Water treatment system and water treatment method

Abstract

To reduce a burden associated with a nitrification treatment of treatment target water and a burden associated with a reuse of the treatment target water.SOLUTION: There is provided a water treatment system 1 including: an ammonia treatment system 100 including a control unit for adjusting an ammonia concentration of treatment target water 2, and a release unit 40 for releasing a portion of the treatment target water 2 whose ammonia concentration has been adjusted; an ammonia adding unit 202 into which water to be reused 3 that has not been released by the release unit 40 flows, and which is configured to add an ammonia compound to inflowing reuse target water 4; a reactant introduction unit 203 that adds a reactant that reacts with the ammonia compound and ammonia remaining in the reuse target water 4 to generate a sterilizing substance to the inflowing reuse target water 4; and a reuse system that reuses the reuse target water 4 and includes a filter unit 204 suppressing biofouling by a bactericidal substance contained in the reuse target water.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a water treatment system and a water treatment method.

Background Art

[0002] For improving regional public health, treatment of contaminated water such as sewage is very important. As a typical method for treating contaminated water, there is nitrification treatment for nitrifying ammonia nitrogen by using a biological treatment process such as the activated sludge method.

[0003] On the other hand, there is a technology (reuse technology) that uses seawater, sewage, industrial wastewater, etc. as raw water, treats the raw water to remove salts and trace contaminants, and generates reclaimed water that can be reused for drinking, etc. For example, with membrane treatment, microorganisms grow, causing problems such as clogging of the raw water flow path, and thus measures against biofouling that significantly reduce the device performance are required.

[0004] As a technology related to membrane cleaning, for example, in Patent Document 1, when diluting a high-concentration sodium hypochlorite solution stored in a chemical solution tank with membrane-treated water to chemically clean the separation membrane, the ammonia nitrogen concentration in the membrane-treated water is monitored by a monitoring device, and based on this concentration, a control device controls a chemical solution injection pump and adjusts the dilution ratio, so that even when there is a change in the water quality of the membrane-treated water, the concentration of sodium hypochlorite in the backwash water is kept constant to prevent fluctuations in the chemical cleaning effect.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] By the way, in such water treatment, the cost often becomes high. For example, in nitrification treatment, it is necessary to perform aeration treatment to maintain the metabolic activity of microorganisms and adjust the ammonia concentration, and the power cost for this is extremely large. On the other hand, in membrane treatment for reuse, although DBNPA (2,2-dibromo-3-nitrilopropionamide) and the like are used as biofouling inhibitors that do not cause membrane deterioration, there are problems such as being expensive and having restricted use for drinking water applications. For example, as described in Patent Document 1, biofouling inhibition by bound chlorine such as chloramine is known and used.

[0007] The present invention has been made in view of such problems, and an object thereof is to provide a water treatment system and a water treatment method capable of reducing both the burden related to nitrification treatment of water to be treated and the burden related to reuse of the target treated water.

Means for Solving the Problems

[0008] One aspect of the present invention for solving the above problems includes an ammonia treatment system including a control unit that adjusts the ammonia concentration of water to be treated and a discharge unit that discharges a part of the water to be treated whose ammonia concentration has been adjusted, and reuse target water that is the water to be treated that has not been discharged by the discharge unit among the water to be treated whose ammonia concentration has been adjusted flows in, an ammonia addition unit that adds a predetermined ammonia compound to the flowing-in reuse target water, a reactant introduction unit that adds a reactant that generates a predetermined bactericidal substance by reacting with the ammonia compound and the ammonia remaining in the reuse target water to the flowing-in reuse target water, and a reuse system including a filter unit that reuses the reuse target water and suppresses biofouling by the bactericidal substance contained in the reuse target water.

Effects of the Invention

[0009] According to the present invention, it is possible to reduce both the burden related to nitrification treatment of water to be treated and the burden related to reuse of the target treated water. Configurations, effects, etc. other than those described above will be clarified by the following description of the embodiments.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0011] An embodiment of the present invention will be described with reference to the drawings.

[0012] FIG. 1 is a diagram showing an example of the configuration of the water treatment system 1 according to the present embodiment. The water treatment system 1 includes an ammonia treatment system 100 including one or more aerobic tanks 10, a PLC 20 (Programmable Logic Controller), a blower unit 30, and a discharge unit 40, a reuse system 200, and an information processing device 300.

[0013] Between the PLC 20 and the information processing device 300, and between the PLC 20 and the blower unit 30, they are communicably connected by wired or wireless communication networks 50, 51 such as, for example, the Internet, a LAN (Local Area Network), a WAN (Wide Area Network), a VPN (Virtual Private Network), or a dedicated line.

[0014] The ammonia treatment system 100 is a nitrification treatment system that nitrifies water (treatment target water 2) such as sewage containing contaminants such as organic substances or ammonia nitrogen introduced into each aerobic tank 10 (10A - 10C) at a predetermined flow rate to reduce the ammonia concentration (ammonia nitrogen concentration; the same applies hereinafter) to a target concentration (for example, 2 to 3 mg / L). The treatment target water 2 (ammonia residual water) with a reduced ammonia concentration is introduced into the reuse system 200.

