JP4979614B2 - Disposer wastewater treatment method and treatment equipment - Google Patents

Description

  The present invention relates to a method and an apparatus for efficiently and simply treating wastewater containing soot that has been pulverized by a disposer (hereinafter sometimes simply referred to as “disposer wastewater”).

  Disposers are attracting great interest in recent years because they can be attached to a sink and pulverized together with kitchen wastewater to discharge them, and can easily and sanitize garbage. On the other hand, since the disposer wastewater contains a lot of organic matter derived from dredging, there is a problem that the treatment load becomes excessive in ordinary sewage treatment and the purification treatment cannot catch up. Therefore, in recent years, a method of discharging the disposer wastewater to the sewer after having been subjected to the aerobic biological treatment in advance has become widespread, but this method has a drawback of consuming a large amount of power in the aerobic microorganism treatment. . In addition, as a treatment method for disposer wastewater, a method of treating by methane fermentation has also been proposed, but since methane fermentation alone still cannot reduce the organic matter concentration to the sewer discharge standard, further aerobic microorganism treatment after methane fermentation There is an inconvenience that it must also be provided.

Conventionally, various technologies have been proposed as wastewater treatment methods (see Patent Document 1, etc.), but a technology suitable for treating disposer wastewater efficiently and simply has not been developed yet. It is.
JP 2005-224692 A

  An object of this invention is to provide the processing method and processing apparatus of the disposer waste_water | drain which can process a disposer waste_water | drain efficiently and simply.

  The present inventor has intensively studied to solve the above problems, and (1) a step of solid-liquid separation of the disposer wastewater, (2) a solid fraction separated from the disposer wastewater is subjected to a methane fermentation treatment. Step, (3) the step of solubilizing the obtained methane fermentation sludge, and (4) mixing the obtained solubilized product with the liquid fraction separated from the disposer wastewater, By implementing the process of methane fermentation by the sewage sludge bed method, it is possible to purify the disposer wastewater efficiently and simply and reduce the organic matter concentration to the extent that the sewer can be discharged. I found it. The present invention has been completed by further studies based on such knowledge.

That is, this invention is the processing method hung up below:
Item 1. A method for treating wastewater containing soot that has been pulverized by a disposer, including the following steps:
A first step of solid-liquid separation of waste water containing soot that has been pulverized by a disposer into a solid fraction and a liquid fraction;
A second step of subjecting the solid fraction obtained in the first step to a methane fermentation treatment,
The third step of solubilizing the methane fermentation sludge obtained in the second step and the liquid fraction obtained in the first step and the solubilized product obtained in the third step are mixed, and the upward flow The 4th process used for methane fermentation processing by an anaerobic sludge bed method.
Item 2. Item 2. The treatment method according to Item 1, wherein a part of the solubilized product obtained in the third step is again subjected to the methane fermentation treatment in the second step.
Item 3. Item 2. The treatment method according to Item 1, wherein the solubilization treatment in the third step is a heat treatment under a temperature condition of 70 ° C or higher.
Item 4. In the fourth step, the liquid fraction obtained in the first step is mixed with 1 part by weight of the solubilized product obtained in the third step at a mixing ratio of 50 parts by weight or more, and this is an anaerobic upflow The processing method of claim | item 1 which is a process used for the methane fermentation process by a sludge bed method.

Furthermore, the present invention is a processing apparatus listed below:
Item 5. A solid-liquid separation device that separates wastewater containing soot that has been pulverized by a disposer into a solid fraction and a liquid fraction;
A methane fermentation tank for performing methane fermentation on the solid fraction separated by the solid-liquid separator,
A solubilization tank for solubilizing methane fermentation sludge discharged from the methane fermentation tank;
A mixing tank for mixing the liquid fraction separated by the solid-liquid separator and the solubilized product discharged from the solubilization tank;
An upward flow methane fermentation treatment tank that performs methane fermentation by the upward flow anaerobic sludge bed method for the mixed liquid discharged from the mixing tank,
An apparatus for treating wastewater containing soot that has been pulverized by a disposer.

  According to the treatment method and the treatment apparatus of the present invention, the disposer waste water can be purified efficiently and simply, and the organic matter concentration can be reduced to such an extent that the sewer can be discharged. In general, the organic matter remaining after anaerobic treatment such as methane fermentation is hardly decomposed even when the same anaerobic treatment is performed again. However, according to the treatment method and treatment apparatus of the present invention, 2 By performing the solubilization process as an intermediate process of two methane fermentation processes, it is possible to significantly reduce the remaining amount of organic matter.

