JP2008012462A - Method and system for cleaning and sterilizing filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a system for backwashing a filter by cleaning the inside of the filter vessel effectively and simultaneously removing sterilization by-products produced during the cleaning. <P>SOLUTION: The method of cleaning a filter comprises injecting a high-concentration chlorine agent into a pipe of the filter vessel, carrying out agitation and discharge of sterilization by-products into a gas phase through aeration and causing the bath water of the filter to flow back in order to clean the filter. The sterilization by-products discharged into the gas phase, e.g. trihalomethanes, are removed with e.g. activated charcoal. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cleaning method and system for effectively purifying the inside of a filtration tank and simultaneously removing disinfection by-products generated at the time of backwashing a filtration device.

  In a warm bath facility or pool, in order to suppress consumption and discharge of water, hot water in the bathtub is circulated, and a filter filled with a filter medium is installed in the circulation path to purify the hot water.

  However, in these purification operations of the filtration device type, since hot water circulates in the closed system, bacteria and suspended solids are not removed, so that the content ratio thereof gradually increases. In addition, bacteria and amoeba settle on the surface of the filter media and the inner walls of filter tanks, pipes, and bathtubs to form biofilms. The bacteria in these biofilms are protected from adverse factors such as disinfectants, and the amoeba that form the biofilms are cystized to protect themselves when they encounter obstacles such as disinfectants. It wo n’t die easily. Furthermore, these microorganisms repeat growth using organic substances derived from the body surface of the bath user as nutrient sources.

  In order to wash the suspended substances inside these filtration devices, reverse washing is performed to remove organic substances adhering to the filter medium by allowing water to flow backward from the lower part of the filtration tank and discharging water from the upper part. Is common. However, this method cannot completely remove the biofilm. In addition, organic substances derived from the body surface of the bathtub user have a lot of proteins and fats, and when these adhere to the filter medium surface and the inner wall surface of the apparatus, it is extremely difficult to remove by reverse cleaning. For this reason, harmful bacteria such as Legionella bred in the biofilm enter the bath water and have a harmful effect on the human body.

  For this reason, when disinfecting and cleaning the filtration equipment used for water treatment in warm bath facilities and pools, a method of backwashing with 5 to 10 ppm chlorine for more than 5 minutes (high concentration chlorine reverse cleaning method in the filter) Is known, and is effective in removing organic substances in the filter, controlling Legionella and amoeba, and suppressing unpleasant chlorine odor. However, when the inside of the filter is washed with high-concentration chlorine, a disinfection by-product is generated, and a part thereof remains in the filter and is circulated to the bathtub or the pool.

  Disinfection by-products are chemical substances generated with water disinfection, and many disinfection by-products have health hazards such as liver and kidney toxicity, carcinogenicity, and mutagenicity. In particular, when chlorinating agents are used for disinfection, organic substances in water (mainly natural organic substances such as humic substances) react with chlorine, and many halogens such as trihalomethane and haloacetic acid have been pointed out as carcinogenic health hazards. A monster is made.

  Cyanide chloride is also a disinfection by-product and is produced by treating water containing ammonia and organic substances with sodium hypochlorite. When cyanide chloride enters the body, it quickly changes to highly toxic cyanide.

Since the disinfection product shows toxicity even at a very low concentration, the standard value is set at a low concentration in the water supply standard as follows. (Chloroform (CHCL ₃ ): 0.06 mg / l, dibromochloromethane (CHBr ₂ CL): 0.1 mg / l, bromodichloromethane (CHBrCL ₂ ): 0.03 mg / l, bromoform (CHBr ₃ ) 0.09 mg / l, chloroacetic acid (CH ₂ CLCOOH): 0.02 mg / l, dichloroacetic acid (CH CL ₂ COOH) 0.04 mg / l, trichloroacetic acid (CCL ₃ COOH): 0.2 mg / l
The amount of disinfection by-products varies depending on conditions such as the amount of organic matter present, the amount of chlorine injected, the contact time with the disinfectant, the pH value, and the water temperature. In general, the concentration of disinfection by-products increases with increasing reaction time. In general, chemical reactions are said to double when the temperature rises by 10 ° C. Since the production of disinfection by-products is also a chemical reaction, the higher the water temperature, the higher the reaction rate and the higher the concentration. As for the pH value, the higher the pH, the more the trihalomethanes.

