Septic tank treated water recirculation system

Abstract

The purpose is to promote the efficient use of water resources and to provide a wastewater recirculation system that allows toilets to be used even when the supply of tap water is interrupted during droughts or disasters. [Solution] The septic tank treated water recirculation system 100 comprises a septic tank 1 in which an anaerobic first tank 11, an anaerobic second tank 12 located downstream of the first tank 11, and an aerobic third tank 13 and a disinfection tank located downstream of the second tank 12 are connected in series in this order; a recirculation tank 2 for storing treated water treated in the third tank 13; and a supply means for supplying the treated water in the recirculation tank 2 to non-drinking water facilities 5. The recirculation tank 2 is set to have a capacity greater than or equal to the amount of water used by the water facilities 5 for a predetermined period during a water outage.

Description

Technical Field

[0001] The present invention relates to a treated water circulation system that circulates treated water obtained by purifying domestic wastewater using a septic tank.

Background Art

[0002] 2]Conventionally, septic tanks for purifying sewage such as human waste and domestic miscellaneous wastewater discharged from households and the like are known. For example, Patent Document 1 discloses a water treatment apparatus that purifies the wastewater of ordinary households step by step in a plurality of tanks. This apparatus includes a first anaerobic filter bed tank and a second anaerobic filter bed tank that decompose organic substances in the sewage by anaerobic microorganisms attached to filter media, and a carrier flow biological filtration tank that flows a carrier to which aerobic microorganisms are attached and aerobically decomposes organic substances.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The water treatment apparatus described in Patent Document 1 includes a phosphorus removal apparatus that supplies ions from a metal electrode to remove phosphorus components, an air diffusing and backwashing apparatus that supplies oxygen and cleans the carrier by supplying air from a blower, a treatment water tank that temporarily stores the treated water and circulates a part of it upstream (the first anaerobic filter bed tank), a disinfection tank that injects a chemical to treat the water hygienically, and a discharge pump tank that stores the purified water and pumps it out to the outside. Then, the treated water is finally discharged to the outside such as a river by a pump.

[0005] Thus, in conventional household septic tanks, treated water was discharged into rivers and other bodies of water, and this treated water was not reused. As a result, tap water was used for toilet flushing and other purposes, leading to the problem of insufficient and effective utilization of water resources. In recent years, rising tap water rates and the need for more efficient use of water resources have become increasingly important.

[0006] Furthermore, if the water supply is interrupted during droughts or disasters, there is a problem in that water-related facilities such as toilets become unusable. Maintaining essential living functions is especially important now that the risk of water outages due to earthquakes and heavy rains is becoming more apparent. For example, in the event of a water outage due to a disaster, it may be possible to tolerate restrictions on the use of baths and washbasins for a certain period, but toilets are essential for daily life, and even a short period of unusability is a serious problem. Toilets in evacuation centers become crowded with many evacuees, raising concerns about deteriorating sanitary conditions.

[0007] This invention was made in view of these problems, and aims to provide a wastewater recirculation system for septic tanks that can effectively utilize water resources. [Means for solving the problem]

[0008] To solve the above problems, a septic tank treated water recirculation system according to one aspect of the present invention comprises a septic tank in which an anaerobic first tank, an anaerobic second tank located downstream of the first tank, and an aerobic third tank located downstream of the second tank are connected in series in this order; a recirculation tank for storing treated water treated in the third tank; and a supply means for supplying the treated water in the recirculation tank to non-drinking water facilities.

[0009] The aforementioned circulation tank may be set to a capacity equal to or greater than the amount of water used by the water supply equipment for a predetermined period during a water outage. [Effects of the Invention]

[0010] According to this invention, by reusing treated water from a septic tank for use in plumbing facilities, the amount of tap water used can be reduced, thereby promoting the effective use of water resources.

