JP2005131559A - Re-purification treatment method of tap water and re-purification treatment equipment therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a re-purification treatment method of tap water capable of easily re-purifying tap water in large quantities, and re-purification treatment equipment. <P>SOLUTION: Tap water 10 is guided to an activated carbon adsorbing tank 2 filled with activated carbon having a particle size of a 0.1-2.5 mm to be subjected to activated carbon treatment and the activated carbon-treated water 12 is guided to a fine sand filtration device 3 to be subjected to microbial treatment. The tap water 10 before subjected to activated carbon treatment in the activated carbon adsorbing tank 2 may be subjected to aeration treatment in an aeration tank 1. The purified water 13 microbially treated in the fine sand filtration device 3 is stored in a water tank 4 to be subjected to ultraviolet sterilization treatment or chlorine injection treatment. The water of the water tank 4 is again returned to the activated carbon adsorbing tank 2 to be subjected to circulating water purifying treatment. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a tap water repurification method and a repurification facility.

  What purifies tap water further is called a water purifier. In this method, tap water is filtered through activated carbon and then membrane filtered. As a result, organic substances, free chlorine, chloroamine, etc. in tap water are removed, and as a result, purified water having no off-flavor is obtained. However, this method is intended for drinking water in the kitchen and water to be put in a pot, and the amount of purified water is about 10 liters per day.

  On the other hand, a method in which only the activated carbon treatment is performed has been put into practical use in order to remove the odor of the salt in the shower and prevent discoloration of the hair. Activated charcoal is a method that pays attention to its low ability to adsorb trihalomethane but high ability to remove chlorine.

In purifiers, expensive devices with the functions of lead removal, alkaline ionized water, and acidic water production have been made.
However, the water purifier is intended only for drinking water and water used for cooking, and does not attempt to purify most household water such as kitchen dishwashing water, bath water, shower water, and wash water. Therefore, the present situation is that only a part of the user's wishes can be fulfilled.

  When extending the use of advanced water purification to baths, it is ideal to repurify all tap water used at home. Of course, if all households want this, the Waterworks Bureau should aim for further advanced water purification, but as a matter of fact, cost increases are inevitable, so it is appropriate to purify water in each household. .

  When repurifying most household water, it is not enough to simply scale up the current water purifier. That raises the cost problem first. Home water purifiers are equipped with membrane filtration, but membrane filtration is basically not backwashed. On the other hand, at the water purification plant, backwashing is performed every hour and chemicals are washed every six months. However, it is impractical to ask a household water purifier for this.

  Next, it is not appropriate to simply treat with activated carbon. Any activated carbon is not adsorbed and separated, and it is generally difficult to remove organic substances that are familiar to water. Therefore, the development of an apparatus and system that has a filtration method instead of membrane treatment and decomposes and removes substances that are difficult to adsorb with activated carbon is an issue.

  Tap water is often called red water and contains iron. This is because bacteria in water pipes erode the pipes and elute iron. It is difficult to remove soluble iron with current water purifiers. Development of an apparatus and a system that removes dissolved iron as well as turbidity of red water is desired.

  Water use is intermittent in homes. On the other hand, in order to perform normal filtration, water must be purified constantly or at a constant speed or less. This was one problem with the water purifier. That is, one tap of the water supply uses up to about 20 liters / minute, but in order to cope with it, water must be purified at the same speed. However, the reality is, for example, 2 liters / minute. Only 1/10 of the required amount is filtered. It should not flow more than 2 liters / minute, but it is left to the user. Therefore, performance is not guaranteed.

Therefore, the present inventor has proposed a fine sand filtration apparatus and method for decomposing organic substances in water with microorganisms in Japanese Patent Laid-Open No. 2003-275882 (Patent Document 1). Is not enough.
JP 2003-275882 A

  This invention solves the said problem, and proposes the repurification water treatment method and repurification water treatment equipment of the tap water which can perform repurification of tap water in large quantities and easily.

  As a result of intensive studies to solve the above problems, the present inventor has arrived at the present invention. That is, the present invention is characterized in that tap water is introduced into an activated carbon adsorption tank equipped with activated carbon having a particle size of 0.1 to 2.5 mm and treated with activated carbon, and this activated carbon treated water is introduced into a fine sand filtration device for microbial treatment. The summary of the repurifying water treatment method is as follows.

