JP2006043556A - Septic tank coping with disposer wastewater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a septic tank coping with disposer wastewater which can be produced into many different kinds at a low cost. <P>SOLUTION: The septic tank coping with disposer wastewater performs treatment of domestic wastewater containing the disposer wastewater by using an underground installed small-scale septic tank. As its outer tank, an outer tank of the above small-scale septic tank corresponding to ≥1.4 and ≤2.0 times the number of men, who are a target of treatment by the septic tank coping with disposer wastewater, is used. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention treats manure, other domestic wastewater, kitchen wastewater, disposer wastewater, etc., or their combined sewage (hereinafter also referred to as sewage), and treats them using an outer tank of a human tank that is larger than the personnel to be treated. It relates to a sewage septic tank.

Since the septic tank has the feature that it can be installed in a short period of time and at a relatively low cost, it is used as a wastewater treatment system that replaces the sewerage system especially in a population scattered area such as an urban suburb or a mountainous area. Among these septic tanks, the one most frequently used is a septic tank having the same treatment performance as general sewage effluent water (hereinafter referred to as BOD) 20 mg / L (hereinafter, popularized). Type). On the other hand, in closed water areas such as lakes and inner bays, and in areas where the septic tank discharge destination is near the tap water source, advanced treatment septic tanks that remove nitrogen and phosphorus in addition to organic substances are used. Recently, disposable septic tanks that dispose of garbage generated in daily life by using a disposer and let it flow into the septic tank for treatment are also on the market, and it will become popular in the future due to its convenience. Is expected.
In general, these septic tanks are produced in factories, and are then transported and buried at the site where the septic tanks are installed, so that the septic tanks are required to have a certain strength and durability. Usually, a resin material such as FRP or dicyclopentadiene is used as the material of the outer tank of the septic tank in consideration of ease of molding in addition to strength and durability. Outer tanks of these septic tanks were manufactured by using a mold necessary for each type of septic tank and a human tank and mass-producing them.
JP 2001-286878 A

However, when the conventional method is used to produce household septic tanks (5, 7, 10-person tanks), for example, three types of popular type (processing performance BOD 20 mg / L), advanced processing type, and disposable type Since there are three types of septic tanks and three differences in human tanks, a total of nine types of molds are required, and the cost burden for manufacturing and maintaining the molds is very large.
It is an object of the present invention to provide a disposable septic tank that can produce many types of septic tanks at low cost.

In order to achieve the above object, the present invention has the following configuration.
(1) The present invention is a disposer drainage-compatible septic tank that treats domestic wastewater including disposer drainage using a buried underground small-scale septic tank. It is a disposer drainage-compatible septic tank using an outer tank of the above-mentioned small-scale septic tank corresponding to 1.4 to 2.0 times the number of personnel.
(2) The present invention is an underground buried type small-scale septic tank, and is a disposer drainage septic tank that treats domestic wastewater including disposer drainage using a small-scale septic tank having a flow rate adjusting function. Is a disposer drainage-compatible septic tank that uses an outer tank of the above-mentioned small-scale septic tank corresponding to more than 1.0 times and 1.5 times or less of the personnel to be treated in the disposer drainable septic tank.
In the item (1) or (2), an aerobic treatment tank is provided in the tank, and the aerobic treatment tank includes an aerobic reaction part and a filtration part. The capacity ratio is 6.5 to 9.0: 3.5 to 1.0.

  According to the present invention, since many types of septic tanks can be manufactured with a small number of molds, it is possible to reduce the cost burden for manufacturing and maintaining the molds.

The small-scale septic tank described in the present invention refers to a septic tank having a processing target personnel (N) of 5 to 50 people.
The number of persons to be treated (N) is a value calculated based on the “Calculation standard for the number of persons to be treated for sewage septic tanks by use of buildings (JIS A 3302-2000)”, and the size of the septic tank is selected. This is the reference value when doing this. For example, when the building usage is a house, if the total area of the building is <130 m ² , N = 5 people, if the total area of the building is ≧ 130 m ² , N = 7 people, a two-family house (kitchen and bath N is 10 or more).
The human tank represents the size of the septic tank for treating the sewage for the target personnel. For example, a five-person septic tank is used for a facility (N) = 5 persons. It is done.
Moreover, an outer tank refers to the outermost tank which forms the septic tank main body.

