U.S. patent application number 13/470971 was filed with the patent office on 2012-09-06 for methods, apparatus and systems for polishing wastewater utilizing natural media filtration.
This patent application is currently assigned to CORPORATE ENVIRONMENTAL SOLUTIONS LLC. Invention is credited to Aniruddha Bhattacharyya, Jaw Fu, Dennis L. Fulmer, Rajat Ghosh, Robert C. Horger, Jonell Kerkhoff, Kevin Kitzman, Andrew C. Middleton, John R. Smith, Robin L. Weightman.
Application Number | 20120223029 13/470971 |
Document ID | / |
Family ID | 38235276 |
Filed Date | 2012-09-06 |
United States Patent
Application |
20120223029 |
Kind Code |
A1 |
Smith; John R. ; et
al. |
September 6, 2012 |
METHODS, APPARATUS AND SYSTEMS FOR POLISHING WASTEWATER UTILIZING
NATURAL MEDIA FILTRATION
Abstract
Wastewater treatment systems, methods and apparatus for
polishing a wastewater stream comprising a plurality of
contaminants are provided. One system includes a vessel containing
a plurality of natural media filtration agents selected to remove
selected ones of the plurality of contaminants from the wastewater
stream. In one embodiment, the vessel includes a bed of bauxite
residue and at least one other natural media filtration agent. In
another embodiment, the vessel includes a bed of compost and at
least one other natural media filtration agent. The vessel includes
a wastewater inlet that is in fluid communication with one or more
of the natural media filtration agents. The vessel includes a
wastewater outlet that is in fluid communication with one or more
of the natural media filtration agents.
Inventors: |
Smith; John R.; (Pittsburgh,
PA) ; Fu; Jaw; (Murrysville, PA) ; Ghosh;
Rajat; (Pittsburgh, PA) ; Kitzman; Kevin;
(Wanatchee, WA) ; Kerkhoff; Jonell; (Murrysville,
PA) ; Horger; Robert C.; (New Kensington, PA)
; Fulmer; Dennis L.; (Greensburg, PA) ;
Bhattacharyya; Aniruddha; (Fairfax Station, VA) ;
Middleton; Andrew C.; (Mount Sidney, VA) ; Weightman;
Robin L.; (Murrysville, PA) |
Assignee: |
CORPORATE ENVIRONMENTAL SOLUTIONS
LLC
Bridgeville
PA
ALCOA INC.
Pittsburgh
PA
|
Family ID: |
38235276 |
Appl. No.: |
13/470971 |
Filed: |
May 14, 2012 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11672762 |
Feb 8, 2007 |
8206586 |
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13470971 |
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60772308 |
Feb 9, 2006 |
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Current U.S.
Class: |
210/807 ;
210/263; 210/290 |
Current CPC
Class: |
C02F 2101/18 20130101;
C02F 1/281 20130101; C02F 2101/103 20130101; C02F 2101/20 20130101;
C02F 2101/14 20130101; C02F 1/001 20130101; C02F 1/283 20130101;
C02F 1/288 20130101; C02F 1/705 20130101; C02F 1/004 20130101; C02F
2101/327 20130101; C02F 2101/22 20130101; C02F 1/286 20130101; C02F
1/28 20130101 |
Class at
Publication: |
210/807 ;
210/263; 210/290 |
International
Class: |
C02F 1/00 20060101
C02F001/00; B01D 24/00 20060101 B01D024/00 |
Claims
1. A wastewater treatment system comprising a single bed for
polishing a wastewater stream comprising a plurality of
contaminants, the treatment system comprising: a vessel comprising
a bed of compost and at least one other natural media filtration
agent; a wastewater inlet in fluid communication with at least one
of the compost material and the at least one other natural media
filtration agent; and a wastewater outlet in fluid communication
with at least one of the compost material and the at least one
other natural media filtration agent.
2. The wastewater treatment system of claim 1, wherein the vessel
is one of an in-ground pit, an above-ground tank and a combination
thereof.
3. The wastewater treatment system of claim 1, wherein the at least
one other natural media filtration agent is one or more of bauxite
residue, iron filings, granular activated carbon, and bone
char.
4. The wastewater treatment system of claim 1, wherein the at least
one other natural media filtration agent is two or more of bauxite
residue, iron filings, granular activated carbon, and bone
char.
5. The wastewater treatment system of claim 1, wherein the at least
one other natural media filtration agent is three or more of
bauxite residue, iron filings, granular activated carbon, and bone
char.
6. The wastewater treatment system of claim 1, wherein the at least
one other natural media filtration agent is all of bauxite residue,
iron filings, granular activated carbon, and bone char.
7. The wastewater treatment system of claim 1, wherein the compost
and the at least one other natural media filtration agent are
commingled within the vessel.
8. The wastewater treatment system of claim 1, wherein the vessel
comprises a first filtration layer and a second filtration layer,
wherein the second :filtration layer is separate from the first
filtration layer, and wherein the first filtration layer comprises
the compost and wherein the second filtration layer comprises the
at least one other natural media filtration agent.
9. A wastewater treatment system comprising a single bed for
polishing a wastewater stream comprising a plurality of
contaminants, the treatment system comprising: a vessel comprising
a bed of aggregate and bauxite residue; a wastewater inlet of the
vessel in fluid communication with at least one of the aggregate
and the bauxite residue; and a wastewater outlet of the vessel in
fluid communication with at least one of the aggregate and the
bauxite residue.
10. The wastewater treatment system of claim 9, wherein the
aggregate and bauxite residue are commingled within the vessel.
11. The wastewater treatment system of claim 9, wherein the bed
comprises a first filtration layer contained within the vessel and
a second filtration layer contained within the vessel, wherein the
second filtration layer is separate from the first filtration
layer, and wherein the first filtration layer comprises the bauxite
residue and wherein the second filtration layer comprises the
aggregate.
12. The wastewater treatment system of claim 9, wherein the vessel
further comprises at least one other natural media filtration agent
selected from the group consisting of compost, granular activated
carbon, iron filings and bone char.
