JP6546688B1 - Method and apparatus for treating organic wastewater or sludge - Google Patents

Abstract

An organic wastewater or sludge treatment method and treatment apparatus capable of improving treatment efficiency in a treatment process and a treatment system as a whole are provided. An organic wastewater or sludge treatment method for treating organic wastewater or sludge using microorganisms to treat organic components, wherein the organic wastewater or sludge is treated with an aerobic microorganism. Biodegradable organic fiber material is added to wastewater or sludge, or to organic wastewater or sludge after aerobic treatment, and anaerobic to sludge with biodegradable organic fiber material added Anaerobic treatment using microorganisms is performed, and solid-liquid separation treatment is performed before and / or after anaerobic treatment, and biodegradable organic fiber material is added to at least one treatment of anaerobic treatment and solid-liquid separation treatment. A method of treating organic wastewater or sludge comprising the further addition. [Selected figure] Figure 1

Description

  The present invention relates to a method and apparatus for treating organic wastewater or sludge.

  Conventionally, in a water treatment apparatus represented by the activated sludge method, in order to increase the concentration of microorganisms in the treatment tank and improve the separability between the activated sludge and the treated water, the contact filter medium or fluid carrier for immobilizing microorganisms is treated with the treatment tank. Many methods have been adopted for introducing inside. When the amount of activated sludge fixed to the contact filter medium or fluid carrier is increased more than necessary, part of the activated sludge is peeled off from the filter medium or carrier by an operation such as backwashing and discharged out of the system as excess sludge and dewatered. Be done. Plastics, activated carbon, anthracite, polyethylene glycol and the like are used as the contact media and the fluid carrier.

  Also, in recent years, excess sludge generated in water treatment equipment is introduced into anaerobic treatment processes such as methane fermentation treatment, and organic matter in the sludge is converted to combustible gas such as methane or hydrogen and recovered, power generation, sale of electricity, etc. Cases are increasing. The sludge after anaerobic treatment is subjected to solid-liquid separation treatment such as dehydration treatment to reduce solids in the sludge, and is often carried out of the system in the form of dewatered cake, incinerated ash or the like.

  When considering the optimization of the whole organic wastewater or sludge treatment process, (1) treated water quality in water treatment system, (2) solid-liquid separation of activated sludge and treated water, (3) filter medium to which microorganisms adhere And five evaluation items such as durability of the carrier, bioremovability and cost, (4) recoverable amount of combustible gas in methane fermentation tank, and (5) solid-liquid separation of sludge after anaerobic treatment It is listed as a necessary evaluation item to consider.

  With regard to the five evaluation items, it is desirable that the treated water quality in (1) be stabilized at BOD, COD, phosphorus, nitrogen, etc., which are the components to be treated, below the discharge regulation value. It is desirable that solid-liquid separation between activated sludge and treated water in (2) should be stable and unlikely to be affected by seasonal fluctuation, water quality fluctuation and the like, and be controlled so as not to cause bulking and the like. In the filter medium and carrier of (3), microorganisms are likely to be attached, and at the time of backwashing, the microorganisms are likely to be exfoliated, which is durable, and it is desirable that the cost be low. It is desirable that the flammable gas recovery amount in (4) be as large as possible, and the power generated by the recovered gas will be greatly affected by the profit because the power company will buy it at the relatively high purchase price decided by the fixed price purchase system. . The sludge after anaerobic treatment represented by anaerobic digestion sludge (5) is often dewatered, but it was dewatered as the amount of polymer flocculant used was small. The lower the moisture content of the cake, the lower the processing and disposal costs are desirable.

  In Patent Document 1, a particulate carrier having a large proportion of organic fibers is contained in a treatment tank in which microorganisms are brought into contact with and mixed with the raw water to be treated, and after a predetermined residence time, at least one of the carriers is contained. An example is described in which the part is subjected to solid-liquid separation and taken out of the system as excess sludge together with the adhered microorganisms to be dehydrated. A method has been proposed that uses cellulose-based waste as a carrier. In this method, a cellulose-based material is used as a carrier for immobilizing transient microorganisms, and at the same time, it is used as a material for improving the dewatering property in the subsequent dehydration processing step as solid-liquid separation. There is no suggestion on the efficiency of the entire system, including the degradation rate in anaerobic treatment of cellulosic materials, rather than the process premised on performing

  Further, in Patent Document 2, organic wastewater before biological treatment is passed through a sieving body, and the permeated water of the sieving body is subjected to a biological treatment to obtain a solid which has not permeated through the sieving body, that is, a fiber having a large particle diameter. There has been proposed a method of dewatering treatment by adding excess sludge to surplus sludge generated by biological treatment. In this method, solid matter with a relatively large particle size, such as a fiber component derived from toilet paper in raw water, is added to excess sludge at the stage prior to the dewatering treatment step without passing through biological treatment to improve the dewaterability. In the invention described in Patent Document 2, the efficiency of the organic fiber material in consideration of three aspects of the bioimmobilization carrier, the organic matter source for anaerobic treatment, and the organic matter source for improving the dewaterability is also described. There is no description or suggestion on the method of addition.

Japanese Patent Application Laid-Open No. 11-10182 JP 2001-219186 A

  The existing treatment facility is designed and calculated based on the planned water quality and the planned water volume for the treatment target material at the initial stage of plant design, and the plant is configured, so unexpected cases for water treatment system, sludge treatment system, etc. There is a character that hates the external loading load input as much as possible. The reason is that it is difficult to accurately and long-term infer the effects of externally loaded substances as a whole plant. For example, the amount of inactive sludge increased due to the external organic matter added to the water treatment system as a biological carrier, the amount of hydrogen sulfide generation in the digester increased, and the amount of external added to increase the amount of anaerobic digestion gas recovered There are scale trouble and decrease in calorific value of dewatering cake in the latter stage caused by organic matter, increase in return phosphorus load and increase in the amount of used water treatment chemicals due to external organic matter added to improve dewaterability.

  That is, conventionally, although there is a fiber material utilization concept for one purpose, such as "gas generation amount" and "improvement of dewaterability", a person skilled in the art of actual plant design and plant maintenance and management needs a minimum. It is common sense that it should be limited to a single, unitary use of the material, and from the point of view that the influence becomes complicated and entails a large risk, the addition of the fiber material to multiple locations and its addition amount Efforts at actual plants for adjustment and their systematic integrated evaluation as a whole plant have not been made, and there is almost no literature on them.

  In view of the above problems, the present invention provides a method and an apparatus for treating organic wastewater or sludge capable of improving the treatment efficiency in the treatment process and the entire treatment system.

  In order to solve the above problems, the inventors of the present invention added biodegradable organic fiber materials to be introduced into the system in the treatment process of organic wastewater or sludge incorporating an anaerobic treatment process represented by methane fermentation treatment. The method and its effect on the whole process were discussed under various conditions. In particular, the inventors of the present invention place importance on the whole evaluation as a whole plant including anaerobic treatment and dehydration treatment of water treatment system and sludge treatment system instead of the single-device evaluation method by adding textiles as in the prior art. The above problem is that the process is evaluated by the cost-oriented overall evaluation method including various fiber material addition methods, including cases where effects are small on one side, and effects are reasonable on other evaluation axes. I found a method that can solve the problem.

