U.S. patent application number 12/581686 was filed with the patent office on 2019-02-07 for filtration media for filtration/purification of a liquid or gas, related reactor modules, filtration devices and methods.
This patent application is currently assigned to BioAir Solutions, LLC. The applicant listed for this patent is Louis D. Le Roux. Invention is credited to Louis D. Le Roux.
Application Number | 20190039001 12/581686 |
Document ID | / |
Family ID | 42106944 |
Filed Date | 2019-02-07 |
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United States Patent
Application |
20190039001 |
Kind Code |
A1 |
Le Roux; Louis D. |
February 7, 2019 |
Filtration Media for Filtration/Purification of a Liquid or Gas,
Related Reactor Modules, Filtration Devices and Methods
Abstract
The invention includes a filtration medium for the purification
of a liquid or a gas material that includes a mat having a first
surface and a second surface. At least one of the first surface or
the second surface is substantially non-planar. The mat comprises a
foamed resin having a density of about 1 lbs/ft3 to about 3 lbs/ft3
and/or an indentation load deflection of about 35 lbs to about 150
lbs. Also included in the invention is a filtration medium for the
purification of a liquid or a gas material comprising at least two
mats, each mat having a first surface and a second surface, wherein
at least one of the first surface or the second surface is
substantially non-planar and has a substantially non-uniform
convolution profile. Included are devices for the filtration of a
liquid and/or a gas that comprise one or more reactor modules. The
reactor modules include the filtration medium and a substantially
cylindrical chamber and/or a substantially rectangular chamber that
may include sides, a top and a bottom. The chamber additionally
includes a base that extends from the sides of the chamber towards
the interior of the chamber and the filtration medium is disposed
within the chamber. Methods of filtering a gas or liquid material
using the filtration medium are also provided, as are methods of
fabrication of the modules.
Inventors: |
Le Roux; Louis D.;
(Voorhees, NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Le Roux; Louis D. |
Voorhees |
NJ |
US |
|
|
Assignee: |
BioAir Solutions, LLC
Voorhees
NJ
|
Family ID: |
42106944 |
Appl. No.: |
12/581686 |
Filed: |
October 19, 2009 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61106467 |
Oct 17, 2008 |
|
|
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B01D 29/117 20130101;
B01D 2239/0421 20130101; B01D 29/0022 20130101; B01D 2239/069
20130101; B01D 2239/0428 20130101; B01D 35/02 20130101; B01D
39/1676 20130101; B01D 2239/0695 20130101 |
International
Class: |
B01D 29/00 20060101
B01D029/00 |
Claims
1.-37. (canceled)
38. A filtration medium comprising at least one mat having a first
surface and a second surface, wherein at least one of the first
surface or the second surface is substantially non-planar having a
convolution profile formed by convolutions that are arranged on the
first surface of the mat so that when the mat is viewed in
sequential cross sections, a convolution viewed in a first cross
section is located along the mat in a different place than a
convolution of a subsequent cross section, and the mat is formed
into cylindrical format so that the first surface is in contact
with the second surface, wherein the placement of the convolutions
creates non-uniform channels that provide turbulence to the gas or
liquid being passed through the filter, and the mat comprises a
foamed resin that has a density of about 1 lbs/ft.sup.3 to about 3
lbs/ft.sup.3 and/or an indentation load deflection of about 35 lbs
to about 150 lbs, wherein the filtration medium is inoculated with
a biomass that oxidizes or breaks down odorous compounds in the
liquids and/or gases as they pass across the medium.
39. The filtration medium of claim 38 wherein the at least one
non-planar surface is present at the exterior of the cylindrical
format.
40. The filtration medium of claim 39, wherein the contact between
the first surface and the second surface is substantially
continuous.
41. The filtration medium of claim 39, wherein the convolution
profile is chosen from an egg crate profile, a zig-zag profile, a
rectangular profile, a projecting villi profile, a compound
projecting villi profile, and a V-shaped profile.
42. The filtration medium of claim 39, wherein the convolution
profile is a sine profile.
43. The filtration medium of claim 39, wherein the at least
non-planar surface comprises a profile that has a peak-to-valley
dimension of about 0.5 to about 0.75 inches.
44. The filtration medium of claim 39, wherein the density of the
foamed resin is about 1.2 lbs/ft.sup.3 to about 2.5
lbs/ft.sup.3.
45. The filtration medium of claim 39, wherein the density of the
foamed resin is about 1.8 lbs/ft.sup.3.
