Method for estimating drainage load and method for treating drainage

Abstract

The present invention provides a method for treating drainage by mixing drainage and thickened waste liquid and reducing industrial waste, and a method for accurately estimating a drainage load in a drainage inflow section of a drainage treatment facility that treats a mixture of drainage and thickened waste liquid. A drainage load in a drainage treatment inflow section of a drainage treatment facility that treats a mixture of drainage and thickened waste liquid after the mixture is combined is estimated. A first pollution load of the drainage is measured, a pollution load from the drainage at a specified position downstream of a point at which the drainage and the thickened waste liquid are combined is estimated based on the first pollution load, a second pollution load of the thickened waste liquid is measured, a pollution load of the thickened waste liquid at the specified position is estimated based on the second pollution load, and the drainage load is estimated based on the estimated value of the pollution load from the drainage at the specified position and the estimated value of the pollution load of the thickened waste liquid.

Description

Technical Field

[0001] The present invention relates to a method for estimating the drainage load of the drainage treatment inlet of a drainage treatment device, a drainage treatment method for stabilizing the drainage treatment by adjusting the inflow to the drainage treatment based on the estimated drainage load, and a method for reducing industrial waste. Background Technology

[0002] Wastewater discharged from beverage, food, and other manufacturing plants often varies significantly in concentration and volume depending on the type or quantity of products manufactured, the time elapsed during production line cleaning, and other factors. Suitable operating conditions for wastewater treatment also vary depending on the wastewater load, and large fluctuations in the wastewater load can sometimes impact the treatment process.

[0003] In particular, organic wastewater is generally treated as wastewater through aerobic or anaerobic biological treatment. However, if the wastewater load is large, it may exceed the biological treatment capacity, leading to biological treatment failure and deterioration of the treated water quality.

[0004] In addition, in physicochemical treatments such as Fenton reaction-based treatments or adsorption, the required amount of added reagents or adsorbents can vary, so it is important to understand the changes in the load of the wastewater flowing into the treatment equipment.

[0005] Previously, operators periodically collected and analyzed wastewater samples to determine the wastewater load at the inflow point for wastewater treatment. When high-load wastewater flowed in, they manually implemented emergency measures such as dilution to other tanks, reduction of the inflow to the wastewater treatment system, etc. However, this method, being entirely manual, lacked continuous measurement capabilities. Sometimes, missing high-load wastewater inflows or delaying countermeasures led to wastewater treatment failure and deterioration of treated water quality. Therefore, it is crucial to continuously monitor the inflow wastewater load and take timely countermeasures to prevent wastewater treatment failure.

[0006] Furthermore, it has been confirmed that high-volume waste liquids are not treated for drainage but are instead treated as industrial waste. For example, Patent Document 1 (Japanese Patent Application Publication No. 11-197664) describes the following: Generally, waste liquids with very high turbidity loads, such as plum brine processing liquid generated during plum processing, which may fail to be drained (hereinafter referred to as "concentrated waste liquid"), are disposed of as industrial waste. However, in methods of disposing of concentrated waste liquids as industrial waste, there are issues such as high costs for industrial waste treatment and environmental damage caused by carbon dioxide and other pollutants generated by industrial wastes, thus requiring a reduction in the amount of concentrated waste liquids treated for industrial waste.

[0007] Patent Document 2 (Japanese Patent Application Publication No. 2006-334491) describes a method for treating food waste into a form suitable for wastewater treatment without industrial waste treatment in order to reduce industrial waste volume. The method involves controlling the amount of food waste fed into a conventional wastewater treatment system based on a measured total organic carbon (TOC) concentration to prevent wastewater treatment failure. However, while Patent Document 2 explicitly describes measuring the TOC concentration in an adjustment tank after the food waste and the conventional wastewater treatment system are combined, and adjusting the amount of food waste fed into the system to bring the TOC concentration within a specified range, in cases where the TOC concentration in the conventional wastewater treatment system rises instantaneously, the measured value may exceed the specified range at the time of measurement.

[0008] Existing technical documents

[0009] Patent documents

[0010] Patent document 1: Japanese Patent Application Publication No. 11-197664.

[0011] Patent document 2: Japanese Patent Application Publication No. 2006-334491. Summary of the Invention

[0012] The problem that the invention aims to solve

[0013] The present invention was made in view of the above-mentioned actual situation, and its object is to provide a drainage treatment method that can reduce the amount of industrial waste by mixing concentrated waste liquid, which was previously disposed of as industrial waste, with drainage for drainage treatment, and a method for accurately estimating the drainage load in the drainage inlet of a drainage treatment device for treating the mixture of drainage and concentrated waste liquid.

[0014] Methods for solving problems

[0015] The drainage load estimation method based on the present invention is a method for estimating the drainage load in the drainage treatment inlet of a drainage treatment device that treats a mixture of drainage and concentrated waste liquid after merging. The method involves measuring a first turbidity load of the drainage, estimating the turbidity load from the drainage at the merging point of the drainage and concentrated waste liquid or at a predetermined location downstream of the merging point based on the first turbidity load, measuring a second turbidity load of the concentrated waste liquid, estimating the turbidity load of the concentrated waste liquid at the merging point or the predetermined location based on the second turbidity load, and estimating the drainage load based on the estimated values ​​of the turbidity load from the drainage at the merging point or the predetermined location and the estimated value of the turbidity load of the concentrated waste liquid.

[0016] In one embodiment of the invention, wastewater is conveyed to the wastewater treatment equipment via a regulating channel, the confluence point being located downstream of the regulating channel, and the first turbidity load being measured upstream of the regulating channel.

[0017] In one aspect of the invention, a first flow rate of the drainage flowing into the adjustment tank is measured, and the first turbidity load and the first flow rate are used to estimate the turbidity load of the drainage at the confluence point.

[0018] In one aspect of the invention, concentrated waste liquid is transported from a concentrated waste liquid tank to the confluence point, the second turbidity load is measured in the concentrated waste liquid tank, and the turbidity load of the concentrated waste liquid at the confluence point is estimated based on the second turbidity load.

