JP5210787B2 - Water treatment apparatus and water treatment method - Google Patents

Description

  The present invention relates to a water treatment apparatus and a water treatment method for purifying ammonia, iron, and manganese contained in water to be treated.

  Conventionally, in water purification treatment, industrial water treatment, sewage treatment, wastewater treatment, and the like, biological treatment methods for removing contaminants in water to be treated using the action of microorganisms have been used. This biological treatment method is widely used for the treatment of organic matter and ammonia, etc., but is also used for the removal or oxidation of iron, manganese and the like. For example, biological filtration is used to remove or oxidize ammonia, iron, and manganese in groundwater and river water.

  Here, as an apparatus for purifying ammonia, iron, and manganese contained in treated water using biological filtration, for example, Patent Document 1 discloses biological filtration that biologically filters treated water supplied from a landing well. There has been proposed a water treatment apparatus including an apparatus and a solid-liquid separation apparatus that adds a PAC, a chlorine agent, or the like to treated water discharged from a biological filtration apparatus and performs a solid-liquid separation treatment. According to the apparatus of Patent Document 1, a biological carrier (filter material) to which microorganisms adhere by oxidation of ammonia, iron and manganese in water to be treated by the action of microorganisms such as iron bacteria and nitrifying bacteria in a biological filtration apparatus. On top, oxidation and insolubilized iron and manganese are captured. Moreover, PAC, a chlorine agent, etc. are added to the treated water discharged | emitted from a biological filtration apparatus, and iron, manganese, etc. which remain | survive in treated water are removed with a solid-liquid separator. Then, for the purpose of sterilization treatment, a chlorinating agent is added to the treated water obtained from the solid-liquid separator to obtain the final treated water.

  However, if the operation of the biological filtration apparatus is continued, the adhesion amount of impurities such as iron and manganese increases, and the water passage space of the biological carrier (filter material) decreases. Therefore, in order to secure a water passage space for the biological carrier, it is necessary to periodically perform so-called reverse water washing in which washing water (back water) flows in the opposite direction to the flow of the water to be treated to wash the biological carrier. There is.

  Conventionally, it has been thought that when backflow water washing is performed with water containing a chlorinating agent, microorganisms attached to the biological carrier are sterilized by the chlorinating agent and the biological activity as a biological filtration device is reduced. Therefore, conventionally, final treated water containing a chlorine agent is not used as washing water, for example, as in the device of Patent Document 1, a storage tank is provided for storing treated water discharged from a biological filtration device, The biological carrier was backwashed with treated water in the storage tank (containing no chlorine agent).

JP 2005-288417 A

  However, the present inventors have found that microorganisms that remove or oxidize ammonia, iron, and manganese are biologically active as long as the chlorinating agent concentration is within a predetermined range, specifically, water with a residual free chlorine concentration within a predetermined range. It has been found that it is not sterilized enough to decrease. The present invention has been made based on such knowledge. That is, an object of the present invention is to eliminate the need for a storage tank for storing treated water discharged from a biological filtration device, which has been conventionally required, in order to perform reverse flow water washing of a biological carrier with water containing no chlorine agent. An object of the present invention is to provide a water treatment apparatus and a water treatment method capable of performing back-flow water washing of a biological carrier even with water after addition of a chlorine agent.

  The water treatment device of the present invention performs solid-liquid separation on a biological filtration device provided with a biological carrier for removing or oxidizing ammonia, iron and manganese in water to be treated, and biological treatment water discharged from the biological filtration device. A chlorinating agent that adds a chlorinating agent to at least one of a solid-liquid separation device provided with a filter medium, biological treatment water discharged from the biological filtration device, and solid-liquid separation treatment water discharged from the solid-liquid separation device An addition means; and a backflow water cleaning means for supplying the biological liquid filtration device with the chlorinating agent-containing solid-liquid separation treated water and performing a backflow water cleaning of the biological carrier. The chlorine agent is added so that the residual free chlorine concentration of the solid-liquid treated water containing the chlorine agent supplied to the filtration device is 0.1 mg / L to 1.0 mg / L.

  Moreover, the water treatment apparatus of the present invention comprises a biological filtration apparatus provided with a biological carrier for removing or oxidizing ammonia, iron and manganese in water to be treated, and biological treatment water discharged from the biological filtration apparatus as a solid liquid. A chlorine agent is added to at least one of a solid-liquid separation device including a filter medium to be separated, biological treatment water discharged from the biological filtration device, and solid-liquid separation treatment water discharged from the solid-liquid separation device. A chlorinating agent adding means; and a backflow water cleaning means for supplying the chlorinating agent-containing solid-liquid separation treated water to the biological filtration device and performing a reverse water cleaning of the biological carrier. Chlorine neutralizer addition means for adding a chlorine neutralizer to the chlorine-containing solid-liquid separation treated water, the residual free chlorine concentration of the chlorine-containing solid-liquid separation treated water supplied to the biological filtration device, 0.1 mg / L to 1.0 m As a / L is added chlorine neutralizer.

  Moreover, the water treatment apparatus of the present invention comprises a biological filtration apparatus provided with a biological carrier for removing or oxidizing ammonia, iron and manganese in water to be treated, and biological treatment water discharged from the biological filtration apparatus as a solid liquid. A chlorine agent is added to at least one of a solid-liquid separation device including a filter medium to be separated, biological treatment water discharged from the biological filtration device, and solid-liquid separation treatment water discharged from the solid-liquid separation device. A chlorinating agent adding means; and a backflow water washing means for feeding the chlorinating agent-containing solid-liquid separation treated water to the biological filtration device and washing the biological carrier with a reverse flow water, wherein a plurality of the biological filtration devices are provided. The backflow water cleaning means is a part of the biologically treated water discharged from the biological filtration device that does not perform the backflow water cleaning to the solid-liquid separation treated water containing the chlorine agent supplied to the biological filtration device that performs the backflow water cleaning. Processing to add The biological treatment is performed so that the residual free chlorine concentration of the solid-liquid separation treatment water containing the chlorinating agent supplied to the biological filtration apparatus that includes the addition means and performs the backflow water cleaning is 0.1 mg / L to 1.0 mg / L. Add water.

