JP2008221179A - Drainage treatment method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drainage treatment method capable of obtaining an improved result. <P>SOLUTION: The drainage treatment method uses microorganisms, and is characterized in that drainage is treated in the presence of a treatment agent comprising an extracted component(s) from at least one kind of plant selected from an extracted component from Sapindus mukurossi and an extracted component from Saikachi. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention preferably includes wastewater containing oil and / or SS at a high concentration such as oily wastewater, starchy wastewater or combined tank wastewater, sewage from kitchen wastewater, food processing plants, etc. The present invention relates to a wastewater treatment method in which the oil component and / or SS component to be treated is partially removed without being previously removed.

  The biological treatment method is a kind of treatment method of wastewater by microorganisms, and is a treatment method in which microorganisms adhere to the surface of a contact filter medium as a carrier stored in a tank or a tower, and organic matter in wastewater is decomposed by the microorganisms. In a preferred embodiment, microorganisms are attached to the contact filter medium in a form called a so-called biofilm, and in this case, it is also called a biofilm treatment method. Biofilm treatment methods include contact aeration, rotary contact aeration, sprinkling filter beds and the like. Of these, the contact aeration method is widely used. In this case, a contact filter medium (a member in the form of a plastic plate, string, etc.) is fixed in an aeration tank, and microorganisms are applied to the surface thereof, for example. Used in a film form. In another embodiment, a relatively small contact filter medium is suspended, and the contact filter medium to which microorganisms adhere by aeration from the bottom of the tank is used by stirring.

  When wastewater is treated by the contact aeration method, if the oil contains a large amount of oil, the oil adheres to the contact filter medium and the biofilm attached to the surface of the wastewater, thereby hindering its activity. Specifically, the oil blocks the access to water and air microorganisms, and there is a risk that the treatment becomes impossible. Even when the SS content is large, the SS content may adhere to the surface of the contact filter medium or the biofilm, and similarly, the access to water or air may be blocked to make the treatment impossible. Such a problem is a problem that occurs not only in the contact aeration method but also in wastewater treatment using microorganisms attached to the contact filter medium. In the case of the contact aeration method, a large amount of oxygen is required to support the active activity of microorganisms, and much power is consumed.

  Therefore, prior to the biofilm treatment with the contact filter medium, pretreatment is performed in order to reduce the content of oil and / or SS in the wastewater. In the case of the contact aeration method, the upper limit is 20 ppm as the normal hexane extract. Most of the oil and / or SS is removed by pressurized levitation.

  This pressurized flotation process requires a large amount of flocculant and also requires a large amount of power to introduce pressurized air. In addition, aerated air emits malodors into the surrounding atmosphere. Furthermore, there are various problems such that the separated oil rots and gives off a bad odor, and that it takes time to process such oil.

  A further problem with pressure levitation is that the oil and / or SS components cannot be removed sufficiently. Conventionally, aeration is carried out for a long time or a large amount of flocculant is added to reduce the amount as much as possible. However, it is said that it is not easy to make the normal hexane extract 30 ppm or less. Therefore, in the subsequent biofilm treatment, the contact filter medium is often covered with oil and / or SS, or access to the contact filter medium is blocked, resulting in inability to process. In such a case, there is no countermeasure other than removing the contact filter medium.

  In order to solve such problems, it has been proposed that wastewater is supplied to a contact filter medium tank together with a saponin-containing agent to decompose oil and / or SS by living organisms (that is, so-called microorganisms) (the following patents). Reference 1). By using a saponin-containing agent, it is said that wastewater treatment can be performed without performing a pretreatment for removing oil and / or SS. Here, the saponins disclosed to be usable are saponins obtained from Kiraya saponin, yucca, nagura squid, soybean, sugar radish, but the only saponin actually used in the examples is Kiraya saponin.

