U.S. patent application number 11/239797 was filed with the patent office on 2006-09-07 for biodestruction of blended residual oxidants.
Invention is credited to Jess C. Brown, Edwin J. JR. Hansen, Brandon C. Heidelberger, Rick D. Wheadon.
Application Number | 20060196828 11/239797 |
Document ID | / |
Family ID | 36953850 |
Filed Date | 2006-09-07 |
United States Patent
Application |
20060196828 |
Kind Code |
A1 |
Brown; Jess C. ; et
al. |
September 7, 2006 |
Biodestruction of blended residual oxidants
Abstract
The oxidant waste stream treatment may provide for treatment of
oxidant laden waste streams. A screened or clarified wastewater
stream may be combined with an oxidant stream to produce a blended
stream. The blended stream may be processed in a bioreactor.
Inventors: |
Brown; Jess C.; (Sarasota,
FL) ; Heidelberger; Brandon C.; (Sandy, UT) ;
Wheadon; Rick D.; (Alpine, UT) ; Hansen; Edwin J.
JR.; (Magna, UT) |
Correspondence
Address: |
DENNIS W. BEECH (LAW OFFICE OF DENNIS W. BEECH)
P.O. BOX 519
MURRIETA
CA
92564-0519
US
|
Family ID: |
36953850 |
Appl. No.: |
11/239797 |
Filed: |
September 28, 2005 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11070923 |
Mar 3, 2005 |
|
|
|
11239797 |
Sep 28, 2005 |
|
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Current U.S.
Class: |
210/620 |
Current CPC
Class: |
C02F 1/70 20130101; Y02W
10/10 20150501; C02F 3/02 20130101; Y02W 10/15 20150501; C02F 3/06
20130101; C02F 3/025 20130101 |
Class at
Publication: |
210/620 |
International
Class: |
C02F 3/02 20060101
C02F003/02 |
Claims
1. A method for treatment of oxidant laden waste streams
comprising: combining a wastewater stream with an oxidant stream
having oxy-anions at a ratio of between 20% volumetric flow rate
and 75% volumetric flow rate to produce a blended stream; and
processing said blended stream in a bioreactor.
2. The method as in claim 1 wherein said ratio for combining is the
flow rate of said oxidant stream divided by the sum of the flow
rate of said oxidant stream and the flow rate of said municipal
wastewater stream.
3. The method as in claim 1 wherein said blended stream having
lower concentrations of dissolved oxygen and total dissolved
solids, and a higher concentration of a biodegradable organic
matter than said oxidant stream.
4. The method as in claim 1 wherein said blended stream having a pH
between approximately 5 and 10.
5. The method as in claim 1 wherein the temperature of said blended
stream is between approximately 5 degrees and 40 degrees
Celsius.
6. The method as in claim 1 wherein the empty bed contact time in
said bioreactor is between approximately 3 minutes and 120
minutes.
7. The method as in claim 1 wherein said wastewater stream is a
portion of a wastewater stream source at a wastewater treatment
facility.
8. The method as in claim 1 wherein said wastewater stream is a
portion of a wastewater stream source channeled to an oxidant
stream source site.
9. The method as in claim 1 wherein said wastewater stream is
processed for the removal of suspended solids prior to being
combined with said oxidant stream.
10. The method as in claim 1 wherein said bioreactor is selected
from the group consisting of a suspended growth reactor and a fixed
film reactor.
11. (canceled)
12. The method as in claim 1 wherein said wastewater stream having
an organic content that serves as an electron donor source to
reduce the oxidants present in said oxidant stream.
13. The method as in claim 12 wherein said wastewater stream having
a lower concentration of dissolved oxygen than said oxidant
stream.
14. The method as in claim 12 wherein said wastewater stream having
a lower concentration of total dissolved solids than said oxidant
stream.
15. The method as in claim 12 wherein said wastewater stream having
a perchlorate-reducing bacteria to seed said bioreactor.
Description
[0001] This is a continuation-in-part of U.S. patent application
Ser. No. 11/070,923 Filed on Mar. 3, 2005. U.S. patent application
Ser. No. 10/070,923 is pending.
BACKGROUND OF THE INVENTION
[0002] This invention relates to processes for treatment of
concentrated oxidant waste streams. The new method may combine a
wastewater stream with an oxidant laden stream to produce a blended
stream that may be treated in a bioreactor.
[0003] Existing processes used to biologically treat concentrated
oxidant streams may typically require a dedicated deoxygenating
step, require long residence times due to high solution salinities,
require the addition of an exogenous substrate such as ethanol, or
require inoculation with exogenous salt tolerant bacteria. As an
example, nitrate and perchlorate may be removed in a drinking water
treatment process. If a brine line discharge may not exist or be
permitted, the waste streams may often be treated using a dedicated
brine bioreactor designed to degrade nitrate and perchlorate in a
waste stream. There may be several problems associated with
biologically treating saline waste streams. Microbial cultures may
be very sensitive to slight changes in ionic strength, that is,
total dissolved solids. Increased salinity may tend to disrupt
normal metabolic function and thereby reduce degradation kinetics.
Treating saline wastewaters can increase the concentration of
effluent solids. Acclimating effective salt tolerant cultures using
traditional microbial sources, for example, sludge from a municipal
wastewater treatment plant, may be difficult.
[0004] Other considerations for dedicated brine bioreactors may be
that the waste stream must be anoxic/anaerobic to achieve
biological oxidant reduction. Also, an exogenous electron donor
such as acetic acid or ethanol must be added to the system to serve
as a substrate, an electron donor.
