JP2008246326A - Deodorizing method and deodorizer for organic sludge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a deodorizing method which enables the generation of odors from organic sludge to be inhibited regardless of the water content of the organic sludge, and to provide a deodorizer for organic sludge which can be used for the deodorizing method. <P>SOLUTION: The deodorizing method comprises the first process for mixing the organic sludge with a volatile fatty acid decomposing mold, and the second process for culturing the mold mixed with the organic sludge in the first process. The deodorizer contains the volatile fatty acid decomposing mold. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for deodorizing organic sludge, and a deodorizer for organic sludge. Moreover, it is related with the solid fuel containing the sludge obtained by the said deodorizing method.

  In sewage treatment, human waste treatment, organic wastewater treatment generated from food factories and paper pulp factories, and livestock waste treatment such as livestock manure, sludge is generated along with the treatment. Sludge is usually discharged as slurry sludge from the water treatment step of each treatment, and then the water is removed through various steps to reduce the volume. Taking sewage treatment as an example, slurry sludge becomes cake-like dewatered sludge by concentration treatment and dewatering treatment. The dehydrated sludge becomes dry sludge when further dried, and becomes incinerated ash when incinerated. Dehydrated sludge and dried sludge are disposed of in landfills, used as fertilizers and compost, or used as cement resources. Incinerated ash is disposed of in landfills or used as various building material materials.

  In recent years, the use value of organic sludge as biomass has been attracting attention against the background of social needs to reduce carbon dioxide emissions. Based on the carbon neutral nature of biomass, the value of dry sludge as a fuel is particularly noted. Sewage sludge is actually being used as a substitute for fossil fuels.

  Dehydrated sludge and dried sludge are derived from organic components in sludge and generate various odors. Therefore, when handling dewatered sludge and dried sludge, it is required to reduce odor generated from the sludge. In particular, dry sludge is strongly required to develop deodorization technology because of its new widespread use.

  Examples of odorous substances generated from dehydrated sludge and dried sludge include organic acids such as valeric acid, butyric acid and propionic acid; nitrogen compounds such as ammonia and amines; sulfur compounds such as hydrogen sulfide, methyl mercaptan and methyl sulfide. Can be mentioned. Further, examples of the odor substance generated from the dried sludge include aldehydes such as acetaldehyde newly generated by the sludge drying treatment.

  Conventionally, various studies have been made on deodorizing agents for dewatered sludge and deodorizing methods for dewatered sludge. Since dehydrated sludge has a high water content, various deodorization methods can be applied relatively easily. On the other hand, the deodorant for dry sludge and the deodorization method of dry sludge are overwhelmingly less studied than dehydrated sludge.

  For example, a deodorizing method using an oxidizing agent such as hydrogen peroxide, alkali persulfate, chlorite, and hypochlorite is known. Although the method using these oxidizing agents can be applied to dehydrated sludge, the deodorizing effect is lost in a short time. In the method of adding a chemical such as an oxidizer to deodorize, in many cases, a chemical dissolved in a solvent such as water is added to dehydrated sludge or sludge before dehydration. When added as a solution, the moisture content of the dried sludge increases and the properties of the dried sludge change, which may affect the use of the dried sludge. Further, when dry sludge is manufactured by evaporating and removing moisture from the sludge by heating, it can be said that adding water to add chemicals to the sludge is inefficient in the first place. For this reason, a method for adding a deodorizing agent as a solution to dry sludge has not been studied. In addition, when adding an oxidizing agent to dry sludge, there also exists a problem that the odor generation amount of aldehydes increases depending on the kind of oxidizing agent.

A method using microorganisms is also known as a deodorizing method for dewatered sludge. In Patent Document 1, when performing aerobic fermentation of dehydrated sludge, powder shells and crushed waste paper are added to the dehydrated sludge, aerobic microorganisms such as filamentous fungi and actinomycetes are propagated on the waste paper fibers, A method of decomposing and absorbing malodor is disclosed. Patent Document 2 discloses a method in which sludge is fermented without causing malodor by spraying fermented bacteria mainly composed of lactobacilli and yeast after mixing dehydrated sludge and wood chips. However, the methods disclosed in Patent Documents 1 and 2 are intended for dewatered sludge, and it is difficult to apply these disclosed methods as they are to the dried sludge. This is because dehydrated sludge has a high moisture content, so that the activity of microorganisms becomes active and odors can be removed by microorganisms. However, the dry sludge has a low moisture content, so that the activity of microorganisms is generally not sufficient. Furthermore, dry sludge also generates odors of volatile aldehydes that are not found in dehydrated sludge. From this point of view, it is difficult to apply the deodorized sludge deodorization method as it is.
JP 2001-302377 A JP 2000-169270 A

  This invention is made | formed in view of the said situation, The objective is to provide the deodorizing method which can suppress generation | occurrence | production of the odor from organic sludge irrespective of the moisture content of organic sludge. Moreover, it is providing the deodorizing agent for organic sludge which can be used for the said deodorizing method. Furthermore, it is providing the solid fuel containing the sludge obtained by the said deodorizing method.