  Further, in the water treatment apparatus, the backflow water washing means is in a range of 2 to 5 times the volume of the biological carrier after supplying the water to be treated to the biological filtration apparatus in an amount of 100 times or more the volume of the biological carrier. Preferably, the chlorinating agent-containing solid-liquid separation treated water is supplied to the biological filtration device, and the biological carrier is washed with a backflow water.

  Moreover, in the water treatment apparatus, it is preferable that the backflow water cleaning means supplies the chlorine-containing solid-liquid separation treated water to the solid-liquid separation treatment apparatus to perform backflow water washing of the filter medium.

  Further, the water treatment method of the present invention includes a biological filtration step for removing or oxidizing ammonia, iron and manganese in water to be treated with a biological carrier, and solid-liquid separation for solid-liquid separation of biologically treated water obtained from the biological filtration step. A chlorinating agent adding step of adding a chlorinating agent to at least one of the step, the biologically treated water obtained from the biological filtration step, the solid-liquid separation treating water obtained from the solid-liquid separation step, and the chlorinating agent-containing step And a backflow water washing step of washing the biological carrier with backflow water using solid / liquid separation treated water. In the chlorine agent addition step, the residual free chlorine concentration of the chlorine-containing solid-liquid separation treated water is 0. A chlorine agent is added so that it may become 1 mg / L-1.0 mg / L.

  Further, the water treatment method of the present invention includes a biological filtration step for removing or oxidizing ammonia, iron and manganese in water to be treated with a biological carrier, and solid-liquid separation for solid-liquid separation of biologically treated water obtained from the biological filtration step. A chlorinating agent adding step of adding a chlorinating agent to at least one of the step, the biologically treated water obtained from the biological filtration step, the solid-liquid separation treating water obtained from the solid-liquid separation step, and the chlorinating agent-containing step A backflow water washing step of washing back the biological carrier with solid-liquid separation treated water, and in the backflow water washing step, a chlorine neutralizer is added to the chlorine-containing solid-liquid separation treated water, The residual free chlorine concentration of the chlorinating agent-containing solid-liquid separation treated water is set to 0.1 mg / L to 1.0 mg / L.

Further, the water treatment method of the present invention includes a biological filtration step for removing or oxidizing ammonia, iron and manganese in water to be treated with a biological carrier, and solid-liquid separation for solid-liquid separation of biologically treated water obtained from the biological filtration step. A chlorinating agent adding step of adding a chlorinating agent to at least one of the step, the biologically treated water obtained from the biological filtration step, the solid-liquid separation treating water obtained from the solid-liquid separation step, and the chlorinating agent-containing step And a backflow water washing step for washing the biological carrier with the backflow water using solid-liquid separation treated water, and a plurality of biological filtration devices equipped with the biological carrier are provided. In the backflow water washing step, carrier to a solid-liquid separation treatment water containing chlorine agent supplied to the biological filtration device comprising a, was added a portion of the biologically treated water discharged from the biological filtration apparatus including a biological carrier is not performed backflow water washing, before The residual free chlorine concentration of solid-liquid separation treatment water chlorine-containing and 0.1mg / L~1.0mg / L.

  Further, in the water treatment method, in the backflow water washing step, after the treated water is supplied to the biological carrier in an amount of 100 times or more the biological carrier volume, the biological carrier volume is in a range of 2 to 5 times the biological carrier volume. It is preferable that the chlorinating agent-containing solid-liquid separation treated water is supplied to the biological carrier and the biological carrier is back-washed.

  According to the present invention, in order to perform reverse flow water washing of a biological carrier with water containing no chlorinating agent, a storage tank for storing treated water discharged from a biological filtration device, which has been conventionally required, is unnecessary, and chlorine The biological carrier can be washed back-water with water after the addition of the agent.

  Embodiments of the present invention will be described below. This embodiment is an example for carrying out the present invention, and the present invention is not limited to this embodiment.

  FIG. 1 is a schematic diagram illustrating an example of a configuration of a water treatment device according to the present embodiment. As shown in FIG. 1, the water treatment device 1 includes a landing well 12 that stores well water (treated water) pumped up by a well pump 10, a biological filtration device 14, a solid-liquid separation device 16, and a chlorinating agent addition device 18. The backflow water cleaning device 20 is provided. Moreover, the receiving well 12 and the biological filtration apparatus 14, the biological filtration apparatus 14 and the solid-liquid separation apparatus 16, and the solid-liquid separation apparatus 16 and the backflow water washing apparatus 20 are connected by piping 22a, 22b, and 22c, respectively. The landing well 12 shown in FIG. 1 is a fountain type aeration type, but is not necessarily limited thereto.

  In the main body part 14a of the biological filtration device 14, a filter layer 14b filled with a biological carrier (filter medium) to which microorganisms adhere is formed. A mesh 14c is installed above the filter layer 14b. The net | network 14c is for preventing that the biological carrier which comprises the filter layer 14b at the time of backflow water washing | cleaning flows out. Further, an air pipe 26 provided with a blower 24 is connected to the main body portion 14a on the lower side of the filter layer 14b, so that air from the blower 24 is jetted toward the filter layer 14b. Air cleaning can be performed together with water cleaning.

  The biological carrier constituting the filter layer 14b is not particularly limited as long as it is a carrier to which microorganisms such as nitrifying bacteria, manganese-oxidizing bacteria, and iron bacteria adhere, but for example, excellent adhesion and retention of microorganisms. Polyester fiber filter media, ceramic pellets, polypropylene cylindrical filter media, and the like are used.

