WO2008046431A1

WO2008046431A1 - Biological sewage treatment device

Info

Publication number: WO2008046431A1
Application number: PCT/EP2006/009975
Authority: WO
Inventors: Thorsten Vogt
Original assignee: Atb Umwelttechnologien Gmbh
Priority date: 2006-10-16
Filing date: 2006-10-16
Publication date: 2008-04-24
Also published as: DE112006004075A5

Abstract

Biological sewage treatment device (10) having at least one clarification chamber (14) and an immersion pump (28) arranged in the clarification chamber (14) for treating waste water, characterized in that the pressure side of the immersion pump (28) is connected to the inlet of a multiwave value (34, 90) having two outlets, of which a first outlet (36) is connected to a mixing line (38) opening into the clarification chamber (14), and a second outlet (42) is connected to an emptying line (44) which opens into a clarified water outlet (26).

Description

BIOLOGICAL CLAWING DEVICE

The present invention relates to a biological clarifier with at least one clarification chamber and a submerged pump arranged in the clarification chamber for the treatment of wastewater.

For wastewater treatment for households that are not connected to the public sewer system, small sewage treatment plants are often used. Apart from the actual clarification chamber, they usually also comprise at least one pre-clarification chamber upstream, which serves to separate coarse matter and store it. From the primary clarification chamber, the wastewater is introduced into the actual clarification chamber for biological clarification using the SBR method (Sequencing Batch Reactor), which is known as such. In this case, the contents of the clarification chamber must be aerated and mixed from time to time. The purified wastewater is removed by suitable pumping equipment in a clear water outlet. Furthermore, it may prove necessary to remove excess sewage sludge from the clarifier.

In the prior art, the above-mentioned functions are performed by different devices such as a plurality of pumps or only one pump and a plurality of control valves. EP 1 388 524 A1 shows a plant in which only a single submersible pump is arranged in the clarification chamber, which takes over the aeration, the sludge recirculation and clear water discharge. In this arrangement, however, it is necessary to arrange in the respective branch lines, which emanate from the submersible pump, solenoid valves, which are shut off or opened according to the respective pump function. Such valves are prone to failure and cause a certain maintenance and monitoring effort to ensure proper operation of the system. In addition, EP 1 650 169 A1 shows a clarifier in which the submersible pump is connected on the pressure side to a sludge return line, from which a branch line branches off to the clear water outlet. By a simple valve device, the sludge recirculation line is closed after the discharge of a surge of water or sewage sludge. If the pump is operated for a long time, clear water can subsequently be discharged into the outlet. The mixing and ventilation function must, however, be taken over by an additional submersible fan. The object of the present invention is therefore to provide a biological clarifier of the type mentioned, which manages with a reduced number of components and in which in particular the number of parts requiring maintenance and failure-prone parts is reduced, so that the entire system cost and low Effort can be operated trouble-free.

This object is achieved by a biological clarifier with the features of claim 1.

The clarifier according to the invention comprises only a single submersible pump in the clarifier, which is connected to the inlet of a directional control valve with two outlets. The first outlet is connected to a mixing line which opens again into the clarification chamber and can be used to mix the contents of the clarification chamber by the submersible pump pumping the wastewater contained therein through the mixing line. A second outlet of the directional valve is connected to a drain line, which opens into a clear water outlet.

The proposed system also comes only with a single submersible pump, but beyond requires only a single valve, namely the directional control valve, which is switchable between the first and second outlets according to the desired function. In mixed operation, that is to say in the case of the above-described pumping of the clarification chamber contents through the mixing line, the first outlet is open, while the second outlet is closed. Conversely, the first outlet is closed when discharging the clear water. Since this switching and Abstellfunktion is taken over by a single valve, which can be optionally controlled by the pressure conditions at his EinlaJ3, further control devices may be unnecessary, as they must be required in the prior art to different solenoid valves in different line sections coordinate. As a result, a trouble-free and maintenance-free operation is possible. The arrangement of the submersible pump with the connected directional control valve is thus limited to the essential functions of mixing and aeration of the clarifier content and clear water -Ab promotion, while other functions such as in particular the supply of wastewater from the primary chamber into the clarifier by very simple design Facilities such as an overflow can be adopted.