The use of chlorine as a disinfectant in hot bath facilities and pools is generally practiced and the generation of disinfection by-products is inevitable. When the concentration of trihalomethane in the bathroom air at 5 public baths was investigated, CHCL ₃ : 45 to 200 mg / m ³ , CHBrCL ₂ : 3.8 to 17 mg / m ^3, etc., all of which are CHCL ₃ >> CHBrCL ₂ > CHBr ₂ CL> CHBr ₃ in order, and the concentration of trihalomethane in the bathroom at the time of bathing in a general household is CHCL ₃ : 45 to 200 mg / m ³ , CHBrCL ₂ : 3.8 to 17 mg / m ³ , and only the CHCL ₃ concentration is prominent in public baths In some cases, a high tendency has been reported.

  Also, for example, hot spring water with water quality of pH: 8.0, potassium permanganate consumption: 183 mg / l, ammoniacal nitrogen: 32.3 mg / l, in Japan, pH is high, organic matter and ammonia concentration are extreme. There are many hot spring water. For this reason, there are not a few hot spring waters that satisfy the conditions for easily generating disinfection by-products, and the temperature condition of 35 to 45 ° C., which is a bathing temperature, also promotes the generation of disinfecting products.

  In general, in the case of tap water, when potassium permanganate consumption is 12 mg / l or more in surface water and chromaticity is 20 or more in groundwater, measures are taken against the occurrence of trihalomethane due to chlorination. This is being instructed by public institutions. Therefore, as a measure against disinfection by-products in water purification plants, there is a problem in removing work and work efficiency to remove chemical products once generated, so a water treatment method that suppresses the generation in advance is performed. From the standpoint that is effective, organic substances that are precursors of trihalomethane are removed by pretreatment operations such as coagulation sedimentation treatment.

  However, in the case of hot spring water, organic substances such as humic substances are prized as components that make the hot spring brown, and cannot be removed.

  In the past, the inventors have invented a system using chlorine dioxide that does not produce a disinfectant product as a cleaning and sterilizing method for hot spring water or a hot spring system filter as disclosed in Patent Document 1, but concentration measurement is difficult. However, there is a problem that the cost becomes high, and development of a cleaning and sterilizing method for a filter using chlorine has been desired.

  About the removal method of disinfection by-products, such as a trihalomethane, it can be made to discharge | release from a liquid phase to a gaseous phase by aeration, and it is publicly known that about 90% can be removed in 30 minutes by aeration. Also, adsorption treatment with activated carbon is possible, and the equilibrium adsorption amount of total trihalomethane is 0.65 mg / g for coconut husk charcoal and 0.5 mg / g for petroleum activated carbon.

JP-A-2005-313048

  In view of the above, the present invention has an object to effectively remove a biofilm composed of microorganisms such as bacteria and amoeba and sterilization of microorganisms, which are fixed in a filtration tank and a pipe attached to the filtration tank, during backwashing. It is said. The purpose is to build a system that can remove the disinfection by-products that are produced at the same time with high-concentration chlorine at low cost and sterilize organic matter such as biofilms and can effectively purify the filtration device. It is said.

  (1) Filtration characterized by injecting a high-concentration chlorine agent into a filtration tank or piping attached to the filtration tank, stirring by aeration, and then washing the filtration apparatus by backflowing the bath water of the filtration apparatus The problem is solved by providing a method for cleaning an apparatus.

  (2) In particular, the method for cleaning a filtration device according to (1) is characterized in that a disinfection by-product generated by purification with a high-concentration chlorine agent is treated by a removing means.

  (3) Further, the removing means is an adsorption treatment with activated carbon.

  (4) Filtration tank for filtering bath water, disinfectant supply means for sending chlorine agent into the filtration tank, pressure air supply means for sending pressure air into the filtration tank, and disinfection by-product The above-mentioned problem is solved by providing a filter cleaning system provided with a removing means for removing an object.

  (5) The filtration device cleaning system according to (4), wherein the removing means is an adsorption process using activated carbon.

  By using the cleaning method and the cleaning system of the filtration device according to the present invention, it is possible to remove the biofilm formed in the filtration tank and the amoeba inhabiting in the device and the organic matter serving as a nutrient source thereof. It is possible to provide an environment in which microorganisms such as Legionella bacteria that have a harmful effect on the human body cannot grow in the filtration tank or the pipes accompanying the filtration tank.

  By using high-concentration chlorine as a disinfectant, it is possible to increase the effect of removing organic substances in the filtration tank, and it is possible to reduce the chlorine-based disinfectant that has been conventionally consumed in a large amount of organic substances.

  By using high-concentration chlorine as a disinfectant, it is possible to increase the effect of removing organic substances in the filtration tank, and the production of chloramine is reduced, so that unpleasant chlorine odor in the bathtub or pool can be suppressed. .

  In order to increase the chlorine concentration of only the water in the filter at the time of cleaning, the chlorine agent cost is 1 compared to the high concentration chlorine reverse cleaning method in the filter to increase the chlorine concentration of the backwash water. It can be suppressed to about / 10 to 1/6.

