DE3208977C2 - Method and device for the microbial degradation of organically contaminated substrates - Google Patents

Abstract

In a process for the microbial degradation of organically polluted substrates, the degradation is carried out in two or more stages and takes place in separate containers, in such a way that the pressure, temperature, pH and / or the chemical and / or microbial composition of the individual stages can be set and in each stage the substrate and the microbes growing in it are exposed to a defined shear or mixture. In this way, it is possible to change all process parameters independently of one another in each stage, to expose the substrate and the microbes formed therein to a defined shear or mixture, and to discharge the gas formed in the substrate by means of a negative pressure generated at certain time intervals. The dwell times can thus be reduced considerably.

Description

ä) for shearing the substrates in the containers (11, 21) one or more VVendel stirrers (41) are provided, with de. or the spiral agitator (41) has a spiral agitator blade (43) have, which is attached to a rotatable axis (42) and with a plurality of Recesses in the form of holes (44) is provided, or

b) the containers (11, 21) are provided with internals (54, 64, 64 ', 64 ") for shearing the substrates, the perforated plates (55) arranged as axially perpendicular to the flow direction of the substrates Smooth or uneven perforation (56) or designed as a nozzle plate (66), or

c) for shearing the substrates, the internals according to b) are designed as filler bodies (57).

5. Device according spoke 4, characterized in that the nozzle plates (66) with in series and / or recesses (67) or punchings arranged offset from one another which each have an inward or outward mauve (S3 / am) formed by a bend (68).

6. Apparatus according to claim 4, characterized in that that the filling bodies (57) are arranged side by side on circular rings (58) with a lateral spacing Stegs (59) exist.

7. The device according to claim 4, characterized in that for the outflow of the container internals (54; 64, 64 ', 64 ") and / or for transferring the substrate from one container (ti) to another container (2t) in each of these by pressure medium movable membrane (51; 61) is used.

1st fermentative step - here the organic components are broken down into organic acids, among other things, whereby hydrogen (II ₂ ) and carbonic acid (CO ₂ ) are formed,
2nd methanogenic step - here methane (CH ₄ ) is formed mainly from acetic acid or hydrogen (H ₂ ) and carbonic acid (CO _{2) by various methane bacteria.}

The fermentative scuritt shows the following characteristics: The acetic acid concentration or the hydrogen concentration controls the metabolic pathways and the activity of the fermentative biocenosis, i. This means that when acetic acid (H ⁺ ) has reached a certain concentration, other fatty acids are formed. Under

Under certain circumstances, butanol or ethynol is even produced. Butyric acid, for example, cannot be used by the previously known methane bacteria. Ez is therefore another group of bacteria necessary to these "non mehtanogenen" substances usable to directly convert as acetic acid. These reactions are often thermodynamically only possible if they are drawn through exergonic reactions, such as the methane formation reaction from acetic acid (bio-energetic symbioses).

A single-stage process (Lit I) is known for aerobic diproportionation processes, but it is susceptible to substrate impacts (acidification, etc.). To increase the process stability, a two-stage process management has therefore already been discussed (lit. 2). For example, the Rcsktcrrsu ™ se unicrtsüt, DSSS azs according to another procedure, "Lit 3 ^Y. Substrate first flows through the first space and fatty acids are formed in the process, and then subsequently flows into the second part of the container, in which the fatty acids are converted into methane.

With this two-step process, however, the disadvantage remains that one change: the parameter in the first stage, such as B. pH value change, pressure change, temperature change etc. inevitably in the second stage continues.

The invention is therefore based on the object of providing a method and a device for microbeing To break down organically polluted substrates,

these disadvantages should be avoided. It should rather, what is achieved is that all process parameters can be changed independently of one another in each stage are, so that the degradation in the individual stages under optimal conditions and in a considerable> shorter time than before.

The inventive method by means of which this to is to accomplish, is specified in claim 1.

It is useful here, by generating a preferably discontinuous and / or pcriodi- n> see negative pressure in the individual containers to discharge the gas produced in the substrate, and that from Gas discharged from one container can be entered into another container.

It is also advantageous to interrupt the d 's K'i. Nung at π certain time intervals so that sedimentation can occur.

The apparatus for Anwendi _"3 of this procedure genpviL ⁷ ^ iS in claim 4

The containers can hereby rid '- jnzentrisch be interconverted dnet ^eor 3ng ^7, wherein the tank should be installed with the respective Tihöheren operating temperature in the tank with the next lower operating temperature.

One or more helical stirrers can be provided to shear the substrates in the containers each have a coiled stirrer blade attached to a finer rotatable axis and with a ^ Multitude of recesses in the form of holes ^ is provided jo

To shear the substrate, however, can also be used in the

Built-in containers, which are designed as a

: arranged right to the direction of the substrate Perforated plates with uniform or uneven

- Holes or nozzles are formed. J>

The nozzle plates can here with in series

Tind / or recesses arranged offset from one another or punchings, o <e in each case an indentation formed by a bend

or AuslabKanal have. ■ * < >

The built-in containers can also be used as fillers be trained. wood these from bars arranged side by side on circular rings with lateral spacing can exist

For flow to the tank installations and / or to> · 4 $ Transferring the substrate from one container to another, it is also expedient to insert a membrane movable by pressure medium into each of these.