Japanese Patent No. 3752603

  Thus, it is said that by using Kirayasaponin, wastewater can be treated without pretreatment. However, such wastewater treatment is not always satisfactory, and it is further desirable to provide a wastewater treatment method that provides improved results. Therefore, the problem to be solved and used by the present invention is to provide a further improved wastewater treatment with a biofilm.

  As a result of the inventor's extensive studies on the above problems, the treatment agent containing the extract component from Mukuroji and / or the extract component from Saikachi is a microorganism, preferably a microorganism used as a biofilm in the wastewater to be drained The present inventors have found that there is an effect of improving the oxygen supply capacity of the air diffuser and an effect of improving the oxygen supply capacity of the air diffuser in the aeration tank. And it discovered that such an effect was especially useful for the waste water treatment method, and completed this invention.

Without using a pretreatment to remove oil and / or SS by using a treatment agent containing at least one kind of extract component from this mugwort or extract from honey locust. Waste water treatment becomes possible.
In addition, since the extract component from Mukuroji or the extract component from Saikachi contains saponin having a surface-active effect derived from nature, increasing the dissolved oxygen concentration in the wastewater by supplying it to the contact filter media tank It is possible to decompose oil.

  In the first aspect, the present invention is a wastewater treatment method using a microorganism, for example, a biofilm, which treats wastewater in the presence of a treatment agent containing an extract component from Mukuroji and / or an extract component from Saikachi. A wastewater treatment method is provided. The treatment with microorganisms is particularly preferably performed with a contact filter medium having a so-called biofilm. In a particularly preferable waste water treatment method of the present invention, a waste water treatment method using a living organism, wherein waste water is treated in the presence of a treatment agent comprising an extract component containing at least one of saponin derived from mukuroji and saponin derived from saikachi. To do.

  In the second aspect, the present invention is a method for improving the oxygen supply capacity to microorganisms in the wastewater to be treated, and the presence of an extract component from Mukuroji and / or an extract component from Saikaichi in the wastewater. A method is provided. By adding the above-mentioned treatment agent to the waste water, an extract component from Mukuroji or an extract component (for example, saponin) from Saikachi can be present. In other words, the present invention provides an agent for improving oxygen supply capacity in wastewater, comprising at least one saponin of mukuroji saponin and saikachi saponin.

  Although the present invention will be described mainly with respect to the wastewater treatment method of the present invention, such description applies to the method for improving the oxygen supply capacity and the oxygen supply capacity improver of the present invention as applicable.

  In the present invention, the treatment agent containing saponin may contain an extract component from the above-mentioned mukuroji and / or an extract component from honey locust, and the extract component is dissolved or uniformly dispersed. It may be a medium such as water and / or a lower alcohol (eg ethanol). Such a medium (for example, water and / or lower alcohol) may contain other components as long as it does not adversely affect the wastewater treatment method of the present invention. As the treatment agent containing saponin, for example, an extract obtained by extracting mukuroji, honey bee, such as its fruit, bark, seed, sap, etc., with an extractant, for example, the above medium (for example, water) can be used as it is. Further, the extract can be concentrated, concentrated, dried or diluted as necessary, and used as a powder processing agent or a liquid component processing agent. Of course, the saponin itself isolated by treating the extract can be used as a treating agent as it is, or dissolved or dispersed in an appropriate medium.

  In the presence of a treatment agent containing saponin, it is sufficient that the treatment agent is contained in the wastewater to be treated. For example, even if the treatment agent is mixed in advance with the wastewater to be treated, Alternatively, a treatment agent may be mixed in the wastewater that has been treated.

  In the wastewater treatment method of the present invention, microorganisms are well known in the field of wastewater treatment and mean microorganisms and / or protozoa adapted to the degradation of oil and / or SS contained in wastewater. Specifically, it is used as a so-called biofilm attached to a contact filter medium as a carrier. Therefore, also in the wastewater treatment method of the present invention, the oil and / or SS content in the wastewater is decomposed. Usually, when wastewater treatment is started using a contact filter medium in a natural environment, such microorganisms naturally adhere to the contact filter medium and multiply to form colonies, which grow in the form of a biofilm.