[0011] Furthermore, by setting the circulation tank to a capacity greater than the predetermined limit, it is possible to keep water-related facilities such as toilets usable for a certain period of time even if the supply of tap water is interrupted during a disaster. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic diagram showing the overall configuration of the treated water recirculation system of the present invention. [Figure 2] This figure shows an example of the ratio of wastewater volume from plumbing fixtures. [Modes for carrying out the invention]

[0013] The present invention will be described below with reference to the drawings, based on preferred embodiments. In the embodiments and modifications, the same or equivalent components and members will be denoted by the same reference numerals, and redundant explanations will be omitted as appropriate. In addition, the dimensions of the members in each drawing will be enlarged or reduced as appropriate to facilitate understanding. Furthermore, some members that are not important for explaining the embodiments will be omitted from the drawings.

[0014] Furthermore, while terms including ordinal numbers such as "first" and "second" are used to describe various components, these terms are used solely to distinguish one component from others, and do not limit the components themselves.

[0015] [Embodiment] The embodiments of the present invention will be described below with reference to Figures 1 and 2. Figure 1 is a schematic diagram showing the overall configuration of the septic tank treated water circulation system 100 according to the embodiment. In this figure, the arrows indicate the flow of water such as tap water, wastewater, and treated water.

[0016] Figure 2 shows an example of the ratio of water usage for plumbing fixtures. As shown in Figure 2, the wastewater from household plumbing fixtures is 40% from the bath, 25% from the toilet, 20% from the kitchen / washroom, and 15% from laundry and other uses. Significant water savings can be achieved by circulating and reusing treated wastewater from the toilet alone. This invention achieves significant water savings by circulating treated wastewater.

[0017] As shown in Figure 1, the septic tank treated water recirculation system 100 of the present invention comprises a septic tank 1, a recirculation tank 2, supply piping 3, a supply pump 4, and water supply equipment 5. It may also be equipped with a photocatalytic water purification device 8. The septic tank 1 is configured with an anaerobic first tank 11, an anaerobic second tank 12, and an aerobic third tank 13 connected in series in this order.

[0018] The first tank 11 removes suspended solids from the wastewater using filter media and purifies the wastewater by decomposing organic matter through the action of anaerobic microorganisms that do not require oxygen. The second tank 12 removes fine suspended solids from the wastewater treated in the first tank 11 using finer filter media and further purifies the wastewater by decomposing organic matter through the action of anaerobic microorganisms. The third tank 13 aerates and circulates the wastewater using air supplied by an air pump (not shown) and further purifies the wastewater by decomposing organic matter through the action of aerobic microorganisms attached to the contact material. The above-described configuration of the first, second, and third tanks has been described as a septic tank 1, but this configuration is just one example, and any septic tank used for household wastewater treatment can be used as desired.

[0019] The treated water purified in the third tank 13 further flows into a disinfection tank provided by a partition in the downstream part of the third tank 13. The water that enters the disinfection tank flows out to the circulation tank 2 and is stored in the circulation tank 2. In the present invention, the treated water that was normally discharged from the septic tank 1 can be temporarily stored by further providing a circulation tank 2 downstream of the septic tank 1. The treated water stored in the circulation tank 2 is further purified by the action of naturally occurring bacteria and the like. A supply pipe 3 and a supply pump 4 are connected to the circulation tank 2, and the treated water is supplied to the plumbing facilities 5. Note that the treated water stored in the circulation tank 2 exceeding a predetermined amount is discharged to the outside.

[0020] The plumbing facilities 5 include a water supply side plumbing facility 51 and a circulation side plumbing facility 52. The water supply side plumbing facility 51 is a facility that uses the water supply supplied from the water supply pipe to generate drainage and supplies the drainage to the septic tank 1. Examples of the water supply side plumbing facility 51 include a kitchen sink, a bathtub, a washing machine, and a washbasin.

[0021] The circulation side plumbing facility 52 is a facility that receives the supply of treated water from the circulation tank 2 via the supply pipe 3 and the supply pump 4. The circulation side plumbing facility 52 includes at least a toilet. Also, depending on the sanitary condition of the treated water, it is possible to supply it as non-potable water for washing etc. by changing the piping connection.

