Wastewater treatment method

Abstract

The invention provides a wastewater treatment method capable of stably performing wastewater treatment. According to the wastewater treatment method of the present embodiment, wastewater flows into an adjustment tank, and water is fed from the adjustment tank to a wastewater treatment facility, in which water quality items or operation management items relating to a wastewater load are measured continuously or periodically, and the measured items are subjected to water quality control. The drainage load of a drainage inflow part (drainage treatment inflow part) of the drainage treatment equipment is estimated by using a preset calculation formula on the basis of the measured value, the drainage is supplied to the adjustment tank when the estimated drainage load is less than a predetermined threshold value, and the drainage is supplied to the adjustment tank when the estimated drainage load is greater than or equal to the threshold value. The discharged water is branched at a discharged water branching position on the upstream side of the adjustment tank and stored in a high-load adjustment tank.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for treating drainage, which estimates a drainage load of a drainage treatment inflow section, distributes high-load drainage to other tanks based on the estimated drainage load so that the drainage treatment does not fail, and supplies water to the high-load drainage at a timing when the drainage load is low, thereby stabilizing the drainage treatment. BACKGROUND

[0002] Drainage discharged from a manufacturing plant of beverages, foods, or the like varies greatly in concentration or drainage amount depending on the type or amount of manufactured products, the cleaning elapsed time of a production line, or the like. Depending on the load of the drainage, the appropriate operating conditions of the drainage treatment also vary greatly, and in the case where the load of the drainage varies greatly, the treatment conditions are sometimes affected.

[0003] In particular, in organic drainage, biological treatment such as aerobic treatment or anaerobic treatment is generally performed as drainage treatment, but if the drainage load is large, the biological treatment capacity can be exceeded, and problems such as biological treatment failure or deterioration of treated water quality can occur.

[0004] In addition, in treatment based on the Fenton reaction or treatment based on physical-chemical treatment such as adsorption, the required amount of a reagent or an adsorbent varies, and therefore it is important to grasp the variation in the load of drainage flowing into a treatment device.

[0005] Conventionally, an operator periodically collects and analyzes drainage to thereby grasp the drainage load of a drainage treatment inflow section, and manually performs emergency measures such as emergency dilution to other tanks, dilution, reduction of the inflow amount to the drainage treatment, or the like when high-load drainage flows in. However, in the method, since the measurement is always performed manually, continuous measurement cannot be performed, and sometimes the inflow of high-load drainage is missed, or the measures are delayed, resulting in drainage treatment failure or deterioration of treated water quality. Therefore, it is important to continuously grasp the load of inflowing drainage and take measures as early as possible so that the drainage treatment does not fail.

[0006] In Patent Literature 1, a drainage treatment device that achieves stabilization of drainage treatment by distributing treatment processes according to the concentration is disclosed. Specifically, drainage is distributed into high-concentration drainage and low-concentration drainage based on the measured conductivity of the drainage. However, in the conductivity measured by the method, it is difficult to sufficiently evaluate a dirty substance having low conductivity. Furthermore, high-concentration drainage and low-concentration drainage are distinguished as high concentration or low concentration by comparison between the two, and are not limited by a numerical value. In this method, depending on the water quality of the drainage, the judgment of high concentration or low concentration also varies. For example, in the case where high-concentration drainage continues for a long time, drainage having a concentration that can affect the treatment of drainage in the latter stage can be distinguished as low-concentration drainage.

[0007] Patent Literature 1: Japanese Patent Application Laid-Open No. 2002-282889 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] An object of the present application is to provide a drainage treatment method capable of stably performing drainage treatment.

[0010] MEANS FOR SOLVING THE PROBLEMS

[0011] [1] A drainage treatment method of flowing drainage into an adjustment tank, and feeding water from the adjustment tank to a drainage treatment facility, wherein a water quality item or an operation management item related to a drainage load is measured continuously or periodically, a drainage load to a drainage inflow portion (drainage treatment inflow portion) of the drainage treatment facility is estimated based on a measured value using a preset calculation formula, the drainage is supplied to the adjustment tank when the estimated drainage load is less than a prescribed threshold value, and the drainage is branched at a drainage branching position on an upstream side of the adjustment tank to be stored in a high-load adjustment tank when the estimated drainage load is equal to or more than the threshold value.

[0012] [2] The drainage treatment method according to [1], wherein the water quality item or the operation management item related to the drainage load includes a pollution load of the drainage or an item related to the pollution load, and a drainage flow rate flowing into the drainage treatment facility.

[0013] [3] The drainage treatment method according to [1] or [2], wherein the drainage is fed from the high-load adjustment tank when the drainage load becomes equal to or less than a prescribed threshold value when the drainage is merged on a more downstream side than the drainage branching position from the high-load adjustment tank.

[0014] [4] The drainage treatment method according to [3], wherein the drainage is fed from the high-load adjustment tank and merged on a downstream side of the adjustment tank.

[0015] [5] The drainage treatment method according to [3], wherein the drainage is fed from the high-load adjustment tank to the adjustment tank.