I. Treatment Method The present invention is a method for purifying waste water containing waste that has been pulverized by a disposer (disposer waste water), a step of separating the disposer waste water into a solid and liquid (first step), and a solid separated into solid and liquid The step of subjecting the fraction to methane fermentation (second step), the step of solubilizing methane fermentation sludge (third step), and the liquid fraction separated from solid and liquid and the solubilized treated product upflow anaerobic sludge It includes a step (fourth step) of methane fermentation treatment by a floor method. Hereinafter, the processing method of the present invention will be described in detail for each step.

First Step In the treatment method of the present invention, first, the disposer drainage is subjected to a solid-liquid separation step (first step). As the solid-liquid separation method, a method conventionally used for solid-liquid separation of waste water can be used, and examples thereof include screen separation, precipitation separation, membrane separation, and centrifugal separation.

  The solid fraction thus separated into solid and liquid is subjected to a methane fermentation treatment (second step) described later, and the liquid fraction further separated into solid and liquid is mixed with a solubilized treatment product described later to counter-current. The methane fermentation process (4th process) by an anaerobic sludge bed method is used. The solid fraction used in the second step may be in the state separated by the above-described solid-liquid separation method, and the liquid may not be completely removed and may be in a liquid state.

Second Step Next, the solid fraction obtained in the first step is subjected to a methane fermentation treatment (second step). That is, this 2nd process is implemented by performing methane fermentation with respect to the solid fraction obtained at the said 1st process in anaerobic atmosphere. By the methane fermentation treatment in the second step, among the organic matter in the solid fraction obtained in the first step, the organic matter that can be used by the methane fermentation fungus is decomposed into methane and carbon dioxide.

  In the methane fermentation process performed in the second step, the preparation / maintenance of the anaerobic atmosphere can be performed using carbon dioxide, nitrogen, argon, hydrogen, natural gas, methane, city gas, and the like. Moreover, you may use oxygen removal agents, such as sodium sulfide, as needed.

  Moreover, the temperature conditions of the methane fermentation in the second step can be appropriately set from a wide temperature range depending on the type of methane fermentation bacteria to be used, and are not particularly limited, but generally about 20 to 60 ° C. For example, a so-called intermediate temperature of about 35 ° C. or a so-called high temperature of about 55 ° C. may be used.

  The form of methane fermentation in the second step is not particularly limited as long as the solid fraction obtained in the first step can be methane-fermented. For example, a batch type, a continuous type, a fixed bed type, etc. Illustrated.

  The processing time of methane fermentation in the second step varies depending on the amount of the solid fraction to be processed, the type of methane fermentation bacteria used, the fermentation temperature, the fermentation form, etc., and cannot be defined uniformly. 10 to 30 days, preferably 10 to 20 days, and more preferably 10 to 14 days.

  Thus, methane fermentation sludge is obtained by performing a methane fermentation process. The obtained methane fermentation sludge is used for the solubilization process (3rd process) mentioned later.

Third Step Next, the methane fermentation sludge obtained in the second step is solubilized (third step). By the solubilization treatment in the third step, the organic matter remaining in the methane fermentation sludge obtained in the second step (that is, the organic matter not decomposed by methane fermentation) is reduced in molecular weight.

  The solubilization treatment in the third step is not particularly limited as long as the organic matter remaining in the methane fermentation sludge can be reduced in molecular weight, and a solubilization treatment conventionally employed in waste treatment can be used. Specific examples of the solubilization treatment in the third step include heat treatment, alkali treatment, acid treatment, decomposition treatment with microorganisms other than methane fermentation bacteria, ultrasonic treatment, pressure treatment, ozone treatment, and the like. For these solubilization treatments, treatment conditions that are usually used in waste treatment may be adopted, and examples of specific conditions thereof will be exemplified below.

  As specific conditions for the heat treatment, for example, 60 ° C. or more, preferably about 60 to 90 ° C., more preferably about 65 to 80 ° C., and particularly preferably 70 ° C. with respect to the methane fermentation sludge obtained in the second step. Examples include a method of treating under a temperature condition of about -80 ° C., for example, for 1 to 96 hours, preferably 12 to 72 hours, and more preferably 24 to 48 hours. In this heat treatment, heavy oil, city gas, electric power, etc. may be used as an energy source for maintaining the heating temperature. However, using the methane gas generated in the second step and the fourth step described later, heat and It is desirable to use exhaust heat obtained by cogeneration means (gas engine, fuel cell, etc.) for obtaining electric power. During the heat treatment, by appropriately adjusting the heating temperature, the heating time, the return amount from the solubilization tank to the methane fermentation tank, etc., microorganisms with high solid solubilizing power, for example, Thermotoga bacteria are dominant. By increasing the efficiency, it is possible to obtain higher disposer wastewater treatment efficiency. The amount of Thermotoga bacteria can be measured by the Real Time PCR method.

