DE102005036470B4 - Process and wastewater treatment plant for the treatment of radioactively contaminated wastewater - Google Patents

Abstract

Process for the treatment of radioactive waste water, which comprises two biological clarification stages with two clarification tanks, which are operated at a pressure below the ambient pressure, whereby in the first clarification stage (a) radioactive waste water is fed to a first clarification vessel (B), (b) the first The clarification tank (B) is equipped with a fixed bed designed as a microbial growth area or packing elements (11) as a microbial growth area, (c) the fixed bed or the packing elements (11) are supplied with regulated oxygen-containing gases which, after flowing through the fixed bed or the packing elements (11 ), insofar as they are not consumed in the clarification, are at least partially fed back to the fixed bed or the packing (11) together with the gases produced during the clarification, (d) the first clarification tank (B) via at least one outlet (5 and / or 10) sedimented sludge is removed, (e) partially from the first clarification tank (B) via at least one outlet (24) treated wastewater is removed and in the second treatment stage ...

Description

The present invention relates to a process for the treatment and purification of any radioactively contaminated effluents, in particular those from radiological departments of hospitals. Furthermore, the invention relates to a wastewater treatment plant, which can be used in the process according to the invention.

It is known to store radioactive effluents in containers prior to discharge into the general sewer system until the radioactivity is below the limit. For example, since this process takes about 1 year in hospital radiology, the storage capacity must be based on the annual wastewater volume of the respective radiology ward. This process is associated with an enormous space requirement and high investment costs for the complex storage containers. The odor nuisance associated with this process is also difficult to control.

A second option for wastewater treatment is to pass the wastewater over activated carbon, which binds some of the radioactive material. However, the use of activated carbon is associated with high costs and a decontamination of the waste water below the permissible limit is difficult. In addition, due to the organic load, the method is difficult to control because the activated carbon filters, among other things by the forming sludge, easily clog. Also in this process, the odor nuisance is difficult to control.

Another method attempts to solve the above-mentioned problems insofar as a biological purification of the water takes place. In certain cases, for example, the radioactive isotope ¹³¹ iodine is largely retained in the biomass. This protects downstream absorption plants and increases the absorption capacity of ¹³¹ Iodine.

In the DE 692 02 520 T2 discloses methods and apparatus for treating radioactive contaminated oils and solvents wherein the oils and solvents are treated by preselected microorganisms in the presence of air and a large amount of water.

An essentially biological process for the treatment of surfactant-containing and organically contaminated radioactive washing waters from nuclear installations is described in US Pat DE 195 21 959 A1 described. In this process, wash waters under aerobic conditions are subjected to microbial degradation of the degradable ingredients. Subsequently, the solids contained are separated. This method is disadvantageous because after the microbial degradation of the wash water about 90% of the biomass must be removed, with the remaining 10% used to inoculate further wash water. The method therefore includes periods in which the efficiency of the system is low, since the degrading microorganisms must first be formed again.

The object of the present invention was to improve the efficiency of biodegradation, to reliably prevent uncontrolled escape of radioactive aerosols or gases and to improve the retention, in particular of radioactive ¹³¹ Iodine as well as the radioactive elements of the transition groups. Another aim was to design the process and the plant so that only small amounts of gases have to be aftertreated and it is possible that also tritium in the form of water, which forms during biodegradation, are retained with the formed gases can. In addition, the removal of other radioactive isotopes, such as ¹⁴ C should be possible, as they occur in organic contaminants.

These tasks could be solved by a method which comprises two biological treatment stages with two clarification tanks operating at a pressure below ambient, wherein in the first treatment stage (a) radioactively contaminated wastewater is fed to a first clarifier, (b) the first (C) the oxygen-containing gases are supplied to the fixed bed or the packing regulators, which together after flowing through the fixed bed or the packing, as far as they are not consumed in the clarification, together with a fixed bed or packing designed as a microbial growth surface as microbial growth surface with the gases formed during the clarification, at least partially recirculated to the packed bed or packing, (d) sedimented sludge is taken from the first clarifier via at least one outlet, (e) the first clarifier is at least partially cleared via at least one outlet water is removed; and in the second clarification stage (a) the partially clarified waste water of the first stage is fed to a second clarification tank, (b) the second clarification tank is equipped with a microbial growth surface designed fixed bed or packing as a microbial growth surface, (c) the fixed bed or the packing regulated oxygen-containing gases are supplied, which, after flowing through the fixed bed or the packing, as far as they are not consumed in the clarification, together with the gases formed during the clarification are at least partially fed back to the fixed bed or the packing (d) the clarifier over at least one outlet sedimented sludge is removed; and wherein the supply of oxygen-containing gases in the treatment stages or the removal of spent gases from the treatment stages is controlled by means of a pressure measuring point downstream of the second clarification stage.