[0015] Each aerobic tank 10 is provided with a DO meter 11 and a pH meter 12. The DO meter 11 and the pH meter 12 measure the dissolved oxygen (DO) concentration and the pH of the water 2 to be treated in the aerobic tank 10, respectively. Further, an ammonia meter 13 is provided in one of the aerobic tanks 10, namely the aerobic tank 10A. The ammonia meter 13 is a measuring unit that measures the ammonia concentration of the water 2 to be treated in the aerobic tank 10A. In addition, each aerobic tank 10 is provided with a concentration meter (not shown) that measures the concentrations of various substances such as biochemical oxygen demand (BOD), chemical oxygen demand (COD), total nitrogen, ammonia nitrogen, and total phosphorus.

[0016] The air supply unit 30 is configured to include, for example, a blower, and performs aeration by sending air 31 containing oxygen into each aerobic tank 10. This promotes nitrification by the microorganisms contained in the water 2 to be treated.

[0017] The air volume supplied by the air supply unit 30 is controlled by a control signal 52 from the PLC 20, which is a control unit. Based on the introduction amount (inflow amount) of the water 2 to be treated into each aerobic tank 10, the outflow amount of the water 2 to be treated from each aerobic tank 10, and the water quality (ammonia concentration, dissolved oxygen concentration, pH, etc.) of each aerobic tank 10, the PLC 20 performs air supply control so that the ammonia concentration of the water 2 to be treated in each aerobic tank 10 reaches a preset target concentration, thereby adjusting the ammonia concentration of each aerobic tank 10. The inflow amount and the outflow amount of the water 2 to be treated are measured by a flow meter (not shown) or the like.

[0018] At this time, the PLC 20 estimates the current ammonia concentration in the aerobic tanks 10B and 10C based on a predetermined relational expression between the measured value of the ammonia meter 13 in the aerobic tank 10A and the measured values of the DO meter 11 and the pH meter 12, thereby adjusting the ammonia concentration of each aerobic tank 10.

[0019] In the ammonia treatment system 100, an ammonia meter may be provided for each aerobic tank 10. Thereby, the ammonia concentration of each aerobic tank 10 can be specified without using the above relational expression.

[0020] Also, the adjustment of the ammonia concentration in the ammonia treatment system 100 may be performed by the air volume control as described herein, or the ammonia concentration may be adjusted by controlling other physical or chemical characteristics such as the dissolved oxygen concentration. For example, control may be performed to change the dissolved oxygen concentration while controlling the air volume to be constant.

[0021] Such control (air volume control such as aeration) in the ammonia treatment system 100 generally requires a high cost (cost or energy), but as will be described later, the water treatment system 1 of the present embodiment is a treatment system capable of reducing such a burden.

[0022] Next, the treated water 2 with the ammonia concentration adjusted by each aerobic tank 10 flows through the pipeline 32, and a predetermined ratio (hereinafter referred to as the regeneration ratio) is introduced into the reuse system 200. On the other hand, the remaining treated water 2 is introduced into the discharge section 40.

[0023] The discharge section 40 is a pipeline through which the remainder of the ammonia residual water (the discharged water 3) flows. A sterilizing substance introduction section 41 is provided at a predetermined position of the discharge section 40. The sterilizing substance introduction section 41 sterilizes the discharged water 3 flowing through the discharge section 40 by introducing a predetermined substance (sodium hypochlorite) into the discharge section 40. A control device (not shown) is provided in the sterilizing substance introduction section 41, and the introduction amount of the above substance can be adjusted.

[0024] A predetermined upper limit value (hereinafter referred to as the discharged water regulation value) is set for the ammonia concentration in the discharged water 3 discharged from the discharge section 40. It is required that the ammonia concentration in the discharged water 3 be below this discharged water regulation value.

[0025] Note that the discharge section 40 may be provided for each series of the aerobic tanks 10, or may be provided for a pipeline that aggregates the treated water 2 from each aerobic tank 10.

[0026] The above ammonia treatment system 100 is realized by, for example, at least one of the methods such as the standard activated sludge method, the carrier activated sludge method, the membrane separation activated sludge method, or the batch activated sludge method.

[0027] Next, the reuse system 200 is a treatment system that reuses the target treated water (reuse target water 4) from the ammonia treatment system 100 to obtain reclaimed water (produced water 5). The produced water 5 is sent to predetermined facilities and used for purposes such as drinking.

[0028] The reuse system 200 includes a main flow path 201, an ammonia addition section 202, a reactant introduction section 203, a reuse device 205 including a filter section 204, and a branch section 206.

[0029] The main flow path 201 is a pipeline through which the reuse target water 4 flows.

