Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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SETTLING BASIN INSERT
TECHNICAL FIELD
[0001] This relates to settling basins, and in particular, to devices and
methods for
controlling flow and quality of fluid, for example storm water, into a
settling basin.
BACKGROUND
[0002] Settling basins typically use sedimentation to remove suspended
solids from
fluid using gravity. Settling basins may be formed of a structure such as
concrete, or
an earthen structure, for example a settling pond.
[0003] Settling basins may collect inflowing fluid such as storm water or
waste
water through an inlet. lnflowing fluid may carry suspended solid particles
that may
include dirt, sand, litter, or other waste. As the inflowing fluid enters the
basin, particles
in the fluid are separated by gravity and particles settle to the bottom of
the basin to
form sediment. The fluid is retained in the basin for a settling time that
allows the
desired particle size to be separated. Smaller particles may require longer
settling time
or larger volume basins, as smaller particles have a smaller settling
velocity, defined
as the terminal velocity reached by a particle as it falls through a fluid.
[0004] Following settling, water may outflow from the settling basin at an
outlet or
overflow points.
[0005] Settling within the basin may be affected by turbulence in the
water.
Turbulence may be caused, for example, by wind, geometry of the basin, inlet
design
and outlet or overflow design.
[0006] High flow rate or fast-flowing inflowing fluid may agitate settled
sediment in
conventional settling basins, for example, in periods of increased flow rate
or volume
of inflowing fluid, a storm event or periods of heavy rainfall intensity.
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[0007] Using traditional maintenance methods, an entire settling basin may
be
drained to allow sediment that has settled on the bottom of the basin to be
removed
manually or using a machine such as a mechanical loader or crane, or a vacuum
truck.
[0008] Accordingly, there is a need for improved collection and removal of
sediment
collected from inflowing fluid.
SUMMARY
[0009] According to an aspect, there is provided a settling basin insert
for
controlling fluid flow into a settling basin, the settling basin insert
comprising: a first
side wall and a second side wall in opposition, and a top surface extending
between
the first side wall and the second side wall, the first side wall, the second
side wall and
the top surface defining a sump extending from a head to an end; and a
plurality of
fluid apertures extending through the top surface to permit fluid to
communicate with
the sump therethrough and an access aperture in the top surface to permit a
vacuum
hose to pass into the sump; wherein the first side wall is taller than the
second side
wall, and the first side wall and the second side wall each define a guide
wall
extending above the top surface, and the second side wall is configured to be
adjacent
the settling basin.
[0010] According to another aspect, there is provided a method of
controlling fluid
flow into a settling basin, comprising: directing fluid towards a head of a
settling basin
insert at approximately a permanent water level of the settling basin;
directing fluid
over flow dispersion protrusions, thereby decelerating the fluid; diverting
fluid from
passing into the settling basin by directing fluid along the settling basin
insert by a first
guide wall adjacent the settling basin and extending above approximately the
permanent water level of the settling basin, and an opposing second guide wall
adjacent land and extending above approximately the permanent water level of
the
settling basin to a height greater than a height of the first guide wall; and
directing fluid
through apertures along a surface of the settling basin insert to further
decelerate the
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fluid for settling of sediment in the settling basin insert.
[0011] Other features will become apparent from the drawings in conjunction
with
the following description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] In the figures which illustrate example embodiments,
[0013] FIG. 1 is a diagram of fluid flow in a settling pond;
[0014] FIG. 2 is a top plan view of an example settling basin insert,
installed
adjacent to a settling pond;
[0015] FIG. 3 is a cross-sectional view of the settling basin insert of
FIG. 2 along
lines III-Ill;
[0016] FIG. 4 is a front perspective view of a section of the settling
basin insert of
FIG. 2;
[0017] FIG. 5 is a perspective view of the settling basin insert section of
FIG. 4,
rotated 45 degrees;
[0018] FIG. 6 is a top plan view of the settling basin insert section of
FIG. 4;
[0019] FIG. 7 is a cross-sectional view of the settling basin insert
section of FIG. 4
along lines VII-VII;
[0020] FIG. 8 is a rear elevation view of the settling basin insert section
of FIG. 4;
[0021] FIG. 9 is a partial cross-section view of an access aperture,
according to an
embodiment;
[0022] FIG. 10 is a rear elevation view of an end plug of the settling
basin insert of
FIGS. 2 and 3;
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[0023] FIG. 11 is a cross-sectional view of a first fluid flow path along
the settling
basin insert of FIG. 2 along lines III-Ill and lines X-X;
[0024] FIG. 12 is a cross-sectional view of a second fluid flow path along
the
settling basin insert of FIG. 2 along lines and lines X-X; and
[0025] FIG. 13 is a top plan view of a settling basin insert, according to
an
embodiment.