  In this invention, the oxygen supply capability in waste water improves by making the said specific saponin exist in waste water using a processing agent. Therefore, when microorganisms capable of decomposing oil and / or SS in the wastewater are present in the wastewater, the ability to supply oxygen to the microorganism is improved, whereby the decomposition is promoted, and the wastewater treatment method using such microorganisms Is improved.

  Specifically, when compared with Quillaja saponin, an extract component (saponin) obtained from a plant body such as mukuroji or saikachi shows an oxygen supply capacity that is about 10% higher. Therefore, in the wastewater treatment method of the present invention, the blower count (blade size) and the motor (power source) of the air diffuser can be reduced, so that energy saving can be achieved. Furthermore, the initial cost and running cost of the blower can be kept low. Also, the oil / fat decomposing ability can be improved by 10%.

  Furthermore, when the extract component (saponin) obtained from a plant body such as mukuroji or saikachi is present in the wastewater, the odor of the wastewater can be reduced more than in the presence of kirayasaponin. This is considered to be because the activity of microorganisms in the wastewater is higher than that in the presence of Kirayasaponin, and odor components (methane gas and hydrogen sulfide gas) can be decomposed by the activity of microorganisms such as Bacillus bacteria.

BEST MODE FOR CARRYING OUT THE INVENTION

  In the present invention, the waste water is water containing oil and / or SS, or a liquid containing water as a main component (thus, an aqueous liquid that may also contain other components). Usually, domestic wastewater, industrial or industrial wastewater, etc. are included in such wastewater, and are treated water that is treated using microorganisms. In the present invention, waste water containing a large amount of oil is the main target. For example, wastewater from the food service industry, food processing factories, etc., and miscellaneous wastewater from households is also targeted.

  The oil component contained in the wastewater is a component contained in the wastewater and is a substance extracted by normal hexane (a so-called “normal hex component”). Although the water quality standard regarding the norhex component in the wastewater after the wastewater treatment is said to be several ppm, 600 to 700 ppm of the norhex component may be contained in the wastewater from the food processing factory or the restaurant industry. Further, wastewater containing a relatively small amount of oil but containing a large amount of SS, for example, a wastewater containing a large amount of starch from a noodle factory or the like, and a wastewater containing a large amount of both oil and SS are also suitable for the present invention. Become. When such wastewater is treated in the natural environment, colonies of microorganisms are gradually formed in the wastewater or on the surface of the contact filter medium, and organic substances are efficiently treated.

  In the wastewater treatment method of the present invention, it is particularly preferable to use a method for decomposing oil and / or SS by microorganisms in the presence of oxygen. Specifically, the treatment is performed under aerobic conditions. Examples of the aerobic condition treatment include an activated sludge method and a biofilm method. In the latter case, a fixed bed system may be used, and in that case, a contact aeration method, a sprinkling filter bed method, a biological filtration method, or the like may be employed. In another aspect, the fluidized bed method may be used.

  For example, in the contact aeration method, a gas containing oxygen, for example, air is supplied and aerated from below and / or from the side of a container as an aeration tank containing waste water. For example, a contact filter medium as a carrier for biofilms such as minerals, plastics, wood, and other plate-like, string-like, granular, etc. is installed in an aeration tank, and drainage is supplied into it.

  For example, when using a fluidized bed system, plastic micro containers, corks, foamed polystyrene, activated carbon, vermiculite, etc., pulp scraps, rice husks, sawdust etc. These are also used by flowing in an aeration tank, and these are agitated by aeration. The sprinkling filter bed method sprays waste water from above into a tank filled with such fine pieces.

  The specific saponin used in the present invention is extracted from a known saponin plant such as mukuroji or saikachi, such as water, lower alcohol (for example, ethanol), or an aqueous medium (for example, a mixture of water and lower alcohol). It can be obtained by extraction with a solvent. In addition, mukuroji-derived saponin is also called Enmeihi saponin. Such extraction may be carried out by a generally known extraction method and is used for obtaining various saponins, and is well known. Thus, the extract obtained by extracting can be used as a processing agent of the present invention. That is, an extract containing saponin extracted from a plant body may be used as it is for wastewater treatment as a treatment agent.

