EP1567454A2

EP1567454A2 - Method for purifying waste water and corresponding waste water purification installation

Info

Publication number: EP1567454A2
Application number: EP03799470A
Authority: EP
Inventors: Walter Herding; Urs Herding; Kurt Palz; Rainer THÜRAUF
Original assignee: Herding GmbH Filtertechnik
Current assignee: Herding GmbH Filtertechnik
Priority date: 2002-12-05
Filing date: 2003-12-04
Publication date: 2005-08-31
Also published as: WO2004050566A3; AU2003299299A1; AU2003299299A8; WO2004050566A2; DE10256918A1

Abstract

The invention relates to a method for purifying waste water, one stage of said purification method involving the aerobic treatment of waste water with micro-organisms, forming excess mud. The inventive method is characterised in that: (a) at least part of the excess mud (18) is supplied to a jet collision reactor (20) and is discharged from the same by means of a gas flow (28), as a homogenised, solubilised substrate; and (b) at least one large part of the substrate is either recirculated for the aerobic treatment of the waste water, or is supplied to a high-performance anaerobic reactor (40) for producing biogas, or part of the substrate is recirculated for the aerobic treatment and part is supplied to the high-performance anaerobic reactor (40) for producing biogas.

Description

Process for the treatment of waste water with formation of excess sludge and corresponding waste water treatment plant

The invention relates, according to a first aspect, to a process for the treatment of waste water, wherein an aerobic treatment of the waste water with microorganisms with the formation of excess sludge is one of the stages of the treatment process.

At present, wastewater is mostly treated by subjecting it to biological treatment, often after a rough mechanical pre-treatment, with a particularly important stage being the aerobic treatment of the wastewater with microorganisms, with the formation of excess sludge. Bacteria are suitable microorganisms for breaking down organic contaminants in the waste water. For aerobic treatment, artificial aeration of the wastewater is e.g. B. required by blowing air into the lower region of a waste water volume. The excess sludge resulting from the decomposition of organic contaminants in most cases drops to the bottom of the waste water volume; there are also types of sludge that float to the surface. Biodegradation causes excess sludge to form CO ₂ , which escapes to the outside. In many cases, biological clarification is carried out in several stages (e.g. first aeration stage, second aeration stage, secondary clarification) or in succession in the same basin (batch process).

The excess sludge formed during the aerobic treatment of the wastewater with microorganisms is a problem. It occurs in large quantities and is practically liquid with a high water content. The excess sludge usually contains germs and is mostly largely odorless. So far, the excess sludge has to be removed in some way. One of the common procedures is dewatering and subsequent digestion in a digester. The resulting sludge, which is no longer particularly rich in water, has so far been applied to fields where it is used as fertilizer and soil loosening agent. This type of disposal is increasingly regarded as less than optimal because the digested sludge - depending on the origin of the wastewater - contains inorganic, potentially toxic substances (e.g. heavy metal compounds, pharmaceutical residues). An alternative way of sludge removal is incineration, for example in a waste incineration plant, usually after dewatering, rotting and drying, if necessary. This is evidently a very expensive way of removing sludge. Instead of burning the sludge, it can be deposited in a landfill. This is also expensive.

The invention has for its object to show a way with which the amount of excess sludge to be ultimately removed can be reduced very significantly. This leads to a reduction in the cost of wastewater treatment because a much smaller amount of sludge ultimately has to be disposed of and transported for this.

According to the first aspect of the invention, this object is achieved in the method mentioned at the outset by

(a) that at least part of the excess sludge is fed to a jet collision reactor and discharged from it by means of a gas stream as a homogenized, digested substrate; (b) and that at least a majority of the substrate -

- is either recirculated to the aerobic treatment of the waste water

- or to a high-performance anaerobic reactor for the production of biogas - or partly to the aerobic treatment of the waste water and partly to the high-performance anaerobic reactor for producing biogas. A jet collision reactor with gas flow discharge is known per se, see WO 00/61275. In the known jet collision reactor, two or three liquid jets are brought together at high pressure at a collision point in the center of the reactor. Particles contained in the liquid jets are very effectively comminuted by the high forces acting on the collision. The gas stream flowing at right angles to the plane of the liquid jets in the known reactor discharges the collision products together with the liquid of the liquid jets from the reactor. The actual reactor room contains no moving parts at all, it cleans itself through the gas flow.