46. The filtration medium of claim 39, wherein the foamed resin
comprises a material chosen from polyurethane, nylon, polystyrene,
polypropylene, polyethylene and copolymers thereof.
47. The filtration medium of claim 39, wherein the foamed resin is
chosen from a hydrophobic material and a hydrophilic material.
48. The filtration medium of claim 39, wherein the foamed resin has
a nominal pore size of about 5 ppi to about 70 ppi.
49. The filtration medium of claim 39, wherein the mat comprises at
least a first layer and a second layer, and the first layer
comprises a foamed resin having a first density and the second
layer comprises a foamed resin having a second density, wherein the
first density is greater than the second density.
50. The filtration medium of claim 39, wherein the mat comprises at
least a first layer and a second layer, and the first layer
comprises a foamed resin having a first indentation load deflection
and the second layer comprises a foamed resin having a second
indentation load deflection, wherein the first indentation load
deflection is greater than the second indentation load
deflection.
51. The filtration medium of claim 39, wherein the mat comprises at
least a first layer and a second layer, and the first layer
comprises a foamed resin having a first pore size and the second
layer comprises a foamed resin having a second pore size, wherein
the first pore size is greater than the second pore size.
52. (canceled)
53. A filtration medium comprising at least one mat having a first
surface and a second surface, wherein at least one of the first
surface or the second surface is substantially non-planar having a
convolution profile formed by convolutions that are arranged on the
first surface of the mat so that when the mat is viewed in
sequential cross sections, a convolution viewed in a first cross
section is located along the mat in a different place than a
subsequent cross section, and the mat is formed into cylindrical
format so that the first surface is in contact with the second
surface wherein the placement of the convolutions creates
non-uniform channels that provide turbulence to the gas or liquid
being passed through the filtration medium, and the filtration
medium is inoculated with a biomass that oxidizes or breaks down
odorous compounds in the gases as they pass across the medium.
54. A module for the filtration of a gas comprising a reactor
module that comprises: a) the filtration medium comprising at least
one mat having a first surface and a second surface, wherein at
least one of the first surface or the second surface is
substantially non-planar and has a convolution profile formed by
convolutions that are arranged on the first surface of the mat so
that when the mat is viewed in sequential cross sections, a
convolution viewed in a first cross section is located along the
mat in a different place than a subsequent cross section, and the
mat is formed into cylindrical format around a hypothetical winding
axis so that the first surface is in contact with the second
surface wherein the placement of the convolutions creates
non-uniform channels that provide turbulence to the gas or liquid
being passed through the filtration medium; and b) a chamber having
sides and a base, wherein the base comprising a support that
extends from the sides of the chamber towards the interior of the
chamber, wherein the filtration medium is disposed within the
chamber.
55. The module of claim 54, wherein the chamber is a substantially
cylindrical chamber and the filtration medium is disposed within
the chamber such that the hypothetical winding axis of the mat is
substantially parallel to the sides of the chamber.
56. The module of claim 54, further comprising an inlet for
conveying the gas into the chamber and an outlet for conveying a
filtrate out of the chamber.
57. A filtration device that comprises at least two modules of
claim 54.
58. The device of claim 57, wherein the reactor module further
comprises a lid that extends over at least a portion of a top of
the chamber of at least one module.
59. A method of filtering a gas comprising: providing a filtration
medium that comprises at least one mat having a first surface and a
second surface, wherein at least one of the first surface or the
second surface is substantially non-planar having a convolution
profile formed by convolutions that are arranged on the first
surface of the mat so that when the mat is viewed in sequential
cross sections, a convolution viewed in a first cross section is
located along the mat in a different place than a subsequent cross
section, wherein the medium is inoculated with a biomass that
oxidizes or breaks down odorous compounds in the gases as they pass
across the filtration medium; and passing the gas to be filtered to
the filtration medium.
60. A method of fabricating a module for use in the filtration of a
gas comprising: winding a mat around a hypothetical winding axis at
a winding tension of about 1 to about 40 lbs per foam width
(foot)-to form a medium in a cylindrical format, inoculating the
medium with a biomass that is capable of oxidizing or breaking down
odorous compounds in the gases as they pass across the medium,
placing the medium in a chamber to form a module, wherein the mat
comprises a first surface and a second surface, wherein at least
one of the first surface or the second surface is substantially
non-planar having a convolution profile formed by convolutions that
are arranged on the first surface of the mat so that when the mat
is viewed in sequential cross sections, a convolution viewed in a
first cross section is located along the mat in a different place
than a subsequent cross section.
61. The filtration medium of claim 38, wherein the filtration
medium oxidizes or breaks down odorous compounds in gases as they
pass across the medium.
