JP4900556B2 - Wastewater treatment plant operation management method - Google Patents

Description

  The present invention relates to various factories, livestock industries such as dairy farming, pig farming, and poultry farming, aquaculture, amusement facilities, industrial wastewater discharged from aquariums, water used for washing railway vehicles, automobile vehicles, ships, aircraft, etc. Wastewater such as water (for example, cooling water, sewage and balance / ballast water), domestic wastewater discharged from buildings, general households, accommodation facilities, bathing facilities, hospitals, restaurants, educational facilities such as schools, exercise facilities, etc. The present invention relates to an operation management method for a wastewater treatment plant that uses coagulation treatment and activated sludge treatment installed for the purpose of water purification.

Conventionally, activated sludge treatment apparatuses using aerobic microorganisms have been widely used to purify impurities contained in waste water. Here, the activated sludge treatment apparatus is composed of solid-liquid separation means such as an aeration tank and a sedimentation tank, and uses the metabolic activity of aerobic microorganisms to decompose organic substances contained mainly in wastewater and the like. A part is decomposed into CO ₂ and H ₂ O, and a part thereof is used for metabolic activity and self-proliferation of the aerobic microorganism itself.

Such activated sludge treatment is also known to perform activated sludge treatment after coagulation treatment in the previous stage. This is employed in order to reduce the load of impurities brought into the activated sludge process by aggregating suspended substances in the liquid to be treated in advance (see, for example, Patent Documents 1 and 2).
By the way, in order to perform stable flocculation treatment in a wastewater treatment plant, first, selection of a flocculating agent suitable for the component to be treated is essential. On the other hand, since the concentration of components to be treated of raw water flowing into the coagulation process changes every day, it is necessary to determine the amount of added chemical so that the coagulation process does not become excessive or insufficient. As for the flocculant used here, the drug brand, concentration and dosage amount optimal for aggregation are selected exclusively by jar test. Incidentally, the flocculant and the chemical injection conditions once determined are hardly changed unless the quality of the liquid to be treated is remarkably changed. For this reason, in some cases, the quality of the liquid to be treated is periodically or irregularly examined to reselect the optimal additive and chemical injection conditions for aggregation.

In many cases, the amount of drug added in the coagulation treatment is controlled in proportion to the amount of raw water flowing in based on the injection amount (ratio) determined in the jar test. In such agglomeration treatment, the turbidity concentration of the treated water is measured, the agglomeration state (floc diameter and inter-floc clarity) is measured, and feedback control is performed based on these measured values to add the amount of flocculant added. May be adjusted.
On the other hand, in the activated sludge treatment, the flow rate (setting of the raw water input amount, determination of the sludge return flow rate from the sedimentation tank to the aeration tank), excess sludge extraction amount, dissolved oxygen concentration, and the like are managed.

First, the raw water input amount is set in advance so that the raw water does not overflow from the adjustment tank or the storage tank that receives the drainage. On the other hand, the sludge return flow rate is generally controlled so that the return ratio (sludge return flow rate / raw water input flow rate) slightly exceeds [1], and solid-liquid separation of sludge and supernatant water in the sedimentation basin is also performed. It is determined in consideration of the interface level and its fluctuation speed. Specifically, if the interface level of the sedimentation basin rises (falls), the sludge return flow rate is increased (decreased). Moreover, based on the experience value in the past operation results in the wastewater treatment plant, the MLSS concentration of the activated sludge treatment device is measured, the increase / decrease from the previous day is calculated, and the surplus sludge extraction amount is determined in light of the experience value. Is done.
JP-A-6-134213 JP-A-6-315695

  However, the operation management method of the wastewater treatment plant described above is a method that relies exclusively on the experience and intuition of the operator. In other words, the operation management is entrusted to a skilled operator, and today's operating conditions are determined by measuring raw water inflow survey, MLSS concentration measurement, sedimentation basin sludge interface level, sedimentation settling (SV30), etc. The operator himself observed the sludge with a microscope and managed to adjust the flow rate of raw water and to turn on and off the drainage according to the situation. For this reason, there are no specific numerical indexes for operation management factors and judgment criteria based on the management indexes, and therefore automatic management and control of the wastewater treatment plant cannot be realized.

  By the way, in the activated sludge treatment, after treatment is generally performed in an aeration tank, treated water and sludge are separated in a subsequent sedimentation basin. In this sedimentation basin, the separation of treated water and sludge is based on natural sedimentation due to gravity, and therefore there is a problem that the solid-liquid separation performance is lowered unless the sludge is sufficiently flocked. This also has the same problem in a treatment system that combines an aeration process and a sedimentation separation process in one treatment tank, which is another example of the activated sludge treatment apparatus. On the other hand, even if a membrane separation means is provided as a solid-liquid separation means and sludge and water are separated by membrane separation, the membrane separation performance may change depending on the average particle size or particle size distribution of the sludge floc, It is known to clog. Therefore, the sludge property is a very important management item in the activated sludge treatment.

The sludge floc is a state in which a plurality of microorganisms are aggregated and formed by mucilage produced and discharged by the metabolic activity of the microorganism group. However, if the properties of the microorganism are poor, flock formation remains incomplete. In general, the causes of the microbial state and the causes of the deterioration of treated water are listed as follows.
[Factors causing microbial conditions]
(1) Dispersion: Occurs when the organic matter concentration in the raw water becomes extremely high and the ratio of the amount of organic matter to be treated (F) and the amount of microorganisms (M) (F / M ratio) is lost, resulting in overeating. To do.
(2) Dismantling: Occurs when the organic matter concentration in the raw water becomes extremely low and the balance of the F / M ratio is lost, resulting in starvation. Or it occurs when extremely hot water, strong acid, strong alkali, poisons that inhibit biological activity, etc. flow in.
[Cause of deterioration of treated water quality]
(1) Dispersion: Almost all sludge flocs are uniformly reduced and the sedimentation rate is lowered, so that sludge is likely to flow out of the system together with the treated water. For this reason, the quality of treated water deteriorates and the amount of water that can be fed into the raw water decreases.
(2) Dismantling: Sludge becomes fragile and part of the flocs have dropped off or literally disassembled as a whole, causing turbidity in the treated water. Part of the sludge is treated with the treated water. It is in a state where it tends to flow out. For this reason, the quality of treated water is deteriorated and the amount of water that can be fed into the raw water is reduced.

The coping method when the above-mentioned dispersed sludge or demolition sludge is generated is to optimize the F / M ratio. The F / M ratio is adjusted by adjusting the organic matter concentration in the raw water or the raw water flow rate or the MLSS concentration. Should be set to the optimum value.
However, the raw water flow rate cannot usually be changed. The MLSS concentration can be adjusted by the amount of excess sludge withdrawn, but the speed at which it can be changed is very slow. That is, when it is going to reduce the MLSS density | concentration by increasing discharge | emission of excess sludge, it may be restrict | limited by the limit of the capability of the dehydrator which dehydrates sludge.

On the other hand, when the sludge is not drawn, the microflora may change due to an increase in SRT, which may cause, for example, filamentous bulking. Therefore, there is a problem that it is difficult to make adjustment by following the change of the plant with only means for adjusting the MLSS concentration to the optimum value.
The present invention has been made to solve the above-described problems, and its object is to quantitatively determine the properties of activated sludge in a wastewater treatment plant, and to take quick and appropriate measures depending on the properties of the activated sludge. It is in providing the operation management method of the wastewater treatment plant which can do.

Therefore, while monitoring the state of the sludge floc in order to solve the above-mentioned problems, enumerating technologies required for feedback control of the operation conditions of the coagulation treatment and activated sludge,
(A) Sludge floc state monitoring method and quantification technology (B) Measures suitable for sludge floc state, ie, control of coagulation treatment and / or activated sludge side control technology (C) Selection technology of optimum measures that can be taken It becomes.

