Estimation method of wastewater load and wastewater treatment method

Abstract

To provide an estimation method of a wastewater load capable of stably measuring a water quality item or an operation control item of wastewater while preventing adhesion of a slime to a wastewater contact type instrument and a wastewater treatment method capable of stably conducting a wastewater treatment.SOLUTION: A method estimates a wastewater load at a wastewater treatment facility with a regulation tank into which wastewater from a single system or plural systems flows and out of which the wastewater is discharged. A water quality item or an operation control item is measured or estimated by a wastewater contact side instrument at a side upstream of the regulation tank and a side downstream of a merging part of wastewater from respective systems in the plural systems, and estimates a wastewater load according to a measured value or an estimated value.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for estimating the wastewater load at the inlet of a wastewater treatment plant by continuously or periodically measuring the pollution load of wastewater or an item correlated with the pollution load upstream of an adjustment tank, and a wastewater treatment method for stabilizing the wastewater treatment plant by adjusting the inflow rate to the wastewater treatment plant or allocating high-load wastewater based on the estimated wastewater load. [Background technology]

[0002] Wastewater discharged from beverage, food, and other manufacturing plants often varies greatly in concentration and volume depending on the product and production volume, the elapsed time for cleaning the production line, etc. The optimal operating conditions for wastewater treatment often differ depending on the wastewater load, and large fluctuations in the wastewater load can affect the treatment status.

[0003] In particular, organic wastewater is generally treated by biological treatment such as aerobic or anaerobic treatment. However, if the wastewater load is large, the biological treatment may fail due to the organisms exceeding their processing capacity, resulting in problems such as a deterioration in the quality of the treated water.

[0004] In addition, in physicochemical processes such as the Fenton reaction and adsorption, the amount of chemicals or adsorbents required to be added changes, so it is important to understand the fluctuations in the load of wastewater flowing into the treatment facility.

[0005] Conventionally, operators would periodically collect and analyze wastewater to grasp the wastewater load at the inflow point of the wastewater treatment plant, and when high-load wastewater flowed in, they would manually take measures such as emergency evacuation to another tank, dilution, and reducing the amount of inflow to the wastewater treatment plant. However, this method does not allow continuous measurement because it is always done manually, and if the inflow of high-load wastewater is overlooked or measures are delayed, the wastewater treatment plant may break down and the quality of the treated water may deteriorate. Therefore, it is very important to continuously grasp the load of inflowing wastewater and take measures as soon as possible to prevent the wastewater treatment plant from breaking down.

[0006] In Patent Document 1, COD (Chemical Oxygen Demand) is measured near the inlet of the biological treatment plant. The wastewater load at the inlet of the wastewater treatment plant is evaluated by measuring total organic carbon (TOC) or total organic carbon (TOC) and flow rate. However, there is an issue with stable measurement near the inlet of the biological treatment plant due to the adhesion of slime to the measuring instrument.

[0007] The conditions for slime to form are generally pH 4-9, water temperature 15-35°C, and BOD (Biochemical Oxidation). It is known that the oxygen demand (OD) concentration is 30 mg / L or more. The raw water for wastewater treatment is easily subjected to the above conditions where slime such as microorganisms is easily generated because the water quality fluctuation is leveled in the water tank (hereinafter referred to as the adjustment tank) installed before the wastewater treatment. This tendency is particularly noticeable when the wastewater treatment in the latter stage is biological treatment, so when measuring the wastewater in the adjustment tank or the stage after the adjustment tank with an instrument, there is a concern that the measurement will not be accurate due to the adhesion of slime to the instrument or the clogging of the sampling tube. In addition, when measuring in the adjustment tank or the stage after the adjustment tank, considering the time lag from when the measurement is started to when the result is obtained, even if it is detected that the tank has become a high-load wastewater, countermeasures may be delayed, the high-load operation in the later stages will continue because the load in the tank is already high, and dilution may be required. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2013-138976 A Summary of the Invention [Problem to be solved by the invention]

[0009] The present invention has been made in consideration of the above-mentioned conventional situation, and has an object to provide a method for estimating wastewater load that can stably measure the pollution load of wastewater or items correlated with the pollution load while preventing the adhesion of slime to an instrument, and a wastewater treatment method that can stably perform wastewater treatment. [Means for solving the problem]

[0010] As a result of intensive research, the present inventors have found that when wastewater from acid / alkali cleaning, wastewater containing a bactericidal component such as an oxidizing agent, or other water quality capable of suppressing slime generation (for example, water temperature 40°C or higher, pH 4 or lower, pH 9 or higher, or ORP 750mV or higher) flows in for a certain period of time or more (for example, more than 20% of the total time the wastewater flows in), microorganisms are not able to grow continuously and slime generation is suppressed, so that when there is such a change in the wastewater quality, the risk of slime adhesion to the meter can be suppressed and the above-mentioned object can be achieved by measuring the wastewater with a wastewater contact type meter upstream of the adjustment tank, rather than in the adjustment tank or downstream of the adjustment tank. Regarding the change in the wastewater quality, for example, when the wastewater flows in from a single line, the water quality may fall within the conditions for suppressing slime generation depending on the time of day, depending on the difference in the product manufactured in the line or the cleaning process of the production line. When wastewater flows in from multiple lines, due to differences in the product types in a line or fluctuations in water quality due to the cleaning process of the production line, the wastewater from that line may fall within the slime-inhibiting water quality conditions depending on the time of day, and in addition, when wastewater from another line with a different water quality flows in, the inflow wastewater from that line or the mixed wastewater from multiple lines may fall within the water quality conditions that can inhibit slime generation. The present invention is based on such findings.

