Note: Descriptions are shown in the official language in which they were submitted.
2 1 96230
1546/168-12
METHOD AND DEVICE FOR SEWAGE CLARIFICATION
Backqround of the Invention:
Field of the Invention:
The invention relates to a method for clarifying any sewage
containing decomposable solid matter by means of continuous
sewage-treatment in physical processing stages equipped with
assigned solid matter separators in the form of a coarse-mat-
ter separator, a fine-matter separator as well as a down-
stream heavy medium separator with following flotation-stag-
es, from which solid-matter foam that has been developed by
using impact mixing valves or gas-water mixers, is separated.
The invention also relates to a device to performing the
method and an aerator for the sewage.
The known methods for sewage clarification which apply
several clarification processes in sequence, are mainly
executed at stationary plants. The structural configuration
of such plants is costly and they have a high space require-
ment as well as a dependence on steady solid matter and load
factors. Transportable devices generally are based on a
filtering technique extended by either chemical or biological
treatment. Therefore, the planned use thereof is limited to
one type of sewage. Each filtering technology, operating
individually or as the main emphasis, causes an increase of
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contamination in the neglected part. Physical filtering
techniques dissolve additional matter by abrasion or turbu-
lent flow. Biological clearing stages cause an increase of
physical water contamination in the form of dead and living
substances such as biomasses, sewage fungi and parasites.
Chemical clearing through additives, after a previous elimi-
nation of all other polluting materials to the greatest
possible extent, causes an extraordinary quantity of highly
contaminated waste.
When purposefully used in special ranges for special sewage
and operated as required, each method achieves good results.
However, a satisfactory total clearing, especially of differ-
ent types of sewage, in accordance with regulations regarding
clarified-water effluence, can not be achieved that way.
summarY of the Invention:
It is accordingly an object of the invention to provide a
method and a device for sewage clarification of any type of
sewage, which overcomes the hereinafore-mentioned disadvan-
tages of the heretofore-known methods and devices of this
general type, which is manufactured in series, is suitable
for use in a transportable device with a compact construction
or for stationary use in a modular structure, and has a
general process control which automatically adapts the
clearing methods in the case of new conditions to variable
sewage flow and changes in the sewage water contents.
''~ 2~ ~6-230
With the foregoing and other objects in view there is provid-
ed, in accordance with the invention, in a method for clari-
fying any sewage containing decomposable solid matter by
means of continuous sewage-treatment in physical processing
stages equipped with assigned solid matter separators includ-
ing a coarse-matter separator, a fine-matter separator and a
heavy medium separator with flotation-stages disposed down-
stream, from which solid-matter-foam having been developed by
using gas-water mixers or impact mixing valves is separated,
the improvement which comprises subjecting the sewage to an
aerobic and a downstream anaerobic sewage treatment with
repeated precisely controlled industrial process circulation
through assigned bypasses in individual clearing stages in
which sewage water suctioned off from the aerobic biological
clearing stage leads back together with a mixture of commer-
cial oxygen from a gas-water mixer and clear water into the
aerobic biological clearing stage; and monitoring the sewage
flow through the individual treatment stages with sensors and
feeding determined values to a process control unit for
processing with following flow control.
In accordance with another mode of the invention, there is
provided a mçthod which comprises additionally chemically
treating impurities such as in industrial waste with gas such
as commercial oxygen, to biological clearing.
4 2 1 96230
, ~ .~
In accordance with a further mode of the invention, there is
provided a method which comprises treating solids and foam to
reduce a final volume of sludge or disposable waste in an
additional biological clearing stage with aerobic and
anaerobic treatment and discharging wet solids for further
treatment or land fill.
With the objects of the invention in view, there is also
provided a device for clarifying any sewage containing
decomposable solid matter, comprising a reservoir, a clari-
fied water discharge basin, and a clarified water recirculat-
ing line leading from the clarified water discharge basin to
the reservoir, the gas-water mixers bypassing the clarified
water recirculating line.