13. A method for producing a wastewater polishing bed adapted to
polish wastewater comprising a plurality of contaminants, the
method comprising: determining a wastewater stream profile for a
wastewater stream that comprises a plurality of contaminants, the
wastewater stream profile comprising a wastewater contaminant
profile and at least one of a wastewater flow profile and a
wastewater effluent goal; selecting a plurality of natural media
filtration agents for use in the wastewater polishing bed, wherein
the selecting step is based at least in part on the wastewater
contaminant profile, wherein a first one of the plurality of
natural media filtration agents is bauxite residue and wherein a
second one of the plurality of natural media filtration agents is
one of compost, granular activated carbon, iron filings, bone char
and aggregate; selecting a single bed configuration based in part
on the first and second natural media filtration agents, and
further based at in part on at least one of the wastewater flow
profile and the wastewater effluent goal; and producing a single
treatment bed comprising the plurality of natural media filtration
agents based at least in part on the single bed configuration.
14. The method of claim 13, wherein the wastewater contaminant
profile indicates the presence of one at least one of aluminum,
chlorine, atrazine, and bioaccumulative organics, and wherein the
second one of the plurality of natural media filtration agents is
compost.
15. The method of claim 13, wherein the wastewater contaminant
profile indicates the presence of at least one of arsenic, cyanide,
chromium, pathogens, and selenium, and wherein the second one of
the plurality of natural media filtration agents is iron
filings.
16. The method of claim 13, wherein the wastewater contaminant
profile indicates the presence of at least one of chlorine,
polychlorinated biphenyls, and polynuclear aromatic hydrocarbons,
and wherein the second one of the plurality of natural media
filtration agents is granular activated carbon.
17. The method of claim 13, wherein the wastewater contaminant
profile indicates the presence of at least one of arsenic, fluoride
and lead, and wherein the second one of the plurality of natural
media filtration agents is bone char.
18. The method of claim 13, wherein the selecting a plurality of
natural media filtration agents step comprises selecting at least
three natural media filtration agents for use in the wastewater
polishing bed, wherein the first one of the plurality of natural
media filtration agents is bauxite residue, wherein the second one
of the plurality of natural media filtration agents is aggregate,
and wherein a third one of the plurality of natural media
filtration agents is one of compost, granular activated carbon,
iron filings and bone char.
19. The method of claim 13, further comprising: flowing the
wastewater stream through the single treatment bed comprising the
first and second natural media filtration agents; removing at least
a portion of a first contaminant of the wastewater stream via the
first one of the natural media filtration agents; and removing at
least a portion of a second contaminant of the wastewater stream
via the second one of the natural media filtration agents.
20. The method of claim 19, further comprising: discharging, after
the flowing step, a discharge water stream from the single
treatment bed, wherein the discharge water stream comprises not
greater than legally allowed limits of the first and second
contaminants.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S)
[0001] This patent application claims priority to U.S. Provisional
Patent Application No. 60/772,308 filed Feb. 9, 2006, entitled
"ENHANCED NATURAL MEDIA FILTRATION (NMF) WATER TREATMENT
TECHNOLOGY", and is related to PCT Application No. PCT/US07/61821
filed Feb. 8, 2007, entitled "METHODS, APPARATUS AND SYSTEMS FOR
POLISHING WASTEWATER UTILIZING NATURAL MEDIA FILTRATION", each of
which is incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to methods, systems and
apparatus for polishing wastewater (i.e., non-potable water) using
natural filtration media, such as compost, bauxite residue, and/or
iron filings, to name a few.
BACKGROUND OF THE INVENTION
[0003] Prior to discharge to the environment, wastewater must
generally contain not greater than trace levels of various
contaminants. To properly discharge treated water, a polishing step
may be employed. Wastewater polishing generally comprises removing
trace impurities from the wastewater stream prior to discharge.
Conventional wastewater polishing approaches include disinfection
(e.g., via chlorination/de-chlorination, UV and/or ozone) and
membrane treatment, to name two. Disinfection via
chlorination/de-chlorination is costly from both a
consumables/labor perspective and a capital cost perspective.
Furthermore, such disinfection methods are inefficient in that the
chlorine must be both added to and removed from the water stream.
Additionally, since chlorine gas is hazardous, it must be stored in
large gas tanks, which are not only subject to stringent
regulations, but are also possible terrorism targets. Similar
issues arise with respect to UV, ozone and membrane treatment
technologies. Consequently, there exists a need for better methods,
systems and apparatus for wastewater polishing.
SUMMARY OF THE INVENTION
[0004] In view of the foregoing, a broad objective of the present
invention is to provide more effective wastewater polishing
methods, systems and apparatus.
[0005] Another objective is to decrease the amount of systems, and
hence capital costs, associated with wastewater polishing.
[0006] A further objective is to increase the amount of
environmentally friendly wastewater treatment materials and
decrease the amount of hazardous or non-environmentally friendly
wastewater treatment materials utilized in wastewater
polishing.
[0007] Another objective is to decrease the amount of maintenance
associated with wastewater polishing systems.
[0008] In addressing one or more of the above objectives, the
present inventors have recognized that a plurality of natural media
filtration agents may be utilized in a single bed to accomplish
wastewater polishing. More particularly, a first natural media
filtration agent may be utilized with a second, or even more,
natural media filtration agent(s) to produce a single treatment bed
capable of polishing a wastewater stream comprising a plurality of
contaminants. The natural media filtration agents utilized in the
bed generally include at least two of compost, bauxite residue,
activated alumina, iron filings, granular activated carbon, bone
char and aggregate. Multi-agent natural media filtration systems
are able to reduce pass-through of contaminants via various
mechanisms, such as, for example, restricted porosity, chemical
adsorption, chemical precipitation, and bio-degradation, among
others. For instance, the porosity of the bed may be tailored to
remove small particulates (e.g., particulates having a diameter of
at least about 0.5 .mu.m) while the natural media filtration agents
of the bed may be selected to increase bio-degradation, chemical
adsorption and/or chemical precipitation of contaminants dissolved
in the wastewater stream. Since a single bed may be employed with a
plurality of natural media filtration agents, the footprint of the
treatment system may be reduced relative to conventional
polishing-type treatment systems. In turn, lower hydraulic loading
rates may be witnessed. Furthermore, as the single treatment bed
employs natural media, the bed may be utilized in a wetlands
treatment approach, or a hybrid tank-wetlands approach, thereby
providing a cost-effective and environmentally friendly approach to
wastewater polishing.
