JPH10277578A - Fixed bed reactor for purifying waste water and operation of fixed bed reactor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize the contraction of the structural height of a fixed bed reactor and the reduction of washing cost and to uniformly distribute active biomass by upwardly extending the wall part of a reactor housing in a vertical direction from a floor part and positioning the end part of the wall part to the lower part of a feed means. SOLUTION: In a fixed bed reactor consisting of a housing 1, an upper cover 2 and a lower closure part 3, a floor part 4 is disposed in the lower region of the housing 1 and a supply part 5 for water to be purified is opened under the floor part 4. Supplied water is upwardly ejected from nozzles 6 formed on the floor part 4 in one row in a state uniformly distributed over the entire surface of the floor part 4. The water ejected and supplied at this time is allowed to flow through the region of a reactor 8 from a support bed 9 composed of a coarse granular substance (e.g.; gravel) and air is supplied from an air lift pump 11 to purify water to be purified by activated bacteria (biomass) and the obtained clarified water is taken out of an outflow port 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention comprises a reactor housing, in which a fixed bed of carrier particles coated with biofilm is present, wherein the purified bed flows through the fixed bed. A fixed-bed reactor (F) for purifying wastewater, which is provided with means for supplying and discharging water and feed means for aerating and circulating carrier particles in the fixed bed.
estbettreaktor) and a method for operating this fixed bed reactor.

[0002]

BACKGROUND OF THE INVENTION Fixed-bed reactors are used for the biological purification of all kinds of wastewater containing organic substances,
So-called "biofilms" consist of microorganisms that live on the surface of the carrier particles and stick to others. Such a fixed-bed reactor and the method technology therefor are used differently from the method using suspended biomass (so-called activated sludge method). In this case, the microorganisms existing on the surface of the particles decompose the wastewater contents.

[0003] In the purification of biological wastewater in fixed-bed reactors, in particular, the absorption of nutrients and of the culture medium and of the concomitant material replacement on the surface of the particles of the fixed bed results in a corresponding change. Then, biofilm (or biomass) grows, and this biofilm (or biomass) causes flocculation of the fixed bed in a short period of time. Therefore, the biomass that accumulates in the fixed bed reactor must be flushed from the fixed bed. This flushing is generally performed by discontinuous and intermittent cleaning using air or water or a combination of air and water.
The disadvantage here is the economics for the equipment necessary for washing, including the wash water storage and the sludge water storage, and for the containers and sedimentation basins for the equipment required for separating the sludge from the sludge water. Is a large expenditure. Such a facility and a method in which a sedimentary layer on which microorganisms grow are used for biological purification are described in the company report "Abwasserreinigung-Reststoffaufbereitung" (wastewater purification-residue preparation) of the applicant. It is known. In this document, a sediment layer consisting of particles with a diameter of 1 to 10 mm is used for the purification of wastewater. A further disadvantage here is that, as in other similar devices, the biomass required for the purification of the wastewater grows and increases in the region of the wastewater inlet, i.e. in the region where the substance concentration is highest,
On the other hand, in the remaining area, especially in the area above the reactor vessel, the biomass is significantly lower due to lack of "nutrition". Thus, when the action on the wastewater to be purified reaches a peak, despite the reactor vessel being set to a sufficient size,-in normal operation-in the reactor area where only a small action takes place. The resolution is reduced due to the lack of biomass.