  Since aeration is performed to bring the high-concentration chlorine in the filter into contact with the filter medium, disinfection by-products can be diffused into the gas phase, and a removal device such as activated carbon is used to remove dissipated disinfection by-products. It has less impact on the environment.

  Since the cleaning operation in the filtration apparatus by the system according to the present invention operates only at the time of reverse cleaning, the required amount of electricity and amount of chemical solution can be minimized.

  The system of the present invention can also be operated automatically, in which case there is little risk when adding a disinfectant and maintenance is easy.

  The method and system according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a conceptual diagram of this system, and FIG. 2 is a diagram inside a filtration tank. First, a normal filtration method will be described. Bath water flows into the filtration tank 2 from the bathtub through the hair remover 7 and is filtered by the filtration device 1. Thereafter, the water temperature is adjusted by the heat exchanger 3, and a chlorine-based disinfectant or the like is appropriately mixed and flows into the bathtub, thereby circulating water.

  The inside of the filtration tank 2 has a structure shown in FIG. 2, and has a filter medium 4 inside thereof. As the bathtub water flows in from the upper part of the filtration tank 2 and passes through the filter medium 4, the suspended substances are adsorbed on the filter medium 4, and the bathtub water is gradually purified.

  Next, backwashing will be described. The water is pushed from the lower part to the upper part of the filtration tank 2, and the biofilm and organic matter adhering to the inner wall of the filter medium 4 and the filtration tank 2 are lifted up. To drain. Thereafter, the filtration device 1 is operated to discharge only the initial filtered water, and the backwashing is completed. The object of the present invention is to effectively remove suspended substances adhering to the filter tank 2 as well as the filter medium 4 during the backwashing.

  The valve 9 adjusts the flow path of the bath water flowing into and out of the filtration tank 2 and plays a role of discharging the bath water that has been washed and drained during reverse cleaning. By using a five-way valve provided with valves in five directions as the valve 9, the inflow of bath water from the bathtub to the filter tank is directed to the upper and lower directions of the filter tank and from the filter tank. Although it can switch to a bathtub direction and an external drainage direction, it can also be made to acquire the same effect as when a five-way valve is used by using two or more three-way valves.

  During filtration, the valve 9 is adjusted so that the bathtub water flows from the bathtub to the upper part of the filtration tank 2 and so that the bathtub water that has passed through the filter medium 4 flows from the lower part of the filtration tank 2 to the bathtub. In the reverse cleaning, the bathtub water flows into the lower part of the filtration tank 2 from the bathtub, the bathtub water flows backward from the lower side to the upper side of the filter medium, and becomes the washing waste water from the upper part of the filtration tank 2 to the outside. The valve 9 is adjusted so that is discharged. When draining the initial filtered water performed after back washing, the bathtub water that has passed through the filter medium 4 is discharged from the lower part of the filter tank 2 to the outside so that the bathtub water flows into the upper part of the filter tank 2 from the bathtub. Adjust the valve 9 so that.

  As a disinfectant supply means for injecting the disinfectant solution 11 into the filtration tank 2, a conventional method is used. However, it is preferable that the injection amount can be adjusted using, for example, a pump 8 or a flow meter. .

  The operation of the method and system according to the present invention will be described. The disinfectant 11 is injected into the filter tank 2 in which the bath water is stored or into the pipe 5 attached to the filter tank 2. The disinfecting liquid 11 used at this time can use a chlorinated chemical.

  As the chlorinated drug, sodium hypochlorite, calcium hypochlorite, and organic chlorinating agents can be used. In this case, it is preferable to inject so that the concentration of free residual chlorine in the filtration tank 2 is 2 to 30 ppm, preferably 5 to 10 ppm. If the concentration is set high, a neutralizing agent can be added.

  Then, stirring by aeration is added, and the bath water in the filtration tank 2 and the disinfectant 11 are sufficiently mixed. A compressor 6 is used as a pressure air supply means, and pressure air can be sent into the filtration tank 2 to perform stirring. Since organic substances adhering to the filter medium 4 due to aeration and biofilms such as bacteria and amoeba are peeled off, these biofilms are in effective contact with the disinfecting solution 11 and can be killed.

  Further, disinfection by-products can be diffused from the liquid at the same time by aeration, and further, disinfection by-products in the air released from the air vent valve 10 provided at the top of the filtration tank 2 are removed by the activated carbon adsorption device 12. can do. The air vent valve 10 can be replaced with a manual two-way valve or an automatic two-way valve. When the discharge amount increases, a fan or the like is installed to facilitate the discharge of the air in the filtration tank.