[0009] In one aspect, a wastewater treatment system comprising a
single bed for polishing a wastewater stream comprising a plurality
of contaminants is provided. The treatment system comprises a
vessel, a wastewater inlet to the vessel and a wastewater outlet
from the vessel. In one approach, the vessel comprises a single
treatment bed containing at least two natural media filtration
agents. The vessel may be an in-ground pit or in-ground tank, an
above-ground tank, or a combination thereof. The wastewater inlet
is in fluid communication with at least one of the natural media
filtration agents of the bed, and the wastewater outlet is in fluid
communication with at least one of the natural media filtration
agents of the bed.
[0010] The bed comprises the at least two natural media filtration
agents. The natural media filtration agents may be any of compost,
bauxite residue, iron filings, granular activated carbon, activated
alumina, bone char and aggregate. In one embodiment, the first
natural media filtration agent of the bed is compost. In another
embodiment, the first natural media filtration agent of the bed is
bauxite residue. In another embodiment, the first natural media
filtration agent of the bed is iron filings. In another embodiment,
the first natural media filtration agent of the bed is bone char.
In another embodiment, the first natural media filtration agent of
the bed is granular activated carbon. In another embodiment, the
first natural media filtration agent of the bed is activated
alumina. The second natural media filtration agent of the bed is
one of compost, bauxite residue, iron filings, granular activated
carbon, activated alumina, bone char, and aggregate, wherein the
first natural media filtration agent is different than the second
natural media filtration agent. In one embodiment, the bed
comprises at least three of the natural media filtration agents. In
one embodiment, the bed comprises at least four of the natural
media filtration agents. In one embodiment, the bed comprises at
least five of the natural media filtration agents. In one
embodiment, the bed comprises at least six of the natural media
filtration agents. In one embodiment, the bed comprises at least
seven of the natural media filtration agents.
[0011] The plurality of natural media filtration agents may be
combined in the vessel bed in various configurations. In one
approach, the first and second natural media filtration agents are
commingled within the vessel bed. In another approach, the bed
comprises a plurality of separate filtration layers, each of which
comprises at least one natural media filtration agent. In one
approach, each layer comprises a single natural media filtration
agent. In a particular embodiment, a layer consists essentially of
a natural media filtration agent. In another approach, at least one
of the layers comprises at plurality of natural media filtration
agents. In one embodiment, the bed comprises a first filtration
layer and a separate second filtration layer, wherein the first
filtration layer comprises the first natural filtration media
agent, and wherein the second filtration layer comprises the second
natural media filtration agent.
[0012] In another aspect, methods of producing wastewater polishing
beds adapted to polish wastewater comprising a plurality of
contaminants are provided. In one approach, a method comprises the
steps of (a) determining a wastewater stream profile for a
wastewater stream that comprises a plurality of contaminants, the
wastewater stream profile comprising a wastewater contaminant
profile and at least one of a wastewater flow profile and a
wastewater effluent goal; (b) selecting a plurality of natural
media filtration agents for use in the wastewater polishing bed,
where:in this selecting step is based at least in part on the
wastewater contaminant profile, wherein a first one of the
plurality of natural media filtration agents is compost or bauxite
residue, and wherein a second one of the plurality of natural media
filtration agents is one of compost, bauxite residue, granular
activated carbon, iron filings, bone char and aggregate, the second
one of the plurality of natural media filtration agents being
different than the first one of the natural media filtration
agents; (c) selecting a single bed configuration based at least in
part on the first and second natural media filtration agents, and
further based in part on at least one of the wastewater flow
profile and the wastewater effluent goal; and (d) producing a
single treatment bed comprising the plurality of natural media
filtration agents based at least in part on the single bed
configuration.
[0013] In one embodiment, the wastewater contaminant profile
indicates the presence of at least one of aluminum, chlorine,
atrazine, and bioaccumulative organics (e.g., PCBs, PAHs), and a
selected natural media filtration agent is compost. In one
embodiment, the wastewater contaminant profile indicates the
presence of at least one of fluorides, nitrates, pathogens,
phosphates and arsenic, and a selected natural media filtration
agent is bauxite residue. In one embodiment, the wastewater
contaminant profile indicates the presence of at least one of
arsenic, cyanide, chromium, pathogens, and selenium, and a selected
natural media filtration agent is iron filings. In one embodiment,
the iron filings comprise zero valent iron. In one embodiment, the
wastewater contaminant profile indicates the presence of at least
one of chlorine, polychlorinated biphenyls, and polynuclear
aromatic hydrocarbons, and a selected natural media filtration
agent is granular activated carbon. In one embodiment, the
wastewater contaminant profile indicates the presence of at least
one of arsenic, fluoride and lead, and a selected natural media
filtration agent is bone char.
[0014] In one embodiment, the selecting a plurality of natural
media filtration agents step comprises selecting at least three
natural media filtration agents for use in the wastewater polishing
bed. In one embodiment, the selecting a plurality of natural media
filtration agents step comprises selecting at least four natural
media filtration agents for use in the wastewater polishing bed. In
one embodiment, the selecting a plurality of natural media
filtration agents step comprises selecting at least five natural
media filtration agents for use in the wastewater polishing bed. In
one embodiment, the selecting a plurality of natural media
filtration agents step comprises selecting at least six natural
media filtration agents for use in the wastewater polishing bed. In
one embodiment, the selecting a plurality of natural media
filtration agents step comprises selecting at least seven natural
media filtration agents for use in the wastewater polishing bed. In
one embodiment, a first one of the plurality of natural media
filtration agents is compost, a second one of the plurality of
natural media filtration agents is bauxite residue, and a third one
of the plurality of natural media filtration agents is one of
granular activated carbon, iron filings, bone char, activated
alumina, and aggregate.
[0015] In one aspect, methods of polishing wastewater utilizing the
wastewater polishing systems are provided. In one embodiment, after
the single bed is produced, such as described above, a method
includes the steps of flowing the wastewater stream through the
single treatment bed comprising the first and second natural media
filtration agents; removing at least a portion of a first
contaminant of the wastewater stream via the first one of the
natural media filtration agents; and removing at least a portion of
a second contaminant of the wastewater stream via the second one of
the natural media filtration agents. In one embodiment, the method
includes the step of discharging, after the flowing step, a
discharge water stream from the single treatment bed, wherein the
discharge water stream comprises not greater than legally allowed
limits of the first and second contaminants.
