Methods for estimating wastewater load and wastewater treatment

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

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

[0004] Furthermore, in physicochemical treatments 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] In the past, operators would periodically collect and analyze wastewater to determine the wastewater load at the inlet 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, or reducing the amount of wastewater inflow to the wastewater treatment plant. However, this method was always done manually, making continuous measurement impossible, and the inflow of high-load wastewater could be overlooked or measures delayed, leading to the breakdown of the wastewater treatment system and a deterioration in the quality of the treated water. Therefore, it is extremely important to continuously monitor the load of inflowing wastewater and take prompt measures to prevent the wastewater treatment system from breaking down.

[0006] In Patent Document 1, COD (Chemical Oxygen Discharge) is removed near the entrance of the biological treatment system. The wastewater load at the inlet of the wastewater treatment plant is evaluated by measuring TOC (Total Organic Carbon Demand) or TOC (Total Organic Carbon) and flow rate. However, when measuring near the inlet of the biological treatment plant, there is an issue with stable measurement due to slime adhesion to the measuring instrument.

[0007] The conditions for slime formation are generally pH 4-9, water temperature 15-35°C, BOD (Biochemical Oxygen Discharge) It is known that the oxygen demand (Oxygen Demand) concentration in raw wastewater treatment plants is 30 mg / L or higher. Fluctuations in water quality are leveled out in a tank (hereafter referred to as an equalization tank) installed before the wastewater treatment plant, making the raw water prone to the aforementioned conditions favorable for the formation of slime, such as microorganisms. This tendency is particularly pronounced when the downstream wastewater treatment is biological treatment. Therefore, when measuring the wastewater in the equalization tank or downstream from the equalization tank with an instrument, there is a concern that slime will adhere to the instrument or the sampling pipe will become clogged, resulting in inaccurate measurements. In addition, when measuring in the equalization tank or downstream from the equalization tank, considering the time lag between the start of measurement and the result, even if the tank detects that the wastewater is overloaded, countermeasures may be delayed, or the tank may continue to operate at a high load in the downstream stages due to the already high load, or dilution may be required. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-138976 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 aims 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 slime from adhering to the meter, and a wastewater treatment method that can stably perform wastewater treatment. [Means for solving the problem]

[0010] After extensive research, the inventors discovered that when wastewater with a quality that can suppress slime generation, such as wastewater from acid or alkali cleaning or containing sterilizing ingredients such as oxidizers (e.g., 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 (e.g., more than 20% of the total wastewater inflow time), it is difficult for microorganisms to continue to grow and slime generation is suppressed. Therefore, when such fluctuations in wastewater quality occur, the risk of slime adhesion to the meter can be reduced and the above-mentioned objective can be achieved by measuring the wastewater with a wastewater contact-type meter upstream of the equalization tank rather than in the equalization tank or downstream of the equalization tank. Regarding such fluctuations in wastewater quality, for example, when the wastewater flows in from a single line, the water quality may fall into conditions that can suppress slime generation depending on the time of day, depending on the product lineup in the line and the cleaning process of the production line. When wastewater flows in from multiple systems, variations in water quality due to differences in the product lineup in a certain system or the cleaning process of the production line may cause the wastewater from that system to meet the slime-inhibiting water quality conditions depending on the time of day, and in addition, when wastewater from another system with a different water quality flows in, the inflow wastewater from that system or the mixed wastewater from multiple systems may meet the water quality conditions that can inhibit slime generation. The present invention is based on this finding.

[0011] [1] A method for estimating the wastewater load of 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 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 loads, in which water quality items or operational management items are measured or estimated using a wastewater contact-type meter upstream of the adjustment tank and, in the case of multiple systems, downstream of the confluence of the wastewater from each system, and the wastewater load is estimated based on the measured or estimated values.

[0012] [2] The water quality capable of suppressing slime generation is a water temperature of 40°C or higher, a pH of 4 or lower, a pH of 9 or higher, and an ORP of 750 mV or higher. [1] The method for estimating wastewater load described in [1].

[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, measuring a first flow rate of wastewater flowing into the adjustment tank; A method for estimating wastewater load according to [1] or [2], which estimates the pollution load or an item correlated with the pollution load at the wastewater inlet (wastewater treatment inlet) to the wastewater treatment facility using the measured pollution load or an item correlated with the pollution load and the first flow rate.