  In order to solve the above problems, the present inventors have examined a deodorization method capable of suppressing odor from organic sludge regardless of the moisture content of organic sludge. As a result, volatile fatty acid-degradable filamentous fungi are like dried sludge. The present invention was completed by finding that it exhibits an excellent deodorizing effect even in an environment with a low moisture content.

  That is, the deodorizing method of the present invention includes the first step: a step of blending organic sludge and volatile fatty acid-degradable filamentous fungi, the second step: the filamentous fungus blended with organic sludge in the first step. It is characterized in that it has a step of culturing. According to the said structure, deodorization of organic sludge is attained irrespective of the moisture content of organic sludge, and especially generation | occurrence | production of the odor of aldehydes peculiar to organic acid and dry sludge can be suppressed.

  In the deodorizing method of the present invention, it is preferable to use microascus silosus as the volatile fatty acid-degrading filamentous fungus. Microascus tyrosus is preferably used because it can effectively suppress the generation of odors of organic acids and aldehydes.

  In the deodorizing method of the present invention, the pH of the organic sludge is preferably in the range of 5 to 10, and the water content of the organic sludge is preferably 15% by mass to 90% by mass. In the second step, the culture is preferably performed in the range of 15 ° C to 45 ° C. Under the above conditions, the activity of the filamentous fungus can be increased, and an excellent deodorizing effect can be obtained.

  In the second step of the deodorizing method of the present invention, the culture period is preferably 1 day or longer. By setting the culture period to 1 day or longer, an excellent deodorizing effect can be obtained.

  In the deodorizing method of the present invention, it is also a preferred embodiment to have a step of heating the sludge obtained in the second step as the third step. Further, by adding a step of heating the sludge, the odor of the obtained sludge is further reduced, and the moisture content of the sludge is reduced, so that the application range of the sludge is expanded.

  Since the odor of the deodorized sludge obtained by the deodorizing method of the present invention is greatly reduced, the handleability and work environment of the sludge are improved. In addition, in the deodorizing method of the present invention, since the amount of volatile fatty acid-degradable filamentous fungi used as a deodorizing agent is small, the moisture content of the deodorized sludge is hardly increased by the deodorizing treatment, and the sludge heat generation is reduced. There is no significant increase in the amount of inorganic components or significant decrease in the amount of organic components, and there is no increase in the content of halogen elements such as chlorine, which causes equipment corrosion during combustion. Therefore, the deodorized sludge obtained by the deodorizing method of the present invention can be particularly suitably used as a solid fuel.

  The deodorizer of the present invention is characterized by containing volatile fatty acid-degradable filamentous fungi. In addition, the volatile fatty acid-degrading filamentous fungus is particularly preferably Microascus tyrosus. According to the said structure, deodorization of organic sludge is attained irrespective of the moisture content of organic sludge, and especially generation | occurrence | production of the odor of aldehydes peculiar to organic acid and dry sludge can be suppressed.

  The deodorizing method and the deodorizing agent of the present invention can suppress the generation of odor from organic sludge, particularly the generation of odor of aldehydes peculiar to organic acids and dry sludge, regardless of the moisture content of the organic sludge. The deodorized sludge obtained by the deodorizing method of the present invention can be particularly suitably used as a high-quality solid fuel with little odor.

  First, the deodorizer of this invention is demonstrated. The deodorizer of the present invention is characterized by containing volatile fatty acid-degradable filamentous fungi.

  Examples of the volatile fatty acid that can be decomposed by the filamentous fungus contained in the deodorizer of the present invention include propionic acid, n-butyric acid, n-valeric acid, i-valeric acid, and the like, and the filamentous fungus is at least selected from these. It is preferable that one type can be decomposed. The filamentous fungus contained in the deodorizer of the present invention can further decompose at least one aldehyde selected from acetaldehyde, propionaldehyde, n-butyraldehyde, i-butyraldehyde, n-valeraldehyde, and i-valeraldehyde. Is preferred.