[0030] An ammonia addition section 202 is provided at a predetermined position of the main flow path 201. The ammonia addition section 202 raises the ammonia concentration in the reuse target water 4 flowing through the main flow path 201 by introducing a predetermined ammonia compound into the main flow path 201. A control device (not shown) is provided in the ammonia addition section 202, and the introduction amount of the ammonia compound can be adjusted. The generation of the bactericidal substance described below is promoted by the increase in the ammonia concentration.

[0031] However, usually, the procurement of ammonia compounds requires a much larger burden (cost, work, etc.) compared to sodium hypochlorite, a bactericide.

[0032] The ammonia compound is, for example, an ammonium salt having ammonia nitrogen, such as ammonium sulfate or ammonium chloride. In this embodiment, it is assumed that the ammonia compound is ammonium sulfate.

[0033] Also, a reactant introduction section 203 is provided at a predetermined position of the main flow path 201 on the downstream side of the ammonia addition section 202. By introducing a predetermined reactant into the main flow path 201, the reactant introduction section 203 causes a reaction with ammonia in the water 4 to be reused flowing through the main flow path 201 to generate a predetermined disinfectant. A control device (not shown) is provided in the reactant introduction section 203, and the introduction amount of the above reactant can be adjusted.

[0034] The above reactant is, for example, a chlorine compound (free chlorine-containing solution) such as sodium hypochlorite, and the free chlorine of the chlorine compound reacts with the ammonia compound or the ammonia nitrogen in the water 4 to be reused to generate a disinfectant. In this embodiment, this reactant is assumed to be sodium hypochlorite.

[0035] Also, the above disinfectant is, for example, a disinfectant or an oxidant mainly composed of combined halogen such as chloramine (chloroamine). This disinfectant is a compound generated by reacting with the ammonia compound or the ammonia nitrogen in the water 4 to be reused, and is a nitrogen compound in which a part of the hydrogen atoms on the ammonia compound is replaced by chlorine atoms. In this embodiment, this disinfectant is assumed to be chloramine.

[0036] Note that the order of the ammonia addition section 202 and the reactant introduction section 203 may be reversed.

[0037] Furthermore, a reuse device 205 is provided at a predetermined position of the main flow path 201 on the downstream side of the reactant introduction section 203. The reuse device 205 includes a filter section 204. The filter section 204 is composed of, for example, a microfiltration membrane (MF membrane), an ultrafiltration membrane (UF membrane), and a reverse osmosis membrane (RO membrane). The reverse osmosis membrane is composed of, for example, polyamide or the like. The reverse osmosis membrane suppresses biofouling by removing salts and trace contaminants contained in the water 4 to be reused.

[0038] Then, the reuse device 205 sends a part of the water 4 to be reused from which contaminants and the like have been removed to a predetermined facility as the produced water 5. On the other hand, the other part (brine) of the water 4 to be reused from which contaminants and the like have been removed is sent to the discharge unit 40 through the branch unit 206 connected to the discharge unit 40, and sterilization is performed by the sterilizing substance introduction unit 41.

[0039] Here, in the filter unit 204, clogging may be caused by microorganisms and the like in the water 4 to be reused, and the reuse performance of the reuse device 205 may decrease. However, even in such a case, due to the sterilizing action of the sterilizing substance generated based on the reaction substance introduction unit 203 and the like, the causative substance that causes clogging of the filter unit 204 is decomposed, and clogging of the filter unit 204 is prevented.

[0040] In addition, each reaction in the above ammonia treatment system 100 and reuse system 200 is performed, for example, under normal temperature and pressure.

[0041] Next, the information processing device 300 includes a control device (arithmetic device) such as a CPU (Central Processing Unit), DSP (Digital Signal Processor), GPU (Graphics Processing Unit), FPGA (Field-Programmable Gate Array), ASIC (Application Specific Integrated Circuit), a storage device such as a RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), or SSD (Solid State Drive), a communication device composed of a NIC (Network Interface Card), a wireless communication module, a USB (Universal Serial Interface) module, or a serial communication module, an input device such as a keyboard, a mouse, or a touch panel, and an output device such as a liquid crystal monitor or an LCD (Liquid Crystal Display).

[0042] Then, the information processing apparatus 300 has the following functions (programs).

[0043] First, the information processing apparatus 300 stores the upper limit value (effluent water regulation value) of the ammonia concentration of the water 2 to be treated that can be discharged from the discharge unit 40.

[0044] Also, based on the ammonia concentration of the water 2 to be treated measured by the ammonia meter 13, the information processing apparatus 300 calculates the amount of burden (hereinafter referred to as the first burden amount) generated in the ammonia treatment system 100 under the control of the PLC 20.

[0045] In addition, the information processing apparatus 300 calculates the amount of burden (hereinafter referred to as the second burden amount) generated in the reuse system 200 by adding the ammonia compound (ammonium sulfate) and the reactant (sodium hypochlorite) used for generating the bactericidal substance (chloramine).

