JP4183738B1 - Method and apparatus for treating wastewater containing organic matter - Google Patents

Abstract

Disclosed is a wastewater treatment method that can sufficiently solubilize sludge to be retreated in an aeration tank with a weakly acidic hypochlorous acid aqueous solution and that does not affect the aeration tank.
SOLUTION: Sludge having a sludge concentration of 2000 to 30000 mg / L has a weakly acidic hypochlorous acid aqueous solution having an effective chlorine concentration of 500 to 15000 mg / L and a pH value of 4 to 7 of 100 to 3000 mg / L. So that the solubilization treatment is carried out. The solubilized sludge is returned to the flow rate adjustment tank, diluted with waste water, retained in the flow rate adjustment tank, and then sent to the aeration tank.
[Selection] Figure 1

Description

The present invention relates to a sludge volume reduction method and a volume reduction device. More specifically, the present invention relates to an aeration treatment process for treating activated water sludge using waste water containing organic matter using an aeration tank, and the aeration treatment process. A solubilization treatment step of solubilizing sludge by adding a weakly acidic hypochlorous acid obtained by mixing dilute hydrochloric acid to a sodium hypochlorite aqueous solution and causing the sludge generated by the operation to stay for a predetermined time while stirring; A method for treating wastewater containing organic matter, and a direct treatment method for carrying out this treatment method, comprising an aeration treatment step in which sludge solubilized by carrying out this solubilization treatment step is returned to the aeration tank and treated with activated sludge. The present invention relates to a processing apparatus.
Generally, wastewater containing organic matter is aerated. And the waste_water | drain after aeration process is guide | induced to a sedimentation tank, and is isolate | separated into sedimentation sludge and treated water in a sedimentation tank. Most of the precipitated sludge is returned to the aeration tank as return sludge and repeatedly aerated. On the other hand, part of the precipitated sludge is reduced in volume. The volume-reduced sludge is sent to the aeration tank and aerated again. A part of the precipitated sludge is discarded as excess sludge. Although the present invention can reduce the volume of general sludge, in particular, a method for treating wastewater containing organic substances characterized in that a part of the precipitated sludge as described above is subjected to volume reduction treatment, and the implementation of this treatment method. The present invention relates to a processing apparatus used directly.

The activated sludge method is known as one of the treatment methods for wastewater containing organic matter. This activated sludge method, as is well known in the art, supplies floating organic sludge inhabited by aerobic bacteria, protozoa, etc., that is, activated sludge to the aeration tank, and supplies sufficient air and contains organic matter to be treated. This is a method in which wastewater is introduced and organic matter contained in the wastewater is preyed on by microorganisms such as aerobic bacteria that inhabit the activated sludge. The mixture of water and activated sludge treated in the aeration tank flows down to the settling tank, where it is separated into activated sludge and treated water. Treated water is discharged into public water areas. The sedimented activated sludge is returned to the aeration tank as return sludge. According to this method, the organic matter in the wastewater is decomposed into water and carbon dioxide gas, so that there is an advantage that treated water containing almost no organic matter can be obtained.
However, since microorganisms such as aerobic bacteria grow in a large amount in the aeration tank, if left as it is, the activated sludge increases too much and the activated sludge and the treated water cannot be separated in the sedimentation tank. Therefore, surplus activated sludge generated by the aeration process is periodically extracted as surplus sludge from the settling tank. The extracted excess sludge is made into a dehydrated cake by, for example, a dewatering device, and after being subjected to a process such as incineration, it is appropriately disposed of in a disposal site or the like. By the way, such disposal sites are becoming scarce in recent years, and the treatment cost of surplus sludge has risen, and further, there is a problem of generation of harmful substances such as dioxin accompanying incineration, so the volume of surplus sludge is strongly reduced. It has been demanded. Further, in such excess sludge, a large amount of untreated organic matter and bacteria that should be decomposed into water and carbon dioxide gas remain. There is a demand for a technique for properly decomposing organic substances contained in these sludges.

JP-A-2005-305222 JP 2007-209889 A

  Patent Document 1 describes a method for reducing the volume of sludge by adding ozone to the sludge extracted from the settling tank and returning it to the aeration tank again. When ozone is added to the sludge, the cell walls of microorganisms constituting the sludge are destroyed by oxidation and the cytoplasm inside the cells is eluted, or so-called sludge solubilization occurs in which aggregates of microorganisms, that is, flocs are subdivided. Since the solubilized sludge is easily engulfed by microorganisms such as bacteria, it can be returned to the aeration tank again for the activated sludge treatment. Thereby, it is said that sludge can be reduced in volume. Patent Document 1 also describes a method for promoting solubilization of sludge by adding sodium hypochlorite as an oxidizing agent, that is, sodium hypochlorite, in addition to ozone.

  The explanation of the sludge volume reduction mechanism of Patent Document 1 seems to be insufficient, and a supplementary explanation is as follows. That is, the activated sludge contains not only bacteria but also biologically degradable organic substances and inorganic substances. In activated sludge that has been subjected to aeration for a long time, bacteria are only a part of the whole. Of course, inorganic materials cannot be reduced in volume by an oxidizing agent such as ozone. Microorganisms such as bacteria and biologically indegradable organic substances are objects of sludge volume reduction. Microorganisms can be greatly reduced by long-term aeration. In fact, many wastewater treatment facilities use the long-time aeration method. This is done to reduce the volume of sludge, and the excess sludge becomes a fraction of that when treated by the standard method. From the above, it can be said that the problem of volume reduction is a biodegradable organic substance.

  Also by the sludge volume reduction method described in Patent Document 1, it is possible to solubilize the sludge and perform the activated sludge treatment again in the aeration tank, so that the effect of reducing the sludge volume is recognized. However, there are problems. For example, since a large amount of ozone is required to solubilize sludge, it is necessary to provide a particularly large ozone generator. Further, in order to generate a large amount of ozone, a large amount of electric power is required, and there is a problem that both initial cost and running cost are increased.

Therefore, a sludge volume reduction method in which sludge is solubilized with sodium hypochlorite instead of ozone is also conceivable. According to this method, an expensive ozone generator is not required, and inexpensive sodium hypochlorite can be used, so that the initial cost and running cost can be reduced. However, sodium hypochlorite has the following four problems, and it is difficult for those skilled in the art to adopt sodium hypochlorite instead of ozone.
[Problem 1] sodium hypochlorite (NaOCl) is mostly in water negative ions (ClO ^-) present in, is stabilized. Therefore, at the time of storage, it is made 12% (120,000 mg / L) or 6% chlorine concentration, made alkaline and 100% ionized. In other words, being stable means low reactivity. When ionized, they repel each other negatively charged microorganisms in the sludge and cannot effectively sterilize and oxidize the microorganisms. That is, sodium hypochlorite has the problem of low reactivity because it is ionized under alkaline conditions.
In the case of normal use, for example, when hypochlorous acid is injected into tap water, the chlorine concentration is reduced to about 1 mg / L and greatly diluted, so that it becomes close to the pH of tap water before disinfection, and the alkalinity decreases. . However, when it is desired to efficiently reduce the volume of sludge, the chlorine concentration may be 100 mg / L or more, so that the pH becomes high and alkaline.
[Problem 2] Therefore, most of sodium hypochlorite remains without being consumed and mixed into the downstream aeration tank, and there is a high possibility that it will adversely affect important microorganisms in the aeration tank. Such residual chlorine consists of free chlorine in which chlorine (Cl ₂ ) and hypochlorous acid (HOCl) coexist in an equilibrium state, and chloroamines combined with ammonia, that is, bonded chlorine. When strong free chlorine is mixed into the aeration tank, the effect is particularly worrisome.
[Problem 3] When sodium hypochlorite reacts with an organic substance, a harmful substance trihalomethane is generated.
[Problem 4] The oxidizing power of sodium hypochlorite is weaker than that of ozone, the biologically indegradable organic matter and microorganisms that make up the sludge are not destroyed, and the sludge may not be sufficiently reduced in volume. .