  Specific conditions for the alkali treatment are, for example, about 9 days or less, preferably about 1 hour under the conditions of pH 9 to 14, preferably 10 to 12, with respect to the methane fermentation sludge obtained in the second step. The method of processing is mentioned.

  As the acid treatment, there is a method of treating the methane fermentation sludge obtained in the second step, for example, under conditions of pH 1 to 5, preferably 2 to 4 days or less, preferably about 1 hour. Can be mentioned.

  Among these solubilization treatments, heat treatment is preferable from the viewpoint of simplicity and increasing the solubilization rate (low molecularization rate) of the remaining organic matter.

  Thus, by performing the solubilization treatment, a solubilized treatment product is obtained. The solubilized product obtained is subjected to a methane fermentation treatment (fourth step) by the upward flow anaerobic sludge bed method described later together with the liquid obtained in the first step. A part of the solubilized product obtained may be subjected again to the second step, whereby the remaining amount of organic matter can be further reduced.

Fourth Step Next, the liquid fraction obtained in the first step and the solubilized product obtained in the third step are mixed and subjected to a methane fermentation treatment by an upflow anaerobic sludge bed method (first step). 4 steps). By the methane fermentation treatment in the fourth step, the organic matter contained in the liquid fraction obtained in the first step and the organic matter in the solubilized treatment product obtained in the third step are converted into methane and carbon dioxide by methane fermentation. It is possible to reduce the concentration of organic matter in the wastewater that is decomposed into water and finally discharged to such an extent that sewerage can be discharged.

  In this 4th process, the liquid mixture used for the methane fermentation process by an upflow anaerobic sludge bed method is the liquid fraction obtained by the said 1st process, the solubilization processed material obtained by the said 3rd process, However, if necessary, other waste water, tap water, or the like may be mixed. In the fourth step, the mixing ratio of the solubilized product obtained in the third step and the liquid fraction obtained in the first step is not particularly limited. For example, the solubilized product obtained in the third step The liquid fraction obtained in the first step may be a mixing ratio of 50 parts by weight or more with respect to 1 part by weight of the processed product.

  In this 4th process, the methane fermentation process by an upflow anaerobic sludge bed method is implemented according to the method conventionally employ | adopted in waste water treatment. As a specific example of the methane fermentation treatment by the upflow anaerobic sludge bed method, granule sludge containing methane fermentation bacteria is introduced, the liquid fraction obtained in the first step and the solubilization obtained in the third step An example is a method in which the mixed solution with the treated product is passed through so that the residence time is 1 to 24 hours, preferably 4 to 8 hours. In addition, the temperature conditions in the methane fermentation treatment by the upward flow anaerobic sludge bed method can be appropriately set from a wide temperature range depending on the type of methane fermentation bacteria contained in the granular sludge, and are particularly limited. However, in general, it may be about 20 to 60 ° C., for example, a so-called intermediate temperature of about 30 to 35 ° C. or a so-called high temperature of about 50 to 55 ° C. may be used.

  The wastewater discharged after being treated in this manner has a reduced organic matter concentration, can be discharged into the sewer, and has been purified to such an extent that it does not adversely affect the environment.

II. Disposal Device The present invention also provides a disposer wastewater treatment device for carrying out the above treatment method.

  The treatment apparatus of the present invention includes a solid-liquid separation device 1 that separates the disposer waste water into a solid fraction and a liquid fraction, and a methane fermentation tank 2 that performs methane fermentation on the solid fraction separated by the solid-liquid separation device 1. A solubilization tank 3 for solubilizing methane fermentation sludge discharged from the methane fermentation tank 2, a liquid fraction separated by the solid-liquid separator 1, and a solubilized product discharged from the solubilization tank 3. The mixing tank 4 which mixes, and the upward flow methane fermentation processing tank 5 which performs the methane fermentation process of the liquid mixture discharged | emitted from the mixing tank 4 by an upflow anaerobic sludge bed method are characterized by the above-mentioned. One embodiment of the processing apparatus of the present invention is shown in FIG.