[0011] [1] A method for estimating a wastewater load in a wastewater treatment facility in which wastewater from a single system or multiple systems flows into an equalizing tank and wastewater is pumped from the equalizing tank, comprising the steps of: The wastewater flowing into the adjustment tank has a water quality that can suppress slime generation for at least a certain period of time, A method for estimating wastewater load, comprising measuring or estimating water quality items or operational management items using a wastewater contact-type instrument upstream of the adjustment tank and, in the case of multiple systems, downstream of the confluence of the wastewater from each system, and estimating the wastewater load based on the measured or estimated values.

[0012] [2] The water quality capable of suppressing slime generation is a method for estimating wastewater load described in [1], which satisfies at least one of the following conditions: water temperature of 40°C or higher, pH of 4 or lower, pH of 9 or higher, and ORP of 750 mV or higher.

[0013] [3] The water quality items or operational management items measured by the wastewater contact-type meter are pollution loads or items correlated with pollution loads, Measure a first flow rate of wastewater flowing into the adjustment tank; A method for estimating wastewater load described in [1] or [2], in which the measured pollution load or items correlated with the pollution load and the first flow rate are used to estimate the pollution load or items correlated with the pollution load at the wastewater inlet (wastewater treatment inlet) to the wastewater treatment equipment.

[0014] [4] Measure a second flow rate of wastewater flowing into the wastewater treatment facility; The method for estimating wastewater load according to [3], further comprising estimating the wastewater load at the inlet of the wastewater treatment treatment plant using the estimated pollution load at the inlet of the wastewater treatment plant or an item correlated with the pollution load and the second flow rate.

[0015] [5] A wastewater treatment method, comprising: when the wastewater load estimated by the method according to [4] is equal to or greater than a predetermined value, switching the inflow destination of wastewater into the adjustment tank from the adjustment tank to a high-load adjustment tank.

[0016] [6] A wastewater treatment method as described in [5], in which, after the inflow destination of the wastewater is switched from the adjustment tank to the high-load adjustment tank, if an estimated wastewater load becomes less than a predetermined value, the wastewater in the high-load adjustment tank is sent to the wastewater treatment equipment.

[0017] [7] A wastewater treatment method as described in [5], in which, after switching the inflow destination of the wastewater from the adjustment tank to the high-load adjustment tank, if an estimated wastewater load becomes less than a predetermined value, the wastewater in the high-load adjustment tank is sent to the adjustment tank.

[0018] [8] A wastewater treatment method as described in [5], in which the equalization tanks into which the wastewater flows are arranged in parallel in multiple stages, and water is conveyed from the equalization tanks to the wastewater treatment equipment at a flow rate such that an estimated wastewater load does not exceed a predetermined value. Effect of the Invention

[0019] According to the present invention, water quality items or operation management items such as the pollution load of wastewater or items correlated with the pollution load can be stably measured while preventing the adhesion of slime to the meter. In addition, according to the present invention, wastewater treatment can be stably performed. [Brief description of the drawings]

[0020] [Figure 1] 1 is a schematic configuration diagram of a wastewater treatment system according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic configuration diagram of a wastewater treatment system according to the embodiment. [Diagram 3] FIG. 2 is a schematic configuration diagram of a wastewater treatment system according to the embodiment. [Figure 4] FIG. 2 is a schematic configuration diagram of a wastewater treatment system according to the embodiment. [Diagram 5] FIG. 2 is a schematic configuration diagram of a wastewater treatment system according to the embodiment. [Figure 6] FIG. 2 is a schematic configuration diagram of a wastewater treatment system according to the embodiment. [Figure 7] FIG. 2 is a schematic configuration diagram of a wastewater treatment system according to the embodiment. [Figure 8] FIG. 2 is a schematic configuration diagram of a wastewater treatment system according to the embodiment. [Figure 9] FIG. 2 is a schematic configuration diagram of a wastewater treatment system according to the embodiment. [Figure 10] FIG. 2 is a schematic configuration diagram of a wastewater treatment system according to the embodiment. [Figure 11] FIG. 2 is a schematic configuration diagram of a wastewater treatment system according to the embodiment. [Figure 12] FIG. 2 is a schematic configuration diagram of a wastewater treatment system according to the embodiment. [Figure 13] FIG. 2 is a schematic configuration diagram of a wastewater treatment system according to the embodiment. [Figure 14] FIG. 2 is a schematic configuration diagram of a wastewater treatment system according to the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. As shown in Fig. 1, a wastewater treatment system according to an embodiment of the present invention includes an adjustment tank 1, a wastewater treatment facility 3 installed after the adjustment tank 1 (downstream side), a pollution load measuring unit 4 installed before the adjustment tank 1 (upstream side), a first flow rate measuring unit 5 that measures the flow rate of wastewater flowing into the adjustment tank 1, a second flow rate measuring unit 10 that measures the flow rate of wastewater flowing into the wastewater treatment facility 3, and a calculation unit 6 that estimates the wastewater load at the inlet of the wastewater treatment facility 3 (the outlet of the adjustment tank 1). The calculation unit 6 is, for example, a computer.