  Although the aqueous solution of sodium hypochlorite shows weak alkalinity, as described in Patent Document 2, the present inventors added an acid to sodium hypochlorite so that it was weakly acidic at pH 4-7. We propose a method for reducing excess sludge by solubilizing sludge and then treating activated sludge to reduce sludge. When the sodium hypochlorite solution is made weakly acidic, the problems 1 to 3 described above are solved to some extent as described below. The actual data shows that the volume of sludge has been sufficiently reduced, and the concern pointed out in Problem 4 has been dispelled.

An aqueous solution in which sodium hypochlorite (NaOCl) is dissolved in water with the equivalent amount of hypochlorous acid necessary for solubilization of sludge exhibits weak alkalinity near pH 9, and sodium hypochlorite is a non-ionized molecule (HOCl ) And hypochlorite ion (OCl ⁻ ) maintain a chemical equilibrium represented by the following formula.
HOCl ⇔ H ^{+ +} OCl ^-
The concentration of non-ionized hypochlorous acid (HOCl) is about 3% in the region R1 near pH 9, as shown in the concentration curve in FIG. It has become ^- chlorite ion (OCl). Therefore, even if such a sodium hypochlorite aqueous solution is added to the sludge as it is, as pointed out in the first problem, hypochlorite ions are stabilized and the concentration of hypochlorous acid is low and the reaction is weak. . In addition, it is difficult to act on negatively charged microorganisms, and only about 3% of non-ionized hypochlorous acid substantially acts on sludge and is not sufficiently oxidized. Unconsumed hypochlorite ions gradually change to hypochlorous acid with sterilizing and oxidizing action while maintaining concentration equilibrium, and are slowly consumed. However, since hypochlorite ions are stabilized and take a long time, as pointed out in the second problem, hypochlorite ions are mixed in the aeration tank without being consumed and have an adverse effect.

  The weakly acidic hypochlorous acid described in Patent Document 2, that is, the biomaster liquid (BM liquid) is obtained by adding dilute hydrochloric acid (HCl) to sodium hypochlorite aqueous solution. In such a biomaster solution, as shown in a region R2 in FIG. 2A, the concentration of non-ionized hypochlorous acid is 80% or more. Therefore, when the biomaster liquid is added to the sludge, hypochlorous acid efficiently oxidizes by acting on microorganisms and biodegradable organic substances. As the reaction proceeds, hypochlorous acid changes to hydrochloric acid, and the pH decreases. Reducing the pH further improves the reactivity because the ratio of hypochlorous acid approaches 100%. Even if the pH of the sludge is high and the pH exceeds 7 when the biomaster solution is added, the pH decreases to 7 or less as the reaction proceeds and the reaction accelerates. Further, since hypochlorous acid is efficiently consumed, the possibility that hypochlorous acid is mixed into the aeration tank is relatively low. Therefore, the problem 1 is solved and the risk of the problem 2 is low. Further, under mild acidity, the risk of hypochlorous acid reacting with organic matter to produce trihalomethane is much less than under alkaline, and the risk of problem 3 is also low.

  Although not described in Patent Document 2, after 70 days of solubilization of sludge with a biomaster solution using a test plant, the sludge was returned to the aeration tank and reprocessed. As shown, it has been confirmed that the amount of sludge generated is about 11 to 21% before the biomaster liquid is added. That is, despite the concerns pointed out in Problem 4, it was confirmed that sludge was significantly reduced in volume. As pointed out in Problem 4, hypochlorous acid, which is the main component of the biomaster liquid, has lower oxidizing power than ozone, but has sufficient oxidizing power to reduce sludge volume. There was found. The sludge treated with the biomaster liquid is decomposed again in the aeration tank and treated with activated sludge. Thus, hypochlorous acid in the biomaster liquid partially oxidizes and destroys biodegradable organic substances and microorganisms. When this is returned to the aeration tank, the partially broken organic matter is decomposed into bacteria and the like as biodegradable organic matter. In addition, the broken cells are rapidly preyed on by other microorganisms. The biomaster liquid thus plays a role of partial oxidative degradation, and as a result, a small amount of oxidation produces a great result.

  The sludge volume reduction method described in Patent Document 2 also has the advantage that sludge can be solubilized with an inexpensive biomaster solution and activated sludge treated in an aeration tank to significantly reduce the sludge volume. In addition, the amount of hypochlorous acid remaining in the solubilized sludge returned to the aeration tank is small and relatively safe. However, problems to be improved are also recognized.

That is, the sludge volume reduction device described in Patent Document 2 is provided with a hypochlorous acid reaction tank, that is, a biomaster reaction tank, which is solubilized by adding a biomaster liquid to the extracted precipitated sludge. However, since no special consideration is taken when the solubilized sludge is returned to the aeration tank, some of the hypochlorous acid in the biomaster liquid remains untreated and contains solubilized residual chlorine. The risk that sludge is returned to the downstream aeration tank and adversely affects microorganisms such as precious bacteria in the aeration tank is not completely eliminated. In particular, since there is no consideration about the possibility that free chlorine having strong sterilizing power is returned to the aeration tank, it cannot be said that safety is sufficiently guaranteed. In order to prevent residual chlorine from being mixed into the aeration tank, a conventionally known reducing agent such as sodium thiosulfate (Na ₂ S ₂ O ₃ ) or sodium sulfite (Na ₂ SO ₃ ) is injected into the solubilized sludge so that the residual chlorine Hydrogen sulfide (H ₂ S), which has high chemical costs, is anaerobically decomposed when sludge is dehydrated in the future, and has a harmful and decaying odor from the sulfur contained in the reducing agent. Is not preferable.

  In addition, fats and oils or oil components may be mixed in the wastewater containing organic matter, but the mixed oil components aggregate and float on the surface of the wastewater, and prey to microorganisms in the aeration tank. Is difficult. Since such a fat and oil mass has a small specific gravity and is difficult to precipitate, it cannot be extracted and solubilized in the precipitation tank as a precipitated sludge. In the sludge volume reduction method described in Patent Document 2, no special consideration is given to the treatment of waste water containing such fats or oil components.