62. A filtration medium comprising at least one mat, each having a
first surface and a second surface, wherein the first surface of
the mat has a convolution profile formed by convolutions that are
arranged on the first surface of the mat so that when the mat is
viewed in sequential cross sections, a convolution viewed in a
first cross section is located along the mat in a different place
than a convolution of a subsequent cross section, and the mat is
arranged so that the first surface is in contact with the second
surface so that the placement of the convolutions creates
non-uniform channels that provide turbulence to the gas or liquid
being passed through the filter, and the mat comprises a foamed
resin that has a density of about 1 lbs/ft3 to about 3 lbs/ft3
and/or an indentation load deflection of about 35 lbs to about 150
lbs,
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims priority under 35 U.S.C. .sctn.
119(e) to U.S. Provisional Patent Application No. 61/106,467, filed
Oct. 17, 2008, the entire disclosure of which is incorporated
herein by reference.
BACKGROUND OF THE INVENTION
[0002] Larger scale biological purification/filtration of gas and
liquid materials requires correspondingly larger scale
purification/filtration devices, including filtration media. The
design and development of such devices is limited by several
parameters, for example, the need for large specific surface area
filter media (to increase efficiency), the tendency of filtration
media to collapse or fold under the combined load of biomass and
liquid, and the commercial pressure to minimize the footprint of
the device. Filter media composed of a corrugated bacterial bed
rolled into a "jelly roll" configuration with spaced apart channels
for water flow have been suggested for use in the purification of
sewer water. Other prior art devices use external structures to
provide structural strength to the media material within the
reactor vessels, for example "wagon wheel" configured metal
scaffolding around which filter media is disposed or web-like
support elements that encased the filter media. However, the
external structures alone cannot prevent collapse of the media and
such configurations may be prone to clogging by excess biomass.
Moreover, the scaffold-like support structures occupy space in the
reactor that could be filled by `live` media, thereby eroding the
efficiency of the system.
[0003] Thus, there remains need in the art for filtration media,
modules and devices that optimize performance of the filtration
activity, including optimizing mass transfer (and therefore
optimization of filtration/biological oxidation efficiency),
provide for retention of more microorganisms per unit of volume of
media, and that enhance the "life expectancy" of the filtration
media itself, allowing for longer use before replacement or
maintenance (necessitated, for example, by collapse of mat material
or clogging of mat with biomass that has overproliferated) as
compared to conventional filtration equipment.
[0004] BRIEF SUMMARY OF THE INVENTION
[0005] The invention includes a filtration medium for the
purification of a liquid or a gas material that includes a mat
having a first surface and a second surface. At least one of the
first surface or the second surface is substantially non-planar.
The mat comprises a foamed resin having a density of about 1
lbs/ft.sup.3 to about 3 lbs/ft.sup.3 and/or an indentation load
deflection of about 35 lbs to about 150 lbs.
[0006] Also included in the invention is a filtration medium for
the purification of a liquid or a gas material comprising at least
two mats, each mat having a first surface and a second surface,
wherein at least one of the first surface or the second surface is
substantially non-planar and has a substantially non-uniform
convolution profile.
[0007] Included are devices for the filtration of a liquid and/or a
gas that comprise one or more reactor modules. The reactor modules
include the filtration medium and a substantially cylindrical
chamber and/or a substantially rectangular chamber that may include
sides, a top and a bottom. The chamber additionally includes a base
that extends from the sides of the chamber towards the interior of
the chamber and the filtration medium is disposed within the
chamber.