Preferably, a connecting line opens into the mixing line, the free end of which opens into the primary clarification chamber. This connecting line is preferably used for sucking wastewater and / or air from the primary clarification chamber. The necessary suction pressure is also built up by the submersible pump. The flow cross sections in the mixing line and in the connecting line are to be dimensioned so that at a sufficient flow pressure in the mixing line according to the Venturi principle sewage, air or an air-waste water mixture is sucked through the connecting line and conveyed into the mixing line.

In a further preferred embodiment, the free end of the connecting line comprises a bell-shaped float whose lower edge is located below the waste water level of the primary chamber and which has at least one opening at a height above its lower edge. With the help of such a floating body can control whether air or sewage is sucked from the primary chamber. If the float is filled to a level above its opening, only waste water is sucked. If the opening is above the water level, air is sucked in. Preferably, the up and down movement of the float is limited by an upper and a lower stop in the primary clarification chamber. If the level in the pre-settling chamber is in a range between the upper and lower stop, the floating body floats on the surface, the opening being below the water level due to its own weight in the state filled with water (suction of waste water). If the float reaches the lower stop when the level drops further, it can not move further down, so that the level drops below the level of the opening and air is sucked in. As a result, the weight of the float is reduced so far that the opening is raised above the wastewater surface and only air is conveyed. The connecting line empties, and the pe- gel in the primary clarification chamber only rises when further wastewater is filled into the primary clarification chamber from the outside or from an upstream second primary clarification chamber. The float then finally reaches the upper stop until the level rises above the opening and, during the mixing operation of the pump, fills the floating body, so that the discharge from the primary clarification chamber into the clarification chamber can begin again.

Preferably, the connecting line is also provided for returning sludge from the clarification chamber into the primary clarification chamber. This can be done with switched-off submersible pump by the sludge is sucked on the principle of a communicating tube through the mouth of the mixing line in the connecting line and flows back into the primary chamber in a free slope. For this purpose, the level in the clarification chamber must be higher than in the pre-clearing chamber, which however is due to the process by the suction during filling of the clarification chamber the case.

In a further preferred embodiment, a sludge return line, which opens into the pretreatment chamber, starts from the discharge line. As will be described in more detail below, this can be done a surge recycling of sewage sludge with open drain line, whereupon the discharge of clear water takes place in the clear water outlet.

Further preferred embodiments of the biological clarifier according to the invention relate to embodiments of the directional control valve in a particularly simple and reliable construction, which does not require external control organs.

In the following a preferred embodiment of the present invention will be explained with reference to the accompanying drawings.

Fig. 1 shows an embodiment of the biological clarifier according to the invention in a schematic cross section; FIGS. 2 to 4 are illustrations of the process sequence during the aspiration from the primary clarification chamber into the clarification chamber of the clarifier from FIG. 1;

Figures 5 and 6 are side sections through various embodiments of a directional control valve of the biological clarifier according to the invention; and

Fig. 7 is a detail view of the clarifier according to the invention comprising a pressure equalizing line on the discharge line.

The biological clarifier shown in FIG. 1, which is designated in its entirety by the reference numeral 10, comprises a pretreatment chamber 12 arranged on the right in the FIGURE and a clarification chamber 14 which are arranged within a common cylindrical container 16 which extends through a cover 18 is closed with an access 20. Within the container 16, the pre-treatment chamber 12 and the clarification chamber 14 are separated from each other by a partition 22. In the upper region of the outer wall of the container 16 of the pretreatment chamber 12, a waste water inlet 24 is arranged, through which wastewater is introduced into the pre-treatment chamber 12. Within the primary clarification chamber 12, coarse impurities may settle on the bottom or in the area of the water level before the wastewater is transferred to the actual clarification chamber 14 in a manner which will be described below, in which a biological wastewater purification using the SBR process (Sequential Batch reactor) is performed. The process as such is well known and should therefore not be described further here. After cleaning, the clear water is removed as a process product through a clear water outlet 26 from the container 16.

Within the clarification chamber 14, a submersible pump 28 is arranged, which is immersed at least with its suction side 30 in the wastewater. To the pressure side 32 of the submersible pump 28, which is formed by a lateral outlet on the pump housing, a directional control valve is connected, which is shown schematically in the figure and generally designated 34. While the inlet of the directional valve 34 to the pressure side 32 of the submersible pump 28 is closed, a first outlet 36 of the directional control valve 34 is connected to a so-called mixing line 38, the free mouth 40 is below the water level. The remaining second outlet 42 of the directional valve 34 is connected to a drain line 44, which opens into the clear water outlet 26.

