JP2002011496A - Method and device for treating waste water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for treating waste water by which used amount of methanol is reduced while promoting removal of nitrogen and phosphor, dehydration property of excess sludge is improved, an amount of a coagulant used for dehydration is reduced, useful microorganisms of small propagating rate is held in high concentration in a reaction tank. SOLUTION: The device for treating the waste water is provided with a means 11 for executing aerobic decomposing treatment of a material 10 containing organic fibrous substances, a means 21 for executing solid-liquid separation of decomposed products obtained by the decomposing treatment and at least one treatment facility among an anaerobic treatment facility 9 and an anoxic facility 2. At least one among treatment facilities described above is provided with a means for introducing components 22 consisting mainly of liquid obtained by the solid-liquid separation of the decomposed products described above.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the treatment of sewage and industrial wastewater.

[0002]

2. Description of the Related Art Conventionally, a biological treatment method using microorganisms represented by an activated sludge method has been used for water treatment of sewage and industrial wastewater. In this biological treatment, when removing nitrogen components in wastewater, first, ammonia nitrogen is oxidized to NO ₂ -N or NO ₃ -N by the action of nitrifying bacteria, and then NO ₂ -N or NO ₃ -N Has generally been reduced to N ₂ gas. Further, the biological treatment method of phosphorus is a method of removing phosphorus in wastewater by ingesting phosphorus into microorganisms, and specifically, is performed by alternately exposing microorganisms to an anaerobic state and an aerobic state. In this case, the microorganisms exhale phosphorus using an organic substance in an anaerobic state, while the microorganisms excessively ingest phosphorus into the body using an organic substance in an aerobic state. Utilizing such properties of microorganisms, methods for biologically treating phosphorus have been developed.
In the biological treatment of phosphorus, the higher the organic matter / phosphorus ratio of the influent, the higher the phosphorus removal rate.

[0003] As described above, organic substances are useful as a reducing agent for causing a reduction reaction of a denitrification reaction, and for improving phosphorus removal efficiency. Organic substances and methanol contained in waste water have been used as such organic substances that act as reducing agents. In addition, a method has been proposed in which sludge is decomposed in an anaerobic state to generate an organic acid, and the organic acid is used as a reducing agent (hereinafter referred to as Conventional Technique 1).

[0004] In the activated sludge method, microorganisms (activated sludge) and treated water are separated in a final sedimentation basin, and a part of the settled and separated sludge is subjected to dehydration treatment after concentration. In recent years, sludge dewaterability tends to decrease due to changes in dietary habits, etc.However, as a method of improving sludge dewaterability and reducing the water content of dewatered cake, waste paper is added to sludge to be dewatered before dewatering To improve the dewatering property (Japanese Unexamined Patent Publication No. 9-2
No. 16000 (hereinafter referred to as Conventional Technique 2) has been proposed, and some are being put to practical use. Also, a method of charging a granular carrier such as waste paper or wood chips into a reaction tank (Japanese Patent Application Laid-Open No. 11-010182;
) Has also been proposed.

There has also been proposed a method of subjecting organic fibers such as cellulose to biological treatment in an anaerobic state to generate alcohol or methane (hereinafter referred to as prior art 4).

[0006]

As described above, in the conventional method for removing nitrogen from wastewater using microorganisms, when removing nitrogen components in wastewater, NO ₂ -N or NO ₃ -N is converted to N _2.
This is a method of reducing the gas. Although a reducing agent is required to cause this reduction reaction, generally only organic substances contained in wastewater are insufficient as a reducing agent.
On the other hand, when methanol is used (added) as a reducing agent, the cost of methanol is required, which causes a problem that the processing cost increases.

Further, in the technology for anaerobically decomposing sludge as shown in the prior art 1, ammonia nitrogen and phosphoric acid are generated simultaneously with the organic acid accompanying the decomposition of sludge. Since most of the organic matter generated by the biological reaction is used for treating the ammoniacal nitrogen generated, the merits of the organic matter with respect to nitrogen removal are offset, and there arises a problem that the generated phosphorus needs to be removed.

[0008] In the technique shown in the prior art 2, although the water content of the dewatered cake is reduced and the amount of the coagulant required for dewatering is also reduced, it is necessary to refine the used paper when adding the used paper. A waste paper dissolution tank must be provided. In addition, this method is a technique applied to a sludge treatment system and the like, and is effective in reducing the water content of the dewatered cake and the amount of the coagulant used for dewatering, but it is effective in removing nitrogen and phosphorus in wastewater treatment. Has no effect on

The technique shown in the prior art 3 has the advantages of improving the dewatering property and the sludge concentration in the reaction tank, but the carrier is anaerobic or anaerobic when brought into the final sedimentation tank. It becomes a state. Such a condition is undesirable for aerobic microorganisms,
Aerobic microorganisms attached to and immobilized on a carrier, such as nitrifying bacteria, are greatly damaged. Therefore, the method of the prior art 3 does not achieve the high advantage of using the carrier, that is, the high concentration of nitrifying bacteria. Further, in this method, the used waste paper and wood chips are drawn out as excess sludge and subjected to dehydration treatment, and at this time, useful microorganisms immobilized on the carrier also flow out of the reaction tank at the same time. .

The advantage of using a carrier to immobilize microorganisms is that useful microorganisms having a low growth rate are retained on the carrier, and this advantage is due to the residence time of microorganisms (or solids in a reaction tank). (Generally SR
T: Solid Retention Time). In the technique described in the prior art 3, as described above, the carrier and the suspended sludge reach the final sedimentation basin at substantially the same ratio and are drawn out at substantially the same ratio. Furthermore, in order to obtain the merit of reducing the content of the dehydrated cake as described in the prior art 3,
A relatively large amount of fiber must be introduced. Specifically, the SRT is shortened because fibrous material of about 10% or more of the generated sludge solid content when not charged is required. Therefore, the advantage obtained by using the carrier is negated in the case of the prior art 3.

A method has been proposed in which the sludge concentration (MLSS) in the reaction tank is set higher to increase the SRT. In fact, the method using the microorganism-immobilized carrier developed so far does not allow the carrier to flow out of the reaction tank,
SRT has been increased by using a carrier separation means such as a screen. However, in the prior art 3, since the carrier flows out to the final sedimentation basin and the solids load in the final sedimentation basin increases by that amount, the effect of extending the SRT by increasing the MLSS is little or negligible. In general sewage treatment, the SRT is set to about 2 to 5 days, depending on the water temperature, and is set to 3 days or more in order to retain nitrifying bacteria. In the prior art 3, the retention time of the carrier in the reaction tank is about 2 to 5 days or less, which is almost the same as suspended sludge, and the reaction time for the organic fiber to undergo the decomposition reaction is short. In addition, the organic fiber is taken out. Furthermore, the process is not such that a large amount of microorganisms having the ability to decompose organic fibers are retained. In other words, microorganisms having the ability to decompose organic fibrous materials are generally anaerobic microorganisms having a low growth rate, but aerobic reactions having a large growth rate in an aerobic state in a system having an aerobic reaction tank. Bacteria grow in large quantities. Therefore, in an aerobic state having an aerobic reaction tank, a microorganism capable of decomposing organic fibers cannot be a priority species. For this reason, since organic fiber is hardly decomposed, no organic matter is generated, and the effect of promoting nitrogen removal and phosphorus removal and the effect of reducing methanol consumption cannot be obtained.