[0008] Methods of filtering a gas or liquid material using the
filtration medium are also provided, as are methods of fabrication
of the modules.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] The foregoing summary as well as the following detailed
description of embodiments of the invention may be better
understood when read in conjunction with the appended drawings. It
should be understood, however, that the invention is not limited to
the precise arrangements and instrumentalities shown. In the
drawings:
[0010] FIG. 1A shows a perspective view of an exemplary chamber
into which the filtration medium may be disposed to form a reactor
module;
[0011] FIG. 1B shows a cutaway longitudinal cross-section (section
A-A) of an exemplary reactor module;
[0012] FIG. 1C shows a perspective view of the module of 1A;
[0013] FIG. 2 shows a perspective view of an exemplary device that
includes a lid and reactor module;
[0014] FIG. 3 shows a perspective view of a different exemplary
device that includes a lid and a reactor module;
[0015] FIGS. 4A and 4B are schematic drawings illustrating the
winding or rolling of the mat around a hypothetical axis X-X;
[0016] FIG. 5 is a schematic drawing of several exemplary
convolution profiles for the non-planar surfaces of the mat and
well as plan-view examples of the placement of the convolutions on
the mat;
[0017] FIG. 6 is a perspective cut-away view of a device including
a reactor module that has the filter media arranged in a vertical
stacked configuration;
[0018] FIG. 7 (including FIGS. 7A and 7B) are graphs showing
H.sub.2S removal performance of a device of the invention at a 7
second residence time; and
[0019] FIG. 8 is a chart showing odor removal as compared to
residence time of a gas filtering device of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0020] The invention provides a filtration medium that can be used
to filter various liquid or gas materials. The filtration medium
may be inoculated with a biomass (most often primarily bacterial or
fungal (yeast) in nature; often a specific strain or mixture of
strains) that oxidizes or breaks down compounds in the gas or
liquid as it passes across the medium. The filtration media,
modules, and devices of the invention were developed to emphasize
performance of the filtration activity, including enhancement of
mass transfer (and therefore enhancement of filtration/oxidation
efficiency) and improvement of the adherence of microorganisms to
the media (providing increased number of microorganisms per unit
volume of media) as well as enhance the "life expectancy" of the
filtration medium itself, allowing for longer use before
replacement or maintenance of the filtration medium (necessitated,
for example, by collapse of mat material or clogging of mat with
biomass that has overproliferated) as compared to conventional
biological filtration mediums and/or modules.
[0021] The invention includes a filtration medium for the
purification or filtration of a liquid or a gas material, such as
wastewater, or reduction and elimination of odorous compounds in
water, gas or other emissions. The filtration medium includes a mat
that has a first surface and second surface and may be of any size
or format. In general, it may be desirable that the mat has a
substantially rectangular prism format; however, depending on the
end use and the specifics of the module or device into which it is
to be fitted, the size, shape, and format may be varied. In an
embodiment, the mat has thickness (i.e., length of Z axis of the
mat) of about 1/4 inches to about 4 inches, alternatively, about
3/4 inches to about 3 inches, or about 1 inch to about 2 inches in
thickness. In most applications the mat may be 1 inch thick or
greater.
[0022] As explained above, the length and width of the mat may
vary, but in most circumstances it may be preferable that the
length dimension of the mat is greater than the width dimension.
For example, the length dimension of the mat may be about 2 to
about 35 times greater than the width dimension or about 400 to
about 750 times greater than the width dimension. In some
embodiments, the mat may be any shape, including plan view polygon
(irregular or regular), circle, rectangle (including square), oval,
ellipse, or triangle. The format of the mat will vary depending on
the format of the reactor chamber that is selected.
[0023] The mat or mats used may be unitary or may be formed of two
or more sections of mat pieces together to form the desired
geometry. The sections may be attached to one another in any
manner, such as, for example, by glue, staples, they may be sewed
together or joined by heat fusion or heat seaming.
[0024] In an embodiment, the mat has a first surface and a second
surface, at least one of which is non-planar, wholly or in part. By
non-planar, it is meant that the surface, when viewed from the side
(i.e., as a profile) is not flat, but rather is convoluted and
exhibits surfaces terminating in at least two different planes in
space (the "peak" and the "valley" points), thereby expanding the
surface area of the mat available for bacterial (biomass)
adherence. The structures that provide the non-planar
characteristics are described by their "convolution profiles" as
discussed below.
[0025] In some embodiments, the mat may have each side with a
non-planar surface. The mat may be multilayered; for example it may
have 2 to 95 layers. As an example, the mat may consist of three or
more layers, wherein one or both of the outer layer(s) had a
non-planar surface (i.e., bears a convolution profile as noted
above).
[0026] At least one of the mat's surfaces has a non-continuous
convolution profile, that is, when viewed in cross section the
surface is substantially non-planar and such characteristic is
provided to the surface by convolutions that are arranged so that,
when sequential cross sections of the mat are viewed, the "peak"
and "valley" of the first cross section are located along the mat
in a different place than the "peak" and "valley" of the subsequent
cross section. This non-uniform placement of the convolutions
provides turbulence to the material being passed through the
filter. This differs from a foam mat having uniform corrugations,
that is a profile such that when sequential cross sections of such
a mat are viewed, they are substantially identical in relative
placement of the "peak" and the "valley" of the convolutions.