  The method for treating organic wastewater or sludge according to the embodiment of the present invention completed on the basis of the above findings is, in one aspect, treating organic wastewater or sludge and treating microorganisms using microorganisms. Method for treating organic wastewater or sludge, wherein the biodegradation is performed on organic wastewater or sludge subjected to aerobic treatment using aerobic microorganisms, or on organic wastewater or sludge after aerobic treatment An anaerobic treatment using an anaerobic microorganism is performed on the sludge to which the biodegradable organic fiber material is added and the biodegradable organic fiber material is added, and the solid-liquid separation treatment is performed before and / or after the anaerobic treatment. And a process of treating organic wastewater or sludge further comprising adding biodegradable organic fiber material to at least one treatment of anaerobic treatment and solid-liquid separation treatment.

  In one embodiment, the method for treating organic wastewater or sludge according to the embodiment of the present invention is to anaerobically treat a part of sludge to which biodegradable organic fiber material is added without passing through anaerobic treatment. Bypass to the subsequent solid-liquid separation process of

  The method for treating organic wastewater or sludge according to the embodiment of the present invention is, in still another embodiment, the position and addition of the biodegradable organic fiber material according to the physical properties of the biodegradable organic fiber material. Adjust the rate.

  In still another embodiment of the method for treating organic wastewater or sludge according to the embodiment of the present invention, the biodegradable organic fiber material has a fibrous form with a specific gravity of 0.75 to 1.15 and a fiber length of 6 mm or less. Contains substance.

  The method for treating organic wastewater or sludge according to the embodiment of the present invention is, in still another embodiment, aerobic treatment and anaerobic treatment when biodegradable organic fiber material is added to organic wastewater or sludge. The test which imitated is performed, and the addition position and addition rate of biodegradable organic fiber material are adjusted based on the result of the test.

  An apparatus for treating organic wastewater or sludge according to an embodiment of the present invention is, in one aspect, aerobic treatment means for aerobically treating organic wastewater or sludge using aerobic microorganisms, and aerobic treatment means Or an additive means for adding biodegradable organic fiber material to organic wastewater or sludge after aerobic treatment by aerobic treatment means, and anaerobic for sludge to which biodegradable organic fiber material is added Anaerobic treatment means that perform anaerobic treatment, solid-liquid separation means that performs solid-liquid separation treatment in the first and / or second stage of anaerobic treatment, and biodegradation for at least one treatment of anaerobic treatment and solid-liquid separation treatment And a re-adding means for further adding the organic fiber-based fiber material.

  In one embodiment, the apparatus for treating organic waste water or sludge according to the embodiment of the present invention is a part of the sludge to which the biodegradable organic fiber material is added without being passed through the anaerobic treatment means. A detour line is provided for detouring to the solid-liquid separation means downstream of the processing means.

  In another embodiment, the apparatus for treating organic wastewater or sludge according to the embodiment of the present invention controls the rate of addition of biodegradable organic fiber material based on the physical properties of biodegradable organic fiber material. The apparatus further comprises control means.

  According to the present invention, it is possible to provide a method and apparatus for treating organic wastewater or sludge capable of improving the treatment efficiency in the treatment process and the entire treatment system.

It is a schematic diagram showing the processing system applicable to the processing method of the organic waste water or sludge concerning the embodiment of the present invention, and illustrates the addition position of the fiber substance added in consideration of the efficiency improvement of aerobic processing. FIG. It is a schematic diagram showing the processing system applicable to the processing method of the organic waste water concerning the embodiment of the present invention, or sludge, and illustrates the addition position of the textiles added in consideration of streamlining of anaerobic processing. FIG. It is a schematic diagram showing the processing system applicable to the processing method of the organic waste water concerning the embodiment of the present invention, or sludge, and an illustration of the addition position of the textiles added in consideration of efficiency improvement of solid-liquid separation processing. It is a figure to do. Characteristics according to the type A~C biodegradable organic fiber material (fiber material aerobic decomposition rate (AD3), fibrous materials anaerobic decomposition rate (DD7), fibrous materials derived from CH ₄ generation rate (FG7), 3 days It is a graph which illustrates the evaluation result of the amount of textiles (FI3) of sludge after an aeration test, and the amount of textiles (FO7) of sludge after a seven-day anaerobic vial test, respectively. It is a processing flow figure which shows the addition position of the textiles in Examples 1-3, respectively.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiment shown below exemplifies an apparatus and a method for embodying the technical idea of the present invention, and the technical idea of the present invention specifies the structure, arrangement and the like of the component parts as follows. Unless otherwise stated, "%" in the present specification shall mean% by mass.

  In addition, below, the standard activated sludge process is employ | adopted as a water-treatment system, and the general sewage treatment plant which respectively adopts an anaerobic digestion process and a dehydration process as a sludge treatment system is demonstrated as an example. However, those skilled in the art can apply or apply to any treatment process such as food waste water treatment incorporating anaerobic treatment as a facility for treating organic waste liquid or organic matter, human waste water waste treatment, garbage and organic waste material waste water treatment, etc. Of course, it is not limited to the illustrated sewage treatment.

In the treatment process using organic wastewater or sludge as the target fluid, the aerobic water treatment process mixes the treatment target fluid with sludge containing a large amount of aerobic microorganisms such as activated sludge and introduces it into an aeration tank etc. By the action, the organic component is mineralized to a form such as CO ₂ or H ₂ O. Activated sludge usually floats in the liquid of the aeration tank, and is finally separated into sludge separated by sedimentation in a final settling tank and the like and treated water separated by supernatant. However, depending on changes in conditions such as inflow water quality and microbial activity such as activated sludge, the solid-liquid separation between sludge and treated water may be deteriorated in the gravity settling method. Therefore, a system that stabilizes the solid-liquid separation performance by fixing the activated sludge to a fixed filter medium such as artificially synthesized plastic or polyethylene glycol, or a fluid carrier, instead of suspending it is 20 years or more ago. Many have been proposed.

  Since the fluid carrier is flowing relative to the fixed filter medium, new substrate components are encountered again because they are always moving even if the surrounding substrate components to be taken up by the microorganisms attached to the surface of the fluid carrier are consumed. Although there is a high probability, the fixed filter media may become thickened because the amount of surface-adhering microorganisms increases too much, and when the fluidity near the filter media is reduced, the substrate component around the microorganisms is lacking, and the necessary oxygen supply is not sufficient. There is a risk that it is sufficient to reduce the activity of the microorganism. These fixed filter media and fluid carriers are used when maintaining high concentration of microorganisms in the reactor or when holding a fixed amount of ammonia oxidizing bacteria, nitrifying bacteria, etc. which are anaerobic microorganisms having relatively low growth rate. There are many. However, since these microbe-supporting carriers generally flow in a reactor made of concrete or metal, they can not escape deterioration or breakage during long-term operation, and it is necessary to replenish several dozens of percent a year. It is often the case. Moreover, although the carrier outflow from the reactor is prevented by the screen etc., many problems due to the clogging of the screen etc. are also reported and there are many problems. Materials, size, shape, specific gravity, physical treatment method and chemical treatment method of surface, etc. are selected as design elements as a carrier, and durability, fluidity, substrate permeability, adhesion of microorganisms, and the like of the carrier are selected. It is common to design the peelability and the like.