The known jet collision reactor is intended for the production of very small particles, in particular color pigments and ceramic particles. Dispersing, homogenizing and emulsifying in medical products, cosmetic products, pharmaceutical products and food products has hitherto been envisaged as a further area of application.

In the method according to the invention, the cell walls of the microorganisms are largely destroyed in the jet collision reactor. The cell content is released and the homogenized, digested substrate thus formed can then be further processed, whether by recirculation to aerobic treatment with microorganisms or in a downstream anaerobic reactor. In the case of recirculation, the homogenized, digested substrate discharged by means of a gas stream can be treated very well (again) aerobically with microorganisms. In the case of subsequent treatment in an anaerobic reactor, the substrate can be converted much more effectively into high-quality biogas, which consists of a very high percentage of CH.

The process according to the invention can be operated in such a way that ultimately only extremely small amounts are generated from excess sludge to be removed outside the sewage treatment plant. After - possibly multiple - recirculation, practically all organic impurities are removed by the microorganisms, ie essentially oxidized to CO ₂ . Not through the microorganisms degradable impurities, in particular inorganic impurities such as earth or sand constituents of the sewage ^■ sers must naturally be branched off and removed. The process is preferably carried out in such a way that less than 10% of the excess sludge formed by the aerobic treatment, most preferably less than 5%, is removed and removed to the outside.

The recirculation of homogenized, digested substrate according to the invention also has the effect that the sludge load increases at the corresponding aerobic treatment stage. This increases the efficiency of the sewage treatment plant.

In conventional digestion towers, a gas with a relatively low calorific value is generated, which contains CH, but CO ₂ in a not insignificant amount and other components. In the invention, however, a comparatively high-quality biogas with a high content of CH can be produced from the homogenized, digested substrate in a high-performance anaerobic reactor, and the residence time in the high-performance anaerobic reactor can be shorter than in a conventional digestion tower. This is an essential factor in reducing investment costs.

As has already been mentioned above in the representation of the solution according to the invention, the entire excess sludge from the aerobic wastewater treatment does not necessarily have to be fed to the jet collision reactor in the invention. Depending on the objective, you can also be satisfied with treating only part of the excess sludge in this way and removing the remaining part in a conventional manner. It has also already been expressed above that it is not absolutely necessary to recirculate the entire, homogenized, digested substrate discharged by means of a gas stream to the aerobic treatment and / or to the high-performance anaerobic reactor. Part of the substrate can also be removed from the system and disposed of, for example, in conventional catfish. The outlet of the high-performance anaerobic reactor is preferably fed to the inlet of the sewage treatment plant, so that it goes through the normal clarification, including the aerobic stage. The discharge of the high-performance anaerobic reactor normally contains a certain amount of dead biomass, which is carried away in varying amounts by the internals of the reactor. Depending on the particular application, it may be necessary to backwash the high-performance anaerobic reactor from time to time in order to specifically remove dead biomass from the internals.

145

It is emphasized that the word "gas flow" is not intended to mean that _; this stream introduced into the tranikoiiιsιonsreaκtor is a 100% pure gas stream. For example, certain solid parts or liquid parts could be contained, which however, if present, normally make up a small part. Examples are given later.

The gas stream is preferably an air stream or an air stream enriched with oxygen or an ozone stream or an air stream enriched with ozone, with the foregoing also relating to solids and

155 parts of liquid apply. Combinations of the types of gas mentioned are also possible, e.g. Air that is enriched with both oxygen and ozone. The air can be normal ambient air. The combination of the gaseous discharge medium and substrate according to the invention, which by default has mainly a liquid physical state, is particularly useful in the case of

Circulation to the aerobic treatment is a considerable advantage because gas, in particular air, is introduced into a clarifier in the most intensive mixing, which promotes aerobic treatment with microorganisms. The enrichment of air with oxygen and / or ozone leads to an acceleration of aerobic treatment with microorganisms; the same goes for

165 for working with an ozone stream. *

The jets of the excess sludge to be treated are preferably blasted into the jet collision reactor at an initial pressure of 40 to 160 bar and brought to collision there. To generate a high jet speed, the excess sludge to be treated is sprayed through nozzle-like narrow channels pressed. Said range of (static) pressure upstream of these channels is lower than the pressure typically used in jet collision reactors, but it has been found that said range of pressure does a good job of homogenizing and digesting the excess sludge 175.

