JP6863130B2 - Chemical injection control method and chemical injection control device for deodorant for sludge - Google Patents

Description

The present invention relates to a method for controlling chemical injection of a deodorant for sludge and a chemical injection control device.

Odors generated from sludge include ammonia, methyl mercaptan, hydrogen sulfide, methyl sulfide, methyl disulfide, etc. Among them, hydrogen sulfide is a typical malodorous substance and is used for sewage treatment plants and factory wastewater treatment facilities. Causes residents' complaints. In addition, hydrogen sulfide is not only harmful to the human body, but also corrodes metals and concrete. Therefore, in order to ensure the health and safety of workers and to maintain equipment, it is required to surely remove hydrogen sulfide. The amount of hydrogen sulfide generated in sludge varies depending on the properties of sludge and the residence time in a storage tank. Furthermore, throughout the year, the generation of hydrogen sulfide fluctuates even more due to seasonal fluctuations in sludge temperature.

Under such circumstances, measures to prevent the generation of hydrogen sulfide, oxidatively decompose hydrogen sulfide, prevent gasification of hydrogen sulfide into the gas phase, and add a hydrogen sulfide remover to sludge have been widely implemented. It was. However, with regard to the chemical injection adjustment of the hydrogen sulfide remover, rough chemical injection adjustment such as increasing or decreasing the chemical injection amount based on the result of spot-measurement of the hydrogen sulfide concentration with a gas detector tube or the like has been performed.

On the other hand, in Patent Document 1, the concentration of the odorous component generated from the sludge is detected by a gas sensor, and the chemical injection amount of the deodorant supplied from the storage tank of the deodorant to the sludge is controlled based on the detection signal. A control device equipped with a pump has been proposed.

Further, in Patent Document 2, the odor gas concentration measurement method and analysis method are devised in consideration of the drawbacks of Patent Document 1, and deodorization based on the more accurate odor gas concentration measurement result, which is not easily affected by the external environment. A method for controlling drug injection has been proposed.

Further, Patent Document 3 describes a method for controlling hydrogen sulfide generated from pumped sewage, which includes water temperature, storage tank water level, and wastewater when a hydrogen sulfide remover such as ferric chloride is added to the sewage. A chemical injection method has been proposed in which the dissolved oxygen concentration is measured and the operation of the chemical injection pump is synchronously controlled with the operation of the water supply pump based on these measured values.
Further, in Patent Document 4, when adding a hydrogen sulfide remover such as nitrate to sewage, the flow rate and temperature of wastewater and the concentration of hydrogen sulfide in the storage tank or pump well are measured, and from the measured value of the water flow rate. Calculate the residence time in the water supply pipe or the total residence time in the water supply pipe and the storage tank or pump well, and sulfide to wastewater based on the measured value of water temperature and hydrogen sulfide concentration and the calculated value of residence time. A method for determining the amount of hydrogen sulfide added has been proposed.
Further, Patent Document 5 proposes a method of determining the amount of nitrate added to wastewater containing organic pollutants based on the residence time of wastewater, COD, TOC and oxidation-reduction potential.

Further, in Patent Document 6, in order to prevent hydrogen sulfide generated from sewage or sludge, the value measured by an odor sensor by sucking the gas in the space vapor phase portion and the measured value of the electrical conductivity of sewage or sludge are used. A method of controlling the injection of the hydrogen sulfide remover has been proposed.

Japanese Unexamined Patent Publication No. 4-35718 Japanese Unexamined Patent Publication No. 8-71311 Japanese Unexamined Patent Publication No. 7148482 Japanese Unexamined Patent Publication No. 10-328676 U.S. Patent Application Publication No. 5,114,587 Japanese Unexamined Patent Publication No. 2003-94070

However, since the proposal of Patent Document 1 is a device for adjusting the amount of the deodorant added according to the concentration of the odorous component diffused into the air from the sludge, the diffusion state of the odorous component in the gas phase and ventilation. Depending on the situation and the influence of wind, the concentration of odorous components in the gas phase and the amount of odorous components contained in sludge may not correlate. Therefore, there is a drawback that the relationship between the measured odor component concentration and the required amount of the deodorant does not match, resulting in excessive or under-drug injection.

Since the proposal of Patent Document 2 is a control that feeds back the generated odorous gas concentration to the deodorant drug injection amount, it is suitable for the drug injection control of a slow-acting hydrogen sulfide remover that takes a long time to develop the effect. It was unsuitable. In addition, since it is a control method based on the concentration measurement result of hydrogen sulfide gas diffused in the gas phase, it has a drawback that it is not suitable for controlling the chemical injection of a hydrogen sulfide remover into sludge before hydrogen sulfide diffuses as a gas. there were.

The objects to which the deodorant is added in Patent Documents 3 to 5 are premised on wastewater and sewage, and there is no reference to sludge with a large amount of solids and microorganisms. There was a drawback that it could not be done, or even if it could be done, the accuracy was low.
Further, since sludge in which hydrogen sulfide has already been generated is in an environment in which dissolved oxygen does not exist, it is not effective to use the dissolved oxygen concentration as an index for chemical injection control as in Patent Document 3.
Further, since the work of measuring COD and TOC as proposed in Patent Document 4 is complicated and time-consuming, it is not realistic as a method of controlling the chemical injection of the hydrogen sulfide remover in the field.

In short, the conventional patent documents 1 to 6 determine the chemical injection amount of the hydrogen sulfide remover based on the odor component concentration, hydrogen sulfide concentration, temperature, residence time, dissolved oxygen, COD, TOC, electrical conductivity, etc., and control the chemical injection. It is suggested to do. When the chemical injection of a hydrogen sulfide remover is started based on the result of hydrogen sulfide generated in an odor source such as a sludge storage tank, the deodorizing effect is delayed because the response is after the occurrence. If the deodorant effect is delayed, there is a risk that the amount and frequency of odors generated throughout the year will increase. In addition, if an excessive amount of hydrogen sulfide remover is injected in order to rapidly develop or sustain the deodorant effect, there is a risk that the amount of the drug used increases.
Therefore, it is not possible or possible to apply the chemical injection control method in the conventional proposal to sludge containing solids generated in sewage treatment plants and factory wastewater treatment facilities where hydrogen sulfide has already been generated. Even so, it had the drawback of low accuracy.

However, in the proposal of Patent Document 6, although it is considered possible to predict the amount of chemical injection of the hydrogen sulfide remover on sludge to some extent, the influence of temperature, which most affects the generation of hydrogen sulfide, is not considered, and the chemical injection control is performed. The accuracy of was low.
Further, Patent Document 6 describes that the liquid temperature of sewage and sludge does not fluctuate significantly throughout the year and is not important as a control factor. However, since the liquid temperature fluctuates from 10 ° C to 15 ° C throughout the year, it is considered to be very important as a control factor.

