JPS5941800B2 - Method and apparatus for treating anaerobically digested sewage sludge - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for treating sludge produced as a by-product of public sewage purification.

Furthermore, the present invention relates to a process for producing a supernatant liquid which is separated during the process and is suitable for the growth of microorganisms, and to a process for producing products containing bacterial proteins and vitamins obtained using this supernatant liquid.

For solutions to public sewage purification, it has long been a goal to eliminate or utilize in a certain way by-products that seriously pollute the environment.

In the Sewage Purification Act, it is now absolutely necessary to place first priority on the requirements of environmental protection and to reduce the cost of sewage purification.

To stabilize putrefying by-products produced during the purification of public sewage, e.g. "primary sludge" obtained from primary settling tanks, secondary sludge obtained after biological treatment, or mixtures thereof. , the most commonly used method for stabilizing crude sludge is anaerobic fermentation.

The fermentation process is often connected to a secondary fermentation tank, primarily for dewatering purposes, and the anaerobically digested, already stable sewage sludge is removed from the digestion tank.

Several methods are known for disposing or utilizing digested sewage sludge.

The first treatment step concerns the concentration of the sludge, the most advanced of which involves placing the sludge on a drying bed, which is a highly uneconomical process that requires a large area and has low productivity.

Another method is mechanical dehydration followed by incineration.

Incineration is an energy-intensive method and the useful substances of sewage sludge cannot be utilized in this method.

Modern methods offset the diseconomies of sewage sludge disposal by utilizing the useful components present in the sludge.

Examples include the use of ash produced by combustion, methods of drying dehydrated sludge rather than combustion, methods of spreading dried sludge on cultivated land either as it is or by mixing it with other substances, and methods of producing compost. be.

The use of sludge to amend soil is not practiced because its value is not commensurate with the labor-intensive transportation and transportation required.

Furthermore, this method has the disadvantage that the biologically available substances of the sewage sludge are only indirectly of low efficiency and little use for animal husbandry.

In a separate processing step, one of the sludge components is recovered.

One example is the recovery of the highly useful vitamin B1□.

With this method, disposal of the remaining material remains a difficult problem.

In the method according to German Patent Application No. 2504412, activated sludge is stabilized by partially anaerobic and then aerobic decomposition.

Digested sewage sludge is used for fertilization as a final product after drying.

The advantage of partial anaerobic digestion is that the residence time in the fermenter is short due to the high solubility and, moreover, most of the combustible gases produced under the conditions of anaerobic fermentation are released during this period and are rapidly decomposed. A further aerobic decomposition step (previously partially dehydrated) may result in a more applicable product.

However, even this method only yields soil conditioners.

According to the method described in Hungarian patent no. Paddy sludge is fermented semi-continuously using nutrients (medium).

In this way, vitamin B1□ is also produced in the fermenter, and at the same time the amount of biomass is increased.

The surplus biological material produces a large amount of fermentation sludge, which contains vitamins and is therefore suitable as a feed additive, but the protein content is not higher than that of fermentation sludge obtained from conventional use.

From the natural bacterial population of the anaerobic digestion of sewage sludge originating from sewage purification, species suitable for the production of vitamin B1□ and proteins can be enriched, for example according to Hungarian Patent No. 153,740.

According to this method, a group of bacteria further cultured from the digested sewage sludge in an appropriately selected medium is used for the production of vitamins and proteins, but it is not necessary to use the sewage sludge itself for culturing the bacteria.

Therefore, the invention does not solve the problem of sludge cleaning by-products explained at the beginning.

The method described in Sueten Patent No. 471,540 is aimed at using sewage sludge for breeding.

According to this method, activated sludge, alone or mixed with additives, is fed into a continuously operated extruder, briefly heated to 105-160°C, followed by rapid expansion. , and finally air dry the product.

Expansion produces a product suitable for direct feeding from the sludge material.

Because the sludge itself contains large amounts of ballast material and other materials, its use by higher animals is uneconomical due to its low protein content, and this method therefore does not fully utilize the rearing potential inherent in the sludge.

