DD300362A7 - Process and reactor for anaerobic-aerobic wastewater treatment with increased C, P and N elimination - Google Patents

Abstract

The invention relates to a process and a reactor for the biological treatment of wastewater having an increased C, P and N elimination performance using fluidizable carrier materials in small and medium-sized wastewater treatment plants. According to the invention, the carrier materials are recirculated via an unpowdered fluidized bed zone and a vented fluidized bed zone. In the reactor Leitwaende are arranged to form the different zones Leitwaende. The ventilation is done by means of an intensive ventilator. The carrier material used has a density of 0.4 to 0.95 g / cm3 and a diameter of 1 to 30 mm. When using a Tauchstrahlbeluefters can be arranged under the Muendungsquerschnitt a Fuehrungsrohr. Fig. 1 {Waste water treatment, anaerobic, aerobic, biological; Traegermaterial; Flieszbettzone; Fluidized bed zone; Kreislauffuehrung; baffles; Ventilation; Intensivbeluefter; Density; TUBE GUIDE}

Description

For this purpose 3 pages drawings Field of application of the invention

The invention relates to a reactor for biological treatment of wastewater with increased C, P and N elimination

using fluidizable materials in small and medium-sized wastewater treatment plants.

Characteristic of the known state of the art

Starting from the known process steps of a simultaneous C, P and N elimination, various process engineering and apparatus solutions with and without carrier fixation are described in the literature. In DE 3215404 it is stated that in particular in the phosphate removal the biomass should be alternately exposed to aerobic and anaerobic conditions. Therefore, it is proposed that the wastewater be treated in at least two reaction zones and the treatment in a time cycle under aerobic, anaerobic and optionally

Anoxic conditions is performed. The biomass fixed on the carrier material remains in the respective reaction zone and is subjected to aerobic, anaerobic and anoxic conditions in a specific time cycle. The device described requires a great effort in terms of additional installations and necessary control and Regolungsmechanlsmen.

A number of other methods and corresponding arrangements for combined P and N elimination are described in the literature. So z. B. In DE 3301643 a method and apparatus is shown, carried with the carrier material from the anaerobic, optionally via the anoxic to the aerobic zone and at the same time an equal amount of carrier material from the aerobic zone via the anoxieche back to the anaerobic zone. The anaerobic zone let be formed in one embodiment as Wanderbott. This invention can be realized only with a high expenditure on equipment. Additional conveyors significantly increase the operating and maintenance costs as well as the susceptibility to faults.

Object of the invention

The object of the invention is to reduce the expense of complex C, P and N elimination in wastewater treatment, especially in small and medium size digested sludge plants.

Explanation of the essence of the invention

The invention has for its object to form by a method and a reactor using fluidizable carrier materials and a ventilation device different zones of increased C, P or N-Elimlnierungslelstungen that make use of the advantages of changing anaerobic-aerobic wastewater treatment. According to the invention, this object is achieved in that the fluidizable carrier materials contained in a reactor for immobilizing biomass via an unaerated fluidized bed zone and a vented fluidized bed zone are recycled. The automatic removal of the support material from the fluidized bed zone and Wiederzuführun'g in this zone carried by the turbulence by means arranged in the fluidized bed zone Intenslvbelüfteranlage. Carrier materials are entrained from one end of the open-ended fluidized bed zone and re-deposit at the opposite end of that zone. As a result, the carrier material flows slowly in the direction of the extraction point in the non-aeration zone and is subsequently swirled in the ventilated zone. Return sludge and / or a partial stream from the reactor effluent are introduced wholly or partly into the non-aerated fluidized bed zone. The wastewater to be treated is also completely or partially introduced into this zone.

According to the invention the object is further achieved in that the reactor is divided by one or more baffles in a ventilated Wirbelbettzono and an unaerated fluidized bed zone. Aeration In the fluidized bed zone, intensive aerators are used. A coarse-bubble aeration is carried out with a dip-tracer from above or a pressure aeration system from the bottom of the reactor. The baffles extend from above the reactor floor to just above the water level (10 to 150mm). The feed for wastewater, return sludge and / or a partial flow from the reactor outlet opens into the flowbottom zone. When using a submersible aerator, the waste water can be completely or partially supplied via this. Irn entire reactor is granular or lumpy, swirling carrier material having a density of 0.4 to 0.95 g / cm ³ and a diameter of 1 to 30mm included.