  According to this configuration, trihalomethane, chloroamines, free chlorine, etc. contained in tap water can be removed by the activated carbon treatment in the previous stage, and organic substances contained in tap water can be decomposed by the microbial treatment in the latter stage. Can be provided at low cost and in large quantities.

  In addition, the tap water before activated carbon treatment in the activated carbon adsorption tank is subjected to aeration treatment for 1 minute to 3 hours, so that not only free chlorine and chloroamines but also trihalomethane removal ability can be enhanced, and various others. In addition, it is possible to remove the low molecular weight substance, and in addition, it is possible to perform an iron oxidation process when red water is generated and an oxygen supply when oxygen is insufficient in a biological process at a later stage.

In addition, when the purified water treated with microorganisms by the fine sand filtration device is subjected to ultraviolet sterilization treatment or chlorine injection treatment, even harmless bacteria in the purified water can be removed, and safety can be further improved.
Furthermore, when at least a part of the purified water treated with microorganisms by the fine sand filtration device is returned to the activated carbon adsorption tank again and the circulating water purification treatment is performed, the activated carbon adsorption tank and the fine sand filtration device can be prevented from becoming anaerobic.

  In addition, the present invention is an activated carbon adsorption tank that performs activated carbon treatment on tap water including activated carbon having a particle size of 0.1 to 2.5 mm, and a fine sand filtration device that performs microorganism treatment on activated carbon treated water in the activated carbon adsorption tank. And a water tank for storing purified water that has been subjected to microbial treatment by the fine sand filtration device.

By using this repurified water treatment facility, the repurified water treatment method of the present invention can be easily realized.
In addition, an aeration tank may be provided in front of the activated carbon adsorption tank, and an ultraviolet sterilization apparatus or a chlorine injection apparatus may be provided in the water storage tank. Furthermore, it can also comprise the piping which supplies the purified water of a water storage tank to an activated carbon adsorption tank, and circulates purified water.

  In more detail, although the fine sand filtration method and apparatus of the said patent document 1 are applied to the repurification water treatment method and repurification water treatment equipment of the tap water of this invention, in the repurification water treatment of tap water, it is the most. The problem is disinfectant in tap water. The disinfectant is free chlorine and chloroamine combined chlorine. With this, the bacteria cannot propagate and become a simple filter. Therefore, in the present invention, an activated carbon adsorption tank is placed in front of the fine sand filter. Activated carbon can adsorb and remove chlorine.

  Of course, there is a limit to the adsorption of chlorine by activated carbon. I decided to do aeration. Aeration is effective in removing not only chlorine and chloroamines but also trihalomethanes. In addition to removing various low-molecular substances, there is an effect of supplying oxygen when oxygen is insufficient.

  The fine sand filtration device basically uses the one described in Patent Document 1, and uses fine sand of 0.25 mm or less. There are few organic substances in tap water, and red water is not always. Therefore, the development of the filtration membrane generated on the sand grain surface is insufficient. Therefore, fine sand must be used.

  Backwashing of the fine sand tank is basically performed. Even without backwashing, clogging usually does not occur for a long time, but clogging easily occurs depending on the quality of tap water. Clogging is evidence that the water is being further purified, but it is necessary to scrape the fine sand surface or remove the mud by backwashing as a real problem.

When backwashing, it is not always necessary to install an automatic backwashing device. If you need only piping, you can backwash manually if necessary.
The water purifier purifies only the required amount each time it is used. Therefore, even if the amount of purified water was one faucet, it was about 1/10 of the required amount. This cannot be used with confidence. In the present invention, the water passing through the fine sand is basically stored as purified water. In the case of a water purifier, water is purified as necessary, but this cannot be used for baths or showers. If fine sand filtration is used to handle a large amount of water at once, the equipment will be considerably larger. Therefore, a water tank is provided. The capacity of the water tank varies with the time pattern of use. Use a large amount of water in a short time at a time, and take a large water storage capacity when not using it later.

  Water use patterns are not averaged in the home. It is normal not to use at all from midnight to morning, and there are also cases where it is rarely used during the day. In such a case, stop inflow of tap water. But simply turning off causes problems.

  Bacteria are growing in the activated carbon adsorption tank and the fine sand filter tank of the fine sand filter. When the water flow stops, the bacteria can partially die and become anaerobic. Therefore, we decided to recycle the water once purified. It keeps flowing even if you don't use water. When the amount of water in the water storage tank is insufficient, tap water is poured, and when it is sufficiently stored, the water in the water storage tank is purified or the water just after the fine sand filtration is recirculated. This recirculation system does not make the activated carbon adsorption tank and the fine sand filtration tank anaerobic.