  In addition, an air vent valve 10 and a pressure gauge 13 are provided in the upper part of the filtration tank 2 so that the pressure in the filtration tank 2 can be confirmed.

  When the disinfectant 11 is sufficiently agitated in the water, aeration is stopped and the bath water in the filtration tank 2 is made to flow backward from the lower part to the upper part. Do.

  After the backwashing is finished, the operation of the filtration device 1 is resumed, but it is desirable to drain the initial filtered water from the lower portion of the filtration tank 2 in order to clean the filtered water immediately after.

  In addition, this system is automated so that the amount of the disinfectant 11 to be added, the management of the concentration such as the PH value in the filtration tank 2, and the setting of the aeration time and backwash time can be set by the control panel. can do.

  An embodiment in the case of mixing sodium hypochlorite as the disinfectant will be described. A 12% aqueous sodium hypochlorite solution as the disinfectant 11 is injected into the filtration tank 2 or the pipe 5 associated with the filtration tank 2 until the free residual chlorine concentration in the filtration tank 2 reaches 10 ppm. Aeration is carried out with the compressor 6 for 10 to 60 minutes, preferably 30 minutes.

  The air supplied into the filtration tank 2 by aeration contains the disinfected disinfection product and is discharged from the air vent valve 10, and then the disinfection by-product is removed by the activated carbon adsorption device 12.

  After the aeration, the bathtub water is made to flow backward from the lower part of the filtration tank 2 to the upper part, and the bathtub water that has become waste water is discharged from the upper part of the filtration tank 2.

  Thereafter, the filtration operation can be resumed, but it is desirable to discharge the initial filtered water without returning it to the bathtub because the suspension during backwashing may remain.

  Table 1 shows the effect of washing and sterilizing the filtration tank 2 using sodium hypochlorite. Table 1 shows the water quality test results of the circulating filtration system.

  The number of amoeba in the filtration tank is 1 individual / ml even if it is not detected or detected, and it is presumed that amoeba was effectively removed by injecting high concentration chlorine and stirring by aeration.

  Legionella and coliform bacteria in the filtration tanks are not detected in all filtration tanks, and the number of general bacteria is also very low. Therefore, it is presumed that the bacteria were effectively sterilized.

  The consumption of potassium permanganate, which is an indicator of the organic matter in the filtration tank, is a very low value, suggesting that the cleaning was effectively performed.

  The water quality of the bathtub and pool is very low compared to the standards of the Ministry of Health, Labor and Welfare, and the water quality is kept clear. This is presumably because the filtration tank is effectively cleaned and sterilized and the filtration function is sufficiently exhibited.

  As a means for removing disinfection by-products, ozone treatment can be performed in addition to removal by activated carbon. After injecting ozone into the filtration device and stirring or aeration, sodium thiosulfate is added to remove residual ozone and residual chlorine. And aeration is stopped, the bathtub water in the filtration tank 2 is made to flow backward from the lower part to the upper part, the bathtub water which became waste water by the said washing | cleaning is discharged | emitted from the upper part, and reverse washing is performed.

  After the backwashing is finished, the operation of the filtration device 1 is resumed, but it is desirable to drain the initial filtered water from the lower portion of the filtration tank 2 in order to clean the filtered water immediately after.

  As a means for removing the disinfection by-product, a filter composed of a porous material such as zeolite or silica gel can be used.

  In that case, the disinfection by-product in the air discharged | emitted from the air vent valve 10 provided in the upper part of the excess tank 2 can be made to adsorb | suck to the filter comprised from a zeolite or a silica gel, and can be removed.

Conceptual diagram Diagram showing inside of filtration tank

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Filtration apparatus 2 Filtration tank 3 Heat exchanger 4 Filter material 5 Piping 6 Compressor 7 Hair removal device 8 Pump 9 Valve 10 Air vent valve 11 Disinfection liquid 13 Pressure gauge

Claims (5)

Washing the filtration device, injecting a high-concentration chlorine agent into the filtration tank or piping attached to the filtration tank, stirring by aeration, and then washing the filtration device by backflowing the bath water of the filtration device Method. The cleaning method for a filtration device according to claim 1, wherein a disinfection by-product generated by purification with a high concentration chlorine agent is treated by a removing means. The method for cleaning a filtration device according to claim 2, wherein the removing means is an adsorption treatment with activated carbon. Filtration tank for filtering bath water, disinfectant supply means for sending chlorine agent into the filtration tank, pressure air supply means for sending pressure air into the filter tank, and disinfection by-products are removed And a removing means for performing the filtration device cleaning system. The filtration apparatus cleaning system according to claim 4, wherein the removing means is an adsorption process using activated carbon.

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