The treated waste drain is provided with a backing retention device. The volume fraction of the fluidized bed zone in the total reactor volume is 5 to 40%. in the reactor is so much support material that the fluidized bed zone is filled in the region of the submersible walls. In the fluidized bed zone, a proportion of 10-40 vol.% Of carrier material is contained in the operating state. When using a Tauchstrahlbelüfters to arrange, with its liquid supply from the outlet of the reactor itself or via the inlet.

Under the mouth cross-section of the Tauchstrahlbelüfters axially axial guide tube may be arranged, the upper edge is in the operating state below the water level.

When using Drucktuftbelüftern these are preferably to be arranged laterally at the bottom of the fluidized bed zone. The function of the reactor is as follows:

The reactor according to the invention contains wastewater activated sludge mixture and fluidizable carrier material. The fluidized bed zone is ventilated by means of intensive aerators. This results in a strong turbulence of the specific light growth carrier and the suspended biomass. From the lower fluidized bed zone, carrier particles are constantly deflected below the area of the fluidized bed zone by reversal and transverse flows. Carrier particles constantly accumulate in the unventilated reactor zone due to buoyancy. This forms a compact fluidized bed, which is stabilized by the buoyancy of the carrier particles and the back pressure at the water surface. The constant attachment of carrier particles to the lower fluidized bed and their buoyancy constantly pushes an equivalent amount of carrier material into the aerobic fluidized bed. The carrier particles briefly have additional contact with atmospheric oxygen. In the fluidized bed, a slow but constant movement of the growth carriers from bottom to top is created. In the fluidized bed to be purified wastewater and recycled activated sludge can be supplied. If a submersible aerator is used, the wastewater discharge can be carried out at least partially over it. Suspended and immobilized biomass consumes nitrate bound and dissolved oxygen within minutes, using the nutrients supplied to the wastewater. In this way, an anaerobic fluidized bed is increasingly formed from the anoxic upwards. Due to the adjusting environment conditions and the present in high density biomass biologically usable carbon compounds and microorganisms not adapted to this environment are hydrolyzed into low molecular weight compounds. Certain hydrolysis products are taken up by P-storing microorganisms and used for the Ba'jstoffweshsel. For this purpose, intracellularly stored polyphosphates are used as the energy source. This leads to an increase in the concentration of the dissolved phosphates in the fluidized bed zone.

The anaerobic medium conditions prevailing in the fluid bed mean elnon for the P-epelchierenden organisms Selective advantage. Furthermore, there is a conversion of organic nitrogen compounds into ammonium. Due to the flow movement in this stage suspended and immobilized Blomasso then enter the aerobic Wirbolbettzone. In this zone, the minimum residual acid content is 1.6 g / cm '. Due to the swirling forms on the The carrier is a thin, physiologically very active biofilm. By smashing larger Belebtechlammflocken

another effect is achieved which has a positive effect on the metabolic intensity.

In the aerobic fluidized bed zone carried a degradation of organic wastewater ingredients, a Nltrlflkatlon of ammonium and

an ellipticity of phosphate by P-splitting microorganisms. While the immobilized biomass with the carriers is im '. jaktor remains, leaves a portion of the suspended biomass with the treated wastewater through the reactor

Procedure. Part of this biomass is after separation in Nachklärbecken or as Toilstrom from the reactor drain the Reactor fed again via the fluidized bed. The discharge of the carrier is by a special arrangement of diving walls and

prevented by utilizing the relatively low specific gravity. In the arrangement of a Tauchstrahlbelüfters its liquid supply can take place from the reactor itself. Through this circulation through the immersion heater, it is possible to vary the residence tents in the reactor according to the load with wastewater.

