Note: Descriptions are shown in the official language in which they were submitted.
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APPARATUS FOR TREATING WASTEWATER
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates generally to an apparatus
for treating sewage and wastewater, and more particularly,
to an apparatus for effectively treating high density sewage
and wastewater by which a low density material separation
type pretreatment process and an anaerobic digestion main
treatment process are combined into a single process such
that the low density materials contained in sewage and
wastewater are separated using density difference in the
pretreatment process and that agitation and solid-liquid
separation are carried out by anaerobic digestion in the
main treatment process.
Description of the Related Art
In general, treatment of sewage and wastewater is
to eliminate harmful material and pollution from sewage
and wastewater discharged from plants and offices.
The treatments may be classified into a physical
treatment, a chemical treatment, a biological treatment,
a thermal treatment, and an advanced oxidation process (AOP)
according to kinds and types of sewage and wastewater.
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The sewage and wastewater treatment process includes
a pre-treatment process of treating sewage and wastewater
primarily and a main treatment process of secondarily
treating the pre-treated sewage and wastewater.
The pre-treatment process performs an important role
of enhancing efficiency of the main treatment process.
In the pre-treatment process, oil component, various
fruit seeds, various foods that are dissolved slow,
indecomposable vinyl are pre-treated.
Thus, sewage and wastewater is primarily decomposed
in the pre-treatment process and may be transformed into
organic material to be easily treated in the main treatment
process.
During the main treatment process, the sewage and
wastewater transformed into organic material during the
pre-treatment process is treated by anaerobic digestion.
However, the existing pre-treatment process has
drawbacks. That is, an existing pre-treatment unit does
not have a function of selecting and separating low density
material and very-slowly-decomposing material of which
particle solids are introduced into the pre-treatment unit
is introduced into the main treatment process without
pre-treatment so that the main treatment process may be
excessively increased to treat such material and treatment
efficiency may be remarkably deteriorated.
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Even in the main treatment process, since the sewage
and wastewatertreatedinthe pre-treatment process contains
various materials such as low-density fat and oil,
non-decomposable wastewater sludge, easily-decomposable
solids (foods) , it is very difficult to build an anaerobic
digester satisfying all decomposition conditions for the
respective materials.
Thus, a completely mixed flow reactor anaerobic
digester employed in the existing main treatment process
is designed by assuming that features of all materials of
sewage and wastewater are under the same conditions.
That is, since the completely mixed flow reactor
anaerobic digester is designed and driven based on a material
having the longest decomposing time for increase of
efficiency, low density organic matters and microorganisms
exist in the anaerobic digester so that efficiency of the
anaerobic digestion is very low.
Moreover, since it is substantially impossible to
cope with the existing anaerobic digestion (long treatment
time, low generation of methane, and increase of
post-treatment costs due to a lot of staying material after
the anaerobic digestion) against the situation where the
existing mostly-used disposal of waste is completely banned
under the marine dumping ban, solutions of radically solving
this problem are required.
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Upf lowAnaerobic Sludge Blanket (UASB) maybe a typical
method among the solutions.
However, UASB has difficulties on mixing, securing
of microorganism, big scale apparatuses, management of rapid
drop of pH, especially cannot cope with treat introduced
solid material, and thus has limit on efficiency.
In addition, since the anaerobic digestion is used
just to reduce pollutants from sewage and wastewater, the
problem of low efficiency is solved through a rear side
water treatment or by spraying sewage and wastewater on
soil.
However, since recently methane is spotlighted as
alternative energy and has an important impact on global
warming, increase amount and use of methane in organic
material directly mean to increase production of energy
and to protect environment.
Thus, technology of increasing production of methane
from organic material as much as possible to make the rear
side water treatment and staying solid treatment be easy
should be required. However, it is difficult to achieve
this purpose yet.
SUMMARY OF THE INVENTION
The present invention has been made in view of the
aboveproblem,andthepresentinventionprovidesanapparatus
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for treating sewage and wastewater by applying low density
separation method to a pretreatment process to separate low
density fat and oil components, organic material, and
suspended matter from sewage and wastewater, by decomposing
pollutants with organic acid to accelerate a following
anaerobic digestion, and by applying anaerobic digestion
in a main treatment process to convert the fat and oil
introduced from the pretreatment process into digestion gas
without separation.
In accordance with the aspects of the present invention,
there is provided an apparatus for treating sewage and
wastewater, including: a pretreatment unit separating low
density material from the sewage and wastewater using a
low-density material separation; a storage tank storing the
sewage and wastewater supplied from the pretreatment unit;
and a main treatment unit treating the sewage and wastewater
supplied from the storage tank in anaerobic digestion to
produce methane gas from the sewage and wastewater such that
stayed time of the methane gas is increased during the
ascending of the methane gas and that agitation of the sewage
and wastewater is carried out.
As described above, the apparatus for treating sewage
and wastewater according to the present invention has the
following advantages.
First, since the pretreatment process using the low
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density material separation and the main treatment process
usingtheanaerobicdigestionareintegratedintooneprocess,
the lowdensitymaterialcontainedinthesewageandwastewater
is separated in the pretreatment process due to density
difference and the agitation and the solid-liquid separation
are carried out by the anaerobic digestion in the main
treatment process so that high concentration sewage and
wastewater may be effectively treated.