In the following, the method according to the invention will be explained in more detail by means of specific embodiments with reference to the drawing, in which: A a storage tank, B a first clarifier, C a second clarifier, D a settling tank, E an adsorber column, 1 a compressor for the recycling of (oxygenated) gases, 2 a solenoid valve for the tracking of (oxygen-containing) gases, 3 a pressure line, 4 Ventilation unit, for example a diaphragm aerator, 5 a suction nozzle for sedimented sludge, 6 Sedimentation and thickening area for the sludge, 7 Baffle for flow calming, 8th sedimentation, 9 Siphon, 10 Bottom outlet, 11 ventilated area with fixed bed and / or packing, 12 Pressure measuring point, 13 Wash, 14 Slotted screen and / or sand trap, 15 dosing pump, 16 Reservoir for reagents, precipitants and flocculants, 17 Water pump with storage tank and float control, 18 sieve tray, 19 Screen plate for retaining porous fillers, 20 Extraction to the washer, with the option of venting a part into the atmosphere or returning it to the circulation, 21 lamella, 22 Kompartimentierungsvorrichtung, 23 Clarifier wall and 24 Outlet to the second clarifier.

An advantageous embodiment of the method according to the invention provides that the recirculated gas (via 1 . 3 . 4 and 11 ), consisting of the not consumed in the fermentation, oxygen-containing gas and the gases resulting from the clarification or fermentation from the first and / or second clarifier (B and C) is removed and before returning to the respective container, by an absorption -Contraption ( 13 ), which allows the binding of, for example, formed ¹⁴ CO ₂ . Such absorption devices are also preferably suitable for the separation of aerosols and are preferably integrated into the circulation in the form of interchangeable cartridges.

Likewise, it is advantageous if, from time to time, some of the gases which make up the fixed bed ( 11 ) or the packing ( 11 ) are not recycled into the gas circulation, but are taken from the first and / or second clarifier (B and / or C), whereby also here optionally an absorption device ( 13 ) is followed, for example, to bind incurred ¹⁴ CO ₂ . The extracted used gases can still contain oxygen, but disproportionately, compared to air, loaded with "ballast gases" such as carbon dioxide, nitrogen and noble gases. The removal of some of these gases, for example by suction ( 20 ), thus preventing an enrichment of nitrogen and inert gases such as argon.

Both the recirculation of discharged gases into the circuit, as well as the final discharge of gases from the system can be supported by gas-tight pumps. This can be done by means of separate pumps or only one pump, if this is followed by both the pressure line for the gas recirculation and the pressure line for the discharge of the gas and both lines can be closed or opened separately.

In order to prevent the sedimentation of the sediments formed during the fermentation in the first and second clarification stages (B and C) by the circulation of the gases, it is advantageous to use the gas supply ( 4 ) so that they are below the packed bed ( 11 ) or the filling body ( 11 ) and the fixed bed or packed area ( 11 ) the clarifier (B and C) of a preferably funnel-shaped tapered bottom portion of the clarifier (B and C) separates. Preferably, at the bottom of the clarifier is a bottom outlet ( 10 ) to remove the sediments.

There is also preferably a spatial separation between the outlet leading into the second clarification tank (( 24 ) and the fixed bed or the packing ( 11 ) of the first clarifier (B). This spatial separation can be achieved, for example, by one or more compartmentalizing devices ( 22 ), for example, sheets are obtained, which before the second clarifier (C) leading outlet ( 24 ) are arranged. Preferably, such compartmentation devices are ( 22 ) substantially parallel to the clarifier wall ( 23 ) and spaced therefrom. Particularly preferably, the compartmenting device ( 22 ) from an area above the outlet leading into the second clarifier (C) ( 24 ) over this away into the preferably funnel-shaped bottom portion of the clarifier (B) to complete with this (zones 8th and 6 ). The spatial separation effects, preferably in combination with one or more baffles ( 7 ), which are preferably substantially parallel between the clarifier wall ( 23 ) and compartmentalization device ( 22 ), a flow calming between compartmentalizing device ( 22 ) and the outlet leading into the second clarifier (C) ( 24 ). Sludge can sediment in the flow-calmed compartment (zones 8th and 6 ), for example, via a suction ( 5 ) can be removed. The extraction nozzle ( 5 ) is preferably located between the Klärbehälterwand ( 23 ) and the end of the bottom part of the compartmenting device ( 22 ).