  The solid-liquid separation device 1 is configured to be able to discharge a solid fraction and a liquid fraction, which are supplied with disposer waste water and separated into solid and liquid, respectively. In the processing apparatus of the present invention, in order to enable the solid fraction and the liquid fraction separated from the solid-liquid separator 1 to be conveyed to the methane fermentation tank 2 and the mixing tank 4, respectively, the solid-liquid separator 1 Supply means 11 for supplying the solid fraction separated by solid-liquid to the methane fermentation tank 2 and supply means 12 for supplying the liquid fraction solid-liquid separated by the solid-liquid separator 1 to the mixing tank 4. That's fine.

  The methane fermentation tank 2 is configured such that the solid fraction of the disposer wastewater is supplied by the supply means 11, methane fermentation of the solid fraction is possible, and methane fermentation sludge generated after the methane fermentation treatment can be discharged. Yes. In addition, in the treatment apparatus of the present invention, a supply means 21 for supplying the methane fermentation sludge discharged from the methane fermentation tank 2 to the solubilization tank 3 is provided so that the methane fermentation sludge can be conveyed to the solubilization tank 3. Just do it.

  The solubilization tank 3 is configured so that methane fermentation sludge is supplied by the supply means 21, solubilization processing of the methane fermentation sludge is possible, and solubilized products generated after the solubilization processing can be discharged. . Further, the processing apparatus of the present invention is provided with a supply means 31 for supplying the solubilized processed product discharged from the solubilized tank 3 to the mixing tank 4 so that the solubilized processed product can be conveyed to the mixing tank 4. Just do it. Furthermore, in the processing apparatus of this invention, you may provide the return means 32 for returning a part of solubilization processed material discharged | emitted from the solubilization tank 3 to the methane fermentation tank 2, Thereby, solubilization process Part of the product can be subjected again to the methane fermentation treatment, and the decomposition efficiency of organic matter can be improved.

  The mixing tank 4 is supplied with the liquid fraction of the disposer drainage by the supplying means 12, and further supplied with the solubilized processed product by the supplying means 21, and can mix the liquid fraction and the solubilized processed product. It is configured so that it can be discharged. Moreover, in the processing apparatus of this invention, in order to be able to convey the said liquid mixture to the upward flow methane fermentation processing tank 5, the liquid mixture discharged | emitted from the mixing tank 4 is supplied to the upward flow methane fermentation processing tank 5. What is necessary is just to provide the supply means 41. FIG.

  The upward flow methane fermentation treatment tank 5 is supplied with the mixed solution by the supply means 41, can be subjected to methane fermentation treatment by the upward flow anaerobic sludge bed method of the mixture, and can discharge waste water generated after the methane fermentation treatment. It is configured to be. The waste liquid discharged from the upward flow methane fermentation treatment tank 5 can be discharged into the sewer.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated, this invention is not limited to a present Example.

Example 1
After performing solid-liquid separation, methane fermentation, solubilization, and upward flow methane fermentation on the disposer wastewater, the residual organic matter concentration was measured. Specific conditions and results are as follows.
<Production of Disposer Drainage>
Each of the following materials was cut into 5 mm squares, each material was thoroughly stirred, and this was used as simulated garbage.

・ Fruits Apple 2.5%
Orange (skin) 7.5%
Banana (skin) 10%
・ Vegetable cabbage 10%
Potato 10%
Carrot 10%
Radish 10%
Chinese cabbage 10%
・ Meat minced meat 2.5%
・ Seafood Fish 3.5%
Bone 1.5%
・ Eggs Egg 2.5%
・ Remaining rice 10%
Bread 2.5%
Noodles 7.5%
The unit “%” of the composition of simulated raw garbage indicates weight%.

  Disposer drainage was obtained by pulverizing 1 kg of the above simulated garbage with flowing 10 L of water using a laboratory sink (a sink) equipped with a disposer.

<Disposer wastewater purification treatment>
1. Solid-liquid separation Solid-liquid separation was performed by passing the disposer wastewater through a 0.5 mm mesh screen. The recovered amount and SS (Suspended Solid) concentration of the solid fraction and the liquid fraction thus separated were as shown in Table 1. The collected solid fraction and liquid fraction were each stored at 4 ° C. under sealed conditions until subjected to the next treatment.

2. Methane fermentation and solubilization
100 ml of the solid fraction recovered from the disposer effluent was charged into a 2400 ml methane fermentation tank (anaerobic, 55 ° C.) for methane fermentation. One day after the start of methane fermentation, 100 ml of methane fermentation sludge was extracted from the inside of the methane fermentation tank, put into a 120 mL solubilization tank, and heated at 80 ° C. for solubilization treatment. At the same time, a new methane fermentation tank (anaerobic, 55 ° C.) was charged with 100 ml of the solid fraction recovered by solid-liquid separation, and methane fermentation was performed.