[0016] As may be appreciated, various ones of these inventive
aspects, approaches and embodiments may be combined to yield
various wastewater polishing systems having a single bed for
polishing a wastewater, and methods associated therewith. These and
other aspects, advantages, and novel features of the invention are
set forth in part in the description that follows and will become
apparent to those skilled in the art upon examination of the
following description and figures, or may be learned by practicing
the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 illustrates one embodiment of a wastewater polishing
system useful in accordance with the present invention.
[0018] FIG. 2 illustrates another embodiment of a wastewater
polishing system useful in accordance with the present
invention.
[0019] FIG. 3 is a flow chart illustrating one embodiment of a
method for producing a single treatment bed and polishing a
wastewater stream via a single treatment bed.
[0020] FIG. 4 is a flow chart illustrating various steps that may
be completed to determine a wastewater stream profile.
[0021] FIG. 5 is a flow chart illustrating various steps that may
be completed to produce a single treatment bed.
[0022] FIG. 6 is a schematic illustration of a test column
configuration.
[0023] FIGS. 7a-7j illustrate experimental data associated with the
testing of various columns comprising natural filtration media.
[0024] FIG. 8 is a schematic illustration of a compost bed employed
in treating industrial wastewater.
[0025] FIG. 9 illustrates experimental data associated with the use
of a compost bed to treat industrial wastewater.
DETAILED DESCRIPTION OF THE INVENTION
[0026] Reference will now be made in detail to the accompanying
drawings, which at least assist in illustrating various pertinent
features of the present invention. Referring now to FIG. 1, one
embodiment of a wastewater polishing system is illustrated. The
wastewater polishing system 1 includes a vessel 10 comprising an
inlet 20 and an outlet 30. The vessel 10 also includes a bed 40
comprising a plurality of natural media filtration agents that are
adapted to remove impurities, contaminants, and/or particulates and
the like from a wastewater stream 22 (i.e., a non-potable water
stream) passing through the bed 40. Thus, a water stream 32 exiting
the vessel 10 via outlet 30 will contain a reduced amount of
contaminants/impurities.
[0027] The bed 40 comprises at least two natural media filtration
agents, and those agents are selected based on the contaminants in
the wastewater stream. More particularly, the bed 40 comprises at
least two of the following natural media filtration agents:
compost, bauxite residue, activated alumina, granular activated
carbon, iron filings, bone char, and aggregate. Natural media
filtration agents are environmentally friendly agents that remove
contaminants from wastewater via physical, chemical and/or
biological processes (e.g., absorption, adsorption, entrainment,
precipitation, bio-degradation) as the wastewater communicates with
(e.g., passes by/flows through) the agent(s). The amount and type
of natural media filtration agents is selected based on the
contaminant profile of the wastewater stream 22 and/or suitable
contaminant levels of the exiting water stream 32.
[0028] Table 1, below, provides a listing of various contaminants
and natural media filtration agents that may be useful for removing
those contaminants from the wastewater stream. For example, for
wastewaters comprising polychlorinated biphenyls (PCBs), the bed 40
may include compost and/or granular activated carbon (GAC). For
wastewaters that comprise fluorides, the bed 40 may comprise
bauxite residue, bone char and/or activated alumina. Many other
contaminants and natural media filtration agent combinations may be
employed, some of which are discussed in further detail below. The
examples of Table 1 are non-limiting and are for illustration
purposes only as other non-listed contaminants may be contained
within the wastewater stream 22, and one or more of the natural
media filtration agents may be employed to remove such contaminants
from the wastewater stream 22.
TABLE-US-00001 TABLE 1 Contaminant Suitable removal agent(s)
Aluminum compost Arsenic activated alumina, bauxite residue, bone
char, iron filings Chlorine compost, granular activated carbon
Chromium iron filings Cyanides iron filings Fluorides activated
alumina, bauxite residue, bone char Herbicides/Pesticides compost,
bauxite residue Lead bone char Nitrogen (e.g., nitrates) bauxite
residue PAHs bauxite residue, compost, granular activated carbon
Pathogens bauxite residue, iron filings PCBs compost, granular
activated carbon Phosphorous (e.g., bauxite residue phosphates)
Selenium activated alumina, iron filings
[0029] As noted above, compost is useful in removing/filtering, for
example, various organic chemicals (e.g., bioaccumulative organics,
such as PCBs and PAHs) metals, halogens, and inorganic chemicals
(e.g., atrazine) to name a few. Compost may also be useful in
acting as a filler material, which provides structural support for
the bed 40 and/or assists in tailoring the porosity of the bed 40
so as to facilitate a suitable residence time (also known as
hydraulic retention time). The compost may be obtained from any
suitable source, such as by aerobically decomposing plant(s) and/or
animal(s). One particularly useful compost is mushroom-containing
compost. The compost may be in accordance with United States EPA
Class A or Class B standards (see 40 C.F.R. .sctn.503). Thus,
compost may be employed in the bed 40 as one or both of a
filtering/reaction material and as a filler material since compost
is relatively inexpensive, is widely available, and generally has a
suitable structural integrity to act as a filler material. Compost
is generally employed in the bed 40 with at least one other natural
media filtration agent.
[0030] Bauxite residue is useful in removing, for example,
pathogens (e.g., bacteria and/or viruses, such as coliform
bacteria), arsenic, eutrophication nutrients (e.g., nitrogen or
phosphorous containing nutrients, such as nitrates and phosphates),
and herbicides/pesticides, to name a few. Bauxite residue (also
known as red mud or brown mud) is a by-product of the Bayer Process
(i.e., the process of producing alumina from bauxite). The chemical
and physical properties of bauxite residue depend primary on the
type of bauxite used in the Bayer Process and, to a lesser extent,
the manner in which the bauxite is processed. Bauxite residue
generally contains alumina, silica and iron oxide. Bauxite residue
is relatively inexpensive (e.g., about $50 per ton) and is thus
preferred over more expensive natural filtration media suitable for
removal of similar contaminants (e.g., activated alumina, iron
filings). Bauxite residue is generally employed in the bed 40 as a
filtering/reaction material and is generally utilized within the
bed 40 with, at least, compost and/or aggregate. However, in some
instances, bauxite residue may be utilized without other natural
media filtration agents and/or may be employed as a filler
material.
