JPH1133589A - Apparatus for treating excrement wastewater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus for treating excrement wastewater which enables measures for purification tank sludge sufficiently and can attempt the stabilization of biotreatment. SOLUTION: A treatment apparatus for excrement wastewater has pretreatment means 1, 2 which introduces excrement wastewater containing at least raw excrement and purification tank sludge and removes contaminants, a prereaction means 3 for oxidation-treating the excrement wastewater treated by the pretreatment means 1, 2, a reaction means 4 for nitrification- denitrification-treating the excrement wastewater treated by the prereaction means 3, and a solid-liquid separation means 5 for solid-liquid separating the suspension sent from the reaction means 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for treating human wastewater containing raw human waste and septic tank sludge, and more particularly to an apparatus for treating human wastewater that can sufficiently cope with septic tank sludge.

[0002]

2. Description of the Related Art Generally, human wastewater has a high content of impurities, a high concentration of organic substances, a relatively large amount of water, and a large load variation.

Conventionally, as a general method of treating human wastewater having such characteristics, a foreign substance is removed in a pretreatment step.
A method is known in which biological treatment (nitrification and denitrification treatment) is performed, and then advanced treatment is performed, if necessary, to release or reuse.

For example, Japanese Unexamined Patent Publication (Kokai) No. 61-146397 discloses a method in which human waste and sludge from a septic tank are received in a receiving tank and subjected to a sand settling process. A method for performing solid-liquid separation by an ultrafiltration membrane and performing a high-level decolorization treatment with activated carbon is disclosed.

[0005] However, in recent years, even in distant urban areas, due to the wave of urbanization, household toilets have been washed with water.
The volume of collected urine (raw human urine) is decreasing, and instead, the volume of merged septic tank sludge, represented by agricultural settlement wastewater treatment facilities, is increasing rapidly.

[0006] In human waste treatment facilities, it is obligatory to treat raw urine and septic tank sludge. However, there is a problem that the properties of septic tank sludge are not stable, and there is a problem that biological treatment is not stable.

[0007]

Problems to be Solved by the Invention
The method described in Japanese Patent Publication No. 97 is an epoch-making treatment method capable of nitrifying and denitrifying by reducing the amount of ss in human wastewater, but it cannot be said that measures for septic tank sludge are sufficient. There are still issues to be solved in stabilization of the system. Therefore, an object of the present invention is to provide a treatment device for a wastewater treatment system capable of sufficiently stabilizing a biological treatment by enabling measures against a septic tank sludge.

[0008]

A wastewater treatment apparatus according to the present invention for solving the above-mentioned problems comprises a pretreatment means for introducing wastewater containing at least raw urine and septic tank sludge to remove impurities, A pre-reaction means for oxidizing the human wastewater treated by the pretreatment means, a reaction means for nitrifying and denitrifying the human waste water treated by the pre-reaction means, and a solid-liquid suspension fed from the reaction means. Solid-liquid separation means for separating.

In a preferred embodiment of the present invention, the solid-liquid separation means is a membrane separation means, and the pre-reaction means has a residence time of 1 hour relative to the amount of water when human wastewater is continuously introduced. At least a pre-reactor having a capacity not less than three days or more, a circulating pump for extracting human wastewater from the pre-reactor to the outside and returning it to the pre-reactor, and a mixing unit for mixing air into a circulating line. In still another preferred embodiment, the pre-reaction means has a pre-reaction tank having a capacity of 1 day or more and 3 days or less with respect to the amount of water when human wastewater is continuously introduced, And a diffuser provided in the pre-reaction tank.

[0010]

Embodiments of the present invention will be described with reference to the accompanying drawings.

The human wastewater to be treated according to the present invention contains at least raw urine and septic tank sludge, and the septic tank sludge can include a combined septic tank sludge. Further, in the present invention, human wastewater composed of septic tank sludge or raw human waste can include miscellaneous wastewater.

FIG. 1 is a block diagram showing an example of a treatment apparatus according to the present invention. In FIG. 1, reference numeral 1 denotes first pretreatment means for introducing sludge from a septic tank to remove impurities, and 2 for introducing raw urine. This is a second pretreatment means for removing impurities.

The first and second pretreatment means 1 and 2 are composed of sand,
It is a means for removing contaminants such as stones, paper, fibers, rubber products, hair, and other debris, and may take various means. The first and second pre-processing means 1 and 2 may be provided separately, but one may be shared.

FIG. 2 shows a preferred flow of the apparatus used in the process from the reception of raw urine and septic tank sludge to the pre-reaction. In the figure, septic tank sludge and raw urine are separately received on a primary screen 101 by a vacuum vehicle (not shown).

In the primary screen 101, contaminants are separated under pressure by using the pressing force of a vacuum car, and raw urine and septic tank sludge are separately received in the receiving tanks 102, 103, and from the receiving tanks 102, 103. It is sent to a decanter 107 via pumps 104 and 105. The wastewater from which contaminants are separated by the decanter 107 is supplied to a livestock storage tank 108 and a septic tank sludge storage tank 109.
Are each accepted.