[0004] To eliminate these disadvantages, the magazine "Che
mie Technik "3/95 paper" Nitrifikation und
The Denitrifikation im Dynasand-Filter "provides an air pump that operates on the principle of pumping by air. In this case, the housing of the reactor vessel is formed cylindrical over approximately half to two-thirds of the vessel length. And in the area below the vessel, conically terminating at the point, the air pump described above terminates just above the point of the cone, which is itself configured as a sand filter. The reactor is filled with carrier particles in the form of sand particles, which are surrounded by a biofilm.
The known art from the article mentioned in US Pat. No./95 satisfies the features of the preamble of claim 1 of the preamble. This fixed bed reactor allows for continuous washing and purification of the contaminated water. The air pump also allows for some stratification of the biomass present above the sand particles of the fixed bed reactor from below to above and from above to below. The movement of the water in the air pump and thus the entrainment of the particles is effected in a known manner by the supplied compressed air. The disadvantage here is that half of the total structural height of the reactor vessel to a maximum of 2 /
Only three are utilized for biological degradation by fixed beds. This is because the conical lower region of the reactor vessel is not utilized for biological degradation due to lack of ventilation and water supply. The required structural height is correspondingly subject to a large outlay on equipment. Furthermore, a disadvantage of this known technique is that a reactor of a particularly suitable construction and having a central air pump must be provided. This requires special equipment. Due to location considerations, only reactors of small structural height can often be provided, which may make it impossible to use reactors exceeding a certain height dimension. For other uses of such fixed beds, see the above-mentioned magazine "Chemie Technik"
From the paper published on 3/95, it is possible to know further the removal of the suspension and the residual nitriding treatment.

Another disadvantage is that in this known technique the ventilation takes place above the funnel-shaped water supply. The sand underneath flows to the air lift pump, but does not help aerobic biological wastewater purification.

[0006]

SUMMARY OF THE INVENTION The object underlying the present invention with respect to the above-mentioned prior art is to achieve a reduction in the height of the fixed-bed reactor and a reduction in the cost for cleaning, and a reactor for active biomass. The goal is to achieve the best possible uniform distribution throughout the container.

[0007]

SUMMARY OF THE INVENTION According to the present invention, there is provided, in accordance with the present invention, a substantially flat and horizontal direction for introducing purified water into a reactor housing in a region below the reactor housing. A fixed floor is placed on the floor, the wall of the reactor housing is vertically oriented upward from the floor, and feeding means is provided. And the edge is located just above the floor.

Thus, the above-mentioned magazine "Chemie Tech
Compared to the technique known from the article published on Mar. nik 3/95, almost the entire length of the reactor vessel is filled with an active fixed bed, so that the structural height concerned is optimally used for wastewater purification. By omitting the installation of the lower conical part (hopper) according to the known technique described above according to the invention, it is furthermore possible to purify the fixed bed present above the bottom in its entire cross section. In addition, the advantage is obtained that the water flows through and the ventilation is uniform, and the device according to the invention can be retrofitted in a fixed-bed reactor that is already in operation. The housing of the floor reactor is generally cylindrical in cross-section and may be formed in some cases polygonal, with the bottom surface being the same as the cross-section in other areas of the reactor housing. Subsequent installation in a fixed-bed reactor is possible: if a later-installed bioreactor requires further installation, the floor is formed, and the feeding means is constructed in accordance with the invention. In this connection, it is particularly important and advantageous that the invention according to claim 3 allows the floor or horizontal cross section of the fixed-bed reactor housing to have different dimensions. The suction of the circulating device (pump) is arranged at a small distance above the floor or above the optional support layer (claim). The fixed bed material present therein, which is biologically highly enriched for the reasons mentioned at the outset, together with the supplied wastewater, flows through the tubes of such pumps. Through the fixed-bed reactor, it is directed upwards to a washing device provided therein, where the particulate fixed-bed material is released from the loose biomass. For other constructions, refer to the description in the embodiment of the invention and claim 12. According to the present invention, the circulating device has a lower end in a lower region of an active fixed bed. In other words, since it is arranged just above the floor or the support layer, this circulation device is different from the arrangement known from the article published in the above-mentioned magazine "Chemie Technik" 3/95, The reactor is trapped in its active area and sent upwards, and the water and air supply purified according to the invention is very well adaptable to the requirements of biological purification. Claims in the claims Means means and features according to the preamble of,
Work synergistically to solve the problem and achieve the benefits described above.

According to claim 2, an advantageous embodiment of the feed means is a water / solids pump, for example a so-called air pump, which works according to the principle of pumping by air. However, a water jet pump can also be used. The use of such a style of pump
Advantageously, they work with pressurized air or water, so that the risk of collision of the carrier particles surrounded by the biomass with the mechanical pump part and of dissociation of the biomass from the particles is correspondingly reduced.