The purpose of the present invention is to treat sludge primarily arising from public sewage purification processes, so that the sewage sludge is treated in its entirety, so that no deposition, for example, in a drying bed is necessary, and at the same time, as a result of the treatment, the useful The object of the present invention is to provide a solution in which organic and inorganic substances, mainly proteins, vitamins and metals, are utilized in the form of end products in a manner that fully corresponds to the health and hygiene requirements and is suitable for direct animal husbandry.

The present invention shows that when appropriately heat-treated anaerobically digested sewage sludge is separated into a concentrate and a supernatant, the supernatant unexpectedly grows microorganisms, including selective growth of methanol-utilizing bacterial groups. and thus, for example, for the production of protein-rich biological products.

Heat treatment destroys pathogenic bacteria and thus actually sterilizes the sewage sludge, while at the same time the polymeric components of the heat-treated supernatant become more suitable for enzymatic degradation and the composition of the final product becomes more stable in case of protein fermentation. This makes it more suitable for breeding, and at the same time the separation of the sludge phase into supernatant and concentrate is carried out more favorably.

Methanol added to the heat-treated supernatant to make the culture medium acts as a ``selective sterilization'' agent insofar as it prevents the growth of pathogenic bacteria.

Finally, drying the biological material actually stabilizes it, in other words, prevents its deterioration.

The deterioration will occur in a very short time unless it is dried.

Furthermore, according to the invention, the equipment necessary for the removal and utilization of sewage sludge can consist of appropriately selected items for this purpose, such as tanks, pumps, appliances, equipment, etc., which are known per se. , these are used separately in the fields of sewage purification and fermentation, but they are connected in a special way and used together, resulting in the complex function of processing sludge into sterile nutrients into one rationally engineered device. It is based on the recognition that the entire device can be constructed at the site of sewage sludge production, for example at or in the vicinity of the sewage plant.

Based on these realizations, the object of the present invention was solved by a method and a device useful for the utilization of anaerobically digested sewage sludge.

Carry out the following sequence of operations: a) Heat the anaerobically digested sewage sludge to at least 80°C.
b) heating the heat-treated anaerobically digested sewage sludge to a sludge concentrate and supernatant, optionally in the presence of a coagulant; C) adding an alcohol having 1 to 3 carbon atoms, preferably methanol, at least one nitrogen-containing inorganic salt, optionally a water-soluble vitamin precursor and growth factors to form a medium; d) inoculating the medium with anaerobically digested sewage sludge in an anaerobic manner; e) fermenting the inoculated medium in an anaerobic manner at a temperature of 26-38°C; and f) fermentation liquid produced during the fermentation. Separate biological material from

According to another feature of the invention, it is advantageous to dry the biological material by spray drying.

The main features of the equipment are: a heat exchanger suitable for heating and cooling sewage sludge, a device for separating heat-treated sewage sludge into supernatant liquid and sludge concentrate, and a device for producing culture medium using supernatant liquid. It is to have a tank, a fermenter suitable for the fermentation of the medium, as well as a separator suitable for the selection of the biological material formed from the fermentation liquor in the fermenter.

The present invention further relates to the following;
■ Supernatant liquid (medium) suitable for the growth of microorganisms obtained by heat treatment and separation of sewage sludge, characterized in that: 2) a) crude protein content is greater than 50% by weight; b) Rich in nutrients suitable for breeding, obtained by anaerobic fermentation of a medium (supernatant) obtained by heat treatment and separation of sewage sludge, characterized by a total water-soluble vitamin content of more than 1000 γ / g , a protein and vitamin rich product.

The advantageous effects achieved by the invention are as follows: Sewage sludge is used according to the invention to process into highly useful products suitable for animal husbandry, with a high protein and vitamin content or metal content. However, its storage and removal have been the most serious difficulties and unresolved problems in sewage purification.

The elimination of this important hygiene-environmental protection problem not only makes it possible to produce sterile products from hitherto unutilized sources of excretory proteins and vitamins that are eminently suitable for animal husbandry, thereby reducing sewage purification costs. , succeeded by creating significant new value.