As described above, a method of treating wastewater that promotes nitrogen removal and phosphorus removal and reduces the amount of methanol used has not yet been obtained. Furthermore, the improvement of dehydration of excess sludge, improvement of sludge separation / condensation, and reduction of the amount of flocculant used for dehydration have not been sufficiently achieved, and useful microorganisms with a low growth rate are placed in the reaction tank. At present, maintaining at a high concentration has not yet been achieved.

[0013] Accordingly, the present invention promotes the removal of nitrogen and phosphorus, reduces the amount of methanol used, improves the dewatering properties of excess sludge, improves the separation and condensation properties of sludge, and uses a coagulant for dehydration. It is an object of the present invention to provide a method for treating wastewater capable of reducing the amount and maintaining useful microorganisms having a low growth rate at a high concentration in a reaction tank.

Further, the present invention promotes the removal of nitrogen and phosphorus, reduces the amount of methanol used, improves the dehydration of excess sludge, improves the separation and condensation of sludge, and uses a flocculant for dehydration. It is an object of the present invention to provide a treatment apparatus for reducing the amount and holding a useful microorganism having a low growth rate at a high concentration in a reaction tank to treat wastewater.

[0015]

In order to solve the above-mentioned problems, the present invention provides a method for treating wastewater using a decomposition product obtained by subjecting a substance containing an organic fibrous material to an aerobic decomposition treatment. A method for treating wastewater is provided.

Further, the present invention provides a fibrous decomposition treatment step for aerobic decomposition treatment of a substance containing an organic fibrous material, and a decomposition product obtained in the fibrosis decomposition step, wherein a component mainly composed of a liquid and a solid are separated. A method for treating wastewater, comprising a step of solid-liquid separation into a component mainly composed of a liquid and a step of treating the wastewater using the component mainly composed of the liquid.

Further, the present invention comprises a means for aerobic decomposition treatment of a substance containing an organic fibrous material, and at least one treatment equipment of an anaerobic treatment equipment and an anaerobic treatment equipment, and At least one of the treatment facilities is provided with a means for introducing an aerobic decomposition product of a substance containing an organic fibrous material.

Further, the present invention provides a means for aerobic decomposition treatment of a substance containing an organic fiber, a means for solid-liquid separation of a decomposition product obtained by the decomposition treatment, an anaerobic treatment equipment, And at least one of the treatment facilities includes a means for introducing a liquid-based component obtained by solid-liquid separation of the decomposition product. A wastewater treatment device characterized by the above-mentioned features.

Hereinafter, the present invention will be described in detail.

In the method of the present invention, first, a substance containing an organic fiber is treated by the action of an aerobic organism.
By this treatment, at least a part of cellulose, which is a main component of the organic fiber, is decomposed to obtain a low-molecular-weight organic substance, and wastewater treatment is performed using the decomposition-produced organic substance.

Decomposition products obtained by decomposing and reducing the molecular weight of organic fibers are used for denitrification and dephosphorization reactions in wastewater treatment to promote nitrogen removal, improve nitrogen removal rate,
The effect of reducing methanol and the effect of improving the phosphorus removal rate can be obtained.

Furthermore, a part of the organic fiber (a part of cellulose, lignin, etc.) is dehydrated without being decomposed to the sludge treatment step, so that the efficiency of dehydration, stabilization, and the water content of the dewatered cake are improved. A reduction effect and a reduction effect of the dehydrating flocculant are obtained.

In the present invention, as the organic fiber, it is preferable to use a waste material mainly composed of organic fiber, for example, waste paper. This has the effect of reducing the cost of treating waste materials, and is also effective in terms of the current social demands of recycling and zero emissions. In addition, in the case where used paper is used, it is confirmed that even in the case where it is supplied in the form of a few centimeters in a granular form, the state in the reaction tank is so complicated that almost no prototype is left, so that the organic type is used. The input form of the fibrous material is not limited at all. However, from the viewpoint of the reaction rate, it is preferable to make the finer in advance. Whether or not to perform the miniaturization process may be appropriately determined by comprehensively judging the effect to be obtained and the cost for the miniaturization process.

Further, it is preferable to perform treatment using a microorganism having an ability to degrade cellulose as an aerobic organism or an ability to produce a cellulolytic enzyme. This is because cellulose can be efficiently decomposed by using a microorganism having cellulolytic ability or a cellulolytic enzyme.

Particularly, as the aerobic organism, Tricho
It is preferable to perform treatment using a microorganism of the genus deruma. By using this microorganism, a very high cellulose decomposition rate can be obtained.

It is preferable that, after sterilizing the organic fiber to be decomposed, at least a part of the organic fiber is decomposed to obtain a decomposition product. This can suppress the growth of microorganisms other than cellulolytic bacteria or cellulolytic enzyme-producing bacteria. Depending on the surrounding environment and the amount and type of microorganisms introduced into the reaction tank along with organic solid waste such as waste paper as a raw material, there may be no problem even in an open system. However, in the case where microorganisms other than Trichoderma are generated to some extent or more and the effect of the present invention is reduced, it may be necessary to provide a filter in the blown air line or sterilize the input material. As a sterilization method, chlorination is generally used, but ultraviolet treatment, ozone treatment, heating treatment, acid treatment, alkali treatment, high-pressure treatment, or a combination thereof can be used. These treatments are also effective as treatments for increasing biodegradability. When Trichodereuma is used, the optimal temperature of the reaction tank is from 25 ° C to 35 ° C.
It is about ° C.

At least a part of the substance containing the decomposition product of the organic fibrous material is introduced into the anaerobic and / or oxygen-free reaction vessel. Thereby, the decomposition product of the organic fibrous material can be effectively used for the denitrification reaction and the phosphorus removal reaction. In addition, when the decomposition product of the organic fibrous material is charged into the aerobic reaction tank, the decomposition product undergoes aerobic decomposition in the aerobic tank, and most of the decomposition product is decomposed into carbon dioxide and water. For this reason, there is a problem in that it is not used for a phosphorus discharge reaction in a denitrification reaction or a phosphorus removal reaction. In the present invention, since the decomposition product is introduced into the anaerobic and / or oxygen-free reaction vessel, this can be prevented. In addition, the main component of the organic fiber is cellulose. Since cellulose is a molecule composed of carbon, hydrogen, and oxygen, nitrogen and phosphorus are not included in the decomposed substance. Therefore, the problem of the prior art 1 in which the nitrogen load and the phosphorus load in the wastewater treatment increase due to the organic matter generated by the decomposition of the organic fiber can be solved.