  A main body portion 14a below the filter layer 14b is provided with a treated water discharge port (not shown) for discharging the treated water that has passed through the filter layer 14b (sometimes referred to as biologically treated water in this specification). One end of the pipe 22b is connected to the treated water discharge port. Moreover, the valve 28 is connected to the piping 22b, and the amount of treated water discharged from the biological filtration device 14 is adjusted by adjusting the opening degree of the valve 28, and the water level in the main body 14a is adjusted. The

  A filter layer 16b filled with a filter medium for solid-liquid separation of biologically treated water is formed in the main body portion 16a of the solid-liquid separator 16 (rapid filtration pond). The main body portion 16a on the upper side of the filter layer 16b is provided with a treated water supply port (not shown) through which biological treated water is introduced, and the other end (opposite side of the biological filtration device 14) of the pipe 22b is treated. Connected to the water supply port. The solid-liquid separator 16 includes a flocculant tank 30, a flocculant addition pump 32, and a flocculant inflow pipe 34. The flocculant inflow pipe 34 is connected to the pipe 22b from the flocculant tank 30. As a filter medium used for the solid-liquid separator 16, for example, silica sand, anthracite, manganese sand and the like are used. Further, as the flocculant accommodated in the flocculant tank 30, for example, an inorganic flocculant such as polyaluminum chloride or aluminum sulfate, an organic polymer flocculant such as an anionic polymer, or the like is used.

  A treated water discharge port for discharging treated water (which may be referred to as solid-liquid separated treated water in this specification) that has passed through the filtered layer 16b is provided in the main body portion 16a on the lower side of the filtered layer 16b of the solid-liquid separator 16. Is provided, and one end of the pipe 22c is connected to the treated water discharge port. Further, a valve 36 is connected to the pipe 22c, and the amount of treated water discharged from the solid-liquid separator 16 is adjusted by adjusting the opening of the valve 36, and the water level in the main body 16a is adjusted. Is done.

  The chlorine agent adding device 18 will be described. The chlorine agent addition device 18 includes a chlorine agent tank 38, a chlorine agent addition pump 40, a residual free chlorine concentration meter 42, and a chlorine agent inflow pipe 44. In order to add the chlorinating agent to the solid / liquid separation treated water, the chlorinating agent inflow pipe 44 is connected to a pipe 22c through which the solid / liquid separating treatment water flows from the chlorinating agent tank 38. The chlorine agent stored in the chlorine agent tank 38 is not particularly limited as long as it has a bactericidal action in order to ensure the safety of the finally obtained treated water (solid-liquid separation treated water). However, for example, sodium hypochlorite or the like is used.

  In the present embodiment, the residual free chlorine concentration meter 42 is installed in the storage tank 45 of the backflow water cleaning device 20, and solid-liquid separation is performed while measuring the residual free chlorine concentration in the solid-liquid separation treated water used for backflow water cleaning. You may control the addition amount of a chlorine agent so that the residual free chlorine density | concentration in treated water may become an appropriate concentration range. Here, the appropriate range of the residual free chlorine concentration in the solid-liquid separation treated water is the upper limit of the residual free chlorine concentration at which the microorganisms in the biological filtration device 14 are sterilized and the biological activity does not decrease when washing with backflow water is performed. Moreover, when used as tap water or the like, the lower limit is the residual free chlorine concentration value that can ensure the safety of water. In practice, the chlorine agent is added so that the residual free chlorine concentration in the solid-liquid separation treated water is in the range of 0.1 mg / L to 1.0 mg / L.

  In the present embodiment, when the flow rate of the solid-liquid separation treated water discharged from the solid-liquid separation device 16 fluctuates, a residual free chlorine concentration meter 42 is installed, and chlorine is measured based on the measured residual free chlorine concentration. It is preferable to control the addition amount of the agent, but if the flow rate of the solid-liquid separation treated water is constant, a certain amount of chlorine is used so that the residual free chlorine concentration in the solid-liquid separation treated water falls within an appropriate concentration range. Since the agent may be added, the residual free chlorine concentration meter 42 is not necessarily installed.

  Moreover, in this embodiment, since a chlorine agent should just be added so that the residual free chlorine density | concentration in solid-liquid separation processing water may be in the range of 0.1 mg / L-1.0 mg / L, from solid-liquid separation apparatus 16 A chlorine agent may be added to one of the solid-liquid separation treated water discharged and the biological treated water discharged from the biological filtration device 14. That is, it is only necessary that at least one of the piping 22c through which the chlorinating agent tank 38 and the solid-liquid separation treated water flow and the piping 22b through which the chlorinating agent tank 38 and the biological treatment water flow are connected by the chlorinating agent inflow pipe 44. When a chlorinating agent is added to biologically treated water, the chlorinating agent also functions as an oxidizing agent that oxidizes manganese remaining in the biologically treated water, so that the treatment efficiency of the solid-liquid separation treatment can be improved. The residual free chlorine concentration in the separation treated water is lower than the residual free chlorine concentration in the biological treated water. Therefore, when adding a chlorinating agent only to biologically treated water, increase the amount of the chlorinating agent so that the residual free chlorine concentration in the finally obtained solid-liquid separation treated water falls within the appropriate concentration range. There is a need.

  The backflow water cleaning device 20 will be described. The backflow water cleaning device 20 includes a storage tank 45, a backflow water pump 46, and a backflow water inflow pipe 48. The storage tank 45 is provided with a treated water supply port (not shown) through which solid-liquid separated treated water to which a chlorinating agent is added (sometimes referred to as backflow water in the specification) is introduced, and the piping 22c. The other end (the opposite side of the solid-liquid separator 16) is connected to the treated water supply port. In addition, in order to wash back the biological carrier of the biological filtration device 14 and the filter medium of the solid-liquid separation device 16, the backward flow water inflow pipe 48 is connected to the biological filtration device 14 from the backward flow water discharge port (not shown) of the storage tank 45. The main body part 14a on the lower side of the filter layer 14b and the pipe 22c communicating with the treated water discharge port of the solid-liquid separator 16 are connected.

