EP1945578A1

EP1945578A1 - Optoreactor

Info

Publication number: EP1945578A1
Application number: EP06805448A
Authority: EP
Inventors: Christian Uphoff
Original assignee: Georg Fritzmeier GmbH and Co KG
Current assignee: Georg Fritzmeier GmbH and Co KG
Priority date: 2005-10-19
Filing date: 2006-10-19
Publication date: 2008-07-23
Also published as: WO2007045228A1; DE102005050414A1; US20090130748A1

Abstract

The invention relates to a bioreactor for the treatment of industrial or domestic effluent, comprising a container and a packing, wherein a potential difference forms between the packing and container, which is provided with a device which prevents corrosion of the container as a result of the potential reversal due to the growth of a biofilm.

Description

Description Qptoreactor

The present invention relates to a bioreactor for the treatment of contaminated with organic or inorganic pollutants fluids according to the preamble of claim 1.

Bioreactors of this type are particularly found in small sewage treatment plants, which are mainly used for the treatment of domestic sewage. These . Small wastewater treatment plants are mostly already existing multi-chamber plants, which were equipped with an additional biological stage. The treated wastewater is either seeped after flowing through the small sewage treatment plant or forwarded to the next open water.

However, leachate from landfills or composting plants can also be treated with these bioreactors.

Bioreactors for this use are known for example from the patent applications DE 103 30 ^' 959.4 or the application FR2439. The bioreactors described therein consist of a photocatalytically coated container and a filling body which is arranged in the interior of the container, wherein the filling body contains a microbiotic mixture of photosynthetically active microorganisms and luminescent bacteria.

The degradation of the pollutants by means of this microbiotic mixture, the interaction of photosynthetic microorganisms and luminescent bacteria is exploited - a detailed description of the mode of action of the mixture can be found in the publications DE 100 62 812 and DE 101 49 447. Are also how in the Patent application DE 102 53 334, photosensitisers present, singlet oxygen and other radicals are formed, which accelerate the degradation of pollutants.

However, the design of the container and filling itself also influences the rate of degradation and quality. If, for example, as disclosed in FR2439, the photocatalytic layer is applied in a strip-like manner alternately with a diamond coating on the outer surface of the container wall, the diamond coating acts as a diamond electrode, in the region of which hydroxyl radicals form, due to the potential difference built up between the photocatalytic layer and the sorption surface of the filling body which make it possible to break even very sparingly soluble pollutants, such as rheumatism.

However, a disadvantage of these known bioreactors is that a biological film is formed on the container during operation of the bioreactor, and the container begins to corrode.

The object of the present invention is therefore to provide a bioreactor which prevents such corrosion.

This object is achieved by a bioreactor according to claim 1.

Basis of the present invention is the recognition that the orientation of the polarity of the container and packing due to the biofilm formation on the container wall during operation compensates in the course of time and even reversed, whereupon radicals increasingly increases the material of Attack container, which then leads to the corrosion to be prevented.

There are several ways to prevent this polarity compensation or reversal.

On the one hand, in a first particularly advantageous embodiment, the container and the filling body can be galvanically separated. This very simple possibility prevents an exchange of charges from taking place, which can lead to a polarity reversal. Very simply, such a galvanic separation can be achieved, for example, by the fact that the container is not made of stainless steel but of plastic.

In a further preferred embodiment of the invention, a power source is provided which is applied to the container, and thereby the potential of the container is kept constant. This is particularly advantageous because already existing bioreactors can be easily equipped with this additional power source, so that a costly replacement of the bioreactor and thus a long-term shutdown of the sewage treatment plant is unnecessary. This power source may consist, for example, in a solar cell, in a power supply unit or in a capacitor. It is particularly preferred if the voltage of the potential difference itself ensures the maintenance of the potential.

Furthermore, as shown in a third embodiment, a barrier layer, for example made of water glass, which is arranged below the photocatalytically active layer, can prevent a potential reversal from occurring. This solution is particularly advantageous for newly used bioreactors. Another advantageous possibility is the use of a sacrificial anode, which prevents corrosion. The great advantage of this is that the sacrificial anode is simply added to the existing bioreactor, so that a conversion or shutdown of a bioreactor in operation is unnecessary.

Further advantages and preferred embodiments are defined in the subclaims.