Next, the disposer and the disposer drain will be described.
The disposer is a garbage crusher that crushes garbage while flowing water and flows it to a drain pipe, and is usually installed under the sink of a sink. Moreover, the liquid containing the pulverized garbage discharged from the disposer is called the disposer drain.
The pollutant concentration of the disposer drainage is set based on the wastewater when the garbage having a composition called “standard garbage” shown in FIG. 1 is pulverized by the disposer. This standard garbage disposer drainage pollutant load concentration and the amount of pollutant load are reported by the Ministry of Construction's Building Research Institute in March 1997 on the “Development of Disposable Garbage Recycling System (1994-1997)” 2 ”and FIG. 3 respectively.

  A small-scale septic tank having a flow rate adjusting function refers to a septic tank having a flow rate adjustment ratio (maximum amount of transferred water per hour / daily average amount of sewage) of 3.0 or less.

Next, an example of an underground buried type small-scale septic tank that can be used in the disposer-drainage septic tank of the present invention will be described with reference to the drawings.
FIG. 4 is a schematic cross-sectional view showing an embodiment of an underground buried type small-scale septic tank. First, the structure will be described. The septic tank includes an anaerobic treatment tank first chamber 21, an anaerobic treatment tank second chamber 22, an aerobic treatment tank 30, a treated water tank (precipitation tank) 40, and a disinfection tank 33.
In FIG. 4, the outer tank has a substantially square cross-sectional shape, but is not particularly limited, and a circular shape, an elliptical shape, or the like can be used. Moreover, although the dicyclopentadiene resin is used as the material of the outer tub, other materials such as FRP may be used.

  The shape of the filter bed 23 provided in the anaerobic treatment tanks 21 and 22 is not particularly limited, and plate-like members such as loofah-like, corrugated and porous, honeycomb-like (honeycomb core) members, etc. Preferably used. Also, skeleton spheres, mesh-like cylindrical members, and the like can be used. The filter bed 23 may be provided only in the anaerobic treatment tank second chamber 22, or may be removed from both the anaerobic treatment tank first chamber 21 and the anaerobic treatment tank second chamber 22.

  The aerobic treatment tank 30 includes a biological reaction chamber 9 in the upper portion and a filtration chamber 10 in the lower portion. In the small-scale septic tank shown in FIG. 4, the biological reaction chamber 9 and the filtration chamber 10 are arranged up and down, but the positional relationship between the two chambers is not limited to this and may be arranged in the horizontal direction. . In addition, an air lift pump 31 for transferring the liquid processed in the aerobic treatment tank 30 to the anaerobic treatment tank first chamber 21 is provided on the downstream side of the aerobic treatment tank 30.

  In the biological reaction chamber 9, a biological reaction bed 9a and a diffuser member 11 for biological reaction are provided below the biological reaction bed 9a. The biological reaction bed 9a is filled with a filter medium (microorganism carrier, microorganism adhesion material, contact material) to which microorganisms for aerobically treating organic substances in the influent are adhered. The biological reaction bed 9a may be a fluidized bed or a fixed bed.

  The shape of the filter medium can be various shapes such as plate, net plate, loofah, porous, cylinder, rod, skeleton sphere, string, and granular, irregular lump, cube, and fiber lump. What was processed can be used. Examples of the base material include synthetic resin processed products such as polyvinyl chloride, polyester, polyvinylidene chloride, polyvinyl formal, polyurethane, and melamine resin, inorganic processed products such as ceramics and silica sand, and fossils such as anthracite. A processed product, activated carbon or the like having a specific gravity of about 1 or 1 or more, a polyolefin resin such as polyethylene or polypropylene, or a specific gravity of about 1 or 1 or less such as polystyrene can be used.

  A filtration bed 10a filled with a filter medium is formed in the filtration chamber 10 to capture and remove SS in the influent. As the filter medium to be filled, one that floats in the liquid can be used, but a sedimentation filter medium is preferable. Examples of sedimentary filter media include synthetic resin processed products such as polyvinyl chloride, polyester, polyvinylidene chloride, polyvinyl formal, polyurethane, and melamine resin, inorganic processed products such as ceramics and quartz sand, and fossil processing such as anthracite. Products, activated carbon, etc., with specific gravity of about 1 or more, or polyolefin resin such as polyethylene, polypropylene, etc., and those with a specific gravity of about 1 or more adjusted by adding fillers to polystyrene. It may be formed and processed into a lump shape, a cylindrical shape, a net shape, a rod shape, a fiber lump shape, or a porous shape.