A variant according to the invention consists in the separation of the reactor space through a dividing wall into two partial reactors,

wherein in each sub-reactor one or more baffles and a Intonslvbolüftersystem are arranged. The feed for wastewater to be treated flows into the fluidized bed zone of the first partial reactor. The feed for return sludge and a

Partial flow from the reactor effluent is introduced into the fluidized bed zone of both partial reactors. The sequence of the first part reactor

also leads to the fluidized bed zone of the second sub-reactor.

In the first part reactor closed-cell carrier material has a density of 0.4 to 0.95 g / cm ³ and a diameter

from 1 to 10mm, z. For example, sintered foam polystyrene flocks. In the second part reactor is open-pored

Carrier material having a density of 0.6 to 0.95 g / cm ³ and a diameter of 5 to 30mm. Particularly advantageous is the use

of PVC hollow cylindrical bodies (Raschlgringe), each with an open pore and / or open-cell foam body.

The advanced function of this embodiment is as follows: Due to the intensive aerator, aerated and carrier material from the surface in the lower part of the fluidized bed zone

promoted and swirled there. Part of the fluidized carrier passes under the anaerobic fluidized bed.

The floating and drifting from the upper anaerobic fluidized carrier form in surface near a direction

of the intensive aerator moving fluid bed. The rising bubbles pass through this fluidized bed. This is how it happens

Enrichment of oxygen, and the aerosol discharge is minimized. The wastewater to be cleaned, the return sludge and a partial flow of recycled medium from the expiry of the subsequent Reactor are fed to the anaerobic fluidized bed from above. At the passage of the step, a part becomes more particulate Retained wastewater ingredients. Using the carbon compounds contained in the waste water is fed Nitrate denitrified. Furthermore, a partial anaerobic hydrolysis and fermentation of organic substances, the ammonification

organic nitrogen and the inclusion of special nutrient substrates by a partially anaerobic hydrolysis and fermentation of organic substances, the ammonification by P-storing microorganisms. Part of the non-adapted to the milieu

Microorganisms of the activated sludge are selected and likewise anaerobically hydrolyzed. The released Carbon compounds can be used for denitrification. The first part reactor is relatively highly loaded with organic matter (BOD volume load greater than 2 kg / m ³ , d). By the Enrichment of various suspended biomass immobilized on support material in the form of a thin biofilm

there is a fast and extensive degradation of organic matter. Favoring effect thereby is that the relatively large

Activated sludge flakes are smashed through the fluidized bed into smaller, but more physiologically active fragments. It is noteworthy that in this stage already nitrifying bacteria settle on the carrier material. The extensive degradation of organic wastewater constituents, especially during peak loads, is the prerequisite

for the biochemical effects of the subsequent stage.

The material In the second part reactor is colonized by nitrifying bacteria and especially filtering unicellular microorganisms. The Cavities provide protection against excessive abrasion of the biomass. Accordingly, the fouling by the mechanical Stress in the fluidized bed and reversible submersible kept within limits. The density does not increase significantly. Due to the low BOD volume load, strong nitrification processes occur at this stage. The nitrate is in Partial streams fed to the anaerobic fluidized beds of the first and second stage and there denitrified to molecular nitrogen. The carrier material with the special microorganisms remains in the respective stage. Due to the special process control and the use of different, adapted to the desired biological processes Growers, the sludge synthesis rate will be well below the experience. It continues to come to a

increased digestion of biochemically stable organic substances. The proportion of P-storing microorganisms increases significantly and will thus cause a further P-elimination.

embodiments The invention is explained in more detail below with reference to four examples. Showing:

Fig. 1: reactor with submerged jet ventilation Fig. 2: reactor with compressed air ventilation Fig. 3: two-stage reactor Fig. 4: three-stage reactor.

example 1

Wastewater activated sludge mixture is supplied from the carrier material-free outlet 8 of the reactor according to the invention with a Tauchstrahlbelüfter 3 with pressure in the middle of the fluidized bed zone 2 of the reactor. The reactor contains granular carrier material with an average density of 0.45 g / cm ³ and an average diameter of 3 mm. The proportion of with carrier material

filled fluid bed zone 1 in the total reactor volume is 26%. In the fluidized bed zone about 30Vol .-% carrier material are included. Olo to both rare of rectangular, 3m high and 1.6m wide reactor arranged β ranging from 80cm above the reactor floor to 10cm above the water surface. They occupy the entire width of the reactor.

