U.S. patent application number 12/928232 was filed with the patent office on 2011-05-26 for processes for water and wastewater treatment, including stationary cloth media filtration.
This patent application is currently assigned to Aqua-Aerobic Systems, Inc.. Invention is credited to Peter G. Baumann, Paul A. Hughes, Lioyd W. Johnson, David Smith.
Application Number | 20110120960 12/928232 |
Document ID | / |
Family ID | 32654339 |
Filed Date | 2011-05-26 |
United States Patent
Application |
20110120960 |
Kind Code |
A1 |
Smith; David ; et
al. |
May 26, 2011 |
Processes for water and wastewater treatment, Including stationary
cloth media filtration
Abstract
The present invention relates to stationary cloth media
filtration systems and devices, as well as processes and devices
for uniform flow distribution and improved cloth media filter
backwashing.
Inventors: |
Smith; David; (Beloit,
WI) ; Hughes; Paul A.; (Clovis, CA) ; Johnson;
Lioyd W.; (Roscoe, IL) ; Baumann; Peter G.;
(Roscoe, IL) |
Assignee: |
Aqua-Aerobic Systems, Inc.
|
Family ID: |
32654339 |
Appl. No.: |
12/928232 |
Filed: |
December 7, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11005561 |
Dec 6, 2004 |
7871527 |
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12928232 |
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10329630 |
Dec 26, 2002 |
6858140 |
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11005561 |
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Current U.S.
Class: |
210/791 ;
210/411; 210/456 |
Current CPC
Class: |
B01D 35/301 20130101;
B01D 29/684 20130101; B01D 2201/44 20130101; B01D 29/39 20130101;
B01D 29/39 20130101; B01D 29/684 20130101 |
Class at
Publication: |
210/791 ;
210/456; 210/411 |
International
Class: |
B01D 29/68 20060101
B01D029/68; B01D 29/50 20060101 B01D029/50; C02F 1/00 20060101
C02F001/00 |
Claims
1.-7. (canceled)
8. A system for providing uniform flow distribution for filtering
water or wastewater influent flow to a filtration region,
comprising: at least one trapezoidally shaped influent plenum
having orifices to distribute an influent flow across the
filtration region; and, at least one trapezoidally shaped effluent
plenum having orifices to receive the filtered influent flow.
9. An improved backwash system for backwashing cloth filter media
attached to a frame, comprising: a backwash header; a backwash
shoe; and, a means on the frame to create a gap between the
backwash shoe and cloth filter media.
10. A method for filtering an influent of water or wastewater in a
treatment basin having side walls and a floor and discharging a
filtered influent, including the steps of: introducing water or
wastewater for filtering into a treatment basin; filtering the
influent by gravity such that the influent flows through a
plurality of cloth filter media separately supported on a plurality
of individual stationary and substantially hollow cloth media
support structures, each individual support structure having a
length with two opposing ends, a cross-sectional shape and at least
one end being an open end adjacent to a side wall of the treatment
basin and in fluid communication with an outlet of the treatment
basin and each individual support structure suspended above the
floor of the treatment basin and substantially surrounded by
influent and the length of each individual support structure
extending between opposing side walls of the treatment basin such
that opposing ends of each said individual support structure are
mounted to and are supported by opposing side walls of the
treatment basin; discharging the filtered influent through an
effluent plenum having a substantially hollow interior which is
formed by each said stationary cloth media support structure and
the cloth filter media separately associated with each support
structure; and periodically cleaning said cloth filter media using
a backwash shoe and a traveling bridge assembly.
11. The method of claim 10 including a control system.
12. The method of claim 10 wherein said filtered influent is
discharged from the treatment basin through said at least one open
end.
13. The method of claim 10 wherein the cloth media support
structure has a diamond shaped cross-section.
14. The method of claim 10 wherein the cloth media support
structure has a hexagonal shaped cross-section.
15. The method of claim 10 wherein the cloth media support
structure has a circular shaped cross-section.
16. The method of claim 10 wherein the cloth media support
structure has a triangular shaped cross-section.
17. The method of claim 10 wherein the cloth media support
structure has a flat cross-section.
18. The method of claim 10 wherein the cloth media support
structure has a square shaped cross-section.
19. The method of claim 10 wherein the cloth filter media is
multi-piece.
20. The method of claim 10 wherein the cloth media support
structure is completely submerged by the influent of water or
wastewater.
21. A method for filtering an influent of water or wastewater in a
treatment basin having side walls and a floor and discharging a
filtered influent, including the steps of: introducing water or
wastewater for filtering into a treatment basin; filtering the
influent by gravity such that the influent flows through a
plurality of cloth filter media in the form of a one piece sock
separately supported on a plurality of individual stationary and
substantially hollow cloth media support structures, each
individual support structure having a length, a cross-sectional
shape and two opposing ends, at least one end being an open end
which is adjacent to a side wall of the treatment basin and in
fluid communication with an outlet of the treatment basin and each
individual support structure suspended above the floor of the
treatment basin and each individual support structure extending
between opposing side walls of the treatment basin such that
opposing ends of each said support structure are mounted to and
supported by opposing side walls of the treatment basin;
discharging the filtered influent through an effluent plenum having
a substantially hollow interior which is formed by each said
stationary cloth media support structure and the cloth filter media
separately associated with each support structure; and periodically
cleaning said cloth filter media using a backwash shoe and a
traveling bridge assembly.