[0022] Wastewater from a single line flows into the adjustment tank 1, or wastewater from multiple lines is combined and flows in simultaneously or at different times. The wastewater flowing into the adjustment tank 1 is wastewater from acid or alkali cleaning, contains sterilizing components such as oxidizing agents, and has a water quality that can suppress slime generation (for example, water quality that satisfies at least one of the following conditions: water temperature 40°C or higher, pH 4 or lower, pH 9 or higher, and ORP (oxidation-reduction potential) 750 mV or higher) for a certain period of time or more (for example, accounting for more than 20% of the total wastewater inflow time).

[0023] The pollution load measuring unit 4 measures the pollution load of the wastewater flowing into the adjustment tank 1 periodically or continuously at relatively short time intervals. In this embodiment, an example in which TOC concentration is measured as the pollution load will be described, but the measurement item is not limited to TOC concentration, and may be other indicators of pollution load such as COD concentration or SS. The pollution load to be measured also includes items correlated with the pollution load, such as electrical conductivity and Brix sugar content.

[0024] The pollution load measuring section 4 is located upstream of the adjustment tank 1, and in the case of multiple systems, downstream of the confluence of the wastewater from each system, and measures the pollution load (TOC concentration) by immersing an instrument in the wastewater.

[0025] One or more adjustment tanks 1 are provided, and as described below, multiple adjustment tanks 1 may be arranged in parallel. The specifications of the adjustment tank 1, such as its volume, are not particularly limited. The adjustment tank 1 is defined as having an HRT (hydraulic retention time) of 30 minutes or more for the purpose of adjusting and mitigating fluctuations in water quality and water volume.

[0026] The first flow rate measuring unit 5 that measures the flow rate of wastewater flowing into the adjustment tank 1 may be a flow meter, or, in the case where the adjustment tank 1 is a batch-flow tank, it may be calculated from the amount of increase in the water level per unit time in the adjustment tank 1. Alternatively, in the case where the adjustment tank 1 is a continuous flow tank, the flow rate of wastewater flowing into the adjustment tank 1 may be calculated from the sum of the change in the storage volume of the adjustment tank 1 and the discharge flow rate from the adjustment tank.

[0027] The wastewater treatment facility 3 removes dirt, oil, and the like from the wastewater. There are no particular limitations on the wastewater treatment method or number of systems. Treatment methods include, for example, so-called biological treatment, including aerobic and anaerobic treatment, and physicochemical treatment, such as Fenton treatment and activated carbon treatment.

[0028] The second flow rate measuring unit 10, which measures the flow rate of the wastewater flowing into the wastewater treatment equipment 3, may be a flow meter, or, in the case of batch water flow through the adjustment tank 1, may be one that calculates the flow rate from the amount of water level reduction per unit time in the adjustment tank 1.

[0029] The calculation unit 6 estimates the TOC concentration at the inlet (outlet of the adjustment tank 1) of the wastewater treatment facility 3, using the TOC concentration measured by the pollution load measurement unit 4 and the flow rate measured by the first flow rate measurement unit 5. The calculation unit 6 also estimates the wastewater load (kg-TOC / day) to be sent to the wastewater treatment facility 3, using the estimated TOC concentration and the flow rate measured by the second flow rate measurement unit 10.

[0030] The TOC concentration at the inlet of the wastewater treatment equipment 3 (hereinafter also referred to as the "wastewater treatment inlet") can be estimated using the TOC concentration measured by the pollution load measuring unit 4 and the flow rate measured by the first flow rate measuring unit 5 using various proposed concentration calculation models for retention tanks. However, depending on whether the adjustment tank 1 is a continuous water supply or batch water supply tank, different estimation methods can be used, as described below.

[0031] <When water is continuously flowing> Estimation method (1)-1 The TOC concentration (mg / L) at the inlet of the wastewater treatment process is estimated by taking a moving average of the TOC concentration measured upstream of the equalization tank 1 over a time period close to the residence time in the equalization tank 1. For example, if the residence time in the equalization tank 1 is 50 minutes, the average of the TOC concentration measurement results from the present to the previous 50 minutes can be regarded as the TOC concentration at the inlet of the wastewater treatment process (discharged from the equalization tank 1).

[0032] Estimation method (2)-1 From the TOC concentration and flow rate measured upstream of equalization tank 1, a perfect mixing tank model is used to estimate the change in wastewater concentration flowing into equalization tank 1, and the TOC concentration (mg / L) at the wastewater treatment inlet is estimated.