The feed 7 for wastewater to be treated flows into the fluidized bed zone. The expiration of the feed equivalent amount of wastewater via submersible walls 5, which prevent a discharge of carrier material. Part of the biomass is fed to the reactor via the inlet 7 after separation in a secondary clarifier.

example On the outer sides, along a 3m high and 1.5m wide reactor compressed air aerator 4 are arranged. In the ventilated Fluidized bed zone 2 comprises about 25% by volume of carrier material having a density of 0.4-0.6 g / cm ³ and a diameter

from 2 ~ 4mm. In the reactor, guide devices 6 are arranged on both sides over the entire length. They begin 1,50m over the dom

Reactor bottom and end 7cm above the water surface. The proportion of fluidized bed zone 1 forming in the middle

is 30%. The fluidized bed zone 1 is filled with carrier material. The inlet 7, the outlet 8 via Tauchwändo 5 and the

Feed of return sludge are formed analogously to Example 1. Due to the lateral entry of compressed air, a loop flow forms between the reactor wall and the fluidized bed wall.

which floating support material rips down again, so that this can accumulate under the fluidized bed 1.

It is possible to design the reactor according to requirements or local conditions in further embodiments. In a round reactor with an additional central tube, the fluidized bed zone forms depending on the arrangement of Ventilation device outside or inside out. Furthermore, the guide can preferably be arranged only on one side in a longitudinal reactor. The effect catfish

is in accordance with the height-width ratios analogous to the embodiments with two or more

Delineators. Example 3 Another embodiment of the invention describes one of two 4m high and 2m wide partial reactors (9,10)

existing reactor. Both also each have a fluidized bed zone 2 and a fluidized bed zone. 1

In the first part reactor are 40Vol .-% (bulk volume) sintered foam polystyrene with an average density of

0.5g / cm ³ and a diameter of 2-10mm.

By the arrangement of the guide 6, which begin 8cm above the water surface and at one third of the Reactor height end, it comes in each case to the formation of a slowly moving from bottom to top, compact Fluid Bed 1. The movement of the fluidized bed 1 is effected by the buoyancy of the specific light carriers. These are stored

at the bottom and flow back into the adjacent fluidized bed 2 after passage of the bed. The anaerobic fluidized bed 1 occupies about 10% by volume of the two partial reactors (9, 10). In both partial reactors (9,10) are still each a ventilation and

Circulating means arranged in the form of a reverse submersible 3. Through the nozzle of the radiator is pressurized water

Radiated via an axially centered guide tube 11 on a located on the bottom floor distributor device 12.

The upper edge of the funnel-shaped guide tube 11 is located 3 cm below the water level. In contrast to the first, in the second sub-reactor open-cell, foam-like carrier materials or a mixture of

foam-like and closed-cell carriers with larger cavities (eg raschigringartige plastic body) used. The density of the supports is 0.6-O, 95g / cm ³ , and the diameter preferably ranges between 5 to 20 mm.

The sequence of the first to the second partial reactor and the outlet 8 of the second Teilreaktqrs via submerged walls 5, the

prevent a carrier material decoration. The return of a partial flow from the Keaktorablauf 8 via a

Pump 13 in the fluidized bed zone 1 and in the two Tauchstrahlbelüfter third Example 4 In the first part reactor 14 of a reactor consisting of three partial reactors (14, 15, 16) there are 25-40 vn.

(Bulk volume) of a granulated, closed-cell, structured carrier material (sintered foam polystyrene) having a density of 0.35-0.95 g / cm ³ and a grain diameter of 2-10 mm. Each sub-reactor again has a ratio between width and height of at least 1: 2. The carrier material is soverwirbelt by centrally disposed Druckluftbelüfter 4 that forms a turbulent fluidized bed in the partial reactor 14.

The lateral arrangement of a guide 6 forms a compact, slowly moving from bottom to top Fluidized bed. The fluid bed zone 1 and its movement is effected by the buoyancy of the specific light carrier. The top End of the guide 6 protrudes over the water surface. The fluid bed zone takes up about 15% by volume of the first partial reactor 14

and GVol .-% of the total reactor.