DETAILED DESCRIPTION
[0026] FIG. 1 depicts a typical settling basin, such as a settling pond 50.
Settling
pond 50 is formed of an earthen structure having slopes descending from a
shoreline
at ground level to a bottom. Inflowing fluid /, such as waste water, may flow
through
inlet 40 into settling pond 50. Fluid / may carry solid particles, for example
dirt, sand,
litter, or other waste. As used herein, unless otherwise specified, references
to "fluid"
or "fluid flow" may also include any entrained solid particles. Fluid
accumulates in pool
P in settling pond 50 until the level of pool P reaches outlet 70. Thereafter,
further fluid
flowing into settling pond 50 causes fluid to be displaced out of settling
pond 50
through outlet 70, for example, into further components of a water treatment
system.
[0027] Fluid generally resides in pool P in settling pond 50 until it is
displaced
through outlet 70 or until it evaporates. Thus, fluid typically resides in P
for a period of
time which may be proportional to the rate at which fluid flows into settling
pond 50.
When fluid I flows slowly or intermittently, pool P may be relatively still,
which may
allow sediment S to settle to the bottom of settling pond 50, rather than
being carried
with outflowing fluid. Accumulated sediment S may periodically be removed
(e.g.
manually or using a machine) and disposed of. Removal of sediment S from the
bottom of settling pond 50 may require drainage of the fluid in pool P from
pond 50.
[0028] Events such as periods of increased volume of inflowing fluid, a
storm event
or periods of heavy rainfall intensity may cause inflowing fluid Ito rush into
settling
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pond 50 at a high velocity or flow rate. In some cases, incoming fluid at high
flow rate
or velocity may agitate pool P and promote mixing of previously-settled
sediment S,
which may ultimately lead to sediment being carried out of pond 50. Moreover,
the flow
of incoming fluid may exit more quickly through outlet 70, rather than
residing in pond
50 for a significant period of time. Accordingly, incoming solid particles may
not have
an opportunity to settle and may simply be carried out of pond 50.
[0029] Accordingly, deceleration of fluid flow and diversion of fast-
flowing fluid to a
preliminary location such as a settling basin insert 10, as illustrated in
FIG. 2, before it
enters a settling basin such as a settling pond 50' may tend to promote
settling and
retention of at least some sediment in settling basin insert 10 before fluid
enters pond
50', allowing for planned removal and disposal thereof.
[0030] FIG. 2 is a top plan view of settling basin insert 10 installed
adjacent to, or
near an edge of, settling pond 50' such that settling basin insert 10 abuts
settling pond
50' on one side and abuts land, for example an access road 60, on the opposing
side.
FIG. 3 illustrates a cross-sectional view of settling basin insert 10 along
lines of
FIG. 2.
[0031] Settling basin insert 10 has a head 20 and an end 22, and may be
formed in
a straight line, as shown in FIGS. 2 and 3, or bend at various points, as
shown for
example in FIG. 13, depicting a settling basin insert 10' having a bend of 135
degrees.
[0032] Settling basin insert 10 may be, for example, between 3 m and 60 m
in
length from head 20 to end 22.
[0033] An inlet 40' directs inflowing fluid to settling basin insert 10.