  Examples of the filamentous fungi contained in the deodorizer of the present invention include the genus Microascus, the genus Pseudallescheria, the genus Scopulariopsis, the genus Petriella and the like. These may contain only one type or two or more types. As the filamentous fungus contained in the deodorizer of the present invention, more specifically, for example, Microascus cirrosus, Pseudallescheria boydii, Scopulariopsis brevicaulis, Petriella setifera and the like are shown, and these may include only one type or two or more types. As the microascus tyrosus, particularly, the DC2b strain that has been demonstrated to exhibit an excellent deodorizing effect even in a low water content environment can be suitably used.

  When the present inventors verified the homology by amplifying a portion containing a gene encoding an eukaryotic 18S ribosomal RNA by PCR, microascus silosus and pseudoshelia exhibiting an excellent deodorizing effect. -It has been clarified that Boydy, Scopariopsis brebicauris, Petriella Setiffera, etc. show high homology of 98% or more. Therefore, it is considered that Pseudoshelia boidi, Scoopariopsis brevikauris, Petriella cetiffera, etc. can exhibit an excellent deodorizing effect as well as micro ascus silosus.

Among the filamentous fungi belonging to the genus Microascas, which are filamentous fungi according to the present invention, the DC2b strain is deposited with the depository as follows.
(I) Name and address of depositary organization Name: National Institute of Technology and Evaluation, Patent Microorganism Depositary Center Address: 2-5-8 Kazusa Kamashika, Kisarazu City, Chiba Prefecture
(Ii) Date of deposit: March 14, 2007 (iii) Deposit number: NITE P-337

  The deodorizer of the present invention may be composed only of volatile fatty acid-degradable filamentous fungi, and may further contain a solvent such as water.

  If the deodorizer of this invention is used, deodorization of organic sludge will be attained irrespective of the moisture content of organic sludge. In particular, it is possible to suppress the generation of odors of aldehydes peculiar to organic acids and dried sludge. Since the deodorizing agent of the present invention exhibits a deodorizing effect only by adding a very small amount to the organic sludge, the moisture content of the organic sludge is hardly increased by the combination of the organic sludge and the deodorizing agent. In addition, the content of halogen elements such as chlorine that causes equipment corrosion during combustion without causing a significant increase in the amount of inorganic components in organic sludge and a significant decrease in the amount of organic components that lead to a decrease in the amount of heat generated by sludge. Will not increase.

  Next, the deodorizing method of the present invention will be described. The deodorization method of the present invention includes a first step: a step of blending organic sludge and volatile fatty acid-degradable filamentous fungi, a second step: a step of culturing the filamentous fungus blended with sludge in the first step. It has features where it has.

  Examples of the filamentous fungus used in the deodorization method of the present invention include the filamentous fungus contained in the deodorizer of the present invention. Of the exemplified filamentous fungi, only one type may be used, or two or more types may be appropriately mixed and used.

  The organic sludge used in the present invention is not particularly limited as long as it contains an organic substance, and may contain an inorganic substance in addition to the organic substance. Examples of the organic sludge include sludge generated by sewage treatment, human waste treatment, treatment of organic wastewater generated from food factories and paper pulp factories, treatment of livestock waste such as livestock manure, and the like. These sludges may use only 1 type and may mix and use 2 or more types suitably.

  In each of the above treatments, various types of sludge are generated depending on the treatment process. However, the organic sludge used in the present invention is not limited by the treatment process. For example, primary sludge, excess sludge, mixed sludge Sludge, activated sludge, digested sludge, etc. can be used. Various chemicals such as a flocculant may be added to these sludges. These sludges may use only 1 type and may mix and use 2 or more types suitably.

  The water content of each sludge may be reduced by being subjected to various solid-liquid separation treatments and heat treatments. For example, concentrated sludge obtained by concentration treatment, dehydrated sludge obtained by dehydration treatment, dried sludge obtained by drying treatment, and the like can be used. In each treatment, various chemicals such as a flocculant may be added to the sludge. However, the organic sludge used in the present invention is preferably solid, and for example, dehydrated sludge and dried sludge are preferably used.

