DE10301858A1 - Small scale sewage treatment plant is in a circular structure for sewage to flow outwards from the center bioreactor, into the denitrification/nitrification stage and the sedimentation zone to the cleaned water outflow - Google Patents

Abstract

The small-scale sewage treatment plant has a bioreactor (6) with a solid bed (38) to carry colonies of micro-organisms to give an anaerobic action. The small-scale sewage treatment plant has a bioreactor (6) with a solid bed (38) to carry colonies of micro-organisms to give an anaerobic action. It has a denitrification and/or nitrification stage (8), a sewage inflow (2), a sedimentation zone (10) and a cleaned water outflow (14). A system (12,24) removes solid materials. The denitrification/nitrification stage is in a ring structure around the center bioreactor. The sedimentation zone, with the cleaned water outflow, is around the denitrification/nitrification stage, so that the sewage flows outwards from the center bioreactor, through the denitrification/nitrification stage and the sedimentation zone. The flow links are through overflows (66,68).

Description

The invention relates to a biological wastewater treatment plant according to the generic term of claim 1.

In biological wastewater treatment, microorganisms convert the organically usable ingredients of the wastewater to be processed into cell material or gases, such as CO ₂ , methane, hydrogen sulfide and others. Depending on the procedure, a distinction is made between aerobic and anaerobic processes, whereby the more controllable aerobic processes are generally used in municipal sewage treatment plants. Especially in sparsely populated regions, it is often not worthwhile to operate a central sewage treatment plant, so that decentralized solutions are sought. Such decentralized wastewater treatment can be carried out, for example, by domestic wastewater treatment plants or local wastewater treatment plants. Particularly in recent years, great progress has been made in the design of such small wastewater treatment plants.

At www.3kplus.de there is a section operated small sewage treatment plant described with SBR technology (Sequencing Batch Reactor). at such a discontinuously operated small wastewater treatment plant the wastewater to be treated is treated in a fixed bed reactor. This fixed bed reactor has a fixed bed block with a large specific Surface, the as a growing area for a microorganism population acts. This means, on the surface of the solid a biofilm forms in which a multitude of different Bacteria live side by side in a very small space can. These bacteria interact with the one to be treated Waste water, with the known method of this biological Cleaning is preceded by a mechanical cleaning stage. By a pressure ventilation becomes the container content periodically circulated from activated sludge and waste water and the microorganisms with that for the aerobic cleaning process necessary Oxygen supplied.

Depending on the application, this can be done aerobic biological cleaning yet another cleaning stage, connect nitrification and denitrification, for example is switched between anoxic and aerobic phases during operation.

After this nitrification and denitrification phase this is followed by sedimentation of the solid ingredients (activated sludge), so that the sludge phase is separated from a clear water phase. The clear water phase and the remaining excess sludge become after deducted from the sedimentation and optionally further processed.

The disadvantage of this solution is that the batch operation initially requires a considerable procedural effort and the Another big one Buffer must be connected upstream in order to operate batchwise enable.

In the specialist book on wastewater technology, Hosang / Bischof, 11th edition, Teubner Verlag, 1998 are other small sewage treatment plants described, in addition to discontinuously operated small sewage treatment plants systems are also described in which - similar to a municipal Kläranlage- several stages, for example a preliminary clarification, an anaerobic biological Treatment and aerobic biological treatment switched in succession are, each using its own reactors. such solutions require a considerable expenditure in terms of device technology and Space requirements.

In contrast, the invention is the Task based on a small wastewater treatment plant to create continuous operation with compact dimensions allows.

This task is carried out by a biological small sewage treatment plant solved with the features of claim 1.

In the solution according to the invention an essentially anaerobically operated bioreactor is arranged centrally and is encompassed by a nitrification / denitrification stage and a sedimentation room. The wastewater to be treated flows in the solution according to the invention from the centrally located anaerobic bioreactor approximately in the radial direction {seen in plan view) outwards into another bioreactor (Nitrification / denitrification stage) and finally in the sedimentation room where the separation between the excess sludge and the clear water phase takes place. The two phases will then end deducted this sedimentation space. Through this flow of a central feed to the anaerobic bioreactor, the denitrification / nitrification stage and the sedimentation room to the outside, the entire system can be extremely compact be formed, the connection of the individual stages with minimal effort without complex piping systems can.