The excess sludge to be treated is preferably first fed to a sludge reservoir and from there to the jet collision reactor. In this way, a uniform, continuous feed of the 180-jet collision reactor can be achieved, which also results in a less fluctuating consistency of the excess sludge fed to the reactor.

The excess sludge to be treated in the reactor can originate from several 185 clarification stages or stages. A particularly preferred process consists in that the excess sludge partly comes from an activated sludge stage (or several activated sludge stages) and partly from a secondary clarification stage.

190 There are cases in which particularly favorable processes result when a considered partial volume of the excess sludge to be treated is treated in several passes in succession by the jet collision reactor. It may be cheaper to choose the pressure and jet velocities instead of a single pass through the reactor

Adequate homogenization and disintegration takes place, rather to work with a lower energy concentration in the beam collision point and instead of this with several passes. This saves energy in particular for the pump (s) of the jet collision reactor. The treatment in several runs in succession can either take place in such a way that a certain volume

200 pumps several times in succession through the reactor and then brings this volume away from the reactor and replaced by the next volume. Alternatively, you can work with recirculation through the ReakTόr and continuously branch off a subset that is no longer recirculated. In this case, too makes a static average of each partial volume more than one pass through 205 the reactor.

The method according to the invention can be carried out as a method over a plurality of cleaning stages which are locally adjacent to one another. Mechanical pre-cleaning, e.g. with a rake to make big

Separate 210 things like plastic bags, branches or the like, and then one or more activated sludge stages, and finally a secondary clarification stage. Alternatively, the process can be carried out as a batch process for at least some of the clarification stages, with several stages of the process taking place in succession at a location under consideration. A typical example

215 would be a mechanical pre-cleaning stage at an upstream location, then an activated sludge basin, in which an activation phase with air supply and a post-treatment stage without air supply take place one after the other. The batch processes are particularly favorable for smaller amounts of waste water.

220 The method according to the invention is also well suited for combination with an upstream membrane filtration stage. In the membrane filtration stage, it is possible - particularly cheaply in the case of waste water not loaded with particularly high loads - to concentrate and then carry out the aerobic treatment with microorganisms. This reduces the amount of wastewater that

225 must be treated aerobically.

The invention further relates, according to a second aspect, to a method for treating excess sludge from the treatment of waste water, characterized in that the excess sludge to be treated is a

230 jet collision reactor supplied and discharged from it by means of a gas stream as a homogenized, digested substrate. This second aspect of the invention is, as it were, the centerpiece of the overall process described so far. The previous statements, and especially the previously described preferred features, do not only apply to the

235 whole method but also for the method according to the second aspect of the invention. Another object of the invention is, according to a third aspect, a wastewater treatment plant which has a basin in which aerobic treatment of wastewater with microorganisms can be carried out with the formation of excess sludge, characterized in that

(a) that a jet collision reactor with gas flow discharge of the collision product is provided, the jet collision reactor with the aerobic

245 treatment tanks for transferring at least part of the excess sludge;

(b) and that for at least a large part of the collision product stream

- The jet collision reactor for recirculation is connected to the Aefob treatment basin 250 - and / or the jet collision reactor is connected to a high-performance anaerobic reactor for generating biogas.

The wastewater treatment plant according to the invention evidently achieves the object mentioned above of reducing the amount of excess sludge to be disposed of and has device features which correspond in terms of device to the features of the method according to the invention. With the wastewater treatment plant according to the invention, the wastewater treatment plant according to the invention can be carried out without, however, the wastewater treatment plant according to the invention being limited to this.

260

All of the preferred features described further above in connection with the wastewater treatment process according to the invention are, in terms of the device, also preferred features of the wastewater treatment plant according to the invention. In addition, the following is pointed out:

265

The jet collision reactor is preferably equipped with nozzles for jet generation which have a diameter of 1 to 5 mm, preferably 1.5 to 4 mm.

270 Preferably, the jet collision reactor is assigned at least one membrane pump for generating the pressure for jet generation. This type of Pump is characterized by robustness. The jet collision reactor is preferably assigned a separate pump for each jet nozzle. This results in direct pressure generation close to the jet nozzle in question and does not have to be a disadvantage from the point of view of the manufacturing costs. But the alternative is also possible, namely a common pump for all jet nozzles, which is connected to the jet nozzles via a distributor line.