[0016] EFFECTS OF THE INVENTION

[0017] With the present application, it is possible to stably perform drainage treatment. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a schematic configuration view of a drainage treatment system of a related art.

[0019] Figure 2 is a schematic configuration view of a drainage treatment system of a related art.

[0020] Figure 3 is a schematic configuration diagram of a drainage treatment system of the related art.

[0021] Figure 4 is a schematic configuration diagram of a drainage treatment system of an embodiment of the present application.

[0022] Figure 5 is a schematic configuration diagram of a drainage treatment system of the embodiment.

[0023] Figure 6 is a schematic configuration diagram of a drainage treatment system of the related art.

[0024] Figure 7 is a schematic configuration diagram of a drainage treatment system of an embodiment of the present application.

[0025] Figure 8 is a schematic configuration diagram of a drainage treatment system of the embodiment.

[0026] Figure 9 is a schematic configuration diagram of a drainage treatment system of the embodiment.

[0027] Figure 10 is a schematic configuration diagram of a drainage treatment system of the embodiment.

[0028] Figure 11 is a schematic configuration diagram of a drainage treatment system of the related art.

[0029] Figure 12 is a schematic configuration diagram of a drainage treatment system of the related art.

[0030] Figure 13 is a schematic configuration diagram of a drainage treatment system of an embodiment of the present application.

[0031] Figure 14 is a schematic configuration diagram of a drainage treatment system of the embodiment. DETAILED DESCRIPTION

[0032] A drainage treatment system of an embodiment of the present application receives drainage in an adjustment tank, transports the drainage from the adjustment tank to a drainage treatment facility, measures a soiled load on an upstream side compared to the adjustment tank, a flow rate of the drainage flowing into the adjustment tank, and a flow rate of the drainage flowing into the drainage treatment facility, respectively, and estimates a drainage load of an inflow portion (hereinafter also referred to as "drainage treatment inflow portion") of the drainage treatment facility using the same. In addition, high-load drainage is distributed to other tanks based on the estimated drainage load so that the drainage treatment does not fail, and the high-load drainage is transported at a time when the drainage load is low, thereby stabilizing the drainage treatment.

[0033] There may be one or more regulating tanks. As described below, multiple regulating tanks 1 can be configured in parallel or in series. There are no particular limitations on the volume or other specifications of the regulating tanks. Furthermore, there are no particular limitations on the treatment method or the number of systems in the wastewater treatment equipment. Examples of treatment methods include, for instance, so-called biological treatment, Fenton treatment, or activated carbon treatment, which may involve aerobic or anaerobic processes.

[0034] Next, the method for estimating the drainage load of the drainage treatment inlet section will be explained based on the accompanying drawings.

[0035] like Figure 1 As shown, in the case where the drainage treatment system includes an adjustment tank 1 and a drainage treatment device 3 installed at the downstream end of the adjustment tank 1, the turbidity load of the drainage is measured by a turbidity load measuring unit 4 installed at the upstream end of the adjustment tank 1. Furthermore, a first flow measuring unit 5 is used to measure the flow rate of the drainage flowing into the adjustment tank 1, and a second flow measuring unit 10 is used to measure the flow rate of the drainage flowing into the drainage treatment device 3.

[0036] The purpose of the adjustment tank 1 is to adjust and mitigate changes in water quality or quantity, and it has a hydraulic retention time (HRT) of more than 30 minutes.

[0037] In this embodiment, an example of measuring the total organic carbon (TOC) concentration as a pollutant load is described. However, the measured item is not limited to TOC concentration; other indicators representing pollutant load, such as chemical oxygen demand (COD) concentration or suspended solids (SS) concentration, may also be used. Furthermore, the pollutant load measuring unit 4 may measure items related to pollutant load, such as conductivity or Brix sugar content.

[0038] The first flow measurement unit 5 can use a flow meter (FI). When the adjusting tank 1 is filled with water in batches, the first flow measurement unit 5 can calculate the flow rate of the drainage flowing into the adjusting tank 1 based on the increase in water level in the adjusting tank 1 per unit time. Alternatively, when the adjusting tank 1 is filled with water continuously, the flow rate of the drainage flowing into the adjusting tank 1 can be calculated based on the sum of the change in the storage volume of the adjusting tank 1 and the discharge flow rate from the adjusting tank.

[0039] The second flow measurement unit 10 can use a flow meter (FI). When the adjustment tank 1 is filled with water in batches, the second flow measurement unit 10 can calculate the flow rate of the drainage flowing into the drainage treatment equipment 3 based on the amount of water level reduction in the adjustment tank 1 per unit time.

[0040] The turbidity load measuring unit 4, the first flow rate measuring unit 5, and the second flow rate measuring unit 10 continuously or periodically at relatively short time intervals measure the turbidity load or related items as water quality items or operation and management items related to the drainage load, the flow rate of drainage flowing into the regulating tank 1, and the flow rate of drainage flowing into the drainage treatment system.

