Note: Descriptions are shown in the official language in which they were submitted.
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The present invention is directed to the treatment
of waste water, such as domestic or industrial sewage.
Waste water contains a variety of contaminants
including biodegradable carbonaceous material, nitrogenous
material which is mainly ammoniacal or other non-nitrate and/
or non-nitrite form and phosphate material and such contamin-
ants must be removed before the waste water can be reused.
In prior art systems, these contaminants have been
removed by biological oxidation of carbonaceous materials,
biological conversion of non-nitrate and/or non-nitrite
nitrogen to nitrate and/or nitrite forms (nitrification)
followed by respiratory reduction to nitrogenous gases in
the presence of a carbon source tdenitrification) and
chemical treatment of phosphate.
The carbon, nitrogen and phosphorus removals have
been carried out in separate reactors, leading to time-
consuming operations, owing to the inability of the prior
art to provide differing sets of conditions within the same
treatment unit.
The present invention provides a method for the
treatment of waste water containing contaminants including
dissolved biodegradable carbonaceous material and nitrogenous
material mainly in non-nitrate and/or non-nitrite form by
biological consumption and conversion to gases using a
single mixed microbial sludge. The method consists of a
plurality of interlinked steps in which there are established
a first reaction zone consisting of a first upright reaction
tank containing liguor, a second reaction zone physically
separate from but fluidly interconnected with the first
reaction zone and consisting of a second upright reaction
tank containing liquor, and a sludge separation zone physical-
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ly separate from both the first and second reaction zones but
!`~ fluidly interconnected with the second reaction zone and
consisting of an upright sludge separator tank containing
liquor.
The waste water is fed to the first reaction zone
and is passed as mixed liquor in association with the single
mixed microbial sludge successively through the first and
second reaction zones and the sludge separation zone along
a first flow path which extends from an inlet communicating
with the level of liquor in the first reaction tank, down-
wardly within the first reaction tank into communication
with an outlet from the first reaction tank, from the first
reaction tank outlet to an inlet communicating with the
level of liquor in the second reaction tank, downwardly
within the second reaction tank into communication with an
outlet from the second reaction tank, from the second reaction
tank outlet to an inlet communicating with the level of
liquor in the sludge separation tank, and downwardly within
the sludge separation tank into communication with a clarified
; 20 liquor outlet from the sludge separator tank.
The mixed liquor is recycled at a suspended solids
concentration in each of the reaction zones of about 3000
to about 7000 mg/l within each reaction zone to maintain the
mixed liquor substantially in suspension in each of the
first and second reaction zones.
Mainly anaerobic conditions in the first reaction
zone are established and maintained in the first reaction
zone for conversion of nitrate and/or nitrite nitrogen to
nitrogen ga8 and consumption of carbonaceous material in
the conversion. Mainly aerobic conditions are established
and maintained in the second reaction zone for conversion
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of nitrogenous material to nitrate and/or nitrite nitrogen
and oxidation of carbonaceous material.
The steps of internal recycling and establishing
the anaerobic and aerobic conditions in the respective
reaction zones are effected by establishing a second flow
path within each of the reaction tanks from the bottom
of the respective tank to above the liquid level therein,
passing a molecular oxygen containing gas into the second
flow path in each of the reaction zones adjacent the lower
end thereof at a rate at least sufficient to convey mixed
liquor upwardly along the second flow path and maintain the
mixed liquor in suspension in each of the tanks, controlling
the rate of flow of the gas into the second flow path of the
first reaction tank to provide a dissolved oxygen concentra-
tion in the waste liquor at the upstream end of the first
flow path which is less than about 0.5 mg/l and is capable
- of sustaining aerobic reactions only for an initial and
short portion of the first flow path through the first reac-
tion tank, and controlling the rate of flow of the gas into
: 20 the second flow path of the second reaction tank to provide
a dissolved oxygen concentration in the waste liquor at the
upstream end of the first flow path within the second
reaction tank which is at least about 2 mg/l and capable
.: of sustaining aerobic reactions for the major portion of
the first flow path through the second reaction tank.
