JP2001179297A - Apparatus for treating excretion wastewater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the subject apparatus for removing floated sludge generated when solid-liquid separation treatment is performed in a sludge sedimentation tank through a pre-reaction means to prevent the same from flowing in a reaction means of a rear stage to eliminate the fluctuations of load in the reaction means to realize stable treatment. SOLUTION: In an apparatus for treating exretion wastewater having a pre-reaction means 3 comprising a pre-reaction tank for adding a flocculant to excretion wastewater containing excretion and septic tank sludge to apply oxidation treatment thereto, a sludge sedimentation tank 6 for separating the wastewater treated by the pre-reaction means 3 into a supernatant liquid and sludge, a dehydration means 7 for dehydrating sludge separated in the sludge sedimentation tank 6, a reaction means 8 receiving the supernatant liquid separated in the sludge sedimentation tank 6 to apply nitrification/denitrification treatment thereto, a floated sludge scraper 69 is arranged to the sludge sedimentation tank 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a human wastewater treatment apparatus, and more particularly, to a human wastewater treatment apparatus for preventing deterioration of load conditions in a nitrification and denitrification treatment tank.

[0002]

2. Description of the Related Art Conventionally, human waste treatment facilities have had to complete the treatment through complicated steps for the purpose of treating a high concentration of human waste contaminants at a high level.

[0003] However, in recent years, even in distant urban areas, due to the wave of urbanization, the amount of collected urine (human waste) has rapidly decreased due to flushing of household toilets, and instead, agricultural settlement wastewater treatment facilities have been installed. The amount of the representative septic tank sludge is increasing rapidly.

[0004] The role of the human waste treatment facility is to treat human waste and septic tank sludge, and there is a need for a simplified process method corresponding to this changing situation.

The combined septic tank sludge is surplus sludge from biological wastewater treatment, and simplification of equipment can be expected by treating it together with treatment of excess sludge in a human waste treatment plant.

However, septic tank sludge has the property that its properties are not stable, the property that the dominant species of organisms differs depending on the sewage treatment method, and that the properties of surplus sludge differ.
Or, depending on the case, there is a characteristic that a toxic substance to bacterial cells is contained or a heavy metal concentration is high.

Conventionally, as a means of simplifying a human waste treatment facility,
A method has been proposed in which septic tank sludge is used as surplus sludge for urine treatment and urine is mixed and coagulated and dewatered (see Japanese Patent Publication No. 7-4598).

[0008] However, in the method described in Japanese Patent Publication No. 7-4598, the entire amount of dewatering, including excess sludge, is dehydrated. However, if such total dehydration is performed, there is a problem that the equipment becomes excessively large.
That is, it is difficult to make the dewatering operation unmanned, and because of such difficulty, if the dehydration operation is to be completed only by daytime operation, the dewatering equipment must necessarily be excessively large. In addition, if the entire amount is dehydrated as described above, the amount of the dehydrated cake naturally increases, and the treatment thereof becomes a problem. Further, there is a problem that the amount of the polymer dehydration aid must be excessively added in consideration of the maximum load in order to cope with the property change of the septic tank sludge. Furthermore, dewatered sludge contains an excessive amount of organic matter (particularly, high molecular organic matter such as protein, starch, and lipids) in urine as an excessive polymer dehydration aid. There is a problem that is easy to do. Furthermore, in recent years, guidance has been given to prohibit incineration of surplus sludge from urine treatment plants from the viewpoint of preventing environmental pollution, and treatment of surplus sludge generating odor becomes more difficult.

Therefore, as a technique for solving such a problem, it is possible to stabilize the sludge in the septic tank, to improve the decomposition of organic substances in human waste, particularly high-molecular organic substances, to improve the solid-liquid separation properties without generating odor. By improving the solid-liquid separation property, the sedimentation separation is improved, and as a result, the amount of sludge to be dewatered can be reduced, the sludge properties are stabilized, and the amount of the polymer dehydration aid added is reduced. Can be
In addition, organic matter is decomposed, so that it becomes easy to substitute for incineration such as composting of dehydrated sludge, and a treatment device for urine wastewater is proposed in Japanese Patent Application Laid-Open No. 11-33591 (hereinafter referred to as a prior proposed technology).