In accordance with another feature of the invention, the fine
matter separator includes a cylindrical pipe carrying a
current in a given direction and having a wall with a multi-
plicity of holes and perforations formed therein a grid, and
a spiral brush rotating in the cylindrical pipe with helical
threads being narrower as seen in a countercurrent direction.
In accordancé with a further feature of the invention, the
aerobic biological clearing stage includes a vertically
standing hollow body having a bottom region, an upper part, a
top cover, an upper edge region, a sewage water supply
connected to the bottom region, a water discharge at the top
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cover or at the upper edge region, and a bypass connecting
the upper part with the bottom region.
In accordance with an added feature of the invention, the one
of the physical processing stages is a sedimentation basin,
and the sedimentation basin and the floatation stages are
part of an aquatritor.
In accordance with an additional feature of the invention,
the flotation-stages include a mixing basin in the form of a
four chamber system.
In accordance with yet another feature of the invention, the
biological clearing stages are combined into a bioreactor.
In accordance with yet a further feature of the invention,
there is provided an additional biological clearing stage
having means for aerobic and anaerobic treatment, for treat-
ing solids and foam to reduce a final volume of sludge or
disposable waste and discharging wet solids for further
treatment or land fill.
In accordance with further features of the invention, the
impurities are additionally chemically treated with gas,
preferably with commercial oxygen. Furthermore, the
impurities in industrial waste are treated with gas prior to
biological clearing, and preferably with commercial oxygen.
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,~t.
With the objects of the invention in view, there is addition-
ally provided a device for aerating sewage water, comprising
a closed vessel having an upper inlet for light medium, a
lower inlet for a fluidic mixture or blend, a feed pipe for
sewage water, and a cylindrical nozzle body communicating
with the light medium, the nozzle body having a nozzle base,
a nozzle trunk connected to the nozzle base, an axial through
bore in the nozzle base leading into a nozzle outlet chamber
in the nozzle trunk, and a nozzle tip or valve being disposed
on the nozzle trunk and defining an annular impact chamber
between the nozzle tip and the nozzle trunk leading into an
annular nozzle, the annular nozzle having a nozzle gap in the
shape of a truncated envelope of a cone being adjustable in
width and leading into the nozzle outlet chamber.
The device operating in accordance with the method of the
invention permits the recordation or logging of monitoring
data and permits a continuous operating sequence control
through data storage, data processing and remote data trans-
mission. Required chemicals can be metered and purposeful
added and thereby possibly resulting particular waste sludge
can be skimmed separately. The operating costs for the
method according to the invention are low, since the method
is carried out in a low-maintenance manner and all of the
components are low-wear or wear-free.
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.i .
In accordance with concomitant features of the invention, the
physical processing stages is a sedimentation basin, and the
sedimentation basin and the floatation stages are part of an
aquatritor. The flotation-stages preferably include a mixing
basin in the form of a four chamber system. It is furthermore
advantageous if the biological clearing stages are combined
into a bioreactor.
In accordance with yet a final feature of the invention, the
device includes an additional biological clearing stage
having means for aerobic and anaerobic treatment, for
treating solids and foam to reduce a final volume of sludge
or disposable waste and discharging wet solids for further
treatment or land fill.
Other features which are considered as characteristic for the
invention are set forth in the appended claims.
Although the invention is illustrated and described herein as
embodied in a method and a device for sewage clarification,
it is nevertheless not intended to be limited to the details
shown, since various modifications and structural changes may
be made therein without departing from the spirit of the
invention and within the scope and range of equivalents of
the claims.
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.
The construction and method of operation of the invention,
however, together with additional objects and advantages
thereof will be best understood from the following descrip-
tion of specific embodiments when read in connection with the
accompanying drawings.