  The present invention has been made in view of the above-described problems. Specifically, when solubilizing sludge produced by activated sludge treatment, the biomaster liquid, ie hypochlorous acid, is cheaper and easier to handle. Despite the use of weakly acidic hypochlorous acid obtained by mixing dilute hydrochloric acid with an aqueous acid soda solution, free chlorine is reliably consumed without the need to inject a reducing agent. It is an object of the present invention to provide a method for treating wastewater containing organic substances and a treatment apparatus used for the implementation of this method, the concentration of which becomes sufficiently low and does not possibly adversely affect the subsequent activated sludge treatment. Further, in addition to the above-mentioned object, another invention includes an organic substance that can efficiently decompose and treat the organic substance in the wastewater even if the fat or oil component is contained in the wastewater containing the organic substance. It aims at providing the processing method and processing apparatus of waste water.

In order to achieve the above object, the present invention provides a weakly acidic hypochlorous acid aqueous solution having an effective chlorine concentration of 500 to 15000 mg / L and a pH value of 4 to 7 with respect to sludge having a sludge concentration of 2000 to 30000 mg / L. When solubilizing by adding 100 to 3000 mg / L, the sludge sludge is supplied in the most upstream reaction tank among the solubilization devices composed of a plurality of reaction tanks provided in series. A weakly acidic hypochlorous acid aqueous solution is added and stirred, and the mixture is stirred while being sequentially fed to the downstream reaction vessel, and the reaction is carried out over 5 minutes. And it is comprised so that the sludge solubilized in the flow control tank may be diluted with waste water containing organic matter and returned to the aeration tank after 5 to 24 hours. Since it is diluted with wastewater containing organic matter after solubilization treatment, free chlorine of residual chlorine reacts and is consumed quickly, and the concentration of combined chlorine and hydrochloric acid can be reduced to predetermined concentrations. As the acid to be added to sodium hypochlorite, various acids such as acetic acid and sulfuric acid can be used in addition to hydrochloric acid, but hydrochloric acid is the most preferable. Therefore, in the present invention, all are described as hydrochloric acid. The sludge to be reduced in volume is not limited to excess sludge. In the activated sludge method, there is a limit to sludge volume reduction with surplus sludge alone. A part of aeration tank sludge and a part of return sludge are targeted to increase the amount of treatment. Moreover, another invention is comprised so that an activated sludge process, a solubilization process, etc. may be implemented by adding surfactant to the waste_water | drain containing organic substance.

That is, a first aspect of the present invention, in order to achieve the above object, the aeration step of the activated sludge process the raw wastewater containing organic matter using aeration tank, generated by the implementation of the aeration step To the sludge to be added, a weakly acidic hypochlorous acid aqueous solution having an effective chlorine concentration of 500 to 15000 mg / L and a pH value of 4.0 to 7.0 obtained by mixing dilute hydrochloric acid with sodium hypochlorite aqueous solution is added And solubilizing the sludge by allowing the sludge to stay for a predetermined time while stirring without aeration, and diluting the sludge solubilized by the solubilization treatment step with wastewater to be treated containing organic matter. Each step consists of a dilution step, a retention step for retaining the solubilized and diluted sludge for a predetermined time, and an aeration treatment step for treating the activated sludge by returning the solubilized, diluted and retained sludge to the aeration tank. continuous real While, the solubilization treatment step, among the plurality of reaction vessels provided in series, the reaction vessel most upstream side, to supply the sludge Sludge concentration 2000~30000mg / L, the weak of the concentration hypochlorous acid solution of the acid is added and stirred so as to chlorine concentration 100 to 3000 / L, sequentially feed to the downstream side of the reaction vessel below also agitated in these reactions layer, 5 minutes as a whole It implements over the above , The said dilution process and a residence process are comprised so that it may implement over 5 to 24 hours in a flow control tank .

Further, the invention according to claim 2 is the treatment method according to claim 1, wherein the sludge solubilized by the solubilization treatment step is a part of the sludge obtained by performing the aeration treatment step, and the remaining sludge The sludge is configured to be returned to the aeration tank to be treated with activated sludge. The invention according to claim 3 is the treatment method according to claim 1 or 2, wherein the wastewater to be treated containing organic matter is treated with coconut oil fatty acid. Each of the steps is performed by adding a surfactant composed of an ester or ether mainly composed of

The invention of claim 4 includes a flow rate adjusting tank the raw wastewater from staying containing organic matter, the aeration tank for activated sludge treatment of raw wastewater containing the organic substance flowing from the flow regulation tank, The settling tank comprises a settling tank for separating the sludge treated by the aeration tank from the treated water, and a solubilization reaction apparatus for solubilizing the sludge drawn from the settling tank without aeration. consists plurality of reaction vessel stirring device is provided, these reactors are arranged in series, the reaction vessel most upstream side, and a portion of the sludge withdrawn from the settling tank, hypochlorite aqueous solution of sodium being adapted to the weakly acidic aqueous solution of hypochlorous acid obtained by mixing the dilute hydrochloric acid is added to the sludge and aqueous solution of hypochlorous acid fed to the reaction vessel of the most upstream side is sequentially To be sent to the downstream reactor Is configured, the reaction vessel of the most downstream side of the reaction vessel, which is connected to the flow regulation tank, the sludge which has been solubilized, the flow rate residual chlorine concentration by the raw wastewater containing organic matter in the adjustment tank 3 mg / L It is configured as a wastewater treatment apparatus containing organic matter that is diluted to a dilution rate that becomes the following, and the invention according to claim 5 is the apparatus according to claim 4, The apparatus is configured as a wastewater treatment apparatus containing organic matter, to which treated wastewater containing an organic substance to which a surfactant composed mainly of coconut oil fatty acid is added is supplied.

As described above, according to the present invention, the weak chlorine acid having an effective chlorine concentration of 500 to 15000 mg / L and a pH value of 4 to 7 obtained by mixing dilute hydrochloric acid with sodium hypochlorite aqueous solution in the sludge solubilization treatment step. Since the hypochlorous acid aqueous solution is used, the initial equipment cost and the running cost can be reduced as compared with the case of solubilization with ozone or ozone water. And since sludge solubilization is carried out while sequentially sending the plurality of reaction tanks provided in series to the downstream side, continuous operation is possible. In particular, when processing in batch mode, the reaction tank becomes large and the equipment cost is high, and it is difficult to control the supply and stop of sludge and hypochlorous acid aqueous solution, but according to the present invention, continuous operation is possible. As a result, the reaction tank becomes inexpensive, and the effect of simplifying the control of supply and stop of sludge and hypochlorous acid aqueous solution can be further obtained. Furthermore, this invention is comprised so that it may dilute with the waste_water | drain containing an organic substance after solubilizing sludge. Therefore, even if residual chlorine remains in the solubilized sludge, free chlorine with strong bactericidal activity reacts with organic matter quickly and is consumed, and combined chlorine is diluted and the concentration of residual chlorine decreases. Even if the reducing agent is not particularly injected into the solubilized sludge, there is no possibility of adversely affecting the aeration tank, and an effect unique to the present invention can be obtained that the activated sludge treatment can be performed in the aeration tank. In addition, as will be described in detail later, in the retention step in which the solubilized sludge is returned to the flow rate adjustment tank and diluted with the wastewater and retained , the combined chlorine is also consumed sufficiently by reacting with the organic matter in the wastewater. Therefore, the activated sludge treatment can be further safely performed.