  Although not shown, a treated water outlet pipe is connected to either the storage tank 45 or the pipe 22c, and final treated water is obtained from the treated water outlet pipe.

  Next, the operation method of the water treatment apparatus of this embodiment will be described. The treated water pumped up by operating the well pump 10 is temporarily stored in the landing well 12, and then the treated water is supplied to the biological filtration device 14 by a raw water pump or natural flow. At that time, oxygen in the atmosphere is supplied into the water to be treated. When the water to be treated in the biological filtration apparatus 14 passes through the filter layer 14b, it is treated by microorganisms such as nitrifying bacteria, manganese-oxidizing bacteria, and iron bacteria that adhere (grow) on the biological carrier constituting the filter layer 14b. Ammonia, iron, and manganese in water are oxidized, and iron, manganese, and the like that have been insolubilized by oxidation are captured by the biological carrier (biological filtration step).

  The biologically treated water that has passed through the filter layer 14b is supplied to the solid-liquid separator 16 through the pipe 22b. When the biologically treated water is supplied to the main body 16a of the solid-liquid separator 16, the flocculant addition pump 32 is operated to add the flocculant to the biologically treated water. Then, iron, manganese, etc. remaining in the treated water are removed by the filter layer 16b of the solid-liquid separator 16 (solid-liquid separation step). The solid-liquid separation treated water that has passed through the filter layer 16b is supplied to the storage tank 45 through the pipe 22c. When the solid-liquid separation treated water is supplied to the storage tank 45, the chlorinating agent addition pump 40 is operated, and the residual free chlorine concentration in the solid-liquid separation treated water is in the range of 0.1 mg / L to 1.0 mg / L. Then, a chlorine agent is added to the solid-liquid separation treated water (chlorine agent addition step). And it becomes possible to take out the treated water (final treated water) from which ammonia, iron, and manganese were oxidized and removed from the treated water extraction pipe (not shown).

  In addition, when washing back water, the back water pump 46 is operated, the valves 28 and 36 of the pipes 22b and 22c are closed, the valves 50a and 50b of the back water inlet pipe 48 are opened, and a chlorine agent is added. The solid-liquid separation treated water is supplied from the backflow water inflow pipe 48 to the biological filtration device 14 and the solid-liquid separation device 16. The backflow water supplied to the biological filtration device 14 and the solid-liquid separation device 16 passes through the filter layers 14b and 16b in the direction opposite to the flow of the water to be treated, and the biological carrier and the filter medium are washed (backflow water washing step). ). The backflow water that has passed through the filter layers 14b and 16b is discharged from above the filter layers 14b and 16b, respectively.

  In this embodiment, the water to be treated is supplied to the biological filtration device 14 in an amount of 100 times the volume of the biological carrier packed in the filter layer 14b (water is passed through the filter layer 14b), and then the solid agent to which the chlorine agent is added. It is preferable that liquid separation treated water is supplied to the biological filtration device 14 (supplied to the filter layer 14b) in a range of 2 to 5 times the volume of the biological carrier, and the biological carrier is washed with countercurrent water. Such a method of washing backflow water is preferably performed by installing a flow meter in the pipe 22b and the backflow water inflow pipe 48 and managing the flow rate. In addition, this backflow water cleaning method can be suitably applied to a water treatment apparatus and the like which will be described later. If the backflow water washing is performed before supplying the water to be treated to the biological filtration device 14 at a volume of 100 times or more of the capacity of the biological carrier, the microorganisms attached to the biological carrier are sterilized, and the biological activity after the backwater washing is reduced. There is a case. In addition, if the solid-liquid separation treated water to which the chlorine agent is added is supplied to the biological filtration device 14 in an amount less than twice the volume of the biological carrier, the cleaning effect may not be sufficiently exhibited. In addition, if solid-liquid separation treated water to which a chlorinating agent is added is supplied to the biological filtration device 14 in an amount exceeding 5 times the volume of the biological carrier, the microorganisms attached to the biological carrier are sterilized, and the biological activity after washing with backflow water decreases. There is a case. In addition, it is preferable to perform the backflow water washing | cleaning of the solid-liquid separator 16 similarly.

  FIG. 2 is a schematic diagram illustrating an example of a configuration of a water treatment device according to another embodiment of the present invention. In the water treatment apparatus 2 shown in FIG. 2, the same reference numerals are given to the same configurations of the water treatment apparatus 1 shown in FIG. 1, and the description thereof is omitted.

  In the present embodiment, in the chlorinating agent addition device 18 of the water treatment apparatus shown in FIG. 2, the residual free chlorine concentration in the solid-liquid separation treated water is in the range of 0.1 mg / L to 1.0 mg / L. It is not necessary to add a chlorine agent to the solid-liquid separation treated water. For example, the chlorine agent adding device 18 may add a chlorine agent to the solid-liquid separation treated water so that the residual free chlorine concentration in the solid-liquid separation treated water exceeds 1.0 mg / L. This is because, in the present embodiment, in the backflow water cleaning device 20 described later, the residual free chlorine concentration in the solid-liquid separation treated water supplied to the biological filtration device 14 (and the solid-liquid separation device 16) is 0.1 mg / L to This is because a chlorine agent is added so as to be in the range of 1.0 mg / L, and chlorine neutralization is performed.