The substance containing the decomposition product of the organic fibrous material is subjected to a separation step, and at least a part of the portion containing more liquid components is introduced into the anaerobic and / or oxygen-free reaction vessel. On the other hand, part of the portion containing more solids is introduced into the sludge treatment step. Most of the undecomposed organic fiber is contained in the portion containing more solid matter, and a part of this solid matter is not introduced into the step of treating wastewater.
T can be increased, and bacteria with a low growth rate such as nitrifying bacteria can be more stably retained.

A part of the portion containing more solids is
The organic fiber is maintained or returned in a step of decomposing the organic fiber to obtain a decomposition product. Thereby, the concentration and residence time of the organic fiber in the organic fiber decomposition tank can be increased, and a high organic fiber decomposition rate can be obtained.
In addition, this makes it possible to control the concentration and residence time of the organic fiber in the organic fiber decomposition tank.

At least a part of the step of treating the wastewater is performed in an aerobic reaction vessel, and the aerobic reaction vessel preferably contains a microorganism-immobilized carrier.
As a result, nitrifying bacteria having a low growth rate and difficult to maintain at a high concentration, such as ammonia-oxidizing bacteria and nitrite-oxidizing bacteria, can be maintained at a high concentration in the reaction vessel, so that the nitrogen component is further increased. Processing efficiency is achieved. That is, improvement of the nitrogen removal rate, stabilization of nitrogen removal, and downsizing of the reaction tank are achieved. In this case,
The amount corresponding to the input of the part containing more liquid material (more specifically, the part of the input organic matter that could not be completely separated from the part that was decomposed and re-synthesized by microorganisms and solidified (A portion where the decomposed portion flows out undecomposed), the amount of generated sludge solids increases, and the SRT is slightly shortened as compared with a case where a portion containing more liquid material is not introduced. For this reason, there is a slight disadvantage in maintaining the nitrifying bacteria in the reaction tank at a high concentration. However, by accommodating the microorganism-immobilized carrier in the reaction tank, the nitrifying bacteria are maintained at a high concentration in the carrier, and thus the efficiency of nitrogen removal as described above can be achieved.

The microorganism-immobilized carrier accommodated in the aerobic reaction vessel is preferably formed in a hollow cylindrical shape. The aerobic reaction vessel has a microbial immobilization carrier having an opening of 2 mm or more. It is desired to provide a carrier outflow prevention device such as a screen on the outflow side. Since the surface area per unit volume of the microorganism-immobilized carrier can be increased by using the hollow cylindrical microorganism-immobilized carrier, a large amount of nitrifying bacteria can be held on the carrier surface, and the shape of the carrier can be improved. The coefficient is small and the fluidity is high. Here, when a portion containing a larger amount of liquid substance (including a decomposition product of organic fibrous material and a part of undecomposed portion that cannot be completely separated by solid-liquid separation) is added to the wastewater treatment process, the organic fiber With the degradation of the quality (chemical, biological, physical), fine fibrous material is generated, and the fine fibrous material may cause blockage of the screen. Is desirably as large as possible. Practically, the stitch width of the screen is 2 mm or more, and more preferably 2.5 mm.
mm or more is preferable, but if the mesh width of the screen is increased, the size of the carrier must be increased. In this case, since the specific surface area of the carrier also decreases, it is desired to employ a hollow-shaped carrier capable of increasing the specific surface area.

A separation membrane is used for the solid-liquid separation of the effluent from the aerobic reaction vessel. Some cellulolytic bacteria or cellulolytic enzyme-producing bacteria are filamentous fungi, and solid-liquid separation by the precipitation method may be difficult.However, good solid-liquid separation is achieved by using a separation membrane, and The treated water is obtained.

[0033]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing the configuration of an example of the wastewater treatment apparatus according to the present invention. In the illustrated wastewater treatment apparatus, first, an organic fiber reaction tank influent 12 and a substance 10 containing organic fiber are introduced into an organic fiber reaction tank 11. This organic fiber reaction tank 11
Inside, the substance 10 containing organic fibers is treated by aerobic biological treatment. Further, in the present invention, as the organic fiber, a waste material mainly composed of organic fiber such as waste paper can be used.

As the aerobic organism, Trichode
It is preferable to perform treatment using a microorganism of the genus rma. By using this microorganism, a very high cellulose decomposition rate can be obtained.

It is preferable that the substance to be introduced into the step of decomposing at least a part of the organic fiber to obtain a decomposition product is introduced after sterilization. This can suppress the growth of microorganisms other than cellulolytic bacteria or cellulolytic enzyme-calculating bacteria. Depending on the surrounding environment and the amount and type of microorganisms introduced into the reaction tank along with organic solid waste such as waste paper as a raw material, there may be no problem even in an open system. However, when microorganisms other than Trichoderma are generated to some extent or more and the effect of the present invention is reduced, it may be necessary to provide a filter in the blown air line or to sterilize the input material. As a sterilization method, chlorination is generally used, but ultraviolet treatment, ozone treatment, warming treatment, acid treatment, alkali treatment, high pressure treatment, and a combination thereof can be used. Tric
The optimum temperature of the reaction tank in the case of using podoma is about 25 ° C. to 35 ° C.

The organic fibrous reaction tank 11 may contain a microorganism-immobilized carrier on which microorganisms, enzymes, and yeasts having an organic fibrous decomposing ability are immobilized.
When such a carrier is contained, "organisms having organic fibrous degrading ability" having a low growth rate can be held in the organic fibrous reaction tank at a high concentration. As a result, advantages such as downsizing of the organic fiber reaction tank and stabilization of the reaction in the organic fiber reaction tank can be obtained. Further, by these, the effect of shortening the startup period of the system and the effect of stabilizing the reaction of the system can be obtained. In the case where an immobilized carrier is used, it is particularly effective to increase the contact efficiency between the carrier and the organic fiber, and it is preferable that the organic fiber is finely divided and pulverized.

As the shape of the carrier, a hollow cylindrical shape is preferable, but other shapes can also obtain the effect. By using a hollow cylindrical carrier, there are advantages that the surface area per unit volume of the microorganism-immobilized carrier can be increased, and that the carrier has a small shape factor and high fluidity.

As the material of the carrier, any of a high molecular weight material and an inorganic material can be used. Examples of the polymer system include polyvinyl alcohol, polyethylene glycol, polypropylene glycol, polyacrylamide, polyvinyl fermal, polypropylene, polyethylene, vinylidene chloride, nylon, polyvinyl chloride, and mixtures thereof. System, sand, activated carbon, and minerals such as anthracite and zeolite. Further, wood chips or the like may be used.

On such a carrier, not only microorganisms but also enzymes may be immobilized. At that time, polyvinyl alcohol,
Polyethylene glycol, polypropylene glycol,
And an enzyme can be immobilized inside a gel such as polyacrylamide.

Further, by adding nutrients (nitrogen component, phosphorus component) and trace elements necessary for the growth of microorganisms having organic fibrous decomposing ability to the organic fibrous reaction tank 11, the efficiency can be further improved. In some cases, improvements may be observed.