The directional control valve 34 is switchable between two positions, between a first position in which the first outlet 36 is opened and the second outlet 42 is closed and thus the mixing line 38 is free, and a second position in which the first outlet 36 is closed and in which can be pumped through the open second outlet 42 in the drain line 44. Switching between the two positions takes place according to a cycle of the clarification method which will be described in more detail below.

Downstream of the first outlet 36 of the directional control valve 34 opens a connecting line 48 in the mixing line 38. The free end 50 of the connecting line opens into the pre-treatment chamber 12 and includes a bell-shaped float 52 with openings that can be located above or below the wastewater level in the primary chamber 12 so that through the connection line 48, water, air or a water-air mixture can be sucked into the mixing line 38 via the dividing wall 22. The term "bell-shaped" is intended to describe in the present context only a hollow, open at the bottom mold and include, for example, a cylindrical shape or the like. Structure and function of the float 52 will be described below in more detail. The flow cross sections of the mixing line 38 and the connecting line 48 at the junction 54 of the connecting line 48 in the mixing line 38 are dimensioned so that when the second outlet 42 and opened first outlet 36 and the submersible pump 28 is switched on, the waste water flow through the mixing line 38, the tube content of the connecting line 48th sucks and the resulting mixture from the mouth 40 of the connecting line 38 exits. The connecting line 48 may be a flexible hose. The individual functional cycles of the biological clarifier 10 according to the invention described below can be controlled exclusively by the operation of the submersible pump 28 and the directional control valve 34. Other valves are not required. The float 52, however, is designed so that, depending on the level in the pre-treatment chamber 12 optionally water or air is transferred to the clarification chamber 14.

In the following, a charging and aeration phase of the clarifier 10 will be described with reference to FIGS. 2 to 4. In these figures, the emptying line 44 closed during these phases is not shown for the sake of clarity. The first outlet 36, to which the mixing line 38 is connected, is open.

Referring to FIGS. 2 to 4, an upper stop 56 and a lower stop 58 are attached to the partition wall 22, which limit the up and down movement of the floating body 52. In Fig. 2, the level of wastewater within the primary chamber 12 is significantly higher than in the clarification chamber 14 and is above the upper stop 56. Due to the buoyancy of the float 52 this remains hanging on the upper stop 56 and can not move further up. During operation of the submersible pump 28 thus wastewater from the primary chamber 12 is sucked through the connecting line 48 into the mixing line 38 and conveyed into the clarification chamber 14. At approximately half its height, the floating body 52 has a number of openings 62. If the floating body 52 is completely filled with water, the openings 62 are all below the water level, so that further water is drawn in through the connecting line 48. So this is also the case when the level in the pre-treatment chamber 12 drops below the level of the upper stop 56 and the filled float 52 between the stops 56,58 can swim freely (this situation is not shown in the figures). If the level continues to fall to the level shown in Fig. 3, the float 52 is at its lower edge on the lower stop 58, so that at a further decreasing level, the openings 62 are free and briefly an air-water mixture is sucked. Due to the intake air, the water flow is interrupted, and the connecting line 48 empties. The weight of the float 52 decreases due to the ingress of air, and it jerkily emerges so far that the openings 62 are above the water level (Figure 4). Then at the confluence According to the venturi principle, only air is sucked into the mixing line 38, and the wastewater level in the primary clarification chamber 12 can not fall further.

The floating body 52 thus controls due to its buoyancy and the arrangement of the openings 62 in connection with the stops 56,58 the charging cycle in which wastewater from the primary chamber 12 is conveyed into the clarification chamber 14. The minimum water level in the pre-treatment chamber 12 is determined by the position of the lower stop 58. If the water level in the primary clarification chamber 12 at the beginning of a feed cycle is higher than in the clarification chamber 14, as shown in FIG. 2, this has the advantage that even after switching off the submersible pump 28 according to the principle of the communicating tubes automatically and without energy Water from the pre-treatment chamber 12 is sucked in until the flow is interrupted by the ingress of air or the water levels have become equal. Advantageously, the first charge is thus carried out after a settling and pumping down phase, since at this time the water level in the primary clarification chamber 12 is generally higher than in the clarification chamber 14 and thus after a brief intake and mixing phase the submerged pump 28 is stopped can, so that wastewater from the primary chamber 12 can be performed without energy consumption in the clarification chamber 14.

