WO1999057068A1 - Fully biological premises sewage treatment installation - Google Patents

Abstract

The invention relates to a fully biological premises sewage treatment installation, comprising two activated sludge tanks (4, 5). Sewage is fed (7) into the first tank and the clarified water is withdrawn by suction (8) from the second tank. Each tank has an aeration device (9, 11) and means (10) for transferring the contents of one chamber into the other. Material is fed back from the second chamber into the first via an opening or a line with an angled end piece, said end piece being fitted in such a way that it can turn. At least one chamber has a floor with adjustable height and inclination. A third chamber for collecting sludge can be sectioned off in the housing for those installations which cannot be emptied very frequently.

Description

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Fully biological small sewage treatment plant. The invention relates to a fully biological small wastewater treatment plant with two aeration tanks, in which one aeration tank the inlet of the wastewater to be cleaned and from the other aeration tank the removal of the clear water takes place, with at least one aeration device and devices for at least partially transferring the filling of the one aeration chamber into the other.

There are biological wastewater treatment plants, also known for smaller amounts of wastewater to be treated. Such a system is described, for example, in the publication: "Deutscher Alpen Verein" (DAV), issue 1/97 under the title: "New revolutionary wastewater treatment process for the Meißner Haus". It consists of an aeration tank, a sedimentation and circulation pool as well as a sludge storage in a structural unit. In this known arrangement, the waste water is supplied via a shaft arranged in the activation chamber via a cutting wheel pump, the overflow into the sedimentation chamber takes place via an open shaft, so that a communicating system is created between the activation chamber and the sedimentation chamber. Sludge is transferred to the sludge storage via a floating pump arranged in rails. With this arrangement, the clear water is drawn off from the sedimentation chamber. What is essential in this known method is the connection of the activation tank and the sedi Mentation basin in such a way that they behave like hydraulically communicating vessels. In the aeration tank, the aeration devices and in the sedimentation tank are the devices for the scamming circuit with guide walls.

This known arrangement has the advantage of a high cleaning performance with a small volume requirement, however, a disadvantage of this arrangement is that precisely due to the supposed advantage of the hydraulically communicating arrangement of the two chambers, in each process step in one chamber there is an effect in the other chamber, so that e.g. in the event of a higher inflow into the activation chamber due to consumption, the water level in the sedimentation chamber changes automatically and possibly leads to an overflow, although the desired residence time in the sedimentation chamber has not yet been reached. This can also lead to an undesirable circulation of the content of the sedimentation chamber, which disturbs the sedimentation. Furthermore, the necessary phases of cleaning are carried out separately from each other. This known arrangement also requires a higher monitoring effort.

On the basis of the known prior art, the invention is based on the object of demonstrating a fully biological small sewage treatment plant which, with particularly low construction costs and volume, works largely independently of maintenance and leads to a biologically stabilized sludge. The arrangement should also be mountable in the workshop, so that it can only be placed in a prepared pit - if arranged in the ground - or on a level floor -3- introduced or attached and the supply connections must be connected. The phases of fully biological purification are to be run through one after the other.

The solution to the problem results in a fully biological small sewage treatment plant with the characteristic that two aeration tanks are formed in a common, preferably round container by a partition, each with an aeration device and in the partition a return between the second and the first aeration chamber and a device in the first aeration chamber is arranged for transferring water into the second activation chamber. With this arrangement, the fully biological cleaning phases can be run through one after the other. This is achieved by the arrangement according to the invention of two activation chambers connected in series and by the arrangement of the return from the second to the first activation tank and the arrangement of one ventilation device in each of the two activation chambers. For example, two to four or even more cycles can be run through each day. In the first phase of a cycle, intermittent ventilation takes place, in which the wastewater is enriched with oxygen and at the same time mixed and circulated. As a rule, the solids in the wastewater are crushed and broken down by the circulation. The wastewater is fed from the first chamber into the second chamber via a rake or sieve device, for example through an air lifter. In the case of special loads, a cutting wheel pump can be used as an overfilling device. The flocculation process takes place during the pause of ventilation -4- activated sludge. This ensures optimal sedimentation properties of the activated sludge. In the second phase of the cycle, sedimentation takes about one hour. During this time, a clear water zone of purified wastewater forms in the upper area of the basin. This is withdrawn from the second basin using a submersible pump and fed into the drain. The particular advantage is that this system only produces biologically stabilized sludge that can be used directly. If, for example, mechanical pre-cleaning from existing stock is carried out, biologically stabilized sludge is not the only product. This means that there is no need for a rake or sieve, so that the excess sludge that is fed into soil forms a closed system in which humus is ultimately produced on the property. It has been shown that 2 to 4 cycles per day are sufficient for all the water of conventional small systems. In this system, the return flow from the aeration tank two into the aeration tank one can change and adapt the overflow height in that a pipe with an angled and rotatably mounted end piece is provided as an overflow, the angled part being pivotable by up to 90 degrees. With a corresponding length of the angled, rotatably arranged part, this variation of the overflow height is possible within wide limits.

