JP6517137B2 - Operation management method of water purification equipment - Google Patents

Description

  TECHNICAL FIELD The present invention relates to the field of water treatment, in particular, to a method of managing operation of a water purification system used for advanced water purification in water supply.

  Japan is blessed with clean and abundant tap water sources such as river water, lake water and ground water. Conventionally, in water treatment plants, for example, the treatment shown in FIG. 1 of Patent Document 1 has been a general water purification treatment.

  Patent Document 1 describes a conventional water purification apparatus and a water purification apparatus and a water purification method using plant-based activated carbon with a low carbon dioxide discharge load, a technology related to the oxidizing action of ammonia by biological activated carbon in an activated carbon adsorption pond Moreover, the processing flow which combines a biological treatment oxidation pond is described in the front of the flow of the advanced water purification processing.

  This is basically intended to remove and disinfect, and as a water treatment agent, only flocculants such as aluminum sulfate and polyaluminum chloride and disinfectants such as chlorine and sodium hypochlorite have been used.

  However, Phromidium tenue, Anabaena which produces 2-methylisoborneol which is a mold odor substance, geosmin, etc. along with the increase of dam lakes for the purpose of securing tap water source as lifeline and progress of eutrophication of water source. spiroides var. Abnormal reproduction of algae such as crassa, Oscillatoria tenuis, and Microcystis aeruginosa, and the offensive odor development problems associated with this have occurred, and it has become difficult to cope with it by ordinary treatment.

As measures against this offensive odor, ozone treatment, biological treatment, activated carbon treatment, and the like have come to be performed in addition to the flow of normal treatment. Activated carbon has micropores with a large specific surface area as large as 1000 m ² / g and can remove organic substances such as mold odor substances. The activated carbon is classified into powdery activated carbon, granular molded activated carbon, and granular crushed activated carbon according to the difference in shape, and the granular molded activated carbon is formed into a columnar or spherical shape, granular crushed activated carbon is crushed and granular crushed material And so on.

  There are two flows shown in, for example, FIG. 2 and FIG. 3 of the patent document 1 in the flow using activated carbon as the offensive odor taste disorder countermeasure, and when the occurrence frequency of the offensive odor taste disorder is small, arrival only at the failure occurrence time. In the case where the frequency is high, a flow for performing permanent treatment is selected by installing an activated carbon adsorption pond on which granular activated carbon is laid, in order to cope with the problem of injecting powdered activated carbon into water wells and the like.

  Furthermore, in the 1970s, the carcinogenic substance trihalomethane (chloroform, bromodichloromethane, dibromochloromethane, bromoform, etc.) is a generic term for carcinogenic substances produced by the reaction of organic substances such as humic acid in water with the disinfectant chlorination agent. In the following, problems with organohalogen-based antiseptic byproducts including haloacetic acid, halal hydrate, etc., such as THM), have become apparent, and this has become a major problem that may cause the safety of the water supply. The organic matter that produces the above-mentioned disinfection by-products by reaction with chlorine during chlorination is called a precursor of the disinfection by-product, and this organic matter is efficiently removed, and the chlorine disinfection by-product is removed. Technology to reduce has come to be required.

  In addition, although ammonia nitrogen contained in tap water tends to increase due to the progress of eutrophication of water source, etc., ammonia nitrogen is a chlorine agent used for water disinfection (liquid chlorine, sodium hypochlorite In order to cause an off-flavor taste, which is called so-called karuki odor, to react with the water, it causes unfavorable tap water.

  For this reason, from the viewpoint of supplying safe and delicious water, review the chlorinating agent addition position, biological activated carbon BAC: (Biological Activate Carbon, organic substance decomposition action by the metabolizing function by microorganisms propagated on the surface, and nitridation action of ammonia nitrogen Advanced water purification treatment aimed at control of chlorination byproducts such as treatment of granular activated carbon) has been considered in earnest.

  The BAC treatment is based on a combination of aggregation treatment + ozone treatment + granular activated carbon treatment + post chlorination treatment. First, removal of residual organic substances by BAC treatment is carried out through oxidization and decomposition of the residual organic substances and degradation of molecular weight and biodegradability by ozonization, followed by turbidity removal by coarse treatment and rough removal of organic substances, followed by ozonation. Biodegradation as well as reduction of ammoniacal nitrogen is carried out, and after the organic nitrogen which is the precursor of the disinfection by-product and ammonia nitrogen are reduced as much as possible, the disinfection with the chlorinating agent is carried out. However, it is generally said that it takes about 3 to 6 months because microorganisms need to propagate on the surface of the granular activated carbon in order to BAC convert unused granular activated carbon.

  As described above, the process flow of the water purification process using granular activated carbon is shown in FIG. 3, FIG. 4, FIG. 5, and FIG. 6 of Patent Document 1 depending on the presence or absence of combined ozone treatment and the arrangement position of activated carbon. Four types are representative, and granular crushed activated carbon having a particle size adapted to each use has been used.

  Downward-flowing activated carbon adsorption ponds in front of sand filtration ponds are large particle size coal systems with a particle size of 0.85 mm to 2.0 mm, an effective diameter of 1.1 to 1.3 mm, and an even coefficient of 1.3 or less. Granular crushed activated carbon (FIG. 4 of Patent Document 1), downward-flowing activated carbon adsorption ponds placed behind sand filters, each having a particle diameter of 0.5 mm to 2.0 mm, an average diameter of 0.9 to 1.1 mm, A medium particle size coconut shell-based granular crushed activated carbon and coal-based granular crushed activated carbon (FIG. 5 of Patent Document 1) of medium particle diameter with uniform coefficient of 1.5 to 1.9, upward flow fluidized bed activated carbon adsorption pool, Coal-based granular crushed activated carbon (Fig. 6 of Patent Document 1) having a small particle diameter of 2 mm to 1.7 mm, an effective diameter of 0.35 to 0.45, and a uniform coefficient of 1.4 or more is generally used. .

  In addition to the above, in the above process flow, a method of combining a biological oxidation treatment pond in the former stage of the coagulation sedimentation basin, a filtration pond further in the latter stage of medium particle size downward flow activated carbon adsorption pond as shown in FIG. There is also a method of combining (including coagulation filtration).