[0010]

It has been found that the above-mentioned proposed technology can treat raw urine and septic tank sludge at a high level, but the present inventors have continued their research and developed a more practical processing apparatus. As a result of intensive studies, the following findings were obtained. That is, looking at the actual operation of the processing apparatus according to the prior proposed technology, human wastewater containing human waste and septic tank sludge is pre-reacted in the prereaction tank, and is separated into a supernatant liquid and sludge in a sludge sedimentation tank. The liquid is subjected to a nitrification denitrification treatment in a nitrification denitrification tank in the next step. The sludge separated in the sludge sedimentation tank is dewatered by dewatering means, and the separated dewatered filtrate is once stored,
It is quantitatively returned to the nitrification denitrification tank in the same manner as the above supernatant, and is subjected to nitrification denitrification. The nitrogen load of the dehydrated filtrate is not very large when analyzed and does not contribute to increasing the load. However, when examining the load conditions at the inlet of the nitrification denitrification tank, it was found that there was a large fluctuation in the load conditions, which affected the treatment.

The present inventors have searched for the cause and obtained the following findings. That is, the nitrogen components in wastewater (e.g. NH ₄ ^+, etc.) is oxidized in the previous reaction (nitrification), becomes NO _X, into the sludge settling tank in this form. The facultative anaerobic bacteria contained in the sludge settled in the sludge settling tank consumes oxygen (O) in NO _X in a settled state. For this reason, N ₂ gas is generated, and the gas adheres to the sludge and floats up, resulting in floating sludge (this floating sludge is sometimes referred to as scum in this specification). For this reason, the sludge that should be dewatered originally enters the nitrification and denitrification tank in the next step, changing the load conditions, and hindering stable treatment.

Accordingly, an object of the present invention is to provide an apparatus for treating urine wastewater, which can eliminate such factors of load fluctuation and can realize stable treatment.

[0013]

The apparatus for treating human wastewater according to the present invention which solves the above-mentioned problems comprises a pre-reaction tank comprising a pre-reaction tank for adding a coagulant to human waste wastewater containing human waste and septic tank sludge and oxidizing the waste water. Means, a sludge sedimentation tank for solid-liquid separation of the wastewater treated by the pre-reaction means into a supernatant liquid and sludge, a dewatering means for dewatering the sludge separated in the sludge sedimentation tank, and a separation in the sludge sedimentation tank An apparatus for treating human wastewater having a reaction means for introducing the supernatant liquid obtained for nitrification and denitrification, wherein a floating sludge scraper is installed in the sludge settling tank.

In a preferred embodiment of the present invention, the coagulant comprises two types, a coagulant containing an iron component and a coagulant containing a silica component.

[0015]

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

The human wastewater to be treated according to the present invention includes at least human waste and septic tank sludge, and the septic tank sludge can include a combined septic tank sludge. In the present invention, human wastewater composed of septic tank sludge or human waste may include miscellaneous wastewater.

FIG. 1 is a block diagram showing an example of the embodiment of the present invention.

FIG. 1 shows an example of receiving both night soil and septic tank sludge. In FIG. 1, reference numeral 1 denotes a first pretreatment means for introducing septic tank sludge to remove impurities.
This is a second pretreatment means for removing the foreign substances by introducing isola.

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 the configuration is not limited.

The first and second pre-processing means 1, 2 may be provided separately, but one may be shared.

