JP3344435B2 - Preservative management method for aqueous liquids - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling preservation of an aqueous liquid. More specifically, the present invention relates to an antiseptic management method for performing antiseptic management means at an appropriate time by predicting the progress of spoilage of an aqueous liquid used for various industrial uses that are easily spoiled by microorganisms.

[0002]

2. Description of the Related Art For example, starch slurries used for surface sizing agents, coating colors, etc. in paper mills are:
It is prepared in a slurry dissolution tank and stored temporarily or for a predetermined period in a storage tank or the like thereafter. This storage period becomes longer, or the storage temperature fluctuates, and furthermore, due to the incorporation of microorganisms from other routes, the liquid substance rots,
Deterioration causes deterioration of properties such as generation of putrefaction odor and lowering of pH. It causes work obstacles such as blockage.

[0003] Also, many aqueous liquids used for industrial applications such as metal working oils, fiber oils, calcium carbonate slurries, and latexes, like the above-mentioned starch slurries, suffer from deterioration in quality and work problems due to spoilage by microorganisms. Cheap. Therefore, in the process of using these for industrial use, addition of a preservative is commonly used as a countermeasure against decay.

Further, in order to properly use these preservatives, methods for predicting and predicting the progress of decay of the liquid have been attempted. In other words, in order to prevent the odor of the decay of metalworking oil,
In addition, in order to control an aqueous liquid containing a biodegradable polymer, methods for measuring the oxidation-reduction potential have been proposed (see JP-A-58-101196 and JP-A-3-180529). . For another purpose, there has been proposed a method of measuring the amount of decrease in dissolved oxygen in a solution using an oxygen electrode in a container (see JP-A-63-15150).

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to improve a process in industrial use of an aqueous liquid. In particular, it is an object of the present invention to develop a method for accurately and promptly predicting the degree of decay of the liquid material in implementing appropriate preservative treatment measures for the liquid material.

The above two prior arts for measuring the oxidation-reduction potential meet the above-mentioned object similarly to the present invention. However, it is difficult to accurately and reproducibly predict the degree of decay, and in another example, only the measurement of the number of viable microorganisms is performed. Was not effective and appropriate.

[0007] The inventors of the present invention have been based on the well-known knowledge that spoilage of an aqueous liquid substance is caused by the organic matter contained as a component thereof being degraded, denatured, etc. due to the living action of microorganisms in the liquid. In predicting the degree of the decay, the number of viable microorganisms in the liquid and the oxidation-reduction potential and the pH value, which have been generally attempted, have been measured, and the correlation between this and the degree of the decay has been measured. Experiment,
investigated.

[0008] That is, with respect to the degree of decay of the aqueous liquid material, these measured values with time generally show a change only at the end of decay progress in the case of pH, and relatively early in the case of viable cell count. May show a corresponding change, but often show a time-dependent value that is not related to the degree of decay,
Furthermore, in the case of the oxidation-reduction potential, the change is slow and tends to shift to the latter stage with respect to the progress of putrefaction, and in any case, it is not appropriate as a method for accurately and appropriately predicting the correlation with the progress of putrefaction. Was recognized.

From the results of this study, the inventors of the present invention have taken a further step in consideration of the conventional knowledge that the decay phenomenon of these liquids is attributable to the growth of microorganisms as one factor. Based on the consideration that the progress of decay is further promoted when the activity of these microorganisms is maintained active, the consumption of dissolved oxygen in the liquid, which is a nutrient source for maintaining the activity of the microorganisms, is now considered. Inspired by the measurement of the amount, as a result of intensive experimentation and examination, it was confirmed that the measured value over time was closely correlated with the degree of decay, leading to the present invention.

[0010]

According to the present invention, there is provided a method for predicting the degree of decay of an aqueous liquid material and performing management processing means, wherein the amount of dissolved oxygen in the aqueous liquid material contained in the open system container is measured with time. A method for controlling the preservation of an aqueous liquid material is provided, comprising measuring the value and predicting the degree of decay of the liquid material based on the measured value.

The term "aqueous liquid material" used in the present invention refers to an aqueous liquid material used for industrial use, particularly a so-called spoilage such as decomposition or denaturation by various microorganisms, which impairs the product value or causes a spoilage phenomenon. It is an aqueous liquid which is likely to hinder the work process as it progresses, and includes starch slurry, starch paste, metalworking oil, fiber oil, aqueous paint, calcium carbonate slurry, latex and the like.

[0012] The term "management treatment means" used in the present invention refers to a method for stabilizing and maintaining the aqueous liquid material, such as addition of a preservative, addition and replenishment of a newly prepared aqueous liquid material, or washing of a container. It means well-known and commonly used means. In the present invention, these treatment means are carried out based on the prediction based on the measurement result of the dissolved oxygen amount of the liquid material over time.