  According to another invention, a surfactant is added to wastewater containing organic matter to perform an aeration treatment process, a solubilization treatment process, etc., so that the oil is emulsified and even if it contains oil, Similarly, the effect of being able to be decomposed and treated by microorganisms is obtained.

  Embodiments of the present invention will be described below. As shown in FIG. 1, the wastewater treatment apparatus containing organic matter according to the present embodiment is composed of an activated sludge treatment apparatus A, a sludge solubilization apparatus B, and a biomaster generation apparatus C. ing.

  As shown in the process flow diagram of FIG. 1, the activated sludge treatment apparatus A is schematically a flow rate adjustment tank 2 that receives wastewater containing organic substances from a wastewater supply pipe 1, and downstream of the flow rate adjustment tank 2. The aeration tank 3 provided on the side for biologically decomposing organic matter in the waste water, the precipitation tank 4 provided on the downstream side of the aeration tank 3 for separating sludge and treated water, and the like. The flow rate adjusting tank 2 has a drain supply pipe 1 connected to the drain inflow side, an aeration tank 3 connected to the discharge end, and a solubilized sludge feed mud pipe 29 and a biomaster auxiliary liquid injection pipe 40 connected. Has been. As will be described in detail later, the solubilized sludge is supplied from the solubilized sludge feed mud pipe 29 and the surfactant such as the biomaster auxiliary liquid is injected from the injection pipe 40 as necessary. ing. The flow rate adjusting tank 2 is a kind of buffer tank, and the waste water containing the organic matter supplied from the drainage supply pipe 1 is stagnation for a predetermined time in the flow rate adjusting tank 2 to be uniformed and controlled to an appropriate flow rate. And sent to the aeration tank 3.

  As is well known in the art, the aeration tank 3 has a large number of air ejection holes at the bottom. Pressurized air is supplied from a blower provided outside these air holes. In the aeration tank 3, stirring blades are provided as necessary. A sedimentation tank 4 is connected to the discharge end of the aeration tank 3 configured in this way. In the aeration tank 3, microorganisms such as aerobic bacteria grow.

  The sedimentation tank 4 is configured as a sedimentation tank in which sludge is sedimented by gravity in the present embodiment, and has a funnel shape as a whole, and a sludge extraction pipe 5 for extracting the sedimentation sludge is connected to the lower end portion thereof. A measuring tank 6 is connected to the sludge extraction pipe 5. Although the specific structure of the measuring tank 6 is not shown in FIG. 1, it is comprised from the container which exhibits a box shape. The inside of the container is partitioned into a plurality of chambers by a plurality of partition plates provided with predetermined notches, and a triangular weir is formed in the partition plate on the most downstream side. Moreover, the sedimentation sludge extracted from the sedimentation tank 4 is supplied to the most upstream chamber. This uppermost chamber is provided with a gate that slides in the vertical direction, and the height position of this gate is adjusted to the set height. Precipitated sludge overflowing from this gate is returned to the aeration tank 3 by the sludge return pipe 7. Further, the sludge coming out of the triangular weir is sent to the sludge solubilizer B, which will be described in detail later, through a sludge supply pipe 26.

  The sludge solubilizer B according to the embodiment of the present invention may be constituted by only one reaction tank, but in the embodiment shown in FIG. It is comprised from the master reaction tanks 17 and 18. The two reaction tanks are connected in series to form a first-stage biomaster reaction tank 17 and a second-stage biomaster reaction tank 18 from the upstream. There is a predetermined level difference between the first-stage biomaster reaction tank 17 and the second-stage biomaster tank 18, which decreases toward the downstream side. Accordingly, when sludge is supplied to the first-stage biomaster reaction tank 17, the sludge staying in the first-stage biomaster reaction tank 17 is pushed out and connected to the second-stage biomaster reaction tank 17 via the connection pipe 21. Mud is sent to the biomaster reaction tank 18. The biomaster reaction tanks 17 and 18 are provided with stirring blades 24 and 24, respectively, and the sludge in the tanks is appropriately stirred. The stirring device need not be a stirring blade, and may be stirred by a sludge pump or the like.

  Above the first-stage biomaster reaction tank 17, a sludge supply pipe 26 and a biomaster liquid injection pipe 27 piped from the biomaster liquid generator 12 are opened. Through these pipes 26 and 27, sludge is supplied into the first-stage biomaster reaction tank 17 and a biomaster solution is injected. A solubilized sludge feed mud pipe 29 is connected to the second-stage biomaster reaction tank 18 so that the solubilized sludge is returned to the flow rate adjustment tank 2. According to the present embodiment, the monitoring pH meter 31 is provided in the first-stage biomaster reaction tank 17 on the most upstream side of the reaction tank configured as described above. Although not shown in FIG. 1, the second-stage biomaster reaction tank 18 is provided with a pH meter and an oxidation-reduction potentiometer, that is, an ORP meter, solubilized sludge by these instruments. PH and oxidation-reduction potential are measured, and it is possible to monitor whether or not the treatment is properly performed. It should be noted that in order to ensure safety in case a processing abnormality occurs due to equipment failure or the like, a second stage biomaster reaction tank 18 may be provided with a pH adjusting liquid or reducing agent inlet. Even when the treatment is normally performed, the reducing agent may be injected appropriately depending on the measured value of the oxidation-reduction potential, but this is not essential for the configuration of the present invention.

  According to the embodiment shown in FIG. 1, the biomaster liquid generator C is composed of a biomaster liquid generator 12, a sodium hypochlorite tank 14, a hydrochloric acid tank 15, and the like. For example, tap water is supplied from the water supply pipe 13 to the biomaster liquid generator 12, sodium hypochlorite is supplied from the sodium hypochlorite tank 14, and dilute hydrochloric acid is supplied from the hydrochloric acid tank 15. A biomaster liquid having a predetermined concentration is produced. The sodium hypochlorite tank 14 and the hydrochloric acid tank 15 are appropriately replenished with sodium chlorite and dilute hydrochloric acid from the respective chemical tanks 14 'and 15'.

  Next, the operation of the wastewater treatment apparatus including organic matter according to the present embodiment will be described. According to the present embodiment, since the system control panel, that is, the control device SC is provided, the supply amount of waste water containing organic matter, the return amount from the sludge settling tank 4 to the aeration tank 3, and the first-stage bio sludge Supply amount to the master reaction tank 17, sludge staying in the biomaster reaction tanks 17 and 18, start and stop of the pumps P and P provided in each pipeline, and intervening in each pipeline The operation of the open / close valves V, V is automatically controlled by the control device SC, but some of them can be operated manually. Moreover, the pH value, oxidation-reduction potential, etc. in the biomaster reaction tanks 17 and 18 are monitored by the controller SC. Hereinafter, in order to simplify the description, an example of manual operation instead of automatic operation by the control device SC will be described.