[0033] <When passing water through a batch> Estimation method (3)-1 The total TOC weight (g) flowing into the adjustment tank 1 is calculated by dividing the total water volume (m 3) to estimate the TOC concentration (mg / L) at the inlet of the wastewater treatment plant. In order to accurately grasp the total TOC weight and total water volume that have flowed into the equalization tank 1, it is desirable to obtain the equalization tank inlet valve open / close signal and the pump start / stop signal, and calculate the load by integrating the TOC concentration and water volume from the inlet valve "open" to "closed" or the time the pump is operating. If it is difficult to obtain the valve open / close signal or the pump start / stop signal, it is also possible to grasp the timing at which wastewater is flowing into the equalization tank 1 from the change in the water level in the equalization tank 1.

[0034] The calculation unit 6 estimates the wastewater load (kg-TOC / day) using the TOC concentration at the wastewater treatment inlet estimated by any of the above estimation methods (1)-1, (2)-1, or (3)-1 and the flow rate at the wastewater treatment inlet measured by the second flow measurement unit 10, using the following equation 1.

[0035] Equation 1: Wastewater load (kg-TOC / day) = TOC concentration at the inlet of the wastewater treatment plant (mg / L) × flow rate at the inlet of the wastewater treatment plant (m 3 / h)×24h / 1000

[0036] As shown in Fig. 2, when an adjustment tank 2 is provided in series with the adjustment tank 1 between the adjustment tank 1 and the wastewater treatment equipment 3, the TOC concentration (estimated value A) at the outlet of the adjustment tank 1 is estimated first. One or more adjustment tanks 2 are provided, and as described later, multiple adjustment tanks 2 may be arranged in parallel. The specifications of the adjustment tank 2, such as its volume, are not particularly limited. As in Fig. 1, the estimation method differs depending on whether the adjustment tank 1 is a continuous water supply or a batch water supply. In the case of continuous water supply, the above estimation method (1)-1 or (2)-1 is used to estimate the TOC concentration (estimated value A) at the outlet of the adjustment tank 1, and in the case of batch water supply, estimation method (3)-1 is used.

[0037] Next, the TOC concentration (estimated value B) at the wastewater treatment inlet (outlet of the adjustment tank 2) is estimated from the TOC concentration (estimated value A) at the outlet of the adjustment tank 1 obtained as described above and the flow rate of the wastewater flowing into the adjustment tank 2 measured by the third flow measurement unit 8. Again, the estimation method differs depending on whether the adjustment tank 2 is a continuous water supply or a batch water supply. In the case of continuous water supply, the following estimation method (1)-2 or (2)-2 is used to estimate the TOC concentration (estimated value B) at the wastewater treatment inlet. In the case of batch water supply, estimation method (3)-2 is used.

[0038] Estimation method (1)-2 The TOC concentration (mg / L) at the inlet of the wastewater treatment plant is estimated by taking a moving average of the TOC concentration (estimated value A) over a period close to the residence time in the adjustment tank 2.

[0039] Estimation method (2)-2 From the TOC concentration (estimated value A) and the flow rate flowing into equalization tank 2, a perfect mixing tank model is used to estimate the change in the wastewater concentration flowing into equalization tank 2, and the TOC concentration (mg / L) at the wastewater treatment inlet is estimated.

[0040] Estimation method (3)-2 The total TOC weight (g) flowing into the adjustment tank 2 is expressed as the total water volume (m 3 ) to estimate the TOC concentration (mg / L) at the wastewater treatment inlet.

[0041] The third flow rate measuring unit 8, which measures the flow rate of the wastewater flowing into the adjustment tank 2, may be a flow meter, or, in the case where the adjustment tank 2 is a batch-flow type, may be a unit that calculates the flow rate from the increase in the water level per unit time in the adjustment tank 2. Alternatively, in the case where the adjustment tank 2 is a continuous flow type, the flow rate of the wastewater flowing into the adjustment tank 2 may be calculated from the sum of the change in the storage volume of the adjustment tank 2 and the discharge flow rate from the adjustment tank.

[0042] The wastewater load (kg-TOC / day) is estimated using the above equation 1 from the TOC concentration (estimated value B) at the wastewater treatment inlet obtained in this manner and the flow rate at the wastewater treatment inlet measured by the second flow measurement unit 10.

[0043] Next, as shown in Fig. 3, let us consider a case in which equalization tanks 2A and 2B are provided in parallel between equalization tank 1 and wastewater treatment equipment 3, and wastewater is returned from equalization tank 2B to equalization tank 1. Wastewater flowing out from equalization tank 1 flows into equalization tank 2A ​​or 2B. Wastewater flowing out from equalization tank 2A ​​flows into wastewater treatment equipment 3. Wastewater flowing out from equalization tank 2B is returned to equalization tank 1.

[0044] The fourth flow rate measuring unit 13 measures the flow rate of wastewater flowing into the adjustment tank 2B, and may be measured by a flow meter or calculated from the amount of increase in the water level per unit time in the adjustment tank 2B. The fifth flow rate measuring unit 15 measures the flow rate of wastewater returned from the adjustment tank 2B to the adjustment tank 1, and may be measured by a flow meter or calculated from the amount of decrease in the water level per unit time in the adjustment tank 2B.