  The backflow water cleaning apparatus 20 of the water treatment apparatus 2 shown in FIG. 2 will be described. As shown in FIG. 2, the backflow water cleaning device 20 includes a chlorine neutralizer supply device 52 in addition to the configuration shown in FIG. 1. The chlorine neutralizer supply device 52 includes a chlorine neutralizer tank 54, a chlorine neutralizer pump 56, and a chlorine neutralizer inflow pipe 58. The chlorine neutralizer inflow pipe 58 is connected from the chlorine neutralizer tank 54 to the backflow water inflow pipe 48. The chlorine neutralizer stored in the chlorine neutralizer tank 54 is not particularly limited as long as it can neutralize free chlorine. For example, sodium thiosulfate, sodium sulfite, etc. are used. It is done.

  In the present embodiment, for example, when the chlorine agent is added by the chlorine agent addition device 18 so that the residual free chlorine concentration in the solid-liquid separation treated water exceeds 1.0 mg / L, the backflow water pump 46, the chlorine neutralizer pump 56 is operated, and the residual free chlorine concentration in the backflow water passing through the backflow water inflow pipe 48 is 0.1 mg / L to 1.0 mg / L. To neutralize the chlorine. And this is utilized for backflow water washing.

  If the residual chlorine concentration in the solid-liquid separation treated water in the storage tank 45 is constant, the residual free chlorine concentration in the solid-liquid separation treated water passing through the backflow water inflow pipe 48 is in the range of 0.1 mg / L to 1.0 mg / L. A certain amount of chlorine neutralizing agent may be supplied so that However, when the residual chlorine concentration in the solid-liquid separation treated water in the storage tank 45 fluctuates, the chlorine neutralizer pump is based on the residual free chlorine concentration value of the residual free chlorine concentration meter installed in the storage tank 45. It is preferable to control the operation of 56 and adjust the addition amount of the chlorine neutralizing agent.

  Moreover, in this embodiment, for example, the residual free chlorine concentration in the finally obtained water is set to a relatively high concentration of 0.8 mg / L to 1.0 mg / L or less, but the backflow water cleaning is performed. As a method for adding the chlorine neutralizing agent even when it is preferable to set the concentration lower than the above concentration in terms of the capacity of the biological carrier, etc. (that is, 0.1 mg / L to 0.8 mg / L or less). It is preferable to apply.

  FIG. 3 is a schematic diagram illustrating an example of a configuration of a water treatment device according to another embodiment of the present invention. In the water treatment device 3 of FIG. 3, the same reference numerals are given to the same configurations as the water treatment devices 1 and 2 shown in FIGS. 1 and 2, and the description thereof is omitted.

  In the present embodiment, similarly to the water treatment apparatus shown in FIG. 2, in the chlorinating agent addition apparatus 18 shown in FIG. 3, the residual free chlorine concentration in the solid-liquid separation treated water is 0.1 mg / L to 1.0 mg / L. Therefore, it is not necessary to add a chlorinating agent to the solid-liquid separation treated water.

  In the present embodiment, as shown in FIG. 3, a plurality of biological filtration devices 15a and 15b are provided.

The backflow water cleaning device 20 shown in FIG. 3 will be described. The backflow water cleaning device 20 includes treated water addition lines 60a and 60b in addition to the configuration shown in FIG. To add the biologically treated water discharged from the biological filtration device 15a or 15b to the reflux water inlet pipe 48, treated water addition line 60a, 60b is connected from the pipe _22b 1, 22b ₂ backflow water inlet pipe 48.

Backflow water cleaning according to this embodiment will be described. For example, when washing the biological filtration device 15a with backflow water, the backflow water pump 46 is operated, the valves 28a and 36 of the pipes 22b ₁ and 22c are closed, and the valve 50a ₁ of the backflow water inflow pipe 48 is opened (the valve 50a ₂ is The solid-liquid separation treated water to which the chlorine agent has been added is supplied from the backflow water inflow pipe 48 to the biological filtration device 15a. At this time, when the chlorine agent is added by the chlorine agent adding device 18 so that the residual chlorine concentration in the solid-liquid separation treated water exceeds 1.0 mg / L, the valve 62b of the treated water addition line 60b is opened. Thus, the biologically treated water discharged from the biological filtration device 15b that does not perform the washing with the backflow water is supplied to the backflow water inflow pipe 48, and the residual free chlorine concentration in the solid-liquid separation treated water passing through the backflow water inflow pipe 48 is 0.1 mg / L. Dilute to the range of ~ 1.0 mg / L. The diluted solid-liquid separation treated water (backflow water) is supplied from the backflow water inflow pipe 48 to the biological filtration device 15a. The backflow water supplied to the biological filtration device 15a passes through the filter layer 14b in the direction opposite to the flow of the water to be treated, and the biological carrier is washed.

  If the residual chlorine concentration in the solid-liquid separation treated water in the storage tank 45 is constant, the residual free chlorine concentration in the solid-liquid separation treated water passing through the backflow water inflow pipe 48 is in the range of 0.1 mg / L to 1.0 mg / L. In order to dilute it, a certain amount of biologically treated water may be supplied. However, when the residual chlorine concentration in the solid-liquid separation treated water in the storage tank 45 fluctuates, the valve of the treatment addition line is based on the residual free chlorine concentration value of the residual free chlorine concentration meter installed in the storage tank 45. It is preferable to adjust the amount of biologically treated water added by controlling the degree of release of the water.

  Further, in this embodiment, for example, the residual free chlorine concentration in the finally obtained treated water is set to a relatively high concentration of 0.8 mg / L to 1.0 mg / L or less, but the backflow water cleaning is performed. As a method, the method of adding biologically treated water is applied even when it is preferable to set the concentration lower than the above concentration in terms of the capacity of the biological carrier, etc. (that is, 0.1 mg / L to 0.8 mg / L or less). It is preferable.

  Hereinafter, although an example and a comparative example are given and the present invention is explained more concretely in detail, the present invention is not limited to the following examples.