In a preferred solution the The connection between the individual stages (bioreactor Denitrification / nitrification level and sedimentation room) each by means of an overflow. That is, no pumps or the like are required to the wastewater flow within the small wastewater treatment plant maintain. It is only necessary through appropriate Flow guidance, for example by providing a feed pump a predetermined waste water volume flow ensure in the area of the inlet. The further wastewater flow is determined by appropriate design of the overflows without using no energy fed from outside must become.

The elimination performance of the small wastewater treatment plant can be improve if part of that in the denitrification / nitrification stage and treated wastewater in the sedimentation room to the upstream Stage is returned.

In the solution according to the invention it is particularly advantageous if the anaerobic bioreactor has an acidification stage is connected upstream, in the control and stabilization of acidification and Hydrolysis fed to microorganisms become.

The acidification stage is preferably coaxial trained to and operated with the anaerobic bioreactor also about an overflow connected. It is preferred if this overflow in the bottom area of the anaerobic bioreactor opens.

The supply of the wastewater to be treated is particularly easy when the acidification level or the bioreactor a wastewater inlet is connected upstream, which has an overflow tank, the overflow of which also in the next floor Level, for example the acidification level empties.

Such a wastewater inlet can a mixing container have arranged in the overflow tank is and this over an overflow fed.

In the aerobic stage (denitrification / nitrification) is preferably an annular one Fumigation unit for feeding from that for the nitrification required oxygen is provided.

This level is at a preferred level embodiment through a container with three sub-rooms trained the zigzag Flows through from inside to outside become. The subspaces are designed so that a backflow to the upstream Partial space possible is and thus the performance of the sewage treatment plant is improved.

In a particularly preferred embodiment the anaerobically operated bioreactor has two axially one above the other Reactor Facilities, between which a support layer for microorganisms is trained. Forms on this carrier layer a biofilm that contains the necessary for anaerobic degradation Contains microorganisms (Immobilization).

This carrier layer can, for example from a catalytically active ceramic and / or from one with activated carbon coated carrier material consist.

In a variant of the invention there is the carrier layer made of alternating ceramic and the one coated with activated carbon Support material the cascade flowed through successively become.

In one embodiment of the invention the bioreactor can be flared towards the bottom, so that a lower flow velocity in the bottom area than in the one above Area is present. This lower flow rate of the wastewater supports the Sedimentation of solid particles in the bioreactor.

With such a solution it is preferred if the waste water in the area of the bottom of the bioreactor supplied is, this bottom is then concavely curved, so that the wastewater is swirled. The floor then falls to its edge areas down again, so that a space for the sediment to deposit Provided is.

In a preferred embodiment of the The bioreactor and the aerobic stage in the axial direction have invention seen a substantially round cross-section, during the sedimentation space encompassing these two stages has a rectangular outer circumference having.

The overflows to connect individuals Levels through an overflow pipe be formed having a funnel-shaped inlet and preferably also a funnel-shaped Has outlet that opens in the bottom region of the downstream container.

It has proven to be particularly advantageous if a mixed culture is used for the biological treatment of the waste water, which contains a proportion of photosynthetically active microorganisms and luminous bacteria. Such microorganisms are for example in the DE 101 49 447 A1 described by the applicant, so that reference can be made to the disclosure in this regard for the sake of simplicity.

Other advantageous further training the invention are the subject of further dependent claims.

The following are preferred embodiments the invention with reference to schematic drawings. Show it:

1 a cross section through a biological small sewage treatment plant according to the invention and

2 a detailed view of a bioreactor of another embodiment of a small wastewater treatment plant.