  Next, one day after the start of the new methane fermentation and solubilization treatment, 100 ml of the solubilized treatment product inside the solubilization tank is extracted, and then 100 ml of the methane fermentation sludge inside the methane fermentation tank is moved to the solubilization tank. A heat solubilization treatment at 0 ° C. was performed. Furthermore, 100 ml of a solid fraction recovered by solid-liquid separation was newly added into the methane fermentation tank, and methane fermentation treatment (anaerobic, 55 ° C.) was performed. By repeating this operation for 40 days, methane fermentation treatment (anaerobic, 55 ° C.) and solubilization treatment (heating at 80 ° C.) were continuously carried out. The solubilized product extracted from the inside of the solubilization tank was stored at 4 ° C. under sealed conditions.

3. Upstream methane fermentation 200 mL of the solubilized product obtained above (solubilized product collected 39 days and 40 days after the start of the first methane fermentation) and the liquid fraction recovered by solid-liquid separation 1800 ml was mixed to obtain 2000 ml of a mixture of the solubilized product and the liquid fraction of the disposer drainage. This mixed solution was subjected to methane fermentation treatment by an upflow anaerobic sludge bed method using a UASB apparatus (55 ° C.) having a tank volume of 300 ml and a residence time of 2 hours.

  As a result, the wastewater discharged from the UASB (upstream anaerobic sludge blanket) device has a COD concentration of 205 mg / L and an SS concentration of 70 mg / L, which is a concentration that can be discharged into sewers without aerobic treatment. It was.

Comparative Example After performing solid-liquid separation, methane fermentation, and upward flow methane fermentation on the disposer waste water used in Example 1, the residual organic matter concentration was measured. That is, the processing conditions of this comparative example 1 differ from the said Example 1 by the point which does not perform a solubilization process after methane fermentation. Solid-liquid separation conditions, methane fermentation conditions, and upflow methane fermentation conditions and results are as follows.

1. Solid-liquid separation and methane fermentation treatment Solid-liquid separation was performed under the same conditions as in Example 1, and methane fermentation was performed on the obtained solid fraction under the same conditions as in Example 1 to obtain methane fermentation sludge.

2. Upstream methane fermentation 200 mL of the methane fermentation sludge obtained above and 1800 ml of the liquid fraction recovered by solid-liquid separation were mixed to obtain 2000 ml of a mixed liquid of the liquid fraction of methane fermentation sludge and disposer drainage. . The mixed liquid was subjected to methane fermentation treatment by the upward flow anaerobic sludge bed method under the same conditions as in Example 1.

  As a result, the COD concentration of the wastewater discharged from the UASB device was 678 mg / L, and the SS concentration was 90 mg / L, which was an organic matter concentration that required further aerobic microbial treatment to be discharged into the sewer. .

It is a figure which shows one Embodiment of the processing apparatus of this invention.

Claims (5)

A method for treating wastewater containing soot that has been pulverized by a disposer, including the following steps:
A first step of solid-liquid separation of waste water containing soot that has been pulverized by a disposer into a solid fraction and a liquid fraction;
A second step of subjecting the solid fraction obtained in the first step to a methane fermentation treatment,
The third step of solubilizing the methane fermentation sludge obtained in the second step and the liquid fraction obtained in the first step and the solubilized product obtained in the third step are mixed, and the upward flow The 4th process used for methane fermentation processing by an anaerobic sludge bed method. The processing method according to claim 1, wherein a part of the solubilized product obtained in the third step is again subjected to the methane fermentation treatment in the second step. The treatment method according to claim 1, wherein the solubilization treatment in the third step is a heat treatment under a temperature condition of 70 ° C. or higher. In the fourth step, the liquid fraction obtained in the first step is mixed with 1 part by weight of the solubilized product obtained in the third step at a mixing ratio of 50 parts by weight or more, and this is an anaerobic upflow The processing method according to claim 1, which is a step for subjecting to a methane fermentation process by a sludge bed method. A solid-liquid separation device that separates wastewater containing soot that has been pulverized by a disposer into a solid fraction and a liquid fraction;
A methane fermentation tank for performing methane fermentation on the solid fraction separated by the solid-liquid separator,
A solubilization tank for solubilizing methane fermentation sludge discharged from the methane fermentation tank;
A mixing tank for mixing the liquid fraction separated by the solid-liquid separator and the solubilized product discharged from the solubilization tank;
An upward flow methane fermentation treatment tank that performs methane fermentation by the upward flow anaerobic sludge bed method for the mixed liquid discharged from the mixing tank,
An apparatus for treating wastewater containing soot that has been pulverized by a disposer.

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