[0046] Then, based on the first burden amount and the second burden amount, the information processing apparatus 300 calculates the target concentration of ammonia and controls the PLC 20 so that the ammonia concentration of the water 2 to be treated in the ammonia treatment system 100 becomes the calculated target concentration.

[0047] Specifically, based on the first burden amount and the second burden amount, the information processing apparatus 300 determines whether the reduction of the burden on the ammonia treatment system 100 should be prioritized over the reduction of the burden on the reuse system 200. When it is determined that the reduction of the burden on the ammonia treatment system 100 should be prioritized over the reduction of the burden on the reuse system 200, the upper limit value (effluent water regulation value) of the ammonia concentration is set to the target concentration, and the PLC 20 is controlled so that the ammonia concentration of the water 2 to be treated in the ammonia treatment system 100 becomes the set target concentration.

[0048] On the other hand, when the information processing device 300 determines that the reduction of the burden on the ammonia treatment system 100 should not be prioritized over the reduction of the burden on the reuse system 200, it determines whether the upper limit value (effluent regulation value) exceeds a predetermined threshold. When the upper limit value exceeds the predetermined threshold, it calculates the ammonia concentration of the water to be treated 2 that should be achieved in the ammonia treatment system 100, which is necessary to generate a bactericidal substance (chloramine), sets the calculated ammonia concentration as the target concentration, and controls the PLC 20 so that the ammonia concentration of the water to be treated 2 in the ammonia treatment system 100 becomes the set target concentration. On the other hand, when the upper limit value does not exceed the predetermined threshold, the information processing device 300 sets the upper limit value as the target concentration and controls the PLC 20 so that the ammonia concentration of the water to be treated 2 in the ammonia treatment system 100 becomes the set target concentration.

[0049] Each function of the information processing device 300 described above is realized by the control device reading and executing each program stored in the storage device. Also, each program can be recorded and distributed on a recording medium, for example. Note that all or part of the information processing device 300 may be realized using virtual information processing resources provided using virtualization technology, process space separation technology, etc., such as a virtual server provided by a cloud system. Also, all or part of the functions provided by the information processing device 300 may be realized by a service provided by a cloud system via an API (Application Programming Interface) or the like.

[0050] Note that the information processing device may control each device in the ammonia treatment system 100 and the reuse system 200. Next, the control performed in the water treatment system 1 will be described.

[0051] FIG. 2 is a flowchart for explaining an example of the control process (water treatment system control process) of the water treatment system 1 according to the present embodiment. The water treatment system control process is repeatedly executed, for example, at a predetermined timing (for example, a predetermined time or a predetermined time interval), or when a predetermined input is made to the information processing device 300.

[0052] First, the information processing device 300 calculates the load amount (first load amount) generated in the ammonia treatment system 100 by the air volume control by the PLC 20 (s11).

[0053] For example, first, the information processing device 300 acquires information on the target concentration of ammonia in the reuse target water 4 discharged from the aerobic tank 10. Further, the information processing device 300 acquires the current ammonia concentration in the reuse target water 4 from the ammonia meter 13. Further, the information processing device 300 acquires the inflow amount of the water to be treated 2 into the aerobic tank 10 and the outflow amount of the water to be treated 2 from the aerobic tank 10 by a flow meter. Further, the information processing device 300 acquires the concentrations of various substances in the water to be treated 2 in the aerobic tank 10 by each concentration meter. The inflow amount and the outflow amount may be acquired from the actual values in the past operation of the water treatment system.

[0054] Then, based on the acquired information, the information processing device 300 calculates the required amount of oxygen for maintaining the ammonia concentration in each aerobic tank 10 at the target concentration, and calculates the air volume of the blower unit 30 according to the calculated required amount of oxygen, thereby calculating the amount of electric power and the electricity charge required for the operation of the blower unit 30. When calculating the required amount of oxygen, the required amounts of oxygen related to BOD oxidation, nitrification, endogenous respiration, and DO maintenance are calculated as the required amounts of oxygen for biological treatment. The derivation method for each item is disclosed, for example, in "Sewerage Facility Planning and Design Guidelines and Explanation" (Japan Sewerage Association, 2019), etc.

[0055] Note that the information processing device 300 may consider other costs in the ammonia treatment system 100 (for example, the operating cost of the pump for adjusting the flow rate of the water to be treated 2 or the operating cost of the blower unit 30) in the load amount.

[0056] Next, the information processing apparatus 300 acquires information on the reproduction ratio (S12). For example, the information processing apparatus 300 may read the information on the reproduction ratio stored in advance, may receive an input of the reproduction ratio from the administrator, or may acquire the information on the reproduction ratio from the reuse system 200. Further, the information processing apparatus 300 may calculate the reproduction ratio based on the outflow amount of the water to be treated 2 from the ammonia treatment system 100, the amount of the water to be reused 4 flowing into the reuse apparatus 205, or the amount of the discharged water 3 flowing into the discharge unit 40.

