WO2008098725A1 - Process and device for treating sewage sludge, wastewater or a suspension of particulate substances - Google Patents

Abstract

The present invention relates to a process and a device for treating sewage sludge, wastewater and suspensions of particulate substances and also use thereof for avoiding or reducing the formation of bulking sludge, floating sludge and/or foam in clarified sludge, wastewater or a suspension of particulate substances. The device according to the invention consists of a homogenizer, a disintegration device and a comminutor for treating sewage sludge, wastewater or suspensions of particulate substances.

Description

 Description:

Method and device for treating sewage sludge, waste water or a suspension of particulate substances

Technical area:

The present invention is in the field of wastewater treatment in industrial or municipal sewage treatment plants.

State of the art:

Biological wastewater treatment in industrial or municipal wastewater treatment plants usually involves the activated sludge process (also known as "activation process"). In the activated sludge process, the wastewater is purified from organic contaminants by the metabolic activity of aerobic microorganisms contained in the biomass. The biomass is a mixed biocoenosis of various types of microorganisms, the majority of which are flocculating bacteria and filamentous bacteria. In the activated sludge process, the biomass is usually separated from the treated wastewater by sedimentation in a secondary settling tank or sedimentation tank, withdrawn from the bottom of the tank and partly fed as return sludge into the activated sludge tank and partly as excess sludge for digestion.

For the biological metabolization of organic substances by the microorganisms contained in the sewage sludge, a sufficient ventilation of the waste water-activated sludge mixture with oxygen is required. This is usually done by aerators, with the help of compressed air or pure oxygen is introduced into the wastewater mixture. The oxygen is needed for the oxidation of hydrocarbon compounds and ammonium. For example, the oxygen (O ₂ ) is necessary in order to oxidize the ammonia (NH ₄ ) which has a toxic effect on some bacteria via the intermediate nitrite (NO ₂ ) to nitrate (NO ₃ ). This process is also called nitrification and requires the necessary bacteria (nitrifying agents) and a sufficient amount of dissolved oxygen. As a result, optimal supply of oxygen must be ensured for the stable operation of a wastewater treatment plant. The so-called chemical oxygen demand (COD) is used to measure the oxygen required for the metabolisation of organic substances. This gives information about the efficiency and stability of a sewage treatment plant in the activated sludge process. In addition to adequate ventilation, the average residence time of the bacterial sludge in wastewater treatment plants, which is also referred to as sludge age, must also be taken into account. Over the age of sludge it can be ensured that the residence time of the microorganisms in the settling tank is long enough that also slowly growing bacteria with a longer generation time have time for the growth. These include in particular bacteria that are responsible for the metabolism of nitrification. The sludge age depends on the amount of sludge in the system and the daily sludge surplus due to the increase in biomass. In addition to nitrification, other processes, such as denitifration (reduction of nitrate to molecular nitrogen) or the removal of phosphate in the activated sludge process, are discontinued.

In the activated sludge process - as already mentioned above - the separation of the biomass in the secondary clarifier is an essential part. Due to the present in biomass Mischbiozönose of flocculating bacteria and filamentous microorganisms, the ratio of these types of bacteria in activated sludge for the sedimentation of biomass is of considerable importance. One problem with wastewater treatment and treatment plants is the formation of undesirable bulking sludges and scum that results from increased growth of filamentous bacteria. The filamentous bacteria have the property of aggregating into larger aggregates, thereby significantly hindering the above-described thickening and sedimentation process of the activated sludge. This has the consequence that a large biomass loss from the secondary sedimentation tank (so-called sludge output) occurs and the biomass content in the system decreases. As a result, the cleaning performance of the wastewater treatment plant or wastewater treatment plant can also be reduced.

In addition to the bulking sludge caused by filamentous microorganisms, scum formation also has a detrimental effect on the operation of sewage treatment plants or sewage treatment plants. Floating sludge is produced in particular by denitrification and development of bacteria with lipophilic surfaces.

In order to prevent or at least reduce the formation of bulking sludge and floating sludge in sewage treatment plants, various processes are known in the prior art to influence the mixed biocoenosis in the biomass of the activated sludge in favor of flocculating bacteria and to avoid the formation of aggregates of filamentous bacteria.

From DE 195 17 381 and DE 198 43 862 methods are known in which

Sewage sludge in sewage treatment plants is treated with ultrasound. Ultrasonic treatment also destroys cellular structures of the microorganisms to a certain extent. However, ultrasound sonotrodes are very expensive and consume a large amount electrical energy. Furthermore, the digestion of the microorganisms and the homogeneity of the sludge decomposition is unsatisfactory.