[0019] The drainage treatment method of the present invention is a method of not transporting concentrated waste liquid to the confluence point when the drainage load estimated by the method is above a specified value.

[0020] In one aspect of the invention, if the estimated drainage load is less than a specified value, the concentrated waste liquid is transported to the confluence point at a flow rate not exceeding the specified value.

[0021] The effects of the invention

[0022] This invention enables the mixing of concentrated wastewater with wastewater for wastewater treatment, thereby reducing industrial waste volume. Furthermore, this invention allows for accurate estimation of the wastewater load in the wastewater inlet of a wastewater treatment system that treats a mixture of wastewater and concentrated wastewater. Attached Figure Description

[0023] Figure 1 This is a schematic structural diagram of the drainage treatment system according to the first embodiment of the present invention.

[0024] Figure 2 This is a schematic structural diagram of the drainage treatment system according to the second embodiment of the present invention.

[0025] Figure 3 This is a schematic structural diagram of the drainage treatment system according to the third embodiment of the present invention.

[0026] Figure 4 This is a schematic structural diagram of the drainage treatment system according to the fourth embodiment of the present invention.

[0027] Figure 5 This is a schematic structural diagram of the drainage treatment system according to the fifth embodiment of the present invention. Detailed Implementation

[0028] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0029] [First Implementation Method]

[0030] like Figure 1 As shown, the drainage treatment system of the first embodiment of the present invention includes: an adjusting tank 1; a drainage inflow pipe 23 connected to the upstream side of the adjusting tank 1 and transferring drainage to the adjusting tank 1; a first turbidity load measuring unit 4 for measuring the turbidity load of the drainage flowing into the adjusting tank 1 provided in the drainage inflow pipe 23; a first flow rate measuring unit 5 also provided in the drainage inflow pipe 23 for measuring the flow rate of the drainage flowing into the adjusting tank 1; a drainage discharge pipe 24 for allowing the drainage discharged from the adjusting tank 1 to flow into the drainage treatment system; a concentrated waste liquid tank 17 for storing concentrated waste liquid; a concentrated waste liquid inflow pipe 25 connected to the upstream side of the concentrated waste liquid tank 17 and transferring concentrated waste liquid to the concentrated waste liquid tank 17; and a second turbidity load measuring unit 18 provided in the concentrated waste liquid tank 17. The system includes a liquid tank 17 for measuring the turbidity load of concentrated waste liquid; a concentrated waste liquid discharge pipe 26 for merging the concentrated waste liquid discharged from the concentrated waste liquid tank 17 into a drainage discharge pipe 24; a second flow measurement unit 19, installed on the concentrated waste liquid discharge pipe 26, for measuring the flow rate of the concentrated waste liquid discharged from the concentrated waste liquid tank 17; a drainage treatment device 3 for treating the mixture of drainage and concentrated waste liquid; a third flow measurement unit 10, installed upstream of the merging point with the concentrated waste liquid in the drainage discharge pipe 24, for measuring the flow rate of the drainage discharged from the adjusting tank 1; and a calculation unit 6 for estimating the drainage load in the inflow section of the drainage treatment device 3 (downstream of the merging point with the concentrated waste liquid in the drainage discharge pipe 24). The calculation unit 6 is, for example, a computer. The calculation unit 6 acquires measurement results from various measuring machines. Furthermore, the calculation unit 6 controls the opening and closing of valves or the starting and stopping of pumps, as described later.

[0031] Drainage from a single series flows into the regulating tank 1, or drainage from multiple series simultaneously or at different times merges at the drainage inflow pipe 23 and flows into the regulating tank 1. The water quality of the drainage flowing into the regulating tank 1 is not particularly limited. However, if the drainage is subjected to at least one of the following conditions for a certain period of time (e.g., more than 20% of the total drainage inflow time): a water temperature above 40°C, a pH below 4 or above, a pH above 9, or an oxidation-reduction potential (ORP) above 750 mV, then the adhesion of sludge to the first turbidity load measuring unit 4 and the first flow rate measuring unit 5 is suppressed, preventing measurement errors caused by sludge, thus easily achieving the effects of the invention.

[0032] The first turbidity load measuring unit 4 measures the turbidity load of the drainage flowing into the regulating tank 1 periodically or continuously at relatively short time intervals. In this embodiment, an example of measuring TOC concentration as turbidity load is described, but the measured item is not limited to TOC concentration, and may also be other indicators representing turbidity load such as the concentration of a specific substance, chemical oxygen demand (COD) concentration, or suspended solids (SS). In addition, the measured turbidity load includes items related to turbidity load, such as conductivity or Brix saccharide content.

[0033] The first turbidity load measuring unit 4 measures the turbidity load (TOC concentration) by immersing the measuring instrument in the drainage at a location further upstream than the adjustment tank 1 and, in the case of multiple series, further downstream than the confluence of drainage from each series.

[0034] The purpose of conditioning tank 1 is to adjust and mitigate changes in water quality or quantity, defined as having a hydraulic retention time (HRT) of 30 minutes or more. There are no particular limitations on the volume or other specifications of conditioning tank 1. Multiple conditioning tanks 1 can also be configured in parallel.

[0035] The first flow measurement unit 5, which measures the flow rate of the drainage flowing into the regulating tank 1, can be a flow meter. When the regulating tank 1 is circulated in batches, the flow rate can be calculated based on the increase in water level per unit time in the regulating tank 1. When the regulating tank 1 is circulated continuously, the flow rate of the drainage flowing into the regulating tank 1 can be calculated based on the sum of the change in the storage volume of the regulating tank 1 and the discharge flow rate from the regulating tank 1. In this case, a level gauge needs to be installed in the regulating tank 1 as the first flow measurement unit 5.