[0057] Furthermore, the information processing apparatus 300 specifies the concentration of chloramine necessary for suppressing biofouling in the filter unit 204, and calculates the amount of burden (second amount of burden) generated in the reuse system 200 due to the introduction of ammonium sulfate by the ammonia addition unit 202 and / or the introduction of sodium hypochlorite by the reactant introduction unit 203, which is necessary for generating chloramine at that concentration (S13).

[0058] For example, first, the information processing apparatus 300 sets an arbitrary value less than 4 mg / L, which is the concentration that does not deteriorate the filter unit 204, as the concentration of chloramine necessary for suppressing biofouling.

[0059] Then, the information processing apparatus 300 calculates the amount (or concentration) of sodium hypochlorite (from the reactant introduction unit 203) and the total amount (or concentration) of ammonia (the total amount of ammonia in the water to be reused 4 introduced into the reuse system 200 and the amount of ammonium sulfate introduced from the ammonia addition unit 202) necessary for generating chloramine at this concentration based on the stoichiometric ratio indicated by the chemical reaction formula related to chloramine generation. Then, the information processing apparatus 300 subtracts the amount of ammonia in the water to be reused 4 calculated from the reproduction ratio calculated in S12 from the total amount of ammonia calculated, thereby calculating the introduction amount of ammonium sulfate from the ammonia addition unit 202 and the cost of the introduced ammonium sulfate.

[0060] Note that the information processing device 300 may consider other costs in the reuse system 200 (for example, the operating cost of the pump for adjusting the flow rate of the water 4 to be reused, the operating cost of the ammonia addition unit 202, or the operating cost of the reactant introduction unit 203) in the burden amount.

[0061] Based on the first burden amount calculated in s11 and the second burden amount calculated in s13, the information processing device 300 creates a determination formula for determining whether to prioritize reducing the burden on the ammonia treatment system 100 over reducing the burden on the reuse system 200 (s14).

[0062] For example, the information processing device 300 calculates the value of {(the second burden amount calculated in s13)} / ((the second burden amount calculated in s13)+(the first burden amount calculated in s11)}. Also, the information processing device 300 sets the regeneration ratio calculated in s12 as a threshold value.

[0063] Based on the determination formula created in s14, the information processing device 300 determines whether to prioritize reducing the burden on the ammonia treatment system 100 over reducing the burden on the reuse system 200 (s15). For example, the information processing device 300 determines whether the value calculated in s14 is smaller than the threshold value set in s14.

[0064] When it is necessary to prioritize reducing the burden on the ammonia treatment system 100 over reducing the burden on the reuse system 200 (s15: YES), the information processing device 300 executes the process of s16. When it is not necessary to prioritize reducing the burden on the ammonia treatment system 100 over reducing the burden on the reuse system 200 (s15: NO), the information processing device 300 executes the process of s18.

[0065] In s16, the information processing device 300 calculates the target concentration of each aerobic tank 10 of the ammonia treatment system 100 such that the ammonia concentration of the treated water 3 becomes the treated water regulation value. The treated water regulation value is, for example, 1 mg / L or 4 mg / L.

[0066] For example, based on the effluent water regulation value, the regeneration ratio, the outflow volume of the water to be treated 2 from the ammonia treatment system 100, etc., the information processing device 300 calculates the concentration to be achieved as the ammonia concentration of the water to be treated 2 in each aerobic tank 10 of the ammonia treatment system 100.

[0067] Then, based on the calculated target concentration, the information processing device 300 controls the air blowing by the air blowing unit 30 (s17).

[0068] For example, the information processing device 300 transmits the concentration calculated in s16 to the PLC 20 as the target concentration. The PLC 20 controls the air blowing unit 30 so that the ammonia concentration of the water to be treated 2 in each aerobic tank 10 reaches and maintains the target concentration.

[0069] Note that during the control of s17, when chloramine is not generated in the reuse system 200 at a predetermined concentration (for example, 2 to 3 mg / L) or more, the ammonia addition unit 202 may introduce an ammonium compound into the main flow path 201 so as to generate chloramine at a predetermined concentration or more.

[0070] By controlling the ammonia concentration in s16 and s17, the load amount (especially the electricity cost related to the air volume control) in the ammonia treatment system 100 can be reduced.

[0071] On the other hand, in s18, the information processing device 300 determines whether the effluent water regulation value exceeds a predetermined concentration (for example, 1 mg / L).

[0072] When the effluent water regulation value exceeds the predetermined concentration (s18: YES), the information processing device 300 executes the process of s19. When the effluent water regulation value does not exceed the predetermined concentration (s18: NO), the information processing device 300 executes the process of s21.

[0073] In s19, the information processing device 300 calculates the ammonia concentration of the water to be treated 2 in the ammonia treatment system 100 that is necessary to generate chloramine at a predetermined concentration or higher (for example, 2 to 3 mg / L), and sets the calculated ammonia concentration as the target concentration.