  The water content of the organic sludge used in the present invention is preferably 15% by mass or more, more preferably 25% by mass or more, and further preferably 30% by mass or more. If the water content is 15% by mass or more, the activity of the filamentous fungus can be increased, and an excellent deodorizing effect can be easily obtained. The upper limit of the moisture content is not particularly limited, but the moisture content is preferably 90% by mass or less from the viewpoint of easily obtaining solid sludge. The deodorizing method of the present invention is characterized in that it exhibits a deodorizing effect even with sludge having a low water content such as dried sludge and can also suppress odors of aldehydes newly generated by drying treatment. If the deodorization method of the present invention is specialized for such sludge deodorization, the moisture content is preferably 70% by mass or less, more preferably 60% by mass or less, and further preferably 50% by mass or less. The water content is measured by the loss on drying method of JIS K 0068.

  The pH of the organic sludge used in the present invention is preferably 5 or more, more preferably 6 or more, and even more preferably 6.5 or more. The pH is preferably 10 or less, more preferably 9.5 or less, and even more preferably 9 or less. If the pH is in the range of 5 or more and 10 or less, the activity of the filamentous fungus can be increased, and an excellent deodorizing effect can be easily obtained.

  The sludge pH is measured as follows. Distilled water having a mass 10 times the mass of sludge (wet state) is added to the sludge and stirred for 1 hour, followed by centrifugation at 6000 G and 4 ° C. for 10 minutes to obtain a supernatant. The pH of the obtained supernatant is measured with a pH meter using a glass electrode, and the value is taken as the pH of the sludge.

  The pH of the organic sludge varies depending on the wastewater and sludge generation source, the combination of treatment processes, the treatment method in each treatment process, and the like. For example, when a basic chemical such as lime is added to sludge in the dehydration treatment, the resulting dehydrated sludge tends to be alkaline. On the other hand, when an acidic chemical such as polyiron is added in the dehydration treatment, the resulting dewatered sludge tends to be acidic. Therefore, even if pH adjustment is not performed, when the pH of the organic sludge is in the range of 5 to 10, pH adjustment is not particularly required.

  When the pH of the organic sludge exceeds 10, an acidic chemical may be added to the organic sludge. Examples of the acidic agent include hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, sodium dihydrogen phosphate, potassium dihydrogen phosphate, boric acid, and the like. When the pH of the organic sludge is less than 5, a basic chemical may be added to the organic sludge. Examples of the basic drug include calcium oxide, calcium hydroxide, magnesium oxide, magnesium hydroxide, sodium hydroxide and the like.

  The pH adjustment of organic sludge can be done by adding chemicals for pH adjustment in any treatment process until organic sludge is obtained, changing the type and addition rate of chemicals already added, This may be done by stopping the addition. Further, a plurality of types of sludge having different pH may be mixed as appropriate to adjust the pH to a range of 5 to 10. You may adjust pH of the organic sludge obtained by changing a treatment process or selecting suitably the kind and quantity of the waste_water | drain provided for water treatment. Therefore, the method for adjusting the pH of the organic sludge used in the present invention is not particularly limited, and an appropriate method may be performed as necessary before the deodorizing method of the present invention.

  In the first step, the method of blending the organic sludge and the filamentous fungus is not particularly limited. For example, a method of adding the filamentous fungus to the organic sludge is shown. When adding the filamentous fungus, the form of the added filamentous fungus is not particularly limited. For example, the filamentous fungus may be added as a solid, or added as a suspension obtained by suspending the filamentous fungus in a solvent such as water. May be.

  As a method of blending organic sludge and filamentous fungi, a method of blending organic sludge and sludge containing volatile fatty acid-degradable filamentous fungi may be employed. For example, using sludge that already contains organic sludge and filamentous fungus as seed sludge, adding seed sludge to organic sludge, adding organic sludge and filamentous fungus to seed sludge, etc. It is done. In this case, since it is not necessary to add the filamentous fungus to the organic sludge in an isolated state, the operation during the deodorization treatment becomes easy.

  When the filamentous fungus is added to the organic sludge as a suspension, the deodorizing effect is exhibited even if the filamentous fungus suspension is added to less than 1 part by mass with respect to 100 parts by mass of the organic sludge. Moreover, when adding organic sludge to seed sludge, the moisture content of organic sludge does not change substantially. Therefore, in the deodorizing method of the present invention, the moisture content of the sludge hardly increases or does not substantially change due to the addition of the deodorizing agent.

  The deodorizing method of the present invention may be performed by any processing method such as batch processing or continuous processing.