[0041] The calculation unit 6 uses the TOC concentration measured by the turbidity load measuring unit 4 and the flow rate measured by the first flow rate measuring unit 5 to estimate the TOC concentration in the wastewater treatment inlet (outlet of the adjusting tank 1). In addition, the calculation unit 6 uses the estimated TOC concentration and the flow rate measured by the second flow rate measuring unit 10 to estimate the wastewater load (kg-TOC / day) of the wastewater treatment inlet.

[0042] The method of estimating the TOC concentration in the wastewater treatment inflow section using the TOC concentration measured by the turbidity load measuring unit 4 and the flow rate measured by the first flow rate measuring unit 5 can be carried out by various proposed concentration calculation models for stagnant water tanks. However, depending on whether the adjustment tank 1 is continuously or partially circulated, different estimation methods as shown below can be used.

[0043] <When water is continuously flowing>

[0044] Presumption method (1)-1

[0045] The TOC concentration (mg / L) of the wastewater treatment inflow section is estimated by performing a moving average on the TOC concentration measured on the upstream side of the adjustment tank 1 over a period close to the residence time in the adjustment tank 1. For example, when the residence time in the adjustment tank 1 is 50 minutes, the average of the TOC concentration measurements from the present to 50 minutes ago can be regarded as the TOC concentration of the wastewater treatment inflow section (discharged from the adjustment tank 1).

[0046] Presumption method (2)-1

[0047] Based on the TOC concentration and flow rate measured upstream of the adjustment tank 1, the change in the concentration of wastewater flowing into the adjustment tank 1 is estimated using a fully mixed tank model, thereby estimating the TOC concentration (mg / L) at the wastewater treatment inlet.

[0048] <During phased water supply>

[0049] Presumption method (3)-1

[0050] The total TOC weight (g) flowing into the equalization tank 1 divided by the total water volume (m³) flowing into the equalization tank 1 3 The estimated TOC concentration (mg / L) in the wastewater inflow section was determined.

[0051] To accurately determine the total TOC weight or total water volume flowing into the regulating tank 1, it is ideal to obtain the opening / closing signal of the regulating tank inlet valve or the start / stop signal of the pump, and calculate the load by accumulating the TOC concentration and water volume during the time the inlet valve is "open" to "closed" or the pump is operating. If it is difficult to obtain valve opening / closing signals or pump start / stop signals, the timing of drainage flowing into the regulating tank 1 can also be determined based on changes in the water level of the regulating tank 1.

[0052] The calculation unit 6 estimates the drainage load (kg-TOC / day) based on the TOC concentration of the drainage treatment inflow section estimated by any one of the estimation methods (1)-1, (2)-1, and (3)-1, and the flow rate of the drainage treatment inflow section measured by the second flow measurement unit 10.

[0053] Formula 1: Drainage load (kg - TOC / day) = TOC concentration at the drainage treatment inlet (mg / L) × Flow rate at the drainage treatment inlet (m³ / h) × 24h / 1000

[0054] like Figure 2 As shown, when an adjusting tank 2 is arranged in series with the drainage treatment equipment 3, the TOC concentration (estimated value A) at the outlet of adjusting tank 1 is first estimated. More than one adjusting tank 2 may be installed; as described later, multiple adjusting tanks 2 may also be configured in parallel. The volume and other specifications of the adjusting tank 2 are not particularly limited. Figure 1 Similarly, depending on whether the adjustment tank 1 is continuously or partially circulated, the estimation method is different. In the case of continuous water circulation, the estimation method (1)-1 or estimation method (2)-1 is used to estimate the TOC concentration (estimated value A) at the outlet of the adjustment tank 1. In the case of partial water circulation, the estimation method (3)-1 is used to estimate the TOC concentration (estimated value A) at the outlet of the adjustment tank 1.

[0055] Next, based on the TOC concentration (estimated value A) at the outlet of the regulating tank 1 as determined as described above and the flow rate of the drainage flowing into the regulating tank 2 measured by the third flow measurement unit 8, the TOC concentration (estimated value B) at the drainage treatment inlet (outlet of the regulating tank 2) is estimated. Here, the estimation method differs depending on whether the regulating tank 2 is continuously or partially circulated. In the case of continuous water circulation, the following estimation method (1)-2 or estimation method (2)-2 is used to estimate the TOC concentration (estimated value B) at the drainage treatment inlet. In the case of partial water circulation, estimation method (3)-2 is used to estimate the TOC concentration (estimated value B) at the drainage treatment inlet.

[0056] Presumption method (1)-2

[0057] The TOC concentration (mg / L) at the wastewater treatment inlet is estimated by moving average the TOC concentration (estimated value A) over a period of time close to the residence time in the adjustment tank 2.

[0058] Presumption method (2)-2

[0059] Based on the TOC concentration (estimated value A) and the flow rate into the adjustment tank 2, the change in the concentration of the wastewater flowing into the adjustment tank 2 is estimated using a fully mixed tank model, thereby estimating the TOC concentration (mg / L) at the wastewater treatment inlet.

[0060] Presumption method (3)-2

[0061] By dividing the total TOC weight (g) flowing into the equalization tank 2 by the total water volume (m³) flowing into the equalization tank 2... 3 The estimated TOC concentration (mg / L) in the wastewater inflow section was determined.