In the present invention, reference numeral 3 denotes a pre-reaction means comprising a pre-reaction tank, and the pre-reaction means 3 is for subjecting human wastewater to a reaction treatment prior to a subsequent biological treatment (nitrification and denitrification treatment). Specifically, the organic matter contained in the human wastewater is oxidatively decomposed by the pre-reaction to lower the liquid viscosity and improve the solid-liquid separation property. In addition, high molecular organic matter is oxidatively decomposed by the pre-reaction to suppress malodor. In addition, the pre-reaction causes an environment in which one or two or more aerobic bacteria or facultative anaerobic bacteria occupy the dominant species, suppresses anaerobicization of the septic tank sludge, and stabilizes the properties.

As a pre-reaction means for carrying out such an oxidation treatment, as shown in FIG. 2, a pre-reaction tank 301 is provided, and urine wastewater is drawn out of the pre-reaction tank 301 by a circulation pump 302 to the outside, and the pre-reaction is performed again. A preferred example is a method in which air is mixed into the circulation line by providing an air mixing unit 303 in the process of returning to the tank 301, and air is mixed into human wastewater in the pre-reaction tank 301.

Although not shown, a method is also preferable in which an air diffuser is provided in the pre-reactor 301, air is supplied to the diffuser, and air is mixed into the human wastewater in the pre-reactor 301.

4 is a facility for adding a coagulant containing an iron component, and 5 is a facility for adding a coagulant containing a silica component.

Examples of the coagulant containing an iron component include ferric polysulfate (polyiron), ferric chloride and the like. The coagulant containing the iron component functions as a dephosphorizing agent when added to human wastewater.

As a flocculant containing a silica component, first, a solution of an inorganic salt containing a silica component and a magnesium component can be used. For example, a mixed solution of a silicate and a magnesium salt can be used.

Secondly, as a flocculant containing a silica component, it is also preferable to use a silica-based flocculant obtained from a silica-based raw material composed of a silica composite crystal mineral and an amorphous mineral. As such a silica-based flocculant, there is a method in which blast furnace slag or the like is dissolved in a reducing acid or a neutral acid, preferably diluted sulfuric acid. As a specific example of the dissolving method, see Japanese Patent No. 255859.
The method described in No. 1 is exemplified. In addition, as a coagulant containing a silica component, a crystalline mineral containing a silica component, for example, trade name "Mineral Panny" can be used.

Third, as a coagulant containing a silica component, thirdly, a soil compact mainly composed of humus can be used.

The amount of the coagulant containing the silica component is preferably in the range of 1.0 to 200 mg / l as silica with respect to the mixed liquid of night soil, septic tank sludge and excess sludge.

As a flocculant containing a silica component, silica (Si
O ₂ ), calcium, magnesium, and aluminum are contained as main components, and these components contribute to coagulation of human waste and septic tank sludge and dominance of useful bacteria.

In the present invention, when polyiron, which is usually used as a coagulant containing an iron component, is used, if sludge is separated without passing through the pre-reaction means 3, the reaction will take place in a reducing atmosphere. However, there is a problem that polyiron does not function as a flocculant. That is, if air is not supplied, the atmosphere becomes a reducing atmosphere. In the reducing atmosphere, iron easily forms a complex with an organic substance and does not form iron phosphate.

On the other hand, if the pre-reaction treatment is performed by the pre-reaction means 3 as described above, the pre-reaction treatment will be in an oxidized state and will not oxidize and decompose organic substances to form an iron complex. The dephosphorization effect is further improved. Further, in the present invention, the equipment cost is greatly reduced as compared with the case where the dephosphorization means after nitrification denitrification is separately provided.

When a coagulant containing the above-mentioned silica component is used in combination as the coagulant, useful facultatively anaerobic bacteria (specifically, Bacillus sp.) Become dominant species in the pre-reaction tank. In addition, it becomes difficult for anaerobic bacteria and spoilage bacteria to survive. Therefore,
The combined use of a flocculant containing a silica component as a flocculant, even for strongly anaerobic sludge such as septic tank sludge,
This is a preferred embodiment because the properties are stabilized by the facultative anaerobic useful bacteria becoming the dominant species. Since the above-mentioned useful bacteria are excellent in decomposability of high-molecular organic substances (proteins, starch, lipids, etc.), the reaction does not proceed in the anaerobic direction, which also makes it difficult for the anaerobic bacteria and spoilage bacteria to survive. It can prevent putrefaction odor.