Inlet 40' may be
a cylindrical pipe with an opening generally circular in cross-section, as
depicted for
example in FIGS. 2 and 3. Inlet 40', as depicted in FIGS. 2 and 3, may run
horizontally
parallel to settling basin insert 10 and deposit inflowing fluid at head 20 of
settling
basin insert 10 above the level of a sump 38 of settling basin insert 10,
discussed in
further detail below. The size of the opening of inlet 40' through which fluid
flows into
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settling basin insert 10 may vary, as well as the angle from horizontal of
inlet 40', to
affect the flow rate and direction of inflowing fluid to settling basin insert
10, and the
location at which inflowing fluid enters settling basin insert 10. For
example, in some
embodiments, a larger or flanged opening of inlet 40' may allow for a larger
volume of
flow to exit inlet 40' to settling basin insert 10. In some embodiments, the
opening of
inlet 40' may be other shapes in cross-section, such as generally oval or
generally
rectangular. In some embodiments, a steeper angle of inlet 40' from horizontal
may
result in accelerated flow, and a shallower angle of inlet 40' may result in
decelerated
flow as inflowing fluid enters settling basin 10. In some embodiments, inlet
40' may
have a bend, for example between zero and 90 degrees, preferably 45 degrees,
upstream from where inlet 40' meets settling basin insert 10, which may
provide a
tortuous flow path to decelerate or divert fluid flow before reaching settling
basin insert
10. In some embodiments, inlet 40' may include protrusions to decelerate or
divert flow
before reaching settling basin insert 10.
[0034] An outlet for fluid displaced out of settling pond 50' is omitted
from FIG. 2.
[0035] Some or all fluid flowing into pond 50' may flow along settling
basin insert 10
before entering pond 50'. Settling basin insert 10 directs inflowing fluid
from inlet 40'
through a flow path to decelerate the flow and aid settling and retention of
sediment.
[0036] Settling basin insert 10 includes a first side wall, land-side wall
34, and a
second side wall, pond-side wall 36, and may include a base 32, as can be seen
in
FIGS. 4 to 8. FIGS. 4 to 8 also illustrate a settling basin insert section 11,
a number of
which can be placed along the length of settling basin insert 10, to define
settling basin
insert 10.
[0037] Settling basin insert 10 may be between 1200 mm and 3600 mm in
width,
from land-side wall 34 to pond-side wall 36.
[0038] Each of land-side wall 34 and pond-side wall 36 may intersect with
base 32
at a chamfered edge, as shown in FIGS. 4, 5 and 8, or at a right-angled edge
with one
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or both of land-side wall 34 and pond-side wall 36 intersecting base 32 at 90
degrees.
Land-side wall 34, pond-side wall 36 and base 32 may be formed, for example,
from
concrete, such as precast concrete box culverts, metal, fiberglass, wood or
plastic.
[0039] Along the length of settling basin insert 10, a top surface, for
example a
plurality of grates 12, are positioned over the open top between land-side
wall 34 and
pond-side wall 36, defining sump 38. Sump 38 may collect fluid and sediment
that
flows into settling basin insert 10, as discussed in further detail below.
Each settling
basin insert section 11 may have a corresponding grate 12.
[0040] Grate 12 has a head-side 120A, defined as a side of grate 12 that is
generally adjacent a position at which a fluid flow would first contact grate
12 as it
flows along settling basin insert 10, an end-side 120B, defined as the
opposing side of
grate 12, a land-side 120C generally adjacent land-side wall 34, a pond-side
1200
generally adjacent pond-side wall 36, and a centre portion 120E, generally mid-
way
between land-side 120C and pond-side 120D.
[0041] Grate 12 may be formed from concrete, for example, and as such,
grate 12
may be formed integrally with land-side wall 34 and pond-side wall 36 as
depicted in
FIGS. 4, 5 and 8. Grate 12 may be, for example, 3048 mm long, 2500 mm wide and
250 mm in height at its lowest height. Grate 12 may be chamfered and flange
downwardly on land-side 120C towards land-side wall 24, and flange downwardly
on
pond-side 120D toward pond-side wall 36, as depicted in FIGS. 4, 5 and 8. Such
chamfers may offer structural support to grate 12 and settling basin insert 10
as fluid
flows along and through grate 12 and settling basin insert 10.