Mixed liquor is recycled directly from the second
:: reaction zone to the first reaction zone at a flow rate
greater than the flow rate of waste water to the first
reaction zone by establishing a third flow path directly
from the bottom of the second reaction tank to above the
liguor level in the firot reaction tank, and passing a
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molecular oxygen containing gas into the third flow path
adjacent the lower end thereof at a rate sufficient to
convey the mixed liquor from the second reaction tank to
the first reaction tank at a flow rate greater than the
flow rate of waste liquor into the first reaction tank.
The dissolved oxygen concentrations in the first
and second reaction zones are controlled to provide a
dissolved oxygen concentration in the mixed liquor entering
the third flow path for recycle from the second reaction
tank to the first reaction tank which is approximately the
same as the dissolved oxygen concentration in the mixed
liquor at the upstream end of the first flow path in the
first reaction tank and a dissolved oxygen concentration
in the mixed liquor at the downstream end of the first flow
path in the first reaction zone which is less than about
0.1 mg/l.
Gas formed in the first and second reaction zones
are vented. During passage of treated waste water along the
first flow path within the sludge separation tank, suspended
sludge is at least partially flocculated, separated and
settled from the treated waste water.
Settled sludge is recycled directly from the sludge
separator tank directly to the second reaction zone at a
flow rate greater than the flow rate of waste water to
the first reaction zone and at a rate at least sufficient to
prevent anaerobic decomposition of the sludge in the sludge
separation zone by establishing a fifth flow path directly
from the bottom of the sludge separator tank to above the
liquor level in the second reaction tank, and passing a
molecular oxygen containing gas into the fifth flow path
adjacent the lower end thereof at a rate sufficient to draw
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the settled sludge into the fifth flow path and convey the
! same to the second reaction tank at a flow rate greater than -
the flow rate of waste liquor into the first reaction tank.
Clarified and treated liquor is removed from the
sludge separation zone at a rate which is the same as the
rate of feed of waste water to the first reaction zone.
The removed liquor may be subjected to chemical treatment
to remove phosphorus contaminants and other treatments, as
desired.
The present invention, therefore, effects the
manipulation of biological oxidation of carbonaceous material,
nitrification and denitrification within the same treatment
unit using a single sludge in a symbiotic two-step process
combined with sludge separation and recycle procedures.
The present invention also includes apparatus for
effecting such process. Accordingly, the present invention
also provides an apparatus for the treatment of waste water
containing contaminants including dissolved biodegradable
carbonaceous material and nitrogenous material mainly in
non-nitrate and/or non-nitrite form by biological consump-
tion and conversion to gases using a single mixed microbial
sludge, which comprises: a first reaction tank; a first
inlet to the first reaction tank for the inlet of waste
water to the first reaction tank; an outlet from the first
reaction tank connected to a first inlet of a second
reaction tank for feed of liquor to the second reaction tank
from the first reaction tank; a first outlet from the second
reaction tank connected to an inlet of a sludge separator
tank for feed of liquor from the second reaction tank to
the sludge se~arator tank, a first outlet from the sludge
separator tank for the discharge of treated waste water,
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a second outlet from the sludge separator tank connected to
a second inlet of the second reaction tank for recycle of :-
flocculated sludge from the sludge separator tank to the
second reaction tank and first means for effecting the
recycle, a second outlet from the second reaction tank
connected to a second inlet of the first reaction tank for
recycle of mixed liquor from the second reaction tank to
the first reaction tank and second means for ~ffecting the
latter recycle, means for recycling mixed liquor within the
first reaction tank, means for recycling mixed liquor within
the second reaction tank, means for feeding controlled quan-
tities of oxygen to the first reaction tank to establish
; and maintain predominantly anaerobic conditions therein, and
means for feeding controlled quantities of oxygen to the
second reaction tank to establish and maintain predominantly
aerobic conditioos ther~in.