During the suction of wastewater from the primary clarification chamber 12, a thorough mixing of the contents of the clarification chamber 14 without aeration, that is to say without oxygen supply, is carried out. It is merely mixed by the submersible pump 28, the contents of the clarification chamber 14 under entry of new wastewater via the connecting line 48, so that prevail in the sewage chamber 14 anoxic conditions. This is necessary for complete nitrogen removal (denitrification). Furthermore, the carbon needed for the microorganisms is introduced into the clarification chamber 14 by the fresh wastewater. The ventilation is carried out by the suction of air only then and not, as is known in the prior art, with simultaneous mixing, for example by a dip fan, which carries out the mixing simultaneously with an air entry. This inventive advantage is realized by the proposed clarifier 10 with little effort. Advantageously, the feed cycle is relatively short compared to the period of time provided for subsequent aeration. At the beginning of each ventilation phase, it is possible to fill the clarification chamber 14 with a correspondingly high water level in the primary clarification chamber 12 by the inflow of waste water into the system and at a level above the opening of the float 52. At an advanced time of the cycle, in which the water level is higher than in the pre-treatment chamber 12, the submersible pump 28 can be turned off for a time adapted to the utilization of the clarifier 10 so that excess sludge is returned to the pre-treatment chamber 12 after a short intake and mixing phase becomes. Thereafter, the mixing operation is restarted so that the water level in the pre-treatment chamber 12 falls to the minimum level, air is introduced and the communicating tube in the connecting line 48 is interrupted.

A sludge recirculation according to this principle can not take place if no sewage has flowed into the pretreatment chamber 12 after a pumping-off operation. This can occur, for example, if the operator temporarily does not use the small wastewater treatment plant 10 due to absence. Since no sludge growth takes place in this case due to the lack of nutrients for the microorganisms, this is an advantage of the system. However, in systems known from the prior art, sludge recirculation usually takes place by pumping operations, which must be controlled by the system controller. In this case, errors can occur which are avoided by the small wastewater treatment plant 10 according to the invention.

Switching between the opening and closing states of the first outlet 36 and the second outlet 42 can be realized in a particularly advantageous manner by a directional control valve 34, as illustrated, for example, in FIG. 5. This directional control valve 34 comprises a relative to the horizontal plane inclined tube 70, in the lower end 72 in a starting position a ball 74 rests, which constitutes a valve body. The inner diameter of the tube 70 is sized so that the ball 74 can be carried freely therein. The starting position is determined by a stop 76 at the lower end of the tube 70, on which the ball 74 rests. This end 72 is connected to the pressure side of the submersible pump 28 and represents the inlet of the valve 34. The upper tube end 78 is narrowed and forms a valve seat 80, which is closed by the ball 74. Below the upper end of the pipe 78 branches from the pipe 70 from a secondary line 82 which is vertical and a second valve seat 84 in the form of a taper of the cross section of the secondary line 82 comprises. In the secondary line 82, a float 86 is arranged, which can move freely through the second valve seat 84 therethrough.

Fig. 5 shows the directional control valve 34 in a non-pressurized position in which no flow pressure is generated by the submersible pump 28. The ball 74 is then due to its own weight on the stop 76 in its rest position. Both valve seats 80,84 are open. When the submersible pump 28 starts, a volumetric flow and a flow pressure are generated in the directional valve 34, which drives the ball 74 to the upper end of the pipe 78 and closes the first valve seat 80. In this first closure position, the second valve seat 84 is opened, and the water sucked by the submersible pump 28 can flow through the pipe 70 and through the secondary pipe 82. In the installed position of the embodiment proposed here, the upper first valve seat 80 forms the first outlet 36 of the directional valve 34, while the lower second valve seat 84 forms the second outlet 42. Thus, in the first closed position, the mixing line 38 is closed while the discharge line 44 is open. Optionally, the first valve seat 80 may also form the second outlet 42, while the second valve seat 84 represents the first outlet 36.