22. A method for filtering an influent of water or wastewater in a
treatment basin having side walls and a floor and discharging a
filtered influent, including the steps of: introducing water or
wastewater for filtering into the treatment basin; filtering the
influent by gravity such that said influent flows through cloth
filter media supported on a stationary cloth media support
structure having two opposing ends and forming an effluent plenum
having a hollow interior substantially surrounded on all sides by
said cloth filter media and said support structure extends between
the opposing ends of the side walls of the treatment basin and is
suspended above the floor of the treatment basin, the opposing ends
of the support structure are supported by and are attached to the
opposing side walls of the treatment basin; discharging the
filtered influent through said effluent plenum; and periodically
cleaning said cloth filter media using a backwash shoe and
traveling bridge assembly.
Description
[0001] This application is a divisional of application Ser. No.
11/005,561, filed on Dec. 6, 2004, which is a divisional of
application Ser. No. 10/329,630 filed on Dec. 26, 2002, which
issued as U.S. Pat. No. 6,858,140 on Feb. 22, 2005.
FIELD OF THE INVENTION
[0002] The present invention relates generally to water and
wastewater treatment processes. More particularly, the present
invention relates to stationary cloth media filtration systems and
devices, as well as processes and devices for uniform flow
distribution and backwashing.
BACKGROUND OF THE INVENTION
[0003] There are a variety of established water and wastewater
treatment systems. One type that has been in use for decades, in
one form or another, is granular media gravity filtration. Granular
media gravity filters, such as conventional deep bed sand filters,
are used to strain out particles from a wastewater stream.
Typically, wastewater is introduced into a sand filtration region
from an influent chamber through inlet ports. The influent flows by
gravity through the granular media filter, such as sand contained
by a porous plate, to an effluent chamber. The granular media
filter bed, which is typically divided into a series of adjacent
cells, is then periodically cleaned using a variety of backwash
procedures. See, for example, U.S. Pat. No. 4,152,265.
[0004] Another well known type of water and wastewater filtration
is rotating cloth media filtration, often referred to as disk or
drum filtration. In general, disk or drum filtration systems
include a tank having an inlet and outlet and a rotatable filter
frame positioned between the inlet and outlet. Cloth filter media
is stretched over large drums or disk-type frame sections of the
rotatable filter frame. During filtering, influent flows into the
tank and passes through the cloth filter media, depositing the
suspended solids on the filter media. The filtered effluent is then
discharged from the tank outlet. See, for example, U.S. Pat. Nos.
4,090,965 and 4,639,315. The cloth filter media is periodically
cleaned by a variety of procedures, including backwashing and/or
high pressure sprays. See, for example, U.S. Pat. Nos. 5,374,360,
5,876,612 and 6,090,298.
[0005] In the early 1970's, a stationary cloth media filtration
system was attempted in Europe. As shown schematically in FIG. 29,
it is believed that this system included a filtration basin with a
series of rectangular effluent chambers, each effluent chamber
sandwiched between a pair of rectangular influent chambers. The
vertical walls between influent chambers and the effluent chamber
had a series of openings or windows across which cloth media
screens were attached (FIG. 30). In operation, the wastewater to be
treated was introduced into the influent chambers through
subsurface gates. The influent was filtered by passing the flow
through the screened windows of the filtration walls into the
effluent chamber. From there, the filtered effluent flowed through
subsurface gates to be discharged. The screens of this system were
periodically cleaned by backwashing, which was accomplished by
pulling a backwash header vertically up against the cloth filter
media, using a submerged chain and sprocket arrangement.
[0006] This attempt at stationary cloth media filtration suffered
from a number of problems. For example, if one of the filter
screens failed, that whole section of the filtration system would
have to be shut down, i.e., 2 influent chambers and associated
effluent chamber. In addition, because of their design, the seals
around the filtration screens were prone to leaks or failure,
resulting in poor quality effluent. Similarly, since most of the
moving parts, such as the chain and sprocket system needed for
backwashing, were submerged, the chambers had to be dewatered
before maintenance could be conducted. In short, this attempt at a
cloth filtration system was very complicated and inefficient. It is
believed that the system was a failure and was abandoned. As a
result, the industry moved in the direction of rotating cloth media
filtration methods, as generally described above.
[0007] Rotating cloth media filtration systems require that the
cloth filter media be subject to periodic cleaning, such as by
backwashing and/or high pressure spray. Typical backwashing
includes a suction header and backwash shoe assembly which is
pressed directly against and pulled along the cloth filter media
surface. In operation, a vacuum is applied to the suction header,
pulling fluid through the cloth filter media and the backwash shoe
in a direction opposite the flow direction during filtering (see
FIG. 31). This reverse flow removes much of the accumulated solids
caught in and blocking the cloth filter media. Typically, the
suction header and shoe press directly against the cloth filter
media (including the area where the cloth media is pulled against
the frame assembly) in the conventional backwash arrangement (even
when backwashing is not being conducted), which may put the cloth
filter media under a preload. This may result in increased wear and
premature break-through of the cloth filter media.
[0008] Conventional rotating cloth media filtration also has some
inherent limitations. For example, the filtration area is limited
by the size of the disks/drums and/or tanks. Larger disks/drums
require deeper and larger tanks, increasing their construction
costs. The retrofit or construction of smaller tanks requires
smaller disks, which reduces the filtration surface area.