  A description will be given from the state of steady operation. When the waste water containing organic matter flows into the flow rate adjustment tank 2, the waste water stays in the flow rate adjustment tank 2 for about 5 to 24 hours, and then is controlled to an appropriate flow rate and sent to the aeration tank 3. In the aeration tank 3, it is treated with activated sludge as is conventionally known. That is, the air supplied from the blower is ejected in the form of bubbles to supply oxygen to the microorganisms in the activated sludge, so that the organic matter contained in the wastewater is preyed on by the microorganisms and decomposed into water and carbon dioxide. Since microorganisms divide and multiply, the propagated microorganisms form flocs together with undegraded organic matter, etc., and become new sludge. The sludge generated in this way is sent to the next settling tank 4 together with the treated water.

  The flocculant is injected as needed at the precipitation tank inlet. Flock and the like aggregate and are separated into sludge and treated water due to the difference in specific gravity and gravity. By such separation, supernatant water, that is, treated water is obtained at a position above the settling tank 4. Since the treated water contains almost no organic matter, it is appropriately drained into rivers. On the other hand, the precipitated sludge is drawn out from the sludge extraction pipe 5 provided at the bottom of the settling tank 4 to the measuring tank 6.

  Since the gate of the measuring tank 6 is driven to a predetermined height, the settling sludge for a predetermined amount overflows from the triangular weir and is sent to the next sludge solubilizer B through the sludge supply pipe 26. On the other hand, the precipitated sludge overflowing the gate is returned from the sludge return pipe 7 to the aeration tank 3 as return sludge. Thereby, organic substance density | concentration is maintained appropriately and the activity of activated sludge does not fall. Other surplus sludge is sent to the surplus sludge storage tank 8, and after being dehydrated, it is appropriately transported to a disposal site or the like.

  When oil or fat or an oil component is contained in the waste water flowing into the flow rate adjusting tank 2 from the waste water supply pipe 1, an appropriate amount of a surfactant such as a bio master auxiliary liquid is supplied from the bio master auxiliary liquid supply pipe 40. This biomaster auxiliary liquid is an ester or ether mainly composed of coconut oil fatty acid. Since the biomaster auxiliary liquid has excellent surface activity, the agglomerated fats and oils are dispersed on the surface of the waste water, and are uniformly turbid or emulsified in the waste water. Therefore, microorganisms such as bacteria can efficiently decompose fats and oils.

  The solubilized sludge discharged from the measuring tank 6 is supplied to the first-stage biomaster reaction tank 17 of the sludge solubilizer B. At this time, the biomaster solution is also injected into the first-stage biomaster reaction tank 17.

  The biomaster liquid is generated by the biomaster liquid generator 12 as follows. It is produced by diluting 12% or less sodium hypochlorite aqueous solution and 35% hydrochloric acid to 9%, mixing them, and diluting with water so that the effective chlorine concentration becomes 500-15000 mg / L. Yes. When it is 15000 mg / L or more, handling becomes difficult. The biomaster solution thus produced is a weakly acidic hypochlorous acid aqueous solution having a pH value of 4.0 or more and less than 7.0. When the biomaster liquid is generated as described above, there is a danger that chlorine gas is generated when the pH value is 4.0 or less. Therefore, the pH must be checked when the biomaster liquid is generated.

  Such a biomaster liquid varies depending on the properties of sludge, suspended solids, that is, the concentration of SS, the degree to which the sludge is to be solubilized, etc. It injects into the biomaster reaction tank 17.

  In the first-stage biomaster reaction tank 17, the sludge and the biomaster liquid are stirred by the stirring blade 24. As already explained, hypochlorous acid in the biomaster liquid oxidizes and solubilizes biologically indegradable organic substances and bacteria in the sludge. The consumed hypochlorous acid is changed to dilute hydrochloric acid. The sludge that has been retained for a predetermined time in the first-stage biomaster reaction tank 17 and has been solubilized together with the biomaster liquid containing unconsumed hypochlorous acid from the connection pipe 21 to the second-stage biomaster reaction tank. 18 is sent. At this time, the inside of the tank is mixed by the stirring blade 24, and the sent sludge and the injected biomaster liquid are short-circuited and are not sent to the second-stage biomaster reaction tank 18, and are sufficiently reacted. After that, mud will be sent. However, even if the inside of the reaction vessel is completely mixed, there is a portion that flows out in a short time. This is unavoidable as long as it is continuous. As the number of reaction tanks increases, the portion that flows out in a shorter time is smaller. Therefore, it is preferable that a plurality of reaction tanks are implemented. In this embodiment, the reaction tank is composed of two reaction tanks.

  Similarly, in the second-stage biomaster reaction tank 18, the sludge and the biomaster liquid are stirred by the stirring blade 24. If it stays in the second-stage biomaster reaction tank 18 for a predetermined time, most of the hypochlorous acid is consumed and the sludge is sufficiently solubilized.

  Although hypochlorous acid in the biomaster liquid depends on the ratio of injection, most of it is consumed in 5 to 30 minutes, as is apparent from Example 1 described later. Accordingly, the sludge is allowed to stay in the biomaster reaction tanks 17 and 18 for 5 minutes or longer, preferably 30 minutes or longer. The required capacity of the biomaster reaction tanks 17 and 18 is determined according to the amount of sludge to be treated. If the installation space is sufficient, the capacity of the biomaster reaction tanks 17 and 18 may be increased, or three or more tanks may be provided so that the residence time is one hour or longer.

The sludge treated and solubilized in this manner usually consumes most of free chlorine and considerably consumes bound chlorine when it flows out of the second-stage biomaster reactor 18. However, depending on the injection ratio of the biomaster liquid and the residence time in the biomaster reaction tanks 17 and 18, it may remain slightly and may affect microorganisms in the aeration tank. It is particularly dangerous if free chlorine, which has a high bactericidal effect, enters the aeration tank. In order to ensure safety, it is necessary to surely consume free chlorine in the solubilized sludge and to sufficiently reduce the concentration of bound chlorine. For example, a conventionally known reducing agent such as sodium thiosulfate (Na ₂ S ₂ O ₃ ) or sodium sulfite (Na ₂ SO ₃ ) is injected into the solubilized sludge so as to completely decompose free chlorine and bound chlorine. However, as described above, the chemical cost of the reducing agent increases, and it is stored in the excess sludge storage tank 8 or is anaerobically decomposed when the sludge is dehydrated and included in such a reducing agent. Hydrogen sulfide (H ₂ S) that is harmful and has a rot odor is generated from the sulfur content, which is not preferable. Therefore, even if a reducing agent is used, it should be limited to the time when it is deemed necessary based on the measured values of the PH meter and ORP meter (or manual measurement) provided in the second-stage biomaster reaction tank 18. It is. In the present invention, consumption of residual chlorine remaining in the solubilized sludge is performed by the flow rate adjusting tank 2 described below, and safety is ensured.