When the submersible pump 28 is turned off, the directional control valve 34 is de-energized, and the ball 74 may roll down within the tube 70 and release the first valve seat 80. It falls or rolls until the branch of the secondary line 82 in a position from which it is pressed by a renewed flow pressure, which is built up by the submersible pump 28 when switched on again, by pushing down the float 86 against the second valve seat 84 and here a second closure position occupies, in which the first valve seat 80 is opened. If the submersible pump 28 is switched off again, the float 86 drives the ball 74 gradually back up into a position from which it can automatically go back to its rest position on the stop 76 by its weight. As a result of the directional control valve 34 proposed here, the first valve seat 80 and the second valve seat 84 can be closed successively by first setting up the submersible pump 28 to exert pressure on the ball 74 against the first valve seat 80 in order to be used in the present connection type the first valve seat 80 forms the first outlet 36 and the second valve seat 84, the second outlet 42 to promote sewage through the drain line 44, then the submersible pump 28 is briefly turned off, so that the ball 74 may fall back to the secondary line 82 to at subsequent restarting the submersible pump 28 down to be pressed into the second valve seat 84 for closing it. That is, the directional control valve 34 may be operated to immediately follow a purging cycle with a charge and aeration cycle. Optionally, by briefly starting the submersible pump 28, pausing and repeatedly starting the pump to close the second outlet 42, an aeration cycle may be started first. The duration of the first pump surge is advantageously to be dimensioned so that no sewage sludge mixture accidentally gets into the drain line 44. External switching devices are not provided, and the directional control valve 34 is controlled exclusively by the inlet-side pressure built up by the submersible pump 28.

Fig. 6 shows an alternative embodiment of such a directional control valve 90. This also includes an inclined tube 70, at its lower inlet-side end 72, a stop 76 is provided which determines the rest position of a ball 74 as a valve body, as in the already previously described embodiment. The upper end 78 of this tube 70 represents the first valve seat 80. The secondary line 92, which branches off at the bottom of the tube 70, however, is formed by a tube which is angled slightly upwards relative to the horizontal and with the tube 70 an acute Includes angle. The end of the secondary line 92 forms the second valve seat 84. In the vicinity of the valve seats 80,84, the tubes 70,92 are connected by a connecting pipe section 94 which is approximately perpendicular and connects the tubes 70,92 to a triangle. When starting the submersible pump 28 in the position shown in Fig. 6, the

Ball 74 is pressed from the rest position along the tube 70 in the upper first valve seat 80 and closes it, as in the previously described embodiment. If the flow pressure drops, the ball 74 can roll back into the connecting line 94 and fall into the secondary line 92. When the pump 28 starts again and generates a flow pressure, the ball 74 is pressed into the lower second valve seat 84. If the submersible pump 28 is switched off again, the ball 74 automatically rolls back into its rest position thanks to the inclination of the secondary line 92. Also in this embodiment of the directional control valve 90, the switching from the emptying operation to the loading and venting by the submersible pump 28 already described in a connection type is possible, in which the first valve seat 80 represents the first outlet 36 and the second valve seat 84, the second outlet 42 which is connected to the drain line 44.

FIG. 7 shows an alternative embodiment of an emptying line 44, to which a branch line for pressure equalization and for optional sludge recirculation is connected in the pre-clarification chamber 12. This variant is useful in systems without hydraulically separate Vorklärkammer 12, in which the wastewater in a free fall through openings or via an overflow of the partition wall 22 from the primary chamber 12 flows into the clearing chamber 14. In this branch line is a vertical tube 100 having a check valve 104 in a lower portion 102, which is formed by a valve seat 106 and a ball 108 disposed therebelow, which rests in the open valve position on a stop 10 1. If the discharge line 44 pressurized, first wastewater is pushed through the tube 100 upwards out of a mouth 1 12 until the also pushed upwards ball 108 reaches the valve seat 106 and the check valve 104 closes. As a result, at the startup of the submersible pump 28, a sludge-containing waste water surge is first removed through the pipe 100. If one directs the mouth 1 12 in the pre-treatment chamber 12, excess sludge, which is sucked in by the submersible pump 28, can be discharged through the tube 100 in a surge-like manner. After closing the valve 104, the subsequent clear water in the discharge line 44 is conveyed into the clear water outlet 26. Optionally, a float 1 14 can be arranged in the tube 100, which is movable up and down in accordance with the level in the clarification chamber 14. Through an opening 1 16 in the tube wall above the check valve 104 can ensure that within the tube 100, the same water level prevails as in the clarifier 14. Above the opening 116 is a switch 1 18, which is actuated when the level so far sinks that the float 1 14 with its lower end to the switch 1 18 encounters. As a result, a function can be triggered, such as the renewed supply of wastewater from the primary clarification chamber 12.