In the magazine "Water / Wastewater Practice" (WRP) No. 3, 1999, pages 25 to 31, a mechanical comminution of swelling and floating slurries using a stirred ball mill, a shear gap, an ultrasonic or a high-pressure homogenizer is proposed. However, these methods do not result in the desired level of disintegration, i. Cell disruption of microorganisms.

WO 03/042109, US Pat. No. 6,200,486 and US Pat. No. 6,505,648 describe a method and a device for treating aqueous suspensions of organic substances or sewage sludge by utilizing cavitation forces.

Cavitation is the local formation and dissolution of bubbles or voids in liquids due to pressure fluctuations. The cavitation bubbles are created by lowering the static pressure below the vapor pressure of the liquid, forming individual vapor or gas bubbles. According to the law of Bernoulli, the higher the velocity, the lower the pressure in a liquid. With increasing flow velocity of the liquid, there is a further pressure reduction. The gases dissolved in the liquid diffuse into the resulting bubbles or cavities. When the pressure in the liquid increases again, the vapor in the bubbles or cavities condenses and the gas bubbles collapse abruptly due to the external pressure. This results in very high local pressure and temperature peaks. Furthermore, the gas in the bladder is ionized and generates radicals that may be chemically reactive. Furthermore, the collapse of the bubble creates extreme local shock and pressure waves which result in a flow of fluid through the negative pressure of the collapsed bubble. These fluid streams are often referred to as "microjets" or "liquid jets".

In the processes disclosed in the above patents, the suspension is conveyed under pressure through a nozzle having an initially narrowing and then widening cross-section. By reducing the cross-section, the flow rate of the suspension is increased so much that the pressure of the liquid (typically water) falls below the vapor pressure, causing the formation of local gas-filled cavitation bubbles. In the subsequently widening cross-section of the nozzle, it comes as a result of the sudden decrease in the

Flow rate to a pressure increase and collapse of cavitation bubbles. However, the cavitation processes described in the prior art have drastic disadvantages. On the one hand, material damage can occur, since the rapid formation and dissolution of cavitation bubbles and the associated pressure and temperature peaks can cause abrasions on the surface of the nozzle. Although the shock waves and jets emanating from the bubbles have the power to

Dissolve particle agglomerates. On the other hand, the collapse of the bubbles leads to considerable material wear being observed in the area of surfaces. In other areas where cavitation phenomena occur, e.g. In the case of a ship's propeller, this effect is called "cavitation", where the surface material is slowly leached out by the high mechanical stresses, and after some time, even larger components can break out of the surface until the material becomes unusable The use of cavities to clean up soiled objects, for example using ultrasonic baths, has a positive advantage, but such material removal is undesirable for the hydrodynamic disintegration of sewage sludge.

In order to counteract the disadvantages of cavitation such as material removal or insufficient digestion by only locally occurring cavitation bubbles, WO 2005/028375 has proposed a method and a device for comminuting particulate organic substances in suspensions of microorganisms, in which the formation of cavitation bubbles is avoided by the flow rate of the carrier medium (ie the (sewage sludge) suspension) is so high through a reaction space having a constriction that the carrier medium almost completely changes from its liquid phase to a homogeneous vapor phase. Usually, for this purpose, the suspension to be treated is carried out through a nozzle which has a larger diameter in its inlet area and in its outlet area than the cross section in the central narrowing area. As a result, the microorganisms or particle agglomerates contained in the suspension are subjected to a brief extreme acceleration and, if the vapor phase in the outlet region condenses back into the liquid phase, then exposed to an extreme delay. By acting on these microorganisms and particle agglomerates

Acceleration and deceleration forces will eventually produce the desired effects, e.g. Cell disruption and cavitation-free disintegration achieved while avoiding the locally occurring unwanted cavitation phenomena with the disadvantages described above.

Although the methods described above, when applied to sewage sludge, lead to a reduction in bulking sludge, scum and / or foam, and the proportion of filamentous bacteria to floc-forming bacteria decreases Degree of disintegration and the biological activity of the disintegrated sewage sludge can still be increased.

It is therefore an object of the present invention to significantly increase the biological activity of the disintegrated sewage sludge and thus the efficiency of wastewater treatment plants.