[0062] The third flow measurement unit 8, which measures the flow rate of the drainage flowing into the regulating tank 2, can be a flow meter. When the regulating tank 2 is circulated with water in batches, the flow rate of the drainage flowing into the regulating tank 2 can be calculated based on the increase in water level in the regulating tank 2 per unit time. Alternatively, when the regulating tank 2 is circulated with water continuously, the flow rate of the drainage flowing into the regulating tank 2 can be calculated based on the sum of the change in the storage volume of the regulating tank 2 and the discharge flow rate from the regulating tank.

[0063] Based on the TOC concentration (estimated value B) of the drainage treatment inlet obtained in this way and the flow rate of the drainage treatment inlet measured by the second flow measurement unit 10, the drainage load (kg-TOC / day) is estimated using the above formula 1.

[0064] Next, as Figure 3 As shown, consider the scenario where adjusting tanks 2A and 2B are connected in parallel between adjusting tank 1 and drainage treatment equipment 3, with drainage being returned from adjusting tank 2B to adjusting tank 1. Drainage flowing out of adjusting tank 1 flows into adjusting tank 2A ​​or adjusting tank 2B. Drainage flowing out of adjusting tank 2A ​​flows into drainage treatment equipment 3. Drainage flowing out of adjusting tank 2B is returned to adjusting tank 1.

[0065] The fourth flow measurement unit 13 measures the flow rate of the drainage flowing into the adjusting tank 2B. This can be done using a flow meter or calculated based on the increase in water level in the adjusting tank 2B per unit time. The fifth flow measurement unit 15 measures the flow rate of the drainage returning from the adjusting tank 2B to the adjusting tank 1. This can be done using a flow meter or calculated based on the decrease in water level in the adjusting tank 2B per unit time.

[0066] In this case, the condition for the adjusting tank 2B that returns drainage to the adjusting tank 1 is that water is supplied in batches. The adjusting tank 1 and the adjusting tank 2A ​​can be either continuously supplied or supplied in batches. More than one adjusting tank 2A ​​can be set, and multiple adjusting tanks 2A can also be configured in parallel.

[0067] First, based on the TOC concentration measured on the upstream side of the adjustment tank 1 and the flow rate measured by the fourth flow measurement unit 13, the TOC concentration of the drainage in the adjustment tank 2B (estimated value C) is estimated by the following estimation method (3)-3.

[0068] Presumption method (3)-3

[0069] By dividing the total TOC weight (g) flowing into the adjusting tank 2B by the total water volume (m³) flowing into the adjusting tank 2B... 3 The estimated TOC concentration (mg / L) of the adjustment tank 2B was determined.

[0070] Next, based on the TOC concentration (estimated value C) of the adjustment tank 2B as described above, the flow rate measured by the fifth flow measurement unit 15, and the TOC concentration and flow rate measured on the upstream side of the adjustment tank 1, the TOC concentration (estimated value D) at the outlet of the adjustment tank 1 is estimated. When the adjustment tank 1 is continuously filled with water, the estimation is performed by estimation method (2)-3, and when the adjustment tank 1 is filled with water in batches, the estimation is performed by estimation method (3)-4.

[0071] Presumption method (2)-3

[0072] Based on the TOC concentration and flow rate measured upstream of the regulating tank 1, the TOC concentration (estimated value C) of the regulating tank 2B, and the flow rate flowing from the regulating tank 2B into the regulating tank 1, the change in the concentration of the wastewater flowing into the regulating tank 1 is estimated using a fully mixed tank model, thereby estimating the TOC concentration (mg / L) at the outlet of the regulating tank 1.

[0073] Presumption method (3)-4

[0074] By dividing the total TOC weight (g) flowing into the equalization tank 1 by the total water volume (m³) flowing into the equalization tank 1... 3 The estimated TOC concentration (mg / L) at the outlet of equalization tank 1 is calculated. The total TOC weight and total water volume are calculated by adding the TOC weight and water volume measured on the upstream side of equalization tank 1 to the TOC weight and water volume returned from equalization tank 2B.

[0075] Next, based on the TOC concentration (estimated value D) at the outlet of the regulating tank 1 as determined as described, and the flow rate into the regulating tank 2A, the TOC concentration (estimated value E) at the drainage treatment inlet (outlet of the regulating tank 2A) is estimated. When the regulating tank 2A ​​is continuously circulated, the TOC concentration (estimated value E) at the drainage treatment inlet is estimated using estimation method (1)-3 or estimation method (2)-4. When the regulating tank 2A ​​is partially circulated, the TOC concentration (estimated value E) at the drainage treatment inlet is estimated using estimation method (3)-5.

[0076] Presumption method (1)-3

[0077] The TOC concentration (mg / L) at the wastewater treatment inlet was estimated by moving average the TOC concentration (estimated value D) over a period close to the residence time in the adjustment tank 2A.

[0078] Presumption method (2)-4

[0079] Based on the TOC concentration (estimated value D) and the flow rate into the adjustment tank 2A, the change in the concentration of wastewater flowing into the adjustment tank 2A ​​is estimated using a fully mixed tank model, thereby estimating the TOC concentration (mg / L) at the wastewater treatment inlet.