  The water in the water tank can be sent to the faucet as it is because there is almost no possibility of having pathogenic bacteria. In this case, the water becomes delicious. However, it is not completely sterile. In case of fine sand filtration, it contains a small amount of harmless general bacteria. Even if it contains bacteria, it will not reproduce because there is no organic matter to feed on, but some harmless miscellaneous bacteria will survive over time.

If you want to eliminate germs, install a UV lamp (sterilization lamp) in the water tank. The amount of ultraviolet rays may be a standard value. Also, ozone rays are not used. The goal is to remove bacteria.
Bacteria can be removed by ultraviolet rays in the water tank. Since it is impossible to irradiate the pipe connected to the water storage tank with ultraviolet rays, chlorine sterilization is performed instead of the aforementioned ultraviolet treatment when it is desired to sterilize the inside of the pipe. Although tap water contains chlorine, it is refilled with chlorine after clean water. In this case, unlike tap water, trihalomethane, ammonia, organic substances, etc. have already been removed, so no off-flavor is produced. It is also characterized by the absence of chloroamine, a chlorine odor.

  According to the method and facility for repurifying tap water of the present invention, repurification of tap water can be performed easily, and a large amount of safe and delicious water can be produced at low cost. Such a treatment system is particularly effective for the repurification of tap water using the river water and lake water of the city as raw water. In addition, unlike commercial water purifiers, a large amount of water can be used at one time, so it can also be used for baths and showers. Furthermore, it can be applied not only to household water but also to production of ultrapure water and purification of industrial water.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In FIG. 1, tap water 10 supplied to the aeration tank 1 is subjected to an aeration process by an aeration apparatus 5 provided at the bottom of the aeration tank 1. The aerated treated water 11 subjected to aeration treatment is guided to the activated carbon adsorption tank 2 and passes through the activated carbon 6 having a particle size of 0.1 to 2.5 mm filled in the activated carbon adsorption tank 2, so that the effect of the previous aeration process is achieved. In combination, the activated carbon-treated water 12 from which trihalomethane, chloroamine and free chlorine in the water have been removed is obtained.

  The activated carbon treated water 12 is guided to the fine sand filtration device 3, and the organic matter in the treated water is decomposed by microorganisms contained in the fine sand filtration layer 7 provided in the fine sand filtration tank 3a of the fine sand filtration device 3. . The obtained purified water (fine sand filtered water) 13 is sent to the water storage tank 4.

  The water tank 4 is provided with an ultraviolet lamp 8 to sterilize miscellaneous bacteria in the purified water. The sterilized treated water is used as domestic drinking water or bath water as purified water 14. The water tank 4 is provided with a pipe connected to the activated carbon adsorption tank 2 in the previous stage, and a part of the water stored in the water tank 4 is supplied to the activated carbon adsorption tank 2 again through this pipe. . Thus, the purified water always circulates in the system as the circulating water 19 so that the killing of microorganisms in the activated carbon adsorption tank 2 and the fine sand filtration tank 3a can be suppressed.

  In addition, 9 in the figure is a cover provided in the aeration tank 1, the activated carbon adsorption tank 2, the fine sand filtration tank 3 a, and the water storage tank 4. 15 and 16 indicate the flow of backwash water for activated carbon when the activated carbon adsorption tank 2 is backwashed, and 17 and 18 indicate backwash water for fine sand when the fine sand filtration tank 3a is backwashed. It shows the flow. Moreover, the aeration tank 1 may be omitted in this tap water repurification treatment facility.

The details of the above-described tap water repurification treatment facility will be described below.
The tap water 10 is processed in the aeration tank 1. The longer the aeration time, the better, but 3 hours is the practical limit. There is no particular restriction on the minimum time, but considering the rapid diffusion of the substance at the beginning of aeration, it is effective in 1 minute or more. Therefore, in the present invention, the aeration time is preferably 1 minute to 2 hours.

  Substances to be removed in the aeration tank 1 are low molecular weight compounds such as trihalomethane, disinfectant free chlorine and chloroamine combined chlorine. If the total chlorine is sufficiently aerated, about 2/3 is removed. Trihalomethane is also easy to remove by aeration, and it makes sense to consider that removal with activated carbon in the latter stage tends to be incomplete.