[0036] The concentrated waste liquid tank 17 is a tank for storing concentrated waste liquid with a high turbidity load that cannot be treated by drainage alone. Concentrated waste liquid from a single series flows into the concentrated waste liquid tank 17, or concentrated waste liquid from multiple series simultaneously or at different times merges into the concentrated waste liquid inflow piping 25 and flows into the concentrated waste liquid tank 17. The turbidity load of the concentrated waste liquid is higher than the maximum design value of the turbidity load variation of the drainage flowing into the regulating tank 1. There are no particular limitations on the volume, specifications, or number of concentrated waste liquid tanks 17. Alternatively, the concentrated waste liquid tank 17 may not be a permanent tank, but a mobile tank or other container may be used. The tank storing the concentrated waste liquid can be moved to the drainage treatment system of the present invention at the site of concentrated waste liquid discharge for temporary installation and treatment. Alternatively, the tank storing the concentrated waste liquid can be moved to the drainage treatment system of the present invention, and the concentrated waste liquid can be directly introduced from the tank into the permanent concentrated waste liquid tank 17. In these cases, the concentrated waste liquid inflow piping 25 is not required. Concentrated waste liquids include, for example, the brine produced during plum processing, waste syrup produced during beverage manufacturing, and plating waste liquid.

[0037] The second turbidity load measuring unit 18 periodically or continuously measures the turbidity load of the concentrated waste liquid in the concentrated waste liquid tank 17 at relatively short time intervals. For example, the second turbidity load measuring unit 18 measures the turbidity load of the same measurement item as the first turbidity load measuring unit 4. As described above, in this embodiment, the TOC concentration is measured as the turbidity load.

[0038] There are no particular limitations on the method for determining the TOC concentration of concentrated waste liquid. The TOC concentration can be determined by dilution, or other related indicators can be determined. The second turbidity load measuring unit 18 can also measure the turbidity load (TOC concentration) by immersing the measuring instrument in the concentrated waste liquid.

[0039] The second flow measurement unit 19 measures the flow rate of concentrated waste liquid flowing from the concentrated waste liquid tank 17 into the drainage treatment equipment 3. The second flow measurement unit 19 can measure the flow rate using a flow meter, or it can calculate the flow rate using the decrease in water level per unit time in the concentrated waste liquid tank 17. In this case, a level gauge needs to be installed in the concentrated waste liquid tank 17 as the second flow measurement unit 19. If the flow rate of the concentrated waste liquid is fixed at a predetermined value, the measurement can be omitted.

[0040] A transfer pump 11, installed in the drainage discharge pipe 24, transports the drainage from the regulating tank 1 to the drainage treatment equipment 3. A third flow measurement unit 10, also installed in the drainage discharge pipe 24, measures the flow rate of the drainage discharged from the regulating tank 1. The third flow measurement unit 10 can be a flow meter, or it can be calculated using the decrease in water level in the regulating tank 1 per unit time. In this case, a level gauge needs to be installed in the regulating tank 1 as the third flow measurement unit 10.

[0041] A transfer pump 20, installed in the concentrated waste liquid discharge pipe 26, transports the concentrated waste liquid in the concentrated waste liquid tank 17 to the drainage flowing in the drain discharge pipe 24. The drainage and concentrated waste liquid merge and mix, and the mixture is then transported to the drainage treatment equipment 3 through the drain discharge pipe 24. Figure 1 In the example shown, the drainage and concentrated waste liquid are mixed on the downstream side of the third flow measurement unit 10.

[0042] Wastewater treatment equipment 3 removes dirt or oil from the mixture of concentrated wastewater that has been combined with the wastewater. There is no particular limitation on the treatment method or the number of systems for the mixture. Examples of treatment methods include biological treatment (including aerobic and anaerobic processes), physicochemical treatments such as Fenton treatment or activated carbon treatment, or neutralization treatment or coagulation and separation treatment depending on the type of wastewater.

[0043] The calculation unit 6 uses the TOC concentration measured by the turbidity load measuring unit 4 and the flow rate measured by the first flow measuring unit 5 to estimate the TOC concentration at the outlet of the adjustment tank 1.

[0044] The method of estimating the TOC concentration at the outlet of the regulating tank 1 using the TOC concentration measured by the turbidity load measuring unit 4 (the TOC concentration measured at a location upstream of the regulating tank 1) and the flow rate measured by the first flow rate measuring unit 5 can be performed using various proposed concentration calculation models for stagnant water tanks. However, depending on whether the regulating tank 1 is continuously or partially circulated, different estimation methods can be used, as shown below.

[0045] <When water is continuously flowing>

[0046] Estimation method (1)-1

[0047] The TOC concentration (mg / L) at the outlet of conditioning tank 1 is estimated by moving average the TOC concentration measured upstream of conditioning tank 1 over a period close to the residence time in conditioning tank 1. For example, if the residence time in conditioning tank 1 is 50 minutes, the average of the TOC concentration measurements from the present to 50 minutes ago can be considered as the TOC concentration discharged from conditioning tank 1.

[0048] Estimation method (2)-1

[0049] Based on the TOC concentration and flow rate measured upstream of the equalization tank 1, the change in TOC concentration of the wastewater flowing into the equalization tank 1 is estimated using a fully mixed tank model, thereby estimating the TOC concentration (mg / L) at the outlet of the equalization tank 1.

[0050] <During phased water supply>

[0051] Estimation method (3)-1

[0052] The total TOC weight (g) flowing into the equalization tank 1 is divided by the total water volume (m³) flowing into the equalization tank 1. 3 Estimate the TOC concentration (mg / L) at the outlet of regulating tank 1. To accurately determine the total TOC weight or total water volume flowing into regulating tank 1, ideally, obtain the inlet valve opening / closing signal or pump start / stop signal of regulating tank 1, and calculate the load by accumulating the TOC concentration and water volume from the time the inlet valve is "open" to "closed" or the time the pump operates. If it is difficult to obtain valve opening / closing signals or pump start / stop signals, the timing of drainage flowing into regulating tank 1 can also be determined based on changes in the water level of regulating tank 1.

[0053] The calculation unit 6 uses the TOC concentration at the outlet of the adjustment tank 1 estimated by any one of the estimation methods (1)-1, (2)-1, and (3)-1, the flow rate at the outlet of the adjustment tank 1 measured by the third flow measurement unit 10, the TOC concentration of the concentrated waste liquid measured by the second turbidity load measurement unit 18, and the flow rate of the concentrated waste liquid flowing into the drainage treatment measured by the second flow measurement unit 19, to estimate the drainage load (kg-TOC / day) in the inflow section (drainage treatment inflow section) of the drainage treatment equipment 3 using the following formula 1.