A corresponding embodiment is also advantageous in the second clarification tank (C), in which case instead of the outlet to a further clarification tank, the outlet to the pressure measuring point (C) ( 12 ) stands. If instead of the fixed bed ( 11 ) Packing ( 11 ), optionally used in the form of a floating bed, so it is recommended in the upper part of the compartmentalizing device ( 22 ) a separating device ( 19 ), such as to provide a screen plate, with which the filling body ( 11 ). This applies to both the first and the second clarifier.

By the pressure measuring point ( 12 ) adjustable gas supply (over 2 ) into the two clarification tanks (B and C) can in particular by solenoid valves ( 2 ) are pressure controlled. In this way, for example, when the oxygen partial pressure drops again, oxygen-containing gas, such as air, may be supplied to the clarifier to obtain or re-adjust aerobic conditions.

The connection ( 9 ) between the first and second clarifier (B and C) is preferably configured siphon-like. A siphon-like configuration is also for the connection ( 9 ) of the second clarification tank (C) with an optional downstream third clarification stage (D), wherein the pressure measuring point ( 12 ) following the second clarification tank (C) in front of the siphon ( 9 ) is switched.

Since a first loading of the clarifier (B and C) may not be sufficient microbial growth of the fixed bed ( 11 ) or the filling body ( 11 ), it is recommended in such cases to use mixed populations of aerobically degrading microorganisms of any biological sewage treatment plants for inoculation. Suitable examples are pseudomonads, corynebacteria and similar bacterial strains.

In a preferred embodiment, the first clarifier (B) is preceded by a feed tank (A), which in turn preferably has a screen ( 14 ) and a sand trap ( 14 ) is connected upstream.

In a further preferred embodiment, the second biological clarification stage (C) is followed by a third clarification stage (D). Behind the second stage (C) downstream pressure measuring point ( 12 ) can be, for example, via a pump ( 15 ) Precipitant and flocculant from a reservoir ( 16 ) respectively. Since in some cases not all radioactive substances are bound by biomass, it is advantageous to remove the remaining organic or inorganic compounds or ions with flocculants and precipitants. One way of removing radioactive iodide is, for example, by precipitating it with water-soluble silver salts. However, since the iodide concentration is usually well below the solubility product of silver iodide, it is advisable to enrich the wastewater of the second stage (C) first with non-radioactive iodides, such as sodium iodide and at a sufficiently high iodide concentration, the total iodide with water-soluble silver salts, such as silver nitrate to precipitate. In this way, even the smallest remains of radioactive iodide can be removed by a total precipitation.

For example, iron or aluminum chloride are suitable as further precipitating or flocculating agents.

The precipitation and flocculation products are preferably passed into a third clarifier (D). The optional third clarification container (D) is preferably designed so that it has a funnel-shaped bottom and above it a tightly sealed with the clarifier wall filter ( 21 ), for example, a lamellar filter is attached. The precipitation and flocculation products can pass through a tube which passes through the filter ( 21 ) is led into the lower area of the third clarification tank and sedimented in the lower area of the clarification tank (D). The supernatant clarified water penetrates the filter ( 21 ) from bottom to top and can be removed in clarified form. The precipitation and flocculation products collect in the preferably funnel-shaped lower region of the third clarification stage and can be obtained, for example, by means of a suction nozzle (FIG. 5 ).

Usually already provides the second stage (C) water in good quality, which does not necessarily require further clarification. The radioactivity is usually reduced by 95 to 99.9% based on the untreated wastewater. However, the precipitation and / or flocculation step again increases the quality of the treated wastewater by separating insoluble particles and suspended matter.