Here, hydrogen sulfide generated from sludge in a sewage treatment plant or an industrial wastewater treatment facility fluctuates depending on the sludge temperature and the sludge property temperature. In particular, the generation status of hydrogen sulfide fluctuates greatly depending on the season. Therefore, there is a problem that a hydrogen sulfide remover for sludge is wasted due to excessive chemical injection in winter.
In order to improve these, it has been proposed to control the hydrogen sulfide remover based on the generated hydrogen sulfide gas concentration, water temperature, residence time of the object, dissolved oxygen concentration, and the like.
However, the conventional proposal has a problem that it cannot be applied to the chemical control of the hydrogen sulfide remover for sludge containing solids generated in sewage treatment plants and industrial wastewater treatment plants, or even if it can be done, the accuracy is low. there were.

Therefore, it is a main object of the present invention to provide a drug control method and a drug injection control device capable of improving the efficiency of using a deodorant for sludge and stabilizing the deodorant effect throughout the year.

As a result of diligent studies, the present inventors have determined the standard sludge temperature, standard solid concentration, standard sludge pH, and standard chemical injection amount in the on-site sludge treatment system regarding the chemical injection of deodorants for sludge. Set as appropriate, from (1) the value obtained by subtracting the standard sludge temperature from the sludge temperature, (2) the coefficient determined by the sludge pH value, and / or (3) the value obtained by dividing the sludge solids concentration by the standard sludge solids concentration. By calculating the multiplier value and multiplying this multiplier value by the standard chemical injection amount to determine the chemical injection amount, the efficiency of using deodorants for sludge should be improved and deodorant measures should be taken stably throughout the year. We found that we could do it, and completed the present invention.
That is, the present invention is as follows.

[1] This is a chemical injection control method in which a deodorant is injected into an odor source containing sludge, and the standard chemical injection is based on the relationship between the value obtained by subtracting the standard sludge temperature from the sludge temperature and the coefficient determined by the sludge pH value. A chemical injection control method in which a multiplier value of an amount is calculated, the multiplier value is multiplied by a reference chemical injection amount to determine a chemical injection amount of a deodorant, and the chemical injection amount is injected into an aqueous system.
[2] The chemical injection control according to the above [1], wherein the multiplier value of the reference chemical injection amount is calculated based on the relationship obtained by adding a value obtained by dividing the sludge solid concentration by the standard sludge solid concentration to the above relationship. Method.
[3] The chemical injection control method according to the above [1] or [2], wherein the formula for calculating the chemical injection amount of the deodorant is any one of the following formulas (1) and (2).
Drug injection amount = standard drug injection amount
× (coefficient determined from sludge pH value) ^{(sludge temperature-reference sludge temperature)} ... Equation (1)
Chemical injection amount = standard chemical injection amount x (coefficient determined from sludge pH value) ^{(sludge temperature-reference sludge temperature)}
× (Sludge solids concentration ÷ Standard sludge solids concentration)… Equation (2)
[4] The chemical injection control method according to any one of [1] to [3] above, which is a chemical injection control method for sludge having a sludge pH of 4.0 to 7.5.
[5] The chemical injection control method according to any one of the above [1] to [4], wherein the range of the coefficient determined by the sludge pH value is 1.01 to 1.20.
[6] The chemical injection control method according to any one of [1] to [5] above, which is a chemical injection control method for a hydrogen sulfide remover generated from an odor source containing sludge.
[7] The chemical injection control method according to any one of the above [1] to [6], wherein the deodorant contains nitrite or a salt thereof.
[8] Calculate the multiplier value of the standard chemical injection amount based on the relationship between the value obtained by subtracting the standard sludge temperature from the sludge temperature and the coefficient determined by the sludge pH value, and multiply the multiplier value by the standard chemical injection amount to deodorize the deodorant. A chemical injection control device for a deodorant injected into a deodorant source containing sludge, comprising a control unit having a chemical injection control means for determining the chemical injection amount of the deodorant.
[9] The relationship is
Drug injection amount = standard drug injection amount
× (coefficient determined from sludge pH value) ^{(sludge temperature-reference sludge temperature)} ... Equation (1)
Is represented by, or
In addition to the above relationship, a value obtained by dividing the sludge solids concentration by the reference sludge solids concentration is added, and the relationship is as follows.
Chemical injection amount = standard chemical injection amount x (coefficient determined from sludge pH value) ^{(sludge temperature-reference sludge temperature)}
× (Sludge solids concentration ÷ Standard sludge solids concentration)… Equation (2)
The drug injection control device according to the above [8], which is represented by.

According to the present invention, it is possible to provide a drug control method and a drug injection control device capable of improving the efficiency of using a deodorant for sludge and stabilizing the deodorant effect throughout the year.

It is the schematic which shows an example of the drug control apparatus which concerns on embodiment of this invention provided in the sludge treatment system. It is the schematic which shows an example of the drug control apparatus which concerns on embodiment of this invention provided in the sludge treatment system. It is the schematic which shows an example of the drug control apparatus which concerns on embodiment of this invention provided in the sludge treatment system. It is a figure which showed the sludge pH for obtaining an example of the "coefficient determined by sludge pH" of this embodiment, and the addition rate necessary for a deodorant. It is a figure which shows an example of the curve created by plotting the "coefficient determined by sludge pH" of this embodiment for each "sludge pH".

Hereinafter, modes for carrying out the present invention will be described. It should be noted that the embodiments described below show an example of typical embodiments of the present invention, and the scope of the present invention is not limited and interpreted thereby.

1. 1. Chemical injection control method according to the embodiment of the present invention The chemical injection control method according to the embodiment of the present invention is a chemical injection control method in which a deodorant is injected into an odor source containing sludge. Then, in the chemical injection control method of the present embodiment, the multiplication value of the reference chemical injection amount is calculated based on the relationship between the "value obtained by subtracting the reference sludge temperature from the sludge temperature" and the "coefficient determined by the sludge pH value". The method includes multiplying the multiplier value by the reference drug injection amount to determine the drug injection amount of the deodorant: and ordering the drug injection amount to be injected into the aqueous system.
This makes it possible to calculate an appropriate amount of chemical injection for stabilizing the deodorant effect. Then, the efficiency of using the deodorant for sludge can be improved, and the deodorizing effect can be stabilized throughout the year.