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The invention is described further, by way
of illustration, with reference to the accompanying drawings,
in which:
Figure 1 is a schematic representation of a flow
sheet of a waste water treatment plant in accordance with
the present invention;
Figure 2 is a schematic sectional view of the
carb~n and nitrogen removal unit of the treatment plant
of Figure l; and
Figure 3 is a plan view of the clarifier unit.
Referring first to Figure 1, there is illustrated
a waste treatment plant 10 comprising a number of renovation
steps for the removal of contaminants from the waste water.
Raw ~ sewage, or,other waste mate~ial to be treated,
is fed by line 12 to a gross solids screen 14 for the removal
of gross solids which are collected by line 16 for disposal. 3
Any desired form of screen may be used. If desired, the gross
solid screen 14 may be omitted.
Raw screened sewage then is fed by line 18 to an
integrated carbon and nitrogen treatment unit 20, described
in more detail be]ow with reference to Figures 2 and 3,
wherein carbonaceous material and nitrogenous material
together with some phosphate material, are removed by
biological reaction of oxidation and reduction with activa-
ted sludge and air fed by line 22 and by cell growth.
The raw screened sewage passes by line 18 to a
first reactor tank 24, by line 26 to a second reactor
tank 28 and by line 30 to a sludge separator 32 before discharge
of carbonaceous material- and nitrogenous material-
depleted water from the treatment unit 20 by line 34.
Within the treatment unit, settled activated
sludge is recycled from thesludge separator 32 to the second
reactor 28 by line 36 and mixed liquor solids are recycled
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from the second reactor 28 to the first reactor 24 by line 38.
The treated water in line 34 is contactëd with alum
fed by line 40 in a chemical treatment tank 42 to cause
deposition of phosphate. The chemical treatment tank 42 may
take the form described in U.S. Patent No. 4,008,159. As
described in this U.S. Patent, chemical treatment to remove
phosphorus is effected by feeding a mixture of water containing
phosphorus materials and alum into a rotating fluidized bed
of chemical sludge, chemically coagulating the phosphorus
material within the fluidized bed, recycling liquor from the
fluidized bed to the feed mixture to maintain the fluidized
bed and separating treated liquid from the fluidized bed.
In this procedure, the amount of alum added and the recycle
ratio are dependent on one another. Optimum phosphate
removal has been found to occur with a recycle ratio between
about 1:1 and 1:3 and an alum feed of about 180 to 200 mg/l.
Any excess sludge formed in the treatment unit 20
is allowed to overflow from the sludge separator 32 with the
liquor in line 34 into the chemical treatment tank 42 and is
collected therein along with the chemical sludge produced
from the alum treatment.
The sludge collected in the chemical treatment
tank 42 is periodically or ntinuously removed by line 44
into a sludge thickener 46. Liquor separated from the sludge
thi~kener 46 may be cycled to the treatment unit 20 by line
4~, particularly to the first reactor 24. Alternatively,
the separated liquor may be passed by line 49 to the sludge
separator 32, the choice of feed by line 48 or line 49
depending on the water quality of the liquor. Waste sludge
1 30 is removed by line 50 for disposal.
The chemically treated liquor is passed by line 51
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to an ozone treatment column 52 to which ozone is fed by
line 54 for~removal of further contaminants before
passage by line 56 to a filtration bed 58 for removal of
suspended solids.
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The filtration bed may he backwashed
from time to time to remove accumulated solids.
The backwash effluent may be stored and forwarded to the
chemical treatment tank 42 during operation of the waste
treatment plant 10.
Purified liquid from the carbon filter bed 58
may be passed to storage or by line 60 to a disinfection
tank 62 to which ozone is fed by line 64, before discharge
of the effluent by line 66.
Turning now to consideration of Figure 2, which
illustrates in more detail the treatment unit 20, each of
the tanks, namely the first reactor 24, the second reactor
28 and the sludge separator 32, is in the form of an upright
cylindrical tank having a frusto-conical
insert at the lower portion thereof to avoid the accumu-
lation of sludge in thebottom corners of each tank.