[0054] Formula 1: Drainage load (kg - TOC / day) = {TOC concentration of drainage at the outlet of the adjusting tank (mg / L) × Flow rate of drainage at the outlet of the adjusting tank (m³)} 3 / h) + TOC concentration of the combined concentrated waste liquid (mg / L) × Flow rate of the combined concentrated waste liquid (m 3 / h)}×24(h) / 1000

[0055] Furthermore, the "TOC concentration of the confluent concentrated waste liquid" in Formula 1 can be directly obtained from the measurement results of the second turbidity load measuring unit 18, but it is more preferable to use the TOC concentration of the concentrated waste liquid at the confluence point, which is estimated by taking into account the residence time from the TOC concentration measurement location (e.g., the concentrated waste liquid tank 17) to the confluence point. For example, if the time from the discharge of the concentrated waste liquid from the concentrated waste liquid tank 17 to the arrival at the confluence point is 1 minute, the average value of the TOC concentration measurement results of the second turbidity load measuring unit 18 up to 1 minute ago can be used to estimate the "TOC concentration of the confluent concentrated waste liquid".

[0056] Based on the estimated drainage load at the drainage treatment inlet, the calculation unit 6 determines whether there is a problem with the flow of the mixed liquid into the drainage treatment equipment 3. If the calculation unit 6 determines that the drainage load is high (the drainage load is above a specified value) and the drainage treatment may fail, it closes valve 21 and opens valve 12, stopping the transfer pump 20, thereby creating a state where the concentrated waste liquid is stored in the concentrated waste liquid tank 17. The calculation unit 6 continues to estimate the drainage load.

[0057] Subsequently, at the estimated time point when the drainage load decreases (the drainage load is less than a specified value), valve 21 is opened, and transfer pump 20 is controlled to convey concentrated waste liquid from concentrated waste liquid tank 17 to drainage discharge pipe 24. The concentrated waste liquid from concentrated waste liquid tank 17 is mixed with the drainage from adjusting tank 1 and flows into drainage treatment equipment 3 through drainage discharge pipe 24. Preferably, transfer pump 20 is controlled to adjust the flow rate or inflow time of the concentrated waste liquid conveyed from concentrated waste liquid tank 17 to drainage discharge pipe 24 to ensure that drainage treatment does not fail. In this case, the flow rate or inflow time is adjusted so that the estimated drainage load does not exceed a specified value, and the concentrated waste liquid is conveyed to drainage discharge pipe 24.

[0058] The computing unit 6 can display information on a monitor or similar screen so that the start and stop times of the transfer pump 20 can be known, and the operator can manually rotate the transfer pump 20 according to the display.

[0059] According to this embodiment, by knowing the turbidity load (or items related to turbidity load) and flow rate of the wastewater continuously measured on the upstream side of the adjustment tank 1, and the turbidity load (or items related to turbidity load) and flow rate of the concentrated waste liquid flowing directly into the wastewater treatment on the downstream side of the adjustment tank 1, the wastewater load based on the wastewater and the load based on the concentrated waste liquid are added together to estimate the wastewater load at the inflow point of the wastewater treatment. Based on the estimated value, the flow rate or inflow time point of the concentrated waste liquid is adjusted, thereby reducing the amount of industrial waste and stabilizing the wastewater treatment.

[0060] [Second Implementation]

[0061] exist Figure 2 The diagram shows a schematic structure of the drainage treatment system according to the second embodiment. This embodiment is similar to... Figure 1 Compared to the first embodiment shown, the difference lies in the following aspects: The adjusting tank 2 is arranged in series with the adjusting tank 1 between the adjusting tank 1 and the drainage treatment device 3. Furthermore, the drainage treatment system includes: a relay pipe 27 connected to the downstream side of the adjusting tank 1 and transferring drainage to the adjusting tank 2; and a fourth flow measurement unit 8, which measures the flow rate of the drainage flowing into the adjusting tank 2, which is installed in the relay pipe 27. The volume and other specifications of the adjusting tank 2 are not particularly limited. A plurality of adjusting tanks 2 may also be arranged in parallel. Figure 2 In the middle, to and Figure 1 The same parts as those in the first embodiment shown are marked with the same symbols and the description is omitted.

[0062] The drainage water transported from the adjustment tank 1 by the transfer pump 11 provided in the relay pipe 27 flows into the adjustment tank 2 through the relay pipe 27. The fourth flow rate measurement unit 8 measures the flow rate of the drainage water flowing into the adjustment tank 2. The fourth flow rate measurement unit 8 can be a flow meter. When the adjustment tank 2 is filled with water in batches, the flow rate can be calculated based on the increase in the water level per unit time in the adjustment tank 2. When the adjustment tank 2 is filled with water continuously, the flow rate of the drainage water flowing into the adjustment tank 2 can be calculated based on the sum of the change in the storage volume of the adjustment tank 2 and the discharge flow rate from the adjustment tank. In this case, a liquid level gauge needs to be provided in the adjustment tank 2 as the fourth flow rate measurement unit 8.

[0063] The transfer pump 13 provided in the drainage discharge pipe 24 transports the drainage water in the adjustment tank 2 to the drainage treatment device 3. The third flow rate measurement unit 10 measures the flow rate of the drainage water at the outlet of the adjustment tank 2. Downstream of the third flow rate measurement unit 10, the drainage water sent out from the adjustment tank 2 merges and mixes with the thickened waste liquid, and the mixed liquid flows into the drainage treatment device 3 through the drainage discharge pipe 24.

[0064] In the above structure, the operation unit 6 first estimates the TOC concentration at the outlet of the adjustment tank 1. Similar to Figure 1 the first embodiment shown, the estimation method is different depending on whether the adjustment tank 1 is filled with water continuously or in batches. When filled with water continuously, the TOC concentration (estimated value A) at the outlet of the adjustment tank 1 is estimated by the above-mentioned estimation method (1)-1 or estimation method (2)-1, and when filled with water in batches, the TOC concentration (estimated value A) at the outlet of the adjustment tank 1 is estimated by the estimation method (3)-1.