[0013] Of these management treatment means, it is simple to carry out the means by adding a preservative, and it is particularly preferable in that not only the progress of putrefaction can be surely prevented, but also the property before putrefaction can be recovered. As the preservative to be added, any preservative can be used as long as it can recover the dissolved oxygen amount value (hereinafter abbreviated as DO value) once decreased by the addition of the normal concentration. Known preservatives (such as industrial bactericides, bacteriostats and fungicides)
Is raised.

For example, methylenebisthiocyanate, 5-
Chloro-2-methyl-4-isothiazolin-3-one, 4,5-dichloro-2-n-octyl-isothiazolin-3-one, 1,2-benzoisothiazolin-3-one, hexahydro-1,3,5 -Tris (2-hydroxyethyl) -s-triazine, 2-bromo-2-nitropropane-1,3-diol, 2,2-dibromo-2-nitro-1
-Ethanol, 2,2-dibromo-3-nitrilopropionamide, 1,2-bis (bromoacetoxy) ethane, 1,2-bis (bromoacetoxy) propane, 1,4-bis (bromoacetoxy) -2-butene , N-bromoacetamide, bistribromomethylsulfone, α-chloro-O-acetoschibenzaldoxime, α-chlorobenzaldoxime, dichloroglyoxime, 4,5-dichloro-1,2-dithiol-3-one, etc. Is raised.

In the present invention, the prediction of decay / recovery of an aqueous liquid material is made by grasping the change in the amount of oxygen consumed by the microorganisms in the liquid to carry out daily activities as a time-dependent DO value. Measurement of the DO value is required to be performed on an aqueous liquid contained in an open system container in which a necessary amount of oxygen is always dissolved in order to maintain the activity of the microorganism. That is, the "open-system container" herein refers to a container that is not substantially sealed so that the liquid surface of the aqueous liquid comes into contact with air and oxygen can always be supplied into the liquid.

In the present invention, since it is necessary to quickly determine the time-dependent DO value corresponding to the degree of decay of the aqueous liquid, the measurement is carried out using an oxygen electrode conventionally used for DO value measurement. It is recommended that here,
The `` oxygen electrode '' is preferably a known one having a configuration of a diaphragm type galvanic cell, utilizing the principle that the current flowing when oxygen passes through the gas permeable membrane is proportional to the amount of oxygen. Is used in an aqueous liquid storage tank or the like in the use process, or is used in an experimental vessel continuously sampled at appropriate intervals from the storage tank or the like. That is, the DO value is measured by measuring the DO value of the aqueous liquid contained in the open container continuously or with time using the oxygen electrode.

In the present invention, when predicting the degree of decay of the aqueous liquid material, the meaning of the DO value over time is extremely remarkable and distinctive. That is, the DO value is an index for accurately and proactively indicating the degree of decay of the liquid material or the state from the decay state to the normal state.

More specifically, when the DO value over time is in the process of decreasing, but clearly fluctuates with the rate of decrease, it suggests that the liquid material has signs of spoilage. However, when the time value further decreases and reaches an approximate value of 0, already at that time, or after a short time thereafter, it is confirmed that the liquid material is surely causing decay. be able to. However, depending on the type of the aqueous liquid, the time-dependent value may not reach the approximate value of 0. In this case, the relationship between the DO value of the target aqueous liquid and the degree of decay is determined in advance. It is necessary to understand.

The confirmation of this phenomenon differs depending on the type of the aqueous liquid. For example, in the case of starch slurry, a deposit is generated and adheres to the vessel wall. In the case of metal working oil, It is recognized that there was a putrefaction phenomenon due to generation of offensive odor, decrease in pH, emulsification destruction and the like.

On the other hand, when the DO value with time is leveling after maintaining the level or temporarily decreasing, the liquid material is controlled normally or the decay stops and its properties recover. This suggests that the above-mentioned decay phenomenon has not been observed, or that the decay phenomenon that has occurred has stopped and further decay does not proceed. The degree of progress of spoilage of water-based liquids under various conditions varies greatly depending on the kind of the liquids. Therefore, the time required to measure DO values over time to determine their degree of decay, or a prediction of recovery, cannot be determined, but can be suggested with the rate of increase or decrease, which is generally In the case of starch slurry, it can be determined empirically within 30 minutes.

Thus, in the present invention, based on the prediction based on the measurement result of the DO value over time in the aqueous liquid,
The above-mentioned necessary management processing for stopping the progress of putrefaction of the liquid material at an early stage and recovering the liquid property to normal is performed. However, without accurately and quickly predicting the process by which the decay of the aqueous liquid proceeds, when the present invention is not carried out, the decay of the liquid proceeds excessively,
It is no longer possible to restore the liquid property to normal, which leads to loss of aqueous liquid material and work trouble.

