JP4248375B2 - Organic sludge treatment method and apparatus - Google Patents

Description

The present invention is discharged from water treatment processes such as sewage treatment plants, human waste treatment plants and food factories and chemical factories.
The present invention relates to an organic sludge treatment method and apparatus for reducing the amount of organic sludge.

In the method of biologically treating organic wastewater such as sewage, human waste and industrial wastewater, a large amount of organic sludge (excess sludge) is generated. In addition, organic sludge (raw sludge) is also generated when solids are separated in advance before biological treatment.
Conventionally, these organic sludges have been dehydrated with a dehydrator and then disposed of in landfills or incinerated. However, it is necessary to secure land for landfill, and a large amount of energy is required for incineration. In addition, there are problems such as incineration ash treatment and discharge of harmful substances such as dioxins.

From the above, after the sludge is easily biodegradable by ozone treatment, alkali treatment, acid treatment, heat treatment or ultrasonic treatment of organic excess sludge generated in the wastewater treatment process such as the activated sludge method In addition, wastewater treatment methods capable of reducing the amount of sludge to be returned to the biological treatment tank such as activated sludge treatment are being studied.
However, organic surplus sludge produced by biological treatment such as the normal activated sludge method has a sludge concentration as low as about 1% in normal solid-liquid separation using a sedimentation tank, and the sludge extracted from the sedimentation tank is directly modified. When the amount is reduced by applying, etc., a large amount of chemicals and electric / thermal energy are required, which is inefficient.
The reactor used will also be large.

Also, in wastewater treatment such as activated sludge process, sludge is agglomerated by coexisting inorganic particles such as sand, the sludge concentration in the aeration tank is increased, organic wastewater is efficiently treated, and solid-liquid separated surplus A wastewater treatment method has been proposed in which sludge is modified to be readily biodegradable with ozone, alkali or acid, and returned to the aeration tank to reduce the sludge (see, for example, Patent Document 1).
This method has the advantage that the sludge concentration in the settling tank is higher than the normal activated sludge extraction sludge concentration, so that the sludge can be reformed with a small device. It has a problem that it is dissolved by alkali treatment, acid treatment, ozone treatment, or the like, or is deteriorated and the cohesive force of sludge is reduced, and the chemical used is expensive.

Moreover, as a method for increasing the concentration of sludge, a method of treating wastewater by adding granular sludge containing anaerobic microorganisms instead of inorganic particles has been proposed (for example, see Patent Document 2).
However, the purpose of this method is to increase the sludge concentration in the aeration tank with the added substances and to efficiently treat the wastewater, so that the sludge can be simply put into the aeration tank without being easily biodegradable. It is not intended to reduce sludge by simply returning it.

JP-A-9-38681 JP 2002-336885 A

The present invention increases the concentration of organic sludge such as excess sludge produced by biological treatment such as activated sludge process by simple operation, and makes sludge efficient at low cost by a biological method that does not require chemicals. It aims at proposing the processing method and apparatus of the organic sludge which can be processed well.

The present invention has been made to achieve the above-described problems, and has been solved by the following means.
A method for treating organic sludge, in which organic sludge generated in a water treatment process or the like is supplied to an aerobic biological treatment tank in which a carrier that binds aerobic microorganisms is introduced to decompose organic matter and sludge is used as a carrier. The loaded sludge was separated together with the carrier, subjected to modification treatment with acid-producing bacteria under anaerobic conditions, and then returned to the aerobic biological treatment tank for treatment.

  Organic sludge is subjected to modification treatment with acid-producing bacteria under anaerobic conditions in advance, and then supplied to an aerobic biological treatment tank to which a carrier that binds to aerobic microorganisms is added. Acid generation under anaerobic conditions The treated product obtained by the sludge modification treatment with bacteria is solid-liquid separated and the liquid side is used as an organic raw material in the biological denitrification and dephosphorization process, and the solid is returned to the aerobic biological treatment tank for treatment. The carrier that binds to the aerobic microorganisms is also characterized by inorganic particles such as anaerobic granular sludge, coal fly ash, alumina, silica, zeolite, iron oxide, titanium dioxide, carbon or porous ceramics.