[0031] Activated alumina is useful in removing/filtering, for
example, arsenic, fluorides, and selenium. Activated alumina is
generally obtained by dehydroxylating aluminium hydroxide and is
available from a variety of world wide merchants. Thus, activated
alumina may be employed in the bed 40 as one or both of a
filtering/reaction material, and is generally utilized in the bed
40 with at least one other natural media filtration agent. However,
in some instances, activated alumina may be utilized without other
natural media filtration agents and/or may be employed as a filler
material.
[0032] Granular activated carbon is useful in removing/filtering,
for example, various organic chemicals (e.g., PCBs, PAHs). The
granular activated carbon may be any suitable activated carbon in
particulate form. For example, the activated carbon may be obtained
from charcoal or coal. Granular activated carbon is generally
employed in the bed 40 as a filtering/reaction material and is
generally utilized within the bed 40 with, at least, compost and/or
aggregate. However, in some instances, granular activated carbon
may be utilized without other natural media filtration agents
and/or may be employed as a filler material.
[0033] Iron filings are useful in removing/filtering, for example,
various pathogens, cyanide complexes, chromium, selenium and
arsenic, to name a few. Iron filings generally comprise zero valent
iron (ZVI), but may include other types of iron. Iron filings are
generally employed in the bed 40 as a reaction material. Iron
filings are relatively more expensive than other natural filtration
media, and are thus less preferred in some instances. Iron filings
are generally in particulate or ribbon form and are generally
utilized within the bed 40 with, at least, compost and/or
aggregate. However, in some instances, iron filings may be utilized
without other natural media filtration agents and/or may be
employed as a :filler material.
[0034] Bone char is useful in removing/filtering, for example,
fluorides, arsenic, and lead. Bone char, also known as bone black
or animal charcoal, generally comprises carbon and calcium
phosphate and is produced from calcining animal bones. Bone char is
generally employed in the bed as a filtering/reaction material and
is generally utilized within the bed 40 with, at least, compost
and/or aggregate. However, in some instances, bone char may be
utilized without other natural media filtration agents and/or may
be employed as a filler material.
[0035] Aggregate is useful in filtering materials entrained within
the wastewater (e.g., total suspended solids). Aggregate generally
comprises sand and/or gravel. Aggregate is also useful in acting as
a structural support for the bed 40 and/or in tailoring the
porosity of the bed 40 to facilitate a suitable residence time.
Aggregate is generally employed within the bed 40 as a filtering
material and is generally employed with at least one of and
typically at least two of compost, bauxite residue, activated
alumina, iron filings, granular activated carbon and bone char.
[0036] The above-described natural media filtration agents may be
combined in any ratio(s) and/or amount(s) to treat the wastewater
stream 22 via bed 40. These combinations and ratios are generally
application specific. In one embodiment, the wastewater stream 22
may comprise coliform bacteria and the bed 40 may comprise bauxite
residue and aggregate to treat the coliform bacteria. In this
embodiment, the bauxite residue to aggregate ratio may be at least
about 2:1, such as at least about 3:1, or at least about 5:1, by
volume. In this embodiment, the bauxite residue to aggregate ratio
may be not greater than 10:1. In other embodiments, bauxite residue
may be employed as a layer of the bed 40, where this layer is
comprised mainly of, and in some instances consists essentially of,
bauxite residue.
[0037] In another embodiment, the wastewater stream may comprise
cyanide, and the bed 40 may comprise iron filings and aggregate to
treat the cyanide. In this embodiment, the iron filings to
aggregate ratio may be at least about 1:5, such as at least about
1:1, by volume.
[0038] The natural media filtration agents may be utilized within
the bed 40 in any arrangement that facilitates removal of
contaminants from the wastewater while allowing a suitable
residence time of the water. For example, and as illustrated in
FIG. 1, the natural media filtration agents may be commingled as a
single bed layer.
[0039] In another embodiment, and as illustrated in FIG. 2, the bed
40 may comprise a plurality of distinct layers, each of which may
comprise one or more of the natural media filtration agents. By way
of illustration, a first layer 42 may comprise a first natural
media filtration agent (e.g., compost), a second layer 44 may
comprise a mixture of second and third natural media filtration
agents (e.g., iron filings and aggregate), and a third layer 46 may
comprise a mixture of fourth and fifth natural media filtration
agents (e.g., bauxite residue and aggregate). Thus, the bed 40 may
comprise a plurality of filtering layers that may be tailored to
remove one or more contaminants from the wastewater, each of the
plurality of layers including at least one natural media filtration
agent. One or more of these plurality of layers may also be
tailored to facilitate a suitable residence time by tailoring the
porosity of the layer via one or more of the natural media
filtration agents.
[0040] The amount of each natural media filtration agent utilized
in the bed is application specific and is a function of, for
example, wastewater contaminant levels, effluent goals, and
wastewater flow rates, to name a few. General, non-limiting
guidelines regarding amounts of natural media filtration agents
that may be used per contaminant are provided in Table 2,
below.
TABLE-US-00002 TABLE 2 Suitable removal Empty Bed Contact Surface
Loading Contaminant agent(s) Time (minutes) Rate (lpm/n.sup.2)
Aluminum compost 50-1600 1.2-12.2 Arsenic bauxite residue, 5-10
20.3-40.7 activated alumina, iron filings Chlorine compost,
granular ~60 ~16.3 activated carbon Cyanides iron filings 20-100
6.1-11.4 Fluorides bauxite residue, ~100 ~4.1 bone char, activated
alumina Pathogens bauxite residue, 50-90 8.1-20.3 iron filings PCBs
compost, granular 50-1600 1.2-12.2 activated carbon Phosphorous
bauxite residue 40-90 8.1-20.3 Selenium iron filings, 5-10
20.3-40.7 activated alumina Others misc. 5-1600 0.5-40.7
[0041] The vessel 10 may be any suitable container adapted to
contain the bed 40 and interface with the inlet 20 and the outlet
30. In one embodiment, the vessel 10 is an in-ground pit utilized
in a wetlands treatment arrangement. Other configurations may also
be employed, such as in-ground or above-ground columns and tanks,
and hybrids of any of these, such as a vessel that includes both an
in-ground pit and a tank interconnected therewith, to name a few.