[0080] Presumption method (3)-5

[0081] By dividing the total TOC weight (g) flowing into the equalization tank 2A ​​by the total water volume (m³) flowing into the equalization tank 2A... 3 The estimated TOC concentration (mg / L) in the wastewater inflow section was determined.

[0082] Based on the TOC concentration (estimated value E) of the drainage treatment inlet obtained in this way and the flow rate of the drainage treatment inlet measured by the second flow measurement unit 10, the drainage load (kg-TOC / day) is estimated using the above formula 1.

[0083] According to this embodiment, the sludge load (or a sludge load-related item) on the upstream side of the regulating tank 1, the flow rate of drainage flowing into the regulating tank, and the flow rate of drainage flowing into the drainage treatment equipment are measured respectively, and these are used to estimate the drainage load of the drainage treatment inlet section. The inflow rate to the drainage treatment is controlled based on the estimated value, or high-load drainage is allocated to a high-load regulating tank (see reference). Figure 4 , Figure 5 , Figures 7-10 , Figure 13 , Figure 14 This can stabilize the drainage treatment process.

[0084] A threshold is set for the estimated drainage load. When the drainage load exceeds the threshold, it is allocated to the high-load adjustment tank; when it falls below the threshold, it is allocated to the normal adjustment tank. The threshold is set under the condition that drainage treatment will not fail, such as being below the design reference value of the downstream drainage treatment equipment. In addition to adding the current drainage load, the drainage load of drainage that passed several hours ago can also be added to the threshold determination. For example, if the current drainage load exceeds the set threshold A, and the drainage load several hours ago exceeds the set threshold B, it can be allocated to the high-load adjustment tank. Ideally, the threshold should be preset according to the site conditions.

[0085] When water is supplied from the high-load regulating tank and mixed with drainage, if the drainage load from the high-load regulating tank is added to the drainage load of the drainage treatment inflow section, water is supplied from the high-load regulating tank if the load is less than a set threshold. Conversely, if the combined load exceeds the threshold, no water is supplied and the water remains stored in the high-load regulating tank.

[0086] The following describes specific examples of the distribution method to the high-load adjustment tank and the water supply method from the high-load adjustment tank.

[0087] Figure 4 Indicates in Figure 1 The drainage treatment system shown includes a high-load adjustment tank 12. Figure 4 In the structure shown, the high-load regulating tank 12 is configured in parallel with the regulating tank 1. The drainage delivered by the transfer pump 11 branches on the upstream side of the regulating tank 1, and the flow into either the regulating tank 1 or the high-load regulating tank 12 can be switched by controlling the opening and closing of valves 17A and 17B.

[0088] The calculation unit 6 obtains the TOC concentration measured by the turbidity load measuring unit 4 and the flow rate measured by the first flow rate measuring unit 5, and estimates the TOC concentration of the wastewater treatment inflow section using any one of the estimation methods (1)-1, (2)-1, and (3)-1. In addition, the calculation unit 6 uses the estimated TOC concentration and the flow rate measured by the second flow rate measuring unit 10 to estimate the wastewater load of the wastewater treatment inflow section and determine whether there is a problem with the flow into the wastewater treatment equipment 3.

[0089] Normally, drainage flows into the regulating tank 1. When the calculation unit 6 determines that the estimated drainage load exceeds a predetermined threshold and that drainage treatment may fail, it closes valve 17A and opens valve 17B, distributing the drainage to the high-load regulating tank 12. After switching the drainage's destination to the high-load regulating tank 12, drainage is also pumped from the regulating tank 1 to the drainage treatment equipment 3 via the transfer pump 20. The calculation unit 6 continues to estimate the TOC concentration and drainage load of the drainage treatment inflow.

[0090] Subsequently, when the estimated drainage load is less than a threshold, the destination of the drainage flow is switched from the high-load adjustment tank 12 to the adjustment tank 1. Furthermore, the calculation unit 6 controls the transfer pump 19, adjusting the timing of delivering high-load drainage from the high-load adjustment tank 12 to the drainage treatment equipment 3 to prevent drainage treatment failure. When the drainage load at the downstream side of the adjustment tank 1, where the drainage from the adjustment tank 1 and the drainage from the high-load adjustment tank 12 are mixed (merged), is less than a predetermined threshold, the calculation unit 6 delivers water from the high-load adjustment tank 12. When the combined drainage load is above the threshold, water is not delivered from the high-load adjustment tank 12 and the system remains in a stored state.

[0091] The calculation unit 6 can display the opening and closing timing of valves 17A and 17B on a monitor screen, allowing operators to manually control the opening and closing of valves 17A and 17B according to the display. Similarly, the calculation unit 6 can also display the water delivery timing of transfer pumps 19 and 20 on a monitor screen, allowing operators to manually start the pumps according to the display. Alternatively, a transfer pump can be installed downstream of the confluence point instead of transfer pumps 19 and 20, with a switching valve installed before the drainage from the regulating tank 1 and the high-load regulating tank merges, allowing operation with a single transfer pump.

