JP6403504B2 - Method and apparatus for treating organic wastewater containing fats and oils - Google Patents

Description

  The present invention relates to a method and apparatus for treating organic wastewater, and more particularly to a method and apparatus for treating organic wastewater containing fats and oils accompanied by biological treatment.

  Emissions from oil and fat manufacturing factories, side dish factories, fried confectionery factories, cake manufacturing factories, livestock processing factories such as hams and sausages, dairy manufacturing factories, marine products processing factories, kitchens such as canteens and restaurants, and food-related establishments Organic wastewater containing vegetable oils and animal fats generally has a higher fat content than BOD (biological oxygen demand) content. Therefore, the activity of activated sludge is hindered in the biological treatment of organic wastewater at the biological treatment facility, and this biological treatment becomes difficult. That is, the fats and oils in the waste water are adsorbed around the activated sludge floc to form a film, oxygen cannot reach inside the activated sludge floc, and oxygen supply to the activated sludge is insufficient, and the activity of the activated sludge is reduced. In this situation, in addition to the BOD of the organic waste water, the effect of removing fats and oils is significantly reduced.

  In addition, the form of fats and oils in organic wastewater is the form of oil balls combined with solidified state, emulsified state (emulsion state), dispersed state (colloidal), hardness components (for example, calcium and magnesium), etc. due to temperature decrease. In general, biological treatment is difficult in the form of fats and oils other than the emulsified state.

  When wastewater containing a large amount of fats and oils is biologically treated, floating materials such as foaming in the biologically treated water tank and scum derived from actinomycetes are generated, which hinders stable facility operation. Therefore, when biologically treating organic wastewater containing a large amount of animal and vegetable fats and oils, it is necessary to reduce the amount of fats and oils before the wastewater flows into the biologically treated water tank.

  The oil and fat concentration in the wastewater is measured as a hexane extract (JISK0102: 2013 Factory Wastewater Test Method 24.2). In addition, a hexane extract substance means the substance extracted to the hexane side by mixing fat-and-oils containing waste water with the organic solvent hexane.

  When discharging sewerage, it is necessary to significantly reduce the concentration of hexane extractables based on the discharge water standard. In addition, oil and fat countermeasures are required to protect sewer pipes and prevent oil balls. Also for this purpose, pretreatment of organic wastewater containing fats and oils is important.

  As a method for preventing the inhibition of biological treatment by fats and oils, a method of removing fats and oils in advance by pressurized levitation in the previous stage of biological treatment is common.

  In addition to flotation under pressure, the fats and oils in the organic wastewater are converted into enzyme agents mainly composed of fat-degrading enzymes (lipases) and microorganisms having lipase activity such as Bacillus sp. And Ralstonia sp. A method for decomposing oils and fats with a microbial preparation containing microorganisms) has been proposed.

  Patent Document 1 discloses a method of biological treatment after adding fat and oil-degrading enzyme lipase to fat and oil-containing wastewater to hydrolyze the fat and oil in the wastewater. In Patent Document 2, organic wastewater containing hardly-degradable lipids is mixed with sludge containing lipid-assimilating yeast, so that lipids are directly degraded by yeast without any additional treatment for lipids. An organic wastewater treatment apparatus that enables this is disclosed.

  Patent Document 3 discloses an apparatus for treating fat-containing wastewater, in which an oil-degrading bacterium is carried on a fluid carrier, and the carrier carrying the oil-degrading bacterium is supplied from the oil-degrading bacteria culture tank to the oil-degrading pretreatment tank or biological treatment tank. Has been.

  In Patent Literature 4, fat-decomposing bacteria are cultivated, and the culture solution is supplied to an oil-degrading tank to decompose fats and oils in the fat-containing wastewater. A processing device is disclosed.

JP-A-5-146798 JP 2000-246284 A Japanese Patent Laid-Open No. 11-188376 JP 2001-129580 A

  However, although the conventional pressure floatation is an excellent method for removing fats and oils, the removed fat and oil-containing solidified product is not easily concentrated or dehydrated, and therefore easily perishes and easily generates malodor. Therefore, the fat-and-oil-containing solidified product after removal has poor handleability and workability, and the disposal cost increases.

  In addition, according to the addition of the lipase of Patent Document 1, the added lipase flows out together with the treated water. Therefore, it is necessary to always add the lipase in order to continue the hydrolysis of fats and oils in the stable waste water. High cost.

  According to the yeast treatment of Patent Document 2, in order to perform the yeast treatment, it is necessary to remove solids having a size that is not suitable for yeast treatment from the organic waste water. A separate treatment of the solid content is required.

  In the processing apparatuses of Patent Document 3 and Patent Document 4, the fat and oil in the fat-containing wastewater is decomposed by the pre-cultured fat-and-oil decomposing bacteria prior to the biological treatment (aerobic treatment) of the fat and oil-containing wastewater. Since the part and other parts are in contact with the oleolytic bacteria in a mixed state, the contact efficiency between the oleophilic part and the oleolytic bacteria is low, and the processing efficiency is low. Therefore, in order to reduce the fat and oil content in the fat and oil-containing wastewater, a long time treatment is required.

  This invention is made | formed in view of the said subject, The objective provides the processing method of the organic waste_water | drain which can decompose | disassemble and remove the fats and oils in the organic waste_water | drain containing fats and oils, and its apparatus. There is to do.

Invention of the organic wastewater containing the fats and oils of Claim 1 for achieving the said objective is the solidification process which solidifies and screen-separates the fats and oils in fats and oils containing organic wastewater with an organic polymer flocculant. A pre-reaction step in which an enzyme that promotes fat and oil degradation and / or a microorganism that secretes the enzyme is mixed with at least a part of the fat-containing solidified product solidified in the solidifying step to obtain a reaction product by the enzymatic reaction; the reaction from the previous reaction step, the decomposed oil and fat of the fat-containing solidified product in produced by solidifying step, the oil decomposition step to obtain a fat splitting was the oil degradation products, oils and fats containing hardened by the curing step and biological treatment by mixing the remaining liquid after removal of the object, and having a biological treatment process to obtain a treated water and excess sludge, the.