1 shows a section through a small sewage treatment plant 1 , in which domestic or industrial wastewater is treated and which is designed for a capacity of 50 to 1000 equivalent inhabitants. The small wastewater treatment plant 1 basically consists of a wastewater inlet 2 , an acidification level 4 , an anaerobically operated bioreactor 6 , a ring-shaped denitrification / nitrification stage 8th , a sedimentation space encompassing the above-mentioned steps in a top view 10 and a mud vent 12 and a clear water drain 14 ,

According to 1 are the wastewater inlet 2 , the acidification level 4 and the anaerobically operated bioreactor 6 coaxial to a central axis 16 one above the other in the center of the system 1 arranged. The denitrification / nitrification stage 8th and the sedimentation room 12 enclose the bioreactor 6 , where in the top view the inlet 2 , the acidification level 4 and the bioreactor 6 and the denitrification / nitrification stage 8th each have an approximately circular cross section, while the top view of the sedimentation space preferably has a rectangular cross section. However, it is also possible the sedimentation room 10 to be circular or square. The small wastewater treatment plant is preferably made of stainless steel.

The domestic or industrial wastewater to be cleaned arrives via a channel into a wastewater collection shaft, not shown, which serves to buffer volume surges and as a pump template. A pump installed in this waste water collection shaft, which can optionally be preceded by a cutting device for crushing coarse waste water constituents, then conveys the water to the 1 shown wastewater inlet 2 , For special requirements it is possible to use the small sewage treatment plant described in more detail below 1 add a mechanical treatment stage to reduce the solids content in the wastewater.

The sewage inlet 2 has a central inlet pipe 18 through which the wastewater is sent to a mixing tank 20 is fed. The inlet pipe 18 opens just above the bottom of the mixing container 20 , so that the wastewater supplied flows into the mixing tank 20 is redirected and swirled strongly. This in 1 indicated turbulence leads to the fact that sludge carried along with the wastewater is already partially in the radially outer regions of the mixing container 20 can discontinue. This turbulence can be caused by the inclination of the inlet pipe mouth 18 with reference to the central axis 16 get supported.

The mixing tank 20 is in an overflow tank 22 arranged so that from the mixing container 20 overflowing waste water in the overflow tank 22 flows. Its capacity is designed so that an even loading of the bioreactor 6 regardless of the pump delivery rate. Part of the sludge carried also settles in the overflow tank 22 off, this sludge and that in the mixing tank 20 Any sludge present can be removed via a sludge discharge, not shown. The overflow tank 22 also has a return 24 , through which excess wastewater can be returned to the collecting shaft.

The overflow tank 22 is over a partition from the acidification stage 4 Cut. That in the overflow tank 22 pre-treated wastewater is treated with an overflow pipe 24 in the below the overflow tank 22 trained acidification level 4 directed. The overflow pipe 24 has an overflow tank level at the WSP water level 22 arranged funnel-shaped inlet 26 and a funnel-shaped outlet 28 that in the area of the bottom of the acidification level 4 empties. These funnel-shaped inlets and outlets 26 . 28 can each have v-shaped incisions 30 be provided, through which an inlet or outlet cross-section is formed which is dependent on the height of the water level.

The acidification level 4 a mixed macrobiotic culture is supplied, which contains a proportion of photosynthetically active microorganisms and luminous bacteria or light-emitting microorganisms with a similar effect. The interplay between the photosynthetically active microorganisms and the luminous bacteria means that the photosynthetically active microorganisms are stimulated to photosynthesis by the emitted light. The microorganisms carry out photosynthesis with hydrogen sulfide and water as starting material and release sulfur or oxygen. They can also bind nitrogen and phosphate and break down organic and inorganic matter. With regard to the concrete composition of this microbiotic mixed culture, for the sake of simplicity, reference is made to the one mentioned at the beginning DE 101 49 447 A1 or the DE 100 62 812 A1 referred to the applicant. The one in the bioreactor 6 Microorganisms used correspond to those that have been added to the acidification stage.

At the in 4 The illustrated embodiment is the overflow pipe 24 in the edge area, ie at a distance from the central axis 16 of the overflow tank 22 or the acidification stage formed coaxially to this 4 arranged.

In the acidification stage 4 is another overflow pipe 32 arranged, via which the acidified and hydrolyzed wastewater to the bioreactor 6 is fed. This overflow pipe 32 is coaxial to the central axis 16 arranged and has practically the same basic structure as the overflow pipe 26 , The funnel-shaped inlet 26 is at the level of the water level WSP of the acidification level 4 arranged and the funnel-shaped outlet 28 opens into the bottom area of the bioreactor 6 , That is, both the acidification level 4 as well as the bioreactor 6 are flowed through from below, ie from the bottom, up to their respective overflow.

