JP2011140857A - Rainwater utilization system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a novel rainwater utilization system allowing rainwater fallen in an area, to be effectively utilized in the whole area. <P>SOLUTION: The problem is solved by a water supply system including piping for utilizing water in individual rainwater tanks as water for irrigation, water for washing cars, or the like in each house, water collecting piping for leading water overflowing from a plurality of individual rainwater tanks and water in the rainwater tanks to a storage tank, and a water treatment apparatus for purifying the water in the storage tank, and supplying the purified water as reclaimed water or potable water to each house or to a peripheral area. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a system that uses rainwater as middle water or drinking water.

Various methods of collecting rainwater and using it for irrigation water have been developed.
For example, Patent Document 1 has developed a system that can store rainwater that has fallen on a roof or the like in a water collection pit provided underground from a gutter and send it to a rainwater tank using a submersible pump provided in the water collection pit. Has been. Rainwater that exceeds the capacity of the pump flows into the conventional rainwater treatment system.

  Patent Document 2 discloses a rainwater utilization system that connects and purifies a rainwater extraction path in the middle of a water discharge path for collecting and discharging rainwater that falls in a wide area such as a park.

  Patent Document 3 discloses a rainwater recovery processing device that collects rainwater that has fallen on a roof or the like, drops it in a lower water tank, and purifies it.

  Further, Patent Document 4 discloses a composite apparatus that collects rainwater from each house and supplies waste water generated in the area in combination with middle water and hot water that is heated.

  Patent Document 5 discloses an apparatus that collects and purifies rainwater, rivers, ponds, domestic wastewater, and the like to produce intermediate water or clean water.

Australian Patent Application No. 2007231812A1 JP-A-2005-350867 JP-A-10-216734 JP 2002-206765 A JP-A-9-23496

  Conventional rainwater use is an individual use and cannot be used completely effectively. In other words, the volume of the rainwater tank provided in each house is generally small, and when a large amount of rain falls at once, most of the rainwater is discharged and the rainwater is not effectively used. In particular, in order to use rainwater for clean water, a high degree of purification treatment is required, and it has not been carried out as a heavy burden to perform individually in each house.

  On the other hand, Patent Document 4 shows that rainwater collected at each house is collected in a rainwater basin of the management center and used as middle water, but this is simply provided with a pipe and collected in the rainwater basin. This corresponds to the conventional sewerage system and is costly.

  An object of the present invention is to solve these problems and provide a novel rainwater utilization system capable of effectively utilizing rainwater that has fallen in the region as a whole region.

  The present invention has been made to solve the above-mentioned problems, and a part of rainwater collected at each house is used for irrigation water, and the remaining rainwater and overflowed rainwater can be collected and effectively used as an entire area. Water supply system,

  The system includes a middle water production device and / or clean water production device, and provides a system capable of supplying both middle water and / or clean water according to local needs.

  That is, according to the present invention, piping for using the internal water of individual rainwater tanks for irrigation water, car wash water, etc. is provided at each door, and overflow water (and / or) rainwater tank water is stored in a plurality of individual rainwater tanks. A water supply system for supplying water to the tank, providing a water treatment device for purifying the water in the storage tank, and supplying the purified water to each door or surrounding area as intermediate water and / or drinking water, and the system The small processing apparatus provides a water supply system having a middle water production apparatus and a clean water production apparatus for further purifying it.

  According to the present invention, rainwater can be used as it is for irrigation water, car wash, etc., and water used for drinking water, etc., and middle water used for washing, toilets, etc. are concentrated by concentrating rainwater. Since it can be purified well, rainwater can be efficiently and effectively used as a whole. In particular, in the case of torrential rains such as guerrilla rains that frequently occur in recent years due to climate change, even if there is rainfall that exceeds the capacity of individual tanks, it exceeds the capacity of individual tanks, and so far it has been used for rainwater treatment. Effective use of rainwater that has been made becomes possible. In addition, safe water is supplied. In addition, since irrigation water that does not require purification is not purified, the purification cost can be reduced.

It is an example of the systematic diagram explaining the rainwater utilization system of this invention. It is the figure which showed an example of the flow which performs a middle water process and a clean water process with the water treatment apparatus.

  The rainwater collecting method performed individually is not particularly limited if there is a rainwater tank, but it can be used if there is an existing tank that collects and stores water from the roof etc. in that it does not place a burden on each house. If there is a means to collect from other than the roof, it can be used, or a new water collecting means can be installed. Further, the number of rainwater tanks is not limited to one per household, and a plurality of rainwater tanks may be provided. Conversely, a single rainwater tank may be shared by a plurality of detached houses.