In addition, oxygen supply is important. In the case of red water, divalent iron ions are often dissolved in tap water, but first it is necessary to supply oxygen to promote oxidation of iron.
The aerated treated water 11 is subjected to the next activated carbon treatment. Although the size of the activated carbon adsorption tank 2 depends on the type of activated carbon used, it is approximately a fraction of that of the fine sand filtration tank 3a in the subsequent stage. The first purpose of the activated carbon adsorption tank 2 is to remove free chlorine and bound chlorine of chloroamine. If the disinfectant remains, the biological treatment of fine sand filtration in the latter stage will not work. Since activated carbon has a high chlorine removal capability, it may be about 1/10 when the purpose is only chlorine removal.

When the aeration tank 1 is omitted, a large amount of activated carbon must be added. In particular, when the aeration tank 1 is not used and trihalomethane removal is performed, it is necessary to increase the amount of activated carbon particularly.
The particle size of the activated carbon is 0.1 to 2.5 mm. When the particle size is larger than 2.5 mm (10 mesh), the adsorption capacity is rapidly lowered.

  There is a limit even if the adsorption power is large as the particle size is small. Below 0.1 mm, the filtration function becomes large and often has to be backwashed. Since the activated carbon adsorption tank 2 is smaller than the fine sand filtration tank 3a, it becomes impractical because the frequency of backwashing is particularly high.

  The activated carbon treated water 12 is subjected to fine sand filtration. The fine sand filtration rate is 2 to 100 m / day. Fine sand generally has an effective diameter of 0.05 to 0.2 mm. The outline of the apparatus and its water purification effect are as described in Patent Document 1.

  In principle, the backwashing device is necessary for both the activated carbon adsorption tank 2 and the fine sand filtration device 3. In the activated carbon adsorption tank 2, when the particle size is increased to 2 to 2.5 mm, the adsorption capability is lowered before clogging and the activated carbon is replaced. In this case, the backwash device can be omitted.

  The backwash device need not be automated. The frequency of backwashing is approximately once every two years or more, although it depends on the quality of tap water. Therefore, it can be dealt with by backwashing manually at the time of periodic inspection. As the backwash water, tap water can be used in the activated carbon adsorption tank 2, and purified water from the activated carbon treated water 12 or the water storage tank 4 can be used in the fine sand filtration tank 3 a.

The present invention employs a system that has a water tank 4 and constantly purifies water. Therefore, even if the water purifier is small, it can cope with changes in usage over time. Taking household equipment as an example, for example, the capacity of the aquarium is 1 m ³ . On the other hand, the amount of purified water is 100 to 150 liters / hour. At home, tap water may not be used for nearly 10 hours. During this time, the water is purified and the water tank 4 is filled.

The water in the water storage tank 4 is sent to the faucet by a pump. A part of it becomes the circulating water 19 described later.
When the water tank 4 is full, the water purification is no longer necessary. However, in the present invention, bacteria are propagated in both the activated carbon adsorption tank 2 and the fine sand filtration tank 3a to produce a filtration membrane. If the flow of this tank stops, the filter membrane may die. Then, it solved by circulating the purified water of the water storage tank 4 to the activated carbon adsorption tank 2. If the water tank 4 exceeds the required amount, the tap water valve is stopped and the circulation valve is opened. The amount of circulating water is preferably a steady water purification rate. Considering pump power, the circulating water volume can be reduced to about 1/2.

  The water tank 4 is preferably sterilized and disinfected. Recently, there are attempts to make tap water chlorine-free in Europe. In that sense, disinfection and sterilization are not necessarily required for household equipment.

In the case of chlorine sterilization, the circulating water 19 cannot use the water in the water storage tank 4. The fine water-filtered water 13 is circulated to the activated carbon adsorption tank 2 as it is.
It can be sterilized with ultraviolet rays. In this case, an ultraviolet lamp 8 is placed in the water storage tank 4, and this water can be used as the circulating water 19. The faucet pump and circulating water pump can be shared.