In order to obtain the clarified water in further improved quality, it is particularly advantageous to pass it in a fourth stage through an adsorber filter column (E) which contains a weakly basic strongly macroporous anion exchanger, a cation exchanger, iron-doped macroporous polyacrylate and activated carbon ,

For example, Lewatit MP 64 from Bayer AG is suitable as the weakly basic strongly macroporous anion exchanger. An example of one suitable cation exchanger is Lewatit 260/207 (Bayer AG). Iron-doped macroporous polyacrylate is, for example, iron-doped Stockosorb 500 (a crosslinked acrylamide / acrylic acid copolymer) from Degussa AG. Grain activated carbon is preferably suitable as the activated carbon component.

The ingredients may be in mixture or layers. It is especially recommended that the activated carbon forms the lowest layer of the filter, as it has a supporting effect. The other filter components can be present in mixture or else in layers. The proportions of the filter components vary depending on the wastewater source. Contains the prepurified wastewater significantly anions, so for example, a correspondingly larger amount of anion exchanger is selected. It is also possible to switch two or more such filters one behind the other in order to obtain an even better cleaning effect.

The inventive method allows, unlike the method described in the introduction, to obtain in a small space with only two mandatory treatment stages, from radioactively contaminated wastewater in only about one day clarified water, which can be supplied without post-treatment of municipal sanitation and thus the volume radioactive waste is greatly reduced.

Another object of the present invention is a wastewater treatment plant for the purification of radioactively contaminated wastewater, which can be used in the process according to the invention.

The wastewater treatment plant according to the invention for cleaning radioactively contaminated wastewater consists of a first clarifier, this first clarifier with a waste water inlet, with a suitable microbial growth fixed bed, Gaszuführvorrichtung, a gas sampling device, at least one outlet for sewage sludge and an outlet for teilgeklärtes water equipped is; wherein the Gaszuführvorrichtung is arranged so that the gas to be supplied can flow through the fixed bed, and the Gasabführvorrichtung is arranged so that via this optionally complete or partial recycling of the fixed bed gases flowing through the Gaszuführvorrichtung or removal of at least a portion of the fixed bed by flowing Gases from the wastewater treatment plant, can be made, the outlet for sewage sludge is disposed in a sedimentation of the first clarifier, and the outlet for partially clarified water is disposed above the sedimentation; and a second clarifier, said second clarifier having a partially clarified water inlet, a fixed bed suitable for microbial growth and / or particulates suitable for microbial growth, a gas delivery device, a gas sampling device, at least one sewage sludge outlet, and an outlet for clarified water, wherein the inlet for partially clarified water is connected to the outlet for partially clarified water of the first clarifier, the gas supply device is arranged so that the gas to be supplied can flow through the fixed bed, and the Gasabführvorrichtung is arranged so that over these optionally a complete or partial recycling of the fixed bed and / or the filler gas flowing through gases in the Gaszuführvorrichtung or a removal of at least a portion of the fixed bed and / or the packing flowing through gases from the wastewater treatment plant, erf and the clarified water outlet is located above the sedimentation zone and is followed by a pressure measuring point that controls the gas supply devices and the gas discharge devices of the first and second clarification tanks.

Preferably, the partially clarified water inlet of the second clarifier is connected to the partially clarified water outlet of the first clarifier by a siphon.

In a further preferred embodiment of the waste water treatment plant according to the invention is preceded by a closed inlet device, which is fed from a feed tank, which in turn may be preferably preceded by a screen.

Quite particularly preferred are inventive wastewater treatment plants comprising a third clarifier, which is preferably connected by means of a siphon with the second clarifier, wherein the third clarifier is preferably supplied via a pump with precipitants or flocculants from a reservoir and having a filter having a Clear water section separates from a sedimentation, wherein the sedimentation is supplied via a supply line for precipitated or flocculated wastewater and in which an outlet is arranged, which allows the removal of the precipitated and / or flocculated sediments.

In order to enable further purification, it is recommended that the wastewater treatment plant according to the invention comprises, in addition to the third clarifier, a fourth clarifier fed with the clarified water of the third clarifier and accommodating an adsorber filter column which, as described above, is a weakly basic highly macroporous one Anion exchanger, a cation exchanger, contains iron-doped macroporous polyacrylate and activated carbon. As mentioned above, the composition of ingredients may vary depending on the source and composition of the wastewater.