  When considering the method of using the fiber material in the evaluation axis of "biological carrier characteristics", the present embodiment basically proposes a method of using the biodegradable organic fiber material transiently. Specific examples of the “biodegradable organic fiber material” include cellulose residue after harvesting agricultural products, process waste materials from processing plants that use animals and plants as raw materials, and their residues or crushing waste materials, surface treatment, It is possible to use one that has been subjected to a partial chemical treatment or the like to adjust the particle diameter, surface wettability, specific gravity and the like. The main reason for using these organic waste materials as "biological carriers" is that the cost of supply is low or valuable. If the place where such organic waste material is generated is sufficiently close to the treatment facility, and the transportation cost and the supply and demand amount are met, the cost merit is further increased.

  When activated sludge microorganisms etc. are attached to the surface of the fiber material which is these organic waste materials and water treatment is performed under aerobic environment, the organic waste materials are significantly SRT: under aerobic condition of about 3 to 6 days. It is necessary to select a waste material that is maintained as a biological carrier for a certain period without decomposition and additionally does not elute some harmful chemicals such as pesticides on the liquid side. When such an organic waste material is used for aerobic treatment, for example, an aeration test for 3 days is carried out, and the fiber material aerobic decomposition rate (hereinafter also referred to as "AD3") is measured to determine the addition method. In the case of a material with a very high rate of degradation of fiber material under aerobic conditions, reduce or eliminate the amount of fiber material input to the aerobic process, and introduce fiber to the process after the subsequent anaerobic treatment process In some cases it may be more effective to increase the amount of substance added.

Excess sludge mainly composed of microorganisms generated in aerobic treatment such as wastewater is introduced into anaerobic treatment such as methane fermentation together with primary settling sludge. In the anaerobic treatment, the input organic substance is decomposed through acid fermentation and methane fermentation in the reaction tank to generate CH ₄ gas, CO ₂ gas, H ₂ gas and the like. In anaerobic digestion treatment in general sewage treatment, about 45 to 60% of organic matter is gasified, and the remaining 40 to 55% still remains in the sludge as organic matter. The biodegradable organic fiber material added as a biological carrier to the aerobic treatment step in this embodiment has a difference in decomposition rate and CH ₄ gas generation rate in the methane fermentation tank depending on its type, but in methane fermentation When importance is given to increasing the amount of gas generation, it is preferable that the substance is difficult to be decomposed by aerobic treatment of SRT for about 3 to 6 days, but it is a substance that is decomposed to some extent by anaerobic treatment of SRT for about 20 to 40 days .

When considering how to use the fiber material to be added on the evaluation axis of "increase in flammable gas" in anaerobic treatment, it is desirable that the organic component of the fiber material to be added be decomposed and gasified as much as possible in the anaerobic treatment process. However, depending on the physical properties of the fiber substance to be added, anaerobic decomposition may not progress so much, and in particular, most of biodegradable organic fiber substances have already been decomposed in the aerobic treatment process, and further decomposition in the anaerobic treatment process is If this can not be expected, it may be desirable to further introduce the added fiber material directly to the anaerobic treatment step separately from the fiber material introduced to the aerobic treatment step. In addition, when there is a possibility that the fiber substance does not elute in aerobic environment but may cause process failure such as scale or corrosion due to the metal ion eluting in anaerobic environment, etc. It is desirable to limit the fiber material to be fed into the waste water, or introduce a part of the sludge after the aerobic treatment process to which the fiber material has been fed into the subsequent solid-liquid separation process without passing through the anaerobic treatment process. In some cases. In addition, separation into sludge containing a large amount of fiber material and sludge containing a small amount of fiber material may allow the efficiency of the entire process to be improved by introducing one into an anaerobic treatment step and the other into a solid-liquid separation step. A centrifugal separation method or a sieve classification method is effective as a method of separating sludge containing a large amount of fiber material and sludge containing a small amount of fiber material discharged from the aerobic treatment step. Microorganisms attached to the fibrous material often form relatively large particles and relatively dense aggregates compared to ordinary activated sludge microorganisms, and it is relatively easy to physically separate them. In order to determine the above-mentioned items to be studied, the fiber substance to be added is subjected to a vial test under anaerobic conditions in advance for 7 days, and the fiber substance anaerobic decomposition rate (hereinafter also referred to as "DD7") and fiber It is desirable to measure the substance-derived CH ₄ generation rate (hereinafter also referred to as “= FG7”).

  The sludge that has undergone the anaerobic treatment process is introduced into the solid-liquid separation process and subjected to concentration treatment, dehydration treatment, and the like. Dehydrated cake may be carried out as it is, or may be carried out as drying treatment or incineration treatment and carried out as incineration ash. Although the organic and inorganic components derived from the fiber material introduced into the sludge in the aerobic treatment process and the anaerobic treatment process both remain to some extent in the sludge flowing into the solid-liquid separation process, both of them are solid-liquid separation In many cases, the performance is improved, and in particular when the fiber property is maintained, the filtrate guide pipe is such that the fiber component guides the separated water out of the system through the gaps of the solid particles in the squeezing step etc. Often play an important role and are often effective. Generally, the dewaterability of sludge is correlated with the VTS of the sludge, and the lower the VTS, the better the dewaterability of the sludge. Inorganic fine particles produced in the anaerobic treatment step generally include magnesium ammonium phosphate, calcium phosphate, calcium carbonate, gypsum, iron hydroxide, iron phosphate, etc. As long as it is, dewatering property is said to be somewhat improved. A part of these inorganic fine particles may be generated as a generated inorganic substance derived from the fiber substance to be added, but if the amount of generation is too large, the scale in the piping in the plant, the cause of flue clogging at the time of incineration and clinker Care must be taken in the selection of the fiber material and the proper addition amount in consideration of the whole process.