An anaerobic tank 9, an anoxic tank 2, an aerobic tank 4, a sedimentation basin 7, a concentrator 15 and a dehydrator 18 are provided downstream of the organic fibrous reaction tank 11. A processing process is configured.
The order of the arrangement of the tanks and the like is not limited to the illustrated example.

The effluent of the organic fibrous reaction tank from the organic fibrous reaction tank 11 is subjected to solid-liquid separation in the solid-liquid separator 21, and a portion containing a larger amount of liquid material containing little solid matter is added to the solid-liquid separation device 21. It is separated into parts that contain more objects. Thereafter, the portion containing a larger amount of the liquid component is introduced into the anaerobic tank 9 and the anoxic tank 2, and the anaerobic tank 9 contains the inflow water (wastewater) 1 to be treated and one of the sludge from the sedimentation basin 7. The part is introduced as return sludge 13. On the other hand, for the portion 23 containing more solid matter,
A part thereof is introduced into a sludge treatment system or the like to be treated.
As will be described later, in order to increase the SRT in the organic fibrous reaction tank 11, a portion 2 containing more solid matter is used.
3 may be returned to the organic fibrous reaction tank 11. In FIG. 1, the solid matter is introduced before the dehydrating device 18, but more solid matter is supplied to the concentrating device 15, the final sedimentation basin 7, or the unillustrated first sedimentation basin and the piping for the liquid introduced thereto. Including parts can be introduced. Also,
Prior to these introductions, portions containing more solids may be treated by biological or physicochemical techniques. As a result, the quality of the return water from the sludge treatment system can be improved. Further, as shown in the figure, the concentrated separated liquid 17 from the concentrating device 15 and the dehydrating device desorbed liquid 20 from the dehydrating device 18 can also be returned to the anaerobic tank 9, but these are not necessarily required. In some cases, the concentrated separated liquid 17 and the desorbing liquid 20 are introduced into a dedicated treatment step, or may be initially introduced into a sedimentation basin or a sand basin.

The reaction proceeds in the anaerobic tank 9 under anaerobic conditions, and the effluent of the anaerobic tank 9 is introduced into the oxygen-free tank 2 together with the circulating liquid 3 which is a part of the effluent from the aerobic tank 4. . The reaction proceeds in the oxygen-free tank 2 under oxygen-free conditions, and the effluent from the oxygen-free tank 2 is introduced into the aerobic tank 4.

The aerobic tank 4 accommodates a microorganism-immobilized carrier 5, and a carrier outflow preventing (carrier separating) device 6 is provided on the outflow side of this tank. Is always retained. A part of the effluent of the aerobic tank 4 is used as the circulating liquid 3 as described above.
And the remainder is introduced into the sedimentation basin 7. As the microorganism-immobilized carrier 5 housed in the aerobic tank 4, those described above can be used. That is,
A microorganism-immobilized carrier similar to that contained in the organic fibrous reaction tank 11 can be contained in the aerobic tank 4. A screen is generally used as the carrier separation device 6, but the system is not particularly limited as long as it can separate the carrier and the effluent of the aerobic tank 4, and any device can be used. For the reason already described, the screen mesh width is practically 2 mm or more,
2.5 mm or more is preferable.

In addition, there is enough room on the site of the treatment plant,
When a large aerobic tank is provided and nitrifying bacteria can be maintained at a high concentration, it is not always necessary to use the carrier 5 in the aerobic tank 4.

In the sedimentation basin 7, the effluent introduced from the aerobic tank 4 is settled and separated to obtain sludge.
The sludge is introduced into the concentration device 15 as surplus sludge 14, and the remaining portion of the sludge is introduced into the anaerobic tank 9 as returned sludge 13. On the other hand, the supernatant liquid subjected to solid-liquid separation in the sedimentation basin 7 is discharged as treated water 8. The sedimentation basin 7 is for separating the sludge from the treated water. If the sludge can be separated from the treated water, other methods (floating separation, membrane separation, filtration, centrifugation, etc.) can be used. May be used.

In the thickening device 15 into which the excess sludge 14 has been introduced, the sludge is concentrated and introduced into the dewatering device 18 as the thickened sludge 16, and then subjected to a dewatering treatment to obtain a dewatered cake 19.
Is discharged as Further, the desorbed liquid 20 generated in the dehydration step 18 is returned and processed to the anaerobic tank 9 together with the separated liquid 17 generated in the concentration step.

The concentrating equipment 15 and the dewatering equipment 18 may be of various types, such as a centrifugal concentrator, a filtration concentrator, a floating concentrator, a belt press dehydrator, and a centrifugal dehydrator. A dehydrator, a filter press dehydrator, a rotary press dehydrator, or the like may be used. In addition, depending on the treatment facility, there is a case where the sludge treatment facility is not possessed, and the sludge is condensed or treated by a mobile sludge treatment facility, but in such a case, the effect of the present invention is maintained without any change. .

The main reactions in the above-mentioned process are a decomposition reaction and a depolymerization reaction of the organic fiber in the organic fiber reaction tank 11; a phosphorus discharge reaction in the anaerobic tank 9;
A denitrification reaction in the anoxic tank 2; and an organic matter decomposition reaction, a nitrification reaction, and a phosphorus absorption reaction in the aerobic tank 4.

The nitrogen component in the wastewater is converted from ammoniacal nitrogen or organic nitrogen to NO ₂ -N or NO ₃ -N by the action of nitrifying bacteria in the aerobic tank 4. Here, the nitrifying bacteria refer to both those that are suspended and those that are immobilized on the carrier 5. Thereafter, a part of the effluent from the aerobic tank 4 is circulated to the oxygen-free tank 2 as circulating water 3, where NO ₂ -N and NO ₃ -N are converted to N _2.
Reduced to gas. The N ₂ gas thus obtained is released to the atmosphere, whereby nitrogen components in the wastewater are removed.

As a reducing agent in this reduction reaction, an organic substance contained in the inflow water 1 is used. Further, organic matter generated in the organic fibrous reaction tank 11 and introduced into the oxygen-free tank 2 also acts as a reducing agent. Phosphorus in wastewater is removed by the following actions of microorganisms.
First, microorganisms use organic matter in the anaerobic tank 9 to exhale phosphorus in the body, and then the microorganisms that exhale phosphorus mainly absorb more phosphorus in the body than the amount exhaled in the aerobic tank 4. Thus, the phosphorus in the wastewater is removed by absorbing the phosphorus in the wastewater into the body of the microorganism.

When a reaction occurs in the anaerobic tank 9 in which microorganisms use the organic substance to exhale phosphorus in the body, the organic substance is required as an energy source. As this organic substance, an organic substance generated in the organic oxygen-containing reaction tank 11 and introduced into the anaerobic tank 9 is used.

Also, when the microorganisms that have discharged phosphorus absorb the phosphorus in the aerobic tank 4, the organic matter is required as an energy source. When the organic matter as the energy source is insufficient, a part of the organic matter, which is a decomposition product generated in the organic fibrous reaction tank 11, is introduced into the aerobic tank 4 to obtain the effect as the energy source. be able to.