[0009] Regardless of the type of filtration media used, uneven flow
distribution over the volume of the filtration basin or region is a
potential problem. For example, uneven or non-uniform flow
distribution within the filtration basin or region often results in
sludge settling, particularly in areas of low turbulence. This
often results in the need for additional sludge removal equipment
or increased system down time. In addition, non-uniform flow
velocity across the filter may also result in increased sludge
settling.
[0010] Thus, while the conventional deep bed sand and rotating disk
filtration systems generally described above have been widely and
successfully used in a variety of applications, each of these
systems suffer from drawbacks inherent in or related to their size,
design and/or application.
SUMMARY OF THE INVENTION
[0011] The present inventions preserve the advantages of known
water and wastewater treatment filtration systems and devices and
provide new features, advantages and benefits over these systems.
In addition, the present inventions preserve the advantages of
known systems and devices that may be used and/or are associated
with these systems and provide new features, advantages and
benefits.
[0012] For example, the present inventions provide higher quality
effluent (even at high solids and hydraulic loading rates), lower
backwash rates and higher capacity for a given basin footprint,
when compared to conventional sand filters. They also eliminate
sand or other granular media, making backwashing faster and more
efficient. When compared to rotating disk-type or drum-type cloth
media filtration systems, the present inventions provide, among
other things, higher capacity while maintaining a comparably high
quality effluent, continuous filtration during the backwash cycle
and the elimination of the necessity for rotary disks and drums and
their associated hardware. The present invention also provides more
uniform flow distribution in the basin and over the filtration
media, regardless of the type of filtration media used. The present
inventions also improve the backwashing operation and reduce wear
and break-through of cloth filter media for a variety of types of
cloth media filtration.
[0013] In addition, the present inventions provide for effective
stationary cloth media filtration, using unique filter plates that
overcome the disadvantages of the previously attempted stationary
cloth media filtration. Uniform flow distribution and decreased
sludge settling, as well as improved backwashing procedures, are
also provided.
[0014] In a preferred embodiment of the present invention, a
stationary cloth media filtration system for treating a flow of
water or wastewater in a filtration basin is provided which
includes at least one influent plenum having metering slots to
distribute the influent flow across the bottom of the filter basin;
at least one effluent plenum sealed from the influent plenum to
discharge filtered flow from the system; a filtration region having
a series of filter plates which are in fluid communication with the
effluent plenums; and, a backwash assembly to periodically clean
the filter plates. Preferred embodiments may also include generally
trapezoidally shaped, influent and effluent plenums that are
complementary to one another and located along the bottom of the
filter basin. Moreover, filter plates may be fastened directly to
the plenums.
[0015] Also in a preferred embodiment of the present invention, a
method of treating water or wastewater in a filtration basin using
filter plates is provided. The method includes providing an
influent flow of water or wastewater to be treated to an influent
channel and uniformly distributing the influent flow along the
length of the bottom of the filter basin; distributing the influent
flow uniformly across the width of the bottom of the filter basin;
filtering the influent flow with the filter plates; discharging the
filtered effluent with a relatively constant flow velocity and
reduced head loss; and, periodically cleaning the filter plates
with suction.
[0016] The present inventions also provide a system for providing
uniform flow distribution for filtering a water or wastewater
influent flow in a filtration region with at least one
trapezoidally shaped influent plenum with orifices to distribute
the influent flow into the filtration region, and at least one
trapezoidally shaped effluent plenum having orifices to receive the
filtered effluent flow.
[0017] Another preferred embodiment of the present invention
provides an improved backwash system for backwashing cloth filter
media attached to a frame. This system includes a backwash header,
a backwash shoe and a means to create a gap between the backwash
shoe and the cloth filter media.
[0018] Accordingly, it is an object of the present invention to
provide processes and devices for stationary cloth media
filtration;
[0019] Another object of the present invention is to provide
processes and devices for stationary cloth media filtration that
may be retrofit into existing filtration basins or designed for new
installations;
[0020] An additional object of the present invention is to provide
processes and devices for stationary cloth media filtration that
provide the capability of continuous filtration during
backwashing;
[0021] A further object of the present invention is to provide
processes and devices for stationary cloth media filtration with
high quality effluent and the maintenance of high quality effluent
at high solids and high hydraulic loading rates;
[0022] Still another object of the present invention is to provide
processes and devices for stationary cloth media water and
wastewater filtration that eliminate the need for traditional
granular media;
[0023] Still an additional object of the present invention is to
provide processes and devices for stationary cloth media filtration
that may provide cost advantages over traditional granular media
filtration, including but not limited to, reduced site footprint
requirements, resulting in less land use, decreased concrete costs,
as well as reduced enclosure costs in colder climates, and/or
reduced operational, maintenance and manufacturing costs, such as
the ability to change components above the water, easy replacement
of cloth media filter membranes and the like;
[0024] Still a further object of the present invention is to
provide processes and devices for the uniform fluid flow
distribution into and/or over the volume of a filtration region or
filtration basin;
[0025] Still an additional object of the present invention is to
provide processes and devices for the maintenance of consistent
flow velocity in a filtration region or filtration basin;
[0026] Yet an additional object of the present invention is the
uniform distribution of flow in a filtration basin or filtration
region;
[0027] Yet another object of the present invention is to provide
processes and devices for distributing and/or collecting flow in a
filtration region or basin having increased turbulence at the lower
portion of the filtration region or filtration basin and/or reduced
amounts of sludge settlement or other solids and/or a reduced need
for dedicated sludge removal equipment;
[0028] Yet a further object of the present invention is to provide
processes and devices that effectuate uniform flow distribution
over the filtration region or basin using a combination of influent
and effluent channeling to control flow and distribution;
[0029] Still yet another object of the present invention is to
provide processes and devices for improved backwashing of cloth
filter media;
[0030] Still yet an additional object of the present invention is
to provide processes and devices for cloth filtration media
backwashing without a preload on the cloth filter media;
[0031] Still yet a further object of the present invention is to
provide processes and devices for cloth filter media backwashing,
including a stop to position the suction header and shoe away from
the cloth filter media;
[0032] Still yet a further object of the present invention is to
provide processes and devices for backwashing cloth filter media
that extend cloth filter media life by decreased wear rate;
and,
[0033] Still yet a further object of the present invention is to
provide water and wastewater filtration systems and devices that
include one or more of the above stated objects, features or
advantages, alone or in combination.