[0010] Since the floor is flat and horizontal, any number of such pumps can be juxtaposed to each other (see claim 3 in this regard). No separate cone or hopper is required for each of the air lift pumps, as in the known art described above, and no intermediate wall is required between these air lift pumps. On the contrary, the pumps required according to the invention, in particular the air pump, can be provided in a common reactor housing with a cross section corresponding to the reactor.

[0011] The invention further relates to a method for operating a fixed-bed reactor constructed according to the invention. This method can be applied in an advantageous manner to the invention. Regarding this method, refer to claims 8 to 12 of the claims. DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail with reference to the embodiments of the invention illustrated in the drawings illustrated below.

1 and 2 show an embodiment of a fixed-bed reactor according to the invention comprising a housing 1, an upper cover 2 and a lower closure 3. FIG. No covering for the upper closure of this reactor is provided in conventional constructions. This shroud is only necessary in the case of the occasionally required exhaust treatment. Furthermore, a floor 4 is provided in the area below the reactor housing, in which a supply 5 for water to be purified is provided.
Is open. The supplied water is evenly distributed over the entire surface of the floor 4 by means of a row of nozzles 6 or a similar type of distribution device (see FIG. 2 in this regard) and the arrows 7 Sent upward in the direction. Thereby, the supplied water reaches the area of the fixed bed reactor 8 existing on the floor 4 and existing above.
In some cases, a support layer 9 is further provided between the fixed-bed reactor 8 and the floor 4, and this support layer is made of a coarse-grained substance (for example, gravel). The material of the fixed-bed reactor consists of a granular material, for example expanded clay (Blaehton) whose surface is surrounded by microorganisms (biofilm or biomass). This carrier material with biomass, also called growth, has a diameter of 1 to 10 mm and forms a fixed bed reactor 8 in the form of a loose bulk material. Since the bulk material is similar to a filter, the bulk material is also referred to as a biofilm.

FIG. 2 in particular shows that the floor 4 is substantially flat and even horizontal. Reactor housing 1
Extend vertically upward from the edge of the floor 4, so that the floor surface corresponds to the horizontal cross section of the reactor housing 1. In particular, the reactor housing 1 has a floor 4
And the upper cover 2 and the lower floor 3 together form a cylindrical body. However, the reactor housing may have other cross-sections different from the circular horizontal cross-section.

In addition, air is supplied by the nozzles 6 of the floor 4 or by other nozzles provided therein.
Is introduced into the fixed bed 8 in the direction of. This supply of air is necessary for the active activity of microorganisms. However, this supply of air does not have to take place via the floor provided for the water supply. It is possible to provide other air supply means for the supply of this air, which must of course be below the fixed-bed reactor 8.

The water to be purified flows upward in the fixed-bed reactor 8 and is discharged from the outlet 10 in a purified state. See FIG. 3 and the description relating to this figure for details. In the case of this embodiment,
At least one air pump 11 extends downwardly from the upper region of the reactor housing, the lower end 12 of which is open at a small distance from the floor 4 and the support layer 9. I have. Instead of an air pump, it is also possible to provide other pumps, in particular pumps that do not collect substances in the part that can be moved mechanically, for example a water jet pump, like the air pump. The air pump 11 is located in the lower region of the fixed bed reactor 8 and pumps up the fixed bed carrier material with thick biomass, while present in the upper region of the reactor housing, and Carrier materials with very little biomass slide upward. This circulation will be described in detail below with reference to FIG.

According to the embodiment according to FIGS. 1 and 2, a large number, here a total of four, of the air pumps 11 are located on the bottom surface of the floor 4, ie for the cross section of the housing 1, It has been shown that it is advantageous to be provided evenly distributed over the base surface and the cross section. Each air pump has a certain geometrical working area around its lower end 12, which sucks in the carrier material, in which the carrier material is also sucked. The arrangement of the air-lift pump is such that the air-lift pump acts on all areas of the base surface of the floor 4, i.e., the carrier material present there is sucked.