To measure the biological activity of the digested sewage sludge in the activation process usually the chemical oxygen demand (COD value) is used. The COD value is a measure of the sum of all substances present in the water that can be oxidized under certain conditions. It therefore indicates the amount of oxygen that would be required for the oxidation of these substances, if oxygen would be used as a pure oxidant. Since a biological wastewater treatment plant with a proper function mainly dissolved, non-biodegradable organic substances in sewage sludge or wastewater are included and to a lesser extent biotically degradable organic matter and particulate organic matter, the COD value can be used to the streams of organic Describe carbon compounds in wastewater treatment plants. It is desirable to obtain the best possible reaction kinetics of the activated sludge process, for example, to assess the proportion of non-biodegradable organic substances, the oxygen demand in the activated sludge tank or the biological activity of the return sludge.

It is therefore in view of the known state of the art object of the present invention to provide a process with which the biological activity of digested sewage sludge, sewage or other suspensions becomes more particulate

Substances in wastewater treatment plants compared to the methods known in the art is increased.

This object is achieved by a method and a device according to claim 1 and claim 13.

Summary of the invention:

The process according to the invention for treating sewage sludge, wastewater or a suspension of particulate substances comprises:

a) mechanical comminution of the coarse constituents contained in the sewage sludge, waste water or the suspension of particulate substances, b) homogenizing the sewage sludge, wastewater or the suspension of particulate substances treated in step a),

c) disintegrating the homogenized sewage sludge, waste water or the suspension of particulate substances into a reaction space, which has a convergent

Channel part and a constriction, wherein upon entry into the active space, a vapor stream is generated, which exerts a short-term extreme acceleration on the substances contained in the support medium and condenses on leaving the active space back into the liquid phase, thereby causing extreme deceleration forces,

d) supplying the disintegrated sewage sludge, waste water or the suspension of particulate substances in a reaction phase for a certain period of time, so that an increase in the biological activity of the disintegrated sewage sludge, sewage or the suspension of particulate substances and its components is achieved.

The device according to the invention for the treatment of sewage sludge, waste water or suspensions of particulate substances comprises:

a homogenizer with means for comminuting in the sewage sludge,

Wastewater or the suspension of particulate substances contained coarse ingredients, a disintegration device with a reaction space comprising a convergent channel portion and a constriction, wherein upon entry into the active space, a vapor stream is generated, which exerts a short-term extreme acceleration on the substances contained in the carrier medium and which condenses back into the liquid phase upon leaving the reaction space and thereby causes extreme deceleration forces, a contaminator with means for mixing or circulating the disintegrated sewage sludge originating from the disintegration device,

Waste water or the suspension of particulate substances.

The device is suitable for preventing or reducing the formation of bulking sludge, floating sludge and / or foam in sewage sludge, waste water or a suspension of particulate substances. The device can also be used to influence the Mischbiozönose in sewage sludge, wastewater or suspension of particulate substances, in which there is a decrease of filamentous microorganisms in favor of flocculating microorganisms in the sewage sludge, sewage or the suspension of particulate substances. Description of the invention:

The process according to the invention for the treatment of sewage sludge, waste water or a suspension of particulate substances comprises a four-stage process in which, in a first step, a mechanical comminution of the coarse constituents contained in the sewage sludge, the wastewater or the suspension of particulate substances takes place. This is done in a crushing device in which a suitable cutting unit is arranged. After comminution in a second step, a homogenization of the comminuted mixture in a homogenizer. In the homogenizer is a circulation plant, with which a circulation of the sludge mass takes place. Preferably, the circulating system is a mixing axis extending transversely to the direction of flow and having mixing paddles mounted thereon. The comminution and homogenization step ensures that no fluid-mechanical blockages occur in the subsequent disintegration step and all components of the sludge can be exposed to the disintegration step on an equal basis. Furthermore, an increase in the degree of disintegration can already be seen in the comminution and homogenization of the sewage sludge, which is reflected in an increase in the COD value (see FIG. 1). In one embodiment, the comminution and homogenization are part of a one-step process.

Prior to the homogenization step, a thickening of the sewage sludge, wastewater or the suspension of particulate substances usually takes place. Preferably, a thickening is aimed at starting from a dry matter value TS = 0.6% to a dry matter value TS = 6%. A thickening TS of about 6% is particularly preferred.