Definition of the Terms
[0034] The following terms which may be used in the various claims
of this patent are intended to have their broadest meaning
consistent with the requirements of law:
[0035] Cloth filter media: Any permeable cloth-like material,
including but not limited to natural or synthetic fiber or membrane
compositions.
[0036] Filtration basin: The overall area devoted to the filtration
process, which may typically be divided into various filtration
regions, and which may have associated chambers, channels and the
like.
[0037] Filtration region: The area or areas in a filtration basin
where water and wastewater filtering is conducted, for example, by
using stationary cloth filter media in accordance with the present
inventions.
[0038] Filter plate(s): The cloth media filter frame assembly,
including at least the side, top and bottom frame members, and
associated cloth filter media. It may optionally include other
components as well and the term may often be used interchangeably
with filter frame assembly herein.
[0039] Traveling bridge assembly: The structural and mechanical
assembly typically located above the filtration basin that carries
the components necessary to conduct the backwash and other
operations and which is able to traverse the effective length or
portion of the filtration region or filtration basin.
[0040] Where alternative meanings are possible, in either the
specification or claims, the broadest meaning is intended. All
words used in the claims are intended to be used in the normal,
customary usage of grammar and the English language.
BRIEF DESCRIPTION OF THE DRAWINGS
[0041] The above described objects, features and advantages, as
well as other features and advantages of the present inventions
will become apparent by reference to the specification and
drawings; wherein like reference numbers are used for like elements
among the several views, and in which:
[0042] FIG. 1 is a side perspective view of a typical configuration
of a filtration basin of the present invention having an exemplary
two filtration regions;
[0043] FIG. 1A is a top plan view of the typical arrangement of the
filtration basin of FIG. 1 of the present invention;
[0044] FIG. 1B is a bottom perspective view looking from below the
typical configuration of the present invention of FIG. 1;
[0045] FIG. 2 is a side cross-sectional schematic view of a typical
arrangement of a filtration region of a filtration basin of the
present invention having an effluent baffle as a way to control
water elevation in the system;
[0046] FIG. 2A is a side cross-sectional schematic view of a
typical arrangement of a filtration region in a filtration basin of
the present invention having an effluent slide gate as an
alternative way to control water elevation in the system;
[0047] FIG. 3 is a perspective view of portions of the filtration
region of the present invention showing the major overall
components thereof;
[0048] FIG. 4 is a top plan view o f a preferred embodiment of an
effluent plenum and associated filter frame support mounts of the
present invention;
[0049] FIG. 5 is a side plan view of the preferred effluent plenum
and filter frame support mounts of FIG. 4;
[0050] FIG. 6 is an end plan view of the effluent plenum and
associated filter frame support mounts of FIGS. 4 and 5, showing
the closed end of a preferred effluent plenum;
[0051] FIG. 6A is an end plan view of the effluent plenum of FIGS.
4 and 5, showing the influent or open end of a preferred effluent
plenum;
[0052] FIG. 7 is a perspective view of a preferred effluent plenum
and an alternative arrangement of the associated filter frame
support mounts of the present invention, also showing the effluent
end of a preferred effluent plenum;
[0053] FIG. 7A is a perspective view of a preferred and an
associated filter frame support mount, including a schematic view
of a filter plate engaged with the filter frame support mount;
[0054] FIG. 8 is a perspective view of a preferred effluent plenum
and an alternative arrangement of the associated filter frame
support mounts of the present invention showing the effluent end of
a preferred effluent plenum, the alternative arrangement of filter
frame mounts on the effluent plenum and including schematic view of
several of the filter frames engaged with their associated filter
frame supports;
[0055] FIG. 9 is a bottom perspective view of a pair of adjacent
effluent plenums looking up from below the representative plenums
and showing an influent plenum of the present invention formed from
the complimentary exterior of the adjacent effluent plenums;
[0056] FIG. 10 is a bottom perspective view of additional adjacent
effluent plenums of the present invention showing influent plenums
formed from the complimentary exterior of the adjacent effluent
plenums;
[0057] FIG. 11 is a front plan view of a typical filter frame
assembly and associated hardware of the present invention;
[0058] FIG. 12 is a side plan view of a typical filter frame
assembly and associated hardware of FIG. 11;
[0059] FIG. 13 is a top plan view of the filter frame assembly and
associated hardware of FIG. 11;
[0060] FIG. 14 is a top view of a filter frame support mount and a
filter frame pin retaining plate of the present invention;
[0061] FIG. 15 is a side view of the filter frame support mount of
FIG. 14;
[0062] FIG. 15A is an end view of the filter frame support mount
and filter frame retaining plate of FIG. 15;
[0063] FIG. 16 is a top view of a preferred pin retaining plate of
FIG. 14;
[0064] FIG. 16A is a side view of a preferred pin retaining plate
of FIG. 16;
[0065] FIG. 16B is an end side view of a preferred pin retaining
plate of FIG. 16;
[0066] FIG. 17 is a bottom perspective view of two mating filter
frame support mounts on adjacent effluent plenums, showing the open