  When considering how to use the fiber material to be added on the evaluation axis of “solid-liquid separation characteristics before and after anaerobic treatment”, as described above, the solid-liquid separation property is improved by the presence of the fiber material. As the amount of fibrous material in the sludge before introduction into the sludge increases, the concentration of the sludge increases and it becomes possible to increase the concentration of sludge introduced into the anaerobic treatment process as necessary. For example, when a fibrous material is added to the aerobic treatment step, the fibrous material having microorganisms attached to the surface is often discharged from the aerobic treatment step while the fiber content still maintains a certain level of strength. When concentrating sludge before the anaerobic treatment and feeding it into the digester, etc., it is relatively easy to concentrate, and in many cases it is possible to carry out coagulation concentration with no chemical injection or a very small amount of chemical injection. High concentration digestion processing is possible at low cost, and in addition, the digester can be made compact. Of course, the same effect can be obtained also when the fiber substance is directly added to the anaerobic treatment process input sludge. Similarly, in the solid-liquid separation step after the anaerobic treatment step, the solid-liquid separation property (dehydration ability) is enhanced as the amount of fiber material in the sludge increases, so the amount of fiber matter in sludge input to the solid-liquid separation step is important become. The larger the amount of fiber, the lower the flocculating agent addition rate at the time of solid-liquid separation, the lower the moisture content of the dewatered cake, and the lower the amount of dewatered cake discharged as waste discharged out of the system. Both costs and cake disposal costs are reduced. In order to quantitatively understand the “solid-liquid separation characteristics before and after anaerobic treatment” in consideration of these items to be studied, we previously showed in advance the amount of fibrous material remaining in the sludge before anaerobic treatment or sludge after anaerobic treatment. Solid content of sludge before and after anaerobic treatment process using the amount of fibrous material of sludge after 3 days aeration test (hereinafter also referred to as “FI3”) and the amount of fibrous material of sludge after 7 days of anaerobic vial test (hereinafter also referred to as “FO7”) It is desirable to evaluate the liquid separation performance.

As described above, the overall efficiency of the entire process is the most efficient after quantitatively grasping the “biological carrier characteristics”, “combustible gas increase”, and “solid-liquid separation characteristics before and after anaerobic treatment” by the fiber substance added to the sludge. In order to function in a well-balanced manner and to realize stabilization of processing performance and cost reduction, the above-mentioned AD3: fiber material aerobic degradation rate (%: percentage per input fiber VS) before process construction, DD7: fibrous material anaerobic degradation rate (%: percentage per charged fibers VS), FG7: Textile materials from CH ₄ generation rate (%: comparison percentage is 100% of the charged fibers CODCr1g per CH ₄ emissions 0.35NL ), FI3: fiber matter ratio of sludge after aeration test for 3 days (%: crude suspension percentage of at least 74 μm per sludge VSS), and FO7: fiber matter ratio of sludge after a 7 day anaerobic vial test (%: Measure the coarse floating matter percentage (74 μm or more per mud VSS), judge comprehensively based on the results, and optimize the addition position of the fiber material, the addition ratio, the sludge transfer route and the ratio etc. Is desirable.

  Since the present embodiment is a method in which a fiber component as an organic substance is introduced into a water treatment system or a sludge treatment system, a long-time aeration method, which is a type of activated sludge treatment method, is utilized by utilizing the treatment according to the present embodiment. Removal of phosphorus other than organic matter treatment, nitrogen removal, sludge volume reduction in modified methods such as OD method, anaerobic aerobic method, anaerobic anoxic aerobic method, step inflow method, membrane separation activated sludge, batch activated sludge method etc. It is also possible to optimize the fiber addition position and addition amount in consideration of evaluation items such as. Similarly, anaerobic treatment methods such as high concentration anaerobic digestion, carrier input anaerobic digestion, dry anaerobic digestion, etc., and dewatering treatment methods such as belt press type, centrifugal type, screw type, capillary type utilizing type etc. are considered. Of course, it is possible to optimize the addition position and the addition amount of the fibrous material.

  FIG. 1 is a schematic view showing a treatment system of a sewage treatment plant suitable for implementation of the method for treating organic wastewater or sludge according to the embodiment of the present invention. The present treatment system comprises the treatment equipment of the water treatment system 2 including the first settling basin 21 for treating organic wastewater or sludge 1, the activated sludge tank 22 and the final settling basin 23, and the first settling sludge 5 obtained in the first settling basin 21. And the mixing tank 31 which mixes the excess sludge 7 obtained in the final settling tank 23 and concentrates it as necessary to make the mixed raw sludge 8, and the digestion tank 33 and the digestion tank 33 which treats the mixed raw sludge 8 anaerobically It comprises the processing equipment of the sludge treatment system 3 provided with a solid-liquid separation device 36 for solid-liquid separation of the obtained digested sludge.

  In the first settling tank 21, organic wastewater or inflow 1 is separated into incipient sludge 5 containing a large amount of organic acid and outflow water 4 from organic wastewater or sludge 1. The effluent water 4 is subjected to aerobic treatment in the activated sludge tank 22 together with microorganisms including activated sludge which is an aerobic microorganism, whereby an activated sludge mixed liquid 6 is obtained. The activated sludge mixed solution 6 is subjected to solid-liquid separation in the final settling tank 23 to obtain excess sludge 7 and treated water.

  A part of the excess sludge 7 mainly composed of activated sludge microorganism which sediments and separates in the final settling tank 23 is returned to the activated sludge tank 22 and the other excess sludge 7 and the primary sludge 5 are mixed and mixed in the mixing tank 31 Raw sludge 8 is obtained. The mixed raw sludge 8 obtained in the mixing tank 31 is supplied to the digestion tank 33, and in the digestion tank 33, an anaerobic treatment using an anaerobic microorganism is performed. The digested sludge 11 is generated from the digestion tank 33 by the anaerobic digestion treatment, and solid-liquid separation treatment is performed, for example, in a solid-liquid separator 36 such as a dewatering device, to obtain a dehydrated cake and a concentrated liquid. The concentrate is first circulated to the sedimentation basin 21. The mixing tank 31 can have a concentration function, and the concentrated separated water obtained by the concentration processing in the mixing tank 31 is first returned to the settling tank 21.

  The method for treating organic wastewater or sludge according to the embodiment of the present invention is suitable for a treatment system for treating organic wastewater or sludge as shown in FIG. 1 and treating microorganisms using microorganisms. Used for Specifically, in the present treatment method, a biodegradable organic fiber material is added to organic wastewater or sludge subjected to aerobic treatment using aerobic microorganisms, or organic wastewater or sludge after aerobic treatment. The sludge to which the biodegradable organic fiber material has been added is subjected to an anaerobic treatment using an anaerobic microorganism, and the solid-liquid separation treatment is carried out in the former stage and / or the latter stage of the anaerobic treatment. The method further comprises adding a biodegradable organic fiber material to at least one treatment of the liquid separation treatment.

  A part of the sludge to which the biodegradable organic fiber material is added may be diverted to the solid-liquid separation treatment of the latter stage of the anaerobic treatment without passing through the anaerobic treatment. When, for example, calcium ion, sulfate ion, etc. are contained in the biodegradable organic fiber material, the sulfate ion becomes hydrogen sulfide by being fed to the anaerobic treatment, and the amount of chemicals used in the desulfurization treatment in the exhaust gas increases. Or, gypsum scale may be generated in the treatment tank to cause problems. When using such biodegradable organic fiber material, by bypassing a part of the sludge to the subsequent solid-liquid separation treatment, it is possible to reduce the trouble of the treatment system while reducing the number of biodegradable organic fiber materials. The solid-liquid separation characteristic by the addition can be improved.

  It is preferable that the addition position and the addition rate of the biodegradable organic fiber material be adjusted in accordance with the physical properties of the biodegradable organic fiber material. As described in detail below, the treatment efficiency of the entire treatment process can be improved by adjusting the amount (addition rate) and the addition position to be added according to the physical properties of the biodegradable organic fiber material.