Furthermore, between each zwsii with each other connected containers in their connection-oriented a piston or diaphragm pump can be used, by means of which the diaphragm built into the container are alternately acted upon.

By means of the method according to the invention or the device for applying this method, it is possible to change all the method parameters such as pressure, pH, chemical composition or microbial composition in each strain independently of one another, the substrate and the then w>., emerging; Exposing microbes to a defined shear and removing the gas produced in the substrate by means of a negative pressure generated in certain time intervals. Defined shear should be understood to mean that a certain group of *> 5 microorganisms is exposed to a shear stress that is so optimal for them that the bioenergetic symbioses take place with the highest degree of efficiency.

In the drawing are some exemplary embodiments of the device designed according to the invention on the microbial degradation of organically contaminated substrates and explained in detail below. Here shows, each in a schematic representation

F i g. 1 the device consisting of two separate containers.

F i g. 2 the device according to FIG. 1 with containers arranged one inside the other,

F i g. 3 a spiral stirrer intended for mixing,

4 shows an inflatable membrane with an inflatable membrane and Built-in container,

F i g. 5 is a plan view of one of the container internals of the container according to FIG. 4,

6, 7 and 8 each one with a membrane as Pulse generator and differently designed container structures provided with containers,

F i g. 9 shows a section of the internals of the container according to FIGS. 6 to 8,

Fig. 10 two puttied with membranes and over a piston pump interconnected containers and

F i g. Π a built-in container designed as a filler body.

The in F i g. 1 shown and denoted by 1 device for the microbial degradation of organically contaminated Substrate consists of two separate but interconnected containers 11 and 21, the container 11 having a substrate entry 12 and the container 21 is provided with a substrate discharge 23. Via lines 13 and 2Z, via a pump 20 are connected to each other, the two containers are 1 ί and 21 connected to each other, each of the containers 11 and 21 is equipped with a return line 14 or 24 and a sediment discharge 15 or 25. In the Return lines 14 and 24 connected to the respective Line 13 (discharge) or Substrataust.ag 23 are connected, here are also pumps 19 and 29 used.

Furthermore, the containers 11 and 21 each have a gas outlet 16 and 26, which is provided with a shut-off valve 17 and 27, respectively. When the shut-off valves 17 and 27 are open, the gas generated in the container U or A can flow out via overpressure valves IS and 28, respectively

That in the container il in which the step! The microwave breakdown of organically contaminated substrates is carried out, for example, at temperatures of 32-38 C, but the gas generated can only be used in the container 2i. for stage II, the z. B. at temperatures of 50-60C. are fed. For this purpose, the gas discharge 16 is connected to the container 21 via a line 30. A pump 3 * is inserted into the line 30 so that the gas is pumped out of the container II and a negative pressure can thus be generated. In this way, the gas volume is increased. The gas accumulating under pressure in the container 21 can be sucked off and consumed with the aid of a pump 33 inserted in a line 32. Heating the container IJ and / or 21 can be done in a conventional manner .;

The device Γ according to Fig.2 corresponds in all Details of the device 1 according to FIG. 1, but are in this embodiment the containers 11 'and 21' arranged one inside the other The individual parts of the device 1 'are therefore given the same reference numerals provided, but to distinguish them each would be marked with a (').

The substrate introduced into the containers 11 or 11 'is degraded in this in a stage 1, the individual process parameters being influenced independently of the process parameters of stage II, which subsequently takes place in the containers 21 or 2Γ.

The spiral stirrer 41 shown in Figure 3 consists from a wired pipe tt 43, which is attached to an axis 42 is attached and has holes 44 The number and The size of the holes 44 and the pitch of the turn can be depending on the intended use; can be selected. Will If a container diameter of 20 cm is chosen, the The stirrer diameter can be 19 cm, for example. At a The stirrer has an axis length of approx. 1 m from IO full helices. The hole diameters vary between approx. 05 and 2 cm. The number of holes per full helix results from the total hole area per single helix. It can vary from type of microbe to microbe type Also prove to be convenient, the hole size from below to vary upwards.

Wrong, case of the concentric arrangement of the containers 11 'and 21' according to FIG. 2, the helical stirrer 41 in Outer container be designed as a helix. The drives of the stirrers can, if necessary, be independent be from each other. The flat shearing device (spiral stirrer) supports the removal the gases from the liquid phase.

In the configurations according to FIGS. 4. 6. 7 and 8 is a membrane 51 or 61 in each case in the container 11 used to keep the substrate moving. In addition, there are permanent fixtures 54 and 64, respectively provided, which in the execution according to the F i g. 4 and 5 consist of perforated plates 55 provided with perforations 56. The internals 64 can also be used as Nozzle plates 66 are formed in which according to F t g. 9 in this slot-like recess 67 and on these subsequent bends 68 are incorporated so that inlet or outlet channels 69 arise. That The substrate is thus forced to flow through these channels. That way, a good one is made Mixing.