end of the filter frame support mount for receiving a portion of
the pin retaining plate, and also showing components of a preferred
pin retaining bracket of the present invention
[0067] FIG. 17A is a top plan view of a preferred pin retaining
bracket of a filter frame assembly of the present invention;
[0068] FIG. 18 is a bottom view of the filter frame assembly
showing a preferred interface between the filter frame and effluent
plenum;
[0069] FIG. 18A is a side view of the filter frame assembly and a
preferred interface between the filter frame and effluent plenum of
FIG. 18;
[0070] FIG. 19 is a perspective view of the orientation of the pin
retaining plate of the filter frame support arm and a pin retaining
bracket on the filter frame assembly;
[0071] FIG. 20 is a perspective view of two adjacent filter frame
assemblies showing their alignment with two adjacent and
corresponding filter frame support mounts;
[0072] FIG. 21 is a side plan view of a spring loaded fastener of
the present invention used to secure the filter frame assembly to
the filter frame support mount;
[0073] FIG. 22 is a schematic view of the general configuration of
the motion imparting components of a typical traveling bridge
assembly of the present invention;
[0074] FIG. 23 is a perspective view of the general configuration
of a typical traveling bridge assembly of the present invention
shown in a first position;
[0075] FIG. 24 is a perspective view of the general configuration
of a typical traveling bridge assembly of the present invention
shown in a second position;
[0076] FIG. 25 is a side perspective view of selected components of
a typical traveling bridge assembly showing the overall backwash
system components of the present invention;
[0077] FIG. 26 is a side plan view of a backwash system of the
present invention applied to a filter frame assembly, including
cloth filter media, of the present invention;
[0078] FIG. 27 is a side perspective view of the backwash system
component of the present invention of FIG. 26;
[0079] FIG. 28 is a side schematic view of the backwash operation
of the present invention;
[0080] FIG. 29 is a schematic plan view of the general arrangement
of a prior art cloth media filtration system;
[0081] FIG. 30 is a schematic sectional view of a filtration wall
and windows of the prior art filtration system taken along line
30-30 of FIG. 29;
[0082] FIG. 31 is a schematic side view of a typical prior art
suction header and shoe for backwashing cloth filter media showing
direct contact between the suction header and cloth filter
media.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0083] Set forth below is a description of what is currently
believed to be the preferred embodiments or best representative
examples of the inventions claimed. Future and present alternatives
and modifications to the preferred embodiments are contemplated.
Any alternatives or modifications which make insubstantial changes
in function, purpose, structure, use or result are intended to be
covered by the claims of this patent.
[0084] The general layout of a typical configuration of one
embodiment of the present invention may be seen by reference to
FIGS. 1 and 1A. The present invention may be designed to fit into
the footprint of an existing filtration basin to replace, for
example, a granular media gravity filtration system. It may also be
designed for a completely new facility, or installed in a tank
arrangement similar to conventional disk filtration. Moreover, many
aspects of the present invention may be applicable to other water
and wastewater treatment methods.
[0085] The present invention includes a filtration basin 10,
divided into a variety of channels, chambers, regions and the like,
the walls creating each of which are typically constructed of
concrete or other suitable material, such as steel or stainless
steel, particularly in a tank setting. In the example shown in
FIGS. 1 and 1A, filtration basin 10 is divided into two cloth media
filtration regions A and B. Cloth media filtration regions A and B
are, in all aspects pertinent to the present inventions, identical
in structure and operation. It will be understood by those of
ordinary skill in the art that one (basin), two or any number of
filtration regions may be provided depending upon the requirements
of the particular application. For example, to create additional
cloth media filter regions, a diversion of the influent into each
of the desired regions and collection of the treated effluent out
of each of the filter regions will be required.
[0086] In a preferred embodiment, and particularly the retrofit of
an existing basin, the filtration basin 10 includes a bulk influent
chamber 12 that receives the initial flow of water or wastewater to
be treated. An influent channel 14 which feeds filtration region A,
and an influent channel 15 which feeds filtration region B, are
also provided. Influent channels 14 and 15 are responsible for
conveying the influent from the upstream process via the bulk
influent chamber 12 and distributing the influent along the entire
length of a cloth media filtration region. An influent weir 16 (see
e.g., FIGS. 2 and 3) may be provided along the length of each of
the influent channels 14 and 15 to enable the control, adjustment
and distribution of flow along the length of each of the filter
regions. In addition, an influent baffle 17 (see e.g., FIGS. 2, 2A
and 3) is provided along the length of a filter region to direct
the influent flow to the bottom of the filter region for uniform
flow distribution and filtration using stationary cloth media as
hereinafter described. It will be understood by those of skill in
the art that influent channels 14/15 may have a manual or an
automatic slide gate(s) (not shown) to permit, among other things,
water level control and filter isolation.