  According to this configuration, since the fat-containing solidified product solidified in the solidification step and then taken out is provided for the fat-decomposing step, the fat-and-oil decomposition is selectively performed only on the fat-containing solidified product containing a high concentration of fats and oils. The treatment is performed, and the oil and fat in the organic waste water can be efficiently decomposed and removed. Then, by mixing the oil-and-fat decomposed product with reduced oil and fat with the residual liquid after taking out the oil-containing solidified product, the concentration of the oil and fat remaining in the oil-and-fat decomposed product in the mixed liquid is diluted by the residual liquid and further biological treatment is performed. It is easy and it is efficient because biological treatment is performed on both at the same time.

In addition, since an enzyme that promotes fat and oil decomposition and / or a microorganism that secretes this enzyme is added in the pre-reaction step, when activated sludge is added to the pre-reaction step, the amount exceeds the treatment capacity of the activated sludge. The fat-and-oil-containing solidified product is decomposed by the enzyme, and the fat and oil decomposition by activated sludge is promoted. After that, the amount of the enzyme that promotes the fat and oil decomposition to be supplied to the fat and oil decomposition step is reduced by supplying the reaction liquid containing the enzyme that promotes the fat and oil decomposition obtained in the previous reaction step to the fat and oil decomposition step. Can do. Therefore, the oil and fat in the organic waste water can be further efficiently decomposed and removed.

The invention of the processing apparatus for organic wastewater containing fats and oils according to claim 2 is a flocculant mixing tank in which the fat-containing organic wastewater is mixed with an organic polymer flocculant and the fats and oils in the organic wastewater are solidified. A screen separation device that is provided downstream of the flocculant mixing tank or the flocculant mixing tank and takes out the oil-containing solidified product obtained by solidifying the fat from the flocculant mixing tank, and at least one of the oil-containing solidified product. A part is mixed with an enzyme that promotes oil and fat decomposition and / or a microorganism that secretes the enzyme, and becomes a place for the enzyme reaction, and a pre-reaction tank for obtaining a reaction product after the reaction, and a reaction from the pre-reaction tank The oil-and-oil decomposition tank which decomposes | disassembles the fats and oils contained in the said fat-and-oils solidified product and obtains a fat-and-oil decomposed product, the oil-and-fat decomposed material from the said oil-and-fat decomposer, Is mixed A biological treatment tank for biologically treating to obtain treated water and surplus sludge, and a return means for returning surplus sludge from the biological treatment tank to the pre-reaction tank and the oil decomposition tank. .

According to this configuration, the fats and oils in the organic waste water are solidified in the flocculant mixing tank, and at least a part of the fat-containing solidified product taken out after that is separated from the fat and oil-degrading enzyme in the previous reaction tank different from the fat and oil decomposition tank. The reaction product after this reaction and the fat-and-oil-containing solidified product that has not been used in this reaction are subjected to the oil and fat decomposition in the oil and fat decomposition tank. Therefore, not only the fat and oil decomposition treatment is selectively performed only on the high-concentration fat and oil-containing solidified product, but also the efficiency of the oil and fat decomposition treatment is greatly improved by the reaction product. Therefore, the fats and oils in the organic waste water are efficiently decomposed and removed.

The invention according to claim 3, in the processing apparatus of organic waste water containing oil according to claim 2, the addition amount of the reaction product of the from the previous reaction vessel to the oil decomposition tank, in the fat decomposition tank It is characterized by being 5% wt / wt or more with respect to the amount of the oil-containing solidified product charged.

Invention of Claim 4 is the processing apparatus of the organic waste_water | drain containing fats and oils of Claim 2 or 3 , The fat-containing solidified material transferred to the said pre-reaction tank is taken out by the said screen separator. It is characterized by being 5 to 20% wt / wt with respect to the total amount of oil-containing solidified product.

  According to the present invention, the oil and fat in the organic waste water can be efficiently decomposed and removed, so that the organic waste water containing the oil and fat can be quickly treated in the system, and the solid-liquid separated fat and oil can be removed. You are freed from the trouble of disposing it separately.

It is the schematic which shows the whole structure of the processing apparatus of the organic waste_water | drain which concerns on embodiment of this invention. It is a flowchart explaining the flow of the processing method using the processing apparatus of the organic waste_water | drain which concerns on embodiment of this invention. It is the principal part schematic of the processing apparatus of the organic waste_water | drain in which a continuous biological treatment is performed. It is a figure for demonstrating the modification of the solidified material taking-out apparatus of this Embodiment.

  Next, embodiments of the present invention will be described in detail with reference to the drawings. A method and apparatus for treating organic wastewater containing fats and oils will be described with reference to FIGS. FIG. 1 is a schematic diagram showing the overall configuration of an organic wastewater treatment apparatus 10, and FIG. 2 is a flowchart for explaining the flow of a treatment method using the organic wastewater treatment apparatus 10.

  As shown in FIG. 1, the organic wastewater treatment apparatus 10 includes a mixing tank (first flocculant mixing tank) 12 into which an organic wastewater 100 containing oil and fat discharged from an oil refinery / oil manufacturing factory or the like flows. Have. The mixing tank (first flocculant mixing tank) 12 stirs and mixes the charging path into which the organic polymer flocculant 13 (13a) is charged and the organic waste water 100 with the organic polymer flocculant 13 (13a). A stirrer is provided.

  Upstream of the mixing tank (first flocculant mixing tank) 12, the organic waste water 100 discharged from the oil refinery / oil manufacturing plant or the like is stored and allowed to flow into the mixing tank (first flocculant mixing tank) 12. An adjustment tank (1) 16 for adjusting the amount of the organic waste water 100 is optionally provided.

  The organic waste water 100 that has passed through the mixing tank (first flocculant mixing tank) 12 is received downstream of the mixing tank (first flocculant mixing tank) 12 and mixed with the organic polymer flocculant 13 (13b). A coagulation tank (second coagulant mixing tank) 18 is provided. The aggregating tank (second aggregating agent mixing tank) 18 stirs and mixes the charging path into which the organic polymer aggregating agent 13 (13b) is introduced and the organic waste water 100 with the organic polymer aggregating agent 13 (13b). A stirrer is provided.