The high-performance anaerobic reactor, which is connected to the jet collision reactor, preferably contains internals for immobilizing microorganisms. This feature helps to design the anaerobic reactor with a high throughput.

Another object of the invention is, according to a fourth aspect, a jet collision reactor with gas stream discharge of the collision product, characterized in that it is designed and intended for treating excess sludge from the treatment of waste water. One could alternatively also say that this object of the invention is the use of a jet collision reactor with gas flow discharge of the collision product for treating 290 excess sludge.

It is emphasized that the preferred features of the wastewater clarification process according to the invention, as described in the device, are also preferred features of the jet collision reactor 295 according to the invention. The preferred features of the wastewater treatment plant according to the invention described above are also preferred features of the jet collision reactor according to the invention.

The gas stream for discharging the homogenized, digested substrate should be fed to the jet collision reactor at such a pressure that the collision product is safely discharged from the reactor. There is also a dependency on the back pressure conditions behind the reactor. In most cases, a static pressure of up to 20 bar when feeding into the reactor will be sufficient.

305 Another object of the invention is, according to a fifth aspect, a method for clarifying a suspension of at least one organic waste, characterized in that

(a) that at least part of the suspension is fed to a jet collision reactor and is discharged from it by means of a gas stream as a homogenized, digested substrate;

(b) and that at least a large part of the substrate is fed to a high-performance anaerobic reactor for generating biogas.

315 Another object of the invention is, according to a sixth aspect, a method for treating a suspension of at least one organic waste material, characterized in that the suspension is fed to a jet collision reactor and extracted from it by means of a gas stream as a homogenized,

320 closed substrate is discharged.

Another object of the invention is, according to a seventh aspect

Sewage treatment plant for a suspension of at least one organic waste material, characterized, 325 (a) that a jet collision reactor with gas flow discharge of the collision product is provided;

(b) and that the beam collision reactor is connected to a high-performance anaerobic reactor for producing biogas for at least a large part of the collision product stream.

330

Another object of the invention is, according to an eighth aspect, a jet collision reactor with gas flow discharge of the collision product, characterized in that it is designed and intended for treating a suspension of at least one organic waste. One could alternatively also say that this object of the invention is the use of a jet collision reactor with gas flow discharge of the collision product for treating suspension of at least one organic waste. It is emphasized that the preferred features of the invention described above according to the first, second, third and fourth aspects are also preferred features of the invention according to the fifth, sixth, seventh and eighth aspects.

The most significant difference of the invention according to the fifth, sixth, seventh and eighth aspects compared to the invention according to the first, second, third and fourth aspect is that it is not an excess sludge from aerobic treatment of waste water that is treated, but a suspension of at least one organic waste material. In most cases this suspension can also be described as organically very highly contaminated wastewater; Such wastewater often comes from production plants. Illustrative examples include certain brewery production areas (waste water heavily contaminated with yeast residues) and the quasi-industrial processing of sugar cane (waste water contaminated with molasses-like residues).

355

Up to now, such suspensions or waste water have typically been treated in anaerobic tanks, where very long dwell times were required for a breakdown; Depending on the type of waste, two to four weeks are quite typical. By treating the suspension according to the invention, the required residence time, depending on the waste material, can be reduced to eight to 72 hours. A comparatively high-quality biogas with a high content of CH _{4 is} generated in the high-performance anaerobic reactor.

The discharge from the high-performance anaerobic reactor can be fed to a second part 365 of the sewage treatment plant, which has an aerobic stage, so that a finally clarified waste water is obtained on the spot. Depending on the circumstances of the individual case, it may also be possible to use the outlet from the high-performance anaerobic reactor with e.g. B. bring together municipal wastewater and clarify this mixed wastewater in a sewage treatment plant of a 370 or other usual structure. The invention and preferred developments of the invention are explained in more detail below with the aid of schematically illustrated exemplary embodiments. It shows:

375

Fig. 1 schematically shows a wastewater treatment plant with its main components and the most important material flows;

Fig. 2 schematically shows a section of a wastewater treatment plant of another 380 type; ,

3 schematically shows a beam collision reactor in section;

Fig. 4 schematically shows another wastewater treatment plant.