Brief Description of the Drawinqs:
Fig. 1 is a diagrammatic view of a transportable device in a
compact construction;
Fig. 2 is a flowchart of the method in accordance with the
invention;
Fig. 3 is a fragmentary, longitudinal-sectional view of a
fine-matter separator;
Fig. 4 is a fragmentary, longitudinal-sectional view of an
aerobic biological clearing stage;
Fig. 5 a simplified view of an aerator;
Fig. 6 is a fragmentary, longitudinal-sectional view of an
aerator;
Fig. 7 is an enlarged view of a portion A of Fig. 6;
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, ...
Figs. 8 and 9 are respective longitudinal-sectional and
top-plan views of an aquatritor of the invention;
Fig. 10 is an enlarged and more detailed longitudinal-sec-
tional view of the aquatritor of Fig. 8;
Fig. ll is a longitudinal-sectional view of a bioreactor of
the invention;
Figs. 12 and 13 are respective top-plan and longitudinal-sec-
tional views of a four chamber system of the invention; and
Fig. 14 is a flow chart illustrating the operation of the
four chamber system with the bioreactors.
Description of the Preferred Embodiments:
Referring now in detail to the figures of the drawing, each
of which should be read with the flow chart of Fig. 2, and
first, particularly, to Fig. 1 thereof, there is seen a
reservoir 1 with a capacity of, for example, 30 cubic meters
together with a coarse-matter separator 2, which are connect-
ed upstream of a compactly constructed device for sewage
clarification. The sewage is supplied to the coarse-matter
separator 2 by a water conduit 3. The coarse-matter separa-
tor 2 advantageously is provided with a 3 to 5 mm grid. Asensor 4 sends values regarding a measured water level in the
reservoir 1 to a process control 22 and a pump 5 delivers the
21 96230
....
sewage through a pipe 6 to a fine-matter separator 8 provided
with a 1 to 2 mm grid, in a first region of the compactly
constructed installation. From there the sewage, which is
cleared of coarse matter, is delivered to a heavy matter
sedimentation basin 12, where heavy matter which is < 1 to 2
mm and is heavier than water, sinks down into a settling
shaft 14 from which they are regularly drained through a
waste valve 16, manually or through a process control. A
water level indicator 18 and a pH-meter 20 continuously
lo control water level and hydrogen ion concentration in the
heavy matter sedimentation basin 12 and transmit the values
to the process control 22 which logs and processes them and
other measured values. A lime and acid dosimeter 24 passes
amounts of substance determined by the process control 22
into the physically treated sewage. A waste pipe 26 passes
surplus sewage into the reservoir 1. A discharge basin 42 is
also shown.
The sewage is passed through a pipe 28 from the heavy matter
basin or separator 12 into a mixing basin 30 which is part of
a pre-flotation apparatus. Immediately before being led into
the mixing basin 30, aerated water is admixed to the sewage
by a first impact mixing valve or gas-water mixer 32, which
will be referred to below as a "tector". The tector 32
operates based on a bypass principle, it receives the mixed
water from a clear water discharge basin 34 of a reflotation
apparatus and it receives the air from a compressor 36. The
~ 2196230
water, which is enriched with air bubbles, flows through a
reactor chamber 38. In this way, solid matter foam precipi-
tations are generated on the surface which are pushed into a
first discharge conduit 40 by a foam skimmer, in a manner
which is process controlled and performed at regular time
intervals. The sewage is conducted into an aerobic biologi-
cal clearing stage 44 through a pre-flotation discharge basin
44. At this point, the sewage already has been cleared from
95 -99 ~ of all solid matter, so that essentially only
dissolved matter come to the biological clearing stages. The
effectiveness of the biological clearing stages is multiplied
by means of the thorough physical pre-clearing. Inside the
aerobic biological clearing stage 44, which is constructed as
a fluidized bed filter, the sewage is constantly suctioned
off by means of a pipe system 45, then brought back to the
clearing stage 44 by means of a pump 46 and a pipe system 47,
and is constantly supplied by a second tector 48 with commer-
cial oxygen from oxygen bottles 50 and mixed water from the
cleared water reflotation discharge basin 34. The sewage can
be circulated up to ten times per hour and reaches a control-
lable high oxygen enrichment which may be many times higher
than the normal degree of oxygen saturation. All tectors are
run in bypass operation to keep the decompression valves
operating troublefree. The dead biomass or bacterial mass,
which is in the aerobic biological clearing stage 44, is
precipitated at the surface in the form of solid matter foam
and is process-controlled and dredged in a time oriented
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21 q6230
manner into a second discharge conduit 52, preferable by a
chain desludger. Then the sewage is piped through a spillway
from the aerobic biological clearing stage 44 into an
anaerobic biological clearing stage 54. In this clearing
stage, a continuous sewage circulation takes place by means
of a pump 55 seen in Fig. 2 and a sensor 56 controls the
oxygen saturation or content.