  In the case of batch processing, the method of blending organic sludge and filamentous fungi is, for example, a method of adding filamentous fungus to organic sludge, or sludge that has already been blended with organic sludge and filamentous fungus as seed sludge. And a method of adding seed sludge to organic sludge. In this case, after blending organic sludge and filamentous fungi, deodorized sludge can be obtained by culturing the filamentous fungi blended in organic sludge for a predetermined period. The sludge in which organic sludge and filamentous fungus are blended may be left as it is without culturing at the time of culture, or may be appropriately stirred.

  In the case of continuous treatment, the method of blending organic sludge and filamentous fungi is, for example, using sludge that is already blended with organic sludge and filamentous fungus as seed sludge, and adding organic sludge to seed sludge. Examples thereof include a method of adding organic sludge and filamentous fungi to seed sludge. In this case, it is preferable that seed sludge is always present in the culture system for culturing the filamentous fungus. For example, a method of adding a certain amount of organic sludge to the culture system in the presence of seed sludge and extracting a certain amount of sludge from the culture system as deodorized sludge is shown.

  In the case of continuous treatment, the operation of adding organic sludge to the culture system and the operation of extracting sludge from the culture system may be performed simultaneously or at different timings. Moreover, the operation of adding organic sludge to the culture system and the operation of extracting sludge from the culture system may each be performed continuously or may be appropriately performed at a necessary timing.

  In the case of continuous treatment, the culture may be performed under conditions such that the culture system is completely mixed, and so-called plug flow in which sludge added to the culture system is sequentially moved to the discharge side and pulled out from the culture system. You may culture | cultivate on these conditions. Also, intermediate conditions between complete mixing and plug flow, for example, plug flow as a whole, but with conditions such as partial mixing by appropriately performing partial stirring, etc. Culture may be performed.

  The culture temperature is preferably 15 ° C or higher, more preferably 25 ° C or higher, and further preferably 30 ° C or higher. The culture temperature is preferably 45 ° C. or lower, more preferably 42 ° C. or lower, and further preferably 37 ° C. or lower. If culture | cultivation temperature is 15 degreeC or more and 45 degrees C or less, the activity of a filamentous fungus can be made high and it will become easy to acquire the outstanding deodorizing effect. In addition, culture | cultivation temperature means the temperature of the organic sludge at the time of culture | cultivation.

  When the culture temperature is less than 15 ° C., the culture temperature may be appropriately adjusted using a heating means. For example, a heating means is placed inside the organic sludge, a heating means is placed outside the container where the organic sludge is placed during cultivation, and the sludge is indirectly heated from the outside, or the organic sludge is placed during cultivation. The culture temperature may be increased by introducing heated air into the atmosphere. When the culture temperature exceeds 45 ° C., the culture temperature may be appropriately adjusted using a cooling means. For example, a cooling means is arranged inside the organic sludge, a cooling means is arranged outside the container where the organic sludge is placed during cultivation, and the sludge is indirectly cooled from the outside, or the organic sludge is removed during the cultivation. What is necessary is just to introduce | transduce cooling air or external air into the atmosphere to be put, and to reduce culture | cultivation temperature.

  There is no particular limitation on the environment in which the sludge containing the filamentous fungus and the organic sludge is placed during the culture. The sludge in which the filamentous fungus and the organic sludge are blended may be disposed so as to be opened to the atmosphere, for example, or the organic sludge may be disposed in the sealed container. When arrange | positioning the said sludge in an airtight container, you may replace suitably the air in a container by ventilation | gas_flowing etc.

  The culture period may be appropriately adjusted according to the moisture content of the organic sludge, the pH of the organic sludge, the blending ratio of the organic sludge and the filamentous fungus, the culture temperature, the desired deodorizing effect, and the like. However, the culture period is preferably 1 day or longer, more preferably 2 days or longer, and even more preferably 4 days or longer. By setting the culture period to 1 day or longer, an excellent deodorizing effect can be easily obtained. In the batch treatment, the culture period means the time from when organic sludge and filamentous fungi are blended to the time of exiting from a culture area such as a culture apparatus or a culture facility. In the continuous treatment, the culture period means the sludge residence time in the culture area. The sludge residence time is calculated from (the amount of sludge in the area for culturing) / (the amount of sludge per day extracted from the area for culturing).

  The deodorizing method of the present invention may further include a step of heating the sludge obtained in the second step as the third step. By adding the process of heating the sludge, the odor of the obtained sludge is further reduced, and the moisture content of the sludge is reduced, thereby expanding the application range of the sludge.