Second, in the pretreatment unit, since the low-density
1o material separators are disposed in multiple layers in the
first reactor, the stay chambers are formed in the lower
side of the low-density material separator by the sewage
and wastewater, and the low density material floats on the
water surface within the stay chambers and are not discharged
with the sewage and wastewater when the sewage and wastewater
is discharged, the low density material such as fat and oil
component of the sewage and wastewater maybe easily separated
before the main treatment and may be decomposed organic acid
to accelerate following anaerobic digestion so that the fat
and oil component is transformed into digestion gas without
being separated independently.
Third, in the pretreatment unit, since gas is supplied
or discharged through the gas pipes connected to the stay
chambers to control the water level within the stay chambers,
the low density material may be removed more effectively.
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Fourth, in the main treatment unit, the first and second
activating devices with different shapes are arranged in
the second reactor. The stay chambers for gas are formed
in the first and second activating devices. The gas generated
from the ascending sewage and wastewater is gathered in the
stay chambers and ascends through the transfer pipes
sequentially. During this ascending, since the lower sides
of the transfer pipes contact the water surface, the low
density material on the water surface is transferred into
the upper chamber and the solids under the water surface
remain so that the solid-liquid separation is carried out.
Fifth, in the main treatment unit, when the gas and
the sewage and wastewater ascend additionallyandpass through
the anaerobic reaction activating devices, the gas is
discharged from the lower chamber spontaneously to form a
space and high density material such as the solids and
microorganism requiring a longer decomposing time are
introduced into the space so that the high density material
is transferred into the lower chamber as much as the amount
of the discharged gas resulting in improving treat rate and
efficiency.
Sixth, in the main treatment unit, the gas gathered
in the lower chamber of the second reactor is discharged
such that the sewage and wastewater drops from the upper
chamber to the lower chamber, resulting in agitating without
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driving power. Simultaneously, solids and microorganisms
are transferred into the lower chamber to prevent pH from
being decreased in the lower chamber.
Seventh, in the main treatment unit, since it is
substantially impossible to observe the internal side of
the reactor and to cope with a trouble because the anaerobic
digestion treats very highconcentrated sewage and wastewater,
the apparatus of the present invention prevents trouble from
occurring fundamentally by repeating processes such as the
agitation by the gas transfer, the agitation by discharging
gas, and fluidity caused by gas stay.
BRIEF DESCRIPTION OF THE DRAWINGS
The objects, features and advantages of the present
invention will be more apparent from the following detailed
description in conjunction with the accompanying drawings,
in which:
FIG. 1 is a schematic view illustrating an apparatus
for treating sewage and wastewater including a pretreatment
unit, a storage tank, and a main treatment unit according
to an exemplary embodiment of the present invention;
FIG. 2 is a side view illustrating an internal structure
of the pretreatment unit of FIG. 1;
FIG. 3 is a partially-enlarged view of a transfer pipe
of the apparatus for treating sewage and wastewater of FIG.
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2;
FIG. 4 is a side sectional view schematically
illustrating an internal structure of a second reactor of
the main treatment unit of FIG. 1;
FIG. 5 is a perspective view of a first plate activating
unit in the second reactor of FIG. 4;
FIG. 6 is a view partially illustrating gas gathered
in a first stay chamber ascending through the first activating
unit of FIG. 5;
FIG. 7 is a perspective view a second block activating
unit of FIG. 4;
FIG. 8 is a side view schematically illustrating the
gas gathered in the first stay chamber ascending through
the second activating devices of FIG. 7; and
FIG. 9 is a section view showing another example of
the main treatment unit of FIG. 4 in which a gas circulation
unit is additionally disposed to a side of the second reactor.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
Hereinafter, an apparatus for treating sewage and
wastewater according to exemplary embodiments of the present
invention are described in detail with reference to the
accompanying drawings.
As illustrated in FIG. 1, an apparatus 1 for treating
sewage and wastewater according to an exemplary embodiment
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of the present invention includes a low-density material
separation type pretreatment unit 2, a storage tank 3 for
storing treated water supplied from the pretreatment unit
2, and a main treatment unit 4 for treating the treated water
supplied from the storage tank 3 in anaerobic digestion to
produce methane gas from the sewage and wastewater such that
stayed time of the methane gas is increased during the
ascending of the methane gas and that agitation of the sewage
and wastewater is effectively performed.
In the apparatus, the pretreatment unit 2 removes
particle solids contained in the high concentration sewage
and wastewater in the low-density material separation,
pre-treats the removed particle solids to be fed to the main
treatment unit 4.
The pretreatment unit 2, as illustrated in FIGS. 2
and 3, includes a first reactor 5 in which the sewage and
wastewater is introduced into to be treated and discharged
out, an agitator 7 provided in the first reactor 5 to agitate
and uniformly mix up the sewage and wastewater and bubbles,
at least one low-density material separator 9 dividing an
internal space of the first reactor 5 into upper and lower
chambers, allowing the ascending sewage and wastewater and
a gas to pass therethrough sequentially such that low density
material floats on the water surface within a stay chamber
V due to the bubbles generated from the sewage and wastewater
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introduced during the ascending or a gas injected thereinto
from the outside, and controlling a level of the water surface
to prevent the low density material floating on the water
surface from ascending such that the low density material
is separated from the sewage and wastewater, and a particle
solid discharging pipe 11 disposed near the water surface
formed at the lower side of the low-density material separator
for discharging the low density material floating the water
surface W to the outside when the water level of the stay
chamber V descends.