  When adding biodegradable organic fiber material, aerobic treatment, anaerobic treatment in case of adding biodegradable organic fiber material to organic wastewater or sludge, and, if necessary, solid-liquid separation treatment is simulated. It is preferable to conduct the test and adjust the addition rate and the addition position of the biodegradable organic fiber material at each addition position based on the result of the test.

(Fiber substance addition to aerobic treatment)
As a suitable addition position for adding biodegradable organic fiber material to organic wastewater or sludge subjected to aerobic treatment using aerobic microorganisms, or organic wastewater or sludge after aerobic treatment, For example, it can be added from four places marked with stars shown in FIG. That is, (1) when added to the effluent water 4 overflowed from the first settling tank 21 (addition position 1 in FIG. 1), (2) when added to the activated sludge tank 22 (addition position 2 in FIG. 1) 3) When adding to the return sludge returned to the activated sludge tank 22 among the excess sludge 7 solid-liquid separated in the final settling tank 23 (addition position 3 in FIG. 1), (4) solid-liquid in the final settling tank 23 There are cases such as adding to the separated excess sludge 7 (addition position 4 in FIG. 1).

  In addition, when adding a biodegradable organic fiber material to the activated sludge tank 22 shown in the addition position 2 of FIG. 1, when an anaerobic aerobic method etc. are employ | adopted as a process in the activated sludge tank 22, it is necessary. Depending on whether it is an anaerobic tank or an aerobic tank, the biodegradable organic fiber material can be added.

(Addition to anaerobic treatment)
As a suitable addition position for adding a biodegradable organic fiber material to anaerobic treatment, for example, it can be added from six places marked with an asterisk shown in FIG. That is, (1) when added to organic wastewater or sludge 1 which is inflowing raw water (addition position 1 in FIG. 2), (2) sludge treatment after solid-liquid separation in final settling tank 23 and withdrawal of return sludge When it is added to the excess sludge 7 supplied to the treatment equipment of system 3 (addition position 2 in FIG. 2), (3) the excess sludge 7 solid-liquid separated in the final settling tank 23 and activated sludge as return sludge When added to excess sludge 7 including sludge returned to tank 22 (adding position 3 in FIG. 2), (4) added to mixing tank 31 (adding position 4 in FIG. 2), (5) mixing tank 31 (6) when added to the separated water obtained by the solid-liquid separator 36 (FIG. 2) There are addition positions 6) and the like.

  When the fiber material is added at the addition position 1 in FIG. 2, the added fiber material first settles in the settling tank 21, is mixed and optionally concentrated in the mixing tank 31, and is supplied to the digestion tank 33. Be done. When the fiber material is added at the addition position 2 of FIG. 2, the fiber material is supplied to the digester 33 via the mixing tank 31. When the fiber material is supplied at the addition position 3 in FIG. 2, a part of the fiber material is supplied to the digester 33 via the mixing tank 31 and the other part of the fiber material is the water treatment system 2 It is expected to improve the processing efficiency of aerobic processing by being returned to the When the fiber material is supplied to the separated water returned from the solid-liquid separator 36 at the addition position 6 in FIG. 2, a part of the fiber material passes through the first settling tank 21 and the mixing tank 31 and the digestion tank 33 As a result, the other part of the fiber material partially reacts with the components of the separated water while being supplied to the water treatment system 2, thereby reducing the load on the equipment of the water treatment system 2.

(Addition to solid-liquid separation process)
As a suitable position for adding a biodegradable organic fiber material to the solid-liquid separation treatment, for example, it can be added from seven places marked with an asterisk shown in FIG. That is, (1) when added to the digested sludge 11 charged to the solid-liquid separator 36 (addition position 1 in FIG. 3), (2) when directly added to the solid-liquid separator 36 such as a dehydrator (FIG. 3) 2), (3) To the bypass line 37 for diverting the mixed raw sludge 8 obtained in the mixing tank 31 to the solid-liquid separation process of the latter stage of the anaerobic treatment without passing through the digestion tank 33 for anaerobic treatment. In the case of addition (addition position 3 in FIG. 3), (4) in the case of addition to the mixed raw sludge 8 or concentrated sludge concentrated in the mixing tank 31 (addition position 4 in FIG. 3), (5) mixing tank 31 or when added to the concentration mechanism provided in the mixing tank 31 (addition position 5 in FIG. 3), (6) when added to excess sludge 7 withdrawn from the final settling tank 23 (addition position 6 in FIG. 3) 7) When adding to organic wastewater or sludge 1 which is influent raw water (addition of Fig. 3 Location 7), and the like.

  When the fiber material is added at the addition positions 4 and 5 in FIG. 3, it is preferable to take into consideration the amount of change in the fiber material contributed in the solid-liquid separation step according to the decomposition rate of the fiber material in the digestion tank 33. When the fiber material is added at the addition position 6 in FIG. 3, in consideration of returning a part of the excess sludge 7 as return sludge to the activated sludge tank 22 and decomposing the remaining sludge in the digestion tank 33 It is preferable to put it. When the fiber material is added at the addition position 7 in FIG. 3, the added fiber material first settles in the settling tank 21, is mixed in the mixing tank 31 and concentrated if necessary, and is supplied to the digestion tank 33. It is preferable to take into account what is done.

  The addition methods that take into consideration the “biological carrier characteristics” in these aerobic treatments, “increasing combustible gas” in anaerobic treatments, and “solid-liquid separation characteristics” in solid-liquid separation treatments are the installation area, layout, and the like of each treatment facility. Considering the water treatment control system, control panel capacity, fiber material import route, fiber material addition control system, flow lines for maintenance work and equipment and maintenance costs taking into account all of them, etc. It is desirable to determine the optimum addition position of

  In particular, when the present embodiment is adopted as remodeling work of an existing plant, the selection of the addition position of the fiber material is an important point, and depending on the type of the fiber material and the condition of the plant, FIGS. The addition position illustrated to 3 can be combined suitably. Further, as can be understood from the addition positions illustrated in FIGS. 1 to 3, 2 of the three effects of “biological carrier property”, “combustible gas increase” and “solid-liquid separation property” at 1 addition position. Although there are addition positions where one or more effects can be expected simultaneously, judgment is made based on test data on five evaluation items (AD3, DD7, FG7, FI3, FO7) exemplified below, according to the physical properties of the fiber material. It is desirable to do.

(Biodegradable organic fiber material)
The biodegradable organic fiber material has a specific gravity of 0.75 to 1.15, further 0.96 to 1.05, a fiber length of 6.0 mm or less, and further a fiber having a water length of 5.0 mm or less 15% The above fiber materials are suitably used. Specifically, cellulose fiber material (fiber material A) obtained by pulverizing and processing agricultural waste, fruit fiber material obtained by crushing food processing waste (fiber material B), improvement of wood processing system It is possible to use cellulose obtained by partially chemically treating waste, lignin-based fibrous material (fibrous C), and the like.