385

The wastewater treatment plant 2 shown in FIG. 1 has the following main components: pre-purification 4, first activation stage 6, second activation stage 8, secondary clarification stage 10, excess sludge storage 12, jet collision reactor 20. For the sake of brevity, the jet collision reactor 20 will now only be a 390 "reactor 20 ".

The wastewater 22 to be cleaned first passes through the preliminary cleaning 4, where first very coarse impurities such as sacks, plastic bags, branches, plastic bottles and the like are retained by mechanical rakes 24

395 will be. The pre-cleaning then contains a sand trap and a fine rake. The pre-cleaned waste water 22a runs to the first activation stage 6. The first activation stage 6 has a basin of suitable horizontal cross-sectional area and suitable height, in which bacteria are present for biodegrading organic contaminants in the waste water 22a. the

A pool, not shown, is assigned to 400 pools, with which large amounts of air can be blown into the lower area of the waste water present in the pool. Excess sludge is formed during the biological degradation of the organic contaminants, especially when the blower described is at a standstill and sinks to the bottom of the pool, 405 from where it is withdrawn at certain intervals and brought into the excess sludge storage 12.

The wastewater 22b, which has already been partially biologically clarified, passes from the first activation stage 6 to the second activation stage 8, which is quite analogous to that

410 first activation stage 6 is established. From the second activation stage 8, the wastewater 22c, which has now been further clarified, reaches the secondary clarification stage 10. This is a basin, on the bottom of which the residual amounts of excess sludge can settle. The basin of the second activation stage 8 and the basin of the secondary clarification stage 10 are also connected to the excess sludge reservoir 12.

415 sen, so that all excess sludge gets into this storage 12.

The clarified waste water 22d runs from the secondary clarification stage into a receiving water, e.g. a river.

420 Excess sludge 18 is fed to the reactor 20 from the sludge storage 12, continuously or in batches.

The reactor 20 is of a type which will be described in more detail below in connection with FIG. 3. At this point it is enough

425 to show that the reactor 20 has a sludge feed 24a or 24b on the left and right, diametrically opposite, each sludge feed being associated with a diaphragm pump 26a or 26b which can press the sludge into the reactor 20 at a pressure of 90 bar , The reactor 20 has an access opening at the top through which air 28 passes under a pressure of 6 bar

430 can be pressed into the reactor 20. At the bottom, the reactor 20 has an outlet opening through which the collision product is discharged in the air stream, see reference numeral 30.

As will be explained in more detail below, the discharged 435 stream 30 is a homogenized, digested substrate from the excess sludge, which is conveyed distributed in an air stream. The discharge stream 30 is recirculated to the lower region of the basin of the first activation stage 6. The substrate is there and in the second stage 8 is subjected to biological clarification again, and since the previous excess sludge has been homogenized and digested, biological degradation is possible. Ideally, all biodegradable material is biodegraded after recirculation, possibly also after multiple recirculation, so that no excess sludge has to be diverted to the outside and disposed of at all. In practice, however, this ideal goal is difficult to achieve, so that normally a certain proportion of the excess sludge, for example in the range from 0 to 10% of the excess sludge, is continuously diverted from the reservoir 12 to the outside.

450 So far, the sewage treatment plant 2 has been described in such a way that excess sludge from the sludge storage 12 is largely homogenized and digested in a single pass through the reactor 20 so that it can be biodegraded in the activation stages 6 and 8. This is one way of interpreting. A second possibility of interpretation is

455 that a share of e.g. 50% of the effluent stream 30 is recirculated into the sludge feed lines 24a, 24b, so that the excess sludge undergoes on average more than one pass through the reactor 20 before it is recirculated as substrate to the first activation stage 6. A third possibility is to multiply a sub-volume of excess sludge -

To have 460 others circulated through the reactor 20 and then to recirculate altogether to the first activation stage 6; then a sub-volume considered below is treated in this way. In this case, it is good to assign an intermediate tank to the reactor 20 so that the partial volume mentioned has an optimal size.