  Below the filter bed 10a, a cleaning air diffuser 12 for cleaning the filter bed 10a is arranged, and this is connected to a blower 35 for supplying air. Further, a cleaning drainage pump 14 is provided for transferring the cleaning drainage 4 generated when the SS captured by the filtration bed 10 a is peeled off to the anaerobic treatment tank first chamber 21.

  When the disposer drainage is caused to flow into such a small-scale septic tank, as shown in FIG. 3, the pollutant load amount corresponding to the BOD load amount of 27.5 g / (person / day) increases. Since the BOD load of a normal septic tank is 40 g / (person / day), the BOD load increases by (40 + 27.5) /40=1.69 times due to the inflow of the disposer drainage.

  For this reason, when the human tank of a small-scale septic tank is applied as it is to the disposer drainage-type septic tank, it is difficult to ensure the desired processing performance of the small-scale septic tank. Therefore, as a result of intensive investigations on the conditions for applying the outer tank of this small-scale septic tank to a disposable septic tank, it is 1.4 to 2.0 times the number of personnel subject to the disposal septic tank. The conclusion was reached that the desired treatment performance could be secured if an outer tank of the corresponding small-scale septic tank was used. The details will be described below.

In order to apply the outer tank of the small-scale septic tank to the septic tank for disposer drainage, the increase in the tank capacity required to cope with the increase in the pollution load due to the inflow of the disposer drainage was examined for each unit.
First, the anaerobic treatment tank will be described. The functions required for an anaerobic treatment tank are (A) storage of sludge generated in one year, (B) separation of inflowing solids, (C) denitrification of nitrite nitrogen and nitrate nitrogen, and the like. Among these, for (B), even if the disposer drainage flows, the water load that affects the solid-liquid separation function only increases by 1.025 times. Has little effect on As for (C), the BOD / N ratio (ratio of the inflow BOD amount to the inflow nitrogen amount), which is an important factor for ensuring the denitrification performance due to the inflow of the disposer drainage, is about 4.4 to about Since it increases to 6.5, it is advantageous. Therefore, among these, in calculating the required capacity of the anaerobic treatment tank 20, the most important factor is the sludge storage function (A).
FIG. 5 shows the results of studying the sludge storage status in the anaerobic treatment tank when the disposer drainage was introduced and when the disposer drainage was not introduced. FIG. 5 shows the results of measurement after the sludge storage status with and without disposer drainage was passed for one year. From FIG. 5, the sludge conversion rate (generated SS amount / removed BOD amount) when disposer wastewater is put in a general septic tank is 0.45, and sludge conversion rate 0.44 when disposer wastewater does not flow in. The results are almost the same as Accordingly, the generated sludge weight increases in proportion to the increase in the BOD load amount of the disposer drainage. On the other hand, in terms of sludge capacity, when disposer wastewater is introduced, sludge rises to the upper part of the anaerobic treatment tank and becomes easy to concentrate as scum, resulting in an increase in sludge storage capacity due to the addition of the disposer wastewater. The minute was found to be about 1.2 times.
Therefore, the anaerobic treatment tank of the disposer septic tank can store sludge for one year by setting the capacity to 1.2 times or more of the anaerobic treatment tank of the small-scale septic tank, ensuring the treatment function required for the anaerobic treatment tank. it can.

