JP2020078779A - Facilities for recycling water - Google Patents

Abstract

To provide facilities for recycling water capable of utilizing a bactericide suitable for inactivating Legionella bacteria in recycling water without having toxicity.SOLUTION: A bactericide in a saturated solution of calcium hydroxide is provided. Facilities for recycling used water includes a drainage outlet 11, a water supply outlet 12, a water supply pipe, and an injection mechanism 3 for injecting a bactericide into the water supply pipe 2. Also provided is a method for sterilizing Legionella bacteria in recycling water by injecting a bactericide of 0.2% by weight into the recycling water.SELECTED DRAWING: Figure 1

Description

  TECHNICAL FIELD The present invention relates to equipment for circulating water capable of inactivating Legionella bacteria.

  A problem is known due to Legionella bacteria existing in water. Therefore, for example, as disclosed in Patent Document 1, a bactericide that inactivates Legionella bacteria is known.

  Here, when water is circulated and used, for example, in a bath, if the bactericide has toxicity, it may not be suitable for circulatory use.

JP2012-264228A

  An object of the present invention is to provide a facility for circulating water that uses a bactericide that is not toxic and is suitable for inactivating Legionella bacteria in the circulating water.

The facility for circulating water of the present invention,
A drainage outlet that drains the recycled water from the point of use to the water pipe,
An injection mechanism for injecting calcium hydroxide into the water supply pipe is provided.

  According to this feature, the Legionella bacterium can be inactivated by non-toxic calcium hydroxide.

The facility for circulating water of the present invention,
The water supply pipe may connect the drainage port and a water supply port for supplying water to the utilization point.

  According to this feature, it is possible to provide a facility for circulating water that inactivates the Legionella bacteria in the wastewater, supplies the water, and reuses it.

The facility for circulating water of the present invention,
A flow meter for measuring the flow rate of the water pipe is provided,
The injecting mechanism injects calcium hydroxide having a saturated concentration with respect to the flow rate measured by the flow meter.

  According to this feature, since calcium hydroxide having a saturated concentration is injected, high pH (12 or more) can efficiently inactivate Legionella. Moreover, since excess calcium hydroxide is not injected, the effect on the circulating water is small.

The facility for circulating water of the present invention,
A regeneration mechanism for lowering the pH of the circulating water is provided between the injection mechanism of the water supply pipe and the water supply port.

According to this feature, it is possible to neutralize the circulating water containing the strong alkaline calcium hydroxide.

The facility for circulating water of the present invention,
The use point is a bathtub,
It is characterized in that the circulating water is hot spring water or water hydrated with hot spring water.

  According to this feature, it is possible to provide a facility for circulating water that inactivates and supplies water for the water used in the bathtub of the hot spring. Calcium hydroxide, which has a small chemical reaction with active ingredients of hot spring water (salt, sulfur, etc.), can be used to keep Legionella bacteria inactive while keeping the active ingredients of hot spring water.

  According to the present invention, it is possible to provide a facility for circulating water that uses a bactericidal agent (calcium hydroxide) suitable for inactivating Legionella bacteria in the circulating water without toxicity.

FIG. 1 is a diagram showing equipment for circulating water. FIG. 2 is a diagram showing an experimental result in Shimizu. FIG. 3 is a diagram showing an experimental result in sewage. FIG. 4 is a diagram showing a wastewater treatment for inactivating Legionella.

Hereinafter, specific embodiments of the present invention will be described.

  FIG. 1 is a diagram showing equipment for circulating water. The circulating-use water facility C injects the hot spring water drained from the drainage port 11 of the bathtub 1 into the bathtub 1 again from the water supply port 12 via the water supply pipe 2. Hot spring water will be recycled water.

  Hot spring water (for example, salt water) is put in the bathtub 1 and used for bathing. The bathtub 1 is provided with a drainage groove 11 and a water supply port 12.

  It should be noted that the bathtub 1 may be replaced with other equipment (for example, a pool).