  In Example 1, the same water treatment apparatus as that shown in FIG. 1 was used, and backflow water cleaning was performed under the following conditions. Table 1 summarizes the water quality results of the treated water thereafter.

<Water treatment device>
Body size of biological filtration device: Φ250mm × H4000mm
Biological carrier: A cylindrical polypropylene filter medium having a diameter of Φ4.0 mm × L4.0 mm and a specific gravity of 1.25 was adopted and filled with a layer height of 1500 mm.
Body size of solid-liquid separation processing equipment: Φ350mm × H3500mm
Filter medium: Silica sand having an effective diameter of 0.6 mm was adopted and filled with a layer height of 600 mm.
<Treatment water>
Water to be treated: Deep well water containing iron 3.0 mg / L, manganese 0.45 mg / L, ammonia nitrogen 0.5 mg / L Water temperature: about 20 ° C.
Fountain type aeration was performed in the landing well so that the concentration of water to be treated in water was 8.0 mg / L.

<Backflow water washing conditions for biological filtration equipment>
After allowing water to be treated to flow at a filtration rate of 240 m / d and 100 times the volume of the biological carrier (100 times the volume of water passed), backflow water is supplied at 5 times the volume of the biological carrier ( The backwashing of the biological carrier was performed with a backwashing water volume of 5). At this time, the biological carrier contact time of the backflow water (that is, the backflow water washing time) was 11.2 minutes. In addition, air backwashing with a blower was performed at a speed of 40 m / h for 4 minutes. The chlorine agent was added so that the residual free chlorine concentration in the backflow water was 1.0 mg / L.

<Backflow water washing conditions for solid-liquid separator>
Biologically treated water was passed at a filtration speed of 120 m / d, and after the air backwashing was performed every 48 hours, the backflow water washing of the filter medium was carried out at a backwater washing speed of 36 m / h for 6 minutes.

  In Example 2, backflow water cleaning was performed using a water treatment apparatus similar to that shown in FIG. In Example 2, a chlorine neutralizer was added to neutralize the chlorine so that the residual free chlorine concentration in the backflow water was 1.0 mg / L. Otherwise, the test was performed under the same conditions as in Example 1. Table 1 summarizes the water quality results of the treated water after the backwashing.

  In Example 3, backflow water cleaning was performed using a water treatment apparatus similar to that shown in FIG. In Example 3, the biologically treated water discharged from the biological filtration device was added to dilute the residual free chlorine concentration in the backflow water to 1.0 mg / L. Otherwise, the test was performed under the same conditions as in Example 1. Table 1 summarizes the water quality results of the treated water after the backwashing.

  FIG. 4 is a schematic diagram showing the configuration of the water treatment device used in Comparative Example 1. First, the water treatment device 4 of Comparative Example 1 will be described. In the water treatment device 4 shown in FIG. 4, a treated water tank 64 and a mixing tank 66 are installed between the biological filtration device 14 and the solid-liquid separation device 16. The biological filtration device 14 and the treated water tank 64 are connected by a pipe 68, and biological treated water discharged from the biological filtration device 14 is supplied to the treated water tank 64. In addition, a partition wall 70 is provided between the treated water tank 64 and the mixing tank 66, and biological treated water in the treated water tank 64 is supplied to the mixing tank 66 beyond the partition wall 70. Yes. Further, the flocculant is supplied into the mixing tank 66, and the biologically treated water and the flocculant are mixed by the stirrer 72. The mixing tank 66 and the solid-liquid separator 16 are connected by a pipe 74, and the mixed liquid is supplied to the solid-liquid separator 16. Moreover, the pump 76 was installed between the treated water tank 64 and the biological filtration apparatus 14 so that the biologically treated water in the treated water tank 64 can be supplied to the biological filtration apparatus 14 and the backflow water washing can be performed. A backflow water inflow pipe 78 is connected. In addition, a pump is provided between the storage tank 45 and the solid-liquid separation device 16 so that the solid-liquid separation treated water in the storage tank 45 can be supplied to the solid-liquid separation device 16 and backflow water cleaning can be performed. A backflow water inflow pipe 82 provided with 80 is connected.

  In Comparative Example 1, reverse water cleaning was performed using the water treatment device 4 shown in FIG. In Comparative Example 1, since the biologically treated water in the treated water tank 64 is used as the backflow water, the residual free chlorine concentration is 0 mg / L. The condition of washing back water in the biological filtration device 14 is that water to be treated is made to flow 400 times the biological carrier volume (400 times the water passing volume) and then 3 times the biological carrier volume. Backflow water (biologically treated water) was supplied (backwashing water volume 3 times), and the biological carrier was backwashed with water. At this time, the biological carrier contact time of the backflow water (that is, the backflow water washing time) was 6.7 minutes. Otherwise, the test was performed under the same conditions as in Example 1. Table 1 summarizes the water quality results of the treated water after backflow water cleaning.

  As can be seen from the results in Table 1, in Examples 1 to 3 in which the residual free chlorine concentration in the backflow water was adjusted to 1.0 mg / L, the removal rate of iron, manganese, and ammonia nitrogen was compared with Comparative Example 1 (conventional method). The removal rate was high as in (1). That is, even when washing with backflow water having a residual free chlorine concentration of 1.0 mg / L, the growth of nitrifying bacteria, manganese-oxidizing bacteria, and iron bacteria is not suppressed as in the conventional method, and biological activity does not decrease. It can be said that. Therefore, the treatment water tank like the conventional method is not required, and the water treatment apparatus can be made slim.