Further, the method of the present invention is not limited to predicting the progress of decay of an aqueous liquid material, and it is also possible to check the state where the liquid material is normally controlled and the decay is not progressing by horizontally shifting the DO value with time. It is also possible to predict the progress of the initial putrefaction that is stopped by the implementation of the antiseptic management method and recovers normally by confirming the rise of the DO value over time. Thereby, it is possible to confirm the result of the management processing means. Thus, the present invention provides an industrially effective and practical method for controlling preservation of aqueous liquids.

[0023]

Examples and Comparative Examples Next, embodiments and effects of the present invention will be described in detail with reference to examples and reference examples.

Example 1 A slurry liquid (solid content concentration: 16.5%) prepared by using industrial water as oxidized starch was used as a test sample, and 4 kg of this sample was circulated by the circulation device shown in FIG. Was added. For the sample, the pH in the solution, the oxidation-reduction potential (O
RP), dissolved oxygen (DO) and viable cell count were measured continuously or over time. In addition, a resin net was hung on the pit of the apparatus, and the presence or absence of attached matter was examined with time. The result is shown in FIG. The viable cell count is determined by the standard plate culture method (30
C, 48 hours) using a colony counter. The measurement of the oxidation-reduction potential is carried out by using Toa Denpa Kogyo Co., Ltd.
The measurement was performed using a TS-304A type ORP composite electrode. Also,
The dissolved oxygen amount was measured using an OE-383 type oxygen electrode manufactured by Toa Denpa Kogyo KK. As is evident from the test results, the formation of deposits was observed about 9 hours after the DO value decreased with time and reached the approximate value of 0. pH or OR
In the case of the P value, even if an attempt is made to predict the degree of progress of decay, the change is slow, and at the time of the change, it can be seen that decay has progressed considerably. The viable cell count has the same tendency as the ORP value, but it takes 48 hours to measure the viable cell count. Therefore, it can be seen that the degree of decay cannot be quickly predicted.

Example 2 A slurry liquid (solid concentration: 10%, pH 4.8) prepared by using industrial water with cationic starch was used as a test sample.
kg was put into a beaker, and 10 g of putrefied starch slurry was added while stirring with a stirrer. Example 1
In the same manner as described above, the dissolved oxygen content (DO) in the solution, the number of viable bacteria, and the presence or absence of extraneous matter were measured continuously or with time. When the DO value reached an approximate value of 0, 2,2 -Dibromo-3
-Nitrilopropionamide (DBNPA) was added at 10 ppm. The result is shown in FIG. From the test results, when the DO value reaches the approximate value of 0, when an effective amount of a bactericide is added,
It can be seen that the DO value increases. This is because the DO value is measured in an open system, and the amount of oxygen that has been consumed by the bacterium is reduced by the killing of the bacterium and the decrease in the activity of the bacterium, and becomes less than the dissolved amount of oxygen in the air. It is considered that it was. On the 5th day after the start of the test, the DO value decreased,
At the time when the approximate value was reached, if no management treatment was performed, the formation of deposits was observed about 15 hours later. At the time of the formation of the deposits, spoilage has progressed considerably, and it has been confirmed that the properties of the spoilage are not restored by the addition of a further fungicide. The measurement of the DO value of the present invention indicates that the effective period of the fungicide can be determined.

Example 3 A slurry liquid (solid content: 25) was prepared by using industrial water for oxidized starch and further adjusting the pH to 7.0 using sodium hydroxide.
%) Was used as a test sample. 3 ppm of 5-chloro-2-methyl-4-isothiazolin-3-one (MIT) was added to this sample as a bactericide.
The spoiled oxidized starch slurry obtained from the paper mill was added to 1%. 1 kg of the sample thus prepared was placed in a beaker, stirred with a stirrer, and the dissolved oxygen content (DO) in the liquid, the number of viable bacteria, and the presence or absence of attached matter were measured continuously or with time in the same manner as in Example 1. The same amount of spoiled product was added 24 and 48 hours after the start of the test. The test results are shown in FIG. Before the elapse of 48 hours from the start of the test, there was almost no change in the DO value, which indicates that the fungicide was effective. However, it can be seen that the number of viable bacteria changes considerably with the addition of putrefactive products.
This indicates that the DO value does not correspond to the change in the number of viable bacteria but to the degree of decay.
In this example, deposits occurred about 9 hours after the DO value reached the approximate value of 0. Considering the above points, it is considered that the progress of spoilage occurs not depending on the number of viable bacteria but on the activity of the fungi. Therefore, it is considered that the prediction of the degree of decay cannot be determined only by measuring the number of viable bacteria in the liquid.