In this apparatus for treating sewage and wastewater,
the sewage and wastewater may be introduced into and stored
in the tank-shaped first reactor 5.
That is, the first reactor 5 includes a wastewater
introducing pipe 13 connected to the lower side thereof such
that the sewage and wastewater is supplied into the first
reactor 5 the wastewater introducing pipe 13.
The sewage and wastewater introduced through the
wastewater introducing pipe 13 fills up the internal space
of the first reactor 5 by gradually ascending from the bottom .
During this process, sludge with a preset weight or
heavier contained in the sewage and wastewater is deposited
in a precipitation tank.
A gas pipe 15 is connected to a side of the first reactor
5. The gas pipe 15 is communicated with the stay chamber
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V to discharge the gas gathered by the low-density material
separator 9 to the outside or to inject an external gas into
the stay chamber V.
The first reactor 5 includes a treated water discharging
pipe 17 connected to the upper side to discharge the water
treated while passing through the low-density material
separator 9 to the storage tank 3.
The first reactor 5 includes a deposit discharging
pipe 19 connected to the lower side to condense and discharge
the deposits, so that the deposits deposited from the upper
side in the first reactor may be discharged along a slope
to the deposit discharging pipe 19.
The agitator 7 includes a motor assembly M disposed
on the top of the first reactor 5 and an impeller B mounted
around a rotating shaft S of the motor assembly M.
In this case, the impeller B may be mounted around
the lower side of the rotating shaft S and may be disposed
under the uppermost water surface W1.
Sizeandnumberof the impeller Bmaybeproperlyselected
according to treatment capacity of the first reactor 5.
When the motor assembly M is driven, the impeller B
may rotate and mix up the sewage and wastewater full in the
first reactor 5 uniformly.
The low-density material separator 9 includes a single
or a plurality of low-density material separators.
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In more detail, the low-density material separator
9 includes a blocking plate 21 dividing the internal space
of the first reactor 5 into the upper and lower chambers
and formed with a plurality of passing holes h, and a plurality
of transfer pipes 23 protruding downwardly from the lower
sideof the blocking plate2landcommunicatedwiththepassing
holeshsuchthatthesewageandwastewaterflowstherethrough.
In the low-density material separator 9, the blocking
plate is made of a thin plate and is disposed transversally
in the first reactor 5 to divide the internal space of the
first reactor 5 into the upper and lower chambers.
Thus, the sewage and wastewater filled in the lower
side of the blocking plate 21 may move to the upper side
of the blocking plate 21 only when passing through the passing
holes handthe transferpipes 23 communicated with the passing
holes h.
Since the transfer pipes 23 have internal passages,
the sewage and wastewater may be transferred to the upper
and lower chambers through the transfer pipes 23.
At least one of the transfer pipes 23 protrudes
downwardly from the blocking plate 21 by a preset length.
When the first reactor 5 is filled with the sewage
and wastewater, the water surface W is formed and gradually
ascends and finally reaches the lower ends of the transfer
pipes 23 so that the stay chambers V are formed by the blocking
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plate 21, the outer rims of the transfer pipes 23, and the
water surface W.
In this case, the water surface W is formed on the
same line as the lowermost ends of the transfer pipes 23.
Thus, when the stay chamber V is additionally filled
with gas generated from the sewage and wastewater or an
external gas is additionally injected through the gas pipe
15, the water level descends and the sewage and wastewater
move to the lower side of the transfer pipes 23 and finally
ascend into the upper chamber through the transfer pipes
23.
At this time, the sludge floating on the water surface
W, especially, low density materials such as scum, oil
component, and fruit seeds are filtered by the lower rims
of the transfer pipes 23 and thus prevented from moving to
the upper chamber together with the ascending sewage and
wastewater. Thus, the low density material is separated
from the sewage and wastewater.
Moreover, as illustrated in FIG. 3, at the lower rims
of the transfer pipes 23 filters 25 are formed.
The filters 25 may filter the sludge floating on the
water surface W, especially scum, oil component, and fruit
seeds more effectively.
The low density materials are not discharged and float
on the water surface W fora long time so that time for natural
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decomposition may be secured and only decomposed material
may be transferred into the upper chamber.
Meanwhile, on the water surface formed in the stay
chamber, the water level descend as the gas generated from
the sewage and wastewater is gathered in the stay chamber
V or the amount of the external gas injected into the stay
chamber V through the gas pipe 15 is increased.
The water level descends to the same height as that
of an inlet 27 of a particle solid discharging pipe 11. In
this case, material with relatively low density of the low
densitymaterial floating on the water surface W is discharged
to the outside through the inlet 27 of the particle solid
discharging pipe 11 except for material with relatively high
density so that the accumulation of the low density material
is decreased.
Thus, the relatively-low density material is
discharged through the particle solid discharging pipe 11
and the relatively-high density material resides on the water
surface so that the secondary separation is performed.
On the contrary, when a valve 6 of the gas pipe 15
is open, the gas gathered in the stay chamber V is discharged
out so that a pressure of the stay chamber V is decreased
and the water surface W ascends so that the accumulation
of the low density material is also increased.