How 1 can be removed, the bioreactor has 6 two reactor rooms one above the other in the axial direction 34 . 36 , between which a carrier layer described in more detail below 38 is arranged for microorganisms. The lower reactor room 34 delimiting reactor jacket is conical from its bottom to the support layer 38 tapered towards. By reducing the flow cross-section within the bioreactor 6 to the carrier layer 38 down, there is a lower flow rate in the bottom of the reactor than in the area of the support layer 38 so that the settling of excess sludge in the floor area is supported. This settling is further improved in the solution according to the invention by a special floor design. This is the bottom of the bioreactor 6 in the mouth area of the funnel-shaped outlet 28 with a concave swirl section 42 trained in the outlet 28 dips. This swirling section bulging towards its edge sections 42 then goes back to the reactor jacket 40 down falling bottom edge 44 through which a sedimentation space for the anaerobic sludge is formed. In the area of this bottom edge 44 is then the in 1 indicated deduction 46 intended for the anaerobic sludge.

That through the overflow pipe 32 in the bioreactor 6 entering wastewater is through the concave swirl section 42 swirls, the sludge settling preferably in the edge sections of the reactor and at the bottom edge 44 collects. The wastewater flows up to the carrier layer 38 , This serves as a growth body for the microorganisms used and accordingly has the largest possible specific surface. On this carrier layer 38 a biofilm forms through which the microorganisms used are immobilized.

At the in 1 illustrated embodiment consists of the support layer practically forming a fixed bed 38 made of porous PU mats, which are coated with activated carbon or another suitable carrier material. The anaerobic microorganisms immobilized in the biofilm break down the organic ingredients by mechanization according to the known processes. In other words, in the sewage treatment plant according to 1 becomes the acetogenic phase (acidification) essentially in the acidification stage 4 and the methanogenic phase essentially in the bioreactor 6 carried out.

After flowing through the fixed bed (carrier layer 38 ) the wastewater enters the reactor room at the top 36 , the peripheral walls of which are also covered with carrier material 46 is lined to form a biofilm and to immobilize microorganisms. The resulting biogas is then fed into an 1 indicated gas membrane 48 from the small wastewater treatment plant 1 deducted and used for further use.

Due to the photocatalytic surface of the growth body (carrier layer 38 , Carrier material 46 ) anoxygenic photosynthesis occurs very quickly, so that the organic components of the wastewater can be broken down quickly.

The microorganisms grow relatively quickly during the treatment of the wastewater through the carrier layer 38 and the carrier material 46 formed growth areas. The flow rate in the reactor is set so that the excess biomass is released and the excess sludge is removed by the shear stresses generated in the biofilm during flow - this prevents clogging and clogging of the growth areas.

The reactor room 36 has an overflow through which the wastewater after the anaerobic biodegradation of organic components into a further biodegradation stage - the denitrification / nitrification stage 8th overflows. This denitrification / nitrification stage - hereinafter referred to as the D / N stage - is implemented by a container which is formed by two internal partition walls 50 . 52 in three ring spaces 54 . 56 . 58 is divided. The outer jacket 60 the D / N stage is conical and tapers to the bottom of the sewage treatment plant 4 (down in 1 ) there. In the middle annulus 56 becomes a ring ventilation 62 provided so that this room can be ventilated. This can be omitted under special operating conditions. The required compressed air is generated by a small compressor.

The wastewater flows out of the reactor room 36 over the overflow into the internal annulus 54 and flows through it from top to bottom. The wastewater then enters the tapered floor space 64 the D / N stage and from there enters the floor space 64 open, ventilated middle annulus 56 on. In this annulus 56 Waste water is then nitrified, ie there is microbial oxidation of ammonium to nitrite and nitrate.

The wastewater flows through the middle annulus 56 from bottom to top and then passes through an overflow 66 in the outer ring space 58 , From this annulus 46 becomes a partial flow over another overflow 68 branched off into the sedimentation space, while the remaining portion lies within the outer ring space 58 down back to the floor space 64 flows. The floor space 64 is via a backflow opening 70 with the reactor room below 34 connected so that part of it is in the floor space 64 waste water again to the anaerobically operated bioreactor 6 is returned while another part, like with the arrows in 1 is shown again in the annulus 56 flows back and is nitrified there.