[0065] Next, based on the TOC concentration (estimated value A) at the outlet of the adjustment tank 1 obtained as above and the flow rate of the drainage water flowing into the adjustment tank 2 measured by the fourth flow rate measurement unit 8, the TOC concentration (estimated value B) at the outlet of the adjustment tank 2 is estimated. Here, the estimation method is also different depending on whether the adjustment tank 2 is filled with water continuously or in batches. When filled with water continuously, the TOC concentration (estimated value B) at the outlet of the adjustment tank 2 is estimated using the following estimation method (1)-2 or estimation method (2)-2, and when filled with water in batches, the TOC concentration (estimated value B) at the outlet of the adjustment tank 2 is estimated using the estimation method (3)-2.

[0066] Estimation method (1)-2

[0067] The TOC concentration (estimated value B) at the outlet of the adjustment tank 2 is estimated by moving-averaging the TOC concentration (estimated value A) over a time close to the residence time in the adjustment tank 2.

[0068] Estimation method (2)-2

[0069] Based on the TOC concentration (estimated value A) and the flow rate into the equalization tank 2, the change in TOC concentration of the wastewater flowing into the equalization tank 2 is estimated using a fully mixed tank model, thereby estimating the TOC concentration (mg / L) at the outlet of the equalization tank 2.

[0070] Estimation method (3)-2

[0071] The total TOC weight (g) flowing into the equalization tank 2 is divided by the total water volume (m³) flowing into the equalization tank 2. 3 Estimate the TOC concentration (mg / L) at the outlet of adjustment tank 2.

[0072] Using the TOC concentration (estimated value B) at the outlet of the adjusting tank 2 thus obtained, the flow rate of the drainage at the outlet of the adjusting tank 2 measured by the third flow measurement unit 10, the TOC concentration and flow rate of the concentrated waste liquid, the drainage load (kg-TOC / day) is estimated using Equation 1. In this embodiment, "adjusting tank outlet" in Equation 1 corresponds to the outlet of the adjusting tank 2.

[0073] Based on the estimated drainage load at the drainage inlet, the calculation unit 6 determines whether there is a problem with the flow of the mixed liquid into the drainage treatment equipment 3. The calculation unit 6 controls the start and stop of the transfer pump 20 and the opening and closing of the valve 21 to adjust the flow rate or inflow time of the concentrated waste liquid transported from the concentrated waste liquid tank 17 to the drainage discharge pipe 24, so that the drainage treatment will not fail. In this case, the flow rate or inflow time is adjusted so that the estimated drainage load does not exceed a specified value, and the concentrated waste liquid is transported to the drainage discharge pipe 24.

[0074] exist Figure 2 The diagram shows a structure with two adjusting channels (adjusting channel 1 and adjusting channel 2) connected in series, but it can also be configured with three or more adjusting channels connected in series. The more adjusting channels are connected in series, the longer it takes for the estimated drainage load to actually reach the drainage treatment equipment 3, making it easier to take countermeasures before the drainage load exceeds the specified value, which is effective in this respect.

[0075] [Third Implementation Method]

[0076] exist Figure 3 The diagram shows a schematic structure of the drainage treatment system according to the third embodiment. This embodiment is similar to... Figure 2 Compared to the second embodiment shown, it differs in the following aspects: relative to the adjustment slot 2A (corresponding to Figure 2Adjusting tank 2A ​​and adjusting tank 2B are connected in parallel, and drainage is returned from adjusting tank 2B to adjusting tank 1. The drainage treatment system includes: a branch pipe 28, branching from the relay pipe 27 and connected to adjusting tank 2B; a return pipe 29, connected to the downstream side of adjusting tank 2B and returning drainage to adjusting tank 1; a fifth flow measurement unit 9, which measures the flow rate of drainage flowing into adjusting tank 2B connected to the branch pipe 28; and a sixth flow measurement unit 22, which measures the flow rate of drainage discharged from adjusting tank 2B connected to the return pipe 29. The volume and other specifications of adjusting tanks 2A and 2B are not particularly limited. Figure 3 In the middle, to and Figure 2 The same parts shown in the second embodiment are marked with the same symbols and the description is omitted.

[0077] The drainage pumped from the regulating tank 1 by the transfer pump 11 installed in the relay pipe 27 branches and flows into regulating tank 2A ​​or regulating tank 2B. The destination from regulating tank 1 is switched by controlling the opening and closing of valve 15, located downstream of the branch point in the relay pipe 27, and valve 16, located in the branch pipe 28. A fourth flow measuring unit 8 installed in the relay pipe 27 measures the flow rate of the drainage flowing into regulating tank 2A. A fifth flow measuring unit 9 installed in the branch pipe 28 measures the flow rate of the drainage flowing into regulating tank 2B. The fourth and fifth flow measuring units 8 and 9 can be flow meters, which can calculate the flow rate based on the increase in water level per unit time in regulating tanks 2A and 2B when water is supplied to regulating tanks 2A and 2B in batches. When the flow rate is calculated based on the increase in water level per unit time in adjustment tanks 2A and 2B, level gauges need to be installed in adjustment tanks 2A and 2B respectively as the fourth flow measurement unit 8 and the fifth flow measurement unit 9.

[0078] The transfer pump 13, installed in the drainage discharge pipe 24, transports the drainage in the regulating tank 2A ​​to the drainage treatment equipment 3. The third flow measurement unit 10, installed in the drainage discharge pipe 24, measures the flow rate of the drainage at the outlet of the regulating tank 2A. Further downstream (rear section) than the third flow measurement unit 10, the drainage from the regulating tank 2A ​​merges and mixes with the concentrated waste liquid, and the mixture flows into the drainage treatment equipment 3 through the drainage discharge pipe 24.

[0079] The transfer pump 14, installed in the return pipe 29, returns the drainage in the adjustment tank 2B to the adjustment tank 1.