The fixed-bed reactor according to the invention operates on the co-current principle described in particular. That is, the water and air to be purified flow from the bottom to the top in the same direction. In some cases, it is possible to guide the water to be purified from above to below (countercurrent principle). Continuous operation is advantageous.
Discontinuous operations in which wastewater from a reservoir is treated in a batch mode are also within the scope of the present invention.

The biological wastewater treatment according to the present invention is performed under aerobic (carbon decomposition, nitrogen oxidation) conditions, anaerobic (carbon decomposition where methane is recovered) or oxidizing (denitrification) conditions. It is. For this purpose, known denitrification and nitriding steps are performed. No superstoichiometric dosing of the carbon source is required. The above-described method and the device therefor are known in the prior art and will not be described in detail here.

FIG. 3 shows an air lift pump 11 having a lower end 12 into which a mixture of contaminated wastewater and fixed bed material is drawn in the direction of arrow 15. Most of the contaminated wastewater flows upwards through the fixed bed reactor 8 in the direction of arrow 7. The contaminated water flows out through outlet 16 together with the incoming fixed bed. The fixed bed material is fed back in the direction of arrow 17 through a funnel-shaped cavity 20 to the surface of the fixed bed present in the reactor. This funnel-shaped hollow space or gap 20 is provided on the outside with a hopper 23
Accordingly, the inside is partitioned by another hopper 24. Countercurrent to the flow direction of the fixed bed material in the direction of arrow 17, a small flow of biologically purified wash water flows into the hollow chamber or hopper slit 20 in the direction of arrow 19, At that time, the purification of the fixed bed material is completed. The above stream of biologically purified wash water comes from the upflow of the fixed bed. The power that enables this water supply 19 is obtained by the fact that the level 21 in the cleaning device 13 is below the level of the upflow of the reactor, ie in the outlet 10. The amount of water sent according to arrow 19 and the amount of water sent by air pump 11 are small compared to the amount of water flowing through fixed bed reactor 8 in the direction of arrow 7. This circulates through the fixed bed reactor, i.e., feeds the fixed bed material from the region below the reactor housing into the region above it, as well as the carrier material previously present in the region above the reactor housing. A corresponding sliding down and thus the desired uniform distribution of the active biomass throughout the reactor vessel and thus over the entire height of the reactor interior is achieved. The water sent according to arrow 19 and the water sent by air pump 11 both flow out of the muddy water outlet in the direction of arrow 18 for sludge treatment. The clarified mud is sent back from there and supplied to the reactor. At that time, the wastewater sent through the air pump is not biologically purified. The clean water purified by the fixed bed flows to an outlet 10 not shown in FIG.

By the above-described method, the particulate fixed-bed material is released from the loose biomass, particularly in the washing device 13. This biomass is formed in particular in the region below the reactor. This is because the "nutrition" supplied by the water purified therein is particularly rich in biomass, and the biofilm is correspondingly significantly enriched into biomass there. For this purpose, a small fraction of purified wastewater flowing in the area above the reactor (see also above) is guided in countercurrent countercurrent to the purified fixed bed material. It is sucked as mud with waste water sent by an air pump. The fixed bed material leaves the air lift pump via the fixed bed exit according to arrow 17 and rests on the fixed bed present in the reactor as described above. The mud is stripped of its solid contents outside and sent back to the reactor.

With one of the methods according to the invention, the speed of movement of the fixed bed in the reactor can be changed. In addition, the circulation of the fixed bed can be performed intermittently with a middle break during the period. This is achieved by appropriate modification and control of the conveying air in this embodiment of the air pump or by appropriate modification and control of the transfer means provided in place of this air pump for the carrier material forming the fixed bed. It is.

[0022]

Overall, it is an advantage of the present invention that such fixed bed circulation is achieved with a reduced and simplified number of structural measures to be provided. In particular, large units such as wash pumps and wash vents provided in other devices for biological purification need not be provided. In particular, fixed-bed reactors provided for the purification of biological wastewater, regardless of the rewashing or recirculation system, are only sized to meet the requirements of biological wastewater purification. The advantage of only having to do it,
And furthermore, the device according to the invention has the advantage that it can be retrofitted to existing fixed-bed reactors.
The best use of the place is achieved. A satisfactory and even distribution of the biomass in the fixed bed is achieved, which makes it possible to better identify the load peaks in the mud to be treated.