  In Example 4, as the backflow water washing condition of the biological filtration apparatus, after passing water to be treated at a volume 100 times the volume of the biological carrier (water volume multiplied by 100), the volume of the biological carrier is Backflow water (individual liquid separation treated water) was supplied in a 6-fold amount (6-fold backwash water amount), and the biological carrier was backwashed with water. At this time, the biological carrier contact time of the backflow water (that is, the backflow water washing time) was 13.5 minutes. Otherwise, the test was performed under the same conditions as in Example 1. Table 2 summarizes the water quality results of the treated water after backwashing.

  In Example 5, as the backflow water washing condition of the biological filtration apparatus, after passing the water to be treated by 90 times the amount of the biological carrier volume (water passing amount: 90 times), the biological carrier volume Back flow water (individual liquid separation treated water) was supplied in 5 times amount (5 times back wash water amount), and the biological carrier was back water washed. The biological carrier contact time of the backflow water at this time was 11.2 minutes. Otherwise, the test was performed under the same conditions as in Example 1. Table 2 summarizes the water quality results of the treated water after backwashing.

  In Comparative Example 2, as the condition for washing back flow water of the biological filtration device, the treated water was passed through the biological carrier volume at 100 times the amount (100 times the water passage amount), and then the biological carrier volume. Backflow water (solid-liquid separation treated water) was supplied in 5 times amount (5 times backwash water volume), and the biological carrier was backwashed with water. The biological carrier contact time of the backflow water at this time was 13.5 minutes. Otherwise, the test was performed under the same conditions as in Example 1. Table 2 summarizes the water quality results of the treated water after backwashing.

  In Comparative Example 3, as the backflow water washing condition of the biological filtration apparatus, after passing the water to be treated in a 90-fold amount with respect to the biological carrier volume (water-folding volume 90 times), the biological carrier volume Backflow water (solid-liquid separation treated water) was supplied in a 6-fold amount (6 times the backwash water amount), and the biological carrier was backwashed with water. The biological carrier contact time of the backflow water at this time was 13.5 minutes. Otherwise, the test was performed under the same conditions as in Example 1. Table 2 summarizes the water quality results of the treated water after backwashing.

  In Comparative Example 4, as a condition for washing back flow water of the biological filtration device, water to be treated is passed by 400 times the biological carrier volume (400 times the water passing volume), and then the biological carrier volume. Backflow water (solid-liquid separation treated water) was supplied in 3 times the amount (3 times backwash water amount), and the biological carrier was backwashed with water. The biological carrier contact time of the backflow water at this time was 6.7 minutes. Otherwise, the test was performed under the same conditions as in Example 1. Table 2 summarizes the water quality results of the treated water after backwashing.

  As can be seen from the results in Table 2, when the residual free chlorine concentration in the backflow water exceeds 1.0 mg / L (Comparative Example 2), the double water flow rate and the backwash water double amount are the same as in Example 1. It was found that the removal rate of iron decreased. That is, the growth of iron bacteria was suppressed and the biological activity was reduced. Moreover, in Comparative Example 4 in which the residual free chlorine concentration in the backflow water was higher than that in Comparative Example 2, the growth of microorganisms was further suppressed and the biological activity was reduced. Moreover, when the amount of water flow was less than 100 times and the amount of backwash water was more than 5 times (Comparative Example 3), the growth of microorganisms was further suppressed and the biological activity was reduced. On the other hand, as in Examples 4 and 5, when the residual free chlorine concentration in the backflow water is 1.0 mg / L, even if the water flow rate is less than 100 times or the backwash water rate is more than 5 times, Although the growth of iron bacteria was slightly suppressed, the removal rate close to that of Example 1 was shown.

It is a schematic diagram which shows an example of a structure of the water treatment apparatus which concerns on this embodiment. It is a schematic diagram which shows an example of a structure of the water treatment apparatus which concerns on other embodiment of this invention. It is a schematic diagram which shows an example of a structure of the water treatment apparatus which concerns on other embodiment of this invention. It is a schematic diagram which shows the structure of the water treatment apparatus used in the comparative example 1.

Explanation of symbols

1, 2, 3, 4 Water treatment device, 10 well pump, 12 landing well, 14, 15a, 15b biological filtration device, 14a, 16a main body, 14b, 16b filtration layer, 14c network, 16 solid-liquid separation device, 18 chlorine addition device, 20 backflow water cleaning _{device, 22a, 22b, 22c, 22b} 1, 22b 2 pipe, 24 a blower, 26 an air _{pipe, 28,28a, 28b, 36,50a, 50b} , 50a 1, 50a 2, 62a , 62b Valve, 30 Coagulant tank, 32 Coagulant addition pump, 34 Coagulant inflow pipe, 38 Chlorine agent tank, 40 Chlorine addition pump, 42 Residual free chlorine concentration meter, 44 Chlorine inflow pipe, 45 Storage tank, 46 Backflow water pump, 48, 78, 82 Backflow water inflow pipe, 52 Chlorine neutralizer supply device, 54 Chlorine neutralizer tank, 56 Chlorine neutralizer pump, 58 Chlorine neutralizer inflow pipe, 60a, 60b treated water addition line, 64 treated water tank, 66 mixing tank, 68, 74 piping, 70 partition, 72 agitator, 76, 80 pump.