[0074] For example, the information processing device 300 calculates the amount of ammonia necessary to generate chloramine at the concentration to be achieved based on the stoichiometric ratio indicated by the chemical reaction formula related to chloramine generation. Then, the information processing device 300 calculates the ammonia concentration of the water to be treated 2 in each aerobic tank 10 such that the calculated amount of ammonia can flow from the ammonia treatment system 100 into the reuse system 200 based on the regeneration ratio or the like, and sets the calculated concentration as the target concentration.

[0075] Then, the information processing device 300 controls the air blowing by the air blowing unit 30 based on the calculated target concentration (s20).

[0076] For example, the information processing device 300 transmits the target concentration calculated in s19 to the PLC 20. The PLC 20 controls the air blowing unit 30 so that the ammonia concentration of the water to be treated 2 in each aerobic tank 10 reaches the target concentration and maintains it.

[0077] Note that according to this process, the addition of ammonia by the ammonia addition unit 202 is basically unnecessary. However, when chloramine is not generated at a predetermined concentration (for example, 2 to 3 mg / L) or higher in the reuse system 200, the ammonia addition unit 202 may introduce an ammonium compound into the main flow path 201 so as to generate chloramine at a predetermined concentration or higher.

[0078] By controlling the ammonia concentration in s19 and s20, the load amount in the reuse system 200 (particularly, the addition of ammonium sulfate by the ammonia addition unit 202) can be reduced.

[0079] In s21, the information processing apparatus 300 calculates, in the same manner as in s16, the target concentration of each aerobic tank 10 of the ammonia treatment system 100 such that the ammonia concentration of the treated effluent 3 becomes the treated effluent regulation value.

[0080] Then, the information processing apparatus 300 controls the air blowing by the air blowing unit 30 based on the calculated target concentration, in the same manner as in s17 (s22).

[0081] By controlling the ammonia concentration in s21 and s22, the load amount in the reuse system 200 (particularly, the addition of sodium hypochlorite by the reactant introduction unit 203) can be reduced.

[0082] As described above, the water treatment system 1 of the present embodiment includes a reuse system 200 including an ammonia addition unit 202 that adds a predetermined ammonia compound (such as ammonium sulfate) to the reuse target water 4 that has flowed in, a reactant introduction unit 203 that adds a reactant (such as sodium hypochlorite) that reacts with the ammonia compound and the ammonia remaining in the reuse target water 4 to generate a predetermined bactericidal substance (such as chloramine), and a filter unit 204 that reuses the reuse target water 4 and suppresses biofouling by the bactericidal substance contained in the reuse target water 4.

[0083] That is, the water treatment system 1 of the present embodiment generates a bactericidal substance by reacting the reuse target water 4 from the ammonia treatment system 100 with the ammonia compound from the ammonia addition unit 202 and the reactant from the reactant introduction unit 203, whereby biofouling is suppressed in the filter unit 204 that reuses the reuse target water 4.

[0084] As a result, the ammonia remaining in the ammonia treatment system 100 can be used to maintain or improve the performance of the regeneration treatment of the reuse target water 4 in the reuse system 200, and the burden (such as the cost of ammonia compounds) related to reuse in the reuse system 200 can be reduced. In addition, the amount of adjustment (decrease amount) of the ammonia concentration performed in the ammonia treatment system 100 can be reduced by the amount used to maintain or improve the performance of the regeneration treatment, so that the burden (cost, etc.) related to ammonia treatment in the ammonia treatment system 100 can be reduced.

[0085] As described above, according to the water treatment system 1 of the present embodiment, it is possible to reduce both the burden related to the nitrification treatment of the water to be treated 2 and the burden related to the reuse of the target treated water. For example, the OPEX (Operating Expense) in ammonia treatment can be improved.

[0086] Further, the information processing device 300 of the water treatment system 1 of the present embodiment calculates the target concentration of ammonia in the ammonia treatment system 100 based on the burden amount of the ammonia treatment system 100 generated by the adjustment control of the ammonia concentration by the PLC 20 and the burden amount of the reuse system 200 generated by the generation of the bactericidal substance (the burden amount related to the suppression of biofouling), and controls the PLC 20 so that the ammonia concentration of the water to be treated 2 becomes the target concentration.

[0087] As a result, it is possible to control the ammonia concentration and perform the regeneration treatment of the water to be treated 2 with an appropriate balance considering the burden in the ammonia treatment system 100 and the burden in the reuse system 200. And the composite control by sewage treatment and regeneration treatment can be optimized.

[0088] Further, when the reduction of the burden (cost, etc.) of the ammonia treatment system 100 should be given priority over the burden (cost, etc.) of the reuse system 200, the information processing device 300 of the water treatment system 1 of the present embodiment performs control of the ammonia concentration with the upper limit value of the ammonia concentration in the ammonia treatment system 100 as the target.

[0089] This can minimize the control of ammonia concentration and reduce the burden (cost, etc.) on the ammonia treatment system 100.