First, (A) “sludge floc state monitoring method and quantification technique” has been established, for example, as shown in the sludge property sensor of Japanese Patent Application No. 2005-23091. In addition, (B) “Measures in the state of sludge flocs, that is, control of agglomeration and / or control technology on the activated sludge side”
(B1) A method for controlling the chemical injection amount of the coagulation treatment and / or directly flowing into the aeration tank by bypassing a part or all of the coagulation raw water,
(B2) There is a method of adjusting the MLSS concentration by controlling the excess sludge extraction amount.

  The amount of surplus sludge withdrawn in (b2) is preferably determined by monitoring the sludge growth amount in the activated sludge treatment apparatus and using SRT as a guide, although details will be described later. Similarly, the MLSS concentration is preferably determined by a method of management based on SRT described later. Alternatively, in consideration of the solid-liquid separation capacity limit of the sedimentation basin in particular, control may be performed by setting a target concentration obtained using a 1D-flux theory, which will be described later, as a limit standard.

On the other hand, (C) “Optimal countermeasure selection technology that can be adopted” selects the optimal treatment for the plant in consideration of urgency and immediate effect .

In order to achieve the above-described object in view of such points, the operation management method for a wastewater treatment plant of the present invention has an agglomeration reaction treatment apparatus at the front stage and an activated sludge treatment apparatus provided with a solid-liquid separation means at the rear stage. An operation management method for a wastewater treatment plant,
Mass balance monitoring means for obtaining an increase / decrease amount of the activated sludge per hour in the activated sludge treatment apparatus and a sludge concentration rate in the solid-liquid separation means, and detecting the property of the activated sludge in the activated sludge treatment apparatus in a numerical manner A sludge property sensor that
The amount of sludge increased / decreased per hour in the activated sludge treatment device determined by the mass balance monitoring means, the sludge concentration rate in the solid / liquid separation means, and the activated sludge property information detected by the sludge property sensor, Control means for controlling the agglomeration reaction processing device for increasing / decreasing the COD component by changing the injection amount, changing the concentration of the chemical solution, or changing the brand of the chemical solution and / or a part or all of the raw water flowing into the agglomeration reaction processing device Raw water bypass control means for bypassing the activated sludge treatment device and / or MLSS concentration adjusting means for adjusting the MLSS concentration of the activated sludge treatment device by controlling the amount of excess sludge withdrawn from the activated sludge treatment device,
Adjusting the load of the activated sludge treatment apparatus by at least one of the control means for controlling the agglomeration reaction treatment apparatus, the raw water bypass treatment control means, and the MLSS concentration adjusting means to make the activated sludge have a preferable property. It is said.

Preferably, in the operation management method of the wastewater treatment plant, it is desirable to further define the limit capability of the solid-liquid separation means using 1D-flux theory. That is, the MLSS concentration adjusting means calculates the limit capability in the solid-liquid separation performance of the solid-liquid separation means, determines the control target value of the MLSS concentration of the activated sludge treatment apparatus based on the calculated result, and activates according to the control target value. It is desirable to control the amount of excess sludge withdrawn from the sludge treatment apparatus.
Therefore, since the operation management method of the above-mentioned wastewater treatment plant calculates the amount of increase / decrease per hour of the sludge in the system, the amount of surplus sludge extraction can be understood so that the guideline of the excess sludge extraction amount is obtained and the target value of the MLSS concentration is obtained. And MLSS concentration adjustment can be controlled.

Further, the operation management method for the wastewater treatment plant of the present invention comprises a coagulation reaction treatment device, an activated sludge treatment device equipped with a solid-liquid separation means, and a dewatering device for surplus sludge concentration and dewatering arranged in order from the front stage to the rear stage. A processing plant operation management method comprising:
Wherein a mass balance monitoring means for determining a sludge concentration rate increase or decrease the amount of sludge per hour in activated sludge treatment apparatus and in the solid-liquid separation means, the sludge for detecting the properties of the activated sludge in the activated sludge treatment apparatus to be quantified A property sensor and a dehydrating function monitoring means for detecting surplus processing capacity in the dewatering of sludge processed by the dehydrator,
Increase / decrease amount of activated sludge per hour in the activated sludge treatment device obtained by the mass balance monitoring means, sludge concentration rate in the solid-liquid separation means, property change of the activated sludge detected by the sludge property sensor and the dehydration Control means for controlling the agglomeration reaction processing apparatus for increasing / decreasing the COD component by increasing / decreasing the drug injection amount, changing the concentration of the chemical solution, or changing the brand of the chemical solution from the surplus processing capacity of the dehydrator detected by the functional force monitoring means, and / or Alternatively, a raw water bypass control means for bypassing part or all of the raw water flowing into the agglomeration reaction treatment device to the activated sludge treatment device and / or an activated sludge treatment device by controlling the amount of excess sludge withdrawn from the activated sludge treatment device MLSS concentration adjusting means for adjusting the MLSS concentration of
Adjusting the load of the activated sludge treatment device by at least one of the control means for controlling the agglomeration reaction treatment apparatus, the raw water bypass treatment control means, and the MLSS concentration adjusting means to make the activated sludge have a preferable property. It is a feature.

Therefore, the operation management method of the above-described wastewater treatment plant can manage the concentration of impurities in the raw water flowing into the activated sludge treatment apparatus within the range not exceeding the surplus capacity of the dehydrator, and can set the management target of the coagulation treatment.
Preferably, the operation management method of the wastewater treatment plant described above further includes a diffused surplus capacity detecting means for detecting surplus capacity of the diffuser in the activated sludge treatment apparatus, and detecting the power consumed by the diffuser and Power consumption detection means for determining the power consumption efficiency of the air device,
The control means for controlling the agglomeration reaction processing apparatus is a medicine injection from the surplus capacity of the aeration apparatus detected by the aeration surplus capacity detection means and the power consumption efficiency of the aeration apparatus determined by the power consumption detection means. The COD component is increased or decreased by increasing or decreasing the amount, changing the concentration of the chemical, or changing the brand of the chemical.

Therefore, the operation management method of the above-mentioned wastewater treatment plant monitors the power consumption of the air diffuser, evaluates the power margin efficiency (margin capacity) by quantifying the power consumption efficiency, and thereby the activated sludge in the aeration tank. It can be determined whether or not the organic load can be further applied from the present time, and the target management of the coagulation treatment or the raw water inflow restriction management can be performed.
Here, the preferable property means that the sludge is in a normal state that is neither dispersed nor dismantled.

According to the operation management method for a wastewater treatment plant according to claims 1 to 4 of the present invention, the COD component increase / decrease process by the control means for controlling the coagulation reaction treatment apparatus and / or the raw water bypass process control by the raw water inflow means. Since the activated sludge is controlled to have a preferable property, the amount of organic matter flowing into the activated sludge treatment apparatus is adjusted to optimize the BOD sludge load, thereby improving the preferable property from the dispersed state or the dismantled state of the activated sludge. Can be recovered.

Moreover, since the operation management method of the above-mentioned wastewater treatment plant calculates | requires the activated sludge increase / decrease amount per time of system sludge, the standard of the excess sludge extraction amount per hour or per day is known. Moreover, it is possible to control the adjustment with the excess sludge extraction amount so that the MLSS concentration in the aeration tank becomes a target value.
On the other hand, the operation management method of the wastewater treatment plant controls the concentration of impurities in the activated sludge inflow raw water within the range not exceeding the excess capacity of the dehydrator because the surplus capacity of the dehydrator is numerically controlled. It is possible to set management goals.

  Or, since the operation management method of the above-mentioned wastewater treatment plant monitors the power consumption of the air diffuser and digitizes the power consumption efficiency to evaluate the margin (capacity) of the plant, the activated sludge is loaded with organic matter. It is possible to determine whether or not it is possible to perform the target management of the coagulation treatment or the raw water inflow restriction management.