Claims (9)

A biological filtration device comprising a biological carrier for removing or oxidizing ammonia, iron and manganese in the water to be treated, and a solid-liquid separation device comprising a filter medium for solid-liquid separation of biological treatment water discharged from the biological filtration device A chlorinating agent adding means for adding a chlorinating agent to at least one of the biologically treated water discharged from the biological filtration device, the solid-liquid separating treated water discharged from the solid-liquid separation device, and the chlorinating agent-containing A solid water-separated treated water is supplied to the biological filtration device, and includes a reverse water cleaning means for performing reverse water cleaning of the biological carrier,
The chlorinating agent adding means adds the chlorinating agent so that the residual free chlorine concentration of the solid-liquid treated water containing the chlorinating agent supplied to the biological filtration device is 0.1 mg / L to 1.0 mg / L. The water treatment apparatus characterized by the above-mentioned. A biological filtration device comprising a biological carrier for removing or oxidizing ammonia, iron and manganese in the water to be treated, and a solid-liquid separation device comprising a filter medium for solid-liquid separation of biological treatment water discharged from the biological filtration device A chlorinating agent adding means for adding a chlorinating agent to at least one of the biologically treated water discharged from the biological filtration device, the solid-liquid separating treated water discharged from the solid-liquid separation device, and the chlorinating agent-containing A solid water-separated treated water is supplied to the biological filtration device, and includes a reverse water cleaning means for performing reverse water cleaning of the biological carrier,
The backflow water washing means includes a chlorine neutralizer addition means for adding a chlorine neutralizer to the chlorine-containing solid-liquid separation treated water, and the chlorine-agent-containing solid-liquid separation treated water supplied to the biological filtration device A water treatment apparatus, wherein a chlorine neutralizing agent is added so that a residual free chlorine concentration of 0.1 to 1.0 mg / L. A biological filtration device comprising a biological carrier for removing or oxidizing ammonia, iron and manganese in the water to be treated, and a solid-liquid separation device comprising a filter medium for solid-liquid separation of biological treatment water discharged from the biological filtration device A chlorinating agent adding means for adding a chlorinating agent to at least one of the biologically treated water discharged from the biological filtration device, the solid-liquid separating treated water discharged from the solid-liquid separation device, and the chlorinating agent-containing A solid water-separated treated water is supplied to the biological filtration device, and includes a reverse water cleaning means for performing reverse water cleaning of the biological carrier,
A plurality of the biological filtration devices are provided,
The backflow water washing means adds a part of the biologically treated water discharged from the biological filtration device that does not perform the backflow water cleaning to the solid-liquid separation treatment water containing the chlorine agent supplied to the biological filtration device that performs the backflow water washing. The residual free chlorine concentration of the chlorinating agent-containing solid-liquid separation treated water supplied to the biological filtration apparatus that performs the backflow water washing is 0.1 mg / L to 1.0 mg / L. A biological treatment water is added to the water treatment apparatus.   It is a water treatment apparatus of any one of Claims 1-3, Comprising: The said backflow water washing | cleaning means is after supplying the said to-be-processed water to the said biofiltration apparatus by 100 times or more amount of the said biocarrier capacity | capacitance. The water treatment device is characterized in that the chlorinating agent-containing solid-liquid separation treated water is supplied to the biological filtration device in a range of 2 to 5 times the biological carrier capacity, and the biological carrier is washed back-flowing water. .   5. The water treatment device according to claim 1, wherein the backflow water cleaning means supplies the solid-liquid separation treatment water containing the chlorine agent to the solid-liquid separation treatment device, and A water treatment apparatus that performs reverse flow cleaning of a filter medium. It is obtained from a biological filtration step for removing or oxidizing ammonia, iron and manganese in water to be treated by a biological carrier, a solid-liquid separation step for solid-liquid separation of biologically treated water obtained from the biological filtration step, and the biological filtration step. The biological carrier is treated with a chlorine agent addition step of adding a chlorine agent to at least one of the biologically treated water and the solid-liquid separation treated water obtained from the solid-liquid separation step, and the solid-liquid separation treated water containing the chlorine agent. A reverse water cleaning process for performing reverse water cleaning of
In the chlorinating agent adding step, the chlorinating agent is added so that the residual free chlorine concentration of the solid-liquid separation treated water containing the chlorinating agent is 0.1 mg / L to 1.0 mg / L. Processing method. It is obtained from a biological filtration step for removing or oxidizing ammonia, iron and manganese in water to be treated by a biological carrier, a solid-liquid separation step for solid-liquid separation of biologically treated water obtained from the biological filtration step, and the biological filtration step. The biological carrier is treated with a chlorine agent addition step of adding a chlorine agent to at least one of the biologically treated water and the solid-liquid separation treated water obtained from the solid-liquid separation step, and the solid-liquid separation treated water containing the chlorine agent. A reverse water cleaning process for performing reverse water cleaning of
In the backflow water washing step, a chlorine neutralizer is added to the chlorine-containing solid-liquid separation treated water, and the residual free chlorine concentration of the chlorine-containing solid-liquid separation treated water is 0.1 mg / L to 1.. A water treatment method characterized by setting to 0 mg / L. It is obtained from a biological filtration step for removing or oxidizing ammonia, iron and manganese in water to be treated by a biological carrier, a solid-liquid separation step for solid-liquid separation of biologically treated water obtained from the biological filtration step, and the biological filtration step. The biological carrier is treated with a chlorine agent addition step of adding a chlorine agent to at least one of the biologically treated water and the solid-liquid separation treated water obtained from the solid-liquid separation step, and the solid-liquid separation treated water containing the chlorine agent. A reverse water cleaning process for performing reverse water cleaning of
A plurality of biological filtration devices comprising the biological carrier are provided ,
In the backflow water washing step, the chlorinated agent-containing solid-liquid separation treated water supplied to the biological filtration device provided with the biological carrier that performs backflow water cleaning is discharged from the biological filtration device that includes the biological carrier that does not perform backflow water washing. A water treatment method characterized by adding a part of biologically treated water and setting the residual free chlorine concentration of the chlorinated agent-containing solid-liquid separated treated water to 0.1 mg / L to 1.0 mg / L.   It is the water treatment method of any one of Claims 6-8, Comprising: In the said backflow water washing | cleaning process, after supplying the said to-be-processed water to the said biological carrier by the 100 times amount or more of the said biological carrier capacity | capacitance, A water treatment method, wherein the chlorinating solid-liquid separation treated water is supplied to the biological carrier in a range of 2 to 5 times the biological carrier volume, and the biological carrier is backwashed.

Images