Another object of the present invention is a wastewater treatment plant for the purification of radioactively contaminated wastewater consisting of a first and a second clarifier, said first clarifier with a waste water inlet, with a suitable for microbial growth fixed bed and / or packing, which are suitable for microbial growth, a Gas supply, a gas sampling device, at least one outlet for sewage sludge and a outlet for partially clarified water is equipped. The gas supply device is arranged so that the gas to be supplied can flow through the fixed bed and / or the packing. The Gasabführvorrichtung is arranged so that on this either a complete or partial recycling of the fixed bed and / or the filler gas flowing through gases in the Gaszuführvorrichtung or a removal of at least a portion of the fixed bed and / or the packing flowing through gases from the wastewater treatment plant, can take place , The sewage sludge outlet is located in a sedimentation zone of the first clarifier, and the partially clarified water outlet is located above the sedimentation zone. The second clarifier has an inlet for partially clarified water, and is provided with a microbial growth suitable fixed bed and / or packing suitable for microbial growth, as well as a gas supply device, a gas sampling device, at least one outlet for sewage sludge and an outlet for clarified water, fitted. The partially clarified water inlet is connected to the partially clarified water outlet of the first clarifier. The gas supply device is arranged so that the gas to be supplied can flow through the fixed bed and the gas discharge device is arranged so that via this either a complete or partial return of the fixed bed and / or the filler gas flowing through gases in the Gaszuführvorrichtung or a removal of at least a portion of the fixed bed and / or the filling material flowing through gases from the wastewater treatment plant, can take place. The sewage sludge outlet is located in a sedimentation area of the second clarifier, while the clarified water outlet is above the sedimentation area and is followed by a pressure measuring point which controls the gas supply and gas discharge devices of the first and second clarifiers.

In a preferred embodiment of the wastewater treatment plant according to the invention, the gas removal device is followed by an absorption device, which is preferably suitable for absorbing carbon dioxide. Particularly preferably, this contains lime milk, calcium hydroxide and / or calcium oxide.

In a further preferred embodiment of the wastewater treatment plant according to the invention there is a spatial separation between the leading into the second clarifier outlet of the first clarifier and / or the outlet to the pressure measuring point of the second clarifier and the respective fixed bed and / or the packing, wherein the spatial separation by a or more Kompartimentierungsvorrichtungen is achieved, which are arranged in front of the leading into the second clarifier outlet of the first clarifier and / or the outlet to the pressure measuring point of the second clarifier substantially parallel to the clarifier wall and spaced therefrom. The compartmenting device preferably extends from an area above the outlet of the first clarifier tank leading into the second clarifier tank or the outlet to the pressure measuring point of the second clarifier tank up to the preferably funnel-shaped bottom area of the clarifier tank in order to complete it.

Preferably, the wastewater treatment plant comprises a third clarifier, which is connected downstream of the pressure measuring point and which contains a filter which divides the clarifier into an upper and a lower compartment. The lower compartment has an inlet which serves to supply the clarified water from the second clarifier and the feed of precipitant and flocculant, and the upper compartment contains an outlet for the clarified water. The feed of the precipitation and flocculation can also be done before the inlet of the third clarifier, so that the inlet is already supplied to a precipitation or flocculation of treated wastewater.

In a preferred embodiment, the wastewater treatment plant comprises a further clarification tank which is connected to the second or third clarification tank via lines and which comprises an adsorber filter which contains a weakly basic strongly macroporous anion exchanger, a cation exchanger, iron-doped macroporous polyacrylate and activated carbon.

The connections between the first and second clarifier and the second and third clarifier are preferably designed as a siphon. The connection between the first and second clarifier can be interposed a pressure measuring point.

Another object of the present invention is a clarification stage of a wastewater treatment plant according to the invention which comprises a clarifier comprising an adsorber filter containing a weakly basic strongly macroporous anion exchanger, a cation exchanger, iron-doped macroporous polyacrylate and activated carbon.