[0087] The filtration basin 10 also includes an effluent channel 18
that receives treated water or wastewater from filter region A,
effluent channel 19 that receives treated wastewater from filter
region B, and a bulk effluent chamber 11 that receives the treated
effluent from effluent channels 18 and 19. Prior to the treated
effluent reaching effluent channels 18 and 19, the effluent may be
subject to an effluent baffle 20 and an effluent weir 13, both of
which help control and distribute the flow as dictated by the
requirement of a particular application. The effluent is then
transferred to bulk effluent chamber 11 for discharge. In lieu of
effluent baffle 20, an automatically controlled slide gate 27 and
its associated components (not shown) may be positioned at the end
of effluent channel 18/19 which is used to control the water level
in and flow through the system (see FIG. 2A). When the system is
used in this configuration, the effluent plenums 24 flow directly
to the effluent channels 18/19. It will be understood by those of
skill in the art that a wide variety of methods and devices may be
used to control the system flow consistent with the present
inventions.
[0088] The remainder of the discussion of the present inventions
and preferred embodiments thereof that relate to stationary cloth
filter media filtration will be by reference to a single cloth
media filtration region, such as filter region A. The primary
components that are part of or associated with a particular
filtration region of the present invention may be seen by reference
to FIGS. 1B and 3, and include: an influent channel 14, influent
plenums 22, effluent plenums 24, filter frame assemblies 26, also
referred to as filter plates 26, an effluent channel 18 and a
backwash system assembly 21, which is part of a traveling bridge
assembly 23.
[0089] The structure and operation of influent plenums 22 and
effluent plenums 24 may be understood by reference to FIGS. 4
through 10. The preferred embodiments of the effluent 24 and
influent 22 plenums are shown and described, although other forms
may be utilized consistent with the present invention. It is the
combination of plenums 22/24 and their equivalents that provide
uniform distribution of the influent flow across the filtration
region, regardless of whether filtration is conducted according to
the stationary cloth media filtration aspects of the present
invention or other types of filtration systems. In its preferred
form, uniform flow distribution is achieved by the influent and
effluent channeling, which may include the control and distribution
of flow from a single source and which is collected through a
single source.
[0090] More specifically, in the preferred embodiments, each
effluent plenum 24 is a generally trapezoidal shaped chamber that
is sealed from the unfiltered influent flow and preferably
constructed from a non-corrosive material, including but not
limited to stainless steel. Each effluent plenum 24 includes a
solid bottom plate 30, two solid side plates 31 (only one is shown
in FIGS. 5, 6 and 7), and a top plate 32. Top plate 32 is provided
with a series of oblong holes 33 that receive the filtered flow as
hereinafter described. Aligned with each of the holes 33 is a
filter frame support mount 35. Filter frame support mount 35 is
affixed to the top of plate 32 of the effluent plenum 24 and
functions to mount the filter frame assembly 26 to the effluent
plenums 24, as well as helping to strengthen the structural
integrity of the effluent plenums 24. As shown, for example, in
FIG. 4, filter frame support mount 35 as well as the longitudinal
axis of the oblong holes 33 are aligned perpendicular to the
longitudinal axis of the effluent plenum 24. The filter plates 26
are then vertically mounted thereto as shown generally in FIGS. 7
and 8.
[0091] The preferred effluent plenums 24 have a closed end 34 and
an open end 36, the open end 36 forming the effluent end of
effluent plenum 24. Closed end 34, as well as bottom 30 and open
end 36, are also provided with a flange 38 or other means to
facilitate attachment and alignment of effluent plenum 24 to the
bottom and/or side structure of the filtration region. Effluent
plenum 24 is provided with an effluent flange 37, also to
facilitate attachment of the effluent plenums 24 to the bottom
and/or side structure of the filtration region. The effluent
plenums 24 are arranged side-by-side in columns along the width of
the bottom of the filtration region (see FIGS. 1A and 8-10).
Specifically, in a preferred embodiment of the present invention,
the longitudinal axis of effluent plenums 24 are aligned with the
width of the cloth media filtration region and their length
coincides with the width of the region (see e.g., FIGS. 1A and 3).
The open or effluent ends 36 are adjacent to and are in fluid
communication with the effluent channel 18 and the closed ends 34
are typically adjacent to the influent channel 14, where the
influent baffle 17 or other means directs the influent to the
bottom or lower portion of the system. As a result, the filter
plates 26 are aligned in rows spanning the length of the filtration
region which, as discussed herein, enables efficient backwashing
and the like using a traveling bridge assembly 23.
[0092] The influent plenums 22 are also trapezoidally shaped
chambers that are complementary to and formed by the side-by-side
effluent plenums 24. As shown in the drawings (see e.g., FIGS. 9
and 10), in a preferred form, influent plenums 22 are tapered
channels formed from the pathway created between the sides 31 of
effluent plenums 24, the bottom of the influent plenums 22 being
preferably formed from the bottom of the cloth media filtration
region or filtration basin (not shown). Influent plenum tops 73 may
also be provided (see FIGS. 1A and 8-10) and which tops 73 form
metering slots 60 as hereinafter described. The influent plenum
tops 73 may be formed by a plate extending co-planar to the top
surface 32 of the effluent plenum 24. It will be understood that
the influent plenums 22 may be formed from separate components like
the effluent plenums 24. However, this is not required, since only
the effluent plenums 24 must be impervious to unfiltered flow.