Next, the aerobic treatment tank will be described. The functions required for the aerobic treatment tank 30 are (A) oxidative decomposition of BOD components, (B) nitrification of ammonia nitrogen to nitrate nitrogen (in the case of advanced treatment septic tank), etc. Is added to this by filtration separation of the (C) SS component.
As shown in FIG. 3, the increase in the BOD load when the disposer wastewater flows is 1.69 times. However, as shown in FIG. 2, most of the BOD components of the disposer wastewater are non-soluble BOD, such as non-soluble BOD 4,200 mg / L and soluble BOD 1,300 mg / L. Most of the non-soluble BOD is removed by trapping on the filter bed of the anaerobic treatment tank or sedimenting at the bottom of the tank, or floating and separating as a scum, and only a part of the removed non-soluble BOD is removed for a time. It gradually elutes over time. According to our examination results, the BOD concentration of the inflow water to the aerobic treatment tank when the disposer wastewater is introduced is about 40 mg / L, which is compared with the BOD concentration of 30 mg / L without the disposer wastewater inflow. And it has increased only about 1.33 times. Therefore, even when this elution is taken into account, the increase in the BOD load due to the inflow of the disposer drainage is about 1.33 times.
Therefore, the capacity of the aerobic treatment tank necessary to cope with the inflow of the disposer wastewater may be about 1.33 times the necessary capacity of the small-scale septic tank into which the disposer wastewater does not flow.
Further, since the increase in the TN component due to the inflow of the disposer drainage is about 1.16 times from FIG. 3, the same applies to the case where the nitrogen component is removed by the inflow of the disposer drainage.
In addition, the surface area of the filter medium filled in the aerobic treatment tank is increased to increase the amount of microorganisms in the tank, the amount of air sent to the aerobic treatment tank is increased, or a flow adjustment function is added to the front stage of the aerobic treatment tank 30 By doing so, a more stable treated water quality can be obtained, and the capacity of the aerobic treatment tank can be further reduced.

Although the function calculated | required by a treated water tank (precipitation tank) is mainly storage of treated water, when setting it as a precipitation tank, the solid-liquid separation function of the SS component produced | generated by the aerobic treatment tank is calculated | required. The solid-liquid separation function of the treated water tank (precipitation tank) usually has a water area load (load of the amount of water flowing in per horizontal cross-sectional area of the precipitation tank), an overflow weir load (weir when discharged from the precipitation tank) It is evaluated by water load such as load of water against length).
From FIG. 3, the increase in the water load when the disposer wastewater flows is 1.025 times. Therefore, in order to ensure the solid-liquid separation function when the disposer wastewater flows, the treated water tank (precipitation tank) The horizontal cross-sectional area and the length of the overflow weir may be increased by 1.025 times.

  Regarding the disinfection tank, according to the Ministry of Construction Notification No. 1292 “Structural Standards for Manure Septic Tank”, the capacity of the disinfection tank to ensure the prescribed disinfection function shall be a capacity that will be a residence time of 15 minutes or more. It is written. Since the increase in the water amount load when the disposer drainage flows is 1.025 times, in order to secure the disinfection function in this case, the capacity of the disinfection tank may be increased by 1.025 times.

In summary, the condition of each unit to cope with the increase in pollution load due to the inflow of the disposer wastewater is 1.2 times higher in the anaerobic treatment tank than in the small-scale septic tank where the disposer wastewater does not flow in. The treatment tank only needs to have a capacity of 1.33 times and the disinfection tank 33 needs to have a capacity of 1.025 times. With respect to the treatment water tank (precipitation tank), in order to secure the solid-liquid separation function, the treatment water tank (precipitation tank) ) Horizontal cross-sectional area and the length of the overflow weir may be 1.025 times.
Therefore, when using an outer tank of a small-scale septic tank as a disposer drainage-compatible septic tank, if an outer tank of a small-scale septic tank is used that is at least 1.4 times the target personnel of the disposer drainable septic tank, Expected performance can be obtained. More specifically, as the 5-person tank, 7-person tank, and 10-person tank of the disposer drainage-compatible septic tank, a 7-person tank, 10-person tank, and 14-person tank or more outer tank may be used. However, if a very large outer tub is used, the installation area of the septic tank becomes large, the workability deteriorates, and the cost of the septic tank itself increases. Accordingly, it is preferable to use an outer tank of a human tank of a small-scale septic tank that is 2.0 times or less of the personnel to be treated in the disposer-drainage septic tank, and more preferably 1.8 times or less.
In addition, when applying the outer tank of a small-scale septic tank to a disposer drainage-compatible septic tank, it may be used as it is without changing the internal specifications.For example, the position of the partition plate that divides each unit device, the filter medium Change the type, filling amount, position of the diffusing tube for supplying air to the aerobic treatment tank, the amount of air, etc., add inflow baffles, baffle plates and flow rate adjustment functions, or send air to the aerobic treatment tank The processing function of each unit device can be further enhanced by changing internal specifications such as mixing ozone.