In the present invention, nitrogen in wastewater is removed by the above-described redox reaction, and phosphorus in wastewater is removed by excessive intake of phosphorus. Furthermore, in the present invention, organisms proliferate with a biological reaction utilizing a substance produced by the decomposition of organic fibrous materials. At this time, the microorganisms ingest the phosphorus compounds and nitrogen compounds in the water. Thus, the phosphorus concentration and the nitrogen concentration in the treated water are further reduced.

In the organic fiber reaction tank 11, at least a part of the organic fiber is decomposed, but undecomposed organic fiber remains. In the present embodiment, decomposition products of organic fibrous materials generated in the organic fibrous reaction tank 11 and undecomposed products are separated. Specific examples of the separation means include centrifugation, flotation, membrane separation, precipitation concentration separation, and filtration separation. Further, as a simple separation method, 1) gently agitate the organic fiber reaction tank, 2) provide an organic fiber outflow prevention device at the outlet of the organic fiber reaction tank, and 3) provide an organic fiber outflow prevention device. There is also a method in which the organic fiber is settled or floated by using the system fiber reaction tank as a batch operation. A coagulant may be added during solid-liquid separation. When solid-liquid separation is carried out, it is divided into a part containing more liquid components and a part containing more solid components, and contains a lot of liquid components in the water treatment step, that is, components useful for denitrification reaction and phosphorus removal reaction. Parts can be introduced. Furthermore, by introducing a portion containing a large amount of solids into a sludge treatment system or the like, a portion containing a large amount of solids is not introduced into the water treatment system, so that the SRT in the water treatment system can be increased, and nitrifying bacteria can be prevented. Such a useful microorganism having a low growth rate can be stably maintained.

If the function of the water treatment system is not impaired even if part or all of the portion containing a large amount of solids is introduced into the water treatment system, the portion containing a large amount of solids is also added to the water treatment system. It can also be introduced. Further, the decomposition product of the organic fibrous material and the undecomposed substance (a mixture of the liquid component and the solid component) may be introduced into the water treatment system without performing the solid-liquid separation. Further, by reducing the amount of water flowing into the organic fibrous reaction tank, the reaction in the organic fibrous reaction tank may be in a state close to a solid culture system, in which case the reactant in the organic fibrous reaction tank is solid-liquid. What is necessary is just to introduce | transduce into a water treatment system, without separating.

Further, since the undecomposed organic fiber improves the dewatering property of the sludge, the water content of the dewatered cake 19 from the dewatering device 18 is reduced, and the cost of auxiliary fuel for incinerating the dewatered cake is reduced. There is also an advantage that the amount can be significantly reduced and the amount of recovered energy increases. An improvement in dewatering properties and a decrease in the water content of the dewatered cake reduce the volume of the sewage sludge cake, and thus have an advantage in terms of handling such as transportation costs. In addition, there is a merit that the amount of the coagulant for dehydration can be reduced as the dehydration property is improved.

In the present invention, the shape of the organic fibrous material 10 introduced into the organic fibrous reaction tank 11 is not particularly limited, and may be any of a granular shape, a powdery shape, a thread shape, and a paper strip shape. . From the viewpoint of reaction efficiency and reaction rate, although organic fibers are more advantageous as finer,
In this case, cost, maintenance for treatment, etc. are required. Therefore, the input form of the organic fiber may be appropriately determined in consideration of the necessity and effect. In addition, as organic fiber, waste paper (shredder waste generated in offices and the like, shredder waste compressed and molded, waste paper molded into granules, etc.), wood chips (including construction waste material), rice hulls, Garbage and the like and a mixture of two or more of them can be used. However, kitchen garbage and the like having a high concentration of nitrogen and phosphorus components is not preferable because the effects of the present invention are reduced. In addition, as long as the concentration of organic fibers and the concentration of organic substances are high and the concentrations of nitrogen and phosphorus components are low, waste and wastewater generated from factories and offices can be used as raw materials. In the case of used paper, if it is going to be recycled as paper, it is necessary to separate it in advance, but in the present invention, separation is not particularly necessary, and it is currently the most difficult to separate it and it is difficult to reuse it as paper. Yes, you can also use so-called mixed waste paper. The high quality paper portion of the mixed waste paper contains a large amount of cellulose, which is decomposed and degraded to low molecular weight and used for nitrogen removal and phosphorus removal. On the other hand, the low-quality paper portion contains a large amount of hardly decomposable components such as lignin, while the non-decomposed portion contributes to the improvement of sedimentation, concentration and dewatering of sludge.

Further, by pre-treating the organic fiber before being decomposed and reduced in molecular weight in the organic fiber reaction tank 11, the reaction efficiency and the reaction speed can be improved. Examples of the pretreatment include an acid treatment, an alkali treatment, an ozone treatment, a peroxide treatment, a temperature treatment, an ultrasonic treatment, a pressure treatment, and a combination thereof. Whether or not to perform these processes can be appropriately determined by comprehensively judging the processing costs, the necessity of maintenance and management for the processes, the effects, and the like.

The average residence time of the organic fibrous material 10 in the organic fibrous reaction tank 11 is 0.5 days or more, preferably 1 day or more. This is because the growth rate of microorganisms capable of decomposing organic fiber is low, and such a residence time is required to keep such microorganisms in the reaction tank at a high concentration. This is because the decomposition rate of the system fiber is low and a long reaction time is required.

In order to increase the residence time of the organic fibrous material 10 in the organic fibrous reaction tank 11, the following method can be adopted. 1) The organic fibrous reaction tank 11 is gently stirred, and the organic fibrous reaction tank 1 is stirred.
2) Provide an organic fiber outflow prevention device at the outlet of the organic fiber reaction tank 11 to reduce the outflow of decomposition products and undecomposed organic fibers from 1) 3) Organic fibers 4) The organic fibrous reaction tank 11 adjusts (reduces) the amount of the organic fibrous reaction tank inflow liquid 12 into the reaction tank 11 or adjusts (reduces) the sludge withdrawal amount.
As a batch operation to precipitate or float the organic fibrous material, and then extract the content from a portion containing a larger amount of the liquid component and a lower concentration of the solid component. 5) Part of the portion 23 containing a larger amount of the solid material Return to the organic fibrous reaction tank 11,
Such a method.

As a method of 1) to stir the organic fibrous reaction tank 11 gently, a mechanical stirrer is generally used, but gas may be blown into the tank for stirring. Generally, the rate of biological decomposition of organic fibrous materials is more anaerobic (reaction in the absence of oxygen) or anoxic reaction (reaction in the absence of dissolved oxygen) than aerobic reaction. (Reaction in the presence of oxygen). Therefore, when agitating by injecting a gas, a gas having a low oxygen concentration is injected; the amount of the injected gas is suppressed to a minimum that can be agitated; the gas is intermittently injected; It is desired that the inside of the organic fibrous reaction tank 11 be maintained in an anaerobic state by a low apparatus (for example, an apparatus that generates coarse bubbles).