  Incidentally, even in the case of granular activated carbon not using ozone treatment in combination, or biological activated carbon using ozone treatment in combination, since the organic substance having no biodegradability is gradually accumulated, the adsorption performance is gradually lost. The activated carbon from which the adsorption performance is almost lost in this way is referred to as degraded carbon etc., but it is possible to reapply the organic substance removing ability as the activated carbon by performing periodical activation regeneration.

  Humid substances (organic coloring substances such as humic substances, humic acids, and fulvic acids), which are the precursors of chlorination by-products, degraded coal of activated carbon for water supply, geosmin, which is an offensive odor component, and 2-methylisoborneol And the like, but it is general that a steam regeneration method at a temperature of 800 to 950 ° C. is adopted for regeneration of degraded coal of these coal-based crushed charcoal and coconut shell-based crushed charcoal. The activated carbon to which this organic substance removing ability is reapplied is called regenerated carbon.

  However, since the microorganisms that were propagating on the surface are lost in the process of water vapor regeneration, when the regenerated carbon is returned to the activated carbon adsorption pond, 3 months to 3 months as with unused activated carbon until the regenerated carbon becomes BAC. It takes about six months.

  Moreover, if an example of a microbe adhesion carrier is shown, for example, after making a liquid mixture of polyvinyl alcohol and sodium alginate drop in calcium chloride solution and producing a spherical gel, patent document 2 freezes and thaws the spherical gel. And a carrier adhering to bacteria that has been rendered insoluble by treatment with sodium sulfate.

  Furthermore, as a comprehensive immobilization carrier that encases the cells inside, for example, Patent Document 3 discloses bacterial entrapment which is obtained by entrapping and immobilizing the microorganism in a diester of polyethylene glycol or a polymer gel of monoester of methoxypolyethylene glycol. A fixed carrier is disclosed.

JP 2011-45853 A Unexamined-Japanese-Patent No. 5-271425 Japanese Patent Publication No. 64-9072

  However, as described above, the advanced water purification treatment is a safe and delicious trump card, but it still has problems to be solved in terms of ammonia nitrogen removal. That is, in the BAC treatment, ammonia nitrogen is oxidized to nitrate nitrogen and reduced by nitrite bacteria / nitrite bacteria propagated on the activated carbon surface, but these microorganisms have a low temperature of less than 20 ° C. (especially 10 ° C. or less) It had the disadvantage that the activity decreased significantly when the water temperature reached.

  In addition, in the high water temperature season such as summer, a large amount of clean snow water is supplied from the upstream area of the water source, so the river flow is also large, and the ammonia nitrogen concentration can be maintained as low as 0.1 mg / L. However, since the river water volume decreases in low water temperature seasons such as winter, the influence of the water quality of the inflowing river lacking in cleanliness in the urban suburbs becomes high, and the ammoniacal nitrogen concentration becomes high as 2 mg / L or more There is also. Thus, there is a problem that the ammoniacal nitrogen concentration can not be sufficiently reduced by the conventional BAC treatment alone, since the ammoniacal nitrogen concentration tends to increase conversely at the low water temperature period when the biological activity decreases. .

  The remaining ammoniacal nitrogen can be decomposed by performing chlorination of breakpoints as described below during chlorination (referred to as post-chlorination) performed in the final step of water purification treatment, but ammonia Since the decomposition of volatile nitrogen requires 7.4 times the stoichiometric amount of free chlorine, higher residual ammoniacal nitrogen concentration requires more chlorine to be added, and increases disinfection byproducts such as trihalomethane. It is desirable to completely remove ammonia nitrogen at a stage before post-chlorination, in order to by-produce an off-flavoring substance derived from combined chlorine known as so-called pulpy odor.

(Breakpoint processing)
2NH ₃ + 6Cl ₂ → N ₂ + + 6HCl

  In addition, there is also a problem that ammonia nitrogen can not be removed during the period until these granular activated carbons become BAC, even when either unused coal or regenerated coal is used.

  The present invention has been made in view of the above-mentioned conventional problems, and the object of the present invention is to prevent the activity decrease of the microorganisms adhering to activated carbon in the water purification treatment using ammoniacal nitrogen-containing water as a water source, ammonia It is an object of the present invention to provide an optimum operation management method of a water purification treatment equipment capable of suppressing residual nitrogen concentration to low concentration.

In order to solve the said subject, the operation management method of this invention can be set as the following structures.
(1) In the operation management method of the water purification equipment for nitrifying the ammonium ions contained in the water to be treated with nitrifying bacteria, the water temperature is 10 ° C. to 35 ° C. and ammonium ions having a higher concentration than the water to be treated are The nitrifying bacteria are acclimatized in advance with the aqueous solution for conditioning contained. When the temperature of the water to be treated drops below 20 ° C., the water to be treated is brought into contact with the acclimated nitrifying bacteria to carry out the nitrification step.
(2) The ammonium ion concentration can be defined as an ammonium nitrogen concentration, and the ammonium nitrogen concentration of the aqueous conditioning solution is preferably 1 mg / L or more and 30 mg / L or less.
(3) Coagulative sedimentation basin where flocculating agent is added to treated water to coagulate and precipitate, ozone contact pond where ozone is brought into contact with treated water, activated carbon adsorption pond which carries out activated carbon adsorption treatment of treated water, treated water When operating and managing a water purification treatment facility having a filtration basin for filtering, at least one of the activated carbon adsorption ponds is loaded with nitrifying bacteria, and the nitrifying bacteria are brought into contact with water to be treated to carry out the nitrification step Can.
(4) The place of the acclimatization process is not particularly limited, and can be performed at least one of the outside and the inside of the activated carbon adsorption pond.
(5) A plurality of activated carbon adsorption reservoirs can be installed. In this case, one or more activated carbon adsorption reservoirs are used as a reserve reservoir, and the other 1 or more activated carbon adsorption reservoirs carry out adsorption treatment of the water to be treated. When the water temperature of the water to be treated drops below a predetermined temperature, it is possible to switch the water flow of the water to be treated from the activated carbon adsorption reservoir to be subjected to the adsorption treatment to the reserve reservoir and to perform the nitrification step.
(6) The place of the nitrification step is not particularly limited in the water purification treatment equipment as described above. For example, it is possible to install a nitrification tank carrying nitrifying bacteria at least upstream of the coagulation sedimentation tank, and to carry out the nitrification process by bringing the water to be treated prior to coagulation precipitation into contact with the nitrifying bacteria after the acclimatization process.
(7) A nitrification tank is installed on either or both of the upstream side and the downstream side of the filtration basin, and the nitrifying bacteria after the acclimatization process are treated water before filtration and / or after filtration. The nitrification step can also be carried out by contacting.
(8) Furthermore, install a nitrification pond at least between the flocculation settling basin and the ozone contact pond, and after the flocculation settling treatment, the nitrifying bacteria after the acclimatization process should be treated water before contacting with ozone. The nitrification step can also be carried out by contacting.
(9) Measure one or both of the ammonium ion concentration of the water to be treated and the water temperature, and control one or both of the ammonium ion concentration of the acclimatized aqueous solution and the start time of the nitrification process based on the measured data It is preferable to do.
(10) It is also possible to regenerate either one or both of the activated carbon adsorption reservoir with lowered organic substance adsorption capacity and the nitrification pond with lowered nitrification capacity.
(11) Furthermore, the water to be treated may be chlorinated after the nitrification step.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is a low water temperature period, the residual ammonia nitrogen concentration of treated water can be suppressed by using the nitrifying bacteria which adapted under high concentration ammonium ion.