  The solubilized sludge is returned to the flow rate adjustment tank 2 from the second-stage biomaster reaction tank 18 via the solubilized sludge feed mud pipe 29. When returned, the solubilized sludge is diluted with a large amount of wastewater containing organic matter. The solubilized sludge should contain almost no free chlorine, but even if it remains, it reacts with the organic matter in the wastewater and is quickly consumed. The residual chlorine remaining as bound chlorine also decreases in concentration according to the dilution ratio. Furthermore, combined chlorine is consumed by organic matter in the waste water. Since the fluidity of the wastewater is higher than that of the sludge, the solubilized sludge diluted with the wastewater has a high fluidity, and the reaction between the combined chlorine and the organic matter takes place relatively quickly and stays in the flow rate adjusting tank 2 for a predetermined time. In the meantime, most of the combined chlorine is consumed. Thereafter, the solubilized sludge diluted with waste water is sent to the aeration tank 3 and again treated with activated sludge, and the solubilized sludge is decomposed into water and carbon dioxide. Thereafter, the same treatment is performed to reduce the volume of sludge.

  Even in the sludge solubilizer B according to the present embodiment, the sludge cannot be completely solubilized. That is, the sludge that has become difficult to be decomposed gradually may be accumulated in the sedimentation tank 4. Therefore, a predetermined amount of the sludge drawn out from the settling tank 4 is periodically sent to the surplus sludge storage tank 8 provided separately, dehydrated as described above, and transferred to the disposal site.

  The wastewater treatment apparatus according to the present embodiment can be variously modified. For example, although the biomaster reaction tank according to the embodiment is configured with two tanks, it can be implemented with one tank or with three or more tanks. Moreover, when the flow rate adjusting tank is not provided, the sludge solubilized in the biomaster reaction tanks 17 and 18 can be returned to the conventionally known raw water pit. In the raw water pit, the residence time of the wastewater is not long like the flow control tank, so the reaction time between the residual chlorine in the solubilized sludge and the organic matter in the wastewater is short, but it is diluted with a large amount of wastewater. There is no difference with the flow rate adjustment tank, and free chlorine is reliably consumed in the residual chlorine, and the concentration of combined chlorine is diluted and lowered, so that safety can be ensured without affecting the aeration tank. . In addition, the biomaster liquid is described as being produced by a biomaster liquid production apparatus, but it is also possible to prepare a biomaster liquid produced in advance in a dedicated storage tank and inject it. it can. In this case, however, the biomaster solution is highly active and easily decomposed, so care must be taken, such as low temperature control and shortening the storage days.

The following experiment was conducted to investigate the appropriate reaction time between sludge and biomaster liquid.
Take 1L of returned sludge with pH 8.1 in two containers, put 100mL of biomaster liquid with chlorine concentration of 3000mg / L and pH 6.5 on one side, 200mL on the other, filter the mixture, and leave the filtrate. Chlorine concentration was measured. The results are shown in Table 1.

According to Table 1, it can be seen that in any container, most hypochlorous acid was consumed by the reaction in 5 minutes, and the residual chlorine concentration was about 10 mg / L. However, it can be seen that it takes 15 minutes or more for the remaining 10 mg / L of residual chlorine to be sufficiently consumed, and about 30 to 60 minutes for substantially all of it to be consumed. Residual chlorine consists of free chlorine and bound chlorine, but free chlorine with a very high bactericidal effect reacts and is consumed quickly as is well known in the art, but bonded chlorine with a relatively low bactericidal effect is consumed. take time. Conventionally, it has been explained that such bound chlorine reacts with ammonia to form chloroamines, but it can be seen that it is more complicated when viewed from experimental results. Although chloroamines have high solubility and take time to consume, it is unlikely that they will remain at a low concentration for 30 minutes or more, but residual chlorine is detected even after 60 minutes in the experiment. Unlike the conventionally known bonded chlorine, it is highly possible that the chlorine is not easily decomposed, for example, directly bonded to sludge. In this experiment, the residual chlorine in the sludge filtrate is measured, so the chlorine directly bound to the sludge remains undecomposed and flows out into the filtrate every time it is measured. It is thought that it was detected. Since such residual chlorine takes time to decompose, the sterilizing power should be considerably low, and even if returned to the aeration tank, there is almost no possibility of affecting the aeration tank.
Therefore, if the reaction is continued for 5 minutes or more and then diluted with wastewater in the flow rate adjustment tank, the residual chlorine concentration will decrease sufficiently, and even if free chlorine remains, it will react quickly with the organic matter in the wastewater. Since it is consumed, it is considered that there is almost no influence on the aeration tank. However, as described above, the reaction that consumes hypochlorous acid is not expected to be simple, and considering the phenomenon that has not been elucidated, the reaction is preferably 15 minutes or more, more preferably 30 minutes or more. It is safe.
It can be seen that the pH is lowered after the reaction. The pH of the sludge was 8.1, but it was changed to acidic by the biomaster liquid. This is because hydrochloric acid was generated by the oxidation reaction. This decrease in pH is preferable because it accelerates the reaction. If a sodium hypochlorite aqueous solution whose pH is not adjusted with hydrochloric acid or the like is used, the pH will be about 9, and the oxidation reaction will be reduced to about 1/30.

The following experiment was conducted to investigate the range of the concentration of sludge that can be treated and the range of the concentration of the biomaster liquid to be injected.
1 L of very high concentration activated sludge having a sludge concentration of about 30000 mg / L was taken in two containers, and the biomaster liquid was injected so as to have different chlorine concentrations. In the container into which the biomaster liquid was injected so that the chlorine concentration of the sludge after injection was 2000 mg / L, the sludge color gradually became white due to the reaction with chlorine, and the sludge was solubilized to some extent. Further, it was estimated that there was almost no chlorine odor after 5 minutes and the residual chlorine concentration was 5 mg / L or less. However, not all sludge was solubilized. On the other hand, in the container into which the biomaster liquid was injected so that the chlorine concentration of the sludge after injection was 3000 mg / L, the sludge was almost whitened and sufficiently solubilized. However, a chlorine odor remained even 5 minutes after the reaction, and the residual chlorine concentration in the sludge filtrate was about 10 mg / L. Since sludge with a higher concentration is relatively difficult to solubilize, it should be subjected to anaerobic decomposition or incineration. From the above, it is considered that the upper limit of the sludge concentration of sludge that is the target of sludge solubilization with hypochlorous acid is 30000 mg / L. Furthermore, considering the residual chlorine concentration, the hypochlorous acid injected into the sludge is considered to have an upper limit of 3000 mg / L of the chloric acid concentration in the sludge after biomaster liquid injection.
As for the lower limit of the chloric acid concentration in the sludge after biomaster liquid injection, the bulking condition should be considered. The bulking state, that is, the state in which activated sludge is difficult to settle in the sedimentation tank frequently occurs in the processing facility and annoys the manager. At this time, the concentration of the precipitated sludge is very low, 2000 to 3000 mg / L. Such a situation could be reproduced in many experiments. According to experiments, it was found that such sludge is solubilized at a chloric acid concentration of 100 mg / L in the sludge after biomaster liquid injection. Therefore, it is considered that the lower limit of the treatable sludge concentration is 2000 mg / L, and the lower limit of the chloric acid concentration in the sludge after biomaster liquid injection is 100 mg / L.