[0090] In addition, when the information processing device 300 of the water treatment system 1 of the present embodiment should prioritize reducing the burden on the reuse system 200 rather than reducing the burden on the ammonia treatment system 100, if the upper limit value of the ammonia concentration in the ammonia treatment system 100 is high, based on the amount of ammonia compound required to generate the bactericidal substance, while setting the ammonia concentration in the water to be treated 2 to be achieved by the ammonia treatment system 100 to the target concentration and controlling the PLC 20, if the upper limit value of the ammonia concentration is not high, the upper limit value is set to the target concentration and the PLC 20 is controlled.

[0091] Thus, when the upper limit value of the ammonia concentration in the ammonia treatment system 100 is high, by controlling to maintain the ammonia concentration required to generate the bactericidal substance, the reuse performance of the reuse system 200 can be efficiently improved and its burden can be reduced. On the other hand, when the upper limit value of the ammonia concentration in the ammonia treatment system 100 is low, since it is difficult to expect an improvement in reuse performance, the burden on the ammonia treatment system 100 can be reduced by performing control with the release upper limit value set to the target concentration. In this way, according to the upper limit value of the ammonia concentration in the ammonia treatment system 100, the burden reduction in the ammonia treatment system 100 and the burden reduction in the reuse system 200 can be realized in a well-balanced manner. In this case, it is not necessary to adjust the concentration of the reactant for setting the target concentration of ammonia in the water to be treated 2.

[0092] In addition, when the upper limit value of the ammonia concentration exceeds a predetermined threshold, the information processing device 300 of the water treatment system 1 of the present embodiment calculates the target concentration of the ammonia concentration required to generate the bactericidal substance at a predetermined concentration.

[0093] This can surely suppress the biofouling of the filter unit 204.

[0094] Specifically, the information processing device 300 of the water treatment system 1 of the present embodiment calculates the target concentration of ammonia concentration necessary to generate a bactericidal substance with a concentration of less than 4 mg / L.

[0095] Thereby, while reliably suppressing the biofouling of the filter unit 204, it is possible to prevent the deterioration of the filter unit 204.

[0096] Further, the PLC 20 of the water treatment system 1 of the present embodiment controls the air volume for adjusting the ammonia concentration and the dissolved oxygen concentration of the water to be treated 2.

[0097] Thereby, the ammonia concentration can be adjusted to a desired concentration.

[0098] Further, the ammonia treatment system 100 of the water treatment system 1 of the present embodiment adjusts the ammonia concentration of the water to be treated 2 by at least one of the standard activated sludge method, the carrier sludge method, the membrane separation activated sludge method, or the batch activated sludge method.

[0099] Thereby, the adjustment of the ammonia concentration can be reliably performed.

[0100] Although the embodiments of the present invention have been described as above, the present invention is not limited to the above embodiments, and can be implemented using any components without departing from the gist thereof. The embodiments and modifications described above are merely examples, and the present invention is not limited to these contents as long as the features of the invention are not impaired. Further, although various embodiments and modifications have been described above, the present invention is not limited to these contents. Other aspects conceivable within the scope of the technical idea of the present invention are also included in the scope of the present invention.

[0101] Further, a part of the hardware provided in each device of the present embodiment may be provided in other devices.

[0102] Moreover, each program of each device may be provided in another device, a certain program may be composed of a plurality of programs, or a plurality of programs may be integrated into one program.

[0103] In addition, in this embodiment, the charge (cost) is calculated as the burden amount, but other parameters representing the burden (for example, energy consumption, greenhouse gas generation amount) may be calculated. As items related to the energy consumption amount, the aeration air volume, and for the greenhouse gas generation amount, the greenhouse gas generation amount is calculated from the CO2 generation amount due to power use and the CO2 generation amount due to chemical use. Further, a comprehensive evaluation of the energy reduction effect and the greenhouse gas reduction effect may be used as the burden amount.

[0104] Moreover, the determination formula described in this embodiment is an example, and any formula for comparing the priorities of reducing the burden on the ammonia treatment system 100 and reducing the burden on the reuse system 200 can be adopted.

Explanation of Reference Numerals

[0105] 1 Water treatment system, 10 Aeration tank, 20 PLC, 30 Blower unit, 200 Reuse system, 202 Ammonia addition unit, 203 Reactant introduction unit, 204 Filter unit

Claims

1. An ammonia treatment system comprising a control unit that adjusts the ammonia concentration of water to be treated, and a discharge unit that discharges a part of the water to be treated with the adjusted ammonia concentration, an ammonia addition unit into which reuse target water, which is the water to be treated that has not been discharged by the discharge unit among the water to be treated with the adjusted ammonia concentration, flows, and a predetermined ammonia compound is added to the flowed-in reuse target water, a reactant introduction unit that adds a reactant that generates a predetermined bactericidal substance by reacting with the ammonia compound and the ammonia remaining in the reuse target water to the flowed-in reuse target water, and a reuse system that reuses the reuse target water and includes a filter unit in which biofouling is suppressed by the bactericidal substance contained in the reuse target water and a water treatment system configured to include them.