[0045] In this case, the condition is that the adjustment tank 2B, which returns wastewater to the adjustment tank 1, is a batch water supply tank, and the adjustment tank 1 and the adjustment tank 2A ​​may be either continuous water supply tank or batch water supply tank. One or more adjustment tanks 2A are provided, and a plurality of adjustment tanks 2A may be arranged in parallel.

[0046] First, the TOC concentration (estimated value C) of the wastewater in the adjustment tank 2B is estimated using the following estimation method (3)-3 from the TOC concentration measured upstream of the adjustment tank 1 and the flow rate measured by the fourth flow rate measurement unit 13.

[0047] Estimation method (3)-3 The total TOC weight (g) flowing into the adjustment tank 2B is expressed as the total water volume (m 3 ) to estimate the TOC concentration (mg / L) in equalization tank 2B.

[0048] Next, the TOC concentration at the outlet of the adjustment tank 1 (estimated value D) is estimated from the TOC concentration in the adjustment tank 2B obtained as described above (estimated value C), the flow rate measured by the fifth flow rate measurement unit 15, and the TOC concentration and flow rate measured upstream of the adjustment tank 1. When the adjustment tank 1 is a continuous water supply tank, the estimation is performed using estimation method (2)-3, and when the adjustment tank 1 is a batch water supply tank, the estimation is performed using estimation method (3)-4.

[0049] Estimation method (2)-3 From the TOC concentration and flow rate measured upstream of equalization tank 1, the TOC concentration in equalization tank 2B (estimated value C), and the flow rate flowing from equalization tank 2B to equalization tank 1, a perfect mixing tank model is used to estimate the change in wastewater concentration flowing into equalization tank 1, and the TOC concentration (mg / L) at the outlet of equalization tank 1 is estimated.

[0050] Estimation method (3)-4 The total TOC weight (g) flowing into the adjustment tank 1 is multiplied by the total water volume (m 3 ) to estimate the TOC concentration (mg / L) at the outlet of equalization tank 1. The total TOC weight and total water volume are calculated by adding the TOC weight and water volume measured upstream of equalization tank 1 to the TOC weight and water volume returned from equalization tank 2B, respectively.

[0051] Next, the TOC concentration (estimated value E) at the wastewater treatment inlet (outlet of the adjustment tank 2A) is estimated from the TOC concentration (estimated value D) at the outlet of the adjustment tank 1 obtained as described above and the flow rate into the adjustment tank 2A. If the adjustment tank 2A ​​is a continuous water supply system, the TOC concentration (estimated value E) at the wastewater treatment inlet is estimated using estimation method (1)-3 or (2)-4, and if it is a batch water supply system, estimation method (3)-5.

[0052] Estimation method (1)-3 The TOC concentration (estimated value D) is averaged over a period close to the residence time in the equalization tank 2A ​​to estimate the TOC concentration (mg / L) at the inlet of the wastewater treatment plant.

[0053] Estimation method (2)-4 From the TOC concentration (estimated value D) and the flow rate flowing into the equalization tank 2A, a perfect mixing tank model is used to estimate the change in the wastewater concentration flowing into the equalization tank 2A, and the TOC concentration (mg / L) at the wastewater treatment inlet is estimated.

[0054] Estimation method (3)-5 The total TOC weight (g) flowing into the adjustment tank 2A ​​is calculated by dividing the total water volume (m 3 ) to estimate the TOC concentration (mg / L) at the wastewater treatment inlet.

[0055] The wastewater load (kg-TOC / day) is estimated using the above equation 1 from the TOC concentration (estimated value E) at the wastewater treatment inlet obtained in this manner and the flow rate at the wastewater treatment inlet measured by the second flow measurement unit 10.

[0056] According to this embodiment, the pollution load (or items correlated with the pollution load) is measured upstream of the adjustment tank 1 where pH, water temperature, and water quality fluctuate greatly and slime is unlikely to occur, so the pollution load can be measured stably and accurately. In addition, the wastewater load at the inlet of the wastewater treatment is estimated from the measured pollution load and flow rate, and the inflow of high-load wastewater can be quickly detected from this estimated value. Based on the estimated wastewater load, the inflow amount to the wastewater treatment can be controlled or high-load wastewater can be distributed to the high-load adjustment tank so that the wastewater treatment does not break down, thereby stabilizing the wastewater treatment.

[0057] Fig. 4 shows a configuration in which a high-load adjustment tank 12 is provided in the wastewater treatment system shown in Fig. 1. In the configuration shown in Fig. 4, the high-load adjustment tank 12 is arranged in parallel with the adjustment tank 1. By controlling the opening and closing of valves 17A and 17B, it is possible to switch whether the wastewater delivered by the transfer pump 11 flows into the adjustment tank 1 or the high-load adjustment tank 12.

[0058] The calculation unit 6 acquires the TOC concentration measured by the pollution load measurement unit 4 and the flow rate measured by the first flow rate measurement unit 5, and estimates the TOC concentration at the inlet of the wastewater treatment by any one of the above estimation methods (1)-1, (2)-1, or (3)-1. The calculation unit 6 also estimates the wastewater load at the inlet of the wastewater treatment using the estimated TOC concentration and the flow rate measured by the second flow rate measurement unit 10, and determines whether it is acceptable for the wastewater to flow into the wastewater treatment facility 3.