  The water supply pipe 2 is provided with a flow meter 21, a sterilization tank 23 and a regeneration tank 24. The flow rate is measured by the flow meter 21. The circulating water is retained in the sterilization tank 23 and the regeneration tank 24 for a certain period of time.

  The injection mechanism 3 has a container in which a disinfectant, which is calcium hydroxide, is enclosed, and injects the disinfectant into the sterilization tank 23.

  A valve 31 is provided in the injection mechanism 3, and a control mechanism (not shown) controls the valve 31 to adjust the injection amount of the sterilizing agent into the water supply pipe 2. The injection amount of the bactericide is set to be a saturated concentration with respect to the circulating water having the flow rate measured by the flow meter 21.

  The “saturation concentration” does not have to be exactly the amount of calcium hydroxide dissolved in the circulating water without excess or deficiency. Since the dissolved amount varies depending on the temperature of the circulating water and the like, it is difficult to strictly control the injection amount of the bactericide. It may be increased or decreased up to about 5% with respect to the dissolved amount.

  In addition, it is preferable that the calcium hydroxide to be used should comply with the food additive standard in order to ensure the safety of recycling in a bath facility.

  The regeneration mechanism 4 has a cylinder filled with carbon dioxide, and injects carbon dioxide into the regeneration tank 24. As a result, calcium hydroxide becomes calcium carbonate, and the pH of the circulating water decreases (approaches neutrality). In addition, a pH meter 42 is provided so that circulating water having a predetermined pH (for example, 8) or less is delivered to the water supply port 12.

  The regeneration mechanism 4 is provided with a valve 41, and a control mechanism (not shown) controls the valve 41 to adjust the injection amount of carbon dioxide into the regeneration tank 24. The amount of carbon dioxide injected is such that the injected germicide (calcium hydroxide) becomes calcium carbonate within a predetermined time. For example, 10 l/min.

  It is not preferable to return the saturated solution of calcium hydroxide having a pH of about 12 to the bath 1. Therefore, the pH is adjusted to about 8 by the regeneration mechanism. If there is a problem that the pH of the circulation-use water becomes weakly alkaline, not only the circulation-use water but also the source of the hot spring water can be supplied and alleviated at the water supply port 12.

  The configuration of the reproduction mechanism 4 is not limited to the above. For example, by injecting air instead of carbon dioxide into the regeneration tank 24, the pH can be lowered although the required time becomes long.

  Depending on the quality of the hot spring water, the effect of the hot spring may remain even if the pH is lowered by injecting an acid (for example, acetic acid). In such a case, the acid can be injected to lower the pH in a short time.

  In order to compare the effect of calcium hydroxide as a bactericide with sodium hypochlorite, which is widely used as a bactericide, the bactericidal effect and time were measured by experiments.

  The experiment was performed according to the following procedure. As the disinfectant, (1) a calcium hydroxide solution having a concentration of 1700 ppm (saturation), and (2) a sodium hypochlorite solution having a concentration of 200 ppm diluted with a sodium hypochlorite solution having a concentration of 12%, 2 I prepared the seeds.

  As a bacterial solution, a solution containing 108 to 109 bacteria in 1 ml and containing no calf serum as an organic substance (fresh water) and 5% added (sewage) was prepared.

As a reaction stop solution, a mixture of hydrochloric acid and 30% calf serum was prepared.

  An experiment in which 100 μl of the bacterial solution was added to 400 μl of the germicidal disinfectant and the reaction stop solution was added after 1 minute and 3 minutes was repeated 3 times. (Partially, 5 minutes later)

  Inactivation starts when the bacterial solution is added to the germicidal disinfectant. When a reaction stopping solution is added thereto, the action of calcium hydroxide is stopped by hydrochloric acid, and the action of sodium hypochlorite is stopped by calf serum. The number of inactivated bacteria can be measured in the time until the reaction stop solution is added.