Claims

1. biological clarifier (10) with at least one clarification chamber (14) and a in the clarification chamber (14) arranged submersible pump (28) for the treatment of wastewater, characterized in that the pressure side of the submersible pump (28) to the inlet of a directional control valve (34 , 90) is connected to two outlets, of which a first outlet (36) is connected to a mixing line (38) opening into the clarification chamber (14) and a second outlet (42) is connected to a drainage line (44), which opens into a clear water outlet (26).

2. biological clarifier according to claim 1, characterized by a pre-clearing chamber (12) into which one of the mixing line (38) branches off connecting line (48) opens.

3. biological clarifier according to claim 2, characterized marked, that the connecting line (48) for sucking waste water and / or air from the pre-clearing chamber (12) is provided.

4. biological clarifier according to claim 3, marked thereby, that the free end of the connecting line (48) has a bell-shaped

Floating body (52), whose lower edge is located below the waste water level of Vorklärkammer (12) and which has at least one opening (62) at a height above its lower edge.

5. biological clarifier according to claim 4, characterized in that in the Vorklärkammer (12) an upper and a lower stop (56,58) for limiting the up and down movement of the floating body (52) are arranged.

6. biological clarifier according to one of claims 2 to 5, characterized in that the connecting line (48) for returning sludge from the clarification chamber (14) is provided in the pre-clearing chamber (12).

7. biological clarifier according to one of claims 2 to 5, characterized in that from the discharge line (44), a sludge recirculation line (100) emanates, which opens into the primary clarification chamber (12).

8. biological clarifier according to any one of the preceding claims, characterized in that the directional control valve (34,90) comprises a valve body (74) for selectively closing the first or the second outlet, which outlets each one through the valve body (74) closable valve seat ( 80,84),

in that, for closing one of the two outlets, the valve body (74) can be pressed by flow pressure into the first valve seat (80) from an initial position at the inlet of the directional control valve (34, 90),

and that the valve body (74) from the first valve seat (80) in the flowless valve state can reach a position from which the valve body (74) by flow pressure for closing the other outlet in the second valve seat (84) can be pressed.

9. biological clarifier according to claim 8, characterized in that the valve body (74) from the first valve seat (80) for closing the other outlet by gravity can reach a position from which he by flow pressure in the second valve seat (84) is depressible.

10. biological clarifier according to claim 9, characterized in that the directional control valve (34,90) comprises an inclined tube (70), in whose lower end the starting position of the valve body (74) is located and at the upper end of the first valve seat (80 ) is arranged.

1 1. biological clarifier according to claim 10, characterized in that of the inclined pipe (70) below the first valve seat (80) branches off a secondary line (82,92), in which the second valve seat (84) is arranged net.

12. biological clarifier according to claim 1 1, characterized in that the secondary line (82) branches off approximately vertically from the inclined tube (70) downwards.

13. Biological clarifier according to one of claims 8 to 12, characterized by means for conveying the valve body (74) from the second valve seat (84) back to the starting position or in a position from which the valve body (74) automatically return to the starting position can.

14. biological clarifier according to claim 13 in conjunction with claim 11, characterized in that the means comprise a in the secondary line (82) in the region of the second valve seat (84) arranged float (86) whose cross-section is dimensioned such that it second valve seat (84) can happen.

15. biological clarifier according to claim 1 1, characterized in that the secondary line (92) relative to the horizontal plane is angled slightly upwards and that the secondary line (92) and the inclined tube (70) in the vicinity of the valve seats (80,84) additionally connected by an at least approximately vertical connecting pipe section (94).

16. Biological clarifier according to one of the preceding claims 8 to 15, characterized in that the valve body (74) is a ball.

17. Biological clarifier according to one of the preceding claims 8 to 16, characterized in that the first valve seat (80) corresponds to the first outlet (36) of the directional control valve (34, 90) and the second valve seat (84) corresponds to the second outlet (42). ,