According to a continuation, a clear water pump is arranged in the second activation tank, the inlet of which preferably consists of a flexible pipe with discharge openings in the upper region followed by a float. The immersion depth of the float can be about the height of the -5- end piece provided with inlet openings. The discharge openings in the flexible hose are therefore preferably arranged in the metal pipe end piece which is inserted into the flexible pipe and to which the float is attached.

The arrangement of a cutting wheel pump in the wastewater conveying device between the first and the second activation chamber, which is provided in accordance with a further embodiment, is appropriate when greater contamination in the wastewater is to be expected. In normal use, the circulation of the wastewater is sufficient to shred coarse materials such as textiles or paper. This pump is only put into operation after the sedimentation is complete and is time and / or level controlled.

According to a very particularly expedient development, a floor which is adjustable both in its inclination and in its height is arranged in at least one activation chamber. These floors are adapted to the corresponding chamber so that they can be moved easily. This applies both to swiveling around an axis, whereby the inclination of the floor can be changed, as well as for a parallel height adjustment. The floors are each free in the corresponding aeration tank. In the case of a circular segment shape, an adjustment element, for example a cable pull, is attached to at least one of the straight sides, another element approximately in the middle of the segment circumference. To change the position of the floor, its distance from the floor of the activation chamber, all adjustment elements are shortened, which leads to a lifting of the floor. To change the inclination of the floor, the adjustment element on the circular arc of the segment is shortened. Thereby -6- The straight sides of the floor, which run at right angles to one another, remain in their position and only the, for example, quarter-circular section of the floor is raised, so that the desired inclination arises. A ScMamm collecting space can be formed through this floor below the floor. By changing the inclination, a gap is created between the housing and the floor in the raised area, through which the sludge can enter the part of the activation chamber which is located below the floor. This space can be enlarged by adjusting the height of the inclined floor. This means that the system can always be operated with the permissible dry matter content. This continuation according to the invention can also be used in all other comparable plants independently of the fully biological small sewage treatment plant described.

Since the ventilation device, when it is arranged on the floor of the chamber, whirls up the sludge accumulated there when the ventilation is switched on, the ventilation must be arranged on the movable floor in the floor used, so that the sludge can thicken below the floor. With the used and possibly raised and inclined floor, there is a swirling with oxygen entry above this floor. In order to achieve a directed penetration of the whirled-up sludge into the activation tank, flow guidance elements are arranged on the bottom of the respective activation chamber below the bottom, which is variable in its position. These elements can be made of plastic and placed in the chamber. In the simplest case, guiding elements are sufficient, the edges -7- "rounds off" between the bottom of the activated sludge tank and the housing wall or the partition wall or partitions. Of course, empirically determined radii can also be formed, for example parabolic curves. With this a dosed whirling up can be achieved. In the case of a sludge accumulation in the ScMamm collecting space below the floor, this sludge fraction can be drawn off in a known manner, for example by means of a hose cart, or can be conveyed to a grounding stage by means of a pump. The particular advantage of these guide elements is that less air is required for the ventilation process.

Because the plant according to the invention is relatively small, a sludge collecting space can also be partitioned off. From time to time, the excess sludge can thus be drawn off from the second activation chamber into this space. This creates a particularly compact and autonomous system from which sludge only has to be run at very long intervals. A pre-clarifier can also be installed upstream. In this case, the rake or the sieve or the cutting device of the cutting wheel pump can of course be dispensed with. Then, however, the entire sludge is not stabilized.

In FIGS. 1 and 2, an exemplary embodiment of a plant with a sludge stacking space is simplified and shown schematically and is described below. For the preferred embodiment of the invention with only the two activation chambers, the sludge stacking space is eliminated. 1 shows a plant with a sludge stacking space in longitudinal section, -8- Fig. 2 shows the associated cross section.