  The moisture content of the sludge obtained in the third step is preferably 10% by mass or less, more preferably 5% by mass or less, and further preferably 3% by mass or less. If the moisture content is 10% by mass or less, the odor of the obtained sludge is further reduced and the application range of the sludge is expanded. For example, when the deodorized sludge obtained by the deodorizing method of the present invention is used as a solid fuel, it is particularly preferable that the sludge has a low moisture content because the calorific value based on the sludge mass (wet state) increases.

  The method for heating the sludge is not particularly limited, and a known sludge drying method can be used.

  The heating temperature and the heating time are not particularly limited as long as the moisture content of the sludge can be reduced. However, the heating temperature is preferably 60 ° C or higher, more preferably 100 ° C or higher, and further preferably 130 ° C or higher. The heating temperature is preferably 250 ° C. or lower, more preferably 200 ° C. or lower, and further preferably 180 ° C. or lower. If heating temperature is 60 degreeC or more, a water | moisture content can be efficiently removed from sludge and it becomes easy to further suppress the odor of the obtained sludge. If heating temperature is 250 degrees C or less, it will become easy to remove a water | moisture content from sludge, without causing carbonization and combustion of sludge. In addition, what is necessary is just to adjust a heating time suitably according to a heating temperature, the moisture content which the sludge obtained obtains, etc. desired.

  Since the odor of the deodorized sludge obtained by the deodorizing method of the present invention is greatly reduced, the handleability and work environment of the sludge are improved. Moreover, the moisture content of sludge hardly increases by a deodorizing process, and if the heat processing of a 3rd process is combined, the sludge with which the moisture content fell can be obtained. Furthermore, when pH adjustment of organic sludge is unnecessary or even when pH adjustment is required, if an appropriate chemical is selected, a significant increase in the amount of inorganic components and a significant increase in the amount of organic components that will lead to a decrease in the amount of heat generated by sludge. It is possible to obtain deodorized sludge that does not decrease and that does not increase the content of halogen elements such as chlorine, which cause equipment corrosion during combustion. Therefore, the deodorized sludge obtained by the deodorizing method of the present invention can be particularly suitably used as a solid fuel.

  The solid fuel containing the deodorized sludge obtained by the deodorizing method of the present invention may be used alone as a fuel, or may be used by mixing with other fuels. Since the solid fuel of the present invention has a carbon neutral property, it is particularly effective to use it as a substitute for fossil fuel. For example, it can be used as an alternative to coal, which is a solid fossil fuel, in a coal-fired power plant or an industrial boiler that uses coal as fuel.

  Hereinafter, the present invention will be described in more detail with reference to examples, but the scope of the present invention is not limited thereto.

<Analysis method>
[Measurement method of moisture content of sludge]
The moisture content of the sludge was measured by the loss on drying method of JIS K 0068. That is, the sludge was dried at 105 ° C. by a blow type constant temperature dryer, and the mass reduction rate at that time was defined as the moisture content. The drying time was 14 hours.

[Measurement method of loss on ignition of sludge]
The loss on ignition of sludge was measured according to JIS K0067. That is, the sludge dried at 105 ° C. was heated in a muffle furnace at 600 ° C. for 2 hours, and the weight reduction ratio at that time was defined as ignition loss.

[Measurement method of sludge pH]
Distilled water having a mass 10 times the mass of sludge (wet state) was added to the sludge, stirred for 1 hour, and then centrifuged for 10 minutes at 6000 G and 4 ° C. to obtain a supernatant. The pH of the obtained supernatant was measured with a pH meter using a glass electrode, and the value was defined as the sludge pH.

[Measurement method of organic acid and aldehyde content in sludge]
Distilled water having a mass 10 times the mass of sludge (wet state) was added to the sludge, stirred for 1 hour, and then centrifuged for 10 minutes at 6000 G and 4 ° C. to obtain a supernatant. The obtained supernatant was filtered using a 0.22 μm membrane filter to obtain a filtrate. In Experiment 1, the organic acid contained in the filtrate was measured by high performance liquid chromatography equipped with an electrical conductivity detector as a detector. The high performance liquid chromatography analysis was performed according to JIS K 0124. In Experiment 2, the organic acid contained in the filtrate was measured by a gas chromatograph equipped with a flame ionization detector (FID) as a detector. The gas chromatograph analysis was performed according to JIS K 0114. The aldehyde contained in the filtrate was measured by gas chromatography mass spectrometry. Gas chromatograph mass spectrometry was performed according to JIS K 0123.

[Sludge olfactory test method]
2 g of sludge was placed in a 50 mL capacity plastic container, and a plastic container containing sludge was placed 3 cm away from the nose to smell it.

