Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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~ethod and arrangement for treatment of sludge water
The present invention relates to a method and an arrangement
for treatment of the sludge water contents in waste water
purification arrangements of moderate size, such as waste
water wells, b,y means of a mobile ~lant.
Small purification arrangements for ~urification of waste water '
from one or a few residential houses include sludge separators
such as two or three waste water wells connected in series.
To secure proper operation it is necessary frequently to remove
the sludge accumulated in the waste water wells. Thereby, the
whole sludge water contents of the well is removed and trans~orted
to a central purification plant for treatment. Thus, compara-
tively long trans~orts are necessary. Further, the central
~urification plants must be capahle of treating considerable
amounts of sludge water.
The aim of the present invention is to provide an improved
method and arrangement for treatment of the sludge water, where
less trans~ortation is reauired, and where there is a little
need of central purification plants. This is obtained h,~ the
method and arrangement defined in the claims.
The invention is further described below with reference to the
drawings, in which
Fig 1 and 2 are side views of an emhodiment of the invention;
Fig 3 is a detail view alon~ the dotted lines A - - A in
Fig. l;
Fig 4 is a simplified schematic diagram of the emhodiment
of Fig. l; and
Fig 5 is a schematic illustration of o~eration stens
included in a full operation cycle.
The mobile sludge water treatment plant disclosed in Fig 1
is arranged on truck chassis. It includes a collecting tank 1
having room for 5 m3 of sludge water, whereby it is possible
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to treat the total contents of most waste water wells as
a single batch. The collecting tank 1 is arranged together
with a purified water tank 15 in a common container, which
is divided into two cavities by an internal senarating wall
having the shape of several cones, the u~Per cavity forming
said collecting tank 1 and the lower cavit~ formin~ said
purified water tank 15. The volume of the lower cavity is
almost the same as that of the upper cavity. The conical
shape of the separating wall facilitates sedimentation of
the treated sludge water and discharge of the contents of the
collecting tank 1. Through a valve 22 (Fi~ 3) the collecting
tank 1 is connectable to a ~ipe 2, which is connected to a
hose 10 arranged on a hose reel (11). The purified water
tank 15 is connectable to the pioe 2 th~ough a valve 23
(Fig 3). The pipe 2 and the hose 10 are used both for sludge
water inlet and for purified water outlet. Through a portioning
means 3 a chemicals container 4 is connected to the ~ipe 2.
An arrangement 5 for providing turhulent flow is provided
in the pipe 2 between the portioning means 3 and the collecting
tank 1.
The lower part of t~e collecting tank 1 is connected to a
pipe 9, which is coupled to a sediment tank 6 through a
valve 8. The lower end of the sediment tank 6 is connected
through a valve 12 and a pipe 13 to a de-watering means 7,
com~rising a drum-type vacuumfilter arranged in a vessel 14
(Fig 4). The sludge level in the vessel is controlled by a
l~vel sensor 39 (Fig 4) activating the valve 12 to o~en or
to close. Below the de-watering means 7 a sludge container 18
is arranged in such a position that de-watered sludge from
the vacuumfilter falls down into the sludge container 18. A
hydraulic cylinder 20 operates a discharge door 19 arranged
at the lower end of the container 18. The inner part of the
drum-type vacuumfilter is connected to the purified water
tank 15 through a valve 17 and a pi~e 16.
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The ~ower is delivered b~ a niesel engine 21 which drives
a h~draulic oump and an electric;ty generator.
Trans~ortation of water and sludge within the plant is
accomplished by applying different pressure in the various
tan~s and containers. The oressure and vacuum systems
are shown in Fig 4, which is a simolified diagra~ where
the sediment tank 6 has been omitted.
A vacuum pump 24 is connected through a moisture separator 25
to a pipe 28, which is connectable to the collecting tank 1
and the purified water tank 15 by means of valves 30 and 31,
respectively. A com~ressor 25 is connected through a Pressure
air tank 27 to a pipe 29, which is connectable to the collecting
tank 1, the purified water tank 15 and the de-watering means 7
by means of valves 32, 33 and 34, respectively. In series with
the valves 32 and 33 regulating valves 35 and 36, respectively,
are connected. When a sediment tank is orovided, it is connected
in a similar matter as the tanks 1 and 15. Level sensors 37,
38 and 39 are provided in the collectin~ tank 1 and the de-
-watering ~eans vessel 14, res~ectively. The de-waterin~ means 7
and the hose reel are driven by h~draulic motors 40 and 41,
respectively. A protection valve 41' is connected between the
pioe 2 and the portioning means 3 to orevent water in the
pipe 2 from entering into the nortioning means 3.