  Hereinafter, an operation management method for a wastewater treatment plant according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram showing an example of a wastewater treatment plant to which the operation management method for a wastewater treatment plant of the present invention is applied. In this figure, reference numeral 1 denotes a coagulation reaction treatment tank that receives raw water to be drained and is agitated with the injected coagulant to cause a coagulation reaction with a suspension contained in the raw water. The raw water stirred with the coagulant in the coagulation reaction treatment tank 1 is sent to the coagulation sedimentation tank 2 (in the present invention, the coagulation reaction treatment tank and the coagulation precipitation tank are referred to as an aggregation reaction treatment apparatus). Suspension produced by the coagulation reaction is precipitated below the coagulation sedimentation tank 2, while supernatant water is obtained above the coagulation sedimentation tank 2. The supernatant water is sent to a reservoir tank 3 that is temporarily stored to be sent to a subsequent processing step.

The raw water held in the reservoir tank 3 is sent by the pump 4 to the aeration tank 5 of the next activated sludge treatment apparatus. An aeration tube 5a is provided at the bottom of the aeration tank 5, and air is fed by the blower 5b. This aeration tank 5 holds activated sludge, and organic substances contained in the raw water are decomposed into H ₂ O and CO ₂ by the chemical activity of the activated sludge. Next, the mixed solution is sent to a sedimentation basin 6 as a solid-liquid separation means for the next stage for separating into supernatant water and sludge. The supernatant water of the sedimentation basin 6 is drained as treated water, while the sludge accumulated below the sedimentation basin 6 is discharged from the sedimentation basin 6 by the pump 6a, and a part thereof is sent back to the aeration tank 5 as return sludge. The remainder is taken out of the system as excess sludge.

Further, between the agglomeration reaction treatment tank 1 and the aeration tank 5, a bypass valve 9 a for bypassing a part of the raw water input to the agglomeration reaction treatment tank 1 in accordance with a command from the plant controller 10 described later, to the aeration tank 5, A bypass pipe 9b and a flow path opening / closing valve 9c are provided.
The sediment from the coagulation sedimentation tank 2 and the excess sludge from the sedimentation basin 6 are mixed with a polymer dehydrating agent, and the water contained in each is dehydrated by the dehydrator 7 to form a dehydrated cake.

  The aeration tank 5 is provided with a sludge property sensor 8 for detecting the property of activated sludge in the tank. This sludge property sensor 8 is, for example, a sludge property sensor described in Japanese Patent Application No. 2005-23091, and the activity in the measuring tank 8a that accommodates the measured sludge pumped up by the sludge sampling pump 8b from the aeration tank 5. It is positioned immediately below the water surface of the sludge slurry and outputs a detection signal corresponding to the concentration and particle diameter of the activated sludge slurry. The detection signal output by the sludge property sensor 8 is detected by the time-dependent change detecting means 10a for capturing the time-dependent change in concentration and particle diameter when the activated sludge slurry is naturally settled in the measuring tank 8a, and the time-dependent change detecting means. The sludge property determining means 10b for determining the property of the activated sludge contained in the activated sludge slurry from the secular change of the concentration and particle diameter of the captured activated sludge slurry, and the property of the activated sludge determined by the sludge property determining means 10b in the plant. It is given to the plant control apparatus 10 provided with the control part 10c which controls a sludge property to a preferable property.

  As shown in FIG. 2, the control unit 10c performs an increase / decrease process of the COD component by increasing / decreasing the chemical injection amount, changing the concentration of the chemical solution, or changing the brand name of the chemical solution from the property of the activated sludge detected by the sludge property sensor 8. Agglomeration reaction processing device control means 100 for controlling the raw water, raw water bypass control means 101 for bypassing part or all of the raw water flowing into the agglomeration reaction treatment tank 1 to the aeration tank 5, surplus transferred from the settling tank 6 to the dehydrator 7 MLSS concentration adjusting means 102 for adjusting the MLSS concentration in the aeration tank 5 by controlling the amount of sludge withdrawn, mass balance monitoring for determining the increase / decrease amount of activated sludge per hour in the wastewater treatment plant system and the sludge concentration rate in the settling basin 6 Means 103, dehydrating function monitoring means 104 for detecting surplus treatment capacity in the dewatering of sludge processed by the dehydrator 7, aeration equipment in the aeration tank 5 Diffuse surplus capacity detection means 105 for detecting the surplus capacity of power, power consumption detection means 106 for detecting the power consumed by the air diffuser and determining the power consumption efficiency of the air diffuser, and waste water detected by the mass balance monitoring means 103 Increase / decrease amount of sludge per hour in the treatment system, sludge concentration rate in the sedimentation basin 6, property change of activated sludge detected by the sludge property sensor 8, surplus treatment capacity of the dehydrator detected by the dewatering functional force monitoring means 104 From the surplus capacity of the air diffuser detected by the air diffuser surplus capacity detecting means 105 and the power consumption efficiency of the air diffuser determined by the power consumption detecting means 106, the increase or decrease in the dose, the concentration change of the chemical liquid, or the brand of the chemical liquid Aggregation reaction process correction control means 107 for correcting the control of the agglutination reaction processing apparatus capable of controlling the COD component increase / decrease process by the change is provided.

  The temporal change detection means 10a detects the temporal change of the activated sludge in which the activated sludge slurry in the measuring tank 8a settles and accumulates from the detection data of the sludge property sensor 8. And the sludge property determination means 10b determines the property of the activated sludge contained in the activated sludge slurry from the change with time of the activated sludge detected by the change with time detection means 10a. Specifically, the sludge property determination is performed based on the flowchart shown in FIG.

The sludge property determination is described in, for example, Japanese Patent Application No. 2005-23091 described above as the sludge property sensor 8 when the activated sludge slurry accommodated in the measuring tank 8a is stirred uniformly by a predetermined means or immediately after stirring. Using the detection signal output from the sludge property sensor (scattered light sensor), the initial concentration information S ₀ and the initial particle size information N ₀ of the activated sludge slurry are detected [step S100]. Then, the sludge quality determining unit 10b determines the properties of the activated sludge contained in the activated sludge slurry by receiving such information, the initial concentration information S ₀ determines whether less than a predetermined density level C ₁ [Step S101] . At this time, the sludge property determination means 10b determines that the concentration of the activated sludge slurry is outside the measurement range when it is determined that [C ₁ > S ₀ ] [step S102]. That is, the sludge property determining means 10b determines that the dilution is poor.

On the other hand, when the sludge property determining means 10b determines that [C ₁ ≧ S ₀ ] in step S101, the time-dependent change detecting means 10a is measured from the detection signal output from the sludge property sensor 8 after a predetermined time has elapsed. detecting the density information _{S t} and particle size information _{N t} of the activated sludge slurry in the 8a [step S103]. Then aging detection means 10a, while obtaining a difference between the initial density information _{S 0} and density information _{S t} after a predetermined time _[S 0 -S _t], the sludge property determining unit 10b, the concentration this value is given It is checked whether it is greater than level C ₂ (where C ₂ > C ₁ ) [step S104].

Sludge quality determining unit 10b in step S104, when it is determined that the predetermined concentrations greater than the level _{C 2,} further difference between the initial density information _{S 0} from the predetermined time has elapsed after the density information _{S t [S} 0 -S _t] is It is checked whether or not there is a predetermined density level C ₃ (where C ₃ > C ₂ ) or more [step S105]. Sludge quality determining unit 10b, when it is determined that the predetermined density level C ₃ or higher in step S105, determines that the activated sludge contained in the activated sludge slurry in preferred properties [Step S106].

On the other hand, the sludge quality determining unit 10b in step S104, determines a difference from the initial concentration information _{S 0} and density information _{S t} after a predetermined time _[S 0 -S _t] is to be the predetermined concentration level _{C 2} or less Further, a difference [N ₀ −N _t ] between the initial particle size information N ₀ detected in step S100 and the particle size information N _t detected in step S103 is obtained, and whether or not the obtained value is 0 or more is determined. Check [Step S8]. Next, when it is determined in step S107 that [N ₀ −N _t ] is _equal to or greater than ₀ , the sludge property determination means 10b further determines whether the initial particle size information N ₀ is equal to or less than the predetermined particle size C ₄ [ Step S108] When it is determined that [N ₀ ≦ C ₄ ], it is determined that the property of the activated sludge contained in the activated sludge slurry is dispersed sludge [Step S109].