In the subsequent third step of the process according to the invention, the actual disintegration step, the homogenized sewage sludge is fed to a disintegration device having a reaction space in which the liquid carrier medium of the sewage sludge, usually water, is subjected to a short-term extreme acceleration, whereby the vapor pressure of the carrier medium relative to the pressure in the Effective space is greatly lowered and the carrier medium is completely transferred from its liquid phase in the vapor phase. As a result, a homogeneous vapor stream is generated, which briefly exerts an extreme acceleration when entering the reaction space on the sludge particles and releases extreme deceleration forces when leaving the reaction space when the vapor phase condenses back into the liquid phase. For this purpose, at the end of the convergent duct part, a flow velocity must be achieved which is greater than the critical velocity for a phase change (liquid vapor) and which is characterized solely by the density of the water and the atmospheric pressure. In the limiting case, ie when the flow velocity of Corresponds to critical speed, formed in the narrowest channel cross-section, a discontinuity surface over which the phase change of water into water vapor takes place.

The effective space essentially consists of a channel having a central constriction, which has a larger diameter in its inlet and outlet area than the central channel part with its constriction. Preferably, the reaction space comprises a convergent channel part with a narrowest channel cross-section.

In one embodiment, the active space is a nozzle. Usually, the diameter (d) and the length (I) of the nozzle are in a ratio of 1: 4 to 1: 6, preferably in a ratio of 1: 5 to each other. According to the invention, the flow velocity in the inlet region of the reaction space is increased so much that the carrier medium of the treated suspension in the reaction space completely passes from the liquid phase to the vapor phase (i.e., to water vapor) and no cavitation bubbles are formed. When leaving the reaction space, the steam flow is due to the increasing diameter in the

Exhaust region exposed strong deceleration forces and there is a condensation of water vapor.

In order to avoid the cavitation phenomena mentioned, a flow velocity (u) of at least 28 m / s, preferably at least 42 m / s, preferably at least 50 m / s, is achieved in the reaction space (m / s = meter per second). A

Flow rate in a range of 42 m / s to 50 m / s is particularly preferred for the treatment of sewage sludge and has proven to be advantageous. The transition to the vapor phase takes place at a critical speed u _krιt . At the critical velocity, the formation of cavitation bubbles, which lead to the unwanted local effects, is largely avoided. Furthermore, at this speed an influencing of the membrane surfaces of the microorganisms with release of surface-active substances (eg integral membrane proteins) and a dissolution of aggregates of filamentous bacteria takes place. Cellular breakdowns are also observed with the associated release of the cytoplasm and the biologically active substances dissolved therein

Substances and enzymes. The release of biologically active substances from the cell interior or in the cell membrane-bound proteins leads to increased biological activation of the metabolic processes in the sewage sludge already after disintegration, which is reflected in an increase in the COD value.

After disintegration, the disintegrated sewage sludge, wastewater or suspension of particulate matter (in short: the disintegrated mixture) are exposed in a fourth step to a reaction phase in a contaminant which allows the disintegrated mixture to act chemically and biologically. This will be the Mixture, optionally with agitation or stirring for a certain period of time collected in a reaction vessel and derived for further use. Both continuous operation and batch operation are possible.

Although the exact conditions and processes in the contaminant are not fully understood, the inventors have found that due to the reaction phase, chemical and biochemical processes occur which lead to a dramatic increase in the COD value and thus the biological activity of disintegrated sewage sludge. It is believed that enzymatic and chemical reactions take place in this phase, ultimately responsible for the significant increase in COD. Furthermore, it is conceivable that proteolytic enzymes are involved in the further disintegration of microorganisms. In other words, microorganisms that have not been completely digested in the disintegration step are digested by released digestive enzymes (e.g., proteases, lipases, nucleases, phosphatases, etc.) and the active cell contents are released.

As a result of the reaction step taking place in the contaminant, the increase in the COD value already determined after the disintegration is again drastically increased (see FIG. 1). This results in a higher performance and operational stability of the wastewater treatment plant. Due to the higher oxygen content, the chemical reactions described for the activated sludge process ultimately run off faster and more efficiently. By virtue of the fourth reaction step according to the invention, the COD value is increased by at least 200%, in contrast to the three-stage process known from the prior art (without the fourth reaction step). Increases in the COD values of up to 400% or more can be achieved compared to the conventional three-stage process. in the

Cut, the COD increase in the four-stage process is in the range of 200% to 500%. To further increase the COD and carbon yield, the disintegrated mixture from the disintegration step is preferably recirculated. This is achieved for example with a stirrer with vertical and / or horizontal stirring plates. By stirring the disintegrated sewage sludge additionally experiences an extreme increase in efficiency.