[0092] exist Figure 4 The structure shown describes the process of conveying drainage from the high-load regulating tank 12 to the drainage treatment equipment 3, but it can also be described as follows: Figure 5 As shown, the drainage in the high-load adjustment tank 12 is transported to the adjustment tank 1.

[0093] exist Figure 6 In the structure shown, drainage is arbitrarily delivered to regulating tank 1 and regulating tank 1' without considering the turbidity load of the drainage. When delivering drainage to regulating tank 1, valve 7A is opened and valve 7B is closed; when delivering drainage to regulating tank 1', valve 7A is closed and valve 7B is opened. Additionally, drainage is delivered from the regulating tank (which does not deliver drainage) to the drainage treatment equipment 3 in regulating tanks 1 and 1'. When the calculation unit 6 determines that the drainage load is high and drainage treatment may fail, it controls transfer pumps 19' and 20' to adjust the flow rate of drainage delivered from regulating tanks 1 and 1' to a drainage load (TOC concentration × flow rate) that ensures drainage treatment will not fail. The calculation unit 6 can also display the water delivery volume of transfer pumps 19' and 20' on a monitor screen, etc., and the operator manually starts the pumps according to the display. Alternatively, a transfer pump can be installed downstream of the confluence point instead of transfer pumps 19' and 20', and a switching valve can be installed before the drainage from adjustment tank 1 and high-load adjustment tank 12 merges, so that one transfer pump can operate.

[0094] Figure 7 Indicates and Figure 2 The drainage treatment system shown has a structure in which the adjusting tank 2 is connected in parallel with the high-load adjusting tank 12. By controlling the opening and closing of valves 7A and 7B, it is possible to switch which of the adjusting tanks 2 and the high-load adjusting tank 12 the drainage delivered from the adjusting tank 1 flows into.

[0095] The calculation unit 6 obtains the TOC concentration measured by the turbidity load measuring unit 4 and the flow rate measured by the first flow measuring unit 5, and estimates the TOC concentration at the outlet of the adjustment tank 1 by any one of the estimation methods (1)-1, estimation method (2)-1, and estimation method (3)-1.

[0096] The calculation unit 6 uses the estimated TOC concentration at the outlet of the adjustment tank 1 and the flow rate of the drainage flowing into the adjustment tank 2 measured by the third flow measurement unit 8 to estimate the TOC concentration of the drainage treatment inlet using any one of the estimation methods (1)-2, (2)-2, and (3)-2. Furthermore, the calculation unit 6 estimates the drainage load of the drainage treatment inlet using Equation 1 based on the estimated TOC concentration of the drainage treatment inlet and the flow rate of the drainage treatment inlet measured by the second flow measurement unit 10.

[0097] Normally, drainage from regulating tank 1 flows into regulating tank 2. When the calculation unit 6 determines that the estimated drainage load exceeds a predetermined threshold and that drainage treatment may fail, it closes valve 7A and opens valve 7B, causing the drainage from regulating tank 1 to flow into high-load regulating tank 12. After switching the drainage's destination to high-load regulating tank 12, drainage is also pumped from regulating tank 2 to drainage treatment equipment 3 via transfer pump 20. The calculation unit 6 continues to estimate the TOC concentration at the outlet of regulating tank 1, the TOC concentration at the drainage treatment inlet, and the drainage load.

[0098] Subsequently, when the estimated drainage load is less than a threshold, the destination of the drainage flow is switched from the high-load adjustment tank 12 to the adjustment tank 2. Furthermore, the calculation unit 6 controls the transfer pump 19, adjusting the timing of delivering high-load drainage from the high-load adjustment tank 12 to the drainage treatment equipment 3 to prevent drainage treatment failure. The calculation unit 6 delivers water from the high-load adjustment tank 12 when the drainage load when the drainage from the adjustment tank 2 and the drainage from the high-load adjustment tank 12 is less than a predetermined threshold. When the mixed drainage load is above the threshold, water is not delivered from the high-load adjustment tank 12 and the system remains in a stored state.

[0099] exist Figure 7 In the structure, the opening and closing of valves 7A and 7B are controlled to switch the destination of the drainage delivered from the adjusting tank 1, but it can also be done as follows: Figure 8As shown, a transfer pump 18A is installed to deliver water from the adjustment tank 1 to the adjustment tank 2, and a transfer pump 18B is installed to deliver water from the adjustment tank 1 to the high-load adjustment tank 12. The start and stop of transfer pumps 18A and 18B are controlled to switch which of the two tanks, adjustment tank 2 and high-load adjustment tank 12, the drainage flows into. The calculation unit 6 can also display the start and stop times of transfer pumps 18A and 18B on a monitor screen or other display, so that the operator can manually start the pumps according to the display.

[0100] exist Figure 7 The structure shown describes a configuration where drainage from the high-load adjustment tank 12 is transferred to the drainage treatment equipment 3 when the drainage load decreases. However, it is also possible to use a different configuration. Figure 9 As shown, the drainage in the high-load adjustment tank 12 is transported to the adjustment tank 2.