465

In Fig. 1, an alternative is shown in broken lines, how to further process the output stream 30 from the reactor '20. A high-performance anaerobic reactor 40 is shown, which contains internals 42 on which immobilized microorganisms colonize. The internals 42 can in particular be 470 special plate-like, porous structures with a mutual spacing, which are positioned in the reactor 40 as an overall cuboid-shaped package. When starting up, microorganisms are introduced into the anaerobic reactor 40 which perform an anaerobic conversion of the homogenized, digested substrate mainly in CH ₄ , with a comparatively small proportion of 475 part of CO ₂ . This biogas is discharged from the top of the anaerobic reactor 40, see line 44.

In order to achieve a sufficiently long residence time (for example 8 to 24 hours) of the substrate in the reactor 40, liquid is continuously pumped out of the upper region of the 480 reactor 40 and recirculated below for entry into the reactor 40, see line 45. The finished process from the reactor 40, ie essentially the unreacted water from the substrate, e.g. recirculated to the first activation stage 6, see connection 46.

485 The two options described for the further treatment of the waste stream 30 from the reactor 20 can alternatively be practiced. However, it is also possible to practice the recirculation of part of the waste stream 30 to the first activation stage 6 in the same sewage treatment plant 2 and also to additionally install a high-performance anaerobic reactor 40,

490 which processes another part of the outflow 30.

It is emphasized that the recirculated outflow 30 and the water stream 46 do not necessarily have to be passed into the first activation stage 6. It is also possible to pass into the second activation stage 8 or partly into the first activation stage 495 6 and partly into the second activation stage 8.

Between the pre-treatment stage 4 and the first activation stage 6, a membrane filtration stage (not shown) can be provided to increase the impurity concentration of the waste water.

500

2 is intended to illustrate a sewage treatment plant 2 which works in accordance with the batch method in the aerobic treatment of the wastewater with bacteria. After pre-purification 4, as in the sewage treatment plant 2 according to FIG. 1, the waste water 22a enters a waste water basin 50. During a first time phase, biological clarification takes place with the formation of excess sludge, while the waste water contained in the basin 50, as further above for the wastewater treatment plant 2 described in FIG. 1, is ventilated from below. In a later time phase, clarification takes place without ventilation. Purified wastewater is drawn off close to the surface by means of a decanter 52, see stream 54. Excess sludge 56 is withdrawn from the bottom of the tank 50 from time to time and brought into the excess sludge storage 12. The jet collision reactor 20 is connected to the sludge reservoir 12. The recirculation of the waste stream 30 from the reactor 20 is recirculated into the lower area of the waste water in the basin 50. Alternatively or additionally, a high-performance anaerobic reactor 40 can be provided, as in the sewage treatment plant 2 in FIG. 1.

FIG. 3 shows the jet collision reactor 20, as is provided in the sewage treatment plant 2 according to FIG. 1 or according to FIG. 2, on a larger scale and in more detail. The pumps 26a and 26b set on the right and left are omitted for the sake of clarity. The reactor has a narrow feed channel 60a and 60b on the right and left. The feed channels 60a and 60b are also called nozzles. In the present example, they have a circular cross section and a diameter of 1.5 to 4 mm. Each of the feed channels 60a or 60b is provided in a plate-like insert 62a or 62b. The inserts 62a and 62b consist of very abrasion-resistant material, in the present example sapphire or hard metal. The axes of the two feed channels 60a and 60b are aligned with one another.

At the top of Fig. 3, the reactor 20 has an access port 64 for a gas stream. At the bottom of FIG. 3, the reactor 20 has an outlet opening 66 that is aligned with the access opening 64. The common longitudinal axis of the inlet opening 64 and outlet opening 66 intersects the common longitudinal axis of the feed channels 60a and 60b at right angles.

When the reactor 20 is operating, a jet of excess sludge 18 is radiated into the interior of the reactor 20 through the feed channels 60a and 60b. The two excess sludge jets meet at a collision point 68 halfway between the two feed channels 60a and 60b, the collision point 68 naturally having a certain volume expansion has, but overall is very small. The speed of the excess sludge jets depends on the diameter of the feed channels 60a and 60b, the pressure at which the excess sludge 18 is pressed through the feed channels 60a and 60b, and to a lesser extent on its consistency

545 onwards. The jet speed is very high; one can certainly work with jet velocities not far below the speed of sound, even with jet velocities above the speed of sound. At the collision point 68, where the two beams meet each other head on, the cell walls of the bacteria in the excess sludge 18 are largely destroyed. The