  In another embodiment, the purified product itself may be used as a treatment agent. Furthermore, the saponin which processed the refined | purified substance and the extract further, and was processed into the powder form, the granular form, or the tablet can be used. In this case, when applying to the wastewater treatment method, the treatment agent of the present invention can be prepared by being dissolved in water, wastewater or the like, if necessary.

The treating agent used in the present invention may be a specific saponin itself, or contains such saponin in a dissolved state and / or dispersed state, and is dissolved in the waste water to be treated or uniformly. It may be dispersible. In the latter case, the form is not particularly limited, and specifically, an aqueous solution or aqueous dispersion containing a specific saponin, an alcohol solution or an alcohol dispersion (in a state where saponin is dispersed in alcohol), aqueous It may be in the form of a solution or an aqueous dispersion (aqueous means containing water and other medium (for example, alcohol)) in which saponin is dissolved or dispersed.

  In the present invention, the amount of specific saponin present in the wastewater can be selected according to the amount of oil and / or SS contained in the wastewater to be treated. In general, the specific saponin is preferably from 1 ppm to 50 ppm, more preferably from 2 ppm to 20 ppm, particularly preferably from 5 ppm to 20 ppm, based on the wastewater before the start of treatment.

  For example, the oxygen supply capacity of the air diffuser can be increased by adjusting the amount of the wastewater and the addition of the treatment agent so that it exists in the wastewater at a low concentration of 0.01 ppm to 1 ppm or a concentration exceeding 50 ppm. It should be noted that the saponin concentration may be constant or change within such a range. This is because the wastewater concentration varies depending on the residence time in the aeration tank.

Drainage can be applied such saponin concentration is preferably 0.05~1.5Kg / ^{m 3} / day, and more preferably from oil volume loading of 0.05~0.7Kg / ^{m 3} / day.

  In the case of batch-type wastewater treatment, untreated wastewater and treatment agent are supplied to the treatment tank so as to be in the concentration range as described above, or mixed in advance so as to obtain the concentration as described above. A mixture of treatment wastewater and treatment agent is supplied to the treatment tank. In the case of continuous treatment, if the untreated wastewater and the treatment agent are mixed, these are continuously supplied to the treatment tank so that the concentration becomes as described above. In addition, you may implement by the semibatch system which adds at least one of waste_water | drain and a processing agent to a processing tank intermittently.

  The treatment method of the present invention can be applied to waste water that has not been subjected to any prior treatment, and in this case can be said to be a primary treatment. However, if necessary, for example, a screen may be used to remove impurities and / or in addition to the oil and / or SS components. For example, it may be preliminarily removed by pressurized flotation separation. In addition, the present invention can be used for a secondary treatment or a tertiary treatment as a biological treatment process of waste water.

  More specifically, the treatment method of the present invention can be applied to the waste water treatment process of the flow sheet shown in FIG. The raw wastewater 1 from the generation source 10 is supplied to the raw drainage tank 12 and then passed through a screen 14 to remove impurities. The permeate is adjusted in the pH adjusting tank 18 as necessary, and then sent to the contact aeration tank 20 as waste water 28 to be processed by the biofilm. The treated waste water is supplied to a sedimentation tank 22 where solid content such as sludge is removed, and after being disinfected in a disinfection tank 24 as necessary, it is discharged into a general waste water 26.

  In the waste water treatment method of the present invention, the treatment agent is supplied to the waste water 28 supplied to the contact aeration tank 20, or in addition thereto, or instead of the treatment agent in the contact aeration tank 20 so as to have the above-described saponin concentration. It is preferable to supply the waste water to treat the waste water.