  Downstream of the aggregating tank (second aggregating agent mixing tank) 18, a screen separator (solidified substance taking out apparatus) 22 for taking out the solidified material from the effluent from the aggregating tank (second aggregating agent mixing tank) 18. Is provided.

  In this embodiment, the screen separation device (solidified material take-out device) 22 is provided in a substantially rectangular storage part for storing the effluent and an upper part of the storage part, and from one side wall of the storage part to the other side wall. And a wire mesh suspended diagonally. A commercially available device can be used as the screen separation device (solidified material take-out device) 22, and an arbitrary device can be used from the processing amount and the opening of the wire mesh.

  The effluent flowing out from the coagulation tank (second coagulant mixing tank) 18 is solid-liquid separated into a solidified material deposited on the wire mesh and a liquid that has passed through the wire mesh by a screen separation device (solidified material take-out device) 22. The The solidified material deposited on the wire mesh is sent to an oil / fat solubilization tank (oil / fat decomposition tank) 26 via a path 24. In the present embodiment, the mesh opening of the wire mesh is 2 mm, but is not limited to this size, and the size of the mesh is appropriately changed depending on the size of the particles of the oil-containing solid material 46 described later. It is possible.

  Downstream of the screen separator 22, an oil / fat solubilization tank (oil / fat decomposition tank) 26 to which the solidified material deposited on the wire mesh is transferred via the path 24 and an oil / fat to which the solidified substance is similarly transferred via the path 28. A culture apparatus (pre-reaction tank) 30 separate from the solubilization tank 26 is provided. Further, an adjustment tank (2) 29 in which the liquid that has passed through the wire mesh is transferred via the path 23 is provided downstream of the screen separation device 22.

  The culture apparatus (pre-reaction tank) 30 has a jacket part that covers the culture apparatus (pre-reaction tank) 30 from the outside, and the inside of the culture apparatus (pre-reaction tank) 30 is formed by a heat transfer medium that circulates in the jacket part. Temperature control is possible. Further, the culture apparatus (pre-reaction tank) 30 has a stirrer capable of stirring the substance in the culture apparatus (pre-reaction tank) 30 and a charging path into which the oil / fat decomposer 15 described later is charged. The substance in the culture apparatus (pre-reaction tank) 30 is transferred to the downstream fat / oil solubilization tank 26 via the path 34.

  The fat-and-oil solubilization tank (oil-and-fat decomposition tank) 26 includes a charging path into which the oil-and-fat decomposing agent 15 is charged and a stirrer that can stir the internal substances. The substance in the oil / solubilization tank 26 is transferred to the downstream adjustment tank (2) 29 via the path 36 and mixed with the separation liquid (residual liquid) that has passed through the above-described wire mesh. A biological treatment tank 32 to which the mixed liquid is transferred via a path 37 is provided downstream of the adjustment tank (2) 29.

  A diffuser is disposed in the lower part of the biological treatment tank 32. A path 38 for discharging treated water 110 after biological treatment, which will be described later, is connected to the biological treatment tank 32, and the lower part is generated after biological treatment. A path 40 for discharging excess sludge 120 is connected. In addition, the path | route 40 has branched to the path | route 42 and the path | route 44 which return the excess sludge 120 to the culture apparatus (pre-reaction tank) 30 and the fat-and-oil solubilization tank 26, respectively.

  In FIG. 1, the biological treatment tank 32 has been described with reference to a biological treatment tank used for batch biological treatment, but the biological treatment itself may be performed continuously. FIG. 3 is a schematic diagram of a main part of an organic wastewater treatment apparatus in which continuous biological treatment is performed, that is, a configuration used for biological treatment. As shown in the figure, a sedimentation tank 33 is provided downstream of the biological treatment tank 32. Therefore, the path 38 for discharging the treated water 110 after biological treatment is connected to the sedimentation tank 33, and the path 40 for discharging surplus sludge 120 generated after biological treatment is connected to the lower part of the sedimentation tank 33. Yes. In addition, the path | route 40 branches into the path | route 42, the path | route 44, and the path | route 45 which return the excess sludge 120 to the culture apparatus (pre-reaction tank) 30, the fat-and-oil solubilization tank 26, and the biological treatment tank 32, respectively.

  Next, an organic wastewater treatment method using the organic wastewater treatment apparatus 10 having the above configuration will be described below.

[Solidification step and organic polymer flocculant to be used]
First, the solidification step S101 (see FIG. 2) will be described. In the first place, the organic waste water 100 is not limited to those in which fats and oils are dissolved, but there are solidified fat and oil-containing particles that are not dissolved but are dispersed. In the present specification, these oils and fats and oil-containing particles are separated into solid and liquid by an oil and fat-containing solidified product take-out device such as a screen separation device 22 (see FIG. 1) and a pressurized flotation separation device 60 (see FIG. 4) described later. The term “solidification” refers to solidification of a possible size.

  As shown in FIG. 1, the organic waste water 100 is introduced into the mixing tank (first flocculant mixing tank) 12 through the adjustment tank (1) 16, and the organic polymer coagulation is performed on the organic waste water 100. Agent 13 is mixed.

  The organic polymer flocculant 13 used may be any as long as it flocculates the oil and fat in the organic waste water 100, but in the present embodiment, it is the cationic organic polymer flocculant 13a. Ebagulose LDC-100, Ebagulose LDC-201, Ebagulose LDC-208, and Ebagulose CS-374 (manufactured by Mizuing Co., Ltd.) can be used.

  The addition amount of the cationic organic polymer flocculant 13a is 1% wt / wt or more per SS of the organic waste water 100, preferably in the range of 1 to 10% wt / wt, more preferably 5 to 10%. It is the range of wt / wt. SS is a suspended substance and is one of the indicators of turbidity of water. Particles contained in water are filtered through glass fiber filter paper or MF membrane filter paper having a pore size of 1 μm, and the dry weight of the particles. (Mg / L).

  After the organic waste water 100 mixed with the cationic organic polymer flocculant 13a is stirred by a stirrer, the entire amount of the liquid mixture is transferred to a flocculant tank (second flocculant mixing tank) 18.

  The organic polymer flocculant 13 is further added to the liquid mixture transferred to the flocculant tank (second flocculant mixing tank) 18 and further stirred and mixed by a stirrer.

  The organic polymer flocculant 13 to be added may be any one as long as it can agglomerate the fats and oils in the organic waste water 100. In the present embodiment, the organic polymer flocculant 13b is an anionic organic polymer flocculant 13b. Ebagulose A-151, Ebagulose A-151C, Ebagulose A-161, and Ebagulose A-202C (manufactured by Mizuing Co., Ltd.) can be used.

  The addition amount of the anionic organic polymer flocculant 13b is 0.8% wt / wt or more per SS of the organic waste water 100, preferably in the range of 1 to 5% wt / wt, more preferably 1 ~ 3% wt / wt.

  The type and amount of the organic polymer flocculant 13 are merely examples, and the concentration of a hexane extractant in a later-described separation liquid (residual liquid) 48 after the generation of floc 46 is 50 mg / L or less (preferably, 30 mg / L or less), and any kind and amount may be used.

  When stirring and mixing, the fats and oils in the organic waste water 100 aggregate and solidify, and a strong flock in the liquid, that is, the fat and oil-containing solidified product 46 is generated.

[Oil and fat-containing solidified product removal step (screen filtration)]
Next, the oil-containing solidified product removal step S102 (see FIG. 2) for extracting the oil-containing solidified product 46 from the liquid containing the oil-containing solidified product 46 will be described. As shown in FIG. 1, the liquid containing the oil-containing solidified product 46 is discharged from the coagulating tank (second coagulant mixing tank) 18 to the outside of the coagulating tank 18, and the screen separation device (solidified product taking out device) 22. To be separated into solid and liquid. That is, the fat-and-oil-containing solidified product 46 is deposited on the wire mesh, and the liquid that has passed through the wire mesh is stored in the storage section, and becomes a separated liquid (residual liquid) 48 that remains after the oil-and-fat-containing solidified material 46 is taken out after solid-liquid separation. At least a part of the fat and oil-containing solidified product 46 on the wire net is transferred to another culture apparatus (pre-reaction tank) 30 via the path 28. The remaining part of the oil-containing solidified product 46 is transferred to the oil / solubilization tank 26 via the path 24. The fat / oil-containing solidified product 46 transferred to the culture apparatus (pre-reaction tank) 30 is preferably 5 to 20% wt / wt with respect to the total amount of the fat / oil-containing solidified material 46 deposited on the wire mesh of the screen separation device 22. .

[Pre-reaction process]
Next, the pre-reaction step S103 (see FIG. 2) performed before the oil and fat decomposition step S104 will be described. As shown in FIG. 1, in this step, the fat / oil decomposing agent 15 and activated sludge used in biological treatment are added to the culture apparatus (pre-reaction tank) 30 in which the fat / oil-containing solidified product 46 is charged, and the mixture is stirred with a stirrer. While the fat and oil decomposing agent 15 and the activated sludge are reacted with the fat and oil-containing solidified product 46.

  The activated sludge may be any activated sludge used in biological treatment. For example, activated sludge in the biological treatment tank 32 can be used. The amount of activated sludge added is 10% wt / wt or more in dry weight with respect to the oil-containing solidified product 46 put into the culture apparatus (pre-reaction tank) 30.

  Examples of the fat and oil degrading agent 15 include enzymes that promote fat and oil decomposition and microorganisms that secrete this enzyme. An enzyme that promotes oil degradation may be used alone, a microorganism that secretes this enzyme may be used alone, or both may be used in combination.

  For example, as the oil and fat decomposing agent 15, commercially available user sour 120 and user sour 400 (both manufactured by Mizuing Co., Ltd.) can be exemplified. The use sour 120 is a preparation mainly composed of an oil-degrading enzyme, and the use sour 400 is a preparation mainly composed of an oil-degrading enzyme and a microorganism secreting the oil-degrading enzyme. When adding the sour 120, the addition amount should just be 0.1% wt / wt or more with respect to the amount of hexane extraction substances of the fat-containing solidified substance 46, Preferably it is 0.3% or more.

  When using the sour 400, the addition amount may be 0.1% wt / wt or more, preferably 0.3% or more with respect to the amount of the hexane extracted substance in the floc 46.

  The reaction temperature is adjusted by a heat transfer medium flowing through the jacket portion 30a, and is, for example, 30 ° C. However, the reaction temperature can be appropriately adjusted to a temperature suitable for enzyme reaction or a temperature suitable for microorganism growth.

  The reaction time may be 3 days or more, preferably in the range of 3 days to 10 days, and more preferably in the range of 5 days to 10 days.

  After the reaction, the oil / fat-containing solidified product 46 is solubilized by an enzymatic reaction, and this reaction liquid (reactant) 50 is transferred to the oil / fat solubilization tank 26 via the path 34.

  Note that the pre-reaction step S104 is not essential. When the pre-reaction step is not performed, the total amount of the oil-containing solidified product 46 separated on the wire mesh of the screen separation device (solidified product removing device) 22 is supplied to the oil-and-fat decomposition step S104.

[Oil and fat decomposition process]
Next, the oil and fat decomposition step S104 (see FIG. 2) will be described. As shown in FIG. 1, the oil-and-fat solubilization tank (oil-and-fat decomposition tank) 26 is charged with the part of the oil-and-fat-containing solidified product 46 remaining on the wire mesh without being subjected to the pre-reaction step S103 in the oil-and-fat-containing solidified product taking-out step To do. When the pre-reaction step S103 is performed, the reaction liquid (reactant) 50 obtained in the pre-reaction step S103 is further added to the oil / solubilization tank 26.

  The amount of the reaction liquid 50 to be added may be 5% wt / wt or more, preferably 10% wt / wt or more, with respect to the amount of the oil-containing solidified product 46 put into the oil / solubilization tank 26. More preferably, it is 20% wt / wt or more.

  The period during which the fat and oil decomposition step S104 is carried out can be set as a measure that the concentration of the hexane extract substance in the fat and oil decomposition product 52 at the end of the step is 6,000 mg / L or less. Moreover, the temperature which performs fats-and-oils decomposition can be suitably set to the temperature of the range in which the fat-and-oil decomposition reaction rate is fully maintained.

  When the reaction solution 50 is not added, the oil / fat decomposer 15 is added. The same fat and oil decomposing agent 15 as the oil and fat decomposing agent 15 described in the previous reaction step S103 can be used as the oil and fat decomposing agent 15. Furthermore, it is possible to add both the oil-and-fat decomposer 15 and the reaction liquid 50 together.

After completion of the oil and fat decomposition step S104, the oil and fat-containing solidified product 46 becomes a solubilized oil and fat decomposed product 52. Therefore, the oil and fat decomposition step S104 can also be referred to as an oil and fat solubilization step.
The obtained oil / fat decomposition product 52 is transferred to the adjustment tank (2) 29 via the path 36 and mixed with the separated liquid (residual liquid) 48 obtained in the oil / fat-containing solidified product taking-out step S102. To do. The mixing ratio of the two is set so that the concentration of the hexane extractant in the mixed solution 54 is 1,000 mg / L or less (preferably 700 mg / L or less). The mixed liquid 54 is transferred to the biological treatment tank 32 via the path 37.

[Biological treatment process]
Next, a case where the biological treatment process S105 (see FIG. 2) is performed in a batch manner will be described as an example. As shown in FIG. 1, the biological treatment is performed by adding the mixed liquid 54 and activated sludge to the biological treatment tank 32. Specifically, the conditioned treatment for adapting the microorganisms in the activated sludge to the mixed liquid 54. It is performed by the period and the steady process after the acclimatization.

-Acclimatization process Activated sludge is added to the biological treatment tank 32 to which the mixed solution 54 has been added so that the MLSS is 1 to 5 g / L (MLSS is SS expressed in g / L). Thereafter, aeration from the diffuser is performed. The mixed liquid 54 is added to the biological treatment tank 32 in a batch manner so that a predetermined BOD sludge load is obtained. In addition, nitrogen (N) and phosphorus (P) are added as nutrients in amounts such that BOD: N: P = 100: 5: 1 in the mass ratio of N and P, respectively, in the acclimation treatment and the steady treatment. Is done. Urea or ammonium salt is used as the nitrogen source, and phosphoric acid or phosphate is used as the phosphorus source. Thereafter, when the BOD removal rate during the acclimatization process exceeds 90%, it is determined that the acclimatization is completed. The BOD removal rate is calculated as follows.

  BOD removal rate (%) = {BOD (mg / L) of inflow water to biological treatment tank (mixed liquid 54) −BOD (mg / L) of treated water 110} / Inflow water (mixed liquid 54) BOD (mg / L) * 100

Steady treatment As shown in FIG. 1, the activated sludge after completion of the adaptation is left in the biological treatment tank 32 so that the MLSS becomes 1 to 5 g / L, and the mixed solution 54 is batch-type so as to have a predetermined BOD sludge load. Is added to the biological treatment tank 32 and aerated from the diffuser. The aeration period is, for example, 10 hours to 12 hours, and then takes a settling time for settling activated sludge. The settling time is, for example, 1 hour.

  After the sedimentation of the activated sludge, the treated water 110 after the biological treatment is discharged to a public water area (for example, a sewer) through the path 38. In the biological treatment tank 32, the volume of the activated sludge increases due to the increase of microorganisms in the activated sludge due to the biological treatment, and as a result, the excess sludge 120 is generated. Discharged through. Thereafter, a new mixed solution 54 is added to the biological treatment tank 32, and the next biological treatment is performed.

  In the case where the biological treatment is performed continuously, the mixed solution 54 is continuously supplied to the biological treatment tank 32 without taking a settling time as in the batch biological treatment. The treated water 110 after treatment flows downstream. Such treated water 110 contains activated sludge and is not preferably discharged as it is.

  Therefore, when the biological treatment is performed in a continuous manner, as shown in FIG. 3, the activated sludge and treated water 110 that have flowed out of the biological treatment tank 32 are discharged from the biological treatment tank 32 in the sedimentation tank 33 provided downstream of the biological treatment tank 32. The unseparated suspension is allowed to settle. Thereafter, the supernatant after settling in the settling tank 33 is discharged as treated water 110 via a path 38. The activated sludge accumulated in the sedimentation tank 33 is discharged as surplus sludge 120 via the path 40 and is returned to the biological treatment tank 32 via the path 45.

  Therefore, according to the method and apparatus 10 for treating organic wastewater according to the present embodiment, the oil-containing solidified product 46 solidified in the solidification step S101 and then taken out is provided to the oil decomposition step S104. The oil / fat decomposition treatment is selectively performed only on the oil / fat-containing solidified product 46 containing the component at a high concentration, and the oil / fat in the organic waste water 100 can be efficiently decomposed and removed. And the fat and oil decomposition product 52 which fats and oils reduced and solubilized is mixed with the separated liquid (residual liquid) 48 after taking out the fat and oil-containing solidified product, whereby the concentration of fat and oil remaining in the oil and fat decomposition product 52 in the mixed solution 54 Is diluted with the separation liquid (residual liquid) 48 to facilitate further biological treatment, and the biological treatment is simultaneously performed on both, which is efficient.

  Furthermore, when the pre-reaction step S103 is carried out, an enzyme that promotes oil and fat decomposition and / or a microorganism that secretes this enzyme and the activated sludge are added in the pre-reaction step S103. The fat and oil-containing solidified product 46 exceeding the capacity is decomposed by the enzyme, and the oil and fat decomposition by the activated sludge is promoted.

  After that, the reaction liquid (reactant) 50 containing the enzyme that promotes fat and oil decomposition obtained in the pre-reaction step S103 is supplied to the fat and oil decomposition step S104, thereby accelerating the fat and oil decomposition to be supplied to the fat and oil decomposition step S104 The amount of enzyme to be reduced can be reduced. That is, it is economical because the amount of the enzyme that promotes the oil and fat decomposition that is continuously supplied to the oil and fat decomposition tank 26 and / or the microorganism that secretes the enzyme can be reduced.

  In addition, surplus sludge 120 generated after the biological treatment step S105 can be supplied to the culture apparatus (pre-reaction tank) 30 and the oil / fat solubilization tank (oil / fat decomposition tank) 26 via the path 42 and the path 44, respectively. . In this case, the addition of the excess sludge 120 after the biological treatment step S105 further promotes the decomposition and removal of the fat and oil in the pre-reaction step S103 and / or the fat and oil decomposition step S104, and as a result, the amount of the excess sludge 120 discharged after the biological treatment Can be reduced.

  In the present embodiment, the solidified product takeout device is exemplified as the screen separation device (solidified product takeout device 22) provided downstream of the coagulation tank (second coagulant mixing tank) 18, but the present invention is not limited thereto. However, various modifications are possible. Below, the modified example of the solidified substance taking-out apparatus is demonstrated based on FIG.

  4, elements similar to those in the embodiment shown in FIGS. 1 and 2 described above are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 4, in this modification, instead of the screen separation device 22, a pressure levitation treatment device (solidified material removal device) 60 is provided downstream of the coagulation tank (second coagulant mixing tank) 18. It has been. The pressure levitation treatment device 60 is provided in a pressure levitation tank that receives the liquid in the coagulation tank (second coagulant mixing tank) 18 together with the aggregates, and a pressurized water 130 provided on a side wall near the bottom of the pressure levitation tank. This embodiment is provided in that it includes a pressurized water inflow portion for inflow, and further includes a floss scraper that scrapes off the floss (oil-containing solidified product) 46 that has floated on the liquid surface of the coagulation tank (second coagulant mixing tank) 18. It differs from the screen separation device 22 of the form.

[Oil and fat-containing solidified product removal step (pressurization flotation treatment)]
The oil-and-fat-containing solidified product removal step S102 according to this modification will be described. As shown in FIG. 4, the liquid containing the fat-and-oil-containing solidified product 46 generated by the solidification step S <b> 101 (see FIG. 2) is transferred to the pressurized flotation tank of the pressurized flotation separation device 60. And pressurized water is made to flow in from this pressurized water outflow part in this pressurized levitation tank. Then, a large number of bubbles are generated from the pressurized water decompressed in the pressurized levitation tank, and floats on the water surface while adhering the particles of the oil / fat-containing solidified product 46. Further, the floss (oil-containing solidified product) 46 floating on the water surface is scraped off by a floss scraper, and the oil-solubilizing tank (oil-decomposing tank) 26 and the culture apparatus (pre-reaction tank) via the paths 24 and 28. ) 30 respectively.

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning of invention. In the present embodiment, the organic polymer flocculant uses two types of cationic organic polymer flocculant and anionic organic polymer flocculant in combination, but any one of them may be used. . Again, any organic polymer flocculant may be used as long as it has a function of agglomerating and solidifying fats and oils in organic waste water.

  Moreover, in this Embodiment, although the two flocculant mixing tanks are provided, only one may be sufficient and three or more may be sufficient.

  Hereinafter, the present invention will be described with reference to examples.

1-1. Solidification of organic wastewater and extraction of oil-containing solidified products (screen filtration)
Take 1 liter of the lunch box manufacturing wastewater (hereinafter referred to as organic wastewater 100) shown in Table 1 in a 1 liter beaker, and the organic wastewater 100 contains the cationic organic polymer flocculant 13a shown in Table 2 in the same table. Each was added in the amount shown in FIG. The rapid stirring conditions were a commercially available jar tester with a stirring speed of 120 revolutions per minute. Next, an anionic organic polymer flocculant 13b (Ebagulose A-151, product of Watering Co., Ltd.) was added in an amount of 1% wt / wt per SS of the organic wastewater 100, and the mixture was gently stirred for 3 minutes. The slow stirring conditions were a commercial jar tester with a stirring speed of 50 revolutions per minute.

  The whole amount of the organic waste water 100 containing the oil-containing solidified product 46 produced by this aggregation is passed through a substantially rectangular wire mesh fence (length 5 cm × width 5 cm × height 3 cm) with a screen opening of 2 mm (screen filtration). The produced fat / oil-containing solidified product 46 was taken out.

  When the anionic organic polymer flocculant 13b (Ebagulose A-151, a product of Mizu ing Co., Ltd.) is added in an amount of 1% wt / wt per SS of the organic waste water 100, the size of the product oil-containing solidified product 46 is increased. Was 2 mm to 5 mm, and the time required for filtration of the whole amount with a wire mesh cage having an opening of 2 mm was 7 seconds.

  When Ebagulose A-151 is added in an amount of 0.8% wt / wt per SS of the organic waste water 100, the size of the produced strong flock, that is, the fat-containing solidified product 46 becomes 1 mm to 3 mm. The outflow of the oil-containing solidified product 46 from was observed. When the addition rate of Ebagulose A-151 was increased to 1.5% wt / wt per SS of the organic wastewater 100, the size of the product oil-containing solidified product 46 was increased to 3 mm to 6 mm. The total time required for filtration was 20 seconds.

  The water content of the produced oil / fat containing solidified product 46 subjected to screen filtration and the water quality of the separated liquid (residual liquid) 48 after the oil / fat containing solidified product 46 was taken out were measured. The results are shown in Table 2. As shown in Table 2, Ebagulose LDC-201 (product of water ing Co., Ltd.) is added as cationic organic polymer flocculant 13a at 5% wt / wt per SS of organic waste water 100, and anionic organic polymer flocculant is added. When Ebagulose A-151 is added at 1% wt / wt per SS of the organic waste water 100 as the agent 13b, the amount of the hexane extractable substance in the separated liquid (residual liquid) 48 after taking out the oil-containing solidified product 46 is reduced. From the viewpoint of the moisture content of the fat-and-oil-containing solidified product 46, it was determined that it was the most preferable addition condition.

  The moisture content is a value obtained by multiplying the ratio of the weight loss and the sample weight when the sample is dried at 105 to 110 ° C. for 2 hours by 100 (the sewage test method, volume 1, 2012 edition 5 sludge / gas test Chapter 1 General sludge test Section 6 (Depending on evaporation residue and water content).

1-2. Solidification of organic waste water and extraction of oil-containing solidified products (pressure flotation treatment)
After using the organic waste water 100 of “1-1.” To produce a fat-containing solidified product under the same conditions as “1-1.”, A pressure levitation treatment test was performed with 10% to 30% of pressurized water. . Pressurized water was prepared by blowing air into tap water. The pressurized water was added to the agglomerated organic wastewater 100, and air was attached to the oil-containing solidified product to float, and the generated floss (oil-containing solidified product) 46 was taken out.

  The pressurized water addition rate is expressed as% vw / vw in the amount of pressurized water / the amount of organic wastewater 100 * 100.

  The water quality of the separated liquid (residual liquid) 48 after the pressure flotation treatment and the moisture content of the generated floss (oil-containing solids) 46 were measured. The results are shown in Table 3.

  In the section where the amount of pressurized water added was 20%, the floss separation rate and water quality in any cationic organic polymer flocculant 13a were good.

2. Pre-reaction Cationic organic polymer flocculant 13a (Ebagulose LDC201) is added to organic wastewater 100 of “1-1.” In an amount of 3% wt / wt per SS of organic wastewater 100, and anionic organic high The molecular flocculant 13b (Ebagulose A-151) was added in an amount of 1% wt / wt per SS of the organic wastewater 100 to produce a fat-containing solidified product 46. The oil / fat-containing solidified product 46 was taken out from the oil-and-fat-containing solidified product 46 by the same screen filtration as “1-1.”, And at the same time, a separation liquid (residual liquid) 48 after taking out the oil / fat containing solidified product was obtained. The obtained oil-and-fat-containing solidified product 46 had a water content of 90.0% (that is, a solid content of 10% (100,000 mg / L)), and the hexane extract was 50,000 mg / L.

  1 kg of oil and fat-containing solidified product taken out to an open type culture device (culture device (pre-reaction tank) 30) equipped with a hot water jacket that can be heated from the outside with a capacity of 1 liter and a stirrer that can stir the inside of the device (hexane extract material) 43 g), and while maintaining the temperature at 30 ° C., the fat and oil decomposing agent Usour 300 (Watering Corporation product), Usour 120 (Watering Corporation product), Usour 400 (Watering Corporation product) were added, Changes in the properties of the liquid inside the culture apparatus 30 were investigated.

  Table 4 shows the properties of the liquid in the culture apparatus (culture apparatus (pre-reaction tank) 30) after 5 days, and Table 5 shows the results of measuring the concentration of the hexane extractant in the liquid in the culture apparatus.

3. Decomposition of fats and oils Cationic organic polymer flocculant 13a (Ebagulose LDC201) is added to organic wastewater 100 of “1-1.” At 3% wt / wt per SS of organic wastewater 100, and anionic organic polymer flocculant 13b (Ebagulose A-151) was added at 1% wt / wt per SS of the organic waste water 100 to produce a fat-containing solidified product 46. The oil-and-fat-containing solidified product 46 is changed to 1-1. In the same manner as in the above, a liquid-separated separated liquid (residual liquid) 48 was obtained after the oil-containing solids 46 were taken out at the same time as the liquid was filtered.

  The fat and oil-containing solidified product 46 produced in “1-1.” Has a water content of 90.3% (that is, a solid content of 9.7% (97,000 mg / L), and the hexane extractable substance content is 50 per SS. % (SS is 97.0 g / L, and the amount of hexane extracted substance is 97 × 0.5 = 48.5 g. Here, SS and fats and oils are separate components).

  1 kg of fat and oil-containing solidified product extracted in “1-1.” (Hexane extraction) in an open type oil and fat solubilization tank (oil and fat decomposition tank) 26 equipped with a stirrer capable of stirring the inside of the apparatus with a capacity of 1 liter (water depth 15 cm) 49 g / L) of the substance, and the reaction solution obtained at 15 ° C. to 25 ° C. at the oil and fat decomposing agent Usour 120 (Watering Corporation product), Usour 400 (Watering Corporation product) and “2. (Reaction product 50) was added, and the fats and oils were decomposed in the oil and fat solubilization tank 26.

  Table 6 shows the results of the fat and oil decomposition of the extracted fat-containing solidified product 46. The reaction liquid A is a reaction liquid with a 0.3% addition rate of USOUR 120 obtained in “2. Pre-reaction”, and the reaction liquid has a reaction day of 5 days. It is a reaction solution for 5 days. The amount of reaction liquid (% wt / wt) of “2. Pre-reaction” is shown as a ratio with respect to 1 kg of the oil / fat-containing solidified product taken out in “1-1.”.

  By adding the reaction liquid A in an amount of 10% wt / wt with respect to the weight of the product-containing fat-containing solidified product 46, the amount of hexane extract after 3 days was reduced to 6,000 mg / L (see number 11 in Table 6). ). The water quality of the classification after decomposition of fats and oils (No. 11 in Table 6) was pH 6.6, SS 50,000 mg / L, and BOD 80,000 mg / L.

4). Biological treatment 4-1. Adjustment of liquid mixture used for biological treatment Table 7 shows the separation liquid (residual liquid) 48 after the oil-and-fat-containing solidified product is taken out in “1-1.” And the classification after oil-and-oil decomposition obtained in “3. The water quality of (No. 11 in Table 6) is shown.

  A mixed liquid 54 in which the separation liquid (residual liquid) 48 shown in Table 7 and the division after fats and oils decomposition (Table 6, No. 11) were mixed at 10: 1 was prepared and subjected to biological treatment.

4-2. Biological treatment conditions Biological treatment is performed by an acclimatization process in which microorganisms in the activated sludge are adapted to the mixed solution 54 and a steady process in which the biological treatment is performed with the adapted activated sludge. Table 8 shows biological treatment conditions for the habituation treatment and the steady treatment. In this embodiment, the biological treatment is performed in a batch system, but the biological treatment conditions shown in Table 8 are also applied to the continuous system.

4-3. Acclimatization and biological treatment As shown in FIG. 1, activated sludge (seed sludge, MLSS 3.0 g / L) in a sewage treatment facility is placed in a biological treatment tank 32 (capacity 5 liters, water depth 30 cm) provided with a diffuser at the bottom of the water tank. ), The mixed solution 54 in Table 7 and the nutrient in Table 8 were added, and the BOD was removed by aeration from the diffuser part continuously for about 22 hours. Thereafter, aeration was stopped, the sludge was settled, and the supernatant liquid after 1 hour was collected as the conditioned treatment water, and the excess sludge 120 was drawn out so that the conditioned sludge concentration was 3.0 g / L (as MLSS). Thereafter, the mixed solution 54 shown in Table 7 was added so as to obtain a predetermined BOD sludge load, and aeration was resumed.

  Acclimatization is performed at a BOD sludge load of 0.1 kg / kg / day, acclimatization of seed sludge is performed for about 2 weeks, and the BOD removal rate in the latter half of the acclimatization treatment period is 90% to 95%, and the acclimatization is completed. It was judged. Table 9 shows the results of biological treatment of activated sludge after acclimatization with a BOD sludge load of 0.2 to 0.4 (kg / kg · day).

4-4. Biological treatment (comparative example)
The conditions shown in Table 8 of “4-2. Conditions for biological treatment” using the activated sludge after the adaptation of “4-3. Adaptation and biological treatment” for the organic waste water 100 of “1-1.” The biological treatment was performed.

  Table 10 shows the results. The organic wastewater 100 contains a large amount of hexane extract, which impedes biological treatment. When the BOD sludge load exceeds 0.2 kg / kg · day, scum generation and abnormal foaming increase in the biological treatment tank. It was difficult to continue processing.

4-5. Fat and oil decomposition (oil and fat-containing solidified product + excess sludge)
After the steps from “4-1. Preparation of mixed solution for biological treatment” to “4-3. Adaptation and biological treatment”, that is, the biological treatment, The mixture of the excess surplus sludge 120 (Table 9, BOD sludge load 0.2 kg / kg) mixed at a weight ratio of 1: 1 was subjected to fat and oil decomposition under the conditions shown in “3. It was.

  Table 11 shows the properties of the above mixture, and Table 12 shows the results of fat and oil decomposition of the mixture.

  By mixing the excess sludge 120 which is activated sludge, the effect of removing the hexane extractant was higher than in Table 6 of “3.

10 Organic wastewater treatment equipment 12 Mixing tank (first flocculant mixing tank)
DESCRIPTION OF SYMBOLS 13 Organic polymer flocculant 13a Cationic organic polymer flocculant 13b Anionic organic polymer flocculant 15 Fat and oil decomposition agent (enzyme which accelerates | stimulates fat decomposition and microorganism which secretes this enzyme)
18 Coagulation tank (second coagulant mixing tank)
22 Screen separation device (solidified material removal device)
26 Oil and fat solubilization tank (oil and fat decomposition tank)
30 Incubator (Pre-reactor)
32 biological treatment tank 46 Oil-containing solidified product, generated floss (oil-containing solidified product)
48 Separation liquid (residual liquid)
50 reaction liquid (reactant)
52 Decomposed oil and fat 54 Mixture (mixture)
60 Pressurized flotation treatment device (solidified product removal device)
100 Organic waste water 110 Treated water 120 Excess sludge

Claims (4)

A solidification step of solidifying and screen-separating the fats and oils in the organic wastewater containing fats with an organic polymer flocculant;
A pre-reaction step in which an enzyme that promotes fat and oil degradation and / or a microorganism that secretes the enzyme is mixed with at least a part of the fat-containing solidified product solidified in the solidifying step to obtain a reaction product by the enzymatic reaction;
By the reaction product from the previous reaction step, the oil and fat in the oil and fat-containing solidified product produced by the solidification step is decomposed, and an oil and fat decomposition step for obtaining an oil and fat decomposed product,
A biological treatment process in which the fat and oil decomposition product is mixed with a residual liquid after taking out the fat and oil-containing solidified product in the solidification step to obtain a treated water and surplus sludge;
The processing method of the organic waste water containing fats and oils characterized by having. An oil-containing organic wastewater is mixed with an organic polymer flocculant, and a flocculant mixing tank in which the oil and fat in the organic wastewater is solidified,
A screen separation device that is provided downstream of the flocculant mixing tank or the flocculant mixing tank and takes out the oil-containing solidified product obtained by solidifying the fat from the flocculant mixing tank;
A pre-reaction tank in which at least a part of the fat-containing solidified product is mixed with an enzyme that promotes the decomposition of fats and oils and / or a microorganism that secretes the enzyme, and serves as a site for the enzyme reaction; ,
With the reactant from the previous reaction tank, an oil and fat decomposition tank that decomposes the fat and oil contained in the fat and oil-containing solidified product to obtain an oil and fat decomposition product;
A biological treatment tank in which the fat and oil decomposition product from the fat and oil decomposition tank and the residual liquid after taking out the fat and oil-containing solidified product by the screen separator are mixed and biologically treated to obtain treated water and excess sludge;
Returning means for returning surplus sludge from the biological treatment tank to the pre-reaction tank and the fat and oil decomposition tank;
An organic wastewater treatment apparatus containing fats and oils. The amount of the reactant added from the pre-reaction tank to the fat / oil decomposition tank is 5% wt / wt or more with respect to the amount of the oil / fat-containing solidified substance charged into the fat / oil decomposition tank. The processing apparatus of the organic waste water containing the fats and oils of 2 . Fat-containing solidified product to be transferred before said reaction vessel, according to claim 2 or 3, characterized in that said a 5 to 20% wt / wt relative to oil-containing solidified product the total amount to be taken out by the screen apparatus Organic wastewater treatment equipment containing fats and oils.

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