As a method for providing the organic fiber outflow prevention device at the outlet of the organic fiber reaction tank 11 in 2), a screen is used when the organic fiber is in a lump such as a granular form. it can. Further, a sedimentation or flotation facility can be provided by utilizing a specific gravity difference.

3) Adjustment (reduction) of the amount of the inflow water 12 into the organic fibrous reaction tank 11, and reduction of the molecular weight of the organic fibrous and undecomposed components from the organic fibrous reaction tank 11. In order to adjust (reduce) the amount of extraction of sludge, it is necessary to perform an extraction operation at a stage where sludge is accumulated to some extent in the organic fibrous reaction tank. This is because undecomposed organic fibers generally accumulate in the organic fiber reaction tank 11. In addition, it is also possible to increase the residence time of the organic fiber in the organic fiber reaction tank 11 by reducing the input amount of the inflow water 12 or setting the sludge withdrawal amount lower. is there.

When persistent organic substances accumulate in the organic fibrous reaction tank 11, it is necessary to remove them. Basically, it may be sent to the solid-liquid separation device 21 by increasing the stirring speed or the like. As other operations for extracting sludge containing undecomposed organic fibrous materials, for example,
A method of directly pulling out the hardly decomposable organic matter from the organic fibrous reaction tank 11 can be adopted, and more specifically, it can be provided with a pipe or with a vacuum car. The extracted sludge is introduced into the sedimentation basin 7 or the concentration device 15. Further, although not shown, the extracted sludge can be first introduced into the sedimentation basin.

In the case where the sludge withdrawn is not particularly particulate, it may be introduced into the anaerobic tank 9, the oxygen-free tank 2, or the aerobic tank 4. In some cases,
The balance between the mass of the organic fibers fed into the organic fibrous reaction tank 11 and the amount of solids containing the organic fibers flowing out of the organic fibrous reaction tank 11 is not required, and there is no need to extract sludge. Sometimes. In addition, by adjusting the stirring intensity of the organic fibrous reaction tank 11, solids containing organic fibrous material can be discharged from the organic fibrous reaction tank 11, whereby the organic fibrous reaction tank 11 can be discharged. It is possible to adjust the amount of extracted sludge and the residence time of the organic fiber in the organic fiber reaction tank 11.

The amount of the organic fibrous material 10 introduced into the organic fibrous reaction tank 11 varies depending on the quality of the inflow water 1, the amount of water, and the required quality of the treated water 8. In general,
When the desired nitrogen concentration or phosphorus concentration of the treated water is low; when the BOD / nitrogen ratio or BOD / phosphorus ratio of the influent water is small; It is necessary to increase the amount of the fibrous material 10. When treating general sewage, the input amount is 1m of incoming sewage.
^{It is} about 10 to 500 g per ³ pieces. The type of organic fiber, the reaction conditions, or the input amount of organic fiber calculated from the inflow water quality and the required treated water quality and the organic fiber input amount calculated from the required water content of the dehydrated cake must match. Is preferred. That is, if the decomposition rate of the organic solid waste is high, the amount of the methanol-substituted organic substance increases, but the effect of reducing the water content of the dehydrated cake is diminished. on the other hand,
If the decomposition rate of the organic solid waste is low, the pattern is reversed.

Here, it is necessary to match the amount of the organic fibrous decomposed product required for the synthesis of the methanol substitute organic material with the residual amount of the organic fibrous material required for improving the dehydration property. That is, after all, controlling the decomposition rate of the organic fiber to a predetermined value. Operating factors and controlling factors for controlling the decomposition rate of organic fiber to a predetermined value include temperature, degradability of raw materials, type and concentration of microorganisms,
If the reaction time is constant, the temperature is constant, and the raw materials are constant, the most easily controllable item is the reaction time. The reaction time is a function of the reaction rate, the reaction tank volume, and the feed rate of the raw materials (organic fiber and water) to the reaction tank. The volume of the reaction tank and the amount of the raw materials (organic fiber and water) to be fed into the reaction tank may be determined from the amount (speed) of the undecomposed organic fiber. If the temperature or the composition of the raw material can be changed, these can also be added to the control factor. further,
As described above, when performing solid-liquid separation of the contents of the organic fibrous decomposition reaction tank, the residence time on the liquid side and the residence time on the solid matter side can be controlled independently. The organic fiber input amount calculated from the type, reaction condition, or inflow water quality and the required treated water quality can be substantially matched with the organic fiber input amount calculated from the required water content of the dehydrated cake.

For the decomposition of organic fibrous materials, it is preferable that microorganisms and cellulolytic enzymes (cellulase, etc.) capable of decomposing organic fibrous materials are present. It is desired to supply to. When a part of the returned sludge is introduced into the reaction tank 11 for decomposing organic fibers as described above, if microorganisms capable of decomposing organic fibers are contained therein, In some cases, it is not particularly necessary to introduce enzymes and microorganisms into the reaction tank. However, it is effective to add these at the start of the reaction in order to quickly start the reaction. Whether to add only at the start of the reaction, whether to always add the addition, not to add, or how much the amount to add depends on the regional characteristics, the presence or absence of inflow into the factory wastewater, and the like, as described above. In addition, the conditions for adding enzymes and microorganisms vary depending on the required degree of molecular weight reduction of organic substances and the water content of the dehydrated cake. Therefore, the addition of enzymes and microorganisms can be determined as appropriate in consideration of the stability of the reaction, the obtained reaction rate, and the like, and the economic efficiency. However, in general, in the open system, a variety of heterotrophic aerobic bacteria appear and further degrade cellulose degradation products. It is preferred to charge later.

Note that the flow of FIG. 1 shows an example of the wastewater treatment apparatus of the present invention, and the present invention is not limited to this flow. The anaerobic tank 9, the anaerobic tank 2, the aerobic tank 4, the aerobic tank circulating liquid 3, the sedimentation basin 7, and the returned sludge 13 in FIG. 1 constitute a water treatment process. It is a typical sewage advanced treatment flow called the method. Even if the water treatment step is replaced with a treatment method other than the anaerobic anoxic aerobic method, the effects of the present invention can be obtained with almost no change. For example, when the flow of the water treatment step is the standard activated sludge method, the standard activated sludge method itself does not assume the flow of nitrogen removal or phosphorus removal due to excessive intake of phosphorus. The effect of the promotion effect is weakened. However, even in this case, a biological reaction utilizing substances produced by the decomposition of the organic fibrous material occurs, and the organism grows accordingly. At this time, the microorganisms ingest the phosphorus compounds and nitrogen compounds in the water into the living body. I do. Thus, the phosphorus concentration and the nitrogen concentration of the treated water are reduced. further,
All effects such as a reduction in the amount of methanol used, a reduction in the amount of a coagulant for dehydration, and an improvement in sludge separation / concentration properties are maintained without any change.