It is a schematic diagram which shows the 1st example of the water purification treatment installation used for this invention. It is a schematic diagram which shows the 2nd example of the water purification treatment installation used for this invention. It is a schematic diagram which shows the 3rd example of the water purification treatment installation used for this invention. It is a schematic diagram which shows the 4th example of the water purification treatment installation used for this invention. It is a schematic diagram which shows the 5th example of the water purification treatment installation used for this invention. It is a schematic diagram which shows the 6th example of the water purification treatment installation used for this invention. It is a schematic diagram which shows the 7th example of the water purification treatment installation used for this invention.

  Hereinafter, the present invention will be specifically described, but the present invention is not limited to a specific example. The present invention comprises the steps of adapting a microorganism useful for water treatment, and utilizing the adapted microorganism for the treatment such as nitrification.

  The specific example will be described below.

<Microbial>
The present invention is not particularly limited as long as it is a microorganism (yeast, fungus, bacteria) contributing to the water treatment process, and multiple types of bacteria can be used, but in particular, decomposition and removal of ammonia nitrogen Use useful microorganisms. In the present invention, bacteria that contribute to the oxidation of ammonia nitrogen and the oxidation of nitrite, that is, at least one, preferably both nitrate bacteria (nitrite bacteria) and nitrite bacteria (nitrite bacteria) can be used, Such bacteria are referred to herein as nitrifying bacteria.

  The utilization method of these nitrifying bacteria is not particularly limited, but it is preferable to adhere to (adhere to) a carrier to be familiar.

<Carrier>
The nitrifying bacteria adhere to (adhere to) the carrier and become familiar. The carrier is not particularly limited, and any one or both of a carrier with bacterial adhesion to which nitrifying bacteria adheres to the surface and a carrier for immobilization with bacteria immobilized inside may be used.

  The bacteria-adhering carrier is not particularly limited, but an example is an insolubilized gel. The insolubilized gel is, for example, a mixture of polyvinyl alcohol and sodium alginate dropped in calcium chloride solution to form a spherical gel, and then the spherical gel is insolubilized by freezing / thawing treatment or sodium sulfate treatment. .

  It is also possible to use other carriers together with the insolubilized gel or separately from the insolubilized gel. Other carriers include any of activated carbon materials (for example, granular activated carbon), crushed anthracite, crushed charcoal, crushed natural zeolite, molded artificial zeolite, molded particulate resin, glass fiber, plastic fiber, porous ceramic body, etc. It is possible to use one or more materials. Among them, as the particulate resin molded product, resin molded products of polyurethane foam, polyvinyl alcohol, polypropylene, polyethylene, polyethylene glycol and cellulose raw materials can be used.

  As the entrapment immobilization carrier, for example, a bacteria entrapping immobilization carrier formed by entrapping and immobilizing the microorganism on the inside of a polymer gel of a diester of polyethylene glycol or a monoester of methoxypolyethylene glycol can be used. In addition, the bacteria inclusion fixation carrier is not limited to this, and it is possible to contain microorganisms such as nitrifying bacteria inside the carrier, for example, polyacrylamide, agar, carrageenan, collagen, polyvinyl alcohol, alginic acid as a raw material Granular gel can be used.

There is no particular limitation on the method of attaching (fixing) the nitrifying bacteria to the carrier, but there are no particular limitations on the nitrifying bacteria obtained by separately or separately culturing nitrifying bacteria, commercially available nitrifying bacteria, or water or soil that may contain the nitrifying bacteria alone or in combination. Contact the support as a source. Water or soil that is a source of nitrifying bacteria is not particularly limited, and various types such as sludge water and seawater can be used, but preferably water to be treated (before chlorination) to be subjected to nitrification treatment Use as a source.
Next, the process of habituation of nitrifying bacteria will be specifically described.

<Familiarization process>
For adaptation, an adaptation aqueous solution containing water as a main component and having a higher ammonium ion concentration (ammoniacal nitrogen concentration) than the water to be treated is used. The aqueous solution for familiarization includes, for example, treated water before or during treatment in a water purification treatment facility, treated water after treatment in a water purification treatment facility, water not to be treated in a water purification treatment facility (river water, rain water, drainage, etc. ) Or various water sources such as tap water can be used, and two or more of them can be used as a mixture. However, when containing a nitrifying bacteria inhibitor such as chlorine at a high concentration, pretreatment such as dechlorination is required.

  The aqueous conditioning solution needs to maintain the ammoniacal nitrogen concentration higher than that of the water to be treated. Here, the water to be treated, which is the standard of the ammoniacal nitrogen concentration, may be before introduction into the water purification treatment facility (raw water) or may be treated during treatment, but preferably the low water temperature period (water temperature 10 ° C. Based on the treated water other than As described later, the ammoniacal nitrogen concentration of the water to be treated as a reference may be measured during the water purification treatment, or a reference value may be set from measurement data in the past.