The vessel 10 holds the bed 40; both should be configured to
facilitate removal of a desired amount of contaminants from the
wastewater stream 22 (e.g., so as to produce an exiting water
stream 32 that is in accordance with local laws/regulations). Thus,
the size of the bed 40, and thus the vessel 10, is generally
application specific, and is generally based on one or more of the
residence time of the water within the bed 40, the bed materials
utilized within the bed 40, such as the natural media filtration
agents utilized within the bed 40, the concentration of natural
media filtration agents within the bed 40, and the
filtration/reaction rates of the natural media filtration agents of
the bed 40.
[0042] As noted, since the system 1 is a polishing type system its
configuration is generally applicable to low flow treatment
arrangements. In this regard, the bed 40 and/or vessel 10 may be
configured to facilitate a suitable hydraulic loading rate and/or
residence time. For example, the bed and/or vessel may be
configured to have a hydraulic loading rate of not greater than 1
gallon per minute per square foot (40.7 liters per minute per
square meter), such as not greater than 0.1 gallon per minute per
square foot ((4.1 liters per minute per square meter). In one
embodiment, the hydraulic loading rate is at least 0.01 gallon per
minute per square foot (0.4 liters per minute per square meter). In
one embodiment, the residence time is at least 2 hours, such as at
least 8 hours. In one embodiment, the residence time is not greater
than 48 hours, such as not greater than 24 hours.
[0043] Since the vessel 10 and bed 40 may be sized to facilitate
removal of contaminants to a suitable level, the water stream 32
exiting the vessel 10 will generally comprise a contaminant level
that is less than a pre-determined standard. This standard may be
one or more of an international, national, state, provincial,
county and/or municipal law/regulation/guideline, and the exiting
water stream 32 may contain contaminant levels that are in
accordance with one or more of those standards. For instance, the
water stream 32 may contain not greater than legally permitted
levels of in no particular order, PCBs, chlorines, fluorides,
polynuclear aromatic hydrocarbons (PAHs), bacteria, viruses,
herbicides, pesticides, eutrophication nutrients (e.g., nitrates,
phosphates), arsenic, cyanides, metals (e.g., Al, Cr, Pb), and/or
selenium. In some embodiments, the exiting water stream 32 may
comprises non-detectable levels of contaminants, such as low ppt
levels of various contaminants. Thus, the exiting water stream 32
may be suitable for discharge to the environment, such as via
groundwater injection.
[0044] As noted above, a vessel inlet 20 is utilized to provide the
wastewater stream 22 to the vessel 10. The vessel inlet 20 may be
any suitable type of apparatus that facilitates fluid communication
between the wastewater stream 22 and the bed 40, such as pipes,
sieves and the like. As noted above, since the system 1 is
generally suitable for polishing wastewater, as opposed to treating
heavy polluted wastewaters, the wastewater stream 22 entering the
vessel 10 generally should comprise contaminant levels that are
suitable for treatment via a polishing-type system. Furthermore,
the wastewater stream should be amenable to low-flow treatment
systems, such as via the residence times and/or hydraulic loading
rates provided above. With respect to contaminant levels, the
maximum permitted contaminant level of the wastewater stream 22 is
application specific and is a function of, for instance, the types
and amounts of contaminants within the wastewater stream 22, as
well as the desired vessel 10 volume and desired lifetime of the
system 1, to name a few. In one approach, the wastewater stream 22
should may include not greater than about 100 mg/L of contaminants,
such as, for example, part-per-billion (ppb) and/or
part-per-trillion (ppt) levels of contaminants. Some examples of
types of wastewaters that may be polished using the system 1
include sanitary sewage effluents after activated sludge treatment,
industrial cooling waters, industrial wastewaters, combined sewer
overflow, and storm runoff, to name a few.
[0045] As noted above, the vessel outlet 30 is utilized to
discharge the exiting water stream 32. Any suitable apparatus may
be utilized as the vessel outlet 30. For example, any suitable type
of piping/sieve may be utilized. The vessel inlet 20 and outlet 30
are generally positioned relative to one another to facilitate a
suitable residence time of contaminated water within the vessel 10.
Thus, the inlet 20 may be positioned above, proximal, transverse to
or otherwise next to the bed 40, or a layer thereof (e.g., a top
layer). Likewise, the outlet may be positioned below, proximal,
transverse or otherwise next to the bed 40, or a layer thereof
(e.g., a bottom layer).
[0046] Methods of producing wastewater treatment beds and methods
of polishing/treating wastewater streams via the single wastewater
treatment beds are also provided. One embodiment of a method for
producing a wastewater treatment bed is illustrated in FIG. 3. In
the illustrated embodiment, the method includes the steps of
determining a wastewater stream profile 100 and producing a single
treatment bed based on the wastewater stream profile 200. The
method may also include the step of treating a wastewater stream
via the produced single wastewater treatment bed 300.
[0047] Referring now to FIG. 4, the step of determining a
wastewater stream profile 100 may include one or more of, and often
at least two of, or even all of, the steps of determining a
wastewater stream contaminant profile 120, determining a wastewater
stream flow profile 140 and determining a wastewater stream
effluent goal 160.
[0048] The step of determining a wastewater contaminant profile 120
may be completed by various known techniques, such as sampling and
analysis. This step 120 is important to determine the types and
quantities of the contaminants in the wastewater stream, which
facilitates selection of the natural media filtration agents and
the amounts of those natural media filtration agents to be utilized
within the system. For example, as described above, the wastewater
stream may currently contain, or may be anticipated to contain at a
later date, organic chemicals, organisms, inorganic chemicals,
heavy metals, cyanide complexes, alkali metals, alkaline-earth
metals, group V-A elements, halogens and/or semiconductors, to name
a few. A plurality of the natural media filtration agents may be
selected based on the wastewater contaminant profile, such as in
accordance with Table 1, above.
[0049] The step of determining a wastewater stream flow profile 140
may be completed by various known techniques, such as by modeling
and/or physical measurement. The flow profile may include
wastewater flow information such as average flow rate, seasonal
flow rates, maximum flow rates, and minimum flow rates, to name a
few. This information may be useful in facilitating sizing of the
bed and/or vessel of the treatment system and/or selection of the
natural media filtration agents. For example, a residence time
and/or hydraulic loading rate of the vessel/bed may be determined
utilizing flow profile information.