In the present invention, the tank capacity of the pre-reaction tank is the amount of water when human wastewater is continuously introduced (in the present invention, the water amount is the water amount of a mixed liquid of human wastewater and excess sludge consisting of human waste and septic tank sludge). Dwell time is 1
It is preferable that the capacity be not less than three days and not more than three days. An environment where not more than one day not only suppresses fluctuations in the load of human wastewater, but also one or two or more of the bacteria contained in the human wastewater are facultatively anaerobic or oxidized. Because you can make it. If the capacity is too large, the cost will increase, so it is within 3 days, preferably within 2 days.

After the prereaction treatment by the prereaction means 3, the sludge sedimentation tank 6 for solid-liquid separation of the treated wastewater into a supernatant liquid and sludge, and a dewatering means 7 for dewatering the sludge separated in the sludge sedimentation tank 6 And

As the sludge settling tank 6, an ordinary gravity settling tank can be used. FIG. 3A is a longitudinal sectional view showing an example of the sludge settling tank 6 according to the present invention.

The sludge sedimentation tank 6 has a lower half 62 of a cylindrical sedimentation tank main body 61 formed in a mortar shape, and a sedimentation sludge extraction pipe 63 for extracting sedimented sludge is connected to the lowermost part thereof. ing. Further, a floating sludge extraction pipe 64 for discharging scum floating on the liquid surface is connected to the upper side wall of the settling tank main body 61 at substantially the same height as the liquid surface.

As shown in FIG. 3 (b), the floating sludge extraction pipe 64 has a notch 64a cut along a height substantially equal to the liquid level L at a portion facing the settling tank main body 61. It has a gutter shape for receiving scum floating on the liquid surface and discharging it to the outside.

A rotating shaft 65 is disposed vertically in the center of the inside of the sludge settling tank 6, and the upper end thereof is provided with a speed reducer mounted on a gantry 66 provided on the upper part of the sludge settling tank 6. The motor 67 is connected to the motor 67 so that the motor 67 rotates at a reduced speed.

At the lower end of the rotating shaft 65, a plurality of settling sludge scrapers 68 are mounted. Settling sludge scraper 68
The sludge settled to the bottom of the sludge settling tank 6 by the rotation of the rotating shaft 65 is raked to the bottom, and the settled sludge extraction pipe 63
Is formed in a plate shape, and one side in the longitudinal direction has a lower half portion 62 of the sludge settling tank 6.
It is attached to the rotating shaft 65 along the inner surface of the mortar-shaped side wall.

A floating sludge scraper 69 is mounted above the rotating shaft 65. In the floating sludge scraper 69, an appropriate number (two in the illustrated example) of rods 69a extend in a substantially horizontal direction from the rotating shaft 65 at a position slightly above the liquid level.
Blades 69b are respectively provided on the lower surface side of the rod body 69a so as to be partially immersed in the liquid surface. The floating sludge scraper 69 scrapes the scum floating on the liquid surface by the blade 69b with the rotation of the rotating shaft 65 by the motor 67, and the blade 69b comes into contact with the floating sludge extraction pipe 64. Thereby, the scum that has been swept up functions to flow into the floating sludge extraction pipe 64 from the notch portion 64a.

The blade 69b is connected to the floating sludge extraction pipe 64.
Is formed of a flexible member such as rubber, soft synthetic resin, or the like, so that the floating sludge extraction pipe 64 can get over the floating sludge extraction pipe 64 as the rotating shaft 65 rotates. It is also preferable to form the blade 69b by bonding a cloth to the surface of the blade made of rubber or soft synthetic resin or the like. When the blade 69b is configured in this manner, the uneven surface of the cloth holds the scum and floats on the liquid surface. The effect of efficiently scraping the scum and pouring it into the floating sludge extraction pipe 64 from the notch 64a can be effectively exerted.