The first reactor tank 24 has an inverted funnel
110 located therein separating the tank 24 into a first
zone 112 located between the inner wall of tank 24 and the
outer surface of the inverted funnel 110 and a second zone
114 located within the funnel 110 and communicating with
the first zone 112 only at the lower end of the funnel 110.
A liquor flow path through the first reaction tank 24,
therefore, is established downwardly through the first
zone 112 from thescreened raw sewage inlet 18 and upwardly
through the second zone 114 to the discharge pipe 26 communi-
cating with the neck 116 of the inverted funnel 110.
A pipe 118 extends axially of the inverted funnel
110 through the neck 116 and the second zone 114 to a loca-
tion adjacent the bottom of the tank 24.
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A pair of arms 120, 122 extend radially-of the
. reaction tank 24 from the upper end of the pipe 118 to a
location adjacent the inner wall of the tank 24 where
they communicate with discharge pipes 124, 126 located
adjacent the intended liquid level in the first zone 112.
The pipe 118, arms 120, 122 and discharge pipes
124, 126 establish a flow path from the lower end of the
tank 24 to the upper portion of the first zone 112 out of
fluid flow communication with the second zone 114 other
than at the lower end of the pipe 118.and allows internal
recycle of the mixed liquor in the tank 24.
A second axial pipe 128 extends through the pipe
118 to the lower end thereof and is used to convey air or
another oxygen-containing gas into the tank 24 at the lower
end of the pipe 118 to maintain the internal liquor recycle. - .
The second reactor tank 28 has a cylindrical
sleeve 130 extending axially of the tank 28 defining
a first zone 132 located between the inner
wall of the tank 28 and the outer surface of the sleeve
130.
A liquor flow path through-the second reaction
tank 28, therefore, is established downwardly through the
first zone 132 from the inlet pipe 26 to the discharge pipe
30 which extends to the lower end of the sleeve l30~Liquor flow
through the combination of the two reactor tanks 24 and 28
therefore passes downwardly from the sewage entrance pipe
18 around the outside of the inverted funnel 110, upwardly
to the discharge pipe 26 inside the inverted funnel 110, and
downwardly from the entrance pipe 26 around the outside of
the sleeve 130 to the discharge pipe 30 inside the sleeve 130.
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If desired, the second reaction tank 28 may be
provided with an inverted funnel identically to the tank 24
with the discharge pipe 30 communicating with the upper end
of the inverted funnel.
A pipe 136 extends axially of the sleeve 130 from
the top thereo~ through the internal zone 13~ of ~ sleeve 130 to
adjacent the bottom of the tank 28. A pair of arms 138
and 140 extend radially of the reaction tank 28 from the
upper end of the pipe 136 to a location adjacent the inner
wall of the tank 28 where they communicate with discharge
pipes 142 and 144 located adjacent the intended liquid
level in the first zone 132.
The pipe 136, arms 138, 140 and discharge pipes
142, 144 establish a flow path between the lower end of the
tank 28 to the upper portion of the first zone 132 out of
fluid flow communication with the internal zone 134 other
- than at the lower end of the pipe 136 and allows internal
recycle of mixed li~uor in the tank 28.
A second axial pipe 146 extends through the pipe
136 to the lower end thereof and is used to convey air or
other molecular oxygen-containing gas into the tank 28 at
the lower end of the pipe 136 to maintain the internal
liquor recycle.
; A third pipe 148 extends downwardly internally
of the sleeve 130 in parallel fashion to the pipe 136 to
a location adjacent the lower end of the tank 28 and
communicates at its other end with recycle pipe 38 exten~
ding to the first tank 24. The third pipe 148 and the
pipe 38 establish a flow path from the lower end of the
-30 second tank 28 to the upper portion of the first zone 112
in the first tank 24 for recycle of mixed liquor from the
second tank 28 to the first tank 24.
A fourth pipe 150 extends axially of the pipe
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148 to adjacent the lower end thereof to feed air into the
pipe 148 to achieve an air lift of mixed liquor along the
recycle flow path from the second tank 28 to the first tank
24.