The operation o~ the ~lant is described below with reference
to Fig 4.
The hose 10 is unwound from the reel 11 and brough~down into
the waste water well to be breated. The vacuum pum~ 24 is
connected to the collecting tank 1, and the slud~e water is
sucked through the hose 10 and the oioe 2 into the tank 1,
while the oortioning means 3 delivers chemicals from the
chemic-al container 4 into the sludge water. ~hen passing the
turhulent flow arrangement 5 the chemicals and the sludge water
are thoroughly mixed. When all the sludge water in the waste
water well has been moved into the collecting tank 1, the
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valve 22 is closed and the floccing process begins in
that tank. During that process, the contents in the
~urlfied water tank 15, which emanates from the treatment
o~ the previous waste water well, is exhausted into the
empty waste water well now being treated. This is accomp-
lished by the opening~of the valves 23 and 33, whereby the
water is pressed through the pipe 2 and the hose ln, the
end of which still being situated in the waste water well.
Then, the valve 22 is closed, the valve 12 is opened and
the pressure in the collecting tank 1 is increased by
opening the valve 32, whereby flocced sludge water is
flowing throu~h the pipe 13 into the vessel 14 of the
de-watering means 7. The de-watering ~rocess beings as
the valve 17 is opened, and the pressure in the purified
water tank 15 is decreased by o~ening the valve 31, wherebv
purified water is transported through the pipe 16 into the
tank 15 while de-watered sludge falls down into the sludge
container 18. Sludge sticking onto the vacuumfilter is
released by applying pressure air blows from the Pressure
air system.
When the de-~atering starts, the hose 10 is reeled onto the
hose reel 11 and the ~lant is moved to the next waste water
well in turn to be treated. The de-watering continues during
transportation until all the sludge has been de-watered.
When required a separate sedimentation steo of the flocced
sludge water in the collecting tank 1 is included in the
process. Then, the sediment tank 6 is used in a manner shown
in Fig 5, which illustrates five consecutive treatment ste~s
together forming a~ull plant operation cycle.
Step 1 includes removin~ the waste water well contents into
the collecting tank 1 while adding chemicals as has previously
been described. Then, the valve 22 is closed and step 2 begins.
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In step 2 the slud~e water in t,he tank 1 is flocculating
and sedimenting to the bottom of the tank. Simultaneousl~,
~urified water is removed from the tank 15 into the well
as has oreviously been described. When the sedimentation
process is slowing down in the tank 1 (after apDrox. 1~
minutes when calcium-hydroxide or iron chloride is used),
step 3 begins.
In step 3 the tank 1 is connected to the pressure air tank 27
and the valve 8 is opened. As soon as sediment is transported
from the tank 1 into the sediment tank 6 through the pi~e 9,
the valve 12 on the pipe 13 is oDened, whereby the vessel 14
ln the de-watering means 7 is connected to the sediment
tank 6 and sediment is transported into the vessel 14.
Thereby, the de-waterin~ means 7 begins to o~erate, the
valve 17 is opened and the air pressure in the purified
water tank 15 is reduced by connecting the tank 15 to the
vacuum source 24. When all sediment in the tank 1 has been
transported into the sediment tank 6, the valve 8 is closed.
The tank 1 now contains water which has been clarified
during the sedimentation process. Com~ared with the sludge
water this clarified water contains only a small fraction
of impurities.
In step 4, the clarified water contents of the tank 1 is
removed into the waste water well as the valve 22 is opened.
Simultaneously, de-watering of the sludge sediment continues.
In step 5, the hose 1~ is reeled onto the hose reel 11 ana
the mobile plant is transported to the next waste water well
to be~treated. Durin~ trans~ortation, the de-watering of the
sludge sediment continues until all sediment has been treated.
When arriving at the next waste water well to be treated, a
full nlant operation c~cle has been com~leted and the plant is
ready to repeat the process.
The sludge collected in the sludge container 18 is removed
through the discharge door 19 when several waste water wells
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have been treated. Such de-watered ~lud~e is transoorted
to suitable receiving olants.
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