In the embodiment, two partitions 2, 3 are drawn into the container 1, so that three chambers 4, 5 and 6 are formed. The chamber 4 is the first activation chamber with the water inlet 7, the chamber 5 is the second activation chamber with the clear water outlet 8, the chamber 6, which is only required in special cases, is the sludge stacking space. The wastewater is fed into the first activation chamber 4 via the wastewater inlet 7. In this chamber 4, an aerator 9 is arranged, preferably removable. The activation chamber 4 also has a device 10 for transferring pre-cleaned waste water into the activation chamber 5. This device 10 has a mammoth pump and a section 12 projecting into the activation chamber 5, furthermore a cloudy water overflow 13 which penetrates the partition 2. The device 10 has inlet slots and is at least partially surrounded by a rake such that no larger solids can get into the activation chamber 5. Furthermore, a return line formed from an angled tube 14 is arranged between the activation chamber 4 and the activation chamber 5 and penetrates the dividing wall 3. A removable aerator 11 is also arranged in the activation chamber 5. In the activation chamber 5 there is also an excess sludge discharge 16 projecting into the chamber 6, the sludge stacking space 6. - 9 -

The turbid water overflow 13 serves to transport turbid water back from the sludge stacking space 6 into the first activation chamber 4 if the liquid level in the sludge stacking space 6 rises too high. The excess sludge discharge 16, which is equipped with a sludge pump, serves to transfer excess sludge from the second

Activation chamber 5 into the sludge stacking space 6. A pump 15, preferably designed as a submersible pump, in each case ensures that clarified water is pumped out of the small sewage treatment plant in a sedimentation phase. The floating extraction line of the pump 15 enables the clarified water to be sucked in as far as possible from the top level of the scarf in the second activation chamber 5; the pumping can be started earlier after the start of the sedimentation phase. As a result of the return pipe 14 between the second activation chamber 5 and the first activation chamber 4, activated sludge repeatedly flows from the second chamber 5 into the first chamber 4 in order not to allow an undesirably large drop in the biological activity of the activated sludge there.

The inlet slots in the outer tube of the mammoth pump 10, which works with air injection into the inner tube near its lower end, end a considerable distance, e.g. B. a good 1 m, above the bottom of the container 1, so that a minimum liquid level is defined in the first chamber 4.

Instead of adjustable in chambers 4 and 5 as described above

Arranging floors, you can also provide to make only the respective ventilation device in the relevant chamber distributable in height. If z. B. in the first chamber 4 has deposited a larger amount of settling sludge below, which you do not want to whirl up in the ventilation phases, you can use the one there

Raise the aeration device a bit, raise it again some time (e.g. weeks) later, etc. It is then sufficient to rarely remove the settling sludge in the first chamber 4, e.g. B. after 1 to 2 years to empty. The same procedure can be followed in the second chamber. - 10 -

A partition 3 common to these chambers 4, 5 need not necessarily be present between the two activation chambers 4, 5. One could also set up two separate activation chambers 4, 5 in close spatial proximity. However, it is important that the

Water transfer device 10 and the return 14 connect the two chambers 4, 5 together.

From the end of the cycles and from the beginning of the cycle sections, the small sewage treatment plant can be designed to be time-controlled, level-controlled or, in a combined manner, time and level-controlled.

Claims

-11 -patent claims: 1. Fully biological small wastewater treatment plant with two aeration tanks, in which one aeration tank is the inlet of the wastewater to be treated and from the other aeration tank the clear water is withdrawn, with at least one aeration device and devices for transferring at least part of the filling of the one aeration chamber into the other , characterized in that two activation tanks (4, 5) are formed in a common, preferably round container (1) by a partition (3), each with an aeration device (9, 11) and in the partition (3) a return between the second and a device (10) for transferring water into the second activation chamber (5) is arranged in the first activation chamber (5, 4) and in the first activation chamber (4). 2. Fully biological small sewage treatment plant according to claim 1, characterized in that the return between the second activation chamber (5) and the first activation chamber (4) is formed by an angled pipe (14). 3. Fully biological small sewage treatment plant according to claim 1 or 2, characterized in that the device (10) for transferring waste water from the first into the second activation chamber with its suction opening near the bottom of the activation chamber (4) and is at least partially surrounded by a cleaning rake and has extraction slots in the upper area. 4. Fully biological small sewage treatment plant according to claim 3, characterized in that the transfer device (10) has a mammoth pump. 5. Fully biological small sewage treatment plant according to claim 1, characterized in that a pump (15) is arranged in the second activation tank (5), the inlet of which consists of a flexible tube with discharge openings in the upper area with subsequent float. 6. Fully biological small sewage treatment plant according to one of claims 1 to 5, characterized in that the device (10) for conveying waste water from the first (4) in the second activation chamber (5) has a cutting wheel pump. 7. Fully biological small wastewater treatment plant according to one of claims 1 to 6, characterized in that in both at least one of the activation chambers (4, 5) a floor which is adjustable both in terms of its inclination and its installation height is arranged. 8. Fully biological small sewage treatment plant according to one of claims 1 to 5, characterized in that flow control elements are arranged at the bottom of the activation chamber. 9. Fully biological small sewage treatment plant according to claim 7, characterized in that the change in position of the floor in its installation height and / or its inclination is carried out by separately acting adjusting elements. 10. Fully biological small sewage treatment plant according to claim 2, characterized in that the angled section of the return pipe (14) is rotatably arranged.