Claims (22)

A process for the treatment of radioactive effluents, comprising two biological treatment stages with two clarification tanks, which are operated at a pressure below ambient pressure, wherein in the first stage (a) radioactively contaminated wastewater is fed to a first clarifier (B), (b) the first Clarifying container (B) with a fixed bed or packing (designed as microbial growth surface) ( 11 ) is equipped as a microbial growth surface, (c) the fixed bed or the packing ( 11 ) are fed oxygen-containing gases which, after flowing through the fixed bed or the packing ( 11 ), as far as they are not consumed in the clarification, together with the gases formed during the clarification, at least partially again the fixed bed or the packing ( 11 ), (d) the first clarifier (B) via at least one outlet ( 5 and or 10 sedimented sludge, (e) the first clarifier (B) via at least one outlet ( 24 ) partially clarified wastewater is removed and in the second clarification stage (a) the partially clarified waste water of the first stage is fed to a second clarification tank (C), (b) the second clarification tank (C) is designed as a microbial growth surface fixed bed or packing ( 11 ) is equipped as a microbial growth surface, (c) the fixed bed or the packing ( 11 ) are fed oxygen-containing gases which, after flowing through the fixed bed or the packing ( 11 ), as far as they are not consumed in the clarification, together with the gases formed during the clarification, at least partially again the fixed bed or the packing ( 11 ), (d) the clarifier (C) via at least one outlet ( 5 and or 10 sedimented sludge is removed, and wherein by means of a second clarification stage downstream pressure measuring point ( 12 ) the supply of oxygen-containing gases to the treatment stages or the removal of spent gases from the treatment stages is regulated. Method according to claim 1, wherein the first clarification container (B) has a fixed bed designed as a microbial growth surface ( 11 ) and / or the second clarifier (C) with packing ( 11 ) is equipped as a microbial growth area. Process according to claim 1 or 2, wherein in the first and / or second clarification stage the oxygen-containing gases which are not consumed during the clarification, together with the gases formed during the clarification, before re-feeding to the fixed bed and / or the random packings ( 11 ) by an absorption device ( 13 ). Method according to claim 3, wherein the absorption device ( 13 ) is suitable for binding CO ₂ . Method according to one of claims 1 to 4, wherein in the first and / or second stage of clarification, the oxygen-containing gases not used in the clarification, together with the gases formed in the clarification, in part not the re-supply to the fixed bed and / or the packing ( 11 ), but the clarification tanks (B and C) are removed. Process according to claim 5, wherein the extracted gases are conveyed through an absorption device ( 13 ). Method according to claim 6, wherein the absorption device ( 13 ) is suitable for binding CO ₂ . Method according to at least one of claims 1 to 7, wherein in the first and second clarification containers (B and C) the devices ( 4 ) are arranged for the supplied oxygen-containing gas so that these below the packed bed and / or the packing ( 11 ) and the fixed bed and / or the packing ( 11 ) are separated from a preferably funnel-shaped, flow-calmed bottom region of the clarifier (B and C). Method according to at least one of claims 1 to 7, wherein a spatial separation between the outlet leading into the second clarification container (C) ( 24 ) of the first clarification tank (B) or the outlet to the pressure measuring point ( 12 ) of the second clarification container (C) and the respective fixed bed and / or the packing ( 11 ), wherein the spatial separation by one or more compartmentalization devices ( 22 ), which leads in front of the outlet leading into the second clarifier (C) ( 24 ) of the first clarification tank (B) or the outlet to the pressure measuring point ( 12 ) of the second clarification container (C) substantially parallel to the clarifier wall ( 23 are arranged and spaced from one another, and which extend from an area above the outlet leading into the second clarifier (C) ( 24 ) the first clarifier (B) or the outlet to the pressure measuring point ( 12 ) of the second clarification container (C) extend over the latter into the preferably funnel-shaped bottom region of the clarification container (B and C) in order to complete it. Method according to at least one of claims 1 to 9, wherein the radioactively contaminated wastewater fed to the first container (B) is conveyed via a sieve system and / or a sand trap ( 14 ) is prepurified. The method according to at least one of claims 1 to 10, wherein the second clarification stage is followed by a third clarification stage, in which a post-treatment of the clarified wastewater of the second clarification stage takes place with precipitants and / or flocculants. The process of claim 11 wherein iodide is added to the second stage clarified effluent to a concentration above the solubility product of silver iodide, then precipitating silver iodide with a silver salt solution, and removing the precipitated silver iodide. A method according to any one of claims 1 to 12, wherein the clarified wastewater