(1) Experiment 1: Batch experiment [Production Example 1]
The dehydrated sludge having a water content of 82.4% by mass and an ignition loss of 81.8% by mass obtained by dehydrating the mixed raw sludge generated by the sewage treatment is dried at 60 ° C. for 6 hours by a blow type constant temperature dryer. A dried sludge having a water content of 43.4% by mass was obtained. On the other hand, Microascus cirrosus (Independent Administrative Institution Product Evaluation Technology Organization Patent Microorganism Deposit Center Accession Number: NITE P-337) is changed to YM (0.3% Yeast extract, 0.3% Malt extract, 0.5% Peptone, 1 % Glucose) The filamentous fungus obtained by culturing on the agar medium was suspended in 10 mL of distilled water so that the OD ₆₀₀ was 1.0 to prepare a filamentous fungus suspension. 30 g of the dried sludge was lightly crushed with a table mill, and 200 μL of the filamentous fungus suspension was added thereto to make sludge 1. The sludge 1 was dried at 60 ° C. for 6 hours with a blow type constant temperature dryer to a moisture content of 2.4% by mass, and the sludge 1 was used as a sample for an olfactory test.

[Production Example 2]
The sludge 1 was charged into a 500 mL plastic container, the container was covered, and cultured at 30 ° C. for 4 days. The resulting sludge was used as sludge 2. During the culture, the container lid was opened once a day to change the air, and the sludge was lightly stirred. The sludge 2 is used as it is as a sample for measuring the organic acid and aldehyde content, and the sludge 2 is further dried at 60 ° C. for 6 hours by a blow type constant temperature dryer to have a moisture content of 2.0 mass%. Used as a sample.

[Production Example 3]
In Production Example 1, quick lime was added to dehydrated sludge in an amount of 0.63% by mass with respect to the sludge mass (wet state), mixed, and dried at 60 ° C. for 6 hours with a blow type constant temperature dryer. The same operation as 1 and 2 was performed to obtain sludge 3. Quicklime was used as a pH adjuster for sludge. In the olfactory test of the sludge 3, the sludge 3 having been subjected to a drying treatment in the same manner as in Production Example 2 to a moisture content of 1.9% by mass was used as a test sample.

[Production Example 4]
In Production Example 1, quick lime was added to dehydrated sludge in an amount of 1.25% by mass with respect to the sludge mass (wet state), mixed, and dried at 60 ° C. for 6 hours with a blow type constant temperature dryer. The same operation as 1 and 2 was performed to obtain sludge 4. Quicklime was used as a pH adjuster for sludge. In the olfactory test of the sludge 4, the sludge 4 was subjected to a drying treatment in the same manner as in Production Example 2 to a moisture content of 2.2% by mass as a test sample.

<Measurement results>
The measurement results of the organic acid and aldehyde contents of sludges 1 to 4 are shown in Table 1. In Table 1, the organic acid and aldehyde content represents the content per sludge dry mass. The sludge dry mass means the mass of sludge that has been dried at 105 ° C. for 14 hours or more in a blow type constant temperature dryer.

  Sludge 1 is sludge in which filamentous fungi are simply blended with organic sludge, and the number of culture days is 0 days. In sludge 2 cultured for 4 days using sludge 1, the contents of organic acids and aldehydes partially decreased. In the sludges 3 and 4 cultured after adjusting the pH, the contents of organic acids and aldehydes were significantly reduced.

  Table 2 shows the olfactory test measurement results of sludges 1 to 4. As a result of the olfactory test of sludge, the generation of clear odor was recognized in the sludges 1 and 2, but the odor perceivable by the odor was significantly reduced in the sludges 3 and 4.

(2) Experiment 2: Continuous experiment [Production Example 5]
Dehydrated mixed sludge generated by sewage treatment is dehydrated sludge with a water content of 80.3% by mass, loss on ignition of 82.9% by mass, and pH 5.4. 1.0% by mass was added and mixed, followed by drying at 105 ° C. for 4.0 hours with a blow type constant temperature dryer to obtain a dry sludge having a water content of 33.2% by mass and a pH of 8.1. 100g of the obtained dried sludge is lightly crushed by a table mill, and 10g of sludge 3 is added as seed sludge and mixed to obtain seed sludge mixed dried sludge, which is packed into a cylindrical glass column (φ50mm x 500mm). It was filled to a height of about 120 mm. The column filled with the seed sludge mixed and dried sludge was placed in an incubator maintained at 30 ° C., and cultured for a maximum of 112 hours while appropriately collecting sludge from the column for analysis. During the culture, wet air obtained by passing water through the bottom of the column was blown for 1 minute at a flow rate of 100 mL / min, and stopped for 1 minute. During the culture period, the water content of the mixed sludge mixed with seed sludge hardly changed.