On the other hand, the impurities separated by the primary screen 101 are sent to a drum screen 106, dewatered by a screw press 106A, and the separated liquid is sent to a receiving tank 103.
The residue separated by the screw press 106A is separately processed.

[0017] Raw and manure storage tank 108 and septic tank sludge storage tank 109
The liquid is sent to the next pre-reaction means 3 via the pumps 110 and 111 in fixed amounts.

The prereaction means 3 oxidizes the human wastewater treated by the pretreatment means 1 and 2 (also called an aerobic treatment if necessary), and treats the human wastewater in a subsequent biological treatment (nitrification and denitrification treatment). Specifically, the organic substance contained in the human wastewater is oxidatively decomposed by the pre-reaction to lower the liquid viscosity, thereby improving the solid-liquid separation property.
In addition, high molecular organic matter is oxidatively decomposed by the pre-reaction to suppress malodor.

As a pre-reaction means for carrying out the oxidation treatment, as shown in FIG. 3, a pre-reaction tank 301 is provided, and the wastewater is drawn out of the pre-reaction tank 301 by a circulation pump 302, and the pre-reaction is performed again. A preferred example is a method in which air is mixed into the circulation line by providing the air mixing section 303 in the process of returning to the tank 301, and air is mixed into human wastewater in the pre-reaction tank.

Although not shown, it is also preferable to provide a diffuser tube in the prereaction tank, supply air to the diffuser tube, and mix air into human wastewater in the prereaction tank.

In the present invention, by performing such an oxidizing treatment, the environment becomes incapable of inhabiting the anaerobic bacteria in human wastewater, and the subsequent biological treatment and membrane treatment are stabilized.

Normally, human wastewater contains a large number of putrefactive bacteria and obligate anaerobic bacteria, and is often in a so-called rotten state. When the reaction (including nitrification denitrification treatment) is performed, the tendency of the activated sludge in the biological reaction tank to increase in viscosity increases as the concentration increases. Activated sludge having increased viscosity is difficult to control the concentration, and even if air is blown, the air does not dissolve and is not effectively used. Therefore, biological treatment is not stable, and not only decomposition of organic matter but also nitrification and denitrification are incomplete, causing a problem that the treatment is not stabilized. In addition to the instability of such biological treatment, sludge adhering to the membrane surface cannot be easily washed even by membrane treatment, causing a problem that the membrane flux is reduced and stable membrane treatment cannot be continued. Although there was a problem in terms of stabilization, the pre-reaction tank of the present invention could solve such a problem.

In the present invention, the tank capacity of the pre-reaction tank is
It is preferable that the retention time with respect to the amount of water when the human wastewater is continuously introduced is set to a capacity of 1 day or more and 3 days or less. 1
If the number of days is more than one day, not only will the load fluctuation of the wastewater be suppressed, but also the environment in which one or more of the facultative anaerobic or aerobic bacterial cells contained in the wastewater of the human waste are the preferred species. Because you can make it. If the capacity is too large, the cost is increased.

The biological reaction means 4 following the prereaction means 3 is mainly constituted by a nitrification and denitrification treatment tank, and the constitution of the nitrification and denitrification treatment tank is not particularly limited.

In the present invention, the presence of the above-mentioned pre-reaction means 3 makes it possible to stabilize the biota in the nitrification and denitrification treatment tank without causing an increase in viscosity, thereby enabling a stable treatment.

Reference numeral 5 denotes a solid-liquid separation means. As the solid-liquid separation means, a gravity sedimentation type sedimentation tank or a membrane separation means can be adopted, and may be selected according to the requirements of the properties of the treatment liquid. In this example, a case where a membrane separation unit is employed will be described.

The membrane separation means is a means for solid-liquid separation of the suspension (activated sludge) sent from the biological reaction means 4. However, as described above, since the treatment in the nitrification and denitrification treatment tank is stabilized, the membrane is separated. Clogging is reduced, the effect of recovering the film flux by washing is stabilized, and the film treatment can be stabilized.

The type of the membrane used for the membrane separation means may be any of an ultrafiltration membrane, a microfiltration membrane, a reverse osmosis membrane, etc., and may be used in a tank installation type (so-called submerged membrane type) or the like. It may be installed outside. Further, the type of the membrane may be any of a flat membrane and a tubular membrane.

The activated sludge is separated into a permeate and a concentrated sludge by the membrane separation means. The concentrated sludge is returned to the reaction means 4 and a part thereof is concentrated as surplus sludge or
After being sent to the dehydrator 9 and dewatered, it is effectively used as compost fertilizer or the like.

The separated liquid separated by the dehydrator 9 is returned to the biological reaction means 4 and reprocessed.