  Next, with reference to the drawings, an embodiment of a small-scale septic tank having a flow rate adjusting function that can be used in the disposer drainage septic tank of the present invention will be described. FIG. 6 is a schematic sectional view showing one embodiment of a small-scale septic tank having a flow rate adjusting function. First, the structure will be described. The small-scale septic tank includes an anaerobic treatment tank first chamber 21, an anaerobic treatment tank second chamber 22, an aerobic treatment tank 30, a treated water tank (precipitation tank) 40, and a disinfection tank 33. The flow rate adjusting unit 3 is provided in the upper part of the anaerobic treatment tank first chamber 21, and the flow rate adjusting device 7 is provided in the advection part 13 of the anaerobic treatment tank first chamber 21.

  Here, the anaerobic treatment tanks 21 and 22, the aerobic treatment tank 30, the treated water tank (precipitation tank) 40, and the disinfection tank 33 are the same as those described in FIG.

In FIG. 6, the flow rate adjusting unit 3 is an L.A. W. L to H. W. Although it is provided between L, you may provide over both chambers of the anaerobic processing tank 1st chamber 21 and the anaerobic processing tank 2nd chamber 22.
The flow rate adjusting device 7 is an L.L. W. A pump 5 for pumping the liquid in the tank from the suction port 8 provided at the liquid level L, and a part of the pumped liquid connected to the pump 5 is transferred to the second chamber 22 for the anaerobic tank. And a water amount adjusting device 6 for returning the surplus liquid into the advection section 13.
The water level in the first chamber 21 of the anaerobic treatment tank rises when the inflow amount of sewage is larger than the liquid feed amount of the pump 5, and falls when the amount is small. W. L and H.H. W. Move up and down with L. At this time, the capacity of the flow rate adjusting unit 3 is determined according to the inflow of sewage. W. L is set so as not to exceed L.
In FIG. 6, the pumping pump 5 is an air lift pump type, but an intermittent metering pump or an electric pump by pneumatic feeding of a sealed container may be used instead of the air lift pump type. In addition, the water volume adjusting device 6 is a system that distributes the pumped liquid by adjusting the weir height, a system that distributes using the orifice, a system that adjusts the pumped water volume by adjusting the air volume using a valve, etc. However, the weir height adjustment method is preferable because the liquid flow rate can be easily adjusted.

In the septic tank having the flow rate adjusting function as described above, the flow rate adjustment unit 3 can absorb the fluctuation in the amount of influent sewage, so that the solid separation performance in the anaerobic treatment tank 20 and the treated water tank (precipitation tank) 40 is improved. Can greatly increase. Moreover, since only the amount of water below a certain flow rate can be sent in the aerobic treatment tank 30, the possibility that the liquid in the anaerobic treatment tank 20 will flow in a short time and the quality of the treated water will deteriorate is reduced, and a stable treated water quality is obtained. It becomes possible.
Therefore, in the septic tank having the flow rate adjusting function, the influence on each unit device due to the inflow of the disposer waste water can be extremely low, and as a result, stable treated water quality can be obtained without increasing the capacity so much. Become.
For this reason, when using an outer tank of a small-scale septic tank that has a flow rate adjusting function for the disposable septic tank, it is more than 1.0 times less than the target personnel of the disposable septic tank and 1.5 times or less. The desired performance can be obtained by using the outer tank of the human tank of the scale septic tank. In this case, the capacity of the aerobic treatment tank 30 is increased by changing or removing the position of the partition plate separating each unit device, the surface area of the filter medium of the aerobic treatment tank 30 is increased, If the amount of air to be supplied to the gas treatment tank 30 is increased, a more stable treated water quality can be obtained.

  As shown in FIGS. 4 and 6, when the aerobic treatment tank 30 has the biological reaction chamber 9 and the filtration unit 10, the volume ratio between the biological reaction chamber 9 and the filtration unit 10 is set to 6.5 to 9. It is preferably set to 0.0: 3.5 to 1.0, more preferably 7.5 to 8.5: 2.5 to 1.5. With such a volume ratio, the aerobic treatment function of the entire aerobic treatment tank 30 can be maximized while ensuring the filtration function in the filtration unit 10, so that stable treated water quality can be obtained.