[0027] The surface convolutions may take the form of random
convolutions, ordered or patterned convolutions or any combination
of these. For example, with reference to FIG. 5, the convolution
profile of the surface(s) may be an egg crate profile, a sine wave
profile (such as for example, a short dine wave profile), a
rectangular profile, a zig-zag rectangular profile, a chevron
profile, a projecting villi (fingerlike projections) profile, a
compound villi, a tractor wheel profile, or a V-shaped profile. In
an embodiment, each of the first and the second surfaces of the mat
are non-planar, and may have the same or different convolution
profiles. In some embodiments, it may be preferred that the
selected profile has a peak-to-valley dimension of about 0.1 inch
to about 2 inches or about 0.5 inches to about 1.5 inches.
[0028] The surface convolutions may be placed or spaced on the
surface(s) of the mat (51) in any manner to create the profiles
discussed above. For example, as shown in FIG. 5, zig-zag or
wave-like patterns may be placed longitudinally in an evenly spaced
manner on the mat surface. Alternatively, the placement of the
convolution (as viewed in plan view) may be random or ordered. See,
FIG. 5 for non-limiting examples. In an embodiment, it may be
preferred that the convoluted surfaces are arranged so that the
non-uniform channels that are created are oriented to face the path
of the flow stream of the gas or liquid, although other
arrangements may be used.
[0029] The mat may comprise a foamed resin. The resin may be any
known or developed in the art that permits at least a minimal level
of bacterial adhesion. Thermoplastic resins may be preferred. In
some embodiments, the resin may be, for example, a phenolic resin,
a urethane resin, a polyurethane resin, a polyolefin, a nylon, a
polystyrene, polypropylene, polyethylene, polyether, polyester
and/or copolymer and derivatives of such polymers. The foamed resin
may be a reticulated or open cell foamed resin.
[0030] In some embodiments, it may be preferred that the foamed
resin is a polyurethane, an ester polyurethane, or an ether
polyurethane. Such foamed resins may be prepared by any means known
in the art. As an example, if the selected foamed resin is an ether
polyurethane foam, it may be made by, for example, by first forming
a cellular polyurethane foam that has a network of a least some
strands and at least some cell windows by mixing together
foam-forming compounds.
[0031] As is known to a person of skill in the art, the recipes for
polyurethane foam are expressed in terms of parts by weight per 100
parts of polyol. Thus, for example, for each 100 parts by weight of
a polyether polyol, the foam formulation according to the invention
includes: about 20.0 to about 60.0 parts by weight of an
isocyanate; about 1.5 to about 5.0 parts of a blowing agent, such
as water; about 0.20 to about 4.0 parts of a blow catalyst; about
0.0 to about 1.0 parts of a gel catalyst, and about 1.0 to about
3.0 parts of stabilizing surfactant, such as a silicone surfactant.
Other additives such as dyes, pigments, colorants, crosslinking
additives may also be incorporated into the foam formulation. After
the foam forming components have been mixed together, the foam is
permitted to rise and cure, preferably under atmospheric
temperature and pressure. The resulting foam has pore sizes
preferably in the range of about 8 to about 50 pores per linear
inch. The foam is further reticulated to remove any cell windows.
This process renders the foam with minimum resistance to fluid
flow. Reticulation is carried out by melting the windows by, for
example, a high temperature flame front to heat the cell windows or
walls to above the melting point of the polymer. Thus, by carefully
regulating the conditions under which this process is carried out,
the cell windows can be melted without adversely affecting or
melting the skeletal strands. The resulting foam will permit air
flows through the foam in a range of about 10 to about 50 cubic
feet per minute when measured through a 2 inch by 2 inch by 1 inch
foam sample.
[0032] Regardless of the type of foamed resin selected, the
selected material or materials may be substantially hydrophobic or
substantially hydrophilic, depending on the specific end
application of the mat and the desired level of bacterial adherence
necessary or desired. The material may be selected for its inherent
capacity to promote the growth of certain desirable bacterial
strains and/or retard the growth of other, less desirable
microorganisms, depending on the end application for the media. In
some embodiments, it is desirable that the materials selected are
suitable for maintaining a bacterial population so that, in
practice, at least 90%, at least 80%, at least 70%, or at least 60%
of the volume of filter medium is capable of supporting biomass,
thereby improving the number of microorganisms per unit volume and,
consequently, the efficiency per unit volume of the system.
[0033] In some embodiments where the filtered material is a gas, it
may be preferred that the material selected has a porosity of at
least about 99%, at least about 95%, at least about 90%, or at
least about 85%, to facilitate permeation of the gas phase to the
bacterial population.