The following experiment was conducted to examine the effect of volume reduction of excess sludge by biomaster liquid injection.
Three 200L aeration tanks / precipitation tanks, tank A, tank B, and tank C are prepared for batch type activated sludge process. First, a total of 70L consisting of a predetermined amount of sedimented sludge and supernatant water is prepared. Sludge was placed in tanks A to C. The following series of treatments were performed once a day for the tanks A to C.
First, the organic waste water 110L is added to the tanks A to C and aerated for 22 hours. Next, after aeration is stopped and precipitation is performed for 90 minutes, 70 L sludge is left in each tank and the supernatant water is drained.
For tank B, the settled sludge out of the remaining sludge is taken into a 10 L reaction vessel, 900 ml of a biomaster solution having a chlorine concentration of 4000 mg / L and pH 6.5 is injected, and stirred for 30 minutes to react. Return to B. Similarly, in the tank C, the settled sludge out of the remaining sludge was taken into a 10 L reaction vessel, and 1800 ml of a biomaster solution having a chlorine concentration of 4000 mg / L and pH 6.5 was injected and stirred for 30 minutes to react. Then return to tank C. For tank A, the biomaster solution is not treated.
For tanks A to C, the above-described series of treatments was repeated for 2 weeks, and the amount of sedimentation sludge increased or decreased during that time, and the amount of suspended solids contained in the extracted supernatant water, that is, the amount of SS, were measured. Totaled for each tank. And the amount of sedimentation sludge was reduced and the amount of increase of sludge was calculated.
Assuming that the increase in sludge in tank A not using the biomaster liquid is 100%, the increase in sludge in tank B was 21%, and the increase in sludge in tank C was 11%. Note that the sludge increase amount in the tank B is 17% and the sludge increase amount in the tank C is -12% when only the amount of sedimented sludge remaining in the tank is considered without adding the sludge flowing out as SS. Met. That is, sedimentation sludge decreased in tank C.

The following experiment was conducted to investigate the effect of residual chlorine on the aeration tank.
Using the apparatus used in Example 3, the experiment was performed under substantially the same conditions as in Example 3. However, in the tank B, when 10 L of sludge was solubilized in the reaction vessel with the biomaster solution, the biomaster solution was injected so that the residual chlorine concentration after the reaction for 30 minutes was about 10 to 15 mg / L. . In tank C, when 10 L of sludge was solubilized in the reaction vessel with the biomaster solution, the biomaster solution was injected so that the residual chlorine concentration after the reaction for 30 minutes was about 100 mg / L.
When operated under the above conditions, the sludge in the tank B was slightly whitened but the activity as a sludge was not lost. However, wastewater treatment has not been performed sufficiently. On the other hand, the sludge in the tank C was whitened and almost impossible to operate.
From the above, injecting and reacting a large amount of biomaster liquid and returning it to the aeration tank without adding any treatment in a state where residual chlorine remains at a predetermined concentration or more may affect the aeration tank. I understood.

In order to evaluate the influence of pH on the aeration tank, the following experiment was conducted to examine the change in pH in the tank when the biomaster solution was repeatedly injected every day.
Using the apparatus used in Example 3, the experiment was performed under substantially the same conditions as in Example 3. However, in the tank B, when 10 L of sludge is solubilized with the biomaster liquid in the reaction vessel, the biochemical solution is adjusted so that the residual chlorine concentration in the sludge filtrate after the reaction for 30 minutes is about 10 to 15 mg / L. The master solution was poured, and before returning to the tank B, the residual chlorine was made almost zero with an aqueous sodium thiosulfate solution. In the tank C, when 10 L of sludge is solubilized with the biomaster liquid in the reaction vessel, the biomaster liquid is adjusted so that the residual chlorine concentration in the sludge filtrate after the reaction for 30 minutes is about 100 mg / L. The residual chlorine was made almost zero with an aqueous sodium thiosulfate solution before returning to the tank C.
The above treatment was repeated to measure pH.

  As shown in Table 2, the wastewater to be treated has a relatively low pH, but the pH of each of the treated tanks A to C is almost neutral. Originally, when sludge volume reduction is performed using a biomaster solution, the pH of the aeration tank is slightly reduced by chlorine generated by the oxidation reaction. In fact, in tank B and tank C, when 10 L of sedimented sludge was reacted with the biomaster liquid in the reaction vessel, the average pH after the reaction was 5.3 and 4.3, respectively. The solubilized sludge is slightly acidic in this way, but when looking at the results in Table 2, each tank is almost neutral as described above. It can be seen that the effect of lowering the pH due to the biomaster liquid injection is small and the activated sludge is not damaged. Therefore, the neutralization reaction is considered unnecessary in normal cases. However, neutralization should also be considered when the pH of the wastewater before treatment is low.

In order to investigate how the residual chlorine concentration changes when the solubilized sludge contains a high concentration of residual chlorine and dilutes with waste water containing organic matter after a predetermined time has passed. The following experiment was conducted.
Precipitated sludge was collected, a predetermined amount of biomaster liquid was injected, and stirred for 60 minutes to solubilize. The injection ratio of the biomaster solution was adjusted so that the residual chlorine concentration after solubilization was 30 mg / L. The solubilized sludge having a residual chlorine concentration of 30 mg / L was diluted with food production wastewater having a BOD of about 500 mg / L, that is, wastewater containing organic matter, and stirred for 24 hours by a stirrer or aeration to measure the residual chlorine concentration. Residual chlorine concentration was measured not only in the filtrate but also in the entire sludge. In addition, the aeration in a present Example is for stirring, and is not for carrying out biological treatment. The results are shown in Table 3.

  As shown in Table 3, when the solubilized sludge is diluted with waste water containing organic matter and then stirred and reacted, the concentration of residual chlorine decreases not only due to dilution but also due to reaction. I understand that The residual chlorine concentration consumed by such a reaction is as high as about 70 to 80%.