The equipment investment and operating costs are relatively low compared to the results.

After treatment of the sludge, no additional harmful by-products remain.

Another advantage is the high energy content of biogas (bioga
s) The production is also increased by fermentation of the supernatant.

The composition of the main product produced by the method of the invention, suitable for breeding (see Examples 1, 5, 6 and 7 below), is compared with the composition of digested sewage sludge removed by conventional sewage purification methods. It is shown in Table 1.

These data clearly demonstrate the significance of the results achieved by the present invention.

Next, the present invention will be explained in detail based on the drawings.

The drawings include a system diagram showing the equipment and material flow for carrying out the method of the invention.

In the drawings, FIG. 1 is a system diagram of one embodiment of the apparatus, and FIG. 2 is a system diagram showing the flow of materials belonging to a specific example of the method of the present invention.

FIG. 1 also shows pipes indicating the equipment units and arrows indicating the flow of material at the inlets and outlets, so that the technological steps can be easily followed.

The digester 1 is part of a complete sewage treatment plant, the rest of which is not shown in detail.

A crude sludge inlet 2 and an outlet 3 are connected to the digestion tank 1 .

Outlet 3 conveys the biogas generated during the anaerobic digestion process to a storage tank (not shown).

The digester 1 is connected to a storage tank 7 by a vibro having a centrifugal pump 5 .

The storage tank 7 is connected by pipes 8 to a heat exchanger, indicated in its entirety by the reference numeral 9.

A centrifugal pump 10 is incorporated into the pipe 8.

Heat exchanger 9 has heat exchange units 11 and 12.

The heat exchange unit 12 heats the sewage sludge and the heat exchange unit 11 cools it, so the steam pipe 13 enters the heat exchange unit 12.

The heat exchange units 11 and 12 have pipes 14 and 12, respectively.
15, pipes 16 connect the heat exchange unit 11 with a gravity settling tank 17, into which a mixing vane 17a is inserted.

The settling tank 17 has a pipe 19 with a centrifugal pump 18
It is also connected to the reagent dissolving device 20 via.

The water supply pipe 21 communicates with the pipe 19.

A pipe 22 is provided at the bottom of the settling tank 17 and is connected to a centrifugal pump 23 .

A pipe 24 with several delivery branches connects to the settling tank 17.
It enters the pipe 22 from the top in front of the pump 23.

Feed pipe 24 exits centrifugal pump 23 and enters decanter centrifuge 28 .

Pipe 25 branches off from pipe 24 before centrifuge 28 .

The pipe 25 enters a tank 26 that collects the supernatant liquid (lower left in Figure 1).

Pipes 27 and 28a exit from decanter centrifuge 28.

Pipe 27 enters pipe 25 and pipe 28a connects the centrifuge with concentrate storage tank 29.

The concentrate storage tank is provided with a mixing vane 29a.

The concentrate storage tank 29 is connected to a rotary dryer 32 by a pipe 31 with a centrifugal pump 30.

A homogenizer 33 is provided below the outlet of the dryer 32, and a bagging scale 34 is provided further below.

The tank 26 for collecting the supernatant and producing the culture medium is also connected via a bump 37 with a centrifugal pump 36 to a fermenter 35 installed in a recess.

Steam pipe 38 and water pipeline 39 enter tank 35.

The tank 26 is connected via a pipe 42 to a storage tank 40 containing methanol necessary for producing the culture medium.

The pipe 42 is connected to the automatic starting pump 41 (for example, “5IH
It has a type I automatic start methanol pump).

Tank 26 has a mixing vane 26a or similar device.

The tank 26 is connected via a pipe 44 with a centrifugal pump 43 to a fermenter 45, which is supplied with a pipe 45a for feeding digested material, in particular anaerobically digested sewage sludge.
is open.

A discharge pipe 46 is for removing the biogas, and a pipe 48 containing a centrifugal pump 47 feeds the fermentation liquid into a storage tank 49 with mixing vanes 49a or similar elements.