2. Further comprising an information processing device, the ammonia treatment system includes a control unit that performs control to adjust the ammonia concentration of the water to be treated to a target concentration, and a measurement unit that measures the ammonia concentration of the water to be treated, the information processing device includes a storage device that stores an upper limit value of the ammonia concentration of the water to be treated that can be discharged from the discharge unit, and calculates a first burden amount, which is a burden amount generated in the ammonia treatment system by the control of the control unit, based on the ammonia concentration of the water to be treated measured by the measurement unit, calculates a second burden amount, which is a burden amount generated in the reuse system by the addition of the ammonia compound and the reactant for generating the bactericidal substance, and includes a control device that calculates the target concentration based on the first burden amount and the second burden amount, and controls the control unit so that the ammonia concentration of the water to be treated in the ammonia treatment system becomes the calculated target concentration. The water treatment system according to Claim 1.

3. The information processing device includes a storage device that stores an upper limit value of the ammonia concentration of the water to be treated that can be discharged from the discharge unit. Based on the first load amount and the second load amount, determine whether the reduction of the load on the ammonia treatment system should be prioritized over the reduction of the load on the reuse system. If it is determined that the reduction of the load on the ammonia treatment system should be prioritized over the reduction of the load on the reuse system, set the upper limit value to the target concentration, and control the control unit so that the ammonia concentration of the water to be treated in the ammonia treatment system becomes the set target concentration. The water treatment system according to claim 2.

4. The information processing device is equipped with a storage device that stores the upper limit value of the ammonia concentration of the water to be treated that can be discharged from the discharge unit. Based on the first load amount and the second load amount, determine whether the reduction of the load on the ammonia treatment system should be prioritized over the reduction of the load on the reuse system. If it is determined that the reduction of the load on the ammonia treatment system should not be prioritized over the reduction of the load on the reuse system, determine whether the upper limit value exceeds a predetermined threshold. If the upper limit value exceeds a predetermined threshold, calculate the ammonia concentration of the water to be treated that should be achieved in the ammonia treatment system to generate the sterilizing substance, set the calculated ammonia concentration to the target concentration, and control the control unit so that the ammonia concentration of the water to be treated in the ammonia treatment system becomes the set target concentration. If the upper limit value does not exceed a predetermined threshold, set the upper limit value to the target concentration, and control the control unit so that the ammonia concentration of the water to be treated in the ammonia treatment system becomes the set target concentration. The water treatment system according to claim 2.

5. The information processing device is If the upper limit value exceeds a predetermined threshold, calculate the ammonia concentration of the water to be treated that should be achieved to generate the sterilizing substance at a predetermined concentration. The water treatment system according to claim 4.

6. The information processing device is If the upper limit value exceeds a predetermined threshold, calculate the ammonia concentration of the water to be treated that should be achieved to generate the sterilizing substance at a concentration of less than 4 mg / L. The water treatment system according to claim 5.

7. The control unit controls the air volume for adjusting the ammonia concentration and dissolved oxygen concentration of the water to be treated. The water treatment system according to claim 1.

8. The ammonia treatment system adjusts the ammonia concentration of the water to be treated by at least one of the standard activated sludge method, the carrier sludge method, the membrane separation activated sludge method, or the batch activated sludge method. The water treatment system according to claim 1.

9. An ammonia treatment system is provided, which includes a control unit for adjusting the ammonia concentration of the water to be treated, and a discharge unit for discharging a part of the water to be treated with the adjusted ammonia concentration. An ammonia addition unit, into which reuse target water, which is the water to be treated that has not been discharged by the discharge unit among the water to be treated with the adjusted ammonia concentration, flows, and a predetermined ammonia compound is added to the inflowing reuse target water. A reactant introduction unit that adds a reactant that generates a predetermined bactericidal substance by reacting with the ammonia compound and the ammonia remaining in the reuse target water to the inflowing reuse target water, and A reuse system is provided, which reuses the reuse target water and includes a filter unit in which biofouling is suppressed by the bactericidal substance contained in the reuse target water. Water treatment method.

10. An information processing device is further provided. The ammonia treatment system is provided with a control unit that performs control to adjust the ammonia concentration of the water to be treated to a target concentration, and a measurement unit that measures the ammonia concentration of the water to be treated. The information processing device stores the upper limit value of the ammonia concentration of the water to be treated that can be discharged from the discharge unit, calculates a first burden amount, which is the burden amount generated in the ammonia treatment system by the control of the control unit, based on the ammonia concentration of the water to be treated measured by the measurement unit, calculates a second burden amount, which is the burden amount generated in the reuse system by the addition of the ammonia compound and the reactant for generating the bactericidal substance, calculates the target concentration based on the first burden amount and the second burden amount, and controls the control unit so that the ammonia concentration of the water to be treated in the ammonia treatment system becomes the calculated target concentration. The water treatment method according to claim 9.

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