According to the present invention, even if the sludge oxidized in the pre-reaction means 3 is received in the sludge settling tank 6, the scum generated in the sludge settling tank 6 is removed by the floating sludge scraper 69.
The scum can be prevented from entering the subsequent nitrification and denitrification tank (reaction means 8) because the sludge can be removed from the floating sludge extraction pipe 64 to the outside of the sludge settling tank 6.

The sludge extracted by the settling sludge extraction pipe 63 and the floating sludge extraction pipe 64 is sent to the dewatering means 7 through a sludge pit (not shown).

In the dewatering means 7, a polymer dehydration aid is used. When the sludge properties are stabilized, there is an effect that the amount of the polymer dehydration aid can be reduced.

Furthermore, the dewatered sludge (cake) is an environment in which organic matter is decomposed and sludge in which useful bacteria are predominantly present, so that it is in an environment where spoilage bacteria cannot inhabit.
There is an effect that composting of dewatered sludge can be easily performed, and processing instead of incineration can be easily performed.

Further, in the present invention, since there is a return means 8A for returning the excess sludge generated in the reaction means to the pre-reaction means 3 or the preceding step, the excess sludge is generated by the dehydration and the pre-treatment of the excess sludge. The dewatering of the mixed septic tank sludge can be simultaneously performed, and the cost of the dewatering equipment can be reduced.

The separated liquid separated by the dehydrating means 7 is sent to the reaction means 8 and reprocessed.

The reaction means 8 following the sludge settling tank 6 is mainly constituted by a nitrification denitrification treatment tank, and the constitution of the nitrification denitrification treatment tank is not particularly limited.

In the present invention, the presence of the prereaction means 3 promotes the oxidative decomposition of organic substances, thereby reducing the load of organic substances in the nitrification and denitrification treatment tank, and does not cause an increase in viscosity. Stable processing becomes possible.

When a flocculant containing a silica component is used, a treatment system is formed so that the biota is a dominant species of useful microorganisms or bacteria, so that it is also useful in a nitrification and denitrification treatment tank. Bacteria become the dominant species, the biota is stable, and stable processing is possible.

In addition, since the scum floating on the liquid surface in the sludge settling tank 6 is removed by the function of the floating sludge scraper 69, the scum causing the load fluctuation enters the nitrification denitrification tank. In other words, the processing in the reaction means 8 is performed more stably.

Numeral 9 is 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 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 reaction means 8, and as described above, the treatment in the nitrification and denitrification treatment tank in the reaction means 8 is stable. Thereby, clogging of the film 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 in a tank. 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 8 and a part thereof is returned to the pre-reaction means 3 as described above as excess sludge. You.

The permeate separated by the membrane separation means is further subjected to advanced treatment if necessary. For example, the decolorization treatment is performed in the activated carbon treatment means 10 as shown in the figure, and the treated water is reused or discharged.

In the above description, the sludge settling tank 6
Has been described in terms of a circular shape in plan view composed of a cylindrical sedimentation tank main body 61, but is not limited to this, and may be a rectangular shape in plan view. In this case, the floating sludge extraction pipe is arranged along one side wall, and the floating sludge scraper attached to the rotating conveyor is driven in one direction from the side wall facing the floating sludge extraction pipe toward the floating sludge extraction pipe. Or the floating sludge extraction pipes may be arranged on the opposing side walls, and the floating sludge scraper may be provided so as to reciprocate between the opposing floating sludge extraction pipes.

[0059]

As described above, according to the present invention, floating sludge generated when solid-liquid separation is performed in a sludge sedimentation tank via a pre-reaction means is removed, and the inflow to the subsequent reaction means is prevented. Accordingly, it is possible to eliminate the factor of the load fluctuation in the reaction means, realize a stable treatment, and provide a urine wastewater treatment apparatus.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an example of an embodiment of the present invention.

FIG. 2 is an explanatory view showing an example of a pre-reaction tank.