after the second or third stage of clarification by an adsorber filter column (E) is passed, which contains a weakly basic strongly macroporous anion exchanger, a cation exchanger, iron-doped macroporous polyacrylate and activated carbon , Method according to at least one of claims 1 to 13, wherein the regulation of the supply of oxygen-containing gases and the removal of gases via the pressure measuring point ( 12 ) he follows. Wastewater treatment plant for the treatment of radioactively contaminated effluents comprising a first clarification tank (B), this first clarification tank (B) having a waste water inlet, a fixed bed suitable for microbial growth and / or packing ( 11 ), which are suitable for microbial growth, a gas supply device ( 4 ), a gas sampling device, at least one outlet ( 5 and or 10 ) for sewage sludge and an outlet ( 24 ) for partially clarified water, whereby via the gas supply device ( 4 ) the gas to be supplied to the fixed bed and / or the packing ( 11 ) flows through the gas discharge either a complete or partial return of the fixed bed and / or the packing ( 11 ) flowing through the gas supply device or a removal of at least a portion of the fixed bed and / or the packing ( 11 ) passing through the wastewater treatment plant, the outlet ( 5 and or 10 ) is arranged for sewage sludge in a sedimentation of the first clarifier (B), and the outlet ( 24 ) for partially clarified water above the sedimentation area, and a second clarification tank (C), this second clarification tank (C) having a partially clarified water inlet, a fixed bed suitable for microbial growth and / or packing ( 11 ), which are suitable for microbial growth, a gas supply device ( 4 ), a gas sampling device, at least one outlet ( 5 and or 10 ) for sewage sludge and an outlet for clarified water, whereby the inlet for partially clarified water with the outlet ( 24 ) for partially clarified water of the first clarification tank (B) is connected via the gas supply device ( 4 ) the gas to be supplied to the fixed bed and / or packing ( 11 ) flows through the gas discharge either a complete or partial return of the fixed bed and / or the packing ( 11 ) flowing through the gas supply device or a removal of at least a portion of the fixed bed and / or the packing ( 11 ) passing through the wastewater treatment plant, the outlet ( 5 and or 10 ) is arranged for sewage sludge in a sedimentation area of the second clarification tank (B), and the outlet for clarified water is arranged above the sedimentation area and from a pressure measuring point ( 12 ) which controls the gas supply devices and the gas discharge devices of the first and second clarification tanks (B and C). Wastewater treatment plant according to claim 15, that the gas discharge device comprises an absorption device ( 13 ) is connected downstream. Wastewater treatment plant according to claim 16, wherein the absorption device ( 13 ) is capable of absorbing carbon dioxide. Wastewater treatment plant according to claim 17, wherein the absorption device ( 13 ) Contains lime milk, calcium hydroxide and / or calcium oxide. Wastewater treatment plant according to at least one of claims 15 to 18, wherein a spatial separation between the outlet leading into the second clarifier (C) ( 24 ) of the first clarification tank (B) or the outlet to the pressure measuring point ( 12 ) of the second clarifier (C) and the respective fixed bed and / or the packing ( 11 ), wherein the spatial separation by one or more compartmentalization devices ( 22 ), which leads in front of the outlet leading into the second clarifier (C) ( 24 ) of the first clarification tank (B) or the outlet to the pressure measuring point ( 12 ) of the second clarification container (C) substantially parallel to the clarifier wall ( 23 are arranged and spaced therefrom and which extend from an area above the outlet leading into the second clarifier (C) ( 24 ) of the first clarification tank (B) or the outlet to the pressure measuring point ( 12 ) of the second clarification container (C) extend over the latter into the preferably funnel-shaped bottom region of the clarification container (B and C) in order to complete it. Waste water treatment plant according to at least one of claims 15 to 19, which comprises a third clarification tank (D) which is connected downstream of the pressure measuring point ( 12 ) and which a filter ( 21 ), which divides the clarifier (D) into an upper and a lower compartment, the lower compartment having an inlet which serves to supply the clarified water from the second clarifier (C) and the feed of precipitant and flocculant, and the upper compartment containing an outlet for the clarified water. Waste water treatment plant according to at least one of claims 15 to 20, which comprises a further clarification tank following the second or third clarification tank (C or D) and which comprises an adsorber filter (E) comprising a weakly basic strongly macroporous anion exchanger, a cation exchanger , iron-doped macroporous polyacrylate and activated carbon. Wastewater treatment plant according to at least one of claims 15 to 21, wherein the connections between the first and second clarification tanks (B and C) and the second and third clarification tanks (C and D) as a siphon ( 9 ) are configured.

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