According to the invention, the process according to the invention mainly treat wastewater or sewage sludge (such as return sludge, excess sludge). However, the method (as well as the apparatus described below) can also be used for other (aqueous) suspensions which contain particulate substances or particle agglomerates. The suspensions may be a mixture in which microorganisms are contained and cell disruption is desired. For conveying the suspension to be treated by the method according to the invention, the device contains a pump whose power consumption is sufficiently high so that the high flow velocities of at least 28 m / s required for cavitation-free disintegration are achieved in the reaction space.

The invention further relates to a device or a plant for carrying out the method described above. The device comprises

a crusher with means for crushing the coarse contained in the sewage sludge, sewage or the suspension of particulate substances

Ingredients, a homogenizer with means for homogenizing the sewage sludge, the waste water or the suspension of particulate substances, a disintegration device with a closed reaction space, in which the liquid carrier medium of sewage sludge, sewage or the suspension of particulate substances is exposed to a short-term extreme acceleration on entering the reaction space whereby the carrier medium is converted from its liquid phase into a homogeneous vapor phase, so that the substances contained in the carrier medium are subjected to a brief extreme acceleration, which subsequently passes through the effluent space upon exiting from the reaction space

Condensation of the vapor phase in the liquid phase are exposed to extreme retarding forces, a contaminant with means for circulating the out of the

Desintegrationsvorrichtung derived disintegrated sewage sludge, sewage or the suspension of particulate substances.

The crusher takes over the first, the homogenizer the second, the disintegration device the third and the contaminator the fourth process step of the method according to the invention.

Preferably, the device or plant is a wastewater treatment plant.

Preferably, the shredder is a conventional shredder, such as a rotary blade cutter, a knife mill, a shredder or a mill cutter, which breaks down the larger components into small components by attrition, grinding, shredding or cutting. The homogenizer uses a mixer. Usually, it is a continuous mixer in which one or more mixing paddles are arranged on a mixing shaft in the flow channel. Such mixers typically operate at 1400 to 2800 revolutions per minute. However, other methods of homogenization are conceivable, such as the use of ultrasound, centrifugal forces or shear forces.

In one embodiment, the device according to the invention contains means with which it is possible to bring non-disintegrated sewage sludge (or a suspension of particulate substances) into contact with disintegrated sewage sludge (or a suspension of particulate substances). Such means include, for example, wiring systems, pumping systems or collection vessels. For possibly repeated return of the sludge to the disintegration device means are provided, with which a return of the sewage sludge can be carried out in the disintegration device. Such means include, for example, piping systems having the proper diameters and pumping circuits.

The effective space of the disintegration device consists of a constriction in which the diameter at the entry point of the active space and at the exit point of the active space is greater than the inner diameter at the constriction. Preferably, the reaction space is a nozzle. The geometric conditions required for the effective space are preferably achieved when the diameter (d) and the length (I) of the nozzle are in a ratio of 1: 4 to 1: 6, preferably in a ratio of 1: 5 to each other. The flow velocity u in the reaction space required for the vapor phase transition is at least about 28 m / s, preferably at least about 42 m / s and more preferably at least about 50 m / s, with speeds in the range from about 42 m / s to 50 m / s have turned out to be optimal.

The contaminator contains an agitator with vertical and / or horizontal agitator plates for circulating the disintegrated sludge mixture.

When using the method according to the invention or when using the device according to the invention, a significant reduction or avoidance of the formation of bulking sludge, scum and / or foam in wastewater treatment is found. Furthermore, the mixed biocoenosis in the sewage sludge is positively influenced, which is reflected in a decrease of filamentous bacteria in favor of flocculating microorganisms. The additional reaction step in the method according to the invention can be a significant modification of some parameters that can be used to assess the performance and stability of a wastewater treatment plant, for example: increase in denitrification, increase in chemical oxygen demand (COD), increase in biochemical oxygen demand (BOD), decrease in power consumption (P _tot ) _/ decrease in sludge volume index (ISV), decrease in oxygen concentration in the aeration tank.

Brief description of the drawings:

The invention will be explained in more detail in the following drawings. Show it

1 is a schematic representation of the four-stage process with crushing, homogenization, disintegration, contamination to achieve an intense biological activation with low power consumption,

2 is a schematic representation of an active space of the disintegration device,

3 is a photographic representation of the vapor stream generated in the reaction space,

4 shows a comparison of the biological activation with and without additional reaction step after the disintegration step.