In the following the invention with reference to drawings and the associated descriptions will be shown even more clearly. They show:

FIG. 1 shows a schematic diagram of a multi-chamber pit with a retrofitted biological stage;

FIG. 2 shows a schematic elevational view of an exemplary bioreactor from the prior art consisting of container and filling body;

Figure 3 is a schematic representation of a first embodiment of the bioreactor according to the invention; and

Figure 4 is a schematic representation of a second embodiment of the bioreactor according to the invention;

1 shows a section through a small sewage treatment plant 1 with a biological stage - ie a bioreactor 2 and a mechanical stage 4, which is formed by a three-chamber Absetzgrube 4. It is in principle a space 6, which is divided by a respective partition 8 into three sub-chambers, of which in Figure 1, only a first chamber 10 and a further chamber 12 are shown. The to be cleaned Waste water flows to the three-chamber Absetzgrube through an inlet 14 and enters a first - not shown - chamber and can flow through passages 16 in the walls 8 in the next sub-chamber 12 and from there into the last sub-chamber 10. In the individual chambers 10 and 12 settleable substances settle by sedimentation, while floating matter on the liquid surface 18 to swim. The drain 20 is chosen so that the sediments and the floating matter remain in the chambers 10 and 12 and the purified wastewater is discharged without these impurities. For biological treatment, the bioreactor 2 is provided in the chamber 10 as a retrofit kit, which represents a biological stage. The main component of this bioreactor is a container 22, which is formed in the illustrated embodiment as a floating body, that is, he has enough buoyancy that he floats in the biological wastewater to be treated. For positional positioning of the container 22, a vertical guide 24 is arranged in the chamber 10, which may be supported for example on the partition wall 8 and / or the side walls of the three-chamber Absetzgrube 6 (see dashed lines in Figure 1). The container 22 is slidably disposed along this vertical guide 24 in the X direction in Figure 1, so that it is depending on the liquid level 18 within the chamber 10 as a float up or down movable.

In the container 22, a microbiotic mixture is introduced, which forms a biofilm. This microbiotic mixture consists in the illustrated embodiment of a proportion photosynthetically acting and a proportion of light-emitting microorganisms. The interplay between the photoreactive microorganisms and the luminescent bacteria results in the photosynthetic microorganisms being affected by the emitted light the luminescent bacteria are stimulated to photosynthesis. The microorganisms operate photosynthesis with hydrogen sulfide and water as starting material and release sulfur or oxygen. They can also bind nitrogen as well as phosphate and degrade organic and inorganic matter. With regard to the concrete composition of this mixed microbiotic culture, reference is made to the patent applications DE 100 62 812 A1 and DE 101 49 447 A1 of the Applicant for the sake of simplicity. With reference to this application, only the essential steps of this photodynamic degradation will be explained after the description of the embodiments.

By interaction of the microbiotic mixture and the catalytic surfaces of the container 22, a photodynamic degradation of organic substances occurs. This photodynamic degradation of substances is described for example in the application DE 102 53 334 of the applicant.

Figure 2 shows another embodiment of the container 22. In this embodiment, the container 22 is not funnel-shaped, but cylindrical in shape. The side walls of the container 22 are made of stainless steel in the illustrated embodiment and partially be provided with a photocatalytic coating 26. This coating may be formed on the inner peripheral wall of the container 22 and / or on the outer wall 28 as shown in FIG. In the illustrated embodiment, the container 22 is made of V4A and provided with a titanium dioxide coating. Instead of this titanium dioxide, indium tin oxide or the like can also be used. The outer wall 28 of the container 22 is provided with a plurality of apertures 30, so that the biological to be stabilized wastewater into the interior of the Can reach container 22. These apertures 30 may be punched, for example, and it is advantageous if the piercing burrs project inwards so that a slight growth of microorganisms in this area can take place. The lower end face 32 of the container is closed, so that the inflow of the waste water into the container 22 takes place substantially in the radial direction. The upper end face can also be closed. In the case where this upper surface is above the liquid level, sealing can be dispensed with.

In the interior of the container 22, an exchangeable filling body 34 is received, which, as shown in the elevational view, has a spiral-shaped structure. In the illustrated exemplary embodiment, this filling body 34 consists of a support 36, which may be, for example, a spiral-wound stainless steel sheet. On this helically wound carrier 36 made of stainless steel, a foam material, for example a PU foam is applied on both sides, which is coated or offset with activated carbon and, if necessary, nano-composite material. The PU foam forms a pore system, the walls of which are coated with activated carbon, so that a large mass transfer area is provided.