In this case, the water surface W is formed above the
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particle solid discharging pipe 11 so that the low density
material is not discharged out through the particle solid
discharging pipe 11 but floats on the water surface W for
a long time resulting in disintegrating organically.
Therefore, the valve 6 of the gas pipe 15 is properly
controlled such that the low density material may be
effectively separated by adjusting the level in the stay
chamber V or through the biological treatment of floating
the low density material for a long time to be decomposed.
During the above-mentioned process, high density
material of the foreign matter contained in the sewage and
wastewateraredepositeddownandforeign matterofrelatively
low density floats on the water surface W in the stay chamber
V around the transfer pipes 23 resulting in being decomposed.
The low density material floating on the water surface
W may be removed secondarily by which the low density material
is discharged through the particle solid discharging pipe
11 to the outside when the level reaches the height of the
particle solid inlet 27.
In more detail, the particle solid discharging pipe
11 includes the inlet 27 throughwhichthe low densitymaterial
is introduced and an outlet 29 through which the introduced
low density material is discharged.
The inlet 27 has a large sectional area such that the
low density material floating on the water surface W may
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be easily introduced into the particle solid discharging
pipe 11. On the contrary, the outlet 29 has a sectional
area less than that of the inlet 27 so that the low density
material may be effectively discharged.
The inlet 27 is lower than the water surface W and
higher than the lowermost ends of the transfer pipes 23.
Thus, when the level descends and reaches the height
of the inlet 27, the low density material such as scum, oil,
etc. floating on the water surface W enters the inlet 27
and is discharged through the outlet 29 to be removed
secondarily.
The uppermost particle solid discharging pipe 35 of
the particle solid discharging pipe 11 is configured such
that an inlet 33 is disposed near the uppermost water surface
Wl and an outlet 31 extends out of the first reactor 5 and
is connected to the lower side of the first reactor 5.
Thus, since the low density material such as scum,
oil component, and fruit seed enters the inlet 33 of the
particle solid discharging pipe 35 and returns back to the
lower side of the first reactor 5 through the outlet 31 even
when the low density material floats on the uppermost water
surface Wl, the low density material still resides in the
first reactor 5 and is prevented from being transferred to
the main treatment unit 4.
Meanwhile, the high density material of the sludge
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contained in the sewage and wastewater is deposited down
and is accumulated on the bottom of the first reactor 5.
The deposited high density material is discharged to
the outside through the deposit discharging pipe 19.
The operations of the pretreatment unit 2 will be
described as follows.
As illustrated in FIGS. 2and3, the sewage and wastewater
is introduced into the first reactor 5 through the wastewater
introducing pipe 13 and the gas injection pipe 15.
The sewage and wastewater introduced into the f irst
reactor 5 ascends and reaches the lower sides of the transfer
pipes 23 of the first low-density material separator 9.
As a result, the water surface W of the sewage and
wastewater is formed on the same line as that the lower sides
of the transfer pipes 23 and the stay chambers V are formed
around the transfer pipes 23 so that the gas generated from
the sewage andwastewaterandinjectedfromtheoutsidethrough
the gas pipe 15 is gathered.
The level of the sewage and wastewater gradually ascends
as the sewage and wastewater is supplied and the sewage and
wastewater moved to the upper chamber through the transfer
pipes 23.
Since the starting point where the material at the
lower side of the first reactor 5 moves to the upper chamber
is at the lowermost portions of the transfer pipes 23, the
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material floating in the sewage and wastewater is separated
due to the density difference and moved to the upper chamber.
The density difference between the floating materials
is determined by surface tension generated by a length of
the funnel-shaped transfer pipes 23 and the water surface.
That is, the longer the funnel-shaped transfer pipes 23 is
and the wider the water surface W is the larger the density
difference is.
Thus, the majority of bubbles generated in the first
reactor 5 stays on the uppermost end of the level of the
sewage and wastewater and the water surface W of the sewage
and wastewater is mostly formed with the low density material
by the surface tension.
Consequently, since the low density materials are in
the upper chamber at the ends of the transfer pipes 23, material
separation in which density of material is lower as the
position in the first reactor 5 is high.
In the first reactor 5, the motor assembly M of the
agitator 7 is driven so that the sewage and wastewater may
be mixed up uniformly by the rotation of the impeller B.
The low density material such as scum, oil component,
and fruit seed of the sludge floating on the water surface
W is blocked by the lower rims of the transfer pipes 23 and
does not move to the upper chamber.
The sawtooth-shaped filters 25 are formed at the lower
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rims of the transfer pipes 23 to filter and prevent the low
density materials from moving to the upper chamber primarily.
In this case, the filtered low density materials float on
the water surface for a long time and may be disintegrated
organically.
Moreover, since the valve 6 of the gas pipe 15 is properly
controlled to adjust the amount of the gas gathered in the
stay chambers V and to control the level of water, the
discharged amount of the low density material may be
controlled.
That is, the amount of the gas generated from the sewage
and wastewater is gathered in the stay chambers V and the
external gas injected into the stay chambers V through the
gas pipe 15 is increased, the level of water is lowered down
and simultaneously the accumulation of the low density
material is decreased (in a case when the amount of the low
density material is relatively small).
On the contrary, in a case when the valve 6 of the
gas pipe 15 is open, since the gas gathered in the stay chambers
V is discharged to the outside, the pressure in the stay
chambers V is decreased and the level of water ascends so
that the accumulationof the lowdensitymaterial is increased .