  The experimental results are shown in FIGS. 2 and 3. The number of bacteria is a value of n=log10x, where x is the actual number of bacteria per ml. In addition, when the number of bacteria was less than 2.60, measurement was impossible, but in that case as well, it was shown as "2.60". In addition, the place where no experiment was conducted because it was meaningless to measure the number of bacteria was shown as "NT" (Not Tested).

  FIG. 2 is a diagram showing an experimental result in Shimizu. The calcium hydroxide solution was 3 minutes, and the sodium hypochlorite solution was 1 minute, and sufficient inactivation was achieved.

  FIG. 3 is a diagram showing an experimental result in sewage. A calcium hydroxide solution takes 3 minutes and a sodium hypochlorite solution takes 5 minutes, which is sufficient.

  The calcium hydroxide solution sterilizes both fresh water and sewage in 3 minutes, whereas the sodium hypochlorite solution requires 5 minutes for sewage. It is preferable that both clear water and dirty water can be inactivated in a short time. This is because it is difficult to increase the size of the sterilization layer 23 in order to retain the recycled water during the inactivation.

  From the above experimental results, it can be seen that the sterilization layer 23 can be surely sterilized if it has a capacity corresponding to the flow rate for 3 minutes (the maximum flow rate because the flow rate can change).

  The capacity of the sterilization layer 23 does not have to be the flow rate for 3 minutes. The time required for sure inactivation varies depending on the turbidity of the circulation-use water, etc., so that the design can be performed corresponding to the time.

  As described in detail above, the disinfectant of the present invention can inactivate Legionella bacteria in sewage in a short time. Further, even if the recycled water containing a bactericide is reused, there is no problem regarding toxicity in view of the fact that calcium hydroxide is recognized as a food additive.

  In hot springs that have an alkaline quality, the effect of acidic fungicides such as hypochlorous acid is diminished. The fungicide of the present invention is effective in hot springs having an alkaline spring quality.

  Although the circulating water is described as hot spring water, the scope of application of the present invention is not limited to this. For example, it can be used in a bathhouse using water that is not hot spring water. Further, it can be applied to an aquarium for swimming goldfish or the like, or can be used for an interior where the running water can be visually enjoyed. Further, the bactericide of the present invention may be used when industrial wastewater is recycled.

  Furthermore, the present invention can be applied to water that is drained to the sewage without being recycled. Instead of the water suction port 12, the water is drained to sewage. In that case, even if the regeneration mechanism 4 is omitted, the waste water is diluted with sewage and the pH is lowered, so there is no problem. (See Figure 4)

  It is a facility for circulating water that inactivates Legionella bacteria while maintaining the quality of the circulating water by using a fungicide suitable for inactivating the Legionella bacteria in the circulating water without toxicity. It can be considered to be used for many circulating water utilization facilities, especially in bathhouses.

C Facility for recycling water 1 Bath 11 Drainage port 12 Water supply port 2 Water supply pipe 21 Flow meter 23 Sterilization tank 24 Regeneration tank 3 Injection mechanism 31 Valve 4 Regeneration mechanism 41 Valve 42 pH meter

Claims (5)

A drainage outlet that drains the recycled water from the point of use to the water pipe,
A facility for circulating water, comprising an injection mechanism for injecting calcium hydroxide into the water supply pipe.   The facility for circulating water use according to claim 1, wherein the water supply pipe connects the drainage port and a water supply port for supplying water to the utilization point. A flow meter for measuring the flow rate of the water pipe is provided,
The facility for circulating water according to claim 2, wherein the injection mechanism injects calcium hydroxide having a saturated concentration with respect to the flow rate measured by the flow meter.   The circulating water utilization facility according to claim 2 or 3, further comprising a regeneration mechanism that lowers the pH of the circulating utilization water between the water injection port of the water supply pipe and the water supply port. The use point is a bathtub,
The facility for circulating water according to any one of claims 2 to 4, wherein the circulating water is hot spring water.