration module, at step 440. The process may then proceed
to step 442, which is described above.
[0161] It will be understood by those having skill in the art that
changes may be made to the details of the above-described
embodiments without departing from the underlying principles
presented herein. For example, any suitable combination of various
embodiments, or the features thereof, is contemplated.
[0162] Throughout this specification, any reference to "one
embodiment/implementation," "an embodiment/implementation," or "the
embodiment/implementation" means that a particular feature,
structure, or characteristic described in connection with that
embodiment/implementation is included in at least one
embodiment/implementation. Thus, the quoted phrases, or variations
thereof, as recited throughout this specification are not
necessarily all referring to the same
embodiment/implementation.
[0163] Similarly, it should be appreciated that in the above
description of embodiments, various features are sometimes grouped
together in a single embodiment, figure, or description thereof for
the purpose of streamlining the disclosure. This method of
disclosure, however, is not to be interpreted as reflecting an
intention that any claim require more features than those expressly
recited in that claim. Rather, inventive aspects lie in a
combination of fewer than all features of any single foregoing
disclosed embodiment or implementation. Accordingly, this
disclosure is to be regarded in an illustrative rather than a
restrictive sense, and all such modifications are intended to be
included within the scope thereof.
[0164] Likewise, benefits, other advantages, and solutions to
problems have been described above with regard to various
embodiments. However, benefits, advantages, solutions to problems,
and any element(s) that may cause any benefit, advantage, or
solution to occur or become more pronounced are not to be construed
as a critical, a required, or an essential feature or element.
[0165] It should be further understood that the method steps and/or
actions described herein may be interchanged with one another. In
other words, unless a specific order of steps or actions is
explicitly required for proper operation of the embodiment, the
order and/or use of specific steps and/or actions may be modified.
In addition, it should be understood that other implementations of
such methods need not necessarily include each of the recited
steps, and further that certain steps from certain implementations
disclosed herein may be interchanged with other implementations, as
those of ordinary skill in the art would appreciate.
[0166] It will be apparent to those having skill in the art that
changes may be made to the details of the above-described
embodiments without departing from the underlying principles set
forth herein. The scope of the present invention should, therefore,
be determined only by the following claims.
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