On the other hand, the sludge property determining means 10b in step S107, dirt scattered light sensor when the difference _[N 0 -N _t] is less than 0 and particle size information _{N t} detected in step S4, algae, sludge mass, It is determined that other foreign matter such as solid matter has adhered [step S110].
Also, sludge quality determining unit 10b in step S108, when the initial particle size information N ₀ is determined to be less than the predetermined particle diameter C _4, the occurrence of filamentous bulking or mucilaginous bulking activated sludge slurry, other It is determined that an abnormality has occurred [step S111].

On the other hand, the sludge property determining unit 10b, in step S105, the difference between the periods density information _{S 0} from the predetermined time has elapsed after the density information _{S t [S} 0 -S _t] is to be the predetermined concentration level _{C 3} or less determined Then, a difference [N ₀ −N _t ] between the initial particle diameter information N ₀ detected in step S1 and the particle diameter information N _t detected in step S103 is further determined, and whether or not the calculated value is 0 or more. [Step S112]. The sludge property determining means 10b determines that the property of the activated sludge contained in the activated sludge slurry is dismantled sludge when it is determined in this step S112 that [N ₀ -N _t ] is 0 or more [step S113]. On the other hand, when it is determined that [N ₀ −N _t ] is less than 0, it is determined that foreign matter such as bubbles adheres to the sludge property sensor 8 and measurement is impossible [step S114].

  By the way, sludge in a dispersed state has a low terminal sedimentation speed because of its small particle size, and therefore, even if it is naturally settled, a sludge accumulation layer is not formed, and a boundary between the accumulation layer and the water layer does not appear. On the other hand, sludge in a dismantled state has a sludge group with a large particle diameter having floc-forming power contained in the activated sludge slurry. For this reason, when the activated sludge slurry containing this dismantled sludge is stirred uniformly in a container and then allowed to stand, for example, the sludge settles and accumulates at the bottom of the container with the passage of time, forming a sludge accumulation layer, Small particles generated by dismantling cannot settle, and the water layer that should become the supernatant water becomes turbid. On the other hand, the activated sludge having a preferable property is obtained by uniformly stirring the activated sludge slurry contained in a predetermined container and then leaving it for a predetermined time, so that the activated sludge slurry in the container is separated into a deposited layer and a supernatant water.

Now, the operation management method of the wastewater treatment plant according to the first embodiment of the present invention using such a plant control device 10 is characterized by the properties of the activated sludge in the activated sludge process (dispersed sludge, demolition sludge). Or normal sludge) is numerically evaluated.
Specifically, in the case of dispersed sludge, it is necessary to optimize the agglomeration reaction in the agglomeration reaction treatment tank 1 and to minimize the bringing of organic substances into the activated sludge in the aeration tank 5. For this reason, what is necessary is just to change the chemical | drug | medicine amount of the flocculant to the aggregation reaction processing tank 1, or to reselect a chemical | medical agent brand, and to change into an effective thing.

  First, in order to increase the amount of drug injection, the discharge amount of the drug injection pump P1 may be increased or the drug concentration may be increased. In addition, if there is a change in the substrate (organic component) in the raw water, a jar test is performed to select and change an effective drug. Then, the adjustment is continued until the activated sludge output from the plant control device 10 has a preferable property (normal sludge), and the dosage of the flocculant and the chemical brand that optimize the flocculation reaction in the flocculation reaction treatment tank 1 are selected, This is set as a new operating condition.

On the other hand, in the case of demolition sludge, a part or all of the raw water is temporarily directly introduced into the aeration tank 5 without going through the agglomeration reaction treatment tank 1.
Alternatively, particularly when an organic substance adsorbing substance (COD reducing agent) is used alone or in combination as a flocculant, this addition amount is temporarily stopped or the addition amount is reduced to increase the organic concentration of the agglomerated water. , Flow into the aeration tank 5. And adjustment is continued until the activated sludge which the plant control apparatus 10 outputs becomes a preferable property. Thus, the addition amount of the flocculant when the activated sludge becomes preferable properties and the raw water bypass amount to the aeration tank 5 are set as new operating conditions.

  In addition, when the above-mentioned operation is carried out, if the effect does not appear even after ½ time of sludge SRT has elapsed, the bypass valve 9a is opened, and the raw water is supplied to the aeration tank 5 via the bypass pipe 9b. The process of increasing the bypass amount and / or the process of reducing the addition amount of the flocculant by controlling the driving of the chemical injection pump P1 is studied, and the adjustment is repeated until the activated sludge output from the plant control device 10 has a favorable property.

  Thus, according to the operation management method of the wastewater treatment plant according to the first embodiment of the present invention, when the sludge is in a dispersed state by the above-described operation, the flocculant chemical injection that optimizes the flocculation reaction in the flocculation reaction treatment tank 1 is performed. While the amount and drug brand are selected, when in the dismantled state, the amount of organic substances flowing into the aeration tank 5 is adjusted by controlling the amount of flocculant added and the amount of raw water bypass to the aeration tank 5 to reduce the BOD sludge load. Since it is optimized, it is possible to recover the activated sludge from a dispersed state or a disassembled state to a preferable property.

Next, the operation management method for the wastewater treatment plant according to the second embodiment of the present invention will be described. This embodiment is different from the first embodiment described above in that the control of the excess sludge extraction amount is taken into consideration in addition to the first embodiment.
First, in the case of dispersed sludge, as described above, the chemical injection amount in the coagulation reaction process may be increased, or the excess sludge extraction amount may be reduced. That is, in the agglomeration reaction process, the amount of chemical injection is increased to optimize the agglomeration reaction, to minimize the amount of organic matter brought into the aeration tank 5, to reduce the excess sludge extraction amount, and to increase the MLSS concentration in the aeration tank 5. If the control is performed so as to increase the BOD sludge load and maintain the preferable properties of the activated sludge, the operation management of the appropriate wastewater treatment plant can be performed.

  However, while the increase in the amount of chemical injection in the above-described agglomeration reaction treatment is immediate, the adjustment of the MLSS concentration by reducing the excess sludge extraction amount takes time until the optimum condition is reached. Therefore, the amount of chemical injection in the coagulation reaction treatment is first increased to improve the sludge, and then adjusted so as to reduce the excess sludge extraction amount. Then, finally, adjustment and control for reducing the amount of excess sludge withdrawing may be repeated until the activated sludge output from the plant control device 10 has favorable properties.

Next, in the case of dismantled sludge, the amount of flocculant added is reduced, or the chemical solution is temporarily stopped to increase the organic matter concentration of the agglomerated treated water and flow into the aeration tank 5, so that part or all of the raw water If it is made to flow directly into the aeration tank 5, operation management of an appropriate waste water treatment plant can be performed.
As a specific example of this method, when the raw water BOD of the agglomeration reaction treatment tank 1 at the design stage is 10000 mg / L and the treated water BOD of the agglomeration reaction treatment tank 1 is 1000 mg / L, as shown below Control is performed.

First, as a control of the amount of raw water flowing into the agglomeration reaction treatment tank 1, for example, 1/10 of the total amount of raw water is directly introduced into the aeration tank, while the remaining raw water (9/10) is passed through the agglomeration reaction treatment tank 1, Is allowed to flow into the aeration tank 5 (continuous for 24 hours). Then the original load is
1000 [kg / m ³ ] × y [m ³ / day]
However, the load applied in this embodiment is
10000 [kg / m ³ ] × 1/10 y [m ³ / day]
+1000 [kg / m ³ ] × 9/10 y [m ³ / day]
= 1900 [kg / m ³ ] × y [m ³ / day]
It becomes. That is, a load 1.9 times that before the countermeasure can be applied.

Next, 1 times the amount of raw water is allowed to flow directly into the aeration tank 5 for 1 hour. Then, for the remaining 23 hours, the treated water in the agglomeration reaction treatment tank 1 is caused to flow into the aeration tank 5. Then the original load is
1000 [kg / m ³ ] × y [m ³ / day]
However, the load applied in this embodiment is
10,000 [kg / m ³ ] × 1 / 24y [m ³ / day]
+1000 [kg / m ³ ] × 23 / 24y [m ³ / day]
= 1750 [kg / m ³ ] × y [m ³ / day]
It becomes. That is, a load 1.75 times before the countermeasure can be applied.

Next, control of the agglomeration reaction treatment tank 1 will be described. This control is to reduce the amount of the flocculant added or intermittently stop the supply of the chemical solution to increase the organic matter concentration of the agglomerated treated water and flow it into the aeration tank 5. Further, the plant control device 10 increases the excess sludge extraction amount to reduce the MLSS concentration in the aeration tank 5 and increases the BOD sludge load to control the optimum value.
Alternatively, the plant control device 10 controls the driving of the above-described chemical injection pump P1 to increase the amount of chemical injection to be introduced into the agglomeration reaction processing tank 1, or increase the amount of bypass to the raw water aeration tank 5 through the bypass pipe 9b. The adjustment is repeated until the activated sludge has favorable properties by performing at least one control among the treatment to be performed and the increase of the excess sludge extraction amount.

Next, the plant control device 10 optimizes the chemical injection amount in the agglomeration reaction treatment tank 1 to return the processing to normal, and controls the increase in the excess sludge extraction amount while monitoring the properties of the activated sludge output by the plant control device 10. Subsequently, the MLSS concentration is optimized.
The operation management method of the wastewater treatment plant according to the second embodiment specifically described above is performed according to the procedure of the flowcharts shown in FIGS. 3 and 4. This is an example of the operation management method of the wastewater treatment plant using the measurement result of the sludge property sensor 8 described above.

  In the operation management method of the wastewater treatment plant, the activated sludge property is determined from the detection result of the sludge property sensor 8 provided in the plant control device 10 of the drainage plant to which the operation management method is applied [step S1]. This property determination of activated sludge determines whether the property of activated sludge is normal sludge, dispersed sludge, or dismantled sludge as described above. If the property of the activated sludge is neither dispersed sludge nor dismantled sludge in step S1, the plant control device 10 does not perform subsequent processing as normal sludge.

  Next, when it is determined in step S1 that the activated sludge is a dispersed sludge, the plant control device 10 detects the activated sludge properties output by the sludge sensor with a predetermined level (for example, five-step evaluation). Data is digitized [step S2]. In this predetermined leveling, for example, [5] is set as the level indicating the properties of activated sludge requiring urgent action as the sludge is dispersed, and [1] is set as the state of the lightly dispersed sludge. Next, the plant control device 10 determines the presence or absence of the urgency of the process from the level indicating the property of the activated sludge that has been digitized [Step S3]. In step S3, when the control device determines that the detection data leveled in step S2 is [5] and it is necessary to respond urgently, the dosage of the flocculant injected into the agglutination reaction processing tank 1 is determined. Is increased [Step S4], and the surplus amount of activated sludge is reduced [Step S5].

  And the plant control apparatus 10 performs the property determination of activated sludge from the detection result of the sludge property sensor 8 [step S6]. When the plant control apparatus 10 determines in step S6 that the properties of the activated sludge are poor (the level indicating the properties of the activated sludge is 3 or more, for example), the plant control device 10 returns to step S5 again to reduce the excess sludge extraction amount. Moreover, when the plant control apparatus 10 determines in step S6 that the activity property is abnormally bad (the level indicating the activity property is 4 or more, for example), the amount of raw water flowing into the agglomeration reaction treatment tank 1 is temporarily reduced. [Step S7]. Next, in order to see the effect of step S7, the property of activated sludge is determined [step S8]. When there is an effect, the process returns to step S5 again to reduce the excess extraction amount of the activated sludge. On the other hand, when the effect is not seen, the amount of raw water is further reduced again. When the plant control apparatus 10 determines in step S6 that the activated sludge has favorable properties, it registers the current amount of flocculant and the amount of excess sludge withdrawn as new operation management values [step S9].

  On the other hand, when the plant control apparatus 10 determines in step S3 that there is no need to respond urgently (the level indicating the property of the activated sludge is 4 or less, for example), the plant control apparatus 10 reduces the excess sludge extraction amount [step S10]. And the plant control apparatus 10 performs the property determination of activated sludge from the detection result of the sludge property sensor 8 [step S11]. When the plant control apparatus 10 determines in step S11 that there is an effect of reducing the excess sludge extraction amount in step S10, the plant control apparatus 10 returns to step S10 again and proceeds with reduction of the excess sludge extraction amount. On the other hand, when the plant control apparatus 10 determines that there is no effect as a result of the property determination of the activated sludge in step S11, the plant control apparatus 10 increases the amount of the flocculant injected into the agglomeration reaction treatment tank 1 [step S12]. . In addition, when the plant control apparatus 10 determines that the property of the activated sludge has been improved as a result of the property determination of the activated sludge in step S11 (the level indicating the property of the activated sludge is, for example, 2 or less), the current flocculant Are registered as new operation control values [Step S9].

  On the other hand, when the plant control apparatus 10 determines the property of activated sludge in step S1 and determines that it is dismantled sludge, the plant controller 10 assigns a predetermined level to the property of the activated sludge output by the sludge sensor (for example, five-step evaluation). Then, the detected data is digitized [step S20]. In this predetermined leveling, for example, [5] is the level indicating the properties of activated sludge that requires urgent action as sludge disintegration progresses, and [1] is the state of lightly dismantled sludge. Next, the plant control device 10 determines the presence or absence of the urgency of the process from the value obtained by quantifying and leveling the properties of the activated sludge [Step S21]. In step S21, when the plant control apparatus 10 determines that the detection data leveled in step S20 is [5] and needs to be dealt with urgently, part of the raw water flowing into the agglomeration reaction treatment tank 1 Is introduced into the aeration tank 5 [Step S22], and the amount of the flocculant added to the agglomeration reaction treatment tank 1 is reduced, or the chemical liquid supply is intermittently stopped to reduce the amount of chemical injection [Step S23]. Then, the excess sludge extraction amount of the activated sludge is increased [step S24].

  And the plant control apparatus 10 performs the property determination of activated sludge from the detection result of the sludge property sensor 8 [step S25]. When the control device determines in step S25 that the activated sludge has poor properties (the level indicating the activated sludge properties is, for example, 3 or more), the control device returns to step S24 again to increase the excess sludge extraction amount. Moreover, when the plant control apparatus 10 determines in step S25 that the property of the activated sludge is abnormally bad (the level indicating the property of the activated sludge is 4 or more, for example), the process returns to step S22 or step S23, and enters the agglomeration reaction treatment tank 1. A part of the inflowing raw water is allowed to flow into the aeration tank 5 [Step S22], and the amount of the flocculant injected into the agglomeration reaction treatment tank 1 is further reduced [Step S23], and the excess sludge extraction amount is further increased. [Step S24], and then the activated sludge property determination is repeated again in step S25. In addition, when the plant control apparatus 10 determines in step S25 that the properties of the activated sludge are improved (the level indicating the properties of the activated sludge is, for example, 2 or less), the current amount of the flocculant, the excess sludge extraction amount, and The raw water bypass amount to the aeration tank 5 is registered as a new operation management value [step S26].

  On the other hand, when the plant control apparatus 10 determines in step S21 that there is no need to respond urgently, the plant control apparatus 10 increases the excess sludge extraction amount [step S27]. And the plant control apparatus 10 performs the property determination of activated sludge from the detection result of the sludge property sensor 8 [step S28]. When the plant control apparatus 10 determines in step S28 that there is an effect of increasing the excess sludge extraction amount in step S27, the process returns to step S27 again to further increase the excess sludge extraction amount. On the other hand, as a result of determining the property of the activated sludge in step S28, the control device bypasses a part of the raw water flowing into the agglomeration reaction treatment tank 1 and flows it into the aeration tank 5 [ Along with [Step S29], the dosage of the flocculant charged into the agglomeration reaction treatment tank 1 is reduced [Step S30]. And it returns to step S28 again, and a control apparatus performs the property determination of activated sludge from the detection result of the sludge property sensor 8. FIG.