[0050] The step of determining a wastewater stream effluent goal
160 generally comprises determining the amounts of contaminants
that are acceptable for discharge from the treatment system. For
example, various standards, such as those described above, may be
utilized to determine the wastewater effluent goal. This
information may be useful in facilitating sizing of the bed and/or
vessel of the treatment system and/or selection of the natural
media filtration agents. For example, a residence time and/or
hydraulic loading rate of the vessel/bed may be determined
utilizing effluent goal information.
[0051] Referring now to FIG. 5, once the wastewater stream profile
has been determined 100, the single treatment bed may be produced
200. The step of producing the single treatment bed may include the
step of selecting a plurality of natural media filtration agents
for the bed/system 220 and selecting a configuration of the single
treatment bed 240.
[0052] The selected media step 220 may be based on, for example,
the wastewater contaminant profile 120, where suitable natural
media filtration agents are selected to remove contaminants of the
wastewater stream. For example, a first natural media filtration
agent may be selected based on a first contaminant of the
wastewater stream and a second natural media filtration agent may
be selected based on a second contaminant of the wastewater stream,
where the first natural media filtration agent is effective in
removing the first contaminant from the wastewater stream and the
second natural media filtration agent is effective in removing the
second contaminant from the wastewater stream. Furthermore, the
first and/or second natural media filtration agents may be
effective in removing other contaminants from the wastewater
stream. Thus, the bed may comprise, and in some instances consist
essentially of, the first and second natural media filtration
agents in commingled or layered configuration. Nonetheless, third,
fourth, fifth, sixth and seventh natural media filtration agents
may also be selected to remove third, fourth, fifth, sixth and/or
additional contaminants, respectively, from the wastewater stream.
Thus, the bed may comprise three, four, five, six or even seven
natural media filtration agents, in commingled and/or layered
configuration, and in some embodiments may consist essentially of
those three, four, five, six or seven natural media filtration
agents, respectively.
[0053] Irrespective of the contaminants of the wastewater stream,
the bed should include at least one of a filtering filler material
and should also include one of a filtering additive. In one
embodiment, the filtering filler material is at least one of
compost and aggregate, as illustrated in box 224. In a related
embodiment, the filtering additive is at least one of bauxite
residue, activated alumina, iron fillings, granular activated
carbon and bone char, as illustrated in box 226. The filtering
filler generally acts as a structural support for the bed, and also
provides a mechanism to create layered and/or commingled
configurations within the bed, while the filtering additive is an
additive that is generally employed with a filtering filler, and
acts to physically, chemically and/or biologically interact with
contaminants of the wastewater stream to remove those contaminants
from the wastewater stream. In some instances, the filtering filler
material may also to chemically and/or biologically interact with
contaminants of the wastewater stream to remove those contaminants
from the wastewater stream, such as via the use of compost.
Generally, the filtering filler materials are less expensive than
the filtering additives and are thus employed as a filler, although
in some instances the filtering additives may be utilized as
fillers. By way of illustration, compost may be mixed with bauxite
residue to produce a commingled single layered bed. In another
example, the bed may comprise a first layer of compost material and
a separate second layer comprising bauxite residue commingled with
aggregate. Thus, in this example, the compost acts as both a
filtering filler material and a filtering additive for the first
layer, and the aggregate acts as a filtering filler for the second
layer. In turn, the bauxite residue acts as a filtering additive
for the second layer being commingled with the aggregate. Other
configurations are possible, and include any of the permutations
and combinations of the listed filtering fillers and filtering
additives.
[0054] The natural filtration media agents may also be selected
based on the porosity/retention capability of the natural media
filtration agent, and hence the step of selecting the natural media
filtration agents 220 may be based on one or more of the flow
profile information and/or the effluent goal information of the
wastewater stream. For example, natural media filtration agents may
be selected to achieve a suitable residence time/hydraulic loading
rate within the bed/system, which is related to the
porosity/retention capability of the natural media filtration
agents. The configuration of the bed, discussed below, may also be
used to facilitate a suitable residence time/hydraulic loading rate
within the bed/system.
[0055] As noted above, the step of producing the single treatment
bed generally involves the step of selecting a configuration of the
single treatment bed 240. For instance, one or more of a commingled
242 or layered 244 configuration may be selected. The selected
configuration may be based on one or more of the wastewater stream
contaminant profile 120, the wastewater stream flow profile 140,
the wastewater stream effluent goal 160, and the selected natural
media filtration agents 220. By way of illustration, the bed may be
configured to facilitate a suitable residence time/hydraulic
loading rate 246 as based on the selected natural media filtration
agents, wherein various ones of the natural media filtration agents
are layered and/or commingled to achieve the a suitable residence
time/hydraulic loading rate. The configuration may allow for flow
gradients within the bed so as to facilitate the residence time.
The configuration may also allow for sizing of the bed to achieve a
desired bed lifetime. The configuration may be restricted based on
the volume available for the vessel, and thus the step of selecting
a configuration and the step of selecting the natural media
filtration agents may be interrelated, as illustrated by arrows
275, to achieve the effluent goal within the available volume.
[0056] After the natural media filtration agents and the
configuration have been selected, the bed may be produced 200, such
as via production of an in-ground pit, followed by insertion of the
natural filtration media filtration agents into the pit. If a
layered configuration is utilized, the natural filtration media for
the layer may be produced (e.g., via mixing of the selected natural
media filtration agents for that layer), followed by production of
the layer within the pit (e.g., via dumping and/or leveling).
Concomitantly, the inlets and/or outlets of the pit may be produced
and interconnected with suitable piping/sieves. Since the bed is
comprised mainly of natural media filtration agents and comprises a
tailored porosity, the bed will require little maintenance, is
environmentally friendly, and may have a long lifetime (e.g., 20-30
years). Furthermore, the use of natural filtration media may be
relatively inexpensive. System replacement costs may thus be
relatively inexpensive, and therefore infrequent bed replacement
may not be overly burdensome.
[0057] Referring back to FIG. 3, after the single treatment bed has
been produced, the wastewater stream may be polished utilizing the
single treatment bed 300. For example, the wastewater stream may
flow through the single treatment bed wherein contaminant levels of
the wastewater stream are reduced, such that the wastewater stream
may be discharged in compliance with one or more federal, state
and/or local laws. More particularly, at least a first portion of a
first contaminant may be removed from the wastewater stream via a
first one of the natural media filtration agents. A second
contaminant of the wastewater stream may be removed by a second one
of the natural media filtration agents. Other contaminants may also
be removed via the plurality of natural media filtering agents. The
exiting water stream may thus be discharged to the environment.