  Generally, the higher the concentration of ammoniacal nitrogen concentration in the adaptation aqueous solution, the process stability of the nitrification process improves, but if the concentration is higher than necessary, the cost becomes high, and high pH adversely affects nitrifying bacteria. In some cases. On the contrary, if the ammoniacal nitrogen concentration of the aqueous solution for adaptation is too low, the duration of the nitrification effect becomes short, and it can not cope with the subsequent decrease in the water temperature of the water to be treated or the increase in the ammoniacal nitrogen concentration. Can also be set.

  Specifically, the ammoniacal nitrogen concentration of the aqueous solution for adaptation is preferably 1 mg / L or more, more preferably 3 mg / L or more, and 5 mg / L or more More preferable. The upper limit thereof is not particularly limited, but is preferably 30 mg / L or less, more preferably 10 mg / L or less.

  If the ammoniacal nitrogen concentration of the aqueous conditioning solution is low, ammonia is added in the form of ions or salts. Moreover, it is also possible to add an additive such as a pH buffer, an acid, an alkali, or a saccharide to the aqueous solution for conditioning if it is a substance that does not inhibit the culture of nitrifying bacteria.

  Heating or cooling any one or more of an aqueous solution for adaptation, a carrier carrying nitrifying bacteria, and an apparatus (tank, pond, column, etc.) containing nitrifying bacteria (carrier), and maintained at a temperature of 10 ° C to 35 ° C. Perform the familiarization process. Preferably, the water temperature of the conditioning aqueous solution is maintained at 10 ° C. or more and 35 ° C. or less. The time period required for habituation is not particularly limited, and can be appropriately changed depending on the dissolved oxygen concentration, ammonium ion concentration, initial loading amount of nitrifying bacteria and the like, but it is preferable to provide a two week or more habituation period. The nitrifying bacteria that have undergone the acclimatization process are subsequently used in the nitrification process.

<Nitrification process>
In the present invention, the above-mentioned acclimatization process is applied to the untreated water whose water temperature has fallen below a certain temperature, or the nitrification of the untreated water whose ammonia nitrogen concentration has risen above a predetermined concentration even if the water temperature is above a certain temperature. Use nitrifying bacteria to increase the nitrification efficiency of the water purification equipment. Although the treatment stability is high even if utilization of the nitrifying bacteria that has passed through the adaptation step is started at a high water temperature period, if the start time is too early, it can not cope with the subsequent low water temperature period and the increase in ammoniacal nitrogen concentration.

  Therefore, the judgment of the start time of the nitrification process (end of the acclimatization process) should be made periodically (always or continuously) or at least once in either one of the water temperature of the water to be treated and the ammonia nitrogen concentration. And, if necessary, comprehensively judge against other accumulated data. Such data can also be used to set the conditions (ammoniacal nitrogen concentration, temperature) of the acclimatization process. As other data that can be used other than actual measurement, in addition to data measured with the same water purification treatment facility in the past, data acquired with other water purification treatment equipment (including past data), published data (Ministry of Health, Labor and Welfare Water Quality Database, A variety of data can be used, such as the Ministry of Land, Infrastructure, Transport and Tourism water quality and water quality database etc. The ammonium nitrogen concentration (ammonia nitrogen concentration) can be measured, for example, by the ion electrode method (JIS K 0101, 36.4, etc.)

  Specifically, the water temperature less than 20 ° C. or 15 ° C. or less is set as the set temperature, and the nitrification step is started when the water temperature drops below the set temperature. However, when the possibility of water temperature decrease of treated water is low, such as in a warm area, the nitrification process should be performed at a water temperature of 10 ° C or more, preferably 15 ° C or more, more preferably 20 ° C or more, considering only nitrification efficiency. It can start. In this case, for example, the time when the ammoniacal nitrogen concentration of the water to be treated exceeds a predetermined concentration is taken as the start time of the nitrification step.

  The method for bringing the nitrifying bacteria into contact with the water to be treated is not particularly limited. For example, together with the carrier on which the nitrifying bacteria are fixed, it may be replenished (added) to the filling material of the water treatment equipment (eg, filled activated carbon). And may be replaced with part or all of the filling material. Furthermore, a nitrification tank (nitrification tank) in which nitrifying bacteria are accommodated in a vessel such as a column or tank may be incorporated into the water purification treatment facility and used. The shape and structure of the nitrification tank are not particularly limited, and may be, for example, a fixed bed, fluidized bed, biofilm type, and may be upflow or downflow.

  Next, the water purification equipment using the nitrification tank and its operation management method will be specifically described.

<Water treatment facility>
1 to 5 show specific examples of the water purification equipment. In addition, although the activated carbon adsorption reservoir shown in FIGS. 1-5 is a fixed-bed downflow type thing, it may be a fluidized bed upflow type. The structure of these water purification facilities is not particularly limited, but common structures (devices) will be described below with the same reference numerals. Each water treatment facility has a coagulation sedimentation basin 10. The coagulation sedimentation tank 10 is directly or indirectly connected to a source of raw water (water to be treated) directly or through a pretreatment unit (such as a water receiving well), and untreated water to be treated or at least a part thereof is The treated water to be treated is supplied to the coagulation settling tank 10.

  In the coagulation sedimentation tank 10, one or more flocculants (inorganic flocculant, polymer flocculant, flocculant aid, etc.) are added to the water to be treated by manual or mechanical means, and stirred to grow floc. The floc is separated by a solid-liquid separation device constituted by any one or more of the devices of a part of the coagulation settling tank 10 and the devices downstream of the coagulation settling tank 10.

  For example, the coagulation sedimentation basin 10 has a sedimentation basin 12 on the downstream side of the coagulation basin 11 in addition to a coagulation basin 11 for adding and stirring a coagulant, and the sedimentation basin 12 is provided with a sloped plate or a sloped pipe Floc precipitates (solid-liquid separation). The solid-liquid separation device is not limited to this, and may be a combination of the membrane separation device of FIGS. 6 and 7 and the coagulation tank 11 described later, or a combination of a coagulation sedimentation basin and a sand filtration basin (filtration unit). It may be a combination. Moreover, it may be a combination of a coagulation tank and a sand filter (filter device) without a settling tank.