[0042] In other embodiments, grate 12 may be formed of other materials, for
example, from metal, fiberglass, wood or plastic, and formed separately and
attached
to land-side wall 34 and pond-side wall 36. For example, grate 12 may be
formed of
concrete poured as one piece, with formations at the bottom of its haunches on
each
side to interlock with, for example, holes or slots present on the tops of
land-side wall
34 and pond-side wall 36, to attach grate 12 to land-side wall 34 and pond-
side wall
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36. In embodiments where one of grate 12, land-side wall 34, or pond-side wall
36 are
formed of concrete, an anchor, for example a drop-in anchor, may be used as an
attachment point for another of grate 12, land-side wall 34, or pond-side wall
36. Other
suitable attachment techniques would be understood by a person skilled in the
art.
[0043] Each grate 12 has fluid apertures 14 through which fluid can
communicate
and flow into sump 38, which also promotes deceleration of fluid flowing along
grates
12.
[0044] As depicted, fluid apertures 14 extend across grate 12 generally
perpendicular to land-side wall 34 and pond-side wall 36. However, in some
embodiments, fluid apertures 14 may vary in number, size, shape and
configuration on
grate 12 or another top surface, for example extending generally parallel to
land-side
wall 34 and pond-side wall 36, or vary in cross-sectional shape, including
generally
circular or generally rectangular. The number, size, shape and configuration
of fluid
apertures 14 on grate 12 may vary based on the width of the section of
settling basin
insert 10.
[0045] Placement and sizing of fluid apertures 14 within grates 12 may be
scaled
based on the size of settling basin insert 10 and its components and
conditions of
inflowing fluid.
[0046] For example, in a settling basin 10 having grates 12 that are 3048
mm long
and 2500 mm wide, fluid apertures 14 may be located between 200 mm and 400 mm
from the head-side 120A and end-side 120B of grate 12, preferably 200 mm from
head-side 120A and 400 mm from end-side 120B. Each fluid aperture 14 may be
between 50 mm and 300 mm wide, where the "width" of fluid aperture 14 extends
from
adjacent head-side 120A to towards end-side 120B, preferably 100 mm wide.
Fluid
apertures 14 may be separated by a distance between 200 mm to 400 mm apart,
preferably 300 mm apart. Each fluid aperture 14 may extend lengthwise across
grate
12 from land-side 120C to pond-side 120D with a length preferably between 300
mm
and 1500 mm. In some embodiments, a number of fluid apertures 14 may extend
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across grate 12 in two columns, a first column of fluid apertures 14 extending
from
land-side wall 34 towards centre portion 120E of grate 12, with a length, for
example,
of approximately 1500 mm. A number of fluid apertures 14 in the first column
may be
offset from land-side wall 34 by the presence of an access aperture 16,
discussed in
further detail below, and have a length, for example, of approximately 850 mm.
A
second column of fluid apertures 14 may extend from pond-side wall 36 towards
centre portion 120E of grate 12 and have a length, for example, of
approximately 1500
mm, as shown in FIGS. 2, 4, 5 and 6.
[0047] In other embodiments, fluid apertures 14 may extend across grate 12
from
land-side wall 34 to pond-side wall 36 with a length of approximately 3048 mm.
The
remaining fluid apertures 14 may extend lengthwise from pond-side 120D of
grate 12
towards land-side 120C of grate 12 to a point adjacent access aperture 16
having a
length of approximately 2400 mm.
[0048] The dimension ranges above are provided by way of example. In some
embodiments, placement and sizing of fluid apertures 14 may fall outside of
the ranges
provided above. The placement and sizing dimensions of fluid apertures 14
could be in
different ranges, depending, for example, on the scaling appropriate for the
inflowing
fluid. In some embodiments, the relative proportionality of fluid apertures 14
on grate
12 may remain consistent as grate 12, section 11, or settling basin insert 10
is scaled
smaller or larger, for example, depending on the flow rate and volume of
inflowing fluid
and the size of inlet 40'.
[0049] Each fluid aperture 14 may be angled through the body of grate 12 at
between 60 degrees and negative 60 degrees from perpendicular, for example,
approximately 16 degrees from perpendicular, as depicted in FIG. 3 and in
particular
angle alpha (a) as depicted in FIG. 7. FIGS. 3 and 7 depict fluid apertures 14
angled
away from perpendicular towards end-side 120B. In other embodiments, fluid
apertures 14 may be angled away from perpendicular towards head-side 120A.