In an actual plant, the solubilized sludge was returned to the flow rate adjustment tank, and after diluting and staying in the wastewater containing organic matter, an experiment was conducted to investigate how the residual chlorine concentration changes.
The experiment was performed under the conditions shown in FIG. Wastewater containing organic matter flows into the flow rate adjustment tank, is sent to the aeration tank, aerated, and treated with activated sludge. During the experiment, the activated sludge suspended matter in the aeration tank, that is, MLSS is operated in the range of 3000 to 4000 mg / L. Part of the activated sludge-treated sludge is sent to a sedimentation tank, where it is precipitated and extracted as a precipitated sludge having an SS of 6000 to 8000 mg / L. Of the extracted sludge extracted, 15 L of sludge per minute is sent to the biomaster reaction tank, and most of the other sludge is returned to the aeration tank as return sludge. However, a part of the extracted sludge is periodically carried out as excess sludge. The sludge sent to the biomaster reaction tank is injected with the biomaster liquid and is solubilized by stirring for 60 minutes in the biomaster reaction tank, and then sent to the flow rate adjustment tank. The injection amount of the biomaster liquid is adjusted so that the residual chlorine concentration of the solubilized sludge sent to the flow rate adjustment tank is 30 to 50 mg / L. The wastewater containing organic matter flowing into the flow rate adjustment tank is adjusted so that the solubilized sludge sent to the flow rate adjustment tank is diluted 20 times. Moreover, the capacity | capacitance of the flow control tank is determined and designed so that the residence time in a tank may be about 12 hours.
It was operated for 20 days under the above conditions, and the residual chlorine concentration of the solubilized sludge diluted with waste water was measured once a day at the outlet of the flow control tank. In the measurement, the residual chlorine of the whole sludge was measured, not the sludge filtrate. Of the 20 times of measurement, only 2 times a trace amount of residual chlorine of 0.1 mg / L or less was detected, but 18 times no residual chlorine was detected. If it is only diluted with wastewater containing organic matter, the residual chlorine concentration should be 1.5-3 mg / L, but it was found that most of the residual chlorine was decomposed and consumed in the flow control tank. .

  In order to evaluate the cost merit obtained when the wastewater treatment apparatus containing organic matter according to the present embodiment is introduced, a trial calculation was made to compare costs with a conventionally known treatment apparatus. A trial calculation was made assuming that food processing wastewater with a daily amount of 5000 tons was treated. In the conventionally known processing apparatus, sludge is not solubilized with chemicals, etc., and all excess sludge is dehydrated and disposed of as a dehydrated cake. In the processing apparatus according to this embodiment, sludge is solubilized. Then, the volume reduction rate was compared in the examples of 100%, 70%, and 30% as the volume reduction by biological activity treatment in the aeration tank again. The disposal cost of the dehydrated cake was estimated as 15000 yen per ton. Table 4 is a monthly cost comparison table.

From Table 4, when the processing apparatus according to the present embodiment is introduced into a conventionally known processing apparatus, the point at which the total cost is reduced, that is, the breakeven point, is that the sludge volume reduction rate is 30%. I understand. That is, when the sludge volume reduction rate exceeds 30%, the total cost is reduced when the treatment apparatus according to the present embodiment is introduced. In the future, the disposal cost of dewatered cake is expected to increase further as sludge landfill will decrease further, and the break-even point of sludge volume reduction rate will become even smaller, and the processing according to this embodiment The merit of introducing the device is increased.
The feature of the apparatus for treating wastewater containing organic matter according to the present invention is that both initial cost and running cost are low. Since the cost is lower than the conventional sludge volume reduction method using ozone or the like, the breakeven point of the sludge volume reduction rate can be set small.

It is a figure which shows typically the processing apparatus of the organic waste_water | drain which concerns on embodiment of this invention. A graph showing the characteristics or action of hypochlorous acid, where (a) is a graph showing the percentage of available chlorine present in an aqueous solution of sodium hypochlorite at each pH, and (a) is bacteria and persistent It is a figure which shows typically a mode that hypochlorous acid has acted on organic substance. It is a figure explaining the experiment example implemented with the processing apparatus of the organic waste_water | drain which concerns on embodiment of this invention.

Explanation of symbols

A activated sludge treatment equipment B sludge solubilization equipment C biomaster liquid production equipment 1 drainage supply pipe 2 flow control tank 3 aeration tank 4 sedimentation tank
5 Sludge extraction pipe 6 Measuring tank 7 Sludge return pipe 12 Biomaster liquid generator 13 Water supply pipe 14 Sodium hypochlorite tank 15 Hydrochloric acid tank 17 First stage biomaster reaction tank 18 Second stage biomaster reaction tank 21 Connection pipe 24 Stirring blade 26 Sludge supply pipe 27 Biomaster liquid injection pipe 29 Solubilized sludge return pipe 31 Monitoring pH meter

Claims (5)

And aeration step of the activated sludge process the raw wastewater containing organic matter using aeration tank, the sludge generated by the implementation of the aeration step, obtained by mixing dilute hydrochloric acid to sodium hypochlorite solution, A weakly acidic hypochlorous acid aqueous solution having an effective chlorine concentration of 500 to 15000 mg / L and a pH value of 4.0 to 7.0 is added and allowed to stay for a predetermined time while stirring without aeration, solubilizing the sludge. A solubilization treatment step, a dilution step of diluting the sludge solubilized by the implementation of the solubilization treatment step with wastewater to be treated containing organic matter, and a retention step of retaining the solubilized and diluted sludge for a predetermined time. , Comprising an aeration treatment step in which the sludge solubilized, diluted and retained is returned to the aeration tank and treated with activated sludge,
Each process is carried out continuously,
The solubilization treatment step, among the plurality of reaction vessels provided in series, the reaction vessel most upstream side, to supply the sludge Sludge concentration 2000~30000mg / L, of a weak acid of said concentration following chlorite solution is added and stirred so as to chlorine concentration 100 to 3000 / L, or less sequentially sent to the downstream side of the reaction vessel, also agitated in these reaction layers, over a whole as 5 minutes or more Carried out,
The said dilution process and a retention process are implemented over 5 to 24 hours in a flow control tank, The processing method of the waste_water | drain containing the organic substance characterized by the above-mentioned. In the processing method according to claim 1, sludge solubilized by the solubilization treatment step, the part of the sludge obtained by the practice of the aeration step, the remaining sludge return and re-active to the aeration tank A method of treating wastewater containing organic matter that is treated with sludge. The treatment method according to claim 1 or 2, wherein an organic substance is contained, wherein a surfactant comprising an ester or ether mainly composed of coconut oil fatty acid is added to a wastewater to be treated containing the organic substance, and the above steps are performed. Wastewater treatment method. A flow regulation tank containing organic raw wastewater stays, the aeration tank for activated sludge treatment of raw wastewater containing the organic substance flowing from the flow regulation tank, the sludge to be processed by該曝gas tank A settling tank for separating from treated water, and a solubilization reaction apparatus for solubilizing the sludge withdrawn from the settling tank without aeration ,
The solubilization reaction apparatus is composed of a plurality of reaction tanks provided with a stirrer, these reaction tanks are provided in series, and a part of sludge withdrawn from the settling tank in the most upstream reaction tank. And a weakly acidic hypochlorous acid aqueous solution obtained by mixing dilute hydrochloric acid with a sodium hypochlorite aqueous solution, and sludge and hypochlorous acid supplied to the most upstream reaction tank. The chloric acid aqueous solution is configured to be sequentially sent to the downstream reaction tank,
Reactor downstream side of the reaction vessel, which is connected to the flow regulation tank, the sludge which has been solubilized, the residual chlorine concentration by the raw wastewater containing organic matter in the flow rate adjusting tank falls below 3 mg / L Wastewater treatment equipment containing organic matter that is diluted to a dilution rate. 5. The apparatus according to claim 4, wherein the aeration tank is supplied with wastewater to be treated containing an organic substance to which a surfactant composed mainly of an ester or ether mainly composed of coconut oil fatty acid is added. Wastewater treatment equipment containing organic matter.

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