In this case, since the water surface W is formed above
the inlet 27 of the particle solid discharging pipe 11, the
low density material is not discharged to the outside through
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the particle solid discharging pipe 11. That is, the low
density material floats on the water surface W for a long
time.
When the level of water descends and reaches the height
of the particle solid discharging pipe 11, the low density
material floating on the water surface W is discharged to
the outside through the particle solid discharging pipe 29
so that the low density material may be removed secondarily.
That is, when the water surface descends and reaches
the height of the inlet 27, the low density material such
as scum, oil, etc. floating on the water surface W may be
introduced through the inlet 27 and then be discharged out.
Even in a case when the low density material such as
scum, oil component, and fruit seeds floats on the water
surface formed at the uppermost end of the first reactor
5, the low density material enters the inlet 33 of theparticle
solid discharging pipe 35 and returns back to the lower side
of the first reactor 5 so that the low density material may
reside in the first reactor 5 still and may be prevented
from being transferred to the main treatment unit 4.
As described above, thelow- dens ity material separator
9 easily separates fat and oil components from the sewage
and wastewater and decomposes the same into organic acid
to accelerate the following anaerobic digestion so that the
fat and oil component may be transformed into the digested
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gas without separation and treatment.
The high density material of the sludge contained in
the sewage and wastewater is deposited down the lower side
and accumulated on the bottom of the first reactor 5.
Meanwhile, the storage tank 3 is disposed between the
pretreatment unit 2 and the main treatment unit 4 to make
play a role of an acid fermenter, to store the sewage and
wastewater temporally and to feed the sewage and wastewater
to the main treatment unit 4.
Since the storage tank 3 stores the sewage and wastewater
treated in the pretreatment unit 2 temporally, the storage
tank 3 maybe omitted when the pretreatment unit 2 is connected
directly to the main treatment unit 4.
The main treatment unit 4, as illustrated in FIGS.
4 to 6, includes a second reactor 40 in which the sewage
and wastewater is introduced to be treated by the anaerobic
reaction and discharged, anaerobic reaction activating
devices C1, C2, C3, and C4 arranged in multilayer in the
second reactor 40 in which solid-liquid separation occurs
and agitation is carried out during methane gas and the sewage
and wastewater ascend, a gas circulation unit 43 discharging
gas in the lower side of the second reactor 40 to the upper
side to make the sewage and wastewater flow to the lower
side so that the agitation may occur and solid materials
flow down, and a treated water circulation unit 45 disposed
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at a side of the second reactor 40 to circulate the treated
water in the upper side to the lower side.
In the main treatment unit 4, the second reactor 40
has an internal space into which the sewage and wastewater
is introduced and stored. An introducing pipe 47, through
which the sewage and wastewater enters the second reactor
40, is connected to the lower side of the second reactor
40 and the sewage and wastewater may be introduced into the
second reactor 40.
The second reactor 40 includes a gas discharging pipe
49 and a treated water discharging pipe 51 connected to the
upper side thereof. Thus, the gas generated during the
anaerobic reaction in the second reactor 40 is discharged
through the gas discharging pipe 49 and the treated water
is discharged through the treated water discharging pipe
51.
When the sewage and wastewater is supplied into the
second reactor 40, methane gas is generated at the lowermost
side of the second reactor 4 0 and gradually ascends and finally
reaches the anaerobic reaction activating devices C1, C2,
C3, and C4.
The anaerobic reaction activating devices C1, C2, C3,
and C4 include first activating devices C1 and C2 that are
arranged in the lower side of the second reactor transversally
to bring a primary anaerobic reaction and to activate the
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solid-liquid separation and agitation by the generated gas,
and second activating devices C3 and C4 that are arranged
transversally in the upper side of the second reactor 40
to bring a secondary anaerobic reaction and to mix the sewage
and wastewater uniformly in every block.
The sewage and wastewater introduced into the second
reactor 40 pass through the first activating devices C1 and
C2 and the second activating devices C3 and C4 sequentially
to ascend and the anaerobic treatment, the solid-liquid
separation, and the agitation may be carried out
simultaneously.
In more detail, each of the first activating devices
C1 and C2, as illustrated in FIGS. 5 and 6, includes a plate
shape 53 blocking the internal space of the second reactor
40 transversally and at least one first fluid transfer pipe
57 protruding downwardly from the plate 53 to form a
through-hole 55 such that the sewage and wastewater and gas
may pass therethrough.
When the sewage and wastewater is introduced into the
second reactor 40, the sewage and wastewater ascends from
the lower side to the upper side of the second reactor 40
so that the sewage and wastewater passes through the first
activating devices C1 and C2 sequentially through the at
least one first fluid transfer pipe 57.
The solid-liquid separation and agitation may be
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carried out while the sewage and wastewater passes through
the first activating devices Cl and C2 sequentially.
The ascending sewage and wastewater reaches the lower
end line of the first fluid transfer pipe 577 to form the
water surface.
As such, when the water surface is formed on the lower
end line of the first fluid transfer pipe 57, a plurality
of the first stay chambers V is formed around the first fluid
transfer pipe 57.
In this case, the first fluid transfer pipe 57 may
be relatively long so that a larger first stay chamber V
may be formed.