  The fibrous material A is a fibrous material having a moisture content of 15 to 45% and a fiber length of 50 μm to 5.0 mm, more typically 75 μm to 3.0 mm. This fibrous material has a specific gravity of 0.75 to 1.00 and a specific gravity of 0.85 to 0.95. In the water treatment process in which the fibrous material is charged, floating scum may occur if the specific gravity is too small, and conversely, it may precipitate in the reaction tank if the specific gravity is too large, and all adhere to the fiber content There is a risk of reducing the reactivity of the microorganism. The specific gravity described here is the air-dried specific gravity at a water content of 15%.

  The fibrous material B is a fibrous material having a moisture content of 50 to 85% and a fiber length of 30 μm to 4.0 mm, more typically 150 μm to 3.0 mm. This fibrous material has a specific gravity of 0.85 to 1.10, and more typically, a specific gravity of 0.95 to 1.05. The specific gravity described here indicates the air-dried specific gravity at a water content of 50%.

  The fibrous material C has a moisture content of 40 to 97% and various forms such as a solid or liquid, and the fiber length is 30 μm to 6.0 mm, more typically 40 μm to 4.0 mm, and the specific gravity is 0 Containing fibrous materials of 75 to 0.95, more typically 0.75 to 0.90; The specific gravity described here is the air-dried specific gravity at a water content of 15%.

The above-mentioned AD3 (Fibrous material aerobic decomposition rate (%: percentage per input fiber VS) above, DD7 (Fibrous material anaerobic decomposition rate (%) for three types of fibrous materials A, B, C having different sources) : percentage per charged fibers VS)), FG7 (fiber material from CH ₄ generation rate (%: comparison percentage is 100% to CH ₄ emissions 0.35NL per charged fibers CODCr1g)), FI3 (3 days aeration test Fiber matter ratio of post sludge (%: 74 μm or more coarse floe percentage per sludge VSS), and FO7 (7 day fiber matter ratio of sludge after anaerobic vial test (%: 74 μm coarse floe percentage per sludge VSS) An example of measuring) is shown in FIG.

As shown in FIG. 4, in the case of the textile A, although the decomposition rate is low at 13% in aerobic treatment AD3, the decomposition rate is high at 72% in DD7 anaerobic treatment, and the CH ₄ conversion ratio FG7 in anaerobic treatment is also It is relatively high at 64%. Also, the fiber rate FI3 after aerobic treatment is relatively high at 18%, and solid-liquid separation and concentration seems to be relatively good, and it can be inferred that low drug concentration and high concentration digestion are possible. The fiber content FO7 after anaerobic digestion is relatively low at 10%, and the solid-liquid separation performance is estimated to be relatively poor.

  When the process of the whole plant is designed in view of the result of the evaluation item of the textile A shown in FIG. 4, the addition rate of the textile A to the sludge MLSS in the aerobic treatment step is 3 to 30%, more preferably 8 to 8 It is preferable to charge at an addition rate of 22%. For example, the sludge introduced into the anaerobic treatment step is mechanically concentrated without chemical injection, or 2.0 to 4.5 times the coagulant content relative to 0.20% or less of the coagulant per sludge SS, more preferably Is concentrated so that it becomes 2.5 to 3.5 times, and assuming that it is carried out about 30 days, there is not much fiber remaining in the sludge after the anaerobic digestion process, so it is put into the anaerobic treatment process The solid matter separation is enhanced by re-adding the fiber material A at an addition rate of 3 to 20%, more preferably 5 to 15%, to the sludge SS to solid / liquid separation treatment (dehydration treatment).

The merits obtained by the above processing method are that the required capacity of the digester can be reduced by low cost high concentration digestion, increase of CH ₄ surplus gas recovery amount in digester, reduction of dosage rate in dehydration, dehydration There is a reduction in the amount of chargeable waste cake generated after processing.

In the case of the fibrous material B, the decomposition rate is high at 58% in the aerobic treatment AD3 and is very high at 83% on the anaerobic treatment DD7. The CH ₄ conversion rate FG7 in anaerobic treatment is also relatively high at 69%. On the other hand, FI3 indicating the percentage of fibrous material after aerobic treatment is relatively low at 11%, and as a result, the added fibrous material is almost decomposed, and the amount remaining after aerobic treatment is small I understand. Therefore, in the case of the fiber material B, the solid-liquid separation-concentration property to sludge subjected to aerobic treatment is considered to be relatively poor, and it can be inferred that low concentration injection and high concentration digestion are difficult as it is. The FO7 indicating the fiber content after anaerobic digestion is also relatively low at 7%, and it is presumed that the solid-liquid separation performance of digested sludge is also relatively poor if this is left as it is.

  When the process of the whole plant is designed in consideration of the result of the evaluation item of the textile material B, the textile material B is not introduced into the aerobic treatment process in large quantities in the nominal as a biological carrier in the aerobic treatment process. Accordingly, the system is appropriately added as a hydrogen donor for denitrification of water treatment system, or added to excess sludge 7 obtained from final settling tank 23 after aerobic treatment, and the addition rate at that time is 2 to 12% per sludge MLSS is preferred. Furthermore, with respect to the sludge immediately before introducing the fiber material B into the anaerobic treatment process after aerobic treatment, the addition rate is 6 to 30% per sludge MLSS, more preferably 10 to 20%, and concentration treatment Into the anaerobic digestion process without Since the fiber content is almost decomposed and hardly remains in the sludge after the 30-day anaerobic digestion process, the addition rate of 3 to 15% per sludge SS, more preferably 5 to 10% just before solid-liquid separation The fiber material B is re-added to enhance solid-liquid separation and dewatered.

The merits obtained by the above-mentioned processing method include an increase in the amount of CH ₄ surplus gas recovered in the digestion tank, a reduction in chemical injection rate in dehydration processing, and a reduction in the generation amount of tolled waste cake after dehydration processing.

In the case of the fibrous material C, the decomposition rate is low at 7% in the aerobic treatment AD 7 and at 24% in the anaerobic treatment DD 7 and is relatively low at 28% in the CH ₄ conversion rate FG 7 in the anaerobic treatment. It can be seen that the fiber content FI3 after aerobic treatment is relatively high at 20%, and most of the added fibers remain. Therefore, solid-liquid separation and concentration for sludge subjected to aerobic treatment is considered to be relatively good, and it can be inferred that low chemical concentration and high concentration digestion are easy. The fiber content FO7 after anaerobic digestion is relatively high at 17%, and it is speculated that the solid-liquid separation performance of the digested sludge is also relatively good.

When the process of the whole plant is designed in consideration of the result of the evaluation item of the fiber C, the addition ratio of 2 to 18% of the fiber C per sludge MLSS, more preferably 5 to 12% in the aerobic treatment step. The sludge to be introduced into the activated sludge at a fixed rate and introduced into the anaerobic treatment process is 1.5 to 4.5 times after the chemical rate of less than 0.15% of the chemical injection rate or 0.15% or less of flocculant per sludge SS Preferably, mechanical concentration of 2.5 to 3.5 times is efficiently good. However, since it is unlikely to increase the amount of excess CH ₄ gas recovered from the added fiber material, it is considered unnecessary to introduce it into the aerobic treatment step or the anaerobic digestion step more than necessary.