[0080] The sixth flow measurement unit 22, installed on the return pipe 29, measures the flow rate of the drainage returned from the adjustment tank 2B to the adjustment tank 1. This can be measured using a flow meter or calculated based on the decrease in water level in the adjustment tank 2B per unit time. In the case of calculating based on the decrease in water level in the adjustment tank 2B per unit time, a level gauge needs to be installed in the adjustment tank 2B as the fifth flow measurement unit 9.

[0081] In this embodiment, the condition for the adjustment tank 2B that returns drainage to the adjustment tank 1 is that water is supplied in batches. The adjustment tank 1 and the adjustment tank 2A ​​can be either continuously supplied with water or supplied in batches. More than one adjustment tank 2A ​​can be provided, and multiple adjustment tanks 2A can also be configured in parallel.

[0082] In the structure, the calculation unit 6 first estimates the TOC concentration (estimated value C) of the drainage in the adjustment tank 2B by the following estimation method (3)-3, based on the TOC concentration measured by the first turbidity load measuring unit 4 on the upstream side of the adjustment tank 1 and the flow rate measured by the fifth flow rate measuring unit 9.

[0083] Estimation method (3)-3

[0084] The total TOC weight (g) flowing into the equalization tank 2B is divided by the total water volume (m³) flowing into the equalization tank 2B. 3 Estimate the TOC concentration (mg / L) in adjustment tank 2B.

[0085] Next, the calculation unit 6 estimates the TOC concentration (estimated value C) at the outlet of the adjustment tank 1 based on the TOC concentration (estimated value C) of the adjustment tank 2B obtained as described above, the flow rate measured by the sixth flow measurement unit 22, and the TOC concentration measured by the first turbidity load measurement unit 4 and the flow rate measured by the first flow measurement unit 5 on the upstream side of the adjustment tank 1. The estimation is performed by estimation method (2)-3 when the adjustment tank 1 is continuously supplied with water, and by estimation method (3)-4 when the adjustment tank 1 is supplied with water in batches.

[0086] Estimation method (2)-3

[0087] Based on the TOC concentration measured by the first turbidity load measuring unit 4, the flow rate measured by the first flow rate measuring unit 5, the TOC concentration (estimated value C) of the adjusting tank 2B, and the flow rate flowing from the adjusting tank 2B into the adjusting tank 1, the change in the concentration of the wastewater flowing into the adjusting tank 1 is estimated using a fully mixed tank model, thereby estimating the TOC concentration (mg / L) at the outlet of the adjusting tank 1.

[0088] Estimation methods (3)-4

[0089] The total TOC weight (g) flowing into the equalization tank 1 is divided by the total water volume (m³) flowing into the equalization tank 1. 3The TOC concentration (mg / L) at the outlet of equalization tank 1 is estimated. The total TOC weight and total water volume are calculated by adding the TOC weight and water volume measured on the upstream side of equalization tank 1 to the TOC weight and water volume returned from equalization tank 2B.

[0090] Next, the calculation unit 6 estimates the TOC concentration (estimated value D) at the outlet of the regulating tank 1 and the flow rate into the regulating tank 2A ​​based on the TOC concentration (estimated value E) obtained as described above. When the regulating tank 2A ​​is continuously supplied with water, the TOC concentration (estimated value E) at the outlet of the regulating tank 2A ​​is estimated using estimation method (1)-3 or estimation method (2)-4. When the regulating tank 2A ​​is supplied with water in batches, the TOC concentration (estimated value E) at the outlet of the regulating tank 2A ​​is estimated using estimation method (3)-5.

[0091] Estimation method (1)-3

[0092] The TOC concentration (mg / L) at the outlet of conditioning tank 2A ​​was estimated by moving average the TOC concentration (estimated value D) over a period of time close to the residence time in conditioning tank 2A.

[0093] Estimation method (2)-4

[0094] Based on the TOC concentration (estimated value D) and the flow rate into the equalization tank 2A, the change in the concentration of the wastewater flowing into the equalization tank 2A ​​is estimated using a fully mixed tank model, thereby estimating the TOC concentration (mg / L) at the outlet of the equalization tank 2A.

[0095] Estimation method (3)-5

[0096] The total TOC weight (g) flowing into the equalization tank 2A ​​is divided by the total water volume (m³) flowing into the equalization tank 2A. 3 Estimate the TOC concentration (mg / L) at the outlet of adjustment tank 2A.

[0097] Using the TOC concentration (estimated value E) at the outlet of the adjusting tank 2A ​​thus determined, the flow rate measured by the third flow measurement unit 10, the TOC concentration and flow rate of the concentrated waste liquid, the drainage load (kg-TOC / day) is estimated using Equation 1. In this embodiment, "adjusting tank outlet" in Equation 1 corresponds to the outlet of the adjusting tank 2A.

[0098] Based on the estimated drainage load at the drainage treatment inlet, the calculation unit 6 determines whether there is a problem with the flow of the mixed liquid into the drainage treatment equipment 3. The calculation unit 6 controls the start and stop of the transfer pump 20 and the opening and closing of the valve 21 to adjust the flow rate or inflow time of the concentrated waste liquid transported from the concentrated waste liquid tank 17 to the drainage discharge pipe 24, so that the drainage treatment will not fail. In this case, the flow rate or inflow time is adjusted in a way that the estimated drainage load does not exceed the specified value, and the concentrated waste liquid is transported to the drainage discharge pipe 24.

[0099] [Fourth Implementation Method]

[0100] exist Figure 4 The diagram shows a schematic structure of the drainage treatment system according to the fourth embodiment. This embodiment is similar to... Figure 1 The first embodiment shown differs from the previous one in that the concentrated waste liquid transported from the concentrated waste liquid tank 17 does not merge with the drainage discharge pipe 24 but instead merges with the adjusting tank 1. Figure 4 In the middle, to and Figure 1 The same parts as those in the first embodiment shown are marked with the same symbols and the description is omitted.

[0101] In the structure, the concentrated waste liquid discharge pipe 26 causes the concentrated waste liquid discharged from the concentrated waste liquid tank 17 to merge in the adjustment tank 1. In the adjustment tank 1, the wastewater and concentrated waste liquid mix to form a mixed liquid, and the wastewater discharge pipe 24 causes the mixed liquid discharged from the adjustment tank 1 to flow into the wastewater treatment system.