[0101] exist Figure 9 In the structure, the opening and closing of valves 7A and 7B are controlled, switching the destination of the drainage delivered from the adjusting tank 1. However, it can also be done as follows: Figure 10 As shown, a transfer pump 18A is provided to deliver water from the adjustment tank 1 to the adjustment tank 2, and a transfer pump 18B is provided to deliver water from the adjustment tank 1 to the high-load adjustment tank 12. The start and stop of the transfer pumps 18A and 18B are controlled to switch which one the drainage from the adjustment tank 1 flows into, the adjustment tank 2 or the high-load adjustment tank 12.

[0102] exist Figures 7-10 In the structure shown, drainage that branches off downstream of the regulating tank 1 and is presumed to have a drainage load exceeding a specified value is distributed to a high-load regulating tank 12, which is connected in parallel with the regulating tank 2. When the drainage branches off upstream of the regulating tank 1 and is distributed to the high-load regulating tank 12, the drainage quality fluctuates drastically and is frequently distributed to the high-load regulating tank 12. Therefore, operations involving valve opening and closing or transfer pump start / stop, especially in manual operation, may impose a load on operational responses. Therefore, it is preferable to distribute the drainage to the high-load regulating tank 12 downstream of the regulating tank 1 for the purpose of simplifying the distribution operation.

[0103] It should be noted that, Figures 7-10 The HRT (High-Resolution Time) of the equalization tank 1 is preferably 30 to 60 minutes. It can be considered that when the HRT is below 60 minutes, the water quality equalization function of the equalization tank 1 is low, and the distribution frequency or effect is unlikely to differ regardless of where the branch from the equalization tank 1 upstream or downstream to the high-load equalization tank 12 is located. Therefore, in this case, it is ideal to set up the equalization tank 2 and the high-load equalization tank in parallel by branching from the downstream side of the equalization tank 1 to achieve water quality equalization or high-load drainage distribution.

[0104] Furthermore, the HRT (Heat Retention Time) of the equalization tank 2 is preferably about 60 minutes to 30 hours. If the HRT is 60 minutes or more, the water quality can be considered sufficiently equalized. Even if equalization has been achieved, if the estimated drainage load exceeds the specified value, the drainage treatment can be stabilized by pre-allocating the wastewater to the high-load equalization tank 12. On the other hand, if the HRT exceeds 30 hours, the possibility of the drainage load exceeding the specified value is low, and it can be considered unnecessary to allocate the drainage to the high-load equalization tank 12.

[0105] exist Figure 11 In the structure shown, the wastewater is arbitrarily transported to regulating tank 2 and regulating tank 2' without considering the sewage load. When transporting wastewater to regulating tank 2, valve 7A is opened and valve 7B is closed; when transporting wastewater to regulating tank 2', valve 7A is closed and valve 7B is opened. Additionally, wastewater is transported from the regulating tank (which does not transport wastewater) to the wastewater treatment equipment 3 in regulating tanks 2 and 2'. Alternatively, it can be done as follows... Figure 12 As shown, a transfer pump 18A that supplies water from adjustment tank 1 to adjustment tank 2 and a transfer pump 18B that supplies water from adjustment tank 2 to adjustment tank 2' are provided, and the pumps are switched on and off. When the calculation unit 6 determines that the drainage load is high and the drainage treatment may fail, it controls the transfer pumps 19' and 20' to adjust the flow rate of the drainage delivered from adjustment tank 2 and adjustment tank 2' to a drainage load (TOC concentration × flow rate) that will prevent the drainage treatment from failing.

[0106] Figure 13 Indicates will Figure 3 The drainage treatment system shown has adjustment tanks 2A and 2B configured as adjustment tank 2 and high-load adjustment tank 12, respectively. By controlling the opening and closing of valves 7A and 7B, the drainage from adjustment tank 1 can be switched to flow into either adjustment tank 2 or high-load adjustment tank 12.

[0107] The calculation unit 6 obtains the TOC concentration measured by the turbidity load measurement unit 4 and the flow rate of the drainage flowing into the high load adjustment tank 12 measured by the fourth flow measurement unit 13, and estimates the TOC concentration of the high load adjustment tank 12 by the estimation method (3)-3.

[0108] The calculation unit 6 uses the estimated TOC concentration of the high-load adjustment tank 12, the flow rate measured by the fifth flow measurement unit 15, the TOC concentration measured by the turbidity load measurement unit 4, and the flow rate measured by the first flow measurement unit 5 to estimate the TOC concentration at the outlet of the adjustment tank 1 by the estimation method (2)-3 or the estimation method (3)-4.

[0109] Next, the calculation unit 6 uses the estimated TOC concentration at the outlet of the adjustment tank 1 and the flow rate of the drainage flowing into the adjustment tank 2 measured by the third flow measurement unit 8 to estimate the TOC concentration of the drainage treatment inflow section (outlet of the adjustment tank 2) by any one of the estimation methods (1)-3, estimation methods (2)-4, and estimation methods (3)-5.