Ways to carry out the invention and commercial usability:

FIG. 1 shows the power expenditure (P _x ) and the increase in biological activation (COD ₁ ) in the individual phases (stages 1-4) of the method according to the invention. In the crusher, the sludge to be disintegrated is first mechanically comminuted and homogenized in the homogenizer to form a homogeneous mass for the subsequent disintegration device. These two steps upstream of the disintegration ensure that no fluid-mechanical blockages occur during disintegration and that the constituents of the sewage sludge can be exposed to the disintegration process on an equal footing. It can be seen that mechanical disruption (stage 1) and the subsequent homogenization (stage 2) and the associated mechanical shear forces are already used to break up part of the microorganisms, resulting in a slight increase in the COD value (CSBi and COD ₂ ). compared to the initial value (CSB ₀ ) makes noticeable.

The following disintegration device is essentially a hydrodynamic one

Device for generating a time-average effective space (see Fig. 3), in which the sewage sludge undergoes a treatment that leads to a significant biological activation, which is recognizable by the increase of the COD value. In the contaminant, the disintegrated sewage sludge originating from the disintegration device is subjected to a reaction time. This is preferably done by circulating the sewage sludge, so that the active ingredients such as enzymes and the living microorganisms contact each other and metabolic processes can proceed. In this, the disintegration downstream phase shows a drastic increase in the COD value of up to 500%. The observed increase in the COD value depends on the biological activation achieved with the disintegration device, the size of the disintegrated mass flow and the residence time in the contaminant. In the case of a disintegrated mass flow m _Des > m _{des kril} , a significant COD increase can be _detected in the contaminant, which clearly exceeds the COD increase by the disintegration device itself. The COD value can be increased even further by passing the mixture through the disintegration device several times. The bringing into contact of the sewage sludge is preferably carried out with a stirrer with low power consumption.

One recognizes from these data that the COD value is combined by the four-stage

Process, in particular by the disintegration downstream fourth reaction step, can be dramatically increased. Furthermore, the occurrence of swelling and floating sludge is avoided or reduced, and there is no need for external carbon sources (C donors) to stabilize the denitrification of the plant (data not shown).

In Fig. 2 above can be seen the effective space shown schematically. If the flow velocity (u) _exceeds the critical flow velocity (u> u _kπt ) for a _{span of active} space with a length l _w > 0, a transition of the liquid phase into the vapor phase occurs. In the sketch below, a discontinuity _{surface is} shown as a limiting case with u = u _kπt .

To generate the effective space, the sewage sludge flowing through the convergent duct part (dA / dx <0, duct cross-section A (x)) is put into a state which causes the water surrounding the microorganisms to evaporate. For this purpose, at the end of the convergent channel part, a velocity u-≥ U _{kπt must be} reached, which is characterized solely by the density of the water and the atmospheric pressure. In the limiting case u = u _kπt , a discontinuous _surface forms in the narrowest channel cross-section, via which the phase change from water to water vapor takes place. In this special case, the length l _w = 0 does not yet have a finite effective space. A usable effective space is only _clamped at speeds u> u _knt . The length of the effective space l _w > 0 can also be determined by the choice of the cross-sectional distribution A (x) of the divergent following the narrowest point

Channel part (dA / dx> 0) are affected and ends when the critical velocity u _kπ t is reached again in the divergent channel part. As a result of the phase change (water evaporates to water vapor), the microorganisms leap abruptly into a flow field with speeds increased by a factor of 1000 as they enter the active reaction space, which then jump sharply as they leave the effective space by precisely this increase. By increasing the speed to values, effects can be achieved _ranging from the detachment of bioactive substances on the surface of the microorganisms to the disruption of the microorganisms and the release of the cell constituents by cell disruption. The effects are essentially caused by the mass forces acting on the organic components of the sewage sludge when passing through the active active space. By selecting the velocity u> u _{krιt of} the sewage sludge, which leads in the narrowest channel cross-section just on the vapor pressure of the water, a selective selection of the microorganisms can be made.

The process of permanently built up and degraded in the effective space with a state of aggregate largest surface leads in sewage sludge with conventional TS levels on hydrodynamically independently generated high-frequency pressure peaks in the range of (10 to 20) kHz, the acoustically by the resulting intense bang be perceived. The popping noises start when the critical speed is reached u = u _kπt and increase simultaneously with the increase of the speed to values u> u _krιt .

In contrast to common cavitation effects, whose local behavior is associated with destructive material, homogeneous microcavitation _{occurs in the effective space} generated at high velocities u> u _kπt , which excludes abrasion and destruction of the channel walls.