The fluidized bed zone 1 are the wastewater to be purified, return sludge 17 and medium from the third part of the reactor 16th

fed. At this stage, anaerobic environment conditions develop. This has the following effects:

Denitrification of incorporated nitrate, anaerobic hydrolysis of high molecular weight organic substances into low molecular weight, Ammonification of organically bound nitrogen, uptake of low molecular weight nutrient substrates by P-storing Microorganisms (thereby promoting the growth of these microorganisms) and selection of organisms of the Activated sludge, which are not adapted to the anaerobic environment. The latter effect results in a reduction of the sludge synthesis. The first part reactor 14 is relatively highly loaded with organic matter. The BOD volume load here is more than 2kg

BODs / m ³ -d.

By the accumulation of various suspended suspended microorganisms immobilized on support material

over 70% of BOD ₆ mined. Favoring effect on the elimination rate that the relatively large

Slurry activated sludge flakes through the fluidized bed into smaller, but physiologically much more active fragments

become. On the surfaces of the carrier forms a thin, very active biofilm. It is noteworthy that already in this relatively highly loaded stage nitrifying bacteria settle.

The extensive degradation of organic wastewater constituents, especially during peak loads in the first Tellreaktcr 14, Ist

the precondition for biochromic effects in the following stages.

Partially purified wastewater and suspended biomass pass through a carrier-retaining drainage

Subsequently, in a second partial reactor 15. Oils immobilized biomass remains with the carriers in the first part reactor 14. Dienachfolgende stage, it takes about Vi of the total volume, is filled to 30 to 60Vol .-% (bulk volume) with a foam-like, open-pore carrier material. The diameter of the carrier is such that during the

Ventilation phase approximately the entire foam body is supplied with oxygen. Preferably, therefore, is the

average diameter less than 2cm. The specific gravity fluctuates during operation at 0.9 to 1.1 g / cm ¹ . On

The reason for the sufficient Oj offers are the foam body on the outer layers, but also inside

colonized mainly by aerobic or facultative aerobic microorganisms. Nitrifying bacteria also find optimal conditions in the relatively low-carbon but oxygen-enriched environment. There is therefore an intensive biological oxidation of ammonium to nitrate / nitrite in this stage. At the same time, there is a further reduction in BOD. By

P-splitting microorganisms are taken up in excess phosphate. The partly nitrified wastewater, largely bioremediated by bio-usable carbon compounds, and the suspended one Biomass then pass into a third partial reactor 16. The BOD volume load of this stage is below

0,3kg BOD / m'-d. Nitrlfizierende microorganisms find in this stage optimal living conditions during the

Denitrification is only partially possible due to the lack of carbon compounds. In the third partial reactor 16slnddaher also open porous, foam-like carrier (10-50 vol .-%) included. They differ

different from those of the precursor due to a larger average diameter. This is 3-4cm. This has the consequence that eichduring aeration forms an outer aerobic layer and set in the interior anaerobic-anoxic environment conditions mitentsprechenden microorganism groups. The annealed anoxic core occupies about 20% by volume of the carrier. In the pores of the margins, predominantly fixed ciliates settle. Through their cilia movement becomes one

Microturbulence generated, which cause a mass transfer from outside to inside and vice versa. This will get under

also particulate substances, in particular bacteria, in the anaerobic anoxic area of the carrier. Some of these substances are micro-bled into low molecular weight compounds in this environment. Some of the hydrolysis products are again used for microwave denitrification. This nitrate reduction also takes place when the surrounding environment with the carrier

Oxygen is enriched. In order to achieve a more denitrification, a part of the effluent from the third partial reactor 16 medium of

arranged in the first part reactor, highly enriched with carbons anaerobic fluidized bed zone 1 fed.

In order to achieve a simultaneous nitrification denitrification, separately controllable in the second and third part of the reactor Ventilation devices 4 arranged. They are alternately in predetermined zoom intervals and given time duration

put into operation. Vorzugswelse joins a ventilation phase of 10 to 20min a so long rest without

Oxygen input. The constant change between aerobic and anoxic environment conditions causes nitrifying bacteria

and denitrifiers alike in a sub-reactor.