After treatment in the anaerobic biological clearing stage
54, the sewage flows through a pipeline 58 into a mixing
basin 60 of the reflotation apparatus. Immediately before
flowing into the mixing basin 60, a clear water-air mixture
or blend is added to the sewage by a third tector 62.
Afterwards the sewage comes into a reflotation reaction
chamber 64 where a solid matter precipitation at the surface
again takes place. A sensor 66 controls the water level. A
desludger dredges the solid matter precipitation into a third
discharge conduit 68 in a time-oriented and process-con-
trolled manner. The clarified sewage flows from the reaction
chamber 64 into the reflotation clear water discharge basin
34 where a pH-value sensor 72 controls the hydrogen ion
concentration and further sensors 73 and 74 control the
oxygen saturation and the water temperature. A constant
levelling device 76 drains the clarified water flow into an
outlet pipeline 70 or through a valve 78 back into the
reservoir 1, in which the required clarified water is divert-
ed as mixing water for the impact mixing valves or gas-water
21 96230
mixers 32, 48 and 62, which are the first, second and third
tectors. The temperature of the clearing stages 44 and 54 is
kept constant by means of process-controlled immersion
heaters 80. The process control 22 supervises and logs all
of the measured values such as water level, oxygen, pH-values
and temperature, and furthermore operates the functions of
the pumps, the lime and acid dosimeter, the oxygen concentra-
tion, the valve cycles and the desludgers for solid matter
foams, and it gives a danger-signal and blocks the discharge
lo of possibly insufficiently clarified sewage in the case of an
emergency.
According to Fig. 3, the fine matter separator 8 is formed
mainly of a rotating spiral brush 11 which is concentrically
mounted in a cylindrical pipe 9. The spiral brush has an
inclination beginning at its lower free end and decreasing
towards its other end, at which a driving motor 19 with a
gear is disposed, i.e. the helical threads of the brush 11
continually become narrower in the direction of the upper
end. The wall of the cylindrical pipe 9 is equipped with a
multiplicity of holes and perforations formed in a non-illus-
trated grid, having an opening surface which is adapted to
the maximum particle size of the solid matter which is to be
separated.
The pipe 9 is concentrically disposed in a jacket pipe 13,
which is central~y equipped with a sewage water-intake
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21 q6230
chamber 21 having a sewage water-inlet pipe 15. The sewage
water-inlet pipe 15 is connected to the coarse-matter separa-
tor 2. The diameter of the jacket pipe 13 is selected in
such a way that a hollow space 27 between the jacket pipe 13
and the outer surface of the inner pipe 9 with its holes and
perforations guarantees a safe all-round distribution of the
sewage water supplied by the water intake chamber 21. The
hollow space 27 between the inner pipe 9 and the jacket-pipe
13 is sealed at a lower end 23 while the inner pipe 9 is open
at the lower end and serves as a water-outlet 25. In the
upper region of the inner pipe 9 and the jacket-pipe 13 a
sludge-drain 17 is provided on one side.