Further, the water treatment process in the apparatus shown in FIG. 1 includes a circulation type nitrification denitrification method, an anaerobic-aerobic method, a Badenho method, a modified Badenho method, a step-flow type nitrification denitrification method, a nitrification-endogenous denitrification method, Almost all biological treatment flows such as the anaerobic-nitrification-endogenous denitrification method and the like can be replaced by the flow of the carrier charging method. In any case, the effect of the present invention is almost maintained. When these methods are adopted, the effluent of the organic fibrous reaction tank is discharged from a low-dissolved oxygen tank such as an anaerobic tank or an anoxic tank in the flow, or a tank that does not blow oxygen, or a microaerobic tank. At least one can be introduced. As described above, a part of the effluent of the organic fibrous reaction tank may be introduced into the aerobic tank in order to promote the absorption of phosphorus. In addition, when the water treatment step is performed in a batch operation, it is preferable to introduce the effluent of the organic fibrous reaction tank during a time period when the dissolved oxygen concentration is low, but it is not always necessary to limit the time period to only this time period.

The present invention basically promotes nitrogen removal and phosphorus removal by aerobically decomposing organic fibers in the organic fiber reaction tank 11 and utilizing the decomposition products in a biological reaction. It is intended to improve the separation, concentration and dewatering properties of sludge by utilizing undegraded organic fibrous substances, and all treatment flows based on such a concept are included in the scope of the present invention.

Depending on the type of organic fibrous material to be decomposed, a biological method may be installed in the first stage, and a chemical or physical means such as ozone blowing may be installed in the second stage, or the order may be reversed. It is also possible to Organic fibrous reaction tank 1 that decomposes and decomposes organic fibrous materials
It is also possible to provide a plurality of 1s.

Further, the pipe introduced into each tank does not need to be directly introduced into each tank, but can be obtained by combining with the pipe introduced into the tank, mixing with the liquid, and then putting the mixture into the tank. The effect remains the same.

[0076]

The present invention will be described in more detail with reference to specific examples and comparative examples.

First, in the flow shown in FIG. 1, a device for introducing an effluent (a portion containing more liquid components) from the solid-liquid separator 21 into the anaerobic tank 9 and the oxygen-free tank 2 by half is constructed. This was used to treat wastewater, and the result was set to Example 1. The effluent from the solid-liquid separator 21 (the portion containing more solid matter) was introduced before the dehydrator 18.

In the first embodiment, specific gravity 1.01, length 5 mm, outer diameter 4 mm, inner diameter 3
The hollow cylindrical carrier 5 made of expanded polypropylene having a diameter of 7 mm is accommodated at 7% on the basis of the true volume, and the carrier outflow preventing device 6 has a mesh width of 2.
A 5 mm wedge wire screen was installed at the outlet of the aerobic tank 4. In addition, a continuous centrifugal separator was used as the solid-liquid separator 21.

An apparatus similar to that of the above-described embodiment 1 was constructed except that the microorganism-immobilized carrier 5 was removed from the aerobic tank 4, and the waste water was treated using the same apparatus. And

In Examples 1 and 2, the volume of the organic fibrous reaction tank 11 was 5 liters.
At the start of the experiment, the organic fiber reaction tank 11
Separately, a Trichod cultured in a bioreactor
A microorganism of the genus erma was inoculated.

Further, in order to promote the removal of nitrogen and phosphorus and to compare the sludge separation / concentration / dewatering properties, waste water was treated in the following manner as Comparative Examples 1 to 4.

The wastewater is treated by the anaerobic anoxic aerobic method,
Comparative Example 1 was used. This method corresponds to the case where the organic fibrous reaction tank 11 and the solid-liquid separator 21 are not installed in the second embodiment.

In the anaerobic anoxic aerobic method, waste water was treated by a method of mixing waste paper that had been made fine before dehydration, to obtain Comparative Example 2. This method corresponds to a flow in which Conventional Technique 2 is further applied to the method of Comparative Example 1 which is an anaerobic anoxic aerobic method.

First, a mixed sludge of the sedimentation basin sludge and the excess sludge was subjected to acid fermentation, and the wastewater was treated by a method of half-feeding the mixed sludge into the anaerobic tank and the oxygen-free tank to obtain Comparative Example 3. The aerobic tank 4 does not contain a carrier. This method is a flow in which Conventional Technique 1 is applied to an anaerobic anoxic aerobic method.

In Comparative Example 4, waste water was treated by a method employing an anaerobic oxygen-free aerobic method in the reaction tank in the prior art 3 in which granular waste paper was charged into the reaction tank. The aerobic tank 9 contains no carrier.

The raw water used in the above Examples 1 and 2 and Comparative Examples 1 to 4 was the first settling pond effluent of a domestic wastewater treatment plant, and the measured values shown below were measured 10 times in 10 months. It is the average of the measurements. Items common to each treatment include inflow water quality, water temperature, inflow water flow rate (100 L / hr),
Oxygen-free tank 2 volume (300 L), aerobic tank 4 volume (200 L), final sedimentation tank water area load (100 m /
Day), Circulating water ratio (200%), Returned sludge ratio (50%)
It is. The amount of sludge withdrawn was set so that the aerobic tank 4 had a sludge concentration of 3000 mg / L only in Comparative Example 4, and in other cases (Examples 1, 2 and Comparative Examples 1 to 3) 4 was carried out so that the sludge concentration became 2000 mg / L.

Waste paper is used as the organic fibrous material 10. Specifically, shredder dust in an office is 2 mm.
Those cut into corners were used. In Examples 1 and 2 and Comparative Example 4, 3.6 g / hr of waste paper was added to the organic fibrous reaction tank 11, and in Comparative Example 2, 1.8 g / h.
r equivalent waste paper was added before dewatering. In Examples 1 and 2, waste paper was dispersed in treated water so that the concentration of waste paper was 3%, and sodium hypochlorite solution was added to sterilize the chlorine and then added to the organic fiber reaction tank 11. .

In each Example and Comparative Example, the total length was 2
A rectangular stirring blade having a height of 8 cm and a height of 8 cm is placed in the reaction tank 11.
It is installed from the top so that there is a clearance of 5 cm from the bottom, and the inside of the reaction tank is almost uniformly stirred 35r
Stirred at pm. Further, air treated with an air filter was blown into the air diffuser ball provided at the bottom to maintain the dissolved oxygen concentration at 3 mg / L or more.

After treating wastewater according to Examples 1 and 2 and Comparative Examples 1 to 4, the quality of the treated water, the sedimentation / separation of sludge, and the water content of the dewatered cake were examined. The results obtained are shown in Table 1 below. Put together.

The dewatering property of the sludge was determined by determining the appropriate amount of the polymer flocculant to be added by a jar test, and then transferring the sludge after flocculation and gravity dewatering between filter cloths of a belt press dehydrator using a pressure tester. After dehydration under pressure at 1.5 kg / cm ² for 1 minute, the moisture content of the dehydrated cake was measured and evaluated.