That is, preferably, the first fluid transfer pipe
57 is longer than a second fluid transfer pipe 70 provided
in the later-described second activating devices C3 and C4.
Thus, since the amount of gas gathered in the first
stay chambers V of the first activating devices Cl and C2
is greater than that in the first stay chambers V of the
second activating devices C3 and C4, more amount of gas may
be supplied from the lower chamber to the upper chamber of
the second reactor 40 when the gas circulates the upper and
lower chambers by the later-described gas circulation unit
43 and due to this a large amount of treated water may be
transferred from the upper chamber to the lower chamber so
that efficiency of agitation may be improved.
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The gas ascended from the lower chamber of the second
reactor 40 is gathered in the first stay chambers V of the
first activating devices C1 and C2. When a preset amount
of the gas is gathered, the gathered gas is scattered in
all directions by the pressure of the first stay chambers
V so that the gathered gas pushes the sewage and wastewater
out of the first stay chambers V.
At this time, since the water surface and the lower
end line of the first fluid transfer pipes 57 are on the
same line, the gas pushed the sewage and wastewater out of
the first stay chambers V is injected into the first fluid
transfer pipes 57.
Deposition occurs spontaneously by the surf ace tension
of the sewage and wastewater on the water surface so that
only the lowest density wastewater (in which at least
microorganisms and SS type solids only exist) is injected
into the first fluid transfer pipes 57.
Thus, the low density wastewater ascends through the
first fluid transfer pipes 57 but the relatively high
concentration microorganism and solid material do not flow
to the upper chamber. Time where the microorganism and solid
material stay in the lower chamber is increased.
Thus, the solids contained in the sewage and wastewater
are separated into the low concentration density solids and
the high density solids.
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Moreover, since microorganism in the sewage and
wastewater is very small, methane gas generated by the
microorganism has fine bubbles that cannot be watched with
naked eyes.
It is difficult to bring the agitation effect by the
fine bubbles rather the fine bubbles make a negative role
of floating sludge.
However, the fine bubbles transferred into the first
stay chambers V for gas are transferred into the upper chamber
through the first fluid transfer pipes 57 in the form of
very big bubbles in a next transfer stage.
That is, a plurality of fine bubbles generated in the
vicinity of the water surface is concentrated to the first
fluid transfer pipes 57 with a relatively small sectional
area and ascend then are combined with each other to form
big bubbles so that the agitation may be carried out more
effectively.
Moreover, since some of the fine bubbles around the
microorganism is combinedwithabigbubblestreamtransferred
through the first fluid transfer pipes 57, the fine bubbles
around the microorganisms are separated from the
microorganisms more easily so that contact between the sewage
and wastewater and the microorganism may occur more easily
and that the microorganism may be increased very fast.
Thus, the fine bubbles working as a negative factor
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in the existing process during this process rather plays
an important role of enhancing efficiency.
The first activating devices Cl and C2 maybe configured
such that the plates 53 are arranged in a single layer or
in a two more layers. This configuration may be determined
according to a designer's choice.
The gas passed through the first activating devices
Cl and C2 ascends further and finally reaches the second
activating devices C3 and C4.
Each of the second activating devices C3 and C4, as
illustrated in FIGS. 7 and 8, includes at least one
block-shaped unit reactor 60.
Since all the unit reactors 60 have the same structure,
only one unit reactor 60 will be described.
The block-shaped unit reactor 60 includes upper and
lower frames 62 and 64 disposed to correspond to each other,
legs 66 connecting the upper frame 62 to the lower frame
64, oblique plates 68 provided in the upper frame 62 to divide
the internal space of the second reactor 40 into an upper
chamber and a lower chamber, and second fluid transfer pipes
70 provided in the oblique plates 68 to provide passages
through which a fluid passes.
In the second activating devices C3 and C4, the upper
frame 62 has protrusions 72 and the legs 66 have coupling
holes 74 formed on the lower ends into which protrusions
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CA 02771637 2012-03-12
72 of another upper frame 62 are inserted.
Thus, at least two unit reactors 60 are stacked to
form the second activating devices C3 and C4.
The oblique plates 68 are provided in the upper frame
62 to block the fluid from being transferred.
In this case, two sets of the oblique plates 68 are
arranged wherein the plates 68 of each set are downwardly
oblique and have at least one second fluid transfer pipe
70 formed at the center thereof to serve as a passage through
which the sewage and wastewater passes.
When the sludge is deposited on the upper surface of
the oblique plates 68, the sludge moves downwardly along
the oblique plates 68 and thus is prevented from being
accumulated.
Although the two sets of the oblique plates 69 are
described above,the present invention is not limited thereto
but only one oblique plate 68 may be disposed and in this
case only one second fluid transfer pipe 70 protruded.
Fluid may flow through the second transfer pipes 70.
Thus, when the unit reactors 38 are stacked in the
second reactor 40, each of the unit reactors 38 arranged
on the same layer contacts with each other and the oblique
plates 68 are transversally arranged on the same line as
that of an oblique plate of an adjacent unit reactors 38
so that the internal space of the second reactor 40 is divided
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into upper and lower chambers.
The second fluid transfer pipes 70 protrude downwardly
from the oblique plates 68 by a preset distance, and as
described above preferably have a length shorter than the
first fluid transfer pipes 57 of the first activating devices
C1 and C2.