Specifically, in the illustrated embodiment, the carrier 36 consists of a two to three millimeters strong VA grid body, wherein the helical structure is formed by two grid surfaces, between which a semi-hard, open-cell PU foam with activated carbon coating is introduced. The arranged on the downward side of the helix bars 38 are provided with a photocatalytic surface, the mesh size is at these facing down Large areas approx. 10 - 12 mm. At the the upwardly facing large area of the spiral forming bars is no coating provided. The mesh size here is about 25 to 30 mm.

The microorganisms mentioned above can be introduced centrally via a dosing hose into the center of the spiral filling body 34. However, it is also possible to introduce these microorganisms with the nanocomposite materials into the pore system during the production of the filler 34. Very promising were experiments in which the microorganisms and nanocomposite materials were dissolved in chitosan and then added to these with the nano-composite materials mixture - for example, by impregnation - is applied to the filler, so that a continuous supply of microorganisms is eliminated and only at regular intervals replacement of the filling body 34 is required.

The PU foam is coated in the embodiment shown here on the downwardly facing side of the helix with a gel-like material of chitosan. In this chitosan, the nano-composite materials are embedded, each of which is a piezoelectric ceramic system of PZT short fibers with photocatalytic coatings. Furthermore, typical sewage treatment plants and biophysical microorganisms are embedded. On the upper side of the PU foam core only cationic chitosan Lac.tat aerobic microorganisms are incorporated.

The photodynamic degradation of the organic components is still supported by the photocatalytic coating of the container 22. For this purpose, the container 22 is located both on its inner surface and on its outer surface. surface with the photocatalytically active layer 26 - so for example, the titanium dioxide - coated. This layer is completely applied on the inner surface, ie on the side facing the filler body 34, while on the outer surface the titanium dioxide is applied in the form of strips 26, between which remain areas which are provided with a diamond coating 40.

Such a diamond coating 40 can be produced synthetically by heating methane and hydrogen and a suitable carrier substance, for example niobium, silicon or ceramic, in a vacuum chamber to temperatures of up to approximately 2000 °. It then comes to a reaction in which a diamond lattice is formed on the carrier. This coating 40 is then applied to the outer wall 28 of the container 22, so that with a photocatalytically active 26 and provided with a diamond layer 40 areas adjacent to each other. These areas 26, 40 extend in the longitudinal direction of the container 22. In the illustrated embodiment, the width of the strips 26 corresponds approximately to the distance of four hole-shaped apertures 30, while the width of the regions 40 is substantially smaller and approximately equal to the distance between two adjacent apertures 30 ,

In cooperation with the catalytic coating of the container 22 and the above-described coating of the helical filling body 34, a comparatively strong electromagnetic field arises. The resulting potential difference is applied to the regions provided with the diamond coating 40, which then act as diamond electrodes. As a result of this voltage, hydroxylradiakals, which hitherto have been difficult or not, are formed in the region of the diamond electrodes (regions 40) Convert degradable substances into harmless salts or carbon dioxide, which is discharged as a gas overhead from the basket. Ie. , in the bioreactor according to the invention run parallel to each other in parallel on the interaction of the photocatalytically active layer and the biofilm on the packing and by the diamond electrodes processes that lead to the almost complete degradation of the organic pollutants. Details about the resulting electromagnetic field are disclosed in the earlier application DE 103 30 959.4, so that further explanations in this regard are unnecessary.

However, it is problematic, as already described above, that the polarity of the electromagnetic field can be influenced by the growth with the biofilm in such a way that the polarity of container 22 and filling body 34 can be reversed. As a result, the hydroxyl radicals which nevertheless form on the diamond coating no longer migrate in the direction of the pollutants - that is, into the interior of the container towards the filling body 34, but can also react with the stainless steel of the container, which leads to corrosion. This is increasingly the case when, in addition, the conductivity of the wastewater is comparatively high (> 1400 μS / cm), which is the case in particular in the case of leachate treatment of landfills.