The second partial reactor 15 is under certain load conditions to stimulate nitrification, a partial flow (approx.

20% by volume) of BOD-containing wastewater.

Of procedural importance is that again sedimentable in the second and third part of the reactor Make activated sludge flakes. The sludge synthesis rate is comparatively low. With the reactor according to the invention a number of advantages can be achieved. The wastewater to be treated is alternately aerobic and anaerobic conditions in a fluidized bed and a fluidized bed

exposed. All groups of microorganisms essential for wastewater treatment find the necessary in the reactor for them

Environmental conditions: Nitricants - sufficient oxygen to nitrify N compounds

P-eliminating - anaerobic-anoxic conditions for the elimination of low molecular weight compounds and aerobic microorganisms for P uptake from wastewater

Hydrolysis Bacteria - anaerobic anoxic conditions for the formation of low molecular weight organic substances due to a high biomass concentration

The invention ensures very intensive biotechnological processes. With low technological and equipment expenditure, effective C, P and N elimination is possible in the smallest space. The invention can thus be used advantageously economically, especially in smaller and medium-sized plants. A retrofitting beatehender plants is possible with low costs.

Claims (10)

1. A process for anaerobic-aerobic wastewater treatment with increased C, P and N Ellminlerung, characterized in that in a reactor contained Verwbarer carrier materials are passed through an unbelüfteto Fließbettzono and a vented fluidized bed zone in the circuit, wherein an automatic removal of carrier material and re-introduction into the fluidized bed zone by means of an intensive aerator plant and return sludge and / or a Tollotrom from the reactor effluent completely or partially and / or treated wastewater wholly or partly is introduced into the non-aerated fluidized bed zone. 2. Reactor for anaerobic-aerobic wastewater treatment with increased C-, P- and N-Elimlnierung, wherein in the reactor for the partial immobilization of biomass fluidizable carrier materials are included, characterized in that the reactor through one or more baffles in a ventilated by means of intensive aerator fluidized bed zone and an unvented fluidized bed zone is divided, wherein the guide walls from above the reactor bottom to above the water level, that the feed for wastewater, return sludge and / or a partial flow from the reactor effluent in the fluidized bed zone, in the reactor granular or lumpy support material of density 0 , 4 to 0.95 g / cm ³ and a diameter of 1 to 30 mm is included and a drain with support material retention is provided. 3. Reactor according to claim 2, characterized in that the Volurnenanteil of the fluidized bed zone in the total reactor volume is 10 to 40%. 4. Reactor according to claims 2 and 3, characterized in that the fluidized bed zone in the operating state contains 10-40 vol .-% carrier material. 5. Reactor according to claims 2 to 4, characterized in that the intensive aerator is arranged in the fluidized bed zone Tauchstrahlbelüfter. 6. Reactor according to claim 5, characterized in that the liquid supply of the Tauchstrahlbelüfters is connected to the outlet of the reactor. 7. Reactor according to claims 5 and 6, characterized in that axially axially below the mouth cross-section of Tauchstrahlbelüfters a guide tube is arranged, the horizontally extended upper edge is in the operating state below the water level. 8. Reactor according to claims 2 to 4, characterized in that the intensive aerator is arranged at the bottom of the WiiLielbettzone compressed air ventilation system. 9. Reactor according to claims 2 to 8, characterized in that the reactor space is divided by a partition wall, in each sub-reactor one or more baffles and an intensive aerator system are arranged, wherein in the first part reactor closed-cell carrier material of a density from 0.4 to 0, 95g / cm ³ and a diameter of 1 to 10 mm and the second part reactor open-pored carrier material having a density of 0.6 to 0.95 g / cm ³ and a diameter of 5 to 30 mm is included, that the inlet for wastewater in the flow zone the first part of the reactor and the inlet for return sludge and a partial flow from the reactor effluent in the fluidized bed zones of both partial reactors opens and the flow of the first part reactor feels in the fluidized bed zone of the second sub-reactor 10. Reactor according to claims 8 and 9, characterized in that the open-pore carrier material are PVC hollow cylinder body, each with an open pore and / or foam body.