When the plant control apparatus 10 determines in step S28 that the properties of the activated sludge have improved, the new operation control value is used for the current amount of the flocculant, the amount of excess sludge withdrawn, and the amount of raw water bypass to the aeration tank 5. [Step S26].
On the other hand, when the plant control device 10 suddenly determines in step S21 that the generation of demolition sludge has been detected, it is assumed that the raw water is mixed with poisons, alkalis, acids, high-temperature water, etc., and there is some abnormality in the raw water. The raw water flowing into 5 is stopped [step S31].

Thus, the operation management method for the wastewater treatment plant according to the second embodiment of the present invention adjusts the amount of organic matter flowing into the aeration tank 5 and optimizes the BOD sludge load by the operation of the plant control device 10 described above. Thus, recovery from the dispersed state or the dismantled state of the activated sludge can be achieved.
Next, an operation management method for a wastewater treatment plant according to a third embodiment of the present invention will be described. This third embodiment differs from the above-described embodiment in that the amount of increase / decrease of sludge in the system per time and the sludge concentration rate in the sedimentation basin 6 as solid-liquid separation means are quantified by mass balance monitoring. is there.

  In this mass balance monitoring, the amount of increase / decrease of sludge in the system per hour and the concentration rate in the settling basin 6 are quantified by calculation described later. In this mass balance monitoring, as shown in FIG. 5, the amount of sludge increased / decreased in the aeration tank per predetermined time is A, the amount of sludge increased / decreased in the settling tank 6 per predetermined time is B, and discharged outside the system per predetermined time. If the amount of sludge is C, the amount of increase / decrease in the system sludge per predetermined time can be obtained by [A + B + C]. Here, A, B, and C described above can be defined as shown in the following equations, respectively.

A = (X _{F present-} X _{Fk hours ago} ) x V
B = Σ {X _F × (Q _I + Q _R ) −X _R × Q _B } / k
However, Σ is the total from k hours ago to the present C = Σ (X _F × Q _T ) / k
However, the sum of up to Σ is k times before-present _{also, X} F: MLSS concentration X _{F Current} aeration tank: MLSS concentration of the current aeration tank X _{Fk time ago:} k MLSS concentration time previous aeration tank X _R: MLSS concentration of return sludge Q _I : Raw water flow rate of inflow into aeration tank Q _R : Return flow rate of sludge returned to aeration tank Q _T : Excess sludge discharge flow rate Q _B : Sludge flow rate withdrawn from sedimentation tank (Q _B = Q _R + Q _T )
Moreover, the sludge concentration rate in the settling basin 6 is defined as [(Q _B × X _R ) / (Q _I × X _F )] from the above-described values. Then, the plant control apparatus 10 is preferable from the dispersion state of activated sludge if the same control as in the second embodiment described above is performed to adjust the amount of organic matter flowing into the aeration tank 5 and the BOD sludge load is optimized. Recovery can be achieved.

However, since the amount of increase / decrease of the sludge in the system per predetermined time is obtained by the above calculation unlike the second embodiment described above, the third embodiment can also obtain an indication of the amount of excess sludge withdrawn. Further, the flow rate of the raw water flowing into the aeration tank can be determined from the obtained sludge concentration rate so that the sludge interface in the sedimentation basin 6 does not rise.
The sludge retention time (current SRT) can be obtained by applying the above-described equation to the amount of surplus sludge withdrawn in an increased or decreased amount per predetermined time. Incidentally, the current SRT is [(sludge retention amount in the system) / (sludge amount per 24 hours discharged from the system)].

  The amount of sludge retained in the system is the amount of sludge present in the aeration tank 5, the amount of accumulated sludge in the settling basin 6, the amount of sludge retained in the sludge intermediate storage tank (not shown), and the piping connecting the tanks. This is the total amount of sludge present inside. Alternatively, the amount of sludge retained in the system may be approximated as the amount of sludge present in the aeration tank 5. In this case, the amount of sludge present in the aeration tank 5 can be obtained as the product of the MLSS concentration in the aeration tank 5 and the volume of the aeration tank 5.

  If managed in this way, the excess sludge extraction amount can be managed based on the SRT, and the SRT reference value (usually 5 to 30 days, but preferably 7 to 14 days) is set, and the current SRT is set. And the surplus sludge extraction amount can be determined so that the reference value of SRT becomes equal. That is, the excess sludge extraction amount is obtained as a value obtained by dividing the sludge retention amount in the system by the SRT reference value.

Moreover, the target value of the MLSS concentration of the aeration tank 5 can be determined using this SRT as an index. Specifically, the target value of the MLSS concentration in the aeration tank 5 can be obtained as [standard value of SRT × sludge amount increased / decreased per 24 hours in the system / aeration tank volume].
The operation management procedure of the wastewater treatment plant using the optimum value of the MLSS concentration of the aeration tank 5 obtained as described above will be described with reference to FIGS. 6 and 3. FIG. 6 shows a flowchart for performing control by determining the surplus capacity of the aeration tank 5 in addition to the processing procedure similar to the operation management method of the wastewater treatment plant shown in FIG. 3 described above, and is the same as FIG. These processes are denoted by the same reference numerals, and the description thereof is omitted.

  First, the plant control apparatus 10 calculates the optimum value of the MLSS concentration in the aeration tank 5 as described above [Step S40]. Next, the plant control device 10 determines the surplus capacity of the solid-liquid separation of the settling tank 6 [Step S41]. When it is determined in step S41 that the sedimentation basin 6 has surplus capacity for solid-liquid separation, the plant control apparatus 10 outputs a surplus sludge extraction amount increase command related to the processing in step S24 or step S27. On the other hand, when it determines with the plant control apparatus 10 having no surplus capacity in the sedimentation basin 6 by step S41, the raw | natural water flow rate which flows in into the aeration tank 5 is reduced temporarily. Thus, the plant control device 10 quickly makes the activated sludge have preferable properties.

Thus, in the operation management method of the wastewater treatment plant according to the third embodiment of the present invention, the surplus sludge extraction amount and the MLSS of the aeration tank 5 are set so as to be the target value of the MLSS concentration of the aeration tank 5 calculated as described above. Since the concentration adjustment is controlled, it is possible to manage the operation to maintain the activated sludge in a desirable property.
Next, an operation management method for a wastewater treatment plant according to a fourth embodiment of the present invention will be described. The fourth embodiment is different from the above-described embodiment in that 1D-flux theory is applied.

Prior to applying the 1D-flux theory, the limit value of the device design is Q _Imax1 , and the limit value determined by the sedimentation basin sludge concentration and sludge settling index is Q _Imax2 . Q _Imax1 is defined as the product of the design value of the sedimentation basin area load and the water area of the sedimentation basin. However, the design value of the water area load is normally 5 to 10 [m / h]. On the other hand, Q _Imax2 is defined as the product of the sludge sedimentation rate based on the 1D-flux theory and the water area of the sedimentation basin. The sedimentation basin sludge concentration is the MLSS concentration in the aeration tank 5 and the sludge statically settled by gravity. It is determined from sludge sedimentation indices such as SV30, diluted SV30 (DSV30), and stirred SV30 (SSV30).

Then, the sludge settling velocity according to the 1D-flux theory (Daiger's approximate expression) can be defined as [V ₀ e ^−nX ].
However,
V ₀ : Terminal sedimentation velocity of sludge [m / h]
n = 0.103 + 0.002555 × DSVI
DSVI = Initial sludge concentration at DSV30 / DSV30 measurement X = Sludge concentration at the part related to solid-liquid separation = Sludge concentration around the sedimentation basin feedwell or sludge concentration at the top of the sludge accumulation layer ≒ MLSS concentration in the aeration tank [N] represents an approximate expression using DSVI, but an approximate expression using SVI or SSVI may be applied.