In the inner annulus 54 denitrification takes place, ie a reduction of the nitrate to gaseous nitrogen. As mentioned above, the wastewater can pass through the anaerobically operated stage as well as the aerobically operated stage several times with the upstream denitrification, so that the efficiency of the plant can be significantly improved. To adapt to different loads of the wastewater, it can be advantageous to control the cross-sections that determine the backflow via actuating devices.

That through the overflow 68 effluent then flows into the sedimentation room 10 by a partition 72 in two sub-rooms 74 . 76 is divided. The wastewater flows along the inner part of the room 74 downwards, is deflected in the floor area and then flows in the sub-area 76 up to the clear water drain 14 out. The sedimentation room 10 has a comparatively large cross-section, so that there are low flow velocities that support the settling of the excess sludge. Due to the rectangular shape of the sedimentation chamber in the top view 10 and the related big cross sections, the settling of the excess sludge is further improved. The excess sludge is then drained off 12 withdrawn via a suction pipe or the like, for example, and the clear water flows through the clear water outlet 14 from. This clear water drain 14 is designed with suitable retention devices that can be used to retain the solids still contained in the wastewater.

The small sewage treatment plant described above is characterized by an extremely compact structure, the elimination performance being achieved by the anaerobic preliminary stage (bioreactor 6 ) and the aerobic aftertreatment (nitrification) is optimized. Acidification in the acidification stage 4 is controlled by the addition of the microorganisms so that little or no hydrogen sulfide and other undesirable gases are produced. The system is also characterized by minimal energy consumption, since only the pump for supplying the wastewater and the compressor for ventilation are required to circulate the material flows. No pumps are required within the small sewage treatment plant to convey the wastewater between the individual stages. The process according to the invention results in comparatively little and more easily settable excess sludge which can be easily removed from the small sewage treatment plant.

In 2 is a further possibility for the formation of growth areas by means of the carrier material 38 educated. In this variant, the carrier material is made 38 alternately made of a large-pore ceramic material, each of which has a layer with a suitable catalyst, for example a PU carrier material coated with activated carbon 72 followed. Several of these layers can be provided side by side, the catalytically active ceramic preferably being made of titanium dioxide and having a pore diameter of approximately 20 mm. The PU carrier material is comparatively small-pored and has a pore diameter of 2 mm. The individual layers 70 . 72 are in the in 2 flows through one another in cascade form, so that an extremely large growth area is provided for the formation of a biofilm.

The flow is through the ceramic layer 70 stabilized, while the biofilm preferably forms on the next layer (PU carrier material / activated carbon), which is less prone to clogging due to the stabilized flow.

A small sewage treatment plant is disclosed with an anaerobically operated reactor, a denitrification / nitrification stage and a sedimentation room, the anaerobic reactor being arranged in the center, the denitrification / nitrification stage and the sedimentation room the anaerobic reactor approximately circular reach around, so that the aforementioned steps in the radial direction of Flows through inside.

1

wastewater treatment plant

2

waste water supply

4

acidification

6

bioreactor (Anaerobic)

8th

Denitrification / nitrification

10

sedimentation

12

sludge removal

14

Clear water drain

16

central axis

18

supply pipe

20

mixing tank

22

Overflow tank

24

Overflow pipe

26

inlet

28

outlet

30

incision

32

Overflow pipe

34

reactor chamber

36

reactor chamber

38

backing

40

reactor shell

42

the turbulence

44

bottom edge

46

support material

48

diaphragm

50

partition wall

52

partition wall

54

annulus

56

annulus

58

annulus

60

sheath

62

ring ventilation

64

floor space

66

overflow

68

overflow

70

return flow

72

partition wall

74

subspace

76

subspace

78

ceramics

80

PU backing

Claims (18)