EXAMPLES
[0058] Bauxite Residue and Iron Filings Columns
[0059] As schematically illustrated in FIG. 6, sanitary wastewater
612 from a reservoir 610 was flowed through a column 640 comprising
a natural media filtration arrangement to an effluent reservoir 650
via a pump 620. A pressure gauge 630 was used to monitor the inlet
pressure to the column 640. The column 640 was a 2.5 cm inner
diameter PVC column comprising 30 cm in height of a natural media
filtration arrangement surrounded by 2.5 cm in height glass wool
filters on either side of the natural media filtration arrangement.
Four different natural media arrangements were utilized:
[0060] a. Column 1--commercial filter sand
[0061] b. Column 2--sand and iron filings in a 1:1 ratio, by
volume
[0062] c. Column 3--bauxite residue and sand in a 3:1 ratio, by
volume
[0063] d. Column 4--bauxite residue and sand in a 5:1 ratio, by
volume
[0064] Treated sanitary wastewater was passed through each column
in an upflow mode at a flow rate of 1 mL/min, which corresponds to
an empty bed contact time for each of the columns of 150 minutes.
The influent and effluent of each column were monitored regularly
for total and fecal coliform bacteria. The results of these tests
are illustrated in FIGS. 7a-7j. During two different sampling
events, 20 different inorganic compounds were analyzed in both the
influent and effluents for all four columns. The test results of
these sampling events are illustrated in FIGS. 7i-7j.
[0065] With respect to bacteria removal, Columns 2 and 4 were able
to achieve an average percent reduction of 97+ percent in total
coliform bacteria, and an average percent reduction of 99+ percent
in fecal coliform bacteria, with the majority of the data being
non-detect (detection limit=0 coliforms/100 mL). In many areas, the
regulatory limit for kcal coliform is less than 200 coliforms/100
ml. The percentage reduction of coliform in Columns 1 and 3
indicates that the amount of iron in the sand/bauxite residue may
play a role in the removal of coliform.
[0066] With respect to the two sampling events, the results of
which are illustrated in FIGS. 7i-7j, there were no significant
differences in the profile scan for Columns 1 and 3. Columns 2 and
4 reduced Si by 56%, Ca by 20% and phosphorus (P) by 100%.
Additionally, Column 4 reduced both Mg and K by 50%.
[0067] Compost Removal of PCBs and Aluminum
[0068] A full-scale compost-based bed was constructed, a schematic
view of which is illustrated in FIG. 8. The bed included an
aggregate base layer 820 having a height of about 9 centimeters and
included drainage pipes 830 fluidly interconnected therewith. A
compost layer 810 having a height of about 60 centimeters was
provided on top of the base layer. A freeboard layer 800 was
included above the compost layer 810. The bed was designed to
satisfy a hydraulic loading of from 0.01 to 0.1 gallons per minute
per square foot (0.4 to 40.7 lpm/m.sup.2) and a residence time of
from 2.5 to 24 hours. Wastewaters from an industrial facility were
passed through the bed at a rate of between about 70,000 and
400,000 gallons per day (about 265,000 and 1,520,000 liters per
day) for a period of several months. The total suspended solids of
the influent was not greater than 10 ppm, and the total suspended
solids particle range was from 0.5 to 10 .mu.m. Effluent water from
the compost bed was periodically tested for PCBs and aluminum. The
test results for PCBs are illustrated in FIG. 9. For the tested
effluent samples, between 70-100% of aluminum was removed from the
wastewater, with the majority of the tested effluent samples
measuring non-detect for aluminum at a detection limit of 0.05
mg/L. All effluent samples were non-detect for PCBs at a detection
limit of 0.0001 mg/L (0.1 ppb).
[0069] Compost Removal of Chlorine
[0070] Cooling water containing chlorine (from municipal water) was
treated using a vertical flow cell. The cell include a top bed of
compost having height of about 55 centimeters, a volume of about
0.72 cubic meters and a cross-sectional area of about 1.3 square
meters. The cell included a bottom bed of aggregate having a height
of about 15 centimeters, a volume of about 0.2 cubic meters, and a
cross-sectional area of about 1.3 square meters. After a residence
time of 24 hours, total residual chlorine was reduced from an
initial concentration of 1-2 mg/L to a concentration of <0.02 to
about 0.05 mg/L, with no free chlorine detected in the effluent at
the 0.02 mg/L analytical detection level.
[0071] Herbicides/Pesticides Removal Using Compost
[0072] To test the effectiveness of compost in removing
herbicides/pesticides from water, tests were conducted using the
popular herbicide ingredient atrazine. An atrazine stock solution
comprising 1 g/ml of atrazine was prepared and a series of isotherm
equilibrium tests were performed using grow green compost. Compost
showed significant removal of atrazine from stock solution. As
shown in Table 3, below, atrazine was reduced from approximately 1
to 0.06 mg/1 at the highest dose (i.e., 10 g compost per 100
milliliters of atrazine solution).
TABLE-US-00003 TABLE 3 Compost dose Mixture Filtrate atrazine
(g/100 ml) pH concentration (mg/L) 0.01 5.68 0.87 0.1 5.8 0.89 1
6.35 0.3 10 6.85 0.06
[0073] Fluoride Removal Via Bauxite Residue
[0074] Simple batch adsorption studies were performed to assess the
ability of bauxite residue to remove fluorides from wastewater. 250
mL glass vials containing varying dosage of sorbents from 25 g/L to
100 g/L were produced. The sorbate included between 64-73 mg/L
dissolved fluorine from a wastewater with a high concentration of
sulfate. Studies were conducted for 4 days and data was acquired
after 2 hours, 24 hours and 96 hours. Fluoride removal increased
from 35% to 82% as the sorbent loading was increased from 25 g/L to
100 g/L. The sorbate loading ranged from 1-2 mg of fluoride per g
of bed at the end of 24 hours.
[0075] While various embodiments of the present invention have been
described in detail, it is apparent that modifications and
adaptations of those embodiments will occur to those skilled in the
art. However, it is to be expressly understood that such
modifications and adaptations are within the spirit and scope of
the present invention.
* * * * *