  Here, one or more other devices are installed on the downstream side of the coagulation settling tank 10, and the water to be treated (liquid phase) after the floc has been separated is further treated. Specifically, one or more of the ozone contact pond 21, the activated carbon adsorption ponds 25 and 31, and the sand filtration pond 28 are installed downstream of the coagulation sedimentation basin 10, and the number and the installation order of these are as follows. Although not particularly limited, preferably, the ozone contact pond 21, one or more activated carbon adsorption ponds 25 and 31, and the sand filtration pond 28 are installed in the order described.

  Although various activated carbons can be used for the activated carbon adsorption reservoirs 25 and 31, activated carbons that can be used also in the prior art, that is, large particle size (particle diameter 0.85 mm to 2.0 mm, effective diameter 1.1 to 1) .3 mm, uniformity coefficient 1.3 or less, medium particle diameter (particle diameter 0.5 mm to 2.0 mm, average diameter 0.9 to 1.1 mm, uniformity coefficient 1.5 to 1.9), small particle diameter Particle size 0.2 mm to 1.7 mm, effective diameter 0.35 to 0.45, uniformity coefficient 1.4 or more) any of coal type, plant type, polymer resin type raw material; crushed, Any of spherical and cylindrical shapes may be used, and two or more may be used as a mixture or a separate layer.

  On the other hand, the sand filtration pond 28 is filled with one or more kinds of filter media such as filter sand (silica sand), anthracite, garnet, manganese sand, ceramic and the like. Therefore, the water to be treated (liquid phase) after precipitation and separation of floc is subjected to ozone treatment in the ozone contact pond 21, residual substances are adsorbed and removed in the activated carbon adsorption ponds 25 and 31, and further filtered in the sand filter pond 28. And treated water from which residual contaminants have been removed.

  In addition, it is also possible to provide an after-treatment part downstream of the removal process of a residual contaminant. Specifically, a chlorine agent such as sodium hypochlorite may be added to the treated water, and the mixture may be chlorinated (post-chlorination treatment) to form purified water such as tap water. In the present invention, the nitrification step is performed before the post-treatment (chlorination), that is, between the raw water and the treated water.

  It is necessary to measure the condition of the water to be treated for this nitrification step and the above-mentioned fitting step. Specifically, a measurement sensor is installed in the water purification treatment facility, or water to be treated (raw water) is collected from the inside of the water purification treatment facility or from the former stage, and at least one ammonia nitrogen concentration of the water to be treated, preferably Both are measured and used in one or both of the acclimatization step and the nitrification step as described above.

  When acquiring data from the treated water inside the water purification treatment facility, the measuring place is not particularly limited as long as it is before chlorination, and the treated water at only one place or plural places may be measured. The preferred data measurement site is at least one location of the activated carbon adsorption pond 25 and piping (inflow water, outflow water) before and after it, and additionally, the nitrification pond (preliminary pond) described later and piping before and after it It is preferable to measure (influent water, outflow water).

  Hereafter, the specific example of the water purification treatment installation which integrated the nitrification tank is demonstrated.

<First example>
In the water purification treatment equipment of the first example shown in FIG. 1, one or more activated carbon adsorption ponds 25 and 31 are installed in series or in parallel, preferably two or more activated carbon adsorption ponds 25 and 31 are more preferably Three or more activated carbon adsorption ponds 25 and 31 are installed in parallel. Of these activated carbon adsorption reservoirs 25 and 31, one or more, preferably two or more activated carbon adsorption reservoirs 31 are used as reserve reservoirs, and water to be treated is passed through reserve reservoir 31 or seeded with nitrifying bacteria separately Establish nitrifying bacteria.

  The reserve reservoir 31 can flow water independently of the other activated carbon adsorption reservoirs 25 by opening and closing the valve. In the high temperature phase where the water temperature of the treated water to be measured exceeds 10 ° C., more preferably 20 ° C. or more, the treated water is passed through the activated carbon adsorption pond 25 to carry out a normal activated carbon adsorption treatment.

  At this time, the ammoniacal nitrogen concentration of the to-be-treated water is measured or predicted, and the acclimatization aqueous solution in which the ammoniacal nitrogen concentration is higher than that of the to-be-treated water is passed through the reserve reservoir 31. As described above, the aqueous solution for adaptation is not particularly limited. However, when the nitrification tank (spare reservoir 31) is incorporated into the water purification treatment facility, part of the treated water is also passed through the reserve pond 31 to be treated water Ammonia (ion or salt) is added immediately before or after flowing into the reserve reservoir 31 to obtain an aqueous solution for adaptation.

  The aqueous solution for adaptation is passed through the reserve reservoir 31 or the aqueous solution for adaptation exceeding a certain amount is kept inside the reserve reservoir 31, the water temperature (10 to 35 ° C.) is maintained, and the ammonia nitrogen concentration is maintained Maintain a higher concentration than the water to be treated and perform accustomed culture. During the acclimatization culture, a normal adsorption treatment is performed in the activated carbon adsorption pond 25, but when the water temperature of the water to be treated is lowered (less than 20 ° C.), it is judged as the start timing of the nitrification step, manually or by mechanical means Stop the flow of the aqueous solution for adaptation or the supply of ammonia, and switch the flow of at least part of the water to be treated from the activated carbon adsorption reservoir 25 to the reserve reservoir 31.

  As the nitrification capacity of the reserve reservoir 31 is improved by the adaptation, the ammonia nitrogen concentration can be reduced even for low temperature, high concentration ammonia nitrogen treated water. In addition, it is also possible to perform the acclimatization process after performing the acclimatization process in the exterior of the preliminary pond 31, and filling the acclimatized nitrifying bacteria (carrier) into the preliminary pond 31 before the nitrification process.

  Two or more reserve reservoirs 31 may be installed. In this case, first, the nitrification process is performed in one or more reserve reservoirs 31. If the decrease in the nitrification capacity of the reserve reservoir 31 or a failure occurs, the other one If the flow of the treated water is switched to the reserve pond 31 or more, it is possible to continuously operate the water purification system for a longer time.

  Not only in the water purification treatment equipment of the first example, but also in the water purification treatment equipment of other examples, the activated carbon adsorption pond 25 (spare pond 31) whose organic substance adsorption capacity is reduced can be subjected to the regeneration treatment (activation treatment). For the activation treatment, it is possible to combine gas activation (steam, carbon dioxide, air, etc.), chemical activation (zinc chloride, sulfate, phosphate, etc.) or one or more of these activation treatments.