Biological small wastewater treatment plant with an essentially anaerobically operated bioreactor ( 6 ) with a fixed bed populated by microorganisms ( 38 ), a denitrification and / or nitrification stage ( 8th ), a wastewater inlet ( 2 ), a sedimentation room ( 10 ) and a clear water drain ( 14 ) and a solids discharge ( 12 . 24 ), characterized in that the nitrification / denitrification stage ( 8th ) the centrally located bioreactor ( 6 ) encircles in a ring and that with the clear water drain ( 14 ) provided sedimentation room ( 10 ) the denitrification ons and nitrification level ( 8th ) so that the wastewater from the central bioreactor ( 6 ) outwards through the denitrification and nitrification stage ( 8th ) and the sedimentation room ( 10 ) is performed. Small sewage treatment plant according to claim 1, wherein the connection between the bioreactor ( 6 ), the denitrification and nitrification stage ( 8th ) and the sedimentation room ( 10 ) each with an overflow ( 66 . 68 ) he follows. Small sewage treatment plant according to claim 1 or 2, wherein a subset of the nitrified waste water via a return ( 70 ) to the bioreactor ( 6 ) is traceable. Small sewage treatment plant according to one of the preceding claims, wherein the bioreactor ( 6 ) an acidification level ( 4 ) is connected upstream, the microorganisms can be supplied. Small sewage treatment plant according to claim 4, wherein the wastewater inlet ( 2 ) an overflow tank ( 22 ), whose overflow, preferably on the bottom side, in the acidification stage ( 4 ) flows out. Small sewage treatment plant according to claim 5, wherein the overflow tank ( 22 ) a mixing container ( 20 ) is connected upstream, which in turn overflows with the overflow tank ( 24 ) is connected and in which an inlet pipe ( 18 ) opens on the bottom. Small sewage treatment plant according to claim 6, wherein the overflow tank ( 22 ) a mixing container ( 20 ) is connected upstream, which overflows with the overflow tank ( 22 ) is connected and in which the inlet pipe ( 18 ) opens on the bottom. Small wastewater treatment plant according to one of the preceding claims, the waste water inlet ( 2 ) is fed by a pump. Small wastewater treatment plant according to one of the preceding claims, the denitrification and nitrification stage ( 8th ) a, preferably ring-shaped, fumigation unit ( 62 } Has. Small wastewater treatment plant according to one of the preceding claims, the denitrification and nitrification stage ( 8th ) in three connected subspaces ( 54 . 56 . 58 ) is subdivided, with an internal subspace ( 54 ) from top to bottom, a middle section ( 56 ) from bottom to top and an outer subspace ( 58 ) flows essentially from top to bottom, and wherein a bottom-side return of a partial wastewater stream from the outer subspace ( 58 ) in the middle section ( 56 ) is provided. Small sewage treatment plant according to one of the preceding claims, wherein the bioreactor ( 6 ) two reactor rooms one above the other in the axial direction ( 34 . 36 ), between which a carrier layer ( 38 ) is arranged for microorganisms. Small wastewater treatment plant according to claim 11, wherein the carrier layer ( 38 ) several partial layers made of catalytically active ceramic ( 78 ) and with an absorbent or catalytically active material, for example a carrier material coated with activated carbon ( 80 ), which are arranged alternately in succession. Small sewage treatment plant according to claim 12, wherein the individual layers ( 78 . 80 ) are flowed through one after the other. Small sewage treatment plant according to one of the claims 11 to 13 , which is below the carrier layer ( 38 ) trained reactor room ( 34 ) is extended towards its bottom. Small wastewater treatment plant according to claims 5 and 14, wherein a bottom section ( 42 ) of the bioreactor ( 6 ) in the mouth area of the overflow ( 32 ) is concavely curved and a bottom edge sloping towards the edge of the concave area ( 44 ) connects. Small sewage treatment plant according to one of the preceding claims, wherein the bioreactor ( 6 ) and the denitrification and nitrification stage ( 8th ) seen in the axial direction a round and the outside sedimentation room ( 10 ) have a rectangular cross-section. Small sewage treatment plant according to one of Claims 1, 6, 7 or 10, the overflow ( 24 . 32 ) an overflow pipe with a funnel-shaped inlet ( 26 ) and a preferably funnel-shaped outlet ( 28 ) that opens into the bottom area of the downstream container. wastewater treatment plant according to one of the preceding claims, with a macrobiotic mixture consisting of a portion of photosynthetic and light emitting Microorganisms.