Note: Descriptions are shown in the official language in which they were submitted.
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BIOLOGICAL WASTEWATER PURIFICATION DEVICE
1 BACKGROUND OF THE INVENTION
Technical Field
The invention concerns a biological wastewater purification device with a
multi-chamber tank with separating walls to divide the tank into at least one
pre-treatment chamber containing activated sludge and at least one
purification chamber, as well as pump installations for transporting and
treating wastewater.
~'pescription of the Problem
As a general rule, small wastewater treatment systems contain a plurality of
pumps such as a clear water removal pump, a sludge pump, a ventilator, etc.
Additional pumps may also be provided to transport and treat, e.g. aerate,
the wastewater during the purification process.
A large number of pumps not only leads to substantial costs for the pumps
themselves, but also to additional expenditure for cabling and controlling the
pumps. This makes the systems more expensive, more complicated and more
susceptible to wear and tear.
SUMMARY OF THE INVENTION
This invention is therefore based on the task of creating a wastewater
purification device of the above-mentioned type, which requires less
equipment-related expenditure.
In order to solve this task, the wastewater purification device according to
the invention is characterised in that a distributor for dividing the pump
output into at least one main flow and at least one secondary flow is
connected downstream of at least one pump installation.
This implies the use of a pump capable of performing two functions. One
pump and related accessories can be dispensed with. The distributor is
preferably configured to permit relatively accurate dosing, especially of the
secondary flow. Under these circumstances, the invention can be used in
such a way that, for example, the operation to return the sludge to the pre-
treatment chamber, which need only take place from time to time and with
relatively small quantities of water and sludge, is performed by the
secondary flow.
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1 Sludge return is an operation used in activated sludge wastewater
purification processes to supply the fresh wastewater flowing into the
sedimentation chamber or pre-treatment chamber with sludge in which
micro-organisms have already formed.
The dosing of the secondary flow can be achieved in different ways. Valves
may be provided, which, for example, let through a certain limited volume of
water at the start or end of the pumping operation.
By way of the main task, the pump according to this invention can, for
example, pump the water in the purification chamber through a Venturi
aerator. Other pump tasks are also feasible.
A suitable valve providing a simple means of allowing a dosed, relatively
small volume of water to flow into the secondary line, comprises, for
example, a valve ball positioned so that it can move between two valve seats
in a rising section of the secondary line. When the pump is switched on, the
valve ball is lifted off the bottom seat and carried upwards with the flow of
water towards the top valve seat. During this time, water can flow past the
valve ball into the secondary line until the ball comes into contact with the
top valve seat, where it is held fast by the pressure of the rising water. If
the
pump is turned off, the ball will sink back down onto the bottom valve seat.
Hence this is a solution allowing a limited, dosed quantity of water to flow
into the secondary line at the start of the pumping operation.
A valve of this type can be supplemented by an upstream or downstream
non-return valve.
Another embodiment of a suitable valve might comprise a valve ball which
can move to and fro between two valve seats located at an outlet line of the
pump on the one hand and the secondary line on the other hand, and which
has a water reservoir in a rising section of the main line. If the pump is
switched on, the ball is lifted upwards towards the valve seat on the
secondary line, and the secondary line is closed off.
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The water flows into the main line and then into the water reservoir. If the
pump is switched off, the ball falls back onto the valve seat on the outlet
line
of the pump. The water collected in the water reservoir flows back into the
secondary line, which is now open.
Certain exemplary embodiments may comprise a biological purification device
comprising: a multi-chamber tank with separating walls to divide the tank into
at
least one pre-treatment chamber containing activated sludge and at least one
purification chamber; at least one pump installation for transporting and
treating
wastewater, the pump installation being arranged inside the purification
chamber;
and a distributor for dividing a pump output into at least one main flow and
at
least one secondary flow, the distributor connected downstream of the at least
one pump installation and comprising a main line and a secondary line which
proceed from a pump outlet line, the secondary line leading to the at least
one
pre-treattnent chamber and comprising a ball valve arrangement being provided
in
a rising section of the secondary line and comprising a valve ball which can
be
moved up and down between two valve seats facing each other at a
predetermined distance.
These valve types merely serve as examples of numerous other possibilities.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred examples of embodiments of the invention will be described in more
detail below with reference to the enclosed drawings, in which
Fig. la and lb show a first embodiment of a valve envisaged for the
secondary line in accordance with the invention, in
different operating positions;
Fig. 2a to 2c show an equivalent view of a second embodiment of a
valve;
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Fig. 3a to 3e show a third embodiment of a valve according to the
invention;
Fig. 4a and 4b show a fourth embodiment of a valve.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Fig. la is a diagrammatic representation of a purification chamber 10
containing more or less purified water up to water level 12. Inside
purification chamber 10 there is a pump 14 from which proceeds a pump
outlet line 16 which immediately branches into a main line 18 and a
secondary line 20. In the example shown, the main line feeds into a Venturi
aerator 22, and an air line 24 intersects with the narrow portion of said
Venturi aerator.
In a rising section of secondary line 20 there are two valve seats 26,28
facing
each other at a distance, between which a ball 30 can be moved up and
down.