  The volume of the rainwater tank provided individually varies greatly according to the water collection area, annual precipitation, rainfall pattern, etc., but is usually about 1 to 10 KL. The structure of the rainwater tank may be sealed, but for inspection and cleaning purposes, it should be open, and a lid should be provided to prevent dust and the like from being removed between the rain gutter and the rainwater tank. It is preferable to provide strainers and filters, and it is also preferable to provide a device for removing water containing a large amount of turbid components called first flush at the beginning of rainfall. If a rainwater tank is already installed, it is desirable to use it.

  The rainwater tank is connected with piping used for private use such as irrigation water and car washing, and water collection piping for guiding water to the local storage tank. Although it is preferable to provide a pump used for these water guides, it is also possible to use a natural flow due to gravity by installing a rainwater tank at a certain height on a ground tank. In particular, when the rainwater tank is located on a hilltop house, natural flow can be easily used. It is common to install pumps for supplying irrigation water, pipes used for private use such as car wash, etc. It is not necessary to provide a pump. When it is difficult to conduct water at different elevations, a pump for water conveyance can be provided, or a pump used for water supply to piping used for private use such as irrigation water and car washing can be switched and used.

  The volume of the storage tank that collects the overflow water of the rainwater tank is not particularly limited, but an appropriate scale is selected according to the roof area, rainfall, rainfall pattern, number of users, purpose of use (use), demand, and the like. Usually, it is about 100KL-50ML. A plurality of tanks can be provided according to the size of the area, etc., and a relay tank can be provided for primary water collection and sent to the storage tank.

  The rainwater tank can be equipped with a sensor so that the pump can be activated when the water level in the tank reaches a certain level or more. Good.

  The water treatment device for purifying the water collected in the storage tank is selected depending on whether the purified water is used as clean water or middle water. As an example in the case of using it for clean water, it is filtered through a microfilter (MF) membrane or an ultrafiltration (UF) membrane, sterilized with chlorine, and then sent to the waterworks. The quality of the inflow water to the water treatment system is affected by the material of the roof, the tank, and the regional characteristics (such as dust that accumulates on the roof and the water quality of the rainwater itself), and the water quality standards when using it as water supply are also regional. Therefore, it is necessary to select an optimal method for the treatment process according to the influent water quality and the required treatment water quality. In addition to filtration and sterilization using the MF membrane and UF membrane described above, coagulation treatment, precipitation treatment, pH adjustment, ion exchange, reverse osmosis membrane method, ozone treatment method, ultraviolet irradiation method, activated carbon adsorption method, etc. are used in appropriate combinations. . On the other hand, even when used as intermediate water, it is necessary to select an optimal method for the treatment process according to the influent water quality and the required treatment water quality. Usually, the purpose of using middle water is toilet water and irrigation water, so the required water quality is not so severe. Filtration with MF membrane and chlorine sterilization can satisfy the required water quality in most cases. In addition, aggregation treatment, precipitation treatment, pH adjustment, ion exchange, reverse osmosis membrane method, ozone treatment method, ultraviolet irradiation method, activated carbon adsorption method and the like are used in appropriate combination.

In the water treatment apparatus, the significance of producing clean water and middle water is as follows.
That is, water is currently used for beverages, cooking, dishwashing, washing, toilets, and irrigation. Therefore, if it is assumed that the same amount of water is supplied as clean water or intermediate water, the effect of reducing the amount of use of clean water that has been used up to now is the same no matter which one is supplied. If the water consumption reduction effect is the same, it is better to supply low-quality toilet and irrigation water that can be made at low cost, except when there are plenty of resources. Therefore, it is preferable to treat the collected rainwater as it is in the middle water standard and to supply a part of it as drinking water after advanced processing. Therefore, as a concrete method to optimize the production ratio (each treatment amount) of toilets, irrigation water (medium water) and kitchens, water heaters, baths, etc. (water supply) and minimize the amount of tap water used or total cost, rainwater Reservoir volume, Reservoir volume Reservoir volume, Reservoir capacity, Recycler capacity, Recycler capacity, Recycled water (toilet, etc.) consumption (current location, predicted value), Recycled water (kitchen, etc.) Amount (current location, predicted value) Necessary information is extracted from information such as rainfall forecasts and optimized.

  A schematic concept of a rainwater utilization system according to an embodiment of the present invention is shown in FIG.