The gas ascended from the lower chamber of the second
reactor 40 is gathered around the second fluid transfer pipes
70 in the same process as in the first activating devices
C1 and C2 to form second stay chambers V.
When a preset amount of the gas is gathered in the
second stay chambers V, the gathered gas is scattered in
all directions by the pressure of the second stay chambers
V so that the gathered gas pushes the sewage and wastewater
out of the second stay chambers V.
Thus, the gas pushed the wastewater from the second
stay chambers V is injected into the second fluid transfer
pipes 70 by the same process as in the first activating devices
so that solids contained in the sewage and wastewater may
be separated into high density solids and low density solids.
Since the second activating devices C3 and C4 have
the block shape, the solid-liquid separation and agitation
occur in every unit reactors differently from in the first
activating devices.
Therefore, it may be considered that uniform mixing
CA 02771637 2012-03-12
may be achieved by the solid-liquid separation and the
agitation in the entire second activating devices.
The sewage and wastewater and the gas ascended after
passing through the second activating devices C3 and C4 may
be discharged to the outside through a gas discharging hole
49 on the top and a treated water discharging hole 51 of
the second reactor 40.
As described above, the sewage and wastewater and the
gas sequentially pass through the anaerobic reaction
activating devices CI, C2, C3, and C4 including the first
activating devices C1 and C2 and the second activating devices
C3 and C4 and ascend up so that the solid-liquid separation
and the agitation may be carried out.
Since the solid-liquid separation and the agitation
are repeated, the treated water is in the upper chamber of
the second reactor 40 and the solids and microorganism are
concentrated in the lower chamber. Thus, the treated water
and the microorganism and solids are separated repeatedly
in every stage so that flow in a plug flow reactor (PFR)
may be maintained.
As described above, the first activating devices C1
and C2 are plates and the second activating devices C3 and
C4 are blocks so that the anaerobic treatment process may
be carried out in various ways.
Thefirstfluidtransferpipes57of the first activating
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devices C1 and C2 are longer than the second fluid transfer
pipes 70. The first activating devices Cl and C3 are higher
than and stacked in layers more than those of the second
activating devices C3 and C4.
Thus, the gas and the wastewater ascending in the second
reactor 40 undergo different agitations and separation
process while passing through the first and second activating
devices Cl, C2, C3, and C4 with different shapes and a
relatively large amount of gas is supplied from the lower
chamber to the upper chamber so that a relatively large amount
of treated water flows from the lower chamber to the upper
chamber so that agitation efficiency may be improved.
The first and second activating devices Cl, C2, C3,
and C4 may have various shapes.
Referring to FIG. 4 again, the gas circulation unit
43 is provided at a side of the second reactor 40 to supply
the gas filled in the first stay chambers V in the lower
chamber of the second reactor 40 into the upper chamber of
the second reactor 40 so that a rapid agitation may occur.
The gas circulation unit 43 includes first to fourth
pipes L1, L2, L3, and L4 communicated with the stay chambers
V of the second reactor 40, a fifth pipe L5 connected to
the top of the second reactor 40, a sixth pipe L6 connecting
the first to fifth pipes Ll, L2, L3, L4, and L5 and first
to fifth valves Si, S2, S3, S4, and S5 provided in the first
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CA 02771637 2012-03-12
to fifth pipes Li, L2, L3, L4, and L5 to open and close the
first to fifth pipes Li, L2, L3, L4, and L5.
Since the gas circulation unit 43 does not require
a powered device such as a pump discharging gas, the gas
can be circulated without power transmission.
That is, since hydraulic head by the sewage and
wastewater filled in the first reactor exerts in the stay
chambers V of the first reactor, the gas gathered in the
stay chambers V of the lower chamber may be easily supplied
in the stay chambers in the upper chamber by the hydraulic
head when the valves Si, S2, S3, S4, and S5 are opened.
The first to fifth valves Si, S2, S3, S4, and S5 may
include solenoid valves.
In the gas circulation unit 43, when the gas gathered
in the lower chamber is supplied into the upper chamber to
circulate, the first to fifth valves Si, S2, S3, S4, and
S5 are properly open and closed such that the gas may be
circulated into the upper chamber through various paths.
That is, all the first to fifth valves S1, S2, S3,
S4, and S5 are open so that gases in every stage maybe supplied
into the upper chamber or only the first and second valves
Si and S2 are open such that the gas gathered in the lowermost
stay chambers may be supplied into the stay chambers of the
directly upper chamber.
Otherwise, only the first and third valves Si and S3
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are open such that the gas gathered in the lowermost stay
chambers maybe supplied into the stay chambers of the directly
upper chamber.
As such, in a case when the first to fifth valves S1,
S2, S3, S4, and S5 are properly open and closed to discharge
the gases in the lower chamber of the second reactor 40 and
to supply the gases into the upper chamber of the first reactor,
the sewage and wastewater in the upper chamber is rapidly
transferred into the lower chamber to fill the space occupied
by the gas such that the gases and the sewage and wastewater
may be mixed with each other.
Simultaneously, highdensitysolidsandmicroorganisms
may be transferred down first. Then, when the sewage and
wastewater in the lower chamber is transferred into the upper
chamber due to the generated gas so that low density material
is transferred into the upper chamber first and the secondary
solid-liquid separation is carried out.