Fluid
apertures 14 angled away from perpendicular towards head-side 120A may allow
for
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promotion of deceleration of fluid flowing along grates 12. Fluid apertures 14
angled
away from perpendicular towards end-side 120B may allow for inflowing fluid
and
sediment to more directly communicate through fluid apertures 14 and into sump
38.
[0050] Each grate 12 also has an access aperture 16 to permit access
through
grate 12 to sump 38 for maintenance activities, and may, for example, be sized
such
that a vacuum hose is passable through access aperture 16 and into sump 38 of
settling basin insert 10. Access apertures 16 may be generally closer to the
land-side
of settling basin insert 10 for accessibility from access road 60 by a vacuum
truck, for
example.
[0051] In some embodiments, access aperture 16 may include a gasket 17A as
depicted in FIG. 9, defining the opening through which a vacuum hose may pass.
In
some embodiments, access aperture 16 may be closed with a solid cap 17B,
formed
for example, from solid metal, preventing fluid from flowing through access
aperture 16
and into sump 38 unless solid cap 17B is removed, for example, for insertion
of a
vacuum hose through access aperture 16. In other embodiments, access aperture
16
may be covered by metal mesh wiring instead of a solid cap, limiting the size
of
particles that may travel through access aperture 16 into sump 38, while
allowing fluid
communication through access aperture 16.
[0052] Access aperture 16 may be, for example, 550 mm in diameter, and the
centre of access aperture 16 may be approximately 550 mm from the edge of head-
side 120A of grate 12, as depicted in FIG. 6. Access aperture 16 may be
recessed
within grate 12, for example, by 75 mm.
[0053] In some embodiments, access aperture 16 may be closed by a standard-
sized manhole cover, known to a person skilled in the art.
[0054] Each of land-side wall 34 and pond-side wall 36 of settling basin
insert 10
has a guide wall, land-side guide wall 24 and pond-side guide wall 26,
respectively.
Land-side guide wall 24 and pond-side guide wall 26 extend to a height above
grates
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12 and may span the length of settling basin insert 10. Pond-side guide wall
26 may
extend, for example, between 300 mm and 900 mm, preferably 600 mm above grate
12. Land-side guide wall 24 is typically taller than pond-side guide wall 26,
and may
extend, for example, between 450 mm and 1200 mm, preferably 900 mm above grate
12. As depicted, land-side guide wall 24 may be formed separately and attached
to
land-side wall 34, or may be formed integrally with land-side wall 34.
Similarly, as
depicted, pond-side guide wall 26 may be formed separately and attached to
pond-
side wall 36, or may be formed integrally with pond-side wall 36.
[0055] Land-side guide wall 24 may be integrated into a slope of a side of
settling
pond 50', and may act as a retaining wall.
[0056] Land-side guide wall 24 and pond-side guide wall 26 direct fluid
from inlet
40' along the length of settling basin insert 10.
[0057] As depicted, pond-side guide wall 26 is lower in height than land-
side guide
wall 24 such that, in cases of large or very high-velocity fluid flows, fluid
may remain
directed and retained by land-side guide wall 24, but flow over pond-side
guide wall 26
and into settling pond 50' without entering sump 38 or stirring up sediment in
sump 38.
[0058] In some embodiments, in a section 11, sump 38 may be open at both
ends.
In some embodiments, sump 38 is closed by a vertical wall on one or both ends
of a
section 11.
[0059] Each section 11 may have a protruding tongue 13A at its front and a
recessed bell 13B at its end that form an interlock between adjacent sections
11. In
other embodiments, protruding tongue 13A and recessed bell 13B may be omitted.
[0060] A precast concrete box culvert used to form a section 11 may be a
nominally
3000 mm x 2400 mm box culvert, with sump 38 having inner dimensions of 3048 mm
in width and 2438 mm in height, and each of land-side wall 34 and pond-side
wall 26
may have a height of 2500 mm. In some embodiments, a nominally 3000 mm x 1800
11
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mm box culvert may be used to form a section 11. In some embodiments, section
11
may vary further in size, for example, from a nominally 1200 mm x 1200 mm box
culvert up to 3600 mm x 3048 mm box culvert.