The permeate separated by the membrane separation means is subjected to further advanced treatment if necessary. For example, the decolorization treatment is performed mainly in the activated carbon treatment means 8 via the solid-liquid separation means 7 via the phosphorus removal treatment means 6 as shown in the drawing, and the treated water is reused or discharged. In the dephosphorization treatment means 6, iron chloride or a polyiron-based coagulant is added, the phosphorus component in the permeate is subjected to coagulation treatment, and the solid-liquid separation means 7 separates and removes it. As the solid-liquid separation means 7, a membrane treatment may be used, or a sedimentation tank of a gravity sedimentation type may be used, but preferably a membrane treatment capable of automatic control operation. The film used for the film treatment may be the same as the film described above.

[0032]

An embodiment of the present invention will be described. The present invention is not limited by such embodiments.

Example 1 Raw human waste (average 17.3 t / D) and septic tank sludge (average 13.8 t / D)
D) and human wastewater (average: 31.1 t / D) was received in the apparatus shown in FIG. 1 and pretreated as follows.

The transported night soil and septic tank sludge are sent to the primary screen using the discharge pressure of the vacuum truck to remove stones and foreign matter. Then, the residue is removed with a drum screen. The separated liquid is further subjected to a centrifugal separator (sand separator) to remove fine sand and fibers.

The properties of human wastewater at the sand separator inlet are as shown in Table 1.

Each property of the waste water is shown as it is by four analysis values at one week intervals. The unit of each value is ppm.

[0037]

[Table 1]

The properties of human wastewater at the outlet of the sand separator are as shown in Table 2.

Each property of the wastewater is shown as it is by four analysis values at one week intervals. The analysis date is the same as Table 1.

[0040]

[Table 2]

Next, the pretreated human wastewater (raw human waste 1)
Consisting of 7.3 t / D and septic tank sludge of 13.8 t / D, total volume averaged 31.
1 t / D) was received in the pre-reactor. A circulating air injection device was added to the pre-reaction tank so that air could be supplied into the pre-reaction tank. The residence time in the pre-reaction tank was 48 hours.

The properties of human wastewater in the pre-reaction tank are as shown in Table 3. Each property of the wastewater is shown as an analysis value three times at one week intervals. The date of analysis is shown in Table 1
Same as the day on which the fourth analysis was performed.

[0043]

[Table 3]

Next, the product was sent to a biological reaction tank, where nitrification and denitrification treatment was performed, and then ultrafiltration membrane treatment was performed. However, operation of the biological reaction tank was smooth, no increase in viscosity was observed, and membrane treatment was also smooth. I did it.

The properties of the treated water after the membrane treatment are as shown in Table 4. Each property of the wastewater is shown as an analysis value three times at one week intervals. The analysis dates are shown in Table 1
Same as the day on which the second analysis was performed.

[0046]

[Table 4]

Comparative Experiment In the above experiment, when the pre-reaction tank was not provided, the viscosity increased in the biological reaction tank, and the flux in the membrane treatment decreased, so that stable operation could not be performed for a long time. .

[0048]

As described above, according to the present invention, the present invention makes it possible to sufficiently take measures against sludge in a septic tank, stabilize biological treatment, and provide an apparatus for treating urine wastewater.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an example of a processing apparatus according to the present invention.

FIG. 2 is a flowchart showing an example of a preprocessing unit.

FIG. 3 is an explanatory view showing an example of a pre-reaction tank.

[Explanation of symbols]

 1: first pretreatment means 2: second pretreatment means 3: prereaction means 4: reaction means 5: solid-liquid separation means 6: dephosphorization treatment means 7: solid-liquid separation means 8: activated carbon treatment means

Claims (4)

[Claims] 1. A pretreatment means for introducing wastewater containing at least raw urine and septic tank sludge to remove impurities, a prereaction means for oxidizing the wastewater treated by the pretreatment means, and An apparatus for treating human waste wastewater, comprising: a reaction means for subjecting human wastewater treated by the reaction means to nitrification denitrification treatment; and a solid-liquid separation means for solid-liquid separating a suspension sent from the reaction means. 2. An apparatus for treating human waste water according to claim 1, wherein said solid-liquid separation means is a membrane separation means. 3. A pre-reaction tank, wherein said pre-reaction means has a capacity of a residence time of not less than 1 day and not more than 3 days with respect to the amount of water when human waste water is continuously introduced; 3. The human wastewater treatment apparatus according to claim 1 or 2, comprising at least a circulation pump taken out of the apparatus and returned to the pre-reaction tank, and a mixing unit for mixing air into the circulation line. 4. The pre-reaction means is provided in a pre-reaction tank having a capacity of a residence time of 1 day or more and 3 days or less with respect to the amount of water when human wastewater is continuously introduced, and in the pre-reaction tank. 3. An apparatus for treating human wastewater according to claim 1, wherein the apparatus is at least constituted by an air diffuser.