Next, the present invention will be described in more detail by way of examples.
Example 1
12 liters of tap water was placed in a 15 liter container and aerated at an air volume of 1.75 liters / minute. As a result, free chlorine was removed by 22% in 10 minutes, 50% in 30 minutes, and 72% in 120 minutes. Total chlorine was removed at 33% in 10 minutes and 41% in 30 minutes. In this example, the water depth was 21 cm. Therefore, if the water depth is 1 m, such an effect can be obtained in about 1/5 time. That is, the shortest aeration time is about 2 minutes, and the effect is about 10 minutes. If the amount of aeration is further increased, the effect can be enhanced, so the shortest time for aeration is about 1 minute.
Example 2
The activated carbon particle size and trihalomethane removal ability were tested. Coconut activated carbon was made into 4-10 mesh, 8-32 mesh, 30-60 mesh, and 400 ml was used. Tap water was allowed to flow at a rate of 5 liters / minute. The average trihalomethane removal rates for the first 5 hours were 35%, 76% and 98%, respectively. From this, it was found that the activated carbon is better as the particle size is smaller, and the maximum particle size is about 10 mesh.
Example 3
10 cm of fine sand having a particle diameter of 0.05 to 0.11 mm was placed in a vinyl chloride tower. The filtration rate was 30 ml / day. The filtration loss head was 35 cm. When the filtration rate is 10 m / day, the loss head is about 10 cm in the calculation. Therefore, such sand can be used in fine sand filtration. However, for activated carbon, a size of 0.1 mm or more is preferable considering that the tank is small and the filtration rate is high.
Example 4
Water treated by fine sand filtration at a filtration rate of 42 m / day is water higher than tap water, and this was subjected to fine sand slow filtration at a filtration rate of 10 m / day. As a result, the permanganate consumption was 50%. From this fact, it became clear that tap water produced by normal rapid filtration has a removal rate of permanganate consumption of 50% or more if fine sand filtration is performed. That is, it has the ability to halve organic matter. In particular, fine sand filtration is suitable for the decomposition of water-soluble components that are difficult to adsorb activated carbon, and it can be seen that activated carbon-fine sand filtration is a good system.
Example 5
A commercial water purifier was tested for performance. The specifications are about 500 milliliters of activated carbon and a water purification rate of 2 liters / minute. When water was purified at this rate, leakage of trihalomethane started from around 2000 liters. This value almost agreed with the specification. Chlorine is much more than that, and at least 5 times more can be filtered, but it was stopped halfway. According to the specifications, it was more than 10 times with respect to chlorine. This shows that removal by aeration is effective as a countermeasure against trihalomethane.
Example 6
Since red water is generated in the building tap water, this water was subjected to aeration treatment and activated carbon treatment, followed by fine sand filtration. The filtered water was completely removed with an iron concentration of 0.02 mg / liter or less.

It is a mimetic diagram showing the composition of the tap water repurification device in one embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Aeration tank 2 Activated carbon adsorption tank 3 Fine sand filtration apparatus 3a Fine sand filtration tank 4 Water storage tank 5 Aeration apparatus 6 Activated carbon 7 Fine sand filtration layer 8 Ultraviolet lamp 9 Cover 10 Tap water 11 Aerated treatment water 12 Activated carbon treatment water 13 Purified water (fine Sand filtration water)
14 Clean water 15 Backwash water for activated carbon 16 Backwash water for activated carbon 17 Backwash water for fine sand 18 Backwash water for fine sand 19 Circulating water

Claims (8)

Tap water is introduced into an activated carbon adsorption tank equipped with activated carbon having a particle size of 0.1 to 2.5 mm and treated with activated carbon, and the activated carbon treated water is introduced into a fine sand filter and treated with microorganisms. Re-purifying water treatment method. The tap water before the activated carbon treatment in the activated carbon adsorption tank is subjected to an aeration treatment for 1 minute to 3 hours. The method for repurifying tap water according to claim 1 or 2, wherein the purified water subjected to microorganism treatment with a fine sand filter is subjected to ultraviolet sterilization treatment or chlorine injection treatment. The repurified water treatment method for tap water according to any one of claims 1 to 3, wherein at least a part of the purified water subjected to the microorganism treatment by the fine sand filter is returned to the activated carbon adsorption tank to perform the circulating water purification treatment. An activated carbon adsorption tank for treating activated water with tap water having a particle size of 0.1-2.5 mm, a fine sand filter for microbial treatment of activated carbon treated in the activated carbon adsorption tank, and the fine sand filtration A tap water repurification facility characterized by having a water storage tank for storing purified water that has been microbially treated by the apparatus. 6. The tap water repurification facility according to claim 5, wherein an aeration tank is provided in front of the activated carbon adsorption tank. The repurification treatment facility for tap water according to claim 5 or 6, wherein an ultraviolet sterilization device or a chlorine injection device is provided in the water storage tank. 8. The tap water repurification treatment facility according to any one of claims 5 to 7, wherein a pipe for supplying purified water from the water storage tank to the activated carbon adsorption tank is provided to circulate the purified water.

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