[0034] Additionally, the mat may be coated with a material that
enhances bacterial attachment (and/or selectively promotes or
retards growth of specific microorganism) and/or such additives may
be mixed into the foamed resin material prior to cure. For example,
the foamed resin may contain an anti-mycotic or a differentially
selective antibacterial compound. The foamed resin may be coated
with any substance to alter or enhance desirable properties.
Suitable coatings may include acrylic polymer and/or acrylic
copolymers and latex emulsions.
[0035] In an embodiment, the mat of the filtration medium is
configured into a cylindrical format (33). With reference to FIG.
4A and 4B, this may be accomplished by rolling or winding the mat
(35) around a hypothetical winding axis X-X (29) so that the first
surface (25) contacts the second surface at a contact point (37).
Such contact between the surfaces may be continuous or
discontinuous contact. In an embodiment that may be preferred, at
least the first surface (25) is non-planar and bears projecting
convolutions, and the mat (35) is wound around the hypothetical
axis X-X (29) such that the projecting convolutions of the first
surface (25) are present at the exterior (or the interior, if
desired) of the concentric layers created by winding.
[0036] The winding tension applied will vary depending on the
material used, the type of convolutions, the end application and
other factors. However, in an embodiment, it may be desirable to
have a winding tension of about 1 to about 40 lbs per foam width
(ft) or about 2 to about 20 lbs per foam width (ft). In an
embodiment, the winding tension may be about 4 lbs/ft. The
modification of winding tension allows for adjustment in turbulence
created by the medium and to which the filtered material is
subjected as it passes though the medium.
[0037] In an embodiment, the mat is rolled with sufficient winding
tension such that contact of at least a portion of first surface
(25) to the second surface is made. If too much space is permitted
between the layers of the rolled cylindrical format (33), the
liquid or gas material may pass through the medium at too high a
rate to enable mass transfer at optimum efficiency. In an
embodiment where the filtration medium is used to remove certain
odorous compounds from air, it may be desirable to ensure that the
first surface and the second surface of the mat are substantially
in continuous contact when the mat is rolled in cylindrical format.
Preferably, the mat is wound in a manner that avoids formation of
substantially any straight line or direct channels through the
filter medium.
[0038] In an alternative configuration, the mat used may be of a
polygon geometry (such as a rectangular) format. Two or more mats
of substantially similar dimensions may be arranged together in a
vertical stack, as shown for example in FIG. 6. In this
arrangement, each surface of each mat is in physical contact with
the surface of the adjacent mat. The degree of contact of the mat
surfaces may be modulated by addition or lessening of a horizontal
compressive force applied to the mats, that is a compressive force
applied in the direction of an axis that is substantially
horizontal to the vertical axis of the stack. This force may be
applied, for example, by wiring or binding the vertical stack
together prior to insertion in a chamber, or may be applied by the
sidewalls, once the individual loose mats are assembled within the
chamber to form a reactor. By modulating the degree of contact
between the mat surfaces, the amount and/or flow rate of gas or
liquid through the medium can be optimized in each reactor
regardless of any other factors, such as mat thickness, size and
shapes of convolutions, size of reactor, etc.
[0039] The selected foamed resin used for the mat may have one or
more mechanical characteristics that provide structural support for
the mat during the filtration process once it is loaded with
biomass and fluid weight. In an embodiment, the foamed resin has at
least one mechanical characteristic chosen from a density of about
1 lbs/ft.sup.3 to about 3 lbs/ft.sup.3, alternatively, about 1.2
lbs/ft.sup.3 to about 2.5 lbs/ft.sup.3, or about 1.8
lbs/ft.sup.3.
[0040] Additionally or alternatively, it may be preferable that the
foamed resin from which the mat is made of a moderate to high
firmness. Firmness may be quantified by several methods/protocols
in the art, including determination of a given material's
indentation load deflection. Indentation load deflection (ILD) is
the force required to deflect the foam 25% (by volume) in pounds
(lbs). ILD is a well-known method of analysis and may be carried
out, for example, as directed in ASTM D3574-95, the contents of
which are incorporated herein by reference.
[0041] In an embodiment of the invention, one of the mechanical
characteristics of the foamed resin is an indentation load
deflection of about 35 lbs to about 150 lbs, about 75 lbs to about
120 lbs, or about 85 lbs to about 105 lbs. In may be suitable for
the foamed resin to exhibit both a higher density and a greater
firmness (i.e., within the parameters noted above), although the
presence of only one of these mechanical characteristics may be
present if the mat has sufficient mechanical strength to bear the
load of biomass and/or added liquid in the specific application
into which is it placed.