A pipe 52 containing a centrifugal pump 51 supplies the fermentation liquor from the tank 49 to the separator 50 .

The product is conducted from the separator 50 via a pipe 54 into a storage tank 53, and a pipe 55 is used to circulate the supernatant liquid separated in the separator to the sewage purification system.

Starting from the tank 53, a pipe 57 with a centrifugal pump 56 enters the upper part of the grinding dryer.

The homogenizer 59 is located below the crushing dryer and has a bagging scale 60 below it.

Gate valves or similar devices known per se may be provided in the device where and in the necessary quantities, but have been omitted for the sake of greater clarity.

However, their location and purpose will be clear to those skilled in the art.

The anaerobically digested sewage sludge is treated using the apparatus according to FIG. is supplied to a storage tank 7 by a centrifugal pump 10, and from there to a heat exchanger 9 by a centrifugal pump 10.

The capacity of the digester tank 1 is approximately 10 times the capacity of the crude wastewater that is fed during sewage purification.

Before being fed into the coarse sludge from the digester 1, an amount of sewage sludge is always removed that is equal to the amount of feed coarse sludge.

These functions may equally be performed intermittently, semi-continuously or continuously.

Semi-continuous operation means that the removal and supply functions are once a day or 8 to 1
Conducted every 2 hours.

If necessary, the temperature in the digester 1 is maintained in the temperature range of 30-35°C by cooling or heating.

Advantageous pH values for anaerobic digestion are 7-8, which in the acidic case can be adjusted by adding a base, especially milk of lime.

The sewage sludge is passed through the units 11 and 12 of the heat exchanger 9, the sludge being first heated to 80°C, preferably 100°C.
It is heated to a temperature of ~150°C, then cooled to a temperature of about 40-80°C and conveyed into a settling tank 17.

The microbial population of the sewage sludge, including pathogenic bacteria, is destroyed by this heat treatment, in other words the sludge is sterilized.

Moreover, as a result of the heat treatment, the sludge becomes more manageable with respect to temperature, while the supernatant liquid is in a more favorable condition for further processing.

In the heating range, when the temperature is low, a long heating time is required, and when the humidity is high, a short heating time is required.

During the heat treatment process in the settling tank 17, the recooled sludge containing partially solidified suspended solid particles is treated with some coagulant, while vigorously stirring the contents of the tank, to facilitate separation of these particles. for example inorganic or organic electrolytes such as aluminum sulfate, iron sulfate or polyacrylates,
Polyacrylamide can be added.

Amphoteric colloids (e.g. natural gut) or organic non-electrolytes (
For example, starch) can also be used as a coagulant (Flockungsmittel in Wass).
erAufbereitungstechnik, Ch.
em.

Rdsch, /5olothurn/20,673-6
77/1967).

In selecting the coagulant, the fundamental thing is that the coagulant does not interfere with the use of the final product as a feed additive.

Therefore, easily degradable 1, C, C1 earflock AN
IO (a product of Industrial Chemicals and Equipment Company) is preferred as coagulant.

The coagulant is added to the sewage sludge as an aqueous liquid and subsequently allowed to settle, preferably for 2 to 6 hours.

It is also advantageous to use aluminum sulfate solution as coagulant.

In some cases, the addition of a coagulant can be omitted, since settling in the tank 17 can also occur without a coagulant.

The settled sludge from the lower part of the tank 17 and the supernatant liquid from the upper part of the tank are taken out equally by means of a centrifugal pump 23, which of course requires a gate valve installed in the pipeline system (
(not shown) must be activated as required.

The decanted supernatant liquid is fed into a storage tank 26 via a pipe 25, and the sludge is transferred to a decanter centrifuge 28.
It is carried inside from the pipe 24.

By the decant operation, about 30 to 50
% by volume of concentrate and 50-70% by volume of supernatant.
Obtained with a concentration efficiency of 90 to 0.95.

The dry matter content of the concentrate is approximately 12-18% and that of the supernatant is 0.5-1.0%.

In the centrifuge 28 the concentrate is further hydrated, in this step a 30-50% by volume concentrate and also a supernatant are obtained.