  An organic sludge treatment apparatus, an aeration tank into which a carrier that binds to aerobic microorganisms into which organic sludge generated in a water treatment process or the like is introduced, a solid liquid that is supported on the carrier and separates the sludge together with the carrier Separation tank, acid generation tank that reforms sludge separated in solid-liquid separation tank with an acid-producing bacterium under anaerobic conditions, liquid feed pipe that connects them, and processed product obtained by modification treatment of acid generation tank A liquid feeding pipe for returning to the aeration tank was provided.

An organic acid sludge is prepared in advance under anaerobic conditions, and an acid generation tank is provided for modification with acid-producing bacteria. Under anaerobic conditions, processed liquid obtained by sludge modification with acid-producing bacteria is solid-liquid separated. A solid-liquid separator, a liquid feed pipe for supplying the liquid side separated by the solid-liquid separator to the biological denitrification and dephosphorization process, and a sludge liquid feed pipe for supplying the separated solid matter to the aeration tank. Features.

According to the present invention, sludge is supported on a carrier by supplying organic sludge such as biological sludge to an aeration tank in which inorganic particles such as anaerobic granule sludge or coal fly ash as an aerobic microorganism carrier is charged. And can be solid-liquid separated as sludge with good sedimentation. For this reason, the density | concentration of sludge is raised and the modification | reformation process of sludge etc. can be performed efficiently. In addition, the modification treatment that makes sludge readily biodegradable is a biological treatment with acid-producing bacteria under anaerobic conditions, so expensive chemicals and heat treatment required for modification treatment with ozone, alkaline agents, etc. It does not require the heat and electrical energy required for sonication.

In addition, because the biological treatment is mild in the conditions of the reforming treatment, the carrier used is in a stable state and can be recycled. Moreover, the organic acid obtained by an acid production | generation process can be effectively utilized as an additive substance required for biological denitrification, such as a sewage treatment, and a phosphorus removal process.

Hereinafter, embodiments of the present invention will be described in detail. In addition, the same code | symbol is attached | subjected to the same element and the overlapping description is abbreviate | omitted. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.
FIG. 1 is a block diagram schematically showing a preferred embodiment of an organic sludge treatment apparatus according to the present invention.

Surplus extraction sludge generated in biological treatment processes such as the activated sludge method (biological sludge with high water content discharged from solid-liquid separators such as sedimentation tanks) and first sedimentation sludge in the water treatment process (organic water with high water content) Sludge) is supplied through the sludge supply pipe 100 to the aeration tank 1 in which the anaerobic granular sludge or the carrier P of inorganic particles is introduced. An oxygen-containing gas such as oxygen gas or air is supplied to the lower part of the air lift pipe 6 in the aeration tank 1 via the air feed pipe 101. In the aeration tank 1 under the aerobic condition, the introduced sludge is decomposed by the activated sludge.
Biological sludge charged in the aeration tank 1 or newly generated biological sludge is bonded to the surface of the carrier P existing in the aeration tank 1 and aggregates or granulates (granulates) using the carrier P as a nucleus.

The effluent from the aeration tank 1 is introduced into the precipitation tank 2 via the liquid feeding pipe 102, and solid-liquid separation is performed. The liquid side after the solid-liquid separation is guided and processed through a liquid supply pipe 103 to a water treatment step (not shown) for treating separately provided organic matter, nitrogen, phosphorus and the like.
Since the sludge bonded to the carrier P has good sedimentation, the concentration (about 2 to 5%) of the sludge drawn out from the bottom of the settling tank 2 is high, and about 2 to 5 compared to organic sludge such as normal activated sludge. Double. For this reason, the sludge withdrawn from the bottom of the settling tank 2 is reduced to about ½ to 1/5 of the amount of ordinary drawn sludge.

The sludge separated in the sedimentation tank 2 is drawn out through the sludge feed pipe 104, and partly returned to the aeration tank 1 through the sludge feed pipe R as necessary, and part of the sludge discharge pipe. It is discharged out of the system through 105.
The remainder is supplied to the acid generation tank 3 containing acid-producing bacteria kept under anaerobic conditions via the sludge feed pipe 106, and the sludge bound to the carrier surface of the anaerobic granular sludge or inorganic particles is organic acid or the like It is decomposed and modified.
The generated dissolved product such as organic acid and the processed product containing undecomposed are returned to the aeration tank 1 together with the carrier P through the liquid feeding pipe 107, and the solubilized product and undecomposed product such as the organic acid are contained in the aeration tank 1. It is processed. Anaerobic granular sludge and inorganic particles are reused as a carrier P for agglomerating biological sludge.