  Hereinafter, the sewage treatment will be described with reference to FIG. The sewage containing the disposer drainage enters the anaerobic treatment tank first chamber 21 from the sewage inflow port 2, and the solid matter in the influent sewage is separated and anaerobic treatment is performed. The advection liquid from the anaerobic treatment tank first chamber 21 enters the anaerobic treatment tank second chamber 22 where further solids separation and anaerobic treatment are performed.

  The advection liquid from the anaerobic treatment tank second chamber 22 enters the aerobic treatment tank 30, and in the biological reaction chamber 9, the organic matter in the advection liquid from the anaerobic treatment tank second chamber 22 is aerobically biodegraded and generated. The collected SS is captured and filtered in the filtration chamber 10.

  The filter bed 10a is clogged due to accumulation of SS over time, and is thus periodically or appropriately (reversely) washed. In this cleaning, the air in the blower 35 is discharged from the cleaning air diffuser 12 to bubble the filter bed 10a, and a part of the air in the blower 35 is also supplied to the cleaning drainage pump (air lift pump) 14. The peeled SS becomes cleaning wastewater together with the liquid in the tank, descends the filtration bed 10a, returns to the first chamber 21 of the anaerobic processing tank through the cleaning drainage discharge member 14a by the cleaning drainage pump 14. Cleaning of the filter bed 10a is usually preferably performed at midnight when sewage is rarely discharged in a general household. The advection liquid from the aerobic treatment tank 30 passes through the treatment water tank 40, enters the disinfection tank 33, is in contact with the medicine cylinder 38 and is sterilized, and is then discharged from the outlet as treated water.

The standard garbage wet weight list is shown. Indicates the pollutant load concentration of the disposer drain. Indicates the pollutant load of the disposer drain. It is a schematic sectional drawing which shows an example of the small-scale septic tank which can be used for the disposable effluent corresponding | compatible septic tank which is the Example of this invention. The result of having measured the sludge storage condition by the presence or absence of the disposer drainage after having passed for one year is shown. It is a schematic sectional drawing which shows an example of the small-scale septic tank which has a flow volume adjustment function which can be used for the disposable effluent corresponding | compatible septic tank which is the other Example of this invention.

Explanation of symbols

2 ... sewage inlet, 3 ... flow rate adjustment unit, 4 ... washing drainage, 5 ... pumping pump, 6 ... water volume adjustment device, 7 ... flow rate adjustment device, 8 ... suction port, 9 ... biological reaction chamber, 9a ... biological reaction bed DESCRIPTION OF SYMBOLS 10 ... Filtration chamber, 10a ... Filtration bed, 11 ... Aeration member, 12 ... Cleaning aeration member, 13 ... Advection part, 14 ... Washing drain drawing pump, 14a ... Washing drain discharge member, 20 ... Anaerobic treatment tank, 21 ... Anaerobic treatment tank 1st chamber, 22 ... Anaerobic treatment tank 2nd chamber, 23 ... Filter bed, 30 ... Aerobic treatment tank, 31 ... Air lift pump, 33 ... Disinfection tank, 35 ... Blower, 38 ... Medicine bottle, 39 ... manhole, 40 ... treated water tank

Claims (3)

  Disposer drainage-compatible septic tank that uses a buried underground small-scale septic tank to treat domestic wastewater including disposer drainage, and this outer tank is 1.4 times more than the target personnel of the disposer drainable septic tank Disposer drainage type septic tank using an outer tank of the above-mentioned small septic tank corresponding to 2.0 times or less.   Disposer drainage type septic tank that is a subsurface buried type small septic tank that treats domestic wastewater including disposer drainage using a small septic tank that has a flow control function. Disposer drainage type septic tank using an outer tank of the above-mentioned small-scale septic tank corresponding to 1.0 to 1.5 times the number of personnel to be treated. In Claim 1 or 2, an aerobic treatment tank is provided in a tank, this aerobic treatment tank has an aerobic reaction part and a filtration part, and the volume ratio of an aerobic reaction part and a filtration part is It is 6.5-9.0: 3.5-1.0, The septic tank characterized by the above-mentioned.

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