The dry matter content of this concentrate is 30-40%.

This concentrate, which has a high dry matter content, is fed by pipe 28 into a concentrate storage tank 29 and from there sent by centrifugal pump 30 to a rotary dryer where it is dried and/or heated until it is free of organic matter. be done.

Drying is carried out at a maximum humidity of 150°C.

This is because at higher temperatures useful proteins are destroyed.

This dry material is designated as by-product I, and the heated material is designated as by-product ■.

This by-product is useful; the former has a significant protein content, the latter a high metal content.

They can therefore be used alone or in admixture with each other and/or with other substances, such as the main product obtained by the process according to the invention, for animal husbandry.

The mixing and supplying operation is carried out by a homogenizer 33 and a bagging scale 34.
Accurately implemented.

The supernatant liquid obtained as a result of decanting in the centrifuge 28 is conveyed by a pipe 27 into the same pipe 25 that conveys the supernatant liquid obtained in the settling tank to the storage tank 26 .

With the supernatant obtained from the two locations, a medium suitable for fermentation is prepared in tank 25, a fertilizer solution is added to the supernatant as a nitrogen source from tank 35, in particular a solution containing mainly inorganic ammonium salts, and tank 40 1 carbon atom as a carbon source from
~ 3 alcohols, in particular methanol, are added via pipe 42 by means of an automatic starting pump 41, and the known growth factors used during fermentation are added from a further booster 37.

As inorganic ammonium, it is possible advantageously to use ammonium hydrogen carbonate, diammonium hydrogen phosphate or ammonium nitrate or mixtures of these salts.

As growth factors it is possible to use, for example, molasses, glycine, yeast, in particular leaven hydrolysates, magnesium chloride and the like.

Known precursors of water-soluble vitamins can also be added if, during the course of the fermentation, not only biological substances with a high protein content but also main products are produced which are rich in water-soluble vitamins and can be used very favorably. .

Precursors of this type may be pimelic acid, nicotinic acid, etc.

Methanol in the medium actually acts as a selective sterilizer against pathogens.

This is because methanol inhibits the growth of pathogenic bacteria as well as the growth of some other bacterial strains.

The culture medium produced in the tank 26 using the mixer 26a is sent via a pipe 44 by a centrifugal pump 43 to a fermenter 45, in which the inoculum, in particular the inoculum taken from the digester 1, is anaerobically digested. Sewage sludge is added through pipe 45a.

The amount of inoculum is approximately 1/10 to 1/20 of the operating volume of enzyme.
It is.

The capacity of the fermenter 45 is the same as the capacity of the digester 1.

Here, the inoculated medium is fermented by a known anaerobic method,
The generated biogas is guided into a gas tank (not shown) through a pipe 46.

During the fermentation process, a temperature of 32° C. is maintained and the contents of the tank are mixed every 8 hours.

As the fermentor 45 is filled, a group of microorganisms necessary for the production of cellular proteins grow.

This is preferably by continuous or semi-continuous fermentation.

In the case of semi-continuous fermentation, at least once a day, about 10% by volume of the fermentation liquid is fed by centrifugal pump 47 to storage tank 49 and at the same time or after some delay an equal amount of medium is sent into fermenter 45.

The fermentation liquor is conveyed from tank 49 to separator 50, where biological substances are separated from the fermentation liquor.

As a result of the separation operation, a supernatant liquid of approximately 80-90% by volume is formed, which is returned to the biological sewage purification system via pipe 55.

The BOI5 value of the cell-depleted fermentation liquid remaining after the separation of biological substances is 1.
20 to 150, the fermentation liquid hardly puts a load on biological sewage treatment equipment.

The B105 value of the supernatant remaining after centrifugal concentration applied in conventional sewage purification processes is so high that it must be taken into account when sizing biological purification systems.

The concentrate (biological material) obtained after separation of the fermentation liquor, which amounts to about 10-20% by volume of the fermentation liquor taken off, is sent to a concentrate tank 53 from where it is pumped using a centrifugal pump 56.
A pipe 57 leads to a spray dryer 58, which is known per se.