The sewage water is supplied through the water-inlet pipe 15
and the water intake chamber 21 into the hollow space 27
between jacket-pipe 13 and pipe 9 with its holes and perfora-
tions formed in a grid. The sewage water flows through the
holes and perforations of the pipe 9 into the region of the
rotating spiral brush 11 which is driven by the motor 19.
While the sewage water flows in the direction of the water-
outlet 25 at the lower open end of the pipe 9, the suspendedsolids, especially the fine matter, are held back by the
threads of the spiral brush and are transported upwards
through the threads which become more and more narrow. Due
to an increasing amount of solid matter between the helical
threads in the direction of the sludge-drain 17 and because
of the tightening space, the solid matter is compressed and
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drained through the sludge-drain 17. Due to its rotation,
the spiral brush 11 is self-cleaning. Due to the underwater
operation, the solid matter is discharged gently. The
abrasion of the spiral brush 11 is less than in flowing-
through operation.
According to Fig. 4, the aerobic biological clearing stage 44
includes a vertically standing, cylindrical, closed hollow
body 31, which is equipped with a sewage water supply 33 at
the bottom, a water discharge 37 at a cover 39 and a bypass
43 which connects an upper part 41 of the hollow body 31 with
a bottom region 35.
The hollow body 31 may be cylindrical with a circular diame-
ter which is considerably enlarged in its upper third or
quarter, wherein a transition to the upper part 41 is fun-
nel-shaped. The sewage water supply 33 discharges into a
pressurized discharge or volute chamber 49, having a surface
area which has a multiplicity of small outlets 51. The
cross-sectional area of the sewage water supply 33 is greater
than the sum of the cross-sectional areas of the outlets 51.
The bypass 43j which connects the upper part 41 of the hollow
body 31 with the bottom region 35, is equipped with a circu-
lating pump 57 which circulates the sewage water in the
direction of an arrow 63. A bypass inlet 53 is attached ~n
such a manner that it suctions off the sewage water at a
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~- 21~6230
point of transition to an enlarged diameter. Several injec-
tion connections 59 at the sewage water supply 33 and at the
bypass 43 are provided, through which pH-dosages, oxygen or
other special matter can be added in quantities that can be
adjusted and computer controlled through a number of sensors
65.
The hollow body 31 contains special solid matter serving as a
carrier or vegetation area for bacteria, e.g.
nitrobacteriaceae, which should float in the direction of an
10 arrow 67. The bacteria have the chance to develop unhindered
on the solid matter surface. The enlarged diameter of the
upper part 41 allows a reduced flow rate to take place, which
is symbolized by a shorter arrow 69. The lower flow rate
allows lowering or retaining of the solid matter with the
bacteria, which are not discharged through water discharge 37
but are recirculated to the bottom area 35 through the bypass
43. Solid matter, which is precipitated at the bottom of the
hollow body 31 or which is collected in the bottom area 35,
is whirled up by the sewage water which is discharged from
20 the bypass 43 and from the outlets 51 of the pressurized
discharge or volute chamber 49. Due to the difference in
ratio of the size of the outlets 51 and the effective area of
flow of the sewage water supply pipe 33, the sewage water
discharges in a pressurized manner through the outlets 51 and
is able to whirl up and lift those carriers of the solid
matter that are sedimented at the bottom. The sewage water
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21 96230
temperature is sensor-monitored and adjusted by means of
non-illustrated process-controlled immersion heaters.
Fig. 5 shows a vertically standing closed vessel 101 which is
cylindrical or cubical and has a cover 102 with a feeding
pipe 103 as well as a bottom 104 at which a water discharge
105 is attached besides a feeding pipe 106 that extends into
the upper third of the vessel 101 and carries a basically
cylindrical nozzle body 107. The fluid, which is to be
treated, is piped through the feeding pipe 106 into a nozzle
body 107. In an upper region 108 of the vessel 101, the
lighter medium, which may be a fluid or a gas, is supplied
during the operation of the device as a mixer. In a lower
region 109 of the vessel 101, the fluid, which has been
treated in the nozzle body 107, collects and is discharged
through the water discharge 105.