[0022] When configured to switch the supply of the water supply from the water supply pipe and the circulated treated water to the circulation side plumbing facility 52, it is necessary to change the piping so that the circulated treated water does not flow back into the water supply side pipe.

[0023] The capacity C2 of the circulation tank 2 is set to a capacity that enables the plumbing facilities 5 to be used for a predetermined period during a water cut-off. For example, it can be set based on the water consumption for one day or more and three days or less during normal times. The capacity C2 can be calculated, for example, by Equation 1. Note that the capacity C2 may be obtained by multiplying the calculation result of Equation 1 by a safety factor. Capacity C2 = (Number of household members × Average washing water volume per person × Assumed water cut-off days) ··· (Equation 1)

[0024] The supply pump 4 can be configured to be driven manually even during a power outage. For example, it may include configurations that allow for power storage using solar panels, emergency response using a portable generator, or driving the pump by hand or foot. In this case, the treated water can be circulated using electricity when there is no power outage, and can also be circulated during a power outage.

[0025] A photocatalytic water purification device 8 can be installed in the middle of the supply piping 3. The photocatalytic water purification device 8 generates reactive oxygen species with strong oxidizing properties by irradiating a photocatalytic material such as titanium dioxide with ultraviolet light or sunlight, thereby decomposing or inactivating organic matter, bacteria, or viruses contained in the supply water. This improves the hygiene of the supply water. As a result, the range of equipment that can be applied as circulation-side water supply equipment 52 can be expanded.

[0026] According to this invention, treated water purified in the septic tank 1 can be supplied to the water supply facilities 5, thereby reducing the amount of tap water used.

[0027] Furthermore, since flushing large amounts of water down the toilet does not affect water bills, it is possible to reduce problems such as blockages in drain pipes that can occur in water-saving toilets. In addition, by setting the capacity of the circulation tank 2 to a predetermined capacity or higher, toilets and other facilities can be used for a certain period even in the event of a water outage during a disaster. Moreover, if the sanitary management technology for circulating treated water improves, it will be possible to use the circulating treated water for non-potable water purposes such as laundry.

[0028] Furthermore, the photocatalytic water purification device 8 can improve the hygiene of the supplied water.

[0029] In the description of the embodiment, an example was shown in which the septic tank 1 is composed of three tanks, but the present invention is not limited to this. The septic tank 1 may further be equipped with other treatment devices or treatment tanks, such as a phosphorus removal device. The septic tank treated water recirculation system of the present invention can be used for wastewater treatment in ordinary households. If an existing septic tank 1 is already in place, the septic tank treated water recirculation system of the present invention can be configured by installing the recirculation tank 2 downstream of the existing septic tank 1. [Explanation of Symbols]

[0030] 1. Septic tank, 11. Tank 1 (anaerobic), 12. Second tank (anaerobic), 13 Tank 3 (aerobic), 2 reflux tank, 3. Supply piping, 4. Supply pump, 5. Plumbing fixtures, 8. Photocatalytic water purification device, 100 Septic tank treated water recirculation system

Claims

1. A septic tank that receives wastewater from plumbing fixtures, A circulation tank for storing treated water that has been purified in the aforementioned septic tank, A supply pipe and supply pump for supplying treated water from the aforementioned circulation tank to non-drinking water facilities. A wastewater recirculation system for septic tanks, characterized by having the following features.

2. The septic tank treatment water circulation system according to claim 1, characterized in that the septic tank comprises an anaerobic first tank, an anaerobic second tank located downstream of the first tank, an aerobic third tank located downstream of the second tank, and a disinfection tank, all connected in series in this order.

3. The wastewater treatment tank recirculation system according to claim 1, wherein the recirculation tank is set to have a capacity equal to or greater than the amount of water used by the water supply equipment for one to three days under normal circumstances.

4. The supply pump is configured to be able to supply treated water manually even during a power outage. The wastewater recirculation system for a septic tank according to claim 1.

5. The wastewater treatment tank recirculation system according to claim 1, wherein a photocatalytic water purification device is provided in the path that supplies the treated water in the recirculation tank to the water supply equipment.

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