  Moreover, since the fiber material C contains a relatively large amount of calcium ions and sulfate ions, relatively many calcium phosphate particles in which phosphate ions and calcium ions are combined are generated in the aerobic treatment step, which contributes to phosphorus removal in the water treatment system can do. On the other hand, in the anaerobic digestion process, the sulfate ion considered to be derived from fiber material C becomes hydrogen sulfide, and some problems may be seen due to the increase in the amount of chemicals used in desulfurization treatment in exhaust gas and the generation of gypsum scale. It is necessary to adjust the amount of C introduced into the aerobic treatment step and the anaerobic digestion step within the range where the disadvantages are unlikely to occur. A large amount of fiber remains in the sludge after the 30-day anaerobic digestion process, and even with this sludge, the moisture content of the cake is relatively low, but it is further 1 to 12% per sludge SS, more preferably 3 to 3 It is possible to further improve the dewatering ability by re-introducing the fiber material C at an addition rate of 8%.

Among the advantages obtained by the above treatment method are the reduction in the amount of chemicals used to remove phosphorus by the phosphorus removal effect in water treatment systems, the reduction in digester volume required by low cost high concentration digestion treatment, CH _{4 in the} digester Examples of the method include an increase in the amount of surplus gas recovered, a reduction in the rate of chemical injection in dehydration processing, and a reduction in the amount of tolled cake generated after dehydration processing.

(Processing device)
The treatment apparatus according to the embodiment of the present invention comprises an aerobic treatment means for performing an aerobic treatment using an aerobic microorganism on organic wastewater or sludge, an organic wastewater or sludge, or an organic after aerobic treatment. Additive means for adding biodegradable organic fiber material to anaerobic wastewater or sludge, anaerobic treatment means for performing anaerobic treatment on sludge to which biodegradable organic fiber material is added, anaerobic treatment Solid-liquid separation means for performing solid-liquid separation treatment in the first stage and / or second stage of the treatment, and re-addition means for further adding biodegradable organic fiber material to at least one treatment of anaerobic treatment and solid-liquid separation treatment Equipped with

  As the aerobic treatment means, for example, an activated sludge tank 22 shown in FIGS. 1 to 3 for treating wastewater or sludge using an aerobic microorganism such as activated sludge is suitably used. The addition means may be any known means as long as it is an apparatus capable of adding biodegradable organic fiber material at a predetermined addition rate. The anaerobic treatment means is a treatment device for performing an anaerobic treatment using an anaerobic microorganism to generate biogas such as methane gas. For example, the digestion tank 33 of FIGS. 1 to 3 can be used. At the front stage of the anaerobic treatment apparatus, solid-liquid separation means such as a concentrator for concentrating sludge can be provided. The solid-liquid separator 36 shown in FIGS. 1 to 3 such as a dewatering device for dewatering the digested sludge 11 generated by the anaerobic treatment can be provided downstream of the anaerobic treatment device.

  As shown in FIG. 3, a part of the sludge to which the biodegradable organic fiber material is added is transferred to the solid-liquid separator 36 at the latter stage of the digestion tank 33 without passing through the digestion tank 33 which is an anaerobic treatment means. And a bypass line 37 may be provided. In addition, as described above, the biodegradable organic fiber material obtained by the test is conducted by carrying out a test simulating aerobic treatment, anaerobic treatment and solid-liquid separation treatment to the added biodegradable organic fiber material. Control means (not shown) may be further provided to adjust the addition rate of the biodegradable organic fiber material at each addition position based on the physical properties of the substance.

  Examples of the present invention are given below together with comparative examples, but these examples are provided to better understand the present invention and its advantages, and are not intended to limit the invention.

  The treatments of Examples 1 to 3 were performed based on the treatment flow shown in FIG. 5 as a pilot test using raw water flowing into the F sewage treatment plant. (1) of FIG. 5 shows the addition position of the fiber material in Example 1, (2) shows the addition position of the fiber material in Example 2, and (3) shows the addition position in Example 3.

  The water treatment system was operated under the activated sludge treatment method adopting anaerobic anaerobic method. The operating conditions related to the evaluation items are HRT: 10 hours for activated sludge treatment and SRT: 72 hours for water treatment system, and mixed sludge of primary sludge and excess sludge is put into the digester in the sludge treatment system. Digestion conditions: medium temperature digestion at 35 ° C, digestion tank hydraulic retention days: 25 days, adopts a belt press type dewatering machine for sludge treatment, and dewatering after dewatering by polymer flocculant 1 liquid treatment of unit price 500 yen / kg, dewatering The cake was transported out of the room at 15,000 yen / t, and the power unit price was evaluated as 15 yen / kwh.

Regarding the addition rate and addition position of the fiber substance to be added in Examples 1 to 3, the addition rate and addition position are respectively appropriate based on the physical property data on the above five evaluation items (AD3, DD7, FG7, FI3 and FO7) The operation was performed with the value set. The evaluation items of the processes in Examples 1 to 3 are all expressed as a comparison percentage to the performance figures per influent sewage treatment amount to be treated in Comparative Example 1, and the items “Plant power cost” “Used chemical cost” “Plant installation The five items were “Area”, “Excess CH ₄ gas recovery amount” and “Cake disposal cost”. The results are shown in Table 1.

  In Example 1, the fibrous material A is added at an addition rate of 15% per sludge MLSS in the aerobic treatment process, and 0.1% of polymer flocculation per sludge SS is added to the sludge introduced into the anaerobic treatment process. After the addition of the agent, the sludge concentration is concentrated 2.5 times using a screen type mechanical concentrator, and the concentrated sludge is introduced into the anaerobic digestion process for 25 days of retention days, and sludge SS is applied to the sludge after anaerobic digestion. Method to obtain dewatered cake by re-adding the fiber A to sludge with an addition rate of 8% per unit and introducing it into solid-liquid separation (dehydration process) and adding polymer flocculant 1.2% per sludge SS It was adopted.

  As a result, the plant power cost could be reduced by 12 pt%. This is because the sludge introduced into the digestion tank is concentrated 2.5 times, and the volume of the digestion tank is reduced to 2/5 of Comparative Example 1. Accordingly, the power of ancillary equipment such as a stirrer, pump and heating equipment is small. Is the main factor. The chemicals used were newly used as flocculants for sludge concentration, but as dewatering flocculants, they could be dewatered at a relatively low injection rate and reduced by 13 pt% as a whole. The plant installation area was reduced by 15 pt% as a whole since the digester capacity was 2/5 of Comparative Example 1.

The amount of CH ₄ surplus gas recovered in the digester was the addition of the evolved gas from fiber A that was newly added as organic matter, and the digester capacity was 2/5, so the recovery for digestion tank heating was As CH ₄ combustion heat energy requirement decreased significantly, the amount of CH ₄ surplus gas sent to power generation increased by 36 pt%. The cost of disposing of the cake decreased by 13pt%. This is because the sludge was changed to a highly dewaterable sludge containing a large amount of fibers, and the moisture content of the cake decreased to about 75%, which was 7 pt% lower than the moisture content of 82% of Comparative Example 1 As for the amount, the effect which was more than offsetting the increase in solids due to the added fiber A was obtained.