According to these formulas, the solid-liquid separation performance in the sedimentation basin 6 can be evaluated.
The operation management procedure of the wastewater treatment plant using the optimum value of the MLSS concentration of the aeration tank 5 obtained as described above is the same as the procedure of the wastewater treatment plant shown in FIG. 3 showing the control flow of the second embodiment described above. And the activated sludge is controlled so as to quickly have favorable properties.
Thus, the operation management method of the wastewater treatment plant according to the fourth embodiment of the present invention can obtain the management index of the MLSS concentration of the aeration tank 5 by performing the above-described calculation, and the obtained value as the control target value. Since it is set, the operation management of the wastewater treatment plant maintaining the preferable properties of the activated sludge can be performed.

Next, an operation management method for a wastewater treatment plant according to a fifth embodiment of the present invention will be described. This fifth embodiment is different from the above-described embodiment in that the surplus capacity evaluation of the dehydrator 7 is taken into consideration.
The surplus capacity of the dehydrator 7 is evaluated by first obtaining the current capacity of the dehydrator 7 as a value obtained by dividing the amount of sludge applied to the dehydrator by the operating time of the dehydrator, and then the amount of sludge applied to the dehydrator 7 It is determined as the sum of the amount of sludge discharged from activated sludge per 24 hours, the amount of sludge discharged from the agglomeration reaction treatment tank 1 per 24 hours, and the amount of sludge flowing in every other 24 hours. And the surplus capacity of the dehydrator 7 is defined as the difference between the limit capacity of the dehydrator and the amount of sludge to be dewatered. Then, the limit capacity of the dehydrator 7 can be obtained as [current capacity of dehydrator × (24 / current operation time of dehydrator)].

  Here, the surplus capacity of the dehydrator 7 is determined as a value obtained by dividing the surplus capacity of the dehydrator by the limit capacity of the dehydrator, and the surplus capacity rate of the dehydrator 7 is defined as surplus capacity of the dehydrator × 100 [%]. For example, the surplus capacity of the dehydrator 7 can be evaluated. Then, the plant control apparatus 10 may be managed so that the excess capacity of the dehydrator that can be obtained using the above-described formula does not exceed [1] or the excess capacity rate of the dehydrator. If the excess capacity of the dehydrator exceeds [1] or the excess capacity rate of the dehydrator exceeds [100%], the sludge growth in the aeration tank 5 may be suppressed.

  The operation management procedure of the wastewater treatment plant using the surplus capacity evaluation value of the dehydrator 7 obtained as described above will be described with reference to FIGS. This figure shows a flowchart for determining and controlling the surplus capacity of the dehydrator 7 in addition to the processes similar to those in FIGS. 3 and 4 showing the processing procedure of the second embodiment described above. 3 and 4 are denoted by the same reference numerals, and the description thereof is omitted.

  First, the plant control apparatus 10 calculates the surplus capacity of the dehydrator 7 as described above [step S50]. Next, the plant control device 10 determines whether or not the processing of the dehydrator 7 has surplus capacity [step S51]. The plant control apparatus 10 that has determined that there is no surplus capacity in the processing of the dehydrator 7 in step S51 further outputs an increase command for the dosage of the flocculant related to the processing in step S4 or step S12. Alternatively, the plant control apparatus 10 that has determined that the processing of the dehydrator 7 has surplus capacity in step S51 subsequently calculates the optimum value of the MLSS concentration [step S40]. Next, when it is determined through step S41 that determines the surplus capacity for solid-liquid separation in the sedimentation tank 6 that the sedimentation tank 6 has surplus capacity for solid-liquid separation, the amount of surplus sludge withdrawn according to step S24 or step S27. A command to increase is output. Thus, the plant control apparatus 10 controls the activated sludge so as to quickly obtain a preferable property.

  Thus, since the operation management method of the wastewater treatment plant according to the fifth embodiment of the present invention performs the above-described calculation, the management target of the aggregation treatment can be set to be suitable for the wastewater treatment plant. Furthermore, in order to stabilize activated sludge, if the above-described calculation is performed, the MLSS concentration of the aeration tank 5 according to the raw water can be set, and while confirming the detection result of the plant control device 10 with the set result, It is possible to determine whether the raw water flow rate has increased, decreased or stopped by feeding back into the system.

Next, an operation management method for a wastewater treatment plant according to a sixth embodiment of the present invention will be described. The sixth embodiment is different from the above-described embodiment in that the surplus capacity evaluation of the aeration apparatus provided in the aeration tank 5 is taken into consideration.
Now, the air diffuser applied to the wastewater treatment plant can be divided into those by the blower 5b and those by surface agitation (not shown in FIG. 1).

First, when the diffuser is the blower 5b, the surplus capacity of the blower 5b can be obtained as a difference between the maximum capacity of the blower 5b and the current blower capacity.
Here, the blower capability is indicated by [BWe- ^kt ]. In this equation, B: reference value [m ³ / W] for the air consumption with respect to the electric power consumption, W: electric power consumption [W], k: temperature-dependent air blowing efficiency specific to the blower device, and t: temperature of the air to be blown. . If the surplus capacity of the blower 5b is used, the surplus capacity level of the blower 5b is obtained by dividing the surplus capacity of the blower 5b by the maximum capacity of the blower 5b, and the surplus capacity rate of the blower 5b is set to 100. It can be determined as a doubled value [%].

Incidentally, the theoretical oxygen dissolution value by the operation of the blower 5b can be obtained as [current blower capacity × e ^−βqt ] if the current blower capacity described above is used. In this formula, β: oxygen dissolution efficiency depending on the water quality such as salts, q: oxygen dissolution efficiency depending on the water temperature, and t: water temperature. Then, the oxygen amount (estimated value) utilized by the activated sludge can be obtained as a value obtained by subtracting [DO: current value of dissolved oxygen concentration measured by a meter] from the theoretical oxygen dissolution value by the operation of the diffuser. In this way, various quantities in the blower 5b can be determined.

Next, when the air diffuser is based on surface agitation, the surplus capacity of the surface agitation apparatus can be obtained as a difference between the maximum capacity of the agitator and the current agitation function power.
The stirring function force is defined as [CWe− ^αpt ]. In this equation, C: reference value [m ³ / W] of the stirrer for the power consumption, W: power consumption [W], α: slurry viscosity (or concentration) dependent watering efficiency peculiar to the stirrer, p : Temperature dependent watering efficiency specific to the stirrer, t: Temperature of water to be sprinkled.

If the surplus capacity of the surface agitator that can be obtained in this way is used, the surplus capacity of the surface agitator is obtained by dividing the surplus capacity of the agitator by the maximum capacity of the agitator, and the surplus capacity of the surface agitator. The rate can be defined as a value [%] obtained by multiplying the surplus capacity of the stirrer by 100.
Incidentally, the theoretical value of oxygen dissolution by the operation of the surface agitator can be obtained as [current agitation function force × e ^−βqt ] if the current agitation function force described above is used. Here, β: oxygen dissolution efficiency depending on the water quality such as salts, q: oxygen dissolution efficiency depending on the water temperature, and t: water temperature. Therefore, the oxygen amount (estimated value) utilized by the activated sludge can be obtained as a value obtained by subtracting [DO: the current value of dissolved oxygen concentration measured by a meter] from the theoretical oxygen dissolution value obtained by operating the diffuser.

If it defines in this way, various quantities in a surface stirring device can be defined. Therefore, the operation management of the wastewater treatment plant may be performed so that the excess capacity of the air diffuser does not exceed 1.
Further, the power consumption efficiency by the power consumption monitoring device of the air diffuser can be quantified as a value obtained by dividing the amount of oxygen used by the activated sludge by the theoretical value of oxygen dissolution by the operation of the air diffuser.
The operation management procedure of the wastewater treatment plant to which the surplus capacity evaluation of the air diffuser obtained as described above is applied will be described with reference to FIG. 9, FIG. 3, and FIG. These diagrams show a flowchart for performing control by determining the surplus capacity of the air diffuser in addition to the same processing as FIG. 3 and FIG. 4 showing the processing procedure of the second embodiment described above, The description of the same processing as in FIGS. 3 and 4 is omitted.