(Example 1)
In order to evaluate the performance of the wastewater treatment method of the present invention, the overall oxygen transfer capacity coefficient when a specific saponin was present in the wastewater was measured. For this measurement, reference was made to “Sewage Test Methods 1997, Volume 1” (published by the Japan Sewerage Association, published on August 25, 1997), Section 11 General Oxygen Transfer Capacity Coefficients (pp. 275-277).

  Tap water was used instead of drainage. In addition, mukuroji-derived saponin, that is, Enmeihi saponin, was used as the specific saponin.

  Sodium sulfite was dissolved in tap water to obtain tap water in which the dissolved oxygen concentration in tap water was zero, and Enmayhisaponin was added thereto so that Enmeihisaponin was present in an amount of 5 ppm. Then, aeration was performed and the dissolved oxygen concentration (C) in tap water was measured. The result is shown in FIG. In FIG. 2, the difference (Cs−C) between the saturated dissolved oxygen concentration (Cs) and the dissolved oxygen concentration (C) is plotted on the vertical axis, and the elapsed time (hr) is plotted on the horizontal axis. Enmeihisaponin is written as “Mukuroji”.

  For comparison, aeration was continued without adding saponin to tap water, and the dissolved oxygen concentration in that case was measured. In addition, the dissolved oxygen concentration was also measured when Kirayasaponin was added at the same concentration instead of Enmeihisaponin. These results are also shown in FIG. About Kirayasaponin, “Kiraya” is written.

  As is clear from this result, Enmeihisaponin exhibits a large overall oxygen transfer capacity coefficient compared to other cases. The overall oxygen transfer capacity coefficient can be evaluated as a linear gradient (KLa value) when the illustrated graph is approximated by a straight line. Specifically, it means that the extractable component (saponin) obtained from Mukuroji has a high oxygen supply capacity as much as about 10% compared with Kirayasaponin.

(Example 2)
Instead of EMME torquecontrol saponin, honey locust derived saponin (Ltd. Eco Solutions Net trade _{name: ESW-1, C 30 H} 48 O 4 and _C 31 _H 50 mixture of _{O 4)} so that the concentration in water 5ppm Except for the use, the dissolved oxygen concentration was measured in the same manner as in Example 1. For comparison, measurements were also made when Kirayasaponin was added and when nothing was added. The result is shown in FIG. Similar to the case of Example 1, Saikachi-derived saponin exhibits a larger overall oxygen transfer capacity coefficient than other cases. For saponins derived from Saikachi, “Saikachi” is written. Specifically, it means that the extracted component (saponin) obtained from Saikachi has a high oxygen supply capacity as much as about 10%, compared with Kirayasaponin.

1 shows a flow sheet of a wastewater treatment process using the treatment method of the present invention. The measurement result of the general oxygen transfer capacity coefficient measured in Example 1 is shown. The measurement result of the general oxygen transfer capacity coefficient measured in Example 2 is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Original waste water, 10 ... Source, 12 ... Raw water tank, 14 ... Screen, 16 ... pH control tank,
18 ... pH adjustment tank, 20 ... Contact aeration tank, 22 ... Settling tank, 24 ... Disinfection tank,
26 ... General waste water, 28 ... Waste water.

Claims (5)

  A wastewater treatment method using microorganisms, characterized in that wastewater is treated in the presence of a treating agent containing an extract component from Mukuroji and / or an extract component from Saikachi.   The wastewater treatment method according to claim 1, wherein the wastewater treatment is performed using a biofilm attached to the contact filter medium.   The wastewater treatment method according to claim 1 or 2, wherein the treatment agent is a liquid component obtained by extracting mukuroji and / or honey locust.   The wastewater treatment method according to claim 1 or 2, wherein the treatment agent is a liquid component obtained by extracting mukuroji and / or honey locust in a solid state in a drying step.   A method of supplying wastewater to be treated to an aeration tank and improving the oxygen supply capacity of an air diffuser in the aeration tank, wherein the wastewater contains an extraction component from mud crab and / or an extraction component from honey locust A method characterized in that a treatment agent is present.

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