Similar to the formation of the influent plenums 22 from the
side-by-side arrangement of the effluent plenums 24 along the
bottom of the cloth media filtration region, a series of metering
slots 60 are formed in the influent plenum top 73 along the upper
portion of the influent plenums 22 as a result of the alignment and
spacing of the plates 73 which form the top of influent plenums 22
and metering slots 60.
[0093] With reference to FIGS. 6-8 and 14-15A, in a preferred
embodiment of the present invention, filter frame support mount 35
is a tubular, generally rectangular member. A pin retaining plate
50 extends laterally outward from one end and may be attached to
filter frame support mount 35 by welding or other well known means.
Pin retaining plate 50 includes a key slot 51 which is bored or cut
through plate 50. The underside of pin retaining plate 50 is
provided with a longitudinal pin lock groove 52. Pin lock groove 52
is perpendicular to a key way 53 of key slot 51. The end 59 of
filter frame support mount 35 opposite to the pin retaining plate
end 50 remains open in a preferred embodiment. These elements
function to mount the filter plate 26 to the effluent plenums
24.
[0094] The top 54 and bottom 55 surfaces in the central portion of
filter frame support mount 35 are removed or cut away (or filter
frame support mount 35 is simply assembled leaving an upwardly open
sleeve 57), leaving only side surfaces 56. As indicated, this forms
an upwardly facing open sleeve 57. Open sleeve 57 is slightly
larger than the oblong hole 33 on the top plate 32 of effluent
plenums 24, and is centered on filter frame support mount 35 so
that it aligns with elongated hole 33 of effluent plenum 24 when
the support mount 35 is welded or otherwise attached to the top
plate 32 of effluent plenums 24. When attached to the effluent
plenums 24 as described, the open sleeve 57 of filter frame support
mount 35 forms a filter plate/effluent plenum interface shown
generally as 58 (see FIG. 4). This interface 58 may be fitted with
gaskets or seals to keep the influent from entering the effluent
plenum 24 prior to filtration.
[0095] As indicated, the end of filter frame support mount 35
opposite the end with the pin retaining plate 50 remains open 59.
In this manner, when the effluent plenums 24 are arranged
longitudinally along the width of the bottom of the filtration
region, a portion of pin retaining plate 50 of one effluent plenum
24 is received within the opening of the corresponding filter frame
support mount 35 of the adjacent effluent plenum 24 (see FIGS. 17
and 19).
[0096] Moreover, as shown in FIG. 4, pin retaining plate 50 may be
located on alternate sides of the filter frame support mount 35.
Specifically, in a preferred embodiment, half of the adjacent
filter frame support mounts 35 may have the pin retaining plate 50
on one side and the remaining half of the filter frame support
mounts 35 may have the pin retaining plate 50 on the other side.
Similarly, the filter frame support mounts 35 on the adjacent
effluent plenum 24 will have their pin retaining plate 50 on the
opposite sides, so that the open ends 59 of filter frame support
mount 35 mates with pin retaining plate 50 as described above (see
e.g., FIGS. 4 and 9).
[0097] As referred to above, the openings or metering slots 60 of
the influent plenums 22 are formed from the influent plenum tops
73, as best shown in FIGS. 8, 9 and 10. In this manner, and in
conjunction with the taper shape of the influent plenums 22,
influent exiting through the metering slots 60 is uniformly
distributed within and across the width of the filtration region
via the influent baffle 17 and influent plenum 22. Moreover,
because of the taper of the trapezoidal influent plenums 22, even
flow velocity is maintained and there is no tendency for solids to
settle on the influent plenum 22 bottom.
[0098] The design and structure of filter plate 26 may best be seen
by reference to FIGS. 11-13 and 18-18A. As shown, each filter plate
or, more generally, filter frame assembly 26 is a generally
rectangular frame with a hollow center and consists of side members
41, top member 42 and bottom member 43. A handle or handles 44
attached to top member 42 may also be provided to aid installation,
maintenance and/or repair. The side 41, top 42 and bottom 43
members of filter plate 26 form a rectangular box-like structure,
the front and back faces 45 of which are fitted with a support
screen 46. Cloth filter media 47 (see e.g., FIG. 3) may be
stretched across and attached to the front and rear filter faces
45. However, in a preferred embodiment, cloth media 47 is stretched
around the whole filter frame assembly 26 which eliminates the risk
of unfiltered influent into the effluent plenums 24. Also included
are generally v-shaped (in cross-section) top and bottom tensioners
48. Similarly, the side members 41 are provided with side
tensioners 49. The support screens 46 function to help the cloth
filter media 47 from deforming to the hollow center of filter plate
26, and the tensioners 48 and 49 provide tension to the cloth
filter media 47 to form a taught diaphragm for filtering. In
addition, top and bottom tensioners 48 act as a rail along the
faces 45 of filter plate 26 to create a gap to protect the cloth
filter media 47 during backwash operations and to prevent
pre-loading as discussed herein. This adjustable or settable gap is
shown schematically in FIGS. 26-28.
[0099] The bottom frame member 43 includes an oblong hole 62 (see
FIG. 18) that is positioned and sized to communicate with oblong
hole 33 on the top 32 of effluent plenum 24. A collar 63 extends
downwardly from and is coincidental with oblong hole 62. Collar 63
is designed to fit within and create a water-tight seal with the
open sleeve 57 of filter frame support mount 35 and completes the
filter plate/effluent plenum interface 58. In this manner,
untreated influent passes through the cloth filter media 47, is
filtered and the filtered effluent passes through oblong hole 62 of
bottom frame member 43, into oblong hole 33 into effluent plenum
24, as hereinafter described in more detail. In this manner, there
is only one area of possible penetration of influent flow into the
effluent plenum 24.