The difference in the level between the lighter medium in the
upper region 108 and the heavier medium in the lower region
109, is monitored by a level gauge 110 which regulates the
addition of the lighter medium by means of a non-illustrated
electronic control unit, in order to adjust the level between
a minimum val~e 111 and a maximum value 112.
As is seen in Fig. 6, the cylindric nozzle body 107 includes
a nozzle base 116 and a nozzle trunk 118 which are tightly
connected, as well as a multipart screwed-on nozzle tip or
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valve 120. Besides an arched or conoidal cover plate 122,
this complex nozzle body has an axial through bore 114, which
approximately corresponds to the outer diameter of the
feeding pipe 106 that is connected to the nozzle body 107 at
a bottom region of the nozzle base 116. Immediately above
the end of the feeding pipe 106, the axial through bore 114
is enlarged by a first ring groove 124 and forms a first
distributing chamber. The conoidal cover plate 122 is above
a short piece of pipe 123, which forms an annular water-flow
breakaway edge together with the upper edge of the nozzle
base at the ring groove 124. Beginning at the ring groove
124, a multiplicity of drilled holes 126 extend in axial
direction of the nozzle body 107 and end in a long
stretched-out second ring groove 127 in the nozzle trunk 118.
Following the second ring groove 127 is a multiplicity of
drilled holes 128 with a smaller diameter, which form further
breakaway edges. These drilled holes 128 lead into a fun-
nel-shaped impact chamber 129 in the nozzle tip or valve 120.
An upper edge of the axial through bore 114 of the nozzle
trunk 118 is shaped like a truncated envelope of a cone and
forms an underpart of a nozzle 130. The upper part 131 of
the nozzle together with a flange 132 thereof and a broad
rubber ring 133, is clamped between a nozzle-cheek 134 and a
screw cap 135 and forms the nozzle tip or valve 120, which is
screwed-on to the nozzle trunk 118 together with an inserted
rubber ring 136. A desired size of the nozzle gap 137 shown
in Fig. 7 is adjusted by tensioning the screw cap 135. The
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broad rubber ring 133 permits an elastic vertical movement of
the upper part 131 of the nozzle. This enables a self-clean-
ing of the nozzle gap 137. If a part of the nozzle gap 137
should get plugged up, the upper part 131 of the nozzle can
be lifted so as to enlarge the nozzle gap 137 so far that
despite the dirt accumulation, the required quantity of
medium can escape and the dirt accumulation can be scoured
through the enlarged nozzle gap. After the cleaning of the
nozzle gap 137, the former aperture size is restored by means
of the elastic force of the broad rubber ring 133.
As is also shown in the enlarged portion seen in Fig. 7, the
inclination of the surface at the nozzle gap 137 is chosen in
such a way that the width of the gap decreases in the direc-
tion of the top of the upper part 131 of the nozzle. In
addition, the edge of the upper part of the nozzle is
equipped with a breakaway chamfer 138. In this way, the
stream of the nozzle 130 is shaped like an envelope of a
cone, having a cone point which points at a point on the
center line of the nozzle body 107. In that part of the
axial through bore 114 of the nozzle trunk 118, which is
referred to as a nozzle-outlet chamber 140, a sleeve 141 is
added, having a lower end which is contracted and which ends
right above one or several nozzle ends 142. In the drawing,
only one nozzle end 142 is shown for the sake of clarity.
However, it is advantageous to provide several nozzle ends to
keep the fluid discharge unhindered. The conoidal cover
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.,
plate 122, which is fitted opposite the feeding pipe 106 at
the entry of the nozzle base 116, assures that no splash of
medium sprinkles back into the nozzle-outlet chamber 149 at
the lower end of the nozzle outlet chamber 143, due to its
conical shape together with the conically contracted sleeve
141.