All features shown and described in the figures and combinations of these features are important to the present invention, unless explicitly stated as explicitly known.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a fixed-bed reactor according to the present invention.

FIG. 2 is a sectional view taken along section line II-II in FIG.

FIG. 3 is an enlarged view of detail III in FIG. 1 with the reactor housing and cover omitted, including the air pump.

DESCRIPTION OF SYMBOLS 1 Housing 2 Cover 3 Closed part 4 Floor 5 Supply part 6 Nozzle 7 Arrow 8 Fixed floor reactor 9 Support layer 10 Outlet 11 Air pump 12 Lower end 13 Cleaning device 16 Outlet 17 Arrow 18 Arrow 19 Arrow 20 Hopper slit 23 Hopper 24 Hopper

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Günther Roman, 92224 Amberg, Gümberstrasse, Germany, 4 (72) Inventor Hilmar Teifel, Germany, 92265 Edelsuf Elt, Lower Nielnund Nummer 6

Claims (12)

[Claims] Claims: 1. A reactor housing is provided, in which a fixed bed of carrier particles coated with biofilm is present, in which supply and discharge of purified water flowing through the fixed bed is provided. A fixed-bed reactor for purifying wastewater, which is provided with means for circulating the fixed bed and feed means for circulating the carrier particles in the fixed bed in a region below the reactor housing (1). A substantially flat and horizontally oriented floor (4) for introducing purified water into the reactor housing;
A fixed floor (8) is placed on the floor, the wall of the reactor housing is vertically oriented upward from the floor, and is present below the feeding means (11). Fixed floor reactor characterized in that the end (12) lies directly above the floor 02. The fixed-bed reactor according to claim 1, wherein a water / solid matter pump based on the principle of suction by air, such as an air lift pump or a water jet pump, is provided as the feeding means. 03: adapted to the size of the surface of the floor (4), ie to the size of the horizontal cross section of the reactor housing (1),
A suitable number of pump means (11) are provided uniformly distributed throughout the horizontal cross section of the reactor housing, the working zones of the individual pump means being arranged at least over the entire area of this cross section. 3. The fixed-bed reactor according to claim 1, wherein a remarkable area on the entire surface of the cross section is provided so as to be overlapped so as to receive the action of the pump means. 4. The fixed-bed reactor according to claim 1, wherein the means for supplying air is present in the floor (4). 05. The device as claimed in claim 1, wherein the means for supplying air is provided at a distance from the floor and below the fixed floor. Fixed floor reactor. 06. A support layer (9), especially of coarse-grained material, for the fixed bed (8) is provided above the floor (4) and rests on it. 6. The fixed-bed reactor according to claim 1, wherein the lower end of the one or more pump means terminates directly above the support layer. 07. A washing device (1) for separating loose biomass from granular carrier material in a fixed bed (8).
7. The fixed-bed reactor according to claim 1, wherein 3) is provided in a region above the reactor housing (1). 08. A method for operating a fixed-bed reactor, characterized in that the water to be purified flows from below to above the reactor housing in a co-current principle. 09. A method for operating a fixed-bed reactor, characterized by applying the countercurrent principle of flowing the water to be purified from below to above the fixed bed (8). 10. The method according to claim 8, wherein the operation is carried out continuously or discontinuously under feeding. 11. The circulation rate of the carrier material in the fixed bed is changed by appropriately adjusting the feeding means, for example, when using an air pump, by adjusting the amount of air fed. The method according to any one of 8 to 10. 12. The biological wastewater treatment is performed under aerobic (carbon decomposition, nitrogen oxidation) conditions, anaerobic (carbon decomposition in which methane is recovered) or oxidizing (denitrification) conditions. The method according to any one of claims 8 to 11, characterized in that: