JP2006043575A - Waste liquid treatment device with oil and fat decomposition process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a constitution of a waste liquid treatment device with an oil and fat decomposition process which can continue the decomposition of oil and fat and liquid discharge based on the decomposition without replenishing oil-decomposing bacteria in the waste liquid treatment device with the oil and fat decomposition process. <P>SOLUTION: In the waste liquid treatment device with the oil and fat decomposition process, a flow control tank 1, a measuring tank 3, and an oil and fat decomposition tank 2 are installed. Oil and fat-containing raw liquid is poured into the flow control tank 1. After being mixed with the oil-decomposing bacteria in the flow control tank 1, the raw water is moved to the oil and fat decomposition tank 2 with filter material 5 through the measuring tank 3 at the prescribed flow rate. After decomposing the oil and fat by agitating and mixing the raw water and oil-decomposing bacteria for the prescribed time period in the oil and fat decomposition tank 2, in the waste liquid treatment device with the oil and fat decomposition process performing waste liquid treatment, a part of the waste liquid is returned to the flow control tank 1 (a case where an inflow tank 4 is not installed), or to either or both of the flow control tank 1 and the inflow tank 4 (a case where the inflow tank4 is installed) at a return rate of a numerical value equal to or larger than the reciprocal (1/m) of the average growth rate (m) of the oil-decomposing bacteria until reaching the waste liquid treatment. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  TECHNICAL FIELD The present invention relates to a wastewater treatment apparatus that involves a fat and oil decomposition process for a fat and oil-containing stock solution produced in a food cooking place, a food manufacturing factory, and the like.

  The oil / fat-containing stock solution cannot be drained into public irrigation canals such as sewers in the state of the stock solution as in ordinary domestic wastewater.

  That is, the stock solution is subject to administrative regulations such that the required amount of biochemical oxygen demand (BOD), suspended solids (SS), n-hexane extract, etc. is below the specified quantity. For the first time, drainage is possible only after meeting the regulatory requirements.

  At present, the BOD value and the SS value are 300 to 600 mg / L or less, which is not a very strict regulation, but the n-hexane extract substance has a very strict regulation of 30 mg / L or less. .

  In order to satisfy each of the above standards, a process of hydrolyzing fats and oils with an enzyme of fat-degrading bacteria is essential.

  Usually, in the oil-and-oil decomposition step, in the flow-rate adjusting tank, the stock solution is mixed with the oil-and-oil-decomposing bacteria, and then transferred to the oil-and-oil decomposer tank under a predetermined adjusted flow rate. Has been done.

  However, in the prior art, the stock solution that has been decomposed is directly subjected to a discharge treatment.

  As a result, in the drainage treatment apparatus that involves the oil and fat decomposition step in the prior art, it has been necessary to always replenish the oil-degrading bacteria in the flow rate adjustment tank.

  However, considering that oil-degrading bacteria are sequentially growing in the oil-degrading process, simply draining the stock solution that has been decomposed as in the prior art, the efficiency of the oil-degrading bacteria can be reduced. The use is not considered at all, and there is nothing other than wasteful in terms of economic costs.

Japanese Patent Laid-Open No. 2001-321792. JP 2002-361279 A.

  The present invention relates to a wastewater treatment apparatus with a fat and oil decomposition process, and a wastewater treatment apparatus with a fat and oil decomposition process that can continue the decomposition of the fat and oil and the drainage based on the decomposition without replenishment of the oil and fat decomposing bacteria. It is an issue to provide a configuration.

In order to solve the above problems, the configuration of the present invention is as follows.
(1) Install a flow rate adjustment tank, a measurement tank, and an oil decomposition tank, inject the oil-containing stock solution into the flow adjustment tank, mix the oil-decomposing bacteria in the inflow adjustment tank, and then add the stock solution to the measurement tank. The oil and fat decomposition tank is equipped with a filter medium under a predetermined flow rate, and in the oil and fat decomposition tank, the stock solution and the oil and fat decomposing bacteria are stirred and mixed for a predetermined time, and then drained. In the drainage treatment apparatus with the fat and oil decomposition step for performing the treatment, with a feedback rate by a numerical value equal to or greater than the reciprocal (1 / m) of the average growth rate (m) until the drainage treatment of the fat and oil degrading bacteria, A drainage treatment apparatus with a fat and oil decomposition process based on returning a part of the drainage to the flow rate adjustment tank,
(2) An inflow tank, a flow rate adjustment tank, a metering tank, and an oil decomposition tank are installed, and an oil-containing stock solution is poured into the flow tank, and after removing coarse solids, the inflow adjustment tank is transferred to the inflow adjustment tank. After mixing the oil-degrading bacteria in the above, the stock solution is transferred to a fat-and-oil decomposition tank equipped with a filter medium at a predetermined flow rate through the measuring tank, In an effluent treatment apparatus with an oil and fat decomposition process for decomposing oil and fat by decomposing and decomposing bacteria, the average growth rate (m) of the oil and fat decomposing bacteria until the effluent treatment is achieved. Effluent treatment with a fat and oil decomposition process based on returning a part of the effluent to one or both of the inflow tank and the flow rate adjustment tank with a feedback rate with a numerical value greater than the reciprocal (1 / m) apparatus,
Consists of.

  In the present invention having the above basic configuration, the oil decomposing step and the subsequent draining step can be continued without supplementing the oil decomposing bacteria.

  As is apparent from the section of the means for solving the problem, the present invention installs the configuration (1) and the inflow tank 4 that do not require the inflow tank 4 to remove coarse solids. However, in any of the above configurations (1) and (2), a part of the drainage is used in the final drainage treatment step. Returning to the flow rate adjustment tank, the effect can be exhibited by the feedback.

Hereinafter, description will be made with reference to FIGS. 1A and 1B showing a typical embodiment of the present invention.
1A corresponds to the configuration of (1), and FIG. 1B corresponds to the configuration of (2).

  As shown in FIGS. 1 (a) and 1 (b), in a drainage treatment apparatus that involves an oil and fat decomposition step, after mixing the oil and fat-containing stock solution and the oil and fat-degrading bacteria and adjusting the flow rate, The basic configuration is a flow rate adjustment tank 1 that is transferred to the next step through the measuring tank 3 and an oil and fat decomposition tank 2 that decomposes the oil and fat in the transferred stock solution.

  The flow rate adjusting tank 1 is usually equipped with a stirrer to realize the mixing, but in order to efficiently dissolve oxygen in the stock solution, the region where the stirrer is stirred is used. It is preferable to perform aeration by supplying air through an air supply pipe 8 as shown in FIG.

  The full-fat decomposing process by the oil-degrading bacteria is realized in the oil-decomposing tank 2.

  In the oil and fat decomposition tank 2, the filter medium 5 is installed, and while supporting oil-decomposing bacteria and increasing the contact area between the oil-decomposing bacteria and the fats and oils, it contributes to the improvement of the oil-decomposing function.

As shown in FIG. 1B, the configuration (2) is provided with an inflow tank 4 for containing a fat-containing stock solution discarded by a food cooking place, a food manufacturing factory, and the like, and a coarseness in the stock solution. The solid solution is transferred to the flow rate adjustment tank 1 after removing the solid matter.
However, since the inflow tank 4 is not necessarily installed depending on the level of the water level, as shown in FIG. 1A according to the configuration of (1), there is a configuration in which the inflow tank 4 is not installed. Will be able to.
In addition, in the inflow tank 4, it is also possible to perform aeration by performing mechanical agitation and further supplying air in order to prevent the oil and fat components from being cured and adhering to the wall. .

  In order to perform sufficient decomposition in the fat and oil decomposition tank 2, it is essential that the oil and fat decomposing bacteria are stored in the fat and oil decomposition tank 2 for a time necessary for performing the decomposition function at a predetermined concentration or more. To do.

  Usually, when draining in units of one day, a residence of 8 hours or more is often required.

  In order to explain the basic principle of the constitutions (1) and (2), in the process in which the oil-degrading bacteria reach the oil-degrading tank 2 from the flow rate adjusting tank 1 to the oil-decomposing tank 2, the oil-decomposing bacteria drainage treatment When the average growth rate up to is m and the concentration of the oil-degrading bacteria at the stage of draining in the oil-degrading tank 2 is a, in the configuration of (1), The average concentration of the oil-degrading bacteria initially present is about a / m. In the configuration of (2), the average concentration of the oil-degrading bacteria initially present in the flow rate adjusting tank 1 (return to the flow rate adjusting tank 1 only? Or when returning to both the flow control tank 1 and the inflow tank 4), or the average concentration of the oil-degrading bacteria initially present in the inflow tank 4 (when returning only to the inflow tank 4) is about a / m. It is.

  On the other hand, when the return rate when the fat-containing stock solution is drained from the fat / oil decomposition tank 2 is r, and other oil-degrading bacteria are not supplemented, it is formed in the flow rate adjusting tank 1 based on the feedback. The concentration of the oil-degrading bacterium is a · r, and in the configuration of (2), the average concentration of the oil-degrading bacterium initially present in the flow rate adjustment tank 1 (returned to the flow rate adjustment tank 1 only or the flow rate adjustment In the case of returning to both the tank 1 and the inflow tank 4), or the average concentration of the oil-degrading bacteria initially present in the inflow tank 4 (in the case of returning only to the inflow tank 4) is about a · r.

  In order to continue the decomposition in one decomposition tank by the returned oil-degrading bacteria without supplementing the oil-degrading bacteria, and to continue drainage, the concentration of the returned oil-degrading bacteria depends on the growth rate m, It must be at least a / m, which is the concentration necessary to finally reach the necessary concentration a.

  That is, by a · r ≧ a / m, eventually r ≧ 1 / m, that is, the return ratio is at least the reciprocal (1 / m) or more of the average growth rate (m) of the oil-degrading bacteria. It is essential.

  As the oil-degrading bacterium used in the present invention, any of the anaerobic, aerobic, and micro-aerobic characteristics that are intermediate between the two can be adopted. Is set to 8 hours or more, the growth rate m is 2 to 5 in most cases. Therefore, the feedback ratio r is 1/5 to 1/2, that is, 20% to 50%. It is often set with.

  As described above, in the present invention, the oil and fat is returned to the flow rate adjusting tank 1 by returning the drainage liquid with a return rate equal to or greater than the reciprocal (1 / m) of the average growth rate (m) of the oil-degrading bacteria. Without replenishing the decomposing bacteria, the oil and fat decomposition step in the oil and fat decomposition tank 2 and the subsequent drainage step can be continued.

  The average growth rate (m) is detected in advance by collecting experimental data on changes in the concentration of the decomposing bacteria in the process of transferring the oil decomposing bacteria to the oil decomposing tank 2 together with the oil-containing stock solution. can do.

  In order to make the concentration of the oil-degrading bacteria constant in the oil-degrading tank 2, the feedback rate (r) is preferably set to be approximately equal to the reciprocal (1 / m) of the average growth rate (m).

  On the contrary, when the feedback rate (r) is set larger than the reciprocal (1 / m), the concentration of the oil-degrading bacteria in the oil-decomposing tank 2 becomes larger than necessary and exceeds the appropriate amount. It is preferable to temporarily stop the feedback and restart the feedback again when the concentration in the fat and oil decomposition tank 2 reaches the required concentration a.

  Therefore, in the initial stage of continuing the fat and oil decomposition, it is essential to supply the oil-degrading bacteria to the flow rate adjusting tank 1.

  Reflecting such a situation, in the embodiment shown in FIGS. 1 (a) and 1 (b), the oil-degrading bacteria tank 7 is provided, and in order to realize oil decomposition in the initial stage, Oil and fat-degrading bacteria are supplied.

However, at the initial stage, it is possible to manually supply the oil-degrading bacteria to the flow rate adjusting tank 1 without providing the oil-degrading bacteria tank 7, so the installation of the oil-degrading bacteria tank 7 is not necessarily required. It is not an indispensable requirement.
However, considering that the manual labor is complicated and that it is very convenient to supply the oil-degrading bacteria from the oil-decomposing tank 2 when an accident occurs during the oil-decomposing process. For example, as described above, it is extremely preferable to provide the oil-degrading bacteria tank 7.

  In the following, description will be made in accordance with examples.

  In the embodiment, as shown in FIG. 2, oil is contained in the oil and fat decomposition tank 2 by supplying air through the air supply pipe 8 and ejecting air from the air ejection device 9 in the oil and fat decomposition tank 2. It is characterized by aeration of the stock solution.

  As described above, when aeration is performed in the fat and oil decomposition tank 2, the oil and fat decomposing bacteria are activated, and the fat and oil decomposition function in the fat and oil decomposition tank 2 can be remarkably improved.

  By adopting the configuration according to the embodiment, the amount of dissolved oxygen is set to 3 mg / L or more by sufficient aeration, and in the fat and oil decomposition tank 2 provided with the filter medium 5 by the nonwoven fabric, a sufficient aeration state is obtained, and the fat-containing stock solution When the ATB oil-degrading bacterium was employed as the oil-degrading bacterium, the following results could be obtained.

  As is clear from the test results, it is found that a remarkable decomposition function is exhibited in the examples.

  INDUSTRIAL APPLICABILITY The present invention can be used in the field of treatment of effluent containing fats and oils such as food cooking places and food manufacturing factories.

It is a block-like sectional view showing the basic principle of the present invention, (a) corresponds to the configuration of (1), and (b) corresponds to the configuration of (2). In addition, P shows the pump for moving a fat-and-oil containing undiluted | stock solution. It is sectional drawing which shows the condition of the fats-and-oils decomposition tank in an Example. In addition, the arrow by a black line has shown the flow direction based on the stirring mechanism by air ventilation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Flow control tank 2 Oil and fat decomposition tank 3 Measuring tank 4 Inflow tank 5 Filter medium 6 Return pipe 7 Oil and fat decomposition bacteria tank 8 Air supply pipe 9 Air ejection apparatus 10 Bubble

Claims (7)

  Install a flow rate adjustment tank, a measurement tank, and a fat and oil decomposition tank, inject the oil-containing stock solution into the flow rate adjustment tank, mix the oil-degrading bacteria in the inflow adjustment tank, and then pass the stock solution through the measurement tank. The oil and fat decomposition tank equipped with a filter medium under a predetermined flow rate is transferred to the oil and fat decomposition tank, and after the oil and fat are decomposed by stirring and mixing the stock solution and the oil and fat decomposing bacteria for a predetermined time, the drainage treatment is performed. In a wastewater treatment apparatus with an oil and fat decomposition step, the wastewater is discharged with a feedback rate with a numerical value equal to or greater than the reciprocal (1 / m) of the average growth rate (m) up to the drainage treatment of the fat and oil degrading bacteria. A drainage treatment apparatus with a fat and oil decomposition process based on returning a part of the oil to the flow rate adjustment tank.   An inflow tank, a flow rate adjustment tank, a metering tank, and a fat and oil decomposition tank are installed, and an oil-containing stock solution is injected into the flow rate tank to remove coarse solids and then transferred to the inflow adjustment tank. After mixing the degrading bacteria, the stock solution is transferred to an oil and fat decomposition tank equipped with a filter medium under a predetermined flow rate via a measuring tank, and the stock solution and the oil and fat decomposing bacteria and In a drainage treatment apparatus with a fat and oil decomposition step for decomposing fats and oils by stirring and mixing, the reciprocal number (1) of the average growth rate (m) up to the drainage treatment of fat and oil degrading bacteria / M) A drainage treatment apparatus with an oil and fat decomposition process based on returning a part of the drainage liquid to one or both of the inflow tank and the flow rate adjustment tank with a feedback rate with a numerical value equal to or higher than the above.   The drainage treatment apparatus with an oil and fat decomposition process according to claim 1 and 2, wherein a rate of return is 20 to 50% by weight of the drainage.   The drainage treatment with an oil and fat decomposition process according to claim 1 and 2, wherein an oil and fat decomposing bacteria tank for supplying the oil and fat decomposing bacteria is installed in the flow adjustment tank at the start of operation. apparatus.   The wastewater treatment apparatus with an oil and fat decomposition process according to claim 1 and 2, wherein air is supplied to the oil and fat decomposition tank by an air supply pipe to aerate the oil and fat-containing stock solution.   3. A drainage treatment method using a drainage treatment apparatus with a fat and oil decomposition process according to claim 1, wherein the return rate is approximately equal to the reciprocal (1 / m) of the average growth rate (m). .   When the concentration of the oil-degrading bacteria in the oil-degrading tank exceeds the concentration that is originally necessary and appropriate for decomposition, the feedback is stopped until the concentration returns to the concentration. A drainage treatment method using a drainage treatment apparatus with a fat and oil decomposition process.

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