In Fig. 3 can be seen an existing vapor steam jet in the effective space of a disintegration device, which was made visible by means of a photographic image. Reaches the flow velocity u, the critical velocity u _KNT and the evaporation pressure of the liquid is reached, a phase transition, whereby the particulate matter (especially microorganisms) present in the carrier media are subjected to a short-term extreme acceleration. At the end of the effective space increases its diameter, whereby the vapor stream is greatly delayed and condensed immediately. Due to these strong forces, the microorganisms and particle agglomerates are finally digested. Digestion by local cavitation effects (cavitation bubbles) would not lead to the observed result.

FIG. 4 shows a comparison of the COD increase with and without a subsequent reaction step (contamination). It can be clearly seen that with the additional reaction step, the increase in the chemical oxygen demand (COD value) can be significantly increased. Shown is the ratio CSB ₄ to CSB ₃ (ordinate) against time (abscissa). From one For a certain period of time, there is no further increase in the CS B value. As a result, the process according to the invention has an advantage over a process operated without this additional reaction step. Furthermore, the plants operated by utilizing the local cavitation and the disadvantages occurring there are avoided.

Further measurements have shown (not shown) that the method according to the invention or the device with the described disintegration leads to a positive influence on the following parameters in a significant way: reduction of the N _ges cutoff values, COD increase, BOD increase, reduction of the Power requirement (P _ges ) _/ decrease in sludge volume index (ISV, reduction by approx. 25%), reduction in dry matter content (TS content: reduction in activation by 50% from 4 g / l to 2 g / l), reduction in sludge volume O ₂ concentration in the aeration tank (reduction from 2.7 mg / l to 0.95 mg / l). At the same time, a reduced oxygen requirement is determined by the partial omission of endogenous respiration, which can save considerable costs.

Furthermore, a significant destruction of thread-like flake / organism structures as well as a drastic decrease or avoidance of swelling and floating sludge are observed. The increased COD value also causes an increase in the decomposition of organic substances and improved denitrification by the provision of easily degradable COD as a hydrogen donor. This is one

Optimization of aerobic and anaerobic degradation possible. The anaerobic digestion (digestion) is reflected in a higher degree of digestion with shorter digestion times, a higher gas yield, a better stabilization result and an optimization of the sludge dewatering behavior. During aerobic degradation (activation), stabilization of the biocenosis is observed. There is a reduction or elimination of the temporary occurrence of swelling and floating sludge in the aeration tank. Overall, there is an improved aerobic pollutant degradation by the improved biological activation in the inventive method and apparatus.

In summary, the costs and the efficiency of the wastewater treatment process and the sludge treatment can be drastically reduced using the method according to the invention or the device according to the invention. This not only applies to the ongoing clarification processes, but also to all costs and material expenses incurred for the operation of the plant.

Although the device according to the invention is preferably designed as part of a sewage treatment plant for the cavitation-free disintegration of sewage sludge, also other applications of the combined disintegration below Use of the four-step process conceivable, such as the degradation of particle agglomerates or the digestion of microorganisms in aqueous suspensions.