[0061] In some embodiments, multiple sections 11 may be interlocked
together, for
example using protruding tongue 13A and recessed bell 13B of adjacent sections
11.
Seams 110 between adjacent sections 11 are depicted in FIG 3.
[0062] Sectioning settling basin insert 10 into sections 11 may allow
settling basin
insert 10 to be more easily transported, moved and installed. Sections 11 may
further
allow for settling basin 10 to be customized to a chosen length based on
design
considerations such as the size of settling pond 50', location of access road
60, and
flow rate and volume of inflowing fluid.
[0063] As illustrated in FIGS. 2 and 3, parts of settling basin insert 10
may differ
from sections 11 at head 20 and end 22, as described in further detail below.
[0064] At head 20 of settling basin insert 10, a top plate 18 may cover a
top section
of settling basin insert 10 and sump 38, and include flow dispersion
protrusions 19
extending upwardly from top plate 18. Inflowing fluid from inlet 40' flows
over top plate
18 and flow dispersion protrusions 19 promote deceleration of fluid flowing
over top
plate 18. Top plate 18 may be solid, and in some embodiments, top plate 18 may
also
have a roughened or perforated surface to increase friction, thus further
promoting
deceleration of fluid flowing over top plate 18. In still other embodiments,
top plate 18
may be omitted.
[0065] Each of head 20 and end 22 of settling basin insert 10 may be closed
by a
vertical plate, by way of a head cap 21 at head 22 of settling basin insert
10, and an
end plug 23 at end 22 of settling basin insert 10, as shown in FIG. 3. As
depicted,
head cap 21 and end plug 23 each contact land-side wall 34, pond-side wall 36
and
base 32, thereby closing off each end of sump 38. In other embodiments, head
cap 21
and end plug 23 may extend into contact with pond-side guide wall 26 or land-
side
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guide wall 24. In some embodiments, these vertical plates may be solid, and
may, for
example, be formed from concrete, metal, fiberglass, wood or plastic. In still
other
embodiments, head cap 21 and end plug 23 may be omitted.
[0066] As illustrated in FIG. 10, in some embodiments, end plug 23 may have
a
drain aperture 230 to allow fluid to drain through from sump 38. In some
embodiments,
drain aperture 230 may be adjacent the top of end plug 23 and the top of drain
aperture 230 may be level with the bottom of grates 12. Drain aperture 230 may
have
a length of between 300 mm and 2400 mm, preferably 1000 mm, and a height of
between 50 mm and 300 mm, preferably 100 mm.
[0067] As illustrated in FIGS. 2 and 3, in some embodiments, absorbent
socks 80
may be placed at intervals along settling basin insert 10 to absorb a liquid
such as oil
or petroleum products that may be present in inflowing fluid. Absorbent socks
80 may
act as oil traps to absorb and retain oils and petroleum-based liquids without
absorbing
or retaining water, for example, by containing a hydrophobic material.
Absorbent socks
80 may be placed at or adjacent to end-side 120B of one or more grates 12, as
shown
in FIGS. 2 and 3, and may be tied down to grate 12 for attachment (not shown).
[0068] In some embodiments, each absorbent sock 80 may be generally
cylindrical
and have an approximate diameter between 35 mm and 150 mm, preferably
approximately 75 mm, and may extend across the length of grate 12 at a length,
for
example, of 3048 mm. In some embodiments, a skin of absorbent sock 80 may be
formed of a suitable material such as polypropylene to contain a filler
material and
allow fluid to pass through to the filler material. Filler material may also
be formed of
polypropylene, or a suitable absorbent material such as cellulose. Other
materials and
configurations suitable for oil or petroleum capture or spill response would
be apparent
to a person skilled in the art.
[0069] As illustrated in FIG. 3, in some embodiments, a baffle 82 may
extend
downwards from a grate 12 into sump 38. Baffle 82 may be a solid plate or
contain
fluid apertures, and may extend across the length of grate 12. Components of
fluid in
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sump 38 that are more buoyant, for example, oil droplets, may rise within the
fluid and
become trapped behind baffle 82, and the remaining fluid may pass under baffle
82,
free to flow along the length of sump 38 in settling basin insert 10.