In the acid generation tank 3, the organic matter is converted into an organic acid or the like under anaerobic conditions by the sludge containing acid-producing bacteria. Therefore, the acid generation tank 3 becomes acidic with the generation of the organic acid, but is supplied to the aeration tank 1 as it is. Alternatively, it may be supplied to the aeration tank 1 after promoting the reaction by maintaining the pH in the acid generation tank at about 6 using an alkali agent.
Moreover, as temperature conditions for acid production, about 30 to 40 ° C. is suitable when using a medium temperature acid producing bacterium, and about 50 to 60 ° C. when using a high temperature acid producing bacterium. The preferable sludge residence time in the acid generation tank is about 3 to 10 days. When acid generation is performed at room temperature, for example, about 20 ° C., the sludge residence time is preferably about 7 to 20 days.

Also, as anaerobic granulated sludge thrown into the aeration tank 1, methane such as normal UASB (Upflow Anaerobic Sludge Blanket) and EGSB (Expanded Granular Sludge Blanket) What is used in the fermentation treatment process can be utilized. This anaerobic granule sludge usually has a particle size of about 1 to 7 mm, has a good sedimentation property, and has a property of binding to aerobic microorganisms. The aerobic microbial sludge adheres to the granulated sludge with better sedimentation.

When the grown granule sludge is put into the acid generation tank 3, the aerobic microorganisms bonded to the surface of the anaerobic granule sludge are decomposed by the action of acid producing bacteria and the like. Since the anaerobic granule sludge as the carrier P is hardly altered by the reforming treatment, it is returned to the aeration tank 1 and reused. In addition, as addition amount of anaerobic granule sludge, it is about 0.1-100 g / L, More preferably, it is about 1-10 g / L. In addition to anaerobic granular sludge, coal fly ash, alumina, silica, zeolite, iron oxide, titanium dioxide, carbon (activated carbon, activated coke, coke, char, etc.), porous ceramics (eg clay minerals, etc.) are calcined. Inorganic particles such as a fired product obtained can be used as a carrier.

These inorganic particles also have a property of having a great effect of aggregating sludge by combining with aerobic microbial sludge. Biological aggregates grown using the carrier P of inorganic particles as a nucleus are decomposed and modified by biological treatment in the acid generation tank 3. The carrier p of the inorganic particles that has been a nucleus retains the properties as a carrier p that becomes a core of good aggregates under the mild biological treatment conditions of the acid generation tank 3 and is stable, so return to the aeration tank. Have been used again.

A suitable particle size for these inorganic particles is about 0.1 to 1,000 micrometers, more preferably a few micrometers to a few hundred micrometers. If it is too fine, handling becomes difficult. In addition, the cohesiveness is good, but a significant improvement effect of sedimentation cannot be expected. On the other hand, when it becomes large, the effect of cohesion and granulation becomes poor. Moreover, as addition amount of an inorganic particle, it is 0.1-100 g / L, More preferably, it is about 1-10 g / L.

  In the embodiment of FIG. 1, an airlift type reaction tank is shown as a type of the aeration tank 1, but a reaction tank that supplies air, oxygen gas, or the like from almost the entire bottom of the aeration tank by a diffuser or a diffuser panel is used. You can also Further, instead of the precipitation tank 2, a solid-liquid separation tank using filtration separation, membrane separation or the like can be used.

Next, another embodiment of the present invention shown in FIG. 2 will be described.
In the embodiment shown in FIG. 2, an acid generation tank 4, which is a process for pretreating sludge to be treated, is provided in the previous stage of the aeration tank 1 in the embodiment of FIG. 1. That is, in the embodiment of FIG. 1, the sludge to be treated is directly supplied to the aeration tank 1 via the sludge supply pipe 100, but in the embodiment of FIG. 2, the sludge is previously reformed in the acid generation tank 4. Then, the liquid is supplied to the aeration tank 1 through the liquid feeding pipe 108 and processed.
Thus, if sludge is modified with acid-producing bacteria under anaerobic conditions in advance, the decomposition reaction of organic matter in the aeration tank 1 and the binding of newly generated biological sludge to the carrier are more effectively promoted. be able to.