Example 4 Kaolin: 75 parts by weight, calcium carbonate: 25 parts by weight, SB
1 kg of a papermaking coating color having a solid content concentration of 60% by weight, comprising 7 parts by weight of R latex, 7 parts by weight of urea phosphorylated starch and 0.4 parts by weight of sodium polyacrylate, was prepared. A 1% by weight of a decay solution of a coating color collected from a certain paper mill was added thereto to obtain a test sample. This test sample was collected in a beaker, stirred at a water temperature of 30 ° C. with a stirrer, and the pH, redox potential (ORP), dissolved oxygen amount (DO) and viable cell count in the solution were measured in the same manner as in Example 1. It was measured continuously or over time. The result is shown in FIG. As is clear from the test results, the DO value decreases with time,
Approximately 12 hours after the time when the approximate value was reached, generation of putrefaction odor was confirmed. In the case of pH or ORP value, even if an attempt is made to predict the degree of progress of decay, no change can be confirmed and it can be seen that the prediction is impossible. In addition, the number of viable bacteria has the same tendency as the DO value, but it takes 48 hours to measure the number. Therefore, it can be seen that the degree of decay cannot be quickly predicted.

Example 5 Mineral oil: 70 parts by weight, oleic acid: 4.5 parts by weight, triethanolamine: 3 parts by weight, Ionet MO-600 (trade name of a surfactant manufactured by Sanyo Chemical Industries, Ltd.): 7.5 parts by weight Parts and Ionette S-80 (trade name of a surfactant manufactured by Sanyo Chemical Industries, Ltd.): 15 parts by weight was prepared, and the composition was diluted 20-fold with industrial water. Further, 1% by weight of a putrefaction liquid used as a cutting oil was added to obtain a test sample. This test sample was collected in a beaker, stirred at a water temperature of 30 ° C. with a stirrer, and the pH and oxidation-reduction potential (O
RP), dissolved oxygen (DO) and viable cell count were measured continuously or over time. FIG. 6 shows the result. As is evident from the test results, the generation of suspended matter was confirmed about 18 hours after the DO value decreased with time and reached the approximate value of 0. In the case of pH or ORP value, even if an attempt is made to predict the degree of progress of decay, no change can be confirmed and it can be seen that the prediction is impossible. In addition, the viable cell count tends to increase up to 48 hours after the start of the test, but tends to decrease after 48 hours, indicating that the correlation with the degree of decay is not clear.

[0029]

INDUSTRIAL APPLICABILITY The present invention is provided for industrial use, and during storage or processing of an aqueous liquid substance which is easily spoiled by microorganisms, the normal storage management state, the progress of spoilage and spoilage are stopped, and the property is restored. Predict conditions early and accurately,
The process control including the prevention of decay progress was surely performed, and the rot loss of the aqueous liquid material was prevented, and the operation of the process was maintained.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a circulation device used in the present invention.

FIG. 2 is a graph showing time-dependent measurement of pH, ORP, DO, and viable cell count of an oxidized starch slurry.

FIG. 3 is a graph showing time-dependent measurement of changes in DO and viable cell count of a cationic starch slurry by adding a preservative.

FIG. 4 is a graph showing time-dependent measurement of DO and viable cell count by adding a spoiled product at regular intervals to an oxidized starch slurry to which a preservative has been added.

FIG. 5: pH of coating color (1% rot solution added),
FIG. 3 is a graph showing the measurement of ORP, DO, and viable cell count over time.

Fig. 6 pH, ORP, DO of cutting oil (1% spoiled liquid added)
And a graph showing the measurement of the number of viable bacteria over time.

────────────────────────────────────────────────── (5) References JP-A-56-108951 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01N 33/18 C12Q 3/00 G01N 33 / 10 G01N 33/28 JICST file (JOIS)

Claims (6)

(57) [Claims] 1. A method for predicting the degree of spoilage of an aqueous liquid and performing a management treatment means, wherein the amount of dissolved oxygen in the aqueous liquid contained in the open system container is measured with time, and the amount is determined based on the measured value. An antiseptic management method for an aqueous liquid material, comprising predicting the degree of decay of the liquid material. 2. The management method according to claim 1, wherein the aqueous liquid is an aqueous liquid which is easily decayed by microorganisms such as starch slurry, starch paste, metal working oil, fiber oil, calcium carbonate slurry and latex. 3. The management method according to claim 1, wherein the open container is a container that is not substantially sealed. 4. The management method according to claim 1, wherein the dissolved oxygen amount is measured using an oxygen electrode. 5. The management method according to claim 1, wherein the degree of decay of the aqueous liquid is predicted when the measured value of the dissolved oxygen falls with time and reaches an approximate value of 0 in the aqueous liquid. 6. The management method according to claim 1, wherein the management processing means is an addition of a preservative.