[0059] When the calculation unit 6 determines that the wastewater treatment may fail due to a high wastewater load, it closes the valve 17A and opens the valve 17B to allow the wastewater to flow into the high-load adjustment tank 12. Even after the wastewater inflow destination is switched to the high-load adjustment tank 12, the transfer pump 20 continues to transport the wastewater from the adjustment tank 1 to the wastewater treatment equipment 3, and the calculation unit 6 continues to estimate the TOC concentration at the wastewater treatment inflow and the wastewater load.

[0060] Thereafter, when the estimated wastewater load becomes low, the inflow destination of the wastewater is switched from the high-load adjustment tank 12 to the adjustment tank 1. The calculation unit 6 also controls the transfer pump 19 to send the wastewater from the high-load adjustment tank 12 to the wastewater treatment equipment 3. The wastewater from the adjustment tank 1 is mixed with the wastewater from the high-load adjustment tank 12 and flows into the wastewater treatment equipment 3. It is preferable to control the transfer pump 19 to adjust the flow rate of the wastewater sent from the high-load adjustment tank 12 so as to prevent the wastewater treatment from failing.

[0061] The calculation unit 6 may display the timing of opening and closing the valves 17A and 17B on a monitor screen or the like, and an operator may manually control the opening and closing of the valves 17A and 17B according to the display. Similarly, the calculation unit 6 may display the timing of water supply from the transfer pumps 19 and 20 on a monitor screen or the like so that the operator can understand the timing, and the operator may manually operate the pumps according to the display. Also, instead of the transfer pumps 19 and 20, a transfer pump may be installed downstream of the confluence, and a switching valve may be provided before the confluence of the wastewater from the adjustment tank 1 and the high-load adjustment tank, so that operation can be performed with one transfer pump.

[0062] In the configuration shown in Figure 4, the wastewater in the high-load adjustment tank 12 is sent to the wastewater treatment equipment 3 when the wastewater load becomes low. However, as shown in Figure 5, the wastewater in the high-load adjustment tank 12 may be sent to the adjustment tank 1.

[0063] In the configuration shown in FIG. 6, wastewater is arbitrarily sent to the adjustment tank 1 and the adjustment tank 1' without considering the pollution load of the wastewater. When sending wastewater to the adjustment tank 2, the valve 7A is opened and the valve 7B is closed, and when sending wastewater to the adjustment tank 2', the valve 7A is closed and the valve 7B is opened. In addition, wastewater is sent to the wastewater treatment equipment 3 from the adjustment tank 2 or 2' into which wastewater does not flow. When the calculation unit 6 judges that the wastewater load is high and the wastewater treatment may fail, it controls the transfer pumps 19' and 20' and adjusts the flow rate of the wastewater sent from the adjustment tank 1 and the adjustment tank 1' so that the wastewater load (TOC concentration x flow rate) does not fail the wastewater treatment. The calculation unit 6 displays on a monitor screen or the like so that the amount of water sent by the transfer pumps 19' and 20' can be known, and an operator may manually operate the pump according to the display. In addition, instead of the transfer pumps 19', 20', a transfer pump may be installed downstream of the confluence, and a switching valve may be provided just before the wastewater from the adjustment tank 1 and the high-load adjustment tank 12 join, making it possible to operate the system with a single transfer pump.

[0064] Fig. 7 shows a configuration in which a high-load adjustment tank 12 is provided in parallel with the adjustment tank 2 of the wastewater treatment system shown in Fig. 2. By controlling the opening and closing of valves 7A and 7B, it is possible to switch whether wastewater conveyed from the adjustment tank 1 flows into the adjustment tank 2 or the high-load adjustment tank 12.

[0065] The calculation unit 6 acquires the TOC concentration measured by the pollution load measurement unit 4 and the flow rate measured by the first flow rate measurement unit 5, and estimates the TOC concentration at the outlet of the adjustment tank 1 by any one of the above estimation methods (1)-1, (2)-1, or (3)-1.

[0066] The calculation unit 6 estimates the TOC concentration at the wastewater treatment inlet (outlet of the adjustment tank 2) by any one of the above estimation methods (1)-2, (2)-2, or (3)-2 using the estimated TOC concentration at the outlet of the adjustment tank 1 and the flow rate of the wastewater flowing into the adjustment tank 2 measured by the third flow rate measuring unit 8. The calculation unit 6 also estimates the wastewater load at the wastewater treatment inlet by the above formula 1 from the estimated TOC concentration at the wastewater treatment inlet and the flow rate of the wastewater treatment inlet measured by the second flow rate measuring unit 10.

[0067] When the calculation unit 6 determines that the wastewater load is high (the wastewater load is equal to or greater than a predetermined value) and that the wastewater treatment may fail, it closes the valve 7A and opens the valve 7B to allow the wastewater sent from the adjustment tank 1 to flow into the high-load adjustment tank 12. Even after the wastewater inflow destination is switched to the high-load adjustment tank 12, the transfer pump 20 continues to send the wastewater from the adjustment tank 2 to the wastewater treatment equipment 3, and the calculation unit 6 continues to estimate the TOC concentration at the outlet of the adjustment tank 1, the TOC concentration at the wastewater treatment inflow, and the wastewater load.