  In Example 2, the fiber B is not usually introduced into the aerobic treatment step, and only the necessary amount of the fiber B is anaerobic only when the hydrogen donor is insufficient in the denitrification reaction in the anaerobic tank in the anaerobic aerobic method. In the line just before the tank, 2 to 5% (average 3%) was added. Fiber B is added to the sludge introduced into the anaerobic treatment process at an addition rate of 23% per sludge SS, introduced into the anaerobic digestion process with a retention period of 25 days, and the sludge after the anaerobic digestion In contrast to this, a method is used to obtain a dewatered cake by re-adding the fiber material B to the sludge at an addition rate of 5% per sludge SS and introducing it into the dewatering step and adding a polymer flocculant 1.4% per sludge SS. did.

As a result, although the plant power cost and the plant installation area increased by 2 to 3% each due to the increase in the number of equipments, the chemicals used can be dewatered at a relatively low dosage rate for dewatering coagulant. The overall reduction was 9 pt%. CH ₄ excess gas recovery amount results CH ₄ excess amount of gas generated CH ₄ gas was increased significantly from the fibers thereof B since freshly poured fibers Compound B were readily degradable as organic matter in digester It increased by 43 pt%. The cost of disposing of the cake decreased by 9pt%. This is because the sludge changed to a highly dewaterable sludge containing a large amount of fiber, and the moisture content of the cake decreased to about 77%, which was 5 pt% lower than the moisture content of the cake of 82% of Comparative Example 1, As an amount, an effect which is more than offsetting the increase in solids due to the added fiber B was obtained.

  In Example 3, the fiber material C is added at an addition rate of 11% per sludge MLSS in the aerobic treatment step, and a screen type mechanical concentrator is used without sludge to the sludge introduced in the anaerobic treatment step. Sludge concentration is concentrated 2.5 times, and the concentrated sludge is introduced into the anaerobic digestion process with 25 days of retention days, and the sludge after the anaerobic digestion has an addition rate of 6% per sludge SS to the fibrous material C Was added to the sludge, introduced into the dewatering process, and a method of obtaining a dewatered cake by adding a polymer flocculant 1.1% per sludge SS was adopted.

As a result, the plant power cost has been reduced by 13 pt%. This is because the sludge introduced into the digestion tank is concentrated 2.5 times, and the volume of the digestion tank is reduced to 2/5 of Comparative Example 1. Accordingly, the power of ancillary equipment such as a stirrer, pump and heating equipment is small. Is the main factor. The amount of chemicals used was reduced by 17 pts on the whole, as good dewatering was possible at a relatively low dosage rate as a flocculating agent for dehydration. The plant installation area was reduced by 15 pt% as a whole since the digester capacity was 2/5 of Comparative Example 1. The amount of CH ₄ surplus gas recovered in the digester was slightly increased as the volume of the digester tank was 2/5, in addition to a slight addition of the evolved gas derived from fiber material C, which was newly added as an organic substance. The amount of CH ₄ surplus gas sent to power generation was increased by 22 pt% as the recovered CH ₄ combustion thermal energy requirement decreased significantly. Cake disposal costs were reduced by 25 pt%. This is because the sludge changed to a highly dewaterable sludge containing a large amount of fibers, and the moisture content of the cake decreased to about 69%, which was 13 pt% lower than the moisture content of the cake of 82% of Comparative Example 1, As an amount, an effect more than offsetting the increase in solids due to the added fiber C was obtained.

1 organic waste water or sludge 2 water treatment system 3 sludge treatment system 4 runoff water 5 primary sedimentation sludge 6 activated sludge mixed liquid 7 surplus sludge 8 mixed raw sludge 11 digested sludge 21 first settling tank 22 ... activated sludge tank 23 ... final settling tank 31 ... mixing tank 33 ... digestion tank 36 ... solid-liquid separation device 37 ... bypass line

Claims (6)

A method for treating organic wastewater or sludge, which targets organic wastewater or sludge and treats organic components using microorganisms.
A biodegradable organic fiber material is added to organic wastewater or sludge before or during aerobic treatment using aerobic microorganisms, or to sludge obtained by the aerobic treatment. ,
Performing anaerobic treatment using anaerobic microorganisms on the sludge to which the biodegradable organic fiber material is added;
Solid-liquid separation treatment before and / or after the anaerobic treatment,
Further adding the biodegradable organic fiber material to at least one of the anaerobic treatment and the solid-liquid separation treatment ;
The biodegradability is based on the evaluation results of the decomposition rate in the aerobic treatment and the anaerobic treatment of the biodegradable organic fiber material, the increase in the amount of combustible gas, and the fiber ratio after the aerobic treatment and the anaerobic treatment. What is claimed is: 1. A method of treating organic wastewater or sludge comprising adjusting the position and rate of addition of an organic fiber material .   2. The method according to claim 1, wherein a part of the sludge to which the biodegradable organic fiber material is added is diverted to a solid-liquid separation process subsequent to the anaerobic treatment without passing through the anaerobic treatment. Method of treating organic wastewater or sludge as described.   The method for treating organic wastewater or sludge according to claim 1 or 2, wherein the biodegradable organic fiber material comprises a fibrous material having a specific gravity of 0.75 to 1.15 and a fiber length of 6 mm or less. . Claims, characterized in that to obtain the evaluation result by the aerobic treatment and the anaerobic row Ukoto test that simulates the process in case of adding the biodegradable organic fiber material to said organic waste water or sludge organic waste water or treatment method of sludge according to any one of 1 to 3. Aerobic treatment means for aerobic treatment of organic wastewater or sludge using aerobic microorganisms;
And adding means for adding the biodegradable organic fiber material relative to the organic waste water or sludge during aerobic treatment before or aerobic treatment, sludge is stomach obtained by prior Symbol aerobic treatment,
Anaerobic treatment means for anaerobically treating the sludge to which the biodegradable organic fiber material is added;
Solid-liquid separation means for performing solid-liquid separation treatment at a stage before and / or after the anaerobic treatment;
Re-adding means for further adding the biodegradable organic fiber material to at least one of the anaerobic treatment and the solid-liquid separation treatment ;
The biodegradability is based on the evaluation results of the decomposition rate in the aerobic treatment and the anaerobic treatment of the biodegradable organic fiber material, the increase in the amount of combustible gas, and the fiber ratio after the aerobic treatment and the anaerobic treatment. An apparatus for treating organic waste water or sludge characterized by adjusting the addition position and the addition rate of the organic fiber material . A detour line is provided for diverting a part of the sludge to which the biodegradable organic fiber material is added to the solid-liquid separation means downstream of the anaerobic treatment means without passing through the anaerobic treatment means. The apparatus for treating organic wastewater or sludge according to claim 5 .