[0102] The calculation unit 6 uses the TOC concentration measured by the turbidity load measuring unit 4 and the flow rate measured by the first flow rate measuring unit 5 to estimate the TOC concentration (from raw water) at the outlet of the conditioning tank 1. The so-called "raw water" refers to the liquid in the conditioning tank 1 when the concentrated waste liquid has not merged with the flow.

[0103] The method for estimating the TOC concentration (from raw water) at the outlet of the regulating tank 1 using the TOC concentration measured by the turbidity load measuring unit 4 (the TOC concentration measured on the upstream side of the regulating tank 1) and the flow rate measured by the first flow measuring unit 5 can be carried out by various proposed concentration calculation models for stagnant water tanks. However, depending on whether the regulating tank 1 is continuously or partially circulated, different estimation methods can be used as shown below.

[0104] <When water is continuously flowing>

[0105] Estimation method (1)-4

[0106] The TOC concentration (from raw water) at the outlet of equalization tank 1 is estimated (mg / L) by performing a moving average of the TOC concentration measured upstream of equalization tank 1 over a period close to the residence time in equalization tank 1. For example, if the residence time in equalization tank 1 is 50 minutes, the average of the TOC concentration measurements taken upstream of equalization tank 1 up to 50 minutes ago can be considered as the TOC concentration discharged from equalization tank 1 (from raw water).

[0107] Estimation method (2)-5

[0108] Based on the TOC concentration and flow rate measured upstream of the equalization tank 1, the change in TOC concentration of the wastewater flowing into the equalization tank 1 is estimated using a fully mixed tank model, thereby estimating the TOC concentration (from raw water) at the outlet of the equalization tank 1 (mg / L).

[0109] <During phased water supply>

[0110] Estimation method (3)-6

[0111] The total TOC weight (g) flowing into the equalization tank 1 is divided by the total water volume (m³) flowing into the equalization tank 1. 3 The TOC concentration (from raw water) at the outlet of equalization tank 1 (mg / L) is estimated. To accurately determine the total TOC weight or total water volume flowing into equalization tank 1, ideally, the inlet valve opening / closing signal or pump start / stop signal of equalization tank 1 should be obtained. The TOC concentration (from raw water) and water volume during the time the inlet valve is "open" to "closed" or the pump is operating can be accumulated to calculate the load. If it is difficult to obtain valve opening / closing signals or pump start / stop signals, the time point when drainage flows into equalization tank 1 can also be determined based on the water level changes in equalization tank 1.

[0112] The calculation unit 6 uses the TOC concentration (from raw water) at the outlet of the adjustment tank 1 estimated by any of the estimation methods (1)-4, (2)-5, and (3)-6, the flow rate at the outlet of the adjustment tank 1 measured by the third flow measurement unit 10, the TOC concentration of the concentrated waste liquid measured by the second turbidity load measurement unit 18, and the flow rate of the concentrated waste liquid discharged from the concentrated waste liquid tank 17 measured by the second flow measurement unit 19 to estimate the drainage load (kg-TOC / day) in the drainage treatment inflow unit.

[0113] When the concentrated waste liquid is made to merge closer to the third flow measurement unit 10, the flow rate of the drainage (mixed liquid) at the outlet of the adjustment tank 1 is the sum of the flow rate from the raw water and the flow rate of the concentrated waste liquid. Therefore, the drainage load is estimated by the following formula 2.

[0114] Formula 2: Drainage load (kg - TOC / day) = [TOC concentration at the outlet of the conditioning tank (from raw water) (mg / L) × {flow rate of the drainage (mixed liquor) at the outlet of the conditioning tank (m³)] 3 / h) - Flow rate of concentrated waste liquid (m³) 3 / h)}+TOC concentration of the combined concentrated waste liquid (mg / L)×flow rate of the combined concentrated waste liquid (m 3 [ / h)]×24(h) / 1000

[0115] Furthermore, in this embodiment, the concentrated waste liquid is merged and mixed in the adjustment tank 1. However, as long as it is upstream of the third flow measurement unit 10, the concentrated waste liquid can also be merged downstream of the adjustment tank 1. In this case, the drainage load can also be estimated using Equation 2. In this case, the "TOC concentration of the merged concentrated waste liquid" in Equation 2 ideally also takes into account the residence time from the time the concentrated waste liquid merges in the adjustment tank 1 until the location calculated as the drainage load. For example, if the residence time from the time the concentrated waste liquid merges until the location calculated as the drainage load is 30 minutes, the average value of the TOC concentration measurement results from the second turbidity load measurement unit 18 up to 30 minutes ago can be used to estimate the "TOC concentration of the merged concentrated waste liquid".

[0116] [Fifth Implementation Method]

[0117] exist Figure 5 The diagram shows a schematic structure of the drainage treatment system according to the fifth embodiment. This embodiment is similar to... Figure 2 The second embodiment shown differs from the previous one in the following aspects: the concentrated waste liquid transported from the concentrated waste liquid tank does not merge with the drainage discharge pipe 24 but instead merges with the adjusting tank 2. Figure 5 In the middle, to and Figure 2 The same parts shown in the second embodiment are marked with the same symbols and the description is omitted.

[0118] In the structure, the concentrated waste liquid discharge pipe 26 causes the concentrated waste liquid discharged from the concentrated waste liquid tank 17 to merge in the adjustment tank 2. In the adjustment tank 2, the wastewater and concentrated waste liquid mix to form a mixed liquid, and the wastewater discharge pipe 24 causes the mixed liquid discharged from the adjustment tank 2 to flow into the wastewater treatment system.

[0119] Similar to the second embodiment, the calculation unit 6 first estimates the TOC concentration (estimated value A) at the outlet of the adjustment tank 1 using the estimation method (1)-1 or the estimation method (2)-1 when water is continuously supplied, and estimates the TOC concentration (estimated value A) at the outlet of the adjustment tank 1 using the estimation method (3)-1 when water is supplied in batches.