In the embodiment shown in FIG. 2, the acid generation tank 4 is shown separately from the acid generation tank 3 provided at the subsequent stage of the precipitation tank 2, but the acid generation tanks 3 and 4 may be combined into one. Is possible. For example, the acid generation tank 3 may be omitted, and the extracted sludge from the sedimentation tank 2 of the sludge feeding pipe 106 may be supplied directly to the acid generation tank 4.

Furthermore, FIG. 3, which is still another embodiment of the present invention shown in FIG. 3, will be described. In the embodiment shown in FIG. 3, the present invention is applied to the treatment of wastewater such as sewage having a biological denitrification and dephosphorization step.
In recent years, BOD (biochemical oxygen demand) substances, N (nitrogen), and P (phosphorus) have been treated by biological treatment in advanced sewage treatment. For example, a process as shown in the lower part of FIG. 3 is known. In this treatment, first, solids are removed in a sedimentation basin A (simply natural sedimentation or agglomeration sedimentation in which a flocculant is added), and then an organic substance is removed in an oxygen-free tank (or anaerobic tank) B and nitrate or nitrite is removed. Nitrogen is denitrified, and in the aerobic tank C, ammonia nitrogen is oxidized to nitrate and nitrite nitrogen, and most of the treatment liquid in the aerobic tank C is circulated to the anoxic tank B. Denitrification is performed. The remainder of the treatment liquid in the aerobic tank C is supplied to a subsequent anaerobic tank (or anaerobic tank) D in order to remove remaining nitrate and nitrite nitrogen.

Usually, an organic substance such as methanol is added to the oxygen-free tank D. However, there is a problem that organic substances such as methanol are expensive. Next, in order to remove the remaining organic matter and phosphorus, it is treated in the aerobic tank E, and finally the sludge is separated in the final sedimentation tank F. The supernatant water of the final sedimentation basin F is sterilized (G) and then discharged from the drainage pipe 208 as treated water. The separated sludge is returned to the first oxygen-free tank B through the sludge feed pipes 209 and 211. The remaining sludge is discharged from the sludge discharge pipe 210 as surplus sludge.

In the present invention, as shown in FIG. 3, the sludge withdrawn from the first sedimentation tank A (organic sludge) is supplied to the aeration tank 1 through the sludge feed pipes 212 and 113, and the sludge is decomposed by aerobic microorganisms. At the same time, the generated biological sludge is carried on the surface of the anaerobic granular sludge or inorganic particle carrier P coexisting in the aeration tank 1.
The effluent from the aeration tank 1 is supplied to the precipitation tank 2 via the liquid feeding pipe 102 and separated into solid and liquid. If necessary, the sludge is partially returned to the aeration tank 1 via the sludge liquid feed pipe R, and the remainder is supplied to the acid generation tank 3 via the sludge liquid feed pipe 106, and then via the liquid feed pipe 107. It is supplied to a solid-liquid separation tank 5 such as a precipitation tank provided in the subsequent stage of the acid generation tank 3.

The supernatant water of the solid liquid separation tank 5 containing solubilized organic substances such as organic acids is supplied to the anoxic tank (or anaerobic tank) D through the liquid feeding pipe 109 and used as an organic source.
Part of the sludge in the solid-liquid separation tank 5 drawn out from the sludge liquid feeding pipe 110 is returned to the aeration tank 1 through the sludge liquid feeding pipes 112 and 113, and the undecomposed matter is reprocessed and at the same time the carrier P The anaerobic granule sludge or inorganic particles used as a recycle are reused. The remaining portion is discharged out of the system through the sludge discharge pipe 111 as necessary.

  In the embodiment shown in FIG. 3, a precipitation tank is generally used as the solid-liquid separation tank 5, but solid-liquid separation means using filtration separation, membrane separation, or the like can also be used. Further, the excess sludge in the final sedimentation basin F discharged through the sludge feed pipe 209 and the sludge discharge pipe 210 is supplied to the aeration tank 1 for processing, or a separate apparatus shown in FIG. 1 or FIG. Can be processed by. In the embodiment shown in FIG. 3, the supernatant water discharged through the liquid feeding pipe 103 of the settling tank 2 can be processed by supplying it to an oxygen-free tank (or anaerobic tank) B or the like.