The material obtained as a result of the drying operation is the main product according to the invention, containing approximately 70% crude protein and significant amounts of water-soluble vitamins.

The stabilizing effect of drying on biological matter must be emphasized.

Drying prevents the deterioration of biological material that would otherwise deteriorate very quickly; in other words, it actually preserves the biological material and makes it packageable, transportable, storable, and feedable. .

Next, the present invention will be explained in detail based on examples, or
Use the symbols in the diagram.

Example 1 A system diagram for this example is shown in FIG.

Coarse sludge 10Li day 30771'', operating capacity 300
m fermenter 102.

Fermentation is carried out anaerobically at a temperature of 30-35°C and a pH of 7-8.

3077+3 sewage sludge 103 per day according to supply
Take out.

The sewage sludge 103 contains significant amounts of inorganic and organic substances,
Its total dry matter content averages 7% (2.1 t).

30 m'103 of sewage sludge taken out every day is passed through a heat exchanger 104, where it is heat treated by first heating it at 100°C for 15 minutes and then cooling it to 60°C.

transporting the heat-treated sewage sludge into a settling tank 106;
So, AA2 (SO4)3X dissolved in water 3001
Add 18H2060kg105.

The resulting precipitate adheres to the suspended solid particles of the heat treated and fermented sludge.

That is, the particles solidify further.

The treated sewage sludge is allowed to settle for 4 hours, so that 60% of the total volume can be decanted as supernatant liquid 108.

In the decanting process, the supernatant liquid ism"10B containing 0.54% dry matter (dry matter - 0.1 t) and the concentrate containing 16.7% by weight of solid dry matter (dry matter = 2.0 t) were obtained directly. 12m'107 is obtained.

The supernatant liquid is pumped into a 50 m° storage tank 115.

The concentrate is sent to a decant centrifuge 109 where it is further dehydrated.

Thus 6.5S,? supernatant liquid 111 and a concentrate with a solid dry matter content of 35% by weight (dry matter = 1.9 t)5.
4. '110 is obtained from fermented sludge treated with aluminum sulfate.

A rotary dryer 112 that can adjust the temperature of the concentrated sludge 110
Dry at 140°C in water with 10% powder loss 3.33
771"114 and a dry product were obtained, and this was spray-dried 116 to obtain "by-product 119, 1.771" with a water content of 10%.

Powder loss 117 is 5%.

The composition of "by-product I" 119 in terms of its dry matter content is as follows; By-product I, 119 is further heated at 122 to burn off the contained organic matter 123 to produce by-product (1).

Get 124.

The following substance 120 dissolved in 5.4 m of water was added to the supernatant liquid (2
4,6 m") 118 and mixing in the tank: The supernatant liquid 118 and the substance solution are mixed together in a storage tank of 50 771" and thus into an empty tank, fermenter 121, with a working volume of 300 m3. Obtain a pumped fermentable medium.

30 m° of anaerobic digested water sludge freshly removed from a conventional sewage treatment plant is pumped into the fermenter 121.

The temperature of the fermenter is maintained at 32° C. and its contents are mixed every 8 hours.

For one start-up operation of the fermenter 121, supply of supernatant liquid and digested sewage sludge 30 as inoculum with the following substances:
Continue supplying m3 for 5 days.

From the 6th day onwards, the fermenter started as described above should be fed with the following substances: 30 m3 of fermentation liquid was removed before feeding, dissolved in 5.4 m3 of drained water and added to 24.6 m' of supernatant liquid: The fermentation liquor 12 is then operated semi-continuously by
Fermentation is continued semi-continuously for 24 hours by removing 5,30771'' and adding 30 m3 of medium (dilution rate 0.1 day-1).

The removed fermentation liquor 125 contains 25% by weight of total dry matter (dry matter - 750 kg).

The dry material includes biological material enriched with methanol and other substances.

Biological material is separated from fermentation liquor 125 in separator 126 .