[0068] Thereafter, when the estimated wastewater load becomes low (the wastewater load becomes less than a predetermined value), the destination of the wastewater is switched from the high-load adjustment tank 12 to the adjustment tank 2. The calculation unit 6 controls the transfer pump 19 to send the wastewater from the high-load adjustment tank 12 to the wastewater treatment equipment 3. The wastewater from the adjustment tank 2 is mixed with the wastewater from the high-load adjustment tank 12 and flows into the wastewater treatment equipment 3. It is preferable to control the transfer pump 19 to adjust the flow rate of the wastewater sent from the high-load adjustment tank 12 to the wastewater treatment equipment 3 so as to prevent the wastewater treatment from failing.

[0069] In the configuration of Fig. 7, the opening and closing of valves 7A and 7B was controlled to switch the inflow destination of wastewater sent from adjustment tank 1, but as shown in Fig. 8, a transfer pump 18A that sends water from adjustment tank 1 to adjustment tank 2 and a transfer pump 18B that sends water from adjustment tank 1 to high-load adjustment tank 12 may be provided, and the on / off of transfer pumps 18A and 18B may be controlled to switch whether wastewater is sent into adjustment tank 2 or high-load adjustment tank 12. The calculation unit 6 may display the on / off timing of transfer pumps 18A and 18B on a monitor screen or the like so that the operator can see it, and the pumps may be operated manually according to the display.

[0070] In the configuration shown in Figure 7, the wastewater in the high-load adjustment tank 12 is sent to the wastewater treatment equipment 3 when the wastewater load becomes low. However, as shown in Figure 9, the wastewater in the high-load adjustment tank 12 may also be sent to the adjustment tank 2.

[0071] In the configuration of Figure 9, the opening and closing of valves 7A and 7B was controlled to switch the destination of the wastewater pumped from adjustment tank 1, but as shown in Figure 10, a transfer pump 18A that pumps water from adjustment tank 1 to adjustment tank 2, and a transfer pump 18B that pumps water from adjustment tank 1 to high-load adjustment tank 12 may be provided, and the starting and stopping of transfer pumps 18A and 18B may be controlled to switch whether the wastewater from adjustment tank 1 flows into adjustment tank 2 or high-load adjustment tank 12.

[0072] In the configuration shown in FIG. 11, wastewater is arbitrarily sent to the adjustment tank 2 and the adjustment tank 2' without considering the pollution load of the wastewater. When sending wastewater to the adjustment tank 2, the valve 7A is opened and the valve 7B is closed, and when sending wastewater to the adjustment tank 2', the valve 7A is closed and the valve 7B is opened. In addition, the wastewater is sent to the wastewater treatment equipment 3 from the adjustment tank 2 or the adjustment tank 2' into which the wastewater does not flow. Alternatively, as shown in FIG. 12, a transfer pump 18A that sends water from the adjustment tank 1 to the adjustment tank 2 and a transfer pump 18B that sends water from the adjustment tank 2 to the adjustment tank 2' may be provided, and the pumps may be started and stopped separately. When the calculation unit 6 judges that the wastewater load is high and the wastewater treatment may fail, the calculation unit 6 controls the transfer pumps 19' and 20' to adjust the flow rate of the wastewater sent from the adjustment tank 2 and the adjustment tank 2' so that the wastewater load (TOC concentration x flow rate) is such that the wastewater treatment does not fail.

[0073] Fig. 13 shows a configuration in which the adjustment tanks 2A and 2B of the wastewater treatment system shown in Fig. 3 are replaced with an adjustment tank 2 and a high-load adjustment tank 12, respectively. By controlling the opening and closing of valves 7A and 7B, it is possible to switch whether wastewater conveyed from the adjustment tank 1 flows into the adjustment tank 2 or the high-load adjustment tank 12.

[0074] The calculation unit 6 acquires the TOC concentration measured by the pollution load measuring unit 4 and the flow rate of the wastewater flowing into the high-load adjustment tank 12 measured by the fourth flow rate measuring unit 13, and estimates the TOC concentration in the high-load adjustment tank 12 by the above-mentioned estimation method (3)-3.

[0075] The calculation unit 6 uses the estimated TOC concentration in the high-load adjustment tank 12, the flow rate measured by the fifth flow measurement unit 15, the TOC concentration measured by the pollution 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 above-mentioned estimation method (2)-3 or (3)-4.

[0076] Next, the calculation unit 6 uses the estimated TOC concentration at the outlet of the adjustment tank 1 and the flow rate of the wastewater flowing into the adjustment tank 2 measured by the third flow measurement unit 8 to estimate the TOC concentration at the wastewater treatment inlet (outlet of the adjustment tank 2) by any of the above estimation methods (1)-3, (2)-4, or (3)-5.