The slu~ge separator tank 32 has an inverted funnel
152 located therein separating the clarifier into zones to
establish a flow path of liquor from the inlet pipe 30
first downwardly between the outer wall of the inverted
funnel 152 and the inner wall of the tank 32 and then
upwardly internally of the inverted funnel to the outlet
pipe 34.
A pipe 154 extends axially of the inverted funnel
152 through the neck 156 to a location adjacent the bottom
of the sludge separator tanlc 32. The pipe 154 communicates
at its upper end with recycle pipe 36, so that pipes 154
and 36 establish a flow path between the lower end of the
tank 32 and the upper portion of the first zone 132 in the
: second reaction tank 28 for the recycle of settled sludge
to the second reaction tank 28.
A second axial pipe 158 extends internally of the .
, pipe 154 to a location adjacent the lower end thereof to
, feed air into the pipe 154 to air lift settled sludge along
, the recycle flow path from the clarifier tank 32 to the
second reaction tank 28.
. The sludge which passes through the treatment
unit 20 is a bulking sludge which is a combination of
filamentous organisms and nitrogen gas bubbles contained ~ :within the mixed liquor. It was found that gentle stirring
of the mixed liquor enhanced settling by producing coagula-
tion of sludge particles to a heavier mass. It is preferred :
,' to provide the inflowing liquor to the sludge separator tank 32
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as a slowly rotating mass outside the inverted cone 152
to improve flocculation of the sludge around the inverted
cone 152 and in~rease the settleability of the sludge. A
typical rotation speed is about 1.5 rpm.
As may be seen from the plan view of Figure 3,
rotation of the liquor within the clarifier tank 32 may
be achieved by separating the incoming feed in line 30
into three separate streams 160, 162 and 164 which are
discharged around the outside of the cone 156 in approxi-
mately tangential manner.
While the construction and operation of the slu~geseparator tank 32 as described above has particular utility
for handling bulking sludge in the two-tank treatment opera-
tions of tanks 24 and 28, such a sludge separator tank 32
operation may be used to aid in the settling of bulking sludge
obtained from any biological treatment procedure, for example
that described in U.S.Patent No.3,980,556, especially in the
absence of added activated carbon.
In the operation of the treatment unit 20,
sewage or other waste water fed by line 18 to the first
reaction tank 24 is mixed with recycled mixed liquor from
the second tank 28 and with internally recycled oxygenated
mixed liquor. The recirculation rate of mixed liquor
within the tank 24 is sufficient to màintain
sludge mainly in suspension within the tank 24.
The recirculation rate of mixed liquor from the
second tank 28 is greater than the rate of flow of external
liquor into the tank 24 by lines 18 and 48 to ensure that
all the introduced liquor passes through the two tanks
and is subjected to treatment.
The dissolved oxygen in the liquor at the top
of the zone 112 and oxygen picked up by the splashing of
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the recycle streams into the liquor in the first tank 112
to provide a momentarily higher dissolved oxygen content,
is sufficient initially to sustain aerobic reactions,
including conversion of ammoniacal nitrogen to nitrate and/
or nitrite, nitrogen and conversion of carbonaceous
material to carbon dioxide. Typically, the dissolved
oxygen concentration value at the top of the zone 112 is
about 0.5 mg/l.
As the liquor moves downwardly through zone 112,
the oxygen available for aerobic reactions rapidly is
diminished and anaerobic conversion of nitrate and/or
nitrite nitrogen to nitrogen gas with consequent consump-
tion of dissolved carbon co~mences, resulting in a typical
-dissolved oxygen concentration at the lower end of the
tank of less than 0.1 mg/l.
Anaerobic reactions predominate in the reaction
tank 24 and these reactions combined with cell growth
deplete the carbonaceous material content of the incoming
sewage substantially completely. Cell growth also accounts
for some nitrogen and phosphorus removal. Some mixed liquor
is recycled within the tank 24 by pipe 118 and this re-
cycled mixed liquor is oxygenated during the recycle to
provide the required dissolved oxygen in the mixed liquor
and mixing of the mixed liquor. Gases formed in the first
j reaction tank 24 are vented.
Mixed llquor overflowing from the tank 24 to the
second tank 28 having a low dissolved carbonaceous material
content but still containing the bulk of the ammoniacal
nitrogen of the initial sewage, is mixed with recycled
settled sludge from the sludge separator 32 and internally
recycled oxygenated mixed liquor to form a mixed liquor
; having a high dissolved oxygen concentration at the top of
the zone 132.
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The rate of return of sludge from the sludge
separator 32 is determined by the hydraulic flow to the
sludge separator 32 required to maintain the slow rotation
in the tank 32 to achieve flocculation.
The rate of recycle of mixed liquor within the
reaction tanX 28 is considerably higher than that within
the tank 24 owing to a higher dissolved oxygen concentration
requirement in the tank 28 and serves to maintain the
sludge in suspension within the tank 28.
In the tank 28, the dissolved oxygen concentra-
tion of the mixed liquor at the top of zone 132 should be
sufficient to establish mainly aerobic conditions with
zone 132. Typically, the dissolved oxygen concentration
i8 in excess of 2 mg/l.
The aerobic conditions predominating in tank 28
result in conversion of the ammoniacal nitrogen to nitrate
and/or nitrite nitrogen until the oxygen level is in-
sufficient to sustain aerobic conditions and anaerobic reac-
tions occur. The dissolved oxygen concentration of the
mixed liquor recycled by pipe 38 to the first reaction
tank 24 preferably is approximately that of the mixed
liquor at the top of the zone 112 in tank 24, typically
about 0.5 mg/l.
In the two reaction tank system used in the
illustrated embodiment of the invention, the contaminants
in the incoming sewage are subjected to a symbiotic process
with a single sludge in which the contaminants are subjected
first to aerobic reactions for a short period and then to
anaerobic reactions in the tank 24 and second to aerobic con-
ditions for a long period and then to anaerobic conditions
in tank 28, with recycling from tank 28 to tank 24 to
deplete nitrate and/or nitrite nitrogen. In this way, in
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combination with sludge cell growth, carbonaceous material
and nitrogenous material contaminants are depleted.
Phosphate material also is removed by sludge cell growth.
The mixed liquor from the second reaction tank
28 overflows into the sludge separator 32 wherein settling
of sludge occurs allowing a supernatant clear effluent to
be removed by line 34. Periodic wasting of sludge from
the system is necessary and this is achieved by allowing
sludge to overflow with the effluent in line 34 to the
chemical treatment tank 42 from which it is removed with
chemical sludge by line 44 to the sludge thickener 46.
Alternatively, sludge may be wasted from the sludge
separator tank 32 by using a sludge pump operably connected
to the tank 32 or recycle line 36.
The mixed liquor concentration throughout the system
of the first and second reaction tanks 24 and 28 is substan-
tially uniform and varies from about 3000 to 7000 mg/l,
preferably in the range of about 4000 to 5000 mg/l. The
corresponding MLVSS values are 2500 to 6000 mg/l and pre-
ferably 3400 to 4500 mg/l.
The treatment unit 20 removes about 0.006 to
about 0.057 lb of ammoniacal nitrogen from sewage per lb
MLVSS per day, preferably about 0.02 lb NH3-N/lb/MLVSS/day,
about 0.011 to about 0.054 lb of total nitrogen per lb
MLVSS per day, preferably about 0.031 lb TN/lb MLVSS/day,
and about 0.017 to about 0.112 lb SOC/lb MLVSS/day,
preferably about 0.040 lb SOC/lb MLVSS/day.
- - The treatment unit 20 operates effectively in
the absence of added activated carbon and it has been found
that the presence of added activated carbon has little or
no effect on the removal of contaminants, although such
activated carbon presence may improve the settleability
of the sludge.