When using the device as a mixer, the pressurized fluid is
supplied to the nozzle body 107 through the feeding pipe 106
and flows through the first ring groove 124 and several of
the drilled holes 126, into the second ring groove 127 and
the further drilled holes 128, and into the annular impact
chamber 129. The above-mentioned ring grooves and drilled
holes are formed behind each other in the jacket of the
nozzle body 107. At transition points between the ring
grooves and the drilled holes, water-flow breakaway edges are
provided, which break up the molecular structure of the
fluid. Due to the multiple passage along the water-flow
breakaway edges before discharging through the nozzle gap,
the fluid is very well prepared to absorb or yield other
medium molecules within the nozzle outlet chamber, by means
of a thorough loosening of the molecular structure.
The annular impact chamber 129 is followed by the annular
nozzle 130 having the nozzle gap 137 that becomes narrower in
the direction of the end of the gap. The upper part 131 of
the nozzle is shortened in contrast to the lower part of the
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nozzle and is equipped with the breakaway chamfer. The
nozzle generates a stream shaped like a truncated envelope of
a cone, which comes from different directions and meets in a
central point of impact in the nozzle-outlet chamber 140. In
this way, the velocity of impact virtually is doubled. In
this case the emitted stream generates a suction in the
direction of an arrow 144, through which a lighter medium
(liquid or gas), which is suctioned from the upper region 108
seen in Fig. 5 through the nozzle tip or valve 120 having an
open top, is blended or mixed with the medium discharging
from the impact chamber 129 and the annular nozzle 130, is
pushed in the direction of the nozzle end 142 and leads to
the lower region 109.
When using the device as a separator for liquids of different
density, it is operated by means of suctioning off the
heavier medium at the water discharge 105 and the lighter
medium at the feeding pipe 103 seen in Fig. 5. With the aid
of the suction generated in the nozzle body 107, the medium,
which has to be separated, is suctioned through the feeding
pipe 106. The annular nozzle 130 generates the stream shaped
like a truncated envelope of a cone in the nozzle-outlet
chamber 140. In this case the high velocity of impact and
the release of energy generate a cloud of the medium, having
a molecular structure which is broken up, and which allows
particles with a lower particle number density to be
suctioned off against the direction of the arrow 144. The
21 96230
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..... ..
particles with a higher particle number density follow the
suction coming from the nozzle end 142 and are transported
into the lower region. The removal of the lighter and the
heavier medium is monitored in the upper region 108 and in
the lower region 109 by the level gauge 110 and regulated in
such a way that the level between these media is kept between
the limiting values, which are given by the minimum value 111
and the maximum value 112.
Through the use of bypass recirculation of clarified water
through a clarified water recirculating line or return pipe
82 into the purification process, the bubble diameter and the
bubble quantity can be regulated and therefore the flotation
in the mixing basin 30 of the pre-flotation apparatus, the
aerobic biological clearing stage 44 and the mixing basin 60
of the reflotation apparatus, can be controlled. The process
described above is illustrated in the flow chart of Fig. 2
which includes the line 82.
The aquatritor shown in Figs. 8 and 9 performs three func-
tions, namely physical pressure relief flotation, mechanical
deposition of solids by means of sedimentation, and chemical
precipitation:or flocculation. The aquatritor can be em-
ployed for pre-flotation downstream of a sand trap, as a
pH-stabilization section downstream of the biological purifi-
cation, and the flocculation section can be used in case of
special requirements made on the degree of purity of the
w -23- 2 1 9 623 0
waste water. The aquatritor combines the operation of, and
therefore replaces, the floatation device and the sedimenta-
tion basin described above with respect to ~igs. 1-6.
The physical pressure relief flotation section is used for
the removal of filterable materials as well as for ionizing
the waste water. The flotation in the aquatritor is based on
the controllable atomization of gases in liquids. The
aqua-injector, which is a gas injection system developed by
firm AquaPlan, assures an even gas bubble section and even an
rising speed, along with an arbitrarily selectable bubble
diameter.