Dry matter content 30% by weight from fermentation liquid 125.30m'
(dry matter = 670 kg) concentrate (biological material) 2.23
771'', 128 and 27.7 m'12 of supernatant liquid with dissolved dry matter content 0.3% by weight (dry matter - 80 kg)
7 is obtained, and the supernatant liquid 127 is returned to the biological purification system 130 of the public sewage treatment facility.

The biological material is dried on a spray dryer 132.

The amount of "main product" 134 obtained is 627 kg of powder with a moisture content of 10%, and the powder loss 133 is 5%.

The composition of the "main product" as a dry matter content is as follows: Example 2 The operation is as described in Example 1, but the sewage sludge conveyed to the heat exchanger is held at a temperature of 120° C. for 5 minutes. do.

The composition of the "by-product I" and the "main product" obtained is the same as that described in Example 1.

Example 3 ICC1earflocANI dissolved in 300% water ([
Same as described in Example 1, except that 30ky of O (organic anionic, easily degradable polyelectrolyte, product of Industrial Chemical and Equipment Company) was added for coagulation of the heat treated sewage sludge. Operate to.

The composition of the "main product" is the same as described in Example 1.

Example 4 The procedure is as described in Example 1, except that instead of methanol 1501, methanol 6001 is added to the medium daily and the fermentation is carried out semi-continuously.

The amount of 'by-product ■' and its composition are the same as described in Example 1.

Example 5 For the preparation of "by-product ■", the procedure is analogous to that described in Example 1.

For the production of the 'main product', 120 kg of ammonium hydrogen carbonate and 120 kg of ammonium nitrate are added each day to the fermentation medium instead of the 180 kg of ammonium hydrogen carbonate described in Example 1.

Further, the same procedure as in Example 1 is carried out. The amount and composition of "by-product I" are the same as described in Example 1.

Example 6 For the preparation of "by-product ■" the procedure is the same as described in Example 1.

For the production of the 'main product', 2 ky of pimelic acid (as a precursor) are added daily to the fermentation medium.

The procedure is further analogous to that described in Example 1.

Example 7 For the preparation of "By-product I", the procedure is the same as described in Example 1.

To produce the "main product", 5 kg of nicotinic acid (as a precursor) are added to the fermentation medium.

Further, the procedure is as described in Example 1.

The amount and composition of "by-product I" are the same as described in Example 1.

Example 8 Sewage sludge removal, heat treatment and separation are carried out in the same manner as described in Example 1.

Heat the concentrate to 500°C (see bottom left of the system diagram shown in Figure 2).

In this way, "by-product ■" is obtained. Regarding the preparation of the "main product", the procedure is the same as described in Example 1.

The amount and composition of the 'main product' are the same as described in Example 1.

Of course, the present invention is not limited to the above embodiments or structures, but can be implemented in many forms within the scope of the present invention.

[Brief explanation of drawings]

FIG. 1 is a system diagram of one embodiment of the apparatus of the present invention, and FIG. 2 is a system diagram showing the flow of materials in Example 2 of the present invention. 1... Digestion tank, 7... Tank, 9...
... Heat exchanger, 17 ... Sedimentation tank, 20
... Reagent dissolution device, 26 ... Medium production tank, 28 ... Decanter centrifuge, 29.
...Concentrate storage tank, 32, 58...
・Dryer, 33,59・・・Homogenizer, 3
4, 60...Bagging scale, 40...Methanol tank, 45...Fermentation tank, 49,53
...Storage tank, 50 ...Separator, 1
01... Coarse sludge, 102.121...
... Fermenter, 107,110゜128 ... Concentrate, 108,111,127 ... Supernatant liquid, 11
9... By-product ■, 124... By-product ■, 125... Fermentation liquid, 124...
Main product.