  More preferably, the activated carbon material taken out of the activated carbon adsorption reservoirs 25 and 31 is subjected to a steam activation treatment in which steam of high temperature (700 to 1000 ° C., preferably 800 to 950 ° C.) is brought into contact. The regenerated activated carbon material is packed in a container (column, tank) of the activated carbon adsorption reservoir 25 and reused. The activated carbon adsorption reservoir 31 (preliminary reservoir) regenerates the performance of the activated carbon material because it is burned in the water vapor activation process if the carrier is an organic substance even when carrying the nitrifying bacteria and also when containing the carrier other than the activated carbon material. It will not be degraded later.

  Therefore, it is preferable that the carrier as the reserve reservoir 31 is mainly composed of an activated carbon material itself or an organic substance such as a resin.

  In the first example, the reserve reservoir 31 of the activated carbon adsorption reservoir is a nitrated reservoir, but the present invention is not limited thereto. Below, the 2nd-5th example water purification treatment installation is also explained.

Second to fifth examples
FIGS. 2 to 5 show water purification treatment equipment of the second to fifth examples. In these water purification treatment equipment, in addition to the activated carbon adsorption pond (spare pond) 31, a nitrated pond 32 is installed.

  In the second example, the nitrification tank 32 is disposed between the raw water (water receiving well) and the coagulation sedimentation basin 11 (FIG. 2), and in the third example, is disposed downstream of the sand filtration pond 28 (FIG. 3) In the fourth example, it is installed between the coagulation sedimentation basin 10 and the ozone contact pond 21 (Fig. 4), and in the fifth example, it is installed between the activated carbon adsorption pond 25 and the sand filtration pond 28 (Fig. 5) .

  In any case, it is possible to manually or mechanically control the flow of the water to be treated by opening or closing a valve, and part or all of the water to be treated passes through the nitrification tank 32, or Treated at the water treatment facility without passing through 32 to become treated water.

  As in the case of the first example reservoir 31, nitrification bacteria (carriers) are accommodated in the nitrification ponds 32 to perform acclimation step, or nitrification bacteria (carriers) adapted outside the nitrification ponds 32 are added to the nitrification ponds 32. When the water temperature of the water to be treated becomes low, stop the water flow (supply of ammonia) of the aqueous solution for adaptation to the nitrification pond 32 and pass at least a part of the water to the nitrification pond 32. Start the nitrification process with water. As in the first example, also in the second to fifth examples, the residual concentration of ammonia nitrogen at low temperature can be suppressed by using the nitrifying bacteria obtained in the nitrification step.

  Thus, the installation location of the nitrification tank 32 is not limited, and the number of the nitrification ponds 32 is not limited, but when the microorganism (nitrifying bacteria) to be carried by the nitrification pond 32 is aerobic bacteria, ozone contact is made. It will be installed downstream or upstream of the pond 21.

  It is also possible to combine the nitrification ponds 32 shown in the first to fifth examples to perform nitrification treatment of the water to be treated in different treatment steps, and in this case, treatment can be conducted simultaneously to a plurality of nitrification ponds 32. Water may be passed through the water to perform nitrification treatment, or while one or more nitrification ponds 32 are used for nitrification treatment, the other one or more nitrification ponds 32 may be subjected to accommodative treatment .

<Others>
Although the aggregation settling basin 10, the ozone contact pond 21, the activated carbon adsorption pond 25 (31) and the sand filtration pond 28 are combined with the nitrification pond 32, the present invention is not limited to this.

  For example, the ozone contact pond 21 may be removed from the equipment shown in FIGS. 1 to 5 and a sand filter pond 28 may be installed between the activated carbon adsorption pond 25 and the coagulation settling pond 10. The aggregation settling basin 10, the sand filtration pond 28, the ozone contact pond 21, and the activated carbon adsorption pond 25 may be connected in the order described.

  Also in these water purification treatment facilities, the installation place and number of nitrate ponds 31, 32 are not particularly limited, and when only the activated carbon adsorption pond 25 is installed without installing the reserve pond 31 in the water purification treatment facility, Alternatively, the nitrification step may be performed by adding or replacing the separately adapted nitrifying bacteria (carrier) with the activated carbon material of the activated carbon adsorption reservoir 25.

  Furthermore, the immersion type molecular device 51 as shown in FIG. 6 may be installed in the inside of the coagulation sedimentation tank 10 or in the tank downstream of the coagulation sedimentation tank 10, as shown in FIG. The ceramic module type membrane separation apparatus 55 may be installed downstream of the coagulation sedimentation tank 10.

  In any of the examples, the nitrated pond 32 is any one of the upstream side of the flocculation settling basin 10, between the flocculation settling basin 10 and the membrane separation apparatus 51, 55, or downstream of the membrane separation apparatus 51, 55. It can be installed above.

  Hereinafter, examples of the present invention will be described together with comparative examples.

Comparative Example 1
In the same activated carbon adsorption pond 25 of the same water treatment equipment as in Fig. 1 except that the reserve pond 31 was removed, 0.2 mg / L of ammonium chloride as ammonia nitrogen in tap water dechlorinated in the same activated carbon adsorption pond 25; 300 mg of commercially available nitrifying liquid for aquarium The solution added so as to become / L was applied and conditioned for 1 week. Next, the temperature of the water to be treated for testing in which 10 mg / L of kaolin and 0.2 mg / L of ammonium chloride as ammoniacal nitrogen were added to the dechlorinated tap water was adjusted to 25 ° C., and the reserve reservoir 31 was removed; The same water purification equipment as in the above was used for continuous treatment with a throughput of 60 L / hr (water flow rate of 60 liters per hour), and the treated water after the 20th day of water flow initiation had 0.02 mg ammonia nitrogen in ammonia nitrogen It was less than. Furthermore, when the water temperature of the water to be treated was changed to 9 ° C from the 31st day, ammonia nitrogen in the treated water was detected from the 34th day (detected concentration or more), and 0.1 mg ammonia nitrogen on the 38th day It rose to / more than / L.