[0091]

[Table 1]

As shown in Table 1, in Examples 1 and 2, the treated water quality was clearly excellent in both TN and TP, and the water content of the dehydrated cake was also a low value. These effects are as follows: the introduction of organic substances accelerated the denitrification and dephosphorization reactions, the fact that only organic substances were added and the nitrogen component and the phosphorus component were not added, and undecomposed organic substances had a favorable effect on the dewatering properties of sludge. It has been brought about by the features of the present invention such as giving.

In particular, the microorganism-immobilized carrier 5 is placed in the aerobic tank 4.
In this case, NH ₄ —N was completely removed as shown in the results of Example 1 containing NH ₄ -N
NO _x -N generated by the oxidation of
This is because nitrification bacteria were maintained at a high concentration by the introduction of the microorganism-immobilized carrier 5, and the denitrification reaction was promoted by the addition of organic substances generated by the decomposition of organic fibrous materials.

In Example 2, although the removal of NH ₄ —N was not complete, the removal reaction (removal of NO _x —N) generated due to the addition of the organic matter generated by the decomposition of the organic fiber was added. Nitrogen reaction) is promoted. For this reason, NO _x -N in the treated water becomes a small value, and as a result, TN
Is a small value following the first embodiment.

On the other hand, in each of Comparative Examples 1 to 4,
The effect as in the present invention has not been obtained. In Comparative Example 1,
Both TN and TP in the treated water are high, and the water content of the dehydrated cake is also high. In Comparative Example 2, although the water content of the dewatered cake is slightly improved, the quality of the treated water is not much different from Comparative Example 1.

In Comparative Example 3, the effect of the addition of the organic matter appears in that there is almost no NO ₃ -N in the treated water, but the values of TN and TP are not necessarily low. This is because the nitrogen component and the phosphorus component generated by the decomposition of sludge flow into the treatment system together with the organic matter.

In Comparative Example 4, only a slight effect was obtained in reducing the water content of the dehydrated cake, and the quality of the treated water was almost the same as in Comparative Example 1, and there was no significant change.

[0098]

As described above, according to the present invention, nitrogen removal and phosphorus removal are promoted, the amount of methanol used is reduced, the excess sludge is dewatered, the amount of coagulant used for dehydration is reduced. The present invention provides a method for treating wastewater, which can reduce the amount of microorganisms and keep useful microorganisms having a low growth rate at a high concentration in a reaction tank. According to the present invention, the use of methanol is reduced while promoting the removal of nitrogen and phosphorus,
In addition, by improving the dewatering properties of excess sludge, improving the separation and condensation properties of sludge, and reducing the amount of flocculant used for dewatering, the useful microorganisms with a low growth rate are retained at a high concentration in the reaction tank, A processing device for performing processing is provided.

In the present invention, a part of organic fibers such as waste paper containing almost no components such as nitrogen and phosphorus is decomposed, and the generated decomposition products are used for removing nitrogen and phosphorus in wastewater treatment. Since it can be used, advanced treatment of wastewater (nitrogen and phosphorus removal) is achieved, and undecomposed organic fibers improve the separation, concentration and dewatering properties of sludge. Also,
As compared with the method of adding methanol, there is obtained an advantage that the processing cost can be reduced. Further, when the microorganism-immobilized carrier is accommodated in the aerobic tank, the treatment efficiency of the advanced treatment is improved (the removal rate is improved and the volume of the reaction tank is reduced), and the treatment is stabilized. In addition, the use of waste paper, which is waste, is effective in terms of effective use of resources and waste disposal, and its industrial value is great.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a configuration of an example of a wastewater treatment apparatus according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Inflow water 2 ... Oxygen-free tank 3 ... Aerobic tank circulating liquid 4 ... Aerobic tank 5 ... Carrier 6 ... Carrier outflow prevention device 7 ... Sedimentation basin 8 ... Treated water 9 ... Anaerobic tank 10 ... Input organic fiber 11 ... Organic fiber reaction tank 12 ... Organic fiber reaction tank inflow liquid 13 ... Returned sludge 14 ... Excess sludge 15 ... Concentrator 16 ... Concentrated sludge 17 ... Concentrator desorbed liquid 18 ... Dehydrator 19 ... Dewatered cake 20 ... Separation liquid of dehydrator 21 ... Solid-liquid separator 22 ... Part containing more liquid components after solid-liquid separation 23 ... Part containing more solid components after solid-liquid separation

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C12R 1: 885) B09B 3/00 ZABA (72) Inventor Shigeki Fujiwara 1-1-2 Marunouchi, Chiyoda-ku, Tokyo No. Nippon Kokan Co., Ltd. (72) Inventor Kenichiro Mizuno 1-1-2 Marunouchi, Chiyoda-ku, Tokyo F-term (in reference) 4B029 AA02 BB08 CC03 DA03 4B065 AA70X BA22 BB26 BC05 BC22 BD14 CA55 4D004 AA12 CA19 CA20 CC07 4D040 BB05 BB13 BB32 BB42 BB57 BB66 BB72 BB82 BB93

Claims (10)

[Claims] 1. A method for treating wastewater, comprising treating a wastewater using a decomposition product obtained by subjecting a substance containing an organic fiber to an aerobic decomposition treatment. 2. The method for treating wastewater according to claim 1, further comprising a fibrous decomposition treatment step of aerobic decomposition treatment of the substance containing the organic fiber substance. 3. A fibrous decomposition treatment step of aerobic decomposition treatment of a substance containing an organic fibrous material, and a decomposition product obtained in the fibrous decomposition step is mainly composed of a liquid-based component and a solid. Comprising a step of solid-liquid separation into components
A method for treating wastewater, wherein the treatment of wastewater is performed using the liquid-based component. 4. The method for treating wastewater according to claim 1, wherein the substance containing the organic fiber is waste paper. 5. The method according to claim 5, wherein the fibrous decomposition step comprises the step of:
The method for treating wastewater according to any one of claims 2 to 4, wherein the method is a step using an enzyme. 6. The method for treating wastewater according to claim 5, wherein the microorganism is a microorganism of the genus Trichoderma. 7. The method for treating wastewater according to claim 5, wherein the substance containing the organic fibrous material to be decomposed is sterilized and then introduced into the fibrous decomposing step. . 8. A system for aerobic decomposition of a substance containing an organic fiber, and at least one of an anaerobic treatment facility and an anoxic treatment facility, and
At least one of the treatment facilities is provided with a means for introducing an aerobic decomposition product of a substance containing an organic fibrous material. 9. A means for aerobic decomposition of a substance containing an organic fibrous material, a means for solid-liquid separation of a decomposition product obtained by the decomposition, and an anaerobic treatment facility and an anoxic facility And at least one of the processing facilities is provided with a component introducing means mainly composed of a liquid obtained by solid-liquid separation of the decomposition product. Wastewater treatment equipment. 10. The wastewater treatment apparatus has a sludge treatment facility, and the sludge treatment facility removes a solid obtained by solid-liquid separation of an aerobic decomposition product of a substance containing an organic fiber. 10. The wastewater treatment apparatus according to claim 9, further comprising means for introducing a main component.