Floating materials adhere to the slowly rising microbubbles
and are transported by them to the surface of the aquatritor
in an area 203 downstream of an inlet 201. The forming foam
is carefully moved from there by means of a motor-driven
clearing system 202 into a runoff trough in order to be
further processed in a sludge processor.
With regard to the mechanical sedimentation, based on the
flow conditions generated by the structure of the aquatritor,
the kinetic energy of the floating materials outside the
flotation zone 203 is affected in such a way that they are
deposited on the bottom of the aquatritor in an area 204.
The sediment is periodically removed through a valve 205 and
passed to the sludge processor.
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Regarding chemical flocculation, in the case of special
requirements or with extremely dirty waste water, the
aquatritor can also be used as a reaction and flocculation
basin. The aqua-injector is used as the system for injecting
and mixing chemicals. Flocculation takes place in areas 203
and 204 of the aquatritor during a holding time. Depending
on their weight and size, flakes are continuously removed
from the waste water by flotation or sedimentation.
The more detailed illustration of the aquatritor in Fig. 10
includes a waste water inlet 211. An inlet 212 of an injec-
tor bypass provides water enriched with micro-bubbles,
analogously to an aquaseptor (flotation). An inlet connector
213 leading to an interior cylinder generates a tangentially
circulating fLow. An outlet connector 214 is provided for
material which can be sedimented. Reference numeral 215
represents a flotation zone, whereas reference numeral 216
represents an outer ring clear water zone. A height-adjust-
able slide 217 is used for adjusting a water level. A clear
water outlet box 218 is also provided. A blade 219 of a
circular removal device removes floating matter from the
surface of the liquid into a floating matter run-off trough
224. The blade 219 of the circular removal device has a
strap 220. The circular removal device also has a frame 221,
a motor 222 and a drive shaft 223. The run-off trough 224
leads to an outlet connector 225 for the floating matter.
Finally, a holder 226 is provided for the interior cylinder.
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Fig. 11 shows that the bioreactor includes a waste water
inlet 231 and an inlet 232 for the injector bypass leading to
a pressure outflow pot 233 having outlet openings 234. The
bioreactor has an inner pipe 235 and a water run-off 236
disposed at the top. The bioreactor replaces the biological
clearing stages or reactors 44 and 45 which are described
above with regard to Figs. 1-6.
The four chamber system shown in the respective top and side
views of Figs. 12 and 13 and the flow chart shown in Fig. 14
with the bioreactors illustrated as circles outside the
chambers, functions as a buffer and builds a connection
between the bioreactors. The four chamber system replaces
the mixing basin with a single chamber which was discussed
with reference to Figs. 1-6.
The description of the operation of the four chamber system
follows the arrows shown in the flow chart of Fig. 14. Water
streams tangential into a first chamber from a preclearing
stage. A circulating flow direction then takes place.
Reactor pumps draw off water from the downstream side of the
chamber and supply the reactor with a continuous flow.
,
Due to the use of a small reactor outlet pipe in comparison
with an overflow edge between the chambers, the speed of the
flow from the reactor outlet is much stronger than the flow
between the chambers. This induces a vertical flow from the
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2 1 96230
surface to the bottom of the chamber from where the waste
water will be drawn off again.
In the case of the flow between the chambers, it is important
to know that the illustrated baffles become higher as seen
from one chamber to the other. It is enough to only increase
the baffle height by 1/2 to 1 cm. The water level tries to
reach the same height, conditioned on the open channel
system. This prevents movement of amounts of waste water
from one chamber into the other without going through the
bioreactor.
Manually operated submersible sludge pumps are installed on
the bottom of each chamber in the case of sand leaving the
reactors and entering into the chambers.
The reaction that takes place in the four chamber system is
only an attenuated reaction of the bioreactors because the
concentration of microorganisms and oxygen is low.