  After conditioning the activated carbon adsorption pond 25 under the same conditions as in Comparative Example 1, the treated water prepared under the same conditions as in Comparative Example 1 and having its water temperature adjusted is treated without passing through the reserve reservoir 31 in the water purification treatment facility of FIG. Continuous processing was performed at 60 L / hour. As in Comparative Example 1, the ammonia nitrogen of the treated water decreased to less than 0.02 mg / L from the 20th day after the start of water flow. However, in Example 1, in the reserve reservoir 31 which was conditioned under the same conditions as the activated carbon adsorption reservoir 25 while treating the water to be treated, the water temperature was 25 ° C., the ammoniacal nitrogen concentration was 1 mg / L, and dissolved oxygen Conditioned culture was performed with the aqueous solution for adjustment maintained at 6 mg / L or more. Thereafter, the temperature of the water to be treated was changed to 9 ° C. on the 31st day from the start of the test, and the activated carbon adsorption reservoir 25 was switched to the reserve reservoir 31 to pass water. It was maintained at less than 0.02 mg / L.

  Conditioned culture was carried out under the same conditions as Example 1 except that the ammoniacal nitrogen concentration of the aqueous solution for conditioning was changed to 5 mg / L, and the ammonia nitrogen concentration of the water to be treated on day 31 and thereafter was increased to 2 mg / L. When the nitrification treatment in the reserve reservoir 32 was performed under the same conditions as in Example 1 except for the above, the ammoniacal nitrogen concentration was maintained at less than 0.02 mg / L even on the 60th day.

  Under the same conditions as Example 1 and Comparative Example 1 except that ammonium chloride was added at 1 mg / L as ammonia nitrogen, preconditioning of the activated carbon adsorption reservoir and water to be treated were prepared. The water to be treated was adjusted to a water temperature of 25 ° C. and continuously treated at a treatment amount of 60 L / hour without passing through the nitrification tank 32 in the water purification treatment facility of FIG. The ammonia nitrogen of water became less than 0.02 mg / L.

  On the other hand, nitrated pond 32 is filled with crushed natural zeolite as a carrier, conditioned under the same conditions as activated carbon adsorption pond, and treated with a system that does not go through nitrated pond 32, water temperature 30 ° C, ammonia nitrogen Conditioned culture was carried out with an aqueous solution for adjustment adjusted to 10 mg / L and 6 mg / L or more of dissolved oxygen. Then, from the 31st day, the water temperature of the water to be treated was changed to 8 ° C., the ammoniacal nitrogen concentration was changed to 3 mg / L, and the system was switched to the system via the nitrification tank 32 to pass water. Nitrogen remained below 0.02 mg / L.

  Under the same conditions as in Example 1 and Comparative Example 1, treated water for preconditioning and testing of the activated carbon adsorption pool was prepared. The water to be treated was adjusted to a water temperature of 25 ° C. and continuously treated with the treatment amount of 60 L / hour) without passing through the nitrification tank 32 in the water purification treatment facility of FIG. The ammonia nitrogen of treated water decreased to less than 0.02 mg / L.

  On the other hand, the nitrated pond 32 is filled with granular activated carbon as a carrier and conditioned under the same conditions as the activated carbon adsorption pond of Example 1, and the water temperature is 25 ° C., the ammoniacal nitrogen concentration is 5 mg / L, and dissolved oxygen is 6 mg / L or more Conditioned culture was carried out with the aqueous solution for adaptation kept. In addition, when the water temperature of the water to be treated was changed to 9 ° C and the ammoniacal nitrogen concentration was changed to 2 mg / L from the 31st day, the system was switched to a system via the nitrification tank 32 and water flowed. Nitrogen remained below 0.02 mg / L.

  The pretreatment water for the activated carbon adsorption pond and the test for treatment similar to those of Example 1 and Comparative Example 1 were produced except that the ammoniacal nitrogen concentration of the water to be treated was changed to 0.5 mg / L. The water to be treated was adjusted to a water temperature of 25 ° C. and treated continuously at a treatment amount of 60 L / hour without passing through the nitrification tank 32 in the water purification treatment facility of FIG. Ammonia nitrogen was less than 0.02 mg / L.

  The nitrification tank 32 is filled with polyvinyl alcohol gel as a carrier and conditioned under the same conditions as the activated carbon adsorption tank of Example 1, and the water temperature is 30 ° C., the ammoniacal nitrogen concentration is 10 mg / L, and dissolved oxygen is 6 mg / L or more Conditioned culture was carried out with the aqueous solution for adaptation kept. Then, from the 31st day, the water temperature of the water to be treated was changed to 9 ° C, the ammoniacal nitrogen concentration was changed to 2 mg / L, and the system was switched to a system via the nitrification tank 32 and water flowed. The ammoniacal nitrogen concentration of the water remained below 0.02 mg / L.

  Under the same conditions as in Example 5, preconditioning of the activated carbon adsorption pond and water to be treated were prepared. Next, the water temperature was adjusted to 25 ° C, and continuous treatment (throughput 60 L / hour) of the system not passing through the nitrification tank 32 was performed with the water purification treatment equipment of FIG. Nitrogen decreased to less than 0.02 mg / L.

  During this time, water temperature 30 ° C, powdered activated carbon 100 mg / L, ammonia nitrogen 10 mg / L, aquarium nitrifying bacteria drug 300 mg / L, dissolved oxygen 6 mg / L or more Conditioned culture of nitrifying bacteria / nitrifying bacteria Further, a granular gel in which this culture solution was covered with a polyethylene glycol dimetallate polymer gel was prepared and filled in a nitrated pond 32.

  Then, from the 31st day, the water temperature of the water to be treated was changed to 9 ° C., and the ammoniacal nitrogen concentration was changed to 2 mg / L, and the water to be treated was passed through the nitrated pond 32 filled with gel. However, the ammoniacal nitrogen concentration of the treated water remained below 0.02 mg / L.

  What provided two reserve ponds 31 (two ponds) in the water purification treatment equipment of FIG. 1 was prepared, and preconditioning and treated water of an activated carbon adsorption pond and a reserve pond were produced on the same conditions as Example 1. Subsequently, the water temperature was adjusted to 25 ° C., and continuous treatment was performed at a throughput of 60 L / hour under the same conditions as in Example 1 without passing through any reserve reservoir 31. Nitrogen decreased to less than 0.02 mg / L.