Examples of the present invention will be described below.
Example 1
Using the apparatus shown in FIG. 1, the final sedimentation basin sludge (sludge concentration MLSS: about 8,000 mg / L) of the sewage treatment facility is supplied to the aeration tank (effective volume 100 L) at a rate of 1.5 L / hour, and the air Was supplied from the lower part of the air lift pipe at a rate of 5 L / min. The aeration tank was charged with 4 g / L of anaerobic granular sludge (particle size of about 1 to 4 mm) obtained from a methane fermentation treatment facility (UASB). The effluent water from the aeration tank was introduced into a sedimentation tank (effective volume 4.5 L) to perform solid-liquid separation, and sludge was extracted from the bottom of the precipitation tank. The concentration of this sludge was about 24,000 mg / L and the concentration of sludge was good.
Next, this sludge is supplied to an acid generation tank and reformed for 5 days under conditions of a temperature of 50 ° C., a pH of about 4 to 8, and an ORP (oxidation-reduction potential) of −150 mV or less, and anaerobic granule sludge and The acid product treated with an organic acid or the like was returned to the aeration tank for treatment. The operation was continued for 20 days.
As a result, the anaerobic granular sludge maintained its original shape even after the sludge was reformed in the acid generation tank. Moreover, there was almost no amount of sludge drawn out (sludge discharge amount) when the operation of the apparatus was stabilized, and about 100% of the input sludge amount was reduced.
Example 2

Instead of charging the anaerobic granule sludge of Example 1, it is obtained by firing inorganic particles, ie, coal fly ash, alumina, silica, zeolite, iron oxide, titanium dioxide, carbon (active coke) or clay mineral. The sludge was treated under the same conditions as in Example 1 using porous ceramics (both particle sizes were about 10 to 200 micrometers). The amount of inorganic particles added was 4 g / L.
As a result, the concentration of sludge extracted from the bottom of the sedimentation tank was about 23,000 to 26,000 mg / L, and the concentration of sludge was good. Further, even after the sludge was reformed in the acid generation tank, none of the inorganic particles was stable and stable. Moreover, there was almost no sludge discharge amount outside the system when the operation of the apparatus was stabilized, and about 100% of the input sludge amount was reduced.
Comparative Example 1

The sludge was treated under the same conditions as in Examples 1 and 2 except that the anaerobic granular sludge and inorganic particles used in Example 1 or Example 2 were not added. As a result, the concentration of the sludge extracted from the sedimentation tank was about 8,000 mg / L, and the concentration of the sludge hardly occurred. This low-concentration sludge is supplied to an acid generation tank and subjected to a reforming treatment for 1.7 days under the conditions of a temperature of 50 ° C., a pH of about 4 to 8 and an ORP of 150 mV or less. It returned to the aeration tank and processed. The operation was continued for 20 days.
As a result, since the reforming time in the acid generation tank was short, the volume reduction rate of sludge was about 30 to 40%.
Comparative Example 2

In the apparatus of FIG. 1 used in Example 1, a sludge treatment test was performed under the same conditions as in Example 1 except that an alkali treatment tank was used instead of the acid generation tank. That is, the final sedimentation basin sludge (sludge concentration MLSS: about 8,000 mg / L) of the sewage treatment facility is supplied to the aeration tank (effective volume 100 L) at a rate of 1.5 L / hour, and air is supplied from the lower part of the air lift pipe every minute. It was supplied at a rate of 5L. The aeration tank was charged with 4 g / L of anaerobic granular sludge (particle size: about 1 to 4 mm) obtained from a methane fermentation treatment facility (UASB).
The effluent water from the aeration tank was introduced into a sedimentation tank (effective volume 4.5 L) to perform solid-liquid separation, and sludge was extracted from the bottom of the precipitation tank. The concentration of this sludge was about 24,000 mg / L and the concentration of sludge was good. Next, this sludge was supplied to an alkali treatment tank, adjusted to pH 11 with sodium hydroxide, and reformed for 5 hours under the condition of a temperature of 50 ° C. The treated product obtained by the modification treatment was neutralized with hydrochloric acid and then returned to the aeration tank for treatment.
As a result, most of the anaerobic granular sludge used as a carrier when the sludge was reformed in the alkali treatment tank was dissolved, and the shape of the granular sludge initially charged could not be maintained. For this reason, even if the treated product was returned to the aeration tank, sludge aggregation did not occur, and the sludge concentrated in the sedimentation tank as the next solid-liquid separation step could not be obtained.
Example 3