FIG. 3A is a longitudinal sectional view showing an example of a sludge settling tank,
(B) is a perspective view showing a floating sludge extraction pipe.

[Explanation of symbols]

 1: First pretreatment means 2: Second pretreatment means 3: Prereaction means 4: Addition equipment for coagulant containing iron component 5: Addition equipment for coagulant containing silica component 6: Sludge settling tank 61: Settling tank Main body 62: Lower half 63: Settling sludge removal pipe 64: Floating sludge removal pipe 64a: Notch 65: Rotating shaft 66: Stand 67: Motor 68: Settling sludge scraper 69: Floating sludge scraper 69a: Rod 69b: Blade 7: Dehydration means 8: Reaction means 8A: Return means 9: Solid-liquid separation means 10: Activated carbon treatment means

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C02F 9/00 504 C02F 9/00 504E B01D 21/01 B01D 21/01 A 102 102 21/02 21/02 M C02F 1/52 C02F 1/52 E 1/72 ZAB 1/72 ZABZ 3/34 101 3/34 101B 11/14 11/14 B (71) Applicant 000219314 Toray Engineering Co., Ltd. Nakanoshima, Kita-ku, Osaka-shi, Osaka 3-4-1-18 (Mitsui Building No. 2) (71) Applicant 000004123 Nippon Kokan Co., Ltd. 1-1-2 Marunouchi, Chiyoda-ku, Tokyo (72) Inventor Hitoshi Yano 5-6-1 Tsukiji, Chuo-ku, Tokyo No. Mitsui Engineering & Shipbuilding Engineering Co., Ltd. Environment Division (72) Inventor Satoshi Ogura 8-4-6 Nishikasai, Edogawa-ku, Tokyo ST Nishikasai Bi (72) Inventor Junichi Baba 2-2-33 Kinrakuji-cho, Amagasaki-shi, Hyogo Pref.Takuma Plant Construction Control Headquarters Water Treatment Technology Division 1 (72) Inventor Koji Kawabata Mitsui Engineering & Shipbuilding Co., Ltd. 1-1-1 Sonoyama, Otsu City, Shiga Prefecture Toray Engineering Co., Ltd. Shiga Plant (72) Inventor Toraro Minegishi 1-1 Minamiwata-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Prefecture Water Research Laboratory, Nihon Kokan Co., Ltd. F-term (reference) 4D015 BA04 BA12 BA19 BA24 BA29 BB08 BB16 CA03 CA12 DA13 DA16 DA19 DA22 DA32 DA35 DC02 EA32 FA01 FA02 FA03 FA16 FA17 FA19 FA22 FA24 FA25 FA26 4D040 BB52 DD03 DD14 DD22 4D050 AA15 AA16 AB04 BD24 AB26 BD35 CA04 CA06 CA09 CA15 CA16 CA17 4D059 AA01 AA02 AA03 BE00 BE49 BE56 CA22 CA28 CC01 4D062 BA04 BA12 BA19 BA24 BA29 BB08 BB16 CA03 CA12 DA13 DA16 DA19 DA22 DA32 DA35 DC02 EA32 FA01 FA02 FA03 FA16 FA17 FA19 FA22 FA24 FA25 FA25 FA26

Claims (2)

[Claims] 1. A pre-reaction means comprising a pre-reaction tank for adding a flocculant to sewage wastewater containing human waste and septic tank sludge and oxidizing the waste water, and the wastewater treated by the pre-reaction means is solidified into a supernatant liquid and sludge. Sludge sedimentation tank for liquid separation, dewatering means for dewatering the sludge separated in the sludge sedimentation tank, and reaction means for introducing the supernatant separated in the sludge sedimentation tank and performing nitrification and denitrification treatment. An apparatus for treating human waste water, wherein a floating sludge scraper is installed in the sludge settling tank. 2. An apparatus for treating human waste water according to claim 1, wherein said coagulant comprises two types: a coagulant containing an iron component and a coagulant containing a silica component.