[0110] Furthermore, the calculation unit 6 estimates the drainage load using Equation 1 based on the estimated TOC concentration of the drainage treatment inflow and the flow rate of the drainage treatment inflow measured by the second flow measurement unit 10.

[0111] Normally, drainage from regulating tank 1 flows into regulating tank 2. When the calculation unit 6 determines that the estimated drainage load exceeds a predetermined threshold and drainage treatment may fail, it closes valve 7A and opens valve 7B, allowing drainage from regulating tank 1 to flow into high-load regulating tank 12. After switching the drainage's destination to high-load regulating tank 12, drainage is also pumped from regulating tank 2 to drainage treatment equipment 3 via transfer pump 20, and the calculation unit 6 continues to estimate the drainage load.

[0112] Subsequently, when the estimated drainage load is less than a threshold, the destination of the drainage is switched from the high-load adjustment tank 12 to the adjustment tank 2. Furthermore, the calculation unit 6 controls the transfer pump 19, adjusting the timing of delivering high-load drainage from the high-load adjustment tank 12 to the adjustment tank 1 to prevent drainage processing failure. If the drainage load when returning drainage from the high-load adjustment tank 12 to the adjustment tank 1 is less than a predetermined threshold, the calculation unit 6 delivers water from the high-load adjustment tank 12 to the adjustment tank 1. If the drainage load becomes above the threshold due to the return flow, water is not delivered from the high-load adjustment tank 12 and the tank remains stored.

[0113] exist Figure 13 In the structure, the opening and closing of valves 7A and 7B are controlled, switching the destination of the drainage delivered from the adjusting tank 1. However, it can also be done as follows: Figure 14 As shown, a transfer pump 18A is set up to deliver water from the adjustment tank 1 to the adjustment tank 2, and a transfer pump 18B is set up to deliver water from the adjustment tank 1 to the high-load adjustment tank 12. The start and stop of the transfer pump 18A and the transfer pump 18B are controlled to switch which one the drainage from the adjustment tank 1 flows into, the adjustment tank 2 or the high-load adjustment tank 12.

[0114] According to this embodiment configured as described above, by allocating high-load drainage exceeding a predetermined threshold to the high-load adjustment tank, the drainage load of the subsequent drainage treatment can be kept below a predetermined value. For the drainage allocated to the high-load adjustment tank, by mixing it with the raw water in a manner not exceeding a predetermined threshold, treatment can be performed while ensuring that the drainage load of the subsequent drainage treatment does not exceed a predetermined value. Therefore, stabilization of the drainage treatment can be expected.

[0115] In the above embodiment, the structure in which the calculation unit 6 performs calculations such as estimating the turbidity load of the drainage treatment inlet and the drainage load of the drainage treatment inlet is described. However, the calculation unit 6 may be composed of a single computer or may be distributed by multiple computers.

[0116] The present invention has been described in detail using specific methods, but those skilled in the art will recognize that various modifications can be made without departing from the intent and scope of the invention.

[0117] This application is based on Japanese Special Application 2023-120083, filed on July 24, 2023, and its entire contents are incorporated herein by reference.

[0118] Explanation of reference numerals in the attached figures

[0119] 1, 2, 2': Adjustment slots.

[0120] 3: Drainage treatment equipment.

[0121] 4: Turbidity load measurement section.

[0122] 5: First flow measurement section.

[0123] 6: Arithmetic unit.

[0124] 8: Third flow measurement section.

[0125] 10: Second flow measurement section.

[0126] 11, 19, 19', 20, 20': Transfer pumps.

[0127] 12: High-load adjustment tank.

[0128] 13: Fourth Flow Measurement Section.

[0129] 15: Fifth Flow Measurement Section.

Claims

1. A drainage treatment method of flowing drainage into an adjustment tank, and sending water from the adjustment tank to a drainage treatment facility, wherein a water quality item or an operation management item related to a drainage load is continuously or periodically measured, a drainage load to a drainage inflow portion of the drainage treatment facility, which is a drainage treatment inflow portion, is estimated based on a measured value using a preset calculation formula, when the estimated drainage load is less than a prescribed threshold value, the drainage is supplied to the adjustment tank, and when the estimated drainage load is equal to or more than the threshold value, the drainage is branched at a drainage branching position on an upstream side of the adjustment tank and stored in a high-load adjustment tank.

2. The drainage treatment method according to claim 1, wherein the water quality item or the operation management item related to the drainage load includes a pollution load of the drainage or an item related to the pollution load, and a drainage flow rate flowing into the drainage treatment facility.

3. The drainage treatment method according to claim 1, wherein when the drainage load becomes equal to or less than a prescribed threshold value in a case where the drainage sent from the high-load adjustment tank is merged on a more downstream side than the drainage branching position, the drainage is sent from the high-load adjustment tank.

4. The drainage treatment method according to claim 3, wherein the drainage is sent from the high-load adjustment tank and merged on a downstream side of the adjustment tank.

5. The drainage treatment method according to claim 3, wherein the drainage is sent from the high-load adjustment tank to the adjustment tank. ​ ​ ​ ​ ​ ​ ​

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