That is, the gas in the lower chamber of the second
reactor40isdischargedperiodicallyoracycle ofdischarging
the gas is adjusted according to the state of the agitation
and the solid-liquid separation so that the gas and the sewage
and wastewaterare effectivelymixedwitheachother,agitated,
and/or the solid-liquid separation occurs in the second
reactor 40.
The first activating devices and the second activating
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devices have some similar functions. However, since the
solid-liquid separation and the agitation in the second
activating devices are carried out voluntarily (so, it is
difficult to control) in the reactor but the solid-liquid
separation and the agitation in the first activating devices
may be controlled arbitrarily according to operating
conditions so that various conditions may be made during
the operation without applying the various conditions to
early design conditions, the first activating devices and
the second activating devices are vital elements in the
anaerobic treatment.
No matter what there are so many kinds of the sewage
and wastewater beyond time and space, the apparatus is just
installed and maintains only the fixed condition.
Thus, since type and amount of the sewage and wastewater
generated during theoperationdifferentfromtheearlydesign
may be changed variously, it must be required a compensation
device to cope with this situation.
As described above, the sewage and wastewater and the
gas may be separated into the solids and the treated water
or mixed with each other during the passing through the first
and second activating devices CI, C2, C3, and C4. When the
gas circulation unit 43 is driven, a great deal of gas is
discharged from the lower chamber into the upper chamber
of the first reactor. At this time, in order to fill the
CA 02771637 2012-03-12
empty chamber, the treated water in the upper chamber of
thefirstreactorisrapidlytransferredintothelowerchamber
so that the secondary mixing is carried out and the agitation
effect may be increased.
In spite of the gas circulation unit 43 disposed at
the side of the second reactor 40, the present invention
is not limited thereto, but another gas circulation unit
78, as illustrated in FIG. 9, maybe disposed at the opposite
side of the second reactor 40.
In the first activating devices Cl and C2 or the second
activating devices C3 and C4, the gases gathered in the stay
chambers V near the fluid transfer pipes 34 and 52 in the
vicinity of the gas circulation unit 78 may be easily
discharged out into the gas circulation unit 43, but the
gases gathered in the stay chambers Vat the relatively central
region of the second reactor 40 are hardly discharged because
a long distance from the gas circulation unit 43.
Therefore, another gas circulation unit 78 may be
disposed at the opposite side of the second reactor 40.
As such, by disposing the gas circulation unit 78 at
the opposite side of the second reactor 40, the gases gathered
at the central region of the second reactor 40 may be also
easily discharged out through the gas circulation units 43
and 78.
The pair of circulation units 43 and 78 or more may
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be disposed at the second reactor.
Meanwhile, as illustrated in FIG. 4, a circulation
device 45 circulating the gas and the sewage and wastewater
from the lower chamber to the upper chamber in the second
reactor 40 and vice versa is selectively mounted to a side
of the second reactor 40.
The circulation device 45 includes a pipe L wherein
the pipe L communicates the upper chamber of the second reactor
40 with the lower chamber. A circulation pump P is disposed
in the pipe L.
When the circulation pump P is driven, the sewage and
wastewater and/or the solids stored in the upper chamber
of the second reactor 40 are suctioned into the pipe L and
are discharged out into the lower chamber so that the sewage
and wastewater and the solids stored in the upper and lower
chambers of the second reactor 40 are circulated.
When this circulation is performed at a preset period,
pH of the first reactor is controlled (such as high pH of
the upper chamber of the first reactor and low pH of the
lower chamber thereof) and the sludge deposited in the
anaerobic reaction activating devices C1, C2, C3, and C4
is circulated.
An accumulation preventing unit 80 is disposed at the
lower side of the second reactor 40 to prevent the deposited
solids from being accumulated in the bottom of the second
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reactor 40.
The accumulation preventing unit 80 includes a seventh
pipe L7, connected to a lower side of the second reactor
40, into which the sewage and wastewater is introduced and
a discharge pump P2 connected to theseventhpipeL7togenerate
a suction force.
When the discharge pump P2 is driven, the deposited
solids and the sewage and wastewater in the lower chamber
of the second reactor 4 0 are discharged out through the seventh
pipe L7 so that the sol ids maybe prevented f rombeing deposited
in the lower chamber of the second reactor 40.
Following experimental data are obtained as a result
of treating the sewage and wastewater in the main treatment
unit 4.
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[Table 1]
Conventional Present invention
Treated amount of foods 17-18 30-60
(ton/day)
Stayed time (day) 26-27 7-12
Gas per ton (m3/ton) 30-40 90-120
Methane content (%) 60-65 70-75
Operating temperature 35-37 35-37
( C)
Efficiency (%) 40 85
As seen from the experimental data, the apparatus of
the present invention exhibits about two times treated amount
of foodbytheexistingapparatus. Inaddition, the apparatus
ofthepresentinvention hasaboutfourtimesgeneratedmethane
gas of the existing apparatus.
Consequently, the apparatus of the present invention
achieves efficiency higher than two times efficiency of
treating sewage and wastewater of the existing apparatus.
The exemplary embodiments of the present invention
are provided for the easy description and understanding of
the present invention with specific examples but do not limit
the scope of the present invention. It will be appreciated
by those skilled in the art that various changes and
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modifications may be practiced without departing from the
spirit of the present invention.