  As shown in the figure, rainwater collected from the roof of each door is put in a rainwater tank, and piping used for irrigation water etc. by each door and piping to be sent to the storage tank are attached. The volume of the tank varies depending on each house and is about 1 to 10 KL. The house tank on the hill is not equipped with a pump, and water is supplied by opening and closing a valve (not shown), while the house tank in the lowland is fitted with a pump. It has been. The number of units collected in the storage tank is set according to the local conditions, but if it is several units, it will take a long time to recover the cost for introducing this system, and the reduction effect of existing water resources is also limited. Therefore, practical implementation with 50 or more units is preferable.

  The volume of the storage tank is similarly set according to local conditions, but the general scale is about 100 KL to 50 ML.

  Rainwater is sent from this storage tank to a water treatment device, where it is purified by activated carbon filtration, filtration with a reverse osmosis membrane, etc., and chlorine is injected and used as clean water.

  Here, it is known that the activated carbon filtration device exhibits a biological treatment function by attaching microorganisms (biofilm formation) to the surface by long-term use in addition to the physical adsorption function of the activated carbon itself. This is called biological activated carbon.

  In normal water treatment, there is no problem because the water to be treated containing a large amount of dissolved oxygen is supplied into the activated carbon layer (even in the case of repair, it is about half a day at maximum), but in the rainwater utilization system of the present invention, The operation rate is as low as about 50%, and the supply of water to be treated may be stopped for a long time. In such a case, dissolved oxygen in water is consumed by microorganisms adhering to the activated carbon surface, resulting in an anaerobic state, and a decayed state is generated in the activated carbon layer. If this normal state of rot is allowed to stand, problems such as dissolution by hydrolysis of trace organic substances trapped in the activated carbon layer, reduction dissolution of metals, generation of malodor, and the like will occur.

  Therefore, when the supply of water to be treated to the activated carbon filter is stopped for a long time, according to the stop period, the following cleaning process is performed to prevent the occurrence of decay in the activated carbon filter, It can be kept in a state where predetermined performance can be exhibited.

(1) When the stop period is 1 to 2 days The dissolved oxygen in the activated carbon layer is completely consumed and dissolution of solid organic substances and elution of metal components proceed, but it does not lead to severe generation of bad odor. In this case, it is allowed to stand until resumption of water flow, and after the dissolution and elution of the above components have proceeded, it is washed with treated water and discharged.
(2) When the stop period is less than 3 to 10 days Supply air into the activated carbon layer. The supply speed is about 1/20 to 1/5 of the linear speed used in normal backwashing (to increase the oxygen transfer efficiency), and is performed until the dissolved oxygen concentration in the layer rises to about 50% of the saturation concentration. . This operation is performed at a frequency of once / day to three times / day.
(3) When the stop period is 10 days or more In order to suppress excessive growth of microorganisms in the activated carbon layer, normal backwash is performed at a frequency of once / 15 days to once / 10 days. Treated water can be used as the backwash water, but one having sodium hypochlorite added so that the effective chlorine concentration is 1 to 10 mg / L, preferably 3 to 10 mg / L is used. Addition of sodium hypochlorite is effective in suppressing the growth of protists such as rotifers and nematodes.

  FIG. 2 shows another configuration of the water treatment apparatus. In this apparatus, first, solid-liquid separation by MF membrane, chlorine sterilization treatment and the like are performed, and a part is taken out from the middle-water storage tank as middle water, and the remainder is further processed by the reverse osmosis membrane method The drinking water treatment appropriately selected according to the required water quality from the ion exchange method, the ultraviolet irradiation method, the chlorine sterilization method, the ozone treatment method, the pH adjustment, etc. is performed and used as clean water.

  Since the system of the present invention can effectively use rainwater as a whole, the utility value is particularly large in an area away from a river or the like.

Claims (4)

  In addition to providing pipes that use the internal water of individual rainwater tanks for irrigation water, car wash water, etc. in each house, provide water collection pipes that guide the overflow water of multiple individual rainwater tanks or the water in rainwater tanks to the storage tank, A water supply system that provides water treatment equipment to purify the water in the storage tank, and supplies the purified water to each house or surrounding area as intermediate water or drinking water   The water supply system according to claim 1, wherein the water treatment apparatus has a middle water production apparatus and a water production apparatus for further purifying the middle water production apparatus.   The water supply system according to claim 2, wherein the intermediate water production apparatus and / or the clean water production apparatus have an activated carbon filtration device.   The method for operating the water supply system according to claim 3, wherein when the supply of water to be treated to the activated carbon filtration device is stopped, a predetermined cleaning method according to the stop period is performed.

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