[0042] The mechanical characteristics of density and/or ILD may be
uniform throughout the foamed resin of the mat, or the resin may be
formulated or assembled such that the mechanical characteristic(s)
vary from area to area of the mat. For example, if the mat is in
the form of a substantially rectangular prism, it may be desirable
that the mechanical characteristic(s) of the foamed resin is
present as a decreasing or increasing gradient along the X-axis of
the prism, i.e., a hypothetical geometric axis initiating at a
point on the first surface and terminating at a point on the second
surface. (For purposes of clarity, it is noted that this geometric
axis is an axis of the mat itself and is therefore different that
the winding axis described above). As an example, the ILD of the
foamed resin may be about 100 lbs. at the first surface, then
decreases along the geometric X axis and may be about 25 lbs. at
the second surface, or the pore size of the foamed resin may be
about 4 to about 8 ppi at the first surface, the decreases along
the geometric X axis to be about 25 to about 35 ppi at the second
surface. Alternatively, the mat may include of two or more discrete
layers of foamed resins, each of which exhibits a different
magnitude of the selected mechanical characteristic. In such
configuration, it is preferred that the layer or portion of the mat
that forms the exteriormost (or the interiormost) region of the
cylindrical format is the layer or portion having the greater ILD
and/or density.
[0043] The foamed resins may exhibit other mechanical or chemical
properties. The nominal pore size of the foamed resin may vary; it
may be dictated by the specific end application or desired use. In
an embodiment, foamed resin has a nominal pore size of about 5
pores per liner inch (ppi) to about 70 ppi, about 7 to about 35 ppi
or about 10 to about 25 ppi.
[0044] Nominal distribution of pores within foamed resin may also
be varied. However, it may be preferred that pore distribution is
about 5 to about 70, alternatively, about 10 to about 40.
[0045] The foamed resin of the mat may be prepared of a neat resin.
Alternatively, it may be desirable to include various additives in
the resin to improve or modify performance, durability, water
sheddability, handling and other properties. For example, it may be
desirable to include clays, UV absorbers or protectants,
antimycotic agents, antibacterial components (for example, if
selective for specific types of undesirable bacteria), colorants,
deodorizers, fragrances, crafted polyols and combinations
thereof.
[0046] The invention also includes a device for the filtration of a
liquid or gas material. The device may include one or more reactor
modules. The reactor modules include a filtration medium (as
described herein). In an embodiment, the reactor module includes at
least one chamber. It may be any configuration, such as square,
polygonal or rectangle or circular in cross-section.
[0047] A given device of the invention may include one or more
reactor modules that contain the filtration media discussed above
and, optionally, a lid or cover. Within a device, each reactor
module may be identical (that is same type and structure of foam
and/or biomass). Alternatively, each reactor module may be targeted
to remove or oxidize a particular contaminant and therefore
necessarily contain a structurally different mat and/or contain a
mat that has been inoculated with a specific type of microorganism
that is know to reduce the targeted contaminant. The devices may
also include other features that aid in the efficiency of the
process, such as baffles to facilitate the even distribution of gas
or liquid through the device; spray nozzles situated to permit
moistening of the media and/or delivery of other substances to the
media; and/or collection or elimination systems.
[0048] Referencing FIGS. 1A, 1B, 1C, 2 and 3, the invention also
includes a device (23) for the filtration of a liquid and/or a gas
material. The device (23) may include one or more reactor modules
(13) and a lid (39). In an embodiment, the reactor module (13)
includes the filtration medium (11), in any variation as described
above, and a chamber (1). The chamber (1) may be substantially
cylindrical (i.e., of a substantially circular cross section when
viewed in the Y-Z plane). The chamber includes one or more sides
(7), a top (5) and a bottom (3). The chamber (1) includes a base
(9) that extends radially from the interior side(s) (7) of the
chamber (1) towards the center of the chamber (1). The base (9) may
be made of any suitable material or combination of materials,
including metal, metal that is coated or encased with high density
polyethylene, polypropylene or other polymer, polymer, fiberglass
reinforced polymers (such as polyesters, nylons, isopolyesters,
polyethylenes, isophthalic resins, orthothalic resins, vinyl
esters, epoxies, phenolic resins, and polypropylenes) and/or
textile and may be a size corresponding substantially to the
diameter of the chamber (3) or it may be a fraction of the size,
e.g., it may be "donut type" configuration, a base with cut outs, a
series of prong or bars and the like. The reactor chamber (3)
and/or the lid (39) may also include one or more ports (15, 19, 21)
for conveying the liquid or gas material in and out of the reactor
module. Depending on the phase of the material to be filtered (gas
or liquid) the ports will serve different purposes. If a gaseous
material is filtered, the inlet port(s) may be located beneath the
filtration medium at the base of the chamber and the outlet port(s)
may be located above at least a portion of the filtration medium in
the upper portion(s) of the chamber or the lid. The converse
arrangement may be utilized if a liquid material, such as
wastewater, is filtered.