[0070] As illustrated in FIGS. 2 and 3, in some embodiments, settling basin
insert
may include, beyond end 22, a retaining wall, for example a wing wall 90. Wing
wall
90 may continue beyond end 22 of settling basin insert 10 from land-side wall
34. The
base of wing wall 90 may be level with base 32 and the top of wing wall 90 may
be
level with land-side guide wall 24, or extend above land-side guide wall 24.
The height
from base to top of wing wall 90 may be 4548 mm. Wing wall 90, as shown in
FIGS. 2
and 3, may have buttresses 92 that project perpendicularly from wing wall 90
to
provide support to wing wall 90. Wing wall 90 may be at an angle, for example
45
degrees, from end 22 of settling basin insert 10, as shown in FIG. 2.
[0071] The dimensions of settling basin insert 10, and its component parts,
may be
scaled smaller or larger, for example, depending on the flow rate and volume
of
inflowing fluid and the size of inlet 40', or an amount of area upstream
draining to
settling basin insert 10 via inlet 40'.
[0072] FIG. 11 depicts a cross-section view of settling pond 50' with
settling basin
insert 10 installed, along lines III-Ill and lines X-X of FIG. 2. Arrows /'
denote a primary
example first path of fluid over and along settling basin insert 10, typical
of small flows.
[0073] In use, the settling basin insert 10 remains full of fluid below
grates 12 and
top plate 18, with grates 12 and top plate 18 being located approximately at
the
permanent water level of settling pond 50'.
[0074] In embodiments of settling basin insert 10 having end plug 23 with
drain
aperture 230, the permanent water level of settling pond 50' may align with
the level of
fluid within sump 38 at a level below drain aperture 230 during typical small
flows of
inflowing fluid. The standing level of fluid in sump 38 may be, for example,
350 mm
below the top of grates 12.
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[0075] Fluid flows towards head 20 of settling basin insert 10 from inlet
40'. Inlet 40'
is positioned level with or just above top plate 18. The incoming fluid flows
over top
plate 18 and among flow dispersion protrusions 19, and energy is lost, thus
promoting
deceleration of fluid flowing over top plate 18.
[0076] Land-side guide wall 24 and pond-side guide wall 26 may direct
incoming
fluid along the length of settling basin insert 10. Fluid may communicate
between grate
12 and sump 38 through fluid apertures 14. Solid particles in the incoming
fluid flow
settle through grates 12 as sediment S' into sump 38. Energy is dissipated as
the
direction of fluid flow is changed as streams of fluid travel through fluid
apertures 14,
and energy is lost to friction as fluid flows along grates 12.
[0077] Furthermore, fluid flowing along settling basin insert 10 may
contact
absorbent socks 80, which may act as oil traps to absorb and retain oils and
petroleum-based liquids without absorbing or retaining water in the fluid.
[0078] Fluid flowing along settling basin insert 10 through sump 38 may
contact
baffle 82 and baffle 82 may trap buoyant particles, for example oil droplets,
from the
fluid.
[0079] As a result, fluid flowing along and through settling basin insert
10, as well
as into sump 38, is likely to have a relatively low velocity. Thus more solid
particles
may settle into sump 38 before the fluid flow reaches pond 50'.
[0080] As noted, fluid flowing into pond 50' with high velocity may cause
churning
of the pool P' and mixing of dirt and sediment. Mixed dirt and sediment may
then be
carried out of pond 50' by fluid flowing out through an outlet (not shown).
Conversely,
fluid that flows into pond 50' at low velocity may be less likely to cause
churning in pool
P' and mixing of dirt and sediment, which may ultimately reduce the amount of
dirt and
sediment carried out of pond 50' by outflowing fluid.
[0081] Furthermore, fluid that flows into pond 50' with less solid
particles may
CA 02953931 2017-01-06
reduce the amount of dirt and sediment that enters pond 50'.
[0082] In certain circumstances, the flow rate of inflowing fluid may be
much higher
than normal. Such circumstances may occur, for example, in the case of a storm
event
or periods of heavy rainfall intensity.