[Production Example 6]
In Production Example 5, the same operation as in Production Example 5 was performed, except that the sludge 3 was not added to the dried sludge as seed sludge.

[Production Example 7]
In Production Example 5, drying was performed at 105 ° C. for 4.5 hours with a blow type constant temperature dryer to obtain a dried sludge having a moisture content of 27.8% by mass and a pH of 8.1, and the obtained dried sludge was mixed with seed sludge. Then, the same operation as in Production Example 5 was performed except that the cells were cultured for a maximum of 136 hours.

[Production Example 8]
In Production Example 7, the same operation as in Production Example 7 was performed, except that sludge 3 was not added as seed sludge to the dried sludge.

<Measurement results>
The measurement result of organic acid content of sludge obtained in Production Examples 5 and 6 is shown in FIG. 1, and the measurement result of organic acid content of sludge obtained in Production Examples 7 and 8 is shown in FIG. In addition, in each figure, organic acid content represents content per sludge dry mass. The sludge dry mass means the mass of sludge that has been dried at 105 ° C. for 14 hours or more in a blow type constant temperature dryer.

  From the result of FIG. 1, the organic acid content decreased in the sludge obtained in Production Example 5 to which seed sludge was added, compared to the sludge obtained in Production Example 6 in which seed sludge was not added, with a culture time of 16 hours. In the sludge obtained in Production Example 6, the organic acid content in the sludge hardly changed even at a cultivation time of 112 hours. In the sludge obtained in Production Example 5, the organic acid in the sludge was obtained in a cultivation time of 64 hours. Was almost decomposed.

  From the results of FIG. 2, the organic acid content decreased in the sludge obtained in Production Example 7 to which seed sludge was added, compared to the sludge obtained in Production Example 8 in which seed sludge was not added, with a culture time of 40 hours. In the sludge obtained in Production Example 8, the organic acid content in the sludge hardly changed even at a culture time of 136 hours. In the sludge obtained in Production Example 7, the organic acid in the sludge was obtained in a culture time of 136 hours. Was almost decomposed.

  The deodorization method and deodorizer of the present invention are used for deodorization of organic sludge generated by sewage treatment, human waste treatment, treatment of organic wastewater generated from food factories and paper pulp factories, treatment of livestock waste such as livestock manure, etc. Can be used.

It is an organic acid content measurement result (change of organic acid content for every culture time) of the sludge obtained by manufacture examples 5 and 6. It is an organic acid content measurement result (change of the organic acid content for every culture time) of the sludge obtained in Production Examples 7 and 8.

Claims (11)

1st process: The process of mix | blending organic sludge and a volatile fatty-acid decomposable filamentous fungus,
2nd process: The process of culturing the said filamentous fungus mix | blended with the organic sludge in the said 1st process. The deodorizing method of the organic sludge characterized by the above-mentioned.   The deodorization method according to claim 1, wherein Microascus cirrosus is used as the volatile fatty acid-degrading filamentous fungus.   The deodorization method according to claim 1 or 2, wherein the moisture content of the organic sludge is 15 mass% to 90 mass%.   The deodorizing method according to any one of claims 1 to 3, wherein the pH of the organic sludge is in the range of 5 to 10.   The deodorizing method according to any one of claims 1 to 4, wherein, in the second step, the filamentous fungus mixed with the organic sludge in the first step is cultured for 1 day or more.   The deodorizing method according to any one of claims 1 to 5, wherein in the second step, the culture is performed in a range of 15 ° C to 45 ° C.   Furthermore, the 3rd process: The deodorizing method of any one of Claims 1-6 which has the process of heating the sludge obtained at the said 2nd process.   The deodorizing method according to any one of claims 1 to 7, wherein in the first step, organic sludge and sludge containing volatile fatty acid-degradable filamentous fungi are blended.   A solid fuel comprising the deodorized sludge obtained by the method according to any one of claims 1 to 8.   A deodorizer for organic sludge, comprising a volatile fatty acid-degradable filamentous fungus.   The deodorizer for organic sludge according to claim 10, wherein the volatile fatty acid-degrading filamentous fungus is Microascus cirrosus.

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