Further, the multiplier value of the reference chemical injection amount is obtained by dividing the sludge solid concentration by the standard sludge solid concentration in addition to the "sludge temperature minus the standard sludge temperature" and the "coefficient determined by the sludge pH value". It is preferable that the value is calculated based on the added relationship.
Specifically, based on the relationship between "the value obtained by subtracting the standard sludge temperature from the sludge temperature", "the coefficient determined by the sludge pH value", and "the value obtained by dividing the sludge solids concentration by the standard sludge solids concentration". , It is preferable to calculate the multiplier value of the reference drug injection amount.
Even if the sludge temperature fluctuates greatly throughout the year, it is possible to calculate a more appropriate chemical injection amount for stabilizing the deodorizing effect.

Further, it is preferable that the present embodiment is a chemical injection control method for a remover for hydrogen sulfide generated from sludge containing solid matter in a sewage treatment plant or a factory wastewater treatment facility.
As shown in [Example] below, it has been demonstrated that hydrogen sulfide, which is regarded as important as an odor, can be efficiently removed to the deodorization target level with a limited amount of hydrogen sulfide remover. Was done.
As described above, according to the present embodiment, it is possible to efficiently and surely remove hydrogen sulfide to the level of the deodorizing target with a limited amount of the hydrogen sulfide remover, and to stabilize the effect throughout the year. It becomes.

The chemical injection control method of the present embodiment calculates a multiplier value of the reference chemical injection amount based on the relationship between "a value obtained by subtracting the reference sludge temperature from the sludge temperature" and "a coefficient determined by the sludge pH value", or " Based on the relationship between "the value obtained by subtracting the standard sludge temperature from the sludge temperature", "the coefficient determined by the sludge pH value", and "the value obtained by dividing the sludge solids concentration by the standard sludge solids concentration", the multiplier value of the standard chemical injection amount is calculated. calculate.
Then, the drug injection control method of the present embodiment multiplies the calculated multiplier value by the reference drug injection amount to determine the drug injection amount to be injected into the water system.

In the chemical injection control method of the present embodiment, it is preferable that the formula for calculating the chemical injection amount of the deodorant is any one of the following formulas (1) and (2).

Drug injection amount = standard drug injection amount
× (coefficient determined from sludge pH value) ^{(sludge temperature-sludge reference temperature)} ... Equation (1)
Chemical injection amount = standard chemical injection amount x (coefficient determined from sludge pH value) ^{(sludge temperature-reference sludge temperature)}
× (Sludge solids concentration ÷ Standard sludge solids concentration)… Equation (2)

In the formula (1), the multiplier value is a value calculated with the "coefficient determined by the sludge pH value" as the base and the "value obtained by subtracting the reference sludge temperature from the sludge temperature" as the power index. The formula (1) is preferably applied to an aqueous system in which the sludge solid concentration is adjusted within a predetermined range.

In the above formula (2), the power value is calculated with the "coefficient determined by the sludge pH value" as the base and the "value obtained by subtracting the reference sludge temperature from the sludge temperature" as the power index, and "sludge solid matter". It is a value multiplied by "a value obtained by dividing the concentration by the standard sludge solids concentration".

In a water system (particularly a sludge treatment system), when a device or means capable of adjusting and managing the sludge solids concentration within a predetermined range is provided, the measured sludge solids concentration and the standard sludge solids concentration are substantially the same. It becomes. When the "value obtained by dividing the measured sludge solids concentration by the reference sludge solids concentration" is close to 1, the above formula (1) can be adopted. In the present embodiment, the determination of the reference sludge solid matter concentration, the measurement of the sludge solid matter concentration, and the input thereof can be omitted, so that the workability is good.
As this "approximate to 1", for example, when "the value obtained by dividing the sludge solids concentration by the reference sludge solids concentration" is 1 ± 0.1 to 0.01, it is more preferably 1 ± 0.05 to 0. The case of 0.01 can be mentioned.
Further, even when the above formula (2) is adopted in such a water system "approximate to 1", the "value obtained by dividing the sludge solids concentration by the reference sludge solids concentration" may be set to "1" in advance. .. Further, in the above equation (2), when the range of "approximate to 1" is exceeded, the setting of "1" may be canceled in advance.

[Measured value of this embodiment]
Here, the "sludge temperature", "sludge solids concentration", and "sludge pH value" in the present embodiment are sensors and the like for the sludge temperature, solids concentration, and pH value in the water system (particularly near the sludge storage tank). It is a value measured by the measuring meter of. The measured value is the value measured when the deodorant is injected into the water system, or the average value of the measured values (for example, the measured values from 1 hour to 24 hours before) before the deodorant is injected into the water system. Is desirable.
Each measuring meter may be one that is generally used in an aqueous system. In addition, each measuring meter may be installed in a place generally installed in a water system. Further, when measuring the collected sludge, a measuring meter that can be used in a desk test may be used.

It is preferable that each measured value of sludge in the chemical injection control method of the present embodiment meets the following conditions because the required chemical injection amount can be set accurately and the deodorizing target can be achieved. Further, the water system may be adjusted so as to be within a suitable range of each measured value.
The pH of the sludge is preferably 4 to 10, more preferably 4.0 to 7.5.
The range of the coefficient determined by the sludge pH value is preferably 1.01 to 1.30, more preferably 1.01 to 1.20, and further preferably 1.04 to 1.17.
The sludge temperature is preferably 5 to 42 ° C, more preferably 10 to 38 ° C, and even more preferably 15 to 33 ° C.
The sludge solid concentration is preferably 0.1 to 5.5%, more preferably 0.2 to 5%, and even more preferably 1 to 4%.

[Reference value of this embodiment]
In the present embodiment, the reference values of each reference numerical value (reference sludge temperature, reference sludge solid concentration, reference sludge pH, and reference drug injection amount) can be predetermined as follows.
Each reference value can be set by the monthly average value in the water system (particularly the sludge treatment system), and it is preferable to use the monthly average value in spring or autumn when the climate is stable, for example, from March to April. It can be used by referring to the monthly averages from May, October to November.

In addition, in the collected sludge, the sludge temperature, sludge pH, and sludge solid concentration when the required amount of deodorant was determined by a desk test were determined as "reference sludge temperature", "reference sludge pH", and "reference", respectively. It can be "sludge solids concentration".

In addition, the "standard chemical injection amount" is the required amount of deodorant that can achieve the actual deodorizing target with the actual machine (actual equipment) of the water system (particularly sludge treatment system) at the site. In the present embodiment, an appropriate amount of drug injection is required by adjusting the required amount of this deodorant by a special factor.
As the reference drug injection amount, a value that can be actually achieved may be set by performing preliminary work on the actual machine (actual equipment). When setting the reference drug injection amount by actual machine measurement, for example, inject the deodorant to be actually used into the actual equipment while changing the injection amount, check the actual deodorant effect at each injection amount, and deodorize the target. The value of the injection amount of the deodorant that can actually achieve the above can be set as the "reference drug injection amount".
Further, as the reference drug injection amount, a value that can be actually achieved or a value that is highly likely to be actually achieved by adding the insufficient drug injection amount may be set based on the water system management data at the site. For example, it can be set as the "reference drug injection amount" based on the amount of drug used in the spring or autumn of last year's management data.

It is desirable to appropriately set the deodorizing target for each water system (particularly sludge treatment system) at the site, thereby improving the efficiency of using the deodorant for sludge at each site and achieving the deodorizing effect throughout the year. Can be stabilized.

The required amount of the deodorant can be determined by a desk test or by an actual machine test used in an on-site water system.
Examples of the odor that is the target of the deodorization target include hydrogen sulfide and the like. It is particularly effective when hydrogen sulfide is targeted in the present embodiment.

The deodorant target when determined by a desk test is, for example, that the deodorant effect lasts longer than the control target time after the drug injection (sustainability); the deodorant effect appears within the control target time after the drug injection. (Immediate effect) and the like. Of these, in the present embodiment, it is particularly effective when sustainability is set as a deodorant target.

The deodorization target when determining in the actual machine test is, for example, that the odor concentration at a specific location does not exceed the control target concentration; the average value of the odor concentration at the specific location does not exceed the control target concentration; the odor concentration at the specific location Does not exceed the target concentration more than a certain frequency. In the present embodiment, it is particularly effective when the average odor concentration is set as the control target and when the frequency of the odor concentration is set as the control target.

The required amount of deodorant is strongly related to the sludge temperature. Therefore, when determining the reference chemical injection amount, the accuracy will be higher if the test is carried out under the condition that the sludge temperature is close to the annual average sludge temperature. Thus, determining one factor makes it difficult to regulate the other. Therefore, the sludge temperature, sludge pH value, and sludge solid concentration when the required amount of deodorant is determined by the test are defined as "reference sludge temperature", "reference pH value", and "reference sludge solid concentration". Is preferable.

Further, as the setting of each reference value, for example, each reference value can be set based on the water system management data for each site. It is also possible to set each reference value based on the data recorded in the past water system management. Further, each reference value may be set based on the water system management data of a similar water system (for example, the sludge temperature is close, the deodorizing concentration of the deodorizing target is close, etc.).

Specifically, if a deodorant is currently used and there is an annually designed drug usage amount, the daily average or monthly average of the drug usage amount assuming that the drug usage amount is used throughout the year, Based on the sludge temperature, sludge pH value and sludge solids concentration, these can be appropriately set as reference values. In addition, a desk test or the like may be performed under the conditions such as the amount of drug used in the above assumption, and a reference value may be set based on the result.

Whether or not the deodorization target has been achieved can be confirmed by measuring the odor gas concentration of the sludge. In the present embodiment, the concentration of odorous gas generated from the surface of sludge may be measured, but it is desirable to measure the concentration of odorous gas contained in sludge. By measuring the odorous gas concentration in the sludge, a more accurate injection amount can be obtained.

The odor and odor gas concentration can be measured by a measuring method generally used in an aqueous system. As the measurement method, for example, a container (gas sampler, sludge collector, etc.), a gas suction pump, or the like can be used, and various sensors, gas chromatography, a gas detector tube, or the like can be used for the measurement. In addition, the concentration of odorous gas in sludge can be measured by the headspace method because it is simple and accurate.
<Measurement method of headspace method>
〔procedure〕
50 mL of sludge is collected in a PET bottle with a volume of 500 mL, and sealed with a lid processed so that gas detector tube measurement is possible. Shake the PET bottle up and down 10 times or more to release the odorous gas in the sludge to the headspace side. Connect the gas detector tube and the gas sampler for the gas detector tube, suck the gas, and measure the concentration of odorous gas.

[Determining value of this embodiment]
In the present embodiment, "sludge solids concentration ÷ reference sludge solids concentration" and "sludge temperature-sludge reference temperature" can be determined based on the above-mentioned measured values and reference values.
Further, the "coefficient determined from the sludge pH value" can be determined as follows.

[Constant determined by sludge pH]
The coefficient determined by the sludge pH is based on the numerical value of the rate of increase in the required amount of deodorant when the temperature rises in the sludge pH. The coefficient determined by the sludge pH is preferably set appropriately for each on-site water system (particularly the sludge treatment system).
The required amount of deodorant (mg / L) in the coefficient is the amount of deodorant that can achieve the deodorizing target, and can be changed according to the deodorizing target. The required amount of deodorant here is different from the chemical injection amount or the reference chemical injection amount of the above formula (1) or (2), and is for calculating a coefficient determined by sludge pH.

Further, it is more preferable that the coefficient determined by the sludge pH is based on the value obtained by obtaining the power root of the numerical value of the increase rate of the required amount of the deodorant. The power root is preferably a "predetermined temperature rise difference", but is not particularly limited. For example, when the predetermined temperature rise difference is "10 ° C.", it is preferable to use "10th root" as the root of the power. Further, the "predetermined temperature rise difference" can be calculated by the above-mentioned sludge temperature a (° C.)-Sludge temperature b (° C.) (a> b) at the time of temperature rise, and one of them is the reference sludge temperature. There may be.

In the chemical injection control method of the present embodiment, the constant determined by the sludge pH is preferably the following formula (3).
Coefficient determined by sludge pH =
^{(Predetermined temperature rise difference)} √ Deodorant required rise rate value ... Equation (3)

Specifically, one "coefficient determined by sludge pH" is calculated by multiplying the numerical value of the increase rate of the required amount of deodorant when a predetermined temperature rises under a certain sludge pH condition. can do. For example, as shown in FIG. 5, when the sludge of the water system (particularly the sludge treatment system) has a pH of 5.3, the coefficient determined by the sludge pH is 1.08, and this 1.08 is used in the sludge pH 5.3 of the present embodiment. It can be determined as a "coefficient determined by sludge pH" used for calculating the amount of chemical injection.
The determined value of the "coefficient determined by the sludge pH value" determined here can be input into the above formula (1) or the formula (2) to calculate the "drug injection amount".

Further, it is desirable to calculate each "value rooted to the power of the increase rate of the required amount of deodorant when a predetermined temperature rises" for each sludge pH. Then, the rooted value for each sludge pH (see, for example, Table 2) can be plotted on a graph, and adjacent plots can be connected to create a curve (see, for example, FIG. 5). When creating the curve, acid or alkali is added to the sludge, the sludge pH is changed to the target pH, the rooted value of the root for each sludge pH is calculated, plotted on a graph, and adjacent to each other. It may be created by connecting the plots. Based on the curve (hereinafter, also referred to as “coefficient curve”), the “coefficient determined by sludge pH” used for calculating the drug injection amount of the present embodiment can be determined.
For example, the actually measured sludge pH value is input to the sludge pH on the X-axis of the coefficient curve, and from the coefficient determined by the sludge pH on the Y-axis corresponding to this sludge pH value, "the coefficient determined by the sludge pH value". Can be determined.
The determined value of the "coefficient determined by the sludge pH value" determined here can be input into the above formula (1) or the formula (2) to calculate the "drug injection amount".

2. The drug injection control device according to the embodiment of the present invention The drug injection control device of the present embodiment is a drug injection control device including a control unit having the above-described drug injection control means of the present embodiment.
Further, in the present embodiment, a multiplier value of the reference chemical injection amount is calculated based on the relationship between the value obtained by subtracting the reference sludge temperature from the sludge temperature and the coefficient determined by the sludge pH value, and the multiplier value is multiplied by the reference chemical injection amount. It is a chemical injection control device for a deodorant that is injected into a deodorant source containing sludge, comprising a control unit having a chemical injection control means for determining the chemical injection amount of the deodorant. The drug injection control device may be a general-purpose computer such as a personal computer equipped with a CPU, or a server existing on a network.

The drug injection control method of the present embodiment described above is stored as a program in a hardware resource including a control unit including a CPU of the device and a storage medium (USB memory, HDD, CD, network server, etc.). It can also be realized by the control unit.
Further, the present embodiment can be a program for operating a computer as the drug injection control method of the above-described present embodiment.

In the control unit, (a) the measured value of the sludge temperature or the determined value of "the value obtained by subtracting the reference sludge temperature from the sludge temperature"; (b) the measured value of the sludge pH or "the coefficient determined by the sludge pH value". Of the determined values; and (c) the measured value of the sludge solids concentration; or the determined value of "the value obtained by dividing the sludge solids concentration by the reference sludge solids concentration"; It is preferable that (a) to (c) are automatically input or manually input.
The control device of the present embodiment may appropriately include necessary parts among the measurement meter units and / or the determination value determination units, but each of these measurement unit units and / or each determination value determination unit may be provided. It may be in a state where it exists outside the control device and is accessible to the control unit.

The present embodiment may be a drug addition adjusting device including the drug injection control device and a drug addition device such as a pump.
Further, the present embodiment can be a water system or a water system system including the drug injection control device or the drug addition control device.

As an example, the drug control device 1a of the present embodiment will be specifically described with reference to FIG. 1, but the present invention is not limited thereto.
As shown in FIG. 1, the drug control device 1a is provided with a control unit 2a having the drug injection control means of the present embodiment described above. The control unit 2a adjusts the chemical injection pump 6 for injecting the chemicals in the chemical storage tank 5 into the sludge storage tank 7, and controls the injection amount of the deodorant to the deodorant source containing sludge. doing.
Further, the pH sensor 3 measures the sludge pH value by directly contacting the sludge in the sludge storage tank 7 with a pH meter. The temperature sensor 4 measures the sludge temperature by bringing a thermometer into direct contact with the sludge in the sludge storage tank 7. The pH sensor 3 and the temperature sensor 4 may be provided in the sludge pipe 10. The sludge solids concentration sensor 9 is installed in the sludge pipe 10 after the sludge pump 8 that sends sludge from the sludge storage tank 7 to the dehydrator 11, and measures the sludge solids concentration in the sludge pipe with a sludge solids concentration meter. ..
The pH sensor 3, the temperature sensor 4, and the sludge solids concentration sensor 9 transmit the measured or determined values as detection signals to the control unit 2a for input.

The control unit 2a appropriately accesses a storage unit (not shown) inside or outside the control unit to appropriately access various information data (for example, each measurement value, each reference value, each determination value, each) regarding the present embodiment. Correspondence, etc.) can be read or a write command can be issued. Examples of each reference value include a reference chemical injection amount, a reference sludge temperature, a reference sludge solids concentration, a reference pH value, and the like. Further, as each correspondence, the correspondence between the constant determined by the sludge pH and the sludge pH, the coefficient curve, the above equations (1) to (3) and the like can be mentioned.

The control unit 2a inputs the measurement results of the sludge pH value, sludge temperature, and sludge solid concentration at the site into the formulas (2) and / or the formula (3) to determine the drug injection amount. When the sludge solids concentration control device is provided so that the sludge solids concentration is substantially constant, the value obtained by dividing the measured sludge solids concentration by the reference sludge solids concentration is considered to be close to 1. (1) or formula (3) may be used.
The control unit 2a commands the chemical injection amount to the chemical injection pump 6, and causes the chemical injection pump 6 to inject the chemical from the chemical storage tank 5 into the sludge storage tank 7 which is an odor generation source. As a result, it is possible to improve the efficiency of using chemicals for sludge and stabilize the deodorizing effect throughout the year.

Further, as an example, the drug control device 1b of the present embodiment will be specifically described with reference to FIG. 2, but the present invention is not limited thereto. The description of the drug injection control device 1a will be omitted as appropriate.
As shown in FIG. 2, the drug control device 1b of the present embodiment is provided with a control unit 2b that controls drug injection to an odor source.
The sludge temperature sensor 12 measures the temperature transmitted to the surface of the sludge pipe 10 as the sludge temperature with a thermometer. At this time, when the sludge temperature sensor 12 measures the temperature transmitted to the surface of the sludge pipe 10 immediately after the outlet of the sludge storage tank 7, it is closer to the actual sludge temperature and can be measured with high accuracy. It is preferable to provide it in the sludge pipe immediately after the outlet of the tank 7. The setting unit 13 of the coefficient based on the sludge pH value is based on the measured sludge pH value based on the correspondence between the “sludge pH” and the “coefficient determined by the sludge pH” (see FIG. 5 as an example). Determine the determination value of "the coefficient determined by the sludge pH value".
The sludge solids concentration sensor 9 is as described above.
The sludge solids concentration sensor 9, the sludge temperature sensor 12, and the sludge pH coefficient setting unit 13 transmit the measured or determined values as detection signals to the control unit 2b for input.

The control unit 2b appropriately accesses a storage unit (not shown) inside or outside the control unit to read or write various information data (for example, each reference value, each correspondence, etc.) regarding the present embodiment. Can give orders. The control unit 2b does not have to have a coefficient setting unit 13 determined from the sludge pH value, and may be in a state of being accessible to the setting unit 13.
The control unit 2b inputs the measurement result of the sludge temperature, the sludge solid concentration, and the determination value of the coefficient based on the sludge pH value into the formula (2) or the formula (1) to determine the drug injection amount.
The control unit 2b commands the chemical injection amount to the chemical injection pump 6, and causes the chemical injection pump 6 to inject the chemical from the chemical storage tank 5 into the sludge storage tank 7 which is an odor generation source. As a result, it is possible to improve the efficiency of using chemicals for sludge and stabilize the deodorizing effect throughout the year.

Further, as an example, the drug control device 1c of the present embodiment will be specifically described with reference to FIG. 3, but the present invention is not limited thereto. The description of the drug injection control devices 1a and 1b will be omitted as appropriate.
As shown in FIG. 3, the drug control device 1c of the present embodiment is provided with a control unit 2c that controls drug injection to an odor source.
Further, the sludge concentration setting value setting unit 14 calculates the sludge solids concentration setting value from the measured sludge solids concentration measurement and sets the value. The temperature sensor 9 and the coefficient setting unit 13 based on the sludge pH value are as described above.
The sludge pH coefficient setting unit 13 and the sludge concentration setting value setting unit 14 transmit the measured or determined values as detection signals to the control unit 2c for input.

The control unit 2c appropriately accesses a storage unit (not shown) inside or outside the control unit to read or write various information data (for example, each reference value, each correspondence, etc.) regarding the present embodiment. Can give orders. The control unit 2c does not have to have the sludge pH value setting unit 13 and / or the sludge concentration setting value setting unit 14, and can access the setting unit 13 and / or the setting unit 14. It suffices if it is in a good state.
The control unit 2c inputs the measurement result of the sludge temperature at the site, the coefficient based on the sludge pH value, and the sludge solid concentration setting value into the formula (2) or the formula (1) to determine the amount of the drug to be injected.
The control unit 2c commands the chemical injection amount to the chemical injection pump 6, and causes the chemical injection pump 6 to inject the chemical from the chemical storage tank 5 into the sludge storage tank 7 which is an odor generation source. As a result, it is possible to improve the efficiency of using chemicals for sludge and stabilize the deodorizing effect throughout the year.

The embodiment according to the present invention may have the following configuration.
[1] This is a chemical injection control method in which a deodorant is injected into an odor source containing sludge, and the standard chemical injection is based on the relationship between the value obtained by subtracting the standard sludge temperature from the sludge temperature and the coefficient determined by the sludge pH value. A chemical injection control method in which a multiplier value of an amount is calculated, the multiplier value is multiplied by a reference chemical injection amount to determine a chemical injection amount of a deodorant, and the chemical injection amount is injected into an aqueous system.
[2] The chemical injection control according to the above [1], wherein the multiplier value of the reference chemical injection amount is calculated based on the relationship obtained by adding a value obtained by dividing the sludge solid concentration by the standard sludge solid concentration to the above relationship. Method.
[3] The chemical injection control method according to the above [1] or [2], wherein the formula for calculating the chemical injection amount of the deodorant is any one of the following formulas (1) and (2).
Drug injection amount = standard drug injection amount
× (coefficient determined from sludge pH value) ^{(sludge temperature-reference sludge temperature)} ... Equation (1)
Chemical injection amount = standard chemical injection amount x (coefficient determined from sludge pH value) ^{(sludge temperature-reference sludge temperature)}
× (Sludge solids concentration ÷ Standard sludge solids concentration)… Equation (2)
[4] The chemical injection control method according to any one of [1] to [3] above, which is a chemical injection control method for sludge having a sludge pH of 4.0 to 7.5.
[5] The chemical injection control method according to any one of the above [1] to [4], wherein the range of the coefficient determined by the sludge pH value is 1.01 to 1.20.
[6] The chemical injection control method according to any one of [1] to [5] above, which is a chemical injection control method for a hydrogen sulfide remover generated from an odor source containing sludge.
[7] The chemical injection control method according to any one of the above [1] to [6], wherein the deodorant contains nitrite or a salt thereof.
[8] The coefficient determined by the sludge pH is based on a value obtained by raising the root of the increase rate of the required amount of deodorant when the temperature rises at the sludge pH, according to the above [1] to [7]. The drug injection control method according to any one.
[9] The chemical injection control method according to any one of the above [1] to [8], wherein the coefficient determined by the sludge pH is the following formula (3).
Coefficient determined by sludge pH =
^{(Predetermined temperature rise difference)} √ Deodorant required rise rate value ... Equation (3)

[10] Calculate the multiplier value of the standard chemical injection amount based on the relationship between the value obtained by subtracting the standard sludge temperature from the sludge temperature and the coefficient determined by the sludge pH value, and multiply the multiplier value by the standard chemical injection amount to deodorize the deodorant. A chemical injection control device for a deodorant injected into a deodorant source containing sludge, comprising a control unit having a chemical injection control means for determining the chemical injection amount of the deodorant.
[11] The relationship is
Drug injection amount = standard drug injection amount
× (coefficient determined from sludge pH value) ^{(sludge temperature-reference sludge temperature)} ... Equation (1)
Is represented by, or
In addition to the above relationship, a value obtained by dividing the sludge solids concentration by the reference sludge solids concentration is added, and the relationship is as follows.
Chemical injection amount = standard chemical injection amount x (coefficient determined from sludge pH value) ^{(sludge temperature-reference sludge temperature)}
× (Sludge solids concentration ÷ Standard sludge solids concentration)… Equation (2)
The drug injection control device according to the above [10], which is represented by.
[12] The chemical injection control device according to the above [10] or [11], wherein the control unit controls based on the sludge treatment management method according to the above [1] to [9].
[13] A water system or a water system system including the chemical injection control device according to any one of the above [9] to [12].

An embodiment of the present invention will be described with reference to the following examples and comparative examples. The scope of the present invention is not limited to the examples.

[Test Example 1]
The present inventors have stated that the chemical requirement is strongly dependent on the sludge temperature; this sludge temperature dependence varies depending on the sludge pH; the sludge temperature becomes more dependent as the sludge pH approaches neutrality. I'm getting it empirically.
Therefore, the present inventors pay attention to the numerical value of the increase rate of the deodorant required amount when the temperature rises in the sludge pH, further use the temperature difference as the numerical value of the power root, and use the power root of the value of the rise rate as the value of the power root. It was determined, and using this as a coefficient determined by the sludge pH, it was examined whether it could be used to control the amount of chemical injection in the water system.
The target of the deodorizing effect was to set the amount of deodorant added, which can maintain the concentration of hydrogen sulfide generated from sludge to 10 ppm or less for 6 hours, as the required amount of deodorant added. The hydrogen sulfide concentration was measured by collecting 50 mL of sludge in a PET bottle having a volume of 500 mL and using the headspace method described above.
The sludge used was the water-based sludge shown in Table 1 below. As the hydrogen sulfide remover, a nitrite-based hydrogen sulfide remover was used.
The results obtained are shown in Table 2 and FIG. Furthermore, as shown below, the 10th root of the rate of increase in the required amount of deodorant was used as a coefficient determined by the sludge pH, and plots were made for each pH, which is shown in FIG.

1. 1. The sludge pH is adjusted to 4 to 7, and the required amount of deodorant added at 25 ° C. and 15 ° C. for each sludge is determined.
-The required amount of deodorant added was set so that the deodorant effect lasted for 6 hours.
-For the deodorizing effect, the acceptance condition was that the concentration of hydrogen sulfide generated by the headspace method was 10 ppm or less.
2. At each pH, the rate of increase in the required amount of deodorant when the temperature rises by 10 ° C. is determined.
3. 3. The coefficient determined by the sludge pH is calculated by obtaining the 10th root of the rate of increase in the required amount of deodorant.
Deodorant requirement increase rate when the temperature rises by 10 ° C = (coefficient determined by sludge pH) ^{(25 ° C-15 ° C)} = (coefficient determined by sludge pH) ⁽¹⁰⁾

[Example 1 and Comparative Example 1]
1. 1. Site information ・ Site: Sludge treatment process at sewage treatment plant ・ Sludge dewatering amount: Approximately 113,000 m ^{3 per year}
2. Hydrogen sulfide remover treatment-The purpose of Example 1 was to reduce the load on the deodorizing device and suppress corrosion of the equipment inside the storage tank, and it was confirmed whether the hydrogen sulfide concentration inside the sludge storage tank could be reduced. Deodorant target: The monthly average concentration of hydrogen sulfide was set to less than 20 ppm.
-Hydrogen sulfide remover: A nitrite-based hydrogen sulfide remover was used.
-Chemical injection method: A hydrogen sulfide remover was injected into the sludge storage tank.
3. 3. Confirmation of hydrogen sulfide removal effect ・ Measurement method: A hydrogen sulfide sensor was installed inside the sludge storage tank, and the hydrogen sulfide concentration was continuously measured.
-A diffusion type hydrogen sulfide concentration meter was used as the hydrogen sulfide sensor.
-Measurement interval: The hydrogen sulfide gas concentration was measured, and the average value was recorded once every 15 minutes. Data was collected from the sensor data logger every month and the average value was confirmed.

4. Measurement of control factors ・ Measurement of sludge temperature: A thermocouple thermometer was installed in the sludge supply pipe from the storage tank to the dehydrator, and the continuously measured measured values were signaled to the control device.
-Measurement of sludge solids concentration: A sludge solids concentration meter was installed in the sludge supply pipe from the storage tank to the dehydrator, and the continuously measured measured values were signaled to the control device.
-Measurement of sludge pH: The pH of the sampled sludge was measured with a pH meter, and a constant determined for each site by the sludge pH was numerically input to the control device.

5. Examination of Example 1 and Comparative Example 1 In Example 1, (1) the value obtained by subtracting the reference sludge temperature from the sludge temperature, (2) the value obtained by dividing the sludge solid concentration by the standard sludge solid concentration, and (3) the sludge. The amount of the hydrogen sulfide remover was determined based on the coefficient determined by pH, and the injection was controlled.
Specifically, the drug injection amount was determined as follows.
In Example 1, an actual machine test was carried out in April, and each reference value was determined. That is, the average value of sludge temperature, the average value of sludge solid concentration, the average value of sludge pH, and the average value of deodorant required amount in April were used as standard values. Specifically, the standard sludge temperature was set at 21.5 ° C.: the standard sludge solid concentration was 3.1%: the standard sludge pH value was 5.7: the standard drug injection amount was 122 (kg / day).
Next, the sludge temperature, sludge pH, and sludge solid concentration on the implementation date in May are measured, and if the measured values are as follows, these values and the reference value are input to the formula (2) and the implementation date. The dose of the drug was determined.
-The measured sludge temperature was 23.2 ° C.
-Coefficient determined by sludge pH value: From the measured sludge pH 5.5, the coefficient determined by sludge pH was determined to be 1.083 by inputting to the graph of FIG.
-The measured sludge solid concentration was 2.9%.

Chemical injection amount = standard chemical injection amount x (coefficient determined from sludge pH value) ^{(sludge temperature-reference sludge temperature)}
× (Sludge solids concentration ÷ Standard sludge solids concentration)… Equation (2)
Therefore, the drug injection amount of Example 1 was determined as follows.
Drug injection amount = 122 x (1.083) ^(23.2-21.5) x (2.9 / 3.1) = 131 (kg / day)

・ Measured sludge temperature 23.1 ℃
Chemical injection amount = standard chemical injection amount x (sludge temperature ÷ standard sludge temperature)
Drug injection amount = 130 x (23.1 / 21.5) = 140 (kg / day)

Tests were conducted throughout the year for Example 1 and Comparative Example 1 (Table 3).
In Comparative Example 1, when the chemical injection of the hydrogen sulfide remover was controlled only by the temperature, the hydrogen sulfide concentration inside the storage tank was suppressed to an average of 22.3 ppm per year.
However, in Comparative Example 1, the hydrogen sulfide concentration was high in July to October, and the amount of the hydrogen sulfide remover was insufficient. In winter, the hydrogen sulfide concentration was sufficiently low, and the hydrogen sulfide remover was excessively added. In Comparative Example 1, it could not be said that the deodorant effect was stable.

On the other hand, in Example 1, when controlled by the amount of chemical injection of the hydrogen sulfide remover calculated using the sludge temperature, sludge solid concentration, and sludge pH value, the monthly average concentration of hydrogen sulfide inside the storage tank is less than 20 ppm. The deodorant target was achieved. Further, in Example 1, the hydrogen sulfide concentration inside the storage tank was 10 ppm on average annually, which was less than 1/2 of that of Comparative Example 1.
In Example 1, the hydrogen sulfide concentration in July-October was stably reduced, and the difference in hydrogen sulfide concentration between summer and winter was reduced. The deodorant effect was more stable than in Comparative Example 1. In Example 1, the removal effect was stable even when the amount of the hydrogen sulfide remover used was almost the same.
From this, by using the method of the present embodiment, the hydrogen sulfide concentration inside the sludge storage tank can be reduced, and finally the efficiency of chemical use for sludge is improved, and the deodorizing effect is stably performed throughout the year. It was proved that it can be done.