[0100] In a preferred embodiment of the present invention, each
filter plate 26 is attached to the filter frame support mount 35,
and hence, in fluid communication with effluent plenum 24, through
the use of a single fastener. Specifically, collar 63 is provided
with a plate latch 64. Plate latch 64 is essentially a tab or other
similar member extending from one end of collar 63 that is designed
to fit under and mate with edge 65 of filter frame support mount 35
(e.g., FIGS. 14 and 15). As a result, plate latch 64 acts as a
hinge to restrain one end of collar 63 of filter plate 26.
[0101] At the end of the bottom member 43 of filter plate 26
opposite latch plate 64, a pin retaining bracket 66 is provided
(see FIGS. 14 and 15). Pin retaining bracket 66 includes a key slot
67 and a key way 68 that aligns and mates with key slot 51 and key
way 53 of pin retaining plate 50 of filter frame support member 35
(see FIGS. 17-17A and 19). Pin retaining bracket 66 is secured to
pin retaining plate 50 through the use of a spring loaded fastener
69. Specifically, in a preferred embodiment, spring loaded fastener
includes a pin 70 with a key 71 at one end, and a compressive
spring 72 at the other. Thus, in order to secure the pin retaining
bracket 66 to pin retaining plate 50, pin 70 is inserted into key
slot 67 and key slot 51 so that key 71 passes through key ways 53
and 68. The pin 70 is then rotated so that key 71 engages pin lock
groove 52, securing the bracket 66 and plate 50 together. In order
to ensure a watertight seal at the plenum/plate interface 58, a
closed cell foam gasket seal (not shown) or other suitable gasket
may be used. Similarly, each filter plate 26 may include an
alignment tab 61 on the end opposite the pin retaining bracket 66.
Alignment tab 61 serves to keep adjacent filter plates 26 in
alignment on adjacent filter frame support mount 35 of adjacent
effluent plenums 24 (see FIG. 17). Other forms of adjustment and
retention will be apparent to those of skill in the art.
[0102] Having described the majority of the principal components of
the present inventions, the typical operation may now be discussed.
Specifically, in operation of the preferred embodiment, influent is
introduced into bulk influent chamber 12 and is divided between
influent channels 14 and 15 (e.g., FIG. 1A). However, only one
filtration region (A) will be discussed. The influent flows over
influent weir 16 and is diverted via influent baffle 17 to the
bottom of the filtration region (see also FIGS. 2-3). The influent
flows up through metering slots 60 created by (or alternatively,
in) the influent tops 73. As a result of the shape of influent
plenum 22, the influent is uniformly distributed over the entire
width of the filtration region. The influent then flows through the
cloth media 47 of filter plate 26 and is filtered. The filtered
flow flows into the sealed effluent plenums 24 via the filter
plate/plenum interface 58 and is collected in effluent channel 18,
either through the use of an effluent baffle 20 arrangement or an
automatic slide gate 27 arrangement.
[0103] Since the cloth media 47 becomes clogged over time, it is
necessary to periodically backwash the cloth filter media 47. A
traveling bridge assembly 23 is used to house and carry the
necessary components for backwashing and other operations. In
general, traveling bridge assembly 23 travels along the length of a
filtration region (or filtration basin 10) from a first position
(FIG. 23) to a second position (FIG. 24), and back again. Traveling
bridge assembly 23 may include wheels 28 that roll along rails 25
on top of filtration basin 10. Alignment wheels 29 (see FIG. 22)
may also be included to help guide and align traveling bridge
assembly 23 during travel.
[0104] The backwash system 21 of the present invention may better
be seen by reference to FIGS. 25-28. In general, the backwash
system assembly includes suction headers 75 connected to a suction
pump 76. A backwash shoe 76 is positioned to ride along the cloth
filter media 47 on the front and back faces 45 of each of the
adjacent rows of filter plates 26. In a preferred embodiment of the
present invention, backwash shoe 76 rides along top and bottom
tensioners 48 of filter frame assembly 26, thereby producing a gap
40 between the cloth filter media 47. This reduces wear on the
cloth filter media 47 and eliminates preload and its associated
problems.
[0105] Thus, during a typical backwash operation, the backwash
shoes 76 are pulled along the longitudinal rows of filter plates 26
by traveling bridge assembly 23 and its associated backwash headers
75 of backwash assembly 21. In a preferred embodiment of the
present invention, only half of a row of filter plates is
backwashed in each direction of travel of the traveling bridge 23.
That is why, in a preferred embodiment, half of the pin retaining
plates 50 are on one side and half on the other side of the filter
frame support mount 35. Backwashing will also start and stop at the
same place as the traveling bridge assembly moves from its first to
second position and returns.
[0106] The above description is not intended to limit the meaning
of the words used in the following claims that define the
invention. Rather, it is contemplated that future modifications in
structure, function or result will exist that are not substantial
changes and that all such insubstantial changes in what is claimed
are intended to be covered by the claims. Thus, while preferred
embodiments of the present inventions have been illustrated and
described, it will be understood that changes and modifications can
be made without departing from the claimed invention. In addition,
although the term "claimed invention" is sometimes used herein in
the singular, it will be understood that there are a plurality of
inventions as described and claimed.
[0107] Various features of the present inventions are set forth in
the following claims.
* * * * *