Using the apparatus shown in FIG. 2, the final sedimentation basin sludge (sludge concentration MLSS: about 8,000 mg / L) of the sewage treatment facility is supplied to the acid generation tank at a rate of 1.5 L / hour, the temperature is 50 ° C., and the residence time is The reforming treatment was carried out under conditions for 5 days and then introduced into an aeration tank (effective volume 100 L), and air was supplied from the lower part of the air lift pipe at a rate of 5 L per minute. The aeration tank was charged with 4 g / L of anaerobic granular sludge (particle size: about 1 to 4 mm) obtained from a methane fermentation facility. The effluent water from the aeration tank was introduced into a sedimentation tank (effective volume 4.5 L) to perform solid-liquid separation, and sludge was extracted from the bottom of the precipitation tank. The sludge concentration was about 32,000 mg / L, and the sludge concentration was good.
Next, this sludge was supplied to the acid generation tank, and a reforming treatment was performed under conditions of a temperature of 50 ° C., a pH of about 4 to 8, an ORP of 150 mV or less, and a residence time of 3.5 days. The anaerobic granule sludge after the reforming treatment maintained the shape of what was initially introduced. The treated product containing anaerobic granule sludge and organic acid was returned to the aeration tank for treatment. The operation was continued for 20 days.
As a result, there was almost no sludge discharged outside the system when the operation of the apparatus was stabilized, and about 100% of the input sludge was reduced.

Compared with Example 1 in which sludge was directly supplied to the aeration tank, the sludge was pretreated in the acid generation tank in advance, and then the present example in which the sludge was supplied to the aeration tank was based on the carrier in the aeration tank. The sludge was well agglomerated and granulated, and a higher concentration of sludge was obtained by solid-liquid separation using a sedimentation tank as the next step.

It is a lineblock diagram showing typically one embodiment of the present invention. It is a block diagram which shows typically other embodiment of this invention. It is a block diagram which shows typically other embodiment of this invention.

Explanation of symbols

1 Aeration tank 2 Precipitation tank 3 Acid generation tank 4 Acid generation tank 5 Solid-liquid separation tank

Claims (7)

Supplying organic sludge to an aerobic biological treatment tank containing a carrier that binds aerobic microorganisms, decomposing organic matter and supporting the sludge on the carrier, separating the sludge with the carrier, anaerobic A method for treating organic sludge, comprising performing a modification treatment with acid-producing bacteria under conditions and then returning to the aerobic biological treatment tank for treatment. The organic sludge is subjected to a modification treatment with acid-producing bacteria under anaerobic conditions in advance, and then supplied to an aerobic biological treatment tank into which a carrier that binds to aerobic microorganisms is charged. Of organic sludge. Under anaerobic conditions, the treatment product obtained by the sludge modification treatment with acid-producing bacteria is solid-liquid separated, and the liquid side is used as an organic raw material in the biological denitrification and dephosphorization step, and the solid matter is the aerobic biological treatment. It returns to a tank and processes, The processing method of the organic sludge of Claim 1 or 2 characterized by the above-mentioned. Claim 1, wherein the carrier binds the aerobic microorganisms are inorganic particles anaerobic granular sludge or coal fly ash, alumina, silica, zeolite, iron oxide, titanium dioxide, carbon or porous ceramics The processing method of the organic sludge of any one of thru | or 3 . An aeration tank containing a carrier that binds aerobic microorganisms to which organic sludge is supplied, a solid-liquid separation tank that supports the carrier and separates the sludge together with the carrier, and sludge separated in the solid-liquid separation tank under anaerobic conditions An organic acid generator comprising an acid generating tank for reforming with an acid-producing bacterium, a liquid feeding pipe connecting them, and a liquid feeding pipe for returning a treatment product obtained by the reforming treatment of the acid generating tank to the aeration tank. Sludge treatment equipment. 6. The organic sludge treatment apparatus according to claim 5, wherein an acid generation tank is provided in which the organic sludge is previously subjected to a modification treatment with acid-producing bacteria under anaerobic conditions. Under anaerobic conditions, solid-liquid separation equipment for solid-liquid separation of the treatment product obtained by sludge modification treatment with acid-producing bacteria, and the liquid side separated by the solid-liquid separation equipment is supplied to the biological denitrification / phosphorus removal process An organic sludge treatment apparatus according to claim 5 or 6 , further comprising a sludge feeding pipe for feeding the separated solid matter to the aeration tank.

Images