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

[0015] [5] A wastewater treatment method, in which, when the wastewater load estimated by the method described in [4] is equal to or greater than a predetermined value, the destination of the wastewater flowing into the adjustment tank is switched from the adjustment tank to a high-load adjustment tank.

[0016] [6] A wastewater treatment method according to [5], wherein, after switching the destination of the wastewater from the adjustment tank to the high-load adjustment tank, if the estimated wastewater load falls below a predetermined value, the wastewater in the high-load adjustment tank is sent to the wastewater treatment equipment.

[0017] [7] A wastewater treatment method according to [5], in which, after switching the destination of the wastewater from the adjustment tank to the high-load adjustment tank, if the 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 according to [5], wherein the equalization tank into which the wastewater flows is arranged in parallel and in multiple stages, and the water is sent from the equalization tank to the wastewater treatment equipment at a flow rate such that the estimated wastewater load does not exceed a predetermined value. [Effects of the Invention]

[0019] According to the present invention, water quality items or operational management items such as the pollution load of wastewater or items correlated with the pollution load can be stably measured while preventing slime from adhering to the meter. Furthermore, according to the present invention, wastewater treatment can be stably performed. [Brief explanation 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. [Figure 2] FIG. 2 is a schematic configuration diagram of the wastewater treatment system according to the embodiment. [Figure 3] FIG. 2 is a schematic configuration diagram of the wastewater treatment system according to the embodiment. [Figure 4] FIG. 2 is a schematic configuration diagram of the wastewater treatment system according to the embodiment. [Figure 5] FIG. 2 is a schematic configuration diagram of the wastewater treatment system according to the embodiment. [Figure 6] FIG. 2 is a schematic configuration diagram of the wastewater treatment system according to the embodiment. [Figure 7] FIG. 2 is a schematic configuration diagram of the wastewater treatment system according to the embodiment. [Figure 8] FIG. 2 is a schematic configuration diagram of the wastewater treatment system according to the embodiment. [Figure 9] FIG. 2 is a schematic configuration diagram of the wastewater treatment system according to the embodiment. [Figure 10] FIG. 2 is a schematic configuration diagram of the wastewater treatment system according to the embodiment. [Figure 11] FIG. 2 is a schematic configuration diagram of the wastewater treatment system according to the embodiment. [Figure 12] FIG. 2 is a schematic configuration diagram of the wastewater treatment system according to the embodiment. [Figure 13] FIG. 2 is a schematic configuration diagram of the wastewater treatment system according to the embodiment. [Figure 14] FIG. 2 is a schematic configuration diagram of the wastewater treatment system according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[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 downstream of the adjustment tank 1, a pollution load measuring unit 4 installed upstream of the adjustment tank 1, 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 meets 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 (oxidation-reduction potential) of 750mV 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 at relatively short time intervals or continuously. 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 other indicators of pollution load such as COD concentration and SS may also be used. 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 unit 4 measures the pollution load (TOC concentration) by immersing an instrument in the wastewater upstream of the adjustment tank 1, and downstream of the junction of the wastewater from each system in the case of multiple systems.

[0025] One or more equalization tanks 1 are provided, and as described below, multiple equalization tanks 1 may be arranged in parallel. There are no particular restrictions on the specifications of the equalization tank 1, such as its volume. The equalization tank 1 is defined as having an HRT (hydraulic retention time) of 30 minutes or more, with the aim 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 equalizing tank 1 may be a flow meter, or if the equalizing tank 1 is a batch-flow tank, it may be calculated from the increase in water level per unit time in the equalizing tank 1. Alternatively, if the equalizing tank 1 is a continuous-flow tank, the flow rate of wastewater flowing into the equalizing tank 1 may be calculated from the sum of the change in the storage volume of the equalizing tank 1 and the discharge flow rate from the equalizing tank.

[0027] The wastewater treatment facility 3 removes dirt, oil, and other contaminants 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 wastewater flowing into the wastewater treatment equipment 3, may be a flow meter, or, if the adjustment tank 1 is a batch water supply tank, may be calculated from the amount of decrease in water level 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 a batch water supply, for example, different estimation methods can be used, as follows:

[0031] <When water is continuously flowing> Estimation method (1)-1 The TOC concentration (mg / L) at the inlet of the wastewater treatment plant 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 50 minutes ago can be considered to be the TOC concentration at the inlet of the wastewater treatment plant (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 complete 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 has 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 time the inlet valve is "open" to "closed" or while the pump is running. If it is difficult to obtain the valve open / close signal or the pump start / stop signal, it is also possible to determine the timing at which wastewater is flowing into the equalization tank 1 from changes in the water level.

[0034] The calculation unit 6 estimates the wastewater load (kg-TOC / day) using the following equation 1 from 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 rate measurement unit 10.

[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 Figure 2, when an equalization tank 2 is installed in series with the equalization tank 1 between the equalization tank 1 and the wastewater treatment equipment 3, the TOC concentration (estimated value A) at the outlet of the equalization tank 1 is first estimated. One or more equalization tanks 2 may be installed, and as described below, multiple equalization tanks 2 may be arranged in parallel. The specifications of the equalization tank 2, such as its volume, are not particularly limited. As in Figure 1, the estimation method differs depending on whether the equalization tank 1 is a continuous or batch-flow system. In the case of continuous flow, the TOC concentration (estimated value A) at the outlet of the equalization tank 1 is estimated using the above-mentioned estimation method (1)-1 or (2)-1, and in the case of batch-flow, the TOC concentration is estimated using estimation method (3)-1.

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

[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 equalization tank 2.

[0039] Estimation method (2)-2 From the TOC concentration (estimated value A) and the flow rate flowing into equalization tank 2, the change in the wastewater concentration flowing into equalization tank 2 is estimated using a perfect mixing tank model, 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 calculated by dividing the total water volume (m 3 ) to estimate the TOC concentration (mg / L) at the inlet of the wastewater treatment plant.

[0041] The third flow rate measuring unit 8, which measures the flow rate of wastewater flowing into the equalizing tank 2, may be a flow meter, or, if the equalizing tank 2 is a batch-flow type, may be calculated from the increase in water level per unit time in the equalizing tank 2. Alternatively, if the equalizing tank 2 is a continuous-flow type, the flow rate of wastewater flowing into the equalizing tank 2 may be calculated from the sum of the change in the storage volume of the equalizing tank 2 and the discharge flow rate from the equalizing 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 rate measuring unit 10.

[0043] Next, as shown in Figure 3, consider the case where equalization tanks 2A and 2B are installed 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 of equalization tank 1 flows into equalization tank 2A ​​or 2B. Wastewater flowing out of equalization tank 2A ​​flows into wastewater treatment equipment 3. Wastewater flowing out of 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 with a flow meter or calculated from the amount of increase in 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 with a flow meter or calculated from the amount of decrease in 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 tanks or batch water supply tanks. One or more adjustment tanks 2A may be provided, and multiple 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 calculated by dividing the total water volume (m 3 ) to estimate the TOC concentration (mg / L) in the 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 Using 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, the change in the wastewater concentration flowing into equalization tank 1 is estimated using a perfect mixing tank model, 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 was 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 equalization tank 2A) is estimated from the TOC concentration (estimated value D) at the outlet of the equalization tank 1 obtained as described above and the flow rate into the equalization tank 2A. If the equalization tank 2A ​​is a continuous water supply, the TOC concentration (estimated value E) at the wastewater treatment inlet is estimated using estimation method (1)-3 or (2)-4, and if the equalization tank 2A ​​is a batch water supply, the TOC concentration (estimated value E) at the wastewater treatment inlet is estimated using estimation method (1)-3 or (2)-4.

[0052] Estimation method (1)-3 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 D) over a period close to the residence time in the equalization tank 2A.

[0053] Estimation method (2)-4 From the TOC concentration (estimated value D) and the flow rate flowing into the equalization tank 2A, the change in the wastewater concentration flowing into the equalization tank 2A ​​is estimated using a perfect mixing tank model, 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 rate measuring 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, allowing for stable and accurate measurement of the pollution load. Furthermore, the wastewater load at the wastewater treatment inlet can be estimated from the measured pollution load and flow rate, and this estimated value can be used to quickly detect the inflow of high-load wastewater. Based on the estimated wastewater load, the amount of inflow to the wastewater treatment can be controlled or high-load wastewater can be distributed to the high-load adjustment tank to prevent the wastewater treatment from failing, 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 plant by 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 plant using the estimated TOC concentration and the flow rate measured by the second flow rate measurement unit 10, and determines whether or not it is acceptable for the wastewater to flow into the wastewater treatment facility 3.

[0059] If the calculation unit 6 determines that the wastewater load is high and that the wastewater treatment may fail, it closes valve 17A and opens 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 inlet and the wastewater load.

[0060] Thereafter, when the estimated wastewater load becomes low, the 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 opening and closing timing of valves 17A and 17B on a monitor screen or the like, and an operator may manually control the opening and closing of valves 17A and 17B in accordance with the display. Similarly, the calculation unit 6 may display the water supply timing of transfer pumps 19 and 20 on a monitor screen or the like so that the operator can see the timing, and an operator may manually operate the pumps in accordance with the display. Also, instead of transfer pumps 19 and 20, a transfer pump may be installed downstream of the confluence, and a switching valve may be provided just before the wastewater from adjustment tank 1 and the high-load adjustment tank confluence, allowing operation with a single 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 also be sent to the adjustment tank 1.

[0063] In the configuration shown in Figure 6, wastewater is sent to the adjusting tank 1 and adjusting tank 1' at will without taking into consideration the pollution load of the wastewater. 1 When sending wastewater to the valve 17 Open valve A 17 B is closed, and the adjusting tank1 When sending wastewater to the valve 17 Close valve A. 17 B is open. 1 and 1 Of the two equalization tanks, the one into which wastewater is not flowing is the one from which wastewater is sent to the wastewater treatment facility 3. When the calculation unit 6 determines that the wastewater load is high and that the wastewater treatment may fail, it controls the transfer pumps 19' and 20' to adjust the flow rate of the wastewater sent from the equalization tank 1 and the equalization tank 1' so that the wastewater load (TOC concentration x flow rate) is such that the wastewater treatment will not fail. The calculation unit 6 may display on a monitor screen or the like so that the amount of water sent by the transfer pumps 19' and 20' can be seen, and an operator may manually operate the pump according to the display. Alternatively, a transfer pump may be installed downstream of the confluence instead of the transfer pumps 19' and 20', and the amount of water sent from the equalization tanks 1 and 1' may be adjusted. Adjustment tank 1´ By providing a switching valve just before the drainage water from each of the two facilities joins, it is possible to operate the facility with one transfer pump.

[0064] Figure 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 Figure 2. By controlling the opening and closing of valves 7A and 7B, it is possible to switch whether the 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 using 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 equalization tank 2) by one of the above estimation methods (1)-2, (2)-2, or (3)-2, using the estimated TOC concentration at the outlet of the equalization tank 1 and the flow rate of wastewater flowing into the equalization tank 2 measured by the third flow rate measurement unit 8. In addition, the calculation unit 6 estimates the wastewater load at the wastewater treatment inlet by the above equation 1 from the estimated TOC concentration at the outlet of the equalization tank 1 and the flow rate of wastewater flowing into the equalization tank 2 measured by the second flow rate measurement unit 10.

[0067] If 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 valve 7A and opens valve 7B, causing the wastewater sent from adjustment tank 1 to flow into high-load adjustment tank 12. Even after the wastewater inflow destination is switched to high-load adjustment tank 12, the wastewater continues to be sent from adjustment tank 2 to wastewater treatment equipment 3 by transfer pump 20, and the calculation unit 6 continues to estimate the TOC concentration at the outlet of adjustment tank 1, the TOC concentration at the wastewater treatment inlet, and the wastewater load.

[0068] Thereafter, when the estimated wastewater load decreases (when 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 delivered from adjustment tank 1, but as shown in Fig. 8, a transfer pump 18A that delivers water from adjustment tank 1 to adjustment tank 2 and a transfer pump 18B that delivers 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 the wastewater is delivered to 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 timing can be seen, and an operator may manually operate the pumps 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, but 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 sent from adjustment tank 1, but as shown in Figure 10, 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 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 sent to the adjusting tank 2 and the adjusting tank 2' at will without considering the pollution load of the wastewater. When sending wastewater to the adjusting tank 2, the valve 7A is opened and the valve 7B is closed, and when sending wastewater to the adjusting 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 adjusting tank 2 or the adjusting tank 2' into which the wastewater has not flowed. Alternatively, as shown in Fig. 12, a transfer pump 18A that sends water from the adjusting tank 1 to the adjusting tank 2 and a transfer pump 18B that sends water from the adjusting tank 1 to the adjusting tank 2 are connected. 1 A transfer pump 18B may be provided to transfer water from the adjustment tank 2 to the adjustment tank 2', and the pumps may be started and stopped separately. When the calculation unit 6 determines that the wastewater load is high and that the wastewater treatment may fail, it controls the transfer pumps 19' and 20' to adjust the flow rate of the wastewater transferred from the adjustment tank 2 and the adjustment tank 2' so that the wastewater load (TOC concentration x flow rate) does not fail the wastewater treatment.

[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 the wastewater conveyed from adjustment tank 1 flows into adjustment tank 2 or high-load adjustment tank 12.

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

[0075] The calculation unit 6 uses the estimated TOC concentration of the high-load adjustment tank 12, the flow rate measured by the fifth flow rate measurement unit 15, the TOC concentration measured by the pollution load measurement unit 4, and the flow rate measured by the first flow rate measurement unit 5 to estimate the TOC concentration at the outlet of the adjustment tank 1 using 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 rate measurement unit 8 to estimate the TOC concentration at the wastewater treatment inlet (outlet of the adjustment tank 2) using one 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 wastewater treatment inlet and the flow rate at the wastewater treatment inlet measured by the second flow rate measurement unit 10 using the above formula 1.

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

[0079] Thereafter, when the drainage load decreases, 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 water 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 sent from adjustment tank 1, but as shown in Figure 14, 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 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 plant and estimating the wastewater load at the inlet of the wastewater treatment plant, but the calculation unit 6 may be configured as a single computer, or may be configured as a distributed processing unit using multiple computers.

[0082] The present invention is not limited to the above-described embodiments, and the components can be modified and embodied in practice without departing from the spirit of the invention. Furthermore, various inventions can be created by appropriately combining multiple components disclosed in the above-described embodiments. For example, some components may be omitted from all the components shown in the embodiments. Furthermore, components from different embodiments may be appropriately combined. [Explanation of symbols]

[0083] 1,2,2´ Adjustment tank 3 Wastewater treatment facilities 4. Pollution Load Measurement Section 5 1st flow rate measuring section 6 Arithmetic section 8 Third flow measurement section 10 2nd flow measurement 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 in a wastewater treatment facility in which wastewater from a single system or multiple systems flows into an equalizing tank and wastewater is transported from the equalizing tank, comprising: 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 a wastewater load, comprising: measuring water quality items with a wastewater contact-type meter upstream of the adjustment tank and, in the case of multiple systems, downstream of the confluence of wastewater from each system; measuring or estimating a first flow rate of wastewater flowing into the adjustment tank and a second flow rate of wastewater flowing into the wastewater treatment equipment; and estimating a wastewater load based on the measured values ​​of the water quality items and the measured or estimated values ​​of the first flow rate and second flow rate.

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 item measured by the wastewater contact-type meter is a pollution load or an item correlated with a pollution load, and the pollution load is any one of a TOC concentration, a COD concentration, and a SS concentration; measuring a first flow rate of wastewater flowing into the adjustment tank; 3. A method for estimating a wastewater load according to claim 1 or 2, wherein the measured pollution load or an item correlated with the pollution load and the first flow rate are used to estimate the pollution load or an item correlated with the pollution load at the wastewater inlet (wastewater treatment inlet) to the wastewater treatment equipment.

4. measuring a second flow rate of wastewater flowing into the wastewater treatment facility; The method for estimating a wastewater load according to claim 3 , wherein the wastewater load at the wastewater treatment inlet is estimated 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: switching a destination of wastewater flowing into said adjustment tank from said adjustment tank to a high-load adjustment tank when the wastewater load estimated by the method of claim 4 is equal to or greater than a predetermined value.

6. 6. The wastewater treatment method according to claim 5, wherein, 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 wastewater treatment equipment.

7. 6. The wastewater treatment method according to claim 5, wherein, 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.

8. 6. The wastewater treatment method according to claim 5, wherein the equalizing tanks into which the wastewater flows are arranged in parallel in multiple stages, and the water is conveyed from the equalizing 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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