[0083] FIG. 12 again depicts a cross-section view of pond 50' with settling
basin
insert 10, along lines III-Ill and lines X-X of FIG. 2. Arrows I" denote a
secondary
example path of fluid over and along settling basin insert 10, typical of
large or very
high-velocity flows.
[0084] As is the case with small flows, some inflowing fluid lands on top
plate 18
and among flow protrusions 19, and is directed along the length of settling
basin insert
by land-side guide wall 24 and pond-side guide wall 26. Fluid then passes
along
grates 12.
[0085] Large or very fast fluid flows tend to rush across grates 12, with
relatively
little fluid communicating through fluid apertures 14. In effect, grates 12 at
least
partially separate the fast-flowing incoming fluid of a large flow from the
relatively still
fluid previously accumulated in sump 38. As will be apparent, this limits
mixing of the
inflowing fluid with the fluid in sump 38, and likewise limits churning of
sump 38 fluid.
Accordingly, separating large flows from fluid in sump 38 may reduce the
likelihood of
sediment S' in sump 38 being mixed with the flows carried out of settling
basin insert
10 and into pond 50'.
[0086] Furthermore, the height of pond-side guide wall 26 allows for such a
large
flow to flow directly over pond-side guide wall 26 and into pond 50, while
land-side
guide wall 24 continues to direct the large flow over grates 12 along the
length of
settling basin insert 10.
[0087] Grates 12 effectively define a barrier over sump 38. Small, slow
flows may
be permitted to enter sump 38 through fluid apertures 14 for settling and
retention of
16
CA 02953931 2017-01-06
sediment, while flows that are too large or too fast for effective settling
may be
practically or fully segregated from fluid in sump 38. Instead, large flows
may be
conveyed into pond 50' over pond-side guide wall 26 so that scour or churn of
previously-captured sediment S' is avoided and such sediment is retained in
sump 38.
[0088] Furthermore, at end 22 of settling basin insert 10, drain aperture
230 of end
plug 23, as shown in FIG. 10, may allow for capacity in sump 38 of the height
of drain
aperture 230 below grate 12. For example, if drain aperture 230 extends 50 mm
below
grate 12, a permanent standing level of fluid inside sump 38 may be 50 mm or
more
below the bottom of grate 12, and the top 50 mm of sump 38, may be available
to
receive inflowing fluid from a first flush from a storm event, which may
increase
capture of sediment S' in sump 38. If sump 38 is filled with fluid up to the
top 50 mm of
sump 38, inflowing fluid will fill to the top of grate 12 and flow across the
top of grate
12, as discussed above.
[0089] Fluid that exits settling basin insert 10 at end 22 may contact and
be
directed by wing wall 90 towards the body of pond 50'. Wing wall 90 may
prevent such
fluid flow from eroding slopes of pond 50'.
[0090] Sediment S' collected in sump 38 may be collected in a smaller area
to be
periodically cleaned by a vacuum truck with a vacuum hose entering sump 38
through
an opened access aperture 16, instead of draining the whole pond containing
sediment spread over a larger area as in a traditional maintenance method.
Fluid in
sump 38 may be pumped directly into pond 50', for example, using a pump to
dewater
settling basin insert 10, leaving sediment S' in sump 38 to be vacuumed out
and
disposed of.
[0091] Settling basin insert 10 may reduce the disruption of existing water
in sump
38 to avoid settled sediment S' at the bottom sump 38 from mixing with and
becoming
entrained in the water flowing into settling pond 50', particularly in cases
of high water
flow. This may allow for a higher inflow rate in use.
17
CA 02953931 2017-01-06
[0092] Furthermore, the presence of grates 12 may prevent fluid in sump 38
of
settling basin insert 10 from being in direct sunlight, and as such fluid in
sump 38 may
be cooler than the fluid in pool P' in pond 50', which may have beneficial
effects on the
surrounding ecosystem.
[0093] Of course, the above described embodiments are intended to be
illustrative
only and in no way limiting. The described embodiments are susceptible to many
modifications of form, arrangement of parts, details and order of operation.
The
invention is intended to encompass all such modification within its scope, as
defined
by the claims.
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