  First, the plant control device 10 calculates the surplus capacity of the air diffuser as described above [step S60]. Next, the plant control device 10 determines the surplus capacity of the diffuser [step S61]. When the plant control device 10 determines in step S61 that there is no surplus capacity of the air diffuser, the plant control device 10 outputs a command to increase the dosage of the flocculant related to the processing in step S4 or step S12. On the other hand, when the plant control apparatus 10 determines in step S61 that the air diffuser has a surplus capacity, the plant control apparatus 10 returns to step S60 and continues to evaluate the surplus capacity of the air diffuser. Thus, the plant control apparatus 10 controls the activated sludge so as to quickly obtain a preferable property.

  Thus, the operation management method for a wastewater treatment plant according to the sixth embodiment of the present invention numerically evaluates the power consumption efficiency of the air diffuser by performing the above-described calculation, and evaluates the margin (surplus capacity) of the wastewater treatment plant. Can do. Therefore, it can be determined whether or not the organic sludge can be further loaded on the activated sludge, and target management or raw water inflow management of the flocculation process can be performed.

  It should be noted that the operation management method for the wastewater treatment plant of the present invention is not limited to the above-described embodiment, and it is needless to say that various changes can be made without departing from the gist of the present invention. For example, an apparatus in which the aggregation reaction and the solid-liquid separation process are integrated may be used as the aggregation reaction processing apparatus, and an apparatus in which the aeration tank and the precipitation tank are integrated may be used as the activated sludge treatment apparatus. Further, in the coagulation treatment device and the activated sludge treatment device, the solid-liquid separation means is not limited to the sedimentation basin, and a membrane separation device may be employed.

The schematic block diagram which shows an example of the waste water treatment plant to which the operation management method of the waste water treatment plant of this invention is applied. The block diagram which shows the structure of the control part in the plant control apparatus shown in FIG. The flowchart which shows the control procedure of the operation management method of the wastewater treatment plant which concerns on 2nd embodiment of this invention applied to the wastewater treatment plant shown in FIG. The flowchart which shows the control procedure of the operation management method of the waste water treatment plant which concerns on 2nd embodiment of this invention following FIG. 3, and 6th embodiment of this invention following FIG. The figure which shows the principal part structure of the waste water treatment plant drawn to show an example of the mass balance monitoring method. The flowchart which shows the control procedure of the operation management method of the wastewater treatment plant which concerns on 3rd embodiment of this invention applied to the wastewater treatment plant shown in FIG. The flowchart which shows the control procedure of the operation management method of the waste water treatment plant which concerns on 5th embodiment of this invention applied to the waste water treatment plant shown in FIG. The flowchart which shows the control procedure of the operation management method of the waste water treatment plant which concerns on 5th embodiment of this invention following FIG. The flowchart which shows the control procedure of the operation management method of the waste water treatment plant which concerns on the 6th embodiment of this invention applied to the waste water treatment plant shown in FIG. The flowchart which shows the algorithm which determines the property of activated sludge from the signal level and amplitude of the detection signal which a scattered light sensor outputs.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Coagulation reaction processing tank 2 Coagulation sedimentation tank 3 Reservoir tank 4 Pump 5 Aeration tank 5a Aeration pipe 5b Blower 6 Sedimentation basin 7 Dehydrator 8 Sludge property sensor 9a Bypass valve 10 Plant control device 10b Sludge property judgment means 10a Aging change detection means 10c Control unit

Claims (4)

It is an operation management method for a wastewater treatment plant having an agglomeration reaction treatment apparatus at the front stage and an activated sludge treatment apparatus equipped with a solid-liquid separation means at the rear stage,
Mass balance monitoring means for obtaining an increase / decrease amount of the activated sludge per hour in the activated sludge treatment apparatus and a sludge concentration rate in the solid-liquid separation means,
A sludge property sensor for detecting the property of the activated sludge in the activated sludge treatment device so as to be quantifiable;
In the coagulation reaction treatment device according to the amount of sludge increase / decrease per hour in the activated sludge treatment device obtained by the mass balance monitoring means, the sludge concentration rate in the solid-liquid separation means and the property information of the activated sludge detected by the sludge property sensor. Control means for controlling the agglomeration reaction processing device for increasing / decreasing the COD component by increasing / decreasing the chemical injection amount, changing the concentration of the chemical solution, or changing the brand of the chemical solution and / or a part or all of the raw water flowing into the agglutination reaction processing device Raw water bypass control means for bypassing the activated sludge treatment apparatus and / or MLSS concentration adjusting means for adjusting the MLSS concentration of the activated sludge treatment apparatus by controlling the amount of excess sludge withdrawn from the activated sludge treatment apparatus,
Adjusting the load of the activated sludge treatment apparatus by at least one of the control means for controlling the agglomeration reaction treatment apparatus, the raw water bypass treatment control means, and the MLSS concentration adjusting means to make the activated sludge have a preferable property. Operation management method of wastewater treatment plant. An operation management method for a wastewater treatment plant according to claim 1 ,
The MLSS concentration adjusting means calculates a limit capability in the solid-liquid separation performance of the solid-liquid separation means, determines a control target value of the MLSS concentration of the activated sludge treatment apparatus based on the calculated result, and sets the control target value to the control target value. An operation management method for a wastewater treatment plant that controls the amount of excess sludge drawn from the activated sludge treatment apparatus accordingly. An operation management method for a wastewater treatment plant in which an agglomeration reaction treatment device, an activated sludge treatment device equipped with solid-liquid separation means, and a dehydrator for excess sludge concentration and dewatering are sequentially arranged from the front stage to the rear stage,
And mass balance monitoring means for determining a sludge concentration ratio in the activated sludge treatment the solid-liquid separation means and decrease the amount of sludge per hour in the apparatus,
A sludge property sensor for detecting the property of the activated sludge in the activated sludge treatment device so as to be quantifiable;
A dehydrating function monitoring means for detecting surplus processing capacity in the dewatering of sludge processed by the dehydrator,
Increase / decrease amount of activated sludge per hour in the activated sludge treatment device obtained by the mass balance monitoring means, sludge concentration rate in the solid-liquid separation means, property change of the activated sludge detected by the sludge property sensor and the dehydration Control means for controlling the agglomeration reaction processing apparatus for increasing / decreasing the COD component by increasing / decreasing the drug injection amount, changing the concentration of the chemical solution, or changing the brand of the chemical solution from the surplus processing capacity of the dehydrator detected by the functional force monitoring means, and / or Alternatively, a raw water bypass control means for bypassing part or all of the raw water flowing into the agglomeration reaction treatment device to the activated sludge treatment device and / or an activated sludge treatment device by controlling the amount of excess sludge withdrawn from the activated sludge treatment device MLSS concentration adjusting means for adjusting the MLSS concentration of
Adjusting the load of the activated sludge treatment device by at least one of the control means for controlling the agglomeration reaction treatment apparatus, the raw water bypass treatment control means, and the MLSS concentration adjusting means to make the activated sludge have a preferable property. An operation management method for a wastewater treatment plant. An operation management method for a wastewater treatment plant according to claim 3 ,
Further, a diffused surplus capacity detecting means for detecting surplus capacity of the diffuser in the activated sludge treatment apparatus,
Power consumption detecting means for detecting the power consumed by the diffuser and obtaining the power consumption efficiency of the diffuser,
The control means for controlling the agglomeration reaction processing apparatus is a medicine injection from the surplus capacity of the aeration apparatus detected by the aeration surplus capacity detection means and the power consumption efficiency of the aeration apparatus determined by the power consumption detection means. An operation management method for a wastewater treatment plant in which the COD component is increased or decreased by increasing or decreasing the amount, changing the concentration of the chemical, or changing the brand of the chemical.

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