In order to prevent such corrosion, two particularly advantageous embodiment examples of the bioreactors according to the invention are described below, which are based on the bioreactor shown in FIG. 2 but do not permit polarity reversal.

FIG. 3 shows a first embodiment of the bioreactor according to the invention. In this case, between the container inner wall and filling body 34 is a galvanic Separation 42 inserted. This prevents a charge exchange between filling body 34 and container 22, so that the polarity of container 22 and filling body 34 is maintained. A particularly simple galvanic separation would also consist in the fact that the container is not made of stainless steel, but of plastic.

However, it is also possible simply to apply a barrier layer, for example from water glass, which comes to rest under the photocatalytic coating and the diamond coating, as corrosion protection.

FIG. 4 shows a second embodiment of the bioreactor according to the invention. In this example, the potential reversal is prevented by the application of an external power source 44. The external power source 44 may be a power supply, a solar cell or a capacitor. It is particularly preferred if the current produced by the bioreactor itself is used as a power source.

In particular, it is advantageous if the current source 44 with an open circuit voltage of max. 4.9 V and a current of max. 500 mA, since higher values can lead to destruction of the coating of the container. Under load, a voltage of 1, 5 to 2.2 V and a current of 500 mA is ideal to ensure optimum operation of the bioreactor can.

Instead of an external power source, a sacrificial anode can also be used. It is made of a material that is easier to corrode than the container's stainless steel and therefore has a higher attraction for the highly reactive radicals. Disclosed is a bioreactor for treating industrial or domestic wastewater, consisting of a container and a packing, wherein between filler and container a potential difference is formed, which is equipped with a device that causes corrosion of the container due to the growth of a biofilm caused potential reversal prevented.

REFERENCE CHARACTERS:

1 small sewage treatment plant

2 bioreactor

4 mechanical stage

6 wastewater treatment room

8 partition

10, 12 chambers

14 inflow

16 passages in wall

18 liquid surface

20 outflow

22 containers

24 vertical guidance

26 photocatalytic coating

28 outer wall of the container

30 openings in container

32 lower end face

34 packing

36 carriers

40 diamond coating

42 galvanic isolation

44 external power source

Claims

claims

A bioreactor for treating fluids contaminated with organic or inorganic pollutants, comprising a container (22) having at least one recess for the passage of the fluid to be treated, and a filling body (34) arranged inside the container (22) Container (22) and packing. (34) are formed so that a potential difference is formed, characterized in that there is further provided a device which is designed to keep the orientation of the potential difference constant.

2. bioreactor according to claim 1, wherein the device is a galvanic separation (42) between the container (22) and packing (34).

The bioreactor of claim 3, wherein the container walls are coated with a photocatalytically active layer (26), and the barrier layer is disposed below the photocatalytic layer (26).

The bioreactor of claim 1, wherein the device is a power source (44) connected to the container (22).

The bioreactor of claim 5, wherein the power source (44) has an open circuit voltage of about 4.9 volts.

6. bioreactor according to claim 5 or 6, wherein the current source (44) under load has a voltage of 1, 5 to 2, 2 volts.

A bioreactor according to any one of claims 5 to 7, wherein the current source (44) has a current of 500 mA.

8. Bioreactor according to one of claims 5 to 8, wherein the power source (44) is a solar cell, a power supply and / or a capacitor.

9. bioreactor according to claim I ₇ wherein the device is a sacrificial anode.

10. Bioreactor according to one of the preceding claims, wherein the device is a barrier layer, in particular of water glass, which is arranged on the container (22).

11. Bioreactor according to one of the preceding claims, wherein the container (22) is made of plastic.

12. Bioreactor according to one of claims 1 to 10, wherein the container (22) made of stainless steel, in particular of V4A.

13. Bioreactor according to one of the preceding claims, wherein the container walls are coated with a photocatalytically active layer (26), in particular with titanium dioxide or indium tin oxide, which is applied at least on the outer peripheral surface in sections, and between the with the photocatalytic layer (26). provided areas a diamond coating (40) is applied.

14. Bioreactor according to claim 13, wherein the photocatalytic layer (26) and the diamond layer

(40) strip-shaped in the longitudinal direction of the container (22) are applied.

15. Bioreactor according to one of the preceding claims, wherein the filler body (34) comprises a microbiotic mixture, preferably with a proportion of photosynthetic and a proportion of light-emitting microorganisms.