Since the container internals 64 'and 64 "in the Embodiments according to FIGS. 7 and 8 different Have directed flow channels are by means of the membrane 61 also generates different substrate currents. This is indicated by the arrows drawn in marked A, in this way the Mixing of the substrate supported

In the exemplary embodiment according to Figure 4 is the Membrane 51 is designed as a bladder, into the pressure chamber 52 of which pressure medium can be introduced via a line 53 According to FIGS. 6 öis 8 can the membrane 61 with her Edge area but also firmly clamped as a partition wall in the container 11, so that at a Pressure medium supply via the line 63 into the pressure chamber 62 thus formed is pulsating Movement that is transmitted to the substrate is caused. And by the flow of the Internals 54 and 64, this is subjected to a defined shear.

According to FIG. 10, the pressure spaces in the Container 11 and 21 built-in membrane 61 also through a line 71 may be connected to one another, into which a piston pump 72 is inserted. The membranes 61 and 6Γ, by means of which the entry, the carryover and the Discharge of substrate can be made, are thus acted upon alternately.

A filling body 57 can also be used as a container installation can be used, as shown, for example, in FIG. 11th is shown on circular rings 58 are here at a distance from one another webs 59 so that a large surface is created on which microbes can settle.

ίο; The internals 54; 64 and the packing 57, which are used for Shearing the substrate can be used to assist the elimination of gases from the liquid phase.

The hydrogen produced in the fermentative step has an inhibitor development with increasing concentration. This effect is reinforced by Solid (sludge particles or lignin structures). on which local nests of hydrogen form. Of the The advantage of this invention is therefore that the substrate is sheared in the openings of the built-in containers.

that such nests are destroyed, but without doing so To achieve shear forces that the microorganisms in affect their pr <^ _ ίοπ negatively. Through suitable Formation of the spiral stirrer (turning angle / perforated surface) or the container built-in o (number. arrangement.

Hole shape, surface) it is also possible. Segregation effects on the surface of the substrate column or to avoid or promote on the ground.

The Au ^<: 'ducation the tank installations creates a very large surface area on which the microbes settle in the form of a lawn. This increases the microbe concentration in the containers because fewer microbes are carried away with the substrate. However, there is a direct correlation between the microbe concentration and the dwell time of the substrate in a container in such a way that the dwell time decreases with increasing microbe concentration to further support the degassing of the substrate in the respective stage by generating a negative pressure and to remove these gases from the individual container. The gas flow from the individual containers can be separated into other containers for further microwave processing. In addition, the optimal process parameters, such as pressure and temperature, found for the respective substrate in the laboratory test can be used in each stage. pH chemical and microbial composition can be adjusted and regulated. In this way it is possible to reduce to a fraction the residence times in such anaerobic processes, which were still very lazy up to now.

Litl: D E-AS 27 28 585
LiL 2: Lettinga et al

Biotechnology and Bioengeneering 22, 1980, Pp. 699-734

Lit 3: "Biogas plant" publication from the MBB company ^ Space travel, Munich and planning office and

agricultural plant construction Schraufstetter, Ismaning.

In addition 6 blue drawings

Claims (4)

Patent claims: 1. Process for the microbial degradation of organically polluted substrates, the degradation in two or is carried out in several stages and takes place in separate containers, in such a way that that the pressure, the temperature, the pH and / or the chemical and / or microbial properties The composition of the individual levels can be set individually by the remaining levels, characterized in that the substrate is subjected to such shear at each stage that the bioenergetic symbioses run with the highest efficiency. 2. The method according to claim 1, characterized in that by generating a preferably discontinuous and / or periodic negative pressure in the individual containers (II, 21; 11 ', 21') r the gas generated in the substrate is discharged l ~ 3. The method of claim \ gekenfiilzeichnet characterized in that the from a container (11; 11 ') discharged gas ^ into another container (21; 2V) - ^ is entered. 4. Device for carrying out the method: make one of claims 1 to 3, wherein each stage ^{: r is assigned} a separate container, the spatially separated containers are connected to one another via lines provided with pumps and / or valves, or the Containers! Are arranged concentrically one inside the other, characterized in that The invention relates to a method and a device for the microbial degradation of organically polluted animals Substrates according to claims 1 and 4. Claims 2, 3 and 5 to 7 name embodiments of the Invention. Organic as well as inorganic waste compounds can be broken down by microorganisms both aerobically and anaerobically.
It is known that the aerobic treatment ic waste materials under constant oxygen supply in aeration basins disproportionate to carbon dioxide and biomass by bacteria. The here free The energy that is generated is given off to the environment in the form of heat. The biomass (secondary sludge), which inevitably arises in aerobic wastewater treatment, is often used in a second Treatment stage (digestion tower) stabilized. This creates Methane and carbonic acid. Aerobic and anaerobic treatments of organic waste materials can stand on their own as disproportionation processes in their own right operate. The anaerobic degradation of organic substances takes place e.g. in several steps, namely