550 cell contents are released and homogenized. t The collision product is caused by the gas flow through the access opening

64 flows in, down through the outlet opening 66 as a homogenized, open substrate, distributed in the gas stream, discharged. The

555 gas flow discharge reliably avoids all deposits and blockages in the reactor 20. Even after the reactor 20 has been switched off, it does not have to be cleaned, because the shortly flowing gas stream automatically cleans the interior of the reactor 20. Transporting the substrate in the gas stream also has the advantage that during recirculation into the first loading

560 life level 6 an optimal (supplementary) air supply takes place there.

It is emphasized that the construction of the reactor 20 shown in FIG. 3 is not the only possible one. In particular, the alternative is also considered to "shoot" excess sludge jets from three feed channels at a common collision point.

The following technical data of a specific reactor 20 which can be used for the specific implementation of the invention are mentioned below:

- Two feed channels with a common longitudinal axis 570 - Two diaphragm pumps that can deliver 120 bar

- Diameter of the nozzles 1.5 to 4 mm

- Average working pressure during operation 70 to 120 bar

- Throughput of excess sludge through the reactor about 100 to 220 m ³ / day 575 - Electric drive power for each diaphragm pump 15 to 40 kW.

The wastewater treatment plant 2 shown in FIG. 4 is intended for wastewater which is highly contaminated with at least one organic waste. Such wastewater is produced in certain production plants and can only be handled with great difficulty, if at all, in 580 conventional sewage treatment plants.

After pre-cleaning 4, as in the sewage treatment plant 2 according to FIG. 1, the waste water 22a first reaches a storage basin 70. From there, the waste water is discharged

585 without, activation stage fed to a jet collision reactor 20 in the manner described above. The outflow stream 30 of the jet collision reactor 20 is, as described above, fed to a high-performance anaerobic reactor 40. The outlet 46 of the reactor is either a second area of the sewage treatment plant 2, having one or more activation

590 stages, supplied or merged with another wastewater stream and together with this z. B. finally cleaned in a municipal sewage treatment plant. The biogas generated in the reactor 40 leaves it via a line 44. The second area of the sewage treatment plant 2 or the municipal sewage treatment plant can be constructed like the sewage treatment plant 2 according to FIG. 1, but must

595 should not necessarily be constructed in this way.

Claims

600PATENTANSPRÜCHE

605 1. Process for the treatment of waste water, wherein an aerobic treatment of the waste water with microorganisms to form excess sludge is one of the stages of the treatment process, characterized in that

610 (a) that at least part of the excess sludge (18) is fed to a jet collision reactor (20) and discharged from it by means of a gas stream (28) as a homogenized, digested substrate;

(b) and that at least a majority of the substrate 615 - is either recirculated to the aerobic treatment of the waste water

- Or a high-performance anaerobic reactor (40) is fed to generate biogas

- Or partly recirculated 620 to the aerobic treatment of the waste water and partly fed to the high-performance anaerobic reactor (40) for the production of biogas.

2. Process for treating excess sludge from the treatment of waste water, 625 characterized in that the excess sludge to be treated

(18) fed to a jet collision reactor (20) and discharged from it by means of a gas stream (28) as a homogenized, digested substrate.

3. The method according to claim 1 or 2, characterized in that the gas stream (28) is an air stream, an oxygen-enriched air stream, an ozone stream or an air stream enriched with ozone.

635 4. The method according to any one of claims 1 to 3, characterized in that the excess sludge (18) to be treated is blasted into the jet collision reactor (20) at a pressure of 40 to 160 bar.

640 5. The method according to any one of claims 1 to 4, characterized in that the excess sludge (18) to be treated is first fed to a sludge storage tank (12) and is fed from the sludge storage tank (12) to the jet collision reactor (20).

645 6. The method according to any one of claims 1 to 5, characterized in that the excess sludge (18) to be treated comes partly from an activated sludge stage (6; 8) and partly from a secondary clarification stage (10).

650 7. The method according to any one of claims 1 to 6, characterized in that a considered partial volume of the excess sludge (18) to be treated is treated in several passes in succession through the jet collision reactor (20).

655 8. Process according to one of claims 1 to 7, characterized in that it is carried out as a batch process for at least some of the clarification stages, in which several stages of the clarification process take place in succession at a location under consideration.

660 9. The method according to any one of claims 1 to 8, characterized in that the wastewater is concentrated in a membrane filtration stage prior to aerobic treatment.

10. Wastewater treatment plant, which has a basin (6; 8) in which an aerobic 665 treatment of wastewater (22) with microorganisms to form

Excess sludge (18) can be carried out, characterized in that

(a) that a jet collision reactor (20) with gas flow discharge (18) of the 670 collision product is provided, the jet collision reactor

(20) is connected to the aerobic treatment basin (6; 8) for transferring at least part of the excess sludge (18);

(b) and that for at least a majority of the collision product stream 675 (30)

- The jet collision reactor (20) is connected to the aerobic treatment basin (6; 8) for recirculation

- And / or the jet collision reactor (20) is connected to a high-performance anaerobic reactor (40) for the production of biogas.

680

11. Wastewater treatment plant according to claim 10, characterized in that for the gas stream discharge (28) is an air stream, an oxygen-enriched air stream, an ozone stream or an air stream enriched with ozone.

685

12. Wastewater treatment plant according to claim 10 or 11, characterized in that the jet collision reactor (20) is designed with a pressure of 40 to 160 bar for jet generation.

690 13. Wastewater treatment plant according to one of claims 10 to 12, characterized in that the jet collision reactor (20) is equipped with nozzles (60a, 60b) for jet generation which have a diameter of 1 to 5 mm.

695

14. Wastewater treatment plant according to one of claims 10 to 13, characterized in that the jet collision reactor (20) at least 700 a membrane pump (26a; 26b) for generating the pressure for the

Beam generation is assigned.

15. Wastewater treatment plant according to one of claims 10 to 14, characterized in that the jet collision reactor (20) per jet 705 nozzle (60a, 60b) is assigned its own pump (26a, 26b).

16. Wastewater treatment plant according to one of claims 10 to 15, characterized in that the jet collision reactor (20) is designed for multiple runs of a sub-volume of the excess sludge (18) to be treated (18) to be treated.

17. Wastewater treatment plant according to one of claims 10 to 16, characterized in that between the aerobic treatment basin (6; 8) and the jet collision reactor (20), a sludge reservoir (12) is interposed.

18. Wastewater treatment plant according to one of claims 10 to 17, characterized in that a secondary clarifier (10) is provided, the jet collision reactor (20) also being connected to the secondary clarifier (10) for 720 transfer of at least some of the excess sludge (18) is.

19. Wastewater treatment plant according to one of claims 10 to 18, characterized in that it is designed as a batch plant for at least some of the clarification stages 725, in which several treatment stages take place in succession at a location under consideration.

20. Wastewater treatment plant according to one of claims 10 to 19, characterized in that a membrane filtration stage for concentrating the wastewater is provided in front of the aerobic treatment pool (6; 8) 730.

21. Wastewater treatment plant according to one of claims 10 to 20, characterized in that the high-performance anaerobic reactor (40) contains 735 internals (42) for immobilizing microorganisms.

22. jet collision reactor (20) with gas flow discharge of the collision product, characterized in that it is designed and intended for treating excess sludge (18) from the clarification of waste water.

740

23. jet collision reactor (20) according to claim 22, characterized in that for the gas stream discharge (28) is an air stream, an oxygen-enriched air stream, an ozone stream or an air stream enriched with ozone.

745

24. jet collision reactor (20) according to claim 22 or 23, characterized in that it is designed with a pressure of 40 to 160 bar for jet generation.

750 25. Jet collision reactor (20) according to one of claims 22 to 24, characterized in that it is equipped with nozzles (60a, 60b) for jet generation which have a diameter of 1 to 5 mm.

26. jet collision reactor (20) according to one of claims 22 to 25,

755 • characterized in that it is assigned at least one diaphragm pump (26a, 26b) for generating the pressure for generating the jet.

27. Jet collision reactor (20) according to one of claims 22 to 26, characterized in that it has its own per jet nozzle (60a, 60b)

760 pump (26a, 26b) is assigned.

28. Jet collision reactor (20) according to one of claims 22 to 27, characterized in that it is designed for multiple throughputs of a sub-volume of the excess sludge (18) to be treated

765 is.