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Exam~le I
A waste treatment system as illustrated in Figure
1 was operated continuously under pilot plant conditions
over a period of sixteen weeks treating domestic sewage
from an adjacent housing subdivision. No activated carbon
was added to the system. The dimensions of the units of
the system are set forth in the following Table I:
TABLE I
Vnit Height ~ft) Diameter Effective
Total Effective (ft) 3volume
ft USG
.
Reactor 24 10.0 9.5 6.5 2742050
Reactor 28 10.0 9.5 6.5 2742050
Separator 32 10.0 9.5 6.5 132987
Chemicaltrea ~ nt 42 10.0 8.8 6.5 265 1984
Ozone col.52 15.0 15.0 0.3 3 22
Filter 56 10.0 6.0 2.0 32236
Disinfection 62 15.015.0 2.0 47353
Thickener 46 10.6 9.7 4.0 122912
Flow rates of liquor through the system and air
flows are set forth in the following Table II:
TABLE II
Flow Rate Air
` (USGPM) (SCFM2
Raw sewage line 12 7.5
Internal Recycle Reactor 24 60.0 5.0
I Reactor 28 to Reactor 24
I line 38 12.0 0.5
Sludge Thickener liquor
in line 48 or llne 49 - 2.0 0.25
Line 26 21.5
Internal Recycle Reactor 28 240.0 25.0
Separator 32 to Reactor 28
line 36 22.0 2.0
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1062380
TABLE II (Continued)
Flow Rate Air
(USGPM) (SCFM)
Line 30 31.5
Line 34 9-5
Input to chemical treatment 42 17.0 0~5
Chemical treatment 42 recycle 7.5
Line 51 7.5
Line 44 2.0
Line 56 7~5
Line 60 7.5
Line 66 . 7 5
.
During the test period, the water quality of
incoming sewage and final effluent were determined for
samples taken every 15 minutes for 24 hours a day.
Weekly means values for the various contaminants were
determined. These results appear in the following Table
.
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OD U~ n N 0~ 1~ O ~r 11 ~1 ~ ~ ~il
~r ~D U~
~ ~ O ~
E ~
~1 ~ I N O O O O O O O O O '~
OOoOOOoOOOOOOIO~0
I~Q~ ~ ~
Y _I _I ~ O ~ O O o o
_ O O O000000110 ~000 ~0
13 ~ ~ ~ o N ~ r u~ ~ ~ .
,_~ ~ o O oo o o _~ o o o I o o O ~1 N
H ¦ ~ ~ ~ N~ ~; ~ N N N ~ ~ ~ ~ o 1` N 3
~1 5 N ~1 ~1 o _I O O 0 ~3
OOOOOOIIIIIIOIOO Ul~
'ii ~ ~g
_I O O N O 11) ~ D ~ G ~
~ O O O O ~i 0 0 0 0 0 0 0 0 0 0 0
. J ~ 0~ I N 11~ ~ ~ O CO CO ~1 ,~
~D ~ O ~ D 11') CO 11 0 0
CO ~ O~ r N N ~ ~ ~
7~
~ o o UN~ aN~ U~ o
gl~ O O O O N ~ _i ~ ~i _i N N ~r N li U~
~ ~
~ N O _I O _I O ~;i N O --I _I O ~1 ~ N
~ OOOOOOOOOOIOOOO~
~r O _I ~ N 1` ~ ~ O~ N 111 ~D O ~ U7
~i ~ O N O ~ ~ O Cl ~1 J
N N N N ~ I I ~ ~ N ~ N ~ ~ ~
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106~380
Based on the data appearing in Tahle III,
efficiencies of removal of nitrogen, carbon and phosphorus
by the system were determined and the results appear in
the following Table IV:
.
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106Z380
1~ Cl~ D ~ ~ ~ N ~ U~
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~i ~ 1/~ 1~ O ~ 11 ~ N ~1
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~1 ~r 0 1~ 0 In ~ 1~ It) It~ 11~ ~ ~ el~ N
e ......... .....