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l When pump 14 is switched on, valve ball 30 is gradually lifted off the
bottom
valve seat 26 until it comes into contact with top valve seat 28. As the ball
rises, water flows past the ball and through secondary line 20. This water
flow stops as soon as the ball comes into contact with the upper valve seat
28. It is held in this position by the pressure of the water for as long as
pump 14 stays in operation. When pump 14 is switched off, valve ball 30
sinks back down onto the bottom valve seat 26.
This process is repeated the next time the pump is switched on. This
provides a means of occasionally pumping limited volumes of sludge-
containing water back into the pre-treatment chamber (not shown) via
secondary line 20 without the need for a separate pump.
Fig. 2a to 2c show another embodiment of the invention. This embodiment is
based on the embodiment of Fig. la and lb, but also includes a non-return
valve in addition. The same reference numerals have been assigned to
components already mentioned in the context of Fig. 1. Fig. 2a to 2c also
provide for the same valve ball 30 as shown in Fig. 1, which can be displaced
between bottom valve seat 26 and top valve seat 28 in the manner already
described.
Downstream of the arrangement comprising valve ball 30 with the two valve
seats 26,28 there is a non-return valve 32. In the case illustrated, the non-
return valve is contrived as a ball valve. It comprises a valve ball 34,
which,
in the upstream direction, can rest against a valve seat 36, thereby
preventing a return flow. Valve ball 34 is located inside a slightly broadened
chamber 38, in which a ball support 40 is disposed, against which the ball
rests when the non-return valve is opened (Fig. 2c).
3() The way in which this valve functions will be described below.
Fig. 2a shows the position in which pump 14 is switched off. When pump 14
is switched on (Fig. 2b), valve ball 30 is gradually lifted upwards. As
already
mentioned, there is only a small gap between valve ball 30 and the walls of
the secondary line, so water can rise up past valve ball 30.
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l. This flow of water lifts valve ball 34 of non-return valve 32 up off its
valve
seat 36 and presses the ball against support 40. When valve ball 30 comes
into contact with the top valve seat 28 (Fig. 2c), the flow of rising water is
interrupted. Valve ball 34 of the non-return valve 32 sinks back down onto
its valve seat 36.
Fig. 3a to 3e are equivalent to Fig. 2a to 2c, except that in Fig. 3a to 3e,
the
non-return valve is disposed before or upstream of valve ball 30 with the two
valve seats 26,28. As the figures coincide fully in all other respects, the
same
reference numerals will be used as in Fig 2a to 2c and, to some extent, in
Fig. la and lb.
The way in which the embodiment of Fig. 3a to 3e functions will now be
described below.
Fig. 3a shows the position in which the pump is switched off. If pump 14 is
switched on, valve ball 34 of non-return valve 32 is first lifted off its
valve
seat 36 (Fig. 3b). The flow of water can now enter secondary line 20 so that
valve ball 30 is lifted up from its bottom valve seat 26 to its top valve seat
28. Water flows through secondary line 20 during this time. As soon as valve
ball 30 reaches the top valve seat 28 (Fig. 3c), the flow of water in
secondary
line 20 is interrupted. Valve ball 34 of non-return valve 32 therefore sinks
back down onto its valve seat 36 (Fig. 3d). When the pump is switched off,
valve ball 30 also sinks back down onto its bottom valve seat 26 (Fig. 3e).
Fig. 4a and 4b show an arrangement which functions according to a different
principle than the embodiments described thus far. In a purification
chamber 42 there is a pump 44 from which a pump outlet line 46 proceeds
in a vertical direction.
Adjoining a bottom, non-designated first section of pump outlet line 26, the
latter runs into a broadened section 48, and at the transition between the
bottom section and the top, broadened section 48 there is a valve seat 50, on
which a valve ball 52 is seen resting in Fig. 4a. Disposed concentrically
inside this broadened section 48 is inlet 54 of the secondary line 56, which
is equivalent in terms of the way it functions to the secondary line 20 of
Fig.
1.
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1 There is a valve seat 58 at this inlet 54 of secondary line 56. This valve
seat
58 lies directly opposite bottom valve seat 50 and is disposed coaxially to
the
latter.
The main line 60, which corresponds to the main line 18 of the previously
described embodiments, branches off from the broadened section 48 of pump
outlet line 46 of the embodiment according to Fig. 4a and 4b. Main line 60
has a water reservoir 62 in a rising section adjoining the broadened section
48 of pump outlet line 46.
The way in which the embodiment of Fig. 4a and 4b functions will now be
described below.
Fig. 4a shows the position in which pump 44 is switched off. Valve ball 52
rests against its valve seat 50. When pump 44 is switched on, valve ball 52 is
lifted upwards from bottom valve seat 50 towards valve seat 58 at the inlet of
secondary line 56. This seals off secondary line 56. The water flows through
the main line 60. If pump 44 is now switched off, valve ball 52 sinks back
down to its bottom valve seat 50. Hence this arrangement operates as a non-
2() return valve. The water collected in the water reservoir 62 cannot run off
via
the main line because of the heights involved and therefore flows back into
the broadened section 48 of the pump outlet line and from here through
secondary line 56. At this point it should be pointed out that Fig. 4a and 4b
in particular are merely diagrammatic illustrations. It is obvious that the
volume of water reservoir 62 and of the broadened section 48, and the
arrangement and dimensions of secondary line 56 must be chosen so that a
given volume of water can flow away via secondary line 56.
3()