Claims

Claims: A process for the treatment of sewage sludge, waste water or a suspension of particulate substances, comprising: a) mechanical comminution of the coarse constituents contained in the sewage sludge, waste water or the suspension of particulate substances, b) homogenizing the sewage sludge, wastewater or the suspension of particulate substances treated in step a), c) disintegrating the homogenized sewage sludge, waste water or the suspension of particulate substances in a reaction space comprising a convergent channel portion and a constriction, wherein upon entering the reaction space, a vapor stream is generated which exerts a short-term extreme acceleration on the substances contained in the support medium and condenses back into the liquid phase when leaving the active space and thereby causes extreme deceleration forces, d) supplying the disintegrated sewage sludge, waste water or the suspension of particulate substances in a reaction phase for a certain period of time, so that an increase in the biological activity of the disintegrated sewage sludge, sewage or the suspension of particulate substances and its components is achieved. 2. The method according to claim 1, characterized in that the comminution in step a) and the homogenization in step b) are carried out in one stage. 3. The method according to claim 2, characterized in that the individual process steps a) to d) take place in spatially separate but mutually communicating areas. 4. The method according to any one of claims 1 to 3, characterized in that the change in the flow velocity via a conically extending constriction of the active space, wherein the diameter at the entry point of Wirkraumes and the diameter at the exit point of the active space is greater than the diameter at the narrowest point of the constriction. 5. The method according to claim 4, characterized in that it is the conical constriction is a nozzle. 6. The method according to claim 5, characterized in that the diameter (d) and the length (I) of the nozzle in a ratio of 1: 4 to 1: 6, preferably 1: 5, to each other. 7. The method according to any one of claims 1 to 6, characterized in that the flow velocity u in the active space at least 28 m / s, preferably at least 40 m / s, preferably between 42 m / s and 50 m / s. 8. The method according to any one of claims 1 to 7, characterized in that the residence time for the disintegrated sewage sludge, the waste water or the suspension of particulate substances in the reaction step c) is at least as long that the chemical oxygen demand (COD value) over the Initial value before the Disintegration is increased by at least 200%. 9. The method according to any one of claims 1 to 8, characterized in that the sewage sludge, the waste water or the suspension of particulate substances in the reaction step c) is mixed or circulated. 10. The method according to any one of claims 1 to 9, characterized in that at least part of the treated in the reaction step c) sewage sludge, sewage or the suspension of particulate substances is recycled to the disintegration step b). 11. The method according to any one of claims 1 to 10, characterized in that it is the sludge to return sludge and / or excess sludge. 12. The method according to any one of claims 1 to 11, characterized in that in the Contaminator in the reaction step c) is fed to non-disintegrated sewage sludge, waste water or suspension of particulate substances, which is brought into contact with already disintegrated sewage sludge, sewage or suspension of particulate substances for infection. 13. Apparatus for treating sewage sludge, waste water or suspensions of particulate substances, comprising: a homogenizer with means for comminuting coarse constituents contained in the sewage sludge, waste water or the suspension of particulate substances, a disintegration device with a reaction space comprising a convergent duct part and a constriction, wherein when entering the Wirkraum a vapor stream is generated, which exerts a short-term extreme acceleration on the substances contained in the support medium and condenses on leaving the active space back into the liquid phase, thereby causing extreme deceleration forces - a contaminant with means for mixing or circulating of the Desintegrationsvorrichtung derived disintegrated sewage sludge, sewage or the suspension of particulate substances. 14. The apparatus according to claim 13, characterized in that the diameter at the entry point of the active space and the diameter at the exit point of the Wirkraumes is greater than the inner diameter at the constriction. 15. Device according to claim 14, characterized in that the constriction is a nozzle. 16. The apparatus according to claim 15, characterized in that the diameter (d) and the length (I) of the nozzle in a ratio of 1: 4 to 1: 6, preferably 1: 5, to each other. 17. Device according to one of claims 13 to 16, characterized in that the Flow velocity u in the reaction space is at least 28 m / s, preferably at least 40 m / s, preferably between 42 m / s and 50 m / s. 18. Device according to one of claims 13 to 17, characterized in that the device comprises means, such as wiring systems and pumping systems, not disintegrated sewage sludge, wastewater or suspension of particulate substances with disintegrated sewage sludge, sewage or suspension of particulate substances in the contaminant in contact bring to. 19. Device according to one of claims 13 to 18, characterized in that the Apparatus comprises means, such as conduit systems and pump systems, with which there is a recycling of sewage sludge, waste water or suspension of particulate substances from the contaminant in the disintegration device. 20. Device according to one of claims 13 to 19, characterized in that the contaminant contains an agitator with vertical and / or horizontal Rührtellern. 21. Device according to one of claims 13 to 20, characterized in that the device further comprises a pump with which the sewage sludge, the waste water or the suspension of particulate substances through the disintegration device with the above the critical speed (u _krιt ) lying required flow rate (u) is promoted (u> u _kπt ). 22. Device according to one of claims 1 to 21, characterized in that it is a wastewater treatment plant in the device. 23. Use of a device according to one of claims 13 to 22 for preventing or reducing the formation of bulking sludge, scum and / or foam in sewage sludge, sewage or a suspension of particulate substances. 24. Use of a device according to one of claims 13 to 22 for influencing the Mischbiozönose in sewage sludge, wastewater or suspension of particulate substances, in which there is a decrease of filamentous microorganisms in favor of flocculating microorganisms in the sewage sludge, sewage or the Suspension of particulate substances comes. 25. Use according to claim 23 or 24, characterized in that a modification of at least one of the following parameters in the treated by the device sewage sludge, sewage or suspension more particulate Substances are: increase in denitrification, increase in chemical oxygen demand (COD), increase in biochemical oxygen demand (BOD), decrease in power consumption for treatment of sewage sludge, wastewater, suspension of particulate matter (P _ges ) _/ decrease in sludge volume index (ISV), decrease in Oxygen concentration in the aeration tank.