[0077] Then, the calculation unit 6 estimates the wastewater load from the estimated TOC concentration at the inlet of the wastewater treatment and the flow rate at the inlet of the wastewater treatment measured by the second flow rate measurement unit 10 using the above formula 1.

[0078] When the calculation unit 6 determines that the wastewater load is high and that the wastewater treatment may fail, it closes the valve 7A and opens the valve 7B to allow the wastewater sent from the adjustment tank 1 to flow into the high-load adjustment tank 12. Even after the wastewater inflow destination is switched to the high-load adjustment tank 12, the transfer pump 20 continues to send the wastewater from the adjustment tank 2 to the wastewater treatment equipment 3, and the calculation unit 6 continues to estimate the wastewater load.

[0079] Thereafter, when the drainage load becomes low, the drainage inflow destination is switched from the high-load adjustment tank 12 to the adjustment tank 2. The calculation unit 6 controls the transfer pump 19 to return the drainage from the high-load adjustment tank 12 to the adjustment tank 1.

[0080] In the configuration of Figure 13, the opening and closing of valves 7A and 7B was controlled to switch the destination of the wastewater pumped from adjustment tank 1, but as shown in Figure 14, a transfer pump 18A that pumps water from adjustment tank 1 to adjustment tank 2, and a transfer pump 18B that pumps water from adjustment tank 1 to high-load adjustment tank 12 may be provided, and the starting and stopping of transfer pumps 18A and 18B may be controlled to switch whether the wastewater from adjustment tank 1 flows into adjustment tank 2 or high-load adjustment tank 12.

[0081] In the above embodiment, a configuration was described in which the calculation unit 6 performs calculations such as estimating the pollution load at the inlet of the wastewater treatment process and estimating the wastewater load at the inlet of the wastewater treatment process. However, the calculation unit 6 may be configured as a single computer, or may perform distributed processing using multiple computers.

[0082] The present invention is not limited to the above-described embodiment, and the components can be modified and embodied in the implementation stage without departing from the gist of the invention. In addition, various inventions can be formed by appropriately combining the multiple components disclosed in the above-described embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, components from different embodiments may be appropriately combined. [Explanation of symbols]

[0083] 1,2,2´ Adjustment tank 3 Wastewater treatment facilities 4. Pollutant Load Measurement Section 5 1st flow rate measuring section 6 Arithmetic section 8 Third flow measurement section 10 2nd flow rate measuring section 11,19,19´,20,20´ Transfer pump 12 High load adjustment tank 13 4th flow measurement section 15 5th flow measurement section

Claims

1. A method for estimating a wastewater load of a wastewater treatment facility in which wastewater from a single line or multiple lines flows into an adjustment tank and wastewater is pumped from the adjustment tank, comprising the steps of: The wastewater flowing into the adjustment tank has a water quality that can suppress slime generation at least to a certain extent, A method for estimating wastewater load, comprising measuring or estimating water quality items or operational management items using a wastewater contact-type instrument upstream of the adjustment tank and, in the case of multiple systems, downstream of the confluence of the wastewater from each system, and estimating the wastewater load based on the measured or estimated values.

2. The method for estimating wastewater load according to claim 1, wherein the water quality capable of suppressing slime generation satisfies at least one of the following conditions: water temperature of 40°C or higher, pH of 4 or lower, pH of 9 or higher, and ORP of 750 mV or higher.

3. The water quality items or operational management items measured by the wastewater contact type meter are pollution loads or items correlated with pollution loads, Measure a first flow rate of wastewater flowing into the adjustment tank; The method for estimating a wastewater load according to claim 1 or 2, further comprising estimating a pollution load or an item correlated with the pollution load at a wastewater inlet (wastewater treatment inlet) to the wastewater treatment equipment using the measured pollution load or an item correlated with the pollution load and the first flow rate.

4. Measure a second flow rate of wastewater flowing into the wastewater treatment facility; The method for estimating a wastewater load at the wastewater treatment inlet according to claim 3 , further comprising estimating a wastewater load at the wastewater treatment inlet by using the estimated pollution load at the wastewater inlet or an item correlated with the pollution load and the second flow rate.

5. A wastewater treatment method, comprising the steps of: switching a destination of wastewater flowing into said adjustment tank from said adjustment tank to a high-load adjustment tank when a wastewater load estimated by the method according to claim 4 is equal to or greater than a predetermined value.

6. 6. The wastewater treatment method according to claim 5, wherein after the inflow destination of the wastewater is switched from the adjustment tank to the high-load adjustment tank, if an estimated wastewater load becomes less than a predetermined value, the wastewater in the high-load adjustment tank is sent to the wastewater treatment equipment.

7. 6. The wastewater treatment method according to claim 5, wherein after the inflow destination of the wastewater is switched from the adjustment tank to the high-load adjustment tank, when an estimated wastewater load becomes less than a predetermined value, the wastewater in the high-load adjustment tank is sent to the adjustment tank.

8. 6. The wastewater treatment method according to claim 5, wherein the adjustment tanks into which the wastewater flows are arranged in parallel in multiple stages, and the wastewater is conveyed from the adjustment tanks to the wastewater treatment facility at a flow rate such that an estimated wastewater load does not exceed a predetermined value.

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