[0120] Next, based on the TOC concentration at the outlet of the regulating tank 1 (estimated value A) obtained as described above and the flow rate of the drainage flowing into the regulating tank 2 measured by the fourth flow measurement unit 8, the TOC concentration at the outlet of the regulating tank 2 (from the raw water) (estimated value B) is estimated. Here, the estimation method also differs depending on whether the regulating tank 2 is continuously or partially circulated. In the case of continuous water circulation, the following estimation methods (1)-5 or (2)-6 are used to estimate the TOC concentration at the outlet of the regulating tank 2 (from the raw water) (estimated value B). In the case of partial water circulation, estimation method (3)-7 is used to estimate the TOC concentration at the outlet of the regulating tank 2 (from the raw water) (estimated value B).

[0121] Estimation method (1)-5

[0122] The TOC concentration (from raw water) at the outlet of conditioning tank 2 (mg / L) was estimated by moving average the TOC concentration (estimated value A) over a period of time close to the residence time in conditioning tank 2.

[0123] Estimation Method (2) - 6

[0124] Based on the TOC concentration (estimated value A) and the flow rate into equalization tank 2, the change in the concentration of wastewater flowing into equalization tank 2 is estimated using a fully mixed tank model, thereby estimating the TOC concentration (from raw water) at the outlet of equalization tank 2 (mg / L).

[0125] Estimation method (3)-7

[0126] The total TOC weight (g) flowing into the equalization tank 2 is divided by the total water volume (m³) flowing into the equalization tank 2. 3 Estimate the TOC concentration (from raw water) at the outlet of adjustment tank 2 (mg / L).

[0127] Using the TOC concentration (from raw water) (estimated value B) at the outlet of the conditioning tank 2 obtained in this way, the flow rate of the wastewater at the outlet of the conditioning tank 2 measured by the third flow measurement unit 10, the TOC concentration and flow rate of the concentrated waste liquid, the drainage load (kg-TOC / day) is estimated. When the concentrated waste liquid is merged at a point further forward than the third flow measurement unit 10, the flow rate of the wastewater (mixed liquid) at the outlet of the conditioning tank 2 is the sum of the flow rate from the raw water and the flow rate of the concentrated waste liquid, and therefore the drainage load is estimated using the above formula 2.

[0128] Furthermore, in this embodiment, the concentrated waste liquid is made to merge and mix in the adjusting tank 2. However, as long as it is upstream of the third flow measurement unit 10, the concentrated waste liquid can also be made to merge at any position downstream of the adjusting tank 1. In this case, the drainage load can also be estimated using Equation 2.

[0129] In the first to fifth embodiments, the following structure was described: the structure in which the calculation unit 6 performs calculations such as estimating the turbidity load at the outlet of the adjustment tank and estimating the drainage load at the inflow of the drainage treatment unit was described. However, the calculation unit 6 may be composed of a single computer or may be processed in a distributed manner by multiple computers.

[0130] The present invention has been described in detail using specific methods, but those skilled in the art will recognize that various modifications can be made without departing from the intent and scope of the invention.

[0131] This application is based on Japanese Patent Application No. 2023-191699, filed on November 9, 2023, the entire contents of which are incorporated herein by reference.

[0132] Explanation of reference numerals in the attached figures

[0133] 1, 2, 2A, 2B: Adjustment slots.

[0134] 3: Drainage treatment equipment.

[0135] 4: First Turbidity Load Measurement Section.

[0136] 5: First flow measurement section.

[0137] 6: Arithmetic unit.

[0138] 8: Fourth Flow Measurement Section.

[0139] 9: Fifth Flow Measurement Section.

[0140] 10: Third flow measurement section.

[0141] 11, 13, 14, 20: Transfer pumps.

[0142] 17: Concentrated waste liquid tank.

[0143] 18: Second Turbidity Load Measurement Section.

[0144] 19: Second flow measurement section.

[0145] 22: Sixth Flow Measurement Department.

[0146] 23: Drainage flows into the piping.

[0147] 24: Drainage outlet piping.

[0148] 25: Concentrated waste liquid flows into the piping.

[0149] 26: Dense waste liquid discharge piping.

[0150] 27: Relay piping.

[0151] 28: Division control tube.

[0152] 29: Return piping.

Claims

1. A method for estimating drainage load, which is a method for estimating the drainage load in the drainage treatment inlet section of a drainage treatment device that treats a mixture of wastewater and concentrated waste liquid, wherein, The first turbidity load of the wastewater was measured. Based on the first turbidity load, estimate the turbidity load from the drainage at the confluence point of the drainage and concentrated wastewater, or at a specified location downstream of that confluence point. The second turbidity load of the concentrated waste liquid was measured. The turbidity load of the concentrated waste liquid at the confluence point or the specified location is estimated based on the second turbidity load. The drainage load is estimated based on the estimated turbidity load from the drainage at the confluence point or the specified location and the estimated turbidity load of the concentrated waste liquid.

2. The method for estimating drainage load as described in claim 1, wherein, The wastewater is conveyed to the wastewater treatment equipment via a regulating channel. The confluence point is located downstream of the adjusting channel. The first sludge load is measured on the upstream side of the adjustment tank.

3. The method for estimating drainage load as described in claim 2, wherein, The first flow rate of the drainage flowing into the adjustment tank is measured. Using the first turbidity load and the first flow rate, estimate the turbidity load of the drainage at the confluence point.

4. The method for estimating drainage load as described in claim 1, wherein, The concentrated waste liquid is transported from the concentrated waste liquid tank to the confluence point. The second turbidity load was measured in the concentrated waste liquid tank. The second flow rate of the concentrated waste liquid discharged from the concentrated waste liquid tank was measured. Taking into account the residence time from the concentrated waste liquid tank to the confluence point, the turbidity load of the concentrated waste liquid at the confluence point is estimated based on the second turbidity load and the second flow rate.

5. A drainage treatment method, wherein, If the drainage load estimated using the method of claim 1 is above a specified value, concentrated waste liquid will not be transported to the confluence point.

6. The drainage treatment method as described in claim 5, wherein, If the estimated drainage load is less than a specified value, the concentrated waste liquid is transported to the confluence point at a flow rate not exceeding the specified value.

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