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i 2 ~j~ ~ o o o o ,~
oooooooooIIooooo
r l ~ u~
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o~ o ~ u~ ~ ~ ~ ~
OO ~ _i 1~ ~ D CO ~ er ~ _i CO U~ ~r
o d
. . i ~ ~ o
., . !: ~ o ~ o~
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1062380
The mean3 removal efficiencies of 82.3~ for
nitrogen, 93.9~ for total organic carbon, 98.4~ for BOD5
and 97.7% for phosphorus represent very satisfactory
results.
Example II
During the period of the test results reproduced
in Example I, grab samples at twice weekly intervals also
were taken at the input in line 18, at the effluent from
the sludge separator in line 34, at the effluent from the
chemical clarifier in line 51 and at the final effluent in
line 66. During the same period, random determinations
were made in the two reaction tanks 24 and 28 of the
volatile suspended solids (MLVSS) concentrations, oxygen
uptake rates (OUR) and specific uptake rates (SUR).
The following Table V gives the volatile suspended
solids concentrations and uptake rates and Table VI gives
the weekly mean values for contaminants in the grab samples
at the various locations.
TABLE V
. _
Determina- MLVSS OUR SURReactor.28 .l:
. tion No. MLVSS~r . O~lb -:
. . .__ . .
1 4620 600.013 3800 60 0.016 .
2 3390 600.018 3390 60 0.018
3 3600 780.022 4580 72 0.016
. 4 3150 660.021 3080 60 0.019
; .... 5 289060 0.021 3130 64 0.020
- 18
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The results reproduced in this Example illustrate the
effect that the carbon and nitrogen treatment unit 20 and
the chemical treatment have in the overall sewage treatment
system of ~igure 1, the detailed results of which appear in
Example I.
EXAMPLE III
During the test period of Examples I and II, random
spot determinations of ammoniacal nitrogen, nitrate nitrogen
and soluble organic carbon were made at various locations
in the treatment unit 20. The following Table VII
reproduces these results:
- 20 - -
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1062380
The resulis of the above Table VII illustrate the
effect of the various components of the unit 20 on the in-
coming sewage.
Example IV
The procedure of Example I was repeated with addit--
ions of various quantities of activated carbon. Contaminants
were tested using,the continuous sampling (i.e. every 15
minutes) technique described in Example I and removal
efficiencies were determined. Mixed liquor concentrations
and uptake rates were also randomly determined.
The following Tables VIII and IX reproduce the
data obtained:
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106Z380
TABLE IX
Det~n~nation Reactor 24 Reactor 28
mg/l mg/l/hr Ib OJlb mg/l m~/l/hr lb O~/lb
MLVSS/hr MLVS~/hr
1 3270 90 0.028 3770 72 0.019
2 3260 93 0.029 3530 84 0.024
3 3850 102 0.026 3290 94 0.029 . -
4 3580 100 0.028 3700 98 0.026
4510 105 0.023 4320 83 0.019 .
6 3090 32 0.009 3560 68 0.019
_ 7 6680 57 0.009 ~380 15 0.003
Noke: Deb~n~nations Ncs.l bo S were made in weeks 1 an~ 2, debc~ration:
No. 6 was made inw~ek 3 and ~ebe~bnotion No.7 was ma~e inweek 5.
The mean removal efficiencies of 80.2% for
nitrogen, 93.3% for total organic carbon, 98.5% for BOD5
and 98.9% for phosphorus represent very satisfactory results
but do not differ significantly from the results set forth
in Example I in the absence of added activated ca~bon.
Example V
Based on the data contained in the above
Examples, design parameters for the process of this invention
can be compared with those of conventional activated sludge
process as set forth in the standard textbook by Metcalf
and Eddy, 1972. The comparison appears in the following
T ble X:
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The present invention, therefore, provides a
waste water treatment system in which two fluidly-
interconnected tanks and a single sludge are used to
achieve symbiotic anaerobic and aerobic operations to
remove nitrogenous and carbonaceous materials. Modifica-
tions are possible within the scope of the invention.
- 26