SUMMARY OF THE INVENTION
[0005] The present invention is directed to methods and processes
for treatment of oxidant laden waste streams. A wastewater stream
may be combined with an oxidant stream to produce a blended stream.
The blended stream may be processed in a bioreactor.
[0006] These and other features, aspects and advantages of the
present invention will become better understood with reference to
the following drawings, description and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 illustrates a flow diagram of the process according
to an embodiment of the invention;
[0008] FIG. 2 illustrates a flow diagram of the process according
to an embodiment of the invention.
DETAILED DESCRIPTION
[0009] The following detailed description represents the best
currently contemplated modes for carrying out the invention. The
description is not to be taken in a limiting sense, but is made
merely for the purpose of illustrating the general principles of
the invention.
[0010] Referring to FIGS. 1 and 2, a method for treatment of
oxidant laden waste, for example, nitrate, perchlorate, bromate and
the like, residual streams may combine a processed, for example,
screened or clarified wastewater stream 20 with an oxidant stream
14 to produce a blended stream. The blended stream 16 may be
treated in a bioreactor 12 that reduces the oxidants to innocuous
by-products. The bioreactor 12 may be a suspended growth reactor, a
granular media fixed film reactor, a membrane based fixed film
reactor or the like. The bioreactor effluent 22 and waste biomass
18 may be discharged to a sewer or other collection system.
[0011] The use of municipal wastewater 20 may decrease the bulk
dissolved oxygen concentration. This may decrease the contact time
required to achieve biological oxidant reduction since dissolved
oxygen may competitively inhibit biological nitrate, perchlorate
and bromate reduction. Blending the oxidant concentrated waste
stream 14 with municipal wastewater 20 may typically decrease the
salinity and thereby may improve biodegradation kinetics. The
background organics present in municipal wastewater 20 may serve as
the substrate for biological oxidant reduction such that no
exogenous substrate may need to be added to the system, which may
reduce costs and concerns associated with chemical amendments. The
bioreactor 12 may be acclimated with organisms indigenous to the
local wastewater thereby eliminating the need for an exogenous
microbial enrichment or seed.
[0012] The wastewater should contain organics that may serve as an
electron donor to reduce oxidants present in the oxidant stream.
The wastewater stream may contain lower concentrations of dissolved
oxygen than the oxidant stream such that the dissolved oxygen
concentration in the blended stream may be lower than the dissolved
oxygen concentration in the oxidant stream. The wastewater stream
may also contain lower concentrations of total dissolved solids,
that is, salinity, than the oxidant stream such that the total
dissolved solids concentration in the blended stream may be lower
than the total dissolved solids concentration in the oxidant
stream. The wastewater stream may contain perchlorate reducing
bacteria that may seed the biological reactor.
[0013] The treatment process or method may combine screened or
clarified wastewater 20 scalped from a local wastewater system with
a concentrated oxidant stream 14 at the site where the oxidant
stream 14 may be generated, for example, a drinking water treatment
plant, a chemical plant such as for solid rocket fuel
manufacturing, or the like, and then treat the blended stream 16 in
a dedicated bioreactor 12. The concentrated oxidant stream 14 may
be collected and transported to a municipal wastewater treatment
facility where it may be combined with a side stream of screened or
clarified wastewater and treated in a dedicated bioreactor 12.
[0014] Blending of the oxidant stream 14 and screened or clarified
municipal wastewater stream may occur at a wide range of ratios
that may be site specific. Ambient wastewater quality may be used
as a wide range of acceptable water quality may be anticipated.
[0015] The oxidant stream 14 may be combined with a municipal
wastewater stream at a ratio of 20% to 75% to produce a blended
stream 16. The combining ratio relationship is defined as the flow
rate of the oxidant stream divided by the sum of the flow rate of
the oxidant stream and the flow rate of the municipal wastewater
stream. The blended stream 16 may contain lower concentrations of
dissolved oxygen and total dissolved solids, and a higher
concentration of biodegradable organic matter than the oxidant
stream 14.
[0016] Of the bioreactors 12 available, the fixed film bioreactor
for perchlorate reducing metabolic activity may be more stable than
that of suspended cultures. Research may have shown that when
suspended perchlorate reducing bacteria are exposed to dissolved
oxygen their perchlorate reducing metabolic activity may recover
slowly when anaerobic conditions are reestablished. Perchlorate
degradation kinetics in fixed film processes may not be
significantly impacted by transient dissolved oxygen exposure. A
gradient of redox potential may develop across the depth of a
reactor bed. This may allow for the development of semidistinct
dissolved oxygen, nitrate and perchlorate reducing zones in the bed
that may force bacteria to utilize a specific metabolic activity
instead of continuously altering metabolic states. A redox
potential gradient may be established across the depth of a given
biofilm that may permit perchlorate reduction even if the bulk
solution may not be fully anaerobic.
[0017] Experiments have shown that destruction of perchlorate
concentrates to below detection may be achieved through wastewater
blending and treatment in a fixed bed bioreactor. The results show
that no amendments may be necessary other than wastewater and that
required empty bed contact times may be approximately 10 minutes or
less. The blended stream 16 may have a pH between 5 and 9;
although, higher or lower pH levels may be used, it has been found
that additional chemical components may need to be added for
treatment of the blended stream. Such chemical treatment may make
the process less efficient, particularly concerning the overall
cost of the process. The temperature of the blended stream may be
maintained between approximately 5 and 30 degrees Celsius. The
empty bed contact time may vary between approximately 3 and 60
minutes.
[0018] While the invention has been particularly shown and
described with respect to the illustrated embodiments thereof, it
will be understood by those skilled in the art that the foregoing
and other changes in form and details may be made therein without
departing from the spirit and scope of the invention.
* * * * *