[0049] In some embodiments, the modules may contain one or more
mediums (for example, layer within a chamber). Such media may be
the same or may be different. For example, at least one medium may
be a medium of the invention and the other(s) may be of another
type of medium, such as, for example, charcoal, carbon, wood chips,
compost, fiberglass, paper, silica, and/or clay. Similarly, the
device may include one or more modules, each modules having a
different medium or set of media.
[0050] In an embodiment, the base (9) is in the form of a grate,
support beams, posts, wire shelf or combinations of these. The
selected filtration medium (11) is disposed within the chamber (3)
such that the winding axis (29) of the mat (35) is substantially
parallel to the sides of the chamber (3) and the filtration medium
rests within the chamber (3) on the base (9). Optionally, a spacer
may be placed between the base (9) and the filtration medium (11),
and/or between any adjacently stacked mediums. Such spacer may be
adapted to promote even distribution of the material undergoing
filtration through the medium and/or to create turbulence in the
material.
[0051] Also included within the scope of the invention are methods
of filtering a gas or liquid material. Such methods include
applying a gas or liquid material to the filtration medium
described above, preferably when such medium is disposed within the
device described above.
[0052] For example, if material to be filtered is a gas, foul air
enters the bottom of the chamber (1) through port (15) after which
it is equalized in the bottom portion of chamber (1) before it
flows at substantially equal upflow velocity through the cross
section of the filtration medium (11). While the air flows through
the filtration medium (11), the odorous and other compounds in the
air are transferred to the microorganisms that oxidize the
compounds to non-odorous compounds. The filtration media may be
separated to include an equalization layer between the filtration
media. While the air is flowing through the filtration medium (11),
potable or substantially clean wastewater effluent is sprayed on
top of the filtration medium (11) at uniform flow distribution. The
water is used to remove the microbial products of oxidation, dead
microorganisms, enhance mass transfer of compounds from air to
water and microorganisms, and keep the microorganisms moist to
allow for optimum growth. The water flow may be intermittent or
continuous. The chamber (1) is fitted with a roof (39) and the
filtered air exits the roof (39) through port (21).
[0053] Referencing FIG. 6, an embodiment is shown having at least
two mats arranged in a vertical stack (41) and disposed within a
rectangular chamber (43) having four walls (45, 47, 47', 49) and a
base (not visible). In some embodiments, the chamber (43) may
include multiple vertical stacks (41) that are separated by a
spacer between them. FIG. 6 shows an embodiment wherein the base
has a structure that supports the vertical stack (41) but permits
the filtrate (gas) to pass through. For example, the base may be a
grid structure. The module of FIG. 6 includes a gas inlet (53)
through which gas is passed into a plenum chamber (55), after which
it passed through the vertical stack. In the specific device of
FIG. 6, the gas subsequently passes through an additional reactor
module (57) that contains a filtration medium consisting of common
activated charcoal, carbon, activated alumina, wood chips, compost
or combination thereof.
[0054] The individual mats in the vertical stack of FIG. 6 each
bear a peak-and-valley convolution having a peak-to-valley
dimension of about 0.25 inches to about 0.75 inches. The side walls
47 and 47' of the chamber apply a compressive force of about 3
lb/ft to about 5 lb/ft on the vertical stack.
[0055] Referencing FIGS. 7 (7A and 7B) and 6, data is provided
showing the efficiency and dpr removal capabilities of the
invention. In FIG. 7A and B, the data shown is a result of air that
was blown through the reactor at 675 cfm (cubic feet per minute),
which resulted in an empty bed residence time of 7 s. The hydrogen
sulfide (H.sub.2S) concentration of the air entering the reactor
device and that of the air exiting the reactor through the exhaust
stack are measured with OdaLogs every 10 s. FIG. 7A and B shows the
inlet and outlet H.sub.2S concentration vs. time, as well as the
removal efficiency vs. time for the same data at 7 s empty bed
residence time.
[0056] It will be appreciated by those skilled in the art that
changes could be made to the embodiments described above without
departing from the broad inventive concept thereof. It is
understood, therefore, that this invention is not limited to the
particular embodiments disclosed, but it is intended to cover
modifications within the spirit and scope of the present invention
as defined by the appended claims.
* * * * *