Claims (1)

[Claims] 1 a) Digested sewage sludge at a temperature of at least 80°C
b) separating the heat-treated sewage sludge into a sludge concentrate and a supernatant; C) adding a carbon atom number of 1 to 3 to the supernatant; of alcohol, at least one nitrogen-containing inorganic salt to form a medium; d) inoculating this medium with anaerobically digested sewage sludge; e) storing the inoculated medium at 26-38°C. fermentation in an anaerobic manner at temperature, f) separation of biological substances from the fermentation liquor produced during fermentation; How to treat sewage sludge. 2. The method according to claim 1 for drying biological material. 3. The method according to claim 1, wherein in step b), an inorganic or organic electrolyte, an amphoteric colloid, or an organic non-electrolyte is used as a coagulant. 4. The method according to claim 1, wherein aluminum sulfate is used as a coagulant in step b). 5. The method according to claim 1, wherein at least one of ammonium hydrogen carbonate, ammonium hydrogen phosphate, and ammonium nitrate is used as the nitrogen-containing inorganic salt. 6. The method according to claim 1, wherein pimelic acid is added as a water-soluble vitamin precursor in step C). 7. The method according to claim 1, wherein nicotinic acid is added as a water-soluble vitamin precursor in step C). 8. The method according to claim 1, wherein the biological material is concentrated and dried to a moisture content of at least 10%. 9. A heat exchanger suitable for heating and cooling the digested sewage sludge; a device for separating the heat-treated digested sewage sludge into a supernatant liquid and a sludge concentrate; the supernatant liquid is used to produce a culture medium; Purification of public sewage containing organic impurities, characterized in that it has a tank 26, a fermenter 45 suitable for the fermentation of a culture medium, and a separator 50 suitable for separating biological substances from the fermentation liquid produced in the fermenter. A treatment device for anaerobically digested sewage sludge, which is mainly generated during the process. 10. Device according to claim 9, characterized in that a tank 7 is connected before the heat exchanger for storing digested sewage sludge coming from a sewage treatment plant. 11. The heat exchanger 9 comprises at least two heat exchange units, one of which is configured as a cooling exchange unit 11 and the other as a heating exchange unit 12. The device described. 12. The apparatus according to claim 11, wherein the heat exchange units 1-11 and 12 are coil heat exchangers that can be opened and closed. 13. Apparatus according to any one of claims 9 to 12, wherein the apparatus suitable for separating digested sewage sludge into supernatant liquid and sludge concentrate is a decanter centrifuge 28. 14. Apparatus according to any one of claims 9 to 13, wherein the apparatus suitable for separating digested sewage sludge into supernatant liquid and sludge concentrate is a gravity settling tank 17. 15. Apparatus according to claim 14, in which the settling tank 17 is connected to a suitable device for supplying coagulant, and the tank 17 is provided with a device having a mixing function. 16 a settling tank 17 is present between the heat exchanger 9 and the decanter centrifuge 28, a pump 23 is integrated into the pipes 22, 24 connecting the settling tank 17 with the decanter centrifuge 28, and the suction pipe 22 is A pipe 24 branching from the upper region of the settling tank 17 and carrying the supernatant liquid is connected to it, and a pipe 25 for carrying the supernatant liquid into the storage tank 26 is connected to the supply side, on which side there is a decanter centrifuge. 16. The apparatus according to any one of claims 9 to 15, wherein a pipe 27 for carrying the supernatant liquid separated by is also connected. A supernatant liquid storage tank 17 is configured as a culture medium production tank 26, and is connected to the nitrogen source tank 17, the culture medium source tank 40, and the growth element source, and is connected to the fermentation tank 45 via a pipe 44 having a pump 43. An apparatus according to any one of claims 9 to 16. 18 storage tank 49 is present between the fermenter 45 and the separator 50.
Equipment described in Section. 19. Apparatus according to any one of claims 9 to 18, comprising an apparatus for drying and stabilizing biological material. 20 Homogenizer 59 between dryer 58 and scale 60
20. The device according to claim 19, wherein: 21 Any one of claims 9 to 20, which has a device for drying and/or heating sludge concentrate
Equipment described in Section. A 22-turn dryer 2 is connected to a decanter centrifuge 28 via a sludge concentrate storage tank 29, with a homogenizer 33 arranged below the dryer and a balance below it. Apparatus according to paragraph 21.