[Example 2 and Comparative Example 2]
1. 1. Site information ・ Site: Sludge treatment process at sewage treatment plant ・ Sludge dewatering amount: Approximately 40,000 m ^{3 per year}
2. Deodorant treatment-The purpose of this Example 2 is to ensure the safety of workers, specifically, to reduce the regulation value of oxygen deficiency prevention regulations to 10 ppm or less, and the hydrogen sulfide concentration around the dehydrator. It was confirmed whether it could be reduced.
-Hydrogen sulfide remover: Nitrite-based drug-Chemical injection method: Hydrogen sulfide remover was injected into the sludge storage tank.
3. 3. Confirmation of deodorizing effect ・ Measurement method: A hydrogen sulfide sensor was installed above the dehydrating agent reaction tank of the belt press dehydrator, and the hydrogen sulfide concentration was continuously measured.
-A diffusion type hydrogen sulfide concentration meter was used as the hydrogen sulfide sensor.
-Measurement interval: The hydrogen sulfide gas concentration was measured, and the average value was recorded once every 15 minutes (96 data / day). Data were collected from the sensor data logger every month, and the maximum concentration of hydrogen sulfide and the number of times the hydrogen sulfide exceeded 10 ppm were totaled. The number of data was 96 per day.

4. Measurement of control factors-Measurement of sludge temperature: Similar to Example 1, the temperature transmitted to the surface of the sludge pipe 10 immediately after the outlet of the sludge storage tank 7 was measured, and the continuously measured measured values were signal-input to the control device.
-Measurement of sludge solids concentration: Not reflected in the control (because a centrifugal concentrator was introduced in the sludge concentration process and there was almost no fluctuation in sludge solids concentration).
-Measurement of sludge pH: The pH of the sampled sludge was measured with a pH meter, and a constant determined by the sludge pH was numerically input to the control device.

5. Example 2 and Comparative Example 2
In Example 2, the chemical injection amount of the hydrogen sulfide remover was determined from (1) the value obtained by subtracting the reference sludge temperature from the sludge temperature, and (2) the coefficient determined for each site by the sludge pH, and the chemical injection was controlled. Specifically, the drug injection amount was determined as follows.
-The measured sludge temperature was 22.4 ° C.
-Coefficient determined by sludge pH value: From the measured sludge pH 5.8, the coefficient determined by sludge pH was determined to be 1.093 by inputting to the graph of FIG.

Drug injection amount = standard drug injection amount ×
(Coefficient determined from sludge pH value) ^{(Sludge temperature-sludge reference temperature)} ... Equation (1)
Therefore, the drug injection amount of Example 2 was determined as follows.
Drug injection amount = 40 x (1.093) ^(22.4-21.2) = 45 (kg / day)

-Measured sludge temperature: 22.4 ° C
Chemical injection amount = standard chemical injection amount x (sludge temperature ÷ standard sludge temperature)
Drug injection amount = 40 x (22.4 / 20.9) = 43 (kg / day)
Hydrogen sulfide 10 ppm = the regulated concentration of the regulations for the prevention of oxygen deficiency.

Tests were conducted throughout the year for Example 2 and Comparative Example 2 (Table 4).
In Comparative Example 2, when the deodorant injection was controlled only by the temperature, the hydrogen sulfide concentration in the space above the mixing tank was 19 ppm at the maximum. In Comparative Example 2, the number of times the oxygen deficiency prevention rule exceeded 10 ppm was 47 times a year.
On the other hand, in Example 2, when the deodorant injection was controlled by a constant determined for each site by the temperature and sludge pH, the hydrogen sulfide concentration was reduced to a maximum of 4 ppm as compared with Comparative Example 2. In Example 2, the 10 ppm of the regulation for preventing oxygen deficiency and the like was not exceeded throughout the year.
In Example 2, the maximum concentration of hydrogen sulfide is reduced to about 1/5 of that of the prior art, and the hydrogen sulfide regulation concentration of 10 ppm is not exceeded in the regulations for preventing oxygen deficiency, etc. Was stable.
From this, it was demonstrated that by using the method of the present embodiment, it is possible to improve the efficiency of the use of chemicals for sludge and to stably perform the deodorizing effect throughout the year.

1a, 1b, 1c Chemical injection control device, 2a, 2b, 2c: Control unit, 3 pH sensor, 4 temperature sensor, 5 Chemical storage tank, 6 Chemical injection pump, 7 Sludge storage tank, 8 Sludge pump, 9 Sludge solids Concentration sensor, 10 sludge piping, 11 dehydrator, 12 temperature sensor, 13 sludge pH value setting unit 14 sludge concentration setting value setting unit

Claims (9)

It is a chemical injection control method that injects a deodorant into an odor source including sludge.
Calculate the multiplier value of the standard chemical injection amount based on the relationship between the value obtained by subtracting the standard sludge temperature from the sludge temperature and the coefficient determined by the sludge pH value, and multiply the multiplier value by the standard chemical injection amount to administer the deodorant. A drug injection control method in which an amount is determined and the drug injection amount is injected into an aqueous system. The chemical injection control method according to claim 1, wherein the multiplier value of the reference chemical injection amount is calculated based on the relationship obtained by adding a value obtained by dividing the sludge solids concentration by the standard sludge solids concentration to the above relationship. The chemical injection control method according to claim 1 or 2, wherein the formula for calculating the chemical injection amount of the deodorant is any one of the following formulas (1) and (2).
Drug injection amount = standard drug injection amount
× (coefficient determined from sludge pH value) ^{(sludge temperature-reference sludge temperature)} ... Equation (1)
Chemical injection amount = standard chemical injection amount x (coefficient determined from sludge pH value) ^{(sludge temperature-reference sludge temperature)}
× (Sludge solids concentration ÷ Standard sludge solids concentration)… Equation (2) The chemical injection control method according to any one of claims 1 to 3, which is a chemical injection control method for sludge having a sludge pH of 4.0 to 7.5. The chemical injection control method according to any one of claims 1 to 4, wherein the range of the coefficient determined by the sludge pH value is 1.01 to 1.20. The chemical injection control method according to any one of claims 1 to 5, which is a chemical injection control method for a hydrogen sulfide remover generated from an odor source containing sludge. The chemical injection control method according to any one of claims 1 to 6, wherein the deodorant contains nitrite or a salt thereof. Calculate the multiplier value of the standard chemical injection amount based on the relationship between the value obtained by subtracting the standard sludge temperature from the sludge temperature and the coefficient determined by the sludge pH value, and multiply the multiplier value by the standard chemical injection amount to inject the deodorant. A chemical injection control device for a deodorant injected into a deodorant source containing sludge, comprising a control unit having a chemical injection control means for determining the amount. The above relationship
Drug injection amount = standard drug injection amount
× (coefficient determined from sludge pH value) ^{(sludge temperature-reference sludge temperature)} ... Equation (1)
Is represented by, or
In addition to the above relationship, a value obtained by dividing the sludge solids concentration by the reference sludge solids concentration is added, and the relationship is as follows.
Chemical injection amount = standard chemical injection amount x (coefficient determined from sludge pH value) ^{(sludge temperature-reference sludge temperature)}
× (Sludge solids concentration ÷ Standard sludge solids concentration)… Equation (2)
The drug injection control device according to claim 8, which is represented by.

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