  Of the two reserve reservoirs 31, the first reserve reservoir 31 is acclimated with the aqueous solution for adaptation adapted to maintain the water temperature 25 ° C., ammonia nitrogen 1 mg / L, dissolved oxygen 6 mg / L or more, and the second reserve The pond 31 was subjected to acclimatization culture with a conditioning aqueous solution maintained at a water temperature of 25 ° C., ammonia nitrogen 10 mg / L, and dissolved oxygen 6 mg / L or more.

  Next, from the 31st day, the water temperature of the water to be treated was changed to 9 ° C, the ammoniacal nitrogen was changed to 2mg / L, and the activated carbon adsorption reservoir 25 was switched to the first reserve reservoir 31 to pass water. The ammoniacal nitrogen concentration of the treated water remained below 0.02 mg / L. Furthermore, from the 61st day, the water temperature of the water to be treated is changed to 7 ° C., the ammoniacal nitrogen concentration is changed to 3 mg / L, and the flow of the water to be treated is switched from the first reserve reservoir 31 to the second reserve reservoir 32 As a result, even at the 120th day, the ammoniacal nitrogen concentration of the treated water remained below 0.02 mg / L.

  10: Coagulation settling basin, 21: ozone contact pond, 25: activated carbon adsorption pond, 28: sand filtration pond, 31: reserve pond, 32: nitrification pond

Claims (10)

An operation management method of a water purification system for nitrifying ammonium ions contained in water to be treated with nitrifying bacteria,
An adapting step of adapting the nitrifying bacteria with an adapting aqueous solution having a water temperature of 10 ° C. to 35 ° C. and containing ammonium ions having a higher concentration than the water to be treated;
A nitrification step of bringing the water to be treated whose water temperature has dropped below 20 ° C. into contact with the acclimatized nitrifying bacteria;
I have a,
A coagulation sedimentation basin where the water purification treatment facility coagulates and precipitates by adding a coagulant to treated water, an ozone contact pond where ozone is brought into contact with treated water, and an activated carbon adsorption pond where activated water adsorption treatment of treated water is performed; And a filtration pond for filtering the water to be treated;
A nitrification tank carrying the nitrifying bacteria is installed at least upstream of the coagulation sedimentation tank,
A method for operation management comprising: performing nitrification steps by bringing water to be treated prior to aggregation and precipitation into contact with nitrifying bacteria after the step of becoming familiar . An operation management method of a water purification system for nitrifying ammonium ions contained in water to be treated with nitrifying bacteria,
An adapting step of adapting the nitrifying bacteria with an adapting aqueous solution having a water temperature of 10 ° C. to 35 ° C. and containing ammonium ions having a higher concentration than the water to be treated;
A nitrification step of bringing the water to be treated whose water temperature has dropped below 20 ° C. into contact with the acclimatized nitrifying bacteria;
I have a,
A coagulation sedimentation basin where the water purification treatment facility coagulates and precipitates by adding a coagulant to treated water, an ozone contact pond where ozone is brought into contact with treated water, and an activated carbon adsorption pond where activated water adsorption treatment of treated water is performed; And a filtration pond for filtering the water to be treated;
A nitrification pond supporting the nitrifying bacteria is installed on either or both of the upstream side and the downstream side of the filtration pond,
A method of operation management comprising: carrying out a nitrification step by bringing the nitrifying bacteria after the acclimatization step into contact with either or both of the treated water before and / or after the filtration treatment . An operation management method of a water purification system for nitrifying ammonium ions contained in water to be treated with nitrifying bacteria,
An adapting step of adapting the nitrifying bacteria with an adapting aqueous solution having a water temperature of 10 ° C. to 35 ° C. and containing ammonium ions having a higher concentration than the water to be treated;
A nitrification step of bringing the water to be treated whose water temperature has dropped below 20 ° C. into contact with the acclimatized nitrifying bacteria;
I have a,
A coagulation sedimentation basin where the water purification treatment facility coagulates and precipitates by adding a coagulant to treated water, an ozone contact pond where ozone is brought into contact with treated water, and an activated carbon adsorption pond where activated water adsorption treatment of treated water is performed; And a filtration pond for filtering the water to be treated;
A nitrification pond supporting the nitrifying bacteria is installed at least between the coagulation sedimentation basin and the ozone contact pond,
An operation management method characterized by performing the above-mentioned nitrification step by bringing the water to be treated which is after coagulation / sedimentation treatment and before ozone contact into contact with the nitrifying bacteria after the adaptation step . The operation control method according to any one of claims 1 to 3, wherein the concentration of ammonium nitrogen in the aqueous solution for adaptation is 1 mg / L or more and 30 mg / L or less. Add a flocculant to the water to be treated to coagulate and precipitate it, an ozone contact tank to make ozone contact with the water to be treated, an activated carbon adsorption tank to treat the water to be treated with activated carbon, and filter the water to be treated A method of operating and managing a water purification system having a filtration pond,
The operation management method according to any one of claims 1 to 4 , wherein the nitrifying bacteria are supported on at least one of the activated carbon adsorption ponds, the nitrifying bacteria are brought into contact with the water to be treated, and a nitrification step is performed. The operation management method according to claim 5 , wherein the acclimatization step is performed in one or both of the outside of the activated carbon adsorption reservoir and the inside of the activated carbon adsorption reservoir. Install multiple activated carbon adsorption ponds,
Make one or more activated carbon adsorption ponds a reserve pond to carry the nitrifying bacteria,
Adsorb treatment of treated water with one or more other activated carbon adsorption ponds,
Wherein when the water temperature of the water to be treated is lowered below a predetermined temperature, the water flow of the water to be treated is switched to the preliminary pond from activated carbon adsorption pond performing adsorption treatment, claim 5 or claim performing nitrification step 6 Operation management method described in. Measuring either one or both of the ammonium ion concentration and the water temperature of the water to be treated;
The operation management method according to any one of claims 1 to 7 , wherein either or both of the ammonium ion concentration of the aqueous solution and the start time of the nitrification step are controlled based on the measured data. The operation according to any one of claims 5 to 8 , further comprising a regeneration step of regenerating either one or both of the activated carbon adsorption pool having a reduced organic substance adsorption capacity and the nitrification pool having a reduced nitrification capacity. Management method. The operation management method according to any one of claims 1 to 9 , further comprising the step of chlorinating the water to be treated after the nitrification step.

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